JP5946399B2 - Electric disc brake device - Google Patents

Description

  The present invention relates to an improvement in an electric disc brake device that brakes an automobile using an electric motor as a drive source. Specifically, it is intended to realize a structure capable of shortening the time required for generating the braking force and increasing the generated braking force.

  The electric disc brake device that uses an electric motor as a drive source eliminates the need for piping compared to a hydraulic disc brake that has been widely used in the past, and facilitates manufacturing and reduces costs. Research is being conducted because it has many advantages, such as the fact that used brake fluid is not generated and the environmental load is small, and that there is no movement of the brake fluid, so that responsiveness can be improved. In such an electric disc brake device, it is necessary to convert the rotational motion of the electric motor into linear motion while increasing the force, and to strongly press the pair of pads against both side surfaces of the rotor. In view of such circumstances, conventionally, various electric disc brake devices in which a gear type reduction device and a booster device are combined have been proposed, for example, as described in Patent Documents 1 to 4. .

  FIG. 8 shows an example of a conventional structure described in Patent Documents 1 and 2 among them. In this electric disc brake device, like an ordinary hydraulic disc brake, an inner pad 2 and an outer pad 3 are installed so as to be capable of displacement in the axial direction of the rotor 1 with the rotor 1 rotating together with the wheels interposed therebetween. ing. For this purpose, a support (not shown) is supported on the vehicle body (fixed to a knuckle constituting the suspension device) in a state adjacent to the rotor 1. The inner and outer pads 2, 3 are in a state where the rotor 1 is sandwiched from both sides in the axial direction, and the axial direction (the outer side is the outside in the width direction of the vehicle body when assembled to the vehicle body, and the inner side is Similarly, the center side is also referred to, and the axial direction refers to the axial direction of the rotor 1 unless otherwise specified, both of which are the same throughout the present specification and claims). It is supported by the support.

  Moreover, the caliper 4 is assembled to the support so as to be capable of displacement in the axial direction. The caliper 4 is provided with a caliper claw 5 at an outer side end portion and a cylinder space 6 inside an inner side portion. The caliper pawl 5 is made to face the outer side surface of the outer pad 3 and the inner pad 2 is pressed toward the inner side surface of the rotor 1 by a thrust generating device 7 provided in the cylinder space 6. ing. At the time of braking, when the inner pad 2 is pressed against the inner side surface of the rotor 1 by the thrust generating device 7, the caliper 4 is displaced toward the inner side, and the caliper claw 5 moves the outer pad 3 toward the outer side surface of the rotor 1. Press. As a result, the rotor 1 is strongly clamped from both sides in the axial direction, and braking is performed. The above configuration and operation are the same as those of a widely used hydraulic disc brake.

  In the case of the electric disc brake device, the electric motor 8 is used as a drive source to press the inner pad 2 against the inner side surface of the rotor 1 so as to press the output shaft 9 of the electric motor 8 and the inner side surface of the inner pad 2. Are provided with a gear type speed reducer 10, the thrust generating device 7, and a piston 11. The rotational force decelerated by the speed reducer 10 and increased in torque is transmitted to the drive-side rotor 13 constituting the ball-and-ramp type booster device via the feed screw device 12. Rotate. The drive-side rotor 13 is moved to the outer side by the function of the feed screw device 12 until the clearance between the inner and outer pads 2 and 3 and the side surface of the rotor 1 is eliminated. Translate. On the other hand, after the gap is eliminated and the function of the feed screw device 12 is stopped, it rotates. Then, a plurality of drive side ramp grooves 14, 14 provided on the outer side surface of the drive side rotor 13 and a plurality of driven sides provided on the inner side surface of the driven side stator 15 attached to the inner side surface of the piston 11. Based on the engagement (rolling contact) between the side lamp grooves 16 and 16 and the plurality of balls 17 sandwiched between the lamp grooves 14 and 16, the driving side rotor 13 and the driven side stator 15. Expand the distance between and with great force. As a result, the outer side surface of the piston 11 is strongly pressed against the inner side surface of the inner pad 2.

  In the electric disc brake device having the conventional structure as described above, it is not always possible to sufficiently increase the braking force associated with pressing both the pads 2 and 3 against both side surfaces of the rotor 1. Of course, by increasing the speed reduction ratio of the speed reducer 10, increasing the speed reduction ratio of the feed screw device 12 (thinning the screw pitch), or reducing the inclination angle of the ramp grooves 14, 16. It is possible to increase the braking force. However, when the reduction ratio of the speed reducer 10 or the feed screw device 12 is increased, the pads 2 and 3 are advanced from the non-braking state position to the brakeable position, and the linings 18 and 18 of both the pads 2 and 3 are moved. The time required to press against both side surfaces of the rotor 1 becomes longer. That is, in the non-braking state, a clearance (clearance) exists between the both side surfaces of the rotor 1 and the friction surfaces of the linings 18 and 18, so that this clearance is eliminated in order to exert a braking force. There is a need. If the reduction ratio is increased, the time required to eliminate this clearance becomes longer, and the responsiveness of the electric disc brake device deteriorates.

  Patent Documents 3 and 4 describe an invention related to an electric disc brake device that uses the elasticity of a spring, increases the elasticity by a force-increasing mechanism such as a lever, and presses the pad lining against the rotor. . Among these, the invention described in Patent Document 3 increases the elasticity of the spring to generate a braking force and releases the braking based on energization of the solenoid. Such a structure of the invention described in Patent Document 3 is considered to be limited in use as a braking device for automobiles because the braking force cannot be adjusted. The structure of the invention described in Patent Document 4 generates a braking force by balancing the ball cam mechanism and the elasticity of the leaf spring. Such a structure is considered to be limited in use as a braking device for automobiles because, for example, it is necessary to increase the size of the ball cam mechanism in order to obtain a large braking force.

JP 2004-169729 A JP 2010-265971 A Japanese Patent No. 2511957 US Patent Application Publication No. 2010/0243387

  The present invention has been invented in order to realize a structure capable of increasing the generated braking force and making it a realistic size as an automobile braking device in view of the circumstances as described above.

The electric disc brake device of the present invention includes a rotor, a pad support portion, a pair of pads, a pressing piece, and an electric actuator.
Of these, the rotor rotates with the wheels.
The pad support portion is supported by the vehicle body in a state adjacent to the rotor. The pad support portion corresponds to a support in the case of a floating caliper type disc brake device, and corresponds to a caliper in the case of an opposed piston type disc brake.
The two pads are supported by the pad support portion so that the rotor can be displaced in the axial direction with the rotor sandwiched from both the axial sides on the outer side and the inner side. Yes.
Further, the pressing piece is a member corresponding to a piston of a general disc brake device, and can be displaced in the axial direction in a cylinder space provided in a portion facing at least one of the two pads. Is provided.
The electric actuator presses the pads against both axial sides of the rotor by displacing the pressing piece in the direction of pushing out the cylinder space using an electric motor as a drive source.

In particular, in the electric disc brake device of the present invention, the electric actuator includes, in addition to the electric motor, a pressing unit, a spring, and a boosting unit that are arranged concentrically in the cylinder space. And a boost ratio conversion unit.
Of these, the electric motor rotates the output shaft in both directions based on energization.
Further, the pressing unit is displaced in a direction protruding from the cylinder space based on the rotation of the output shaft, and presses the pad facing the opening of the cylinder space against the axial side surface of the rotor.
The spring has one end in the axial direction abutting on a fixed portion on the inner surface of the cylinder space, and the other end in the axial direction is displaced in a direction in which the constituent member of the pressing unit protrudes from the cylinder space. The output unit applies a direction force.

The boosting unit includes a plurality of levers and fulcrum members, and a support plate member.
Each of these levers is intermittently arranged in the circumferential direction, and swings and displaces with each circumferential intermediate portion as a fulcrum.
Each fulcrum member is in contact with a circumferential intermediate portion of each lever.
The support plate member supports the fulcrum members on the side opposite to the levers in the axial direction.
Further, one end in the circumferential direction of each lever is engaged with a member to be pressed pressed by the output portion of the spring, and the other end is engaged with a part of the constituent members of the pressing unit so as to be able to swing and displace. ing.
Then, the pressing unit is displaced in a direction protruding from the cylinder space with the swing displacement of each lever based on the elasticity of the spring.

Further, the force increase ratio conversion unit displaces each fulcrum member in the circumferential direction of each lever, and displaces the pressing unit in a direction protruding from the cylinder space based on the elasticity of the spring and the elasticity. Change the boost ratio, which is the ratio with the magnitude of the force.
That is, the boost ratio conversion unit displaces each fulcrum member in the circumferential direction of each lever so that the distance between each fulcrum member and one circumferential end on the input side of each lever, and each fulcrum The ratio between the member and the distance between the other end in the circumferential direction on the output side of each lever is changed.

When the electric disc brake device of the present invention as described above is implemented, specifically, as in the invention described in claim 2, a locking plate is provided on the inner side of the cylinder space near the opening. Support in a state where displacement in the direction of exiting the cylinder space is prevented.
In addition, an anchor plate, which is a member to be pressed by the booster unit, is provided at an intermediate portion in the axial direction of the cylinder space while being prevented from rotating in the cylinder space and capable of axial displacement.
And the disc spring which is the said spring is clamped between the said latching plate and the said anchor plate.

Alternatively, as in the invention described in claim 3, each of the fulcrum members is a cylindrical roller, and each of the rollers is held in a plurality of pockets provided in a radial direction in the cage so as to be able to roll.
Moreover, let the part which the circumferential surface of each said roller contact | abuts among each said lever be a planar support surface.
And these each roller is provided between this bearing surface and the axial direction single side | surface of the support plate part which comprises the said boost ratio conversion unit.
Furthermore, the support plate portion is rotatably supported at the back end portion of the cylinder space by a thrust bearing provided between the other axial surface and the back end surface of the cylinder space.

Alternatively, as in the invention described in claim 4, the pressing unit includes an adjusting screw, an adjusting nut, and a pressing plate.
Among these adjustment screws, the distal end portion is engaged with the proximal end side surface of the pressing piece, and the intermediate portion to the proximal end portion are male screw portions. In the cylinder space, axial displacement is provided in a state where rotation is prevented.
Further, the adjustment nut is provided with a screw hole to be screwed with the male screw portion in the center portion and an outward flange-like flange portion on the outer peripheral surface of the tip portion.
Further, the pressing plate is annular, and a circumferential end of each lever is brought into contact with a plurality of circumferential locations on one axial side which is the back end surface side of the cylinder space among both axial side surfaces. The inner peripheral edge of the other surface in the axial direction is engaged with the flange. And the force of the direction which protrudes from the said cylinder space added with the rocking | fluctuation displacement of each said lever can be transmitted to the said adjustment nut.

Further, when the invention described in claim 3 and the invention described in claim 4 are simultaneously performed, preferably, as in the invention described in claim 5, the output shaft of the electric motor and the support are supported. A planetary gear speed reducer is provided between the plate portion and the adjusting nut.
And the sun gear of this planetary gear type reduction gear is rotationally driven by the output shaft.
Similarly, the support plate portion is rotationally driven by a ring gear.
Further, the adjustment nut is rotationally driven by a carrier that supports a plurality of planetary gears meshed with the sun gear and the ring gear.

When carrying out the invention described in claim 5, it is preferable to provide resistance means for providing resistance against the rotation of the ring gear as in the invention described in claim 6.
And, in the process of generating the braking force by sandwiching the rotor by the two pads based on the energization to the electric motor, the pressing surfaces of the two pads are based on the resistance applied to the ring gear by the resistance means. The carrier is rotated without rotating the ring gear with the rotation of the sun gear until the gap between the two sides of the rotor in the axial direction is eliminated.
Then, after the clearance is eliminated and the pressing surfaces of the pads are pressed against both axial sides of the rotor, the ring gear is rotated.

Further, when the invention described in claim 2 and the invention described in claim 4 are simultaneously performed, preferably, the locking plate and the adjusting nut are provided as in the invention described in claim 7. An elastic member such as a compression coil spring or a leaf spring is provided between the flange portion. Then, the adjustment nut is prevented from rattling in the cylinder space when the electric disk brake device is not braked.
When the invention described in claim 7 is carried out, preferably, as in the invention described in claim 8, one member of the locking plate and the flange portion of the adjustment nut One end portion of the elastic member is abutted, and a thrust bearing is provided in a portion between the other member and the other end portion of the elastic member. As such a thrust bearing, for example, a sliding bearing made of a metal material such as a synthetic resin or a metal containing a low friction coefficient, or a thrust rolling bearing can be used. In addition, a lubricant such as grease can be interposed between the aforementioned portions.

  In the electric disc brake device according to the present invention configured as described above, the force for pressing the linings of the two pads against the both side surfaces of the rotor to generate the braking force is the spring elasticity, each of which is centered on the fulcrum member. It is generated by transmitting to a constituent member of the pressing unit by a plurality of levers that swing and displace as follows. Such an electric disc brake device of the present invention operates as follows, and presses the lining of a pair of pads against both side surfaces of the rotor to perform braking.

  When the pressing unit is displaced in a direction protruding from the cylinder space based on energization of the electric motor in order to generate a braking force, a gap exists between the linings of the pads and both side surfaces of the rotor. During this time, the pressing unit quickly displaces in the direction protruding from the cylinder space without causing the booster unit and the booster ratio exchange unit to function. For this reason, the said clearance gap can be eliminated quickly and responsiveness can be ensured. That is, it is not necessary to operate the booster unit including the levers until the clearance is eliminated, and the moving speed of the pressing unit can be increased regardless of the boost ratio of the booster unit.

  After the clearance is eliminated, the fulcrum member is moved by the action of the boost ratio conversion unit, and the boost ratio of the boost unit including the levers can be increased. For this purpose, the pressing unit is pressed in a direction protruding from the cylinder space with a force sufficiently larger than the elasticity of the spring. As a result, it is possible to obtain a sufficient braking force by pressing the linings of the two pads against both side surfaces of the rotor with a sufficiently large force.

Further, the pressing unit, the spring, the boosting unit, and the boosting ratio conversion unit that constitute the electric actuator can be arranged coaxially by configuring each of them in an annular shape or a cylindrical shape. Therefore, the electric actuator can be made compact.
As a result, according to the present invention, the time required to generate the braking force can be shortened, and the generated braking force can be increased, and the electric disk brake device having a practical size as a vehicle braking device. Can be realized.

  According to the seventh aspect of the present invention, it is possible to prevent the adjusting nut constituting the pressing unit from rattling in the cylinder space when the electric disk brake device is not braked. For this reason, at the time of non-braking, it is possible to prevent a collision noise from occurring between the screw hole of the adjusting nut and the male screw portion of the adjusting screw, or damage such as wear to both the members.

Sectional drawing which shows the 1st example of embodiment of this invention. The exploded perspective view which takes out and shows an internal mechanism. The perspective view shown in the state which assembled the booster unit and the boost ratio conversion unit. The arrow X figure of FIG. 3 which abbreviate | omits a support plate member and shows in a state (A) with a small increase ratio and a large state (B). The schematic diagram which shows the change condition of the force increase ratio accompanying the displacement of the roller which is a fulcrum member. The diagram which shows the relationship between control input torque and pressing axial force with the structure of embodiment of this invention, and the conventional structure. The expanded sectional view equivalent to the Y section of Drawing 1 showing the 2nd example of an embodiment of the invention. Sectional drawing which shows an example of a conventional structure.

[First example of embodiment]
FIGS. 1-5 has shown the 1st example of embodiment of this invention corresponding to Claims 1-6. The electric disc brake device of this example is characterized by an output shaft 9a of an electric motor 8a constituting an electric actuator and a pressing piece 19 that presses the inner pad 2 toward the rotor 1 (see FIG. 8). It is in the point which provided the press unit 20, the plate spring 21 which is the spring described in the claim, the booster unit 22, and the boost ratio conversion unit 23 among them. In the case of this example, by adopting a configuration having such characteristics, the structure can be made compact. At the start of braking, the linings 18 and 18 of the both sides of the rotor 1 and the inner and outer pads 2 and 3 are provided. The gap between the two friction surfaces is quickly filled, and then the friction surfaces of both the linings 18 and 18 are strongly pressed against both side surfaces of the rotor 1 to realize a structure capable of generating a large braking force. Since the structure and operation of the other parts are the same as those conventionally known, including the structure shown in FIG. 8, the overlapping description will be omitted or simplified. The description will focus on the characteristic part. In the following description of the embodiment, the left end side in FIGS. 1 to 3, which is the end closer to the rotor 1, is the front end, and the right end in FIGS.

  In the case of this example, the inner surface of the cylinder space 6a provided in the caliper 4a is covered with a holding case 24, and the inside of the holding case 24 is sequentially claimed from the back side (base end side) of the cylinder space 6a. A thrust needle bearing 25 which is a thrust bearing described in the above-mentioned range, a boost ratio converting sleeve 27 provided with a support plate portion 26, and a plurality (three in the illustrated example) of rollers 28 each serving as a fulcrum member, 28, the same number of levers 29, 29 as the rollers 28, 28, a pressing plate 30, an adjusting nut 31, an anchor plate 32 which is a pressed member described in the claims, and the disc spring 21 The locking plate 33 and the adjustment screw 34 are assembled. The pressing piece 19 is installed in the opening of the cylinder space 6a so as to be capable of axial displacement. Based on the rotation of the output shaft 9a of the electric motor 8a, the pressing piece 19 is displaced in the axial direction to enable braking and release thereof. The pressing piece 19 is a member corresponding to a piston of a general disc brake device. However, in this example, the outer diameter of the pressing piece 19 is made sufficiently smaller than the inner diameter of the cylinder space 6a. In the case of this example, the pressing piece 19 is prevented from rotating through an adjusting screw 34 described below.

The pressing unit 20 includes the adjusting screw 34, the adjusting nut 31, and the pressing plate 30.
Of these, the adjusting screw 34 engages a conical portion 35 having a truncated cone-shaped head portion 35 provided at the distal end portion thereof, which is provided on the proximal end side surface of the pressing piece 19 and whose inner half is a partial conical concave shape ( The conical convex surface and the conical concave surface are brought into close contact with each other, and the retaining ring 37 prevents the conical convex surface and the conical concave surface from coming off. In this state, the adjusting screw 34 and the pressing piece 19 are combined so as to be concentric with each other and inadvertently rotate relatively. An intermediate portion or a base end portion of the adjustment screw 34 is a male screw portion 38.

The adjusting nut 31 is provided with a screw hole 39 that engages with the male screw portion 38 of the adjusting screw 34 at the center, and an outward flange-like flange 40 on the outer peripheral surface of the tip portion.
Further, the pressing plate 30 is formed of a metal plate having sufficient strength and rigidity and is formed into a substantially clover shape (substantially screw propeller shape) as a whole. Notch portions 42, 42 each having a substantially U-shape are provided at a plurality of intervals. The inner diameter of the circular hole 41 is slightly larger than the outer diameter of the portion of the adjustment nut 31 excluding the flange 40, and is sufficiently smaller than the outer diameter of the flange 40.

In order to constitute the pressing unit 20, the male screw portion 38 of the adjusting screw 34 is screwed into the screw hole 39 of the adjusting nut 31, and the pressing plate 30 is fitted on the adjusting nut 31. The distal end side surface of 30 and the proximal end side surface of the flange 40 are brought into contact with each other. In this state, the pressing unit 20 is configured to transmit the displacement of the pressing plate 30 in the distal direction to the pressing piece 19 via the adjusting nut 31 and the adjusting screw 34. The base end portion of the adjustment nut 31 is held at the central portion of the boost ratio converting sleeve 27 so as to be able to rotate and slightly displace in the axial direction.
Then, the elastic force of the disc spring 21 is transmitted to the pressing plate 30 via the booster unit 22, and the pressing piece 19 is pressed toward the rotor 1 based on the elastic force of the disc spring 21. I have to.

  The disc spring 21 is elastically compressed in the axial direction between the anchor plate 32 and the locking plate 33 and has a repulsive force (elasticity, thrust) required to obtain a braking force to be described later. Force). For this reason, the locking plate 33 is supported inside the end of the holding case 24 near the opening while preventing displacement in the direction of coming out of the holding case 24 (the direction toward the front end side). The supporting strength of the locking plate 33 with respect to the holding case 24 is sufficiently larger than the maximum value of the elasticity of the disc spring 21 so that the locking plate 33 does not come out of the holding case 24. Like. For this purpose, in a state in which each part to be stored in the holding case 24 is stored, the locking plate 33 is welded to the holding case 24 by means such as welding or caulking, etc. , Fix it. Further, in the illustrated example, a protrusion 44 is formed on the inner peripheral surface of the center hole 43 provided for inserting the adjustment screw 34, and the protrusion 44 and a part of the adjustment screw 34 are axially formed. The formed guide concave groove (not shown) is engaged to prevent the adjustment screw 34 from rotating. With the above configuration, the anchor plate 32 is elastically pressed toward the base end side (the back side of the holding case 24) by the elastic force of the disc spring 21. The holding case 24 is internally fitted and fixed in the cylinder space 6a by an interference fit in a state where the respective parts are accommodated. Further, if necessary, a retaining ring formed on the inner peripheral surface of the opening of the cylinder space 6a is used to prevent the cylinder space 6a from coming off.

  The booster unit 22 includes the anchor plate 32, the levers 29 and 29, the rollers 28 and 28, and a support plate portion 26 of the boost ratio conversion sleeve 27. Then, the elastic force applied to the anchor plate 32 as described above is increased at least at the final stage of the braking operation and then transmitted to the pressing plate 30, and the pressing plate 30 is transmitted to the tip side (from the holding case 24). Press in the direction of exit). The anchor plate 32 is provided with anchor projections 46 and 46 each having a substantially U-shape at a plurality of circumferentially equidistant positions (three locations in the illustrated example) on the inner peripheral surface of the cylindrical holding tube portion 45. The locking protrusions 47, 47 that are long in the axial direction are respectively formed at a plurality of circumferentially equidistant positions (three in the illustrated example). The anchor protrusions 46 and 46 engage with the notches 42 and 42 of the pressing plate 30 without rattling and allow the axial displacement of the pressing plate 30 to be allowed. The locking protrusions 47, 47 are formed at a plurality of equally spaced circumferential locations (three locations in the illustrated example) of the holding case 24, each having a locking notch 48, 48 each having a slit shape. Is engaged. Therefore, the anchor plate 32 is held in the holding case 24 so as to be axially displaceable based on the elasticity of the disc leaf spring 21 while being prevented from rotating.

  The levers 29 and 29 are provided in the same number as the anchor protrusions 46 and 46 (three in the illustrated example), and each has a thickness sufficient to ensure sufficient strength and rigidity. The shape seen from the axial direction is a partial arc shape. Further, at one end in the circumferential direction of the tip side surface of each of the levers 29, 29, each is a partially spherical convex surface and formed with protrusions 49, 49 serving as swing fulcrums. Further, holding concave portions 50 and 50 each having a partial spherical concave surface are formed at the other circumferential end portion of the tip side surface. The protrusions 49 and 49 are brought into contact with the base end surfaces of the anchor protrusions 46 and 46 of the anchor plate 32. Further, the front end portions of the balls 51 and 51, which are in contact with the inner surfaces of the holding recesses 50 and 50, are in contact with the receiving recesses 52 formed on the base end side surface of the pressing plate 30. I am letting.

  Furthermore, the front end side end portions of the rolling surfaces of the rollers 28 and 28 are brought into contact (rolling contact) with the circumferential intermediate portions of the base end side surfaces of the levers 29 and 29, respectively. These rollers 28 and 28 are arranged in the radial direction in a state in which they are rotatably held in the pockets of the cage 53. In this state, the base end side end portion of the rolling surface of each of the rollers 28 and 28 is brought into rolling contact with the front end side surface of the support plate portion 26. The levers 29 and 29 swing and displace with the rollers 28 and 28 as fulcrums, and elastic force (thrust force) input from the disc spring 21 via the anchor plate 32 is applied to the pressing plate 30. The pressure plate 30 is transmitted to the front end side. The thrust force applied to the pressing plate 30 causes the rollers 28, 28 to roll in the circumferential direction along the levers 29, 29, and serves as swinging fulcrums for the levers 29, 29. It can be changed by changing the circumferential positions of 28 and 28. Note that, regardless of the position of the rollers 28, 28, the rolling surfaces of the rollers 28, 28, the proximal side surfaces of the levers 29, 29, and the distal side surface of the support plate portion 26 In order to prevent an excessive surface pressure based on the edge load from acting on the contact portion, appropriate rolling is applied to the rolling surfaces of the rollers 28 and 28. Alternatively, spherical rollers can be used as the rollers 28 and 28.

  The force increase ratio conversion unit 23 is for changing the circumferential position of the rollers 28 and 28 with respect to the levers 29 and 29 in synchronization. In addition to the rollers 28 and 28 and the retainer 53, The thrust needle bearing 25 and the boost ratio converting sleeve 27 are provided. The force increase ratio conversion sleeve 27 is formed with a support cylindrical portion 54 on the inner peripheral edge of the support plate portion 26 in the shape of a ring so as to protrude toward the base end side. The support plate portion 26 is abutted against an annular end plate 55 constituting the holding case 24 via the thrust needle bearing 25. The support cylindrical portion 54 is inserted through an inner diameter side of the back end plate 55 and a circular through hole 57 formed in the back end wall 56 of the caliper 4a. And the base end part of the said support cylindrical part 54 is protruded from the base end surface of the said caliper 4a.

  The force increase ratio conversion unit 23 rotates the force increase ratio conversion sleeve 27 to rotate the rollers 28 and 28 between the support plate portion 26 and the base end side surfaces of the levers 29 and 29. Move. For example, as shown in FIGS. 3, 4, and 5 (A), the rollers 28, 28 are positioned on the side close to the protrusions 49, 49 at one end in the circumferential direction of the levers 29, 29. As a result, the force increase ratio by each of the levers 29 and 29 becomes small (a value less than 1). On the other hand, with the rotation of the support plate portion 26, the rollers 28, 28 are moved closer to the portion provided with the balls 51, 51 at the other circumferential end of the levers 29, 29. When positioned, the force increase ratio by the levers 29 and 29 increases. And the thrust force which presses the said adjustment nut 31 by the said press board 30 based on the elasticity of the said disk spring 21 becomes large because this force increase ratio becomes large.

  In the case of this example, the output shaft 9a of the electric motor 8a further rotationally drives the adjusting nut 31 of the pressing unit 20 and the speed increasing ratio converting sleeve 27 of the speed increasing ratio converting unit 23 described above. For this purpose, a planetary gear type transmission 58 is provided between these members 9a, 31 and 27. The planetary gear type transmission 58 includes a sun gear 59 and a ring gear 60 arranged concentrically with each other, and a plurality of planetary gears 61 and 61. Each of the planetary gears 61 and 61 is rotatably supported by the carrier 62 in a state where the planetary gears 61 and 61 are arranged at equal intervals in the circumferential direction between the sun gear 59 and the ring gear 60. 59 and the ring gear 60 are engaged.

The sun gear 59 can be rotationally driven via the power transmission mechanism 63 by the output shaft 9a of the electric motor 8a. As the power transmission mechanism 63, a general belt transmission mechanism or a gear transmission mechanism can be adopted. Further, a coupling cylinder portion 64 provided concentrically with the ring gear 60 is provided at the distal end portion of the ring gear 60 on the outer peripheral surface of the base end portion of the support cylindrical portion 54 so that torque can be transmitted by serration engagement or the like. It is fitted. As the ring gear 60 rotates, the boost ratio conversion sleeve 27 can be driven to rotate.
Further, a center shaft 65 projecting from the front end side center portion of the carrier 62 is serrated to a serration hole 66 provided at the proximal end portion of the adjustment nut 31. The adjustment nut 31 can be rotationally driven by the carrier 62.

  Further, a resistance means 67 is provided in a state facing the outer peripheral surface of the ring gear 60. The resistance means 67 gives resistance against the rotation of the ring gear 60. For example, a friction resistance member such as a spring element or a friction pad can be used. The resistance applied to the ring gear 60 by the resistance means 67 prevents the rotation of the ring gear 60 while the torque required to rotationally drive the adjustment nut 31 by the carrier 62 is small. When the torque increases, the ring gear 60 is allowed to rotate.

  Specifically, based on energization to the electric motor 8a, in the process of holding the rotor 1 by the two pads 2 and 3 and generating a braking force, the adjusting nut 31 is rotated, and the adjusting screw 34 is moved. By pushing out from the adjusting nut 31, the rotation of the ring gear 60 is prevented until the linings 18, 18 of the pads 2, 3 are pressed against both side surfaces of the rotor 1. On the other hand, the linings 18 and 18 of the pads 2 and 3 are pressed against both side surfaces of the rotor 1, and the torque required to rotate the adjusting nut 31 to push out the adjusting screw 34 is increased. In this case, the ring gear 60 is allowed to rotate.

The electric disc brake device of this example configured as described above operates as follows, and presses the linings 18 and 18 of both the pads 2 and 3 against both side surfaces of the rotor 1 to perform braking.
During non-braking, there is a gap between the linings 18 and 18 of the pads 2 and 3 and both side surfaces in the axial direction of the rotor 1. From this state, the electric motor 8a is energized to perform braking, and the sun gear 59 of the planetary gear type transmission 58 is rotated in a predetermined direction via the power transmission mechanism 63. In this state, the ring gear 60 constituting the planetary gear type transmission 58 does not rotate based on the resistance applied by the resistance means 67. As a result, the planetary gears 61 and 61 meshed with the ring gear 60 and the sun gear 59 revolve around the sun gear 59 while rotating. Of these, the revolving motion is transmitted to the adjustment nut 31 via the carrier 62, and the adjustment nut 31 rotates in a predetermined direction. Along with this rotation, the adjustment screw 34 is displaced in the direction of being pushed out from the cylinder space 6 a based on the screw engagement between the male screw portion 38 and the screw hole 39. As a result, the inner pad 2 is pressed against the inner side surface of the rotor 1 by the pressing piece 19, and the caliper 4 a is displaced toward the inner side, and the caliper claw 5 causes the outer pad 3 to be moved to the outer side of the rotor 1. Press against the side.

  In this manner, the boosting unit 22 and the boost ratio conversion unit 23 do not particularly function while the clearance between the linings 18 and 18 and both axial side surfaces of the rotor 1 is eliminated. That is, in the process of eliminating the gap, the rollers 28, 28 are connected to the protrusions 49, 49 at one end in the circumferential direction of the levers 29, 29, as shown in FIGS. It remains in the state that exists in the vicinity of. For this reason, these levers 29 and 29 do not increase the elasticity of the disc spring 21 and transmit it to the pressing plate 30. The speed at which the clearance is eliminated is determined by the reduction ratio of the power transmission mechanism 63 and the planetary gear mechanism 58 and the lead angles of the male screw portion 38 and the screw hole 39. Since the force required to eliminate the gap is small, there is no need to particularly increase the reduction ratio or particularly reduce the lead angle. As a result, the gap can be quickly eliminated and responsiveness can be improved.

  When the clearance is eliminated, the torque required to rotate the adjustment nut 31 to push the adjustment screw 34 out of the cylinder space 6a increases. As the torque increases, the rotational speed of the carrier 62 gradually decreases, and eventually the carrier 62 does not rotate. Then, the rotation of the sun gear 59 is transmitted to the ring gear 60 through the planetary gears 61, 61, and the ring gear 60 starts to rotate against the resistance by the resistance means 67. The ring gear 60 rotates the boost ratio conversion sleeve 27 in a predetermined direction (counterclockwise in FIG. 4).

  As the force increase ratio conversion sleeve 27 rotates, the rollers 28, 28 move between the front end side surface of the support plate portion 26 of the force increase ratio conversion sleeve 27 and the base end side surfaces of the levers 29, 29. Roll on. Then, from the state shown in FIGS. 4 and 5 (A), through the state shown in FIGS. 4 and 5 (B), the balls 51, It moves toward the part which 51 contact | abutted. When these levers 29, 29 transmit the elasticity of the disc spring 21 to the pressing plate 30, the degree to which this elasticity increases is determined by the rolling surfaces of the rollers 28, 28 and the levers 29, 28. 29 becomes larger as the input side span becomes longer, which is the distance between the contact portion with the base end side surface of 29 and the projections 49, 49 on the input side of the levers 29, 29. Further, the abutting portions between the rolling surfaces of the rollers 28 and 28 and the base end side surfaces of the levers 29 and 29, and the holding recesses 50 and 50 on the output side of the levers 29 and 29, The output side span, which is the distance from the center of the contact portion with each of the balls 51, 51, becomes larger as the length becomes shorter.

  As described above, as the force increase ratio converting sleeve 27 rotates, the rollers 28, 28 move toward the other circumferential end of the levers 29, 29, so that the input side span is increased. Is longer and the output-side span is shorter. The elasticity of the disc spring 21 is transmitted to the pressing plate 30 along with the swinging displacement of the levers 29, 29 with the rollers 28, 28 as fulcrums. The inner pad 2 is pressed against the inner side surface of the rotor 1 through the nut 31, the adjustment screw 34, and the pressing piece 19. In this state, the force increasing ratio of the force increasing unit 22 increases as the rollers 28 and 28 roll. Therefore, the force by which the pressing piece 19 presses the inner pad 2 against the inner surface in the axial direction of the rotor 1 can be sufficiently increased, and a sufficient braking force can be obtained.

  When releasing the brake, the sun gear 59 is rotated in the direction opposite to the predetermined direction based on the energization of the electric motor 8a. Then, each part is displaced in the direction opposite to that at the time of braking described above, and the pressing piece 19 is retracted from the rotor 1. As a result, gaps exist between the linings 18 and 18 of the pads 2 and 3 and both side surfaces of the rotor 1 in the axial direction.

  In the case of the electric actuator of the present example configured as described above and acting as described above, the pressing unit 20, the disc spring 21, the booster unit 22, and the boost ratio conversion unit 23 Can be arranged on the same axis by forming each of them into a ring shape or a cylindrical shape. Then, those parts assembled in the holding case 24 (sub-assembled state) can be assembled in the cylinder space 6a of the carrier 4a. Therefore, the electric actuator can be configured in a small size and can be easily assembled.

  Further, at the start of braking, until the clearance between the linings 18 and 18 of both the pads 2 and 3 and the both side surfaces in the axial direction of the rotor 1 is eliminated, the boosting unit 22 and the boosting ratio conversion unit 23 are used. These boosting units 22 and the boosting ratio conversion unit 23 are operated only in the final stage in which a large braking force is generated without operating. For this reason, the time required to generate the braking force can be shortened. Further, a sufficiently large braking force can be obtained without particularly increasing the output of the electric motor 8a. For example, in the case of an electric disc brake device using a simple actuator, as shown by a broken line α in FIG. 6, in order to obtain a large pressing force to obtain a large braking force, the output torque of the electric motor It was necessary to increase (control input torque). On the other hand, according to the structure of this example, as shown by the solid line β in FIG. 6, a large pressing axial force can be obtained even with a relatively small control input torque. That is, the pressing axial force begins to increase after the control input torque has increased to some extent by the provision of the resistance means 67, but when it starts to increase, the pressing axial force increases rapidly, so that the required pressing axial force can be obtained. The control input torque required for this can be kept low.

[Second Example of Embodiment]
FIG. 7 shows a second example of an embodiment of the present invention corresponding to claims 1 to 8. In the case of this example, in order to prevent the adjustment nut 31 from rattling in the cylinder space 6a (see FIG. 1) when the electric disc brake device is not braked, the flange 40 of the adjustment nut 31 and the locking plate 33a In between, the compression coil spring 68 which is the elastic member described in the claim is provided. For this purpose, a step portion 69 is provided near the inner diameter portion of the locking plate 33a, and one end portion (left end portion in FIG. 7) of the compression coil spring 68 is abutted against the step portion 69. Further, an annular thrust bearing 70 is provided between the other end portion (the right end portion in FIG. 7) of the compression coil spring 68 and the flange portion 40. As such a thrust bearing 70, a sliding bearing made of a synthetic resin material having a low friction coefficient such as polyamide resin or polytetrafluoroethylene resin, or a metal material having a low friction coefficient such as a contained metal or a copper-based alloy is used. Can be used. Alternatively, a thrust rolling bearing such as a thrust needle bearing can be used as the thrust bearing 70.

In the case of this example, since the compression coil spring 68 elastically presses the adjustment nut 31 toward the base end side, it is possible to prevent the adjustment nut 31 from rattling in the cylinder space 6a during non-braking. . As a result, it is possible to prevent a collision sound from being generated between the screw hole 39 of the adjustment nut 31 and the male screw portion 38 of the adjustment screw 34, and damage such as wear to the both members 31 and 34. Note that the pressing force by the compression coil spring 68 is made as small as possible to prevent rattling of the adjustment nut 31 during non-braking.
In the case of the structure of this example, the coefficient of friction between the two members 68 and 31 is kept low between the other end of the compression coil spring 68 and the flange 40 of the adjustment nut 31. For this purpose, a thrust bearing 70 is provided. For this reason, at the time of braking (when the adjusting nut 31 is rotated), a large power loss does not occur based on the frictional resistance between the members 68 and 31. As a result, it is possible to prevent the time required for generating the braking force from increasing and the power consumption of the electric motor 8a (see FIG. 1) from increasing. Instead of providing the thrust bearing 70, a lubricant such as grease may be interposed between the other end portion of the compression coil spring 68 and the flange portion 40 of the adjustment nut 31.
Since the configuration and operation of the other parts are the same as in the first example of the embodiment described above, overlapping illustrations and descriptions are omitted.

  The structure of the present invention is such that the electric motor can be shared among a plurality of pressing pieces, but a booster unit, a boost ratio conversion unit, etc. are required for each pressing piece, etc. Compared to the device, the volume of the device portion that drives the pressing piece increases. Therefore, it is preferable to use a floating caliper type disc brake that requires only a small number of pressing pieces and can easily secure a space for the pressing piece installation portion. However, if it is possible to secure an installation space, such as for a large automobile, it is possible to use an opposed piston type disc brake.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Inner pad 3 Outer pad 4, 4a Caliper 5 Caliper claw 6, 6a Cylinder space 7 Thrust generator 8, 8a Electric motor 9, 9a Output shaft 10 Reducer 11 Piston 12 Feed screw device 13 Drive side rotor 14 Drive side lamp Groove 15 Driven-side stator 16 Driven-side ramp groove 17 Ball 18 Lining 19 Pressing piece 20 Pressing unit 21 Belleville spring 22 Booster unit 23 Booster ratio conversion unit 24 Holding case 25 Thrust needle bearing 26 Support plate part 27 For booster ratio conversion Sleeve 28 Roller 29 Lever 30 Press plate 31 Adjustment nut 32 Anchor plate 33, 33a Locking plate 34 Adjustment screw 35 Head portion 36 Recessed portion 37 Retaining ring 38 Male thread portion 39 Screw hole 40 Groove portion 41 Circular hole 42 Notch portion 43 Center Hole 44 Protrusion 45 Holding cylinder portion 46 Anchor protrusion 47 Locking protrusion 48 Locking notch 49 Protrusion 50 Holding recess 51 Ball 52 Receiving recess 53 Cage 54 Support cylindrical portion 55 Back end plate 56 Back end wall 57 Through Hole 58 Planetary gear type transmission 59 Sun gear 60 Ring gear 61 Planetary gear 62 Carrier 63 Power transmission mechanism 64 Coupling cylinder portion 65 Center shaft 66 Serration hole 67 Resistance means 68 Compression coil spring 69 Stepped portion 70 Thrust bearing

Claims (8)

A rotor that rotates with the wheel, a pad support that is supported by the vehicle body in a state adjacent to the rotor, and a pad support that is axially displaceable with the rotor sandwiched from both sides in the axial direction. A pair of pads on the outer side and the inner side, a pressing piece provided in a cylinder space provided in a portion facing at least one of these pads, and capable of axial displacement; In an electric disc brake device including an electric actuator that presses the two pads against both axial sides of the rotor by displacing the pressing piece in the direction of pushing out the cylinder space using a motor as a drive source,
In addition to the electric motor, the electric actuator includes a pressing unit, a spring, a boosting unit, and a boosting ratio conversion unit that are arranged concentrically in the cylinder space.
Of these, the electric motor rotates the output shaft in both directions based on energization,
The pressing unit is displaced in a direction protruding from the cylinder space based on the rotation of the output shaft, and presses the pad opposed to the opening of the cylinder space against the axial side surface of the rotor,
The spring is configured so that one end of the axial direction is brought into contact with a fixed portion on the inner surface of the cylinder space, and the other end of the axial direction is displaced in a direction of projecting the constituent member of the pressing unit from the cylinder space. It is an output part that gives power,
The boosting unit is intermittently arranged in the circumferential direction, and a plurality of levers that swing and displace with each circumferential intermediate portion as a fulcrum, and fulcrum members that respectively contact the circumferential intermediate portions of these levers, A support plate member that supports each of these fulcrum members on the opposite side of each of these levers in the axial direction, and a circumferentially one end of each of these levers is pressed against the pressed member that is pressed by the output portion of the spring Similarly, the other end is engaged with a part of the constituent member of the pressing unit so as to be able to swing and displace, and the pressing unit is moved to the cylinder according to the swinging displacement of each lever based on the elasticity of the spring. It is displaced in the direction protruding from the space,
The force increase ratio conversion unit displaces each fulcrum member in the circumferential direction of each lever, and the distance between each fulcrum member and one circumferential end on the input side of each lever, and each fulcrum member; The elastic force of the spring, which is determined by the ratio of the distance from the other end in the circumferential direction on the output side of each lever, and the magnitude of the force that displaces the pressing unit in the direction of protruding from the cylinder space based on the elastic force. The electric disc brake device is characterized by changing the power increase ratio, which is a ratio of A locking plate is supported on the inner side of the cylinder space near the opening, in a state where displacement in the direction of exiting from the cylinder space is prevented,
An anchor plate, which is a pressed member of the booster unit, is provided in the axially intermediate portion of the cylinder space so as to be capable of axial displacement while being prevented from rotating in the cylinder space.
The electric disc brake device according to claim 1, wherein a disc spring, which is the spring, is sandwiched between the locking plate and the anchor plate.   Each of the fulcrum members is a cylindrical roller, and each of these rollers is rotatably held in a plurality of pockets provided in the radial direction of the cage. The portion where the surface abuts is a flat support surface, and each of these rollers is provided between this support surface and one axial surface of the support plate portion constituting the force increase ratio conversion unit. The portion is supported at the back end of the cylinder space in a rotatable manner by a thrust bearing provided between the other axial surface and the back end surface of the cylinder space. The electric disc brake device described in item 1. The pressing unit includes an adjusting screw, an adjusting nut, and a pressing plate;
Of these, the adjusting screw has a distal end portion engaged with a proximal end side surface of the pressing piece and an intermediate portion or a proximal end portion as a male screw portion, and the shaft is rotated in the cylinder space while being prevented from rotating. It is provided to allow displacement in the direction,
The adjustment nut is provided with a screw hole that engages with the male screw portion at the center, and an outward flange-like flange on the outer peripheral surface of the tip portion, respectively.
The pressing plate is annular and has one end in the circumferential direction of each lever in contact with a plurality of positions in the circumferential direction on one side in the axial direction, which is the back end face side of the cylinder space, on both sides in the axial direction. The inner peripheral edge of the other surface is engaged with the flange, and the force in the direction protruding from the cylinder space, which is applied along with the swing displacement of each lever, can be transmitted to the adjustment nut. The electric disc brake device described in any one of 1 to 3.   A planetary gear speed reducer is provided between the output shaft of the electric motor and the support plate portion and the adjustment nut. The sun gear of the planetary gear speed reducer is driven to rotate by the output shaft, and the ring The reference plate according to claim 3, wherein the support plate portion is rotationally driven by a gear, and the adjustment nut is rotationally driven by a carrier that supports a plurality of planetary gears meshed with the sun gear and a ring gear. The electric disc brake device described in 1.   In the process of providing resistance against rotation of the ring gear and generating a braking force by sandwiching the rotor between the pads based on energization of the electric motor, the resistance means Based on the resistance applied to the gear, the ring gear is rotated with the rotation of the sun gear until the clearance between the pressing surfaces of the pads and the both axial sides of the rotor is eliminated. The electric disc brake according to claim 5, wherein the carrier is rotated without rotation, the ring gear is rotated after the clearance is eliminated and the pressing surfaces of the pads are pressed against both axial sides of the rotor. apparatus.   3. The reference cited in claim 2, wherein an elastic member is provided between the locking plate and the flange portion of the adjustment nut, and prevents the adjustment nut from rattling against the cylinder space during non-braking. 4. The electric disc brake device described in 4.   One end of the elastic member is abutted against one member of the locking plate and the flange portion of the adjustment nut, and similarly between the other member and the other end of the elastic member. The electric disc brake device according to claim 7, wherein a thrust bearing is provided.

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