JP2014214752A - Electric disc brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric disc brake device capable of obtaining large braking force while securing sufficient durability.SOLUTION: A thrust generating mechanism 8a for converting a torque of an electric motor into an axial thrust for pressing out a piston 12a from a cylinder space 7a, is composed of a feed screw mechanism 13a and a boosting mechanism 14a. In the booting mechanism 14a, a structure using a truncated cone-shaped taper roller 43 is substituted for a conventional ball-ramp type boosting mechanism using a ball. A cylindrical guide ring 44 is arranged around the taper roller 43 to bear a component force directing radially outward and acting on the taper roller 43.

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, an electric disc brake device capable of obtaining a large braking force while ensuring sufficient durability is realized.

  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. The research is being conducted because there are many advantages, such as the fact that used brake fluid is not generated and the environmental load is small, and the response is improved by the amount of movement of the brake fluid. 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 combining a gear-type reduction device and a ball / lamp type boosting mechanism have been proposed, for example, as described in Patent Documents 1 to 4. Has been.

  FIG. 9 shows an example of a conventional structure described in Patent Document 1 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 4 (see each figure showing an example of an embodiment of the present invention) is supported on the vehicle body (fixed to a knuckle constituting a 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). The support 4 is supported.

  A caliper 5 is assembled to the support 4 so as to be capable of axial displacement. The caliper 5 is provided with a caliper claw 6 at an outer side end portion and a cylinder space 7 inside an inner side portion. The caliper pawl 6 is opposed to 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 mechanism 8 provided in the cylinder space 7. 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 mechanism 8, the caliper 5 is displaced toward the inner side based on the pressure, and the caliper pawl 6 causes the outer pad 3 to move to the rotor. Press against the outer side of 1. 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 9 is used as a drive source to press the inner pad 2 against the inner side surface of the rotor 1, and the output shaft 10 of the electric motor 9 and the inner side surface of the inner pad 2. Are provided with a gear-type speed reducer 11, the thrust generating mechanism 8, and a piston 12. The rotational force that has been decelerated by the speed reducer 11 and increased in torque is transmitted to the ball-and-ramp type force-increasing mechanism 14 via the feed screw mechanism 13, and the drive-side rotor 15 that constitutes the force-increasing mechanism 14 Rotate. The drive-side rotor 15 is moved to the outer side by the function of the feed screw mechanism 13 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 mechanism 13 is stopped, it rotates. Then, a plurality of drive side ramp grooves 16, 16 provided on the outer side surface of the drive side rotor 15, and a plurality of driven sides provided on the inner side surface of the driven side stator 17 attached to the inner side surface of the piston 12. Based on the engagement (rolling contact) between the side lamp grooves 18 and 18 and a plurality of balls 19 sandwiched between the lamp grooves 16 and 18, the driving side rotor 15 and the driven side stator 17. Expand the distance between and with great force. As a result, the outer side surface of the piston 12 is strongly pressed against the inner side surface of the inner pad 2.

  In the case of the electric disc brake device provided with the ball-and-lamp type boosting mechanism 14 as described above, the number of balls 19 that can be used is limited (generally, three) due to restrictions on dimensions and the like, Since the contact state of the rolling contact portion between the rolling surface of each ball 19 and the lamp grooves 16 and 18 is close to point contact (the area of the contact ellipse existing in the rolling contact portion is small), the rolling contact portion Surface pressure increases. For this reason, in order to obtain a large braking force, when the thrust generated by the force-increasing mechanism 14 (pressing the inner pad 2) is increased by, for example, loosening the inclination angle of the ramp grooves 16, 18. A particularly large stress is generated at the bottom of each of the ramp grooves 16 and 18 in each of the rolling contact portions. As a result, the rolling fatigue life of each of the ramp grooves 16 and 18 may be reduced or, if remarkable, damage such as indentation may occur at the bottom of each of the ramp grooves 16 and 18. Thus, in the case of the electric disc brake device provided with the ball / lamp type boosting mechanism 14 having a conventional structure, it is difficult to obtain a large braking force while ensuring sufficient durability.

JP 2004-169729 A JP 2010-265971 A JP 2000-291702 A JP 2012-77809 A

  The present invention has been invented in order to realize an electric disc brake device capable of obtaining a large braking force while ensuring sufficient durability 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 piston, 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 two pads are supported by the pad support portion so as to be axially displaceable with the rotor sandwiched from both sides in the axial direction.
The piston is provided in a cylinder space provided in a portion facing at least one of the two pads so that the rotor can be displaced in the axial direction.
The electric actuator presses the two pads against both axial sides of the rotor by displacing the piston in the direction of pushing out the cylinder space.
The pad support portion includes a support when the electric disc brake device of the present invention is a floating caliper type disc brake, and a caliper when the opposed piston type disc brake is used. Correspond.

In particular, in the electric disc brake device of the present invention, the electric actuator is configured to convert an electric motor that rotates the output shaft in both directions based on energization, and to convert the rotational driving force of the electric motor into axial thrust. And a thrust generating mechanism having a feed screw mechanism and a force increasing mechanism for pushing out the piston from the cylinder space.
Of these, the feed screw mechanism has a male screw portion on the outer peripheral surface, and an adjuster screw that is rotationally driven by the electric motor and a female screw portion provided on the inner peripheral surface are screwed into the male screw portion, thereby adjusting the adjuster screw. And an adjuster sleeve that is displaceable in the axial direction as the screw rotates.
The boosting mechanism includes a driving rotor, a driven stator, a plurality of tapered rollers, and a guide ring.
Of these, the drive-side rotor is supported so as not to rotate relative to the adjuster sleeve, and on the drive side facing the piston, the height in the axial direction gradually changes in the same direction with respect to the circumferential direction. Has a ramp trajectory.
The driven-side stator has a plurality of driven side surfaces whose height in the axial direction gradually changes in a direction opposite to the driving-side ramp track in the circumferential direction on the driven side surface facing the driving side surface in the axial direction. It has a side ramp track, and is provided so that it can be displaced in the axial direction with respect to the piston and cannot rotate relative to the piston.
Further, each taper roller has a central axis in a diametrical direction (a small-diameter end on an inner diameter side and a large-diameter side end on a space between each driving-side lamp track and each driven-side lamp track. It is pinched so that it can roll in the state of being arranged on the outer diameter side.
Further, the guide ring is arranged around each taper roller, and a central portion of the outer end surface in the radial direction of each taper roller is brought into contact with an inner peripheral surface thereof, and is rotated along with the revolving motion of each taper roller. Is done.

When implementing the electric disc brake device of the present invention as described above, preferably, the driven side stator is connected to the adjuster sleeve in the axial direction as in the invention described in claim 2. It is externally supported so as to be relatively rotatable at the end near the rotor.
Further, when the electric disc brake device of the present invention is implemented, it is preferable that the driven side stator be engaged with the driven side stator so as not to rotate relative to the driven side stator as in the invention described in claim 3. The piston is engaged with the piston so as not to rotate relative to each other through a combined substantially circular ring-shaped detent plate.

According to the present invention configured as described above, it is possible to realize an electric disc brake device that can obtain a large braking force while ensuring sufficient durability.
That is, in the case of the present invention, a force-increasing mechanism using a taper roller is adopted as a force-increasing mechanism constituting the thrust generating mechanism, instead of the conventional ball / ramp-type force-increasing mechanism using a ball. For this reason, the contact state of the rolling contact portion between the rolling surface of the taper roller and each of the ramp tracks on the driving side and the driven side can be changed from point contact to line contact, and the surface pressure of the rolling contact portion can be kept low. . Therefore, in order to obtain a large braking force, for example, when the thrust generated by the force-increasing mechanism is increased by, for example, loosening the inclination angle of each of the driving side and driven side ramp tracks, a large stress is applied to each of these ramp tracks. Can be effectively prevented. As a result, according to the structure of the present invention, it is possible to realize an electric disc brake device that can obtain a large braking force while ensuring sufficient durability.

Each taper roller has a circumferential length that changes in accordance with an axial position (a radial position of the force-increasing mechanism), so that each ramp track on the driving side and the driven side is accompanied with the rotation of the driving side rotor. Can be prevented from slipping between the rolling surface of each taper roller and the driving side and driven side ramp tracks. Further, each of the taper rollers is subjected to a component force directed radially outward by being sandwiched between the drive side ramp track and the driven side ramp track. It can be supported by a guide ring arranged around each taper roller. For this reason, when the said drive side rotor rotates, the radial direction position of each said taper roller can be stabilized. Accordingly, each of these taper rollers can be smoothly rolled, and the efficiency (axial force conversion efficiency) for converting the rotational force of the drive-side rotor into thrust that is axial force can be increased.
In addition, since the drive-side rotor is formed separately from the adjuster sleeve, the drive-side rotor and the adjuster sleeve can be manufactured more easily than when the drive-side rotor is formed integrally. I can do things.

  In the case of the invention described in claim 2, when the force-increasing mechanism is operated, the driven-side stator that rotates relative to the driving-side rotor is moved relative to the adjuster sleeve that supports the driving-side rotor. Since the outer fitting is supported so as to be rotatable, the coaxiality of the driving side rotor and the driven side stator can be increased. Therefore, the operation at the time of braking can be performed stably.

  Further, in the case of the invention described in claim 3, the driven-side stator is made non-rotatable relative to the piston through a substantially annular detent plate separate from the driven-side stator. Since it is engaged, the degree of freedom regarding the shape of the driven-side stator other than the portion with which the detent plate is engaged can be increased. For this reason, in the driving side stator, the shape of the tip surface that contacts the back end surface of the piston is made into a convex curved surface shape or a partial conical convex shape, or the shape of the outer peripheral surface arranged on the inner diameter side of the guide ring, Design such as cylindrical surface becomes easy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an example of an electric disc brake device according to an embodiment of the present invention as seen from the outer side and radially outward. The orthographic view shown in the state similarly seen from the inner side. The orthographic view shown in the state similarly seen from radial direction outward. FIG. 3 is an orthographic projection view as seen from the left side of FIG. 2. AA sectional drawing of FIG. The B section enlarged view of FIG. CC sectional drawing of FIG. The disassembled perspective view which extracts and shows the piston and the thrust generation mechanism (excluding an adjustment task screw) arrange | positioned inside it. Sectional drawing which shows an example of a conventional structure.

[Example of Embodiment]
1 to 8 show an example of an embodiment of the present invention. The feature of this example is that the structure of the thrust generating mechanism 8a including the force-increasing mechanism 14a is devised in order to realize a structure that can obtain a large braking force while ensuring sufficient durability. Since the configuration and operation of the other parts are almost the same as those of the conventional structure shown in FIG. 9, the explanation for the equivalent parts will be omitted or simplified, and the characteristic part of this example and the explanation will be given below. The explanation will focus on the missing part.

  The electric disc brake device of this example is a floating caliper type, and is provided with a pair of guides on a support 4 provided in a state straddling a portion near the outer diameter of a rotor 1 (see FIG. 9) that rotates with a wheel (not shown). The caliper 5a is supported by the pins 20 and 20 so that the displacement of the rotor 1 in the axial direction is possible. Further, both ends of the inner pad 2 and the outer pad 3 are supported on the support 4 so as to be displaceable in the axial direction of the rotor 1, and the caliper 5 a is straddled across the inner and outer pads 2, 3. Is arranged.

  The electric actuator incorporated in the electric disc brake device of this example includes an electric motor 9a, a gear-type speed reducer 11a, and the thrust generating mechanism 8a. And by this electric motor 9a, the piston 12a fitted in the cylinder space 7a provided in the inner side part of the caliper 5a is directed toward the rotor 1 through the reduction gear 11a and the thrust generating mechanism 8a. By pushing out to the outer side and pressing the inner and outer pads 2 and 3 against both side surfaces of the rotor 1 in the axial direction, a braking force is generated.

  The piston 12a has a bottomed cylindrical shape, and has a distal end side (side closer to the rotor 1) closed with a bottom portion 21 and a proximal end side opened. A concave conical receiving surface 22 is formed on the inner surface of the bottom 21 near the outer diameter. Further, at the two positions opposite to the diameter direction of the cylindrical side wall portion 23 of the piston 12a, slits 24, 24 which are long in the axial direction are opened at the inner side end edges on the base end side of the piston 12a. Is forming. Further, in a state where such a piston 12a is fitted in the cylinder space 7a, a seal ring 25 is provided between the outer peripheral surface of the front end portion of the piston 12a and the inner peripheral surface of the opening edge portion on the outer side of the cylinder space 7a. Is provided.

  The electric motor 9a rotationally drives the output shaft in both directions based on energization. The gear type reduction gear 11a is formed by meshing a plurality of gears, and the reduction ratio is set to "16", for example. Therefore, the speed reducer 11a rotates the adjust screw 27 constituting the feed screw mechanism 13a described below once while the output shaft of the electric motor 9a rotates 16 times to increase the torque 16 times. In the case of this example, the electric motor 9a and the speed reducer 11a are accommodated in a casing 26 fixed to the inner side end of the caliper 5a with a plurality of bolts.

  The thrust generating mechanism 8a is for converting the rotational driving force of the electric motor 9a transmitted through the speed reducer 11a into an axial thrust and pushing the piston 12a out of the cylinder space 7a. The feed screw mechanism 13a and the force increasing mechanism 14a are provided in series with respect to the force transmission direction.

  Of these, the feed screw mechanism 13 a is composed of the adjustment task screw 27 and the adjuster sleeve 28. This adjust task screw 27 is provided with a male threaded portion 29 at the outer half of the outer peripheral surface, and an outward flange-shaped thrust receiving portion 30 that functions as one of the race rings of a thrust bearing 40 described later at the intermediate portion. Is provided. Further, in the adjustment task screw 27, the inner side end protruding from the cylinder space 7a to the inner side cannot be relatively rotated inside the final gear 31 constituting the speed reducer 11a housed in the casing 26. Is engaged. Thus, the adjustment task screw 27 can be rotationally driven by the electric motor 9a, and the adjustment task screw 27 is used as an input member of the thrust generating mechanism 8a. The adjuster sleeve 28 includes a screw cylinder main body 33 having an internal thread part 32 on an inner peripheral surface provided in an inner side half part, and a cylindrical support cylinder part 34 provided in an outer side half part. The adjusting task screw 27 is arranged around the outer half portion. Such an adjuster sleeve 28 can be displaced in the axial direction along with the rotation of the adjuster screw 27 by screwing the female screw part 32 into the male screw part 29.

  In the case of this example, an adjuster case 35 is provided so as to span between the inner end of the cylinder space 7a and the casing 26 while covering the intermediate portion of the adjuster screw 27. The adjuster case 35 is formed in a stepped cylindrical shape having a large diameter on the outer side and a small diameter on the inner side, and an intermediate portion of the adjuster screw 27 can be inserted into the inside thereof. Such an adjuster case 35 is fitted and fixed inside a through-hole 37 formed in the back end wall 36 of the caliper 5a so as not to be displaced toward the inner side. The portion is inserted inside the opening 38 of the casing 26 without rattling. An axial force sensor unit 39 for measuring an axial load, a thrust bearing 40 (ball and the other race ring), between the adjuster case 35 and the thrust receiving portion 30 of the adjustment task screw 27. Is arranged.

The force-increasing mechanism 14 a includes a drive-side rotor 41, a driven-side stator 42, three tapered rollers 43 and 43, and a guide ring 44.
Of these, the drive-side rotor 41 serving as an input member of the force-increasing mechanism 14a is configured in a substantially annular shape, and cannot be relatively rotated around the intermediate portion of the adjuster sleeve 28 and cannot be displaced toward the inner side. I support it. For this purpose, a pair of engaging protrusions 45, 45 having a radially inner side surface as a flat surface are provided on the diametrically opposite portion of the inner side end of the drive side rotor 41. The engaging protrusions 45 and 45 are engaged with a pair of flat surface portions provided on the diametrically opposite side of the outer peripheral surface of the screw cylinder main body 33. The inner side surface of the inner diameter side portion of the drive side rotor 41 is abutted against the outer side surface of the screw cylinder main body 33. Further, three driving side ramp tracks 46 are formed on the driving side surface (outer side surface) of the driving side rotor 41 facing the piston 12a. Each of the drive-side ramp tracks 46, 46 is a partial arc shape that is present on a single arc centered on the center of the piston 12a as viewed from the axial direction, and the cross-sectional shape (bus shape) is a linear shape. It is. The height in the axial direction gradually changes in the same direction with respect to the circumferential direction.

  In addition, a resistance is applied to the drive-side rotor 41 so that the drive-side rotor 41 and the adjuster sleeve 28 do not rotate in the rotation direction of the adjustment task screw 27 during braking operation. Therefore, in the case of this example, a compression coil spring 47 is provided between the drive-side rotor 41 and the piston 12a. Specifically, an annular connecting ring 48 is engaged around the drive-side rotor 41 so as not to be relatively rotatable, and the compression coil spring is inserted into a mounting hole 49a provided in a part of the connecting ring 48 in the circumferential direction. One end of 47 is locked. The other end of the compression coil spring 47 is provided on one guide protrusion 51 of the pair of guide protrusions 51, 51 provided on the opposite side in the diameter direction of the substantially annular guide member 50. It is locked in the mounting hole 49b. The guide member 50 causes the guide protrusions 51 and 51 to enter the insides of the slits 24 and 24 so that the guide member 50 is relatively non-rotatable and axially displaced inside the proximal end portion of the piston 12a. Arranged to be possible. In the case of this example, by arranging the compression coil spring 47 in this way, the drive side rotor 41 is driven in the direction opposite to the rotation direction of the adjuster screw 27 during braking operation. In order to reduce the axial distance between the side rotor 41 and the driven side stator 42, resistance (elasticity) in a direction in which the taper rollers 43 and 43 roll is applied. The magnitude of this resistance is the screwed portion between the male screw portion 29 and the female screw portion 32 when the both sides of the rotor 1 and the pads 2 and 3 are separated from each other in the non-braking state. The resistance is set to be smaller than the resistance of the threaded portion between the male screw portion 29 and the female screw portion 32 when both side surfaces of the rotor 1 and the pads 2 and 3 are in contact with each other. ing. In the case of this example, in order to restrict the displacement of the guide member 50 toward the inner side, a locking groove 52 is formed over the entire circumference on the inner peripheral surface of the base end portion of the piston 12a. A retaining ring 53 is locked inside the groove 52.

  The driven-side stator 42 is provided such that it cannot be rotated relative to the piston 12a and can be displaced in the axial direction. For this reason, in the case of this example, the driven-side stator 42 is connected to the piston 12a via a substantially annular detent plate 54 that is engaged around the driven-side stator 42 so as not to be relatively rotatable. The relative rotation is impossible. Specifically, each of the outer peripheral surfaces of the outer half of the driven-side stator 42 is cut away from the diametrically opposite portion, thereby forming engagement male portions 55 and 55 in the corresponding portions. The engaging male portions 55 and 55 are engaged with engaging female portions 56 and 56 formed on the diametrically opposite portion of the inner peripheral surface of the rotation stop plate 54, respectively. In addition, a pair of guide protrusions 57 and 57 formed in a radially projecting state on the opposite side of the outer peripheral surface of the anti-rotation plate 54 in the radial direction are inserted into the slits 24 and 24. Yes. Thus, the driven-side stator 42 is provided so as not to rotate relative to the piston 12a and to be axially displaceable. Further, the driven side stator 42 is externally fitted and supported on the outer side end portion of the support cylinder portion 34 constituting the adjuster sleeve 28 so as to be relatively rotatable.

  Further, the outer side surface (tip surface) of the driven-side stator 42 that comes into contact with the receiving surface 22 provided on the bottom portion 21 of the piston 12a has a spherical shape so that the piston 12a can be slightly oscillated and displaced. Convex surface. On the contrary, on the driven side surface, which is the inner side surface of the driven side stator 42, the same number (three) of driven side lamp tracks 58, 58 as the driving side lamp tracks 46, 46 are provided. It forms in the state which opposes the track | orbits 46 and 46 in an axial direction. Each of the driven-side lamp tracks 58, 58 has a partial arc shape when viewed from the axial direction, and a cross-sectional shape (bus shape) is a linear shape. The height in the axial direction gradually changes in the same direction with respect to the circumferential direction between the driven ramp tracks 58 and 58 and in the opposite direction to the driving ramp tracks 46 and 46.

  Each of the taper rollers 43 and 43 has a truncated cone shape whose outer diameter changes in the axial direction, and is made of a hard metal material such as high carbon chromium bearing steel. Further, the small-diameter side end surface and the large-diameter side end surface of each of the taper rollers 43, 43 are convex curved surfaces (partial spherical convex surfaces) in which the respective central portions (points on the center line of the taper roller 43) protrude most in the axial direction. In the case of this example, such three taper rollers 43 and 43 are arranged at equal intervals (120 degree intervals) in the circumferential direction, and the drive side lamp tracks 46 and 46 and the driven side lamps are arranged. Each of the central axes is sandwiched between the tracks 58 and 58 in a diametrical direction (the small diameter side end is on the inner diameter side and the large diameter side end is on the outer diameter side). In this state, the taper rollers 43 and 43 are rotatably held in pockets 60 and 60 formed at three positions in the circumferential direction of a substantially annular retainer 59. Each of these pockets 60, 60 has a shape in which a radially outer end portion is opened. For this reason, the radially outer end portions of the taper rollers 43 and 43 protrude radially outward from the pockets 60 and 60, respectively.

  A cylindrical guide ring 44 made of a hard metal such as high carbon chrome bearing steel is disposed around the taper rollers 43 and 43 and inside the side wall 23 of the piston 12a. Yes. And the center part of the large diameter side end surface (radial direction outer end surface) of each said taper roller 43 and 43 is made to contact | abut to the inner peripheral surface of this guide ring 44, respectively.

The electric disc brake device of the present example configured as described above operates as follows to press 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 inner and outer pads 2 and 3 and both side surfaces of the rotor 1. From this state, in order to perform braking, the electric motor 9a is energized, and the adjust screw 27 constituting the feed screw mechanism 13a is rotationally driven via the speed reducer 11a. In this state, the resistance generated at the threaded portion between the male screw portion 29 and the female screw portion 32 is smaller than the resistance (elasticity) applied to the drive-side rotor 41 by the compression coil spring 47. For this reason, the adjuster sleeve 28 and the drive-side rotor 41 are not rotated but displaced (translated) toward the outer side toward the rotor 1. Then, the piston 12a is pushed out from the cylinder space 7a through the taper rollers 43, 43 and the driven-side stator 42. As a result, the inner pad 2 is pressed against the inner side surface of the rotor 1 by the piston 12a, and the caliper 5a is displaced toward the inner side, and the caliper claw 6 causes the outer pad 3 to be moved to the outer side of the rotor 1. Press against the side. In this way, the force-increasing mechanism 14a does not function particularly while the gap between the pads 2 and 3 and the both side surfaces of the rotor 1 is eliminated.

  When the gap between the pads 2 and 3 and both side surfaces of the rotor 1 is eliminated, the resistance generated at the threaded portion between the male screw portion 29 and the female screw portion 32 due to the generation of axial force. And the function of the feed screw mechanism 13a stops (the adjuster sleeve 28 and the drive side rotor 41 do not rotate relative to the adjuster screw 27), the adjuster sleeve 28 and the drive side rotor 41 are compressed. It is rotated against the elasticity (resistance) of the coil spring 47. Accordingly, the taper rollers 43 and 43 roll toward the higher side in the axial direction of the drive-side ramp tracks 46 and 46 and the driven-side ramp tracks 58 and 58, respectively. At this time, the guide ring 44 is rotated along with the revolving motion of the taper rollers 43 and 43. Based on the engagement (rolling contact) between the drive-side ramp tracks 46 and 46 and the driven-side ramp tracks 58 and 58 and the taper rollers 43 and 43, the drive-side rotor 41 and the driven-side ramp tracks The distance from the drive side stator 42 is increased with a large force. As a result, the outer side surface of the piston 12 a is strongly pressed against the inner side surface of the inner pad 2. As a result, the inner and outer pads 2 and 3 are strongly pressed against both side surfaces in the axial direction of the rotor 1 to generate a braking force.

  When braking is released, the output shaft of the electric motor 9a is rotated in the direction opposite to that during braking based on the energization of the electric motor 9a. Then, each part is displaced in the direction opposite to that at the time of braking described above, and the piston 12a is retracted into the cylinder space 7a. As a result, gaps exist between the two pads 2 and 3 and both side surfaces of the rotor 1.

According to the electric disk brake device of the present example having the above-described configuration and operating as described above, a large braking force can be obtained while ensuring sufficient durability.
That is, in the case of this example, the force-increasing mechanism 14a constituting the thrust generating mechanism 8a is replaced with a ball-and-ramp-type force-increasing mechanism that uses a conventional ball, and force-increasing mechanisms that use the taper rollers 43 and 43, respectively. Is adopted. For this reason, the contact state of the rolling contact portion between the rolling surface of each taper roller 43, 43 and each of the driving-side and driven-side ramp raceways 46, 58 can be changed from point contact to line contact. The surface pressure of the part can be kept low. Therefore, in order to obtain a large braking force, for example, when the thrust generated by the force-increasing mechanism 14a is increased by, for example, loosening the inclination angle of each of the driving-side and driven-side ramp tracks 46, 58, each of these It is possible to effectively prevent a large stress from being generated in the ramp tracks 46 and 58. As a result, according to the structure of this example, it is possible to realize an electric disc brake device that can obtain a large braking force while ensuring sufficient durability.

  Each of the taper rollers 43 and 43 has a circumferential length that changes in accordance with an axial position (a radial position of the force-increasing mechanism 14a). When rolling the driven-side ramp tracks 46, 58 (moving in the circumferential direction), the rolling surfaces of the tapered rollers 43, 43 and the driving-side and driven-side ramp tracks 46, 58 It is possible to prevent slippage between the two. In addition, each of the taper rollers 43 and 43 is clamped between the driving-side ramp tracks 46 and 46 and the driven-side ramp tracks 58 and 58, so that a component force directed radially outward is obtained. However, this component force can be supported by the guide ring 44 disposed around the taper rollers 43 and 43. Therefore, it is possible to stabilize the radial positions of the taper rollers 43 and 43 when the drive-side rotor 41 rotates. Therefore, each of these taper rollers 43 and 43 can be smoothly rolled, and the efficiency (axial force conversion efficiency) for converting the rotational force of the drive-side rotor 41 into thrust that is axial force can be increased.

  Further, the drive side rotor 41 and the adjuster sleeve 28 can be configured integrally, but in the case of this example, the drive side rotor 41 and the adjuster sleeve 28 are configured separately. For this reason, it is possible to easily perform the manufacturing work of the drive-side rotor 41 and the adjuster sleeve 28 as compared with the case where they are integrally formed.

  In the case of this example, when the force-increasing mechanism 14a is operated, the driven-side stator 42 that rotates relative to the driving-side rotor 41 is replaced with the adjuster sleeve that supports the driving-side rotor 41. 28 is supported so as to be relatively rotatable so that it can be relatively rotated. For this reason, the coaxiality of the drive side rotor 41 and the driven side stator 42 can be increased. Therefore, the operation at the time of braking can be performed stably.

In addition, the driven side stator 42 is engaged with the piston 12a through the non-rotating plate 54, which is separate from the driven side stator 42, so that the driven side stator 42 cannot rotate relative to the driven side stator 42. Of the stator 42, the degree of freedom regarding the shape of the portion other than the portion with which the anti-rotation plate 54 is engaged can be increased. For this reason, in the driving side stator 41, the shape of the tip surface that contacts the inner end surface of the piston 12a is a spherical convex surface, or the shape of the outer peripheral surface arranged on the inner diameter side of the guide ring 44 is a cylindrical surface. The design to do becomes easy.
Other configurations and operational effects are the same as those of the conventional structure described above.

  The present invention can be applied not only to a floating caliper type disc brake but also to an opposed piston type disc brake.

DESCRIPTION OF SYMBOLS 1 Rotor 2 Inner pad 3 Outer pad 4 Support 5, 5a Caliper 6 Caliper claw 7, 7a Cylinder space 8, 8a Thrust generating mechanism 9, 9a Electric motor 10 Output shaft 11, 11a Reducer 12, 12a Piston 13, 13a Feed screw mechanism 14, 14a Booster 15 Drive-side rotor 16 Driven-side ramp groove 17 Driven-side stator 18 Driven-side ramp groove 19 Ball 20 Guide pin 21 Bottom portion 22 Receiving surface 23 Side wall portion 24 Slit 25 Seal ring 26 Casing 27 Adjustable screw 28 Adjuster sleeve 29 Male thread part 30 Thrust receiving part 31 Final gear 32 Female thread part 33 Screw cylinder body 34 Support cylinder part 35 Adjuster case 36 Back end wall 37 Through hole 38 Opening part 39 Axial force sensor unit 40 Thrust bearing 41 Drive side Motor 42 driven side stator 43 taper roller 44 guide ring 45 engaging projection 46 driving side ramp track 47 compression coil spring 48 connecting ring 49a, 49b mounting hole 50 guide member 51 guide projection 52 locking groove 53 retaining ring 54 around Stop plate 55 Engagement male part 56 Engagement female part 57 Guide protrusion 58 Driven side ramp track 59 Cage 60 Pocket

Claims (3)

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. And a pair of pads on the outer side and the inner side, and a cylinder space provided in a portion of the pad opposite to the axial side surface of at least one of the pads, the axial displacement of the rotor is provided. In an electric disc brake device comprising: a piston that is moved, and an electric actuator that presses the two pads against both axial sides of the rotor by displacing the piston in a direction of pushing it out of the cylinder space.
An electric motor that rotates the output shaft in both directions based on energization; and a feed screw mechanism that converts the rotational driving force of the electric motor into axial thrust and pushes the piston out of the cylinder space. A thrust generating mechanism having a boosting mechanism,
Of these, the feed screw mechanism has a male screw portion on the outer peripheral surface, and an adjust screw that is rotationally driven by the electric motor and a female screw portion provided on the inner peripheral surface are screwed into the male screw portion, thereby adjusting the adjuster screw. It is equipped with an adjuster sleeve that can be displaced in the axial direction as the screw rotates,
The force-increasing mechanism is supported so as not to rotate relative to the adjuster sleeve, and a driving side ramp orbit whose height in the axial direction gradually changes in the same direction with respect to the circumferential direction is provided on the driving side surface facing the piston. A plurality of driven-side ramp tracks whose height in the axial direction gradually changes in a direction opposite to the driving-side ramp track in the circumferential direction on the driven-side rotor having an axial direction opposite to the driving side surface; A driven-side stator that is axially displaceable with respect to the piston and incapable of relative rotation, and rolls between each of the driving-side ramp tracks and each of the driven-side ramp tracks. A plurality of taper rollers sandwiched between the taper rollers and the taper rollers are arranged around the taper rollers, and the radially outer end surface central portions of the taper rollers are in contact with the inner peripheral surfaces of the taper rollers, respectively. Electric disc brake apparatus, wherein the is obtained a Idoringu.   2. The electric disk brake device according to claim 1, wherein the driven-side stator is externally fitted and supported so as to be relatively rotatable at an end portion of the adjuster sleeve closer to the rotor in the axial direction.   The driven-side stator is engaged with the piston in a relatively non-rotatable manner via a substantially annular non-rotating plate that is engaged with the driven-side stator in a relatively non-rotatable manner. The electric disc brake device described in any one of 1-2.

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