JP3881966B2 - Disc brake device gap adjustment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the clearance adjusting device of a disk brake system having fewer components in a simple structure, which dispenses rotary drive source for a screw mechanism adjusting an amount of wear of a friction pad. <P>SOLUTION: The disk brake system comprises a piston 28 engaging the friction pads 12 and 13 with a brake disk 11, a seal member 32 rolling back the piston 28 with a predetermined amount, an output transmitting member 34 engaging with the piston 28 via the first screw mechanism S1, an input member 17 capable of pressuring the output transmitting member 34 by moving forward by means of an electric motor 22, an adjustment member 35 engaging with the output transmitting member 34 via the second screw mechanism S2 being opposed to the first screw mechanism S1, a clutch mechanism 39 restricting rotation of the adjustment member 35, and a coil spring 36 urging the adjustment member 35 to a moving-forward direction. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a gap adjusting device for keeping a pad clearance between a brake disc and a friction pad of a disc brake device constant regardless of wear of the friction pad.
[0002]
[Prior art]
  A gap adjusting device for such a disc brake device is known, for example, from the following patent document. In this disk brake device, a ball in ramp mechanism and an electric motor are arranged in series on the axis of a piston that presses a friction pad, and the rotor of the electric motor is directly connected to the rotating disk of the ball in ramp mechanism. This is a so-called electric brake device that operates the ball-in ramp mechanism by rotating the shaft to drive the piston.
[0003]
  The piston is screwed to the adjustment nut, and the adjustment nut rotates by the amount of wear of the friction pad to push the piston forward, so that the pad clearance is kept constant. Between the rotor of the electric motor and the adjustment nut, a limiter mechanism that allows the rotor and the adjustment nut to relatively rotate within a predetermined rotation angle range is engaged when the rotor rotates forward in the direction in which the piston moves forward. And a one-way clutch that disengages when the rotor reverses in the direction to retract the piston.
[0004]
  When the rotor of the electric motor is rotated forward to advance the piston while the friction pad is worn, the limiter mechanism is idled while the rotor advances the piston by the regular pad clearance via the ball in-ramp mechanism. The adjustment nut does not rotate, and while the rotor further rotates and advances the piston by the wear amount of the friction pad, the limiter mechanism engages and the adjustment nut rotates, and the piston moves forward with respect to the adjustment nut. Part of the wear amount of the friction pad is adjusted. When the rotor of the electric motor is reversed to release the braking force by moving the piston backward, the limiter mechanism engages in the process to reverse the adjustment nut, but the one-way clutch is disengaged. Since the rotation of the rotor is not transmitted to the adjusting nut, the reverse rotation of the adjusting nut is prevented and the adjustment of the wear amount once performed is prevented from returning to the original.
[0005]
  In this way, a part of the wear amount of the friction pad is adjusted in the course of one reciprocation of the piston, and the total amount of wear of the friction pad can be adjusted by repeating this.
[0006]
[Patent Document] JP 2000-346109 A
[0007]
[Problems to be solved by the invention]
  However, the conventional disc brake device gap adjusting device requires a limiter mechanism and a one-way clutch, so that the structure is complicated and the number of parts increases, and the adjusting nut is adjusted by the rotational force of the rotor of the electric motor. Since the amount of wear of the friction pad is adjusted by rotating it, it cannot be applied to a piston that directly moves forward or backward by hydraulic pressure like a hydraulic brake device, and there is a problem that its versatility is low.
[0008]
  The present invention has been made in view of the above circumstances, and does not require a rotational drive source for a screw mechanism for adjusting the wear amount of a friction pad, and has a small number of parts and a simple structure, and a gap adjusting device for a disc brake device. The purpose is to provide.
[0009]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, there is provided a piston arranged to be movable in the axial direction so as to engage the friction pad with the brake disc, and a frictional force when the piston moves forward. And a seal member that elastically deforms and retracts the piston after advancement by a predetermined amount by its elastic restoring force, and is arranged to be movable in the axial direction and rotatable about the axial line, and is engaged with the piston via the first screw mechanism An output transmission member that is movably disposed in the axial direction, an input member that can be advanced by a drive source to press the output transmission member, and that is movable in the axial direction and rotatable about the axial line, and the first screw Mechanism and reverse screwIn addition, the screw diameter is larger than that of the first screw mechanism and is arranged in the axial direction through a step with the first screw mechanism.An adjustment member that is engaged with the output transmission member via the second screw mechanism, a first clutch surface provided forward on the adjustment member, and a second clutch surface provided rearward on the input member, and the axis of the adjustment member A clutch mechanism that constrains rotation of the surroundings, and an adjustment member that urges the output transmission member in a forward direction, and the adjustment member rotates relative to the output transmission member when the first and second clutch surfaces are separated. With biasing meansThe adjustment member is formed in a cylindrical shape surrounding the first and second screw mechanisms, and biasing means is disposed on the inner periphery thereof, and the biasing means and the axial front end side of the adjustment member are arranged. The arranged clutch mechanism is positioned within the axial width of the first screw mechanism around the first screw mechanism.A gap adjusting device for a disc brake device is proposed.
[0010]
  According to the above configuration, when the input member is advanced by the drive source and the output transmission member is pressed with the friction pad worn, the piston connected to the output transmission member via the first screw mechanism defines the seal member. It moves forward while being elastically deformed, and presses the friction pad to engage the brake disc to generate a braking force. When the input member is retracted to the original position to release the braking force, the piston is retracted only by the specified amount due to the elastic restoring force of the seal member. Therefore, the input member to be further retracted is coupled to the piston via the clutch mechanism. The piston is pulled rearward through the adjusted member, the output transmission member connected thereto via the second screw mechanism, and the first screw mechanism provided thereon.
[0011]
  As a result, the second screw mechanism slips and the output transmission member rotates relative to the adjustment member and the piston, which are restrained so as not to rotate, so that the piston is pushed forward with respect to the output transmission member by the first screw mechanism. At the same time, since the output transmission member is drawn forward with respect to the adjustment member, a gap is generated between the input member and the output transmission member. Subsequently, in the process of the advancement of the input member again, the input member is idled by the gap, and the first and second clutch surfaces of the clutch mechanism are separated from each other. Therefore, the second screw mechanism slips due to the urging force of the urging means. Then, the adjustment member moves forward with respect to the output transmission member, and the clutch mechanism is engaged again. Through the above process, the piston advances by a part of the wear amount of the friction pad with respect to the output transmission member. By repeating this, the entire wear amount of the friction pad is finally adjusted.
[0012]
  As described above, when the piston moves backward, the first screw mechanism rotates to push the piston forward with respect to the output transmission member, and the amount of wear is adjusted. This is only a part of the amount, and by repeating this, the total amount of friction pad wear is finally adjusted, so excessive adjustment beyond the friction pad wear amount when a large load is applied to the input member Can be prevented.
[0013]
  In addition, since there is no need for a rotation drive source for the first and second screw mechanisms for adjusting the wear amount of the friction pad, and the input member only has to be moved forward and backward in the axial direction, any drive source for hydraulic and electric motors can be used. It becomes possible to apply also to the disc brake device using, and versatility is improved. In addition, since the limiter mechanism and one-way clutch that were required in the past are no longer required, the structure can be simplified and the number of parts can be reduced.The
[0014]
  The brake disk 11 of the embodiment corresponds to the braked member of the present invention, the first friction pad 12 and the second friction pad 13 of the embodiment correspond to the braking member of the present invention, and the electric motor 22 of the embodiment is Corresponding to the drive source of the present invention, the coil spring 36 of the embodiment corresponds to the biasing means of the present invention.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.
[0016]
  1 to 9 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of an electric disc brake device, FIG. 2 is an enlarged view of a part 2 in FIG. 1, and FIG. 3 is a line 3-3 in FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a diagram showing a state when the input member is advanced, FIG. 6 is a diagram showing a state when the input member is retracted, and FIG. FIG. 8 is a diagram showing a state when re-advance is started, FIG. 8 is a diagram showing a state where the input member is being re-advanced, and FIG. 9 is a diagram showing a state when the input member is re-retreated.
[0017]
  As shown in FIGS. 1 to 4, in the electric brake device, the first friction pad 12 and the second friction pad 13 are arranged opposite to each other of the brake disk 11 that rotates together with the wheels. The second friction pads 12 and 13 are composed of linings 12a and 13a that can come into contact with the brake disk 11, and back plates 12b and 13b fixed to the back surfaces of the linings 12a and 13a. , 13b are supported by the bracket 14 fixed to the vehicle body so as to be movable in the direction of the axis L of the piston 28. A brake caliper 15 straddling the first and second friction pads 12 and 13 is supported by the bracket 14 so as to be movable in the direction of the axis L.
[0018]
  In this specification, the left side of the piston 28 in the direction of the axis L is defined as the front, and the right side is defined as the rear. Accordingly, when the piston 28 moves forward to the left and presses the first friction pad 12, a braking force is generated, and when the piston 28 moves backward to the right, the braking force is released.
[0019]
  The brake caliper 15 includes a first sandwiching arm 15a facing the back plate 12b of the first friction pad 12, and a second sandwiching arm 15b facing the back plate 13b of the second friction pad 13. The second sandwiching arms 15 a and 15 b are integrally connected by a bridging portion 15 c that passes through the outer peripheral portion of the brake disk 11.
[0020]
  A substantially cylindrical input member 17 is slidably supported in the direction of the axis L in the guide hole 16 formed in the first sandwiching arm 15a. A large-diameter first rotor 18 and a small-diameter second rotor 19 are supported on the outer periphery of the input member 17 so as to be rotatable relative to each other, and each of the plurality of first and second rotors 18 and 19 formed on the opposing surfaces. Balls 20... Are arranged between the three (three in the embodiment) cam grooves 18 a. These cam grooves 18a... 19a... And balls 20 constitute a ball in ramp mechanism 40 of the present invention.
[0021]
  An electric motor 22 is housed inside a motor holder 21 provided on the right side surface of the first sandwiching arm 15a, and a small-diameter first drive gear 23 and a large-diameter second drive gear 24 are provided on the output shaft 22a. . The first drive gear 23 meshes with a first driven gear 18 b formed on the outer periphery of the large-diameter first rotor 18, and the second drive gear 24 meshes with a second driven gear 19 b formed on the outer periphery of the small-diameter second rotor 19. Therefore, when the output shaft 22a of the electric motor 22 rotates, the first rotor 18 and the second rotor 19 rotate relative to each other. Then, when the first rotor 18 and the second rotor 19 rotate relative to each other, the ball in-ramp mechanism 40 sandwiches the balls 20 between the cam grooves 18 a of the first rotor 18 and the cam grooves 19 a of the second rotor 19. The interval between the first rotor 18 and the second rotor 19 is increased.
[0022]
  At this time, by reducing the difference in the number of teeth between the first drive gear 23 and the second drive gear 24 (that is, the difference in the number of teeth between the first driven gear 18b and the second driven gear 19b), the first rotor 18 and the first The relative rotational speed between the two rotors 19 can be reduced, and the thrust force that increases the distance between the first and second rotors 18 and 19 can be increased. Therefore, a large thrust force can be generated by generating a sufficient thrust force with the small and small output electric motor 22 without using a complicated gear train with a large reduction ratio or a large output electric motor. Power can be secured, and the number of parts, assembly man-hours, cost, and the electric disk brake device can be reduced in size and weight.
[0023]
  Further, by reducing the difference in the number of teeth between the first drive gear 23 and the second drive gear 24 to ensure a large reduction ratio, reverse transmission of the driving force from the ball in-ramp mechanism 40 side to the electric motor 22 side is prevented. Therefore, it is not necessary to continue energizing the electric motor 22 while the braking force having a certain magnitude is generated. That is, since the electric power supply to the electric motor 22 needs to be performed only when the braking force is increased and decreased, it is possible to contribute to reduction of power consumption. Therefore, this electric brake device is suitable when used as a parking brake in addition to a service brake.
[0024]
  The right side surface of the second rotor 19 is supported by the first sandwiching arm 15a via the thrust washer 25, and movement in the right direction is restricted. The input member 17 urges the first flange 17a formed radially inward at the right end thereof to the right by a coil spring 26 disposed between the first sandwiching arm 15a and radially outward at the left end. The second flange 17 b formed in contact with the left side surface of the first rotor 18 through the thrust washer 27. Accordingly, when the electric motor 22 is driven to increase the distance between the first and second rotors 18 and 19, the input member 17 advances to the left with respect to the brake caliper 15 while compressing the coil spring 26.
[0025]
  The piston 28 movably disposed on the axis L has a pressing portion 28a facing the back surface of the back plate 12b of the first friction pad 12 so as to be in contact with the cylinder, and a cylinder extending rightward on the axis L from the pressing portion 28a. And a shaft portion 28b. An annular partition member 29 is fixed by a clip 30 between the pressing portion 28 a of the piston 28 and the second flange 17 b of the input member 17, and the outer peripheral surface of the partition member 29 is a first sandwiching arm via a seal member 31. The inner peripheral surface is in contact with the outer peripheral surface of the shaft portion 28b of the piston 28 via the seal member 32 so as to be slidable.
[0026]
  As apparent from FIG. 2, the seal member holding groove 29 a of the partition wall member 29 that holds the seal member 32 has a gap 29 b on the left side of the seal member 32, so that the seal member 32 is elastically deformed to the left side. The elastic deformation to the right side of the seal member 32 is restricted by allowing and not having a gap on the right side of the seal member 32.
[0027]
  A male screw formed on the outer periphery of the left half of the output transmission member 34 supported by the motor holder 21 via the seal member 33 and a female screw formed on the inner periphery of the shaft portion 28b of the piston 28 mesh with each other. The first screw mechanism S1. The first screw mechanism S1 is a single right-hand thread having a substantially triangular thread and a thread groove.
[0028]
  A cylindrical adjustment member 35 is fitted on the inner periphery of the input member 17 so as to be relatively rotatable. A female screw formed on the inner periphery of the input member 17 and a large-diameter portion 34b connected to the left side of the journal portion 34a of the output transmission member 34. The external thread formed on the outer periphery of theAligned axially with the first screw mechanism S1Configures the second screw mechanism S2The screw diameter is larger than that of the first screw mechanism S1.. The second screw mechanism S2 is a multiple thread (three threads in the embodiment) left-hand thread having a rectangular thread and a thread groove. That is, in the first screw mechanism S1 and the second screw mechanism S2, the turning directions of the screw threads and the screw grooves are reversed.
[0029]
  A coil spring 36 and a ball bearing 37 are arranged in series between a flange portion 35a projecting radially inward from the left end of the adjustment member 35 and the left end of the large diameter portion 34b of the output transmission member 34. The adjustment member 35 is biased leftward with respect to the output transmission member 34 by the resilient force of the coil spring 36, whereby the first clutch surface 35 b at the left end of the adjustment member 35 is fixed to the inner peripheral surface of the input member 17. The clutch member 38 comes into contact with the right second clutch surface 38a. The first clutch surface 35b and the second clutch surface 38a constitute the clutch mechanism 39 of the present invention.The clutch mechanism 39 and the coil spring 36 are located around the first screw mechanism S1 and within the axial width thereof.
[0030]
  In this embodiment, the piston 28 and the input member 17 are made of iron, the output transmission member 34 is made of aluminum, and the adjustment member 35 is made of synthetic resin. By making the output transmission member 34 and the adjustment member 35 made of aluminum and synthetic resin, the rectangular screw threads and screw grooves of the second screw mechanism S2 can be easily molded. If the output transmission member 34 and the adjustment member 35 are made of iron, it cannot be molded due to the melting temperature of the iron, and it is very costly to produce rectangular threads and screw grooves by cutting. Becomes bulky.
[0031]
  Next, the operation of the electric brake device having the above configuration will be described.
[0032]
  First, the normal braking action when the first and second friction pads 12 and 13 are not worn will be described.
[0033]
  In FIG. 2, when the electric motor 22 is driven to rotate forward to move the input member 17 forward, the large diameter portion 34b is pressed against the first flange 17a of the input member 17, and the output transmission member 34 advances forward to the left. The piston 28 having the shaft portion 28b engaged with the transmission member 34 via the first screw mechanism S1 moves forward to the left side, thereby pressing the first friction pad 12 against one side of the brake disk 11. Then, the reaction causes the brake caliper 15 to retreat to the right in the direction opposite to the forward direction of the piston 28, and the second sandwiching arm 15 b presses the second friction pad 13 against the other side of the brake disk 11. As a result, the first and second friction pads 12 and 13 are brought into contact with both surfaces of the brake disc 11 with an equal surface pressure, and a braking force for braking the wheel is generated. At this time, the adjustment member 35 moves integrally with the input member 17 and the output transmission member 34.
[0034]
  Thus, when the piston 28 advances to the left side, the seal member 32 that contacts the outer periphery of the shaft portion 28b of the piston 28 is elastically deformed so as to be dragged to the left inside the seal member holding groove 29a. The stroke amount of the piston 28, that is, an appropriate pad clearance between the first and second friction pads 12 and 13 and the brake disk 11 is set so that 32 does not slip with respect to the shaft portion 28b of the piston 28. .
[0035]
  When the electric motor 22 is reversely driven from this state to return the input member 17 to the initial position, the piston 28 is moved back to the right side by the rollback force that restores the elastically deformed seal member 32 to the original shape, thereby transmitting the output. The member 34 and the adjusting member 35 are also retracted to the right so as to follow the input member 17. That is, when an appropriate pad clearance is set between the first and second friction pads 12 and 13 and the brake disk 11, the stroke amount by which the piston 28 advances to the left side and the rollback by which the piston 28 moves backward to the right side. It is consistent with the quantity.
[0036]
  A stopper (not shown) for restricting the first and second rotors 18 and 19 to the initial position is provided, and the electric motor 22 is driven in reverse to restrict the first and second rotors 18 and 19 to the initial position. If the energization is stopped when the current flowing through the electric motor 22 suddenly increases, the input member 17 can be accurately stopped at the initial position.
[0037]
  Next, the braking action when the first and second friction pads 12, 13 are worn will be described.
[0038]
  When the electric motor 22 is driven and the input member 17 is advanced to the left from the state shown in FIG. 2 to the state shown in FIG. 5, if the first and second friction pads 12 and 13 are worn, A distance X + X ′ (X ′ is the first and second frictions) larger than the pad clearance X at the normal time (when the first and second friction pads 12 and 13 are not worn), that is, the rollback amount X of the seal member 32. Therefore, a slip having a distance equal to the wear amount X ′ is generated between the seal member 32 and the piston 28.
[0039]
  When the electric motor 22 is reversely rotated to release the braking, as shown in FIG. 6, the input member 17 and the adjusting member 35 engaged with the input member 17 via the clutch mechanism 39 are separated by the elastic force of the coil spring 26 to the distance X + X. The piston 28 and the output transmission member 34 can be retracted to the right only by the rollback amount X of the seal member 32, while being retracted to the right by '. This is because even if the piston 28 tries to retreat to the right side beyond the rollback amount X, a very large frictional force acting between the piston 28 and the seal member 32 restricts the retraction of the piston 28.
[0040]
  In this way, when the adjustment member 35 attempts to move backward to the right by the wear amount X ′ of the first and second friction pads 12 and 13 with respect to the output transmission member 34, the adjustment member 35 rotates due to the engagement of the clutch mechanism 39. The output transmission member 34 rotates in the direction of the arrow R1 via the second screw mechanism S2 with respect to the constrained adjustment member 35. Since the piston 28 meshing with the output transmission member 34 via the first screw mechanism S1 is restrained so as not to rotate with respect to the first friction pad 12, the piston 28 is caused by relative rotation between the output transmission member 34 and the piston 28. The output transmission member 34 is pushed to the left by a distance Lup. On the other hand, the output transmission member 34 that meshes with the adjustment member 35 via the second screw mechanism S2 that is a left screw is pulled to the left by a distance Ldn with respect to the adjustment member 35 by relative rotation in the arrow R1 direction.
[0041]
  As a result, as shown in FIG. 6, a gap corresponding to the distance Ldn remains between the first flange 17a of the input member 17 and the large diameter portion 34b of the output transmission member 34, and the first and second The wear amount X ′ of the friction pads 12 and 13 is adjusted not only in the total amount but only in a part leaving the distance Ldn.
[0042]
  Hereinafter, the above operation will be described quantitatively.
[0043]
  The distance that the piston 28 advances to the left side with respect to the output transmission member 34 by one operation of the piston 28 is Lup, and the output transmission member 34 advances to the left side with respect to the adjustment member 33 by one operation of the piston 28. When the distance to be performed is Ldn, the adjustment amount X ′ that is originally required (that is, the wear amount of the first and second friction pads 12 and 13) is:
                          X ′ = Lup + Ldn
It is represented by
[0044]
  Here, if the rotation speed of the output transmission member 34 is n, the pitch of the first screw mechanism S1 is P1, the pitch of the second screw mechanism S2 is P2, and the number of threads is N,
                          Lup = nP1
                          Ldn = nNP2
It is represented by
[0045]
  Accordingly, the ratio R of the amount adjusted by one operation of the piston 28 to the adjustment amount X ′ originally required is
    R = Lup / (Lup + Ldn) = (nP1) / (nP1 + nNP2)
                                  = P1 / (P1 + NP2)
It is represented by
[0046]
  As is clear from the above equation, the ratio R is such that the larger the pitch P1 of the first screw mechanism S1 that is a single thread, the smaller the pitch P2 and the number N of the second screw mechanism S2 that is a multi-thread. It gets bigger. On the contrary, the ratio R becomes smaller as the pitch P1 of the first screw mechanism S1 that is a single thread is smaller, and as the pitch P2 and the number N of the second screw mechanism S2 that is a multi-thread are larger.
[0047]
  Now, when the electric motor 22 is driven again from the state of FIG. 6 and the input member 17 is moved to the left side, as shown in FIG. 7, the gap Ldn between the input member 17 and the output transmission member 34 disappears. When pushed by the input member 17, the output transmission member 34, the adjustment member 35, and the piston 28 move to the left. At this time, the input member 17 is idly moved to the left by the gap Ldn, so that the left-side first clutch surface 35b of the adjustment member 35 and the right-side second clutch surface 38a of the clutch member 38 are separated by a distance Ldn. . Then, the adjustment member 35 urged to the left side by the elastic force of the coil spring 36 slips in the direction of the arrow R2 with respect to the output transmission member 34 by the second spring mechanism S2, and as shown in FIG. Engage again. At this time, since the second spring mechanism S2 has a rectangular thread and a thread groove with less frictional force, the second spring mechanism S2 slips smoothly and relatively rotates the adjustment member 35 and the output transmission member 34.
[0048]
  Thereafter, when the piston 28 is further advanced by the electric motor 22, the first and second friction pads 12 and 13 come into contact with the brake disk 11 to generate a braking force. In order to release the braking force from this state, as shown in FIG. 9, when the electric motor 22 is driven in reverse, the same action as the first retraction of the piston 28 described in FIG. 6 is repeated, and the remaining unadjusted amount. A part of the certain distance Ldn is further adjusted. In this way, each time the piston 28 is repeatedly advanced and retracted, the initial wear amount X ′ of the first and second friction pads 12 and 13 is gradually adjusted, and finally the first and second friction pads 12 and 13 are finally adjusted. The pad clearance X between the brake disks 11 converges to a set value, that is, the normal stroke amount of the piston 28.
[0049]
  If the electric motor 22 fails during the operation of the brake, a wrench is inserted into the hexagonal hole 34c formed at the right end of the output transmission member 34 and rotated to retreat the piston 28 so that the brake is applied. Can be deactivated.
[0050]
  As described above, only a part of the wear amount X ′ of the first and second friction pads 12, 13 is adjusted by one operation of the piston 28, and the first, Since the total amount of wear X ′ of the second friction pads 12 and 13 is adjusted, even when a very large load is applied so that the distance between the first and second sandwiching arms 15a and 15b of the brake caliper 15 is increased. It is possible to prevent excessive adjustment exceeding the wear amount of the first and second friction pads 12 and 13. As a result, it is possible to eliminate the over-adjustment prevention mechanism that has been necessary in the past, and the cost can be reduced by simplifying the structure. Further, the first and second screw mechanisms S1 and S2 for adjusting the wear of the first and second friction pads 12 and 13 do not require a rotational drive source, and the input member 17 is simply moved forward and backward in the direction of the axis L. Since the adjustment is performed, it can be applied to a disc brake device using any drive source of a hydraulic pressure and an electric motor, and versatility is improved.
[0051]
  Although the embodiments of the present invention have been described above, various design changes can be made without departing from the scope of the present invention.
[0052]
  For example, in the embodiment, the first screw mechanism S1 is a right-hand screw and the second screw mechanism S2 is a left-hand screw. However, the first screw mechanism S1 is a left-hand screw by reversing it, and the second screw mechanism S2 is a right-hand screw. It is also good.
[0053]
  Further, in the embodiment, the electric drive exemplified by the disk brake device using the electric motor 22 as a drive source, but the present invention can also be applied to a disk brake device using a hydraulic pressure or a cable as a drive source.
[0054]
【The invention's effect】
  As aboveBookAccording to the invention, after the piston moves forward and presses the friction pad against the brake disc to generate the braking force, when the piston moves backward to release the braking force, the first screw mechanism rotates to transmit the output. The piston is pushed forward with respect to the member, and the amount of wear is adjusted. However, the amount of adjustment is only a part of the amount of wear of the friction pad. Since the total amount is adjusted, it is possible to prevent excessive adjustment beyond the wear amount of the friction pad when a large load is applied to the input member.
[0055]
  In addition, since there is no need for a rotation drive source for the first and second screw mechanisms for adjusting the wear amount of the friction pad, and the input member only has to be moved forward and backward in the axial direction, any drive source for hydraulic and electric motors can be used. It becomes possible to apply also to the disc brake device using, and versatility is improved. In addition, since the limiter mechanism and one-way clutch that were required in the past are no longer required, the structure can be simplified and the number of parts can be reduced.The
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electric disc brake device
2 is an enlarged view of part 2 of FIG.
3 is a cross-sectional view taken along line 3-3 in FIG.
4 is a cross-sectional view taken along line 4-4 of FIG.
FIG. 5 is a diagram showing a state when the input member moves forward
FIG. 6 is a diagram showing a state in which the input member is retracted
FIG. 7 is a diagram showing a state when the input member starts re-advancing
FIG. 8 is a diagram showing a state in which the input member is re-advancing
FIG. 9 is a diagram showing a state of the input member when it is retracted again
[Explanation of symbols]
11 Brake disc (braking member)
12 First friction pad (braking member)
13 Second friction pad (braking member)
17 Input members
22 Electric motor (drive source)
28 piston
32 Seal member
34 Output transmission member
35 Adjustment members
35b First clutch surface
36 Coil spring (biasing means)
38a Second clutch surface
39 Clutch mechanism
L axis
S1 First screw mechanism
S2 Second screw mechanism

Claims (1)

A piston (28) arranged movably in the direction of the axis (L) to engage the friction pads (12, 13) with the brake disc (11);
A seal member (32) that is elastically deformed by a frictional force when the piston (28) moves forward, and retracts the piston (28) after the advancement by a specified amount by the elastic restoring force;
An output transmission member (34) arranged to be movable in the direction of the axis (L) and rotatable about the axis (L) and engaged with the piston (28) via the first screw mechanism (S1);
An input member (17) that is arranged so as to be movable in the direction of the axis (L) and can be advanced by the drive source (22) to press the output transmission member (34);
The first screw mechanism (S1) is reversely threaded with the first screw mechanism (S1) and has a screw diameter larger than that of the first screw mechanism (S1). An adjustment member (35) engaged with the output transmission member (34) via the screw mechanism (S1) and the second screw mechanism (S2) arranged in the axial direction via the step ;
The adjustment member (35) includes a first clutch surface (35b) provided forward and a second clutch surface (38a) provided rearward on the input member (17). The axis (L) of the adjustment member (35) A clutch mechanism (39) for restraining the rotation around,
The adjustment member (35) is urged in the forward direction with respect to the output transmission member (34), and the adjustment member with respect to the output transmission member (34) when the first and second clutch surfaces (35b, 38a) are separated. Urging means (36) for relatively rotating (35) ,
The adjustment member (35) is formed in a cylindrical shape surrounding the first and second screw mechanisms (S1, S2), and an urging means (36) is disposed on the inner periphery thereof.
The biasing means (36) and the clutch mechanism (39) disposed on the axially front end side of the adjusting member (35) are arranged around the first screw mechanism (S1) and the shaft of the first screw mechanism (S1). A gap adjusting device for a disc brake device, wherein the gap adjusting device is located within a direction width .

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