JP2004324805A - Clearance adjusting device of disk brake system - 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&NCIPI

Description

で表される。
【００５０】
上式から明らかなように、前記比率Ｒは、１条ねじである第１ねじ機構Ｓ１のピッチＰ１が大きいほど、また多条ねじである第２ねじ機構Ｓ２のピッチＰ２および条数Ｎが小さいほど大きくなる。逆に、前記比率Ｒは、１条ねじである第１ねじ機構Ｓ１のピッチＰ１が小さいほど、また多条ねじである第２ねじ機構Ｓ２のピッチＰ２および条数Ｎが大きいほど小さくなる。
【００５１】
さて、図６の状態から電動モータ２２を再度駆動して入力部材１７を左側に移動させると、図７に示すように、入力部材１７と出力伝達部材３４との間の隙間Ｌｄｎが消滅した後、入力部材１７に押されて、出力伝達部材３４、アジャスト部材３５およびピストン２８が左側に移動する。このとき、入力部材１７が前記隙間Ｌｄｎ分だけ左側に空動することで、アジャスト部材３５の左向きの第１クラッチ面３５ｂとクラッチ部材３８の右向きの第２クラッチ面３８ａとが距離Ｌｄｎだけ離間する。すると、コイルスプリング３６の弾発力で左側に付勢されたアジャスト部材３５が第２ばね機構Ｓ２で出力伝達部材３４に対して矢印Ｒ２方向にスリップし、図８に示すように、クラッチ機構３９が再び係合する。このとき、第２ばね機構Ｓ２は摩擦力が少ない矩形状のねじ山およびねじ溝を有しているため、スムーズにスリップしてアジャスト部材３５および出力伝達部材３４を相対回転させる。
【００５２】
その後、電動モータ２２でピストン２８を更に前進させると、第１、第２摩擦パッド１２，１３がブレーキディスク１１に当接して制動力が発生する。この状態から制動力を解除すべく、図９に示すように、電動モータ２２を逆転駆動すると、図６で説明したピストン２８の最初の後退時と同じ作用が繰り返され、残存する未調整量である距離Ｌｄｎの一部が更に調整される。このようにしてピストン２８の前進および後退を繰り返す度に、当初の第１、第２摩擦パッド１２，１３の摩耗量Ｘ′が次第に調整され、最終的に第１、第２摩擦パッド１２，１３およびブレーキディスク１１間のパッドクリアランスＸが設定値、つまりピストン２８の通常のストローク量に収束する。
【００５３】
尚、ブレーキの作動中に電動モータ２２が失陥したような場合には、出力伝達部材３４の右端に形成した六角孔３４ｃにレンチを挿入して回転させることで、ピストン２８を後退させてブレーキを作動解除することができる。
【００５４】
以上のように、ピストン２８の１回の作動で第１、第２摩擦パッド１２，１３の摩耗量Ｘ′の一部だけを調整し、ピストン２８の作動を繰り返すことで最終的に第１、第２摩擦パッド１２，１３の摩耗量Ｘ′の全量を調整するので、ブレーキキャリパ１５の第１、第２挟み腕１５ａ，１５ｂの間隔が広がるような非常に大きな荷重が作用した場合でも、第１、第２摩擦パッド１２，１３の摩耗量を超える過剰な調整が行われるのを防止することができる。その結果、従来必要であったオーバーアジャスト防止機構を廃止することが可能になり、構造の簡素化によるコストダウンを図ることができる。また第１、第２摩擦パッド１２，１３の摩耗を調整する第１、第２ねじ機構Ｓ１，Ｓ２の回転用駆動源が不要であり、入力部材１７を軸線Ｌ方向に前進および後退させるだけで調整が行われるため、油圧および電動モータの何れの駆動源を用いたディスクブレーキ装置にも適用することが可能になって汎用性が向上する。
【００５５】
以上、本発明の実施例を説明したが、本発明はその要旨を逸脱しない範囲で種々の設計変更を行うことが可能である。
【００５６】
例えば、実施例では第１ねじ機構Ｓ１を右ねじとし、第２ねじ機構Ｓ２を左ねじとしているが、それを逆にして第１ねじ機構Ｓ１を左ねじとし、第２ねじ機構Ｓ２を右ねじとしても良い。
【００５７】
また実施例では電動モータ２２を駆動源とするディスクブレーキ装置を例示した電動が、本発明は油圧やケーブルを駆動源とするディスクブレーキ装置に対しても適用することができる。
【００５８】
【発明の効果】
以上のように請求項１に記載された発明によれば、ピストンが前進して摩擦パッドをブレーキディスクに押し付けて制動力を発生させた後に、制動力を解除すべくピストンが後退する際に、第１ねじ機構が回転することで出力伝達部材に対してピストンが前方に押し出されて摩耗量の調整が行われるが、その調整量は摩擦パッドの摩耗量の一部だけであり、これを繰り返すことで最終的に摩擦パッドの摩耗量の全量を調整するので、入力部材に大きな荷重を加えたときに摩擦パッドの摩耗量を越えた過剰な調整が行われるのを防止することができる。
【００５９】
また摩擦パッドの摩耗量を調整する第１、第２ねじ機構の回転用駆動源が不要であり、入力部材を軸線方向に前進および後退させれば良いため、油圧および電動モータの何れの駆動源を用いたディスクブレーキ装置にも適用することが可能になって汎用性が向上する。しかも従来必要であったリミッタ機構や一方向クラッチが不要になるため、構造の簡素化および部品点数の削減が可能になる。
【００６０】
また請求項２に記載された発明によれば、第２ねじ機構が矩形状のねじ山およびねじ溝を有するので、第２ねじ機構の摺動摩擦抵抗を減少させてスムーズな作動を可能にすることができる。
【００６１】
また請求項３に記載された発明によれば、第２ねじ機構が合成樹脂製あるいはアルミニウム製であるので、矩形状のねじ山およびねじ溝を金型成形で容易に製造することができる。
【図面の簡単な説明】
【図１】電動ディスクブレーキ装置の横断面図
【図２】図１の２部拡大図
【図３】図２の３−３線断面図
【図４】図３の４−４線断面図
【図５】入力部材の前進時の状態を示す図
【図６】入力部材の後退時の状態を示す図
【図７】入力部材の再前進開始時の状態を示す図
【図８】入力部材の再前進中の状態を示す図
【図９】入力部材の再後退時の状態を示す図
【符号の説明】
１１ ブレーキディスク（被制動部材）
１２ 第１摩擦パッド（制動部材）
１３ 第２摩擦パッド（制動部材）
１７ 入力部材
２２ 電動モータ（駆動源）
２８ ピストン
３２ シール部材
３４ 出力伝達部材
３５ アジャスト部材
３５ｂ 第１クラッチ面
３６ コイルスプリング（付勢手段）
３８ａ 第２クラッチ面
３９ クラッチ機構
Ｌ 軸線
Ｓ１ 第１ねじ機構
Ｓ２ 第２ねじ機構[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a gap adjusting device for maintaining a constant pad clearance between a brake disk and a friction pad of a disk brake device regardless of wear of the friction pad.
[0002]
[Prior art]
Such a gap adjusting device for a disc brake device is known, for example, from the following patent document. In this disc 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 disc of the ball-in ramp mechanism. This is a so-called electric brake device in which a ball-in ramp mechanism is operated by rotating the piston to drive a 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, thereby maintaining a constant pad clearance. A limiter mechanism that allows the rotor and the adjustment nut to rotate relative to each other within a predetermined rotation angle range is engaged between the rotor and the adjustment nut of the electric motor when the rotor rotates forward in a direction to advance the piston. 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 with the friction pad worn, the limiter mechanism idles 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 amount of wear of the friction pad, the limiter mechanism is engaged and the adjustment nut rotates, and the piston is moved forward with respect to the adjustment nut. , A part of the wear amount of the friction pad is adjusted. Then, when the rotor of the electric motor is reversed in order to release the braking force by retracting the piston, the limiter mechanism is engaged in the process to try to reverse the adjustment nut, but the one-way clutch is disengaged. Since the rotation of the rotor is not transmitted to the adjustment nut, the rotation of the adjustment nut is prevented, and the adjustment of the wear amount once performed is prevented from returning to the original state.
[0005]
In this way, a part of the wear amount of the friction pad is adjusted in the process of one reciprocation of the piston, and the total amount of the wear amount of the friction pad can be adjusted by repeating the adjustment.
[0006]
[Patent Document]
JP 2000-346109 A
[Problems to be solved by the invention]
However, the above-described clearance adjusting device of the conventional disc brake device requires a limiter mechanism and a one-way clutch, which not only complicates the structure and increases the number of parts but also adjusts the adjusting nut by the rotational force of the rotor of the electric motor. Since the friction pad is rotated to adjust the wear amount, the friction pad cannot be applied to a hydraulic brake device in which the piston is directly advanced or retracted by hydraulic pressure, and there is a problem that its versatility is low.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and does not require a driving source for rotation of a screw mechanism for adjusting the wear amount of a friction pad, and has a small number of parts and a simple structure of a disc brake device with a simple structure. The purpose is to provide.
[0009]
[Means for Solving the Problems]
To achieve the above object, according to the first aspect of the present invention, a piston arranged to be movable in an axial direction so as to engage a friction pad with a brake disc, and a frictional force when the piston advances. A sealing member that is elastically deformed by the elastic restoring force and retreats the piston after advance by a predetermined amount by its elastic restoring force, and is disposed so as to be movable in the axial direction and rotatable around the axis and engaged with the piston via the first screw mechanism. An output transmission member, an input member which is disposed movably in the axial direction and is capable of moving forward by the drive source and pressing the output transmission member, and a first screw which is disposed movably in the axial direction and rotatable around the axis. An adjusting member engaged with the output transmitting member via a second screw mechanism having a reverse screw with the mechanism; a first clutch surface provided forward on the adjusting member; and a second clutch provided rearward on the input member. A clutch mechanism configured with a latching surface to restrain rotation of the adjusting member about the axis, and biasing the adjusting member in the forward direction with respect to the output transmission member so that when the first and second clutch surfaces are separated from each other. There is proposed a gap adjusting device for a disc brake device, comprising a biasing means for rotating an adjusting member relative to an output transmitting member.
[0010]
According to the above configuration, when the input member is advanced by the drive source to press the output transmission member in a state where the friction pad is worn, the piston connected to the output transmission member via the first screw mechanism defines the seal member. The vehicle moves forward while being elastically deformed, and generates a braking force by pressing the friction pad to engage with the brake disk. When the input member is retracted to the original position in order to release the braking force, the piston retracts only by the specified amount due to the elastic restoring force of the seal member. Therefore, the input member that is to be further retracted is connected thereto via the clutch mechanism. The piston is pulled rearward through the adjusted adjusting member, the output transmitting member connected to the adjusting member via the second screw mechanism, and the first screw mechanism provided on the adjusting member.
[0011]
As a result, the second screw mechanism slips, and the output transmission member relatively rotates with respect to the adjustment member and the piston which are non-rotatably restrained, whereby the piston is pushed forward by the first screw mechanism with respect to the output transmission member. 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 moving the input member forward again, the input member idles by the gap to separate the first and second clutch surfaces of the clutch mechanism, so that the second screw mechanism slips due to the urging force of the urging means. Then, the adjusting member advances with respect to the output transmission member, and the clutch mechanism is engaged again. By the above process, the piston advances by a part of the wear amount of the friction pad with respect to the output transmission member, and by repeating this, the total wear amount of the friction pad is finally adjusted.
[0012]
As described above, when the piston retreats, the first screw mechanism rotates to push the piston forward with respect to the output transmission member, and the amount of wear is adjusted. It is only a part of the amount, and by repeating this, the total amount of wear of the friction pad is finally adjusted, so excessive adjustment exceeding the wear amount of the friction pad when a large load is applied to the input member Can be prevented.
[0013]
In addition, since a driving source for rotation of the first and second screw mechanisms for adjusting the wear amount of the friction pad is not required, and the input member only has to be moved forward and backward in the axial direction, either the driving source of the hydraulic motor or the electric motor can be used. It can be applied to a disc brake device using, and versatility is improved. In addition, since a limiter mechanism and a one-way clutch, which are conventionally required, are not required, the structure can be simplified and the number of parts can be reduced.
[0014]
According to the second aspect of the present invention, in addition to the configuration of the first aspect, the gap adjusting device of the disc brake device is characterized in that the second screw mechanism has a rectangular thread and a thread groove. Suggested.
[0015]
According to the above configuration, since the second screw mechanism has the rectangular screw thread and the screw groove, the sliding friction resistance of the second screw mechanism can be reduced and smooth operation can be performed.
[0016]
According to a third aspect of the present invention, in addition to the configuration of the second aspect, a gap adjusting device for a disc brake device, wherein the second screw mechanism is made of synthetic resin or aluminum is proposed. You.
[0017]
According to the above configuration, since the second screw mechanism is made of a synthetic resin or aluminum, a rectangular screw thread and a screw groove can be easily manufactured by die molding.
[0018]
The brake disk 11 of the embodiment corresponds to the member to be braked 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 corresponds to The coil spring 36 of the embodiment corresponds to the driving source of the present invention, and corresponds to the urging means of the present invention.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0020]
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 of FIG. 1, and FIG. 3 is a line 3-3 in FIG. FIG. 4 is a sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a view showing a state of the input member when moving forward, FIG. 6 is a view showing a state of the input member moving backward, and FIG. FIG. 8 is a diagram showing a state at the start of re-advancement, FIG. 8 is a diagram showing a state during re-advancement of the input member, and FIG.
[0021]
As shown in FIGS. 1 to 4, in the electric brake device, a first friction pad 12 and a second friction pad 13 are arranged on both sides of a brake disk 11 that rotates together with the wheels so as to face each other. The second friction pads 12, 13 are composed of linings 12a, 13a that can contact the brake disc 11, and back plates 12b, 13b fixed to the back of the linings 12a, 13a. , 13b are movably supported by a bracket 14 fixed to the vehicle body 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 on the bracket 14 so as to be movable in the direction of the axis L.
[0022]
In this specification, the left side of the piston 28 in the direction of the axis L is defined as the front side, and the right side is defined as the rear side. Accordingly, a braking force is generated when the piston 28 advances to the left and presses the first friction pad 12, and the braking force is released when the piston 28 retreats to the right.
[0023]
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 15a and 15b are integrally connected by a bridging portion 15c passing through the outer peripheral portion of the brake disc 11.
[0024]
A substantially cylindrical input member 17 is slidably supported in the direction of the axis L by a guide hole 16 formed in the first pinching arm 15a. A large-diameter first rotor 18 and a small-diameter second rotor 19 are supported on the outer circumference of the input member 17 so as to be relatively rotatable. Balls 20 are arranged between the three (in the embodiment, three) cam grooves 18a, 19a. These cam grooves 18a, 19a and balls 20 constitute a ball-in ramp mechanism 40 of the present invention.
[0025]
An electric motor 22 is housed inside a motor holder 21 provided on the right side surface of the first pinching arm 15a, and its output shaft 22a is provided with a small-diameter first drive gear 23 and a large-diameter second drive gear 24. . The first drive gear 23 meshes with a first driven gear 18b formed on the outer periphery of the large-diameter first rotor 18, and the second drive gear 24 meshes with the second driven gear 19b 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 relatively. When the first rotor 18 and the second rotor 19 rotate relative to each other, the ball-in ramp mechanism 40 sandwiches the ball 20 between the cam grooves 18a of the first rotor 18 and the cam grooves 19a of the second rotor 19, The distance between the first rotor 18 and the second rotor 19 is increased.
[0026]
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 second The relative rotational speed between the two rotors 19 can be reduced, and the thrust force for widening the interval between the first and second rotors 18 and 19 can be increased. Therefore, a large thrust force can be generated by the electric motor 22 having a small size, a small output and a small power consumption without using a complicated gear train having a large reduction ratio or an electric motor having a large output. Power can be secured, and the number of parts, the number of assembly steps, the cost, and the size and weight of the electric disc brake device can be reduced.
[0027]
In addition, by reducing the difference in the number of teeth between the first drive gear 23 and the second drive gear 24 and ensuring a large reduction ratio, reverse transmission of drive force from the ball-in ramp mechanism 40 to the electric motor 22 is prevented. Since it is possible, it is not necessary to keep energizing the electric motor 22 while the braking force of a certain magnitude is being generated. That is, the electric power to the electric motor 22 only needs to be supplied when the braking force increases and when the braking force decreases, which can contribute to a reduction in power consumption. Therefore, this electric brake device is suitable for use as a parking brake other than the service brake.
[0028]
The right side surface of the second rotor 19 is supported by the first pinching arm 15a via a thrust washer 25, and its rightward movement is restricted. The input member 17 is biased rightward by a coil spring 26 disposed between the first flange 17a formed radially inward at the right end thereof and the first pinching arm 15a, so that the left end thereof is radially outwardly directed. The second flange 17b formed on the first rotor 18 is in contact with the left side surface of the first rotor 18 via the thrust washer 27. Therefore, when the distance between the first and second rotors 18 and 19 is increased by driving the electric motor 22, the input member 17 advances to the left with respect to the brake caliper 15 while compressing the coil spring 26.
[0029]
A piston 28 movably disposed on the axis L has a pressing portion 28a facing the rear 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 in a shape of a circle. An annular partition wall member 29 is fixed between the pressing portion 28a of the piston 28 and the second flange 17b of the input member 17 with a clip 30, and the outer peripheral surface of the partition wall member 29 has a first pinching arm via a seal member 31. 15a, and the inner peripheral surface slidably abuts the outer peripheral surface of the shaft portion 28b of the piston 28 via the seal member 32.
[0030]
As is clear from FIG. 2, the seal member holding groove 29a of the partition member 29 holding the seal member 32 has a gap 29b on the left side of the seal member 32 to prevent elastic deformation of the seal member 32 to the left. By allowing the seal member 32 to have no gap on the right side thereof, the elastic deformation of the seal member 32 to the right side is restricted.
[0031]
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 with the right end journal portion 34a meshes with a female screw formed on the inner periphery of the shaft portion 28b of the piston 28. To form 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.
[0032]
A cylindrical adjusting member 35 is fitted to the inner periphery of the input member 17 so as to be relatively rotatable. A female screw formed on the inner periphery of the adjusting member 35 and a large diameter portion 34b connected to the left side of the journal portion 34a of the output transmitting member 34 are formed. A second screw mechanism S2 is formed by meshing with a male screw formed on the outer periphery. The second screw mechanism S2 is a multi-thread (three in this embodiment) left-hand thread having a rectangular thread and a thread groove. That is, the turning directions of the thread and the groove of the first screw mechanism S1 and the second screw mechanism S2 are reversed.
[0033]
A coil spring 36 and a ball bearing 37 are arranged in series between a flange 35a protruding radially inward from the left end of the adjusting member 35 and a left end of the large diameter portion 34b of the output transmission member 34. The first clutch surface 35b at the left end of the adjustment member 35 is fixed to the inner peripheral surface of the input member 17 by the adjustment member 35 being urged leftward with respect to the output transmission member 34 by the elastic force of the coil spring 36. Abuts on the second clutch surface 38a on the right side of the clutch member 38 that has been used. The first clutch surface 35b and the second clutch surface 38a constitute a clutch mechanism 39 of the present invention.
[0034]
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 forming the output transmission member 34 and the adjustment member 35 from aluminum or synthetic resin, the rectangular screw thread and the screw groove 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, the molding cannot be performed due to the melting temperature of iron, and it is very costly to manufacture rectangular threads and thread grooves by cutting. Will increase.
[0035]
Next, the operation of the electric brake device having the above configuration will be described.
[0036]
First, a normal braking operation when the first and second friction pads 12, 13 are not worn will be described.
[0037]
In FIG. 2, when the electric motor 22 is driven to rotate forward to move the input member 17 to the left, the large-diameter portion 34b is pressed by the first flange 17a of the input member 17, and the output transmission member 34 moves to the left to output. The first friction pad 12 is pressed against one side surface of the brake disk 11 by the piston 28 having the shaft portion 28b meshing with the transmission member 34 via the first screw mechanism S1 moving forward to the left. Then, due to the reaction, the brake caliper 15 retreats to the right in the direction opposite to the forward direction of the piston 28, and the second pinching arm 15 b presses the second friction pad 13 against the other side of the brake disc 11. As a result, the first and second friction pads 12, 13 abut against both surfaces of the brake disc 11 with an equal surface pressure, and a braking force for braking the wheels is generated. At this time, the adjustment member 35 moves integrally with the input member 17 and the output transmission member 34.
[0038]
When the piston 28 advances to the left in this manner, the seal member 32 abutting on 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, 13 and the brake disc 11 is set so that the piston 32 does not slip with respect to the shaft portion 28b of the piston 28. .
[0039]
When the input member 17 is returned to the initial position by driving the electric motor 22 in the reverse direction from this state, the piston 28 retreats to the right by a 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 also retreat to the right so as to follow the input member 17. That is, when an appropriate pad clearance between the first and second friction pads 12 and 13 and the brake disc 11 is set, the stroke amount of the piston 28 moving forward to the left and the rollback moving backward to the right. The amount is consistent.
[0040]
A stopper (not shown) for regulating the first and second rotors 18 and 19 to the initial position is provided, and the first and second rotors 18 and 19 are regulated to the initial position by driving the electric motor 22 in the reverse direction. If the current 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.
[0041]
Next, the braking action when the first and second friction pads 12, 13 are worn will be described.
[0042]
When the electric motor 22 is driven to advance the input member 17 to the left from the state of FIG. 2 to the state of FIG. 5, if the first and second friction pads 12 and 13 are worn, the piston 28 Normally (when the first and second friction pads 12 and 13 are not worn), the pad clearance X, that is, a distance X + X ′ (X ′ is larger than the rollback amount X of the seal member 32, where X ′ is the first and second frictions). Since it advances to the left by the amount of wear of the pads 12 and 13), a slip equal to the amount of wear X 'occurs between the seal member 32 and the piston 28.
[0043]
When the electric motor 22 is rotated in reverse to release the braking, the input member 17 and the adjusting member 35 engaged with the input member 17 via the clutch mechanism 39 are moved by a distance X + X by the elastic force of the coil spring 26 as shown in FIG. ', The piston 28 and the output transmission member 34 can only retreat to the right by the rollback amount X of the seal member 32. This is because, even if the piston 28 attempts to retreat to the right side beyond the rollback amount X, an extremely large frictional force acting between the piston 28 and the seal member 32 restricts the retraction of the piston 28.
[0044]
In this way, when the adjusting member 35 tries to retreat to the right side by an amount X ′ of wear of the first and second friction pads 12 and 13 with respect to the output transmitting member 34, the rotation is caused by 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 restricted adjustment member 35. Since the piston 28 that meshes with the output transmission member 34 via the first screw mechanism S1 is restrained from rotating with respect to the first friction pad 12, the relative rotation between the output transmission member 34 and the piston 28 causes the piston 28 to rotate. 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-handed screw is drawn leftward by the distance Ldn with respect to the adjustment member 35 by relative rotation in the arrow R1 direction.
[0045]
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. The wear amount X ′ of the friction pads 12 and 13 is adjusted not for the entire amount but for a part except for the distance Ldn.
[0046]
Hereinafter, the above operation will be described quantitatively.
[0047]
The distance that the piston 28 advances to the left 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 with respect to the adjustment member 33 by one operation of the piston 28. Assuming that the distance to be performed is Ldn, the adjustment amount X ′ originally required (that is, the wear amount of the first and second friction pads 12 and 13) is:
X '= Lup + Ldn
Is represented by
[0048]
Here, assuming that 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
Is represented by
[0049]
Therefore, the ratio R of the amount adjusted by one operation of the piston 28 to the originally required adjustment amount X ′ is:

Is represented by
[0050]
As is clear from the above formula, 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 threads of the second screw mechanism S2 that are multi-threaded. It becomes bigger. Conversely, the ratio R becomes smaller as the pitch P1 of the first screw mechanism S1 that is a single-threaded screw is smaller, and as the pitch P2 and the number N of threads are larger in the second screw mechanism S2 that is a multi-threaded screw.
[0051]
Now, when the electric motor 22 is driven again from the state of FIG. 6 to move the input member 17 to the left, as shown in FIG. 7, the gap Ldn between the input member 17 and the output transmission member 34 disappears. The output transmission member 34, the adjustment member 35, and the piston 28 are moved to the left by being pushed by the input member 17. At this time, the input member 17 idles to the left by the gap Ldn, so that the leftward first clutch surface 35b of the adjusting member 35 and the rightward second clutch surface 38a of the clutch member 38 are separated by the distance Ldn. . Then, the adjusting member 35 urged to the left by the elastic force of the coil spring 36 slips in the direction of arrow R2 with respect to the output transmitting 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 screw thread and a screw groove with little frictional force, it slips smoothly and relatively rotates the adjusting member 35 and the output transmission member 34.
[0052]
Thereafter, when the piston 28 is further advanced by the electric motor 22, the first and second friction pads 12, 13 abut against the brake disc 11 to generate a braking force. When the electric motor 22 is driven in the reverse direction as shown in FIG. 9 to release the braking force from this state, the same operation as that of the first retreat of the piston 28 described in FIG. 6 is repeated, and the remaining unadjusted amount is used. Part of a certain distance Ldn is further adjusted. In this way, each time the piston 28 repeatedly advances and retreats, the initial wear amount X 'of the first and second friction pads 12, 13 is gradually adjusted, and finally the first and second friction pads 12, 13 are finally adjusted. And the pad clearance X between the brake discs 11 converges to the set value, that is, the normal stroke amount of the piston 28.
[0053]
If the electric motor 22 fails during the operation of the brake, a wrench is inserted into a hexagonal hole 34c formed at the right end of the output transmission member 34 and rotated to move the piston 28 backward and brake. Can be deactivated.
[0054]
As described above, only one 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 operation of the piston 28 is finally repeated by repeating the operation of the piston 28. 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 such that the distance between the first and second sandwiching arms 15a and 15b of the brake caliper 15 is increased, the second friction pad 12 and the third friction pad 12 and 13 can be used. 1, It is possible to prevent excessive adjustment exceeding the wear amount of the second friction pads 12 and 13. As a result, it is possible to abolish the over-adjustment prevention mechanism that was required conventionally, and it is possible to reduce the cost by simplifying the structure. Further, there is no need for a rotation drive source for the first and second screw mechanisms S1 and S2 for adjusting the wear of the first and second friction pads 12 and 13, and only by moving the input member 17 forward and backward in the direction of the axis L. Since the adjustment is performed, the present invention can be applied to a disc brake device using any of a hydraulic and an electric motor as a driving source, and versatility is improved.
[0055]
The embodiments of the present invention have been described above. However, various design changes can be made in the present invention without departing from the gist thereof.
[0056]
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, and the second screw mechanism S2 is a right-hand screw. It is good.
[0057]
In the embodiment, the electric motor exemplifies the disc brake device using the electric motor 22 as a drive source. However, the present invention can be applied to a disc brake device using a hydraulic pressure or a cable as a drive source.
[0058]
【The invention's effect】
According to the invention described in claim 1 as described above, after the piston advances and presses the friction pad against the brake disc to generate a braking force, when the piston retreats to release the braking force, The rotation of the first screw mechanism pushes the piston forward with respect to the output transmission member to adjust the amount of wear. The amount of adjustment is only a part of the amount of wear of the friction pad, and this is repeated. In this way, since the total amount of wear of the friction pad is finally adjusted, it is possible to prevent excessive adjustment exceeding the wear amount of the friction pad when a large load is applied to the input member.
[0059]
Further, since there is no need for a driving source for rotation of the first and second screw mechanisms for adjusting the wear amount of the friction pad, and since the input member may be moved forward and backward in the axial direction, any of the driving sources of the hydraulic and electric motors can be used. It can be applied to a disc brake device using, and versatility is improved. In addition, since a limiter mechanism and a one-way clutch, which are conventionally required, are not required, the structure can be simplified and the number of parts can be reduced.
[0060]
According to the second aspect of the present invention, since the second screw mechanism has a rectangular thread and a thread groove, the sliding frictional resistance of the second screw mechanism is reduced to enable smooth operation. Can be.
[0061]
According to the third aspect of the present invention, since the second screw mechanism is made of synthetic resin or aluminum, a rectangular screw thread and a screw groove can be easily manufactured by die molding.
[Brief description of the drawings]
1 is a cross-sectional view of the electric disc brake device; FIG. 2 is an enlarged view of a part of FIG. 1; FIG. 3 is a cross-sectional view taken along a line 3-3 in FIG. 2; FIG. FIG. 5 is a diagram illustrating a state of the input member when the input member is advanced. FIG. 6 is a diagram illustrating a state of the input member when the input member is retracted. FIG. FIG. 9 is a diagram showing a state during re-forwarding. FIG. 9 is a diagram showing a state when the input member is retreating again.
11 Brake disc (member to be braked)
12 First friction pad (braking member)
13 Second friction pad (braking member)
17 Input member 22 Electric motor (drive source)
28 Piston 32 Seal member 34 Output transmission member 35 Adjustment member 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 (3)

A piston (28) movably arranged in the direction of the axis (L) to engage the friction pads (12, 13) with the brake disc (11);
A sealing member (32) for elastically deforming by a frictional force when the piston (28) advances, and for retracting the advanced piston (28) by a specified amount by the elastic restoring force;
An output transmission member (34) that is arranged to be movable in the direction of the axis (L) and rotatable about the axis (L) and engages the piston (28) via the first screw mechanism (S1);
An input member (17) movably arranged in the direction of the axis (L) and capable of moving forward by the drive source (22) and pressing the output transmission member (34);
It is arranged to be movable in the direction of the axis (L) and rotatable about the axis (L), and is engaged with the output transmission member (34) via the first screw mechanism (S1) and the second screw mechanism (S2) of reverse screw. An adjusting member (35) to be combined;
An axis (L) of the adjusting member (35), comprising a first clutch surface (35b) provided forward on the adjusting member (35) and a second clutch surface (38a) provided rearward on the input member (17). A clutch mechanism (39) for restraining the rotation around;
The adjusting member (35) is biased in the forward direction with respect to the output transmitting member (34), and when the first and second clutch surfaces (35b, 38a) are separated from each other, the adjusting member (35) is adjusted with respect to the output transmitting member (34). Biasing means (36) for relatively rotating (35);
A gap adjusting device for a disc brake device, comprising: The gap adjusting device for a disk brake device according to claim 1, wherein the second screw mechanism (S2) has a rectangular thread and a thread groove. The disc brake device according to claim 2, wherein the second screw mechanism (S2) is made of synthetic resin or aluminum.

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