JP2004324804A - Electrically powered brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a structure of a reduction gear mechanism used for a ball-in-ramp mechanism of an electrically powered brake device. <P>SOLUTION: The electrically powered brake device is provided with a first disk 18 having a first driven gear 18b engaged with a first drive gear 23 which is arranged on the output shaft 22a of an electric motor 22, and a second disk 19 having a second driven gear 19b engaged with a second drive gear 24 which is arranged on the output shaft 22a. A gear ratio between the first drive gear 23 and the first driven gear 18b, and a gear ratio between the second drive gear 24 and the second driven gear 19b, are set to be different each other. The ball-in-ramp mechanism 40 driving a piston 28 pushing a friction pad 12 is arranged between the first disk 18 and the second disk 19. An excessively large reduction ratio is obtained so that difference between the number of gear teeth of the first and the second drive gears 23 and 24 is set to be small. Therefore, even though the small, lightweight electric motor 22 is employed, enough braking force can be obtained by driving the ball-in-ramp mechanism 40 with large torque. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

で表される。
【００４２】
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。
【００４３】
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。
【００４４】
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。
【００４５】
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。
【００４６】
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。
【００４７】
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。
【００４８】
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。
【００４９】
【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、電動モータの出力軸に設けた第１、第２駆動ギヤに、ボールインランプ機構を作動させる第１、第２部材に設けた第１、第２従動ギヤを噛み合わせて減速機構を構成したので、第１、第２駆動ギヤの歯数差を小さく設定することで極めて大きな減速比を得ることができ、小型軽量の電動モータを採用しても大きなトルクでボールインランプ機構を作動させて充分な制動力を得ることができる。しかも僅かに４個のギヤで減速機構を構成できるので、小型軽量の電動モータを採用できることと相まって、電動ブレーキ装置の小型軽量化およびコストの削減が可能になる。
【００５０】
また減速機構の減速比を大きくできるので、ボールインランプ機構側から電動モータ側に駆動力が逆伝達されることがなく、従って制動中に電動モータへの通電を断っても制動力を保持することができ、特に駐車ブレーキとして使用する場合に電力消費量を削減することができる。
【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）
１８ 第１ロータ（第１部材）
１８ｂ 第１従動ギヤ
１９ 第２ロータ（第２部材）
１９ｂ 第２従動ギヤ
２２ 電動モータ
２２ａ 出力軸
２３ 第１駆動ギヤ
２４ 第２駆動ギヤ
４０ ボールインランプ機構
Ｌ 軸線[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electric brake device provided with a ball-in ramp mechanism that converts a rotational force of an electric motor into an axial thrust and presses a braking member against a member to be braked by the thrust to generate a braking force.
[0002]
[Prior art]
Such an electric brake device is known, for example, from the following patent document. In this electric brake device, a ball-in ramp mechanism and an electric motor are arranged in series on the axis of a piston that presses a braking member, and a rotor of the electric motor is directly connected to a rotating disk of the ball-in ramp mechanism. By rotating the rotating disk, a ball-in ramp mechanism is operated to drive the piston.
[0003]
[Patent Document]
JP 2000-346109 A
[Problems to be solved by the invention]
However, in the above conventional motor, since the rotor of the electric motor is directly connected to the rotating disk of the ball-in ramp mechanism, it is necessary to provide a large electric motor having a large output torque to generate sufficient thrust on the piston. There is a problem that the entire electric brake device becomes large.
[0005]
When a small electric motor with a small output torque is used, it is necessary to reduce the rotation of the output shaft at a large reduction ratio and transmit the rotation to the rotating disk of the ball-in ramp mechanism, which requires a large number of parts. A large reduction gear is required, which may lead to an increase in the size of the entire electric brake device and an increase in cost.
[0006]
The present invention has been made in view of the above circumstances, and has as its object to simplify the structure of a speed reduction mechanism of a ball-in ramp mechanism of an electric brake device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the invention described in claim 1, the rotational force of the electric motor is converted into an axial thrust, and the braking force is pressed against the member to be braked by the thrust to reduce the braking force. In an electric brake device provided with a ball-in ramp mechanism for generating, a first member having a first driven gear meshing with a first drive gear provided on an output shaft of an electric motor, and a second drive provided on an output shaft of the electric motor. A second member having a second driven gear meshing with the gear is provided so that a gear ratio between the first driving gear and the first driven gear and a gear ratio between the second driving gear and the second driven gear are different; An electric brake device is proposed, wherein a ball-in ramp mechanism is arranged between one member and a second member.
[0008]
According to the above configuration, the first and second driven gears provided on the first and second members for operating the ball-in ramp mechanism mesh with the first and second drive gears provided on the output shaft of the electric motor. Since the reduction mechanism is configured, an extremely large reduction ratio can be obtained by setting the difference in the number of teeth between the first and second drive gears to be small, and the ball-in ramp can be provided with a large torque even when a small and lightweight electric motor is employed. By operating the mechanism, a sufficient braking force can be obtained. In addition, since the speed reduction mechanism can be configured with only four gears, a small and lightweight electric motor can be employed, and the size and weight of the electric brake device can be reduced, and the cost can be reduced.
[0009]
Also, since the speed reduction ratio of the speed reduction mechanism can be increased, the driving force is not reversely transmitted from the ball-in ramp mechanism side to the electric motor side. Therefore, the braking force is maintained even when the power supply to the electric motor is stopped during braking. Power consumption can be reduced, especially when used as a parking brake.
[0010]
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 first rotor 18 of the embodiment. And the second rotor 19 respectively correspond to the first member and the second member of the present invention.
[0011]
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.
[0012]
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.
[0013]
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.
[0014]
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.
[0015]
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.
[0016]
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.
[0017]
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.
[0018]
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.
[0019]
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.
[0020]
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.
[0021]
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.
[0022]
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.
[0023]
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.
[0024]
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.
[0025]
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.
[0026]
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.
[0027]
Next, the operation of the electric brake device having the above configuration will be described.
[0028]
First, a normal braking operation when the first and second friction pads 12, 13 are not worn will be described.
[0029]
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.
[0030]
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. .
[0031]
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.
[0032]
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.
[0033]
Next, the braking action when the first and second friction pads 12, 13 are worn will be described.
[0034]
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.
[0035]
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.
[0036]
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.
[0037]
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.
[0038]
Hereinafter, the above operation will be described quantitatively.
[0039]
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
[0040]
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
[0041]
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
[0042]
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.
[0043]
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.
[0044]
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.
[0045]
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.
[0046]
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.
[0047]
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.
[0048]
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.
[0049]
【The invention's effect】
As described above, according to the first aspect of the present invention, the first and second drive gears provided on the output shaft of the electric motor are provided on the first and second members for operating the ball-in ramp mechanism. Since the first and second driven gears mesh with each other to form a speed reduction mechanism, an extremely large reduction ratio can be obtained by setting the difference in the number of teeth between the first and second drive gears to be small, and a small and light electric motor can be obtained. Even if it is adopted, a sufficient braking force can be obtained by operating the ball-in ramp mechanism with a large torque. In addition, since the speed reduction mechanism can be configured with only four gears, a small and lightweight electric motor can be employed, and the size and weight of the electric brake device can be reduced, and the cost can be reduced.
[0050]
Also, since the speed reduction ratio of the speed reduction mechanism can be increased, the driving force is not reversely transmitted from the ball-in ramp mechanism side to the electric motor side. Therefore, the braking force is maintained even when the power supply to the electric motor is stopped during braking. Power consumption, especially when used as a parking brake.
[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)
18 First rotor (first member)
18b First driven gear 19 Second rotor (second member)
19b Second driven gear 22 Electric motor 22a Output shaft 23 First drive gear 24 Second drive gear 40 Ball-in ramp mechanism L Axis

Claims (1)

A ball-in ramp mechanism that converts the rotational force of the electric motor (22) into a thrust in the direction of the axis (L) and presses the braking members (12, 13) against the member to be braked (11) with the thrust to generate a braking force. In the electric brake device provided with (40),
A first member (18) having a first driven gear (18b) meshing with a first drive gear (23) provided on an output shaft (22a) of the electric motor (22); and an output shaft (22a) of the electric motor (22). And a second member (19) having a second driven gear (19b) meshing with the second driving gear (24) provided in the first driving gear (23) and the first driven gear (18b). And a gear ratio between the second drive gear (24) and the second driven gear (19b) and a ball-in ramp mechanism (40) between the first member (18) and the second member (19). ) Is arranged, the electric brake device.

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