JP2007056917A - Electric disk brake - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric disk brake which is actually mounted on a vehicle while contact of a pad and a disk rotor by tension of a harness is prevented. <P>SOLUTION: In the electric disk brake, an electric motor 3 is equipped with a first motion conversion means (a piston 13 and a ball screw mechanism 17), for compulsory displacing an inner pad 1a to the disk rotor 2, fixed so as not to change position for an axle 8 in a wheel shaft direction, converts rotational motion of a rotational shaft of the electric motor 3 into a linear motion in the wheel shaft direction, a bridge 6, which can be relatively displaced to the axle 8 in the wheel shaft direction, for displacing an outer pad 1b to the disk rotor 2 and a second motion conversion means (ball bearings 15e, 15f and the ball screw mechanism 17) for converting rotational motion of a rotation shaft of the electric motor 3 into a linear motion in the wheel shaft direction and displacing the bridge 6 in a direction for compulsory displacing the outer pad 1b to the disk rotor 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of an electric disc brake that sandwiches a disc rotor between an inner pad and an outer pad and applies a braking force to a wheel.

  Conventional electric disc brakes have a hydraulic piston only on the inner side called the fist type of a hydraulic disc brake. Instead of pressing the piston with hydraulic pressure, the piston is moved according to the amount of rotation of the electric motor. The inner pad is pressed against the disc rotor, and the piston is moved in a direction opposite to the moving direction of the inner pad by the pressing reaction force, thereby pressing the outer pad against the disc rotor.

A harness is provided between the electric motor and the vehicle body side (for example, an axle) to supply power, control signals, and the like from the vehicle body side to the electric motor. In addition, since the braking force of an automobile needs to be enough to stop a private vehicle having a weight of 1 to 2 tons, a considerably large force is required, and the electric motor power is increased by a speed reducer. Requires considerable current. In addition, if the electrical resistance of the harness is large, energy is lost due to the resistance, so that a harness having a considerably large diameter is used as compared with general home appliances (for example, , See Patent Document 1).
JP 2000-55093 A

  By the way, in the case of the hydraulic type, the brake hose that transmits the hydraulic pressure between the caliper and the vehicle body is made of rubber and the material that enters the hose is liquid even if it is a fist type. The tension is weak so that the caliper does not move and the pad does not come into contact with the rotor.

  However, in the above prior art, since the electric motor is a floating type disc brake that moves integrally with the cylinder, the harness fixing end of the vehicle body constantly moves up and down and the brake pad wears when the suspension slides. As it advances, the initial position of the piston changes, and the reaction force of the harness is input to the electric motor in accordance with the tension of the hard harness. As a result, the relative position between the vehicle body and the electric motor (caliper) changes, and the pad moves and comes into contact with the disk rotor and drag occurs even though the electric motor does not generate the pressing force of the pad. There was a problem.

  In the case of the hydraulic type, there is an opposed piston type in addition to the fist type. In this type, the caliper body does not have a part that moves in the piston axial direction with respect to the vehicle body side. Does not occur. However, even if this opposed piston type is applied to the electric disc brake, since the electric motor is attached to the piston in the case of the electric type, when the motor is provided on both the inner caliper side and the outer caliper side, the outer side is the tire wheel. It does not hold because of interference.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide an electric disc brake that can be actually mounted on a vehicle while preventing contact between the pad and the disc rotor due to the tension of the harness. It is to provide.

In order to achieve the above object, the present invention provides:
In the electric disc brake that presses the inner pad and the outer pad that are arranged opposite to each other by the driving force of the electric motor against the disc rotor to brake the wheel,
The electric motor is fixed to the vehicle body side member in a position invariant in the wheel axis direction,
A first motion converting means for converting the rotational motion of the rotating shaft of the electric motor into a linear motion in a wheel axis direction, and forcibly displacing the inner pad with respect to the disk rotor;
A bridge portion that is displaceable relative to the vehicle body side member in a wheel axis direction, and that displaces the outer pad relative to the disk rotor;
A second motion converting means for converting the rotational motion of the rotating shaft of the electric motor into a linear motion in a wheel axis direction, and displacing the bridge portion in a direction in which the outer pad is forcibly displaced with respect to the disk rotor;
It is characterized by providing.

  Therefore, in the present invention, since the electric motor is fixed to the vehicle body side member in the position in the direction of the wheel axis, even when the harness reaction force is input to the electric motor, the relative position between the vehicle body and the electric motor is It is possible to prevent the pads from coming into contact with the disk rotor without changing. Further, since the first motion conversion means and the second motion conversion means for forcibly converting the rotational motion of the motor rotation shaft into the linear motion of the inner pad and the outer pad, respectively, only one electric motor fixed to the vehicle body side member is used. Thus, an electric disc brake in which the disc rotor is sandwiched between two pads can be realized. As a result, it is possible to provide an electric disc brake that can be practically mounted on a vehicle while preventing contact between the pad and the disc rotor due to the tension of the harness.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 and 2.

First, the configuration will be described.
1 is a bottom view of the electric disc brake A according to the first embodiment, FIG. 2 is a plan view of the electric disc brake A, FIG. 3 is a right side view of the electric disc brake A, and FIG. 5 is a front view of the electric disc brake A, and FIG. 6 is a rear view of the electric disc brake A.

  The electric disc brake A according to the first embodiment sandwiches the disc rotor 2 between the inner pad 1a and the outer pad 1b that are arranged to face each other, and applies braking force to the wheels. The electric motor 3, the linear drive converter 4, The torque member 5 and a bridge (bridge portion) 6 are provided.

  The electric motor (hereinafter, referred to as a motor) 3 is fixed to the axle 8 that is a vehicle body side member so as to remain in the position in the wheel axis direction. The motor 3 is connected to a harness 7 that connects a power supply source of the vehicle and an ECU (not shown) that generates a brake control signal. The harness 7 includes a portion that supplies drive power from a battery installed in the vehicle to the motor 3 and a portion that includes a control signal line that detects a brake operation amount and communicates a control amount of the motor 3.

  The linear drive converter 4 converts the rotary motion of the rotary shaft of the motor 3 into a linear motion in the wheel axis direction, forcibly displaces the inner pad 1a with respect to the disc rotor 2, and the rotary motion of the rotary shaft of the motor 3 to the wheel. The bridge 6 is displaced in a direction in which the outer pad 1b is forcibly displaced with respect to the disk rotor 2 by converting into linear motion in the axial direction.

  The torque member 5 is for fixing the electric disc brake A to the vehicle body side, and is bolted to the axle 8 by an axle fitting bolt 5a.

  The bridge 6 displaces the outer pad 1b with respect to the disc rotor 2, supports the outer pad 1b, and is supported so as to be relatively movable in the wheel axis direction with respect to the torque member 5. Radiating fins 9 are provided on the back side and the left and right side surfaces of the bridge 6. The radiating fins 9 are arranged along the flow of air generated during traveling. The bridge 6 is provided with a pad slide guide 21 that restricts rotation of the inner pad 1a, the outer pad 1b, and the bridge 6 around the wheel axis direction and guides movement in the wheel axis direction.

Next, the internal structure of the electric disc brake A will be described.
An ECU cover 10 a to which the harness 7 is fixed is provided on the back surface of the torque member 5. The harness 7 is connected to the ECU 10 built in the ECU housing 10c in a fixed relationship by the ECU cover 10a and a plurality of ECU cover screws 10b.

  The ECU 10 supplies the motor 3 with a power supply signal that supplies a driving force source for the motor 3. The motor 3 includes a motor cover 3a fixed to the torque member 5, a motor stator 3b fixed in the motor cover 3a, and a motor rotor 3c. The ECU 10 is connected to the motor stator 3b. The output of the motor rotor 3c is transmitted to the main shaft 14 provided integrally with the motor rotor 3c.

  Further, the ECU 10 receives an output signal from the resolver 11. The resolver 11 includes a resolver stator 11a fixed to the ECU housing 10c, and a resolver rotor 11b that rotates integrally with a main shaft 14 described later.

  The main shaft 14 is rotatably supported via ball bearings 15a and 15b with respect to the motor cover 3a and the ECU housing 10c. The output of the main shaft 14 is transmitted to the planetary gear 12. A groove 14a is formed at the end of the main shaft 14 on the ECU 10, and a latch mechanism 20 that is driven by a solenoid is set facing the groove 14a. For example, the latch mechanism 20 is operated when a pressing force is continuously generated as in parking, and the rotation of the main shaft 14 is fixed, so that the motor 3 is driven even when the motor 3 is not energized. This is for holding the rotational driving force.

  The planetary gear 12 decelerates the output of the main shaft 14 and outputs it to the input gear 16. The ring gear 121 fixed to the torque member 5 and the pinion that rotates while meshing with the ring gear 121 according to the rotation of the main shaft 14. 122. The pinion 122 has a first gear stage 122 a that meshes with the ring gear 121 and a second gear stage 122 b that meshes with the input gear 16. The input gear 16 is rotatably supported via the torque member 5 and ball bearings 15c and 15d, and transmits the output of the planetary gear 12 to the linear drive converter 4.

  The linear drive converter 4 includes a piston (piston member) 13, ball bearings (rotating sliding portions) 15 e and 15 f, and a ball screw mechanism (piston motion conversion mechanism and bridge portion motion conversion mechanism) 17. Yes. The piston 13 and the ball screw mechanism 17 constitute a first motion converting means for converting the rotational motion of the rotating shaft of the electric motor 3 into a linear motion in the wheel axis direction and forcibly displacing the inner pad 1a with respect to the disc rotor 2. . Further, the ball bearings 15e and 15f and the ball screw mechanism 17 convert the rotational motion of the rotating shaft of the electric motor 3 into linear motion in the wheel axis direction, and the bridge 6 is forced to displace the outer pad 1b relative to the disc rotor 2. A second motion conversion means for displacing is configured.

  The ball screw mechanism 17 includes a ball screw nut 17a, a ball 17b, and a ball screw screw 17c. The ball screw nut 17a is supported by the bridge 6 via ball bearings (bearing members) 15e and 15f, and is coupled to be rotatable relative to each other and not movable relative to the wheel shaft direction. The ball screw nut 17a is spline-coupled to the input gear 16, and is connected to the input gear 16 so as to be relatively movable in the wheel axis direction and to be integrally rotatable.

  The piston 13 is provided integrally with the inner pad 1a, and a ball screw screw 17c is formed at a position near the motor 3 on the outer periphery, and a sliding contact portion 13a is formed at a position near the inner pad 1a. The sliding contact portion 13a is set to have a larger diameter than the outer diameter of the ball screw screw 17c, and slides on the cylinder surface 6a formed on the inner periphery of the bridge 6 when the piston 13 moves linearly. In addition, a gap is set between the sliding contact portion 13a and the ball bearing 15e to avoid the ball bearing 15e from contacting the piston 13a. From the piston 13 that becomes high temperature during braking to the ball bearing 15e. Direct heat transfer is avoided.

  Between the sliding contact portion 13a and the cylinder surface 6a, a seal 18a is set to prevent dust from being mixed and the internal lubricant from flowing out. Further, the piston 13 is provided with a stopper 19 that prevents the inner pad 1a from falling off the bridge 6 during braking.

  Between the bridge 6 and the torque member 5, a seal 18 b is set to prevent dust from entering and internal lubricant from flowing out. The seal material, seal width, and crushing allowance are set so that the seal 18b has the same sliding resistance as the seal 18a.

Next, the operation will be described.
[Brake force generation action]
The ECU 10 supplies a drive current to the motor stator 3b according to the brake operation amount of the driver. With this current supply, the motor stator 3b generates a rotational driving force with the motor rotor 3c, and rotates the main shaft 14 provided integrally with the motor rotor 3c.

  The rotation of the main shaft 14 is decelerated by the planetary gear 12, and then transmitted from the input gear 16 to the ball screw nut 17a, whereby the ball screw nut 17a rotates. Here, when the operating resistance (sliding resistance or the like) of the piston 13 is smaller than the operating resistance of the ball screw nut 17a, the ball screw nut 17a rotates without changing its position in the wheel axis direction. Therefore, the rotation of the ball screw nut 17 a is converted into a linear motion of the piston 13 by the ball screw mechanism 17, and the inner pad 1 a is pressed against the disc rotor 2.

  When the piston 13 receives a reaction force from the disk rotor 2 and the operating resistance of the piston 13 becomes larger than the operating resistance of the ball screw nut 17a, the piston 13 stops linear movement, but the ball screw nut 17a On the other hand, since it is connected so as to be relatively movable in the wheel axis direction, linear movement is started toward the motor 3 side in the wheel axis direction while rotating by the driving force of the motor 3. The linear motion of the ball screw nut 17a is transmitted to the bridge 6 via the ball bearing 15f, and the outer pad 1b provided integrally with the bridge 6 is pressed against the disc rotor 2.

  When the bridge 6 receives a pressing reaction force from the disk rotor 2 and the operating resistance of the piston 13 becomes smaller than the operating resistance of the ball screw nut 17a, the inner pad 1a is again pressed against the disk rotor 2 by the linear movement of the piston 13. That is, the above operation is repeated according to the motor driving force, and the frictional force is finally generated against the rotor friction surfaces 2a and 2b of the disk rotor 2 by the reaction force generated by the inner pad 1a and the outer pad 1b. A braking force is applied to the wheels. This braking force is controlled according to the motor output current detected by the ECU 10 and the motor rotation amount detected by the resolver 11.

  After the above operation, when the driver removes his / her foot from the brake pedal, the ECU 10 reverses the rotation direction of the motor 3. As a result, the piston 13 and the ball screw nut 17a linearly move in the direction of the wheel axis opposite to that during braking from the smaller operating resistance, and the inner pad 1a and the outer pad 1b are finally separated from the disk rotor 2.

  Here, when the disc rotor 2 is worn and the initial position of the piston 13 is changed, the initial position of the piston 13 is corrected by correcting the deviation of the rotation amount due to the initial rotation position of the resolver 11 and the pad wear amount. change. Since the piston 13 is provided with the stopper 19, it is possible to prevent the piston 13 from dropping from the bridge 6 when the inner pad 1a is replaced.

  During braking, the frictional heat generated on the rotor friction surfaces 2a and 2b is transmitted to the outer pad 1b and the inner pad 1a, and the amount of heat transmitted to the outer pad 1b is released to the atmosphere by the radiation fins 9 installed on the bridge 6. . On the other hand, the amount of heat transmitted to the inner pad 1 a is transmitted to the piston 13, most of which is transmitted to the bridge 6 in contact with the sliding contact portion 13 a, and is released to the atmosphere by the radiation fins 9.

[Dragging due to harness reaction force]
Japanese Patent Laid-Open No. 2000-55093 discloses a floating type electric motor that generates a braking force by converting rotation of a rotor of a DC servo motor into linear motion of a piston by a nut member and pressing a brake pad against a disk rotor. Disc brakes are listed.

  In this electric disc brake, the caliper body is supported by a carrier so as to be movable along the axial direction of the disc rotor. Then, by moving the piston forward and pressing one brake pad against the sliding surface on one side of the disk rotor, the caliper body is moved by the reaction force, and the other brake pad is moved to the other side of the disk rotor by the claw portion. Pressed against the sliding surface to generate braking force.

  As shown in FIG. 7, the electric disc brake requires a braking force for stopping a vehicle having a vehicle weight of 1 to 2 tons. Therefore, a considerable current is required for the electric motor. In addition, if the electrical resistance of the harness is large, energy is lost due to the resistance, so that a harness having a considerably large diameter is used as compared with general home appliances.

  As described above, in the case of a floating type disc caliper, the harness connects the electric disc brake disposed near the wheel (axle) and the vehicle body, so that the electric disc brake and the vehicle are fixed by sliding the suspension. The relative position with the edge constantly changes. Further, when the brake pads are worn, movement occurs between the electric disc brake and the axle that fixes the electric disc brake. At this time, a reaction force due to the harness is generated according to the amount of movement, and a pressing force is generated on the disc rotor along the carrier that allows the caliper body to move freely in the disc rotor axial direction.

  For the above reasons, the electric disc brake receives a force from the harness, and the disc rotor and caliper come into contact with each other to generate drag. This drag causes Shimmy Judder.

[Drag prevention]
On the other hand, in the electric disc brake A of the first embodiment, the housing (torque member 5 + motor cover 3a + ECU cover 10a), the motor 3 in the housing portion, the ECU 10 that controls the motor 3, the vehicle body, and the ECU 10 are connected. The connection part of the harness 7 was fixed to the axle 8 on the vehicle body side.

  That is, the reaction force of the harness 7 generated by the sliding of the suspension is input to the axle 8 after being input to the housing (torque member 5 + motor cover 3a + ECU cover 10a). There is no moving to. Further, since the bridge 6 and the piston 13 are installed so as to be movable in a direction facing the housing, the housing does not need to move relative to the axle 8 even when the inner pad 1a and the outer pad 1b are worn. The relative positional relationship between the connecting portion of the vehicle 7 and the vehicle does not change, and the reaction force from the harness 7 is not input.

  In the first embodiment, the linear drive converter 4 that converts the rotational force of the motor 3 into linear motion and forcibly displaces the inner pad 1a and the outer pad 1b relative to the disk rotor 2 is provided. An electric disc brake in which the disc rotor 2 is sandwiched between the two pads 1a and 1b can be realized using only one electric motor fixed to the disc.

  That is, in the conventional floating type disc brake in which the electric motor and the outer pad are integrally provided, when the driver stops the brake operation, the inner pad is pulled to the pull side (disc It is possible to move in a direction away from the rotor. However, since the displacement of the outer pad depends on the disk rotor pressing reaction force of the inner pad, the movement toward the pulling side stops when the pressing reaction force is no longer input to the inner pad. Therefore, even after the brake is released, the outer pad comes into contact with the disk rotor, and dragging may occur.

  On the other hand, in the first embodiment, the outer pad 1b can be forcibly displaced with respect to the disk rotor 2 on both the pushing side and the pulling side, so that drag due to contact between the outer pad 1b and the disk rotor 2 can be prevented.

  In the first embodiment, since the sliding resistance of the seal 18a set between the piston 13 and the bridge 6 and the seal 18b set between the bridge 6 and the torque member 5 are set to be the same, the inner pad 1a Since the frictional force is biased to one of the outer pads 1b, the positions of the inner pad 1a and the outer pad 1b are biased, and the occurrence of drag can be avoided.

[Heat resistant load suppression effect of ball bearing]
In the disc brake, the piston that pushes and pulls the inner pad becomes high temperature due to heat transfer from the inner pad and the outer pad due to frictional heat generated between the disc rotor and the inner pad and the outer pad. Therefore, when a piston and a bearing member such as a bearing that receives the thrust are close to each other, it is necessary to select one having high heat resistance against the bearing.

  Therefore, as in the first embodiment, by interposing the ball screw mechanism 17 having a large heat capacity between the ball bearings 15e, 15f and the piston 13, a large amount of heat transmitted from the piston 13 to the ball screw nut 17a can be obtained. The ball screw mechanism 17 can be released into the atmosphere, and the heat resistance load of the ball bearings 15e and 15f can be reduced.

  Further, in the first embodiment, the piston 13 is provided with a sliding contact portion 13a that is in sliding contact with the bridge 6, and the ball bearings 15e and 15f are disposed between the ball screw nut 17a and the bridge 6 and more than the sliding contact portion 13a. The piston 13 was disposed so as not to contact the piston pad 13 at a position away from the inner pad 1a. As a result, most of the heat transmitted from the inner pad 1a to the piston 13 can be released from the sliding contact portion 13a to the bridge 6 having a large heat capacity, and the heat is directly transmitted from the piston 13 to the ball bearings 15e and 15f. Can be avoided, and the heat resistance load of the ball bearings 15e and 15f can be further reduced.

[Miniaturization of piston]
When the inner pad 1a is worn, when braking is performed with the piston 13 protruding, the cylinder surface 6a needs to have a strength when the cylinder surface 6a receives a moment applied to the piston 13, and the piston 13 There is a problem that the wall thickness of 13 and the bridge 6 is increased. In the first embodiment, the moment applied to the piston 13 can be received by the ball bearing 15f located far from the cylinder surface 6a with respect to the inner pad 1a, and the moment force that the piston 13 itself takes can be reduced. 13 can be miniaturized.

[Heat radiation action by heat radiation fins]
In the electric disc brake described in Japanese Patent Laid-Open No. 2000-55093, the frictional heat is transmitted to the bearing through the bridge, whereas in the electric disc brake A according to the first embodiment, the disc rotor during braking is used. On the heat transfer path from 2 to the ball bearings 15e and 15f, the radiating fins 9 are provided on the bridge 6 that is located upstream of the ball bearings 15e and 15f.

  That is, the heat generated by the disk rotor 2 is transmitted to the bridge 6 and the piston 13 via the inner pad 1a and the outer pad 1b. The sliding contact portion 13a of the piston 13 is in a sliding relationship with the bridge 6, and heat is radiated by the heat radiating fins 9 in order to allow heat transfer. Therefore, the amount of heat transmitted from the piston 13 to the ball bearings 15e and 15f via the bridge 6 and the amount of heat transmitted from the bridge 6 to the ECU 10 side via the torque member 5 can be suppressed, and the ball bearings 15e and 15f and It becomes possible to reduce the heat load of ECU10. Moreover, in Example 1, since the radiation fin 9 was installed in the direction along the flow of the air generated when the vehicle travels, the traveling wind easily passes through during travel, and the heat radiation effect of the radiation fin 9 is further enhanced.

Next, the effect will be described.
In the electric disc brake of the first embodiment, the effects listed below can be obtained.

  (1) In the electric disc brake A that presses the inner pad 1a and the outer pad 1b that are arranged to face each other by the driving force of the electric motor 3 against the disc rotor 2 to brake the wheel, the electric motor 3 is in the wheel axis direction with respect to the axle 8. A first motion conversion means for converting the rotational motion of the rotating shaft of the electric motor 3 into a linear motion in the wheel axis direction and forcibly displacing the inner pad 1a with respect to the disc rotor 2; Relative displacement is possible in the wheel axis direction, the bridge 6 that displaces the outer pad 1b with respect to the disk rotor 2, and the rotational movement of the rotating shaft of the electric motor 3 is converted into linear movement in the wheel axis direction, and the outer pad 1b is converted into the disk rotor 2 And a second motion conversion means for displacing the bridge 6 in the direction of forced displacement. Therefore, it is possible to provide an electric disc brake that can be practically mounted on a vehicle while preventing contact between the pads 1a and 1b and the disc rotor 2 due to the tension of the harness 7.

  (2) The first motion conversion means rotates integrally with the rotating shaft of the electric motor 3 and can move relative to the motor rotating shaft in the axial direction, and the rotational motion of the piston 13 as the piston 13 rotates. A ball screw mechanism 17 for converting the linear screw motion into a linear motion, and the second motion converting means includes a rotary sliding portion that allows the rotary motion of the ball screw nut 17a even when the linear motion of the piston 13 is restricted, And a ball screw mechanism 17 that converts the rotational motion of the rotating shaft of the electric motor 3 into the linear motion of the bridge 6 in the wheel axis direction when the linear motion of the piston 13 is restricted. Therefore, the first and second motion converting means for forcibly displacing the inner pad 1a and the outer pad 1b to both the pushing side and the pulling side with respect to the disk rotor 2 by using one electric motor 3 is realized with a simple configuration. it can.

  (3) Since the rotary sliding portions are ball bearings 15e and 15f, the sliding resistance when the ball screw nut 17a rotates with respect to the bridge 6 can be kept small.

  (4) The piston 13 includes a sliding contact portion 13a that is in sliding contact with the bridge 6, and the ball bearings 15e and 15f are between the ball screw nut 17a and the bridge 6 and from the inner pad 1a rather than the sliding contact portion 13a. The piston 13 is disposed so as not to be contacted at a distant position. Therefore, most of the heat transmitted from the inner pad 1a to the piston 13 can be released from the sliding contact portion 13a in contact with the bridge 6 to the bridge 6 having a large heat capacity, and the heat is directly transferred from the piston 13 to the ball bearings 15e and 15f. Transmission can be avoided, and the heat resistance load of the ball bearings 15e and 15f can be reduced.

  (5) Since the bridge 6 includes the radiation fins 9 at positions upstream of the ball bearings 15e and 15f on the heat transfer path from the disk rotor 2 to the ball bearings 15e and 15f at the time of braking, the ball bearings 15e and 15f are provided. The heat load on the motor 3 and the ECU 10 can be kept small.

  (6) Since the radiating fins 9 are arranged along the flow of air generated during traveling, the heat radiation effect by the radiating fins 9 can be further enhanced.

First, the configuration will be described.
8 is a bottom view of the electric disc brake B of the second embodiment, FIG. 9 is a plan view of the electric disc brake B, FIG. 10 is a right side view of the electric disc brake B, and FIG. FIG. 12 is a front view of the electric disc brake B, and FIG. 13 is a rear view of the electric disc brake B. In addition, about the component same as Example 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The planetary gear 32 is a simple planetary gear composed of a sun gear 321, a carrier 322, and a ring gear 323. The sun gear 321 is connected to the output of the main shaft 31, and the carrier 322 is connected to the input of the input gear 33. Yes. The ring gear 323 is fixed to the torque member 5. The input gear 33 is rotatably supported via the torque member 5 and a ball bearing, and outputs the output of the planetary gear 32 to the linear drive converter 34.

  The linear drive converter 34 includes a piston (piston member) 35, a ball bearing (rotating sliding portion) 36, and a ball screw mechanism (piston motion conversion mechanism and bridge portion motion conversion mechanism) 17. The piston 35 and the ball screw mechanism 17 constitute a first motion converting means for converting the rotational motion of the rotating shaft of the electric motor 3 into a linear motion in the wheel axis direction and forcibly displacing the inner pad 1a with respect to the disc rotor 2. . Further, the ball bearing 36 and the ball screw mechanism 17 convert the rotational motion of the rotating shaft of the electric motor 3 into a linear motion in the wheel axis direction, and the bridge 6 is displaced in a direction in which the outer pad 1b is forcibly displaced with respect to the disc rotor 2. Second motion conversion means is configured.

  The piston part 35b is comprised from the ball screw screw part 35a and the piston part 35b. The ball screw screw portion 35a is spline-coupled to the input gear 33, and is connected to each other so as to be relatively movable in the axial direction and to be integrally rotatable. A disc spring 37 that is elastically deformable in the wheel axis direction is interposed between the ball screw nut 17 a and the bridge 6.

  The piston part 35b is provided integrally with the inner pad 1a, and is connected to the ball screw screw part 35a via a ball bearing 36. The two parts are connected to each other so that they can rotate relative to each other and cannot move relative to each other in the axial direction. . A seal 18 a is set between the piston portion 35 b and the bridge 6.

Next, the operation will be described.
[Brake force generation action]
The ECU 10 supplies a drive current to the motor stator 3b according to the brake operation amount of the driver. With this current supply, the motor stator 3b generates a rotational driving force with the motor rotor 3c, and rotates the main shaft 31 provided integrally with the motor rotor 3c.

  The rotation of the main shaft 31 is decelerated by the planetary gear 32 and then transmitted from the input gear 33 to the ball screw screw portion 35a, whereby the ball screw screw 35a rotates. Here, when the operating resistance (sliding resistance) of the ball screw screw 35a is smaller than the operating resistance of the ball screw nut 17a, the ball screw screw 35a rotates without changing its position in the wheel axis direction. Therefore, the rotation of the ball screw screw 35 a is converted into a linear motion of the piston portion 35 b by the ball screw mechanism 17, and the inner pad 1 a is pressed against the disc rotor 2.

  When the piston portion 35b receives a reaction force from the disk rotor 2 and the operation resistance of the ball screw screw 35a becomes larger than the operation resistance of the ball screw nut 17a, the ball screw screw 35a stops linear movement, but the ball screw screw 35a. Can rotate relative to the piston portion 35b by means of a ball bearing 36, so that it rotates by the driving force of the motor 3, and the ball screw nut 17a starts linear movement toward the motor 3 in the wheel axis direction. The linear motion of the ball screw nut 17 a is transmitted to the bridge 6 via the disc spring 37, and the outer pad 1 b provided integrally with the bridge 6 is pressed against the disc rotor 2.

  When the bridge 6 receives a reaction force from the disk rotor 2 and the operation resistance of the ball screw screw 35a becomes smaller than the operation resistance of the ball screw nut 17a, the inner pad 1a is again pressed against the disk rotor 2 by the linear movement of the piston portion 35b. It is done. That is, the above operation is repeated according to the motor driving force, and the frictional force is finally generated against the rotor friction surfaces 2a and 2b of the disk rotor 2 by the reaction force generated by the inner pad 1a and the outer pad 1b. A braking force is applied to the wheels.

Next, the effect will be described.
In the electric disc brake B of the second embodiment, in addition to the effects (1) and (2) of the first embodiment, the following effects can be obtained.
(7) Since the rotation sliding part is the ball bearing 36, the resistance when the ball screw screw part 35a rotates with respect to the ball screw screw part 35a can be kept small.

(Other examples)
The best mode for carrying out the present invention has been described based on the embodiments. However, the specific configuration of the present invention is not limited to the first and second embodiments, and departs from the gist of the invention. Even if there is a design change or the like within a range not to be included, it is included in the invention.

  For example, in the first and second embodiments, an example in which a planetary gear is provided as a speed reducer between the electric motor and the linear drive converter is shown. However, a configuration using a low rotation high torque electric motor and omitting the speed reducer It is also good.

  Moreover, in Example 1, although the example which provided two ball bearings between the ball screw nut and the bridge was shown, it is good also as a structure which can respond to a bigger thrust load by adding a thrust bearing and a needle bearing. .

  In the second embodiment, the piston is composed of two members, a ball screw screw part and a piston part, and an example in which a rotation sliding part that allows rotation of the ball screw screw part is provided between them is shown. It is good also as a structure which formed in this and provided the rotation sliding part between the piston and the inner pad.

  In the first and second embodiments, the operation at the time of braking is described on the assumption that the operating resistance of the first motion converting means is smaller than the operating resistance of the second motion converting means at the time of braking start. When the operation resistance of the second motion conversion means is smaller than the operation resistance of the first motion conversion means, when the bridge portion is first displaced by the second motion conversion means and the linear motion of the bridge portion is restricted, the first motion conversion means As a result, the piston member is displaced.

1 is a side view illustrating a configuration of an electric disc brake A according to a first embodiment. 1 is a plan view of an electric disc brake A. FIG. 1 is a right side view of an electric disc brake A. FIG. 1 is a left side view of an electric disc brake A. FIG. 1 is a front view of an electric disc brake A. FIG. 2 is a rear view of the electric disc brake A. FIG. It is a figure which shows the structure of the conventional electric disc brake. FIG. 6 is a bottom view of an electric disc brake B according to a second embodiment. 3 is a plan view of the electric disc brake B. FIG. 3 is a right side view of the electric disc brake B. FIG. 2 is a left side view of the electric disc brake B. FIG. 1 is a front view of an electric disc brake B. FIG. 2 is a rear view of the electric disc brake B. FIG.

Explanation of symbols

A Electric disc brake 1a Inner pad 1b Outer pad 2 Disc rotor 2a, 2b Rotor friction surface 3 Electric motor 3a Motor cover 3b Motor stator 3c Motor rotor 4 Linear drive converter 5 Torque member 5a Axle fitting bolt 6 Bridge 6a Cylinder surface 7 Harness 8 Axle 9 Radiation fin 10a ECU cover 10b ECU cover screw 10c ECU housing 11 Resolver 11a Resolver stator 11b Resolver rotor 12 Planetary gear 121 Ring gear 122 Pinion 122a First gear stage 122b Second gear stage 13 Piston 13a Sliding contact part 13a Piston 13a Sliding Contact 14 Main shaft 14a Grooves 15a, 15b, 15c, 15d, 15e, 15f Ball bearing 16 Input gear 17 Ball screw mechanism 17a Ball screw nut 17a Cut 17b Ball 17c Ball screw screw 18a, 18b Seal 19 Stopper 20 Latch mechanism 21 Pad slide guide 31 Main shaft 32 Planetary gear 33 Input gear 34 Linear drive converter 35 Piston 35a Ball screw screw part 35b Piston part

Claims (6)

In the electric disc brake that presses the inner pad and the outer pad that are arranged opposite to each other by the driving force of the electric motor against the disc rotor to brake the wheel,
The electric motor is fixed to the vehicle body side member in a position invariant in the wheel axis direction,
A first motion converting means for converting the rotational motion of the rotating shaft of the electric motor into a linear motion in a wheel axis direction, and forcibly displacing the inner pad with respect to the disk rotor;
A bridge portion that is displaceable relative to the vehicle body side member in a wheel axis direction, and that displaces the outer pad relative to the disk rotor;
A second motion converting means for converting the rotational motion of the rotating shaft of the electric motor into a linear motion in a wheel axis direction, and displacing the bridge portion in a direction in which the outer pad is forcibly displaced with respect to the disk rotor;
An electric disc brake comprising: In the electric disc brake according to claim 1,
The first motion conversion means is a piston member that rotates integrally with the rotating shaft of the electric motor and is relatively movable in the axial direction with respect to the motor rotating shaft, and the rotational motion of the piston member linearly with the rotation of the piston member. A piston motion conversion mechanism that converts motion,
The second motion converting means includes a rotary sliding portion that allows a rotational motion of the piston member and a linear motion of the piston member when the linear motion of the piston member is restricted even when the linear motion of the piston member is restricted. An electric disc brake comprising: a bridge portion motion conversion mechanism that converts a rotational motion of a rotating shaft of a motor into a linear motion of the bridge portion in a wheel axis direction. In the electric disc brake according to claim 2,
An electric disc brake characterized in that the rotary sliding portion is a bearing member. In the electric disc brake according to claim 3,
The piston member includes a sliding contact portion that is in sliding contact with the bridge portion,
The bearing member is disposed between the bridge portion motion conversion mechanism and the bridge portion, and is disposed so as not to contact the piston member at a position farther from the inner pad than the sliding contact portion. Electric disc brake characterized by In the electric disc brake according to claim 4,
The electric disk brake according to claim 1, wherein the bridge portion includes a radiating fin at a position upstream of the bearing member on a heat transfer path from the disk rotor to the bearing member during braking. In the electric disc brake according to claim 5,
An electric disc brake, wherein the heat dissipating fins are arranged along a flow of air generated during traveling.

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