JP4711704B2 - Electric brake device - Google Patents

Description

  The present invention relates to an electric brake device that generates a braking force by pressing a friction member that moves forward and backward by an electric motor against a rotating member that rotates together with a wheel.

The pedal force applied by the driver to the brake pedal is converted into an electrical signal by the pedal force sensor, and the rotation of an electric actuator such as a motor driven by this electrical signal is converted into thrust by the ball screw mechanism and connected to the ball screw mechanism. A so-called BBW (brake-by-wire) type brake device that brakes a wheel by pressing a pad against a disk rotor is known from Japanese Patent Application Laid-Open No. 2004-122867.
JP 2000-18293 A

  By the way, the disc brake device pad is pressed against the disc rotor with the thrust generated by the electric actuator to generate a braking force, and then when the thrust of the electric actuator is released, the pad is pushed back by the reaction force received from the disc rotor. Is driven in the reverse direction to generate regenerative power. However, the above-mentioned conventional ones are wasted without using this regenerative power effectively.

  The present invention has been made in view of the above circumstances, and an object thereof is to effectively use regenerative power generated by an electric motor of an electric brake device.

In order to achieve the above object, according to the first aspect of the present invention, in an electric brake device that generates a braking force by pressing a friction member that moves forward and backward with an electric motor against a rotating member that rotates together with the wheel, the electric motor A main power source for driving the motor, a capacitor as an auxiliary power source, and a switch for switching the connection state between the electric motor and the main power source and the capacitor. The switch uses electric power from the main power source when the brake is operated. a first control mode for driving the power from the capacitor as a non-connected state and a second control mode, the main power source and the electric motor during braking to charge the capacitor with the regenerative electric power of the electric dynamic motor when the brake is released electric braking apparatus is proposed to the third control mode and wherein the available der Rukoto switched to drive the electric motor with a low voltage only.

According to the second aspect of the present invention, in addition to the configuration of the first aspect, the switch connects the main power source and the capacitor in series with the electric motor when the brake is operated , so that the electric motor can be operated at a high voltage. An electric brake device characterized in that it can be switched to a fourth control mode for driving is proposed.
Is proposed.

Furthermore, according to the invention described in claim 3, in addition to the configuration of claim 1 or 2, the switch disconnects the main power source from the electric motor in the second control mode. An electric brake device is proposed.

The brake pads 14a embodiment, 14b corresponds to the friction member of the present invention, the brake disk 13 of the example you corresponds to the rotating member of the present invention.

According to the first aspect, the friction member to move forward by an electric motor electric braking apparatus which generates a braking force in pressure contact with the rotary member which rotates together with the wheel, in the first control mode, mainly during braking power In the second control mode , the electric motor is reversely rotated by the reaction force received by the friction member from the rotating member when the brake is released, and the regenerative electric power generated by the electric motor is used as an auxiliary power source . In the third control mode, the main power source and the electric motor are disconnected from each other and the electric motor is driven at a low voltage only by the electric power from the capacitor in the third control mode. Therefore, the regenerative power is effectively used. As a result, the power consumption of the electric brake device can be reduced.

According to the configuration of claim 2, in the fourth control mode, the main power source and the capacitor can be connected in series to the electric motor when the brake is operated, and the electric motor can be driven at a high voltage. Can be boosted with the voltage of the capacitor to improve the starting performance of the electric motor.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 6 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of an electric brake having a function of an electric stop brake, FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1 is a sectional view taken along line 3-3 in FIG. 1, FIG. 4 is an explanatory diagram of the operation when the electric stop brake is operated, FIG. 5 is an explanatory diagram of an operation when the electric stop brake is forcibly released, and FIG. 6 is a drive circuit diagram of the electric motor. It is.

  As shown in FIGS. 1 to 3, the electric brake that can also be used as an electric stop brake includes a brake caliper 11 that is supported by a knuckle or the like so as to be movable in the left-right direction in FIG. 1. Brake pads 14a and 14b are provided on opposite surfaces of a pair of back plates 12a and 12b that are supported by guide means (not shown) so as to be able to approach and separate from each other. It is done. A brake piston 15 is supported on the main body 11a of the brake caliper 11 so as to be able to advance and retreat. The brake caliper 11 is pressed against the back surface of one back plate 12a by the brake piston 15 so that the brake caliper 11 is moved to the right in FIG. The arm portion 11c connected to the main body portion 11a of the brake caliper 11 via the bridging portion 11b presses the back surface of the other back plate 12b, so that both brake pads 14a and 14b A braking force is generated in contact with both side surfaces. A dustproof boot 16 is mounted between the brake piston 15 and the brake caliper 11.

  The electric motor M housed in the main body 11a of the brake caliper 11 includes a plurality of stator coils 17 fixed to the inner surface of the main body 11a, and a ball bearing 18 that is rotatable around the axis L inside the stator coils 17. And a plurality of permanent magnets 20 fixed to the outer peripheral surface of the motor output shaft 19 so as to face the inner peripheral surface of the stator coils 17. A cylindrical female screw member 21 is supported inside the motor output shaft 19 by a pair of ball bearings 22 and 23 so as to be relatively rotatable. Between the male screw member 24 extending integrally on the axis L from the back surface of the brake piston 15. Are arranged with a plurality of balls 25. These female screw member 21, male screw member 24 and balls 25 ... constitute a ball screw mechanism S.

  A planetary gear mechanism P is arranged inside the main body 11 a of the brake caliper 11 so as to connect the electric motor M and the ball screw mechanism S. The planetary gear mechanism P disposed on the axis L includes a sun gear 31 fixed to the motor output shaft 19, a planetary carrier 32 serving also as a ratchet wheel fixed to the female screw member 21 of the ball screw mechanism S, and an outer periphery of the planetary carrier 32. And a plurality of pinions 35 that are supported on the planetary carrier 32 via pinion shafts 34 and mesh with the sun gear 31 and the ring gear 33 at the same time. Between the planetary carrier 32 and the inner surface of the main body 11a, a thrust bearing 36 for supporting a braking reaction force that the brake piston 15 receives from the brake disk 13 is disposed.

  The planetary gear mechanism P includes three elements: a sun gear 31, a planetary carrier 32 (ratchet wheel), and a ring gear 33. The sun gear 31 constituting the input element is fixed to the motor output shaft 19 and the planetary constituting the output element. The carrier 32 is fixed to the female screw member 21 of the ball screw mechanism S via the connecting shaft 37, and the ring gear 33 constituting the fixing element is fixed to the main body portion 11 a of the brake caliper 11. At this time, the sun gear 31 is supported on the outer periphery of the connecting shaft 37 disposed on the axis L so as to be relatively rotatable.

  The electric brake includes a ratchet mechanism R for causing it to function as an electric stop brake. The ratchet mechanism R has a ratchet pawl 42a at one end thereof, which is pivotally supported by the planetary carrier 32 (ratchet wheel) and a central portion by a fulcrum pin 41 so that the ratchet mechanism R can engage with the ratchet teeth 32a of the planetary carrier 32. The ratchet pawl 42, the torsion coil spring 43 that urges the ratchet pole 42 in the direction in which the ratchet pawl 42a is detached from the ratchet teeth 32a, and the one end side of the ratchet pawl 42 are pressed so that the ratchet pawl 42a is moved to the ratchet teeth 32a. .. Are provided, and a bolt 45 capable of pressing the other end of the ratchet pole 42 is provided.

  As shown in FIG. 6, the minus terminal of the main power source E that drives the electric motor M is connected to the grounding part G via the line a, and the plus terminal is connected to one terminal of the electric motor M via the line b. The other terminal of the electric motor M is connected to the grounding part G through the line c. In the line b, a first switch S1 for driving / stopping the electric motor M with electric power from the main power source E is arranged.

  A second switch S2, a capacitor C as an auxiliary power source, and a fourth switch S4 are arranged in series on a line d between the line b on the electric motor M side of the first switch S1 and the ground portion G. . A third switch S3 is arranged on a line e connecting the line b between the main power source and the first switch S1 and the line d between the capacitor C and the fourth switch S4.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When the electric brake is used as a service brake, when the electric motor M is driven forward in accordance with the driver's brake operation, the rotation of the rotor output shaft 19 is input to the sun gear 31 of the planetary gear mechanism P, and the ring gear 33 is fixed so as not to rotate. Therefore, the rotation of the sun gear 31 is transmitted to the female screw member 21 of the ball screw mechanism S via the pinions 35..., The planetary carrier 32 and the connecting shaft 37. When the female screw member 21 rotates, the male screw member 21 engaged therewith via the balls 25... Moves forward together with the brake piston 15, and the brake piston 15 abuts the brake pads 14 a and 14 b against the brake disk 13 to generate a braking force. To do. When the electric motor M is driven in reverse, the brake piston 15 moves backward, the brake pads 14a and 14b are separated from the brake disc 13, and the braking force is released.

  When the electric brake is used as an electric stop brake, when the driver turns on the parking switch, the electric motor M rotates forward and the brake piston 15 moves forward, so that the braking force is applied in the same manner as in the case of the service brake described above. appear. When a predetermined braking force is generated, the solenoid 44 is energized, and the ratchet pole 42 pressed by the solenoid 44 is counteracted around the fulcrum pin 41 against the elastic force of the torsion coil spring 43 as shown in FIG. By swinging clockwise, the ratchet pawl 42a of the ratchet pole 42 is engaged with the ratchet teeth 32a of the planetary carrier 32.

  When energization of the electric motor M is stopped in this state, the brake pads 14a and 14b are retracted by the reaction force received from the brake disc 13, and the planetary carrier 32 is about to rotate in the braking release direction. The pawl 42a meshes strongly with the ratchet teeth 32a of the planetary carrier 32, and the electric stopping brake is kept in the operating state even when the energization of the solenoid 44 is released.

  When the driver turns off the parking switch, the electric motor M is driven in the forward rotation direction for a moment, and the planetary carrier 32 rotates slightly in the braking direction. As a result, the ratchet pawl 42a of the ratchet pole 42 is disengaged from the ratchet teeth 32a of the planetary carrier 32, and the ratchet pole 42 rotates clockwise to the position of FIG. Thus, the restraint of the planetary carrier 32 is released. Then, the brake pads 14a and 14b are automatically retracted by the reaction force received from the brake disc 13, and the operation of the electric stop brake is released. At this time, the electric motor M may be reversed to assist the reaction force received by the brake pads 14a, 14b from the brake disc 13.

  Now, if the electric motor M fails during the operation of the electric stop brake, the ratchet mechanism R cannot be disengaged, the electric stop brake remains operated, and the vehicle cannot run. In such a case, as shown in FIG. 5, by manually rotating the bolt 45, the ratchet pole 42 is pressed and swung clockwise around the fulcrum pin 41, and the ratchet pawl 42a of the ratchet pole 42 is moved to the planetary position. It can be forcibly separated from the ratchet teeth 32a of the carrier 32. As a result, it is possible to avoid a situation in which the operation of the electric stop brake cannot be released when the electric motor M including the failure of the power source cannot be operated.

  Next, drive control and regenerative control of the electric motor M will be described with reference to FIG.

In the normal first control mode in which the electric brake is operated, when only the first switch S1 is turned on, the electric motor M is driven forward by the electric power supplied from the main power source E.

In the second control mode at the time of regeneration to release the electric braking apparatus, is turned on only the second switch S2 and the fourth switch S4, the brake pads 14a, 14b are electric motor M is driven in reverse by the reaction force received from the brake disk 13 Thus, it functions as a generator, and the capacitor C is charged with the generated regenerative power.

In the third control mode in which the electric motor M is driven at a low voltage while the capacitor C is charged in this way, when only the second switch S2 and the fourth switch S4 are turned on, the electric power that the capacitor C discharges is used. The electric motor M is driven to rotate forward, and the electric brake generates a braking force smaller than normal.

Further , in the fourth control mode at the time of boosting in which the electric motor is driven at a high voltage with the capacitor C charged, when only the second switch S2 and the third switch S3 are turned on, the voltage of the main power supply E and the capacitor C The electric motor M is normally driven at a voltage obtained by adding these voltages, and the response of the electric brake is improved compared to the normal time.

As described above, the regenerative electric power generated by the electric motor M when releasing the electric brake is charged in the capacitor C and reused in various modes, so that the power consumption of the electric brake can be reduced or the magnitude of the braking force can be reduced. Can be adjusted.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, although the electric brake of the embodiment also uses the service brake as a parking brake, the present invention can also be applied to a dedicated service brake.

Cross section of electric brake with electric stop brake function 2-2 sectional view of FIG. 3-3 sectional view of FIG. Action explanatory diagram at the time of operation of electric stop brake Action explanatory diagram at the time of forced release of electric stop brake Electric motor drive circuit diagram

C capacitor (auxiliary power supply)
E Main power supply M Electric motor
S1, S2, S3, S4 switch 13 Brake disc (rotary member)
14a Brake pad (friction member)
14b Brake pad (friction member)

Claims (3)

In the electric brake device that generates a braking force by pressing the friction member (14a, 14b) that moves forward and backward by the electric motor (M) against the rotating member (13) that rotates together with the wheel,
A main power source (E) for driving the electric motor (M), a capacitor (C) as an auxiliary power source, and a switch for switching the connection state of the electric motor (M), the main power source (E) and the capacitor (C) ( S1, S2, S3, S4)
Said switch (S1, S2, S3, S4 ) , the first control mode and, in the electrostatic movement motor when the brake is released to drive the electric motor (M) at a power from the main power supply during brake actuation (E) (M ) and a second control mode for charging the capacitor (C) in the regenerative power of the electric motor only the power from the capacitor (C) as a non-connected state the main power supply and (E) an electric motor (M) during braking electric brake apparatus according to claim available der Rukoto switching between third control mode for driving the (M) at a low voltage. The switches (S1, S2, S3, S4) connect the main power source (E) and the capacitor (C) in series to the electric motor (M) when the brake is operated , and drive the electric motor (M) with a high voltage. The electric brake device according to claim 1, wherein the electric brake device can be switched to a fourth control mode . The switch (S1, S2, S3, S4) disconnects the main power supply (E) from the electric motor (M) in the second control mode. Electric brake device.

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