JP4065994B2 - Electric disc brake device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric disc brake device capable of reducing the number of cables for driving an actuator so as to achieve a parking function. <P>SOLUTION: A neutral point 46 in a motor coil 46 in a caliper is connected through a power cable 60 to a lock mechanism coil 50, so that the lock mechanism coil 50 is driven by voltage from the neutral point 46. The power cable 60 is included in the caliper, and not extended from the caliper (toward a controller 40). The controller 40 is connected toward the lock mechanism coil 50 by a single control cable 54 to reduce the number of cables for achieving the function of the parking brake. Constitution of the whole device can thus be simplified. As the number of the cables is reduced, material cost is reduced, assembling manhours is reduced, and bending performance of the cables is improved. <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric disc brake device that generates a braking force by a rotational force of an electric motor.
[0002]
[Prior art]
As an electric disc brake device used for a vehicle such as an automobile, there is one configured by adding a parking brake function. As an example thereof, a motor that advances a pair of brake pads opposed to each other across the disk rotor toward the disk rotor, a holding mechanism that holds thrust against the brake pad by the motor, an actuator that drives the holding mechanism, There is an electric disc brake device having a caliper that encloses (see Patent Document 1). In this electric disc brake device, the holding mechanism and the actuator cooperate with each other by energizing and shutting off the actuator, thereby exhibiting a parking brake function. Further, as a motor for an electric disc brake device, there is a motor using a star-connected three-phase motor (see Patent Document 2).
[0003]
[Patent Document 1]
JP 2001-232640 A [Patent Document 2]
Japanese Patent Laid-Open No. 2002-058288
[Problems to be solved by the invention]
By the way, in the electric disk brake device according to the related art described above, an actuator that drives the holding mechanism is required in order to exhibit the parking brake function. Accordingly, a power cable (solenoid wire) for supplying power to the actuator and a cable (control cable) for controlling the actuator are connected to the actuator side, and the power cable and the control cable are outside the caliper (inside the car). It was necessary to connect to a controller including a motor driver (motor power supply unit) provided.
[0005]
For this reason, a power cable is provided in addition to the power line required to supply power to the motor to connect the controller and the members in the caliper in connection with the provision of the solenoid for demonstrating the parking brake function. As a result, the number of control cables has increased, and in reality, improvement has been demanded from the viewpoint of preventing the apparatus from becoming complicated. Further, the power cable and the control cable are provided so as to extend from the caliper to the outside of the caliper, and have become long. For this reason, in order to ensure a required current, it is necessary to increase the diameter of the cable, and further, the flexibility is lowered, the routing property is lowered, and the workability is lowered.
[0006]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric disk brake device capable of exhibiting a parking function by reducing the number of cables for driving an actuator.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention, a pair of brake pads facing each other with the disc rotor interposed therebetween are advanced toward the disc rotor, and a multi-phase motor having a neutral point is retained, and the thrust of the motor against the brake pad is maintained. wherein the holding mechanism, the electric disc brake apparatus having a caliper enclosing an actuator for driving the holding mechanism, wherein the actuator has one end portion side is grounded, the other end portion is connected to the neutral point And
[0008]
According to a second aspect of the present invention, in the electric disc brake device according to the first aspect, a switching element is provided in a circuit including the neutral point and the actuator so that the actuator can be energized and cut off. And
[0009]
DETAILED DESCRIPTION OF THE INVENTION
An electric disc brake device according to a first embodiment of the present invention will be described with reference to FIGS. In FIG. 1 to FIG. 3, the electric disc brake device 1 includes a caliper 4 in the axial direction of the disc rotor 2 on a carrier 3 fixed to a non-rotating portion (such as a knuckle) of the vehicle located inside the vehicle from the disc rotor 2. Supports floating. A pair of brake pads 5 and 6 are arranged to face each other with the disc rotor 2 interposed therebetween. The brake pads 5 and 6 are supported by the carrier 3 so as to be movable in the axial direction of the disc rotor 2.
[0010]
The caliper 4 includes a claw member 9 having a claw portion 7 on the distal end side and an annular base 8 on the proximal end side, and a caliper body 10 coupled to the claw member 9. The brake pads 6 are arranged to face each other. The caliper body 10 includes an annular body 11 coupled to the annular base 8 of the claw member 9 and a motor case 12 coupled to the annular body 11. The motor case 12 includes a cylindrical motor case main body 13 connected to the annular body 11, a motor end plate 14 covering the opening of the motor case main body 13, and a hole 15 formed in the side wall of the motor case main body 13. And a housing 16 provided on the housing.
[0011]
In the caliper 4, a split type piston 20 that presses the brake pad 5 on the inner side of the vehicle against the disc rotor 2, a motor 21, and a ball ramp mechanism that converts the rotation of the motor 21 into a linear motion and transmits it to the piston 20. 22, a differential reduction mechanism 23 that decelerates the rotation of the motor 21 and transmits it to the ball ramp mechanism 22, and pad wear that compensates for pad wear by changing the position of the piston 20 in accordance with wear of the brake pads 5 and 6. A compensation mechanism 24 and a parking brake lock mechanism (holding mechanism) 25 that establishes a parking brake (parking brake) are provided.
[0012]
The ball ramp mechanism 22 includes a ring-shaped first disk (rotating member) 27 that is rotatably supported via a bearing 26 on the inner peripheral portion of the coupling portion of the annular base body 8 and the annular body 11 of the caliper body 10. A ring-shaped second disk 29 having a space and coupled to the piston cylinder 28 of the piston 20 inserted into the space, and a ball 30 interposed between the disks 27 and 29. I have. The second disk 29 is held so that its rotation is restricted, and the rotational force received from the first disk 27 via the ball 30 is converted into a linear motion and transmitted to the piston 20.
[0013]
The piston 20 is divided into the piston cylinder part 28 and a piston main body 31 having a diameter larger than that of the piston cylinder part 28. The piston main body 31 is composed of a piston cylinder part 28 and a ball. A force from the ramp mechanism 22 (motor 21) is received. The piston cylinder part 28 is supported by a supporting cylinder described later via a piston 20 engaging member so as not to rotate. A reaction force sensor 33 is disposed between the bottom portion 32 of the hollow portion formed on the piston body 31 side of the piston cylinder body 28 and the piston body 31, and detects the reaction force from the piston body 31. Yes. The signal line 34 of the reaction force sensor 33 passes through a pipe 36 inserted through the support cylinder 35 and is connected to a controller 40 provided on the vehicle body. The support cylinder 35 is supported on the motor case 12 via a cylinder support member 41.
[0014]
The motor 21 includes a stator 43 fitted and fixed to the motor case 12 and a hollow rotor 44 disposed in the stator 43, and the rotor 44 is rotatably supported by the motor case 12. The motor 21 operates to rotate the rotor 44 by a desired angle with a desired torque in response to a command from the controller 40. The rotation angle of the rotor 44 is determined by a position detector 42 (resolver or the like) disposed in the rotor 44. ). In the present embodiment, the motor 21 rotates the rotor 44 in the clockwise direction in FIG. 2 in response to a braking force generation command from the controller 40.
[0015]
The stator 43 of the motor 21 is provided with a star-connected U-phase coil 45U, V-phase coil 45V, and W-phase coil 45W (three-phase winding, hereinafter referred to as the motor coil 45 as appropriate). Ends 47U, 47V, 47W opposite to the neutral point 46 of the motor coil 45 are connected to a battery 49 via a motor driver 48 that converts direct current into three-phase alternating current. One end portion 50 a of the neutral point 46 is connected to the other end portion 50 b of a lock mechanism coil (actuator) 50, which will be described later, grounded to a ground portion 51 provided in the caliper 4 via a power cable 60. A circuit (lock mechanism coil circuit) 52 is formed so that the voltage at the neutral point 46 is applied to the lock mechanism coil 50.
[0016]
A switching transistor (switching element) 53 is interposed between the lock mechanism coil 50 and the ground portion 51 in the lock mechanism coil circuit 52. The base of the switching transistor 53 is connected to the controller 40 via the control cable 54. Upon receiving a control signal from the controller 40, the switching transistor 53 is turned on and off to open and close the lock mechanism coil circuit 52, energize and shut off the lock mechanism coil 50, and hence the plunger 55 of the parking brake lock mechanism 25. It is possible to control the advance and retreat of the. The control cable 54 extends from the inside of the lock mechanism coil 50 (parking brake lock mechanism 25) and the caliper 4 to the controller 40 and thus to the outside of the caliper 4.
[0017]
The motor driver 48 generates voltages (U-phase voltage, V-phase voltage, and W-phase voltage) that are different in phase by 120 ° according to a control signal from the controller 40, and uses the voltages as a U-phase coil 45U and a V-phase coil 45V. And W-phase coil 45W (motor coil 45). As shown in FIG. 5, the motor driver 48 has six transistors (first to sixth transistors) 61 to 66 which are turned on and off by a control signal from the controller 40, and these are configured as a three-phase bridge circuit. It has become.
[0018]
The emitter (reference numeral omitted) of the first transistor 61 and the collector (reference numeral omitted) of the second transistor 62 are connected, and the connecting portion is connected to the U-phase coil 45U, and the first and second transistors 61 and 62 A U-phase series element body 67U is configured. Similarly, the third and fourth transistors 63 and 64 constitute a V-phase series element body 67V, and the fifth and sixth transistors 65 and 66 constitute a W-phase series element body 67W. A cable connecting the motor driver 48 to the U-phase coil 45U, the V-phase coil 45V, and the W-phase coil 45W is hereinafter referred to as a power line 68. The power line 68 extends from the caliper 4 to the motor driver 48 (controller 40) and thus to the outside of the caliper 4.
[0019]
The collectors of the first, third, and fifth transistors 61, 63, and 65 are connected to the positive terminal of the battery 49, and the emitters of the second, fourth, and sixth transistors 62, 64, and 66 are the negative terminals of the battery 49. It is connected to the. The motor driver 48 inputs a control signal and controls the voltage applied to the motor coil 45 (U-phase coil 45U, V-phase coil 45V, and W-phase coil 45W). The output voltage to the U-phase coil 45U is adjusted by changing the ratio [duty ratio] of the on-time of the first and second transistors 61 and 62. The longer the on-time of the first transistor 61, the higher the output voltage to the U-phase coil 45U. Third and fourth transistors 63 and 64 (V-phase series element body 67V) connected to the V-phase coil 45V and fifth and sixth transistors 65 and 66 (W-phase series element body 67W) connected to the W-phase coil 45W. ) Is the same as the first and second transistors 61 and 62 (U-phase series element body 67U) described above.
[0020]
As described above, the motor driver 48 applies a voltage to the U-phase coil 45U, the V-phase coil 45V, and the W-phase coil 45W. As shown in FIG. A sinusoidal voltage that is 120 ° out of phase is applied. At this time, if the DC voltage input to the motor driver 48 is V, the voltage at the neutral point 46 of the motor coil 45 is V / 2. When the duty ratio is 50%, the output voltage of the motor driver 48 is V / 2 for all of the U phase, V phase, and W phase. At this time, there is no potential difference between the U phase, V phase, and W phase. No current flows. If the sine wave can be adjusted to change the voltage amplitude of the U-phase, V-phase, and W-phase around the duty ratio of 50%, and the sine wave is 120 ° out of phase as described above, the neutral point The voltage is V / 2, which is the center of the voltage amplitude.
[0021]
As shown in FIGS. 2 and 3, the parking brake locking mechanism 25 includes a ratchet wheel 71 provided with a ratchet 70 on the outer peripheral portion and connected to the rotor 44, and a plunger 55 that moves forward and backward with respect to the ratchet 70 of the ratchet wheel 71. A ratchet solenoid mechanism 72. The plunger 55 is arranged so that the axial direction is directed to the center of the pawl wheel 71, and the engaging claw 73 provided at the tip can be brought into contact with the ratchet 70.
[0022]
The ratchet solenoid mechanism 72 includes a solenoid mechanism main body 74 that supports the plunger 55 so as to be movable back and forth, the lock mechanism coil 50 that is supported by the solenoid mechanism main body 74 and generates an electromagnetic force with respect to the plunger 55, and a tension spring 75. I have. The solenoid mechanism main body 74 is disposed outside the motor case main body 13 so that the plunger 55 protrudes from the hole 15 of the motor case main body 13 toward the claw wheel 71 and is covered with the housing 16.
[0023]
The tension spring 75 is provided between the plunger 55 and a predetermined fixing portion 76 (the position of the fixing portion 76 is shown for convenience in FIG. 2), and the plunger 55 is placed at the center of the pawl wheel 71. I try to pull it. When the coil of the solenoid mechanism main body 74 is not energized (a state where no braking force is generated), the engaging claw 73 of the plunger 55 is engaged with the ratchet 70.
[0024]
In the electric disc brake device 1 configured as described above, the braking force is converted into a linear motion via the ball ramp mechanism 22 with respect to the rotational force of the motor 21 generated by energization of the motor 21 to advance the piston 20. To generate. That is, as the piston 20 advances, the brake pads 5 and 6 on the inner side of the vehicle press the disc rotor 2, and the caliper 4 is displaced by this reaction force and the claw portion 7 presses the brake pads 5 and 6 against the disc rotor 2. The brake pads 5 and 6 sandwich the disc rotor 2 to generate a braking force.
[0025]
When functioning as a parking brake, the switching transistor 53 is turned on (the lock mechanism coil circuit 52 is closed) to energize the lock mechanism coil 50, and the plunger 55 resists the spring force of the tension spring 75. The engaging claw 73 is disengaged from the ratchet 70 and, as described above, the motor coil 45 is energized to generate the piston 20 thrust, and thereafter, the lock mechanism coil 50 and the motor coil Shut off the power to 45.
[0026]
When the energization of the lock mechanism coil 50 is interrupted, the engagement claw 73 is brought into contact with the ratchet 70 by the spring force of the tension spring 75 in the downward direction in FIG. On the other hand, when the motor coil 45 is de-energized, the rotor 44 of the motor 21 (and thus the pawl wheel 71) returns in the returning direction (counterclockwise in FIG. 2) due to the reaction force of the pressing force of the brake pads 5 and 6. Receives rotational force. At this time, since the engaging claw 73 is in contact with the ratchet 70 as described above, the pawl wheel 71 and the rotor 44 are locked by the engaging claw 73 (plunger 55), and the thrust of the piston 20 is maintained. The function as a parking brake is exhibited.
[0027]
Further, as described above, the switching transistor 53 is closed and operated while the parking brake is applied without energizing the lock mechanism coil 50 and the motor coil 45. Then, the lock mechanism coil 50 is energized to generate an electromagnetic force, and an upward force is applied to the plunger 55. For this reason, the plunger 55 is lifted against the spring force of the tension spring 75, and the engagement of the engagement pawl 73 with the ratchet 70 is released, the pawl wheel 71 and the rotor 44 become free, and the parking brake is released. Canceled.
[0028]
When the switching transistor 53 is turned off (the lock mechanism coil circuit 52 is opened) and the energization of the lock mechanism coil 50 is stopped, the force that the lock mechanism coil 50 pulls up the plunger 55 disappears, and the tension spring 75 The engaging claw 73 is engaged with the ratchet 70 by the spring force, the rotor 44 is locked, the piston 20 thrust is maintained, and the parking brake is activated.
[0029]
In the present embodiment, the parking brake lock mechanism 25 having the lock mechanism coil 50 (actuator, solenoid) is provided as described above, and the parking brake is actuated and released by energizing and shutting off the lock mechanism coil 50. be able to. As described above, the power supply cable to the lock mechanism coil 50 is included in the caliper 4 using the power cable 60 that connects the neutral point 46 of the motor coil 45 and the lock mechanism coil 50. It is not pulled out of the caliper 4 such as the controller 40. Therefore, the above-described function of the parking brake can be achieved with one cable for connecting the lock mechanism coil 50 (solenoid) and the controller 40 as one control cable 54 with the number of cables reduced. For this reason, the structure of the whole apparatus can be simplified. Further, with the reduction in the number of cables as described above, it is possible to reduce the material cost, reduce the number of assembly steps, and improve the flexibility of the cable.
[0030]
Furthermore, since the power supply to the lock mechanism coil 50 is performed by one power cable 60 connected to the neutral point 46 of the motor coil 45 in the caliper 4, the length can be shortened. For this reason, the power loss is reduced, the supply current for operating the lock mechanism coil 50 can be suppressed, and accordingly, the diameter of the cable for supplying power to the solenoid (lock mechanism coil 50) can be reduced. It is possible to improve the bendability of the cable and to ensure good routing performance.
[0031]
Further, in the above-described conventional technology, two cables, for example, a plus side and a minus side are necessary to connect a solenoid in the caliper (corresponding to the lock mechanism coil 50) and a controller (power supply) outside the caliper. It is said. On the other hand, according to the present embodiment, the power supply to the lock mechanism coil 50 can be performed by the single power cable 60 and the power cable 60 is arranged in the caliper 4 in a short state. For this reason, according to the present embodiment, compared with the above-described prior art, the overall configuration of the apparatus can be simplified and the diameter of the cable for supplying power to the lock mechanism coil 50 can be significantly reduced. It is possible to further improve the property and the routing property.
[0032]
Moreover, since the one end part 50a of the locking mechanism coil 50 is connected to the grounding part 51 in the caliper 4, the length of the power cable connecting the one end part 50a of the locking mechanism coil 50 and the grounding part 51 in the caliper 4 is also increased. It's short. For this reason, it is possible to further reduce the diameter of the power cable, thereby improving the flexibility and ensuring good routing performance.
[0033]
Next, a second embodiment of the present invention will be described with reference to FIG.
The second embodiment is different from the first embodiment in that a Zener diode 76 is provided in the lock mechanism coil circuit 52 in place of the switching transistor 53 of the first embodiment. When the voltage of the zener diode 76 is V / 2, no current flows through the lock mechanism coil 50 because there is no potential difference between both ends of the lock mechanism coil 50.
[0034]
On the other hand, as shown in FIG. 8, the centers of the voltage amplitudes of the U-phase coil 45U, the V-phase coil 45V, and the W-phase coil 45W are shifted to, for example, 3V / 4 (shifted by changing the duty ratio). The voltage at the neutral point 46 of the motor coil 45 can be changed to 3V / 4, and the lock mechanism coil 50 can be energized. If a coil that can be operated at a voltage of V / 4 is used as the lock mechanism coil 50, the parking brake lock mechanism 25 and thus the plunger 55 can be operated. For this reason, in the second embodiment, the lock mechanism coil 50 uses a coil that can operate at a voltage of V / 4, and the parking brake lock mechanism 25 exhibits a parking brake function.
[0035]
The above-described shift of the center of the voltage amplitude is achieved as follows. That is, the voltage amplitude of the U-phase coil 45U, the V-phase coil 45V, and the W-phase coil 45W is determined by the duty for driving the upper and lower switching elements (for example, the first and second transistors 61 and 62 in FIG. 5). If the duty ratio of the upper and lower switching elements is 50%, V / 2 is assumed, and the duty ratio of the upper switching element is 75% and the duty ratio of the lower switching element is 25%. The center voltage of the amplitude is 3V / 4.
[0036]
In the second embodiment, the lock mechanism coil circuit 52 is opened / closed in accordance with the voltage applied to the Zener diode 76 to energize and shut off the lock mechanism coil 50. Therefore, since the parking brake lock mechanism 25 can be locked and released by the voltage of the neutral point 46 of the motor coil 45 and the voltage of the power line 68, the controller 40 and the caliper 4 used in the first embodiment The control cable 54 for connecting is eliminated. For this reason, in 2nd Embodiment, the structure of the whole apparatus can be simplified more compared with 1st Embodiment.
[0037]
In each of the above embodiments, the motor 21 has a three-phase star connection as an example. However, the present invention is not limited to this, and other types such as a four-phase connection, a six-phase star connection, and a staggered connection having a neutral point are used. You may use this invention for a motor. Further, as the actuator, an electromagnetic clutch that separates the motor power may be used instead of the lock mechanism coil 50.
[0038]
【The invention's effect】
According to the first aspect of the present invention, since the electric power can be supplied to the actuator by connecting the neutral point of the motor and the actuator, the number of cables required to drive the actuator can be reduced.
According to the second aspect of the present invention, a zener diode can be used as the switching element, and the on / off operation of the actuator and the drive control of the holding mechanism can be performed according to the voltage applied to the zener diode. The control cable for controlling can be abolished.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a circuit for a lock mechanism coil of the electric disk brake device shown in FIG. 3 according to a first embodiment of the present invention.
FIG. 2 is a diagram schematically showing the parking brake lock mechanism of FIG. 3;
FIG. 3 is a cross-sectional view schematically showing the electric disk brake device according to the first embodiment of the present invention.
4 is a circuit diagram showing a wiring state of a caliper and a controller of the electric disk brake device of FIG. 3. FIG.
FIG. 5 is a view showing a motor driver used in the electric disk brake device of FIG. 3;
6 is a waveform diagram showing an output voltage of the motor driver of FIG. 5. FIG.
7 is a diagram showing a second embodiment of the present invention in which a Zener diode is used in place of the transistor of the lock mechanism coil circuit of FIG. 1. FIG.
8 is a waveform diagram showing a case where a neutral point voltage is changed with respect to the example of FIG.
[Explanation of symbols]
1 Electric disc brake device 4 Caliper 21 Motor 40 Controller 46 Neutral point 48 Motor driver 50 Lock mechanism coil 54 Control cable

Claims (2)

A multi-phase motor having a neutral point that advances a pair of brake pads facing each other across the disc rotor toward the disc rotor, a holding mechanism that holds thrust against the brake pad by the motor, and the holding mechanism the electric disk brake unit having a caliper enclosing an actuator for driving the said actuator is grounded one end, the electric disc brake device and the other end portion is connected to the neutral point.   2. The electric disc brake device according to claim 1, wherein a switching element is provided in a circuit including the neutral point and the actuator so that the actuator can be energized and cut off.

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