JPH09264351A - Electric-driven brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight and compact electric-driven brake capable of directly operating a brake piston through the straight motion of a rotor by providing a mechanism capable of the straight motion while a rotor part of an electric-driven motor is rotated. SOLUTION: A rotor 9 of an electric-driven motor 6 is kept movable in the rotational direction and in the axial direction, a ball ramp mechanism 16 is arranged between a housing to store the motor and the rotor 9, the rotor 9 is straight-moved in the axial direction by the rotation of the rotor 9 through the ball ramp mechanism 16, and a piston is operated by moving the rotor 9 in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric drive type brake, and more specifically, to a mechanism capable of linear movement while rotating a rotor portion of an electric motor as an actuator, which is directly driven by the linear movement of the rotor. The present invention relates to a lightweight, small-sized electric drive brake that can actuate a brake piston.

[0002]

2. Description of the Related Art Hydraulic brakes have been used in various vehicles such as passenger cars, large trucks, and even airplanes. In recent years, electrical brakes have been used because of the need to reduce vehicle weight and simplify the structure. The development of brake systems that operate independently (so-called by-wire brake systems) is becoming active. Such a braking system must have a structure capable of exerting a function suitable for each vehicle, be low-cost and practical.

As an example of such an electrically driven brake, there is JP-A 64-21229. This braking device includes a plunger that is translated so as to apply a brake pad to at least one driven member, and a nut that can be pressed against the plunger in a translational direction and screwed onto a screw. The screw is driven to rotate by the coaxial first gear that is rotated at the first angular velocity by such a motor to move the nut and the plunger to the first position.
In a drive device of a brake mechanism that moves at a linear speed, a second gear driven by the motor and fitted to rotate on a coaxial nut, and a plunger when a brake pad applies a load to a braked member. A device that connects the second gear and the nut in the rotational direction by the action of the load transmitted to the two gears is provided, and the nut and the second gear are rotationally driven by a motor at a second angular velocity lower than the first angular velocity. The present invention is characterized in that the nut and the plunger are moved at a second linear velocity proportional to the difference between the first and second angular velocities, and the applied load of the brake pad is positively amplified by the differential action.

[0004]

However, the above-mentioned electric drive type brake is driven by an electric motor, operates in the same manner, and has a highly efficient nut and screw as a mechanism for converting the rotational movement of the motor into a linear movement. Since a mechanism is required, the size of the device increases and the number of parts increases.
In addition, since the mechanical portion that converts the rotational movement of the electric motor as the actuator into the linear movement requires a component that performs the linear movement while regulating the rotation, the conversion efficiency deteriorates and the mechanism itself becomes large. I have a problem. Therefore, the present invention solves the above-mentioned problems by providing an electrically driven brake that uses a linear motion of a rotor portion of an electric motor as an actuator while rotating, and uses this electric motor. . Since this electric drive type brake linearly moves while the rotor itself rotates, parts that restrict rotation are not required, the device itself is extremely simplified, and the number of parts etc. is significantly reduced compared to conventional products. You can

[0005]

Therefore, the technical solution adopted by the present invention is to axially support the rotor that rotates by energizing the stator so as to be rotatable and movable in the axial direction, and to fix the rotor and the fixing member. 5, a ball ramp mechanism 16 is arranged between them, and the rotor is rotated to linearly move the rotor in the axial direction through the ball ramp mechanism.
An electrically driven brake, characterized in that it is configured to operate a piston by axial movement of the rotor,

A ball ramp mechanism 16 is arranged between the rotor 9 and a housing 5 for holding the rotor 9 of the electric motor 6 so as to be rotatable and movable in the axial direction, and the rotor 9 is rotated by the rotation of the rotor. The electrically driven brake is characterized in that the rotor is linearly moved in the axial direction via the ball ramp mechanism, and the piston is operated by the axial movement of the rotor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a wiring diagram and a sectional view of an electric drive type brake, and FIG. 2 shows an operating state of the electric drive type brake. FIG. In FIG. 1, 1 is a pedaling force provided on a brake pedal, a stroke sensor, 2 is an electronic control device, 3 is a speed sensor, 4 is a caliper, 5 is a housing (fixing member) formed in the caliper, and 6 is in the same housing. It is a built-in electric motor. In the electric drive type brake configured by these, the electronic control unit 2 operates the electric motor 6 by detecting that the driver operates the brake pedal by the pedaling force and the stroke sensor 1, and the rotor in the motor is linearly moved. It is possible to move (to be described later in detail) the piston in the figure, and to move a pair of friction elements (not shown) (not shown) in the directions to clamp the disc rotor and to exert a braking force. It is composed. The pedaling force / stroke sensor 1 may be a sensor that can detect either the pedaling force or the stroke.

The electric motor 6 has a stator 8 side including a coil 7 fixed in a bore 5a formed in the housing 5, and a rotor 9 is arranged in the stator 8.
The width of the stator 8 is formed to be slightly smaller than the width of the rotor 9 so that the rotor 8 does not protrude from the rotor 9 when the rotor 9 makes a linear motion as will be described later. As shown in the drawing, the rotor 9 is integrally formed with a first rotating shaft 9a and a second rotating shaft 9b. The first rotating shaft 9a is fitted to a piston 11 via a bearing 10 so as to be rotatable and slidable. And also second
The rotating shaft 9b is rotatably and slidably supported by the housing 5 via a bearing 13. The piston 11
Is slidably held in a bore 5a formed in the housing 5, and a return spring 14 is provided between the piston 11 and the rotor 9 to further transmit the axial movement of the rotor 9 to the piston 11. The thrust bearing 15 of FIG.

Further, between the rotor 9 and the housing 5, a well-known ball ramp mechanism 16 composed of a rotor, a housing, and balls sandwiched by these, as shown in the AA cross section in the drawing. Is arranged, and this mechanism causes the rotor 9 to linearly move while rotating as will be described later. The rotor 9
The moving distance in the linear direction is determined by the ball diameter of the ball ramp mechanism and the shape of the inclined groove (the inclined groove formed between the rotor and the housing) of the ball storage portion.

The operation of the electrically driven brake having the above structure will be described. When the stroke sensor 1 detects that the driver has stepped on the brake pedal, a current from the electronic control unit 2 causes a current to flow through the coil 7 of the electric motor 6 and the rotor 9 starts rotating. When the rotor 9 rotates, the ball ramp mechanism 16 causes the rotor 9 to rotate and move linearly. That is, when the rotor 9 rotates in the AA cross-sectional view, the inclined surface rides on the ball, whereby the rotor moves in the axial direction (linear direction) according to the rotation angle of the rotor 9.

The linear movement of the rotor at this time is transmitted to the piston 11 via the thrust bearing 15, and the piston 11 moves leftward in the figure to apply the brake (the state at this time is shown in FIG. 2). . When the brake pedal is released, the electric motor 6 reversely rotates, and the piston 11 returns to the initial state due to the action of the return spring and the interference between the brake pad and the disc rotor to release the braking force. Since the linear movement amount of the piston during brake operation is determined by the rotation angle of the rotor 9, the electronic control unit finely controls the rotation angle of the rotor based on the pedaling force, the input signal from the stroke sensor, or the speed sensor. To do.

As described above, according to the present invention, since the rotor in the electric motor can be linearly moved while rotating,
A linear motion conversion mechanism separate from the conventional electric motor is not required, and the mechanism of the brake device itself can be greatly simplified. Needless to say, the electric motor used in the electrically driven brake according to the present invention can be applied to an actuator having a mechanism in which a rotor rotates by energizing a magnetic field coil (stator). Furthermore, this brake device is based on signals from various sensors such as a speed sensor, and easily controls anti-lock control, traction control, by controlling the timing of brake operation by an electronic control device, regardless of the driver's will. Automatic brake control, vehicle stability control, etc. can be executed. Further, the linear motion mechanism of the rotor incorporating the ramp mechanism described in the present embodiment can naturally be used as an actuator for various linear motions.

[0013]

As described in detail above, according to the present invention, 1) by adopting a ball ramp mechanism between the rotor and the housing, the rotor can be linearly moved while rotating. , This eliminates the need for a special motion conversion mechanism. 2) Since the rotor and the housing form a part of the ball ramp mechanism, it is possible to reduce the number of parts and downsize the device. 3) The electric drive type brake of the present invention can be easily applied to various brake controls such as antilock control only by controlling the timing of brake operation by the electronic control unit. And other excellent effects.

[Brief description of drawings]

FIG. 1 is a wiring diagram and a sectional view of an electrically driven brake according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an operating state of the electrically driven brake of FIG.

[Explanation of symbols]

 1 pedaling force and stroke sensor 2 electronic control device 3 speed sensor 4 caliper 5 housing 6 electric motor 7 coil 8 stator 9 rotor 10, 13 bearing 11 piston 14 return spring 15 thrust bearing 16 ball ramp mechanism

Claims (6)

[Claims] 1. A shaft support 10 for rotatably and axially movable a rotor 9 which is rotated by energizing a stator 8.
In addition, a ball ramp mechanism 16 is arranged between the rotor and the fixed member 5, and rotation of the rotor causes the rotor to linearly move in the axial direction via the ball ramp mechanism 16 in the axial direction of the rotor. An electrically driven brake characterized in that the piston is actuated by the movement of the. 2. The electric drive type brake according to claim 1, wherein the fixing member is a housing 5 for accommodating a stator 8 and a rotor 9. 3. A ball ramp mechanism 16 is arranged between a rotor 5 for holding a rotor 9 of an electric motor 6 so as to be rotatable and movable in the axial direction and a rotor housing the motor 6 and the rotor 9. An electrically driven brake characterized in that the rotor is linearly moved in the axial direction via the ball ramp mechanism by rotation, and the piston is operated by the axial movement of the rotor. 4. The axial length of the rotor 9 is formed to be longer than the width of the stator, and the stator 8 is formed so as not to protrude beyond the rotor 9 even if the rotor 9 makes a linear motion. Claim 1 or claim 3 characterized in that
The electrically driven brake described in. 5. The ball ramp mechanism 16 includes a rotor,
The electric drive type brake according to claim 2 or 3, which is configured by a housing and a ball sandwiched between the housing and the housing. 6. The electrically driven brake according to claim 1, further comprising a thrust bearing housing provided between the rotor and the piston.