JP2022057287A - Electric parking brake device of vehicle - Google Patents

Abstract

To reduce complexity of control in a re-operation after interruption of the operation in an electric parking brake device.SOLUTION: An electric parking brake device applies parking brake by generating fastening force between a rotary member and a friction member. A controller for controlling an electric motor executes application control of supplying a normal rotation current-carrying amount to the electric motor when applying the parking brake, supplying the normal rotation current-carrying amount from the time when the supply is started to the specific time when the influence of the inrush current of the electric motor is eliminated, supplying the normal rotation current-carrying amount when the normal rotation current-carrying amount is less than an application threshold after the specific time, and stopping the normal rotation current-carrying amount when the normal rotation current-carrying amount is equal to or greater than the application threshold. The controller performs prediction determination on whether or not the fastening force becomes excessive in the request termination when the interruption is requested during execution of the application control, continues the application control when the prediction determination is confirmed, and interrupts the application control when the prediction determination is denied.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to an electric parking brake device for a vehicle.

Patent Document 1 states, "While the electric parking brake device is configured to be operable in response to an input from the driver, the load on the battery and waste of power when the engine is restarted due to idle stop control are reduced." For that purpose, "a starter 30 connected to the battery 80, an idle stop control unit 12 that automatically stops the engine and automatically restarts the engine by the starter, and an idle stop control unit 12 that responds to an input from the driver. An electric parking brake device 40 that includes an input means for generating an operation request, an electric motor 42 connected to the battery, and the electric motor is driven in response to the operation request, and a predetermined operation request. When the electric motor is in the driving state, the restart of the engine by the idle stop control unit is prohibited, and when the engine is being restarted by the idle stop control unit, the predetermined operation request is responded to. It includes an arbitration unit that prohibits the driving of the electric motor. "

In the device of Patent Document 1, restarting of the engine is prohibited when the electric parking brake device is in operation. On the other hand, if the engine is restarting, the operation of the electric parking brake device is prohibited. That is, the device on one side that has been operated first has priority, and the device on the other side is prohibited from operating. However, other devices such as the engine starting device request that the electric parking brake device be interrupted while the electric parking brake device is operating (that is, the power consumption of the electric motor MT is reduced) depending on the situation of the storage battery or the like. Request) may be made.

By the way, in the electric parking brake device, the parking brake is applied by the pressing force (referred to as "tightening force") on the rotating member (brake disc, brake drum) of the friction member (brake pad, brake lining, etc.). This tightening force is generated by the forward rotation drive of the electric motor. In the electric parking brake device, it is necessary to secure an appropriate tightening force even in the above-mentioned situation. For example, the electric motor is temporarily stopped in response to the interruption request, and then the electric motor is restarted at the end of the interruption request. At that time, a situation may occur in which the forward / reverse rotation of the electric motor is repeated so that an appropriate tightening force is secured.

Further, in the electric parking brake device, the tightening force is reduced by the reverse drive of the electric motor, and the parking brake is released. The reverse drive of the electric motor is controlled based on the drive time, but once the electric motor is stopped in response to the interruption request, the reference time point of the drive time may be unclear in the restart. Even in that case, a situation may occur in which the forward / reverse rotation of the electric motor is repeated so that the reference time point becomes clear. From the above viewpoint, it is desired that the electric parking brake device suppresses the complexity of control related to such restart (that is, repeated forward / reverse rotation of the electric motor).

Japanese Unexamined Patent Publication No. 2016-203872

It is an object of the present invention to provide an electric parking brake device capable of reducing the complexity of control in re-operation after interruption of operation.

The electric parking brake device according to the present invention drives an electric motor (MT) in the forward rotation direction (Da) and tightens the electric motor (MT) between the rotating member (KT) and the friction member (MS) provided on the wheels of the vehicle. It generates a force (Fa) to apply the parking brake, and includes a controller (ECU) that controls the electric motor (MT). When the parking brake is applied, the controller (ECU) supplies a normal rotation current amount (Ia) corresponding to the normal rotation direction (Da) to the electric motor (MT), and the normal rotation current amount (MT). The forward rotation energization amount (Ia) is supplied from the start time when the supply of Ia) is started to the specific time point at which the influence of the inrush current of the electric motor (MT) disappears, and after the specific time point, the normal rotation energization is performed. When the amount (Ia) is less than the applicable threshold amount (ix), the forward rotation energization amount (Ia) is supplied, and when the forward rotation energization amount (Ia) is greater than or equal to the applicable threshold amount (ix). The application control for stopping the forward rotation current amount (Ia) is executed.

In the electric parking brake device according to the present invention, when the interruption of the application control is required during the execution of the application control, the controller (ECU) has the tightening force (the tightening force) when the request is terminated. A prediction determination is made as to whether or not Fa) is excessive, and if the prediction determination is affirmative, the application control is continued, and if the prediction determination is negative, the application control is interrupted.

For example, the controller (ECU) calculates a deviation (hI) between the forward rotation energization amount (Ia) and the applicable threshold amount (ix) at the time when the interruption is requested, and the deviation (hI) is calculated. If it is equal to or greater than the threshold deviation (hx), the prediction determination is denied, and if the deviation (hI) is less than the threshold deviation (hx), the prediction determination is affirmed. Alternatively, the controller (ECU) calculates an application continuation time (Te), which is the time from the start time to the time when the interruption is requested, and the application continuation time (Te) is the continuation threshold time (te). If it is less than, the prediction determination may be denied, and if the application continuation time (Te) is equal to or longer than the continuation threshold time (te), the prediction determination may be affirmed.

According to the above configuration, when the prediction determination is denied, the application operation is interrupted, so that the decrease in the power supply voltage is suitably suppressed and the excessive tightening force Fa is not generated. Further, in the restart after the interruption of the application process, the electric motor MT is driven only in the forward rotation direction Da, so that the complexity of control is avoided. On the other hand, if the prediction determination is affirmed, the execution of the application control is continued even if there is a suspension request. As a result, the complexity of control when the application operation is restarted is eliminated, and the parking brake is quickly put into the application state.

The electric parking brake device according to the present invention is for driving an electric motor (MT) in the reverse direction (Db) to release the parking brake, and a controller (ECU) for controlling the electric motor (MT). Be prepared. When the parking brake is released, the controller (ECU) determines the contact cancellation state in which the rotating member (KT) and the friction member (MS) do not come into contact with each other. When the release threshold time (tk) is reached, the release control for stopping the drive of the electric motor (MT) is executed. Then, the controller (ECU) continues the release control when the release control is requested to be interrupted after the determination point, and when the release control is requested to be interrupted before the determination point. Interrupts the release control.

According to the above configuration, when the contact cancellation state is not determined, the energization of the electric motor MT is immediately stopped, so that the decrease in the power supply voltage is suitably suppressed and the excessive displacement of the member is avoided. To. Further, in the restart after the interruption of the release process, the electric motor MT is driven only in the reverse direction Db, so that the complexity of control is avoided. On the other hand, when the contact cancellation state is determined, the execution of the release control is continued even if there is a suspension request. As a result, the complexity of motor control when the release operation is restarted is eliminated, and the parking brake is quickly released.

It is an overall block diagram for demonstrating the embodiment of the electric parking brake device EP. It is a schematic diagram for demonstrating the detail of the electric actuator DN. It is a flow diagram for demonstrating the process of application control and release control. It is a time series diagram for demonstrating the operation of application control and release control. It is a flow diagram for demonstrating the process of application interruption control. It is a time series diagram for demonstrating the operation of application interruption control. It is a flow diagram for demonstrating the process of release interruption control. It is a time-series diagram for explaining the operation of the release interruption control.

Hereinafter, an embodiment of the electric parking brake device EP for a vehicle according to the present invention will be described with reference to the drawings.

<Symbols of constituent members, subscripts at the end of symbols, and directions of movement / movement>
In the following description, components, elements, signals, etc. with the same symbol, such as "MT", have the same function. In the direction of movement / movement of the members (friction member MS itself, parking cable CB, output member SB, end member EN, etc.) related to the friction member MS (including the brake lining BL described later), the "forward direction Ha" is friction. Corresponding to the direction in which the member MS approaches the rotating member KT (including the brake drum BD described later), the "backward direction Hb (direction opposite to the forward direction Ha)" corresponds to the direction in which the friction member MS moves away from the rotating member KT. handle. Therefore, when the member related to the friction member MS is moved in the forward direction Ha, the pressing force (also referred to as “tightening force”) Fa, which is the force with which the friction member MS is pressed against the rotating member KT, is increased, and the braking force is increased. Is increased. On the contrary, when the member related to the friction member MS is moved in the receding direction Hb, the tightening force Fa is reduced and the braking force is reduced.

In the rotation direction of the electric motor MT, the forward rotation direction Da of the electric motor MT corresponds to the movement of the forward direction Ha of each member. Further, the reverse rotation direction Db (rotational direction opposite to the normal rotation direction Da) of the electric motor MT corresponds to the backward direction Hb of each member. That is, when the electric motor MT is rotationally driven in the forward rotation direction Da, the friction member MS is moved in the forward direction Ha, the tightening force Fa is increased, and the braking force is increased. On the contrary, when the electric motor MT is rotationally driven in the reverse direction Db, the friction member MS is moved in the backward direction Hb, the tightening force Fa is reduced, and the braking force is reduced.

Regarding the energization amount (for example, current value) of the electric motor MT, the energization amount corresponding to the forward rotation direction Da is the "forward rotation energization amount Ia", and the energization amount corresponding to the reverse rotation direction Db is the "reverse energization amount Ib". They are called each. The forward rotation energization amount Ia corresponds to the case where a positive voltage is applied to the electric motor MT, and the reverse rotation energization amount Ib corresponds to the case where a negative voltage is applied to the electric motor MT. Therefore, the forward and reverse energization amounts Ia and Ib are different in the direction in which the current flows (that is, the energization direction).

<Brake device DB>
The braking device DB is provided on the wheels of the vehicle and generates braking force on the wheels (for example, the rear wheels). In the braking device DB, the friction member MS (brake pad, brake lining, etc.) is pressed against the rotating member KT (brake disc, brake drum, etc.) to decelerate the vehicle (referred to as "deceleration braking force Fx"). , And a braking force (referred to as "parking braking force Fp") for maintaining the stopped state of the vehicle is generated.

The braking device DB will be described with reference to the overall configuration diagram of FIG. 1 by taking a known drum type brake as an example. The deceleration braking force Fx is generated by using the pressure (hydraulic pressure) of the braking fluid in the wheel cylinder (not shown) as a power source. Further, the parking braking force Fp is generated by using the electric motor MT included in the electric actuator (simply also referred to as “actuator”) DN as a power source. Then, the electric motor MT is energized and driven by a controller ECU that receives electric power from a power source (generator AL, storage battery BT) mounted on the vehicle. The deceleration braking force Fx is used for the service brake, and the parking braking force Fp is used for the parking brake.

《Activation of service brake》
The braking device DB is composed of a brake drum BD, a brake shoe BSa, BSb, a wheel cylinder (not shown), and a backing plate BP so as to generate a deceleration braking force Fx.

In the braking device DB, the brake drum BD (an example of the "rotating member KT") is fixed to the wheel so as to rotate integrally with the wheel about the rotation axis Jk of the wheel. The braking device DB is provided with two brake shoes BSa and BSb. The two brake shoes BSa and BSb are extended in an arc shape along the inner peripheral surface Mn of the cylindrical brake drum BD. Brake lining BL (an example of "friction member MS") is printed on the brake shoes BSa and BSb. The braking device DB is provided with a disk-shaped backing plate BP. Wheel cylinders, brake shoes BSa, BSb, etc. (not shown) are arranged outside the backing plate BP in the vehicle width direction.

The wheel cylinder presses the two brake shoes BSa and BSb against the inner peripheral surface Mn of the brake drum BD. As a result, a braking torque is applied to the brake drum BD by friction between the brake lining BL provided on the brake shoes BSa and BSb and the brake drum BD (particularly, the inner peripheral surface Mn), and as a result, the wheels have a braking force. Generates Fx. That is, the wheel cylinder is used for decelerating the vehicle while traveling.

Specifically, the lower ends of the brake shoes BSa and BSb are rotatably supported by the backing plate BP around the two rotation positions Ja and Jb. The wheel cylinder is supported by the upper end of the backing plate BP. The wheel cylinder has two movable parts (pistons) that can project in the front-rear direction of the vehicle, and these movable parts are projected by the pressure of the braking fluid in the wheel cylinder. The protrusion of the movable portion pushes the upper end portions of the brake shoes BSa and BSb, and the brake lining BL is pressed against the inner peripheral surface Mn of the brake drum BD. The friction between the brake lining BL and the inner peripheral surface Mn applies braking torque to the brake drum BD, and the wheels are braked. The braking device DB is provided with a returning member (for example, a coil spring) (not shown), and when the pressing of the brake shoes BSa and BSb is released by the returning member, the brake shoes BSa and BSb brake. It is moved away from the inner peripheral surface Mn of the drum BD.

《Activation of parking brake》
The braking device DB includes an electric actuator DN, a parking lever PL, a parking cable CB, and a shoe strut ST in addition to the above-mentioned components (brake drum BD, etc.) so as to generate a parking braking force Fp. ..

The electric actuator DN is used for braking during parking as an actuator for driving the brake shoes BSa and BSb. Specifically, the two brake shoes BSa and BSb are moved by the electric actuator DN driven by the electric motor MT so as to generate the parking braking force Fp. The details of the actuator DN will be described later. The actuator DN may be used for braking during traveling (that is, service braking).

The parking lever PL is provided between one of the two brake shoes BSa and BSb (for example, the brake shoe BSa) and the backing plate BP so as to overlap the brake shoe BSa and the backing plate BP. ing. The parking lever PL is rotatably supported by the brake shoe BSa about the rotation axis Jp. In the parking lever PL, the parking cable CB is connected to the lower end Pb on the side far from the rotation shaft Jp.

A shoe strut ST is provided between the two brake shoes BSa and BSb. When the parking brake is applied, the parking cable CB is pulled in the forward direction Ha by the actuator DN. As a result, the parking lever PL tends to rotate about the rotation axis Jp, so that the shoe strut ST stretches between the two brake shoes BSa and BSb. The tension of the shoe strut ST pushes one brake shoe BSb, and the reaction force pushes the other brake shoe BSa. As a result, the brake lining BL of the brake shoes BSa and BSb is pressed against the inner peripheral surface Mn of the brake drum BD, and a parking braking force Fp is generated.

When the parking brake is released, the tension of the parking cable CB is reduced by the actuator DN, and the tightening force Fa (pushing pressure) of the brake lining BL with respect to the inner peripheral surface Mn of the brake drum BD is reduced. Then, the inner peripheral surface Mn of the brake drum BD and the brake lining BL are finally separated by the return member.

<Electric parking brake device EP>
An embodiment of the electric parking brake device EP according to the present invention will be described with reference to a schematic view including a partial cross-sectional view of FIG. A vehicle equipped with the electric parking brake device EP is provided with a parking brake switch (simply also referred to as a "parking switch") SW. The parking switch SW is a switch operated by the driver, and an on or off signal Sw (referred to as “parking signal”) is output to the electronic control unit ECU (also referred to as “controller”). That is, the parking switch SW operated by the driver indicates the operation (applicable operation or release operation) of the parking brake that maintains the stopped state of the vehicle. Specifically, when the parking signal Sw is ON, the application (operation) is instructed so that the parking brake is activated. On the contrary, in the OFF state (OFF) of the parking signal Sw, the release (operation) is instructed so that the parking brake does not work.

The vehicle is provided with a plurality of controllers (electronic control units) ECA and ECB in addition to the controller ECU for the electric parking brake device EP. These controllers are connected by a communication bus BS so that signals (detection values, calculated values, etc.) are shared. For example, the vehicle body speed Vx, the operation amount Ap of the acceleration operation member (for example, the accelerator pedal), and the like are input to the controller ECU from the communication bus BS. The vehicle body speed Vx and the acceleration operation amount Ap are used in the automatic mode of the electric parking brake device EP.

During the execution of application control or release control, another controller ECA or ECB may send a request for operation interruption to interrupt the control to the controller ECU via the communication bus BS. The other controllers ECA and ECB share a power source (power source, storage battery BT, generator AL) with the electric parking brake device EP (that is, controller ECU), and control a large electric motor and solenoid. It belongs to (system). For example, the device includes an engine starting device, a shift control device, and the like.

When a large electric device (for example, an electric motor or a solenoid) is started (when the power is turned on), a large current temporarily exceeds the rated current value at the initial stage. The large current is referred to as "inrush current" or "starting current". The above-mentioned operation interruption request is made in order to prevent the voltage of the power supply BT from dropping and restarting each device due to the inrush current. For example, the operation interruption request (request for start, continuation, and end of interruption) is performed by the control flags FL (for application control) and FK (for release control). The control flags FL and FK are also referred to as "request flags (or interruption flags)". Specifically, "no interruption request" is displayed at "FL, FK = 0", and "with interruption request" is displayed at "FL, FK = 1". Therefore, the interruption request is started when the request flags FL and FK are changed from "0" to "1", and the interruption request is continued when the request flags FL and FK are maintained at "1", and the request flag FL is used. , The interruption request is terminated by the transition of FK from "1" to "0".

The electric parking brake device EP is composed of an electric actuator DN and a controller ECU. The actuator DN generates a parking braking force Fp by the electric motor MT. Hereinafter, the actuator DN will be described. The feature of the electric parking brake device EP according to the present invention is a control algorithm programmed in the controller ECU.

<< Electric Actuator DN >>
The electric actuator DN is fixed to the backing plate BP on the side opposite to the brake shoes BSa and BSb and on the inner surface of the backing plate BP in the vehicle width direction. A parking cable CB is extended from the actuator DN. The parking cable CB penetrates the through hole provided in the backing plate BP and is connected to the parking lever PL (particularly, the lower end portion Pb).

The actuator DN includes a housing HG, an electric motor MT, a speed reducer GS, a power conversion mechanism HN, a parking cable CB, and an end member EN. The housing HG supports the electric motor MT, the speed reducer GS, and the power conversion mechanism HN, and covers these components. The electric motor MT is a power source for generating a parking braking force Fp. The electric motor MT is driven by the controller ECU.

The reducer GS is composed of a plurality of gears. For example, the speed reducer GS includes a large diameter gear DK and a small diameter gear SK. A small diameter gear SK is fixed to the output shaft SF of the electric motor MT. A large diameter gear DK is meshed with the small diameter gear SK. The output of the electric motor MT (that is, the rotational power of the output shaft SF) is decelerated via the speed reducer GS. The rotational power of the decelerated electric motor MT is input to the power conversion mechanism HN.

The power conversion mechanism HN is composed of an input member NB, an output member SB, and a detent member MD. A large diameter gear DK is fixed to the input member NB. Therefore, the input member NB is rotationally driven integrally with the large diameter gear DK. The input member NB has a cylindrical shape, and a male screw Oj is formed on the outer peripheral portion thereof. The input member NB is a "bolt member".

The male screw Oj of the input member NB is screwed into the female screw Mj of the output member SB. Specifically, the output member SB has a tubular shape, and a female screw Mj is formed on the inner peripheral portion (inside of the through hole) thereof. The output member SB is a "nut member". In the power conversion mechanism HN, the input member NB (bolt member) and the output member SB (nut member) are meshed with each other, and the rotational power of the electric motor MT is converted into linear power. Here, as the power conversion mechanism HN, a self-locking mechanism (a mechanism having zero reverse efficiency) is adopted.

The rotation stop member MD fixed to the housing HG regulates the rotational movement of the output member SB. That is, the detent member MD detents the output member SB and guides the linear movement of the output member SB. For example, a flange portion Fl is provided on the outer peripheral portion of the output member SB, and at least one two chamfers are formed on the flange portion Fl. The detent member MD has a tubular shape, and its inner surface is processed so that it can be fitted into the two chamfers of the flange portion Fl. The rotational movement of the output member SB is restricted by sliding the two chamfered portion (flat surface) of the flange portion Fl and the two chamfered portion (flat surface) of the detent member MD. As a result, the output member SB is linearly moved along the rotation axis Jn of the input member NB. The detent member MD is formed with an end face Mb on the side opposite to the side on which the large diameter gear DK is fixed.

The parking cable CB penetrates the inner peripheral surface (through hole) of the input member NB and extends in the direction of the rotation axis Jn. One end of the parking cable CB is connected to a parking lever PL which is a movable member so as to operate the brake shoes BSa and BSb. An end member EN is coupled to the other end of the parking cable CB. The end member EN has a tubular portion and a flange portion. By crimping the tubular portion of the end member EN from the outside, the parking cable CB and the end member EN are joined (fixed). The flange portion (particularly, the end face Ma) of the end member EN projects radially outward from the end portion Mc of the output member SB and can come into contact with the end portion Mc. Further, the flange portion (particularly, the end face Ma) can come into contact with the end face Mb of the detent member MD.

In FIG. 2, the state (a) shown on the left side of the rotation axis Jn (dashed-dotted line) of the input member NB illustrates a state in which the electric motor MT is driven and tension is applied to the parking cable CB. In the state (a), the brake shoes BSa and BSb are pressed against the brake drum BD, and the wheels are restrained by the electric parking brake device EP (that is, a parking braking force Fp is applied to the wheels). The state (a) is called an "applied state", and the parking brake is in effect.

In FIG. 2, the state (b) shown on the right side with respect to the rotation axis Jn of the input member NB illustrates a state in which the tension on the parking cable CB is released. Here, the end member EN and the output member SB are not integrated and are configured to be separable in the axial direction. In the state (b), the brake shoes BSa and BSb are separated from the brake drum BD, and the parking braking force Fp does not act on the wheels. The state (b) is called a "release state", and the parking brake is not working.

<< Controller ECU >>
The electric motor MT is controlled by the controller ECU (electronic control unit), and the actuator DN is driven. The controller ECU includes an electric circuit board on which a microprocessor MP or the like is mounted, and a control algorithm programmed in the microprocessor MP. Power is supplied to the controller ECU from the storage battery BT charged by the generator AL. The controller ECU executes the above control algorithm by the electric power from the storage battery BT, and energizes the electric motor MT. As described above, the storage battery BT also supplies electric power to the controllers ECA and ECB of other systems.

In the controller ECU, the drive signal Mt for controlling the electric motor MT is calculated based on the control algorithm in the microprocessor MP. Further, the controller ECU is provided with a drive circuit DR so as to drive the electric motor MT. In the drive circuit DR, a bridge circuit is formed by switching elements (power semiconductor devices such as MOS-FETs and IGBTs). The energized state of each switching element is controlled according to the drive signal Mt, and the output of the electric motor MT is controlled. The drive circuit DR is provided with an energization amount sensor IA that detects an actual forward rotation energization amount Ia (corresponding to the forward rotation direction Da) and a reverse rotation energization amount Ib (corresponding to the reverse rotation direction Db) of the electric motor MT. For example, a current sensor is adopted as the energization amount sensor IA, and the supply currents Ia and Ib to the electric motor MT are detected. Further, the drive circuit DR is provided with a voltage sensor VA that detects the supply voltage value Va (power supply voltage value) to the electric motor MT.

The application operation of the parking brake (that is, the operation for applying the parking brake and the transition from the release state (b) to the application state (a)) will be described. The control of the actuator DN when the parking brake is applied is called "applied control". When the parking switch SW is operated and the parking signal Sw is switched from off to on, application of a positive voltage to the electric motor MT is started. The forward rotation energization amount Ia is supplied to the electric motor MT, and the electric motor MT is rotationally driven in the forward rotation direction Da. This rotational power is transmitted to the input member NB via the speed reducer GS. The rotational power of the input member NB is converted into the linear power of the output member SB. Here, the output member SB is guided by the detent member MD (particularly, the two chamfered portions of the flange portion Fl and the inner peripheral portion Mm) to move along the rotation axis Jn (movement in the forward direction Ha). When the parking brake is applied, the output member SB is moved in the forward direction Ha. When the end portion Mc of the input member NB and the end surface Ma of the end member EN are not in contact with each other, no tension is applied to the parking cable CB. Therefore, in the electric motor MT, an output corresponding to the frictional force (sliding friction) with respect to the movement of the input member NB, the output member SB, the detent member MD, and the like is generated.

Since the parking cable CB and the end member EN are fixed, tension is generated in the parking cable CB when the end portion Mc of the input member NB and the end surface Ma of the end member EN come into contact with each other. By moving the end member EN in the forward direction Ha, the tension of the parking cable CB is increased. As a result, the tightening force Fa of the brake lining BL with respect to the brake drum BD is increased, and the parking braking force Fp is increased. Since the torque output of the electric motor MT is substantially proportional to the forward rotation energization amount Ia, the energization to the electric motor MT is stopped when the forward rotation energization amount Ia reaches the applicable threshold amount ix. Here, the application threshold amount ix is a threshold value corresponding to the forward rotation energization amount Ia for terminating the application control (application operation), and is a predetermined value (constant) set in advance. The applicable threshold amount ix is set to a value at which the pressed state between the brake lining BL and the brake drum BD can be sufficiently secured so that the parking brake is effective. Since the power conversion mechanism HN is self-locking, the tension of the parking cable CB is maintained even after the energization of the electric motor MT is stopped, and the parking brake is in effect (that is, the applied state).

Next, the release operation of the parking brake (that is, the operation of disabling the parking brake and the transition from the applied state (a) to the release state (b)) will be described. The control of the actuator DN when the parking brake is released is called "release control". When the parking switch SW is operated and the parking signal Sw is switched from on to off, application of a negative voltage to the electric motor MT is started. The reverse energization amount Ib is supplied to the electric motor MT, and the electric motor MT is rotationally driven in the reverse direction Db. In the electric motor MT, the output member SB is moved in the backward direction Hb (direction opposite to the forward direction Ha (opposite direction)) by the rotational power of the electric motor MT. As a result, the tension of the parking cable CB is reduced, and the tightening force Fa (resulting in the parking braking force Fp) is reduced. Then, the end face Ma of the end member EN comes into contact with the end portion Mb of the detent member MD. Up to this point, the end member EN and the output member SB are moved together. That is, when the parking brake is released (when it is not effective), the output member SB is moved in the backward direction Hb.

Further, when the electric motor MT is driven in the reverse direction Db, the end member EN and the output member SB are separated (separated). As a result, the tension of the parking cable CB is set to approximately "0 (zero)". After that, the electric motor MT is driven in the reverse direction Db based on the time T. Then, in a state where the end portion Mk of the output member SB (the side opposite to the end portion Mc) and the portion Md of the input member NB have a certain distance (that is, the gap Lr), the electric motor MT is reached. The energization of the output member SB is stopped, and the movement of the output member SB in the backward direction Hb is stopped. In other words, when the movement of the output member SB is stopped, there is a gap between the end portion Mk of the output member SB and the portion Md of the input member NB, so that a stopper or the like is not required.

<Processing of application control and release control>
The application control and the release control of the electric parking brake device EP will be described with reference to the flow chart of FIG.
≪Application control≫
First, the application control process will be described with reference to the flow chart of FIG. 3A. The "applied control" is the control that is the basis (reference) for transitioning from the released state in which the parking brake is not effective to the applied state in which the parking brake is effective. That is, the application control is a control for applying and operating the parking brake, and is started when the parking signal Sw is switched from off to on. Here, switching the parking signal Sw from off to on is called an "application instruction". The application control is performed by the drive control of the electric motor MT. Specifically, in the application control, the electric motor MT is energized (for example, a positive voltage is applied), and the electric motor MT is driven in the forward rotation direction Da.

In step S110, the parking signal Sw and various signals including the actual energization amounts Ia and Ib are read. For example, the forward rotation and reverse rotation energization amounts Ia and Ib (actual values) are detected by the energization amount sensor IA (current sensor) provided in the drive circuit DR. Further, the energization amount sensor IA may be built in the electric motor MT.

In step S120, the electric motor MT is energized. Specifically, a positive sign (+) voltage is applied to the electric motor MT at the time of the application instruction (corresponding calculation cycle) when the parking signal Sw transitions from off to on. After the energization is started, the application of the positive voltage to the electric motor MT is continued in step S120. As a result, the electric motor MT continues to be driven in the forward rotation direction Da.

In step S130, "whether or not it is an inrush current section" is determined. The "inrush current" is a large current that temporarily exceeds the steady current value at the initial stage when a power is turned on to an electric device (for example, an electric motor MT), and is a "starting current". Also called "electric current". The "inrush current section" is a section (period) in which the inrush current can occur. The determination of the inrush current section is performed in order to eliminate the influence of the inrush current in the determination in step S140.

For example, in step S130, "whether or not it is an inrush current section" is determined based on the actual amount of normal rotation energization Ia. In step S130, after the energization of the electric motor MT is started, the previous value Ia [n-1] of the forward rotation energization amount Ia and the current value Ia [n] of the forward rotation energization amount Ia are compared. (Here, "n" represents a calculation period). Then, from the start of energization of the electric motor MT, in the actual normal rotation energization amount Ia, the change amount dIa with respect to the time T (the time derivative value of the normal rotation energization amount Ia, also referred to as "applied energization change amount"). The end of the inrush current section is determined when the state of being less than the predetermined change amount dj (referred to as “application determination change amount”) is continued over the application determination time tj. Here, the application determination time tj and the application determination change amount dj are preset constants (predetermined values). In other words, "when the applied energization change amount dIa is equal to or greater than the application determination change amount dj" and "even if the applied energization change amount dIa is less than the application determination change amount dj", the application determination time tj has elapsed. If not, it is determined that it is an inrush current section.

Moreover, the time (period) in which the inrush current flows is known. Therefore, in step S130, the end of the inrush current section may be determined based on the elapse of the specific application time tm from the time when the electric motor MT is energized. Specifically, the application duration Tj is calculated (integrated) from the time when the electric motor MT is energized, and when the application duration Tj is less than the specific application time tm, it is "inrush current section". Is determined. On the other hand, when the application duration Tj is equal to or longer than the specific application time tm, it is determined that the application duration is not an inrush current section. Here, the specific application time tm is a threshold value corresponding to the application duration Tj for determining the end of the inrush current section, and is a predetermined value (constant) set in advance.

If it is determined in step S130 that it is an inrush current section, the process is returned to step S110. On the other hand, if it is determined in step S130 that "it is not an inrush current section", the process proceeds to step S140. Here, the time point at which step S130 is denied for the first time and the process proceeds to step S140 (corresponding calculation cycle) is referred to as a "specific time point". Therefore, the period from the start time of energization to the specific time point corresponds to the "inrush current section".

In step S140, "whether or not the actual forward rotation energization amount Ia is equal to or greater than the applicable threshold amount ix" is determined based on the comparison between the forward rotation energization amount Ia and the applied threshold amount ix. The applicable threshold amount ix is preset as a value (predetermined constant) corresponding to a sufficient pressing state of the brake lining BL and the brake drum BD so that the parking brake is effective. If “Ia ≧ ix” and step S140 is affirmed, the process proceeds to step S150. On the other hand, if "Ia <ix" and step S140 is denied, the process is returned to step S110.

In step S150, the application of the positive voltage to the electric motor MT is stopped, and the energization is stopped. That is, when the forward rotation energization amount Ia reaches the application threshold amount ix, the application control is terminated in step S150. Since the power conversion mechanism HN is self-locking, the parking brake is maintained in an effective state (that is, an applied state) even when the energization of the electric motor MT is stopped.

As described above, in the application control, the period from the start time when the energization to the electric motor MT is started to the specific time point when the influence of the inrush current of the electric motor MT disappears (that is, the inrush current section) is The determination in step S140 (comparison determination between the normal rotation current amount Ia and the applicable threshold amount ix) is not performed. Therefore, in the inrush current section, the forward rotation current amount Ia is supplied to the electric motor MT regardless of the magnitude relationship between the forward rotation energization amount Ia (the energization amount corresponding to the normal rotation direction Da) and the applicable threshold amount ix ( Is energized). After the specific time point at which the inrush current section ends, the normal rotation current amount Ia and the applicable threshold amount ix are compared. When the forward rotation energization amount Ia is less than the applicable threshold amount ix, the forward rotation energization amount Ia is supplied to the electric motor MT. Then, when the forward rotation energization amount Ia becomes equal to or more than the applicable threshold amount ix, the energization of the normal rotation energization amount Ia to the electric motor MT is stopped.

In the application control, basically, when “Ia ≧ ix” is satisfied, the forward rotation energization amount Ia is set to “0”. However, due to the inrush current, a situation may occur in which the condition of "Ia ≧ ix" is satisfied. If the application control is terminated in this situation, the tightening force Fa becomes insufficient. In order to avoid this situation, in the electric parking brake device EP, in the inrush current section (the period from the above start time to the specific time point), the comparison between the normal rotation current amount Ia and the applicable threshold amount ix is prohibited, and they are prohibited. Regardless of the magnitude of, a positive voltage is applied and the forward rotation current amount Ia continues to be supplied. As a result, the influence of the inrush current is eliminated, so that a sufficient tightening force Fa is always secured and the parking brake is put into the applied state.

≪Release control≫
Next, the release control process will be described with reference to the flow chart of FIG. 3 (b). "Release control" is a control that is a source (reference) for transitioning from an applied state in which the parking brake is effective to a release state in which the parking brake is not effective. That is, the release control is a control for releasing and operating the parking brake. The release control is started when the parking signal Sw is switched from on to off. Here, switching the parking signal Sw from on to off is called a "release instruction". The release control is performed by the drive control of the electric motor MT. Specifically, in the release control, energization (for example, application of a negative voltage) is performed on the electric motor MT, and the electric motor MT is driven in the reverse direction Db.

In step S210, the parking signal Sw and various signals including the actual energization amounts Ia and Ib are read. For example, the forward and reverse current energization amounts Ia and Ib (actual current values) are detected by the energization amount sensor IA (current sensor) provided in the drive circuit DR. Further, the energization amount sensor IA may be built in the electric motor MT.

In step S220, the electric motor MT is energized. Specifically, a voltage having a negative sign (−) is applied to the electric motor MT at the time of the release instruction (corresponding calculation cycle) in which the parking signal Sw transitions from on to off. After the energization is started, the application of the negative voltage to the electric motor MT is continued in step S220. As a result, the electric motor MT continues to be driven in the reverse direction Db.

In step S230, it is determined whether or not the contact is canceled (referred to as "contact cancellation determination"). The "contact cancellation state" is a state in which the brake lining BL (that is, the rotating member KT) and the brake drum BD (that is, the friction member MS) that were in the contact state do not come into contact with each other. For example, the contact cancellation determination is performed based on "whether or not the reverse energization amount Ib is constant". That is, the contact cancellation state is determined based on the fact that the reverse energization amount Ib is constant (constant state of the reverse energization amount Ib).

In a state where the brake lining BL (friction member MS) and the brake drum BD (rotating member KT) do not come into contact with each other (contact cancellation state), the tension of the parking cable CB becomes substantially zero and the reverse energization amount Ib becomes constant. .. At this time, the output of the electric motor MT is the friction (sliding) of the power transmission mechanism (electric motor MT, speed reducer GS, input member NB, output member SB, parking cable CB, etc.) from the electric motor MT to the friction member MS. Used only for dynamic friction). In other words, the magnitude of the reverse energization amount Ib supplied to the electric motor MT in the contact-dissolved state is a value corresponding to the friction of the power transmission member.

For example, the "constant state of the reverse energization amount Ib (that is, the contact cancellation state)" is a state in which the reverse energization amount Ib is within a preset predetermined range (within the range of the contact determination amount ih). It is determined when it is continued for the time th (referred to as "contact determination time"). Further, in the contact cancellation state, the change amount dIb (the time derivative value of the reverse energization amount Ib, also referred to as "release energization change amount") with respect to the time T is equal to or less than the contact determination change amount dx in the reverse energization amount Ib. The state may be determined when the state is maintained over the determination time th. Here, the contact determination amount ih, the contact determination time th, and the contact determination change amount dx are predetermined values (constants) set in advance.

When it is determined in step S230 that "the state of contact cancellation (also referred to as" contact cancellation confirmation ")", the control flag FF (also referred to as "contact determination flag") is set to "1". Here, the contact determination flag FF is displayed at "0" that "the contact is not in the contact cancellation state or the contact state is unknown" (also referred to as "contact cancellation unconfirmed"), and is displayed at "1". "Confirmation of contact cancellation" is expressed. The contact determination flag FF is set to "0 (contact cancellation undecided)" as an initial value before the execution of the release control is started.

In order to improve the robustness of the contact cancellation determination, "the reverse energization amount Ib is equal to or greater than the release amount ik" may be added to the determination condition as a permission condition. For example, when the transmission efficiency of the power transmission member (reducer GS, power conversion mechanism HN, etc.) is lowered, the amount of change dIb (that is, the increasing gradient of the reverse energization amount Ib) with respect to the time T of the reverse energization amount Ib is small. Therefore, even if the brake lining BL is still in contact with the brake drum BD, a situation may occur in which a constant state of the reverse energization amount Ib is determined. Therefore, in the state of "Ib <ik", the execution of the contact cancellation determination is prohibited, and the execution of the contact cancellation determination is permitted only when the state of "Ib ≧ ik" is reached. Here, the release amount ik is a predetermined value (negative constant) set in advance. The release amount ik is when the electric motor MT is driven with no load in a normal state (normal temperature) (that is, sliding friction of the electric motor MT, the speed reducer GS, the input member NB, the output member SB, the detent member MD, etc.). It is set to a value slightly larger than the energization amount corresponding to.

If step S230 is denied, processing is returned to step S210. On the other hand, if step S230 is affirmed, the process proceeds to step S240. Here, the time point at which step S230 is affirmed for the first time (corresponding calculation cycle) is referred to as a "determined time point".

In step S240, the release duration Tk is calculated. The release duration Tk is the time from the time when step S230 is affirmed for the first time (corresponding calculation cycle). In other words, the release duration Tk is the time elapsed from this starting point (reference point) at the time (transition) when the contact cancellation is confirmed (transition) from the contact cancellation undetermined state. Is.

In step S250, it is determined whether or not the release duration Tk is equal to or longer than the release threshold time tk. Here, the release threshold time tk is a threshold value corresponding to the release duration Tk for terminating the release control (release operation), and is a predetermined value (constant) set in advance. If "Tk <tk" and step S250 is denied, processing is returned to step S210. On the other hand, if “Tk ≧ tk” and step S250 is affirmed, the process proceeds to step S260. In step S260, the application of the negative voltage to the electric motor MT is stopped, and the energization is stopped. That is, in step S260, the drive of the electric motor MT is stopped, and the release control is terminated.

As described above, in the electric parking brake device EP, when the parking brake is released, the reverse energization amount Ib to the electric motor MT becomes constant at the definite point in time when the contact cancellation state is determined for the first time (for example, the reverse energization amount Ib to the electric motor MT becomes constant. At the time when the release threshold time tk has elapsed from the time point) (corresponding calculation cycle), the energization of the electric motor MT is stopped, and the drive of the electric motor MT is stopped. As a result, the movement of the output member SB in the receding direction Hb is completed, and the output member SB comes to rest. At this time, the end portion Mk of the output member SB and the portion Md of the input member NB have a gap Lr and are not in contact with each other. In other words, since the release control of the electric parking brake device EP is performed according to the time T, it is not necessary to restrict the movement of the output member SB in the backward direction Hb by the contact with the movement limiting member such as the stopper. ..

In the state where the electric parking brake device EP is released, the electric motor MT and the members (output member SB, input member NB, etc.) driven by the electric motor MT are in the non-restraint state (free state). Specifically, the male screw Oj and the female screw Mj of the power conversion mechanism HN are not tightened in the parking brake release state (that is, the parking brake is not working). Therefore, when the parking brake instruction is given again and the application control of the electric parking brake device EP is started, it is not necessary to supply electric power to release the tightening, and the electric power of the electric motor MT is reduced. Power saving is achieved. Further, since the movement limiting member of the output member SB can be omitted, the device can be made smaller and lighter.

<Operation of application control and release control>
The operation of the application control and the release control will be described with reference to the time-series diagram of FIG. 4 (the diagram showing the change of the state quantity with respect to the transition of time T). In the application control, the forward rotation energization amount Ia is supplied so as to drive the electric motor MT in the forward rotation. On the other hand, in the release control, the reverse energization amount Ib is supplied so as to reversely drive the electric motor MT. In the relationship between the forward rotation energization amount Ia and the reverse rotation energization amount Ib, the forward rotation energization amount Ia has a positive sign (+), whereas the reverse rotation energization amount Ib has a negative sign (−). That is, the forward rotation energization amount Ia and the reverse rotation energization amount Ib are different in the energization direction (for example, the direction in which the current flows). In the example, the inrush current section of step S130 is determined based on the application duration Tj from the start time of energization. Further, in the release control, a permission condition of "Ib ≧ ik (<0)" is provided, but this can be omitted.

≪Applicable operation≫
At the time point t0, the parking switch SW is changed from the off state to the on state (that is, the application instruction is given), and the application control is started. At time point t0, a positive voltage is applied to the electric motor MT by application control so that the electric motor MT rotates in the normal direction. As a result, energization corresponding to the forward rotation direction Da of the electric motor MT is started. From the time point t0, the calculation of the application duration Tj is started. Here, the time point t0 corresponds to the "start time point" at which the energization of the forward rotation energization amount Ia is started.

Immediately after the time point t0, an inrush current (starting current) flows through the electric motor MT. As a result, the forward rotation energization amount Ia rises to the peak value ia and then decreases. However, since it is determined in step S130 that the period from the time point t0 to the time point t1 is an inrush current section, the determination in step S140 (comparison of magnitudes related to the energization amount Ia) is prohibited. Here, the time point t1 corresponds to the “specific time point” at which the inrush current does not affect the forward rotation energization amount Ia.

It is determined that the inrush current section is no longer present at the time point t1 (specific time point) when the specific application time tm (predetermined value) has elapsed from the time point t0. By the determination, it is determined that the influence of the inrush current has been eliminated, and the determination in step S140 is permitted. From the time point t0 to the time point t2, the end member EN and the output member SB are not in contact with each other, and no tension is applied to the parking cable CB. Therefore, the forward rotation energization amount Ia is substantially constant at the value ic. The forward rotation energization amount Ia supplied in a constant state with the value ic is the power transmission mechanism (electric motor MT, speed reducer GS, input member NB, output member SB, from the electric motor MT to the friction member MS. It corresponds to the value caused by the friction (sliding friction) of the parking cable CB, etc.).

From the time point t2, the amount of normal rotation energization Ia begins to increase. This is because after the time point t2, the end member EN and the output member SB come into contact with each other, and the tension of the parking cable CB is gradually increased. At time point t3, the forward rotation current amount Ia reaches the applicable threshold amount ix. At time point t3, “Ia ≧ ix” is satisfied in step S140, the application of the positive sign voltage to the electric motor MT is stopped in step S150, and the forward rotation energization amount Ia is set to “0”. That is, the application control is terminated at the time point t3.

≪Release operation≫
At the time point u0, the parking switch SW is changed from the on state to the off state (that is, a release instruction is given), and the release control is started. At the time point u0, a negative voltage is applied to the electric motor MT by the release control so that the electric motor MT reverses. As a result, energization corresponding to the reverse direction Db of the electric motor MT is started. At the time point u0, the control flag FF (contact determination flag) for determining contact cancellation is set to "0 (contact cancellation undecided)" as an initial value. The electric motor MT is driven in the reverse direction Db, but at least until the time point u1, the end member EN and the output member SB are in contact with each other, and tension is applied to the parking cable CB. By the reverse drive of the electric motor MT, the tension of the parking cable CB is gradually reduced, and the reverse current amount Ib (negative value) gradually increases and approaches "0".

At the time point u1, the reverse energization amount Ib becomes equal to or more than the release amount ik, and the prohibited contact cancellation determination is permitted. At the time point u2, in the braking device DB, the brake lining BL and the brake drum BD (particularly, the inner peripheral surface Mn) do not come into substantially contact with each other. Along with this, at the time point u2, the reverse energization amount Ib becomes substantially constant for the first time, and it is determined that "the reverse energization amount Ib has become constant". However, at the time point u2, the constant state of the reverse energization amount Ib has not yet been continued for the contact determination time th, so that the contact cancellation state is not determined (determined). The constant state of the reverse energization amount Ib is determined by the fact that the energization amount Ib is within a predetermined range ih (a contact determination amount, which is a predetermined constant set in advance). Further, the constant state is determined when the time change amount (time differential value) dIb (release energization change amount) of the reverse energization amount Ib is equal to or less than the contact determination change amount dx (predetermined predetermined constant). You may.

At the time point u3 when the contact determination time th (a predetermined constant set in advance) has elapsed from the time point u2, it is determined (determined) that the contact is canceled, and step S230 is satisfied. Along with this, the contact determination flag FF is switched from "0 (contact cancellation unconfirmed)" to "1 (contact cancellation confirmed)" at time point u3 (confirmation time), and the release duration Tk is calculated (time integration). ) Is started. At the time point u4 when the release threshold time tk (predetermined constant) has elapsed from the time point u3, the application of the negative voltage to the electric motor MT is stopped, and the energization is stopped. That is, the release control is terminated, the reverse energization amount (for example, the current value) Ib is set to "0", and the reverse drive of the electric motor MT is stopped. At this time, the contact determination flag FF is returned from "1" to the initial value "0". With the end of the release control, the movement of the output member SB is stopped. At the end of the release control, there is a gap between the output member SB and the input member NB.

<Processing of application interruption control>
An example of application interruption control processing will be described with reference to the flow chart of FIG. The "application interruption control" is a control when there is a request (interruption request) to interrupt the operation (application operation) of the application control from another controller ECA or ECB during the execution of the above-mentioned application control. For example, the application suspension request is made by transmitting and receiving a control flag (application operation interruption request flag) FL between the controllers via the communication bus BS. The controller ECU and other controllers ECA and ECB share a power supply BT.

In step S310, the request flag for suspending the application operation (simply also referred to as the “application suspension flag”) FL, the forward rotation / reverse rotation amount Ia, Ib (detection value of the current sensor IA), and the supply voltage Va (voltage). Various signals including the detection value of the sensor VA) are read. In step S320, "whether or not the suspension of the application operation is being requested" is determined based on the application suspension flag FL. If the state in which the application interruption flag FL is "1 (with interruption request)" is continued and the application operation is being interrupted by the application control, step S320 is affirmed and the process proceeds to step S370. If the state in which the application interruption flag FL is “0 (no interruption request)” is continued and the interruption of the application operation is not requested, step S320 is denied and the process proceeds to step S330.

In step S330, "whether or not the application suspension request is started" is determined based on the application suspension flag FL. When "FL = 0" in the previous calculation cycle and transition to "FL = 1" in the current calculation cycle, it is determined that the application operation interruption request has started (that is, step S330 is affirmed). The process proceeds to step S340. On the other hand, if the application interruption flag FL remains "0" and there is no interruption request for the application operation, the start of the interruption request is not determined (that is, step S330 is denied) and the process is returned to step S310. Is done. That is, since there is no interruption request, the application operation is continued. The time when step S330 is satisfied (affirmed) is referred to as a "requested time" for suspending the application operation.

In step S340, it is determined whether or not the tightening force Fa becomes excessive when the interruption request is terminated (referred to as “prediction determination”). More specifically, in the prediction determination, "when it is assumed that the operation of the application control is interrupted in response to the interruption request, the tightening force Fa (that is, when the application control operation is performed again to be in the application state" is performed. Whether or not the tightening force Fa) in the state where the applied state is achieved becomes excessive is predicted. In other words, the prediction judgment predicts "whether or not the tightening force Fa is excessive when the request for suspension of the application operation is completed and the parking brake is in the applied state". Is. Here, the tightening force Fa is a force (pushing pressure) exerted by the friction member MS on the rotating member KT.

For example, the deviation (energization amount deviation) hI between the normal rotation energization amount Ia and the applied threshold amount ix at the time when the operation interruption is requested is calculated, and the prediction determination is performed based on this energization amount deviation hI. Specifically, the normal rotation energization amount Ia at the required time point is subtracted from the applicable threshold amount ix, and the energization amount deviation hI is calculated (that is, "hI = ix-Ia"). Then, when the energization amount deviation hI is equal to or greater than the threshold deviation hx, the prediction determination is denied, and "even if the application control is once interrupted and then executed again (that is, even if it is restarted), the tightening force Fa. Will not be excessive. " On the other hand, when the energization amount deviation hI is less than the threshold deviation hx, the prediction judgment is affirmed, and "when the application control is interrupted and then executed again (that is, when it is restarted), the tightening force Fa is determined. It will be excessive. " Here, the threshold deviation hx is a threshold value corresponding to the energization amount deviation hI for making a prediction determination, and is a predetermined value (positive constant) set in advance.

The application control is terminated when the forward rotation energization amount Ia reaches the application threshold amount ix. In a situation where the forward rotation energization amount Ia is considerably smaller than the applicable threshold amount ix and the energization amount deviation hI is large (for example, in the case of “hI ≧ hx”), the operation of the application control has not progressed so much. Therefore, even if the energization is temporarily stopped in this situation and the application control is executed again, the tightening force Fa does not become excessive. On the other hand, in a situation where the forward rotation energization amount Ia is shortly before reaching the applicable threshold amount ix and the energization amount deviation hI is small (for example, in the case of "hI <hx"), the operation of the application control is to some extent. It is progressing. Therefore, if the energization is once stopped in this situation and the application control is executed again, the tightening force Fa may become excessive. From these facts, the prediction of the excessive tightening force Fa is determined based on the energization amount deviation hI.

The threshold deviation hx can be adjusted based on the voltage value Va (for example, the detection value of the voltage sensor VA provided in the drive circuit DR). Specifically, the smaller the voltage value Va, the smaller the threshold deviation hx. This is based on the fact that the smaller the voltage value Va, the more difficult it is for the forward rotation energization amount Ia to increase. By adjusting the threshold deviation hx according to the voltage value Va, the accuracy of predicting the generation of the excessive tightening force Fa can be improved.

The time Te (referred to as “application continuation time”) from the start time of the application control to the time when the operation interruption is requested may be calculated, and the prediction determination may be performed based on the application continuation time Te. Specifically, when the application continuation time Te is less than the continuation threshold time te, the prediction determination is denied, and it is predicted that "the tightening force Fa will not be excessive even if the operation is restarted". On the other hand, when the application continuation time Te is equal to or longer than the continuation threshold time te, the prediction determination is affirmed, and it is predicted that "the tightening force Fa becomes excessive when restarted". Here, the continuation threshold time te is a threshold value corresponding to the application continuation time Te for making a prediction determination, and is a predetermined value (constant) set in advance.

In the application control, the forward rotation energization amount Ia increases with the increase of the time T, and the increase pattern is known. Therefore, in a situation where the application continuation time Te is small (for example, in the case of "Te <te"), the operation of the application control has not progressed so much. Therefore, even if the energization is temporarily stopped in this situation and the application control is executed again, the tightening force Fa does not become excessive. On the other hand, in a situation where the application continuation time Te becomes large (for example, in the case of “Te ≧ te”), the operation of the application control has progressed to some extent. Therefore, if the energization is once stopped in this situation and the application control is executed again, the tightening force Fa may become excessive. From these facts, the prediction of the excessive tightening force Fa described above is determined based on the application continuation time Te.

The continuation threshold time te can be adjusted based on the supply voltage value Va (for example, the detection value of the voltage sensor VA provided in the drive circuit DR). Specifically, the smaller the voltage value Va, the larger the continuation threshold time te. This is based on the fact that the smaller the supply voltage value Va, the more difficult it is for the forward rotation energization amount Ia to increase, and the longer it takes for the forward rotation energization amount Ia to increase. Similarly to the above, the accuracy of predicting the generation of the excessive tightening force Fa can be improved by adjusting the continuation threshold time te according to the voltage value Va.

When step S340 is denied (when the generation of excessive tightening force Fa is not predicted and is also referred to as “predicted denial”), the process proceeds to step S350. On the other hand, when step S340 is affirmed (when an excessive tightening force Fa is predicted to be generated, which is also referred to as “at the time of prediction affirmation”), the process proceeds to step S360.

In step S350, the application of the positive voltage to the electric motor MT is stopped in response to the operation interruption request of the application control, and the supply of the forward rotation energization amount Ia is stopped. That is, if the generation of the excessive tightening force Fa is not predicted, the operation of the application control is temporarily interrupted immediately when the interruption request is started.

In step S360, the application control is continued and its operation is continued. That is, when the generation of an excessive tightening force Fa is predicted, the application control is not interrupted even if the application operation is interrupted, and the supply of the normal rotation energization amount Ia is continued.

In step S370, it is determined whether or not the application control is continued (referred to as "application continuation determination"). If the prediction determination is affirmed and the application control is continued in step S360, step S370 is affirmed and the process proceeds to step S360. On the other hand, when the prediction determination is denied and the application control is interrupted in step S350, step S370 is denied and the process proceeds to step S380.

In step S380, "whether or not the suspension request for the application operation is terminated" is determined based on the application suspension flag FL. When "FL = 1" in the previous calculation cycle and transition to "FL = 0" in the current calculation cycle, the end of the application operation interruption request is determined (that is, step S380 is affirmed). The process proceeds to step S390. On the other hand, when the application suspension flag FL remains "1" and the suspension request is continued, the termination of the suspension request is not determined (that is, step S360 is denied), and the process proceeds to step S350 (that is, step S360 is denied). That is, the energization of the electric motor MT is continued).

In step S390, the application control described with reference to FIGS. 3 and 4 is executed again. The process when the application control operation is executed again is called "reapply process". In other words, the reapply process reactivates the operation by the application control. Since the reapplying process is executed when the generation of an excessive tightening force Fa is not predicted, the tightening force Fa does not become excessive even if the applied state is achieved by the reapplying process.

In the application interruption control, it is predicted whether or not an excessive tightening force Fa is generated when the application control is executed again after the operation is interrupted. If the occurrence is not predicted (when the prediction is negative), the application operation is temporarily interrupted, and the energization of the electric motor MT is immediately stopped. As a result, the decrease in the power supply voltage can be suitably suppressed. Then, in the reactivation of the application control by the reapplication process, the electric motor MT does not need to be reverse-driven in order to reduce the tightening force Fa, so that it is only forward-rotated. Therefore, in the restart, the control (particularly, the control of the electric motor MT) is not complicated.

On the other hand, when the generation of an excessive tightening force Fa is predicted (when the prediction is affirmative), the execution of the application control is continued even if the interruption request is received. If the applied operation is interrupted when the prediction is affirmed, there is a high possibility that an excessive tightening force Fa will be generated after the operation is restarted. Therefore, for example, it is necessary to perform a process in which the tightening force Fa is once reduced and then increased when the operation is restarted. In this process, the forward and reverse rotations of the electric motor MT are repeatedly performed, and the control operation thereof becomes complicated. In addition, since the electric motor MT is once driven in the reverse direction and then driven in the forward direction, it takes time until the application state of the parking brake is achieved.

When the prediction is affirmed, the application operation has progressed considerably, and the application operation is about to end. In other words, even if the application control is continued, the application control is terminated shortly after the time when the prediction determination is affirmed (that is, the time when the interruption request is made). In addition, the situation in which the electric motor MT consumes a large amount of power is the operation in the inrush current section. From the above, even if the application control is continued when the prediction is affirmed, it is unlikely that the power supply voltage will drop. Therefore, as described above, in the application interruption control, when the prediction is affirmative, the application control is continued even if the operation interruption is requested. As a result, the complexity of the control operation is eliminated, and the parking brake can be quickly applied.

<Operation of application interruption control>
The operation of the application interruption control will be described with reference to the time-series diagram (transition diagram of the state quantity with respect to the time T) of FIG. There are two different operations in the application interruption control: (a) an operation when the prediction is affirmative and (b) an operation when the prediction is negative. Here, "at the time of affirmation of prediction" corresponds to the case where the prediction determination in step S340 is affirmed, and "at the time of negative prediction" corresponds to the case where it is denied. In the example, the inrush current section is determined based on the application duration Tj from the start of energization. Further, the prediction determination is made based on the energization amount deviation hI.

First, with reference to FIG. 6A, the operation at the time of affirmative prediction will be described.
At time point v0, the application operation is instructed and the application control is started. By the application control, a positive voltage is applied to the electric motor MT, and the forward rotation drive of the electric motor MT is started. The calculation of the application duration Tj is started from the time v0 when the energization of the electric motor MT is started. Since it is an inrush current section over the specific application time tm from the time point v0 (start time point) to the time point v1 (specific time point), the determination in step S140 (that is, the normal rotation energization amount Ia and the applicable threshold amount ix) Large and small comparison) is prohibited. Therefore, the forward rotation energization amount Ia continues to be supplied regardless of the magnitude of the forward rotation energization amount Ia and the applicable threshold amount ix.

After the time v1 after the inrush current section, the determination in step S140 is permitted, and the normal rotation energization amount Ia and the applicable threshold amount ix are compared for each calculation cycle. At time point v2, the brake lining BL begins to come into contact with the brake drum BD, and the load on the electric motor MT begins to increase. Along with this, an increase in the amount of normal rotation energization Ia is started. At the time point v3, the forward rotation energization amount Ia reaches a value ii that is smaller than the threshold deviation hx by the threshold deviation hx (predetermined constant). Therefore, at time point v3, the deviation hI (carrying amount deviation) between the normal rotation current amount Ia and the applied threshold amount ix coincides with the threshold deviation hx.

At the time point v4, the application interruption flag FL is switched from "0" to "1", and the interruption of the application operation is requested via the communication bus BS. In response to the interruption request, application interruption control is started. At time point v4 (time point of request for interruption of application operation), "At the current time point, if the operation of application control is interrupted in response to the interruption request, if the application operation is performed again after the end of the interruption request, the operation is performed. At the end of the operation, whether or not the tightening force Fa (that is, the final tightening force Fa when the applied state is achieved) becomes excessive or not is determined (see step S340). Specifically, the prediction determination is performed based on the comparison of the magnitude relationship between the deviation (energization amount deviation) hI between the normal rotation energization amount Ia and the applied threshold amount ix at the time point v4 and the threshold deviation hx. Here, the threshold deviation hx is a predetermined value (constant) set in advance.

At the time point v4, since the state of “Ia> iy” is satisfied, the condition of “hI ≧ hx” is satisfied, and the prediction determination in step S340 is affirmed. That is, if the energization of the electric motor MT is interrupted at the time point v4 and the application operation is performed again, it is highly probable that an excessive tightening force Fa will be generated at the end of the application operation. Therefore, after the time point v4, the execution of the application control is continued even though the operation interruption is requested. That is, the forward rotation energization amount Ia continues to be supplied to the electric motor MT. Then, at the time point v5, the condition of "Ia ≧ ix" is satisfied, and the execution of the application control is terminated. With the end of the application control, the voltage application to the electric motor MT is stopped, and the forward rotation energization amount Ia is set to "0".

Next, with reference to FIG. 6B, the operation at the time of negative prediction will be described.
Similar to the time when the prediction is affirmed, the execution of the application control is started at the time point v0, and the forward rotation drive of the electric motor MT is started. At the same time, the application duration Tj is calculated from the time point v0. From the time point v0 to the time point v1 in the inrush current section, the comparison of the normal rotation current amount Ia is prohibited, and the normal rotation current amount Ia is regardless of the magnitude relationship between the normal rotation current amount Ia and the applicable threshold amount ix. It is continuously supplied.

At time point v1, comparison between the forward rotation energization amount Ia and the applicable threshold amount ix (comparison relating to the forward rotation energization amount Ia) is permitted. At the time point v2, the brake lining BL and the brake drum BD come into contact with each other, and the forward rotation energization amount Ia begins to increase. At time point v6, the suspension of the application operation is requested through the application suspension flag FL. At the start time v6 of the interruption request (the time when the application operation is interrupted), the deviation hI (= hx-Ia) between the normal rotation energization amount Ia and the applied threshold amount ix is calculated, and the energization amount deviation hI and the threshold deviation hx. The magnitude relationship with is compared. At the time point v6, since the energization amount deviation hI is equal to or larger than the threshold deviation hx, the prediction determination is denied. That is, it is predicted that even if the energization of the electric motor MT is interrupted at the time point v6, it is unlikely that an excessive tightening force Fa will be generated when the application operation is performed again. Therefore, at the time point v6, the energization to the electric motor MT is temporarily interrupted, and the forward rotation energization amount Ia is set to "0". Along with this, the driving of the electric motor MT is stopped at the time point v6.

From the time point v6 to the time point v7, since "FL = 1" is received in the controller ECU, "Ia = 0" is maintained and the driving of the electric motor MT is stopped. Then, at time point v7, "FL = 1" is switched to "FL = 0", and the request for suspension of the application operation is terminated (affirmation of step S380). From time point v7, the reapply process of step S390 is executed. In the reapply process, the same process as the apply control is repeated again. In other words, after the time point v7, the application control is executed again.

At time point v7, a positive voltage is applied to the electric motor MT again, the forward rotation energization amount Ia is supplied, and the forward rotation drive is started. The calculation of the application duration Tj is started from the time v7 (start time) when the re-energization of the electric motor MT is started. Since the inrush current section is from the start time v7 to the specific time v8, the determination in step S140 is prohibited. From the time point v8 after the inrush current section, the determination in step S140 is permitted. When "Ia <ix" is continued, the voltage application to the electric motor MT is continued. As a result, the forward rotation energization amount Ia increases as the tightening force Fa increases. At the time point v9 when “Ia ≧ ix”, the voltage application to the electric motor MT is stopped, and the process of reapplying operation is completed. Since the power conversion mechanism HN is self-locking, the state in which the parking brake is applied (applied state) is maintained after the time point v9.

<Modification example of application interruption control>
In the above-mentioned application interruption control processing example, the prediction determination in step S340 was performed based on the energization amount deviation hI. Instead of this, the prediction determination may be made based on the application continuation time Te (time from the start time v0). This is based on the fact that since the energization pattern of the forward rotation energization amount Ia is known, the progress of the application control can be estimated according to the length of the application continuation time Te. Hereinafter, a modified example will be briefly described with reference to the description in [] of FIG.

First, the time when the prediction is affirmed will be described with reference to FIG. 6 (a). At time point v0, application control is started, and energization of the forward rotation energization amount Ia is started. At the same time, at time point v0, the calculation of the application continuation time Te is started. At time point v4 (request time point), a request to suspend the application operation is started. At this time, as a prediction determination, "whether or not the application continuation time Te is equal to or longer than the continuation threshold time te" is determined. Here, the continuation threshold time te is a threshold value for prediction determination (corresponding to the application continuation time Te), and is a predetermined value (constant) set in advance. In the example, at the request time v4 for suspending the application operation, “Te ≧ te”, so that the prediction determination is affirmed. Therefore, even if there is a request for interruption, the application operation is not interrupted.

Next, the time when the prediction is negative will be described with reference to FIG. 6 (b). At the time point v0, the application control is started, and the calculation of the application continuation time Te is started. At time point v6 (request time point), a request to suspend the application operation is started. Since the application continuation time Te is less than the continuation threshold time te at the request time v6 of the application operation interruption, the prediction judgment of "whether or not the application continuation time Te is equal to or more than the continuation threshold time te" is denied. .. Therefore, the application operation is interrupted in response to the interruption request. After that, the reapply process is started at the time v7 when the suspension request is completed.

<Processing example of release interruption control>
An example of the processing of the release interruption control will be described with reference to the flow chart of FIG. 7. The "release interruption control" is a control when there is a request (interruption request) to interrupt the operation (release operation) of the release control from another controller ECA or ECB during the execution of the above-mentioned release control. For example, the release operation interruption request is made by transmitting and receiving a control flag (release operation interruption request flag) FK between the controllers via the communication bus BS. The controller ECU and other controllers ECA and ECB share a power supply BT.

In step S410, a request flag for interrupting the release operation (simply also referred to as a “release interruption flag”) FK, a contact determination flag FF, and forward / reverse current energization amounts Ia and Ib (detection values of the energization amount sensor IA). Various signals including are read. In step S420, it is determined "whether or not the cancellation operation is being interrupted" based on the release interruption flag FK. If the state in which the release interruption flag FK is "1 (with interruption request)" is continued and the operation (release operation) interruption request by the release control is in progress, step S420 is affirmed and the process proceeds to step S470. Will be. If the state in which the release interruption flag FK is "0 (no interruption request)" is continued and the release operation interruption is not requested, step S420 is denied and the process proceeds to step S430.

In step S430, "whether or not the release operation interruption request is started" is determined based on the release interruption flag FK. When "FK = 0" in the previous calculation cycle and transition to "FK = 1" in the current calculation cycle, it is determined that the release operation suspension request has started (that is, step S430 is affirmed). The process proceeds to step S440. On the other hand, if the release interruption flag FK remains "0" and there is no interruption request for the release operation, the interruption request start is not determined (that is, step S430 is denied), and the process is returned to step S410. , The release operation is continued. The time when step S430 is satisfied (affirmed) is referred to as a "requested time" for suspending the release operation.

In step S440, "whether or not the contact is canceled (that is, whether the contact is canceled or not)" is determined based on the contact determination flag FF. When "FF = 0" and the contact cancellation is undecided at the time when the interruption request is started (in other words, when the interruption request is started before the contact cancellation state is determined), Step S440 is denied and processing proceeds to step S450. On the other hand, when "FF = 1" and the contact cancellation is confirmed at the time when the interruption request is started (in other words, when the interruption request is started after the contact cancellation state is confirmed), Step S440 is affirmed and processing proceeds to step S460.

In step S450, the application of the negative voltage to the electric motor MT is stopped in response to the operation interruption request of the release control, and the supply of the reverse energization amount Ib is stopped. That is, if the contact cancellation state is not determined at the time when the interruption request is started, the operation of the release control is temporarily interrupted immediately at the time when the release operation interruption is requested. At this time, the release duration Tk is reset and returned to "0".

In step S460, the release control is continued and its operation is continued. That is, when the contact cancellation state is determined at the time when the interruption request is started, the release control is not interrupted and the supply of the reverse energization amount Ib is continued even if the release operation is interrupted.

In step S470, it is determined whether or not the release control is continued (referred to as "release continuation determination"). When the contact cancellation state is confirmed and the release control is continued in step S460, step S470 is affirmed and the process proceeds to step S460. On the other hand, when the contact cancellation state is undecided and the release control is interrupted in step S450, step S470 is denied and the process proceeds to step S480.

In step S480, "whether or not the cancellation request for interruption of the release operation is terminated" is determined based on the release interruption flag FK. When "FK = 1" in the previous calculation cycle and transition to "FK = 0" in the current calculation cycle, the end of the cancellation request is determined (that is, step S480 is affirmed). The process proceeds to step S490. On the other hand, when the release interruption flag FK remains "1" and the interruption request is continued, the end of the interruption request is not determined (that is, step S460 is denied), and the process proceeds to step S450. The energization of the electric motor MT is continued.

In step S490, the release control described with reference to FIGS. 3 and 4 is executed again. The process when the release control operation is executed again is called "re-release process". In other words, the re-release process reactivates the operation by the release control. The re-release process is executed when the contact release state has not been determined. At this time, since the release process has not progressed so much, excessive displacement of the member cannot be generated by the re-release process.

In the release interruption control, it is determined whether or not the contact is released at the start of the operation interruption request. If it is determined that the contact cancellation state has not been achieved yet (when the contact cancellation is uncertain), the release operation is temporarily interrupted, and the energization of the electric motor MT is immediately stopped. As a result, the decrease in the power supply voltage can be suitably suppressed. Then, in the reactivation of the release control by the re-release process, the electric motor MT does not need to be driven in the forward direction in order to bring the brake lining BL and the brake drum BD into contact with each other again, so that the electric motor MT is only driven in the reverse direction. Therefore, in the restart, the control (particularly, the control of the electric motor MT) is not complicated.

On the other hand, when the contact cancellation state has already been determined at the start of the operation interruption request (that is, when the contact cancellation is confirmed), the execution of the release control is continued even if the interruption request is received. This is because if the release operation is interrupted when the contact release is confirmed, there is a high possibility that excessive displacement of the member (output member SB or the like) will occur after the operation is restarted. Therefore, for example, it is necessary to process that the output member SB or the like is once moved in the forward direction Ha and then moved in the backward direction Hb when the operation is restarted. In this process, the forward and reverse rotations of the electric motor MT are repeatedly performed, and the control operation thereof becomes complicated. In addition, since the electric motor MT is driven in the forward rotation and then in the reverse rotation, it takes time for the parking brake to be released.

When the release operation is confirmed, the release operation has progressed considerably, and the release operation is about to end. In other words, even if the release control is continued, the release control is terminated shortly after the interruption request is made. In addition, in the state where the release operation is confirmed, the power consumption of the electric motor MT is only used for the sliding friction of the power transmission member. From the above, even if the release control is continued when the pre-release operation is confirmed, it is unlikely that the power supply voltage will drop. Therefore, as described above, in the release interruption control, when the release operation is confirmed, the release control is continued even if the operation interruption is requested. As a result, the complexity of the control operation can be eliminated, and the parking brake can be quickly released.

<Operation of release interruption control>
The operation of the release interruption control will be described with reference to the time-series diagram (transition diagram of the state quantity with respect to the time T) of FIG. There are two different operations in the release interruption control: (a) an operation when the contact cancellation is confirmed and (b) an operation when the contact cancellation is not confirmed. Here, "when contact cancellation is confirmed" corresponds to the case where the determination in step S440 is affirmed, and "when contact cancellation is not confirmed" corresponds to the case where it is denied. In the example, the release interruption flag FK is shown by a solid line, and the contact determination flag FF is shown by a broken line. The above-mentioned permission determination of "Ib ≧ ik" may be omitted.

First, with reference to FIG. 8A, the operation at the time of confirming the contact cancellation (that is, when the contact cancellation state has already been determined at the start time of the interruption request) will be described.
At the time point w0, the release operation is instructed and the release control is started. By the release control, a negative voltage is applied to the electric motor MT, and the reverse drive of the electric motor MT is started. Since the friction member MS and the rotating member KT are in contact with each other at least until the time point w2, a load is generated on the electric motor MT. Since the load of the electric motor MT is gradually reduced by the reverse drive of the electric motor MT, the reverse current energization amount Ib (negative value) gradually increases and approaches "0". At the time point w1, the permission condition of “Ib ≧ ik” is satisfied, and the execution of the contact cancellation determination in step S230 is permitted.

At the time point w2, the friction member MS and the rotating member KT do not come into substantially contact with each other. Along with this, for the first time, it is determined that "the amount of reverse energization Ib has become constant". However, at the time point w2, the constant state of the reverse energization amount Ib has not yet been continued for the contact determination time th, so that the contact cancellation state is not determined. That is, at the time point w2, the contact cancellation is still undecided. The contact cancellation state is determined at the time point w3 when the contact determination time th has elapsed from the time point w2. That is, at the confirmation time w3, the transition from the "contact cancellation unconfirmed state" to the "contact cancellation confirmed state". Along with this, at the time point w3, the contact determination flag FF (indicated by the broken line) is switched from "0 (contact cancellation unconfirmed)" to "1 (contact cancellation confirmed)". Further, at the time point w3, the calculation of the release duration Tk is started.

At the time point w4, the release interruption flag FK is switched from "0" to "1", and the interruption of the release operation is requested via the communication bus BS. In response to the interruption request, the release interruption control is started. At the time point w4 (request time point), the determination of "whether or not the contact is canceled" is performed based on the contact determination flag FF (see step S440). Since the contact determination flag FF has already been switched to "1" at the time point w3 before the start time of the interruption request, the determination in step S440 is affirmed. Therefore, after the time point w4, the execution of the release control is continued even though the operation interruption is requested. That is, the reverse energization amount Ib continues to be supplied to the electric motor MT. Then, at the time point w5, the condition of "Tk ≧ tk" is satisfied, and the execution of the release control is terminated. With the end of the release control, the application of the negative voltage to the electric motor MT is stopped, and the reverse energization amount Ib is set to "0".

Next, with reference to FIG. 8B, the operation when the contact cancellation is undetermined (that is, when the contact cancellation state has not yet been determined at the start of the interruption request) will be described.
Similar to the time when the contact cancellation is confirmed, the execution of the release control is started at the time point w0, and the reverse drive of the electric motor MT is started. At the time point w1, the contact cancellation determination in step S230 is permitted. At time point w6, the cancellation operation is requested to be interrupted through the release interruption flag FK. At the time point w6 (request time point), the contact cancellation state has not yet been determined, and the contact cancellation state is undecided. Therefore, at the time point w6, the energization to the electric motor MT is temporarily interrupted, and the reverse energization amount Ib is set to "0". Along with this, the driving of the electric motor MT is stopped at the time point w6.

From the time point w6 to the time point w7, since "FK = 1" is received in the controller ECU, "Ib = 0" is maintained and the driving of the electric motor MT is stopped. Then, at the time point w7, the release interruption flag FK is switched from "1" to "0", and the interruption request for the release operation is terminated (affirmation in step S480). From the time point w7, the re-release process of step S490 is executed. In the re-release process, the same process as the release control is repeated again. In other words, after the time point w7, the release control is executed again.

At the time point w7, a negative voltage is applied to the electric motor MT again, the reverse energization amount Ib is supplied, and the reverse drive is started. At the time point w8, “Ib ≧ ik” is satisfied, and the contact cancellation determination in step S230 is permitted. At the time point w9, the friction member MS and the rotating member KT do not come into substantially contact with each other. At the time point w10, the contact cancellation state is determined, and the calculation of the release duration Tk is started. At the time point w11, since the release duration Tk reaches the release threshold time tk, the voltage application to the electric motor MT is stopped, and the process of the re-release operation is completed. After the time point w11, the released state of the parking brake is maintained.

<Summary of each embodiment and actions / effects>
The embodiments of the electric parking brake device EP are summarized below.
The electric parking brake device EP drives the electric motor MT in the forward rotation direction Da to generate a tightening force Fa between the rotating member KT provided on the wheel and the friction member MS to apply the parking brake and apply electricity. The motor MT is driven in the reverse direction Db to release the parking brake. The electric parking brake device EP is provided with a controller ECU that controls the electric motor MT.

When the parking brake is applied, the controller ECU supplies the forward rotation current amount Ia corresponding to the forward rotation direction Da to the electric motor MT, and starts supplying the forward rotation current amount Ia to the electric motor MT. Until a specific point in time when the influence of the inrush current disappears, the normal rotation energization amount Ia is supplied without comparing the normal rotation energization amount Ia and the applicable threshold amount ix, and after the specific point point, the normal rotation energization amount Ia is used. Comparison with the applicable threshold amount ix is performed, and if the normal rotation current amount Ia is less than the applicable threshold amount ix, the normal rotation current amount Ia is supplied, and if the normal rotation current amount Ia is the applicable threshold amount ix or more. The forward rotation current amount Ia is stopped. The control is an application control. Further, in the controller ECU, when the interruption is requested during the execution of the application control, "when the interruption request related to the application control is terminated, the tightening force Fa (for example, the time when the application state is achieved) is achieved. Whether or not the tightening force Fa) becomes excessive is determined. Then, if the prediction determination is affirmed, the application control is continued contrary to the interruption request. On the other hand, if the prediction determination is denied, the application control is interrupted in response to the interruption request.

If there is an operation interruption request in the middle of the application operation, it is determined as a prediction determination "whether or not an excessive tightening force Fa is generated when the application control is executed again after the operation is interrupted". If the prediction determination is denied, the application operation is interrupted, so that the decrease in the power supply voltage is suitably suppressed and an excessive tightening force Fa is not generated. Further, in the restart after the interruption of the application process, the electric motor MT is driven only in the forward rotation direction Da, so that the complexity of control (particularly, control of the electric motor MT) is avoided. On the other hand, if the prediction determination is affirmed, the execution of the application control is continued even if there is a suspension request. As a result, the complexity of motor control when the application operation is restarted is eliminated, and the parking brake is quickly put into the application state.

For example, in the controller ECU, the prediction determination can be made based on the deviation hI (the energization amount deviation) between the normal rotation energization amount Ia and the applicable threshold amount ix at the time when the operation interruption is requested. Specifically, the energization amount deviation hI is calculated, and the prediction judgment is denied when the energization amount deviation hI is equal to or more than the threshold deviation hx, and the prediction is made when the energization amount deviation hI is less than the threshold deviation hx. The judgment is affirmed. Since the application control is terminated when the forward rotation energization amount Ia reaches the applicable threshold amount ix, it is possible to predict the occurrence of an excessive tightening force Fa based on the energization amount deviation hI. In the case of "hI ≧ hx", the operation of the application control has not progressed so much, and the possibility of the generation of the excessive tightening force Fa is low, so that the prediction determination is denied. In the case of "hI <hx", the operation of the application control has progressed to some extent, and there is a high possibility that an excessive tightening force Fa will be generated, so that the prediction determination is affirmed. It should be noted that the smaller the supply voltage value Va, the smaller the threshold deviation hx can be adjusted based on the voltage value Va. The adjustment can improve the accuracy of the prediction determination.

Further, in the controller ECU, the prediction determination is performed based on the application continuation time Te, which is the time from the start time of the application control (that is, the supply start time of the forward rotation current amount Ia) to the time when the operation interruption is requested. May be good. Specifically, the application continuation time Te is calculated, and if the application continuation time Te is less than the continuation threshold time te, the prediction judgment is denied, and if the application continuation time Te is greater than or equal to the continuation threshold time te. Is affirmed. In the application control, the increase pattern of the forward rotation energization amount Ia with respect to the time T is known. Therefore, it is possible to predict the occurrence of an excessive tightening force Fa based on the application continuation time Te. In the case of "Te <te", the operation of the application control has not progressed so much, and the possibility of the generation of the excessive tightening force Fa is low, so the prediction determination is denied. In the case of "Te ≧ te", the operation of the application control has progressed to some extent, and there is a high possibility that an excessive tightening force Fa will be generated, so that the prediction determination is affirmed. Based on the supply voltage value Va, the smaller the voltage value Va, the larger the continuation threshold time te can be adjusted. The adjustment can improve the accuracy of the prediction determination.

In the electric parking brake device EP, the controller ECU determines the contact cancellation state in which the rotating member KT and the friction member MS do not come into contact with each other when the parking brake is released. When the tk is reached, the drive of the electric motor MT is stopped. The control is a release control. Further, in the controller ECU, when the cancellation control is requested to be interrupted after the determination point, the release control is continued contrary to the interruption request. On the other hand, if the release control is requested to be interrupted before the determination point, the release control is interrupted in response to the interruption request.

When there is an operation interruption request in the middle of the release operation, it is determined as "whether or not the contact state between the friction member MS and the rotating member KT is canceled" as the contact cancellation determination. When the contact cancellation state has not been determined yet (when the contact cancellation is not confirmed), the energization of the electric motor MT is immediately stopped, so that the decrease in the power supply voltage is suitably suppressed and the excessive displacement of the constituent members is suppressed. Is avoided. Further, in the restart after the interruption of the release process, the electric motor MT is driven only in the reverse direction Db, so that the complexity of control (particularly, control of the electric motor MT) is avoided. On the other hand, when the contact cancellation state has already been determined (when the contact cancellation is confirmed), the execution of the release control is continued even if there is an interruption request. As a result, the complexity of motor control when the release operation is restarted is eliminated, and the parking brake is quickly released.

<Other embodiments>
Hereinafter, other embodiments of the electric parking brake device EP will be described. In other embodiments, the same effects as described above (reduction of complexity of control and rapid operation) are obtained.

In the above embodiment, the operation of the electric parking brake device EP according to the operation of the parking switch SW (application control according to the application instruction / release control according to the release instruction) has been described. The application / release instruction of the electric parking brake device EP may be automatically given instead of the operation of the parking switch SW. The situation in which the electric parking brake device EP is automatically operated is called "automatic mode". In the automatic mode, for example, when the vehicle stops, the electric parking brake device EP automatically gives an application instruction, and a parking braking force Fp is generated (assigned). Further, when the acceleration operation member (accelerator pedal or the like) is operated by the driver and the operation amount Ap increases from "0 (zero)", the electric parking brake device EP automatically gives a release instruction. The automatic mode is executed by the vehicle body speed Vx and the acceleration operation amount Ap acquired by the controller ECU via the communication bus BS.

In a vehicle equipped with an automatic braking device, the automatic mode of the electric parking brake device EP may be executed without any operation by the driver. For example, the vehicle body speed Vx is automatically adjusted by detecting a preceding vehicle so as to support driving in a traffic jam or the like. Then, when the preceding vehicle stops, the vehicle automatically stops while maintaining the inter-vehicle distance, an application instruction is automatically given, and the electric parking brake device EP is applied and operated. After that, when the preceding vehicle starts, a release instruction is automatically given, the electric parking brake device EP is released, and the vehicle body speed Vx of the own vehicle is adjusted so as to follow the preceding vehicle.

In the above embodiment, a drum type brake is adopted as the braking device DB. Instead of this, a disc type brake may be adopted as the braking device DB. In the disc type brake, a brake pad is adopted as the friction member MS, and a brake disc is adopted as the rotating member KT.

EP ... Electric parking brake device, BT ... Storage battery (power supply), AL ... Generator (power supply), ECU ... Controller (for electric parking brake device), ECA, ECB ... Other controllers, BS ... Communication bus, FL ... Application suspension Flag (control flag for interruption request of applied operation), FK ... release interruption flag (control flag for interruption request of release operation), FF ... release determination flag (control flag indicating contact cancellation state), SW ... parking switch, DB ... Braking device, KT ... Rotating member, BD ... Brake drum (an example of rotating member KT), MS ... Friction member, BL ... Brake lining (an example of friction member MS), CB ... Parking cable, DN ... Electric actuator, MT ... Electric motor, GS ... Reducer, NB ... Input member, SB ... Output member, MP ... Microprocessor, DR ... Drive circuit, IA ... Energization amount sensor (for example, current sensor), VA ... Voltage sensor, Ia ... Forward rotation Energization amount (energization amount corresponding to forward rotation direction Da), Ib ... Reverse energization amount (energization amount corresponding to reverse rotation direction Db), Va ... Voltage value (supply voltage value to electric motor MT), ix ... Applicable threshold Amount (threshold for end of application operation), tk ... Release threshold time (threshold for end of release operation), tm ... Specific application time.

Claims (4)

An electric parking brake device for a vehicle that drives an electric motor in the forward rotation direction to generate a tightening force between a rotating member and a friction member provided on the wheels of the vehicle to apply a parking brake.
A controller for controlling the electric motor is provided.
The controller
When the parking brake is applied, the amount of normal rotation energization corresponding to the normal rotation direction is supplied to the electric motor, and the influence of the inrush current of the electric motor is exerted from the start point when the supply of the normal rotation energization amount is started. The normal rotation energization amount is supplied until a specific point in time when the normal rotation disappears, and after the specific time point, the normal rotation energization amount is supplied when the normal rotation energization amount is less than the applicable threshold amount, and the normal rotation energization amount is supplied. When the amount is equal to or greater than the applicable threshold amount, the application control for stopping the normal rotation energization amount is executed, and the application control is executed.
The controller
When the interruption of the application control is requested during the execution of the application control, it is predicted and determined whether or not the tightening force becomes excessive when the request is terminated.
If the prediction determination is affirmed, the application control is continued and the application control is continued.
An electric parking brake device for a vehicle that interrupts the applied control when the prediction determination is denied. In the electric parking brake device of the vehicle according to claim 1,
The controller
The deviation between the normal rotation energization amount and the applicable threshold amount at the time when the interruption is requested is calculated.
If the deviation is greater than or equal to the threshold deviation, the prediction determination is denied.
An electric parking brake device for a vehicle that affirms the prediction determination when the deviation is less than the threshold deviation. In the electric parking brake device of the vehicle according to claim 1,
The controller
The application continuation time, which is the time from the start time to the time when the interruption is requested, is calculated.
If the application continuation time is less than the continuation threshold time, the prediction determination is denied.
An electric parking brake device for a vehicle that affirms the prediction determination when the application continuation time is equal to or longer than the continuation threshold time. An electric parking brake device for a vehicle that drives an electric motor in the reverse direction to release the parking brake.
A controller for controlling the electric motor is provided.
The controller
When the parking brake is released, the drive of the electric motor is stopped when the release duration from the confirmation time for determining the contact cancellation state in which the rotating member and the friction member are no longer in contact reaches the release threshold time. Execute release control and
The controller
If the release control is requested to be interrupted after the confirmation point, the release control is continued.
An electric parking brake device for a vehicle that interrupts the release control when the release control is requested to be interrupted before the determination point.

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