ELECTRIC PARKING BRAKE SYSTEM AND METHOD FOR CONTROLLING THE ELECTRIC PARKING BRAKE SYSTEM
First Claim
1. An electric parking brake system, comprising:
- a brake that includes a rotating body which has a friction face and which rotates together with a wheel, a friction member which is fitted to a non-rotating body so as to be movable relative to the non-rotating body and which suppresses a rotation of the rotating body when being pushed against the friction face of the rotating body, and a pushing mechanism that pushes the friction member against the friction face of the rotating body;
an electric motor;
a motion conversion mechanism that converts a rotation of a rotating shaft of the electric motor into a linear motion of an output member of the motion conversion mechanism;
a connection unit that is connected at one end to the output member of the motion conversion mechanism, and that is connected at the other end to the pushing mechanism;
a maintaining mechanism that maintains a friction member pushing force that is a force with which the friction member is pushed against the friction face in the brake, when electric current is not supplied to the electric motor; and
a pushing force control unit that controls the electric motor such that the friction member pushing force in the brake approaches a target value that is set based on a moving force applied to a vehicle,wherein the pushing force control unit includes a tentative target value setting unit that sets a tentative target value of the friction member pushing force each time a predetermined condition is satisfied while the brake is on; and
a final target value setting unit that sets a target value in a current routine to a target value in an immediately preceding routine when the tentative target value in the current routine, which is set by the tentative target value setting unit, is equal to or smaller than the target value in the immediately preceding routine, and that sets the target value in the current routine to the tentative target value in the current routine, which is set by the tentative target value setting unit, when the tentative target value in the current routine is larger than the target value in the immediately preceding routine.
1 Assignment
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Accused Products
Abstract
During the standstill state maintenance control executed by an electric parking brake system, the moving force-based target tension Frefb is determined based on the inclination angle of a vehicle and the shift position each time the predetermined program is executed, and the tentative target tension Fref(n) in the current routine is set to a smaller value from among the moving force-based target tension Frefb and the maximum value Fmax. The control target tension Fref(n)* is set to a larger value from among the control target tension (the final target tension) Fref(n−1)* in the immediately preceding routine and the tentative target value Fref(n). Even if the tentative target tension Fref(n) is smaller than the control target tension Fref(n−1)*, the control target value Fref(n)* is not set to a value smaller than the control target tension Fref(n−1)*.
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Citations
14 Claims
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1. An electric parking brake system, comprising:
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a brake that includes a rotating body which has a friction face and which rotates together with a wheel, a friction member which is fitted to a non-rotating body so as to be movable relative to the non-rotating body and which suppresses a rotation of the rotating body when being pushed against the friction face of the rotating body, and a pushing mechanism that pushes the friction member against the friction face of the rotating body; an electric motor; a motion conversion mechanism that converts a rotation of a rotating shaft of the electric motor into a linear motion of an output member of the motion conversion mechanism; a connection unit that is connected at one end to the output member of the motion conversion mechanism, and that is connected at the other end to the pushing mechanism; a maintaining mechanism that maintains a friction member pushing force that is a force with which the friction member is pushed against the friction face in the brake, when electric current is not supplied to the electric motor; and a pushing force control unit that controls the electric motor such that the friction member pushing force in the brake approaches a target value that is set based on a moving force applied to a vehicle, wherein the pushing force control unit includes a tentative target value setting unit that sets a tentative target value of the friction member pushing force each time a predetermined condition is satisfied while the brake is on; and
a final target value setting unit that sets a target value in a current routine to a target value in an immediately preceding routine when the tentative target value in the current routine, which is set by the tentative target value setting unit, is equal to or smaller than the target value in the immediately preceding routine, and that sets the target value in the current routine to the tentative target value in the current routine, which is set by the tentative target value setting unit, when the tentative target value in the current routine is larger than the target value in the immediately preceding routine. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for controlling an electric parking brake system, comprising:
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setting a tentative target value of a friction member pushing force in a brake, which is set based on a moving force applied to a vehicle, each time a predetermined condition is satisfied while the brake is on, the brake including;
a rotating body that has a friction face and that rotates together with a wheel;
a friction member that is fitted to a non-rotating body so as to be movable relative to the non-rotating body and that suppresses a rotation of the rotating body when being pushed against the friction face of the rotating body; and
a pushing mechanism that pushes the friction member against the friction face of the rotating body;setting a target value in a current routine to a target value in an immediately preceding routine when the set tentative target value in the current routine is equal to or smaller than the target value in the immediately preceding routine; and setting the target value in the current routine to the tentative target value in the current routine when the tentative target value in the current routine is larger than the target value in the immediately preceding routine. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification