JP7431939B2 - Electric parking brake device for vehicles - Google Patents

Description

The present invention provides a parking brake lever that is rotatable between an activated position for obtaining a parking brake state and a non-operative position for releasing the parking brake state, and is elastically biased toward the non-operative position; The parking brake is switchable between a forward rotation state in which power is exerted to move the parking brake lever from the non-operation position to the operation position and a reverse rotation state in which the parking brake lever is returned from the operation position to the non-operation position. an electric actuator that has an electric motor connected to a lever and is capable of applying a load to the electric motor after a state in which the load on the electric motor becomes no load when the electric motor is reversed; The present invention relates to an electric parking brake device for a vehicle, comprising: a control unit that controls the operation of the electric motor; and current detection means that detects the current flowing to the electric motor.

The parking brake lever is moved to the operating position by the operation of the electric actuator to obtain the parking brake state, and the parking brake force is released in accordance with the operation of the electric actuator to move the parking brake lever to the non-operating position. An electric parking brake device for a vehicle is known from Patent Document 1.

Japanese Patent No. 6176456

By the way, in an electric parking brake system for a vehicle, when the parking brake is released, the load applied to the electric motor of the electric actuator becomes so small that it can no longer be distinguished from the no-load current, and the multiple members that make up the electric actuator return too much, resulting in a locked state. There is a possibility of falling into. For this reason, in the device disclosed in Patent Document 1, by applying a spring load to a linear motion member that constitutes a part of the electric actuator, the slope of the increasing current flowing to the electric motor is detected, and the slope is Excessive return is prevented from occurring in response to a predetermined value being exceeded. However, the slope of the current value also fluctuates due to noise caused by various electrical factors and mechanical factors (for example, external voltage fluctuations, motor internal structure, etc.), and the method disclosed in Patent Document 1 above does not allow for such fluctuations. Due to this, there is a possibility that the electric motor stops operating earlier than expected.

The present invention has been made in view of the above circumstances, and provides an electric parking brake device for a vehicle that can quickly and accurately stop the operation of an electric motor after the no-load current state has passed when releasing the parking brake state. The purpose is to provide

In order to achieve the above object, the present invention enables rotation between an activated position for obtaining a parking brake condition and a non-activated position for releasing the parking brake condition, and also enables rotation toward the non-activated position side. a forward rotation state in which the parking brake lever is exerted with power to move the parking brake lever from the non-operating position to the operating position; and a reverse rotation state in which the parking brake lever is returned from the operating position to the non-operating position. It has an electric motor that is connected to the parking brake lever so that its state can be changed, and it is possible to apply a load to the electric motor after a state in which the load on the electric motor becomes no load when the electric motor is reversed. an electric actuator; a control unit that controls operation of the electric motor; and current detection means that detects current flowing to the electric motor; includes a slope calculating means for calculating the slope of the current value detected by the current detecting means; and a slope calculating means for calculating the slope of the current value detected by the current detecting means, and a slope calculating means for calculating the slope of the current value detected by the current detecting means; Current stabilization determining means for determining that the energizing current has stabilized after the start of energization based on a current value detected by the current detecting means; and a setting after the current stabilizing determining means determines that the energizing current has stabilized. storage means for storing the slope of the current value calculated by the slope calculation means within a time; and storage means for storing the slope of the current value on the increasing side other than the slope of the current value stored in the storage means after the elapse of the set time. A first feature of the present invention is that it includes motor stop determination means for stopping the operation of the electric motor based on the calculation by the slope calculation means.

Further, in addition to the configuration of the first feature, the present invention provides that the motor stop determination means determines whether the slope of the current value on the increasing side other than the slope of the current value stored in the storage means after the elapse of the set time has elapsed. A second feature is that in a state where the detection continues, it is determined whether or not to stop the operation of the electric motor based on the current value detected by the current detection means.

According to the first feature of the present invention, when the electric motor is loaded after the no-load current state ends, an increase in the current value other than the slope of the current value caused by noise in the no-load current state increases. Since the operation of the electric motor is stopped according to the side tilt detected, the slope of the current value caused by noise caused by various electrical and mechanical factors is eliminated, and the current value can be quickly and easily removed after the no-load current state has passed. It is possible to accurately stop the operation of the electric motor.

According to the second feature of the present invention, even if it is not possible to determine whether the electric motor should stop operating based on the slope of the current value, the operation of the electric motor can be reliably stopped based on the current value.

FIG. 1 is a front view of the drum brake device. (First embodiment) FIG. 2 is a rear view of the drum brake. (First embodiment) FIG. 3 is a longitudinal sectional view of the electric actuator. (First embodiment) FIG. 4 is a block diagram showing the configuration of the control unit. (First embodiment) FIG. 5 is a flowchart showing part of the control procedure. (First embodiment) FIG. 6 is a flowchart showing a control procedure following the control procedure of FIG. (First embodiment) FIG. 7 is a flowchart showing a control procedure following the control procedure of FIG. (First embodiment) FIG. 8 is a diagram showing an example of a change in the applied current over time when the electric motor is reversed. (First embodiment)

34...Parking brake lever 38...Electric actuator 41...Electric motor 84...Current detection means 87...Slope calculation means 88...Current stabilization judgment means 89...Storage means 90. ...Motor stop judgment means C...Control unit

Embodiments of the present invention will be described with reference to the accompanying FIGS. 1 to 8.

First embodiment

First, in FIG. 1, a drum brake B is provided on a wheel of a four-wheeled vehicle, such as a left rear wheel. A back plate 13, first and second brake shoes 15, 16 disposed within the back plate 13 so as to be able to come into sliding contact with the inner periphery of the brake drum 14 rotating together with the left rear wheel; Between the wheel cylinder 17, which is fixed to the back plate 13 so that the second brake shoes 15, 16 exert an expanding force, and the first and second brake shoes 15, 16 and the brake drum 14. It includes an automatic braking gap adjustment means (so-called auto adjuster) 18 that automatically adjusts the gap, and a return spring 19 provided between the first and second brake shoes 15 and 16.

The first and second brake shoes 15, 16 include first and second webs 15a, 16a formed in an arcuate flat plate shape along the inner periphery of the brake drum 14, and the first and second webs 15a, 16a. First and second rims 15b, 16b are arranged in a row perpendicularly to the outer peripheries of the second webs 15a, 16a, and first and second rims 15b, 16b are attached to the outer peripheries of the first and second rims 15b, 16b. It consists of second linings 15c and 16c.

An anchor plate 21, which serves as a fulcrum when the first and second brake shoes 15, 16 expand and contract, is attached to the back plate 13 at one end of the first and second webs 15a, 16a (in this embodiment). (lower end) is rotatably supported. Further, the wheel cylinder 17 is operated by the output hydraulic pressure of a master cylinder (not shown) operated by a brake pedal, and expands the first and second brake shoes 15 and 16 using the anchor plate 21 as a fulcrum. A pair of pistons 20 of this wheel cylinder 17 are fixed to the back plate 13 between the other ends of the first and second brake shoes 15 and 16 so as to exert a driving force toward the side. The outer end portion is arranged to face the other end portions (in this embodiment, the upper end portions) of the first and second webs 15a, 16a.

A coil spring 22 is provided between the one ends of the first and second webs 15a, 16a to bias the one ends of the first and second webs 15a, 16a toward the anchor plate 21. A pair of return springs 19 are provided between the other ends of the first and second webs 15a, 16a to bias the first and second brake shoes 15, 16 in the direction of contraction.

The braking gap automatic adjustment means 18 is provided between the first and second webs 15a and 16a of the first and second brake shoes 15 and 16, and is a retracted position limiter that can be extended by rotation of the adjustment gear 23. It has a strut 24 and a feed pawl 25a that engages with the adjustment gear 23, and is rotatable on the second web 16a of the second brake shoe 16 of the first and second brake shoes 15, 16. It is composed of a supported adjustment lever 25, and an adjustment spring 26 that urges the adjustment lever 25 to rotate in a direction that causes the adjustment gear 23 to rotate in a direction that extends the contraction position regulating strut 24.

The contracted position regulating strut 24 regulates the contracted positions of the first and second brake shoes 15 and 16, and is provided in the first brake shoe 15 of the first and second brake shoes 15 and 16. A first rod 27 having a first engagement connecting portion 27a that engages near the other end of the first web 15a, and a second web 16a of the second brake shoe 16 that engages near the other end. A second rod 28 is disposed coaxially with the first rod 27 and has a second engagement connecting portion 28a that engages with the second rod 28; The adjustment gear 23 is disposed between the first and second rods 27 and 28 and has an adjustment bolt 29 whose other end is threaded coaxially with the second rod 28 . is formed.

A first locking recess 30 for engaging the first engagement connecting portion 27a is provided on the side edge of the first web 15a facing the axle 11 near the other end, and the second web 16a A second locking recess 31 is provided on a side edge facing the axle 11 near the other end of the wheel, and the second locking recess 31 is engaged with the second engaging connecting portion 28a.

An adjustment lever 25 having a feed pawl 25a that engages with the adjustment gear 23 is rotatably supported by the second web 16a via a support shaft 32, and is arranged between the second web 16a and the adjustment lever 25. The adjustment spring 26 is provided at. Moreover, the spring force of the adjustment spring 26 is set smaller than the spring force of the return spring 19.

According to such automatic braking gap adjustment means 18, when the first and second brake shoes 15, 16 are expanded by the operation of the wheel cylinder 17, the wear of the first and second linings 15c, 16c is reduced. If the expansion exceeds a certain value due to Accordingly, the effective length of the contraction position regulating strut 24 is corrected to increase.

By the way, this drum brake B is equipped with a parking brake lever 34 that can generate a parking brake force in accordance with its operation, and this parking brake lever 34 is connected to a portion of the first web 15a of the first brake shoe 15. The first web 15a is arranged so as to overlap the first web 15a when viewed from the front in a direction along the rotational axis of the brake drum 14 (direction shown in FIG. 1), and extends long along the longitudinal direction of the first web 15a.

An engagement piece 36 fixed to one end of the brake cable 37 is engaged with one end (the lower end in this embodiment) of the parking brake lever 34, and the other end (the lower end in this embodiment) of the parking brake lever 34 is engaged with the engagement piece 36 fixed to one end of the brake cable 37. In the embodiment, the upper end portion) is connected to the other end portion of the first web 15a of the first brake shoe 15 via a pin 35.

When the parking brake of the vehicle is activated, the parking brake lever 34 is rotated and driven counterclockwise in FIG. 1 with the pin 35 as a fulcrum by the traction force input from the brake cable 37. As the lever 34 rotates, a force is applied to the second brake shoe 16 via the contraction position regulating strut 24 in a direction that presses the second lining 16c of the brake shoe 16 against the inner periphery of the brake drum 14. It works. Further, when the parking brake lever 34 is continuously rotated and driven in the counterclockwise direction in FIG. Rotating as a fulcrum, the first brake shoe 15 is expanded via the pin 35, and the first lining 15c of the first brake shoe 15 is brought into pressure contact with the inner periphery of the brake drum 14. It turns out. That is, the parking brake lever 34 is operated to an operating position in which the first and second linings 15c and 16c of the first and second brake shoes 15 and 16 are in pressure contact with the inner periphery of the brake drum 14. , In this state, the parking brake state is obtained.

Further, when the application of the rotational driving force to the parking brake lever 34 is stopped by loosening the brake cable 37, the first brake lever is actuated by the spring force of the return spring 19 in the direction away from the inner periphery of the brake drum 14. The parking brake lever 34 returns to the non-operating position together with the second brake shoes 15 and 16, and the parking brake lever 34 is biased toward the non-operating position.

Referring also to FIG. 2, the brake cable 37 is pulled by the power exerted by an electric actuator 38, and the electric actuator 38 has a threaded shaft 39 connected to the brake cable 37, and a screw shaft 39 connected to the brake cable 37. An actuator case 40 that supports the screw shaft 39 while preventing its rotation while allowing reciprocating motion in the axial direction; an electric motor 41 that is supported by the actuator case 40 and capable of forward and reverse rotation; and the electric motor 41. A motion conversion mechanism 42 (see FIG. 3), which is interposed between the electric motor 41 and the screw shaft 39 and housed in the actuator case 40, is capable of converting the rotational motion of the screw shaft 39 into a linear motion of the screw shaft 39. ).

The actuator case 40 of this electric actuator 38 is attached to the back plate 13 via an attachment member 43 on the opposite side from the wheel cylinder 17. The mounting member 43 is fixed to the actuator case 40, and is fastened to the back plate 13 with a plurality of bolts 44, for example, three bolts.

Further, at least a portion of the brake cable 37 that is routed outside the back plate 13 is covered with a cylindrical member, and in this embodiment, for example, a member made of an iron wire wound in a coil shape is used. At least a portion of the brake cable 37 that is routed outside the back plate 13 is covered with the outer cable 45 . Further, the cylindrical member may be any member that can receive the reaction force generated by the output of the electric actuator 38, and a metal cylindrical member may be used in place of the outer cable 45.

Referring also to FIG. 3, the screw shaft 39 of the electric actuator 38 is connected to the brake cable 37 via a cable joint 51, and the connection portion between the screw shaft 39 and the brake cable 37 is as follows: It is covered with a protection tube 50 that is coupled to the actuator case 40 , and the end of the outer cable 44 on the electric actuator 38 side is attached to the protection tube 50 via a guide tube 52 .

A cylindrical portion 13b is integrally provided at the front portion of the lower part of the back plate 13 along the longitudinal direction of the vehicle, and the brake cable 37 covered with the outer cable 45 is connected from the cylindrical portion 13b to the back plate. It will be introduced within 13.

Further, between one end portions of the first and second webs 15a and 16a, a presser plate 46 that sandwiches the anchor plate 21 and the back plate 13 is connected to the back plate by a pair of rivets 47 together with the anchor plate 21. A guide portion 46a that is attached to the lower part of the brake cable 13 and guides the brake cable 37 together with the outer cable 44 is integrally provided on the presser plate 46 so as to have a substantially U-shaped cross-sectional shape.

The actuator case 40 includes a case main body 57 integrally having first and second housing cylinder parts 55 and 56, a first cover member 58 coupled to the open end of the first housing cylinder part 55, and a first housing cylinder part 55. It is composed of a first cover member 58 and a second cover member 59 that is coupled to the case main body 57 from the opposite side.

The first housing cylinder portion 55 is formed into a bottomed cylindrical shape with a first end wall portion 55a provided at one end, and a fitting portion is provided at the center of the first end wall portion 55a. A hole 60 is formed coaxially. The second accommodating cylindrical part 56 is disposed on the side of the first accommodating cylindrical part 55, has one end open, and has a second accommodating cylindrical part 56 disposed at a longitudinally intermediate part of the first accommodating cylindrical part 55. It is formed into a bottomed cylindrical shape with the other end closed by an end wall 56a, and a cylindrical tube 56b surrounding the screw shaft 39 is integrally formed in the center of the second end wall 56a. It will be installed protrudingly. Further, a boot 80 is provided between the protruding end of the screw shaft 39 from the cylindrical portion 56b and the cylindrical portion 56b.

A cylindrical first bearing portion 63a that rotatably supports a motor shaft 64 is protruded from one axial end of the motor case 63 of the electric motor 41, and one end of the motor shaft 64 is connected to the first bearing. A second cylindrical portion with a bottom extends through the portion 63a and protrudes from one end of the motor case 63, and is provided at the other axial end of the motor case 63 to rotatably support the other end of the motor shaft 64. A bearing portion 63b is provided in a protruding manner.

This electric motor 41 causes one end portion of the motor case 63 to abut against the first end wall portion 55a while fitting the first bearing portion 63a into the fitting hole 60 of the case main body 57. The electric motor 41 is housed in the first accommodating cylindrical portion 55 in this way, and the other end of the motor case 63 on the side where the second bearing portion 63b is provided faces the outside. is accommodated in the first accommodating cylinder portion 55.

The first cover member 58 covers a portion of the electric motor 41 accommodated in the first accommodating cylindrical portion 55 that faces outside from the first accommodating cylindrical portion 55 . It integrally includes a lid part 58a coupled to the opening end and a connector part 58b (see FIG. 2) that protrudes laterally from the lid part 58a and is disposed on the side of the first housing cylinder part 55. However, a wave washer 66 is interposed between the second bearing portion 63b of the electric motor 41 and the lid portion 58a. The second cover member 59 is coupled to the case main body 57 so as to form a gear chamber 65 between the second cover member 59 and the case main body 57, and the motion converting mechanism 42 is accommodated in this gear chamber 65.

The motion conversion mechanism 42 includes a drive gear 67 provided on the motor shaft 64 of the electric motor 41, an intermediate large-diameter gear 68 that meshes with the drive gear 67, and an intermediate small-diameter gear that rotates together with the intermediate large-diameter gear 68. 69, a driven gear 70 that meshes with the intermediate small diameter gear 69, and a nut 71 that is integrally provided with the driven gear 70.

The intermediate large-diameter gear 68 and the intermediate small-diameter gear 69 are integrally formed and rotatably supported by a support shaft 72 parallel to the motor shaft 64 and the screw shaft 39. Further, both ends of the support shaft 72 are supported by the case main body 57 and the second cover member 59.

The nut 71 includes a large-diameter cylindrical portion 71a that is rotatably housed in the second accommodating cylindrical portion 56, and a radius from the end of the large-diameter cylindrical portion 71a on the opposite side of the second cover member 59. an inward flange portion 71b that projects inward in the direction; and a small diameter cylindrical portion 71c that is continuous with the inner peripheral edge of the inward flange portion 71b, extends on the opposite side of the second cover member 59, and allows the screw shaft 39 to pass through. and an outward flange portion 71d that protrudes radially outward from the end of the large diameter cylindrical portion 71a on the second cover member 59 side. A female thread 67 is formed on the inner periphery of the small diameter cylindrical portion 71c to be screwed into the screw shaft 39, and the driven gear 70 is formed on the outer periphery of the outward facing flange 71d. Further, a ball bearing 74 is interposed between the small diameter cylindrical portion 71c and the end of the second housing cylinder portion 56 on the second end wall portion 56a side.

At the end of the threaded shaft 39 on the opposite side from the brake cable 37, a protrusion 39a is provided that projects toward both sides along one diameter line of the threaded shaft 39. On the other hand, a recess 75 defined by the large diameter cylindrical portion 71a and the inward flange 71b of the nut 71 is formed in the nut 71 so as to open toward the protrusion 39a.

By the way, when the screw shaft 39 pulls the brake cable 37 to drive the parking brake lever 34 to the operating position, the protrusion 39a moves away from the nut 71, and the parking brake lever When loosening the brake cable 37 in order to return the brake cable 34 from the operating position to the non-operating position, the protrusion 39a moves toward the nut 71, and the protrusion 39a moves in the direction of loosening the brake cable 37. A plurality of disc springs 76 are interposed between the protrusion 39a and the nut 71 when the screw shaft 39 moves, and exert an elastic force that biases the protrusion 39a away from the nut 71. is accommodated in the recess 75.

The concave portion 75 accommodates a plurality of disc springs 76 and a disc-shaped retainer 77 that sandwiches the disc springs 76 between the disc springs 76 and the inward flange 71b of the nut 71.

The second cover member 59 of the actuator case 40 is integrally formed with a bottomed cylindrical guide tube portion 59a that surrounds the screw shaft 39. A pair of locking grooves 78 are formed that extend in the direction along the axis of the screw shaft 39 and slidably engage the protrusion 39a.

A bearing member 79 that receives a thrust load from the nut 71 is interposed between the open end of the guide cylinder portion 59 a and the nut 71 . It integrally has a cylindrical portion 79a.

Here, when pulling the brake cable 37 in order to drive the parking brake lever 34 from the non-operating position to the operating position, the forward rotation of the electric motor 41 causes the threaded shaft 39 to rotate at its protrusion 39a. moves in a direction away from the retainer 77, but the outer peripheral part of the retainer 72 contacts the short cylindrical part 79a of the bearing member 79, thereby preventing the disc spring 76 from leaving the recess 75. Ru. Further, when the electric motor 41 is reversely operated to loosen the brake cable 37, the screw shaft 39 moves in a direction in which the protrusion 39a approaches the retainer 77, but the brake cable 37 moves toward the non-operating position. Since the electric motor 41 is biased by the spring toward the retainer 77, the electric motor 41 is in a no-load state until the protrusion 39a abuts the retainer 77, and after the protrusion 39a abuts the retainer 77, the electric motor 41 is in a no-load state. The elastic force of the disc spring 76 acts on the portion 39a via the retainer 77, and a load is applied to the electric motor 41.

In FIG. 4, electric power from a power source 81 is supplied to the electric motor 41 in the electric actuator 38 via a drive circuit 82, and the operation of the electric motor 41, that is, the operation of the drive circuit 82 is controlled by a control unit. Controlled by C. This control unit C includes an instruction means 83 that detects that the vehicle user performs an operation to release the parking brake state and outputs a signal for releasing the parking brake state, and an instruction means 83 that outputs a signal for releasing the parking brake state, and an instruction means 83 that outputs a signal for releasing the parking brake state, and A current detecting means 84 for detecting the energizing current and a voltage detecting means 85 for detecting the energizing voltage to the electric motor 41 are connected.

As a part related to releasing the parking brake state, the control unit C moves the parking brake lever 34, which is in the operating position in the parking brake state, to the non-operating position in response to a signal input from the instruction means 83. energization control means 86 for controlling the operation of the drive circuit 82 so as to start energization of the electric motor 41 to the returning side; and slope calculation means 87 for calculating the slope of the current value detected by the current detection means 84. , a current stabilization determining means 88 that determines whether or not the energizing current has stabilized after the start of energization to the electric motor 41; A storage means 89 for storing the slope of the current value calculated by the slope calculation means 87 up until just before this, and a slope of the current value stored in the storage means 89 while the electric motor 41 is under load. motor stop determination means 90 for inputting a signal for stopping the operation of the electric motor 41 to the energization control means 86 based on the slope calculation means 87 calculating the slope of the current value on the increasing side other than the above; include.

When releasing the parking brake state, the control unit C controls the operation of the electric motor 41 according to the procedure shown in FIGS. 5 to 7, and starts reverse rotation of the electric motor 41 in step S1 in FIG. In step S2 after inputting a signal from the energization control means 86 to the drive circuit 82, the current value A(n) detected by the current detection means 84 is obtained, and in the next step S3, the flag FI1 is set to " 1”. This flag FI1 is for determining the start of an inrush current, and when it is determined that FI1 is "0" in step S3, the current value A(n) is determined to be equal to or higher than the inrush current start determination current A0 in step S4. When it is determined that A(n)≧A0, the process proceeds from step S4 to step S5, sets the flag FI1 to “1”, returns to step S2, and again calculates A(n). )<A0, the process proceeds from step S4 to step S6, sets the flag FI1 to "0," and then returns to step S2.

When it is confirmed in step S3 that FI1=1, the process proceeds to step S7 and it is determined whether the flag FI2 is "1". This flag FI2 is for determining the end of the inrush current, and when it is determined that FI2 is "0" in step S7, the current value A(n) is determined to be less than or equal to the inrush current end determination current A1 in step S8. When it is determined that A(n)≦A1, the process advances from step S8 to step S9, sets the flag FI2 to "1," returns to step S2, and returns to A(n). )>A1, the process proceeds from step S8 to step S10, sets the flag FI2 to "0," and then returns to step S2.

The processing from step S1 to step S10 described above is performed by the current stabilization determination means 88, and as shown in FIG. The current after passing through the current unstable state due to the inrush current immediately after the start of energization from time t1 when the current value A(n) becomes equal to or higher than the inrush current start determination current A0 and then becomes equal to or less than the inrush current end determination current A1. It will enter a stabilizing state.

When it is confirmed in step S7 that the flag FI2 has become "1", the process proceeds from step S7 to step S11, and the voltage value V(n) detected by the voltage detection means 85 is acquired in step S11. In the next step S12, it is determined whether the voltage value V(n) is less than or equal to the first set voltage value VA, and if V(n)≦VA, the process proceeds to step S13 and the first set voltage value TA is set. is set as TA1. Further, when it is determined in step S12 that V(n)>VA, the process proceeds from step S12 to step S14, and in this step S14, it is determined whether the voltage value V(n) is less than or equal to the second set voltage value VB. However, when V(n)≦VB, the process advances to step S15 and sets the first set time TA to TA2, and when V(n)>VB, the process advances to step S16 and sets the first set time TA. Defined in TA3.

That is, in steps S11 to S16, the first set time TA is set to three values of TA1, TA2, and TA3 according to the voltage value V(n) detected by the voltage detecting means 85. After the processes of steps S13, S15, and S16 described above are completed, the process proceeds to step S17 in FIG. After setting the count value to "0", a count is executed by the first timer in the next step S19, and a current value A(n) detected by the current detecting means 84 is obtained in the next step S20.

In step S21 following step S20, the slope of the current value is calculated by the slope calculating means 87. In this embodiment, the slope calculating means 87 calculates the current value A(n) obtained this time and the slope calculating means The difference from the current value A(n-1) obtained in the previous calculation before the calculation cycle in 87 is calculated as a value representing the slope of the current value.

In step S22 following step S21, it is determined whether the slope of the current value is less than or equal to a first predetermined value SA, and if the slope of the current value≦SA, the process proceeds to step S23 and the flag FS1 is set to "1". After determining this, the process advances to step S24. When it is determined in step S22 that the slope of the current value is greater than SA, it is determined in step S25 whether the slope of the current value is less than or equal to a second predetermined value SB that is larger than the first predetermined value SA. If it is determined in this step S25 that the slope of the current value ≦SB, the process advances to step S26, where the flag FS2 is set to "1", and then the process advances to step S24, and if it is determined that the slope of the current value>SB, the process advances to step S25. The process then proceeds to step S27, where it is determined whether the slope of the current value is less than or equal to a third predetermined value SC, which is greater than the second predetermined value SB. If it is determined in this step S27 that the slope of the current value ≦SC, the flag FS3 is set to "1" in step S28, and the process proceeds to step S24. If the slope of the current value is >SC, the flag FS4 is set to "1" in step S28. 1'', the process advances to step S24.

In step S24, it is determined whether or not the time measurement by the first timer has reached the first set time TA. If it has not reached the first set time TA, the process returns to step S19 and the first set time TA is determined. When it is determined that this has been reached, the process advances to step S30 in FIG.

The processing of steps S17 to S29 described above is performed by the storage means 89, and as shown in FIG. 8, from time t1 when the current destabilization state due to rush current ends to just before time t3 when the electric motor 41 is loaded. The slope of the current value calculated by the slope calculation means 87 is set to flags FS1, FS2, FS3, By setting FS4 to "1", flags FS1, FS2, FS3, The storage means 89 stores the data while attaching FS4.

Moreover, among the slopes of the current values stored by the storage means 89, the slope of the current values used by the motor stop judgment means 90 to judge whether to stop the operation of the electric motor 41 is larger than the first predetermined value SA, and is set within a range that is less than or equal to a predetermined value SC.

In step S30 of FIG. 7, the current value A(n) detected by the current detection means 84 is obtained, and in the subsequent step S31, the slope of the current value is calculated by the slope calculation means 87. , similarly to step S21 described above, the slope calculating means 87 calculates the difference between the current value A(n-1) obtained in the previous calculation before the calculation period in the slope calculating means 87 and calculates the slope of the current value. Calculate as a representative value.

In step S32, it is determined whether the slope of the current value is less than or equal to the first predetermined value SA, and when the slope of the current value is less than or equal to the first predetermined value SA, the count value by the second timer is determined in step S33. After setting it to "0", the process proceeds to step S39, and when the slope of the current value exceeds the first predetermined value SA, the process proceeds from step S32 to step S34. In this step S34, it is determined whether the slope of the current value is below the second predetermined value SB and the flag FS2 is "0", and whether the slope of the current value is below the second predetermined value SB and When the flag FS2 is "0", the second timer performs counting in step S35, and then the process proceeds to step S39, and when the slope of the current value exceeds the second predetermined value SB or the flag FS2 is "1", the process proceeds to step S39. , the process proceeds from step S34 to step S36. In step S36, it is determined whether the slope of the current value is below the third predetermined value SC and the flag FS3 is "0", and whether the slope of the current value is below the third predetermined value SC and the flag FS3 is "0". When FS3 is "0", the second timer performs counting in step S35, and when the slope of the current value exceeds the third predetermined value SC or the flag FS3 is "1", steps S36 to S37 are performed. Proceed to. In step S37, it is determined whether or not the flag FS4 is "0". If FS4=0, the second timer counts in step S35, and if FS4=1, the second timer counts in step S38. After setting the count value by the timer to "0", the process advances to step S39.

As a result of the processing in steps S32 to S39, when a slope of the current value other than the slope of the current value stored in the storage means 89 occurs, that is, it exceeds the first predetermined value SA and is equal to or less than the second predetermined value SB. When the slope of the current value occurs after the first set time TA has elapsed, or when the slope of the current value exceeds the second predetermined value SB and is below the third predetermined value SC, the slope of the current value occurs after the first set time TA. , the second timer performs counting, and when the slope of the current value is the same as the slope of the current value stored in the storage means 89, and the slope of the current value is equal to or lower than the first predetermined value SA. When the current value is a small value, or when the slope of the current value is a large value exceeding the third predetermined value SC, the count value by the second timer is set to "0".

After the second timer counts in step S33, the process advances to step S39, where it is determined whether the elapsed time counted by the second timer exceeds a second set time. This second set time is set as the time required to determine the slope of the current value.

When it is determined in step S39 that the second set time has elapsed, the process proceeds to step S40, where a signal for stopping the electric motor 41 is input to the energization control means 86. If it is determined in step S39 that the second set time has not elapsed, the process proceeds from step S39 to step S41, where it is determined whether the current value A(n) has become equal to or greater than the set current value A2, and A( When n)≧A2, the process proceeds from step S41 to step S40, and when A(n)<A2, the process returns from step S41 to step S39.

The processing in steps S30 to S41 described above is performed by the motor stop determination means 90, and as shown in FIG. When a slope of the current value on the increasing side other than the current value occurs, the motor stop judgment means 90 inputs a signal for stopping the operation of the electric motor 41 to the energization control means 86 at time t4.

Further, after the time t3, the non-detection of the slope of the current value on the increasing side other than the slope of the current value stored in the storage means 89 continues, and as shown by the chain line in FIG. When the current value increases, at time t5 when the current value detected by the current detection means 84 becomes equal to or higher than the set current value A2, the motor stop judgment means 90 sends a signal to the energization control means 86 to stop the operation of the electric motor 41. Enter.

Next, to explain the operation of this embodiment, the control unit C that controls the operation of the electric motor 41 included in the electric actuator 38 includes a slope calculation means 87 that calculates the slope of the current value detected by the current detection means 84, and a parking It is determined based on the current value detected by the current detecting means 84 that the energizing current has stabilized after the start of energization of the electric motor 41 in the direction of returning the parking brake lever 34, which is in the operating position in the brake state, to the non-operating position. current stabilization determining means 88, and a slope of the current value calculated by the slope calculating means 87 within a first set time TA after the current stabilization determining means 88 determines that the energizing current has been stabilized. and the slope calculation means 87 calculates the slope of the current value on the increasing side other than the slope of the current value stored in the storage means 89 after the first set time TA has elapsed. Since the motor stop determination means 90 is configured to stop the operation of the electric motor 41 based on the no-load current state, when the electric motor 41 is loaded after the no-load current state ends, The operation of the electric motor 41 is stopped in response to detecting an increasing slope of the current value other than the slope of the current value caused by noise, and the operation of the electric motor 41 is stopped in response to the detection of an increasing slope of the current value other than the slope of the current value caused by noise. By eliminating the slope of the current value, the operation of the electric motor 41 can be stopped quickly and accurately after the no-load current state has passed.

In addition, the motor stop determination means 90 determines that the current value in a state where the slope of the current value on the increasing side other than the slope of the current value stored in the storage means 89 continues to be undetected after the first set time TA has elapsed. Since it is determined whether or not the electric motor 41 has stopped operating based on the current value detected by the detection means 84, even if it cannot be determined whether the electric motor 41 has stopped operating based on the slope of the current value, the electric motor 41 can be operated reliably based on the current value. Can be stopped.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the gist thereof.

Claims (2)

a parking brake lever (34) that is rotatable between an activated position for obtaining a parking brake state and a non-activated position for releasing the parking brake state, and is resiliently biased toward the non-activated position; Switching between a forward rotation state in which power is exerted to move the parking brake lever (34) from the non-operating position to the operating position and a reverse rotation state in which the parking brake lever (34) is returned from the operating position to the non-operating position. The electric motor (41) may be connected to the parking brake lever (34), and the electric motor (41) may be connected to the parking brake lever (34) after the load on the electric motor (41) becomes no load when the electric motor (41) is reversed. an electric actuator (38) capable of applying a load to the motor (41); a control unit (C) that controls the operation of the electric motor (41); detecting current flowing to the electric motor (41); In the electric parking brake device for a vehicle, the control unit (C) includes a slope calculating means (87) for calculating the slope of the current value detected by the current detecting means (84); The current detecting means detects that the energizing current has stabilized after the start of energizing the electric motor (41) to return the parking brake lever (34), which is in the operating position in the parking brake state, to the non-operating position. current stabilization determining means (88) that makes a determination based on the current value detected by the current stabilization determining means (88); storage means (89) for storing the slope of the current value calculated by 87); and a storage means (89) for storing the slope of the current value on the increasing side other than the slope of the current value stored in the storage means (89) after the elapse of the set time. An electric parking brake device for a vehicle, comprising: motor stop determination means (90) configured to stop the operation of the electric motor (41) based on the calculation by the slope calculation means (87). The motor stop determination means (90) detects the current in a state where the slope of the current value on the increasing side other than the slope of the current value stored in the storage means (89) continues to be non-detected after the set time has elapsed. The electric parking brake device for a vehicle according to claim 1, wherein the electric parking brake device for a vehicle determines whether to stop the operation of the electric motor (41) based on a current value detected by the means (84).

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