JP2021160475A - Vehicle electric parking brake device - Google Patents

Abstract

To stop operation of an electric motor when an abnormal state occurs even after the start of application of a resilient force of an elastic member to a linear motion member when a parking brake state is released.SOLUTION: In control at the time of parking brake state release, a control unit C sets first and second setting currents as thresholds of a detection current even after the start of application of a resilient force to a linear motion member of an electric actuator even in the other states than an unloaded state, sets first and second predetermined upper limit times and a predetermined lower limit time as thresholds for elapsed time, and thereby, detects an abnormal state to notify a vehicle user of the abnormal state, and stops operation of the electric motor 40.SELECTED DRAWING: Figure 8

Description

The present invention is opposite to the parking brake lever, which enables rotation between the operating position for obtaining the parking brake state and the release position for releasing the parking brake state, and is elastically urged toward the release position side. The rotatable electric motor, the linear motion member that operates linearly according to the operation of the electric motor and is connected to the parking brake lever, and the parking brake lever are rotated toward the release position side to rotate the parking brake. An electric actuator having an elastic member that abuts on the linear motion member to give a load to the electric motor when the linear motion member moves to the side that releases the state, a control unit that controls the operation of the electric motor, and a control unit. The present invention relates to an electric parking brake device for a vehicle including a current detecting means for detecting an energizing current to the electric motor and a notifying means capable of notifying an abnormality of the electric actuator.

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 braking force is released according to the operation of the electric actuator so as to move the parking brake lever to the non-operating position. An electric parking brake device for a vehicle is known in Patent Document 1.

Japanese Unexamined Patent Publication No. 2016-43798

By the way, in the electric parking brake device for vehicles, when the parking brake is released, the load applied to the electric motor of the electric actuator becomes small and a no-load current flows, and the plurality of members constituting the electric actuator are excessively returned and locked. You may fall into a state. Therefore, in the one disclosed in Patent Document 1, an increase in the energizing current to the electric motor is detected by applying a load by a spring to the linear motion member forming a part of the electric actuator, and the parking brake lever is not used. The return to the operating position is read to prevent excessive return, but in the control when the parking brake state is released, the abnormal processing of the electric motor is performed only when there is no load, and it moves linearly. It is impossible to stop the operation of the electric motor when an abnormal state occurs after the load by the spring starts to act on the member.

The present invention has been made in view of such circumstances, and even after the elastic force of the elastic member starts to act on the linear motion member when the parking brake state is released, the operation of the electric motor is stopped when an abnormal state occurs. It is an object of the present invention to provide an electric parking brake device for a vehicle which has been made available.

In order to achieve the above object, the present invention enables rotation between the operating position for obtaining the parking brake state and the release position for releasing the parking brake state, and is elastically urged toward the release position side. A parking brake lever, an electric motor that can rotate in the forward and reverse directions, a linear motion member that operates linearly according to the operation of the electric motor and is connected to the parking brake lever, and the parking brake lever on the release position side. An electric actuator having an elastic member that abuts on the linear motor to give a load to the motor when the linear motor moves to the side that releases the parking brake state by rotating the motor, and the electric motor. In an electric parking brake device for a vehicle including a control unit for controlling operation, a current detecting means for detecting an energizing current to the electric motor, and a notifying means capable of notifying an abnormality of the electric actuator, the control unit is Detection by the first timing means that starts timing in response to the start of energization of the electric motor to the side that returns the parking brake lever in the operating position in the parking brake state to the release position, and the current detection means. When it is determined that the measurement time by the first timing means until the current exceeds the first set current corresponding to the no-load current and then becomes less than the first set current is equal to or less than the first predetermined upper limit time. A first determining means for stopping the timing by the first timing means, a second timing means for starting the timing in response to the determination that the first determining means terminates the timing of the first timing means, and a second. 2. A storage means that starts to memorize while sequentially updating the maximum value of the detected current by the current detecting means according to the time measuring time of the two measuring means exceeds the predetermined lower limit time, and the measuring time by the second timing means is the predetermined lower limit time. When the current detected by the current detecting means remains less than the first set current until a larger second predetermined upper limit time is reached, it is determined that the motor is in an abnormal state, and the operation of the electric motor is stopped. When the current detected by the current detecting means becomes equal to or more than the first set current by the time the time measured by the second timing means reaches the second predetermined upper limit time, the notification means is normally notified of the abnormal state. The maximum value of the detection current stored by the storage means after normally stopping the operation of the electric motor according to the judgment result of the second determination means for stopping the operation of the electric motor and the determination result of the second determination means is the first set current. The first feature is that the notification means includes a third determination means that determines that the abnormal state is present when the current becomes larger than the second set current and causes the notification means to notify the abnormal state.

Further, in the present invention, in addition to the configuration of the first feature, in the first determination means, after the current detected by the current detecting means once exceeds the first set current, the measurement time by the first timekeeping means is second. When the first set current is still exceeded even if the predetermined upper limit time of 1 is exceeded, it is determined that the electric motor is in an abnormal state, the operation of the electric motor is stopped, and the notification means is notified of the abnormal state. It is the feature of 2.

According to the first feature of the present invention, in the control when the parking brake state is released, even after the elastic force of the elastic member starts to act on the linear motion member of the electric actuator even in a state other than the no-load state, it is used as a threshold value of the detected current. By setting the first and second set currents and also setting the first and second predetermined upper limit times and predetermined lower limit times as thresholds for the elapsed time, an abnormal state is detected and notified to the vehicle user. At the same time, the operation of the electric motor can be stopped, and it is possible to prevent the parking brake lever from being returned too much. Moreover, since the state of the parking brake lever is detected by detecting the energizing current to the electric motor, a sensor that directly detects the state of the parking brake lever becomes unnecessary, which can contribute to the reduction of the number of parts. ..

Further, according to the second feature of the present invention, it is possible to detect an abnormal state at the beginning of returning the parking brake lever, stop the electric motor in the abnormal state, and notify the vehicle user of the abnormal state. ..

It is a front view of the drum brake device. It is a cross-sectional view taken along the line 2-2 of FIG. It is a perspective view seen from the 3 arrow view direction of FIG. FIG. 3 is a cross-sectional view taken along line 4-4 of FIG. 3 in a state where the brake cable is loosened. It is sectional drawing corresponding to FIG. 4 in the state which pulled the brake cable. It is a perspective view of an electric actuator. 5 is a cross-sectional view taken along the line 7-7 of FIG. It is a block diagram which shows the structure of the part related to the parking brake release of a control unit. It is a graph which shows the normal change of the energizing current of an electric motor when the parking brake is released. It is a flowchart which shows a part of the control procedure at the time of releasing a parking brake. It is a flowchart which shows the rest of the control procedure at the time of releasing a parking brake.

An embodiment of the present invention will be described with reference to FIGS. 1 to 11 attached. First, in FIGS. 1 to 3, a drum brake device 11 according to the present invention is provided on, for example, the left rear wheel of a four-wheeled vehicle. The drum brake device 11 is slid on the inner circumference of a fixed back plate 13 having a through hole 12 in the center for penetrating the axle 10 of the left rear wheel and a brake drum 14 rotating together with the left rear wheel. The first and second brake shoes 15 and 16 arranged in the back plate 13 so as to be in contact with each other and the first and second brake shoes 15 and 16 exert a force for extended operation. Braking gap automatic adjusting means (so-called auto adjuster) 18 that automatically adjusts the gap between the wheel cylinder 17 fixed to the upper part of the back plate 13 and the first and second brake shoes 15 and 16 and the brake drum 14. And a return spring 19 provided between the first and second brake shoes 15 and 16.

The first and second brake shoes 15 and 16 are connected to the webs 15a and 16a formed in a bow shape along the inner circumference of the brake drum 14 and so as to be orthogonal to the outer periphery of the webs 15a and 16a. The rims 15b and 16b are formed, and the linings 15c and 16c are attached to the outer periphery of the rims 15b and 16b.

The outer end portions of the pair of pistons 20 included in the wheel cylinder 17 are arranged so as to face the webs 15a and 16a at the upper end portions of the first and second brake shoes 15 and 16. Further, at the lower part of the back plate 13, an anchor block 21 serving as a fulcrum at the time of expansion and contraction of the first and second brake shoes 15 and 16 is provided at one end of the first and second brake shoes 15 and 16 ( In this embodiment, the wheel cylinder 17 is fixed so as to support the lower end portion), and the wheel cylinder 17 is operated by the output hydraulic pressure of the master cylinder (not shown) operated by the brake pedal, and the anchor With the block 21 as the fulcrum, the force for driving the first and second brake shoes 15 and 16 to the expanding side is exerted.

A coil spring 22 for urging the lower ends of the webs 15a and 16a of the first and second brake shoes 15 and 16 toward the anchor block 21 is provided between the lower ends of the webs 15a and 16a. The return spring 19 for urging the first and second brake shoes 15 and 16 in the contraction direction is provided between the upper ends of the webs 15a and 16a in the first and second brake shoes 15 and 16.

The braking gap automatic adjusting means 18 is provided between the webs 15a and 16a of the first and second brake shoes 15 and 16, and has a contraction position regulating strut 24 that can be extended by rotation of the adjusting gear 23, and the adjusting gear. An adjust that has a feed claw 25a that engages with 23 and is rotatably supported by the web 16a of the second brake shoe 16 that is one of the first and second brake shoes 15 and 16. It is composed of a lever 25 and an adjust spring 26 that rotationally urges the adjust lever 25 toward the side that rotates the adjust gear 23 in a direction in which the contraction position regulating strut 24 is extended.

The contraction position regulating strut 24 regulates the contraction positions of the first and second brake shoes 15 and 16, and the first brake shoe 15 of the first and second brake shoes 15 and 16 is provided. A first rod 27 having a first engaging portion 27a that engages with the upper part of the web 15a, and a second engaging portion 28a having a second engaging portion 28a that engages with the upper part of the web 16a included in the second brake shoe 16. An adjust bolt in which one end is inserted into the first rod 27 so as to be relatively movable in the axial direction and the other end is screwed coaxially into the second rod 28 and the second rod 28 which is arranged coaxially with the first rod 27. The adjusting gear 23 is arranged between the first and second rods 27 and 28 and is formed on the outer periphery of the adjusting bolt 29.

A first locking recess 30 for engaging the first engaging portion 27a is provided on the upper portion of the web 15a of the first brake shoe 15, and a first locking recess 30 is provided on the upper portion of the web 16a of the second brake shoe 16. A second locking recess 31 for engaging the two engaging portions 28a is provided.

The adjusting lever 25 having a feed claw 25a that engages with the adjusting gear 23 is rotatably supported by the web 16a of the second brake shoe 16 via a support shaft 32, and is supported by the second brake shoe 16 as described above. The adjusting spring 26 is provided between the web 16a and the adjusting lever 25. Moreover, the spring force of the adjust spring 26 is set to be smaller than the spring force of the return spring 19.

According to such braking gap automatic adjusting means 18, when the first and second brake shoes 15 and 16 are extended by the operation of the wheel cylinder 17, the constant value is caused by the wear of the linings 15c and 16c. When expanded as described above, the adjusting lever 25 is rotated around the axis of the support shaft 32 by the spring force of the adjusting spring 26, and the contraction position is regulated in response to the rotation of the adjusting gear 23. The effective length of the strut 24 is increased and corrected.

By the way, in the drum brake device 11, one end of the first and second brake shoes 15 and 16 is rotatably supported by the web 15a of the first brake shoe 15, and the contraction position regulating strut 24 A parking brake lever 34 that is engaged with one end is provided.

The parking brake lever 34 extends vertically so as to partially overlap the web 15a in the first brake shoe-15 in a front view, and the upper end portion of the parking brake lever 34 is a first brake. A first engaging portion 27a included in the contraction position regulating strut 24 is engaged with the upper part of the web 15a of the shoe 15 via a pin 35, and the upper part of the parking brake lever 34.

When the parking brake of the vehicle is activated, the parking brake lever 34 is rotated and driven in the counterclockwise direction of FIG. 1 with the pin 35 as a fulcrum, and the rotation of the parking brake lever 34 causes a second brake. A force in a direction in which the lining 16c of the brake shoe 16 is pressed against the inner circumference of the brake drum 14 acts on the shoe 16 via the contraction position regulating strut 24. Further, when the parking brake lever 34 is continuously rotated and driven in the counterclockwise direction of FIG. 1, the parking brake lever 34 uses the engagement point of the contraction position regulating strut 24 with the first engaging portion 27a as a fulcrum. It rotates, and this time, the first brake shoe 16 expands and operates via the pin 35, and the lining 15c of the first brake shoe 15 comes into pressure contact with the inner circumference of the brake drum 14. That is, the parking brake lever 34 operates at an operating position where the linings 15c and 16c of the first and second brake shoes 15 and 16 are in pressure contact with the inner circumference of the brake drum 14, and the parking brake is in this state. The state will be obtained.

When the application of the rotational driving force to the parking brake lever 34 is stopped, the first and second brake shoes 15 and 16 are operated by the spring force of the return spring 19 in the direction away from the inner circumference of the brake drum 14. At the same time, the parking brake lever 34 returns to the non-operating position, and the parking brake lever 34 is urged toward the non-operating position side.

The parking brake lever 34 is rotationally driven by the power exerted by the electric actuator 36, and the brake cable 37 towed by the electric actuator 36 is pulled by the brake cable 37 to pull the second brake shoe 15. The parking brake lever 34 is rotationally driven so as to press the contraction position regulating strut 24 against the web 15a, and is connected to the lower part of the parking brake lever 34 so as to obtain a parking brake state.

With reference to FIGS. 4 and 5, the electric actuator 36 enables the screw shaft 38 connected to the brake cable 37 and the screw shaft 38 to reciprocate in the axial direction while blocking the rotation thereof. The actuator case 39 that supports it, the electric motor 40 that is supported by the actuator case 39 with free forward and reverse rotation, and the rotary motion generated by the electric motor 40 can be converted into the linear motion of the screw shaft 38. It also includes a motion conversion mechanism 41 interposed between the electric motor 40 and the screw shaft 38 and housed in the actuator case 39.

A bottomed connecting hole 42 is coaxially provided at the end of the screw shaft 38 on the brake cable 37 side, and the end of the brake cable 37 on the electric actuator 36 side is inserted into the connecting hole 42. Will be done. Moreover, an annular groove 43 is formed on the outer periphery of the screw shaft 38 near the opening end of the connecting hole 42, and a part of the screw shaft 38 is formed in a state where the brake cable 37 is inserted into the connecting hole 42. By crimping the annular groove 43 so as to bite into the brake cable 37, the screw shaft 38 is connected to the brake cable 37.

The brake cable 37 is pulled out into the back plate 13 from the electric actuator 36 attached to the back plate 13, and an engaging piece 44 fixed to the other end of the brake cable 37 is a parking brake lever. Engage with the lower end of 34.

As shown in FIG. 5, the electric actuator 36 moves the screw shaft 38 to the side where the brake cable 37 is pulled so as to drive the parking brake lever 34 toward the operating position side, and as shown in FIG. The state in which the screw shaft 38 is moved to the side where the brake cable 37 is loosened in order to return the parking brake lever 34 from the operating position to the non-operating position side is switched by changing the rotation direction of the electric motor 40.

By the way, the anchor block 21 is fixed to the lower part of the back plate 13 by a pair of rivets 52 together with the cable guide 51 that sandwiches the anchor block 21 with the lower part of the back plate 13, and is fixed to the cable guide 51. As is clearly shown in FIG. 2, the guide portion 51a for guiding the brake cable 37 is integrally provided with a substantially U-shaped cross-sectional shape, and the stopper 51b is integrally provided.

As shown by the chain line in FIGS. 1 and 2, the operating end of the parking brake lever 34 is regulated by bringing the lower end portion of the parking brake lever 34 into contact with the stopper 51b in the parking brake state.

Further, the stopper 51b is configured to have elasticity, and in this embodiment, the cable guide 51 is formed in a thin plate shape so as to bend and exert elasticity when the parking brake lever 34 comes into contact with the parking brake lever 34. Will be done.

With reference to FIG. 6, the actuator case 39 is coupled to the case main body 47 having the first and second accommodating cylinders 45 and 46 integrally and the open end of the first accommodating cylinder 45. It is composed of a first cover member 48 and a second cover member 49 coupled to the case main body 47 from the side opposite to the first cover member 48.

The first accommodating cylinder portion 45 is formed in a bottomed cylindrical shape so that a first end wall portion 45a is provided at one end portion, and is fitted to a central portion of the first end wall portion 45a. The holes 50 are formed coaxially. The second accommodating cylinder portion 46 is arranged on the side of the first accommodating cylinder portion 45, has one end opened, and is arranged in the intermediate portion in the longitudinal direction of the first accommodating cylinder portion 45. A bottomed cylindrical shape is formed so that the other end is closed by the end wall portion 46a, and a cylindrical support cylinder portion 46b through which the screw shaft 38 is passed is provided at the center portion of the second end wall portion 46a. It is projected in one piece.

A cylindrical first bearing portion 53a that rotatably supports the motor shaft 54 is projected from one end portion of the motor case 53 of the electric motor 40 in the axial direction, and one end portion of the motor shaft 54 is the first bearing. A bottomed cylindrical second portion that penetrates the portion 53a and protrudes from one end of the motor case 53, and rotatably supports the other end of the motor shaft 54 at the other end in the axial direction of the motor case 53. The bearing portion 53b is projected.

In the electric motor 40, one end of the motor case 53 is brought into contact with the first end wall portion 45a while fitting the first bearing portion 53a into the fitting hole 50 of the case main body 47. In this way, it is accommodated in the first accommodating cylinder portion 45, and a part of the electric motor 40, in this embodiment, the other end portion of the motor case 53 on the side where the second bearing portion 53b is provided. The electric motor 40 is accommodated in the first accommodating cylinder portion 45 so as to face the outside.

The first cover member 48 covers a portion of the electric motor 40 housed in the first storage cylinder portion 45 that faces the outside from the first storage cylinder portion 45 of the first storage cylinder portion 45. A lid portion 48a coupled to the opening end and a terminal 55 (see FIG. 3) connected to the electric motor 40 are arranged so as to project laterally from the lid portion 48a and the first accommodating cylinder portion. A wave washer 56 is interposed between the second bearing portion 53b and the lid portion 48a of the electric motor 40, which integrally has a connector portion 48b arranged on the side of the 45.

Moreover, the first cover member 48 can arbitrarily select the position of the connector portion 48b relative to the first accommodating cylinder portion 45 in the circumferential direction at at least a plurality of locations around the axis of the first accommodating cylinder portion 45. It is possible that the first accommodating cylinder portion 45 is coupled to the first accommodating cylinder portion 45, and the connecting portion 57 of the first accommodating cylinder portion 45 and the lid portion 48a has a circular or regular polygonal cross-sectional shape. It is formed and bonded by adhesion or welding.

In this embodiment, the lid portion 48a is formed in a dish shape open to the side of the first storage cylinder portion 45, and the first lid portion 48a has a circular cross-sectional shape at the open end. An annular recess 58 coaxial with the accommodating cylinder portion 45 of the above is formed. On the other hand, a ring-shaped fitting protrusion 59 that fits into the annular recess 58 is provided at the open end of the first storage cylinder 45, and the joint portion 57 is formed in the annular recess 58. The lid portion 48a and the first accommodating cylinder portion 45 are adhered to each other in a state where the fitting protrusion 59 is fitted, and has a circular cross-sectional shape.

The second cover member 49 is coupled to the case main body 47 so as to form a gear chamber 60 with the case main body 47. In this connection, the second cover member 49 may be bonded or welded to the case main body 47. Further, the motion conversion mechanism 41 includes a nut 61 screwed into the screw shaft 38 as one component, and is housed in the gear chamber 60.

The motion conversion mechanism 41 includes a drive gear 62 provided on the motor shaft 54 of the electric motor 40, an intermediate large-diameter gear 63 that meshes with the drive gear 62, and an intermediate small-diameter gear that rotates together with the intermediate large-diameter gear 63. 64, the nut 61, and a driven gear 65 provided on the nut 61 and meshed with the intermediate small diameter gear 64.

The intermediate large-diameter gear 63 and the intermediate small-diameter gear 64 are integrally formed, and are rotatably supported by a support shaft 66 parallel to the motor shaft 54 and the screw shaft 38. Both ends of the support shaft 66 are supported by the case main body 47 and the second cover member 49.

The nut 61 has a radius from a large-diameter cylindrical portion 61a rotatably housed in the second accommodating cylinder portion 46 and an end portion of the large-diameter cylindrical portion 61a opposite to the second cover member 49. A small-diameter cylindrical portion 61c that extends inwardly extending inward from the inwardly-facing flange portion 61b and extends to the side opposite to the second cover member 49 and penetrates the screw shaft 38. And an outward flange portion 61d that projects outward in the radial direction from the end portion of the large-diameter cylindrical portion 61a on the side of the second cover member 49. A female screw 67 screwed to the screw shaft 38 is engraved on the inner circumference of the small-diameter cylindrical portion 61c, and the driven gear 65 is formed on the outer circumference of the outward flange portion 61d. A ball bearing 68 is interposed between the small-diameter cylindrical portion 61c and the end of the second accommodating cylinder portion 46 on the second end wall portion 46a side.

A flange portion 38a that projects outward in the radial direction is provided at the end of the screw shaft 38 on the side opposite to the brake cable 37. On the other hand, the nut 61 is formed so that the recess 70 defined by the large-diameter cylindrical portion 61a and the inward flange portion 61b of the nut 61 opens toward the flange portion 38a.

By the way, when the brake cable 37 is pulled to drive the parking brake lever 34 toward the operating position, the screw shaft 38 moves to the side where the flange portion 38a separates from the nut 61 as shown in FIG. Then, when the brake cable 37 is loosened in order to return the parking brake lever 34 from the operating position to the non-operating position side, the flange portion 38a moves to the side close to the nut 61 as shown in FIG. When the screw shaft 38 moves in the direction of loosening the brake cable 37, the flange portion 38a is interposed between the flange portion 38a and the nut 61 to urge the flange portion 38a to separate from the nut 61. A plurality of countersunk springs 71 as elastic members that exert elastic force are housed in the recess 70.

The recess 70 accommodates a plurality of the disc springs 71 and a disk-shaped retainer 72 that sandwiches the disc springs 71 between the inward flange portion 61b of the nut 61.

With reference to FIG. 7, the flange portion 38a is formed so as to project radially outward from the screw shaft 38 in a direction along one diameter line of the screw shaft 38. On the other hand, the second cover member 49 of the actuator case 39 is integrally formed with a bottomed cylindrical guide cylinder portion 49a surrounding the screw shaft 38, and the inner surface of the guide cylinder portion 49a is formed on the inner surface of the guide cylinder portion 49a. A pair of locking grooves 73 extending in a direction along the axis of the screw shaft 38 and slidably engaging the flange portion 38a are formed.

A bearing member 74 that receives a thrust load from the nut 61 is interposed between the open end of the guide cylinder portion 49a and the nut 61, and the bearing member 74 is short that is inserted into the recess 70. It has a cylindrical portion 74a integrally.

Here, as shown in FIG. 5, when the brake cable 37 is pulled to drive the parking brake lever 34 from the non-operating position to the operating position side, the outer peripheral portion of the retainer 72 is the bearing member. By contacting the short cylindrical portion 74a of the 74, the disc spring 71 is prevented from being detached from the recess 70. Further, as shown in FIG. 4, when the screw shaft 38 moves so as to loosen the brake cable 37, the elastic force of the disc spring 71 acts on the flange portion 38a via the retainer 72.

By the way, the back plate 13 of the drum brake device 11 mounted on the left rear wheel is integrally provided with a mounting cylinder portion 77 extending rearward and inward in the vehicle width direction. The mounting cylinder portion 77 has a large diameter portion 77a having a step portion 77b interposed between a large diameter cylinder portion 77a having one end opened rearward and inward in the vehicle width direction and the other end of the large diameter cylinder portion 77a. A small-diameter tubular portion 77c coaxially connected to the tubular portion 77a is provided, and a second accommodating tubular portion 46 included in the first cover member 48 in the actuator case 39 of the electric actuator 36 is formed by the large-diameter tubular portion 77a. A C-shaped retaining ring 79 mounted on the outer periphery of the second accommodating tubular portion 46 engages with the locking groove 78 inserted inside and formed on the inner circumference of the large-diameter tubular portion 77a. The actuator case 39 is attached to the mounting cylinder portion 77.

As described above, the actuator case 39 is attached to the mounting cylinder portion 77 of the back plate 13, so that the actuator case 39 is attached to the rear side of the back plate 13 in the vehicle front-rear direction, and the connector portion. The 48b is directed to the rear side in the front-rear direction of the vehicle. Further, between the outer circumference of the small diameter cylinder portion 46b of the second accommodating cylinder portion 46 and the outer circumference of one end portion of the screw shaft 38, a bellows shape covering the protruding portion of the screw shaft 38 from the second accommodating cylinder portion 46. Boots 80 are provided.

In FIG. 8, the electric power of the power supply 81 is supplied to the electric motor 40 in the electric actuator 36 via the drive circuit 82, and the operation of the electric motor 40, that is, the operation of the drive circuit 82 is a control unit. It is controlled by C. The control unit C is provided with an instruction means 83 for detecting that the vehicle user has performed an operation for releasing the parking brake state and outputting a signal for releasing the parking brake state, and the electric motor 40. The current detecting means 84 for detecting the energizing current and the notifying means 85 such as a buzzer or a display for notifying the abnormal state are connected.

The control unit C has, as a part related to the release of the parking brake, an energization control means 86, a first timekeeping means 87, a first determination means 88, a second timekeeping means 89, a storage means 90, and a second. The determination means 91 and the third determination means 92 are provided.

The energization control means 86 energizes the electric motor 40 to the side where the parking brake lever 34 in the operating position in the parking brake state is returned to the release position in response to the signal input from the instruction means 83. A signal for controlling the operation of the drive circuit 82 is output so as to start. Further, the first time measuring means 87 clocks the time TO1 in response to the signal for starting energization of the electric motor 40 being output from the indicating means 83 on the side where the parking brake lever 34 is returned to the release position. Start.

The first determining means 88 is the first timing means 87 until the current AO detected by the current detecting means 84 once exceeds the first set current A1 corresponding to the no-load current and then becomes less than the first set current A1. When it is determined that the measurement time TO1 is equal to or less than the first predetermined upper limit time T1, the time measurement by the first time counting means 87 is stopped, and even if the measurement time TO1 exceeds the first predetermined upper limit time T1. When the first set current A1 is still exceeded, it is determined that the electric motor 40 is in an abnormal state, and a signal for stopping the operation of the electric motor 40 is input to the energization control means 86 and the notification means 85 is notified of the abnormal state. ..

By the way, when the electric motor 40 is energized to the side where the parking brake lever 34 in the operating position is returned to the release position in the parking brake state, the current changes as shown in FIG. 9 in the normal state. The first predetermined upper limit time T1 is set as a sufficient time until it becomes less than the first set current A1 in a normal state.

The second timekeeping means 89 starts the time counting of the time TO2 in response to the determination that the first timing means 88 ends the timekeeping of the first timekeeping means 87. Further, the storage means 90 starts to store while sequentially updating the maximum value Amax of the current AO detected by the current detecting means 84 in accordance with the time counting time TO2 of the second time measuring means 89 exceeding the predetermined lower limit time T2. Here, the predetermined lower limit time T2 is set as an assumed minimum time until the elastic force of the disc spring 71 acts on the screw shaft 38 of the electric actuator 36 via the retainer 72 when the parking brake is released. NS.

In the second determination means 91, the current AO detected by the current detecting means 84 is set to the first setting until the timed time TO2 by the second timing means 89 reaches the second predetermined upper limit time T3 which is larger than the predetermined lower limit time T2. When the current remains less than A1, it is determined that the electric motor 40 is in an abnormal state, and a signal for stopping the operation of the electric motor 40 is input to the energization control means 86 and the notification means 85 is notified of the abnormal state. When the current AO detected by the current detecting means 89 becomes equal to or higher than the first set current A1 by the time the current measuring time TO2 by the timing means 89 reaches the second predetermined upper limit time T3, the electric motor 40 is normally operated. A signal for stopping is input to the energization control means 86. Here, the second predetermined upper limit time T3 is the assumed maximum time until the elastic force of the disc spring 71 acts on the screw shaft 38 of the electric actuator 36 via the retainer 72 when the parking brake is released. Is set as.

In the third determination means 92, the maximum value Amax of the detection current AO stored by the storage means 90 after the operation of the electric motor 40 is normally stopped according to the determination result of the second determination means 91 is the first set current. When the second set current A2 or more, which is larger than A1, is determined to be an abnormal state, the notification means 85 is notified of the abnormal state.

The control procedure when the parking brake is released by the control unit C will be described with reference to FIGS. 10 and 11. First, in FIG. 10, when the parking brake is released, the flag F is set to “0” in step S1. , The detection current AO detected by the current detection means 84 is acquired in step S2, it is determined in step S3 whether or not the flag F is “1”, and when the flag F is “0”, the next step. The process proceeds to S4, and when the flag F is “1”, the process bypasses steps S4 to S8 and proceeds to step S9.

In step S4, the time TO1 by the first timekeeping means 87 is counted, and in the subsequent step S5, it is determined whether or not the detected current AO is less than the first set current A1, and the detected current AO is equal to or larger than the first set current A1. When (AO ≧ A1), the process proceeds to step S6, and when the detected current AO is less than the first set current A1 (AO <A1), the process returns to step S2.

In step S6, it is determined whether or not the timekeeping time TO1 by the first timekeeping means 87 exceeds the first predetermined upper limit time T1, and the timekeeping time TO1 exceeds the first predetermined upper limit time T1 (TO1> T1). When it is determined, the process proceeds to step S17 of FIG. 11, and when it is determined that the timekeeping time TO1 is equal to or less than the first predetermined upper limit time T1 (TO1 ≦ T1), the process proceeds to step S7, and the flag F is set to “1” in this step S7. In the next step S8, the time TO1 is timed by the first time means 87.

In step S9, the counting of the timed time TO2 by the second timed means 89 is started, and in the next step S10, it is determined whether or not the timed time TO2 exceeds the predetermined lower limit time T2, and the timed time TO2 is the predetermined lower limit time. When it is determined that T2 or less (TO2 ≦ T2), the process returns to step S2, and when it is determined that the timekeeping time TO2 exceeds the predetermined lower limit time T2 (TO2> T2), the process proceeds to step S11 and the current detected by the current detecting means 84. The maximum value Amax of AO is stored while being sequentially updated.

In FIG. 11, in step S12 following step S11, it is determined whether or not the timekeeping time TO2 by the second timekeeping means 89 exceeds the second predetermined upper limit time T3, and the timekeeping time TO2 is the second predetermined upper limit time. When it is determined that T3 or less (TO2 ≦ T3), the process proceeds to step S13, and when it is determined that the timekeeping time TO2 exceeds the second predetermined upper limit time T3 (TO2> T3), the process proceeds to step S17.

In step S13, when it is determined whether or not the detected current AO by the current detecting means 84 is equal to or higher than the first set current A1 and it is determined that the detected current AO is equal to or higher than the first set current A1 (AO ≧ A1). When the operation of the electric motor 40 is normally completed in step S14 and it is determined in step S13 that the detected current AO is less than the first set current A1 (AO <A1), the process returns to step S2 in FIG. ..

In step S15 following step S14, it is determined whether or not the maximum value Amax of the detected current AO stored in the storage means 90 is less than the second set current A2, and the maximum value Amax of the detected current AO is the second. When it is determined that the current is less than the set current A2 (Amax <A2), the control procedure for storing the operation information and releasing the parking brake is completed in step S16, and the maximum value Amax of the detected current AO is the second set current A2. When it is determined that the above (Amax ≧ A2), the process proceeds to step S18.

Further, when it is determined in step S6 that the timed time TO1 by the first timed means 87 exceeds the first predetermined upper limit time T1, and in step S12, the timed time TO2 by the second timed means 89 is the second predetermined upper limit time. When it is determined that T3 has been exceeded (TO2> T3), the operation of the electric motor 40 is stopped, assuming that the state is equal to or higher in step S17. Further, in step S18 following step S17, the notification means 85 is notified and operated as being in an abnormal state.

Next, the operation of this embodiment will be described. The drum brake device 11 can obtain the parking brake state by pulling the brake cable 37 connected to the parking brake lever 34 by the electric actuator 36, and is electrically operated. The actuator 36 can satisfactorily control the operation and release of the parking brake.

Moreover, the guide portion 51a for guiding the brake cable 37 is integrally provided with the cable guide 51 fixedly attached to the back plate 13 of the drum brake device 11 and arranged in the back plate 13, and the said Since the stopper 51b that comes into contact with the parking brake lever 34 and regulates the operating end of the parking brake lever 34 is integrally provided on the cable guide 51, the inner surface of the brake drum 14 and the first and second brake shoes 15 and 16 are provided. Excessive operating amount of the parking brake lever 34 during parking braking due to the widening of the gap between the two and the parking brake lever 34 is regulated by the parking brake lever 34 coming into contact with the stopper 51b, and the electric actuator 36. The operating amount of the side component member, for example, the screw shaft 38 becomes too large, for example, the screw shaft 38 operates until it comes into contact with the closed end of the bottomed cylindrical guide cylinder portion 49a of the second cover member 49. Can be prevented. Moreover, since the operating amount of the parking brake lever 34 can be regulated on the drum brake side, the structure of the electric actuator 36 can be simplified.

Further, the cable guide 51 is attached to the back plate 13 together with the anchor block 21 while having a guide portion 51a for guiding the brake cable 37, and the stopper 51b is integrally provided on the cable guide 51. Therefore, a dedicated member for fulfilling the stopper function is not required, and it is possible to avoid an increase in the number of parts and processing man-hours and prevent the operating amount of the parking brake lever 34 from becoming excessive, and the drum brake device 11 The present invention can be satisfactorily applied to the vehicle.

Further, since the stopper 51b is configured to have elasticity, even if the parking brake lever 34 impacts the stopper 51b, the impact can be absorbed, and the constituent members on the electric actuator 36 side, for example, the screw shaft 38 and It is possible to prevent the nut 61 from being locked.

Further, the electric actuator 36 has a screw shaft 38 connected to a brake cable 37 connected to a parking brake lever 34 urged toward a non-operating position side, and a screw shaft 38 in the axial direction while blocking its rotation. The actuator case 39 that enables reciprocating motion, the electric motor 40 that is supported by the actuator case 39 that can freely rotate in the forward and reverse directions, and the nut 61 that meshes with the screw shaft 38 are provided as one component and described above. A motion conversion mechanism interposed between the electric motor 40 and the screw shaft 38 and housed in the actuator case 39 while enabling the rotational motion generated by the electric motor 40 to be converted into a linear motion of the screw shaft 38. The brake cable 37 is provided with 41, and the brake cable 37 is pulled so as to drive the parking brake lever 34 toward the operating position side, and the parking brake lever 34 is returned from the operating position to the non-operating position side. The loosening state can be switched by changing the rotation direction of the electric motor 40, but the screw shaft 38 is provided with a flange portion 38a protruding outward in the radial direction and opens toward the flange portion 38a side. The recess 70 is formed coaxially with the nut 61, and when the screw shaft 38 is moved to the side where the brake cable 37 is loosened, the flange portion 38a is interposed between the flange portion 38a and the nut 61 to form the nut. A countersunk spring 71 that exerts an elastic force that urges the side to be separated from the 61 is housed in the recess 70.

Therefore, the elastic force of the disc spring 71 acts on the screw shaft 38 when the screw shaft 38 is moved to the side where the brake cable 37 is loosened, whereby a load is applied to the electric motor 40 during the return operation. It becomes possible to give. Moreover, since the disc spring 71 is housed in the recess 70 formed in the nut 61 coaxially with the screw shaft 38, it is not necessary to secure an extra space for arranging the disc spring 71, and the actuator case 39 is compact. In addition, since the elastic force of the disc spring 71 acts on the actuator case 39 only during the parking brake, it is not necessary to increase the strength of the actuator case 39 more than necessary.

Further, since a plurality of stacked disc springs 71 are housed in the recess 70, the elastic load can be changed by selecting the number of disc springs 71, and the specifications can be changed according to the type of the electric actuator 36. Becomes easier.

Further, the flange portion 38a is formed so as to protrude outward from the screw shaft 38 in the radial direction in a direction along one diameter line of the screw shaft 38, and is formed on the actuator case 39 on the axis of the screw shaft 38. Since a pair of locking grooves 73 extending along the direction and engaging the flange portion 38a in a slidable manner are formed, it is possible to prevent the screw shaft 38 from rotating while allowing the screw shaft 38 to move in the axial direction. The structure for preventing the rotation of the screw shaft 38 can be simplified.

Further, since the electric actuator 36 is attached to the back plate 13 of the drum brake device 11, the present invention can be satisfactorily applied to the drum brake device 11.

Further, the actuator case 39 of the electric actuator 36 accommodates a first accommodating cylinder portion 45 for accommodating an electric motor 40 that exerts power for obtaining a parking brake state so that a part of the electric motor 40 faces the outside. The case main body 47, a lid portion 48a that covers the part of the electric motor 40 and is coupled to the first accommodating cylinder portion 45, and a terminal 55 connected to the electric motor 40 are arranged. The first cover member 48 is provided with a first cover member 48 that integrally has a connector portion 48b that projects laterally from the lid portion 48a and is arranged on the side of the first storage cylinder portion 45. It is possible to arbitrarily select the circumferential relative position of the connector portion 48b with respect to the first accommodating cylinder portion 45 at at least a plurality of locations, and since it is coupled to the first accommodating cylinder portion 45, it can be laid out for each vehicle type. It is not necessary to make the actuator case 39 at the same time, and the position of the connector portion 48b with respect to the actuator case 39 can be easily changed to give versatility, and the cost increase can be suppressed by making it compatible with various types of vehicles. Can be done.

Further, since the connecting portion 57 of the first accommodating cylinder portion 45 and the lid portion 48a is formed so as to have a circular or regular polygonal cross-sectional shape, the degree of freedom in the position of the connector portion 48b with respect to the actuator case 39. Can be easily changed, and the orientation of the connector portion 48b can be easily changed.

Further, since the actuator case 39 with the connector portion 48b facing the vehicle front-rear direction rear side is attached to the vehicle front-rear direction rear side of the back plate 13 included in the rear wheel drum brake device 11, the connector portion 48b is attached to the vehicle. Since the connector portion 48b faces the rear side in the front-rear direction, the maintainability of the connector portion 48b when mounted on the vehicle can be improved, and the connector portion 48b can be protected from flying stones generated when the vehicle is running.

Further, since the first cover member 48 is bonded or welded to the first accommodating cylinder portion 45, the number of parts is increased when the first cover member 48 is bonded to the first accommodating cylinder portion 45. The first cover member 48 can be reliably connected to the first accommodating cylinder portion 45 while the orientation of the connector portion 48b can be easily changed without increasing the number.

Further, the control unit C that controls the operation of the electric motor 40 measures the current according to the start of energization of the electric motor 40 to the side that returns the parking brake lever 34 in the operating position in the parking brake state to the release position. The first timing means 87 to start and the first time measuring means until the current AO detected by the current detecting means 84 once exceeds the first set current A1 corresponding to the no-load current and then becomes less than the first set current A1. When it is determined that the measurement time TO1 by the 87 is equal to or less than the first predetermined upper limit time T1, the first determination means 88 that stops the timing by the first timing means 87 and the first determination means 88 are the first timing means. The second time measuring means 89 that starts the time measuring according to the determination that the time measuring of the means 87 is terminated, and the current detecting means 84 according to the time measuring time TO2 of the second time measuring means 89 exceeding the predetermined lower limit time T2. The storage means 90 that starts to store the maximum value Amax of the current AO detected by the second timing means 89 while sequentially updating the current, and the second predetermined upper limit time T3 that is larger than the predetermined lower limit time T2. When the current AO detected by the current detecting means 84 remains less than the first set current A1, it is determined that the electric motor 40 is in an abnormal state, the operation of the electric motor 40 is stopped, and the notifying means 85 is notified of the abnormal state. However, when the current AO detected by the current detecting means 84 becomes equal to or higher than the first set current A1 by the time the current TO2 measured by the second measuring means 89 reaches the second predetermined upper limit time T3, the electric motor 40 is normally used. The maximum value Amax of the detection current AO stored by the storage means 90 after the operation of the electric motor 40 is normally stopped is determined by the second determination means 91 for stopping the operation of the electric motor 40 and the determination result of the second determination means 91. It includes a third determination means 92 that determines that an abnormal state is present when the second set current A2 or more is larger than the first set current A1 and causes the notification means 85 to notify the abnormal state.

Therefore, in the control when the parking brake state is released, even after the elastic force of the countersunk spring 71 starts to act on the screw shaft 38 of the electric actuator 39 even in a state other than the no-load state, the first and second set currents are set as the threshold value of the detected current AO. By setting A1 and A2 and also setting the first and second predetermined upper limit times T1 and T3 and the predetermined lower limit time T2 as thresholds for the elapsed time, an abnormal state is detected and notified to the vehicle user. At the same time, the operation of the electric motor 40 can be stopped, and it is possible to prevent the parking brake lever 34 from being returned too much. Moreover, since the state of the parking brake lever 34 is detected by detecting the energizing current to the electric motor 40, a sensor that directly detects the state of the parking brake lever 34 becomes unnecessary, which contributes to a reduction in the number of parts. be able to.

Further, in the first determination means 88, after the current AO detected by the current detection means 84 once exceeds the first set current A1, the measurement time TO1 by the first timekeeping means 87 exceeds the first predetermined upper limit time T1. However, when the first set current A1 is still exceeded, it is determined that the electric motor 40 is in an abnormal state, the operation of the electric motor 40 is stopped, and the notification means 85 is notified of the abnormal state. It is possible to detect an abnormal state at the beginning of returning, stop the electric motor 40 in the abnormal state, and notify the vehicle user of the abnormal state.

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 are made without departing from the present invention described in the claims. Is possible.

34 ... Parking brake lever 38 ... Screw shaft 39 which is a linear motion member ... Electric actuator 40 ... Electric motor 71 ... Countersunk spring 84 which is an elastic member ... Current detection means 85 ... -Notification means 87 ... 1st timekeeping means 88 ... 1st judgment means 89 ... 2nd timekeeping means 90 ... Storage means 91 ... 2nd judgment means 92 ... 3rd judgment means A1 ... 1st set current A2 ... 2nd set current C ... Control unit T1 ... 1st predetermined upper limit time T2 ... Predetermined lower limit time T3 ... Second predetermined upper limit time

Claims (2)

With the parking brake lever (34), which enables rotation between the operating position for obtaining the parking brake state and the release position for releasing the parking brake state, and is urged toward the release position side; forward and reverse rotation. A free electric motor (40), a linear motion member (38) that operates linearly according to the operation of the electric motor (40) and is connected to the parking brake lever (34), and the parking brake lever (34). ) Is rotated to the release position side to give a load to the electric motor (40) when the linear motion member (38) moves to the side to release the parking brake state. An electric actuator (39) having an elastic member (71) in contact with the electric motor (71); a control unit (C) for controlling the operation of the electric motor (40); In an electric parking brake device for vehicles including means (84) and notification means (85) capable of notifying an abnormality of the electric actuator (39), the control unit (C) is in the operating position in the parking brake state. The first timing means (87) that starts timing in response to the start of energization of the electric motor (40) to the side that returns the parking brake lever (34) to the release position, and the current detection means (87). The measurement time by the first timing means (87) until the detection current by 84) once exceeds the first set current (A1) corresponding to the no-load current and then becomes less than the first set current (A1). The first determination means (88) for stopping the timing by the first timing means (87) when it is determined that the time is equal to or less than the predetermined upper limit time (T1) of 1, and the first determination means (88) are the first. The time counting time of the second time measuring means (89) and the second time measuring means (89), which start the time measuring in response to the determination that the time measuring of the time measuring means (87) is to be terminated, exceeds the predetermined lower limit time (T2). The storage means (90) that starts to store while sequentially updating the maximum value (Amax) of the detected current by the current detecting means (84) according to the above, and the timed time by the second timing means (89) is the predetermined lower limit time ( When the detection current by the current detecting means (84) remains less than the first set current (A1) until the second predetermined upper limit time (T3) larger than T2) is reached, it is determined that the state is abnormal. Then, the operation of the electric motor (40) is stopped and the notification means (85) is notified of the abnormal state. When the current detected by the current detecting means (84) becomes equal to or more than the first set current (A1) by the time the time measured by the time means (89) reaches the second predetermined upper limit time (T3), the above is normally performed. The second determination means (91) for stopping the operation of the electric motor (40) and the storage means (91) after normally stopping the operation of the electric motor (40) according to the determination result of the second determination means (91). When the maximum value (Amax) of the detected current stored in 90) becomes greater than or equal to the second set current (A2) larger than the first set current (A1), it is determined that the state is abnormal and the notification means (85) ) Includes a third determination means (92) for notifying the abnormal state. In the first determination means (88), after the current detected by the current detection means (84) once exceeds the first set current (A1), the measurement time by the first timekeeping means (87) is determined as the first. Even if the upper limit time (T1) is exceeded, when the first set current (A1) is still exceeded, it is determined that the electric motor (40) is in an abnormal state, the operation of the electric motor (40) is stopped, and the notification means (85) is used. The electric parking brake device for a vehicle according to claim 1, wherein an abnormal state is notified to the vehicle.

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