JP2005249174A - Drum brake device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drum brake device for a vehicle capable of unifying the distribution of face pressure of linings pressed to an inner peripheral face of a brake drum, and allowing a single brake shoe to function as a leading shoe regardless of forward and backward movement of a vehicle. <P>SOLUTION: The brake shoes 2, 2 are moved in parallel toward an inner peripheral face of the brake drum by allowing actuators 3, 3 to press central parts of inner peripheral parts of the brake shoes 2, 2 radially toward the inner peripheral face of the brake drum, and semicircular-arc shaped linings 1, 1 attached to outer peripheral faces of the brake shoes 2, 2 are uniformly pressed to the inner peripheral face of the brake drum. The linings 1, 1 are uniformly kept into frictional contact with the inner peripheral face of the brake drum while exercising servo effect, when one end part 2A, 2A of each of brake shoes 2, 2 directing to the rotating direction of the brake drum are supported by supporting faces 4A of corresponding anchors 4, 4 in a floated state, whereby the sufficient braking force is applied to the brake drum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a brake device installed in a vehicle, and more particularly to a vehicle drum brake device including a brake shoe in which a lining frictionally contacts an inner peripheral surface of a brake drum.

2. Description of the Related Art As a brake device installed in a vehicle, a drum brake device including a brake shoe in which a lining frictionally contacts an inner peripheral surface of a brake drum is generally known (see, for example, Patent Document 1). There are various types of drum brake devices of this type, such as leading trailing, uni-servo, duo-servo, and two-leading. In any case, one end of the brake shoe is pivot supported or floating supported by an anchor or the like. The other end portion of the brake shoe is pushed by the wheel cylinder so that the lining adhered to the outer peripheral side of the brake shoe is in frictional contact with the inner peripheral surface of the brake drum.
JP-A-7-280002 (FIG. 1)

  By the way, in the conventional drum brake device described above, when the other end portion of the brake shoe is pushed by the wheel cylinder, the brake shoe swings toward the brake drum side with one end portion supported by an anchor or the like as a fulcrum. Accordingly, the lining adhered to the outer peripheral surface of the brake shoe is pressed against the inner peripheral surface of the brake drum and brought into frictional contact. For this reason, the surface pressure distribution of the lining that makes frictional contact with the inner peripheral surface of the brake drum is likely to be non-uniform, resulting in uneven lining wear, unstable fluctuations in the braking force, brake squealing, vibration, etc. Various problems are likely to occur.

  Therefore, the present invention can make the surface pressure distribution of the lining pressed against the inner peripheral surface of the brake drum uniform, and can always cause a single brake shoe to function as a leading shoe regardless of forward and backward movement of the vehicle. It is an object to provide a drum brake device for a vehicle.

  A vehicular drum brake device according to the present invention includes a brake shoe having an arc-shaped lining corresponding to the inner peripheral surface of the brake drum provided on the outer peripheral surface, and a central portion of the inner peripheral portion of the brake shoe disposed on the inner side of the brake drum. It is characterized by comprising an actuator that pushes in the radial direction toward the peripheral surface, and an anchor for floatingly supporting both ends of the brake shoe.

  In the vehicle drum brake device according to the present invention, the actuator pushes the central portion of the inner peripheral portion of the brake shoe in the radial direction toward the inner peripheral surface of the brake drum, whereby the brake shoe is moved to the inner peripheral surface of the brake drum. The arc-shaped lining provided on the outer peripheral surface of the brake shoe is uniformly pressed against the inner peripheral surface of the brake drum. Then, one end of the brake shoe facing the rotation direction of the brake drum is floatingly supported by the anchor corresponding thereto, so that the lining uniformly frictionally contacts the inner peripheral surface of the brake drum while exerting the servo effect, and the brake Sufficient braking force is applied to the drum.

  The vehicle drum brake device of the present invention may be configured to include a single brake shoe, a single actuator corresponding to the single brake shoe, and a pair of anchors, or a pair of brake shoes, A pair of actuators and a pair of anchors corresponding to the pair of brake shoes may be provided. Further, it may be configured to include three brake shoes, three actuators corresponding to the three brake shoes, and three anchors, or four brake shoes and four brake shoes. It may be configured with four corresponding actuators and four anchors.

  Here, when the vehicle drum brake device of the present invention including a pair of brake shoes, a pair of actuators corresponding to the pair of brake shoes, and a pair of anchors is installed for the rear wheel of the vehicle, One actuator can be configured to operate in response to a failure detection signal of a brake device installed for the front wheel of the vehicle.

  In the vehicle drum brake device of the present invention, the actuator that pushes the brake shoe is not limited to a hydraulic wheel cylinder, and may be an electric electric piston.

  According to the vehicle drum brake device of the present invention, the actuator pushes the central portion of the brake shoe in the radial direction of the brake drum, so that the brake shoe moves in parallel toward the inner peripheral surface of the brake drum. The arc-shaped lining provided on the brake shoe is uniformly pressed against the inner peripheral surface of the brake drum, and the surface pressure distribution can be made uniform, resulting in uneven lining wear, unstable fluctuations in brake force, Various problems such as squealing and vibration can be solved.

  In addition, since the end of the brake shoe facing the rotation direction of the brake drum is floatingly supported by an anchor facing the brake shoe, the lining makes frictional contact with the inner peripheral surface of the brake drum while exerting a servo effect. The brake shoe can always function as a leading shoe regardless of whether the vehicle is moving forward or backward, and a sufficient braking force can be generated not only when the vehicle moves forward but also when the vehicle moves backward.

  Embodiments of a drum brake device for a vehicle according to the present invention will be described below with reference to the drawings. In the drawings to be referred to, FIG. 1 is a front view showing the internal structure of the vehicle drum brake device according to the first embodiment of the present invention, and FIG. 2 is a front view showing the internal structure of the vehicle drum brake device according to the second embodiment. 3 and 3 are front views showing the internal structure of the vehicle drum brake device according to the third embodiment.

  As shown in FIG. 1, the vehicular drum brake device according to the first embodiment has a pair of semicircular arc-shaped linings 1 corresponding to the inner peripheral surface of a brake drum (not shown). A pair of brake shoes 2 and 2, and a pair of actuators 3 and 3 that respectively push the central portions of the inner peripheral portions of the pair of brake shoes 2 and 2 radially toward the inner peripheral surface of a brake drum (not shown); A pair of anchors 4 and 4 for floatingly supporting the one end 2A and the other end 2B of the brake shoes 2 and 2 are provided on the back plate 5.

  The pair of brake shoes 2 and 2 are formed in the same shape having a semicircular arc outer peripheral surface and an inner peripheral surface, respectively, and are arranged point-symmetrically on the back plate 5. Concave portions 2C and 2C that are pushed by pistons 3A and 3A of the actuators 3 and 3 are formed at the center of the inner peripheral surfaces of the pair of brake shoes 2 and 2, respectively. Between the pair of brake shoes 2 and 2, a pair of tension springs 6 and 6 that urge them in a direction in which they are separated from the inner peripheral surface of the brake drum (not shown) (a direction in which they are approached to each other) are tensioned. It is installed. The pair of tension springs 6 and 6 are arranged at equal intervals on both sides of a diameter line passing through the central part of the brake shoes 2 and 2.

  The pair of actuators 3 and 3 is constituted by a hydraulic wheel cylinder. The actuators 3 and 3 have the tip portions of the pistons 3A and 3A so that the brake shoes 2 and 2 are pushed radially toward the inner peripheral surface of the brake drum (not shown) by the advancement of the pistons 3A and 3A. The brake shoes 2 and 2 are fixed on the back plate 5 while being engaged with the recesses 2C and 2C.

  The pair of anchors 4, 4 are arranged between one end 2 </ b> A of one brake shoe 2 and the other end 2 </ b> B of the other brake shoe 2, and between the other end 2 </ b> B of one brake shoe 2 and the other brake shoe 2. Is disposed between the first end 2A. These anchors 4 and 4 have support slopes 4A and 4A for floatingly supporting one end portions 2A and 2A of the brake shoes 2 and 2, and support for floatingly supporting the other end portion 2B of the brake shoes 2 and 2. Slopes 4B and 4B are formed.

  The support slopes 4A and 4A and the support slopes 4B and 4B of the anchors 4 and 4 are urged by a pair of tension springs 6 and 6 in a direction away from the inner peripheral surface of the brake drum (not shown) (direction approaching each other). The one end portions 2A, 2A and the other end portions 2B, 2B of the brake shoes 2, 2 are respectively guided to the center side of the back plate 5 so that the pair of brake shoes 2, 2 are aligned concentrically with the brake drum. Inclined to do.

  In the vehicular drum brake device of the first embodiment configured as described above, when the actuators 3 and 3 are actuated by operating a brake pedal (not shown), the pistons 3A and 3A of the actuators 3 and 3 are advanced to the brake shoe. The concave portions 2C and 2C at the center portions of 2 and 2 are pushed in the radial direction toward the inner peripheral surface of the brake drum (not shown). As a result, the brake shoes 2 and 2 move in parallel toward the inner peripheral surface of the brake drum, and the semicircular arc linings 1 and 1 attached to the outer peripheral surface of the brake shoes 2 and 2 are brake drums (not shown). Is uniformly pressed against the inner circumferential surface.

  Here, when the brake drum (not shown) is rotated in the direction of the solid arrow F by the forward movement of the vehicle, the end portions 2A, 2A of the brake shoes 2, 2 facing the rotation direction support the anchors 4, 4, respectively. It is in contact with the inclined surfaces 4A and 4A and is supported in a floating manner. As a result, the semicircular arc-shaped linings 1 and 1 attached to the outer peripheral surfaces of the brake shoes 2 and 2 are in frictional contact with the inner peripheral surface of the brake drum uniformly while exerting the servo effect, and the brake drum is sufficiently braked. Giving power.

  On the other hand, when the brake drum (not shown) rotates in the direction of the broken line arrow R due to the reverse of the vehicle, the other ends 2B and 2B of the brake shoes 2 and 2 facing the rotation direction support the anchors 4 and 4, respectively. It is in contact with the inclined surfaces 4B and 4B and is supported floating. As a result, the semicircular arc-shaped linings 1 and 1 attached to the outer peripheral surfaces of the brake shoes 2 and 2 are in frictional contact with the inner peripheral surface of the brake drum uniformly while exerting the servo effect, and the brake drum is sufficiently braked. Giving power.

  That is, the pistons 3A, 3A of the actuators 3, 3 push the recesses 2C, 2C in the center of the brake shoes 2, 2 in the radial direction of the brake drum (not shown), so that the brake shoes 2, 2 are Therefore, according to the vehicle drum brake device of the first embodiment, the semicircular arc-shaped linings 1 and 1 attached to the outer peripheral surfaces of the brake shoes 2 and 2 are brake drums. It is possible to make uniform contact with the inner peripheral surface by friction and bring the contact pressure distribution into uniform. As a result, it is possible to solve various problems such as uneven wear of the linings 1, 1, unstable fluctuations in braking force, brake squealing phenomenon, and vibration.

  Further, when the vehicle moves forward in which the brake drum (not shown) rotates in the direction of the solid arrow F, the one end portions 2A and 2A of the brake shoes 2 and 2 are floatingly supported on the support slopes 4A and 4A of the anchors 4 and 4, and the lining 1 1 exerts a servo effect, and the other ends 2B and 2B of the brake shoes 2 and 2 are floatingly supported on the support slopes 4B and 4B of the anchors 4 and 4 when the vehicle moves backward with the brake drum rotating in the direction of the broken arrow R. Since the linings 1 and 1 exert a servo effect, the brake shoes 2 and 2 can always function as leading shoes regardless of the forward and backward movement of the vehicle, and the braking force is sufficient not only when the vehicle is moving forward but also when the vehicle is moving backward. Can be generated.

  Next, a vehicular drum brake device according to a second embodiment will be described. This vehicular drum brake device has a pair of brake shoes 2 and 2 and actuators 3 and 3 of the vehicular drum brake device shown in FIG. , 6 have one end locked to the brake shoe 2 and the other end locked to the back plate 5. Other structural parts are the same as those of the vehicular drum brake device shown in FIG.

  Also in the vehicular drum brake device of the second embodiment, the piston 3A of the actuator 3 pushes the recess 2C at the center of the brake shoe 2 in the radial direction of the brake drum (not shown), so that the brake shoe 2 is Since it moves in parallel toward the inner peripheral surface of the brake drum, the semicircular arc-shaped lining 1 adhered to the outer peripheral surface of the brake shoe 2 can be uniformly pressed against the inner peripheral surface of the brake drum and brought into frictional contact. The surface pressure distribution can be made uniform. As a result, it is possible to solve various problems such as uneven wear of the lining 1, unstable fluctuations in brake force, brake squealing phenomenon, and vibration.

  Further, when the vehicle moves forward in which the brake drum (not shown) rotates in the direction of the solid arrow F, the one end portion 2A of the brake shoe 2 is floatingly supported by the support slope 4A of the anchor 4 and the lining 1 exhibits a servo effect. When the vehicle rotates in the direction of the broken line arrow R, the other end 2B of the brake shoe 2 is floatingly supported on the support slope 4B of the anchor 4 and the lining 1 exerts a servo effect. Regardless of this, it can always function as a reading shoe, and a sufficient braking force can be generated not only when the vehicle is moving forward but also when the vehicle is moving backward.

  Here, according to the vehicular drum brake device of the second embodiment, the brake shoe 2 and the actuator 3 each need only one component. Therefore, the number of components compared to the vehicular drum brake device shown in FIG. Weight can be reduced.

  Then, the drum brake device for vehicles concerning a 3rd embodiment is explained. This vehicular drum brake device is obtained by changing the hydraulic pair of actuators 3 and 3 in the vehicular drum brake device shown in FIG. 1 into an electric first actuator 7 and a second actuator 8. Equipped for rear wheels. The other structural parts of the vehicle drum brake device are the same as those of the vehicle drum brake device shown in FIG.

  The first actuator 7 and the second actuator 8 are known electric pistons having a structure in which pistons 7A and 8A connected to a motor via a screw mechanism advance and retreat in accordance with the rotation direction of the motor (Japanese Patent Publication No. 5-63655 or Japanese Patent Publication No. Table 2002-505733 gazette). The first actuator 7 and the second actuator 8 push the brake shoes 2 and 2 in the radial direction toward the inner peripheral surface of the brake drum (not shown) by the advancement of the pistons 7A and 8A. Pistons 7A and 8A are fixed on the back plate 5 with the tip portions engaged with the recesses 2C and 2C of the brake shoes 2 and 2, respectively.

  Here, the first actuator 7 is actuated in response to a depressing operation of a brake pedal (not shown), and the second actuator 8 is activated only when it is determined that the brake device mounted on the front wheel of the vehicle is broken. The operation of the first actuator 7 and the second actuator 8 is controlled by the brake control device 9 shown in FIG. 4 so as to operate.

  The brake control device 9 is configured using microcomputer hardware and software such as an ECU (Electric Control Unit) (not shown), and stores programs and data in addition to the input / output interface I / O and A / D converter. As a hardware, a read only memory (ROM), a random access memory (RAM) that temporarily stores input data, a CPU (Central Processing Unit) that executes a program, and the like are provided. The brake control device 9 includes a front wheel brake failure determination reference value output unit 9A, a data table 9B, a front wheel brake failure detection unit 9C, a first actuator drive signal output unit 9D, and a second actuator drive signal output unit 9E. It is configured as.

  Here, as shown in FIG. 5, when the brake device mounted on the front wheel (not shown) operates normally, the deceleration of the vehicle greatly increases as shown by the solid line in accordance with the increase in the depressing force of the brake pedal. When the front wheel brake device is out of order, the deceleration of the vehicle is halved as shown by the broken line. Therefore, in order to determine the failure of the front wheel brake device, in the data table 9B, the vehicle deceleration predicted at the time of the failure of the front wheel brake device indicated by the broken line in FIG. 5 is stored as a failure determination reference value corresponding to the brake pedaling force. Has been.

  A front wheel brake failure determination reference value output unit 9A, a first actuator drive signal output unit 9D, and a second actuator drive signal output unit 9E are supplied from a brake pedal depression force sensor 10 that detects a depression force when a brake pedal is depressed (not shown). A pedaling force detection signal is input in response to the depression operation of the brake pedal. Further, a deceleration detection signal from the vehicle deceleration sensor 11 that detects the deceleration of the vehicle is input to the front wheel brake failure detection unit 9C.

  When the pedal force detection signal is input from the brake pedal depression force sensor 10, the front wheel brake failure determination reference value output unit 9A looks up the data table 9B, and thereby detects the front wheel brake device corresponding to the detected value of the depression force detection signal. The failure determination reference value is output to the front wheel brake failure detection unit 9C.

  When the failure determination reference value is input from the front wheel brake failure determination reference value output unit 9A, the front wheel brake failure detection unit 9C is input from the vehicle deceleration sensor 11 indicating the failure determination reference value and the actual vehicle deceleration. The detected value of the deceleration detection signal is compared. Then, the front wheel brake failure detection unit 9C determines that the front wheel brake device has failed only when the detected value of the vehicle deceleration is equal to or less than the failure determination reference value, and determines the second actuator drive signal output unit 9E. Outputs a fault detection signal.

  When the pedal effort detection signal is input from the brake pedal effort sensor 10, the first actuator drive signal output unit 9D outputs a drive signal having a magnitude corresponding to the detected value to the first actuator drive circuit 12, Actuator 7 is operated according to the depression force of the brake pedal. On the other hand, when the pedal force detection signal is input from the brake pedal pressing force sensor 10, the second actuator drive signal output unit 9 </ b> E only applies the brake pedal pressing force sensor when the failure detection signal is input from the front wheel brake failure detection unit 9 </ b> C. A drive signal having a magnitude corresponding to the detection value of the pedal effort detection signal input from 10 is output to the second actuator drive circuit 13 and the second actuator 8 is operated according to the pedal effort of the brake pedal.

  In the vehicle drum brake device of the third embodiment configured as described above, for example, when a brake pedal (not shown) is depressed while the vehicle is running, the first actuator 7 and the second actuator 8 shown in FIG. Is controlled by the brake control device 9 shown in FIG. 4 according to the processing procedure of the flowchart shown in FIG.

  First, in step S1, a brake pedal depression force detection signal is input from the brake pedal depression force sensor 10 to the front wheel brake failure determination reference value output unit 9A, the first actuator drive signal output unit 9D, and the second actuator drive signal output unit 9E. . In the subsequent step S2, a drive signal having a magnitude corresponding to the detected value of the pedaling force detection signal is output from the first actuator drive signal output unit 9D to the first actuator drive circuit 12. Thereby, the 1st actuator 7 act | operates according to the depressing force of a brake pedal.

  In step S3, a vehicle deceleration detection signal is input from the vehicle deceleration sensor 11 to the front wheel brake failure detection unit 9C. In subsequent step S4, the data table 9B is looked up by the front wheel brake failure determination reference value output unit 9A. In step S5, the failure determination reference value of the front wheel brake device is output from the front wheel brake failure determination reference value output unit 9A to the front wheel brake failure detection unit 9C.

  In step S6, whether the detected value of the deceleration detection signal input from the vehicle deceleration sensor 11 by the front wheel brake failure detection unit 9C is equal to or less than the failure determination reference value input from the front wheel brake failure determination reference value output unit 9A. It is determined whether or not. And if the determination result of step S6 is YES, it will determine with the front-wheel brake device having failed, and a failure detection signal will be output from the front-wheel brake failure detection part 9C to the 2nd actuator drive signal output part 9E ( Step S7). If the determination result in step S6 is NO, the subsequent step S8 is passed and the series of processes is completed.

  In the subsequent step S8, a drive signal having a magnitude corresponding to the detected value of the pedaling force detection signal from the brake pedal pedaling force sensor 10 is output from the second actuator driving signal output unit 9E to the second actuator driving circuit 13. Thereby, the 2nd actuator 8 act | operates according to the depressing force of a brake pedal.

  As a result of such a series of processing by the brake control device 9, in the vehicle drum brake device of the third embodiment, when the front wheel brake device (not shown) is operating normally, only the first actuator 7 exerts the pedaling force of the rake pedal. When it is determined that the front wheel brake device is malfunctioning, the first actuator 7 and the second actuator 8 are operated according to the depression force of the rake pedal.

  When the front wheel brake device is in a normal operating state and only the first actuator 7 is operated, the piston 7A of the first actuator 7 moves the recess 2C in the center of one brake shoe 2 into the brake drum (not shown). The one brake shoe 2 moves in parallel toward the inner peripheral surface of the brake drum. Then, the semicircular lining 1 attached to the outer peripheral surface of one brake shoe 2 is uniformly pressed against the inner peripheral surface of the brake drum (not shown), so that a sufficient braking force is applied to the brake drum. Is done.

  Further, when the front wheel brake device is in a failure state and the second actuator 8 is activated in addition to the first actuator 7, the piston 8 </ b> A of the second actuator 8 forms the recess 2 </ b> C at the center of the other brake shoe 2. By pushing in the radial direction of a brake drum (not shown), the other brake shoe 2 is also translated toward the inner peripheral surface of the brake drum. The semicircular lining 1 attached to the outer peripheral surface of the other brake shoe 2 is also uniformly pressed against the inner peripheral surface of the brake drum (not shown), so that the brake drum has a pair of brake shoes 2. A large braking force that can cope with a failure of the front wheel brake device is applied by the pair of linings 1 and 2.

  Also in the third embodiment, the semicircular arc-shaped lining 1 stuck to the outer peripheral surface of the brake shoe 2 can be uniformly pressed and brought into frictional contact with the inner peripheral surface of the brake drum. Since the distribution can be made uniform, it is possible to solve various problems such as uneven wear of the lining 1, unstable fluctuations in braking force, brake squealing phenomenon, and vibration.

  Further, when the vehicle moves forward in which the brake drum (not shown) rotates in the direction of the solid arrow F, the one end portion 2A of the brake shoe 2 is floatingly supported by the support slope 4A of the anchor 4 and the lining 1 exhibits a servo effect. When the vehicle rotates in the direction of the broken line arrow R, the other end 2B of the brake shoe 2 is floatingly supported on the support slope 4B of the anchor 4 and the lining 1 exerts a servo effect. Regardless of this, it can always function as a reading shoe, and a sufficient braking force can be generated not only when the vehicle is moving forward but also when the vehicle is moving backward.

  The vehicle drum brake device according to the present invention is not limited to the first to third embodiments. For example, the brake shoe 2 shown in FIG. 1 is changed to three or four small brake shoes arranged at equal angular intervals in the circumferential direction along the inner peripheral surface of a brake drum (not shown). Correspondingly, the number of anchors and actuators can be three or four.

It is a front view showing an internal structure of a drum brake device for vehicles concerning a 1st embodiment of the present invention. It is a front view which shows the internal structure of the drum brake device for vehicles which concerns on 2nd Embodiment. It is a front view which shows the internal structure of the drum brake device for vehicles which concerns on 2nd Embodiment. It is a block block diagram of the brake control apparatus which controls the action | operation of the 1st actuator shown in FIG. 3, and a 2nd actuator. 6 is a graph showing a relationship between vehicle deceleration and brake pedal depression force stored as a failure determination reference value in the data table shown in FIG. 4. It is a flowchart which shows the process by the brake control apparatus shown in FIG.

Explanation of symbols

1 Lining 2 Brake Shoe 3 Actuator 4 Anchor 5 Back Plate 6 Tension Spring 7 First Actuator 8 Second Actuator 9 Brake Control Device

Claims (5)

  A brake shoe having an arc-shaped lining corresponding to the inner peripheral surface of the brake drum, and a central portion of the inner peripheral portion of the brake shoe are pushed radially toward the inner peripheral surface of the brake drum. A drum brake device for a vehicle, comprising: an actuator; and an anchor for floatingly supporting both ends of the brake shoe.   The vehicle drum brake device according to claim 1, comprising a single brake shoe, a single actuator corresponding to the single brake shoe, and a pair of anchors. Drum brake device.   The drum brake device for a vehicle according to claim 1, comprising a pair of brake shoes, a pair of actuators corresponding to the pair of brake shoes, and a pair of anchors. .   The drum brake device for a vehicle according to claim 3, which is equipped for a rear wheel of a vehicle, wherein one of the pair of actuators receives a failure detection signal of a brake device equipped for a front wheel of the vehicle. A drum brake device for a vehicle which is configured to operate in response.   The vehicle drum brake device according to any one of claims 1 to 4, wherein the actuator is configured by an electric piston.

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