Vehicle Brake Device

Abstract

To provide a vehicular brake device which can inhibit complication of wiring without deteriorating detection accuracy of a brake force.SOLUTION: A vehicular brake device includes: a brake rotating body 2 which rotates with a wheel; friction members 31, 32 which are pressed against the brake rotating body 2 during braking; a torque receiving part 4 which prevents rotation of the friction members 31, 32 to provide a brake force to the wheel; a driving device 5 having a fixed part 51 fixed to the torque receiving part 4 and a movable part 52 which drives the friction members 31, 32 to press the friction members 31, 32 to the brake rotating body 2; a load sensor 6 which is installed at the fixed part 51 and detects a force applied to the fixed part 51; and a calculation part 71 which calculates the brake force based on a detection value of the load sensor 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle braking system. [Background technology]

[0002] A known vehicle braking device uses a drum brake, as described in JP 2002-67914 A. In this vehicle braking device, a load sensor is provided on the anchor body to calculate the braking force. With this configuration, the actual braking force can be calculated with high accuracy by detecting the contact load between the brake shoe and the anchor body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-67914 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above vehicle braking device, the anchor body is disposed at the bottom inside the wheel due to its configuration. Therefore, the load sensor installed on the anchor body is also disposed at the bottom inside the wheel. In this arrangement, the wiring of the load sensor must be routed so as to run vertically through the wheel, which tends to make the layout of the wiring that passes between the moving parts such as the hub, the brake shoe, and the arm complicated.

[0005] An object of the present invention is to provide a vehicle braking system that can suppress the complexity of wiring without reducing the accuracy of detecting the braking force. [Means for solving the problem]

[0006] The vehicle braking device of the present invention includes a brake rotor that rotates together with a wheel, a friction member that is pressed against the brake rotor during braking, and a torque receiving portion that applies a braking force to the wheel by preventing rotation of the friction member. Contains the linear motion converter a driving device having a fixed part fixed to the torque receiving part and a movable part that drives the friction member to press it against the brake rotor; and a force sensor that is installed on the fixed part and detects a force applied to the fixed part. One A load sensor; The one a calculation unit that calculates the braking force based on the detection value of the load sensor. The friction member includes a first friction member and a second friction member, and the first friction member and the second friction member are connected by an adjuster that is displaceable relative to the torque receiving portion. Further, a vehicle braking device of the present invention includes a brake rotor that rotates together with a wheel, a friction member that is pressed against the brake rotor during braking, a torque receiving portion that applies a braking force to the wheel by preventing rotation of the friction member, a fixed portion that accommodates a linear motion conversion portion and is fixed to the torque receiving portion, and a drive device having a movable portion that drives the friction member to press it against the brake rotor, a load sensor that is installed on the fixed portion and detects a force applied to the fixed portion, and a calculation portion that calculates the braking force based on a detection value of the one load sensor, wherein the fixed portion is inserted into a through hole of the torque receiving portion and fixed to the torque receiving portion, the load sensor is disposed within the through hole of the torque receiving portion, sandwiched between the torque receiving portion and the fixed portion, and is fixed to the fixed portion by a fixing member, the friction member includes a first friction member and a second friction member, and the first friction member and the second friction member are connected by an adjuster that is displaceable relative to the torque receiving portion. Effect of the Invention

[0007] According to the present invention, the load sensor is disposed in a fixed portion of the drive device that is fixed to the torque receiving portion. Therefore, the load received by the torque receiving portion can be detected with high accuracy. Since the load and the actual braking force correspond with high accuracy, the actual braking force can be calculated with high accuracy. In addition, since the load sensor is provided in the drive device that is generally installed at the top inside the wheel, the complexity of wiring can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a configuration diagram of a vehicle braking device according to a first embodiment (a cross-sectional view seen from the left side of the vehicle). [Diagram 2] 1 is a configuration diagram (a cross-sectional view seen from above the vehicle) of a vehicle braking device according to a first embodiment. [Diagram 3] FIG. 11 is a configuration diagram (sectional view seen from above the vehicle) of a vehicle braking device according to a second embodiment. [Figure 4] FIG. 11 is a configuration diagram (sectional view seen from the left side of the vehicle) of a vehicle braking device according to a third embodiment. [Diagram 5] FIG. 11 is a configuration diagram (sectional view seen from above the vehicle) of a vehicle braking device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings. Also, each drawing used in the description is a conceptual diagram. In the following description, the front of the vehicle is referred to as the front, and the rear of the vehicle is referred to as the rear.

[0010] First Embodiment As shown in Figures 1 and 2, the vehicle braking device 1 of the first embodiment is a duo-servo type drum brake, and includes a rotating drum (corresponding to the "brake rotating body") 2, a first brake shoe (corresponding to the "first friction member") 31, a second brake shoe (corresponding to the "second friction member") 32, an adjuster 33, a back plate 4 that forms a torque receiving portion, a drive device 5, a load sensor 6, and a brake ECU 7.

[0011] The rotating drum 2 is a member that rotates together with the wheel. The first brake shoe 31 and the second brake shoe 32 are friction members that are pressed against the rotating drum 2 during braking. The first brake shoe 31 and the second brake shoe 32 are each a convex arc-shaped member with a lining 30 on the outer periphery. The first brake shoe 31 is a leading shoe that is disposed relatively forward. The second brake shoe 32 is a trailing shoe that is disposed relatively rearward. The first brake shoe 31 and the second brake shoe 32 are disposed in an arc shape.

[0012] The first brake shoe 31 and the second brake shoe 32 are mounted on the back plate 4 by a shoe hold pin (not shown) so that they can be spread apart from each other. The first brake shoe 31 and the second brake shoe 32 are connected by a return spring (not shown) and are configured to return to their initial positions when no force is applied.

[0013] The adjuster 33 is a rod-shaped member that transmits force from one end to the other end and is adjustable in length. The adjuster 33 is also called a shoe adjuster or a floating support. One end (front end) of the adjuster 33 is fixed to the lower end of the first brake shoe 31, and the other end (rear end) of the adjuster 33 is fixed to the lower end of the second brake shoe 32. The adjuster 33 does not abut against the back plate 4 and is movable relative to the back plate 4. In this way, the first brake shoe 31 and the second brake shoe 32 are connected by the adjuster 33, which is displaceable relative to the back plate 4.

[0014] The back plate 4 is fixed to a vehicle body member (not shown) that rotatably supports the wheels. The back plate 4 functions as a torque receiving portion that applies a braking force to the wheels by preventing the rotation of the first brake shoe 31 and the second brake shoe 32. A drive unit 5 is fixed to the back plate 4.

[0015] The drive unit 5 is an actuator that drives the first brake shoe 31. The drive unit 5 of the first embodiment constitutes an electric mechanical brake (EMB) that drives a first piston 52 with an electric motor 55. The drive unit 5 is disposed between an upper end of the first brake shoe 31 and an upper end of the second brake shoe 32. The drive unit 5 includes a fixed part 51, a first piston (corresponding to the "movable part") 52, a second piston 53, a linear motion conversion part 54, an electric motor 55, a first stopper 561, and a second stopper 562.

[0016] The fixed portion 51 is a portion of the drive unit 5 that is fixed to the back plate 4. The fixed portion 51 can also be called a housing for the drive unit 5. More specifically, the fixed portion 51 includes a first cylinder portion 511, a second cylinder portion 512, and a housing portion 513. The first cylinder portion 511 constitutes the vehicle front portion of the fixed portion 51, and is disposed so as to face the first brake shoe 31. The first cylinder portion 511 is formed in a bottomed tubular shape that opens toward the vehicle front. A through hole 511a is formed in the bottom of the first cylinder portion 511, through which the screw shaft 541 of the linear motion conversion portion 54 is inserted.

[0017] The second cylinder portion 512 constitutes the vehicle rear portion of the fixed portion 51, and is disposed so as to face the second brake shoe 32. The second cylinder portion 512 is formed in a cylindrical shape that opens toward the vehicle rear. The second cylinder portion 512 is disposed coaxially with the first cylinder portion 511. In other words, the central axis of the first cylinder portion 511 and the central axis of the second cylinder portion 512 are positioned on the same straight line.

[0018] The accommodation portion 513 is a portion that accommodates the linear motion conversion portion 54 and the load sensor 6, and is located between the first cylinder portion 511 and the second cylinder portion 512. The accommodation portion 513 extends in the left-right direction of the vehicle so as to connect the first cylinder portion 511 and the second cylinder portion 512, which are located on the outer side of the vehicle than the back plate 4, to the electric motor 55, which is located on the inner side of the vehicle than the back plate 4. The accommodation portion 513 is inserted into the through hole 40 of the back plate 4 and fixed to the back plate 4. The torque received by the fixing portion 51 is received by a portion of the back plate 4 that forms the through hole 40. The torque received by the fixing portion 51 may be received by a fastening portion that fastens the fixing portion 51 and the back plate 4.

[0019] The first piston 52 constitutes a movable part that drives the first brake shoe 31 to press it against the rotating drum 2. The first piston 52 is disposed opposite to the upper end of the first brake shoe 31. The first piston 52 is a nut member disposed in the first cylinder portion 511. The first piston 52 is disposed so as to be movable in the front-rear direction relative to the first cylinder portion 511 but unable to rotate. In other words, the first piston 52 and the first cylinder portion 511 are formed with a rotation stop mechanism (e.g., engagement between a rail groove and a rail) (not shown) so as to prevent the first piston 52 from rotating about its axis relative to the first cylinder portion 511.

[0020] The first piston 52 is screwed onto a screw shaft 541 of the linear motion conversion unit 54, and moves back and forth in response to the rotation of the screw shaft 541. That is, when the screw shaft 541 rotates forward, the first piston 52 moves forward (towards the first brake shoe 31), and when the screw shaft 541 rotates reversely, the first piston 52 moves backward.

[0021] The second piston 53 is a piston member that is arranged so as to be movable in the front-rear direction within the second cylinder portion 512. The second piston 53 is arranged to face the upper end portion of the second brake shoe 32.

[0022] The linear motion conversion unit 54 is a mechanism that converts the rotational motion of the output shaft 551 of the electric motor 55 into the linear motion of the first piston 52. The linear motion conversion unit 54 is configured to transmit power from the output shaft 551 to the screw shaft 541 via a reducer. It can be said that the first piston 52 constitutes a part of the linear motion conversion unit 54.

[0023] The electric motor 55 is a drive source of the drive device 5, and is controlled by the brake ECU 7. The drive force of the electric motor 55 is transmitted to the first piston 52 via the output shaft 551 and the linear motion converter .

[0024] The first stopper 561 and the second stopper 562 are separate from the fixed part 51 and are parts that engage with the fixed part 51 in the front-rear direction. The first stopper 561 is a plate-shaped member, and its front surface abuts against a protrusion (inner wall part) 51a formed in the accommodation part 513. The forward movement of the first stopper 561 is restricted by the protrusion 51a.

[0025] The second stopper 562 is a plate-like member, and is disposed rearward of the first stopper 561. The rear surface of the second stopper 562 abuts against a protrusion (inner wall portion) 51b formed in the housing portion 513. The rearward movement of the second stopper 562 is restricted by the protrusion 51b. The load sensor 6 is disposed between the first stopper 561 and the second stopper 562.

[0026] The load sensor 6 is a sensor that is installed on the fixed portion 51 and detects a force (load) applied to the fixed portion 51. The load sensor 6 includes, for example, a strain gauge. The load sensor 6 is sandwiched between a first stopper 561 and a second stopper 562 and detects a force in the front-rear direction (axial direction) received from the first stopper 561 and the second stopper 562. The detection result of the load sensor 6 is transmitted to the brake ECU 7 via a wiring (not shown). In the first embodiment, the load sensor 6 is disposed in the drive device 5, and it can be said that the drive device 5 and the load sensor 6 are one unit. This unit is disposed in an upper portion inside the wheel.

[0027] The brake ECU 7 is an electronic control unit equipped with a processor, a memory, etc. The brake ECU 7 controls the drive device 5 in response to a braking request. When the brake ECU 7 rotates the output shaft 551 of the electric motor 55 in the forward direction in response to the braking request, the first piston 52 advances and presses the first brake shoe 31 against the rotating drum 2. This generates a frictional force (resistance force) against the rotation of the wheel and the rotating drum 2, which becomes a braking force. The brake ECU 7 is equipped with a calculation unit 71 that calculates the braking force based on the detection value of the load sensor 6.

[0028] (Braking while the vehicle is moving) As shown by the arrow in FIG. 1, when braking control is executed during vehicle travel, when the first piston 52 presses the first brake shoe 31 with a force F1, P1, R1, Fc, P2, R2, and F2 are generated at various locations (F1 < F2). The force F2 is the reaction force of the second piston 53 against the second brake shoe 32, and is a value obtained by adding an increment due to frictional force to the force F1.

[0029] The reaction force (=F1) from the first brake shoe 31 against the pressing force F1 of the first piston 52 can be received by the fixing portion 51 and the back plate 4 via the linear motion conversion portion 54, the first stopper 561, the load sensor 6, and the second stopper 562. Also, the force (=F2) with which the second brake shoe 32 presses the second piston 53 can be received by the fixing portion 51 and the back plate 4 via the second piston 53, the second stopper 562, the load sensor 6, and the first stopper 561.

[0030] During braking while traveling, the force F2 is greater than the force F1, and the load sensor 6 is pressed forward with the force F2. The load sensor 6 detects this force (load) and transmits it to the brake ECU 7. Since this force (load) corresponds to the braking force with high accuracy, the brake ECU 7 can calculate the actually generated braking force with high accuracy.

[0031] (Braking in the stopped state) When braking control is executed while the vehicle is stopped, unlike when traveling, the rotating drum 2 is not rotating, so the frictional force due to the rotation of the rotating drum 2 does not occur. Therefore, the forces Fc and F2 become small, the load sensor 6 is pressed backward, and detects a load (reaction force of the first brake shoe 31) corresponding to the force F1 with which the first piston 52 presses the first brake shoe 31. This force (axial force) corresponds to the output of the drive device 5. Therefore, the brake ECU 7 can calculate the output of the drive device 5 based on the detected value of the load sensor 6 during stopping. As a result, for example, calibration of the output of the drive device 5 and detection of the axial force when the parking brake is locked become possible.

[0032] (Effects of the first embodiment) According to the first embodiment, the load sensor 6 is disposed in the drive unit 5 at a fixed portion 51 fixed to the back plate 4. Therefore, the load received by the back plate 4 can be detected with high accuracy. Since the load and the actual braking force correspond with high accuracy, the actual braking force can be calculated with high accuracy. In addition, since the load sensor 6 is provided in the drive unit 5 which is generally installed at the top inside the wheel, it is possible to suppress the complication of wiring. In addition, it is possible to unitize the drive unit 5 and the load sensor 6, which makes it possible to simplify the wiring and improve the ease of assembly.

[0033] <Second embodiment> The vehicle braking device 1A of the second embodiment is different from the first embodiment mainly in the arrangement position of the load sensor 6. The differences will be described below. In the description of the second embodiment, the description and drawings of the first embodiment can be referred to as appropriate.

[0034] As shown in FIG. 3, the load sensor 6 of the second embodiment is disposed in the through hole 40 of the back plate 4, sandwiched between the back plate 4 and the fixed portion 51 (accommodating portion 513). To explain an example of fixing, a fixed member 61 is disposed between the back plate 4 and the load sensor 6. A pin member 62 extending in the front-rear direction is fixed to the outer wall of the fixed portion 51 through the fixed member 61. As a result, the fixed member 61 is fixed to the fixed portion 51, and the load sensor 6 is fixed between the fixed member 61 and the fixed portion 51. In addition, a pin member 63 extending in the left-right direction is fixed to the back plate 4 through the fixed member 61. As a result, the fixed member 61 is fixed to the back plate 4.

[0035] In the second embodiment, there is no second piston 53, and the rear end portion of the fixed portion 51 facing the first piston 52 (a portion corresponding to the second cylinder portion 512) is formed in a solid columnar (rod-like) shape. The rear end portion of the fixed portion 51 is disposed opposite the second brake shoe 32.

[0036] In the second embodiment, when braking control is executed while traveling, the rear end of the fixed portion 51 is pressed by a pressing force (=F2) from the second brake shoe 32, similar to the first embodiment. This pressing force is received by the back plate 4 via the fixed portion 51 and the load sensor 6. At this time, the load sensor 6 receives a forward pressing force (due to elastic deformation) from the fixed portion 51 and detects the load. This load corresponds to the actual braking force with high accuracy, similar to the first embodiment. The brake ECU 7 can calculate the actual braking force based on the detection value of the load sensor 6.

[0037] In the second embodiment, the load sensor 6 is also disposed on the fixed portion 51 of the drive unit 5 located at the upper portion inside the wheel, so that the wiring can be prevented from becoming complicated. Also, the drive unit 5 and the load sensor 6 can be unitized. In this way, the second embodiment also achieves the same effects as the first embodiment. However, with the configuration of the second embodiment, it is difficult to detect the axial force during braking when the vehicle is stopped.

[0038] <Third embodiment> The vehicle braking device 1B of the third embodiment differs from the first embodiment in that the driving force of the electric motor 55 is converted by the linear motion conversion unit 54 and transmitted to the second piston 53 as well. The differences will be described below. In the description of the third embodiment, the description and drawings of the first embodiment can be referred to as appropriate.

[0039] As shown in Fig. 4 and Fig. 5, in the third embodiment, a threaded shaft 542, which is a part of the linear motion conversion unit 54, is disposed behind the threaded shaft 541 via the load sensor 6. The threaded shaft 542 is inserted into a through hole 512a formed in the bottom surface of the second cylinder unit 512. The second cylinder unit 512 is formed in a bottomed cylindrical shape that opens to the rear. The threaded shafts 541, 542 are configured such that the first piston 52 moves forward and the second piston 53 moves backward when the electric motor 55 rotates in the forward direction.

[0040] The load sensor 6 is disposed between the screw shaft 541 and the screw shaft 542 in the accommodation portion 513. The first stopper 561 is disposed between the load sensor 6 and the screw shaft 541. The second stopper 562 is disposed between the load sensor 6 and the screw shaft 542. As in the first embodiment, the first stopper 561 is restricted from moving forward by the fixed portion 51, and the second stopper 562 is restricted from moving backward by the fixed portion 51.

[0041] Even with the configuration of the third embodiment, the pressing force of the second brake shoe 32 due to braking during traveling is received by the fixed part 51 and the back plate 4 via the second piston 53, the screw shaft 542, the second stopper 562, the load sensor 6, and the first stopper 561. At this time, the load sensor 6 detects the forward pressing force from the second stopper 562. This force corresponds to the actual braking force with high accuracy, and the brake ECU 7 can calculate the actual braking force with high accuracy. In addition, the braking force in a stopped state can be calculated in the same way as in the first embodiment. In addition, since the load sensor 6 is arranged in the drive device 5, the complexity of wiring can be suppressed. In addition, the drive device 5 and the load sensor 6 can be unitized.

[0042] <Other> The present invention is not limited to the above embodiment. For example, the number of brake shoes does not need to be two as in the above embodiment, and may be one (for example, an annular brake shoe). In addition, the drive device 5 is not limited to an EMB, and may be, for example, a hydraulic drive device that drives a movable part (piston) with hydraulic pressure. [Explanation of symbols]

[0043] 1, 1A, 1B...vehicle braking device, 2...rotating drum (brake rotor), 31...first brake shoe (first friction member), 32...second brake shoe (second friction member), 33...adjuster, 4...back plate (torque receiving portion), 5...driving device, 51...fixed portion, 52...first piston (movable portion), 6...load sensor, 71...calculation portion.

Claims

1. A brake rotor that rotates together with the wheel; a friction member that is pressed against the brake rotor during braking; a torque receiving portion that applies a braking force to the wheel by preventing rotation of the friction member; a drive device including a fixed portion that houses a linear motion conversion portion and is fixed to the torque receiving portion, and a movable portion that drives the friction member and presses it against the brake rotor; A load sensor is installed on the fixed portion and detects a force applied to the fixed portion; a calculation unit that calculates the braking force based on a detection value of the one of the load sensors; Equipped with The friction member includes a first friction member and a second friction member, A vehicle brake device, wherein the first friction member and the second friction member are connected by an adjuster that is displaceable relative to the torque receiving portion.

2. A brake rotor that rotates together with the wheel; a friction member that is pressed against the brake rotor during braking; a torque receiving portion that applies a braking force to the wheel by preventing rotation of the friction member; a drive device including a fixed portion that houses a linear motion conversion portion and is fixed to the torque receiving portion, and a movable portion that drives the friction member and presses it against the brake rotor; A load sensor is installed on the fixed portion and detects a force applied to the fixed portion; a calculation unit that calculates the braking force based on a detection value of the one of the load sensors; Equipped with the fixing portion is inserted into a through hole of the torque receiving portion and fixed to the torque receiving portion, the load sensor is disposed in the through hole of the torque receiving portion, sandwiched between the torque receiving portion and the fixed portion, and fixed to the fixed portion by a fixing member, The friction member includes a first friction member and a second friction member, A vehicle brake device, wherein the first friction member and the second friction member are connected by an adjuster that is displaceable relative to the torque receiving portion.

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