JP2022138691A - Vehicular brake device - Google Patents

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

The present invention relates to a vehicle braking system.

2. Description of the Related Art As a braking device for a vehicle, for example, one using a drum brake is known as disclosed in Japanese Patent Application Laid-Open No. 2002-67914. In this vehicle braking device, the anchor body is provided with a load sensor in order to calculate the braking force. According to this configuration, it is possible to accurately calculate the actual braking force by detecting the contact load between the brake shoe and the anchor body.

JP-A-2002-67914

In the vehicle braking device described above, the anchor body is arranged at the lower portion within the wheel due to its configuration. Therefore, the load sensor installed in the anchor body is also arranged in the lower part inside the wheel. In this arrangement, the wiring of the load sensor must be routed across the wheel, and the routing of wiring passing between movable parts such as hubs, brake shoes, and arms tends to be complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicular braking device capable of suppressing complication of wiring without lowering detection accuracy of braking force.

A vehicle braking device according to the present invention includes a brake rotator that rotates together with a wheel, a friction member that is pressed against the brake rotator during braking, and a braking force applied to the wheel by preventing rotation of the friction member. a driving device having a torque receiving portion, a fixed portion fixed to the torque receiving portion, and a movable portion for driving the friction member to press against the brake rotor; A load sensor that detects an applied force, and a calculator that calculates the braking force based on a detected value of the load sensor.

According to the present invention, the load sensor is arranged in the fixed portion fixed to the torque receiving portion of the drive device. Therefore, it is possible to accurately detect the load received by the torque receiving portion. 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 generally provided in the driving device that is installed in the upper part of the wheel, it is possible to suppress the complication of wiring.

1 is a configuration diagram (sectional view seen from the left side of a vehicle) of a vehicle braking device according to a first embodiment; FIG. 1 is a configuration diagram (a cross-sectional view as seen from above the vehicle) of a vehicle braking device according to a first embodiment; FIG. FIG. 7 is a configuration diagram (sectional view seen from above the vehicle) of a vehicle braking device according to a second embodiment; FIG. 11 is a configuration diagram (sectional view seen from the left side of the vehicle) of the vehicle braking device of the third embodiment; FIG. 11 is a configuration diagram (cross-sectional view seen from above the vehicle) of a vehicle braking device according to a third embodiment;

An embodiment of the present invention will be described below with reference to the drawings. In addition, in each of the following embodiments, the same reference numerals are given to the parts that are the same or equivalent to each other. Moreover, each figure used for description is a conceptual diagram. In the following description, the front of the vehicle will be referred to as the front, and the rear of the vehicle will be referred to as the rear.

<First embodiment>
As shown in FIGS. 1 and 2, the vehicle braking system 1 of the first embodiment is a duo-servo type drum brake, comprising a rotating drum (corresponding to a "brake rotating body") 2 and a first brake. A shoe (corresponding to a "first friction member") 31, a second brake shoe (corresponding to a "second friction member") 32, an adjuster 33, a back plate 4 constituting a torque receiving portion, and a driving device. 5, a load sensor 6, and a brake ECU 7.

The rotating drum 2 is a member that rotates together with the wheels. 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 arc-shaped members each having a lining 30 on the outer peripheral side. The first brake shoe 31 is a leading shoe arranged relatively forward. The second brake shoe 32 is a trailing shoe arranged relatively rearward. The first brake shoe 31 and the second brake shoe 32 are arranged in an arc shape.

The first brake shoe 31 and the second brake shoe 32 are provided on the back plate 4 so as to be mutually spreadable by a shoe hold pin (not shown). The first brake shoe 31 and the second brake shoe 32 are connected by a return spring (not shown) and configured to return to the initial position when no force is applied.

The adjuster 33 is a member that transmits force from one end to the other end, and is a bar-shaped member whose length can be adjusted. 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 is not in contact with the back plate 4 and is movable with respect to the back plate 4 . Thus, the first brake shoe 31 and the second brake shoe 32 are connected by the adjuster 33 that is displaceable with respect to the back plate 4 .

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 braking force to the wheels by preventing rotation of the first brake shoe 31 and the second brake shoe 32 . A driving device 5 is fixed to the back plate 4 .

The driving device 5 is an actuator that drives the first brake shoe 31 . The driving device 5 of the first embodiment constitutes an electric mechanical brake (EMB) that drives the first piston 52 with an electric motor 55 . The driving device 5 is arranged between the upper end of the first brake shoe 31 and the upper end of the second brake shoe 32 . The driving device 5 includes a fixed portion 51, a first piston (corresponding to a “movable portion”) 52, a second piston 53, a linear motion conversion portion 54, an electric motor 55, a first stopper 561, and a 2 stoppers 562 and .

The fixed portion 51 is a portion of the driving device 5 that is fixed to the back plate 4 . The fixed portion 51 can also be said to be a housing of the driving device 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 a vehicle front portion of the fixing portion 51 and is arranged to face the first brake shoe 31 . The first cylinder portion 511 is formed in a bottomed tubular shape that opens forward of the vehicle. A through-hole 511 a through which the screw shaft 541 of the direct-acting converting portion 54 is inserted is formed in the bottom portion of the first cylinder portion 511 .

The second cylinder portion 512 constitutes the vehicle rear portion of the fixed portion 51 and is arranged so as to face the second brake shoe 32 . The second cylinder portion 512 is formed in a tubular shape that opens rearward of the vehicle. The second cylinder portion 512 is arranged coaxially with the first cylinder portion 511 . That is, 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.

The accommodation portion 513 is a portion that accommodates the direct-acting conversion portion 54 and the load sensor 6 and is positioned between the first cylinder portion 511 and the second cylinder portion 512 . The housing portion 513 is arranged on the left and right sides of the vehicle so as to connect the first cylinder portion 511 and the second cylinder portion 512 positioned on the vehicle outer side of the back plate 4 and the electric motor 55 positioned on the vehicle inner side of the back plate 4 . extending in the direction The accommodating portion 513 is inserted through 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 the portion of the back plate 4 where the through hole 40 is formed. The torque received by the fixed portion 51 may be received by a fastening portion that fastens the fixed portion 51 and the back plate 4 .

The first piston 52 constitutes a movable portion that drives the first brake shoe 31 and presses it against the rotating drum 2 . The first piston 52 is arranged to face the upper end of the first brake shoe 31 . The first piston 52 is a nut member arranged inside the first cylinder portion 511 . The first piston 52 is arranged so as to be movable in the front-rear direction and unrotatable with respect to the first cylinder portion 511 . That is, the first piston 52 and the first cylinder portion 511 are provided with a rotation stop mechanism (not shown) (for example, a rail groove and a rail) so that the first piston 52 does not rotate about the axis with respect to the first cylinder portion 511. engagement) is formed.

The first piston 52 is screwed onto the threaded shaft 541 of the direct motion converter 54 and moves back and forth as the threaded shaft 541 rotates. That is, when the screw shaft 541 rotates forward, the first piston 52 moves forward (toward the first brake shoe 31), and when the screw shaft 541 rotates backward, the first piston 52 moves rearward.

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

The linear motion converter 54 is a mechanism that converts the rotary motion of the output shaft 551 of the electric motor 55 into the linear motion of the first piston 52 . The direct-acting converting portion 54 is configured to transmit power from the output shaft 551 to the screw shaft 541 via the reduction gear. It can be said that the first piston 52 constitutes a part of the direct-acting converter 54 .

The electric motor 55 is a drive source for the drive device 5 and is controlled by the brake ECU 7 . The driving force of the electric motor 55 is transmitted to the first piston 52 via the output shaft 551 and the direct-acting converter 54 .

The first stopper 561 and the second stopper 562 are separate from the fixing portion 51 and are portions that engage with the fixing portion 51 in the front-rear direction. The first stopper 561 is a plate-like member whose front surface is in contact with a projection (inner wall portion) 51 a formed inside the housing portion 513 . The forward movement of the first stopper 561 is restricted by the projection 51a.

The second stopper 562 is a plate-like member and is arranged behind the first stopper 561 . A rear surface of the second stopper 562 abuts on a projection (inner wall portion) 51 b formed inside the housing portion 513 . The rearward movement of the second stopper 562 is restricted by the projection 51b. A load sensor 6 is arranged between the first stopper 561 and the second stopper 562 .

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 has, for example, a strain gauge. The load sensor 6 is sandwiched between the first stopper 561 and the second stopper 562 and detects the force in the longitudinal direction (axial direction) received from the first stopper 561 and the second stopper 562 . A detection result of the load sensor 6 is transmitted to the brake ECU 7 via wiring (not shown). In 1st Embodiment, the load sensor 6 is arrange|positioned 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 located in the upper part within the wheel.

The brake ECU 7 is an electronic control unit including a processor, memory, and the like. Brake ECU7 controls the drive device 5 according to a braking request. When the brake ECU 7 forwardly rotates the output shaft 551 of the electric motor 55 in response to a braking request, the first piston 52 advances and presses the first brake shoe 31 against the rotating drum 2 . As a result, a frictional force (resistive force) is generated against the rotation of the wheels and the rotating drum 2, and serves as a braking force. The brake ECU 7 includes a calculator 71 that calculates the braking force based on the detected value of the load sensor 6 .

(Braking while the vehicle is running)
As shown by the arrows in FIG. 1, when braking control is executed while the vehicle is running, force F1 with which the first piston 52 presses the first brake shoe 31 causes pressures P1, R1, Fc, P2, R2, and F2 at various locations. occurs (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 increase due to the frictional force to the force F1.

A reaction force (=F1) from the first brake shoe 31 against the pressing force F1 of the first piston 52 is applied to the fixed portion 51 via the direct-acting converting portion 54, the first stopper 561, the load sensor 6, and the second stopper 562. and the backplate 4 can receive. Further, the force (=F2) with which the second brake shoe 32 presses the second piston 53 is transmitted through the second piston 53, the second stopper 562, the load sensor 6, and the first stopper 561 to the fixed portion 51 and the back plate. 4 can be received.

In braking during running, the force F2 is greater than the force F1, and the load sensor 6 is pushed forward by the force F2. The load sensor 6 detects this force (load) and transmits it to the brake ECU 7 . Since this force corresponds to the braking force with high accuracy, the brake ECU 7 can calculate the braking force actually generated with high accuracy.

(Braking in Stopped State)
When the braking control is executed while the vehicle is stopped, the rotating drum 2 does not rotate unlike when the vehicle is running. As a result, the forces Fc and F2 become smaller, the load sensor 6 is pushed rearward, and the load corresponding to the force F1 with which the first piston 52 presses the first brake shoe 31 (the reaction force of the first brake shoe 31). to detect This force (axial force) corresponds to the output of the driving device 5 . Therefore, the brake ECU 7 can calculate the output of the driving device 5 based on the detection value of the load sensor 6 while the vehicle is stopped. As a result, for example, it is possible to calibrate the output of the driving device 5 and detect the axial force when the parking brake is locked.

(Effect of the first embodiment)
According to the first embodiment, the load sensor 6 is arranged in the drive device 5 on a fixed part 51 fixed to the back plate 4 . Therefore, the load applied to 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 generally provided in the driving device 5 that is installed in the upper part of the wheel, it is possible to suppress the complication of wiring. In addition, the driving device 5 and the load sensor 6 can be unitized, so wiring can be simplified and assembly workability can be improved.

<Second embodiment>
A vehicle braking system 1A of the second embodiment differs from the first embodiment mainly in the arrangement position of the load sensor 6. As shown in FIG. The different points 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.

As shown in FIG. 3, the load sensor 6 of the second embodiment is arranged in the through hole 40 of the back plate 4 so as to be sandwiched between the back plate 4 and the fixing portion 51 (accommodating portion 513). To explain an example of fixing, a fixing member 61 is arranged between the back plate 4 and the load sensor 6 . A pin member 62 extending in the front-rear direction penetrates through the fixing member 61 and is fixed to the outer wall of the fixing portion 51 . As a result, the fixing member 61 is fixed to the fixing portion 51 , and the load sensor 6 is fixed by being sandwiched between the fixing member 61 and the fixing portion 51 . A pin member 63 extending in the left-right direction penetrates through the fixing member 61 and is fixed to the back plate 4 . Thereby, the fixing member 61 is fixed to the back plate 4 .

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 (the portion corresponding to the second cylinder portion 512) is formed in a solid columnar shape (rod shape). there is A rear end portion of the fixing portion 51 is arranged to face the second brake shoe 32 .

In the second embodiment, when braking control is executed during running, the rear end portion of the fixed portion 51 is pressed by the second brake shoe 32 with a pressing force (=F2), as in the first embodiment. This pressing force is received by the back plate 4 via the fixing 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 fixing portion 51 and detects the load. This load corresponds to the actual braking force with high precision, as in the first embodiment. The brake ECU 7 can calculate the actual braking force based on the detected value of the load sensor 6 .

Also according to the second embodiment, since the load sensor 6 is arranged on the fixing portion 51 of the driving device 5 positioned at the upper part in the wheel, the complication of wiring can be suppressed. Also, the driving device 5 and the load sensor 6 can be unitized. Thus, the second embodiment also exhibits the same effect as the first embodiment. In the configuration of the second embodiment, it is difficult to detect the axial force during braking while the vehicle is stopped.

<Third Embodiment>
The vehicle braking system 1B of the third embodiment differs from the first embodiment in that the driving force of the electric motor 55 is converted by the direct-acting converter 54 and transmitted to the second piston 53 as well. there is The different points 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.

As shown in FIGS. 4 and 5, in the third embodiment, a threaded shaft 542 that is a part of the direct-acting converter 54 is arranged behind the threaded shaft 541 with the load sensor 6 interposed therebetween. The screw shaft 542 is inserted through a through hole 512 a formed in the bottom surface of the second cylinder portion 512 . The second cylinder portion 512 is formed in a bottomed tubular shape that is open rearward. The screw shafts 541 and 542 are configured so that forward rotation of the electric motor 55 causes the first piston 52 to move forward and the second piston 53 to move backward.

The load sensor 6 is arranged between the screw shaft 541 and the screw shaft 542 inside the housing portion 513 . The first stopper 561 is arranged between the load sensor 6 and the screw shaft 541 . The second stopper 562 is arranged 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 fixing portion 51 , and the second stopper 562 is restricted from moving backward by the fixing portion 51 .

Even with the configuration of the third embodiment, the pressing force of the second brake shoe 32 is applied through the second piston 53, the screw shaft 542, the second stopper 562, the load sensor 6, and the first stopper 561 by braking during running. The fixed portion 51 and the back plate 4 receive the same. 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. Also, the braking force in the stopped state can be calculated in the same manner as in the first embodiment. In addition, since the load sensor 6 is arranged inside the driving device 5, it is possible to suppress complication of wiring. Also, the driving device 5 and the load sensor 6 can be unitized.

<Others>
The present invention is not limited to the above embodiments. For example, the number of brake shoes may not be two as in the above embodiment, but may be one (for example, an annular brake shoe). Further, the driving device 5 is not limited to the EMB, and may be, for example, a hydraulic driving device that hydraulically drives a movable portion (piston).

DESCRIPTION OF SYMBOLS 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 part), 5... Driving device, 51... Fixed part, 52... First piston (movable part), 6... Load sensor, 71... Calculating part.

Claims (2)

a brake rotor that rotates with the wheel;
a friction member 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 driving device having a fixed portion 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 installed on the fixed part for detecting a force applied to the fixed part;
a calculation unit that calculates the braking force based on the detected value of the load sensor;
A vehicle braking device. The friction member comprises a first friction member and a second friction member,
2. The vehicle braking device according to claim 1, wherein said first friction member and said second friction member are connected by an adjuster displaceable with respect to said torque receiving portion.

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