KR20240067437A - Brake apparutus and controlling method thereof - Google Patents

Abstract

A vehicle brake device includes: a pair of brake shoes provided inside a drum that rotates together with a wheel of the vehicle; a spindle and nut provided between the pair of brake shoes; a drive motor configured to rotate the spindle; a temperature sensor that outputs a signal corresponding to the temperature of the brake device; and a processor that controls the driving motor. The processor, in response to receiving a brake release request, operates the drive motor to space the pair of brake shoes from the drum, and based on the drive voltage of the drive motor and the output signal of the temperature sensor, The drive motor can be stopped from running.

Description

Brake device and its control method {BRAKE APPARUTUS AND CONTROLLING METHOD THEREOF}

The disclosed invention relates to a brake device and a control method thereof that can accurately identify the position of a brake shoe by compensating for temperature changes.

Vehicles are essentially equipped with a brake device to perform braking, and various types of brake devices have been proposed for the safety of users and passengers.

In general, brake devices can be divided into caliper-type brakes and drum-type brakes (hereinafter referred to as 'drum brakes').

This drum brake has a structure in which a pair of brake shoes provided inside a drum that rotates together with the wheel are expanded by an electric actuator to brake the rotation of the drum.

In existing drum brakes, a self-adjuster is provided to adjust the clearance between the drum and the brake lining due to wear of the brake lining. Due to the expansion of the automatic adjuster in a high temperature environment, brake drag may occur while the vehicle is driving. To prevent this, a thermo-clip may be provided to limit movement of the automatic regulator at high temperatures.

One aspect of the disclosed invention seeks to provide a brake device and a control method that can accurately identify the position of a brake shoe by compensating for temperature changes without an automatic regulator or thermoclip.

One aspect of the disclosed invention provides a brake device and a control method thereof that can accurately identify the position of the brake shoe without a position detection sensor (e.g., Hall sensor, etc.) of the drive motor.

A vehicle brake device according to one aspect of the disclosed invention includes a pair of brake shoes provided inside a drum that rotates together with a wheel of the vehicle; a spindle and nut provided between the pair of brake shoes; a drive motor configured to rotate the spindle; a temperature sensor that outputs a signal corresponding to the temperature of the brake device; and a processor that controls the driving motor. The processor, in response to receiving a brake release request, operates the drive motor to space the pair of brake shoes from the drum, and adjusts the driving voltage of the drive motor, the drive current of the drive motor, and the temperature sensor. Based on the output signal, operation of the drive motor can be stopped.

The processor estimates a center gap between the pair of brake shoes and the drum based on the drive voltage of the drive motor, the drive current of the drive motor, and the output signal of the temperature sensor, and the estimated center gap Based on this target center clearance, the drive motor can be stopped from operating.

The processor may estimate the rotational speed of the driving motor based on the driving voltage of the driving motor and the driving current of the driving motor, and may compensate for the rotational speed of the driving motor based on the output signal of the temperature sensor. .

The processor estimates the moving distance of each of the pair of brake shoes based on the compensated rotation speed, and determines the distance between the pair of brake shoes and the drum based on the moving distance of each of the pair of brake shoes. The center gap can be estimated.

The processor may continue to operate the drive motor based on the estimated center clearance being no more than the target center clearance.

The processor, in response to receiving a brake engagement request, operates the drive motor so that the pair of brake shoes approaches the drum, and determines that a drive current of the drive motor is greater than or equal to the first reference current while engaging the brake. Based on this, it is possible to stop operating the drive motor.

The processor identifies whether the time elapsed since the driving current became less than the second reference current is greater than or equal to the reference time, based on the fact that the driving current is less than or equal to the second reference current while releasing the brake, and the elapsed time Based on this being more than the reference time, the center clearance between the pair of brake shoes and the drum can be estimated, and the operation of the drive motor can be stopped based on the estimated center clearance being more than the target center clearance. .

According to one aspect of the disclosed invention, a pair of brake shoes provided inside a drum that rotates with the wheel of a vehicle, a spindle and nut provided between the pair of brake shoes, and configured to rotate the spindle. A control method of a brake device including a drive motor includes, in response to receiving a brake release request, operating the drive motor so that the pair of brake shoes are spaced apart from the drum; It may include stopping operation of the drive motor based on the driving voltage of the drive motor, the drive current of the drive motor, and the temperature of the brake device.

Stopping the driving motor includes estimating the center gap between the pair of brake shoes and the drum based on the driving voltage of the driving motor, the driving current of the driving motor and the temperature of the brake device; , and may include stopping operation of the drive motor based on the estimated center gap being greater than or equal to the target center gap.

Estimating the center gap between the pair of brake shoes and the drum includes estimating the rotation speed of the drive motor based on the drive voltage of the drive motor and the drive current of the drive motor, and the temperature of the brake device. It may further include compensating the rotational speed of the driving motor based on the rotation speed of the driving motor.

Estimating the center gap between the pair of brake shoes and the drum includes estimating the moving distance of each of the pair of brake shoes based on the compensated rotation speed, and estimating the moving distance of each of the pair of brake shoes It may further include estimating a center gap between the pair of brake shoes and the drum based on .

The control method may further include continuing to operate the drive motor based on the estimated center gap not being equal to or greater than the target center gap.

The control method, in response to receiving a brake engagement request, operates the drive motor so that the pair of brake shoes approaches the drum, and, while engaging the brake, the drive current of the drive motor is equal to or greater than a first reference current. Based on this, it may further include stopping operation of the drive motor.

Stopping operating the drive motor determines whether the time elapsed after the drive current becomes less than the second reference current is greater than or equal to the reference time, based on the drive current being less than or equal to the second reference current while releasing the brake. identify, estimate a center gap between the pair of brake shoes and the drum based on the elapsed time being greater than or equal to the reference time, and operate the drive motor based on the estimated center gap being greater than or equal to the target center gap. This may include stopping operation.

According to one aspect of the disclosed invention, a brake device and a control method thereof that can accurately identify the position of a brake shoe by compensating for temperature changes without an automatic adjuster and a thermoclip can be provided. Thereby, brake drag caused by the automatic adjuster is prevented while the vehicle is running, and constant hydraulic braking performance can be provided.

According to one aspect of the disclosed invention, a brake device that can accurately identify the position of a brake shoe without a position detection sensor (for example, a Hall sensor, etc.) of a drive motor and a control method thereof can be provided.

1 shows a front view of a drum brake according to one embodiment.
Figure 2 shows a partially cut away perspective view of a drum brake according to one embodiment.
Figure 3 shows an example of how a drum brake operates according to an embodiment.
Figure 4 shows a control configuration of a drum brake according to one embodiment.
Figure 5 shows a functional block of a control unit included in a drum brake according to an embodiment.
Figure 6 shows a diagram for explaining the center gap between the drum and the lining of a drum brake according to one embodiment.
Figure 7 shows a fastening operation of a drum brake according to one embodiment.
Figure 8 shows a drum brake release operation according to one embodiment.

Like reference numerals refer to like elements throughout the specification. This specification does not describe all elements of the embodiments, and general content or overlapping content between the embodiments in the technical field to which the disclosed invention pertains is omitted. The term 'part, module, member, block' used in the specification may be implemented as software or hardware, and depending on the embodiment, a plurality of 'part, module, member, block' may be implemented as a single component, or It is also possible for one 'part, module, member, or block' to include multiple components.

Throughout the specification, when a part is said to be “connected” to another part, this includes not only direct connection but also indirect connection, and indirect connection includes connection through a wireless communication network. do.

Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Throughout the specification, when a member is said to be located “on” another member, this includes not only cases where a member is in contact with another member, but also cases where another member exists between the two members.

Terms such as first and second are used to distinguish one component from another component, and the components are not limited by the above-mentioned terms.

Singular expressions include plural expressions unless the context clearly makes an exception.

The identification code for each step is used for convenience of explanation. The identification code does not explain the order of each step, and each step may be performed differently from the specified order unless a specific order is clearly stated in the context. there is.

Hereinafter, the operating principle and embodiments of the disclosed invention will be described with reference to the attached drawings.

1 shows a front view of a drum brake according to one embodiment. Figure 2 shows a partially cut away perspective view of a drum brake according to one embodiment. Figure 3 shows an example of how a drum brake operates according to an embodiment.

Referring to FIGS. 1, 2, and 3, the drum brake 1 includes a pair of brake shoes 11 and 12 respectively disposed on both sides of the inside of a drum (not shown) that rotates with the wheel of the vehicle, and an electric It may include a power conversion unit 200 that receives rotational force from the actuator 100 and the electric actuator 100 to pressurize or depressurize the pair of brake shoes 11 and 12.

A pair of brake shoes 11 and 12 is mounted on the back plate 10 coupled to the vehicle body so as to operate outward and comes into close contact with the inner peripheral surface of the drum to generate braking force.

A pair of brake shoes (11, 12) is provided in an arc shape, supported by an anchor block (20) at the bottom, and a first brake shoe (11) disposed on the forward rotation direction side of the drum with the anchor block (20) as the center. and a second brake shoe 12 disposed on the opposite side. The first and second brake shoes 11 and 12 are coupled to the semicircular rims 11a and 12a to which the linings 11b and 12b are attached, respectively, and the inner peripheral surfaces of the rims 11a and 12a to form the rims 11a and 12a. It includes webs 11c and 12c that support.

An anchor block is provided between one end of the web (11c) of the first brake shoe (11) and one end of the web (12c) of the second brake shoe (12) to prevent the pair of brake shoes (11, 12) from being separated during braking. (20) is provided, and between the other end of the web (11c) of the first brake shoe (11) and the other end of the web (12c) of the second brake shoe (12), the two brake shoes (11, 12) are operated outward to form a lining ( A wheel cylinder 30 is installed so that 11b, 12b) are in close contact with the drum to generate braking force.

Therefore, when the braking hydraulic pressure is transmitted to the wheel cylinder 30, the piston built in the wheel cylinder 30 advances outward, and accordingly, the other end of the pair of brake shoes 11 and 12 is pushed outward, while one end is pushed outward. As it rotates around the anchor block 20, it rubs against the inner peripheral surface of the drum to generate braking force.

Meanwhile, the unexplained reference numeral '40' is a return spring that allows the two brake shoes 11 and 12 to return to their original state after braking.

The electric actuator 100 includes a drive motor 110 and a reduction gear unit 120.

The drive motor 110 is coupled to the back plate 10. The drive motor 110 is disposed at the rear of the back plate 10, and a portion protrudes toward the front of the back plate 10 where the two brake shoes 11 and 12 are disposed. A portion of the drive motor 110 protruding forward of the back plate 10 may be coupled to the support plate 230 supporting the power conversion unit 200.

The drive motor 110 may be a known electric motor capable of rotating forward/reverse depending on the flow direction of the applied current. The driving motor 110 is provided with a rotation shaft 111, and the first worm gear 121 of the reduction gear unit 120 may be coupled to the rotation shaft 111. The drive motor 110 is electrically connected to the control unit so that its operation can be electrically controlled. For example, the control unit may control motor operations such as driving and stopping, forward rotation and reverse rotation of the driving motor 110.

The reduction gear unit 120 includes a first worm gear 121 coupled to the rotation shaft 111 of the drive motor 110, a first worm wheel 122 meshed with the first worm gear 121, and one end It is installed to penetrate the first worm wheel 122 and includes a worm shaft 123 having a second worm gear 124 at the other end, and a second worm wheel 125 engaged with the second worm gear 124.

The second worm wheel 125 engages with the second worm gear 124 and rotates. This second worm wheel 125 may be provided on the spindle member 210 of the power conversion unit 200. The second worm wheel 125 may be coupled to the spindle member 210 and rotated together with the spindle member 210. The driving force amplified from the reduction gear unit 120 is transmitted to the power conversion unit 200.

The power conversion unit 200 converts the rotational force transmitted from the reduction gear unit 120 into linear motion and serves to press the pair of brake shoes 11 and 12 toward the inner surface of the drum. More specifically, the power conversion unit 200 includes a spindle member 210, a nut member 220 screwed to the spindle member 210, and a support plate 230 that guides the movement of the nut member 220. .

The spindle member 210 has a predetermined length and is arranged perpendicular to the worm shaft 123. The spindle member 210 is provided with a second worm wheel 125 coupled to its center so that it can rotate together with the second worm wheel 125. The spindle member 210 has a first screw shaft 211 formed on one side with respect to the second worm wheel 125, and a second screw shaft 212 formed on the other side. At this time, the first screw shaft 211 and the second screw shaft 212 are provided to have threads in opposite directions. For example, a left-hand thread may be formed on the first screw shaft 211, and a right-hand thread may be formed on the second screw shaft 212.

The nut member 220 is coupled to both ends of the spindle member 210 in the longitudinal direction. The nut member 220 serves to press the two brake shoes 11 and 12 toward the inner surface of the drum. This nut member 220 includes a first nut 221 screw-coupled with the first screw shaft 211 provided on one side of the spindle member 210, and a second screw shaft 212 provided on the other side of the spindle member 210. It may be composed of a second nut 222 that is screwed together.

The first nut 221 has a thread formed on its inner peripheral surface to be screwed to the spindle member 210, and a first support portion 223 is formed at its end. Accordingly, in a state in which the first nut 221 is screwed to the first screw shaft 211, the first support portion 223 is supported on the web 11c of the first brake shoe 11.

The second nut 222 has a thread formed on its inner peripheral surface to be screwed to the spindle member 210, and a second support shaft 224 is formed at its end. Accordingly, while the second nut 222 is screwed to the second screw shaft 212, the second support portion 224 is supported on the web 12c of the second brake shoe 12.

The first and second support parts 223 and 224 may be provided in a so-called 'ㄷ' shape to be stably supported on the webs 11c and 12c, respectively. Accordingly, the webs 11c and 12c are inserted into the first and second support portions 223 and 224 and are stably supported. Therefore, when the spindle member 210 rotates, the first nut 221 and the second nut 222 are limited in rotation by the webs 11c and 12c, so that they move along the longitudinal direction of the spindle member 210. It moves in a straight line and pressurizes or depressurizes the two brake shoes (11, 12).

Meanwhile, as the first screw shaft 211 and the second screw shaft 212 are threaded in opposite directions, the first nut 221 and the second nut 222 are aligned in the rotation direction of the spindle member 210. Accordingly, they move in a direction away from each other (brake application direction) or in a direction closer to each other (brake release direction).

The support plate 230 is provided to surround the outer peripheral surface of the spindle member 210 and the nut member 220 and is fixed to the back plate 10, and serves to guide the nut member 220 when it moves in a straight line. This support plate 230 is operated by hydraulic pressure and can be formed integrally to form the cylinder body of the wheel cylinder 30 that presses the two brake shoes 11 and 12. A guide hole 232 is formed in this support plate 230 to guide the movement of the first nut 221 and the second nut 222.

Hereinafter, the fastening operation of the drum brake 1 having the above-described configuration will be described.

When the driver operates the parking switch while the two brake shoes 11 and 12 are spaced apart from the inner surface of the drum, the control unit drives the drive motor 110 to rotate the rotation shaft 111 forward to the reduction gear unit 120. Transmits rotational force. The reduction gear unit 120 has the structure of a worm reducer in which the first worm wheel 122 engaged with the first worm gear 121 rotates, and the worm shaft 123 and the worm coupled to the first worm wheel 122 The second worm gear 124 formed on the shaft 123 rotates together and transmits rotational force to the second worm wheel 125. At this time, the second worm wheel 125 is provided to rotate together with the spindle member 210 of the power conversion unit 200, thereby rotating the spindle member 210. That is, as the spindle member 210 rotates, the first nut 221 and the second nut 222, respectively screwed to both sides of the spindle member 210, move linearly and move the two brake shoes 11 and 12 on the drum. Braking is achieved by applying pressure to the inner surface.

Meanwhile, when releasing the fastening, this can be implemented by generating a driving force in the reverse direction of the fastening of the drive motor 110. That is, the rotational force is transmitted in the same way as when fastening, but by rotating in the opposite direction, the first nut 221 and the second nut 222 move to their original positions and the braking force can be released.

Figure 4 shows a control configuration of a drum brake according to one embodiment. Figure 5 shows a functional block of a control unit included in a drum brake according to an embodiment. Figure 6 shows a diagram for explaining the center gap between the drum and the lining of a drum brake according to one embodiment.

Referring to FIGS. 4, 5, and 6, the drum brake 1 includes a drive motor 110, a voltage sensor 310, a current sensor 320, a temperature sensor 330, a drive unit 340, and a control unit 350. ) may include. The components shown in FIG. 4 do not correspond to essential components of the drum brake 1, and at least some of them may be omitted.

The drive motor 110 may be the same as the drive motor 110 described in FIGS. 1, 2, and 3. The driving motor 110 may rotate in the first direction (forward direction) or the second direction (reverse direction) depending on the supplied current. The rotational movement of the driving motor 110 may be converted into linear movement of the first nut 221 and the second nut 222 through the reduction gear unit 120 and the power conversion unit 200. The first nut 221 and the second nut 222 that move linearly can pressurize or release the first and second brake shoes 11 and 12, respectively.

The voltage sensor 310 may measure the driving voltage applied to the driving motor 110 and provide an electrical signal corresponding to the measured driving voltage to the control unit 350.

The voltage sensor 310 may include, for example, a voltage distribution circuit that divides (or reduces) the voltage applied to the driving motor 110 by a predetermined ratio. The voltage distribution circuit may provide the control unit 350 with a voltage divided at a predetermined ratio.

The current sensor 320 may measure the driving current supplied to the driving motor 110 and provide an electrical signal corresponding to the measured driving current to the control unit 350.

The current sensor 320 may include, for example, a shutter resistor that converts the driving current applied to the driving motor 110 into voltage. The shutter resistor may provide a voltage corresponding to the driving current of the driving motor 110 to the control unit 350.

The temperature sensor 330 may measure the temperature of the drum brake 1 and provide an electrical signal corresponding to the measured temperature of the drum brake 1 to the control unit 350.

The temperature sensor 330 may include, for example, a thermistor whose electrical resistance changes depending on temperature. The thermistor may provide a voltage corresponding to temperature to the control unit 350.

The drive unit 340 is electrically provided between the control unit 350 and the drive motor 110, and can control the driving voltage and/or drive current of the drive motor 110 in response to a control signal from the control unit 350. .

The driving unit 340 may include a driving circuit implemented in various topologies depending on the type of the driving motor 110. For example, if the driving motor 110 includes a three-phase motor, the driving unit 340 may include a three-phase inverter circuit. Additionally, if the driving motor 110 includes a single-phase motor, the driving unit 340 may include an H bridge circuit.

The control unit 350 may receive user input from a parking switch or brake pedal provided in the vehicle, and control the operation of the drum brake 1 based on the received user input.

The control unit 350 may include one or two or more semiconductor devices, and may be called variously such as ECU (Electronic Control Unit). The control unit 350 may include, for example, one or two or more processors and/or one or two or more memories.

The control unit 350 includes a processor 351 that provides a control signal for controlling the operation of the drum brake 1 and a memory 352 that stores or memorizes programs and/or data for controlling the operation of the drum brake 1. may include.

The processor 351 may include one or two or more processing elements or one or two or more processing cores, and may be called variously such as MCU (Micro Controller Unit).

The processor 351 may provide a control signal to the driver 340 to control the operation of the drive motor 110 based on the received user input.

For example, the processor 351 sends a first control signal to the drive unit 340 to rotate the drive motor 110 in the first direction (forward direction) based on a user input for fastening the drum brake 1. can be output. Additionally, the processor 351 outputs a second control signal to the drive unit 340 to rotate the drive motor 110 in the second direction (reverse direction) based on a user input for releasing the drum brake 1. can do.

The memory 352 may include one or two or more memory elements or one or two or more registers.

The memory 352 may store or memorize programs and/or data for controlling the operation of the driving motor 110 based on received user input. The memory 352 may provide programs and/or data to the processor 351 and store temporary data generated during the operation of the processor 351.

The memory 352 includes, for example, volatile memory such as Static Random Access Memory (S-RAM) and Dynamic Random Access Memory (D-RAM), Read Only Memory (ROM), It may include non-volatile memory such as Erasable Programmable Read Only Memory (EPROM) and flash memory.

In this way, the control unit 350 can engage or release the drum brake 1 in response to user input.

In addition, the control unit 350 receives at least one output signal from the output signal of the voltage sensor 310, the output signal of the current sensor 320, and/or the output signal of the temperature sensor 330, and responds to the received output signal. Based on this, the positions of the brake shoes 11 and 12 can be identified.

For example, the control unit 350 may include a plurality of functional blocks as shown in FIG. 5 .

The control unit 350 uses a no-load compensation curve 410, a current-voltage converter 420, a first subtractor 430, a motor speed calculator 440, and a first subtractor 430 to identify the positions of the brake shoes 11 and 12. 2 subtractor 441, speed compensation curve 443, first multiplier 445, adder 447, temperature compensation curve 450, second multiplier 460, first operator 470, second operator ( 480), an integrator 490, etc. The components shown in FIG. 5 do not correspond to essential components of the control unit 350, and at least some of them may be omitted.

The no-load compensation curve 410 may receive the driving voltage value measured by the voltage sensor 310 and output a compensation current value for no-load compensation. The compensation current value for no-load compensation depends on the driving voltage of the driving motor 110, and the no-load compensation curve 410 may include a plurality of compensation current values each corresponding to a plurality of driving voltages of the driving motor 110. there is.

The current-voltage converter 420 may receive the compensation current value output from the no-load compensation curve 410 and convert the compensation current value into a compensation voltage value. The conversion ratio of the current-to-voltage converter 420 may correspond to the resistance of the drive motor 110, for example.

The first subtractor 430 may receive the driving voltage value measured by the voltage sensor 310 and the compensation voltage value converted by the current-voltage converter 420, and the difference between the driving voltage value and the compensation voltage value The voltage value corresponding to can be output.

The motor speed calculator 440 may receive the voltage value output from the first subtractor 430 and convert the received voltage value into a motor speed value indicating the motor speed of the driving motor 110. The conversion ratio of the motor speed calculator 440 may correspond to the motor characteristics of the driving motor 110, for example. In other words, the motor speed calculator 440 converts the input voltage value (voltage value corresponding to the sum of the driving voltage value and the compensation voltage value) into the motor speed of the driving motor 110 according to the motor characteristics of the driving motor 110. can do.

The second subtractor 441 receives the driving current value measured by the current sensor 320 and the compensation current value output from the no-load compensation curve 410, and receives the no-load value corresponding to the difference between the driving current value and the compensation current value. The compensated current value can be output.

The speed compensation curve 443 may receive the driving voltage value measured by the voltage sensor 310 and output a current proportional factor for current compensation. The current proportional factor for current compensation depends on the driving voltage of the driving motor 110, and the speed compensation curve 443 may include a plurality of current proportional factors corresponding to a plurality of driving voltage values of the driving motor 110. there is.

The first multiplier 445 receives the compensated current value output from the second subtractor 441 and the current proportional factor output from the speed compensation curve 443, and receives a value corresponding to the product of the compensated current value and the current proportional factor. The first compensation motor speed value can be output.

The adder 447 receives the motor speed value output from the motor speed calculator 440 and the compensation motor speed value output from the first multiplier 445, and corresponds to the sum between the motor speed value and the first compensation motor speed value. The second compensation motor speed value may be output.

The temperature compensation curve 450 may receive the driving current value measured by the temperature sensor 330 and output a temperature proportional factor for temperature compensation. The temperature proportional factor for temperature compensation depends on the temperature of the drum brake 1, and the temperature compensation curve 450 may include a plurality of temperature proportional factors corresponding to a plurality of temperature values of the drum brake 1.

The second multiplier 460 receives the second compensation motor speed value output from the adder 447 and the temperature proportional factor output from the temperature compensation curve 450, and calculates the product between the second compensation motor speed value and the temperature proportional factor. The third compensation motor speed value corresponding to can be output.

The first operator 470 may receive the third compensation motor speed value output from the second multiplier 460 and output a speed value corresponding to the product of the third compensation motor speed value and the first proportional constant. The first proportionality constant may correspond to the gear ratio of the reduction gear unit 120. Accordingly, the first calculator 470 can convert the rotational speed value of the driving motor 110 into the rotational speed value of the reduction gear unit 120.

The second operator 480 may receive the rotational speed value output from the first operator 470 and output a speed value corresponding to the product of the received rotational speed value and the second proportional constant. The second proportionality constant may correspond to the pitch value of the spindle member 210 and the nut member 220 included in the power conversion unit 200. Accordingly, the second calculator 480 can convert the rotational speed value of the reduction gear unit 120 into the moving speed value of the nut member 220.

The integrator 490 may receive the movement speed value output from the second operator 480 and integrate the received movement speed value for each sampling time. The integrator 490 may calculate the displacement of the nut member 220 by integrating the moving speed value of the nut member 220. In other words, the integrator 490 can calculate the distance traveled by the first and second brake shoes 11 and 12.

In this way, the control unit 350 uses the driving voltage applied to the driving motor 110, the driving current supplied to the driving motor 110, and the temperature of the drum brake 1 to connect the first and second brake shoes 11. , 12) can calculate the distance moved by the rotation of the drive motor 110.

As a result, a Hall sensor for detecting the rotor position of the drive motor 110 can be omitted, and an automatic adjuster and thermo clip for compensating for errors due to the temperature of the drum brake 1 can be omitted. there is.

The control unit 350 controls the distance between the centers of the linings 11b and 12b and the center of the drum 50 based on the distance moved by the first and second brake shoes 11 and 12 by the spindle-nuts 210 and 220. The gap (hereinafter referred to as 'center gap') can be calculated.

For example, the control unit 350 controls the center of the linings 11b and 12b and the drum 50 based on the distance moved by the first and second brake shoes 11 and 12 while releasing the drum brake 1. The shoe center clearance (SCC) between the centers can be calculated. Hereinafter, the center gap between the first brake shoe 11 and the drum 50 may be referred to as the first center gap SCC1, and the center gap between the second brake shoe 12 and the drum 50 may be referred to as the first center gap SCC1. 2 It can be called the center gap (SCC2). Additionally, the sum of the first center clearance (SCC1) and the second center clearance (SCC2) can be referred to as the total shoe center clearance (TSCC).

As shown in FIG. 6, while releasing the drum brake 1, the first and second brake shoes 11 and 12 may each move due to the retraction of the spindle-nuts 210 and 220. By each movement of the first and second brake shoes 11 and 12, each of the first and second brake shoes 11 and 12 may be spaced apart from the drum 50, and the first center gap SCC1 and the first center gap SCC1 may be spaced apart from each other. 2 Center gap (SCC2) and total center gap (TSCC) can be increased.

The increase in the first center gap SCC1 may be proportional to the moving distance of the first brake shoe 11. Additionally, the increase in the second center gap SCC2 may be proportional to the moving distance of the second brake shoe 12.

The ratio between the increase in the first and second center clearances SCC1 and SCC2 and the moving distance of the first and second brake shoes 11 and 12 is the first and second distances between the anchor block 20 and the center of the drum brake 1. It may correspond to the ratio between the first distance D1 and the second distance D2 between the anchor block 20 and the spindle-nuts 210 and 220.

The control unit 350 may calculate the total center clearance (TSCC) based on the distance moved by the first and second brake shoes 11 and 12 using [Equation 1].

[Equation 1]

Here, TSCC may represent the total center gap. D_shoe may represent the distance traveled by the brake shoes 11 and 12. D1 may represent the distance between the center of the anchor block 20 and the drum brake 1. Additionally, D2 may represent the distance between the anchor block 20 and the spindle-nuts 210 and 220.

In this way, the control unit 350 operates the driving motor 110 in response to the user input and can determine the total center clearance (TSCC) by the operation of the driving motor 110.

Additionally, the control unit 350 may prevent drag of the drum brake 1 while the vehicle is running based on the total center clearance (TSCC).

Figure 7 shows a fastening operation of a drum brake according to one embodiment.

7, the fastening operation 1000 of the drum brake 1 is explained.

The drum brake 1 may receive a user's brake engagement request (1010).

The control unit 350 may receive a user's brake engagement request from the vehicle's parking switch and/or brake pedal.

The drum brake 1 may drive the driving motor 110 in a first direction (forward direction) (1020).

The control unit 350 may drive the driving motor 110 in the first direction (forward direction) to engage the drum brake 1. Specifically, the control unit 350 may provide a control signal to the driving unit 340 to drive the driving motor 110 in the first direction.

The driving unit 340 may apply a driving voltage to the driving motor 110 to rotate the driving motor 110 in the first direction in response to a control signal from the controller 350 and supply a driving current to the driving motor 110. there is.

The drum brake 1 may determine whether the driving current of the driving motor 110 is greater than or equal to the first reference current (1030).

The current sensor 320 may measure the driving current supplied from the driving unit 340 to the driving motor 110 and provide an electrical signal corresponding to the measured driving current value to the control unit 350.

The control unit 350 may identify the driving current value of the driving motor 110 based on the output signal of the current sensor 320. The control unit 350 may compare the driving current value with the first reference current value and identify whether the driving current value is greater than or equal to the first reference current value.

The first reference current value may indicate that the linings 11b and 12b of the brake shoes 11 and 12 are in contact with the drum 50 . While the brake shoes 11 and 12 are moving, a relatively small drive current may be supplied to the drive motor 110. Thereafter, when the linings 11b and 12b of the brake shoes 11 and 12 contact the drum 50 and pressurize the drum 50, the drive current supplied to the drive motor 110 may rapidly increase. The control unit 350 may identify whether the driving current value is greater than or equal to the first reference current value in order to identify a sudden increase in the driving current.

The first reference current value indicating that the linings 11b and 12b of the brake shoes 11 and 12 are in contact with the drum 50 may be set experimentally or empirically.

If it is identified that the drive current is not more than the first reference current (No in 1030), the drum brake 1 can continue to drive the drive motor 110.

If it is identified that the driving current is greater than or equal to the first reference current (Yes in 1030), the drum brake 1 may stop driving the driving motor 110 (1040).

The control unit 350 may identify that the linings 11b and 12b of the brake shoes 11 and 12 are in contact with the drum 50 and pressurize the drum 50 based on the fact that the driving current is greater than or equal to the first reference current. . Accordingly, the control unit 350 may stop engaging the drum brake 1 based on the driving current being greater than or equal to the first reference current. Specifically, the control unit 350 may provide a control signal to the drive unit 340 to stop driving the drive motor 110.

As described above, the drum brake 1 may control the drive motor 110 to engage the drum brake 1 in response to a user input for engaging the drum brake 1.

Figure 8 shows a drum brake release operation according to one embodiment.

8, the release operation 1100 of the drum brake 1 is explained.

The drum brake 1 may receive a user's brake release request (1110).

The control unit 350 may receive a user's brake release request from the vehicle's parking switch and/or brake pedal.

The drum brake 1 may drive the driving motor 110 in the second direction (reverse direction) (1120).

The control unit 350 may drive the driving motor 110 in the second direction (reverse direction) to engage the drum brake 1. Specifically, the control unit 350 may provide a control signal to the driving unit 340 to drive the driving motor 110 in the second direction.

The driver 340 may apply a driving voltage to the drive motor 110 to rotate the drive motor 110 in the second direction in response to a control signal from the controller 350 and supply a drive current to the drive motor 110. there is.

The drum brake 1 may determine whether the driving current of the driving motor 110 is less than or equal to the second reference current (1130).

The control unit 350 may identify the driving current value of the driving motor 110 based on the output signal of the current sensor 320. The control unit 350 may compare the driving current value with the second reference current value and identify whether the driving current value is less than or equal to the second reference current value.

The first reference current value may indicate that the linings 11b and 12b of the brake shoes 11 and 12 are spaced apart from the drum 50. While the brake shoes 11 and 12 are in contact, a relatively large drive current may be supplied to the drive motor 110. Thereafter, when the linings 11b and 12b of the brake shoes 11 and 12 are separated from the drum 50, the drive current supplied to the drive motor 110 may be reduced. The control unit 350 may identify whether the driving current value is greater than or equal to the second reference current value in order to identify that the driving current has decreased.

The second reference current value indicating that the linings 11b and 12b of the brake shoes 11 and 12 are separated from the drum 50 may be set experimentally or empirically.

If it is identified that the drive current is not below the second reference current (No in 1130), the drum brake 1 can continue to drive the drive motor 110.

If it is determined that the driving current is less than or equal to the second reference current (Yes at 1130), the drum brake 1 may identify whether the elapsed time is more than the reference release time (1140).

The control unit 350 may identify that the linings 11b and 12b of the brake shoes 11 and 12 are spaced apart from the drum 50 based on the fact that the driving current is less than or equal to the second reference current. In addition, the control unit 350 operates the drive motor 110 for a predetermined reference release time in order to sufficiently separate the linings 11b and 12b from the drum 50 after the linings 11b and 12b are separated from the drum 50. It can be driven.

The control unit 350 may identify the time elapsed since the driving current reaches the second reference current in order to identify the time elapsed since the linings 11b and 12b are separated from the drum 50. In addition, the control unit 350 identifies whether the time elapsed after the drive current reaches the second reference current is longer than or equal to the reference release time in order to identify whether the linings 11b and 12b are sufficiently spaced apart from the drum 50. can do.

If it is identified that the elapsed time is not more than the reference release time (No in 1140), the drum brake 1 can continue to drive the drive motor 110.

If it is identified that the elapsed time is more than the reference release time (No in 1140), the drum brake 1 can calculate the moving distance of the brake shoes 11 and 12 (1150).

The control unit 350 can calculate the moving distance of the brake shoes 11 and 12 to identify whether the linings 11b and 12b are sufficiently spaced from the drum 50 based on the fact that the elapsed time is more than the reference release time. there is.

The control unit 350 may calculate the moving distance of the brake shoes 11 and 12 based on the driving voltage of the driving motor 110 and/or the temperature of the drum brake 1. For example, the control unit 350 may calculate the moving distance of the brake shoes 11 and 12 based on the motor characteristics and driving voltage of the driving motor 110. Additionally, the control unit 350 may calculate the moving distance of the brake shoes 11 and 12 by reflecting the no-load current and temperature changes of the driving motor 110.

The drum brake 1 may identify whether the estimated total center clearance (TSCC) is greater than or equal to the target center clearance (1160).

The control unit 350 may estimate the total center clearance (TSCC) based on the moving distance of the brake shoes 11 and 12. For example, the control unit 350 may estimate the total center gap (TSCC) using [Equation 1].

Movement of the brake shoes 11 and 12 by the drive motor 110 may be affected by the temperature of the drum brake 1. In other words, the total center clearance (TSCC) resulting from driving the drive motor 110 during the reference release time may be smaller than the target center clearance to prevent brake drag.

For this reason, the control unit 350 calculates the moving distance of the brake shoes 11 and 12 by reflecting the temperature of the drum brake 1, and calculates the total center-to-body gap based on the calculated moving distance of the brake shoes 11 and 12. (TSCC) can be estimated.

The control unit 350 may compare the estimated total center gap (TSCC) with the target center gap and identify whether the estimated total center gap (TSCC) is greater than or equal to the target center gap. Here, the target center gap may be set experimentally or empirically to a value for preventing brake drag.

If it is identified that the estimated total center clearance (TSCC) is not more than the target center clearance (No in 1160), the drum brake 1 may continue to drive the drive motor 110.

If it is identified that the estimated total center clearance (TSCC) is greater than or equal to the target center clearance (Yes at 1160), the drum brake 1 may stop driving the drive motor 110 (1170).

The control unit 350 may identify that sufficient center clearance to prevent drag is secured based on the estimated total center clearance (TSCC) being greater than or equal to the target center clearance. Accordingly, the control unit 350 may stop releasing the drum brake 1 based on the estimated total center clearance (TSCC) being greater than or equal to the target center clearance. Specifically, a control signal may be provided to the driving unit 340 to stop driving the driving motor 110.

As described above, the drum brake 1 may control the drive motor 110 to release the drum brake 1 in response to a user input for releasing the drum brake 1. In addition, the drum brake 1 estimates the total center clearance (TSCC) based on the temperature of the drum brake 1, and the total center clearance (TSCC) of the drum brake 1 is based on the estimated total center clearance (TSCC) being equal to or greater than the target center clearance. Conclusion can be stopped.

As described above, the disclosed embodiments have been described with reference to the attached drawings. A person skilled in the art to which the present invention pertains will understand that the present invention can be practiced in forms different from the disclosed embodiments without changing the technical idea or essential features of the present invention. The disclosed embodiments are illustrative and should not be construed as limiting.

1: Drum brake 11, 12: Brake shoe
50: drum 110: drive motor
120: reduction gear unit 200: power conversion unit
310: voltage sensor 320: current sensor
340: driving unit 350: control unit
351: Processor 352: Memory

Claims (14)

In the vehicle brake system,
a pair of brake shoes provided inside a drum that rotates together with the wheels of the vehicle;
a spindle and nut provided between the pair of brake shoes;
a drive motor configured to rotate the spindle;
a temperature sensor that outputs a signal corresponding to the temperature of the brake device; and
Including a processor that controls the driving motor,
The processor,
In response to receiving a brake release request, operating the drive motor to space the pair of brake shoes from the drum;
A brake device that stops operating the drive motor based on the drive voltage of the drive motor, the drive current of the drive motor, and the output signal of the temperature sensor. The method of claim 1, wherein the processor:
Estimating a center gap between the pair of brake shoes and the drum based on the driving voltage of the driving motor, the driving current of the driving motor, and the output signal of the temperature sensor,
A brake device that stops operating the drive motor based on the estimated center clearance being greater than or equal to the target center clearance. The method of claim 2, wherein the processor:
Estimating the rotational speed of the driving motor based on the driving voltage of the driving motor and the driving current of the driving motor,
A brake device that compensates for the rotational speed of the driving motor based on the output signal of the temperature sensor. The method of claim 3, wherein the processor:
Estimating a moving distance of each of the pair of brake shoes based on the compensated rotation speed,
A brake device that estimates a center gap between the pair of brake shoes and the drum based on the moving distance of each of the pair of brake shoes. The method of claim 2, wherein the processor:
A brake device that continues to operate the drive motor based on the estimated center clearance being no more than the target center clearance. The method of claim 1, wherein the processor:
In response to receiving a brake engagement request, operating the drive motor to cause the pair of brake shoes to approach the drum;
A brake device that stops operating the drive motor during applying the brake, based on the drive current of the drive motor being greater than or equal to a first reference current. The method of claim 1, wherein the processor:
Based on the driving current being less than or equal to the second reference current while releasing the brake, identifying whether the time elapsed since the driving current became less than or equal to the second reference current is greater than or equal to the reference time;
Estimating a center gap between the pair of brake shoes and the drum based on the elapsed time being greater than or equal to the reference time,
A brake device that stops operating the drive motor based on the estimated center clearance being greater than or equal to the target center clearance. A brake device including a pair of brake shoes provided inside a drum that rotates with the wheel of the vehicle, a spindle and nut provided between the pair of brake shoes, and a drive motor configured to rotate the spindle. In the control method,
In response to receiving a brake release request, operating the drive motor to space the pair of brake shoes from the drum;
A control method of a brake device comprising stopping operation of the drive motor based on the drive voltage of the drive motor, the drive current of the drive motor, and the temperature of the brake device. 9. The method of claim 8, wherein stopping operation of the drive motor comprises:
Estimating a center gap between the pair of brake shoes and the drum based on the driving voltage of the driving motor, the driving current of the driving motor, and the temperature of the brake device,
A control method of a brake device comprising stopping operation of the drive motor based on the estimated center clearance being greater than or equal to the target center clearance. The method of claim 9, wherein estimating the center gap between the pair of brake shoes and the drum comprises:
Estimating the rotational speed of the driving motor based on the driving voltage of the driving motor and the driving current of the driving motor,
A method of controlling a brake device further comprising compensating the rotational speed of the drive motor based on the temperature of the brake device. The method of claim 10, wherein estimating the center gap between the pair of brake shoes and the drum comprises:
Estimating a moving distance of each of the pair of brake shoes based on the compensated rotation speed,
A method of controlling a brake device further comprising estimating a center gap between the pair of brake shoes and the drum based on a movement distance of each of the pair of brake shoes. The method of claim 9, wherein the control method is:
The control method of a brake device further comprising continuing to operate the drive motor based on the estimated center clearance being not greater than or equal to the target center clearance. The method of claim 8, wherein the control method is:
In response to receiving a brake engagement request, operating the drive motor to cause the pair of brake shoes to approach the drum;
A method of controlling a brake device further comprising stopping operation of the drive motor based on a drive current of the drive motor being greater than or equal to a first reference current while applying the brake. 9. The method of claim 8, wherein stopping operation of the drive motor comprises:
Based on the driving current being less than or equal to the second reference current while releasing the brake, identifying whether the time elapsed since the driving current became less than or equal to the second reference current is greater than or equal to the reference time;
Estimating a center gap between the pair of brake shoes and the drum based on the elapsed time being greater than or equal to the reference time,
A control method of a brake device comprising stopping operation of the drive motor based on the estimated center clearance being greater than or equal to the target center clearance.

Images