Drum brake with forward pressure self-balancing function and adjusting method

Abstract

The invention relates to the technical field of mechanical braking, in particular to a drum brake with a forward pressure self-balancing function and an adjusting method.A pressure monitoring set is arranged on a brake clamping arm and used for detecting forward pressure applied to a brake drum by the brake clamping arm in real time; the distance adjusting mechanism is arranged between the brake clamping arm on at least one side and the cross rod linkage mechanism and used for adjusting the relative position of the brake clamping arm on the side and the cross rod linkage mechanism according to a detection signal of the pressure monitoring set so as to change the pre-tightening force of the brake clamping arm on the side to the brake drum; the control unit is electrically connected with the pressure monitoring set and the interval adjusting mechanism and used for receiving signals of the pressure monitoring set and controlling the interval adjusting mechanism to act. According to the brake and the adjusting method, asymmetric loads can be eliminated, a transmission shaft system can be protected, abrasion can be compensated in real time, the functions of redundancy check and safety protection are achieved, transient impact is eliminated, dynamic whole-process protection is achieved, and the brake safety of a crane under the complex working condition is ensured.

Description

Technical Field

[0001] This invention relates to the field of mechanical braking technology, and in particular to a drum brake with positive pressure self-balancing function and its adjustment method. Background Technology

[0002] As a core safety component in lifting and transport machinery, port machinery, and metallurgical equipment, the stability of drum brake performance and the symmetry of load directly affect the operational safety of the entire machine. Traditional drum brakes typically employ a crossbar linkage mechanism to synchronize the movement of the left and right brake arms, aiming to achieve synchronous contact between the left and right brake pads and the brake drum. However, long-term engineering practice has revealed the following significant drawbacks in the traditional structure: First, since the wear of the left and right friction pads is often inconsistent, and the mechanical clearance at the linkage hinge increases with the use time, it is difficult to ensure that the two side shoes contact the brake drum at the same time by relying solely on mechanical linkage. Once there is a millisecond-level deviation in the contact time, the brake drum will be subjected to a unidirectional lateral impact load in an instant, causing the drive shaft to generate transient bending stress. Long-term operation is very likely to cause fatigue shaft breakage accidents. Second, most existing automatic adjustment devices are purely mechanical structures based on displacement compensation, which cannot sense the real braking positive pressure. When the brake is closed, even if the displacement on both sides is symmetrical, the positive pressure on both sides is often unequal due to differences in the stiffness of the clamping arm, deformation of the support, or installation errors. This asymmetrical load will be transmitted to the reducer bearing and motor end through the brake drum, shortening the bearing life and reducing braking smoothness. Third, although attempts have been made in recent years to install single-point pressure sensors on the brake clamps for monitoring, the brake clamps are subjected to extremely complex forces during the braking process, and the center of pressure of the shoe contact will drift with the wear position. Single-point measurements often have large random errors and zero-point drift, making it difficult to accurately reflect the true center of the braking load, which leads to misjudgments by the control system.

[0003] Therefore, developing an intelligent drum brake that can accurately monitor positive pressure at multiple points on both sides in real time and achieve both transient and steady-state balance through active closed-loop control has become an urgent need to ensure the long-term safe operation of heavy-duty lifting equipment. Summary of the Invention

[0004] The main objective of this invention is to overcome the shortcomings of the prior art and provide a drum brake with positive pressure self-balancing function and adjustment method.

[0005] The technical solution adopted by this invention to achieve its technical objective is: a drum brake with positive pressure self-balancing function, comprising a base, a brake drum mounted on the base, brake arms arranged opposite to each other on the left and right sides, a pusher for driving the brake arms, and a crossbar linkage mechanism connecting the brake arms. The pusher, through the crossbar linkage mechanism, drives the opposite brake arms to contact or separate from the outer circumferential surface of the brake drum, thereby braking or releasing the brake drum. The invention is characterized by further comprising: A pressure monitoring group is installed on the brake arm to detect the positive pressure applied by the brake arm to the brake drum in real time. A spacing adjustment mechanism is disposed between at least one of the brake clamping arms and the crossbar linkage mechanism, and is used to adjust the relative position of the brake clamping arm and the crossbar linkage mechanism on that side according to the detection signal of the pressure monitoring group, so as to change the preload of the brake clamping arm on the brake drum on that side. The control unit is electrically connected to the pressure monitoring group and the spacing adjustment mechanism respectively, and is used to receive signals from the pressure monitoring group and control the operation of the spacing adjustment mechanism.

[0006] Preferably, the pressure monitoring group is fixedly installed on the brake clamp arm, one end of which is hinged to both ends of the base, and a brake pad is provided on the inner side to apply pressure to the brake drum.

[0007] Preferably, the brake clamp arm includes a left brake clamp arm and a right brake clamp arm, one end of which is hinged to both ends of the base, and both are provided with brake pads on their inner sides. The brake pads are configured as left friction pads and right friction pads, and pressure is applied to the brake drum through the left friction pads and right friction pads.

[0008] Preferably, the sides of the left and right brake arms are machined with mounting grooves or stress-sensing windows; the pressure monitoring group includes a left pressure detection group and a right pressure detection group, which are respectively embedded in the mounting grooves or stress-sensing windows.

[0009] The left pressure detection group includes an upper left pressure detector and a lower left pressure detector, which are symmetrically fixed on the left brake arm. The right-side pressure detection group includes an upper right pressure detector and a lower right pressure detector, which are symmetrically fixed on the right-side brake arm.

[0010] Preferably, the other end of the left and right opposing brake arms is fixedly mounted with a spring by two push rods, and the spring is horizontally spanned between the top ends of the left and right brake arms.

[0011] The left brake arm and the right brake arm are fixedly mounted with springs at their other ends by two push rods. The springs are horizontally spanned between the top ends of the left brake arm and the right brake arm, which is used to realize the synchronous opening and closing of the brake arms and to provide positive pressure for closing when the actuator is de-energized. The two push rods facilitate the installation of the springs.

[0012] Preferably, the spacing adjustment mechanism includes a drive motor, which is mounted on the brake arm via a motor fixing component and a nut fixing component. The lower end of the nut fastener is provided with a hinge hole, which is hinged to the pin at the upper end of the brake clamp arm on one side.

[0013] Preferably, the output end of the drive motor is fixedly connected to an adjusting screw, one end of which passes through a nut fixing member and is threadedly connected to the nut fixing member.

[0014] Preferably, the other end of the transmission screw is hinged to the crossbar linkage mechanism; The crossbar linkage mechanism is configured as a connecting rod, one end of which is simultaneously hinged to the transmission screw and the right brake clamp arm, the middle end is hinged to a support rod, and the other end is hinged to the pusher; The connecting rod is driven to rotate based on the support rod by the pusher, thereby driving the brake clamp arm to perform a braking action on the brake drum with the brake pads; and by driving the motor to rotate forward and reverse, the engagement length of the transmission screw in the nut fixing part can be changed, thereby independently adjusting the tilt angle position of the brake clamp arm on this side relative to the crossbar linkage mechanism without changing the spring length, so that the pressure on both sides of the brake drum is balanced.

[0015] The present invention also provides an adjustment method for a drum brake with positive pressure self-balancing function, comprising the following steps: S1. Signal Acquisition: During the braking closure process, pressure multi-dimensional data streams on the left and right opposing brake arms are acquired by the left pressure detection group and the right pressure detection group, respectively. S2. Difference Calculation: The control unit first performs weighted fusion processing on multiple signals from the same side, extracts the positive pressure characteristic value that reflects the true load on that side, and then calculates the difference between the characteristic values ​​on the left and right sides. S3. Threshold Judgment and Decision: Determine whether the absolute value of the difference exceeds the preset adjustment threshold; if it does, determine the adjustment direction of the spacing adjustment mechanism (drive motor forward or reverse rotation) according to the positive or negative sign of the difference. S4. Execution adjustment: The drive spacing adjustment mechanism is activated to change the position of the brake arm relative to the crossbar linkage mechanism, thereby adjusting the degree of contact between the brake arm and the brake drum on this side. S5. Closed-loop feedback: During the adjustment process, steps S1 to S4 are continuously cyclical until the difference falls back to the allowable error range, at which point the adjustment is stopped.

[0016] Preferably, the specific adjustment logic of step S3 is as follows: If it is determined that the pressure of the brake arm on one side with the spacing adjustment mechanism is less than that on the other side, the drive motor is controlled to reduce the initial back distance between the brake arm on that side and the brake drum (i.e., increase the clamping degree). If it is determined that the pressure of the brake arm on one side with the spacing adjustment mechanism is greater than that on the other side, the drive motor is controlled to increase the initial retraction distance between the brake arm on that side and the brake drum (i.e., reduce the clamping degree).

[0017] Preferably, the adjustment method further includes a fault protection mechanism: When the control unit detects that the signal on either the left or right pressure detection group is zero, open-circuited, or undergoes an abnormal change; Alternatively, when the drive motor operates continuously for more than a preset time but the pressure difference does not change significantly; The control unit automatically disables the spacing adjustment mechanism, locks the current position, and sends a fault alarm signal to the outside.

[0018] Preferably, in step S1, the signals from both sides are acquired using a synchronous sampling rate of not less than 1 kHz, and mechanical vibration noise is removed by first-order low-pass filtering. The control unit identifies the step point in the rising edge of the signal that breaks through a preset signal-to-noise ratio threshold as the contact feature point. The control unit records the time difference between the feature points on both sides. It is used as a characteristic parameter to determine the consistency of the dynamic response of the brake, and is used to pre-adjust the initial static pose of the displacement adjustment component under non-braking conditions.

[0019] The working principle and specific usage process of this brake and adjustment method are as follows: By integrating the pressure monitoring group, the spacing adjustment mechanism and the control unit, the real-time monitoring and active adjustment of the positive pressure applied by the brake clamp arm to the brake drum are realized to eliminate the uneven pressure on the left and right sides caused by wear or gap.

[0020] The specific operating procedure is as follows: During the braking closure process, the left and right pressure detection groups collect multi-dimensional pressure data streams from the left and right brake arms in real time; the control unit first performs weighted fusion processing on multiple signals from the same side, extracts positive pressure feature values, and calculates the difference between the left and right sides; if the absolute value of the difference exceeds the preset adjustment threshold, the adjustment direction of the drive motor is determined based on the positive or negative sign of the difference; the drive motor independently adjusts the tilt angle position of the corresponding side brake arm relative to the crossbar linkage mechanism by changing the engagement length of the transmission screw in the nut fixing part, thereby changing the preload of the brake pads on the brake drum on that side; during the adjustment process, the system continuously cycles the above steps through closed-loop feedback until the pressure difference between the two sides falls back to the allowable error range, thereby ensuring the pressure balance on both sides of the brake drum and eliminating asymmetrical loads.

[0021] Compared with the prior art, the beneficial effects of the present invention are: This drum brake and its adjustment method, which features positive pressure self-balancing, can eliminate asymmetrical loads and protect the transmission shaft system. Through active closed-loop adjustment, it ensures that the positive pressure of the left and right brake arms on the brake drum remains balanced, fundamentally eliminating the radial shear force and additional bending moment acting on the motor shaft or reducer shaft caused by uneven positive pressure, and significantly extending the service life of bearings and oil seals.

[0022] This drum brake and adjustment method with positive pressure self-balancing function can compensate for wear in real time and reduce maintenance costs: it can automatically identify and compensate for positive pressure deviation caused by uneven wear of friction plates or changes in mechanical clearance, replacing traditional manual adjustment and reducing the frequency of equipment maintenance and labor costs.

[0023] The drum brake and its adjustment method, which have a positive pressure self-balancing function, have an ingenious structure and are easy to modify: the spacing adjustment mechanism is cleverly integrated into the crossbar linkage system, without the need for major modifications to the main frame of the brake, making it easy to upgrade and modify existing drum brakes.

[0024] The drum brake and its adjustment method with positive pressure self-balancing function have redundancy verification and safety protection functions: by setting multiple pressure detection devices on the same side brake arm, the sensor redundancy verification and force center position determination are realized. At the same time, combined with the fault protection mechanism and mechanical limit, it is ensured that the system can lock the current position and issue an alarm under abnormal working conditions, thus realizing dual redundancy safety protection of mechanical and electrical systems.

[0025] This drum brake and its adjustment method, which features positive pressure self-balancing, can eliminate transient impacts and achieve dynamic full-process protection. By monitoring the timing sequence of left and right pressure application during braking at high frequency, it can effectively identify and correct dynamic asynchrony problems caused by uneven initial mechanical retraction distance. This avoids transient lateral displacement and impact load on the drive shaft caused by the brake drum being subjected to force on one side first, and achieves load balance throughout the entire process from the moment of brake contact to steady-state locking.

[0026] This drum brake and its adjustment method, which features positive pressure self-balancing, offer high control precision and stable operation. Employing weighted fusion processing technology for multi-point pressure signals on the same side, it effectively eliminates interference from the brake arm's own weight and local vibrations, obtaining an equivalent positive pressure signal that reflects the true force on the brake pads, significantly improving detection accuracy. Combined with a preset adjustment dead zone and mechanical self-locking function, it avoids oscillations and malfunctions during adjustment, ensuring the crane's braking safety under complex working conditions. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of the brake of the present invention.

[0029] Figure 2 This is a three-dimensional view of the spacing adjustment mechanism and the drive motor transmission structure.

[0030] Figure 3 This is a schematic diagram showing the force deformation of the brake clamp arm and the arrangement and pose of the dual sensors.

[0031] Figure 4 This is a diagram illustrating the operational steps of the brake adjustment method of the present invention.

[0032] Figure 5 This is a flowchart illustrating the brake adjustment method of the present invention.

[0033] The components include: 1. Pusher; 2. Support rod; 3. Crossbar linkage mechanism; 4. Spring; 5. Transmission screw; 6. Connecting assembly; 601. Motor fixing bracket; 602. Nut mounting seat; 603. Clamping arm connector; 7. Matching nut; 8. Drive motor; 9. Brake clamping arm; 901. Left brake clamping arm; 902. Right brake clamping arm; 10. Left pressure detection group; 1001. Upper left pressure detector; 1002. Lower left pressure detector; 11. Brake pad; 1101. Left friction pad; 1102. Right friction pad; 12. Brake drum; 13. Base; 14. Right pressure detection group; 1401. Upper right pressure detector; 1402. Lower right pressure detector. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0035] In the description of this invention, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to or indirectly connected to the other element.

[0036] In the description of this invention, it should be noted that the terms "center," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0037] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Example 1:

[0038] Please see Figures 1-3 A drum brake with positive pressure self-balancing function includes a base 13, a brake drum 12 mounted on the base 13, brake arms 9 arranged opposite to each other on the left and right, a pusher 1 that drives the brake arms 9 to move, and a crossbar linkage mechanism 3 that connects the brake arms 9. The pusher 1 drives the brake arms 9 opposite to each other on the left and right through the crossbar linkage mechanism 3 to contact or separate from the outer circumferential surface of the brake drum 12, thereby braking or releasing the brake drum 12.

[0039] Drum brakes also include a pressure monitoring group, a spacing adjustment mechanism, and a control unit.

[0040] In this embodiment, a pressure monitoring group is installed on the brake clamp arm 9 to detect the positive pressure applied by the brake clamp arm 9 to the brake drum 12 in real time. The pressure monitoring group is fixedly installed on the brake clamp arm 9, one end of which is hinged to both ends of the base 13, and a brake pad 11 is provided on the inner side to apply pressure to the brake drum 12 through the brake pad 11.

[0041] Furthermore, the brake arm 9 includes a left brake arm 901 and a right brake arm 902. One end of the left brake arm 901 and the right brake arm 902 are respectively hinged to both ends of the base 13, and each is provided with a brake pad 11 on its inner side. The brake pad 11 is configured as a left friction pad 1101 and a right friction pad 1102, and pressure is applied to the brake drum 12 through the left friction pad 1101 and the right friction pad 1102.

[0042] The sides of the left brake arm 901 and the right brake arm 902 are machined with mounting grooves or stress sensing windows; the pressure monitoring group includes a left pressure detection group 10 and a right pressure detection group 14, which are respectively embedded in the mounting grooves or stress sensing windows.

[0043] The left pressure detection group 10 includes an upper left pressure detector 1001 and a lower left pressure detector 1002, which are symmetrically fixed on the left brake arm 901. The right pressure detection group 14 includes an upper right pressure detector 1401 and a lower right pressure detector 1402, which are symmetrically fixed on the right brake arm 902.

[0044] In this embodiment, the other end of the left and right opposing brake arms 9 is fixedly installed with a spring 4 by two push rods. The spring 4 is horizontally spanned between the top ends of the left brake arm 901 and the right brake arm 902.

[0045] Among them, a spring 4 is fixedly installed between the other ends of the left brake clamp arm 901 and the right brake clamp arm 902 by two push rods. The spring 4 is horizontally spanned between the top ends of the left brake clamp arm 901 and the right brake clamp arm 902, which is used to realize the synchronous opening and closing of the brake clamp arms 9, and at the same time to provide the closing positive pressure when the pusher 1 is de-energized. The two push rods facilitate the installation of the spring 4.

[0046] In this embodiment, the spacing adjustment mechanism is disposed between the brake clamp arm 9 and the crossbar linkage mechanism 3 on at least one side, and is used to adjust the relative position of the brake clamp arm 9 and the crossbar linkage mechanism 3 on that side according to the detection signal of the pressure monitoring group, so as to change the preload of the brake clamp arm 9 on the brake drum 12.

[0047] Furthermore, the spacing adjustment mechanism includes a drive motor 8, which is mounted on the brake arm 9 through a motor fixing member 601 and a nut fixing member 602. The lower end of the nut fixing member 602 is provided with a hinge hole 603, which is hinged to a pin at the upper end of the brake arm 9 on one side.

[0048] An adjusting screw 5 is fixedly connected to the output end of the drive motor 8. One end of the adjusting screw 5 passes through the nut fixing member 602 and is threadedly connected to the nut fixing member 602. The other end of the transmission screw 5 is hinged to the crossbar linkage mechanism 3. The crossbar linkage mechanism 3 is set as a connecting rod. One end of the connecting rod is hinged to the transmission screw 5 and the right brake clamp arm 902, the middle end is hinged to the support rod 2, and the other end is hinged to the pusher 1. The actuator 1 drives the connecting rod to rotate based on the support rod 2, thereby driving the brake clamp arm 9 to perform a braking action on the brake drum 12 with the brake pads 11; and by driving the motor 8 to rotate forward and reverse, the engagement length of the transmission screw 5 in the nut fixing member 602 can be changed, thereby independently adjusting the tilt angle position of the brake clamp arm 9 on this side relative to the crossbar linkage mechanism 3 without changing the length of the spring 4, so that the pressure on both sides of the brake drum 12 is balanced.

[0049] In this embodiment, the control unit is electrically connected to both the pressure monitoring group and the spacing adjustment mechanism, and is used to receive signals from the pressure monitoring group and control the movement of the spacing adjustment mechanism. The control unit is a core processing unit (such as a PLC, microcontroller, or industrial computer), and includes a control decision module and a control output module, used to receive sensor signals, perform difference calculations, and make logical judgments, etc.

[0050] Specifically, during use, when the brake is in operation, the actuator 1 is de-energized, and the spring 4 releases energy to drive the left and right opposing brake arms 9 to move, causing the left friction pad 1101 and the right friction pad 1102 to press against the outer circumferential surface of the brake drum 12 to implement braking. During this process, the left pressure detection group 10 and the right pressure detection group 14, embedded and installed on the left brake arm 901 and the right brake arm 902, monitor the positive pressure in real time. The pressure signals collected by the upper left pressure detector 1001, the lower left pressure detector 1002, the upper right pressure detector 1401, and the lower right pressure detector 1402 are transmitted to the control unit. The control unit performs weighted fusion processing on the multi-dimensional data from the same side and... The pressure difference between the two sides is calculated. When the difference exceeds a preset threshold, the control unit commands the drive motor 8 to operate. The drive motor 8 is installed in conjunction with the nut fixing part 602 through the motor fixing part 601. Its output end drives the adjusting screw 5 to rotate, changing the engagement length of the adjusting screw 5 in the nut fixing part 602. Thus, without changing the length of the spring 4, the tilt angle position of the brake clamp arm 9 on this side relative to the crossbar linkage mechanism 3 is independently adjusted, thereby adjusting the preload of the left friction pad 1101 or the right friction pad 1102 on the brake drum 12. This adjustment process continues through closed-loop feedback until the pressure difference between the two sides falls back to the allowable error range, thereby achieving self-balancing of the pressure on both sides of the brake drum 12. Implementation: 2:

[0051] Please see Figures 4-5 Based on the above embodiments, this invention also provides an adjustment method for a drum brake with positive pressure self-balancing function, comprising the following steps: S1. Signal Acquisition: During the braking closure process, pressure multi-dimensional data streams on the left and right opposing brake arms 9 are acquired by the left pressure detection group 10 and the right pressure detection group 14, respectively.

[0052] In this step S1, a synchronous sampling rate of not less than 1kHz is used to acquire signals from both sides, and the signals are filtered by a first-order low-pass filter to remove mechanical vibration noise. The control unit identifies the step point in the rising edge of the signal that breaks through the preset signal-to-noise ratio threshold as the contact feature point; The control unit records the time difference between the feature points on both sides. It is used as a characteristic parameter to determine the consistency of the dynamic response of the brake, and is used to pre-adjust the initial static pose of the displacement adjustment component under non-braking conditions.

[0053] S2. Difference Calculation: The control unit first performs weighted fusion processing on multiple signals from the same side, extracts the positive pressure characteristic value that reflects the true load on that side, and then calculates the difference between the characteristic values ​​on the left and right sides.

[0054] S3. Threshold Judgment and Decision: Determine whether the absolute value of the difference exceeds the preset adjustment threshold; if it does, determine the adjustment direction of the spacing adjustment mechanism (drive motor 8 forward or reverse rotation) based on the sign of the difference. The specific adjustment logic of step S3 is as follows: If it is determined that the pressure of the brake clamp arm 9 on one side with the spacing adjustment mechanism is less than that on the other side, the drive motor 8 is controlled to operate to reduce the initial back distance between the brake clamp arm 9 on that side and the brake drum 12 (i.e., increase the clamping degree). If it is determined that the pressure of the brake clamp arm 9 on one side with the spacing adjustment mechanism is greater than that on the other side, the drive motor 8 is controlled to increase the initial retraction distance between the brake clamp arm 9 on that side and the brake drum 12 (i.e., reduce the clamping degree).

[0055] S4. Execution adjustment: The drive spacing adjustment mechanism is activated to change the position of the brake clamp arm 9 relative to the crossbar linkage mechanism 3, thereby adjusting the degree of contact between the brake clamp arm 9 and the brake drum 12 on this side.

[0056] S5. Closed-loop feedback: During the adjustment process, continuously cycle through steps S1 to S4 until the difference falls back to the allowable error range, then stop the adjustment.

[0057] S6. Fault protection mechanism: When the control unit detects that the signal on either side of the left pressure detection group 10 or the right pressure detection group 14 is zero, open circuit, or abnormal sudden change occurs; Alternatively, when the drive motor operates continuously for more than a preset time but the pressure difference does not change significantly; The control unit automatically disables the spacing adjustment mechanism, locks the current position, and sends a fault alarm signal to the outside.

[0058] like Figure 5 As shown, the adjustment method for this drum brake with positive pressure self-balancing function has the following detailed steps: Step S1, Initialization and Stress Estimation: When the brake enters the holding brake working state (start), the actuator 1 is de-energized, and the spring assembly 4 releases energy to clamp the arms. At this time, the control system reads the signals from the sensors on the left and right sides in real time through the detection system, and estimates the real-time positive pressure of the clamping arms 901 and 902, i.e., the positive pressure value, based on the preset calibration curve. and .

[0059] Step S2, Equilibrium State Determination: The system executes the following judgment logic: whether the positive pressure on both sides is consistent; In this step, the control unit calculates the pressure difference between the two sides. It is then compared with the preset allowable error range (adjusted dead zone ε).

[0060] Yes (consistent): If This indicates that the braking system is in a balanced state, and the process jumps directly to the "brake stops working" judgment without any mechanical adjustment to maintain system stability.

[0061] No (inconsistent): This indicates a significant positive pressure deviation, and the system enters the adjustment process.

[0062] Step S3, Calculation of control quantity: The calculation module is then used to solve for the 8 control quantities of the geared motor. The control unit calculates the required direction of motor rotation (forward or reverse) and the amplitude of the action (such as the number of pulses or the running time) based on the sign and magnitude of the difference ∆.

[0063] Scenario A (Left arm slightly loose): If the pressure on the left side is significantly less than that on the right side. The algorithm determines that the left side gap needs to be tightened, and instructs the drive motor 8 to rotate in the tightening direction.

[0064] Scenario B (Left arm is tighter): If the pressure on the left side is significantly greater than that on the right side. The algorithm determines that the left side gap needs to be relaxed, and instructs the drive motor 8 to rotate in the relaxation direction.

[0065] In this embodiment, the control unit also integrates braking response synchronization monitoring and feedback logic to eliminate transient impacts during braking. Specific implementation details are as follows: 1. Transient feature point capture: At the instant the braking action is initiated (i.e., the moment when the actuator 1 is de-energized and the spring 4 begins to release), the control unit increases the sampling frequency of the pressure detector to above 1kHz. The control unit monitors the rising edge of the pressure signal curves on both the left and right sides in real time.

[0066] The contact characteristic point is defined as the moment when the pressure signal begins to increase abruptly from zero (or the reference noise value). The contact moment on the left side is... Record the contact time on the right side as .

[0067] 2. Dynamic asynchrony judgment: The control unit calculates the time difference between the two sides contacting each other. .

[0068] If ∆t is positive and exceeds the set threshold (e.g., exceeds 50ms), it is determined that the right brake shoe contacts the brake drum before the left brake shoe. If ∆t is negative and its absolute value exceeds the set threshold, it is determined that the left brake pad contacts the brake drum before the right brake pad.

[0069] This minute difference in time can cause the brake drum to be subjected to a unidirectional lateral force for a very short period of time, thereby generating a transient bending impact on the drive shaft.

[0070] 3. Preventative initial backlash adjustment: Unlike the aforementioned static regulation based on "pressure difference", this logic compensates for response lag by adjusting the "initial backoff distance".

[0071] If premature contact on the left side is detected After the braking ends and the brakes are released, the control unit commands the drive motor 8 to slightly drive the adjusting transmission screw 5 to moderately increase the initial retraction distance of the left brake arm. Conversely, the initial backoff distance is reduced.

[0072] 4. Collaborative work logic: The control unit employs a dual principle of "dynamic time synchronization" and "static pressure balance." Within the first 0.5 seconds of braking, time synchronization is prioritized and deviations are recorded. Pressure difference compensation is then performed after braking reaches a steady state. This dual-dimensional adjustment not only ensures equal forces on both sides after the vehicle comes to a complete stop but also prevents lateral impact loads at the moment of contact, thus protecting the motor shaft and reducer shaft from a dynamic perspective throughout the entire process.

[0073] Step S4: Perform mechanical adjustment: The control unit outputs a command to drive the geared motor 8 to rotate the screw.

[0074] The rotation of the transmission screw 5 causes a slight adjustment in the position of the left brake clamping arm 901 relative to the crossbar linkage mechanism, changing the lever arm or preload state of the spring force on the left clamping arm, thereby adjusting its pressure on the brake drum. During the adjustment process, the sensor data changes in real time.

[0075] Step S5, Loop Monitoring and End: After a single adjustment action is completed, the system determines whether the brake has stopped operating (i.e. whether it has received a command to release the crane's brakes).

[0076] No (Continuous Monitoring): If the brake is still in the holding brake state, the process line returns to the starting point (e.g., Figure 5(As indicated by the arrow) The "estimate the positive pressure of the clamping arm" is performed again. This means that the adjustment is a dynamic approximation closed-loop process, and the system will continuously fine-tune until the pressure difference on both sides falls back to the allowable range.

[0077] Yes (End): If a crane brake release command is received, the process ends, the system resets and goes into standby mode, waiting for the next brake cycle.

[0078] Step S6, Fault Protection Mechanism: To prevent mechanical jamming that could cause motor overload, the control system also has a built-in timeout protection logic: if the drive motor 8 operates continuously for more than a preset time (e.g., 3 seconds) but the pressure difference ∆P on both sides does not change significantly, the system will forcibly stop the motor output and issue an alarm signal to prompt manual inspection.

[0079] The transmission screw is equipped with a mechanical limit switch to limit the maximum adjustment stroke of the motor and prevent braking failure due to over-adjustment.

[0080] The solution in this embodiment can be selectively combined with solutions in other embodiments.

[0081] It should be noted that although the above embodiments have been described herein, this does not limit the scope of patent protection of this invention. Therefore, any changes and modifications made to the embodiments based on the innovative concept of this invention, or equivalent structural, procedural, or functional transformations made using the description and drawings of this invention, directly or indirectly applying the above technical solutions to other related technical fields, are all included within the scope of protection of this invention.

Claims

1. A drum brake with positive pressure self-balancing function, comprising a base (13), a brake drum (12) mounted on the base (13), brake arms (9) arranged opposite to each other on the left and right, a pusher (1) for driving the brake arms (9) to move, and a crossbar linkage mechanism (3) connecting the brake arms (9), wherein the pusher (1) drives the opposite brake arms (9) to contact or separate from the outer circumferential surface of the brake drum (12) through the crossbar linkage mechanism (3), thereby braking or releasing the brake drum (12), characterized in that, Also includes: A pressure monitoring group is installed on the brake clamp arm (9) to detect the positive pressure applied by the brake clamp arm (9) to the brake drum (12) in real time; A spacing adjustment mechanism is provided between at least one side of the brake clamp arm (9) and the crossbar linkage mechanism (3) to adjust the relative position of the brake clamp arm (9) and the crossbar linkage mechanism (3) according to the detection signal of the pressure monitoring group, so as to change the preload of the brake clamp arm (9) on the brake drum (12). The control unit is electrically connected to the pressure monitoring group and the spacing adjustment mechanism respectively, and is used to receive signals from the pressure monitoring group and control the operation of the spacing adjustment mechanism.

2. A drum brake with positive pressure self-balancing function according to claim 1, characterized in that, The pressure monitoring group is fixedly installed on the brake clamp arm (9). One end of the brake clamp arm (9) is hinged to both ends of the base (13), and a brake pad (11) is provided on the inner side. The brake pad (11) applies pressure to the brake drum (12).

3. A drum brake with positive pressure self-balancing function according to claim 2, characterized in that, The other end of the left and right opposing brake arms (9) is fixed with a spring (4) by two push rods. The spring (4) is horizontally spanned between the top ends of the left brake arm (901) and the right brake arm (902).

4. A drum brake with positive pressure self-balancing function according to claim 2, characterized in that, The spacing adjustment mechanism includes a drive motor (8), which is mounted on the brake arm (9) through a motor fixing part (601) and a nut fixing part (602). The lower end of the nut fastener (602) is provided with a hinge hole (603), which is hinged to the pin at the upper end of the brake clamp arm (9) on one side.

5. A drum brake with positive pressure self-balancing function according to claim 4, characterized in that, An adjusting screw (5) is fixedly connected to the output end of the drive motor (8). One end of the adjusting screw (5) passes through the nut fixing member (602) and is threadedly connected to the nut fixing member (602).

6. A drum brake with positive pressure self-balancing function according to claim 5, characterized in that, The other end of the transmission screw (5) is hinged to the crossbar linkage mechanism (3); The crossbar linkage mechanism (3) is configured as a connecting rod. One end of the connecting rod is simultaneously hinged to the transmission screw (5) and the right brake clamp (902), the middle end is hinged to the support rod (2), and the other end is hinged to the pusher (1).

7. A method for adjusting a drum brake with positive pressure self-balancing function, applied to the drum brake according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Signal Acquisition: During the braking closure process, pressure multi-dimensional data streams on the left and right opposing brake arms (9) are acquired by the left pressure detection group (10) and the right pressure detection group (14), respectively. S2. Difference Calculation: The control unit first performs weighted fusion processing on multiple signals from the same side, extracts the positive pressure characteristic value that reflects the true load on that side, and then calculates the difference between the characteristic values ​​on the left and right sides. S3. Threshold Judgment and Decision: Determine whether the absolute value of the difference exceeds a preset adjustment threshold; If the difference exceeds the limit, the adjustment direction of the spacing adjustment mechanism is determined according to the sign of the difference. S4. Execution adjustment: Drive the gap adjustment mechanism to change the position of the brake arm (9) relative to the crossbar linkage mechanism (3), thereby adjusting the degree of contact between the brake arm (9) and the brake drum (12) on this side; S5. Closed-loop feedback: During the adjustment process, steps S1 to S4 are continuously cyclical until the difference falls back to the allowable error range, at which point the adjustment is stopped.

8. The adjustment method for a drum brake according to claim 7, characterized in that: The specific adjustment logic for step S3 is as follows: If it is determined that the pressure of the brake arm (9) on one side with the spacing adjustment mechanism is less than that on the other side, the drive motor (8) is controlled to operate to reduce the initial retraction distance between the brake arm (9) on that side and the brake drum (12). If it is determined that the pressure of the brake arm (9) on one side with the spacing adjustment mechanism is greater than that on the other side, the drive motor (8) is controlled to increase the initial retraction distance between the brake arm (9) on that side and the brake drum (12).

9. The adjustment method for a drum brake according to claim 8, characterized in that: The adjustment method also includes a fault protection mechanism: When the control unit detects that the signal on either side of the left pressure detection group (10) or the right pressure detection group (14) is zero, open circuit, or abnormal sudden change; Alternatively, when the drive motor operates continuously for more than a preset time but the pressure difference does not change significantly; The control unit automatically disables the spacing adjustment mechanism, locks the current position, and sends a fault alarm signal to the outside.

10. The adjustment method for a drum brake according to claim 7, characterized in that: Step S1 uses a synchronous sampling rate of not less than 1kHz to acquire signals from both sides, and then performs a first-order low-pass filter to remove mechanical vibration noise. The control unit identifies the step point in the rising edge of the signal that breaks through a preset signal-to-noise ratio threshold as the contact feature point. The control unit records the time difference ∆t between the feature points on both sides and uses it as a feature parameter to determine the consistency of the dynamic response of the brake, which is used to pre-adjust the initial static pose of the displacement adjustment component under non-braking conditions.

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