CN115614405A

CN115614405A - Brake torque on-line monitoring system and method

Info

Publication number: CN115614405A
Application number: CN202211172197.8A
Authority: CN
Inventors: 王志刚; 程志彦; 赵涓涓; 王园; 赵晋泽; 武钰
Original assignee: Shanxi Engineering Vocational College
Current assignee: Shanxi Engineering Vocational College
Priority date: 2022-09-26
Filing date: 2022-09-26
Publication date: 2023-01-17

Abstract

The invention discloses a braking torque on-line monitoring system and a method, wherein the system comprises: the device comprises at least two sensing modules and a control module; each sensing module is vertically arranged between the brake and the support, the top end of each sensing module is connected with the bottom of the brake, the bottom end of each sensing module is connected with the top of the support and is respectively used for bearing pressure and tension between the brake and the support during braking, and strain gauges are arranged on the sensing modules and are used for monitoring pressure or tension data; the control module is electrically connected with the strain gauge and used for receiving pressure or tension data and acquiring braking torque according to the pressure or tension data. The sensing module is arranged between the brake and the support, so that the complex type arranged on the brake body is avoided, the braking torque of the brake acting on the transmission chain can be monitored on line, the magnitude of the braking torque of the transmission chain can be reflected accurately in time, whether the braking performance of the brake is in a problem or not is judged intelligently, and the safety and the reliability of a braking system are ensured.

Description

Braking torque on-line monitoring system and method

Technical Field

The invention relates to the technical field of hoisting equipment, in particular to a braking torque online monitoring system and method.

Background

In a traditional crane hoisting mechanism, a drum brake or a disc brake is usually used for stopping a transmission chain and keeping a heavy object, the drum brake or the disc brake is not provided with a sensor for detecting braking torque applied to a brake wheel or a brake disc by the drum brake or the disc brake, and regular inspection of an equipment point inspector is generally relied on for finding out the problems of whether the braking force of the brake is properly set, whether the thickness of a friction plate is enough, whether the back distance of a pusher is within a required range and the like, and the problems are processed and solved on site, so that the performance of the brake is ensured to be good, the safety and the reliability of the hoisting mechanism can be ensured, and accidents such as hook slipping and the like are prevented.

In recent years, along with the continuous improvement of the intelligent requirement, more and more users require that the brake of the crane can timely sense the brake torque loaded on the transmission chain of the hoisting mechanism, and if the brake torque can be sensed in real time, whether the brake performance is good or not can be judged according to the change of the brake torque, so that a worker can be timely reminded to maintain the brake, and the state and the performance of the brake are guaranteed to be good. Fig. 1 and 2 are front and side views, respectively, of a drum brake, and fig. 3 and 4 are front and side views, respectively, of a disc brake. In the prior art, part of brake manufacturers make a pin shaft hinged with a fixed friction plate in a brake into a sensor, or install the sensor on an arm support of the fixed pin shaft to sense the reaction force generated when the friction plate of the brake acts on a brake wheel or a brake disc; furthermore, the brake with the sensor can only sense the positive pressure of the friction plate on the brake wheel or the brake disc, the product of the positive pressure, the friction coefficient and the acting arm is the braking torque generated by the brake, and the friction coefficient is not constant and can be changed continuously due to the use condition of the friction plate, the brake wheel or the brake disc. Therefore, the sensor-mounted brake cannot completely and accurately sense the braking torque loaded on the transmission chain of the hoisting mechanism.

Disclosure of Invention

In order to solve part or all of the technical problems in the prior art, the invention provides a braking torque online monitoring system and a braking torque online monitoring method. The technical scheme is as follows:

in a first aspect, an online braking torque monitoring system is provided, which includes: the system comprises at least two sensing modules and a control module; each sensing module is vertically arranged between the brake and the support, the top end of each sensing module is connected with the bottom of the brake, the bottom end of each sensing module is connected with the top of the support and is respectively used for bearing pressure and tension between the brake and the support during braking, and strain gauges are arranged on the sensing modules and are used for monitoring pressure or tension data; the control module is electrically connected with the strain gauge and used for receiving pressure or tension data and acquiring braking torque according to the pressure or tension data.

In some optional implementations, the sensing module includes two connection plates and a cylinder disposed between the two connection plates, the two connection plates are respectively connected with the brake and the support, and the strain gauge is disposed on the cylinder.

In some optional implementation manners, a set of strain gauges is arranged on each side face of the cylinder, and the multiple sets of strain gauges are distributed on the outer wall of the cylinder along the circumferential direction.

In some optional implementations, each set of strain gauges includes 2 vertical strain gauges and 2 transverse strain gauges, the 2 vertical strain gauges are arranged in parallel at intervals along the height direction of the cylinder, and the 2 transverse strain gauges are respectively arranged above and below the 2 vertical strain gauges in a transverse mode.

In some optional implementation modes, the connecting plate is a rectangular plate with a hole in the middle, and the connecting plate is connected with the brake or the base through a bolt.

In some optional implementation manners, the brake system further comprises an alarm module, wherein the alarm module is connected with the control module and used for sending out an alarm signal when the braking torque is abnormal.

In a second aspect, a method for online monitoring of brake torque by using the online brake torque monitoring system described in any one of the above is provided, and the method includes:

the control module receives tension or pressure data measured by the strain gauge on the sensing module and acquires braking torque according to the received tension and pressure data.

In some alternative implementations, the braking torque is obtained from the values of the tension and pressure by the following formula:

Mm＝N11×L+N9×K；

in the formula, N11 is a tension or pressure value measured by one sensing module, L is a distance from the sensing module to a vertical central axis of the brake, N9 is a tension or pressure value measured by another sensing module, K is a distance from the sensing module to the vertical central axis of the brake, and Mm is a braking torque.

In some optional implementations, the method further comprises: and when the braking torque is abnormal, the control module controls the alarm module to send out an alarm signal.

The technical scheme of the invention has the following main advantages:

according to the system and the method for monitoring the braking torque on line, the sensing module is arranged between the wheel brake or the disc brake and the support, so that a complex type arranged on a brake body is avoided, the braking torque of the brake acting on a transmission chain can be monitored on line, the magnitude of the braking torque of the transmission chain can be timely and accurately reflected, and the problem reflected by the change condition of the torque in a period of time is solved, so that whether the braking performance of the brake is in a problem or not can be intelligently judged, and the safety and the reliability of a braking system can be ensured. The brake has the advantages that the complex type and high cost of the existing brake torque sensor additionally arranged on the brake body are replaced, the negotiation with a brake manufacturer or the replacement of a new brake is not needed, only the sensing module is arranged between the brake and the support, all brakes in use can be reconstructed at low cost, and meanwhile, the accuracy of the monitored brake torque can be improved.

Drawings

The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a front elevational view of a drum brake provided in the prior art;

FIG. 2 is a side view of a drum brake provided by the prior art;

FIG. 3 is a front view of a prior art disc brake;

FIG. 4 is a side view of a prior art disc brake;

FIG. 5 is a schematic structural diagram of an online braking torque monitoring system applied to a drum brake according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of an on-line braking torque monitoring system applied to a disc brake according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a sensing module in the online braking torque monitoring system according to an embodiment of the present invention;

FIG. 8 is a braking torque curve of a brake during braking according to an embodiment of the present invention;

FIG. 9 is a force analysis diagram of a brake wheel according to an embodiment of the present invention;

FIG. 10 is a force analysis diagram of a drum brake according to an embodiment of the present invention;

FIG. 11 is a force analysis diagram of a sensing module according to an embodiment of the invention;

fig. 12 is a force diagram of two sensing modules according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

The technical scheme provided by the embodiment of the invention is described in detail below with reference to the accompanying drawings.

In a first aspect, an embodiment of the present invention provides an online braking torque monitoring system, as shown in fig. 5 to 7, including: at least two sensing modules 5 and a control module; each sensing module 5 is vertically arranged between the brake and the support, the top end of each sensing module is connected with the bottom of the brake, the bottom end of each sensing module is connected with the top of the support and is respectively used for bearing the pressure and the tension between the brake and the support during braking, and strain gauges 53 are arranged on the sensing modules 5 and are used for monitoring pressure or tension data; the control module is electrically connected with the strain gauge 53 and is used for receiving pressure or tension data and acquiring braking torque according to the pressure or tension data.

The online monitoring system for the braking torque provided by the embodiment of the invention can be applied to a crane hoisting mechanism or other systems provided with the same type of brakes, the sensing module 5 is arranged between the wheel type brake or the disc type brake and the support, the complex type arranged on the brake body is avoided, the braking torque of the brake acting on a transmission chain can be monitored online, the magnitude of the braking torque of the transmission chain can be reflected timely and accurately, and the problem reflected by the change condition of the torque in a period of time is reflected, so that whether the braking performance of the brake has a problem or not can be judged intelligently, and the safety and the reliability of the braking system are ensured. The invention is simple and reliable, can directly reflect the braking torque of the brake, has simple and convenient manufacture, installation and maintenance and wide application prospect, not only replaces the complex type and high cost of the existing brake body which is additionally provided with a braking torque sensor, but also does not need to consult with a brake manufacturer or replace a new brake, only the sensing module 5 is arranged between the brake and the support, can reform all brakes in use at low cost, and can improve the accuracy of the monitored braking torque.

In some alternative implementations, as shown in fig. 7, the sensing module 5 includes two connection plates 51 and a cylinder 52 disposed between the two connection plates 51, the two connection plates 51 are respectively connected with the brake and the support, and the strain gauge 53 is disposed on the cylinder 52. So set up, be convenient for sensing module 5 and stopper and support be connected, and can accomplish accurately and draw, pressure monitoring.

In some optional implementations of the present embodiment, a set of strain gauges 53 is disposed on each side surface of the cylinder 52, and the sets of strain gauges 53 are distributed circumferentially on the outer wall of the cylinder 52. So set up, improve stress monitoring's accuracy.

Further, as shown in fig. 7, each group of strain gauges 53 includes 2

vertical strain gauges

53 and 2 transverse strain gauges 53, the 2 vertical strain gauges 53 are arranged in parallel at intervals in the height direction of the cylinder 52, and the 2 transverse strain gauges 53 are arranged transversely above and below the 2 vertical strain gauges 53, respectively. 4 bar strain gauges 53 divide vertical and horizontal two directions respectively to arrange, can carry out omnidirectional stress measurement, improve measurement accuracy.

Of course, the two connection plates 51 may be supported and connected by other manners as long as they can bear pulling and pressure and are convenient for pulling and pressure monitoring, which is not specifically limited in this embodiment and can be set by those skilled in the art according to actual working conditions.

In some alternative implementations of this embodiment, the connecting plate 51 is a rectangular plate with a hole in the middle, and the connecting plate 51 is connected to the stopper or the base through a bolt. The rectangular plate is large in contact area with the brake or the base, and the connecting portion is stable and can ensure a force transmission effect. A hole in the middle of the connecting plate 51 facilitates mounting of the bolt.

In some optional implementation manners of the embodiment, the online braking torque monitoring system may further include an alarm module, and the alarm module is connected to the control module and configured to send an alarm signal when the braking torque is abnormal. Through setting up alarm module, be convenient for inform the staff fast when braking moment is unusual, the suggestion staff in time maintains the stopper, ensures braking system's safety and reliability.

The working principle of the brake torque online monitoring system is described in the following with specific examples:

the first embodiment is as follows:

in the hoisting mechanism of the crane, the brake adopts a normally closed brake, namely the brake is opened by a pusher during opening, and the friction plate is pressed on a brake wheel or a brake disc by means of the equipped spring force during upper brake. Meanwhile, because of the particularity of the lifting mechanism, no matter which direction the lifting mechanism rotates, the stress direction of the lifting mechanism is always the gravity direction of the lifted heavy object, and therefore, the moment acting on the brake wheel or the brake disc is always the same direction.

The schematic structure of the brake torque online monitoring brake system applied to the drum brake can be seen in fig. 5. In this embodiment, regardless of the direction of turning of the brake drum 2, the torque of the heavy object received by the brake drum 2 is always in one direction, and assuming that the torque of the heavy object received by the brake drum 2 is in the clockwise direction in the figure, the rotational torque generated on the brake drum 2 when the drum brake 1 is applied (contracting brake) should be in the counterclockwise direction. The traditional scheme is that the drum brake 1 is directly installed on a planar support 4 on a crane trolley frame 3 by virtue of a base, and the scheme is that 2 sensing modules 5 are additionally installed between the drum brake base and the support 4, when the drum brake 1 is braked, the drum brake 2 is driven to rotate clockwise, but the drum brake is fixed on the 2 sensing modules 5 and can not rotate, so that the left sensing module 5 bears the tensile force generated by the brake 1 when the drum brake 1 is braked, and the right sensing module 5 bears the pressure. The braking torque of the drum brake 1 acting on the brake wheel 2 can be calculated through the pressure or the tension measured by the sensing module 5.

Example two:

the schematic structure of the braking torque on-line monitoring braking system applied to the disc brake can be seen in fig. 6. As above, regardless of the direction of rotation of the brake disk 6, the moment of the weight received by the brake disk 6 is always one direction, and assuming that the moment of the weight received by the brake disk is clockwise in the figure, the rotational moment generated on the brake disk 6 when the disk brake 7 is applied should be counterclockwise. The disc brake 7 is usually arranged on the side of the brake disc 6 which is pressed against, and sometimes on both sides in order to meet the braking torque requirements, the support of the disc brake 7 on the other side is subjected to tensile forces. In the scheme, 2 sensing modules 5 are additionally arranged between bases of 2 disc brakes 7 and a support 4, the sensing module 5 on the left side bears tension generated by brake-on of the brakes 7 when the brake-on of the disc brakes 7 brakes, and the sensing module 5 on the right side bears pressure. The braking torque of the disc brake 7 acting on the brake disc 6 can be calculated from the pressure or tensile force measured by the sensor module 5.

In a second aspect, an embodiment of the present invention provides a method for performing online braking torque monitoring by using the online braking torque monitoring system described in any one of the foregoing embodiments, where the method includes:

When the hoisting mechanism hoists the heavy object, the transmission chain rotates, and at the moment, the brake overcomes the elastic force of the spring group to open the brake under the action of the pusher, namely, the brake is opened; when the transmission chain of the hoisting mechanism stops rotating, the brake acts, the brake is powered off, the pusher retracts, the elastic force of the spring group pushes the friction plate to press the brake wheel or the brake disc, so that the transmission chain stops rotating, and the change curve of the braking torque of the brake in the braking process of the brake is shown in the attached figure 8.

As can be seen from fig. 8, the braking torque reaches a maximum value quickly after the brake is applied, and stabilizes at a certain torque after a certain value is dropped. Likewise, the same is true for the tension or compression force measured by the sensing module 5. The maximum braking torque of the brake acting on the brake wheel or the brake disc can be calculated according to the maximum numerical value, the maximum braking torque is compared with the preset braking torque, if the maximum braking torque is within the required range, the maximum braking torque is considered to meet the requirement, and otherwise, the system is prompted to be overhauled; meanwhile, whether the braking performance of the brake is changed, namely the braking performance is changed or not is judged through the change of the braking torque within a period of time, the braking performance is changed, namely the braking performance is changed or is changed, and the braking performance is changed or is changed (generally, the braking performance is changed slowly), if the braking performance is changed suddenly, a control system is prompted to arrange personnel to overhaul and maintain the brake in time, so that the normal operation of the braking system is ensured.

Specifically, according to the values of the tension and the pressure, the braking torque is obtained by the following formula:

Mm＝N11×L+N9×K；

in the formula, N11 is a tension or pressure value measured by one sensing module, L is a distance (i.e., a moment arm) from the sensing module to a vertical central axis of the brake, N9 is a tension or pressure value measured by another sensing module, K is a distance (i.e., a moment arm) from the sensing module to the vertical central axis of the brake, and Mm is a braking torque. The detailed reasoning process is as follows:

the stresses of the brake wheel, the drum brake and the sensing module are analyzed to calculate the relationship between the braking torque of the drum brake acting on the brake wheel and the stress measured by the sensing module. Because the influence of the gravity of each part on the actual braking torque and the force borne by the sensing module is small and can be ignored, the influence of the gravity is not considered in the following force analysis.

Fig. 9 is a force analysis diagram of the brake wheel 2. The axial extension of the headblock 2 limits the freedom of the headblock 2 in other directions, which can only be rotated along its axis. For this purpose, only the forces influencing the rotation of the brake wheel 2 are taken into account here. Brake shoes on two sides of the drum brake 1 act on two sides of the brake wheel 2, the brake wheel 2 bears positive pressure N1 and N2 of the brake shoes and tangential friction force F1 and F2 generated by the positive pressure, and the pair of tangential friction force F1 and F2 forms braking torque Mm of the drum brake 1 on the brake wheel 2, the braking torque is opposite to the torque Mz of a heavy object acting on the brake wheel 2 through a transmission chain, but the value is large or small, so that the brake wheel can stop rotating quickly. The calculation formula is as follows:

f1= μ × N1F 2= μ × N2 μ is a friction coefficient between the brake shoe and the brake wheel

Mm＝F1×R+F2×R>Mz

Due to the structural arrangement of the drum brake 1, normally, the positive pressures N1 and N2 of the brake shoes on the two sides of the drum brake 1 borne by the brake wheel 2 are equal in magnitude and opposite in direction, and then the calculation formula is as follows:

F1＝μ×N1 F2＝μ×N2 N1＝N2 F1＝F2

Mm＝F1×R+F2×R＝2×μ×N1×R>Mz

fig. 10 is a force analysis diagram of the drum brake 1. The drum brake 1 bears the reaction forces N1F and N2F of the positive pressures N1 and N2 borne by the brake wheel 2, and the tangential friction forces F1F and F2F generated by the reaction forces N1F and N2F; the two ends of the base of the drum brake 1 are connected with pre-tightening forces N3 and N5 of bolts of 2 sensing modules 5 and reaction forces N4 and N6 of the pre-tightening forces N3 and N5; the drum brake 1 tends to rotate clockwise under the driving of the brake wheel 2, but the base of the drum brake is fixed on the 2 sensor modules 5, so that the sensor modules 5 on the left side cannot rotate, the force N7 applied to the brake base on the left side is downward, and the force N8 applied to the brake base on the right side is upward, so that the drum brake 1 is prevented from rotating. The positive pressures N1 and N2 and the reaction forces N1F and N2F are equal in size and opposite in direction, the tangential friction forces F1F and F2F and the tangential friction forces F1 and F2 are also equal in size and opposite in direction, and the moment Mmf generated by the brake is also equal in size and opposite in direction to the braking moment Mm of the brake 1 on the brake wheel 2; the pretightening force N3 and the reaction force N4 are equal in size and opposite in direction, the pretightening force N5 and the reaction force N6 are equal in size and opposite in direction, and the 4 forces are mutually counteracted, so that the rotation trend of the brake 1 is not influenced, and the position of the brake 1 is only fixed; the forces N7 and N8 of the sensing module 5 acting on the brake base are equal in magnitude and opposite in direction, but different in acting position, so that the rotating moment Mc relative to the axis of the brake wheel 2 is generated together, the rotating moment Mc is opposite in direction and equal in magnitude to the moment Mmf generated by the brake wheel 2 to the brake 1, and the dynamic balance of the brake 1 is kept. The calculation formula is as follows:

N1＝N2＝N1f＝N2f

F1f＝F2f＝F1＝F2

Mmf＝Mm

N3＝N4 N5＝N6

mc = N7 × L + N8 × K L, K are the moment arms of the forces N7, N8 with respect to the axis of the brake wheel 2, mm = Mmf = Mc = N7 × L + N8 × K, respectively

Fig. 11 is a force analysis diagram of the sensing module 5: the left sensing module 5 bears the pulling force N11 exerted by the drum brake 1 and the pulling force N12 exerted by the support 4, the 2 forces are equal in magnitude and opposite in direction, and the pulling force N11 and the force N7 are a pair of acting force and counterforce which are equal in magnitude and opposite in direction; the right sensor module 5 receives the pressure N9 applied by the drum brake and the pressure N10 applied by the support 4, the 2 forces are equal in magnitude and opposite in direction, and the pressure N9 and the force N8 are a pair of acting force and reaction force which are equal in magnitude and opposite in direction. The tensile force or pressure applied to the sensing module 5 can be measured through the strain gauge arranged on the sensing module, and the calculation formula is as follows:

N11＝N12＝N7 N9＝N10＝N8

from the above formula, the relationship between the braking torque applied to the brake wheel 2 by the drum brake 1 and the force measured by the sensing module can be derived:

Mm＝N7×L+N8×K＝N11×L+N9×K

thus, the braking torque applied to the brake wheel 2 by the drum brake 1 can be calculated through the tension N11 and the pressure N9 measured by the sensing module 5.

In the same way, the braking torque of the disc brake 7 acting on the brake disc 6 can be derived.

The above-mentioned N11 and N7, N9 and N8 acting forces act on a plane respectively, which is actually the resultant of a group of acting forces, and the acting forces received by the 2 sensing modules 5 are shown in fig. 12.

It is noted that, in this document, relational terms such as "first" and "second," and the like, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. In addition, "front", "rear", "left", "right", "upper" and "lower" in this document are all referred to the placement state shown in the drawings.

Finally, it should be noted that: the above examples are only for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An online braking torque monitoring system, comprising: the system comprises at least two sensing modules and a control module;

each sensing module is vertically arranged between a brake and a support, the top end of each sensing module is connected with the bottom of the brake, the bottom end of each sensing module is connected with the top of the support and is respectively used for bearing pressure and tension between the brake and the support during braking, and strain gauges are arranged on the sensing modules and are used for monitoring pressure or tension data;

the control module is electrically connected with the strain gauge and used for receiving pressure or tension data and acquiring braking torque according to the pressure or tension data.

2. The system for on-line monitoring of braking torque as claimed in claim 1, wherein said sensing module comprises two connection plates and a cylinder disposed between said two connection plates, said two connection plates are respectively connected to said brake and said support, said strain gauge is disposed on said cylinder.

3. The system for on-line monitoring of braking torque as claimed in claim 2, wherein a set of strain gauges is arranged on each side of the cylinder, and a plurality of sets of strain gauges are distributed circumferentially on the outer wall of the cylinder.

4. The on-line braking torque monitoring system according to claim 3, wherein each group of strain gauges includes 2 vertical strain gauges and 2 transverse strain gauges, the 2 vertical strain gauges are arranged in parallel at intervals along the height direction of the cylinder, and the 2 transverse strain gauges are respectively arranged transversely above and below the 2 vertical strain gauges.

5. The on-line braking torque monitoring system according to claim 2, wherein the connecting plate is a rectangular plate with a hole in the middle, and the connecting plate is connected with the brake or the support through a bolt.

6. The on-line braking torque monitoring system according to claim 1, further comprising an alarm module, wherein the alarm module is connected with the control module and used for sending out an alarm signal when the braking torque is abnormal.

7. A method for on-line monitoring of brake torque by using the on-line brake torque monitoring system as claimed in any one of claims 1 to 6, wherein the method comprises:

8. The method for on-line monitoring of braking torque according to claim 7, wherein the braking torque is obtained according to the values of the tension and the pressure by the following formula:

Mm＝N11×L+N9×K；

9. The online brake torque monitoring method according to claim 7, further comprising:

and when the braking torque is abnormal, the control module controls the alarm module to send out an alarm signal.