Overload detection device suitable for motor transmission

Abstract

The utility model discloses an overload detection device suitable for motor transmission, which comprises a driving unit, a bidirectional force sensor and a signal processing unit, and is characterized in that the driving unit comprises a power output shaft connected with an equipment main body and a power source for driving the power output shaft; one end of the bidirectional force sensor is connected with a stress structure of a power source through a first force transmission mechanism, the other end of the bidirectional force sensor is connected with an equipment body through a second force transmission mechanism, and the signal processing unit is configured to generate an overload signal based on a force signal output by the bidirectional force sensor. Two-way detection of tension and pressure is supported through the two-way force sensor, jamming of the cargo carrying table can be monitored, jamming of the balance weight can also be detected, and the device is suitable for various complex working conditions.

Description

Technical Field

[0001] This utility model relates to the field of intelligent logistics technology, specifically to an overload detection device suitable for motor drives. Background Technology

[0002] Every piece of equipment has a maximum rated load as an essential parameter, which is especially important for lifting equipment. In actual use, there is a dangerous situation where operators may place goods weighing more than the maximum rated load into the equipment and make it run. In addition, equipment equipped with lifting functions may jam during lifting operations due to external interference or loose goods, which is also very dangerous.

[0003] Currently, there are two common solutions for overload detection devices: one is to design a spring structure at the lifting point in conjunction with a lever switch. When the lifted object is overloaded, the spring deforms elastically, triggering the lever switch to send an overload signal. However, this type of spring-structured overload detection device has significant drawbacks. The spring deformation is large, which reduces positioning accuracy in actual use and is prone to "non-triggered" or "false-triggered" situations. Furthermore, when the same equipment has multiple lifting points, multiple overload detection devices are required, which leads to unstable signals and is extremely difficult to calibrate. Additionally, the device is installed at the lifting point, making daily maintenance and spare parts replacement difficult.

[0004] Another approach involves designing a pin with a built-in strain gauge and integrated PCB board at the lifting point. When the lifted object is overloaded, the strain gauge inside the pin undergoes slight elastic deformation, affecting the internal current. When the current reaches a set value, an overload signal is emitted. However, in this design, the strain gauge pin at the lifting point has a fixed force direction. If a component on the lifting rope gets stuck (such as when the counterweight is rising), it cannot be detected. Similarly, multiple devices are required in multi-lifting-point equipment, leading to signal instability, calibration difficulties, and the inconvenience of installing them at the lifting points for routine maintenance and spare parts replacement.

[0005] Therefore, how to overcome the shortcomings of the existing technology mentioned above has become the subject of this application. Utility Model Content

[0006] In view of this, the purpose of this utility model is to provide an overload detection device suitable for motor drives.

[0007] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0008] An overload detection device suitable for motor drives, comprising:

[0009] A drive unit, comprising a power output shaft connected to the main body of the device and a power source for driving the power output shaft;

[0010] A bidirectional force sensor, one end of which is connected to the force-receiving structure of the power source through a first force transmission mechanism, and the other end of which is connected to the main body of the device through a second force transmission mechanism;

[0011] The signal processing unit is configured to generate an overload signal based on the force signal output by the bidirectional force sensor.

[0012] Furthermore, the power source includes a motor, and the power output shaft is the drive shaft of the motor.

[0013] Furthermore, the first force transmission mechanism includes a first torque arm connecting rod and a first torque arm mounting base. The first torque arm mounting base is mounted to the housing of the motor by a first fixing bolt. One end of the first torque arm connecting rod is connected to the first torque arm mounting base, and the other end is connected to the input end of the bidirectional force sensor.

[0014] Furthermore, the second force transmission mechanism includes a second torque arm connecting rod and a second torque arm mounting seat. The second torque arm mounting seat is mounted to the main body of the equipment by a second fixing bolt. One end of the second torque arm connecting rod is connected to the second torque arm mounting seat, and the other end is connected to the output end of the bidirectional force sensor.

[0015] Furthermore, the drive shaft is mounted on a seated bearing, which is mounted on the main body of the equipment by a third fixing bolt.

[0016] Furthermore, a timing pulley is mounted on the drive shaft.

[0017] Furthermore, the signal processing unit includes a threshold comparison module and a determination output module. The threshold comparison module is configured to compare the force signal with preset tension thresholds and pressure thresholds. The determination output module is configured to generate an overload signal when the force signal exceeds any threshold.

[0018] Furthermore, the bidirectional force sensor is a strain sensor, comprising an elastomer and a strain gauge attached to the surface of the elastomer, wherein the strain gauge is configured to convert the deformation of the elastomer into an electrical signal.

[0019] Furthermore, the bidirectional force sensor, the first force transmission mechanism, and the second force transmission mechanism are integrated within the visible range of the maintenance platform on the side of the motor.

[0020] Compared with existing technologies, the advantages of this invention are as follows: Overload detection via a bidirectional force sensor avoids problems caused by mechanical structural deformation, thus ensuring equipment operating accuracy and effectively preventing "non-triggering" or "false triggering" phenomena. This ensures accurate and reliable detection. The bidirectional force sensor supports both tensile and compressive force detection, enabling it to detect both loading platform jamming and counterweight jamming, making it suitable for various complex working conditions. Furthermore, the overload detection device is installed at the motor location, allowing for simultaneous detection during motor inspection on the maintenance platform, greatly simplifying the maintenance process, reducing maintenance costs, and improving equipment operation and maintenance efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Appendix Figure 1 This is a schematic diagram of the structure of an embodiment of this application.

[0023] Explanation of reference numerals and components in the accompanying drawings:

[0024] 1. Drive unit; 11. Motor; 12. Drive shaft; 2. Bidirectional force sensor; 3. First torque arm connecting rod; 4. First torque arm mounting seat; 5. First fixing bolt; 6. Second torque arm connecting rod; 7. Second torque arm mounting seat; 8. Second fixing bolt; 9. Bearing with seat; 10. Third fixing bolt; 13. Synchronous pulley. Detailed Implementation

[0025] The technical solution of this utility model will now be clearly and completely described through specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0026] See appendix Figure 1 As shown, an overload detection device suitable for motor drives includes a drive unit 1, a bidirectional force sensor 2, and a signal processing unit. The drive unit 1 includes a power output shaft connected to the main body of the device and a power source that drives the power output shaft. One end of the bidirectional force sensor is connected to the force-receiving structure of the power source through a first force transmission mechanism, and the other end is connected to the main body of the device through a second force transmission mechanism. The signal processing unit is configured to generate an overload signal based on the force signal output by the bidirectional force sensor.

[0027] The power source includes a motor 11, and the power output shaft is the drive shaft 12 of the motor 11. The first force transmission mechanism includes a first torque arm connecting rod 3 and a first torque arm mounting seat 4. The first torque arm mounting seat 4 is mounted to the housing of the motor 11 by a first fixing bolt 5. One end of the first torque arm connecting rod 3 is connected to the first torque arm mounting seat 4, and the other end is connected to the input end of the bidirectional force sensor 2. The second force transmission mechanism includes a second torque arm connecting rod 6 and a second torque arm mounting seat 7. The second torque arm mounting seat 7 is mounted to the main body of the equipment by a second fixing bolt 8. One end of the second torque arm connecting rod 6 is connected to the second torque arm mounting seat 7, and the other end is connected to the output end of the bidirectional force sensor 2. The motor 11 outputs torque through the drive shaft 12 to drive the equipment. Preferably, the first torque arm mounting base 4 is rigidly fixed to the motor 11 housing by the first fixing bolt 5. One end of the first torque arm connecting rod 3 is hinged to the first torque arm mounting base 4, and the other end is connected to the input end of the bidirectional force sensor 2, forming a tension transmission path from the motor housing to the first torque arm connecting rod 3 and then to the bidirectional force sensor 2. The second torque arm mounting base 7 is fixed to the equipment body by the second fixing bolt 8. One end of the second torque arm connecting rod 6 is hinged to the second torque arm mounting base 7, and the other end is connected to the output end of the bidirectional force sensor 2, forming a pressure transmission path from the bidirectional force sensor 2 to the second torque arm connecting rod and then to the equipment body.

[0028] Preferably, the bidirectional force sensor 2 is a strain gauge sensor, comprising an elastic body and a strain gauge attached to the surface of the elastic body. The strain gauge is configured to convert the deformation of the elastic body into an electrical signal. The elastic body acts as a force-deformation conversion element, and its deformation is linearly related to the external load. The strain gauge, attached to the surface of the elastic body, is made of a metal resistance wire or a semiconductor material. When the elastic body deforms, the strain gauge is stretched or compressed, causing a change in its resistance value; the resistance increases during stretching and decreases during compression, i.e., the strain effect.

[0029] When the equipment is operating normally, the torque of motor 11 is transmitted to the load through drive shaft 12. At this time, the housing of motor 11 only bears its own torque reaction force, and the bidirectional force sensor 2 is in a balanced state. Tensile overload: If the loading platform cannot move due to overloading or jamming, the continued output torque of motor 11 will cause the drive shaft 12 to be obstructed, and the torque arm will generate abnormal tensile force in the tensile direction. This tensile force is transmitted to the input end of bidirectional force sensor 2 through the first torque arm connecting rod 3. The strain gauge inside bidirectional force sensor 2 deforms, causing a change in resistance value, and outputting an electrical signal proportional to the tensile force. Pressure overload: If the counterweight system cannot fall back due to jamming, motor 11 needs to output torque in the reverse direction to overcome the resistance. The torque arm generates abnormal pressure in the compression direction. This pressure is transmitted to the output end of bidirectional force sensor 2 through the second torque arm connecting rod 6. Bidirectional force sensor 2 detects the pressure signal through reverse deformation and outputs an electrical signal proportional to the pressure. By using the same sensor to achieve bidirectional monitoring of tension and pressure, in tension mode, it can capture abnormal tension in the motor torque arm in real time when the loading platform jams, avoiding safety hazards caused by overweight cargo or lifting jams. In pressure mode, it accurately monitors the reverse pressure generated when the counterweight system jams, solving the deficiency of traditional one-way detection schemes that cannot identify reverse loads, and covering the overload monitoring needs of lifting equipment under all operating conditions.

[0030] Force transmission path:

[0031] Tension scenario: From the housing of motor 11 to the first torque arm mounting seat 4 to the first torque arm connecting rod 3 to the input end of bidirectional force sensor 2 to the sensor elastomer, stretched to the output end of sensor to the second torque arm connecting rod 6 to the second torque arm mounting seat 7 to the main body of equipment.

[0032] Pressure scenario: From the motor housing to the first torque arm mounting seat 4 to the first torque arm connecting rod 3 to the input end of the bidirectional force sensor 2 to the sensor elastomer compression to the sensor output end to the second torque arm connecting rod 6 to the second torque arm mounting seat 7 to the main body of the equipment.

[0033] Preferably, the signal processing unit in this embodiment includes a threshold comparison module and a determination output module. The threshold comparison module is configured to compare the force signal with a preset tension threshold and a pressure threshold. The determination output module is configured to generate an overload signal when the force signal exceeds either threshold.

[0034] Preferred options are listed in the appendix. Figure 1 As shown, in this embodiment, the rigid connection between the seated bearing 9 and the main body of the equipment achieves stable support and torque transmission of the drive shaft 12. The seated bearing 9 is installed on the main body of the equipment by the third fixing bolt 10. The combination of the seated bearing 9 and the third fixing bolt 10 constitutes the rigid support system of the drive shaft 12. Its core function is to ensure the stable transmission of the torque of the motor 11, suppress vibration, and facilitate maintenance.

[0035] Preferred options are listed in the appendix. Figure 1 As shown, this embodiment integrates a synchronous pulley 13 on the drive shaft 12 to achieve efficient transmission of the motor 11 torque and coordinated overload protection. The synchronous pulley 13 transmits the torque output by the motor 11 to the loading platform or counterweight system.

[0036] Preferred options are listed in the appendix. Figure 1 As shown, in this embodiment, the first torsion arm link 3 and the second torsion arm link 6 are of equal length, and their connection points with the bidirectional force sensor 2 are located on the same force axis. The equal-length link and coaxial design, through mechanical symmetry and structural constraints, eliminate non-axial force interference at its source, forming the basis for achieving high-precision bidirectional force detection. This design not only improves the reliability of overload detection but also reduces manufacturing and maintenance costs through a standardized structure, making it particularly suitable for industrial scenarios with high requirements for accuracy and stability.

[0037] Preferred options are listed in the appendix. Figure 1 As shown, in this embodiment, the bidirectional force sensor 2, the first torque arm link 3, and the second torque arm link 6 are integrated within the visible range of the maintenance platform on the side of the motor 11.

[0038] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An overload detection device suitable for use in motor drives, characterized by, include: A drive unit, comprising a power output shaft connected to the main body of the device and a power source for driving the power output shaft; A bidirectional force sensor, one end of which is connected to the force-receiving structure of the power source through a first force transmission mechanism, and the other end of which is connected to the main body of the device through a second force transmission mechanism; The signal processing unit is configured to generate an overload signal based on the force signal output by the bidirectional force sensor.

2. An overload detection device for motor drives according to claim 1, wherein, The power source includes a motor, and the power output shaft is the drive shaft of the motor.

3. An overload detection device for motor drives according to claim 2, wherein, The first force transmission mechanism includes a first torque arm connecting rod and a first torque arm mounting base. The first torque arm mounting base is mounted to the housing of the motor by a first fixing bolt. One end of the first torque arm connecting rod is connected to the first torque arm mounting base, and the other end is connected to the input end of the bidirectional force sensor.

4. An overload detection device for motor drives as recited in claim 2, wherein, The second force transmission mechanism includes a second torque arm connecting rod and a second torque arm mounting base. The second torque arm mounting base is mounted on the main body of the equipment by a second fixing bolt. One end of the second torque arm connecting rod is connected to the second torque arm mounting base, and the other end is connected to the output end of the bidirectional force sensor.

5. An overload detection device for motor drives as recited in claim 2, wherein, The drive shaft is mounted on a seated bearing, which is mounted on the main body of the equipment by a third fixing bolt.

6. An overload detection device for motor drives as recited in claim 2, wherein, A timing pulley is mounted on the drive shaft.

7. An overload detection device for motor drives as recited in claim 2, wherein, The signal processing unit includes a threshold comparison module and a determination output module. The threshold comparison module is configured to compare the force signal with a preset tensile force threshold and a pressure threshold. The determination output module is configured to generate an overload signal when the force signal exceeds any threshold.

8. An overload detection device for motor drives as recited in claim 2, wherein, The bidirectional force sensor is a strain sensor, comprising an elastomer and a strain gauge attached to the surface of the elastomer, wherein the strain gauge is configured to convert the deformation of the elastomer into an electrical signal.

9. An overload detection device for motor drives as recited in claim 2, wherein, The bidirectional force sensor, the first force transmission mechanism, and the second force transmission mechanism are integrated within the visible range of the maintenance platform on the side of the motor.

Images