A variable frequency motor protection device

Abstract

The utility model discloses a kind of variable-frequency motor protection devices, including shaft center compensation mechanism, shaft center compensation mechanism includes fixed shaft, both ends of fixed shaft are fixed with universal joint, the end of universal joint is fixed with flange.The utility model significantly improves the installation adaptability and operating stability of system by shaft center compensation mechanism;Shaft center compensation mechanism adopts the design of fixed shaft and universal joint combination, can effectively compensate the shaft center deviation between motor and overspeed switch, reduce the mechanical stress caused by misalignment or vibration;This design reduces the wear and tear of transmission component, prolongs the service life of device;At the same time, the connecting mode of universal joint and flange ensures the reliability of power transmission, suitable for variable-frequency motor under a variety of working conditions;Compared with traditional rigid connection overspeed protection device, the mechanism shows higher flexibility and stability in complex industrial environment, reduces maintenance frequency and cost, provides reliable guarantee for long-term safe operation of motor.

Description

Technical Field

[0001] This utility model relates to the field of variable frequency motor technology, and in particular to a variable frequency motor protection device. Background Technology

[0002] Overspeed switches, as core components for the protection of variable frequency motors, are widely used in industrial fields such as fans, pumps, and high-speed rotating machinery to prevent motor damage due to overspeed operation. Existing overspeed switches typically employ mechanical centrifugal or electronic sensor designs, triggering power-off or deceleration mechanisms by detecting abnormal speed. Mechanical overspeed switches often include a rotating disc, counterweight, and contact structure. Centrifugal force moves the counterweight, closing or opening the contacts to output a protection signal. This type of switch has a simple structure, is suitable for operation in harsh environments, and offers high reliability.

[0003] However, existing overspeed switches still require connection to the motor shaft and installation via a fixed base in practical applications to ensure power transmission and device stability. However, existing overspeed switches have several shortcomings. First, their connection method typically employs a rigid structure, making it difficult to accommodate shaft misalignment or vibration, leading to mechanical wear and reduced transmission efficiency. Second, the trigger thresholds of overspeed switches are mostly fixed, making it difficult to flexibly adapt to motors with different speed requirements, thus limiting their application range. Furthermore, the bases of existing overspeed switches lack adjustability, making it difficult to adapt to various operating conditions during installation, increasing the complexity of on-site commissioning and maintenance. These deficiencies reduce the protective effect and ease of use of overspeed switches in complex industrial environments. Utility Model Content

[0004] The purpose of this utility model is to address the shortcomings of existing technologies by proposing a variable frequency motor protection device.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A variable frequency motor protection device includes a shaft compensation mechanism. The shaft compensation mechanism includes a fixed shaft, with universal joints fixed at both ends of the fixed shaft. Flanges are fixed at the ends of the universal joints. One end of the shaft compensation mechanism is connected to the power input terminal of an overspeed switch. An adjustable base is provided below the overspeed switch. The adjustable base includes a cylindrical body. A support block is movably and retractably sleeved inside the cylindrical body. A fixed seat is fixed at the bottom of the support block. Several first adjustment holes are vertically arranged on the cylindrical body. Several second adjustment holes are vertically arranged on the support block. The several second adjustment holes correspond to the several first adjustment holes. The first adjustment holes and the second adjustment holes are fixed together by screws and nuts.

[0006] Preferably, the overspeed switch includes an overspeed detection mechanism, which is rotatably disposed inside the inner housing, and an outer housing is fixed to the outside of the inner housing.

[0007] Preferably, the overspeed detection mechanism includes a turntable with a connecting shaft running through its center. The connecting shaft serves as the power input end of the overspeed switch. Three rotating shafts are fixed at the edge of the turntable, and counterweights are rotatably connected to the rotating shafts. The inner side of the counterweights is elastically connected to the turntable via tension springs.

[0008] Preferably, a first fixing block is fixedly provided at the edge of the turntable, and a stationary contact is fixed at the end of the first fixing block. A second fixing block is provided on the counterweight block, and a moving contact is provided on the second fixing block. The stationary contact and the moving contact correspond to each other.

[0009] Preferably, one of the flanges is fixedly connected to the connecting shaft.

[0010] Preferably, the outer shell is fixedly connected to the support block.

[0011] This utility model has the following beneficial effects: 1. This utility model significantly improves the installation adaptability and operational stability of the system through the shaft compensation mechanism. The shaft compensation mechanism adopts a design combining a fixed shaft and a universal joint, which can effectively compensate for the shaft misalignment between the motor and the overspeed switch, reducing mechanical stress caused by misalignment or vibration. This design reduces the wear of transmission components and extends the service life of the device. At the same time, the connection method between the universal joint and the flange ensures the reliability of power transmission and is suitable for variable frequency motors under various working conditions. Compared with traditional rigid connection overspeed protection devices, this mechanism exhibits higher flexibility and stability in complex industrial environments, reduces maintenance frequency and cost, and provides a reliable guarantee for the long-term safe operation of the motor.

[0012] 2. This utility model achieves high-precision overspeed protection through optimized design of the turntable, counterweight, and tension spring. When the motor speed exceeds the limit, the counterweight, under centrifugal force, drives the moving contact to close with the stationary contact, quickly triggering a protection signal and protecting the motor from overspeed damage. This mechanism adopts a mechanical design, which is simple and durable, suitable for stable operation in harsh environments such as high temperature and humidity. Compared to electronic sensor switches, this mechanical design eliminates the need for complex circuitry, reducing failure rates and maintenance costs. Furthermore, the elastic adjustment of the tension spring allows for flexible adaptation to different speed thresholds, improving the device's versatility and protection effectiveness.

[0013] 3. The adjustable base design of this utility model greatly facilitates the installation and maintenance of the device. Through the telescopic structure of the cylinder and support block, combined with multiple sets of adjustment holes and screw fixing methods, users can flexibly adjust the height and position of the device according to actual needs, adapting to different types of motors and installation environments. This adjustability overcomes the limitations of traditional fixed bases, simplifies on-site installation and commissioning, and reduces the difficulty of manual operation. At the same time, the stable connection between the fixed base and the outer shell ensures the overall stability of the device and reduces the impact of vibration during operation. This design significantly improves the versatility and practicality of the device, making it particularly suitable for the application needs of diverse industrial scenarios. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the protective device structure; Figure 2 This is a schematic diagram of the shaft compensation mechanism. Figure 3 Exploded view of the overspeed switch and adjustable base; Figure 4 This is a schematic diagram of the overspeed detection mechanism. Figure 5 for Figure 4 Enlarged view of the local structure at point A in the middle.

[0015] In the diagram: 1. Shaft compensation mechanism; 101. Fixed shaft; 102. Universal joint; 103. Flange; 2. Overspeed switch; 201. Outer shell; 202. Inner shell; 203. Overspeed detection mechanism; 203a. Turntable; 203b. Connecting shaft; 203c. Rotating shaft; 203d. Counterweight; 203e. First fixed block; 203f. Stationary contact; 203g. Moving contact; 203h. Second fixed block; 203i. Tension spring; 3. Adjustable base; 301. Cylinder; 302. First adjusting hole; 303. Screw; 304. Nut; 305. Support block; 306. Second adjusting hole; 307. Fixed seat. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0017] Reference Figure 1-5A variable frequency motor protection device includes a shaft compensation mechanism 1. The shaft compensation mechanism 1 includes a fixed shaft 101. Universal joints 102 are fixed at both ends of the fixed shaft 101. Flanges 103 are fixed at the ends of the universal joints 102. One end of the shaft compensation mechanism 1 is connected to the power input end of an overspeed switch 2. An adjustable base 3 is provided below the overspeed switch 2. The adjustable base 3 includes a cylindrical body 301. A support block 305 is movably and retractably sleeved inside the cylindrical body 301. A fixed seat 307 is fixed at the bottom end of the support block 305. A plurality of first adjustment holes 302 are vertically arranged on the cylindrical body 301. A plurality of second adjustment holes 306 are vertically arranged on the support block 305. The plurality of second adjustment holes 306 correspond to the plurality of first adjustment holes 302. The first adjustment holes 302 and the second adjustment holes 306 are fixed together by screws 303 and nuts 304.

[0018] In this embodiment, overspeed protection and installation adaptation of the motor are achieved through a shaft compensation mechanism 1, an overspeed switch 2, and an adjustable base 3. The fixed shaft 101 in the shaft compensation mechanism 1 cooperates with a universal joint 102, and the flange 103 connects to the power input end of the overspeed switch 2, compensating for shaft misalignment, reducing wear, and ensuring stable power transmission. The overspeed switch 2 detects the rotational speed and triggers the protection mechanism when overspeed occurs. The retractable support block 305 inside the cylindrical body 301 of the adjustable base 3 is fixed with screws 303 and nuts 304 through the first adjustment hole 302 and the second adjustment hole 306. The fixed base 307 ensures stability and adapts to different installation heights and environments. This device has a simple structure, high flexibility, significantly improves installation convenience and operational reliability, and protects the variable frequency motor from overspeed damage.

[0019] In this utility model, the overspeed switch 2 includes an overspeed detection mechanism 203, which is rotatably disposed inside the inner housing 202, and an outer housing 201 is fixed to the outside of the inner housing 202.

[0020] In this embodiment, the overspeed switch 2 includes an overspeed detection mechanism 203, which is rotatably disposed inside the inner housing 202, and an outer housing 201 is fixed to the outside of the inner housing 202.

[0021] In this utility model, the overspeed detection mechanism 203 includes a turntable 203a, a connecting shaft 203b passing through the center of the turntable 203a, the connecting shaft 203b serving as the power input end of the overspeed switch 2, three rotating shafts 203c fixed at the edge of the turntable 203a, a counterweight 203d rotatably connected to the rotating shaft 203c, and the inner side of the counterweight 203d elastically connected to the turntable 203a through a tension spring 203i.

[0022] In this embodiment, the overspeed detection mechanism 203 achieves overspeed detection and protection of the variable frequency motor through the coordinated operation of the turntable 203a, connecting shaft 203b, rotating shaft 203c, counterweight 203d, and tension spring 203i. The connecting shaft 203b passes through the center of the turntable 203a and serves as the power input end of the overspeed switch 2, receiving the rotational power of the motor. The counterweight 203d is connected to the three rotating shafts 203c fixed on the edge of the turntable 203a. The counterweight 203d is elastically connected to the turntable 203a through the tension spring 203i. When the speed is too high, the centrifugal force causes the counterweight 203d to move outward, triggering the protection mechanism. This mechanical design is simple, durable, and adaptable to harsh environments. The elastic adjustment of the tension spring 203i enables flexible speed threshold control, ensuring the accuracy and reliability of overspeed protection and improving the protection effect and service life of the device.

[0023] In this utility model, a first fixing block 203e is fixedly provided at the edge of the turntable 203a, and a stationary contact 203f is fixed at the end of the first fixing block 203e. A second fixing block 203h is provided on the counterweight block 203d, and a moving contact 203g is provided on the second fixing block 203h. The stationary contact 203f and the moving contact 203g correspond to each other.

[0024] In this embodiment, the overspeed detection mechanism 203 achieves precise overspeed protection through a first fixed block 203e on the edge of the turntable 203a, a stationary contact 203f, a second fixed block 203h on the counterweight 203d, and a moving contact 203g. The first fixed block 203e is fixed to the turntable 203a, with a stationary contact 203f at its end, while the second fixed block 203h is located on the counterweight 203d and carries the moving contact 203g. When the speed exceeds the limit, the counterweight 203d is moved outward by centrifugal force, causing the moving contact 203g to contact the stationary contact 203f, triggering a protection signal. This design, through a contact correspondence mechanism, ensures rapid response and reliable circuit control. It has a simple structure and does not require complex electronic components, making it suitable for harsh industrial environments. It improves the sensitivity and stability of overspeed detection and ensures the safe operation of the variable frequency motor.

[0025] In this utility model, one of the flanges 103 is fixedly connected to the connecting shaft 203b.

[0026] In this embodiment, a flange 103 in the shaft compensation mechanism 1 is fixedly connected to the connecting shaft 203b of the overspeed switch 2, realizing efficient power transmission and overall system stability. The flange 103, as the end connecting component of the shaft compensation mechanism 1, is firmly connected to the connecting shaft 203b, ensuring that the rotational power of the motor is stably transmitted to the overspeed detection mechanism 203 through the shaft compensation mechanism 1. This fixed connection design compensates for shaft deviation through the flexibility of the universal joint 102, reducing mechanical stress and wear, while ensuring the reliability of power input. This structure enhances the adaptability of the device under high vibration or complex working conditions, improves the accuracy and durability of overspeed protection, and provides a solid guarantee for the safe operation of the variable frequency motor.

[0027] In this utility model, the outer shell 201 is fixedly connected to the support block 305.

[0028] In this embodiment, the outer shell 201 of the overspeed switch 2 is fixedly connected to the support block 305 of the adjustable base 3, ensuring the overall structural stability and installation reliability of the variable frequency motor protection device. The outer shell 201, as the external protective structure of the overspeed switch 2, is firmly combined with the support block 305, and the stability of the device is further enhanced by the fixing seat 307. This connection method allows the overspeed switch 2 to be stably installed on the adjustable base 3, adapting to the installation requirements of different heights and working conditions, while effectively resisting the impact of vibration during operation. This design improves the durability and installation flexibility of the device, simplifies the on-site commissioning and maintenance process, provides stable structural support for the overspeed protection of the variable frequency motor, and ensures long-term safe operation.

[0029] In operation, the overspeed protection and stable operation of the variable frequency motor are achieved through the coordinated work of the shaft compensation mechanism 1, the overspeed switch 2, and the adjustable base 3. The rotational power of the motor is transmitted to the connecting shaft 203b of the overspeed switch 2 via the fixed shaft 101, universal joint 102, and flange 103 of the shaft compensation mechanism 1. The connecting shaft 203b drives the turntable 203a to rotate. A counterweight 203d is connected to the rotating shaft 203c on the edge of the turntable 203a. The counterweight 203d is elastically connected to the turntable 203a via a tension spring 203i. When the rotational speed exceeds the safety threshold, centrifugal force causes the counterweight 203d to move outward, driving the moving contact 203g on the second fixed block 203h to approach the stationary contact 203f on the first fixed block 203e. After the two contacts, the circuit is closed, triggering a protection signal. Overspeed protection is usually achieved by connecting to an external control system to cut off the motor power supply or reduce the speed. The outer shell 201 and inner shell 202 protect the overspeed detection mechanism 203 and are fixed to the cylinder 301, first adjustment hole 302, second adjustment hole 306, screw 303 and nut 304 of the adjustable base 3 by the support block 305. The fixing seat 307 ensures the overall stability. The adjustable base 3 adapts to the installation height through its telescopic design and compensates for shaft deviation with the universal joint 102 to ensure smooth power transmission and stable operation of the device. This device combines mechanical and electrical components, has a simple structure, responds quickly, is suitable for harsh industrial environments, and ensures the safe operation of the variable frequency motor.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A variable frequency motor protection device, characterized by, The device includes a shaft compensation mechanism (1), which includes a fixed shaft (101). Both ends of the fixed shaft (101) are fixed with universal joints (102), and the ends of the universal joints (102) are fixed with flanges (103). One end of the shaft compensation mechanism (1) is connected to the power input end of an overspeed switch (2). An adjustable base (3) is provided below the overspeed switch (2). The adjustable base (3) includes a cylindrical body (301), and the interior of the cylindrical body (301) is a downwardly retractable movable sleeve. A support block (305) is attached, and a fixing seat (307) is fixed at the bottom of the support block (305). A plurality of first adjustment holes (302) are vertically arranged on the cylinder (301), and a plurality of second adjustment holes (306) are vertically arranged on the support block (305). The plurality of second adjustment holes (306) correspond to the plurality of first adjustment holes (302). The first adjustment holes (302) and the second adjustment holes (306) are fixed together by screws (303) and nuts (304).

2. A variable frequency motor protection device according to claim 1, wherein, The overspeed switch (2) includes an overspeed detection mechanism (203), which is rotatably disposed inside the inner housing (202), and an outer housing (201) is fixed outside the inner housing (202).

3. A variable frequency motor protection device according to claim 2, wherein, The overspeed detection mechanism (203) includes a turntable (203a), with a connecting shaft (203b) passing through the center of the turntable (203a). The connecting shaft (203b) serves as the power input end of the overspeed switch (2). Three rotating shafts (203c) are fixed at the edge of the turntable (203a). A counterweight (203d) is rotatably connected to the rotating shaft (203c). The inner side of the counterweight (203d) is elastically connected to the turntable (203a) through a tension spring (203i).

4. A variable frequency motor protection device according to claim 3, characterized in that, A first fixing block (203e) is fixedly provided at the edge of the turntable (203a), and a stationary contact (203f) is fixed at the end of the first fixing block (203e). A second fixing block (203h) is provided on the counterweight block (203d), and a moving contact (203g) is provided on the second fixing block (203h). The stationary contact (203f) and the moving contact (203g) correspond to each other.

5. A variable frequency motor protection device according to claim 3, characterized in that, One of the flanges (103) is fixedly connected to the connecting shaft (203b).

6. A variable frequency motor protection device according to claim 2, characterized in that, The outer shell (201) is fixedly connected to the support block (305).

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