Eddy current buffer device and electric shovel including the buffer device

Abstract

The present invention relates to the technical field of mining equipment, and particularly relates to an eddy current buffer device and an electric shovel including the buffer device. The eddy current buffer device includes a base, a main shaft, a rocker arm, a connecting rod, an acceleration mechanism, and an eddy current generating mechanism; the main shaft is assembled on the base, the rocker arm is fixedly connected to the main shaft and can rotate about the axis with the main shaft; the connecting rod is hinged to the rocker arm; the acceleration mechanism can amplify the rotational speed of the main shaft and transmit it to the eddy current generating mechanism; the eddy current generating mechanism can generate a damping force on the fast end. By amplifying the rotational speed of the main shaft through the acceleration mechanism and then transmitting it, the damping torque of the eddy current generating mechanism is greatly increased, realizing effective buffering and vibration reduction with fewer magnets and smaller-sized conductors, and improving the practicability and economy of the eddy current buffer device.

Description

Technical Field

[0001] The present invention relates to the technical field of mining equipment, and particularly to an eddy current buffer device and an electric shovel including the buffer device. Background Art

[0002] An electric shovel is the main excavation equipment for various modern open-pit mines. During operation, the bucket door is opened for unloading. The electric shovel has a large overall weight. When the bucket door is closed after unloading, the bucket door will generate a great impact force on the bucket body, resulting in easy damage to the bucket body. Therefore, a buffer and vibration damping device needs to be added to slow down this impact force.

[0003] The traditional buffer devices for electric shovels are mechanical buffers and hydraulic buffers. The mechanical buffer is similar to an automobile brake, which makes the acting body rub against the friction plate to convert kinetic energy into heat energy to absorb and convert the impact load energy. Its service life is short. During operation, as the friction plate wears, it is necessary to frequently adjust and increase the pre-tightening force of its compression spring. If the adjustment is improper, it will lead to poor buffer effect of the bucket door, resulting in shortened service life of the electric shovel, and high maintenance and replacement costs; the hydraulic buffer relies on the internal viscous fluid to generate damping to buffer and decelerate the acting body, and there are problems of liquid leakage and sealing. Once liquid leakage occurs, the buffer will fail, and the working environment temperature of the viscous fluid is about -20°C at the lowest, and it cannot be applied to extremely low temperature working environments (for example, in some mining areas in the north of China, the lowest temperature in winter can reach -45°C).

[0004] The eddy current buffer uses eddy current damping technology to produce a buffer effect, that is, magnetic damping is generated by the relative movement of a conductor plate and a permanent magnet, and is transmitted to the bucket door through a connecting component to inhibit the movement of the bucket door and achieve the buffer purpose. For example, the applicant's team's prior invention patent with the application number 202011033221.0 discloses an eddy current curved arm buffer. The eddy current buffer neither relies on friction for energy consumption, has a stable damping force without adjustment, and has a good buffer effect, nor has a working fluid, so there are no problems of liquid leakage and sealing, and it can work in an extremely low temperature environment (-60°C). Compared with the above two traditional buffers, it has obvious advantages such as high reliability and good durability. However, since the weight of the bucket door is often not less than 3 tons, for the eddy current buffer to generate a damping torque that can effectively inhibit the movement of the bucket door, it requires a large diameter, hundreds of permanent magnets and conductors of corresponding sizes. The large diameter brings inconvenience in installation and use, and the permanent magnet material often uses neodymium iron boron, and the conductor material often uses high-conductivity metals such as copper and aluminum, all of which are expensive. Summary of the Invention

[0005] The object of the present invention is to provide an eddy current buffer device, aiming at the problems of the huge volume and high cost of the existing eddy current buffer device. By arranging an accelerator between the eddy current generating mechanism and the rocker arm, the rotation speed of the rocker arm is amplified and then transmitted to the eddy current generating mechanism, reducing the performance requirements for the eddy current generating mechanism and facilitating the improvement of the practicability and economy of the eddy current buffer device.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] An eddy current buffer device includes a base, a main shaft, a rocker arm, a connecting rod, an acceleration mechanism and an eddy current generating mechanism; the main shaft is assembled on the base; the rocker arm is fixedly connected to the main shaft and can rotate about the axis with the main shaft; the connecting rod is hinged to the rocker arm; the slow end of the acceleration mechanism is connected to the main shaft, and the fast end of the acceleration mechanism is connected to the eddy current generating mechanism; the acceleration mechanism can amplify the rotation speed of the main shaft and then transmit it to the eddy current generating mechanism; the eddy current generating mechanism can generate a damping force on the fast end.

[0008] The rotation speed of the main shaft is amplified by the acceleration mechanism and then transmitted to the eddy current generating mechanism. By utilizing the velocity correlation of the eddy current damping force, that is, the faster the relative movement speed between the conductor and the magnet, the greater the generated eddy current damping force and the greater the kinetic energy dissipation power, the damping torque is greatly increased, and effective buffering and vibration reduction can be achieved with fewer magnets and smaller-sized conductors, improving the practicability and economy of the eddy current buffer device.

[0009] As a preferred solution of the present invention, the acceleration mechanism is a planetary gear accelerator. The planetary gear accelerator is compact in space and suitable for installation.

[0010] As a preferred solution of the present invention, the eddy current generating mechanism includes a magnet, a conductor and a support frame; the support frame is connected to the fast end and can rotate with the fast end, and one of the magnet and the conductor is connected to the support frame; the rotation of the support frame can cause the magnet and the conductor to cut the magnetic force lines and generate a damping force.

[0011] As a preferred solution of the present invention, the conductor is a conductor cylinder, and the magnet includes a plurality of magnetic blocks; the conductor cylinder is sleeved on the support frame; the plurality of magnetic blocks are located between the conductor cylinder and the support frame and are connected to the support frame. The conductor is fixed on the base, and the fast end of the accelerator is connected to the support frame, driving the support frame and the magnet to rotate relative to the conductor, and generating a large eddy current damping torque by quickly cutting the magnetic induction lines.

[0012] As a preferred embodiment of the present invention, the axis of the main shaft is point A, the center of the hinge point of the connecting rod and the rocker arm is point B, and the distance between point A and point B is a; the end of the connecting rod away from the rocker arm has a bucket hinge point for hinging with the bucket door, and the center of the bucket hinge point is point C, and the distance from point B to point C is b; (b / a) ≥ 1.4. Under the condition of meeting the assembly process and no interference during movement, a takes the minimum value.

[0013] As a preferred embodiment of the present invention, the speed ratio of the acceleration mechanism is 3 - 10 times, preferably 4 - 6 times.

[0014] The greater the speed ratio of the acceleration mechanism, the fewer the number of magnets in the eddy current generating device, but the higher the cost of the accelerator. The increase in the cost of the acceleration mechanism and the decrease in the cost of the eddy current generating mechanism reach a balance when the speed ratio is 4 - 6. At this time, the total cost reduction of the two reaches the maximum value. The costs of the rocker arm and the connecting rod are less affected by (b / a). By changing the value of (b / a), the speed ratio can be further increased without changing the acceleration mechanism. Within the range of (b / a) ≥ 1.4, when the bucket door rotates around the rotation point of the bucket body, the rotation speed of the bucket door can be magnified by more than 2 times and then transmitted to the main shaft; the local rotation speed can be magnified by more than 5 times, that is, through the length ratio of the connecting rod and the rocker arm, the eddy current damping coefficient is magnified by more than 4 times, up to more than 25 times.

[0015] As a preferred embodiment of the present invention, the rocker arm and the main shaft are connected by a force - transmitting component; the force - transmitting component is a flat - key mating structure, a spline - key mating structure or a one - way clutch.

[0016] As a preferred embodiment of the present invention, the main shaft and the base are connected by a radial bearing.

[0017] An electric shovel, comprising a bucket body and a bucket door, including the eddy current buffer device as described above, the base is connected to the bucket body, and the end of the connecting rod away from the rocker arm is hinged to the bucket door.

[0018] As a preferred embodiment of the present invention, the axis of the main shaft is point A, the center of the hinge point of the connecting rod and the rocker arm is point B, the center of the hinge point of the connecting rod and the bucket door is point C, and the center of the hinge point of the bucket door and the bucket body is point D; the distance between point A and point B is a, the distance from point B to point C is b, the distance between point C and point D is c, and the distance between point A and point D is d; the line segment a, the line segment b, the line segment c, and the line segment d form a planar four - bar mechanism.

[0019] In summary, due to the adoption of the above - mentioned technical solutions, the beneficial effects of the present invention are:

[0020] 1. The eddy current buffer device of the present invention amplifies the rotation speed of the main shaft through an acceleration mechanism and then transmits it to the eddy current generating mechanism, and utilizes the speed correlation of the eddy current damping force, that is, the faster the relative movement speed of the conductor and the magnet, the greater the eddy current damping force generated, the greater the kinetic energy dissipation power, and the damping torque is greatly improved, so that effective buffering and vibration reduction can be achieved with fewer magnets and smaller-sized conductors, thereby improving the practicality and economy of the eddy current buffer device.

[0021] 2. The eddy current buffer device of the present invention further improves the speed ratio by making the length ratio of the connecting rod and the rocker arm within the range of (b / a)≥1.4. When the bucket door rotates around the bucket body, the speed of the bucket door can be amplified by more than 2 times and then transmitted to the main shaft; the local speed can be amplified by more than 5 times. In conjunction with the acceleration mechanism, the cost of the eddy current generating mechanism can be effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the eddy current buffer device in use state according to Example 1 of the present invention.

[0023] Figure 2 It is a schematic diagram of the structure of the eddy current buffer device of Example 1 of the present invention.

[0024] Figure 3 It is a schematic diagram of the structure of the eddy current buffer device (marked with distance) according to Example 1 of the present invention.

[0025] Figure 4 It is a schematic diagram of the left view structure of the eddy current buffer device of Example 1 of the present invention.

[0026] Figure 5 yes Figure 4 Schematic diagram of the structure after the local section at box O.

[0027] Figure 6 yes Figure 5 Schematic diagram of the enlarged view at circle A.

[0028] Figure 7 It is a schematic diagram of an exploded view of the acceleration mechanism and the eddy current generating mechanism of Example 1 of the present invention.

[0029] Figure 8 It is a schematic diagram of the partial cross-sectional structure of the eddy current buffer device of Example 2 of the present invention.

[0030] Figure 9 These are the test results for different values of b / a in Test Example 1.

[0031] Icon: 100- bucket door; 200- bucket body; 201- connection part;

[0032] 1 - Connecting rod; 2 - Rocker arm; 3 - Base; 4 - Main shaft; 5 - Acceleration mechanism; 51 - Slow end; 52 - Fast end; 6 - Eddy current generating mechanism; 61 - Support frame; 62 - Magnet block; 63 - Conductor cylinder; 7 - Radial bearing; 8 - Force transmission component. Detailed implementation mode

[0033] The present invention will be described in detail below with reference to the accompanying drawings.

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] Embodiment 1

[0036] An eddy current buffer device, as Figure 1 , Figure 2 shown, includes a base 3, a main shaft 4, a rocker arm 2, a connecting rod 1, an acceleration mechanism 5 and an eddy current generating mechanism 6; the main shaft 4 is assembled on the base 3 and can rotate about the axis with the main shaft 4; the rocker arm 2 is fixedly connected to the main shaft 4 and can rotate about the axis with the main shaft 4; the connecting rod 1 is hinged to the rocker arm 2; the acceleration mechanism 5 and the eddy current generating mechanism 6 are both fixedly connected to the base 3; the slow end of the acceleration mechanism 5 is connected to the main shaft 4, and the fast end of the acceleration mechanism 5 is connected to the eddy current generating mechanism 6; the acceleration mechanism 5 can amplify the rotational speed of the main shaft 4 and transmit it to the eddy current generating mechanism 6; the eddy current generating mechanism 6 can generate a damping force on the fast end.

[0037] As Figure 3 shown, the axis center of the main shaft is point A, the center of the hinge point of the connecting rod 1 and the rocker arm 2 is point B, and the distance between point A and point B is a; the end of the connecting rod 1 away from the rocker arm 2 has a bucket hinge point for hinging with the bucket door, and the center of the bucket hinge point is point C, and the distance from point B to point C is b; (b / a) ≥ 1.4. Under the condition of meeting the assembly process and no interference during movement, a takes the minimum value. The axis center of the main shaft 4 is point A, the center of the hinge point of the connecting rod 1 and the rocker arm 2 is point B, the center of the hinge point of the connecting rod 1 and the bucket door 100 is point C, and the center of the hinge point of the bucket door 100 and the bucket body 200 is point D; the distance between point A and point B is a, the distance from point B to point C is b, the distance between point C and point D is c, and the distance between point A and point D is d; the line segment a, the line segment b, the line segment c and the line segment d form a planar four-bar mechanism.

[0038] As Figure 4 , Figure 5 andFigure 6 As shown, a force transmission component 8 is used to connect the rocker arm 2 and the main shaft 4; the force transmission component 8 is a flat key mating structure, a spline mating structure or a one-way clutch. Different designs can be made according to different application scenarios. If connection structures such as flat key mating or spline mating are adopted, the rocker arm 2 and the main shaft 4 always remain relatively stationary, and the bucket door will be subjected to the eddy current damping torque during both the opening and closing processes; if the force transmission component 8 uses a one-way clutch, it can only be driven in a single rotation direction. By setting the installation direction, it can be realized that the bucket door is not affected by the damping force during opening and is subjected to the eddy current damping torque during closing.

[0039] The main shaft 4 and the base 3 are connected by a radial bearing 7. The radial bearing bears the radial load and improves the force-bearing condition of the main shaft 4. A cylindrical roller bearing is preferably used.

[0040] As Figure 7 shown, the acceleration mechanism 5 is a planetary gear accelerator. The planetary gear accelerator is space-compact and suitable for installation. The speed ratio of the acceleration mechanism is 3 - 10 times, and in the preferred solution, the speed ratio of the acceleration mechanism is 4 - 6 times.

[0041] The eddy current generating mechanism 6 includes a magnet, a conductor and a support frame 61; the support frame 61 is connected to the fast end 52 and can rotate with the fast end 52. One of the magnet and the conductor is connected to the support frame 61; the rotation of the support frame 61 can make the magnet and the conductor perform a magnetic field line cutting movement to generate a damping force. Specifically, as Figure 7 shown, the conductor is a conductor cylinder 63, and the magnet includes a plurality of magnetic blocks 62; the conductor cylinder 63 is sleeved on the support frame 61; a plurality of the magnetic blocks 62 are located between the conductor cylinder 63 and the support frame 61, and the magnetic blocks 62 are fixedly connected to the support frame 61. The conductor cylinder 63 is fixed on the base, and the fast end 52 of the accelerator is connected to the support frame 61, driving the support frame 61 and the magnet and the conductor to rotate relative to each other, generating a large eddy current damping torque by quickly cutting the magnetic induction lines.

[0042] After the rotational speed is amplified by two levels through the planar four-bar mechanism and the acceleration mechanism, the number of magnetic steels required to generate an eddy current damping torque that can effectively buffer the bucket door can be reduced to more than one-tenth of the original, and the dimensions and scales of the corresponding conductor cylinder and other components can also be greatly reduced, greatly reducing the manufacturing cost of the eddy current buffer and effectively improving the practicability and economy of applying the eddy current buffer to replace the traditional buffer in the buffer and vibration reduction of the electric shovel bucket door.

[0043] Embodiment 2

[0044] The difference between this embodiment and Embodiment 1 is that, as Figure 8As shown in the figure, the structure of the base 3 is adjusted, the length of the main shaft 4 is shortened, the rocker arm 2 is set to be bent, and the distances between the acceleration mechanism 5 and the eddy current generating mechanism 6 and the rocker arm 2 are shortened. The device structure is more compact, which is conducive to cost reduction.

[0045] Embodiment 3

[0046] An electric shovel, return to Figure 1 , including a bucket body 200 and a bucket door 100, further including the eddy current buffer device as described in Embodiment 1 or Embodiment 2. The base 3 is connected to the bucket body 200 through a connecting portion 201 of the bucket body 200, and one end of the connecting rod 1 far from the rocker arm 2 is hinged to the bucket door 100.

[0047] Test Example 1

[0048] During the design process of the planar four-bar mechanism, as Figure 3 shown, since the sizes of the electric shovel bucket body and the bucket door are often determined, that is, the lengths of d and c are fixed values. Therefore, when designing, it is mainly necessary to determine the lengths of a and b, that is, the center hole distances at both ends of the rocker arm 2 and the connecting rod 1. Under the condition of meeting the assembly process requirements, by reducing the length of a, the overall increase of the speed amplification ratio (the ratio of the rotation speed ω a of the rocker arm 2 rotating around point A to the rotation speed ω c of the bucket door rotating around point D) can be achieved, and by adjusting the size of b / a, the trend of the speed amplification ratio changing with the included angle γ between the bucket door and the bucket body can be adjusted.

[0049] Taking a certain electric shovel as an example, c = 494 mm, d = 557 mm, and three four-bar structure design schemes are taken:

[0050] Scheme 1, a = 550 mm, b = 750 mm; b / a = 1.364;

[0051] Scheme 2, a = 400 mm, b = 750 mm; b / a = 1.875;

[0052] Scheme 3, a = 400 mm, b = 600 mm. b / a = 1.5;

[0053] The curves of the rotation speeds of the rocker arm 2 and the bucket door changing with the included angle γ in each scheme are shown in Figure 9 , ω c is the rotation speed of the bucket door, ω a1 , ω a2 , ω a3They are the rotation speeds of the rocker arm 2 in schemes 1, 2 and 3 respectively. At this time, the angle γ is reduced from 90° to 0°, simulating the closing process of the bucket door. Through design, the average rotation speed can be amplified by more than 2 times, and the local rotation speed can be amplified by more than 5 times. Correspondingly, the eddy current damping coefficient is amplified by more than 4 times and more than 25 times, respectively. In the present invention, it is preferred that a takes the minimum value under the condition that there will be no interference during assembly process and movement, and b / a is not less than 1.4.

[0054] When the speed ratio of the accelerator is 3-10 times, the average speed of the rocker arm 2 rotating around point A can be achieved by controlling the size ratio of the connecting rod and the rocker arm to (b / a) ≥ 1.4. The average speed of the gate rotating around point D The ratio of The comprehensive speed ratio of the accelerator and the four-bar mechanism is 6 to 20 times or more.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An eddy current buffer device, characterized in that, It includes a base (3), a main shaft (4), a rocker arm (2), a connecting rod (1), an acceleration mechanism (5) and an eddy current generating mechanism (6); The main shaft (4) is assembled on the base (3); The rocker arm (2) is fixedly connected to the main shaft (4) and can rotate about the axis with the main shaft (4); The connecting rod (1) is hinged to the rocker arm (2); The slow end of the acceleration mechanism (5) is connected to the main shaft (4), and the fast end of the acceleration mechanism (5) is connected to the eddy current generating mechanism (6); The acceleration mechanism (5) can amplify the rotational speed of the main shaft (4) and transmit it to the eddy current generating mechanism (6); The eddy current generating mechanism (6) can generate a damping force on the fast end; The acceleration mechanism (5) is a planetary gear accelerator; The axis center of the main shaft is point A, the center of the hinge point of the connecting rod and the rocker arm is point B, and the distance between point A and point B is a; the end of the connecting rod far from the rocker arm has a bucket hinge point for hinging with the bucket door, and the center of the bucket hinge point is point C, and the distance from point B to point C is b; (b / a) ≥ 1.4; Under the condition of meeting the assembly process and no interference during movement, a takes the minimum value; The speed ratio of the acceleration mechanism (5) is 3 - 10 times.

2. The eddy current buffer device according to claim 1, wherein The eddy current generating mechanism includes a magnet, a conductor and a support frame; the support frame is connected to the fast end and can rotate with the fast end, and one of the magnet and the conductor is connected to the support frame; the rotation of the support frame can make the magnet and the conductor perform a magnetic field line cutting movement to generate a damping force.

3. The eddy current buffer device according to claim 2, characterized in that, The conductor is a conductor cylinder (63), and the magnet includes several magnetic blocks (62); the conductor cylinder (63) is sleeved on the support frame (61); several magnetic blocks (62) are located between the conductor cylinder (63) and the support frame (61) and are connected to the support frame (61).

4. The eddy current buffer device according to claim 1, characterized in that, The rocker arm (2) and the main shaft (4) are connected through a force transmission component (8).

5. The eddy current buffer device according to claim 1, wherein The main shaft (4) and the base (3) are connected through a radial bearing (7).

6. An electric shovel, comprising a bucket body (200) and a bucket door (100), characterized in that, It further includes an eddy current buffer device as described in any one of claims 1 - 5, the base (3) is connected to the bucket body (200), and the end of the connecting rod (1) far from the rocker arm (2) is hinged to the bucket door (100).

7. The electric shovel according to claim 6, wherein The axis center of the main shaft is point A, the center of the hinge point of the connecting rod and the rocker arm is point B, the center of the hinge point of the connecting rod and the bucket door is point C, and the center of the hinge point of the bucket door and the bucket body is point D; the distance between point A and point B is a, the distance from point B to point C is b, the distance between point C and point D is c, and the distance between point A and point D is d; the line segment a, the line segment b, the line segment c and the line segment d form a planar four-bar mechanism.

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