Lifting device, electric shovel and control method

Abstract

The present application relates to the technical field of mine hoisting equipment, and provides a hoisting device, an electric shovel, and a control method. The hoisting device includes a base, a motor, two planetary reducers, a wire rope, two drums, and a braking system. The motor is fixed to the base. The motor includes a rotating shaft. The two planetary reducers are fixed to the base. The two planetary reducers are respectively arranged at both ends of the motor along the axial direction. The planetary reducer includes an input part and an output part that are connected to each other. The input parts of the two planetary reducers are respectively connected to the two ends of the rotating shaft along the axial direction. Part of the drum is sleeved on the outer circumference of the planetary reducer and connected to the output part. The two ends of the wire rope in the length direction are respectively wound on the drum, and the middle section of the wire rope is connected to the bucket of the electric shovel. The motor drives the drum to wind the wire rope to lift the bucket. The braking system is used to brake the motor and / or the planetary reducer. The hoisting device provided by the present application has high operating stability and high safety and reliability during emergency braking.

Description

Technical Field

[0001] The present application relates to the technical field of mine hoisting equipment, and in particular to a hoisting device, an electric shovel, and a control method. Background Art

[0002] Electric shovels, also known as large face shovels, are commonly used for mining. The hoist is the core drive mechanism in the shovel's excavation process, providing the power for digging and loading ore. This typically requires low-speed, high-torque output from the hoist.

[0003] In related technologies, lifting devices usually use asynchronous motors, which work in low-speed, heavy-load and under-load environments for a long time, have low efficiency and poor starting characteristics, resulting in insufficient operating reliability of the lifting device. Summary of the Invention

[0004] In view of this, embodiments of the present application hope to provide a lifting device, an electric shovel, and a control method to improve the performance and reliability of the lifting device.

[0005] To achieve the above-mentioned objectives, a first aspect of an embodiment of the present application provides a lifting device, comprising:

[0006] base;

[0007] a motor, fixed on the base, the motor comprising a rotating shaft;

[0008] Two planetary reducers are fixed on the base, and the two planetary reducers are respectively arranged at the two ends of the motor along the axial direction. The planetary reducers include an input part and an output part connected to each other, and the input parts of the two planetary reducers are respectively connected to the two ends of the rotating shaft along the axial direction;

[0009] A steel wire rope and two drums, wherein a portion of the drum is sleeved on the outer circumference of the planetary reducer and connected to the output portion, the steel wire rope is wound around the drums at both ends along its length, the middle section of the steel wire rope is used to connect to the bucket of the electric shovel, and the motor drives the drums to wind the steel wire rope to lift the bucket;

[0010] A braking system is used to brake the motor and / or the planetary reducer.

[0011] In some embodiments, the input part includes a sun gear, the output part includes a planetary gear and a planetary carrier rotatably connected to the planetary gear, the planetary carrier is fixedly connected to the drum, the number of the sun gear is one, the number of the planetary gear is at least one, and it is meshed with the sun gear.

[0012] In some embodiments, the braking system includes a brake, which is arranged on a side of each planetary reducer axially away from the motor. The brake is connected to an end of the input part away from the rotating shaft, and is used to output mechanical braking force to the planetary reducer.

[0013] In some embodiments, the lifting device includes a frequency converter, which is connected to the motor. The braking system includes an electronic control component and a control center, which are respectively connected to the electronic control component and the brake. The electronic control component is connected in series to the line connecting the motor and the frequency converter. When the power is off, the electronic control component disconnects the frequency converter from the motor and applies electromagnetic braking force to the motor.

[0014] In some embodiments, the electric control component includes a resistor, a first switch, and a second switch, wherein the resistor is connected to the control center, the first switch is provided on the electrical connection circuit between the motor and the inverter, and the second switch is provided on the electrical connection circuit between the motor and the resistor;

[0015] When powered on, the first switch switches on the electrical connection between the motor and the frequency converter, and the second switch switches off the electrical connection between the motor and the resistor;

[0016] In the power-off state, the first switch disconnects the electrical connection between the motor and the inverter, and the second switch connects the electrical connection between the motor and the resistor to short-circuit the three-phase stator windings of the motor.

[0017] In some embodiments, the braking system further includes a detection unit, which is at least arranged on the brake to collect braking data of the brake and transmit the braking data to the control center. The braking data at least includes any one or more of the braking speed and braking distance.

[0018] In some embodiments, each of the brakes includes a brake disc and at least two friction units, the friction unit is detachably docked with the brake disc, the friction unit is connected to the base, the brake disc is connected to one end of the input part away from the rotating shaft, and can rotate relative to the friction unit under the drive of the input part, the lifting device has a braking state and a non-braking state, in the non-braking state, the friction unit is separated from the brake disc, and in the braking state, at least two friction units are clamped at opposite ends of the brake disc along the axial direction to brake the planetary reducer by braking the brake disc.

[0019] In some embodiments, the motor includes an end cover and a cylinder, the end cover is arranged at opposite ends of the cylinder along the axial direction, the cylinder and the end cover define a chamber, the rotating shaft is arranged in the chamber, the end cover and the reel are axially spaced apart to define a spacing space, the end cover is provided with a vent, the vent passes through the end cover along the axial direction, and the spacing space is connected to the chamber through the vent to form a circulating air duct between the motor and the two reels.

[0020] In some embodiments, the motor includes a first fan blade assembly and a rotor assembly, the rotor assembly is connected to the rotating shaft, the first fan blade assembly includes at least one blade, the first fan blade assembly is located in the chamber, and is connected to the rotor assembly.

[0021] In some embodiments, the lifting device further includes a fan, which is connected outside the cylinder and communicates with the chamber.

[0022] In some embodiments, the lifting device further includes a second fan blade assembly, the second fan blade assembly includes at least one blade, and the second fan blade assembly is connected to a side of at least any one of the drums axially toward the end cover.

[0023] In some embodiments, a surface of the drum axially facing the end cover is recessed toward a side away from the end cover to form a mounting groove, and the second fan blade assembly is disposed in the mounting groove.

[0024] In some embodiments, a side surface of the end cover axially facing the drum is recessed toward a side away from the drum to form an escape space, and the escape space is used to escape the second fan blade assembly, and the escape space defines a portion of the interval space.

[0025] In some embodiments, the motor includes a stator assembly connected to the barrel, an air gap is provided between the stator assembly and the rotor assembly, and the air gap forms a part of the circulating air duct.

[0026] In some embodiments, the rotor assembly has a first channel running through the rotor assembly in a radial direction, and the first channel forms a part of the circulating air duct.

[0027] In some embodiments, the stator assembly has a second channel running through the stator assembly in a radial direction thereof, and the second channel is formed as a part of the circulation duct.

[0028] In some embodiments, the input portion is spline-connected to the rotating shaft.

[0029] In some embodiments, the lifting device includes an elastic buffer unit, and the input portion is connected to the rotating shaft through the elastic buffer unit.

[0030] A second aspect of an embodiment of the present application provides an electric shovel, which includes a pedestal, a boom, a lifting arm, a sheave, a bucket, and a lifting device as described in any one of the above items, wherein the lifting device is arranged on the pedestal, one end of the lifting arm is connected to the pedestal, the sheave is arranged at an end of the lifting arm away from the pedestal, one end of the bucket is connected to the wire rope through the sheave, and the other end is connected to the lifting arm through the boom.

[0031] A third aspect of the embodiments of the present application provides a control method for a lifting device, which is applied to any of the above lifting devices, including:

[0032] Determine whether the braking conditions are met;

[0033] If the conditions are met, disconnect the electrical connection between the inverter of the lifting device and the motor, and connect the electrical connection between the electronic control component of the braking system and the motor, so that the electronic control component applies electromagnetic braking force to the motor; and control the brake of the braking system to output mechanical braking force to the planetary reducer;

[0034] Wherein, the braking condition includes: the lifting device is in a power-off state.

[0035] In some embodiments, before braking the lifting device, the control method includes:

[0036] Controlling the lifting device to be in an energized state;

[0037] collecting operating parameters of the motor and the brake;

[0038] calculating, based on the operating parameters, a degree of degradation of the mechanical braking force of the brake and a maximum electromagnetic braking force of the electronic control assembly;

[0039] adjusting the electromagnetic braking force of the electronic control assembly based on the mechanical braking force of the brake;

[0040] The operating parameters of the brake include the lifting load of the lifting device, the braking speed and braking distance of the brake, and the operating parameters of the motor include the torque, current and voltage of the motor.

[0041] In some embodiments, adjusting the electromagnetic braking force of the electronic control component based on the mechanical braking force includes:

[0042] determining whether the maximum electromagnetic braking force of the electronic control component can supplement the mechanical braking force of the brake;

[0043] If so, adjusting the resistance value of the resistor of the electronic control component according to the required supplementary mechanical braking force value;

[0044] If not, the lifting device is controlled to stop and an alarm message is issued.

[0045] The lifting device provided in the embodiments of the present application achieves high drive efficiency by arranging a motor between two planetary reducers, and transmitting the motor's driving force to the planetary reducers at both ends via a rotating shaft. The planetary reducers at both ends reduce the speed of the reel, increasing the torque transmitted to the reel, and thus helping to improve the operating performance of the lifting device in the low-speed range. Furthermore, the motor, planetary reducer, and braking system are integrated together through the base, resulting in fewer transmission links, a compact overall structural layout, and a small axial dimension for the lifting device, making it easy to install in smaller spaces and facilitate upgrading and modification of the lifting device within smaller spaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic structural diagram of an electric shovel in one embodiment of the present application;

[0047] Figure 2 This is a structural diagram of a lifting device in one embodiment of the present application;

[0048] Figure 3 This is a partial cross-sectional schematic diagram of a lifting device in one embodiment of the present application, excluding the motor;

[0049] Figure 4 This is a partial cross-sectional schematic diagram of a lifting device in one embodiment of the present application;

[0050] Figure 5 This is a partial cross-sectional diagram of a motor and a reel in one embodiment of the present application;

[0051] Figure 6 This is an exploded schematic diagram of the elastic coupling, the input portion, and the rotating shaft in one embodiment of the present application;

[0052] Figure 7 This is a schematic structural diagram of a braking system in one embodiment of the present application;

[0053] Figure 8 This is a flow chart of a control method in one embodiment of the present application;

[0054] Figure 9 This is a flow chart of a control method in another embodiment of the present application.

[0055] Description of Reference Numerals

[0056] 10. Lifting device; 10a. Spacing space; 11. Base; 12. Motor; 12a. Chamber; 12b. Air gap; 121. Rotating shaft; 121a. Second coupling structure; 122. End cover; 122a. Ventilation port; 122b. Avoidance space; 123. Cylinder; 124. First fan blade assembly; 125. Rotor assembly; 125a. First channel; 1251. Rotor core; 1251a. Connecting section; 1251b. Transition section; 1251c. Mounting section; 126. Stator assembly; 126a. Second channel; 127. Rotor bearing; 128. Protective sleeve; 13. Planetary reducer; 131. Input section; 131a. First coupling structure; 1311. Sun gear; 1312. Buffer Components; 132. Output unit; 1321. Planetary gear; 1322. Planetary carrier; 133. Gear component; 14. Drum; 14a. Mounting slot; 14b. Second fan blade assembly; 15. Wire rope; 16. Braking system; 161. Brake; 1611. Brake disc; 1612. Friction unit; 1613. Brake sleeve; 1614. Brake end plate; 1615. End plate support sleeve; 162. Electronic control component; 1621. Resistor; 1622. First switching switch; 1623. Second switching switch; 163. Control center; 17. Frequency converter; 18. Fan; 19. Elastic buffer unit; 20. Pedestal; 30. Arm; 40. Lifting arm; 50. Head sheave; 60. Bucket; 100. Electric shovel. DETAILED DESCRIPTION

[0057] The following embodiments of the present invention are described in further detail with reference to the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0058] In the description of the embodiments of the present application, it should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present application. In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0059] In the description of the embodiments of this application, it should be noted that, unless otherwise specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art will understand the specific meanings of the above terms in the embodiments of this application based on the specific circumstances.

[0060] In the embodiments of the present application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0062] Electric shovels, also known as large face shovels, are commonly used for mining. The hoist is the core drive mechanism in the shovel's excavation process, providing the power for digging and loading ore. This typically requires low-speed, high-torque output from the hoist.

[0063] In the related art, lifting devices usually use asynchronous motors, which work in low-speed, heavy-load and under-load environments for a long time, have low efficiency and poor starting characteristics, resulting in insufficient operating reliability of the lifting device.

[0064] Based on the above situation, the first aspect of the embodiment of the present application provides a lifting device 10. Figures 1 to 7The lifting device 10 includes a base 11, a motor 12, two planetary reducers 13, a wire rope 15, two drums 14, and a braking system 16. The motor 12 is fixed to the base 11 and includes a rotating shaft 121. The two planetary reducers 13 are fixed to the base 11 and are respectively arranged at the two axial ends of the motor 12. The planetary reducers 13 include an input portion 131 and an output portion 132 that are connected to each other. The input portions 131 of the two planetary reducers 13 are respectively connected to the two axial ends of the rotating shaft 121. The drum 14 is partially sleeved on the outer circumference of the planetary reducer 13 and connected to the output portion 132. The wire rope 15 is wound around the drum 14 at both ends along the length direction. The middle section of the wire rope 15 is used to connect to the bucket 60 of the electric shovel 100. The motor 12 drives the drum 14 to wind the wire rope 15 to lift the bucket 60. The braking system 16 is used to brake the motor 12 and / or the planetary reducer 13 .

[0065] It should be noted that the motor 12 in this application is an inner rotor motor.

[0066] Exemplarily, the motor 12 of the present application is a three-phase synchronous motor, specifically a three-phase permanent magnet synchronous motor.

[0067] The embodiment of the present application is described by taking the motor 12 as a three-phase permanent magnet synchronous inner rotor motor as an example.

[0068] It should be noted that, unless otherwise clearly specified and limited, the axial and radial directions in this application refer to the axial and radial directions of the motor 12 , and the axial direction of the motor 12 is the same as the axial direction of the lifting device 10 , the drum 14 , and the planetary reducer 13 .

[0069] The motor 12 is fixed on the base 11, and the two planetary reducers 13 are fixed on the base 11. The base 11 can provide support for the motor 12 and the planetary reducer 13. The motor 12 and the planetary reducer 13 are fixed in axial position relative to the base 11, and the motor 12 and the two planetary reducers 13 are integrated together through the base 11, so that the structure of the lifting device 10 is more reliable and the layout is compact, which facilitates the transportation and assembly of the lifting device 10 as a whole.

[0070] The input parts 131 of the two planetary reducers 13 are respectively connected to the two ends of the rotating shaft 121 along the axial direction. That is, the two ends of the rotating shaft 121 along the axial direction are both load ends, and the motor 12 is a double-shaft motor 12.

[0071] The two planetary reducers 13 are respectively arranged at the two ends of the motor 12 along the axial direction. The two planetary reducers 13 are directly connected to the two ends of the rotating shaft 121 of the motor 12, which is conducive to saving space. At the same time, the driving force output by the motor 12 through the rotating shaft 121 can directly act on the planetary reducer 13, reducing transmission loss.

[0072] Part of the reel 14 is sleeved on the outer circumference of the planetary reducer 13 and connected to the output part 132. It should be noted that the reel 14 and the base 11 are spaced apart in the top-bottom direction, so that the movement of the reel 14 is smooth.

[0073] Exemplarily, the planetary reducer 13 includes a planetary carrier 1322 and a gear member 133 having an inner ring gear. When the planetary carrier 1322 is a frame, that is, the planetary carrier 1322 is fixed to the base 11, the gear member 133 is at least a portion of the output portion 132, the reel 14 is fixedly connected to the gear member 133 having an inner ring gear, and the planetary reducer 13 ultimately outputs through the gear member 133 having an inner ring gear. When the gear member 133 having an inner ring gear is a frame, that is, the gear member 133 is a frame fixed to the base 11, the planetary carrier 1322 is at least a portion of the output portion 132, the reel 14 is fixedly connected to the planetary carrier 1322, and the planetary reducer 13 ultimately outputs through the planetary carrier 1322. The planetary reducer 13 may also have other input and output modes, which are not limited here.

[0074] Part of the drum 14 is sleeved on the outer circumference of the planetary reducer 13, which can reduce the axial size of the lifting device 10, making the lifting device 10 compact as a whole and saving space.

[0075] The planetary reducer 13 receives the rotational driving force from the rotating shaft 121 through the input portion 131 and outputs the rotational driving force through the output portion 132, thereby driving the drum 14 to rotate relative to the base 11 through the output portion 132. Here, the motor 12 can reduce the rotation speed of the drum 14 and increase the torque transmitted from the rotating shaft 121 to the end of the drum 14 through the transmission of the planetary reducer 13, that is, semi-direct drive, thereby improving the operating performance of the lifting device 10 in the low-speed range and increasing the stability of the lifting device 10.

[0076] It should be noted that the wire rope 15 in the present application can be one or more, and each wire rope 15 is fixed at both ends along the length direction and wound on two drums 14. The middle section of each wire rope 15 is used to connect with the bucket 60 of the electric shovel 100. When the motor 12 drives the two drums 14 to rotate in the same direction at the same time to wind the wire rope 15, the length of the wire rope 15 outside the drum 14 is shortened, thereby pulling up the bucket 60.

[0077] When the drum 14 is reversed, the drum 14 is released from the winding of the wire rope 15, thereby lowering the bucket 60. The reversal of the drum 14 can be achieved by the gravity of the bucket 60 itself dragging the drum 14 in the opposite direction, thereby driving the motor 12 to reverse.

[0078] The braking system 16 is used to brake the motor 12 and / or the planetary reducer 13. For example, the braking system 16 may brake the motor 12 using electromagnetic braking, and the braking system 16 may brake the planetary reducer 13 using mechanical braking. The braking system 16 can brake both the motor 12 and the planetary reducer 13 simultaneously, or brake either the motor 12 or the planetary reducer 13 individually, as needed, without limitation.

[0079] It should be noted that the braking system 16 brakes the motor 12 and the planetary reducer 13 at the same time, that is, it performs electromagnetic braking on the motor 12 and mechanical braking on the planetary reducer 13. It is a compound braking mode that can provide a large braking force in a short time, and quickly stop the rotation of the rotating shaft 121, thereby quickly stopping the rotation of the drum 14, and increasing the safety and reliability of the lifting device 10 during emergency braking.

[0080] The lifting device 10 provided in the embodiment of the present application has high driving efficiency by arranging the motor 12 between the two planetary reducers 13, and the driving force of the motor 12 can be transmitted to the planetary reducers 13 at both ends through the rotating shaft 121. The planetary reducers 13 at both ends reduce the rotation speed of the reel 14, increase the torque transmitted to the reel 14, and help improve the operating performance of the lifting device 10 in the low-speed range. At the same time, the motor 12, planetary reducer 13, braking system 16, etc. are integrated together through the base 11, with fewer transmission links. The overall structural layout of the lifting device 10 is compact, and the axial size of the lifting device 10 is small, which is convenient for installation in a small space and convenient for upgrading and modifying the lifting device 10 in a small space.

[0081] The specific structures of the input unit 131 and the output unit 132 are not limited.

[0082] For some examples, see Figure 3 and Figure 6 The input portion 131 includes a sun gear 1311. The output portion 132 includes planetary gears 1321 and a planetary carrier 1322 rotatably connected to the planetary gears 1321. The planetary carrier 1322 is fixedly connected to the reel 14. There is one sun gear 1311. There is at least one planetary gear 1321, which meshes with the sun gear 1311.

[0083] The planet carrier 1322 is rotationally connected to the planet gears 1321, and the planet carrier 1322 is fixedly connected to the drum 14. This means that the planet gears 1321 and the planet carrier 1322 can rotate relative to each other, and the planet carrier 1322 is connected to the drum 14 to output torque and speed. In other words, in this embodiment, the gear member 133 having an inner ring gear serves as the frame and is fixed to the base 11. The planetary reducer 13 ultimately outputs power through the planet carrier 1322. Thus, one side of the planet gear 1321 meshes with the sun gear 1311, and the other side meshes with the inner ring gear on the gear member 133, so that the planet gear 1321 rotates around the sun gear 1311 while also rotating around its own central axis.

[0084] Here, through the rotational connection between the planetary gear 1321 and the planetary carrier 1322 , the rotational motion of the planetary gear 1321 around the sun gear 1311 can be converted into the rotational motion of the planetary carrier 1322 around the sun gear 1311 .

[0085] The number of the planetary gears 1321 is at least one. When the number of the planetary gears 1321 is two or more, the planetary gears 1321 may be evenly distributed circumferentially around the sun gear 1311 .

[0086] In the embodiment of the present application, the planetary reducer 13 has a single stage, that is, the number of sets of planetary gears 1321 and sun gear 1311 is one set. As a result, the planetary reducer 13 has fewer transmission links, making it easier to disassemble and maintain. At the same time, the single-stage planetary reducer 13 occupies less space in the axial direction, making the axial size of the lifting device 10 more compact.

[0087] Exemplarily, the planet carrier 1322 includes a planet shaft and a planet disk, one end of the planet shaft is interference-connected with the planet disk, and the other end is rotationally connected with the planet gear 1321 through a planet gear bearing, so that the planet gear 1321 and the planet carrier 1322 can rotate relative to each other.

[0088] The specific structure of the brake system 16 is not limited.

[0089] For some examples, see Figures 2 to 4 The braking system 16 includes a brake 161. The brake 161 is provided on a side of each planetary reducer 13 axially away from the motor 12. The brake 161 is connected to an end of the input portion 131 away from the rotating shaft 121 and is used to output a mechanical braking force to the planetary reducer 13.

[0090] The brake 161 is arranged on the side of each planetary reducer 13 axially away from the motor 12, that is, the brake 161 is arranged away from the motor 12, and the two brakes 161 are respectively arranged on both sides of the axial edge of the lifting device 10. In this way, the brake 161 has sufficient layout space and is not easy to interfere with the motor 12. Of course, it is also conducive to the maintenance of the brake 161.

[0091] The type of the brake 161 is not limited. Exemplarily, the brake 161 is a disc brake 161 .

[0092] The brake 161 is connected to the end of the input part 131 away from the rotating shaft 121, and is used to output a mechanical braking force to the planetary reducer 13. In this way, the direct braking object of the brake 161 is the input part 131 of the planetary reducer 13, which reduces the chance of the brake 161 directly braking the rotating shaft 121 of the motor 12 and causing the rotating shaft 121 to be easily worn, which helps to improve the working life and working safety of the motor 12.

[0093] For some examples, see Figure 1 and Figure 7 The lifting device 10 includes a frequency converter 17. The frequency converter 17 is connected to the motor 12. The braking system 16 includes an electronic control component 162 and a control center 163. The control center 163 is connected to the electronic control component 162 and the brake 161, respectively. The electronic control component 162 is connected in series to the line connecting the motor 12 and the frequency converter 17. When the power is off, the electronic control component 162 disconnects the frequency converter 17 from the motor 12 and applies electromagnetic braking force to the motor 12.

[0094] It should be noted that the inverter 17 is an electric power control device that applies variable frequency drive technology to control the speed and torque of the AC motor 12 by changing the operating voltage frequency and amplitude of the AC motor 12 .

[0095] Exemplarily, the frequency converter 17 is a four-quadrant frequency converter. The four-quadrant frequency converter can drive the motor 12 to operate in the first to fourth quadrants, for example, to drive the motor 12 to operate in the first, second, third, or fourth quadrants. When the drum 14 winds the wire rope 15 to lift the bucket 60, the speed and torque of the motor 12 are positive. At this time, the motor 12 operates in the first quadrant and is in a forward electric state. When the drum 14 releases the wire rope 15 to lower the bucket 60, the motor 12 operates in the second quadrant. At this time, the speed of the motor 12 is negative and the torque is positive. The motor 12 is in a reverse power generation state. At this time, energy is transferred from the motor 12 to the frequency converter 17, so that the energy fed back to the system by the motor 12 can be sent back to the power grid.

[0096] The frequency converter 17 is connected to the motor 12, which means that the input end of the frequency converter 17 is connected to the power grid, and the output end of the frequency converter 17 is connected to the motor 12, thereby changing the three-phase electricity of the power grid into the required frequency and amplitude to control the start, operation and stop of the motor 12.

[0097] For a three-phase permanent magnet synchronous motor, the inverter 17 is usually electrically connected to the three-phase stator winding of the motor 12 .

[0098] The electronic control component 162 is connected in series on the line connecting the motor 12 and the inverter 17, which means that the electronic control component 162 is arranged between the motor 12 and the inverter 17, which is conducive to the electronic control component 162 controlling the on and off of the working power supply of the motor 12 and applying electromagnetic braking force to the direct motor 12 in the case of power failure.

[0099] In this embodiment, the motor 12 is electromagnetically braked by the electronic control component 162 . The form of electromagnetic braking is not limited. For example, the electromagnetic braking may be energy-consuming braking.

[0100] It is understandable that when an electric shovel works for a long time in an environment with dust, frequent vibration and extreme temperature, the braking force of the brake will easily degrade after long-term use, resulting in the brake being unable to effectively brake the descent of the bucket in the event of a power outage, and the bucket is prone to falling accidents.

[0101] In this embodiment, the provision of the electronic control assembly 162 can, on the one hand, disconnect the motor 12 from the inverter 17 in the event of a power outage, thereby protecting the inverter 17 and increasing the structural reliability of the lifting device 10. Furthermore, the electronic control assembly 162 applies electromagnetic braking force to the motor 12, which can supplement the insufficient mechanical braking force during mechanical braking, achieving safe braking of the lifting device 10 in the event of a power outage, reducing the chance of the bucket 60 falling in the event of a power outage, and increasing the braking reliability of the lifting device 10. Furthermore, the electromagnetic braking method can complete start and stop operations in a short period of time, with a fast response speed and high safety. At the same time, it reduces physical contact with the motor 12, reduces mechanical wear, and helps extend the service life of the motor 12.

[0102] The specific structure of the electronic control component 162 is not limited.

[0103] For some examples, see Figure 7 The electric control component 162 includes a resistor 1621, a first switch 1622, and a second switch 1623. The resistor 1621 is connected to the control center 163. The first switch 1622 is set on the electrical connection circuit between the motor 12 and the inverter 17. The second switch 1623 is set on the electrical connection circuit between the motor 12 and the resistor 1621. When the power is on, the first switch 1622 conducts the electrical connection between the motor 12 and the inverter 17, and the second switch 1623 disconnects the electrical connection between the motor 12 and the resistor 1621. When the power is off, the first switch 1622 disconnects the electrical connection between the motor 12 and the inverter 17, and the second switch 1623 conducts the electrical connection between the motor 12 and the resistor 1621, so as to short-circuit the three-phase stator windings of the motor 12.

[0104] The control center 163 is used to detect and adjust the resistance value of the resistor 1621 .

[0105] The first switching switch 1622 is arranged on the electrical connection circuit of the motor 12 and the inverter 17, which means that the first switching switch 1622 is respectively connected to the three-phase stator winding of the motor 12 and the three-phase output end of the inverter 17 to simultaneously control the on and off between the three phases of the motor 12 and the inverter 17.

[0106] The second switch 1623 is provided on the electrical connection loop between the motor 12 and the resistor 1621 , which means that the second switch 1623 connects the resistor 1621 to the three-phase stator windings of the motor 12 respectively, so that the stator of the motor 12 is short-circuited between phases.

[0107] In a power outage, the bucket 60 of the electric shovel 100, due to its own gravity, pulls the motor 12's shaft 121 in the hoisting device 10 in the opposite direction. At this point, the first switch 1622 disconnects the motor 12 from the power source, while the second switch 1623 connects the motor 12's stator winding to the star-connected brake 161. The stator winding cuts the excitation magnetic flux, generating an induced electromotive force. The motor 12 is in a generating state and supplies power to the resistor 1621, generating a braking torque in the opposite direction of the shaft 121, or electromagnetic braking force, which quickly stops the hoisting device 10. During the power-off braking process, the system's kinetic energy is converted into electrical energy and consumed by the resistor 1621.

[0108] In this embodiment, when powered on, the inverter 17 is connected to the stator of the motor 12, the resistor 1621 is isolated from the motor 12 and the inverter 17, and the inverter 17 can control the normal start, operation and stop of the motor 12. In the event of a power outage, the inverter 17 is disconnected from the stator of the motor 12, thereby protecting the inverter 17. The resistor 1621 is short-circuited with the stator winding in star shape, and the stator winding and the resistor 1621 form a three-phase short-circuit circuit. On the one hand, the bucket 60 of the electric shovel 100 drags the motor 12 shaft 121 in the lifting device 10 in the opposite direction due to its own gravity. The motor 12 is in a power generation state, and the motor 12 outputs electrical energy to the three-phase short-circuit circuit formed by the stator winding and the resistor 1621, causing the motor 12 to generate a braking torque in the opposite direction to the rotation shaft 121, causing the lifting device 10 to stop quickly. On the other hand, the kinetic energy of the system is converted into electrical energy and consumed in the resistor 1621, so that the induced current generated by the stator winding of the motor 12 during braking is within the safe current range.

[0109] For some examples, see Figure 7 The braking system 16 further includes a detection unit. The detection unit is at least provided at the brake 161 to collect braking data of the brake 161 and transmit the braking data to the control center 163. The braking data includes at least one or more of the braking speed and the braking distance.

[0110] Exemplarily, the detection unit includes a rotary encoder.

[0111] Exemplarily, the detection unit may also be provided on the motor 12 to collect operating data of the motor 12 , for example, the voltage and current of the motor 12 .

[0112] Here, the braking system 16 collects the braking data of the brake 161 through the detection unit, and can calculate and evaluate the wear of the brake 161, so as to promptly prompt the user to maintain the brake 161, thereby improving the reliability and safety of the brake 161.

[0113] The specific structure of the brake 161 is not limited.

[0114] For some examples, see Figures 2 to 4 , each brake 161 includes a brake disc 1611 and at least two friction units 1612. The friction unit 1612 is detachably docked with the brake disc 1611. The friction unit 1612 is connected to the base 11. The brake disc 1611 is connected to one end of the input part 131 away from the rotating shaft 121, and can rotate relative to the friction unit 1612 under the drive of the input part 131. The lifting device 10 has a braking state and a non-braking state. In the non-braking state, the friction unit 1612 is separated from the brake disc 1611. In the braking state, at least two friction units 1612 are clamped at opposite ends of the brake disc 1611 along the axial direction to brake the planetary reducer 13 by braking the brake disc 1611.

[0115] Each brake 161 includes a brake disc 1611 and at least two friction units 1612 , that is, the brake 161 is a disc brake 161 . The friction units 1612 are connected to the base 11 to be fixed thereon.

[0116] The lifting device 10 has a braking state and a non-braking state, where the braking state refers to a mechanical braking state.

[0117] The friction unit 1612 may be a friction pad. Usually, two friction units 1612 form a group. In the present application, a brake 161 may have one or more groups of friction units 1612 .

[0118] The multiple or multiple groups described in the embodiments of the present application refer to a number of two or more.

[0119] Here, the planetary reducer 13 is braked by braking the brake disc 1611 , thereby indirectly braking the shaft 121 of the motor 12 , thereby improving the situation where direct braking of the shaft 121 easily causes impact and damage to the motor 12 .

[0120] In this embodiment, in the braking state, a set of friction units 1612 of brake 161, namely two friction units 1612, contact brake disc 1611 from opposite ends of the axial direction, thereby clamping brake disc 1611 and decelerating brake disc 1611 until it stops. In the non-braking state, friction units 1612 separate from brake disc 1611, allowing brake disc 1611 to rotate relative to friction units 1612 driven by input unit 131. In the non-braking state, friction units 1612 do not apply braking force to brake disc 1611. Thus, the working surface of brake 161 is flat and heat transfer occurs on both sides. Brake disc 1611 cools easily during rotation and is less likely to deform significantly. Braking performance of brake 161 is relatively stable. Furthermore, after prolonged use, the high-temperature expansion of brake disc 1611 enhances braking performance.

[0121] Exemplarily, the brake 161 further includes a brake sleeve 1613, a brake end plate 1614, and an end plate support sleeve 1615. The end of the input portion 131 away from the rotating shaft 121 meshes with the inner gear ring formed in the brake sleeve 1613 via drum-shaped teeth. The outer gear ring of the brake sleeve 1613 meshes with the inner gear ring of the brake end plate 1614. The brake end plate 1614 is fixedly connected to the brake disc 1611, so that rotation of the input portion 131 can synchronously drive rotation of the brake disc 1611. The end plate support sleeve 1615 has one axial end fixedly connected to the gear member 133, and the other end rotatably engages with the brake end plate 1614 via a bearing, thereby supporting the brake end plate 1614 and the end of the input portion 131 away from the rotating shaft 121, thereby improving the problem of deformation of the end of the input portion 131 away from the rotating shaft 121.

[0122] For some examples, see Figure 4 and Figure 5 The motor 12 includes an end cover 122 and a cylinder 123. The end cover 122 is arranged at opposite ends of the cylinder 123 in the axial direction. The cylinder 123 and the end cover 122 define a chamber 12a. The rotating shaft 121 is arranged in the chamber 12a. The end cover 122 and the reel 14 are spaced apart in the axial direction to define a spacing space 10a. The end cover 122 is provided with a vent 122a. The vent 122a penetrates the end cover 122 in the axial direction. The spacing space 10a is connected to the chamber 12a through the vent 122a to form a circulation air duct between the motor 12 and the two reels 14.

[0123] It should be noted that the number of the end covers 122 may also be two, which are respectively located on both sides of the cylinder 123 along the axial direction.

[0124] The end cover 122 and the reel 14 are spaced apart in the axial direction, which means that the end cover 122 and the reel 14 at the same end of the motor 12 are spaced apart in the axial direction, thereby forming a spacing space 10 a at each end of the motor 12 in the axial direction.

[0125] In this embodiment, the end cover 122 and the drum 14 are arranged at an axial interval. On the one hand, the probability of contact wear between the drum 14 and the end cover 122 can be reduced. On the other hand, the interval space 10a can connect the air in the external environment with the chamber 12a in the motor 12, forming a circulating air duct for air flow. The heat generated by the motor 12 can be quickly transferred to the external environment, thereby accelerating the heat dissipation rate of the motor 12, extending the service life of the motor 12 and reducing the impact of heat accumulation of the motor 12 on the planetary reducer 13 and the drum 14.

[0126] For some examples, see Figure 4 and Figure 5 The motor 12 includes a first fan blade assembly 124 and a rotor assembly 125. The rotor assembly 125 is connected to the rotating shaft 121. The first fan blade assembly 124 includes at least one blade. The first fan blade assembly 124 is located in the chamber 12a and is connected to the rotor assembly 125.

[0127] It should be noted that the rotor assembly 125 includes a rotor core 1251 , wherein the side of the rotor core 1251 close to the central axis is interference-connected with the rotating shaft 121 , and the side of the rotor core 1251 away from the central axis is used for mounting permanent magnets.

[0128] Thus, the rotor assembly 125 and the rotating shaft 121 together constitute the rotor of the motor 12 , ie, the rotating component in the motor 12 .

[0129] The first fan blade assembly 124 is located in the chamber 12a and is connected to the rotor assembly 125. That is to say, the first fan blade assembly 124 can rotate synchronously with the rotor assembly 125 in the chamber 12a, thereby enhancing the air flow speed in the chamber 12a, which is beneficial for discharging the air in the chamber 12a or sucking the air outside the chamber 12a into the chamber 12a, thereby improving the heat dissipation effect of the motor 12.

[0130] The first fan blade assembly 124 includes at least one blade. It can be understood that the first fan blade assembly 124 can be set on any side of the rotor core 1251 along the axial direction, and can also be set on both sides of the rotor core 1251 along the axial direction.

[0131] Here, the first fan blade assembly 124 is arranged on the rotor assembly 125, and can synchronously drive the first fan blade assembly 124 to rotate through the rotating shaft 121, thereby forming an airflow in the chamber 12a, discharging the air in the chamber 12a or sucking the air outside the chamber 12a into the chamber 12a. When the motor 12 is working, the inside of the motor 12 can automatically dissipate heat through the first fan blade assembly 124, thereby improving the reliability and safety of the operation of the motor 12.

[0132] For some examples, see Figure 2 、 Figure 4 and Figure 5 The lifting device 10 further includes a fan 18. The fan 18 is connected to the outside of the cylinder 123 and communicates with the chamber 12a.

[0133] The fan 18 is connected to the outside of the cylinder 123, and its position only needs to not interfere with other components and be convenient for inspection and maintenance.

[0134] Here, the fan 18 is used to form a negative pressure at the connection point with the chamber 12 a, thereby directly extracting the heat in the chamber 12 a. The fan 18 can accelerate the air flow rate, thereby improving the heat dissipation efficiency of the motor 12.

[0135] For some examples, see Figure 4 and Figure 5 The lifting device 10 further includes a second blade assembly 14b. The second blade assembly 14b includes at least one blade. The second blade assembly 14b is connected to a side of at least one of the reels 14 axially facing the end cover 122.

[0136] The second fan blade assembly 14b is connected to the side of at least one of the reels 14 axially facing the end cap 122. This means that the second fan blade assembly 14b can be provided on only one of the reels 14 or on both reels 14. In this way, during the rotation of the reel 14, the reel 14 can drive the second fan blade assembly 14b to rotate synchronously, thereby increasing the air flow speed in the compartment 10a and further improving the heat dissipation effect of the motor 12.

[0137] For example, the first fan blade assembly 124 includes two groups of blades, each group of blades has at least one blade, and the two groups of blades are respectively arranged on both sides of the rotor core 1251 along the axial direction, such as Figure 5 As shown in a and b, the second fan blade assembly 14b also includes two groups of blades, each group of blades has at least one blade, and the two groups of blades are respectively arranged on the side of the two reels 14 facing the motor 12, as shown in FIG. Figure 5 The blades of b and c are in the same direction, the blades of a and c are in opposite directions, and the blades of b and d are in opposite directions. Thus, when the shaft 121 and the reel 14 rotate, the air can pass through c, a, b, and d in sequence, so that the air can pass through Figure 5 The air enters the motor 12 from the left side, passes through the air gap 12b between the stator and the rotor, and is discharged from the right side. For the specific air flow direction, please refer to Figure 5 When the shaft 121 and the reel 14 rotate in opposite directions, Figure 5 The air flow direction in the reverse direction, the air can pass through d, b, a, c in sequence, the air from Figure 5It enters the motor 12 from the right side, passes through the air gap 12b between the stator and the rotor, and is discharged from the left side. It should be noted that since the way the drum 14 winds the wire rope 15 can be different, and the direction in which the lifting device 10 is set on the electric shovel 100 can also be different, Figure 5 The air flow direction indicated by the hollow arrow can be the air flow direction during the process of the motor 12 driving the drum 14 to wind the wire rope 15 and lifting the bucket 60, or it can be the air flow direction during the process of the motor 12 reversing and the drum 14 loosening the wire rope 15, so that the bucket 60 is lowered. There is no specific restriction.

[0138] For some examples, see Figure 4 and Figure 5 The surface of the drum 14 facing the end cover 122 in the axial direction is recessed toward the side away from the end cover 122 to form a mounting groove 14a. The second fan blade assembly 14b is disposed in the mounting groove 14a.

[0139] In this embodiment, the setting of the installation groove 14a can provide installation space for the second fan blade assembly 14b, expand the volume of the partition space 10a, so that the space within the partition space 10a is sufficient for the second fan blade assembly 14b to form a stable airflow, thereby improving heat dissipation stability.

[0140] For some examples, see Figure 4 and Figure 5 The end cover 122 is recessed in the axial direction toward the side of the reel 14 away from the reel 14 to form an escape space 122b. The escape space 122b is used to escape the second blade assembly 14b. The escape space 122b defines a portion of the separation space 10a.

[0141] The avoidance space 122b is used to avoid the second fan blade assembly 14b, and can also increase the volume of the separation space 10a, further improving the stability of the airflow formed by the rotation of the second fan blade assembly 14b.

[0142] Along the axial direction, the size of the partition space 10a at the recessed part is larger than that at the non-recessed part. For example, the vent 122a is arranged at the recessed part. In this way, the probability of dust or foreign matter directly entering the chamber 12a from the non-recessed part of the partition space 10a through the vent 122a can be reduced, thereby increasing the operating stability of the motor 12.

[0143] For some examples, see Figure 4 and Figure 5 The motor 12 includes a stator assembly 126. The stator assembly 126 is connected to the cylinder 123. An air gap 12b is formed between the stator assembly 126 and the rotor assembly 125. The air gap 12b forms a part of the circulation air duct.

[0144] It should be noted that the stator assembly 126 includes a stator core and a stator winding, wherein the outer ring of the stator core is fixedly connected to the cylinder 123, and the stator winding is wound on the stator core.

[0145] Generally, the air gap 12 b refers to the space between the stator assembly 126 and the rotor assembly 125 of the motor 12 .

[0146] There is an air gap 12b between the stator assembly 126 and the rotor assembly 125, so that the air entering from one end of the motor 12 can pass through the air gap 12b to reach the other end and be discharged from the other end. In this way, the air gap 12b is part of the circulating air duct, increasing the heat dissipation efficiency.

[0147] For some examples, see Figure 4 and Figure 5 The rotor assembly 125 has a first passage 125a extending radially therethrough. The first passage 125a is formed as a part of the circulating air duct.

[0148] It should be noted that, in this embodiment, the rotor assembly 125 includes a connecting section 1251a that is interference fit with the rotating shaft 121, a mounting section 1251c for mounting a permanent magnet, and a transition section 1251b for connecting the mounting section 1251c and the connecting section 1251a. The axial dimension of the transition section 1251b is smaller than the axial dimension of the mounting section 1251c. The axial sides of the transition section 1251b are respectively used to mount the first fan blade assembly 124. The portion of the mounting section 1251c that protrudes axially from the transition section 1251b is formed with a first channel 125a that penetrates radially. In this way, most of the air entering from the vent 122a on the end cover 122 can directly reach the air gap 12b through the first channel 125a. At the same time, the air in the air gap 12b can directly reach the first fan blade assembly 124 on the exhaust side through the first channel 125a, thereby improving the air circulation efficiency and thus improving the heat dissipation efficiency of the motor 12.

[0149] For some examples, see Figure 4 and Figure 5 The stator assembly 126 has a second passage 126a extending radially therethrough. The second passage 126a is formed as a part of the circulating air duct.

[0150] It should be noted that the second channel 126a and the first channel 125a are arranged correspondingly along the radial direction.

[0151] The gap between the stator assembly 126 and the cylinder 123 is connected to the air gap 12b through the second channel 126a, and the gap between the stator assembly 126 and the cylinder 123 is connected to the fan 18, which is beneficial for the fan 18 to take away the heat generated by the stator assembly 126. At the same time, it can also take away part of the heat generated by the rotor assembly 125 transmitted through the second channel 126a, which is beneficial to improving the overall heat dissipation efficiency of the motor 12.

[0152] For some examples, see Figures 3 to 5 The input portion 131 and the rotating shaft 121 are spline-connected.

[0153] Illustratively, an inner hole is formed at each end of the rotating shaft 121, and an inner hole is formed in the input portion 131 axially on the side closest to the motor 12. A buffer 1312 is provided in the inner hole. A portion of the buffer 1312 extends beyond the end of the input shaft and is configured to abut against the inner hole of the rotating shaft 121, thereby improving the axial load impact resistance between the planetary reducer 13 and the rotating shaft 121. The input portion 131 extends into the inner hole of the rotating shaft 121, and a spline fit is formed between the outer circumference of the input portion 131 and the inner hole of the rotating shaft 121, thereby enabling motion transmission between the rotating shaft 121 and the input shaft.

[0154] In this embodiment, the input portion 131 and the rotating shaft 121 are spline-connected, which simplifies the processing of the input portion 131 and the rotating shaft 121, facilitates assembly, and reduces processing and assembly costs.

[0155] For some examples, see Figure 6 The lifting device 10 includes an elastic buffer unit 19 . The input portion 131 is connected to the rotating shaft 121 through the elastic buffer unit 19 .

[0156] It should be noted that the elastic buffer unit 19 can be arranged between the input part 131 and the rotating shaft 121, and can also be arranged between the input part 131 and the brake disc 1611, so as to reduce the load impact between the brake disc 1611 and the input part 131 and improve the stability and reliability of the mechanical brake.

[0157] Exemplarily, the elastic buffer unit 19 is an elastic coupling. A first coupling structure 131a and a second coupling structure 121a are formed at the ends of the input portion 131 and the rotating shaft 121, respectively. The elastic coupling is disposed between the first coupling structure 131a and the second coupling structure 121a. The first coupling structure 131a engages with a portion of the elastic coupling, while the second coupling structure 121a engages with another portion of the elastic coupling. Together, the first coupling structure 131a, the elastic coupling, and the second coupling structure 121a form an elastic coupling, thereby reducing the impact of impact loads on the motor 12 during transmission and braking, thereby improving protection for the motor 12.

[0158] For some examples, see Figure 5 The motor 12 also includes a rotor bearing 127 and a protective cover 128 .

[0159] The inner ring of rotor bearing 127 forms an interference fit with shaft 121, while the outer ring of rotor bearing 127 forms an interference fit with end cap 122, thereby enabling shaft 121 to rotate relative to end cap 122 and cylinder 123. Protective sleeves 128 are sealed at both axial ends of rotor bearing 127 and connected to end cap 122. Protective sleeves 128 are used to seal rotor bearing 127, reducing the chance of dust intrusion into rotor bearing 127, thereby extending the service life of rotor bearing 127 and extending the maintenance cycle of motor 12.

[0160] The second aspect of the present application provides an electric shovel 100, see Figure 1 The electric shovel 100 includes a pedestal 20, a boom 30, a lifting arm 40, a sheave 50, a bucket 60, and a lifting device 10 provided in any embodiment of the present application. The lifting device 10 is arranged on the pedestal 20, one end of the lifting arm 40 is connected to the pedestal 20, the sheave 50 is arranged at the end of the lifting arm 40 away from the pedestal 20, one end of the bucket 60 is connected to the wire rope 15 through the sheave 50, and the other end is connected to the lifting arm 40 through the boom 30.

[0161] It should be noted that the base 20 of the electric shovel 100 is used to fix the lifting device 10 and one end of the boom 40 .

[0162] For example, a chassis is provided below the pedestal 20, which can be used to rotate and / or move the pedestal 20 located above. The chassis can include a slewing device and a running device. Specifically, the running device can be a crawler running device or a wheeled running device. The slewing device is used to rotate the entire pedestal 20, and the running device is used to move the entire pedestal 20.

[0163] In the embodiment of the present application, when the electric shovel 100 is excavating, the lifting device 10 is started, and the motor 12 drives the two drums 14 to synchronously wind the wire rope 15. The wire rope 15 is wound around the drum 14 through the sheave 50, that is, the pulley, at one end of the boom 40 away from the pedestal 20 to lift the bucket 60 for excavation. After the excavation is fully loaded, the braking system 16 brakes the motor 12. The braking system 16 overcomes the gravity of the bucket 60 and the gravity of the material in the bucket 60, so that the bucket 60 does not lower. After excavation, the pedestal 20 rotates until the bucket 60 is above the loading and unloading vehicle, and the material is unloaded. Thereafter, the pedestal 20 rotates again to the excavation point, and the braking system 16 releases the brake, and the bucket 60 is lowered by its own gravity. During the process of lowering the bucket 60, the drum 14 is dragged to reverse, thereby reversely dragging the motor 12, so that the motor 12 is in a power generation state and can feed the generated electricity back to the power grid. When the bucket 60 is lowered to the lowest point, the next excavation cycle is carried out.

[0164] It should be noted that when the three-phase permanent magnet synchronous motor is reversely dragged, no power grid is required for excitation, which eliminates the device required for excitation, saves equipment cost and space occupation, and is conducive to subsequent maintenance and upgrading on the base 20.

[0165] The electric shovel 100 provided in the embodiment of the present application achieves high drive efficiency by arranging the motor 12 of the lifting device 10 between two planetary reducers 13. The driving force of the motor 12 can be transmitted to the planetary reducers 13 at both ends via a rotating shaft 121. The planetary reducers 13 at both ends reduce the rotation speed of the drum 14, increasing the torque transmitted to the drum 14, thereby helping to improve the operating performance of the lifting device 10 in the low-speed range. Furthermore, the motor 12, planetary reducer 13, and brake system 16 are integrated together through the base 11, resulting in fewer transmission links and a compact overall structural layout of the lifting device 10. The lifting device 10 is also smaller in the axial direction, making it easier to install on a smaller pedestal 20 and easier to upgrade and modify the lifting device 10 within a smaller space, thereby improving the compactness of the electric shovel 100.

[0166] The third aspect of the present application provides a control method for a lifting device 10. Figures 8 and 9 , this control method is applied to the lifting device 10 provided in any embodiment of the present application.

[0167] Control methods include:

[0168] S100: Determine whether the braking condition is met.

[0169] S200: If the conditions are met, disconnect the electrical connection between the inverter of the lifting device and the motor, and connect the electrical connection between the electronic control component of the braking system and the motor. The electronic control component applies electromagnetic braking force to the motor; and controls the brake of the braking system to output mechanical braking force to the planetary reducer.

[0170] The braking condition includes: the lifting device 10 is in a power-off state.

[0171] It should be noted that the power-off state of the lifting device 10 refers to a state in which the power supply to the lifting device 10 is suddenly cut off during normal operation. At this time, the three-phase output of the inverter 17 is zero. The three-phase output of the inverter 17 is zero, including situations such as the inverter 17 failing to output three-phase power or the lack of three-phase power from the power grid.

[0172] That is, in step S100, when the lifting device 10 is in a power-off state, step S200 is executed, and mechanical braking force and electromagnetic braking force are applied to the motor 12 at the same time, so that the motor 12 can achieve emergency shutdown in the event of a power outage, thereby improving the safety of the work site.

[0173] In some embodiments, before braking the lifting device 10, the control method includes:

[0174] Control the lifting device to be in the energized state.

[0175] Collect the operating parameters of the motor and the brake.

[0176] Based on the operating parameters, the degree of degradation of the mechanical braking force of the brake is calculated, and the maximum electromagnetic braking force of the electronic control component is calculated.

[0177] Based on the mechanical braking force of the brake, the electromagnetic braking force of the electronic control component is adjusted.

[0178] The operating parameters of the brake 161 include the lifting load of the lifting device 10 , the braking speed and braking distance of the brake 161 , etc. The operating parameters of the motor 12 include the torque, current, voltage, etc. of the motor 12 .

[0179] Controlling the lifting device 10 to be in a powered-on state means that the lifting device 10 is in a working state, which may be a running state, a stationary state, or the like.

[0180] Collecting the operating parameters of the motor 12 and the brake 161 means that a detection unit is provided on the motor 12 and is in signal communication with the control center 163 , for detecting the operating parameters of the motor 12 and feeding back the operating parameters of the motor 12 to the control center 163 .

[0181] The operating parameters of the brake 161 are also detected by a detection unit provided on the brake 161 and in signal communication with the control center 163 and fed back to the control center 163 .

[0182] In addition, the detection unit can also be set at various parts of the lifting device 10 to detect various signals through the detection unit and feed them back to the control center 163.

[0183] Based on the operating parameters, the control center 163 calculates the degree of degradation of the mechanical braking force of the brake 161 and the maximum electromagnetic braking force of the electronic control assembly 162. Specifically, the degree of degradation of the mechanical braking force of the brake 161 can be the mechanical braking torque lost by the brake 161, while the maximum electromagnetic braking force of the electronic control assembly 162 can be the maximum electromagnetic braking torque that the resistor 1621 can provide at its minimum resistance.

[0184] The control center 163 calculates the degradation degree of the mechanical braking force of the brake 161 and the maximum electromagnetic braking force of the electronic control component 162, which can provide a basis for the subsequent steps of adjusting the electromagnetic braking force of the electronic control component.

[0185] Adjusting the electromagnetic braking force of the electronic control component 162 based on the mechanical braking force of the brake 161 means adjusting the electromagnetic braking force that the electronic control component 162 can achieve based on the degree of degradation of the current mechanical braking force of the brake 161 calculated as above. Specifically, the resistance value of the resistor 1621 can be adjusted so that the incremental electromagnetic braking force provided by the electronic control component 162 before and after the adjustment can make up for the mechanical braking force lost by the brake 161.

[0186] In this way, the electromagnetic braking force of the electronic control component 162 is used to supplement the insufficient braking torque caused by the wear of the brake 161. During the entire life cycle of the brake 161, the total braking force of the electronic control component 162 and the brake 161 on the rotating shaft 121 in the power-off state is within a certain threshold range and exceeds the emergency braking force required for safe braking of the lifting device 10 under emergency power-off conditions, thereby achieving safe braking of the lifting device 10 under emergency power-off conditions, improving the bucket drop accident of the electric shovel 100 under power-off conditions, and improving reliability and safety.

[0187] In some embodiments, adjusting the electromagnetic braking force of the electronically controlled assembly based on the mechanical braking force includes:

[0188] Determine whether the maximum electromagnetic braking force of the electronic control component can supplement the mechanical braking force of the brake.

[0189] If so, the resistance value of the resistor of the electronic control component is adjusted according to the required supplementary mechanical braking force value.

[0190] If not, the lifting device is controlled to stop and an alarm message is issued.

[0191] In the step of determining whether the maximum electromagnetic braking force of the electronic control component 162 can supplement the mechanical braking force of the brake 161, the maximum electromagnetic braking force refers to the electromagnetic braking force that can be provided when the resistance value of the resistor 1621 of the electronic control component 162 is minimum. At this time, the electromagnetic braking force that the resistor 1621 can provide is the maximum value.

[0192] It should be noted that the mechanical braking force of the brake 161 in its new state can fully meet and exceed the emergency braking force required by the lifting device 10 under emergency power-off conditions. During the operation of the lifting device 10, the mechanical braking force of the brake 161 gradually decreases due to wear. In this process, by successively adjusting the resistor 1621, specifically by successively reducing the resistance of the resistor 1621, the electromagnetic braking force provided by the resistor 1621 can be gradually increased, so that the sum of the current mechanical braking force of the brake 161 and the electromagnetic braking force that the electronic control component 162 can currently provide exceeds a certain range of the emergency braking force required under emergency power-off conditions, thereby improving the safety of the emergency braking lifting device 10 under emergency power-off conditions.

[0193] It is understandable that when the maximum electromagnetic braking force that can be provided when the resistance of resistor 1621 is minimum cannot compensate for the mechanical braking force lost by brake 161, there is no need to reduce the resistance, but directly force the shutdown to prompt the user to replace brake 161.

[0194] Here, whether the resistance of resistor 1621 should continue to be reduced is determined by whether the maximum electromagnetic braking force of the electronic control component 162 can supplement the mechanical braking force of the brake 161. That is, by comparing the maximum electromagnetic braking force corresponding to the minimum resistance of resistor 1621 obtained by previous calculation with the lost mechanical braking force, a pre-judgment is made before adjusting the resistance, which can improve the situation where the resistance of resistor 1621 is adjusted to the minimum, resulting in excessive short-circuit current and damage to the motor 12.

[0195] It should be noted that the resistor 1621 can be used to protect the stator winding of the motor 12, limit the short-circuit current, and improve the situation where the short-circuit current is too large and thus damages the motor 12.

[0196] In this way, the braking system 16 can monitor the degradation of the brake 161 in real time, quantify the braking capacity of the lifting device 10 and the replacement cycle of the brake 161, and once the mechanical braking force of the brake 161 is insufficient, the brake 161 is forced to be inspected to ensure the continuity and safety of the excavation work of the electric shovel 100.

[0197] For example, starting from the installation of the new brake 161 , data such as the current i and voltage v of the motor 12 , the speed v during braking, and the corresponding braking distance L are collected again.

[0198] The degree of weakening of the braking force of the brake 161 is calculated based on the data collected in real time.

[0199] The short-circuit characteristics of the motor 12 are calculated based on the motor 12 body parameters.

[0200] Under the condition that the permitted safety current threshold is not exceeded, the mechanical torque lost due to the degradation of the brake 161 can be supplemented by changing the resistance of the resistor 1621 connected in series.

[0201] When the control center 163 calculates that the required supplementary braking torque is close to the safety threshold, that is, the required supplementary braking force of the lifting device 10 is close to the maximum electromagnetic braking force that the resistor 1621 can provide, an alarm is issued to shut down the machine.

[0202] The short-circuit characteristic calculation process of the motor 12 is as follows:

[0203] In the case of power failure, the three phases of the motor 12 are short-circuited, and a resistor 1621 is connected in series for dynamic braking. At this time, the three-phase circuit of the motor 12 satisfies the following equation:

[0204] (1-1);

[0205] (1-2);

[0206] in is the phase resistance, is the d-axis current, is the q-axis current, is the d-axis inductance component, is the q-axis inductance component, is the electrical angular velocity of the rotor of the motor 12, is the resistance value of each phase of resistor 1621, is the magnetic flux of the permanent magnet, t is the time, is the time derivative of the d-axis current, is the time derivative of the q-axis current.

[0207] (1-3), where is the mechanical angular velocity of the rotor of the motor 12, and p is the number of pole pairs of the motor 12.

[0208] The corresponding electromagnetic torque characteristics are: (1-4), where is the electromagnetic torque.

[0209] According to the above formulas (1-1), (1-2), (1-3), and (1-4), the electrical angular velocity of the motor 12 is and the resistance of each phase of resistor 1621 As the independent variable, the corresponding electromagnetic torque under short-circuit energy consumption braking can be obtained. Characteristics of and characteristics of current I.

[0210] For example, see Figure 9 , the control method of the lifting device 10 is as follows:

[0211] S301: The lifting device is running.

[0212] S302: Determine whether the braking condition is met.

[0213] S303: If yes, disconnect the electrical connection between the inverter of the lifting device and the motor, and connect the electrical connection between the electronic control component of the braking system and the motor, so that the electronic control component applies electromagnetic braking force to the motor; and control the brake of the braking system to output mechanical braking force to the planetary reducer.

[0214] S304: If not, maintain the electrical connection between the inverter and the motor of the lifting device to control the lifting device to be in a powered state.

[0215] S305: Collect operating parameters of the motor and the brake.

[0216] S306: Calculate the degradation degree of the mechanical braking force of the brake based on the operating parameters, and calculate the maximum electromagnetic braking force of the electronic control component.

[0217] S307: Determine whether the maximum electromagnetic braking force of the electronic control component can supplement the mechanical braking force of the brake.

[0218] S308: If yes, adjust the resistance value of the resistor of the electronic control component according to the required supplementary mechanical braking force value.

[0219] S309: If not, the lifting device is controlled to stop and an alarm message is issued.

[0220] It should be noted that when the lifting device 10 is controlled to stop and an alarm message is issued, the brake system 16 forcibly locks the brake 161. The brake 161 needs to be replaced before the lifting device 10 can be restarted.

[0221] At the same time, after the resistance value of the resistor 1621 of the electric control component 162 is adjusted, the lifting device 10 continues to operate, thereby ensuring the continuity of the operation of the lifting device 10.

[0222] Through the control method of the present application, on the one hand, the braking system 16 can simultaneously perform electromagnetic braking and mechanical braking on the lifting device 10, thereby realizing safe composite braking of the lifting device 10 under emergency power-off conditions. The bucket 60 driven by the lifting device 10 can be safely braked, reducing the probability of bucket drop accidents of the electric shovel 100 under power-off conditions. On the other hand, the braking system 16 can monitor the degradation of the brake 161 in real time, quantify the braking capacity of the lifting device 10 and the replacement cycle of the brake 161. Once the mechanical braking force of the brake 161 is insufficient, the brake 161 is forcibly inspected to ensure the continuity and safety of the excavation work of the electric shovel 100.

[0223] The various embodiments / implementations provided in this application can be combined with each other without causing any contradiction.

[0224] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A lifting device, applied to an electric shovel, characterized in that: include: base; a motor, fixed on the base, the motor comprising a rotating shaft; Two planetary reducers are fixed on the base, and the two planetary reducers are respectively arranged at the two ends of the motor along the axial direction. The planetary reducers include an input part and an output part connected to each other, and the input parts of the two planetary reducers are respectively connected to the two ends of the rotating shaft along the axial direction; A steel wire rope and two drums, wherein a portion of the drum is sleeved on the outer circumference of the planetary reducer and connected to the output portion, the steel wire rope is wound around the drums at both ends along its length, the middle section of the steel wire rope is used to connect to the bucket of the electric shovel, and the motor drives the drums to wind the steel wire rope to lift the bucket; a braking system for simultaneously performing electromagnetic braking on the motor and mechanical braking on the planetary reducer; The braking system includes a brake, which is arranged on a side of each planetary reducer axially away from the motor, and is connected to an end of the input portion away from the rotating shaft, for outputting a mechanical braking force to the planetary reducer; The lifting device includes a frequency converter, which is connected to the motor. The braking system includes an electronic control component and a control center, which are respectively connected to the electronic control component and the brake. The electronic control component is connected in series to the line connecting the motor and the frequency converter. When the power is off, the electronic control component disconnects the frequency converter from the motor and applies electromagnetic braking force to the motor. The electromagnetic braking force of the electronic control component can be adjusted based on the mechanical braking force of the brake.

2. The lifting device according to claim 1, characterized in that The input part includes a sun gear, the output part includes a planetary gear and a planetary carrier rotatably connected to the planetary gear, the planetary carrier is fixedly connected to the drum, the number of the sun gear is one, the number of the planetary gear is at least one, and it is meshed with the sun gear.

3. The lifting device according to claim 1, characterized in that The electric control component includes a resistor, a first switch, and a second switch. The resistor is connected to the control center. The first switch is provided on the electrical connection circuit between the motor and the inverter. The second switch is provided on the electrical connection circuit between the motor and the resistor. When powered on, the first switch switches on the electrical connection between the motor and the frequency converter, and the second switch switches off the electrical connection between the motor and the resistor; In the power-off state, the first switch disconnects the electrical connection between the motor and the inverter, and the second switch connects the electrical connection between the motor and the resistor to short-circuit the three-phase stator windings of the motor.

4. The lifting device according to claim 1, characterized in that The braking system further includes a detection unit, which is at least provided at the brake to collect braking data of the brake and transmit the braking data to the control center. The braking data includes at least one or more of braking speed and braking distance.

5. The lifting device according to claim 1, characterized in that Each of the brakes includes a brake disc and at least two friction units, the friction unit is detachably docked with the brake disc, the friction unit is connected to the base, the brake disc is connected to one end of the input part away from the rotating shaft, and can rotate relative to the friction unit under the drive of the input part, the lifting device has a braking state and a non-braking state, in the non-braking state, the friction unit is separated from the brake disc, and in the braking state, at least two friction units are clamped at opposite ends of the brake disc along the axial direction to brake the planetary reducer by braking the brake disc.

6. The lifting device according to claim 1, characterized in that The motor includes an end cover and a cylinder, the end cover is arranged at opposite ends of the cylinder along the axial direction, the cylinder and the end cover define a chamber, the rotating shaft is arranged in the chamber, the end cover and the reel are axially spaced apart to define a spacing space, the end cover is provided with a vent, the vent passes through the end cover along the axial direction, the spacing space is connected with the chamber through the vent to form a circulating air duct between the motor and the two reels.

7. The lifting device according to claim 6, characterized in that The motor includes a first fan blade assembly and a rotor assembly, the rotor assembly is connected to the rotating shaft, the first fan blade assembly includes at least one blade, the first fan blade assembly is located in the chamber and is connected to the rotor assembly; And / or, the lifting device further includes a fan, which is connected outside the cylinder and communicates with the chamber.

8. The lifting device according to claim 6, characterized in that The lifting device further includes a second fan blade assembly, the second fan blade assembly includes at least one blade, and the second fan blade assembly is connected to a side of at least any one of the drums axially facing the end cover.

9. The lifting device according to claim 8, characterized in that The surface of the drum facing the end cover in the axial direction is recessed toward a side away from the end cover to form a mounting groove, and the second fan blade assembly is disposed in the mounting groove; And / or, the end cover is recessed along the axial direction on one side surface of the drum away from the drum to form an escape space, the escape space is used to escape the second fan blade assembly, and the escape space defines a part of the interval space.

10. The lifting device according to claim 7, characterized in that The motor includes a stator assembly, the stator assembly is connected to the cylinder, an air gap is formed between the stator assembly and the rotor assembly, and the air gap forms a part of the circulation duct; And / or, the rotor assembly has a first channel running through it in a radial direction, and the first channel forms a part of the circulating air duct; And / or, the stator assembly has a second channel running through the stator assembly in a radial direction, and the second channel forms a part of the circulating air duct.

11. The lifting device according to claim 1, characterized in that The input part is spline-connected to the rotating shaft; and / or the lifting device includes an elastic buffer unit, and the input part is connected to the rotating shaft via the elastic buffer unit.

12. An electric shovel, characterized in that: The electric shovel includes a pedestal, a boom, a lifting arm, a sheave, a bucket, and a lifting device according to any one of claims 1 to 11, wherein the lifting device is arranged on the pedestal, one end of the lifting arm is connected to the pedestal, the sheave is arranged at the end of the lifting arm away from the pedestal, one end of the bucket is connected to the wire rope through the sheave, and the other end is connected to the lifting arm through the boom.

13. A method for controlling a lifting device, applied to the lifting device according to any one of claims 1 to 11, characterized in that: include: Determine whether the braking conditions are met; If the conditions are met, disconnect the electrical connection between the inverter of the lifting device and the motor, and connect the electrical connection between the electronic control component of the braking system and the motor, so that the electronic control component applies electromagnetic braking force to the motor; and control the brake of the braking system to output mechanical braking force to the planetary reducer; Wherein, the braking condition includes: the lifting device is in a power-off state.

14. The control method according to claim 13, characterized in that: Before braking the lifting device, the control method includes: Controlling the lifting device to be in an energized state; collecting operating parameters of the motor and the brake; calculating, based on the operating parameters, a degree of degradation of the mechanical braking force of the brake and a maximum electromagnetic braking force of the electronic control assembly; adjusting the electromagnetic braking force of the electronic control assembly based on the mechanical braking force of the brake; The operating parameters of the brake include the lifting load of the lifting device, the braking speed and braking distance of the brake, and the operating parameters of the motor include the torque, current and voltage of the motor.

15. The control method according to claim 14, characterized in that: Adjusting the electromagnetic braking force of the electronic control component based on the mechanical braking force includes: determining whether the maximum electromagnetic braking force of the electronic control component can supplement the mechanical braking force of the brake; If so, adjusting the resistance value of the resistor of the electronic control component according to the required supplementary mechanical braking force value; If not, the lifting device is controlled to stop and an alarm message is issued.

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