Self-lubricating planetary reducer and self-lubricating method

Abstract

The invention discloses a self-lubricating planetary reducer and a self-lubricating method, and the self-lubricating planetary reducer comprises an oil storage tank which is arranged in the planetary reducer and contains lubricating oil; the outlet is formed in the bottom of the oil storage tank and communicates inside and outside the oil storage tank; the blocking groove is formed in the bottom of the oil storage tank and is communicated and coupled with the outlet; the accommodating groove is formed in the bottom of the oil storage tank and is communicated and coupled with the blocking groove; the magnetic fluid is a colloidal solution formed by dispersing nanoscale magnetic particles in a base solution. The aggregation or dispersion state of the magnetic fluid at the outlet of the oil storage tank is controlled through the on-off and intensity change of the external magnetic field by utilizing the fluidity and controllability of the magnetic fluid under the action of the magnetic field, so that the opening or closing of the outlet is realized, and the outflow of lubricating oil is controlled; the lubricating oil intermittently flows out to avoid accumulation of the lubricating oil in the planetary reducer, and different from a traditional lubricating mode, the planetary reducer can operate for a long time at the high temperature, and power loss caused by oil bath lubrication can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of planetary reducer transmission devices, and in particular to a self-lubricating planetary reducer and a self-lubricating method. Background Art

[0002] Planetary reducer is a widely used industrial product that can reduce the speed of the motor and increase the output torque. Its main structures are bearings, planetary gears, sun gears, and internal gear rings.

[0003] In order to reduce the wear of the planetary reducer during operation, the planetary reducer will be lubricated. The existing conventional lubrication methods for planetary reducers are: Grease lubrication is often used in low-speed, light-load or small planetary reducers (such as micro servo reducers). Lithium-based grease (NLGI grade 2) is filled once during assembly, and the grease is diffused to the gear meshing surface through the rotation of the planet carrier. Sealed bearings (such as double-lip contact seals) are used to prevent grease leakage. The disadvantage is that the heat dissipation capacity is poor, and carbonization will occur due to temperature increase, which increases the wear of the planetary reducer during operation. Oil bath lubrication is often used in general-purpose planetary reducers with medium and low speeds and medium loads. ISOVG220-320 mineral oil is injected into the housing, and the liquid level submerges 1 / 3-1 / 2 of the diameter of the planetary gear. When the planetary gear rotates, it stirs the oil to form splash lubrication covering the sun gear, planetary bearings and other parts. The disadvantage is that there is power loss when stirring the oil at high speed, and the power loss can reach 3%-5%. Summary of the invention

[0004] The purpose of the present invention is to provide a self-lubricating planetary reducer and a self-lubricating method, which are different from the existing conventional lubrication methods, can enable the planetary reducer to maintain operation for a long time at a temperature exceeding 80°C, and overcome the problem of power loss in oil bath lubrication.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A self-lubricating planetary reducer, comprising: The oil storage tank is arranged inside the planetary reducer and contains lubricating oil; An outlet is provided at the bottom of the oil storage tank, connecting the inside and outside of the oil storage tank; The blocking groove is provided at the bottom of the oil storage tank and is connected and coupled with the outlet; The containing groove is arranged at the bottom of the oil storage tank and is connected and coupled with the blocking groove; Magnetic fluid, a colloidal solution formed by nano-scale magnetic particles dispersed in a base fluid; Wherein, a first magnetic field and a second magnetic field are respectively arranged at both ends of the virtual line connecting the blocking groove and the accommodating groove. When only the first magnetic field exists near the magnetorheological fluid, the magnetorheological fluid flows into the blocking groove. When only the second magnetic field exists near the magnetorheological fluid, the magnetorheological fluid flows into the accommodating groove. The magnetic field intensity of the first magnetic field has two states, which are respectively: The first magnetic field intensity ensures the complete flow of the magnetorheological fluid; The second magnetic field intensity causes the magnetorheological fluid to generate sufficient yield stress to seal the outlet.

[0006] Preferably, the planetary speed reducer further includes a housing. An internal gear ring is arranged inside the housing. The housing is rotatably connected with a planetary carrier and a coupling. The planetary carrier is rotatably connected with three planetary gears through bearings. The three planetary gears are all meshed and connected with the internal gear ring. The coupling is coaxially and fixedly connected with a sun gear. The sun gear is located between the three planetary gears and is meshed and connected with the three planetary gears.

[0007] Preferably, an inclined plate is detachably arranged inside the housing by bolts. A magnetic layer is arranged on the side of the inclined plate facing away from the outlet. One end of the inclined plate close to the planetary gear is flush with the planetary gear.

[0008] Preferably, receiving cylinders are arranged at two symmetrical positions of the housing. An iron core is fixedly connected inside the receiving cylinder. An induction coil is wound around the iron core. A control system is also arranged on the housing. Both ends of the two induction coils are connected to the control system. The on / off and magnetic field intensity of the two induction coils are controlled through the control system.

[0009] Preferably, the control system includes: A power supply module for providing power; A control module for receiving signals and sending control instructions; A switching module for controlling the on / off of its circuit through the instruction of the control module and switching the connection state of the circuit; And a resistance adjustment module for adjusting the resistance value in the circuit forming the first magnetic field.

[0010] Preferably, the switching module is set with a timing switching mode through a timer. When the set switching time interval is reached, the control module issues a switching instruction, and the first magnetic field and the second magnetic field are alternately formed by the intermittent on / off of two relays respectively connected to the two induction coils, one opening and the other closing.

[0011] Preferably, the resistance adjustment module adopts a digital potentiometer RP. After the first magnetic field is formed to reach the first magnetic field intensity, an adjustment instruction issued by the control module causes the resistance value in the circuit of the first magnetic field to decrease, so that the first magnetic field transitions from the first magnetic field intensity to the second magnetic field intensity.

[0012] A self-lubricating method for a planetary speed reducer, which is applied to the planetary speed reducer, includes the following steps: At the set switching time interval, the control module issues a switching instruction. The switching module receives the switching instruction for the first time, energizes the induction coil that forms the first magnetic field, and de-energizes the induction coil that forms the second magnetic field. At this moment, the first magnetic field is at the first magnetic field intensity (magnetic field intensity ≤ 10 mT) to ensure that the ferrofluid flows completely; After the first magnetic field intensity is maintained for 50 - 80 milliseconds and the ferrofluid completely flows into the blocking groove, the control module issues an adjustment instruction. The resistance adjustment module receives the adjustment instruction to decrease the resistance value in the circuit of the first magnetic field, and the first magnetic field transitions from the first magnetic field intensity to the second magnetic field intensity (magnetic field intensity ≥ 50 mT), causing the ferrofluid to generate sufficient yield stress to seal the outlet, and the lubricating oil stays inside the storage tank; The switching module receives the switching instruction for the second time, de-energizes the induction coil that forms the first magnetic field, and energizes the induction coil that forms the second magnetic field. At this moment, the magnetic field intensity of the second magnetic field ≤ 10 mT to ensure that the ferrofluid flows completely, and the ferrofluid completely flows into the receiving groove; And so on in a cycle.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, by arranging a ferrofluid that can be opened and closed at the outlet of the storage tank for storing lubricating oil, and utilizing the fluidity and controllable characteristics of the ferrofluid under the action of a magnetic field, through the on / off and intensity change of the external magnetic field, the aggregation or dispersion state of the ferrofluid at the outlet of the storage tank is controlled, thereby realizing the opening or closing of the outlet, and further controlling the outflow of the lubricating oil. The intermittent outflow of the lubricating oil avoids the accumulation of lubricating oil inside the planetary reducer. Different from the traditional lubrication method, it can not only ensure the long-term operation of the planetary reducer at high temperature, but also reduce the power loss caused by oil bath lubrication. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 FIG. is a schematic structural diagram of a self-lubricating planetary reducer proposed by the present invention; Figure 2 FIG. is a schematic internal structure diagram of a self-lubricating planetary reducer proposed by the present invention; Figure 3 FIG. is a schematic sectional structure diagram of a storage tank and an inclined plate in a self-lubricating planetary reducer proposed by the present invention; Figure 4 FIG. is a schematic circuit structure diagram between two induction coils and a power supply in a self-lubricating planetary reducer proposed by the present invention.

[0015] In the figure: 1, storage tank; 2, outlet; 3, blocking groove; 4, receiving groove; 5, housing; 6, internal gear ring; 7, planetary carrier; 8, coupling; 9, planetary gear; 10, sun gear; 11, inclined plate; 12, magnetic layer; 13, receiving cylinder; 14, iron core; 15, heat insulation box. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0017] A self-lubricating planetary speed reducer, comprising: An oil storage tank 1, arranged inside the planetary speed reducer and containing lubricating oil; An outlet 2, opened at the bottom of the oil storage tank 1 and communicating the inside and outside of the oil storage tank 1; A blocking groove 3, opened at the bottom of the oil storage tank 1 and connected and coupled with the outlet 2; A receiving groove 4, opened at the bottom of the oil storage tank 1 and connected and coupled with the blocking groove; Magnetorheological fluid, a colloidal solution formed by dispersing nanoscale magnetic particles in a base liquid; Wherein, a first magnetic field and a second magnetic field are respectively arranged in the two end directions of the virtual connection line between the blocking groove 3 and the receiving groove 4. When only the first magnetic field exists near the magnetorheological fluid, the magnetorheological fluid flows into the blocking groove 3. When only the second magnetic field exists near the magnetorheological fluid, the magnetorheological fluid flows into the receiving groove 4. The magnetic field intensity of the first magnetic field has two states, namely: The first magnetic field intensity, ensuring the complete flow of the magnetorheological fluid; The second magnetic field intensity, enabling the magnetorheological fluid to generate sufficient yield stress to seal the outlet 2.

[0018] Through the above technical solution, a magnetorheological fluid capable of opening and closing is arranged at the outlet 2 of the oil storage tank 1 for storing lubricating oil. By utilizing the fluidity and controllable characteristics of the magnetorheological fluid under the action of a magnetic field, the aggregation or dispersion state of the magnetorheological fluid at the outlet 2 of the oil storage tank 1 is controlled through the on-off and intensity change of an external magnetic field, thereby realizing the opening or closing of the outlet 2, and further controlling the outflow of the lubricating oil. The intermittent outflow of the lubricating oil avoids the accumulation of the lubricating oil inside the planetary speed reducer. Different from the traditional lubrication method, it can not only ensure the long-term operation of the planetary speed reducer at high temperature, but also reduce the power loss caused by oil bath lubrication.

[0019] The planetary speed reducer further includes a housing 5. An internal gear ring 6 is arranged inside the housing 5. The housing 5 is rotatably connected with a planetary carrier 7 and a coupling 8. The planetary carrier 7 is rotatably connected with three planetary gears 9 through bearings. All three planetary gears 9 are meshed with the internal gear ring 6. The coupling 8 is coaxially and fixedly connected with a sun gear 10. The sun gear 10 is located between the three planetary gears 9 and meshed with the three planetary gears 9.

[0020] Inside the housing 5, an inclined plate 11 is detachably provided by bolts. On the side of the inclined plate 11 facing away from the outlet 2, a magnetic layer 12 is provided. One end of the inclined plate 11 close to the planet gear 9 is flush with the planet gear 9.

[0021] Through the above technical solution, the lubricating oil flowing out from the outlet 2 drops on the inclined plate 11. In order to avoid the pollution of the lubricating oil by the magnetic fluid, the magnetic layer 12 is used to continuously adsorb the lubricating oil falling on the inclined plate 11, tightly adsorb the magnetic fluid mixed in the lubricating oil on the inclined plate 11, and the lubricating oil slides down under the action of gravity and finally falls on the rotating planet gear 9. The splash lubrication formed by the rotating force of the planet gear 9 covers the sun gear 10, the planet gear 9, the bearing and the planet carrier 7.

[0022] Receiving cylinders 13 are provided at two symmetric positions of the housing 5. A iron core 14 is fixedly connected inside the receiving cylinder 13. An induction coil is wound around the iron core 14. A control system is also provided on the housing 5. Both ends of the two induction coils are connected to the control system, and the on / off and magnetic field intensity of the two induction coils are controlled by the control system.

[0023] Through the above technical solution, when the two induction coils are energized, they respectively correspond to the first magnetic field and the second magnetic field.

[0024] The control system includes: A power supply module for providing power; A control module for receiving signals and sending control instructions; A switching module that controls the on / off of its circuit through the instructions of the control module and switches the connection state of the circuit; And a resistance adjustment module for adjusting the resistance value in the circuit forming the first magnetic field.

[0025] The switching module is set with a timing switching mode through a timer. When the set switching time interval is reached, the control module issues a switching instruction, and the first magnetic field and the second magnetic field are alternately formed by the intermittent on / off of the two relays respectively connected to the two induction coils, one opening and one closing.

[0026] The resistance adjustment module uses a digital potentiometer RP. After the first magnetic field reaches the first magnetic field intensity, the adjustment instruction issued by the control module causes the resistance value in the circuit of the first magnetic field to decrease, and then the first magnetic field transitions from the first magnetic field intensity to the second magnetic field intensity.

[0027] Working principle: When the planetary reducer starts to work, the control system starts synchronously. With a set switching time interval (such as 2 - 3 minutes), the control module issues a switching instruction. The switching module receives the switching instruction for the first time, energizes the induction coil forming the first magnetic field, and de-energizes the induction coil forming the second magnetic field. At this moment, the first magnetic field has a first magnetic field intensity (magnetic field intensity ≤ 10 mT) to ensure that the magnetorheological fluid flows completely. After maintaining the first magnetic field intensity for 50 - 80 milliseconds (the magnetorheological fluid completely flows into the blocking groove 3), the control module issues an adjustment instruction. The resistance adjustment module receives the adjustment instruction, reduces the resistance value in the circuit of the first magnetic field, and the first magnetic field transitions from the first magnetic field intensity to the second magnetic field intensity (magnetic field intensity ≥ 50 mT), causing the magnetorheological fluid to generate sufficient yield stress to seal the outlet 2, and the lubricating oil stays inside the oil storage tank 1; The switching module receives the switching instruction for the second time, de-energizes the induction coil forming the first magnetic field, and energizes the induction coil forming the second magnetic field. At this moment, the magnetic field intensity of the second magnetic field ≤ 10 mT to ensure that the magnetorheological fluid flows completely, and the magnetorheological fluid completely flows into the receiving groove 4; This process repeats cyclically.

[0028] It should be noted that: In this solution, the magnetorheological fluid selects a mineral oil-based MF matching gear oil that is the same as the lubricating oil base fluid, with a particle size ≤ 10 nm to avoid clogging the outlet 2 (the aperture of the outlet 2 ≥ 0.5 mm). The small size effect of the nanoscale particles can significantly reduce the van der Waals force between the particles and inhibit aggregation and sedimentation at high temperatures; the thermal stability of the mineral oil base is better than that of ordinary greases and can withstand the high temperatures generated by the long-term operation of the planetary reducer (under normal operating conditions, the flash point of the mineral oil ≥ 150 °C, which is much higher than the designed tolerance temperature of 80 °C); The housing 5 consists of two parts on the left and right and is fastened and connected by bolts. Of course, it can also be disassembled and separated; The inclined plate 11 can be disassembled regularly to clean the magnetorheological fluid attached to it to ensure that the lubricating oil used for lubrication is not contaminated; The oil storage tank 1 is fastened and connected inside the housing 5 in a bolt-removable manner. The oil storage tank 1 has two feed ports, corresponding to the lubricating oil and the magnetorheological fluid respectively, for replenishing the lubricating oil and the magnetorheological fluid. Plug bodies are provided at the feed ports, and the oil storage tank 1 can also be removed as a whole for cleaning during regular maintenance; Both ends of the induction coil can pass through the receiving cylinder 13 and be electrically connected to the circuit board carrying the control system, which is a conventional technology and will not be elaborated here. In this solution, considering the influence of the temperature generated during the operation of the planetary reducer itself on the circuit board, an insulating box 15 for physically isolating the circuit board is separately provided outside the housing 5. The material can be selected from ceramics and fiberglass materials, which are separated from the housing 5 to reduce heat conduction; The power supply can be selected to connect to a main power supply (such as mains electricity) and a backup power supply (such as a generator, a battery pack, etc.). A power supply filtering and voltage stabilizing device can be added to filter the input power supply, remove high-frequency interference, and at the same time ensure that the voltage of the input power supply is stable within the allowable range through the voltage stabilizing device, so as to guarantee the normal operation of subsequent equipment; The control module can be selected as a microcontroller (such as the STM32 series) or a programmable logic controller (PLC), which has multiple input and output interfaces for receiving signals and sending control instructions; The switching module selects a relay K or a contactor suitable for the load current and voltage to realize the on-off switching of two circuits. Each circuit corresponds to a relay or a contactor, and its on-off is controlled by the instruction of the control module, so as to switch the connection state of the circuit; Voltage and current sensors can also be added, which are respectively installed at the input and output ends of the two circuits to monitor the voltage and current values of the circuits in real time, and convert the analog signals into digital signals and then transmit them to the control module; A status sensor can also be added to detect the contact status of the relay or the contactor, ensure the reliable execution of the switching action, and avoid the situation of both circuits being powered on or not powered on at the same time caused by faults such as contact adhesion; Refer to the appendix Figure 4 , S is the power supply, K is the relay, RP is the digital potentiometer, and N1 and N2 are the induction coils forming the first magnetic field and the induction coils forming the second magnetic field respectively; Inclined plate guiding and splash lubrication: The lubricating oil droplets flowing out from the outlet 2 fall on the inclined plate 11. After the magnetic layer 12 separates the magnetic fluid, the pure lubricating oil slides down along the inclined plate under the action of gravity to the top of the planet gear 9 (designed to be flush with the planet gear). When the planet gear rotates at high speed, the oil is thrown out by centrifugal force to form splash lubrication, covering the friction pairs such as the sun gear 10, the planetary bearing and the planetary carrier 7. The structural design with three evenly distributed planet gears can ensure that the oil spreads evenly around under the action of centrifugal force; Optimization of intermittent oil supply frequency: The control system described in this application sets the switching time interval through a timer, and the duration of each oil supply is controlled to be 50 - 80 milliseconds, and the single oil supply amount is accurately controllable. This "small amount and multiple times" oil supply mode can avoid the accumulation problem of traditional oil bath lubrication, and at the same time utilize the stirring action of the rotation of the planet gear to quickly distribute the fresh lubricating oil to each lubrication point to meet the lubrication requirements; Component compatibility: Both the magnetic fluid base fluid and the lubricating oil are of the mineral oil system, and their chemical properties are similar, which can minimize the risk of chemical reaction. In order to avoid chemical reactions, the surface of the magnetic particles can be specially coated (such as oleic acid, silane coupling agent) under normal operation to enhance the dispersion stability in the base fluid and inhibit oxidation decomposition.

[0029] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A self-lubricating planetary reducer, characterized in that: include: An oil storage tank (1) is arranged inside the planetary reducer and contains lubricating oil; An outlet (2) is provided at the bottom of the oil storage tank (1) and communicates with the inside and outside of the oil storage tank (1); A blocking groove (3) is provided at the bottom of the oil storage tank (1) and is connected and coupled with the outlet (2); The receiving groove (4) is provided at the bottom of the oil storage tank (1) and is connected and coupled with the blocking groove; Magnetic fluid, a colloidal solution formed by nano-scale magnetic particles dispersed in a base fluid; Wherein, a first magnetic field and a second magnetic field are respectively arranged at both ends of a virtual line connecting the blocking groove (3) and the containing groove (4); when only the first magnetic field exists near the magnetic fluid, the magnetic fluid flows into the blocking groove (3); when only the second magnetic field exists near the magnetic fluid, the magnetic fluid flows into the containing groove (4); and the magnetic field strength of the first magnetic field has two states, namely: The first magnetic field strength ensures the complete flow of magnetic fluid; The second magnetic field strength causes the magnetic fluid to generate sufficient yield stress to seal the outlet (2).

2. A self-lubricating planetary reducer according to claim 1, characterized in that: The planetary reducer also includes a housing (5), an inner gear ring (6) is arranged in the housing (5), the housing (5) is rotatably connected to a planetary rotating frame (7) and a coupling (8), the planetary rotating frame (7) is rotatably connected to three planetary gears (9) via bearings, the three planetary gears (9) are all meshingly connected to the inner gear ring (6), the coupling (8) is coaxially fixedly connected to a sun gear (10), the sun gear (10) is located between the three planetary gears (9) and meshingly connected to the three planetary gears (9).

3. A self-lubricating planetary reducer according to claim 2, characterized in that: An inclined plate (11) is detachably arranged inside the casing (5) by bolts, a magnetic layer (12) is arranged on a side of the inclined plate (11) facing away from the outlet (2), and an end of the inclined plate (11) close to the planetary gear (9) is flush with the planetary gear (9).

4. A self-lubricating planetary reducer according to claim 2, characterized in that: A receiving tube (13) is symmetrically arranged at two locations of the housing (5), an iron core (14) is fixedly connected inside the receiving tube (13), an induction coil is wound around the iron core (14), and a control system is also arranged on the housing (5), both ends of the two induction coils are connected to the control system, and the on / off state and magnetic field strength of the two induction coils are controlled by the control system.

5. A self-lubricating planetary reducer according to claim 4, characterized in that: The control system includes: A power module, used to provide power; A control module, used to receive signals and send control instructions; The switching module controls the on and off of its circuits through the instructions of the control module, and switches the connection status of the circuits; And a resistance adjustment module, used for adjusting the resistance value in the first magnetic field circuit.

6. A self-lubricating planetary reducer according to claim 5, characterized in that: The switching module is set with a timed switching mode through a timer. When the set time interval is reached, the control module issues a switching command, and uses the intermittent on-off of two relays connected to the two induction coils to control the alternating formation of the first magnetic field and the second magnetic field.

7. The self-lubricating planetary reducer according to claim 5, characterized in that: The resistance adjustment module uses a digital potentiometer RP. After the first magnetic field is formed and reaches the first magnetic field strength, the control module issues an adjustment instruction to reduce the resistance value in the circuit of the first magnetic field, and the first magnetic field transitions from the first magnetic field strength to the second magnetic field strength.

8. A method for self-lubricating a planetary reducer, characterized in that: The planetary reducer used in any one of claims 1 to 7 comprises the following steps: At the set switching time interval, the control module issues a switching instruction. When the switching module receives the switching instruction for the first time, the induction coil forming the first magnetic field is energized, and the induction coil forming the second magnetic field is deenergized. At this moment, the first magnetic field is the first magnetic field strength, and the magnetic field strength is ≤10mT, ensuring that the magnetic fluid flows completely. After the first magnetic field strength is maintained for 50-80 milliseconds, the magnetic fluid completely flows into the blocking groove (3), the control module issues an adjustment instruction, the resistance adjustment module receives the adjustment instruction, and the resistance value in the circuit of the first magnetic field decreases, the first magnetic field transitions from the first magnetic field strength to the second magnetic field strength, the magnetic field strength is ≥50mT, the magnetic fluid generates sufficient yield stress to seal the outlet (2), and the lubricating oil stays inside the oil storage tank (1); The switching module receives the switching instruction for the second time, so that the induction coil forming the first magnetic field is powered off and the induction coil forming the second magnetic field is powered on. At this moment, the magnetic field strength of the second magnetic field is ≤10 mT, ensuring that the magnetic fluid flows completely and the magnetic fluid flows completely into the containing groove (4); The cycle repeats itself.

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