Articulation swing excitation decelerator self-circulation cooling device and method

Abstract

This invention discloses a self-circulating cooling device and method for a reducer driven by joint oscillation. The device includes a housing, a gear transmission mechanism, a cooling oil tank, a bidirectional oil intake assembly, a stable oil collection assembly, a cooling chamber, an inertial oil pumping mechanism, and an oil injection channel. The cooling oil tank is located at the lower part of the housing. The bidirectional oil intake assembly intercepts hot oil carried by the forward and reverse motion of the gears, which is then collected in the cooling chamber by the stable oil collection assembly for heat exchange. The inertial oil pumping mechanism then uses the joint oscillation to drive the cooling oil through the oil injection channel to the gear meshing area and the parts to be lubricated, forming a self-circulating cooling loop without an independent pump source. This invention fully utilizes the kinetic energy of joint oscillation, improving the stability of oil intake, collection, and pumping under reciprocating oscillation conditions, and is suitable for the cooling and lubrication of robot joint reducers.

Description

Technical Field

[0001] This invention belongs to the field of joint reducer cooling and lubrication technology, specifically relating to a self-circulating cooling device and method for a reducer subjected to joint swing excitation. Background Technology

[0002] Quadruped robots, humanoid robots, and other electromechanical devices with swing joints typically bear cyclic loads, impact loads, and frequent reversals within a limited installation space. As a joint transmission component, the reducer continuously generates heat in its gear meshing area and support parts during operation. If this heat cannot be dissipated in time, it can easily lead to increased oil temperature, decreased lubrication performance, and accelerated wear of transmission components.

[0003] Existing speed reducers mostly employ oil bath lubrication or splash lubrication, as illustrated in Chinese patent applications CN107532705A and CN209130148U. These methods primarily rely on the continuous rotation of gears to drive oil flow, resulting in limited oil renewal and heat exchange capabilities under low-speed, small-angle reciprocating oscillation conditions. Chinese patent CN207093734U provides a speed reducer lubrication system comprising a speed reducer, an oil pump, and an oil cooler. The oil pump is located outside the housing, and a lubricating oil circulation pipeline is provided between the oil pump and the speed reducer. The oil pump draws lubricating oil from the speed reducer through the inlet pipe and sprays the drawn lubricating oil back into the moving parts within the housing through the return pipe. While this patented technology uses an independent oil pump to improve circulation capacity, it increases the number of drive components, pipelines, energy consumption, and installation space, hindering the miniaturization and integration of articulated speed reducers.

[0004] Furthermore, the joint's oscillation causes internal oil sloshing, and when oil is drawn directly from the internal oil sump, the oil suction port may briefly expose the oil surface, affecting the stability of the oil supply. Therefore, a reducer cooling solution is needed that can adapt to both forward and reverse oscillation, stably collect hot oil, and utilize the joint's own movement to drive oil circulation. Summary of the Invention

[0005] In view of the above, the present invention provides a self-circulating cooling device and method for a reducer excited by joint swinging. The device utilizes the acceleration generated by the reciprocating swinging of the joint to drive the oil to self-circulate inside the reducer, thereby improving the stability of oil intake, collection and pumping under reciprocating swinging conditions, and forming a self-circulating cooling circuit for the oil without setting an independent pump drive source.

[0006] A self-circulating cooling device for a speed reducer with joint swing excitation includes a housing, a gear transmission mechanism, a cooling oil sump, a bidirectional oil intake assembly, a stabilizing oil collection assembly, an oil injection channel, a cooling chamber, and an inertial oil pump mechanism, wherein: The gear transmission mechanism and the cooling oil tank are located inside the housing. The cooling oil tank is located in the low area inside the joint reducer and is used to store circulating oil. The bidirectional oil extraction component is located on the oil throwing path of the gear transmission mechanism and is used to intercept the hot oil liquid driven by the forward and reverse motion of the gear transmission mechanism. The stable oil collection component is located in the outer peripheral area of ​​the gear transmission mechanism and is unidirectionally connected to the cooling chamber. It is used to collect the intercepted hot oil and ensure that there is oil covering near the valve port when the internal oil collection tank shakes. The cooling cavity is used for thermal coupling with the heat dissipation structure outside the shell to cool the internal oil. The inertial oil pump mechanism has its inlet end connected to the cooling chamber and its outlet end connected to the oil injection channel. The reciprocating swing of the joint reducer drives the flow of cooling oil. The oil injection end of the oil injection channel faces the meshing area of ​​the gear transmission mechanism and the parts to be lubricated or cooled.

[0007] Furthermore, the cooling oil pool, bidirectional oil extraction component, stable oil collection component, cooling chamber, inertial oil pumping mechanism, and oil injection channel, together with the gear transmission mechanism, form a self-circulating closed loop with joint swing excitation. The oil in the cooling oil pool is carried by the gear transmission mechanism, intercepted by the bidirectional oil extraction component, enters the stable oil collection component, and then flows into the cooling chamber for heat exchange to form cooling oil. The cooling oil is pumped by the inertial oil pumping mechanism to the oil injection channel and sprayed onto the gear transmission mechanism. After lubrication and heat absorption, it flows back to the cooling oil pool.

[0008] Furthermore, the gear transmission mechanism adopts a planetary gear transmission structure, including a ring gear, a sun gear, and multiple planet gears. When the gear transmission mechanism is working, the planet gears and the ring gear drive the oil in the cooling oil pool to move, and form oil carrying, throwing, or splashing on the tooth surface in and around the meshing area.

[0009] Furthermore, the bidirectional oil extraction assembly includes two sets of oil extraction sections, one set of which is used to extract oil when the gear transmission mechanism moves in the forward direction, and the other set of which is used to extract oil when the gear transmission mechanism moves in the reverse direction. The two sets of oil extraction sections are connected to the stable oil collection assembly through a confluence channel and have a wedge-shaped guide surface that gradually converges towards the confluence channel, and maintain a non-contact gap with the gear transmission mechanism and the housing.

[0010] Furthermore, the stable oil collection assembly includes a manifold channel, an oil collection trough, and a one-way check valve. The manifold channel is connected to the oil intake section. The oil collection trough is used to collect the hot oil flowing in through the manifold channel. It is distributed on the outer periphery of the gear ring of the gear transmission mechanism, the inner side of the housing end cover, or the bottom area of ​​the inner wall of the housing. The one-way check valve is located at the valve port where the oil collection trough connects to the cooling chamber. The two ends of the oil collection trough are higher than the location of the one-way check valve, so that the oil tends to collect near the valve port under the action of gravity or joint swing. The main area in the oil collection trough initially contains basic oil, so that the valve port is kept covered with oil within a specified swing range.

[0011] Furthermore, the stable oil collection assembly also includes a gas-liquid separation and filtration assembly, which includes an expansion chamber, a filter screen, an exhaust port, and a magnetic chip collector. The expansion chamber is located at the end of the oil collection tank, and the exhaust port is located at the top of the expansion chamber and communicates with the internal space of the gear transmission mechanism. After the hot oil enters the expansion chamber, the flow rate decreases, and the entrained air bubbles separate upward and enter the internal space of the gear transmission mechanism through the exhaust port. The filter screen is located in the expansion chamber to intercept particulate matter in the oil, and the magnetic chip collector is located in the oil collection tank and upstream of the valve port to adsorb ferromagnetic wear debris in the oil.

[0012] Furthermore, the cooling chamber adopts an annular groove structure and is located on the outer side of the gear ring of the gear transmission mechanism, the inner side of the housing end cover, or the outer peripheral area of ​​the inner wall of the housing. The cavity wall of the cooling chamber is in direct contact with, connected to, or integrally formed with the heat dissipation structure outside the housing, so that the oil in the cavity can transfer heat to the outside through the housing wall and be cooled.

[0013] Furthermore, the inertial pump mechanism is composed of multiple sets of inertial pump assemblies evenly distributed along the inner circumference of the cooling chamber. Each inertial pump assembly includes a pump chamber, an inertial mass plunger assembly, and an elastic element. The inertial mass plunger assembly divides the entire pump chamber into two working chambers, left and right, and moves back and forth along the pump chamber under the action of the acceleration component generated by the joint swing, so that the two working chambers alternately draw in and discharge oil. The inertial mass plunger assembly includes an inertial sliding element and counterweights on its left and right sides. The elastic element is set on the counterweights to reset the inertial mass plunger assembly to the middle position of the pump chamber after the acceleration decreases. Each working chamber is connected to the cooling chamber through the suction check valve at the top oil inlet end and to the corresponding oil injection channel through the discharge check valve at the bottom oil outlet end.

[0014] Furthermore, the movement direction of each inertial pump assembly is parallel to the acceleration direction during the joint swing motion. The mass of the counterweight and the stiffness of the elastic element are positively correlated with the magnitude of the acceleration in the corresponding direction, and the acceleration start threshold of the inertial pump assembly is less than the swing excitation acceleration in the corresponding direction.

[0015] A self-circulating cooling method for a reducer with joint swing excitation includes the following steps: Step S1: Before starting the joint reducer, inject oil into the cooling oil pool, the oil collection tank of the stabilizing oil collection assembly, and the cooling chamber; Step S2: After the joint reducer is started, the gear meshing inside the gear transmission mechanism generates heat, and hot oil is thrown out when rotating in the forward and reverse directions. The hot oil is intercepted by the bidirectional oil collection component and enters the oil collection tank through the confluence channel. Step S3: The oil stabilization assembly filters and separates the hot oil into gas and liquid, and then the oil enters the cooling chamber through the check valve, where it exchanges heat with the surrounding heat-conducting ring, joint connecting rod or ambient air to form cooling oil. Step S4: Using the acceleration generated by the reciprocating swing of the joint, multiple sets of inertial mass plunger assemblies reciprocate in the pump chamber, and through the alternating oil intake and discharge of the two working chambers, the cooling oil is distributed through the oil injection channel and sprayed into the meshing area of ​​the gear transmission mechanism. Step S5: After lubrication and heat absorption, the cooling oil is returned to the cooling oil pool, and steps S2 to S5 are repeated to achieve oil self-circulation for joint swing excitation.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: 1. This invention utilizes the acceleration generated by the reciprocating swing of a joint to drive an inertial pump oil mechanism, eliminating the need for a separate pump drive source, which helps reduce additional energy consumption and installation space.

[0017] 2. In this invention, the two oil extraction points correspond to the forward and reverse movements of the gear transmission mechanism, respectively, and can intercept hot oil during the two strokes of the joint's reciprocating swing.

[0018] 3. In this invention, the two ends of the oil collection tank are higher than the one-way valve port, and the base oil is kept in the oil collection tank, which can reduce the possibility of gas being sucked into the valve port or oil supply interruption caused by the internal oil sloshing.

[0019] 4. In this invention, the inertial pump assembly can complete oil suction and discharge in both directions of the reciprocating movement of the inertial mass plunger assembly, and multiple pump assemblies can respond to oscillating acceleration in different directions.

[0020] 5. In this invention, the gas-liquid separation and filtration component can reduce the bubbles and impurities entering the cooling chamber and the inertial pump oil mechanism; after the cooling chamber exchanges heat with the heat dissipation structure outside the shell, the oil is sent to the gear meshing area through the oil injection channel, which is conducive to forming a stable cooling and lubrication cycle. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the self-circulating cooling device for the reducer of the joint swing excitation according to the present invention.

[0022] Figure 2 This is a schematic diagram of the inertial pump oil mechanism.

[0023] Figure 3 This is a schematic diagram of the knee joint swing trajectory of a quadruped robot.

[0024] Figure 4 This is a schematic diagram showing the direction of the inertial pump oil mechanism's movement in response to the direction of the joint's oscillation acceleration.

[0025] Figure 5 This is a schematic cross-sectional view of the bidirectional oil extraction assembly and the stable oil collection assembly.

[0026] Figure 6This is a schematic diagram of the self-circulating cooling method for the reducer of the joint swing excitation of the present invention.

[0027] In the diagram: 1—Inertial pump oil mechanism, 2—Injection channel, 3—Gear transmission mechanism, 4—Bidirectional oil intake assembly, 5—Stable oil collection assembly, 6—Housing, 7—Cooling chamber, 8—Cooling oil pool, 101—Low friction pump chamber wall, 102—First working chamber, 103—Elastic element, 104—Second working chamber, 105—Inertial sliding element, 106—Counterweight, 107—First suction check valve, 108—Second suction check valve, 109—First discharge check valve, 110—Second discharge check valve, 401—First oil intake section, 402—Second oil intake section, 501—Combination channel, 502—Oil collection trough, 503—Expansion chamber, 504—Exhaust port, 505—Filter screen, 506—Magnetic chip collector, 507—One-way check valve. Detailed Implementation

[0028] To describe the present invention in more detail, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1 As shown, this embodiment provides a self-circulating cooling device for a reducer with joint swing excitation, including an inertial oil pump mechanism 1, an oil injection channel 2, a gear transmission mechanism 3, a bidirectional oil intake assembly 4, a stable oil collection assembly 5, a housing 6, a cooling chamber 7, and a cooling oil pool 8. The gear transmission mechanism 3 and the cooling oil pool 8 are located inside the housing 6. The cooling oil pool 8 is located in the lower region inside the reducer and is used to store circulating oil.

[0030] In this embodiment, the gear transmission mechanism 3 is a planetary gear transmission mechanism, including a ring gear, a sun gear, and multiple planet gears. When the gear transmission mechanism 3 is working, the tooth surface drives the oil in the cooling oil sump 8 to move, and forms oil carrying, throwing, or splashing on the tooth surface in and around the meshing area. Other gear transmission mechanisms that can drive the oil and form an oil throwing path during movement can also adopt the cooling structure of the present invention.

[0031] The bidirectional oil intake assembly 4 is located on the oil throwing path of the gear transmission mechanism 3, the stable oil collection assembly 5 is located in the outer peripheral area of ​​the gear transmission mechanism 3, and the cooling chamber 7 is located in the outer peripheral area of ​​the housing 6. The oil inlet of the inertial oil pumping mechanism 1 is connected to the cooling chamber 7, and the oil outlet is connected to the oil injection channel 2. The oil injection end of the oil injection channel 2 faces the meshing area of ​​the gear transmission mechanism 3, and may also face the support part if necessary, thus forming the following circulation path: the oil in the cooling oil pool 8 is carried by the gear transmission mechanism 3, intercepted by the bidirectional oil intake assembly 4, enters the stable oil collection assembly 5, and then flows into the cooling chamber 7; the oil after heat exchange is pumped by the inertial oil pumping mechanism 1 to the oil injection channel 2 and sprayed onto the gear transmission mechanism 3, and after completing lubrication and heat absorption, it flows back to the cooling oil pool 8.

[0032] like Figure 5 As shown, the bidirectional oil extraction component 4 can be configured as a bidirectional oil scraping structure, including a first oil extraction part 401 and a second oil extraction part 402. The first oil extraction part 401 is oriented towards the direction of oil ejection when the gear transmission mechanism 3 moves in the forward direction, and the second oil extraction part 402 is oriented towards the direction of oil ejection when the gear transmission mechanism 3 moves in the reverse direction. The oil extraction ends of the first oil extraction part 401 and the second oil extraction part 402 are located in the corresponding oil ejection paths and maintain a non-contact gap with the moving tooth surface and the adjacent housing wall surface to avoid friction or interference with the transmission components.

[0033] The first oil intake section 401 and the second oil intake section 402 each have a wedge-shaped guide surface that gradually converges towards the confluence channel 501. After the hot oil ejected by the gear transmission mechanism 3 comes into contact with the wedge-shaped guide surface, it converges towards the confluence channel 501 under the constraint of the guide surface. During forward movement, the first oil intake section 401 is the main oil intake section, and during reverse movement, the second oil intake section 402 is the main oil intake section, thereby adapting to the reciprocating swing of the joint.

[0034] The stabilizing oil collection assembly 5 includes a manifold 501, an oil collection trough 502, and a one-way check valve 507 located at the one-way valve port. The oil collection trough 502 can be a semi-annular, arc-shaped, or multi-segment arc-shaped cavity, located on the outer periphery of the gear ring, the inner side of the end cap, or the bottom area of ​​the inner wall of the housing. The two ends of the oil collection trough 502 are higher than the location of the one-way check valve 507, causing the oil to tend to collect near the valve port under the action of gravity and joint oscillation. During assembly or initialization, the main area of ​​the oil collection trough 502 contains basic oil, ensuring that the one-way valve port is covered with oil within a specified oscillation range. The one-way check valve 507 allows oil to flow from the stabilizing oil collection assembly 5 to the cooling chamber 7 and restricts the backflow of oil.

[0035] The stable oil collection assembly 5 can also be equipped with a gas-liquid separation and filtration assembly, which includes an expansion chamber 503, an exhaust port 504, a filter screen 505, and a magnetic chip collector 506. When hot oil enters the expansion chamber 503, its flow rate decreases, entraining air bubbles that separate upwards and enter the internal space of the gear transmission mechanism 3 through the exhaust port 504. The filter screen 505 is used to intercept larger particles, and the magnetic chip collector 506 is located upstream of the one-way valve port to adsorb ferromagnetic wear debris from the oil.

[0036] The cooling chamber 7 adopts an annular groove structure and is located on the outer side of the gear ring, the inner side of the end cap, or the outer periphery of the shell 6. The cooling chamber 7 forms a heat exchange channel along the outer periphery of the shell 6. Its chamber wall is in direct contact, connected, or integrally formed with the heat dissipation structure outside the shell, such as the heat conduction ring and the joint connecting rod, so that the hot oil entering the cooling chamber 7 can transfer heat to the outside through the shell wall. The cooling chamber 7 also provides cooling oil for the inertial oil pumping mechanism 1, while the stable oil collecting assembly 5 provides a relatively stable oil suction space for the cooling chamber, preventing the inertial oil pumping mechanism 1 from directly sucking oil from the swaying cooling oil pool 8.

[0037] The inertial pump oil mechanism 1 consists of multiple sets of inertial pump assemblies evenly distributed around the circumference of the cooling chamber 7, such as... Figure 2 As shown, each inertial pump assembly includes a pump chamber defined by a low-friction pump chamber wall 101, a first working chamber 102, an elastic element 103, a second working chamber 104, and an inertial mass plunger assembly. The inertial mass plunger assembly includes an inertial slider 105 and a counterweight 106 (or the inertial slider 105 and the counterweight 106 are integrally formed), and divides the pump chamber into the first working chamber 102 and the second working chamber 104. The elastic element 103 is disposed on both sides of the inertial mass plunger assembly to return it to its original position towards the center of the pump chamber after the acceleration decreases.

[0038] The first working chamber 102 is connected to the cooling chamber 7 via the first suction check valve 107 and to the fuel injection channel 2 via the first discharge check valve 109; the second working chamber 104 is connected to the cooling chamber 7 via the second suction check valve 108 and to the fuel injection channel 2 via the second discharge check valve 110. When the inertial mass plunger assembly moves towards the second working chamber 104, the volume of the second working chamber 104 decreases and discharges oil, while the volume of the first working chamber 102 increases and draws in oil; when the inertial mass plunger assembly moves towards the first working chamber 102, the first working chamber 102 discharges oil, and the second working chamber 104 draws in oil. Therefore, the inertial mass plunger assembly can complete the pumping process in both directions of movement.

[0039] like Figure 3 As shown, the quadruped robot's knee joint forms a reciprocating swing trajectory during flexion and extension, and the reducer housing generates acceleration with varying direction and magnitude over time as the joint moves. Figure 4 As shown, multiple representative acceleration directions a1~a5 can be selected from the joint swing trajectory, and multiple sets of inertial pump assemblies are arranged circumferentially along the cooling chamber 7. The movement direction of each set of inertial pump assemblies is parallel or substantially parallel to the corresponding representative acceleration direction. Thus, when the joint moves to different positions, at least one set of inertial pump assemblies can obtain an effective acceleration component along its movement direction.

[0040] Each inertial pump assembly can be configured with inertial mass and centering elastic element stiffness according to the magnitude of acceleration in the corresponding direction. When the acceleration in the corresponding direction is large, the inertial mass and / or elastic element stiffness can be increased accordingly to balance pumping capacity and reset stability. At the same time, by controlling the inertial mass, elastic element preload, elastic element stiffness, and sliding resistance, the acceleration start-up threshold of each inertial pump assembly can be kept lower than the oscillating excitation acceleration under the corresponding operating condition.

[0041] The oil discharged by the inertial pump oil mechanism 1 enters the oil injection channel 2. The oil injection channel 2 can be composed of an annular main channel and multiple oil injection branches, with the oil injection end facing the meshing area of ​​the gear transmission mechanism 3. After the oil is injected into the meshing area, it forms a lubricating oil film and carries away the heat. Then, under the action of gravity, gear movement and housing flow, it returns to the cooling oil pool 8.

[0042] like Figure 6 As shown, the self-circulating cooling method of this embodiment includes the following steps.

[0043] Step S1: Before starting or during initialization of the reducer, add oil to the cooling oil sump 8, the oil collection tank 502 and the cooling chamber 7. The oil collection tank 502 retains the base oil so that the area near the check valve port is in an oil-immersed state.

[0044] Step S2: After the reducer is running, the gear meshing of the gear transmission mechanism 3 generates heat and throws out hot oil during forward and reverse motion; the hot oil is intercepted by the first oil taking part 401 and the second oil taking part 402 respectively, and enters the oil collecting tank 502 through the confluence channel 501.

[0045] Step S3: The hot oil is filtered by the filter screen 505 in the stable oil collection component 5, the magnetic chip collector 506 collects the chips, and gas-liquid separation is carried out in the expansion cavity 503. Then, it enters the cooling cavity 7 through the one-way check valve 507, and exchanges heat with the surrounding heat-conducting ring, joint connecting rod or ambient air to form cooling oil.

[0046] Step S4: The acceleration generated by the reciprocating swing of the joint drives multiple sets of inertial mass plunger assemblies to move back and forth. The first working chamber 102 and the second working chamber 104 alternately draw in and discharge oil, and distribute the heat-exchanged oil through the oil injection channel 2 and spray it into the meshing area of ​​the gear transmission mechanism 3.

[0047] Step S5: After lubrication and heat absorption, the oil flows back to the cooling oil pool 8, and steps S2 to S5 are repeated to form a self-circulation of oil for joint oscillation excitation.

[0048] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. Those skilled in the art can readily make various modifications to the above embodiments and apply the general principles described herein to other embodiments without creative effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made to the present invention by those skilled in the art based on the disclosure thereof should be within the scope of protection of the present invention.

Claims

1. A self-circulating cooling device for a reducer excited by joint oscillation, characterized in that, It includes a housing, gear transmission mechanism, cooling oil sump, bidirectional oil intake assembly, stable oil collection assembly, oil injection channel, cooling chamber, and inertial oil pump mechanism, wherein: The gear transmission mechanism and the cooling oil tank are located inside the housing. The cooling oil tank is located in the low area inside the joint reducer and is used to store circulating oil. The bidirectional oil extraction component is located on the oil throwing path of the gear transmission mechanism and is used to intercept the hot oil liquid driven by the forward and reverse motion of the gear transmission mechanism. The stable oil collection component is located in the outer peripheral area of ​​the gear transmission mechanism and is unidirectionally connected to the cooling chamber. It is used to collect the intercepted hot oil and ensure that there is oil covering near the valve port when the internal oil collection tank shakes. The cooling cavity is used for thermal coupling with the heat dissipation structure outside the shell to cool the internal oil. The inertial oil pump mechanism has its inlet end connected to the cooling chamber and its outlet end connected to the oil injection channel. The reciprocating swing of the joint reducer drives the flow of cooling oil. The oil injection end of the oil injection channel faces the meshing area of ​​the gear transmission mechanism and the parts to be lubricated or cooled.

2. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 1, characterized in that: The cooling oil pool, bidirectional oil extraction component, stable oil collection component, cooling chamber, inertial oil pumping mechanism, and oil injection channel, together with the gear transmission mechanism, form a self-circulating closed loop with joint swing excitation. The oil in the cooling oil pool is carried by the gear transmission mechanism, intercepted by the bidirectional oil extraction component, enters the stable oil collection component, and then flows into the cooling chamber for heat exchange to form cooling oil. The cooling oil is pumped by the inertial oil pumping mechanism to the oil injection channel and sprayed onto the gear transmission mechanism. After lubrication and heat absorption, it flows back to the cooling oil pool.

3. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 1, characterized in that: The gear transmission mechanism adopts a planetary gear transmission structure, including a gear ring, a sun gear and multiple planet gears. When the gear transmission mechanism is working, the planet gears and the gear ring drive the oil in the cooling oil pool to move, and form oil carrying, throwing or splashing on the tooth surface in the meshing area and its surroundings.

4. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 1, characterized in that: The bidirectional oil extraction assembly includes two sets of oil extraction sections. One set of oil extraction sections is used to extract oil when the gear transmission mechanism moves in the forward direction, and the other set of oil extraction sections is used to extract oil when the gear transmission mechanism moves in the reverse direction. The two sets of oil extraction sections are connected to the stable oil collection assembly through a confluence channel and have a wedge-shaped guide surface that gradually converges towards the confluence channel, and maintain a non-contact gap with the gear transmission mechanism and the housing.

5. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 4, characterized in that: The stable oil collection assembly includes a manifold, an oil collection trough, and a one-way check valve. The manifold is connected to the oil intake section. The oil collection trough is used to collect the hot oil flowing in through the manifold. It is distributed on the outer periphery of the gear ring of the gear transmission mechanism, the inner side of the housing end cover, or the bottom area of ​​the inner wall of the housing. The one-way check valve is located at the valve port where the oil collection trough connects to the cooling chamber. The two ends of the oil collection trough are higher than the location of the one-way check valve, so that the oil tends to collect near the valve port under the action of gravity or joint swing. The main area in the oil collection trough initially contains basic oil, so that the valve port is kept covered with oil within a specified swing range.

6. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 5, characterized in that: The stable oil collection assembly also includes a gas-liquid separation and filtration assembly, which includes an expansion chamber, a filter screen, an exhaust port, and a magnetic chip collector. The expansion chamber is located at the end of the oil collection tank, and the exhaust port is located at the top of the expansion chamber and communicates with the internal space of the gear transmission mechanism. After the hot oil enters the expansion chamber, the flow rate decreases, and the entrained air bubbles separate upward and enter the internal space of the gear transmission mechanism through the exhaust port. The filter screen is located in the expansion chamber to intercept particulate matter in the oil, and the magnetic chip collector is located in the oil collection tank and upstream of the valve port to adsorb ferromagnetic wear debris in the oil.

7. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 1, characterized in that: The cooling chamber adopts an annular groove structure and is located on the outer side of the gear ring of the gear transmission mechanism, the inner side of the housing end cover, or the outer peripheral area of ​​the inner wall of the housing. The cavity wall of the cooling chamber is in direct contact with, connected to, or integrally formed with the heat dissipation structure outside the housing, so that the oil in the cavity can transfer heat to the outside through the housing wall and be cooled.

8. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 1, characterized in that: The inertial pump mechanism consists of multiple inertial pump assemblies evenly distributed circumferentially along the inner side of the cooling chamber. Each inertial pump assembly includes a pump chamber, an inertial mass plunger assembly, and an elastic element. The inertial mass plunger assembly divides the entire pump chamber into two working chambers, left and right, and moves back and forth along the pump chamber under the action of the acceleration component generated by the joint swing, so that the two working chambers alternately draw in and discharge oil. The inertial mass plunger assembly includes an inertial sliding element and counterweights on its left and right sides. The elastic element is set on the counterweights to reset the inertial mass plunger assembly to the middle position of the pump chamber after the acceleration decreases. Each working chamber is connected to the cooling chamber through the suction check valve at the top oil inlet end and to the corresponding oil injection channel through the discharge check valve at the bottom oil outlet end.

9. The self-circulating cooling device for the reducer of the joint swing excitation according to claim 8, characterized in that: The movement direction of each inertial pump assembly is parallel to the acceleration direction during the joint swing motion. The mass of the counterweight and the stiffness of the elastic element are positively correlated with the magnitude of the acceleration in the corresponding direction, and the acceleration start threshold of the inertial pump assembly is less than the swing excitation acceleration in the corresponding direction.

10. A method for self-circulating cooling of a reducer subjected to joint oscillation excitation, based on the self-circulating cooling device for a reducer subjected to joint oscillation excitation as described in any one of claims 1 to 9, the method comprising the following steps: Step S1: Before starting the joint reducer, inject oil into the cooling oil pool, the oil collection tank of the stabilizing oil collection assembly, and the cooling chamber; Step S2: After the joint reducer is started, the gear meshing inside the gear transmission mechanism generates heat, and hot oil is thrown out when rotating in the forward and reverse directions. The hot oil is intercepted by the bidirectional oil collection component and enters the oil collection tank through the confluence channel. Step S3: The oil stabilization assembly filters and separates the hot oil into gas and liquid, and then the oil enters the cooling chamber through the check valve, where it exchanges heat with the surrounding heat-conducting ring, joint connecting rod or ambient air to form cooling oil. Step S4: Using the acceleration generated by the reciprocating swing of the joint, multiple sets of inertial mass plunger assemblies reciprocate in the pump chamber, and through the alternating oil intake and discharge of the two working chambers, the cooling oil is distributed through the oil injection channel and sprayed into the meshing area of ​​the gear transmission mechanism. Step S5: After lubrication and heat absorption, the cooling oil is returned to the cooling oil pool, and steps S2 to S5 are repeated to achieve oil self-circulation for joint swing excitation.

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