Planetary variable speed brake device

Abstract

The invention relates to the technical field of transmission mechanisms, in particular to a planetary speed change brake device which comprises a gearbox and a gear shaft arranged in the gearbox, the gear shaft is driven by a hydraulic motor, at least one stage of planetary gear train is meshed on the gear shaft, a brake disc is fixedly connected to the periphery of each stage of planetary gear train in the circumferential direction, and the brake disc is arranged on the gearbox. Spiral inclined heat dissipation fins are arranged on the friction face of the brake disc, an annular flow guide groove is formed in the inner wall of the gearbox, and radial gaps are formed between the heat dissipation fins and the annular flow guide groove to form a spiral airflow channel. According to the technical scheme, the hydraulically-driven disc brake assembly is adopted to replace a traditional pneumatic brake, the braking speed is high, an external air source is not needed any more, energy consumption is reduced, the spirally-inclined cooling fins are arranged on the friction face of the brake disc, the cooling fins and the annular flow guide groove in the inner wall of the gearbox form a spiral airflow channel, and the cooling effect is good. The heat dissipation capacity in the braking process is remarkably improved, and the situation that the braking efficiency is reduced due to overheating is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of transmission mechanisms, and particularly to a planetary speed change braking device. Background Art

[0002] Power tongs or iron roughnecks are mainly used in oilfield workover operations as mechanized equipment for screwing on and off oil pipes and similar pipe strings, which can greatly reduce the labor intensity of workover workers and avoid or reduce the occurrence of injury accidents. In order to improve the working efficiency and required high torque of power tongs or iron roughnecks, the transmission of power tongs or iron roughnecks adopts high and low two sets of planetary speed change mechanisms to achieve the speed change function.

[0003] For example, the patent document with the patent publication number: CN116104930A discloses a variable-speed planetary transmission mechanism. Although this solution can achieve the switching between high-speed low-torque and low-speed high-torque through a hydraulic system and a control valve, it does not have a braking function. Since power tongs or iron roughnecks need to ensure their safety and stability during operation, a brake needs to be installed on the basis of speed change.

[0004] At present, most of the planetary speed change devices of power tongs or iron roughnecks use pneumatic brakes for braking. This braking method requires an external power air source, resulting in large energy consumption. Moreover, in actual use, since the compressed air contains moisture, these moisture is extremely easy to accumulate in the airbag of the pneumatic brake and freeze in winter, thus affecting the braking performance.

[0005] Another example is the patent document with the patent publication number: CN118669458A, which discloses a fixed disc brake. Although this solution avoids the problems of large energy consumption, easy water storage and icing, difficult maintenance, and fast aging existing in the use of pneumatic brakes, the existing disc brakes can only be applied to the braking of automobiles, and it is very difficult to apply them to the braking of the planetary speed change devices of power tongs or iron roughnecks, making it difficult for the planetary speed change devices of power tongs or iron roughnecks to get rid of the problems brought by the use of pneumatic brakes. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems in the related technologies to some extent. For this reason, the purpose of the present invention is to provide a planetary speed change braking device to improve the braking efficiency and response speed.

[0007] The purpose of the present invention can be realized by the following technical solutions: A planetary speed change braking device includes a gearbox and a gear shaft disposed inside the gearbox. The gear shaft is driven by a hydraulic motor, and at least one stage of planetary gear train is meshed on the gear shaft. A brake disc is fixedly connected circumferentially to the outer periphery of each stage of the planetary gear train. The friction surface of the brake disc is provided with helically inclined heat dissipation fins. An annular diversion groove is provided on the inner wall of the gearbox. A radial gap is formed between the heat dissipation fins and the annular diversion groove, constituting a spiral air flow channel; A plurality of disc brake assemblies are clamped on the side of the gearbox. Each disc brake assembly includes two oppositely arranged disc brake pads, a double-acting hydraulic cylinder, and a temperature sensor integrated on the inner side of the disc brake pad. The two disc brake pads are respectively fixed to both ends of the piston rod of the double-acting hydraulic cylinder through fixing plates. The disc brake pads move axially along the brake disc after being driven by the double-acting hydraulic cylinder, and the temperature sensor is signal-connected to the hydraulic control system.

[0008] In some embodiments of the present invention, the disc brake pad is composed of a composite friction layer and a metal substrate. The composite friction layer is embedded with honeycomb damping cavities, and the damping cavities are filled with a high-temperature resistant viscoelastic material.

[0009] In some embodiments of the present invention, the planetary gear train is one or a combination of two of a high-speed planetary gear train and a low-speed planetary gear train.

[0010] In some embodiments of the present invention, the brake disc is located between the two disc brake pads.

[0011] In some embodiments of the present invention, the composite friction layer is oppositely arranged with the friction surface of the brake disc, and an adjustable friction pair is formed between the composite friction layer and the friction surface of the brake disc.

[0012] In some embodiments of the present invention, the helically inclined angle of the heat dissipation fins is 15°-45°, and the width of the radial gap is 0.5-2 mm.

[0013] In some embodiments of the present invention, the aperture of the honeycomb damping cavity is 1-3 mm, the high-temperature resistant viscoelastic material filled is silicone rubber or polyurethane, and the thickness of the composite friction layer is 5-10 mm.

[0014] In some embodiments of the present invention, when there are multiple stages of the planetary gear train meshed on the gear shaft, the multiple disc brake assemblies are alternately distributed on both sides of the gearbox or are adjacently arranged on the same side of the gearbox.

[0015] In some embodiments of the present invention, the alternate distribution structure of the multiple disc brake assemblies is: the left disc brake assembly and the right disc brake assembly are installed with a 30°-60° offset along the axis direction of the gearbox.

[0016] In some embodiments of the present invention, a plurality of heat dissipation holes are circumferentially formed on the surface of the brake disc.

[0017] Advantages of the present invention: Compared with the traditional method, the technical solution of the present invention uses a hydraulically driven disc brake assembly to replace the traditional pneumatic brake, with fast braking speed, no longer relying on an external air source, reducing energy consumption, and having spiral inclined heat dissipation fins on the friction surface of the brake disc, forming a spiral air flow channel with the annular flow guide groove on the inner wall of the gearbox, significantly enhancing the heat dissipation ability during the braking process and preventing the braking efficiency from decreasing due to overheating. Brief Description of the Drawings

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] Figure 1 is a schematic cross-sectional structure diagram when the gear shaft meshes with the high-speed planetary gear train in the present invention; Figure 2 is a schematic cross-sectional structure diagram when the gear shaft meshes with the low-speed planetary gear train in the present invention; Figure 3 is a schematic cross-sectional structure diagram when the gear shaft meshes with the high-speed planetary gear train and the low-speed planetary gear train in the present invention; Figure 4 is a side view of the disc brake assembly in the present invention; Figure 5 is a three-dimensional view of the brake disc in the present invention.

[0020] In the figure: 1, gearbox; 2, gear shaft; 3, hydraulic motor; 4, high-speed planetary gear train; 5, brake disc; 501, heat dissipation fins; 502, heat dissipation holes; 6, disc brake assembly; 601, disc brake pad; 602, double-acting hydraulic cylinder; 7, fixing plate; 8, low-speed planetary gear train. Detailed Embodiments

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment 1:

[0022] As Figure 1 , Figure 2 , Figure 3 shown, a planetary speed change braking device includes a gearbox 1 and a gear shaft 2 disposed inside the gearbox 1. The gear shaft 2 is driven by a hydraulic motor 3, and the hydraulic motor 3 can accurately adjust the output speed and torque as needed.

[0023] There is at least one stage of planetary gear train meshed with the gear shaft 2. Generally, to increase the speed ratio range, 2 - 3 stages of planetary gear trains can be configured. Each stage of planetary gear train mainly consists of a sun gear, a planet carrier, planet gears and an internal gear ring. Each component is made of high-strength alloy steel material, and the surface is carburized and quenched, with a hardness reaching HRC58 - 62 to improve wear resistance and service life.

[0024] As Figure 5 As shown, a brake disc 5 is fixedly connected circumferentially on the outer periphery of each stage of planetary gear train. On the friction surface of the brake disc 5, there are spiral inclined heat dissipation fins 501, and 6 - 8 heat dissipation fins 501 are evenly distributed along the radial direction of the brake disc 5. There is an annular flow guiding groove on the inner wall of the transmission 1. A radial gap is formed between the heat dissipation fins 501 and the annular flow guiding groove, constituting a spiral air flow channel. This channel forms a forced air flow circulation when the brake disc 5 rotates at high speed, accelerating heat dissipation.

[0025] As an example, the brake disc 5 is made of a special high-carbon chromium alloy steel (carbon content is about 0.95% - 1.05%). After vacuum quenching treatment, it has high hardness (HRC60 - 65) and excellent heat resistance (can withstand instantaneous high temperatures of 800 - 900 °C).

[0026] As Figure 4 As shown, a plurality of disc brake assemblies 6 are clamped on the side of the transmission 1. Each disc brake assembly 6 includes two relatively arranged disc brake pads 601, a double-acting hydraulic cylinder 602 and a temperature sensor integrated on the inner side of the disc brake pad 601, and the temperature sensor is signal-connected to the hydraulic control system. The two disc brake pads 601 are respectively fixed to both ends of the piston rod of the double-acting hydraulic cylinder 602 through a fixing plate 7. The fixing plate 7 is made of high-strength aluminum alloy material, which is light in weight and high in strength, and has good heat dissipation performance. The disc brake pads 601 move axially along the brake disc 5 after being driven by the double-acting hydraulic cylinder 602 to achieve the braking function.

[0027] As an example, the double-acting hydraulic cylinder 602 adopts a piston structure, with a piston diameter of 50 - 70 mm, a working pressure range of 5 - 20 MPa, and can provide a braking force of 2000 - 8000 N.

[0028] When the system needs to perform variable-speed braking, the hydraulic motor 3 drives the gear shaft 2 to rotate, driving the planetary gear train to operate. The variable-speed process is divided into two main stages: Non-braking stage: The hydraulic control system adjusts the output speed of the hydraulic motor 3 according to the working requirements, so that the gear shaft 2 reaches the predetermined speed. At this time, the brake disc 5 rotates at high speed with the planetary gear train, and the disc brake assembly 6 is in a standby state.

[0029] Braking Phase: When a certain level of planetary gear train is required to output torque and rotational speed, the hydraulic control system sends a command to the corresponding double-acting hydraulic cylinder 602 to increase the hydraulic pressure (rapidly rising to 10 - 15 MPa). The double-acting hydraulic cylinder 602 pushes the disc brake pads 601 towards the brake disc 5. When the friction surface of the disc brake pads 601 contacts the brake disc 5, a frictional torque is generated, immediately braking the brake disc at this level. The planet completes the speed change and outputs the corresponding torque and rotational speed through the gear shaft. Meanwhile, the temperature sensor continuously monitors the temperature of the friction surface. When the temperature exceeds the set threshold (usually 350 °C), the hydraulic system will automatically adjust the pressure to prevent a decrease in braking efficiency and component damage caused by overheating.

[0030] Compared with traditional pneumatic brakes, the planetary speed change braking device in this embodiment uses hydraulic drive instead of a pneumatic system, avoiding the problem of water freezing in compressed air in winter and greatly improving the working reliability in low-temperature environments. Moreover, the braking force provided by the double-acting hydraulic cylinder 602 is much higher than that of an airbag brake, capable of meeting the braking requirements under heavy-duty conditions.

[0031] It should be noted that after the power tong or iron roughneck planetary speed change braking device has been running for a period of time, its connection condition needs to be regularly inspected to ensure that the connection is firm and there is no looseness. It is also necessary to check the wear conditions of the brake disc 5 and the disc brake pads 601, promptly replace severely worn components, and conduct performance tests regularly to ensure that its braking performance and reliability meet the predetermined requirements and satisfy the working needs of the power tong or iron roughneck.

[0032] As an example, as Figure 2 shown, when a first-stage low-speed planetary gear train 8 is meshed on the gear shaft 2, since the low-speed planetary gear train 8 is used to transmit a large torque, the braking device will be more stable and reliable. The low-speed planetary gear train 8 ensures that it will not become disengaged due to excessive torque during braking under the strong frictional force of the disc brake assembly 6, enabling the power tong or iron roughneck to be used in heavy-duty or high-torque transmission occasions. Since the rotational speed of the low-speed planetary gear train 8 is relatively slow, the heat generated and wear during braking are relatively less, thus extending the service life of the braking device and the planetary gear train.

[0033] As an example, as Figure 3As shown, the planetary gear train is one or a combination of two of the high-speed planetary gear train 4 and the low-speed planetary gear train 8. When at least one stage of the high-speed planetary gear train 4 and the low-speed planetary gear train 8 are meshed on the gear shaft 2, the low-speed planetary gear train 8 is arranged below the high-speed planetary gear train 4 through the gear shaft 2. The combination of the high-speed planetary gear train 4 and the low-speed planetary gear train 8 can flexibly adapt to different working conditions and requirements. In occasions where high-speed rotation and quick response are needed, the high-speed planetary gear train 4 can be mainly relied on; while in occasions where large torque transmission and heavy-duty applications are needed, the low-speed planetary gear train 8 can be mainly relied on. By braking the high-speed planetary gear train 4 and the low-speed planetary gear train 8 simultaneously, the braking efficiency can be further improved, ensuring the stable operation of the power tong or the rotary table in complex working conditions, and making the power tong or the rotary table have higher reliability during braking. Embodiment Two:

[0034] Based on Embodiment One, in this embodiment, the disc brake pad 601 is composed of a composite friction layer and a metal substrate. The thickness of the composite friction layer is 5 - 10 mm, and it is embedded with honeycomb damping cavities. The aperture of the damping cavity is 1 - 3 mm, preferably 2 mm, and the porosity is about 30 - 40%. The damping cavity is filled with a high-temperature resistant viscoelastic material, such as modified silicone rubber or polyurethane elastomer, and the temperature resistance can reach 350 - 400 °C.

[0035] As an example, through a hierarchical structure design of the composite friction layer, the friction coefficient changes in a gradient from the outside to the inside. The friction coefficient of the outer layer (in direct contact with the brake disc 5) is relatively high (about 0.42 - 0.45), and the friction coefficient of the inner layer is relatively low (about 0.35 - 0.38). This gradient design can reduce the "chatter" phenomenon during braking, and improve the braking smoothness and comfort.

[0036] As an example, the composite friction layer adopts a ceramic-metal composite material (copper-based ceramic material, Cu-SiC-Al2O3 system), the friction coefficient is in the range of 0.35 - 0.45, and it can still maintain stable performance at high temperatures (above 600 °C).

[0037] In some embodiments of the present invention, the brake disc 5 is located between two disc brake pads 601, the friction surfaces of the composite friction layer and the brake disc 5 are arranged opposite to each other, and an adjustable friction pair is formed between the friction surfaces of the composite friction layer and the brake disc 5. By precisely controlling the contact pressure through the double-acting hydraulic cylinder 602, linear adjustment of the frictional torque can be achieved.

[0038] In some embodiments of the present invention, the spiral inclination angle of the heat dissipation fins 501 is 15° - 45°. Through hydrodynamic calculations and experimental verification, it is shown that the heat dissipation effect is optimal at an angle of 30°, which can increase the heat dissipation efficiency by about 55%. And the width of the radial gap is 0.5 - 2 mm, preferably 1.2 mm. This gap can not only ensure sufficient air flow but also maintain a high air flow velocity, forming a "Venturi effect" to further enhance the heat dissipation performance.

[0039] In some embodiments of the present invention, a plurality of heat dissipation holes 502 are circumferentially formed on the surface of the brake disc 5. The diameter of these heat dissipation holes 502 is 4 - 6 mm, and they are arranged at equal intervals along the radial direction, with a total number of 36 - 48. The heat dissipation holes 502 and the heat dissipation fins 501 work together to form an "internal and external circulation" heat dissipation system: when the brake disc 5 rotates at a high speed, the air flow passing through the heat dissipation holes 502 intersects with the spiral air flow formed by the heat dissipation fins 501 and the annular diversion groove, generating a turbulence effect and significantly improving the heat exchange efficiency. Experimental data shows that this design reduces the temperature rise rate of the brake disc 5 under high-intensity braking conditions by about 35%.

[0040] As an example, the temperature sensors integrated inside the disc brake pads 601 form a precise temperature monitoring network. One or two temperature sensors are embedded in each disc brake pad 601 and are evenly distributed along the radial direction to monitor the temperature distribution in different regions.

[0041] The hydraulic control system implements a three-level braking control strategy based on the temperature data: Conventional braking mode (temperature < 250°C): The double-acting hydraulic cylinder 602 provides full pressure (15 - 20 MPa) to achieve the maximum braking force; Transition braking mode (250°C ≤ temperature < 350°C): The hydraulic system linearly reduces the pressure according to the temperature, and the pressure range is 10 - 15 MPa to balance the braking efficiency and the temperature rise. Embodiment Three:

[0042] Based on Embodiment Two, in this embodiment, when there are multiple planetary gear trains meshed on the gear shaft 2, multiple disc brake assemblies 6 are alternately distributed on both sides of the transmission 1 or are adjacent to each other on the same side of the transmission 1.

[0043] According to the number of stages and layout of the planetary gear train, the following several layout methods of the disc brake assembly 6 can be adopted: Symmetrical layout: For a two-stage planetary gear train, one disc brake assembly 6 is arranged on each side of the brake disc 5 of each stage of the planetary gear train, forming a completely symmetrical structure. This layout method has a uniform braking force distribution but occupies a large space; Staggered arrangement: The alternating distribution structure of multiple disc brake assemblies 6 is as follows: The left disc brake assembly 6 and the right disc brake assembly 6 are installed with a 30° - 60° offset along the axis direction of the transmission 1, and the preferred angle is 45°. This arrangement can reduce the occupation of axial space and avoid the mutual influence of heat between the disc brake assemblies 6. At this time, the braking sequence of the disc brake assemblies 6 on both sides is dynamically adjusted by the hydraulic control system to achieve asymmetric alternating or synchronous braking of multiple brake discs 5. This design can disperse the load during the braking of the power tongs or the iron roughneck, reduce the wear and fatigue of a single component, and also help to improve the reliability and durability of the entire transmission system and extend the service life of the equipment; Multi-point arrangement on the same side: For a three-stage or more planetary gear train, multiple disc brake assemblies 6 can be arranged adjacent to each other on the same side of the transmission 1, and each disc brake assembly 6 is arranged at an interval of 60° - 90°, which not only saves space but also provides sufficient braking torque.

[0044] It should be noted that regardless of which arrangement method is adopted, the brake disc 5 is always located between the two brake pads 601. By adjusting the thrust of the double-acting hydraulic cylinder 602, the brake pads 601 on both sides can be made to contact the brake disc 5 simultaneously or alternately to achieve various braking modes.

[0045] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. 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 a suitable manner in any one or more embodiments or examples.

[0046] The above content is only an example and explanation of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. A planetary variable-speed braking device, comprising a gearbox and a gear shaft disposed inside the gearbox, the gear shaft being driven by a hydraulic motor, characterized in that, At least one stage of planetary gear train is meshed on the gear shaft. A brake disc is fixedly connected to the outer circumference of each stage of the planetary gear train. Spiral inclined heat dissipation fins are arranged on the friction surface of the brake disc. An annular flow guide groove is arranged on the inner wall of the gearbox. A radial gap is formed between the heat dissipation fins and the annular flow guide groove, constituting a spiral air flow channel; A plurality of disc brake assemblies are clamped on the side of the gearbox. Each disc brake assembly includes two oppositely arranged disc brake pads, a double-acting hydraulic cylinder, and a temperature sensor integrated on the inner side of the disc brake pad. The two disc brake pads are respectively fixed to both ends of the piston rod of the double-acting hydraulic cylinder through a fixing plate. The disc brake pads move axially along the brake disc after being driven by the double-acting hydraulic cylinder, and the temperature sensor is signal-connected to the hydraulic control system.

2. The planetary speed change braking device according to claim 1, characterized in that The disc brake pad is composed of a composite friction layer and a metal substrate. The composite friction layer is embedded with honeycomb damping cavities, and the damping cavities are filled with high-temperature resistant viscoelastic materials.

3. A planetary speed change braking device according to claim 1, characterized in that, The planetary gear train is one or a combination of two of a high-speed planetary gear train and a low-speed planetary gear train.

4. A planetary speed change braking device according to claim 1, characterized in that The brake disc is located between the two disc brake pads.

5. A planetary speed change braking device according to claim 2, characterized in that, The composite friction layer is arranged opposite to the friction surface of the brake disc, and an adjustable friction pair is formed between the composite friction layer and the friction surface of the brake disc.

6. A planetary speed change braking device according to claim 1, characterized in that, The spiral inclination angle of the heat dissipation fins is 15°-45°, and the width of the radial gap is 0.5-2 mm.

7. A planetary speed change braking device according to claim 2, characterized in that, The aperture of the honeycomb damping cavity is 1-3 mm, the high-temperature resistant viscoelastic material filled is silicone rubber or polyurethane, and the thickness of the composite friction layer is 5-10 mm.

8. A planetary speed change braking device according to claim 1, characterized in that, When there are multiple stages of the planetary gear train meshed on the gear shaft, the multiple disc brake assemblies are alternately distributed on both sides of the gearbox or are adjacent to each other on the same side of the gearbox.

9. A planetary speed change braking device according to claim 8, characterized in that The alternate distribution structure of the multiple disc brake assemblies is that the left disc brake assembly and the right disc brake assembly are installed with a 30°-60° offset along the axis direction of the gearbox.

10. A planetary speed change braking device according to claim 1, characterized in that, A plurality of heat dissipation holes are circumferentially formed on the surface of the brake disc.

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