Tightening device

Abstract

The invention provides a tightening device, which belongs to the field of mechanical assembly and comprises a cylindrical shell, a first transmission shaft, a planetary gear set, a second transmission shaft, a first assembly sleeve and a second assembly sleeve. The planetary gear set is arranged in the cylindrical shell, and at least part of the second transmission shaft is arranged in the cylindrical shell; the planetary gear set is connected with the second transmission shaft and used for switching the rotating direction of the second transmission shaft; the first assembly sleeve is arranged on the second transmission shaft; the first assembly sleeve is used for sleeving a nut; the second transmission shaft comprises a hollow cavity; the first transmission shaft penetrates through the cylindrical shell and is connected with the planetary gear set, and the first transmission shaft further penetrates through the planetary gear set and is connected with the first assembly sleeve in the through cavity; the first transmission shaft is used for receiving external driving input; the second assembly sleeve is used for sleeving a bolt; by means of the tightening device, the problems that in an existing vehicle assembling scene, a traditional tightening tool is limited in space and low in assembling efficiency can be at least solved.

Description

Technical Field

[0001] This invention relates to the field of mechanical assembly technology, and in particular to a tightening device. Background Technology

[0002] Connecting pairs are commonly used fasteners that require torque to tighten the bolts and nuts in them to ensure the connection effect. In some scenarios, it is necessary to operate the bolts and nuts from the same side of the workpieces being connected.

[0003] In related technologies, two open-end wrenches are used, one for fixing the bolt and the other for turning the nut, to achieve the fastening effect between the bolt and nut and the connected workpiece; However, traditional tightening tools such as open-end wrenches require a large working space, which limits their use in confined spaces such as vehicle assembly. Furthermore, since they are located on the same side of the workpieces being connected, the rotation of the two wrenches can interfere with each other, affecting assembly efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a tightening device to at least solve the problem that traditional tightening tools are limited in space and have low assembly efficiency in current vehicle assembly scenarios.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: The present invention provides a tightening device, the tightening device comprising a cylindrical housing, a first drive shaft, a planetary gear set, a second drive shaft, a first mounting sleeve, and a second mounting sleeve; The planetary gear set is disposed within the cylindrical housing, and at least a portion of the second drive shaft is disposed within the cylindrical housing; the planetary gear set is connected to the second drive shaft, and the planetary gear set is used to switch the rotation direction of the second drive shaft; the first mounting sleeve is disposed on the second drive shaft; the first mounting sleeve is used to engage with a nut; The second drive shaft includes a hollow cavity, the diameter of which is larger than the outer diameter of the second assembly sleeve; The first drive shaft passes through the cylindrical housing and is connected to the planetary gear set. The first drive shaft also passes through the planetary gear set and is connected to the first assembly sleeve in the hollow cavity. The first drive shaft is used to receive external drive input. The inner diameter of the first assembly sleeve is larger than the outer diameter of the second assembly sleeve. The first assembly sleeve is used to mate with bolts.

[0006] Optionally, the planetary gear set includes a sun gear, planet gears, a planet carrier, and an internal gear ring; The sun gear is connected to the first drive shaft, the sun gear meshes with at least two planet gears, the planet gears also mesh with the internal gear ring, and the internal gear ring is connected to the second drive shaft; The planetary carrier includes a first connecting part, a second connecting part, and a movable block; the first connecting part is connected to the planetary gear, and the second connecting part is used to connect the first connecting part; the movable block is used to connect the second connecting part and the planetary gear, or to connect the second connecting part and the cylindrical shell.

[0007] Optionally, the end face of the cylindrical shell is provided with a first fixing hole, the end face of the planetary gear is provided with a second fixing hole, and the movable block is disposed at the second connecting part; The movable block has a switchable first state and a second state; in the first state, the movable block extends into the first fixing hole to connect the cylindrical housing and the second connecting part; in the second state, the movable block extends into the second fixing hole to connect the second connecting part and the planetary gear.

[0008] Optionally, the tightening device may further include a sensor and a controller; The sensor is used to acquire the real-time torque of the first assembly sleeve, and the controller is used to set the movable block to the second state when the real-time torque is greater than or equal to a preset torque threshold, and to set the movable block to the first state when the real-time torque is less than the preset torque threshold.

[0009] Optionally, the first drive shaft is coaxially arranged with the sun gear, and the first drive shaft is fixedly connected to the sun gear; the first drive shaft passes through the sun gear along the axial direction of the sun gear, and is connected to the second assembly sleeve in the hollow cavity; The first connecting part is coaxially arranged with the planetary gear, and the first connecting part is rotatably connected to the planetary gear; the second connecting part connects the first connecting parts on two adjacent planetary gears.

[0010] Optionally, there are three planetary gears, and the lines connecting the axes of the planetary gears form an equilateral triangle, with the axis of the sun gear located at the geometric center of the equilateral triangle.

[0011] Optionally, a countersunk hole is provided on the side of the second drive shaft near the internal gear ring. The countersunk hole communicates with the through cavity. The outer diameter of the internal gear ring matches the diameter of the countersunk hole. The countersunk hole is used to connect with the internal gear ring.

[0012] Optionally, the tightening device further includes a floating joint; The first assembly sleeve is disposed at the end of the second drive shaft opposite to the planetary gear set via the floating joint; The floating joint includes multiple elastic elements and a third connecting part; One end of the elastic element is connected to the end of the second drive shaft away from the planetary gear set, and the other end of the elastic element is connected to the third connecting part; the third connecting part is used to connect the first assembly sleeve.

[0013] Optionally, a mounting seat is provided at one end of the second drive shaft near the floating joint. The mounting seat communicates with the through cavity. The size and shape of the mounting seat match the third connecting part. One end of the elastic member is connected to the bottom surface of the mounting seat, and the other end of the elastic member is connected to the third connecting part.

[0014] Optionally, the second drive shaft includes a first part and a second part along the axial direction; the inner wall of the cylindrical shell is provided with a protruding structure along the circumferential direction; The diameter of the first part is larger than the diameter of the second part. The first part is located inside the cylindrical housing near one end of the planetary gear set and abuts against the protruding structure.

[0015] Compared with the prior art, the tightening device of the present invention has the following advantages: The tightening device of the present invention operates the nut and bolt from the same side of the connected workpieces through a first fitting sleeve and a second fitting sleeve, respectively. The inner diameter of the first fitting sleeve is larger than the outer diameter of the second fitting sleeve, allowing the second fitting sleeve to extend out of the hollow cavity and pass through the first fitting sleeve. On the one hand, this arrangement reduces the working space of the tightening device, thereby adapting to assembly operations in confined spaces. On the other hand, it also avoids interference between the first and second fitting sleeves when operating the bolt and nut. The second fitting sleeve is directly connected to the first drive shaft, enabling it to have the same rotational speed as the first drive shaft. The first fitting sleeve is indirectly connected to the first drive shaft in sequence through a planetary gear set and a second drive shaft. Through the planetary gear set, the tightening device can change the rotation direction of the first fitting sleeve, thereby making the rotation directions of the first and second fitting sleeves different. As a result, the nut and bolt can simultaneously receive torques in different directions, thus efficiently achieving the tightening of the nut and bolt. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is an exploded schematic diagram of a tightening device provided in an embodiment of the present invention; Figure 2 This is an isometric schematic diagram of the cylindrical housing included in the tightening device provided in the embodiment of the present invention; Figure 3 This is an isometric schematic diagram of the first transmission shaft included in the tightening device provided in the embodiment of the present invention; Figure 4 This is an isometric schematic diagram of the planetary gear set included in the tightening device provided in the embodiment of the present invention; Figure 5 This is an isometric schematic diagram of the second transmission shaft included in the tightening device provided in the embodiment of the present invention; Figure 6 This is an isometric schematic diagram of the first mounting sleeve included in the tightening device provided in the embodiment of the present invention; Figure 7 This is an isometric schematic diagram of the second mounting sleeve included in the tightening device provided in the embodiment of the present invention; Figure 8 This is an isometric schematic diagram of the floating joint included in the tightening device provided in the embodiment of the present invention.

[0017] Explanation of reference numerals in the attached figures: 1. Cylindrical shell; 2. First drive shaft; 3. Planetary gear set; 4. Second drive shaft; 5. First mounting sleeve; 6. Second mounting sleeve; 7. Floating joint; 11. First fixing hole; 12. Through hole; 13. Protruding structure; 21. Fourth connecting part; 22. Fifth connecting part; 31. Sun gear; 32. Planet gear; 33. Planet carrier; 34. Internal gear ring; 321. Second fixing hole; 331. First connecting part; 332. Second connecting part; 333. Movable block; 41. Hollow cavity; 42. Countersunk hole; 43. Mounting base; 44. First part; 45. Second part; 51. Sixth connecting part; 52. First sleeve part; 61. Seventh connecting part; 62. Second sleeve part; 71. Elastic element; 72. Third connecting part. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The terms "first," "second," etc., used in the specification and claims of this invention are used to distinguish similar objects and are not used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, the first object can be one or more.

[0020] It should be understood that the phrase "some embodiments" throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of the invention. Therefore, "some embodiments" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0021] The tightening device provided by the present invention will be described in detail below through specific embodiments.

[0022] First, the technical background of the present invention will be explained as follows: Connecting pairs are common fasteners used in assembly. Their main components include bolts and nuts. By clamping the connected workpieces from both sides with the bolt's nut and nut respectively, a secure fastening effect is ensured. Tightening the bolt and nut requires providing torque to the nut, causing it to rotate along the threads of the bolt. This brings the nut and bolt's nut closer together, clamping the connected workpieces. In vehicle assembly scenarios (e.g., installing shock absorbers), due to bolt installation direction limitations, the bolt and nut need to be operated from the same side of the connected workpieces. In this case, the bolt's shank end (the end away from the nut) can be machined into a shape that easily accepts torque (e.g., a hexagonal shaft with a hexagonal radial cross-section). To operate the bolt and nut, related technologies use two open-end wrenches: one to hold the bolt's shank end in place, and the other to engage the nut and provide torque through rotation, causing the nut to move along the bolt's threads towards the bolt's nut, clamping the connected workpieces. The above approach has at least the following problems: The space in the vehicle assembly scene is relatively small, and the rotation space of the open-end wrench is limited by other workpieces in the vehicle, making continuous rotation impossible. Often, the operator needs to rotate the wrench to a certain angle, separate the open-end wrench and the nut, select a suitable angle to insert the nut into the open-end wrench, and then rotate the open-end wrench again. This not only results in low assembly efficiency but also makes it difficult to provide continuous and sufficient torque to the nut, making it difficult to guarantee the tightening quality. Since the two open-end wrenches need to operate the bolt and nut from the same side of the connected workpiece, the two open-end wrenches will also interfere with each other, which will also lead to the problem of the open-end wrench not being able to rotate continuously, affecting the assembly quality and assembly efficiency.

[0023] To at least solve the above problems, in conjunction with reference Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 and Figure 7 The present invention provides a tightening device. Figure 1 This is a schematic diagram of the exploded structure of the tightening device. Figure 2 This is an isometric schematic diagram of the cylindrical housing 1 included in the tightening device. Figure 3 This is an isometric schematic diagram of the first drive shaft 2 included in the tightening device. Figure 4 This is an isometric schematic diagram of the planetary gear set 3 included in the tightening device. Figure 5 This is an isometric schematic diagram of the second drive shaft 4 included in the tightening device. Figure 6 This is an isometric schematic diagram of the first assembly sleeve 5 included in the tightening device. Figure 7 This is an isometric schematic diagram of the second mounting sleeve 6 included in the tightening device; the tightening device includes a cylindrical housing 1, a first drive shaft 2, a planetary gear set 3, a second drive shaft 4, a first mounting sleeve 5, and a second mounting sleeve 6; the planetary gear set 3 is disposed inside the cylindrical housing 1, and at least part of the second drive shaft 4 is disposed inside the cylindrical housing 1; the planetary gear set 3 is connected to the second drive shaft 4, and the planetary gear set 3 is used to switch the rotation direction of the second drive shaft 4; the first mounting sleeve 5 is disposed on the second drive shaft 4; the first mounting sleeve 5 is used to engage a nut; the second drive shaft 4 includes a through cavity 41, the diameter of which is larger than the outer diameter of the second mounting sleeve 6; the first drive shaft 2 passes through the cylindrical housing 1 and is connected to the planetary gear set 3, and the first drive shaft also passes through the planetary gear set 3 and is connected to the first mounting sleeve 5 in the through cavity 41; the first drive shaft 2 is used to receive external drive input; the inner diameter of the first mounting sleeve 5 is larger than the outer diameter of the second mounting sleeve 6, and the first mounting sleeve 5 is used to engage a bolt.

[0024] Reference Figure 2 The cylindrical housing 1 is a cylindrical structure with a chamber for accommodating other components. One end of the chamber is sealed, while the other end is open. The sealed end is referred to as the end face of the cylindrical housing 1. To facilitate the assembly of the tightening device, this end face can be machined into a removable end cap. When using the tightening device, the cylindrical housing 1 remains fixed. Therefore, the outer surface of the cylindrical housing 1 can be machined into a textured surface that is easy for a person to grip, or other surfaces that are easy to be clamped by a fixing fixture.

[0025] Reference Figure 3The first drive shaft 2 can be a cylindrical shaft. The end of the first drive shaft 2 facing away from the cylindrical housing 1 is the fourth connecting part 21. The fourth connecting part 21 is used to receive external drive input (the external drive input can come from the output shaft of a drive component such as a motor, used to provide torque to the tightening device). The fourth connecting part 21 can be machined as an internal spline, external spline, hexagonal shaft or hexagonal hole to receive the torque of the external drive input. The other end of the first drive shaft 2 extends into the cylindrical housing 1 and is connected to the second mounting sleeve 6 of the tightening device. The end of the first drive shaft 2 connected to the second mounting sleeve is the fifth connecting part 22. Similarly, the fifth connecting part 22 can be machined as an internal spline, external spline, hexagonal shaft or hexagonal hole to transmit torque to the second mounting sleeve 6, and finally transmit the torque to the bolt fitted by the second mounting sleeve 6.

[0026] It should be noted that hexagonal holes or hexagonal shafts are only one optional combination of holes and shafts for transmitting torque in the field of vehicle assembly. They can also be processed into holes or shafts with other radial cross-sectional shapes (such as square holes or square shafts). This embodiment of the invention does not impose any limitations on this.

[0027] A through hole 12 is provided on the end face of the cylindrical shell 1 to allow the first drive shaft 2 to pass through. The diameter of the through hole 12 is larger than the diameter of the first drive shaft 2. The through hole 12 is preferably located at the geometric center of the end face of the cylindrical shell 1.

[0028] Reference Figure 4 The planetary gear set 3 is disposed inside the cylindrical housing 1, with its outer edge maintaining a certain distance from the inner wall of the cylindrical housing 1. The planetary gear set 3 is connected to the first drive shaft 2 to receive torque from the first drive shaft 2. The planetary gear set 3 is also connected to the second drive shaft 4 to transmit torque to the second drive shaft 4, and finally to the nut fitted by the first mounting sleeve. The planetary gear set 3 is a gear system that can change the output rotation direction in the same plane. Therefore, when the first drive shaft 2 receives external drive input, the rotation direction of the second drive shaft 4 and the first mounting sleeve 5 is different from the rotation direction of the second mounting sleeve 6. As a result, the bolt and nut can rotate relative to each other and receive torques in different directions, thereby achieving efficient tightening between the bolt and nut.

[0029] Reference Figure 5One end of the second drive shaft 4 is fixedly connected to the planetary gear set 3 to receive the torque changed by the planetary gear set 3, and the other end of the second drive shaft 4 can be used to connect the first assembly sleeve 5. The second drive shaft 4 has a hollow cavity 41 inside, which can accommodate the part of the first drive shaft 2 that passes through the planetary gear set 3. The diameter of the hollow cavity 41 (if the cross-section of the hollow cavity 41 is a polygon, then the diameter is the diameter of the circumcircle of the polygon) is larger than the outer diameter of the second assembly sleeve 6, so that the first drive shaft 2 can be connected to the second assembly sleeve 6 in the hollow cavity 41, and the rotation of the second drive shaft 4 and the second assembly sleeve 6 will not interfere with each other.

[0030] Reference Figure 7 One end of the second assembly sleeve 6 is a seventh connecting part 61, which is used to connect with the fourth connecting part 21 of the second drive shaft 4. The seventh connecting part 61 can be machined into an external spline, internal spline, hexagonal hole or hexagonal shaft that mates with the fourth connecting part 21. The other end of the second assembly sleeve 6 is a second sleeve part 62, which is used to sleeve bolts (generally the tail end of the bolt stud).

[0031] Reference Figure 6 The first mounting sleeve 5 has a hollow structure, with the diameter of its internal hollow structure being larger than the outer diameter of the second mounting sleeve 6. This ensures that after the second mounting sleeve 6 passes through the central cavity of the second drive shaft 4, it can extend into the first mounting sleeve 5, thereby enabling the simultaneous fitting of bolts and nuts without interference. One end of the first mounting sleeve 5 is a sixth connecting part 51, which can be machined into a hollow hexagonal shaft or a hollow external spline to transmit torque while ensuring strength. The other end of the first mounting sleeve 5 is a first fitting part 52, used for fitting nuts.

[0032] In summary, the tightening device provided by this invention operates the nut and bolt from the same side of the connected workpieces through a first mounting sleeve and a second mounting sleeve, respectively. The inner diameter of the first mounting sleeve is larger than the outer diameter of the second mounting sleeve, allowing the second mounting sleeve to extend from the hollow cavity and pass through the first mounting sleeve. On the one hand, this arrangement reduces the working space of the tightening device, thus adapting to assembly operations in confined spaces. On the other hand, it also avoids interference between the first and second mounting sleeves when operating the bolt and nut. The second mounting sleeve is directly connected to the first drive shaft, giving it the same rotational speed as the first drive shaft. The first mounting sleeve is indirectly connected to the first drive shaft via a planetary gear set and the second drive shaft. Through the planetary gear set, the tightening device can change the rotation direction of the first mounting sleeve, thereby making the rotation directions of the first and second mounting sleeves different. As a result, the nut and bolt can simultaneously receive torques in different directions, thus efficiently tightening the nut and bolt.

[0033] Optional, refer to Figure 4The planetary gear set 3 includes a sun gear 31, planet gears 32, a planet carrier 33, and an internal gear ring 34; the sun gear 31 meshes with at least two planet gears 32, the planet gears 32 also mesh with the internal gear ring 34, and the internal gear ring 34 is connected to the second drive shaft 4; the planet carrier 33 includes a first connecting part 331, a second connecting part 332, and a movable block 333; the first connecting part 331 is connected to the planet gears 32, and the second connecting part 332 is used to connect the first connecting part 331; the movable block 333 is used to connect the second connecting part 332 and the planet gears 32, or to connect the second connecting part 332 and the cylindrical housing 1.

[0034] The planetary gear set 3 includes a sun gear 31, several planet gears 32, a planet carrier 33, and an internal gear ring 34. The sun gear 31 is connected to the first drive shaft 2 to receive torque from the first drive shaft 2. Around the sun gear 31, at least two planet gears 32 are arranged. These planet gears 32 can have the same diameter and all mesh with the sun gear 31. An internal gear ring 34 is wrapped around the outside of the planet gears 32 and meshes with the planet gears 32. The internal gear ring 34 is the outer edge of the planetary gear set 3 and is connected to the second drive shaft 4. These planet gears 32 are also connected and supported by the planet carrier 33. The planet carrier 33 includes a first connecting part 331, a second connecting part 332, and a movable block 333. The first connecting part 331 connects to the body of the planet gears 32, and the second connecting part 332 connects to the adjacent first connecting part 331. Thus, when the sun gear 31 rotates, the planet gears 32 can both rotate on their own axis due to meshing with the sun gear 31 and revolve around the sun gear 31.

[0035] The movable block 333 can change state to connect the second connecting part 332 and the planetary gear 32, or connect the second connecting part 332 and the cylindrical housing 1.

[0036] When the movable block 333 connects the second connecting part 332 and the planetary gear 32, the planetary gear 32 cannot rotate on its own. When the sun gear 31 rotates, the planetary gear 32 can only follow the sun gear 31 to revolve. According to the meshing relationship between the sun gear 31, the planetary gear 32 and the internal gear ring 34, the internal gear ring 34 and the sun gear 31 are directly connected at this time. The rotational speed of the internal gear ring 34 is the same as the rotational direction and speed of the sun gear 31. Therefore, the rotational speed output to the second drive shaft 4, the first mounting sleeve 5 and the nut is the same as the rotational speed output to the second mounting sleeve 6 and the bolt, that is, to keep the nut and the bolt rotating together and to avoid the torque of the nut from exceeding the torque threshold during assembly.

[0037] When the movable block 333 connects the second connecting part 332 and the cylindrical shell 1, the planet carrier 33 is fixed relative to the cylindrical shell 1, and the planet gear 32 can only rotate on its own axis instead of revolving around the sun gear 31. According to the meshing relationship between the sun gear 31, the planet gear 32 and the internal gear ring 34, the rotation directions of the internal gear ring 34 and the sun gear 31 are opposite at this time. The rotation speed of the internal gear ring 34 is opposite to the rotation direction of the sun gear 31. Therefore, the rotation speed output to the second drive shaft 4, the first mounting sleeve 5 and the nut is opposite to the rotation speed output to the second mounting sleeve 6 and the bolt. That is, the nut and the bolt reverse direction. The nut and the bolt receive torque in different directions at the same time, which can quickly achieve the fastening between the nut and the bolt.

[0038] Optional, in conjunction with reference Figure 2 and Figure 4 The cylindrical housing 1 has a first fixing hole 11 on its end face, and the planetary gear 32 has a second fixing hole 321 on its end face. The movable block 333 is disposed in the second connecting part 332. The movable block 333 has a switchable first state and a second state. In the first state, the movable block 333 extends into the first fixing hole 11 to connect the cylindrical housing 1 and the second connecting part 332. In the second state, the movable block 333 extends into the second fixing hole 321 to connect the second connecting part 332 and the planetary gear 32.

[0039] The movable block 333 of the planetary gear set 3 has a switchable first state and a second state. The movable block 333 can switch between different states by extending into different fixing holes. The movable block 333 is disposed on the second connecting part 332 and can move relative to the second connecting part 332. At least one first fixing hole 11 is provided on the end face of the cylindrical housing 1, and at least one second fixing hole 321 is provided on the planetary gear 32 (at least one second fixing hole 321 can be provided on each planetary gear 32). When the projection of the first fixing hole 11 and the position of the movable block 333 coincides, the movable block 333 can be moved so that one end of the movable block 333 extends into the first fixing hole. When the first fixing hole 11 is in the first state, the movable block 333 will connect the cylindrical shell 1 and the second connecting part 332, restricting the relative rotation between the planetary carrier 33 and the cylindrical shell 1. When the projection of the second fixing hole 321 and the position of the movable block 333 are coincident, the movable block 333 can be moved so that the other end of the movable block 333 extends into the second fixing hole 321, entering the second state. At this time, the movable block 333 will connect the planetary gear 32 and the second connecting part 332, restricting the rotation of the planetary gear 32. The first fixing hole 11 and the second fixing hole 321 can coincide during the revolution of the planetary gear 32. At this time, the movable block 333 can switch between the first state and the second state.

[0040] Optionally, the tightening device also includes a sensor (both shown in the figure) and a controller (both shown in the figure); the sensor is used to obtain the real-time torque of the first assembly sleeve 5, and the controller is used to set the movable block 333 to the second state when the real-time torque is greater than or equal to a preset torque threshold, and to set the movable block 333 to the first state when the real-time torque is less than the preset torque threshold.

[0041] The tightening device can be equipped with a sensor and a controller. The sensor is used to acquire the real-time torque of the first assembly sleeve 5, i.e., the torque output to the nut. When the real-time torque is greater than or equal to a preset torque threshold, the controller moves the movable block 333 into the second fixing hole 321, so that the movable block 333 enters the second state. When the real-time torque is less than the preset torque threshold, the controller moves the movable block 333 into the first fixing hole 11, so that the movable block 333 enters the first state. The significance of this configuration is that, in the vehicle assembly scenario, the nut has a maximum withstand torque, so to ensure that the nut will not be damaged by excessive torque... In the case of excessive torque, during the tightening process, when the torque received by the nut reaches the preset torque threshold, the movable block 333 enters the second state. At this time, the planetary gear set 3 acts as a direct connection, making the rotation direction and speed of the first mounting sleeve 5 and the second mounting sleeve 6 consistent, thereby realizing that the bolt and nut rotate together, preventing the nut and bolt from getting closer, preventing the torque input to the nut from increasing further, and reducing the risk of the nut being damaged due to excessive torque. Here, the preset torque threshold can be slightly less than the maximum bearable torque of the nut, so that the movable block 333 can extend into the second fixing hole 321 before the torque increases to the maximum bearable torque of the nut.

[0042] When the real-time torque is less than the preset torque threshold, it indicates that the optimal tightening effect has not been achieved. At this time, the controller can move the movable block 333 to enter the first state. After the movable block 333 enters the first state, the planetary carrier 33 is locked and cannot rotate relative to the cylindrical housing 1. The internal gear ring 34 is reversed relative to the sun gear 31, so that the rotation direction of the first mounting sleeve 5 and the second mounting sleeve 6 is opposite, so that the bolt and nut continue to move closer to ensure the tightening effect.

[0043] Furthermore, in order to smoothly achieve the withdrawal of the first mounting sleeve 5 and the second mounting sleeve 6, the controller can also be configured to issue a target signal after the real-time torque is maintained at a preset torque threshold for a preset duration. The target signal can be a modulated electrical signal to shut off the external drive input received by the first drive shaft 2, or an audible and visual signal to prompt the operator to manually shut off the external drive input received by the first drive shaft 2.

[0044] Optionally, the first drive shaft 2 is coaxially arranged with the sun gear 31 and is fixedly connected to the sun gear 31; the first drive shaft 2 passes through the sun gear 31 along the axial direction of the sun gear 31 and is connected to the second assembly sleeve 6 in the hollow cavity 41; the first connecting part 331 is coaxially arranged with the planet gear 32 respectively, and the first connecting part 331 is rotatably connected to the planet gear 32; the second connecting part 332 connects the first connecting part 331 on two adjacent planet gears 32.

[0045] The first drive shaft 2 passes through the center of the sun gear 31 and is fixedly connected to the sun gear 31. The first drive shaft 2 can be fixedly connected to the sun gear 31 through a shaft hole. After the first drive shaft 2 passes through the sun gear 31, its end can be connected to the second assembly sleeve 6 in the hollow cavity 41 of the second drive shaft 4, so that the sun gear 31 and the second assembly sleeve are coaxially arranged. After receiving external drive input, the first drive shaft 2 can directly drive the second assembly sleeve 6 or indirectly drive the first assembly sleeve 5 through the planetary gear set 3.

[0046] To ensure the load-bearing capacity of the sun gear 31, the sun gear 31 can be manufactured using alloy steel (e.g., 20CrMnTi) and subjected to carburizing and quenching treatment.

[0047] The first connecting part 331 of the planet carrier 33 is rotatably connected to the planet gear 32 on the same axis to ensure that the planet gear 32 can rotate around the first connecting part 331. The second connecting part 332 is used to connect the adjacent first connecting parts 331 so that the relative positions between the multiple planet gears 32 remain fixed.

[0048] Optional, refer to Figure 4 There are three planetary gears 32. The lines connecting the axes of the planetary gears 32 form an equilateral triangle, and the axis of the sun gear 31 is located at the geometric center of the equilateral triangle.

[0049] In one alternative embodiment, there are three planetary gears 32, and the line connecting the axes of the three planetary gears 32 forms an equilateral triangle. The axis of the sun gear 31 is located at the geometric center of the equilateral triangle. That is, the three planetary gears 32 are evenly arranged around the sun gear 31 at 120°. This arrangement can achieve a balance between the cost of the planetary gear set 3 and the load capacity of the planetary gear set 3.

[0050] Optional, refer to Figure 5 The second drive shaft 4 has a countersunk hole 42 on the side near the internal gear ring 34. The countersunk hole 42 is connected to the through cavity 41. The outer diameter of the internal gear ring 34 matches the diameter of the countersunk hole 42. The countersunk hole 42 is used to connect with the internal gear ring 34.

[0051] The second drive shaft 4 can be connected to the internal gear ring 34 in the planetary gear set 3 via a hole-shaft connection. A countersunk hole 42 is provided at one end of the second drive shaft 4 near the internal gear ring 34. The diameter of the countersunk hole 42 matches the outer diameter of the internal gear ring 34, so that the internal gear ring 34 and the countersunk hole 42 are fitted together to achieve a fixed connection, thereby transmitting the torque output by the planetary gear set 3 to the second drive shaft 4. The bottom surface of the countersunk hole 42 is connected to the hollow cavity 41, ensuring that the first drive shaft 2 passing through the planetary gear set 3 can extend into the hollow cavity 41.

[0052] Optional, refer to Figure 8 , Figure 8 The diagram shows an isometric view of the floating joint 7 included in the tightening device. The tightening device also includes the floating joint 7. The first assembly sleeve 5 is disposed at the end of the second drive shaft 4 away from the planetary gear set 3 via the floating joint 7. The floating joint 7 includes multiple elastic elements 71 and a third connecting part 72. One end of the elastic element 71 is connected to the end of the second drive shaft 4 away from the planetary gear set 3, and the other end of the elastic element 71 is connected to the third connecting part 72. The third connecting part 72 is used to connect the first assembly sleeve 5.

[0053] The tightening device can also be equipped with a floating joint 7 to enable the first assembly sleeve 5 to float. The floating joint 7 includes multiple elastic elements 71 and a third connecting part 72. The third connecting part 72 has a hollow structure inside, and the diameter of the hollow structure should be larger than the outer diameter of the second assembly sleeve 6 to ensure that the second assembly sleeve 6 can pass through the third connecting part 72. The shape of the third connecting part 72 matches that of the sixth connecting part 51 of the first assembly sleeve 5. For example, if the sixth connecting part 51 of the first assembly sleeve 5 is machined as an external spline, then the third connecting part 72 should be machined as an internal spline that mates with it. There are multiple elastic elements 71, which can be evenly distributed along the end edge of the third connecting part 72. For example, if the third connecting part 72 is machined as a regular hexagon with a radial cross section (i.e., the third connecting part 72 is machined as a hexagonal shaft), then there can be six elastic elements 71, which are respectively set on the six vertices of the end face of the third connecting part 72.

[0054] The floating joint 7 allows the second assembly sleeve 6 to be fitted onto the nut when the nut is tilted relative to the bolt thread, and to straighten the nut before rotation begins, thus avoiding tilted installation of the nut.

[0055] Optional, in conjunction with reference Figure 5 and Figure 8 The second drive shaft 4 has a mounting seat 43 at one end near the floating joint 7. The mounting seat 43 is connected to the hollow cavity 41. The size and shape of the mounting seat 43 match the third connecting part 72. One end of the elastic member 71 is connected to the bottom surface of the mounting seat 43, and the other end of the elastic member 71 is connected to the third connecting part 72.

[0056] A mounting base 43 can be provided at one end of the second drive shaft 4 near the floating joint 7. The shape and size of the mounting base 43 match the third connecting part 72 to restrict the rotation of the third connecting part 72 relative to the second drive shaft 4 after the floating joint 7 begins to rotate. For example, if the third connecting part 72 is machined as a hexagonal shaft, the mounting base 43 should be a hexagonal hole. The rotation of the third connecting part 72 is restricted by multiple inner surfaces of the mounting base 43 contacting the surface of the third connecting part 72. The mounting base 43 communicates with the hollow cavity 41 to ensure that the second mounting sleeve 6 can extend from the hollow cavity 41. When the mounting base 43 is installed, the mounting base 43 and the through cavity 41 form a stepped structure. The end of the elastic element 71 that is away from the third connecting part 72 can be set on the stepped structure, that is, on the bottom surface of the mounting base 43, so that the floating joint 7 can float and move only along the axial direction. When the tightening device is working, the elastic element 71 is pressed by the bottom surface of the mounting base 43 and the third connecting part 72, so that part of the third connecting part 72 is embedded in the mounting base 43, preventing the third connecting part 72 from rotating relative to the second drive shaft 4.

[0057] Optional, in conjunction with reference Figure 2 and Figure 5 The second drive shaft 4 includes a first part 44 and a second part 45 along the axial direction; the inner wall of the cylindrical housing 1 is provided with a protruding structure 13 along the circumferential direction; the diameter of the first part 44 is larger than the diameter of the second part 45, the first part 44 is located in the cylindrical housing 1 near one end of the planetary gear set 3, and the first part 44 abuts against the protruding structure 13.

[0058] The second drive shaft 4 can slide in contact with the inner wall of the cylindrical shell 1 and can rotate relative to the inner wall of the cylindrical shell 1. Lubricant can be filled in the gap between the second drive shaft 4 and the inner wall of the cylindrical shell 1 to ensure the transmission effect of the second drive shaft 4. The second drive shaft 4 can be divided into a first part 44 with a larger diameter and a second part 45 with a smaller diameter along the axial direction. The first part 44 is responsible for contacting the inner wall of the cylindrical shell 1. Since the diameters of the first part 44 and the second part 45 are different, the second drive shaft 4 is a stepped shaft. The inner wall of the cylindrical shell 1 has a circumferential protrusion structure 13. When installing the second drive shaft 4, the first part 44 of the stepped second drive shaft 4 will abut against the protrusion structure 13. With the cooperation of the end face of the cylindrical shell 1, the second drive shaft 4 can be constrained in the axial direction. Similarly, lubricant can be filled in the gap between the protrusion structure 13 and the second drive shaft 4 to reduce the rotational friction of the second drive shaft 4. The second part 45 can extend out of the cylindrical shell 1 and connect to the floating joint 7 or the first assembly sleeve 5, or it can connect to the floating joint 7 or the first assembly sleeve 5 inside the cavity of the cylindrical shell 1.

[0059] In summary, the tightening device provided by this invention operates the nut and bolt from the same side of the connected workpieces through a first mounting sleeve and a second mounting sleeve, respectively. The inner diameter of the first mounting sleeve is larger than the outer diameter of the second mounting sleeve, allowing the second mounting sleeve to extend from the hollow cavity and pass through the first mounting sleeve. On the one hand, this arrangement reduces the working space of the tightening device, thus adapting to assembly operations in confined spaces. On the other hand, it also avoids interference between the first and second mounting sleeves when operating the bolt and nut. The second mounting sleeve is directly connected to the first drive shaft, giving it the same rotational speed as the first drive shaft. The first mounting sleeve is indirectly connected to the first drive shaft via a planetary gear set and the second drive shaft. Through the planetary gear set, the tightening device can change the rotation direction of the first mounting sleeve, thereby making the rotation directions of the first and second mounting sleeves different. As a result, the nut and bolt can simultaneously receive torques in different directions, thus efficiently tightening the nut and bolt.

[0060] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tightening device, characterized in that The tightening device comprises a cylindrical shell, a first transmission shaft, a planetary gear set, a second transmission shaft, a first assembly sleeve and a second assembly sleeve; The planetary gear set is arranged in the cylindrical shell, and at least part of the second transmission shaft is arranged in the cylindrical shell; the planetary gear set is connected with the second transmission shaft, and the planetary gear set is used for switching the rotation direction of the second transmission shaft; the first assembly sleeve is arranged on the second transmission shaft; and the first assembly sleeve is used for sleeving a nut; The second transmission shaft comprises a through cavity, and the diameter of the through cavity is greater than the outer diameter of the second assembly sleeve; The first transmission shaft is connected with the planetary gear set through the cylindrical shell, and the first transmission shaft also passes through the planetary gear set and is connected with the first assembly sleeve in the through cavity; the first transmission shaft is used for receiving an external driving input; the inner diameter of the first assembly sleeve is greater than the outer diameter of the second assembly sleeve, and the second assembly sleeve is used for sleeving a bolt.

2. The tightening device according to claim 1, characterized in that The planetary gear set comprises a sun gear, a planet gear, a planet carrier and an inner ring gear; The sun gear is connected with the first transmission shaft, the sun gear is engaged with at least two planet gears, the planet gears are further engaged with the inner ring gear, and the inner ring gear is connected with the second transmission shaft; The planet carrier comprises a first connecting part, a second connecting part and a movable block; the first connecting part is connected with the planet gear, the second connecting part is used for connecting the first connecting part; and the movable block is used for connecting the second connecting part and the planet gear, or connecting the second connecting part and the cylindrical shell.

3. The tightening device according to claim 2, characterized in that An end surface of the cylindrical shell is provided with a first fixing hole, an end surface of the planet gear is provided with a second fixing hole, and the movable block is arranged on the second connecting part; The movable block has switchable first and second states; in the first state, the movable block extends into the first fixing hole to connect the cylindrical shell and the second connecting part; and in the second state, the movable block extends into the second fixing hole to connect the second connecting part and the planet gear.

4. The tightening device according to claim 3, characterized in that The tightening device further comprises a sensor and a controller; The sensor is used for acquiring a real-time torque of the first assembly sleeve, the controller is used for setting the movable block to the second state when the real-time torque is greater than or equal to a preset torque threshold, and setting the movable block to the first state when the real-time torque is less than the preset torque threshold.

5. The tightening device according to claim 2, characterized in that The first transmission shaft is coaxially arranged with the sun gear, and the first transmission shaft is fixedly connected with the sun gear; the first transmission shaft passes through the sun gear along the axial direction of the sun gear and is connected with the second assembly sleeve in the through cavity; The first connecting parts are coaxially arranged with the planet gears respectively, and the first connecting parts are rotationally connected with the planet gears; and the second connecting part connects the first connecting parts on two adjacent planet gears.

6. The tightening device according to claim 2, characterized in that There are three planet gears, the axial center lines of the planet gears form an equilateral triangle, and the axial center of the sun gear is arranged at the geometric center of the equilateral triangle.

7. The tightening device according to claim 2, characterized in that The second transmission shaft is provided with a counterbore close to one side of the inner ring gear, the counterbore is communicated with the through cavity, the outer diameter of the inner ring gear matches the diameter of the counterbore, and the counterbore is used for connecting with the inner ring gear.

8. The tightening device of claim 1, wherein The tightening device further comprises a floating joint; The first assembly sleeve is arranged at one end of the second transmission shaft away from the planetary gear set through the floating joint; The floating joint comprises a plurality of elastic members and a third connecting part; One end of the elastic member is connected to one end of the second transmission shaft away from the planetary gear set, and the other end of the elastic member is connected to the third connecting part; and the third connecting part is used for connecting the first assembly sleeve.

9. The tightening device according to claim 8, characterized in that The second transmission shaft is provided with a mounting seat close to one end of the floating joint, the mounting seat is communicated with the through cavity, the size and shape of the mounting seat match the third connecting part, one end of the elastic member is connected to the bottom surface of the mounting seat, and the other end of the elastic member is connected to the third connecting part.

10. The tightening device of claim 1, wherein The second transmission shaft comprises a first part and a second part in the axial direction; and the inner wall of the cylindrical shell is provided with a protruding structure in the circumferential direction; The diameter of the first part is greater than that of the second part, the first part is arranged at one end of the cylindrical shell close to the planetary gear set, and the first part abuts against the protruding structure.

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