A cross axle type robot joint

Abstract

The utility model provides a kind of cross axle type robot joint, it is related to robot joint technical field, including installation base, still including connecting rod fixedly arranged in the one side of installation base, U-shaped swing arm is arranged in the outside of connecting rod, driving part is arranged in the one side of U-shaped swing arm, the driving part is used to drive U-shaped swing arm to rotate, sliding seat is arranged in the bottom end outside of U-shaped swing arm, the inside of sliding seat is provided with limit part, connecting piece is arranged in the one side of sliding seat, this cross axle type parallel robot joint volume is compact, adapts humanoid robot small space joint installation demand, and angle adjustment is flexible and accurate, motion performance is excellent, and it adopts the compact linkage structure of cross axle body and arc swing arm, U-shaped swing arm, realizes multidimensional angle adjustment in limited space.

Description

Technical Field

[0001] This utility model relates to the field of robot joint technology, and in particular to a cross-axis robot joint. Background Technology

[0002] Robot joints can be classified into single-degree-of-freedom (DOF), two-degree-of-freedom (DDF), and three-degree-of-freedom (DDF) joints based on the number of degrees of freedom. Three-degree-of-freedom joints are commonly used in critical areas such as the neck, shoulder, wrist, ankle, and waist. The structural forms of three-degree-of-freedom joints generally include series, parallel, and series-parallel composite structures. In practical applications, to ensure the accuracy and convenience of kinematic solutions, it is often required that the three rotational axes intersect at a single point. The most widely used solution in this case is a combination of "single rotational DDF series connection + cross-shaped two-degree-of-freedom parallel connection."

[0003] A search revealed that Chinese patent CN119610202A places the motor at the intersection point, which simplifies the structure but results in a bulky structure in the intersection area, affecting the adaptability of the installation space. Another approach, as shown in Chinese patent CN223199056U, uses a spatial linkage structure to externally mount the motor. While this reduces the volume at the intersection point, the linkage has a large range of motion, still failing to solve the problem of an overall bulky structure. Neither of these solutions can meet the stringent requirements of miniaturized equipment for joint space.

[0004] The aforementioned robot joints suffer from large size and bulky structure, resulting in poor adaptability, insufficient motion flexibility, and limited application scenarios. The excessive size and bulky structure make it difficult to meet the requirements of humanoid robots and other devices with strict space constraints for joint installation, hindering flexible integration into small installation locations and limiting the compact design of the overall robot structure. The bulky structure also leads to a dispersed layout of transmission components, increasing inertial resistance during joint movement, reducing the accuracy and response speed of angle adjustments, and affecting the multi-dimensional motion flexibility of the joints, making it difficult to achieve complex posture adjustments. Furthermore, the large size increases the overall weight of the robot, exacerbating energy consumption. The numerous parts and complex assembly of the bulky structure not only increase manufacturing costs but also increase the difficulty and cost of later maintenance, making it unsuitable for the high-precision, miniaturized, and highly flexible requirements of modern robot applications. Utility Model Content

[0005] The purpose of this invention is to provide a cross-axis robot joint that solves the problems of large size and bulky structure of the aforementioned robot joints, resulting in poor adaptability, insufficient motion flexibility, and limited application scenarios. Excessive size and bulky structure make it difficult to meet the requirements of humanoid robots and other devices with strict requirements for joint installation space, hindering flexible integration into small installation locations and limiting the compact design of the overall robot structure. The bulky structure also leads to a dispersed layout of transmission components, increasing inertial resistance during joint movement, reducing the accuracy and response speed of angle adjustment, and affecting the multi-dimensional motion flexibility of the joint, making it difficult to achieve complex posture adjustments. Simultaneously, the large size increases the overall weight of the robot, exacerbating energy consumption. Furthermore, the large number of parts and complex assembly of the bulky structure not only increase manufacturing costs but also increase the difficulty and cost of later maintenance, failing to meet the high-precision, miniaturized, and highly flexible requirements of modern robot applications.

[0006] To achieve the above objectives, this utility model adopts the following technical solution: a cross-axis robot joint, including a mounting base, and further comprising: A connecting rod is fixedly mounted on one side of the mounting base; A U-shaped swing arm is provided on the outside of the connecting rod; A driving component is disposed on one side of the U-shaped swing arm, and the driving component is used to drive the U-shaped swing arm to rotate; A sliding seat is provided on the outer side of the bottom end of the U-shaped swing arm, and a limiting member is provided on the inner side of the sliding seat; A connector is provided on one side of the sliding seat.

[0007] In a preferred embodiment, a connecting seat is disposed on one side of the U-shaped swing arm; A limiting groove is formed on the inner side of the end of the U-shaped swing arm, and the connecting rod is disposed on the inner side of the limiting groove; An arc-shaped swing arm is fixedly mounted on the outer side of the end of the connecting rod away from the mounting base; A cross block is disposed on the inner side of the arc-shaped swing arm; A cross bar is fixedly installed on the outer sides of both ends of the cross block, and the cross block is rotatably connected to the inner side of the arc-shaped swing arm through the cross bar; The cross shaft is fixedly installed on the outer sides of both ends of the cross block; A fixing plate is fixedly mounted on the upper surface of the connecting seat, and the cross shaft is rotatably mounted on the inner side of the end of the fixing plate.

[0008] In a preferred embodiment, the connecting rod can rotate inside the limiting groove, the U-shaped swing arm has a U-shaped structure, and the arc-shaped swing arm can rotate inside the U-shaped swing arm.

[0009] In one preferred embodiment, a first motor is mounted on the lower surface of the sliding seat; The first pulley is fixedly mounted on the outside of the main shaft of the first motor; The second pulley is rotatably mounted on one side of the fixed plate. The cross shaft passes through the outer end of the fixed plate and is connected to the inner middle of the arc-shaped swing arm. The first pulley and the second pulley are connected by a belt.

[0010] In one preferred embodiment, the first connecting plate is fixedly disposed on one side of the first motor; The second motor is installed on the inner side of the end of the first connecting plate; The second connecting plate is fixedly installed on one side of the sliding seat, and the inner side of the end of the second connecting plate is sleeved on the outer side of the top of the second motor. The first bevel gear is fixedly mounted on the outside of the main shaft of the second motor; The second bevel gear is fixedly disposed on the outer side of the end of the U-shaped swing arm, and the first bevel gear is meshed with the second bevel gear.

[0011] In a preferred embodiment, the snap-fit ​​block is movably disposed on the inner side of the bottom end of the connector, and the outer side of the end of the snap-fit ​​block is provided with an inclined structure. The insertion rod is movably disposed inside the connector. A snap-fit ​​ball is fixedly disposed on the outer side of the middle part of the plug rod, and the outer side of the snap-fit ​​ball is in contact with the inner side of the middle part of the snap-fit ​​block; A spring is fixedly disposed on the outer side of the end of the insertion rod, and the outer side of the end of the spring away from the insertion rod is fixedly connected to the inner side of the bottom end of the connecting seat.

[0012] In a preferred embodiment, a button is fixedly disposed on the outer side of the end of the plug rod away from the spring, and one side of the button is made of silicone material.

[0013] In a preferred embodiment, a friction strip is fixedly provided on the outer side of the end of the snap-fit ​​block, and the snap-fit ​​block contacts the inner side of the trapezoidal through groove of the sliding seat through the friction strip.

[0014] Compared with the prior art, the advantages and positive effects of this utility model are as follows: This cross-axis parallel robot joint is compact, suitable for the space-constrained joint installation requirements of humanoid robots, and offers flexible and precise angle adjustment with excellent motion performance. It employs a compact linkage structure of the cross axis, arc-shaped swing arms, and U-shaped swing arms, achieving multi-dimensional angle adjustment within a limited space without occupying excessive installation space. A second motor drives the meshing of the first and second bevel gears, rotating the U-shaped swing arms, connecting rods, and mounting base. The guiding effect of the limiting groove ensures precise and stable rotation angle adjustment. Simultaneously, the first motor drives the first and second pulleys, which in turn drive the cross axis, cross block, and cross rod to rotate the arc-shaped swing arms, achieving secondary angle adjustment of the connecting rods. This dual-adjustment structure meets the complex motion requirements of humanoid robot joints. Attached Figure Description

[0015] Figure 1 A front view schematic diagram of a cross-axis robot joint provided by this utility model; Figure 2 A schematic diagram of the structure of the first motor and the first pulley in a cross-axis robot joint provided by this utility model; Figure 3 A cross-sectional view of the first motor in a cross-axis robot joint provided by this utility model; Figure 4 A schematic diagram of the structure of the insert rod and friction strip in the joint of a cross-axis robot provided by this utility model; Figure 5 This utility model provides a structural schematic diagram of a cross-axis robot joint that mounts a base and a connecting rod.

[0016] Legend: 1. Mounting base; 101. Connecting rod; 2. U-shaped swing arm; 201. Connecting seat; 202. Limiting groove; 203. Arc-shaped swing arm; 204. Cross shaft; 205. Cross block; 206. Cross rod; 207. Fixing plate; 3. Sliding seat; 301. First motor; 302. First pulley; 303. Second pulley; 304. First connecting plate; 305. Second motor; 306. Second connecting plate; 307. First bevel gear; 308. Second bevel gear; 4. Snap-fit ​​block; 401. Insert rod; 402. Snap-fit ​​ball; 403. Spring; 404. Button; 405. Friction strip. Detailed Implementation

[0017] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0018] Example 1: Please see Figure 1 - Figure 5 This embodiment provides a more compact cross-axis robot joint, the specific idea of ​​which is as follows: A cross-axis robot joint includes a mounting base 1, and the cross-axis robot joint also includes a U-shaped swing arm 2 and a drive component.

[0019] One side of the mounting base 1 is fixedly connected to a connecting rod 101, which serves as a connecting support component for the U-shaped swing arm 2 and provides a stable axial foundation for the rotational movement of the U-shaped swing arm 2. The U-shaped swing arm 2 is connected to the outside of the connecting rod 101. The U-shaped structure design of the U-shaped swing arm 2 enables the connecting rod 101 to adapt to multi-directional swinging and can rotate around the connecting rod 101 at multiple angles.

[0020] A drive unit is connected to one side of the U-shaped swing arm 2. As the power core of the U-shaped swing arm 2, the drive unit can stably output rotational power to drive the U-shaped swing arm 2 to rotate, and can realize the angle positioning and dynamic adjustment of the U-shaped swing arm 2.

[0021] As examples, in this embodiment, the driving element includes a connecting seat 201 and a limiting groove 202.

[0022] The U-shaped swing arm 2 has a connecting seat 201 connected to one side, which serves as the mounting and bearing structure for the cross shaft 204 and provides stable support for the secondary rotation of the joint. A limiting groove 202 is opened on the inner side of the end of the U-shaped swing arm 2, and the connecting rod 101 is connected to the inner side of the limiting groove 202. The contour of the limiting groove 202 is adapted to the outer side of the connecting rod 101, which can both guide the rotation of the connecting rod 101 and limit its range of motion to avoid excessive rotation that could cause interference between components.

[0023] Meanwhile, an arc-shaped swing arm 203 is fixedly connected to the outer side of the end of the connecting rod 101 away from the mounting base 1. The arc-shaped structure of the arc-shaped swing arm 203 matches the U-shaped structure of the U-shaped swing arm 2, allowing it to rotate flexibly inside the U-shaped swing arm 2. The connecting rod 101 can also rotate synchronously inside the limiting groove 202. This dual rotation design significantly improves the freedom of movement of the joint.

[0024] In addition, a cross block 205 is connected to the inner side of the arc-shaped swing arm 203, and a cross rod 206 is fixedly connected to the outer sides of both ends of the cross block 205. The cross block 205 is rotatably connected to the inner side of the arc-shaped swing arm 203 through the cross rod 206. The cross rod 206 provides axial support for the rotation of the cross block 205 to ensure smooth rotation. A cross shaft 204 is also fixedly connected to the outer sides of both ends of the cross block 205. A fixing plate 207 is fixedly connected to the upper surface of the connecting seat 201. The cross shaft 204 is rotatably connected to the inner side of the end of the fixing plate 207. Through the cooperation of the cross shaft 204 and the fixing plate 207, the joint can rotate in the vertical direction.

[0025] It is worth noting that this multi-component, interconnected cross-axis structure enables the robot joints to achieve combined horizontal and vertical movements, meeting the posture adjustment requirements in complex work scenarios. At the same time, the high-precision matching design of each rotating connection ensures the accuracy and stability of the joint movement, improving the reliability of the robot's operation.

[0026] Example 2: Please see Figure 1 - Figure 5 This embodiment provides a cross-axis robot joint that is easy to maintain and disassemble. The specific idea is as follows: A cross-axis robot joint includes a mounting base 1, and the cross-axis robot joint also includes a sliding seat 3 and a connector.

[0027] Among them, a sliding seat 3 is provided on the outer side of the bottom end of the U-shaped swing arm 2. The sliding seat 3 can slide and adjust along the U-shaped swing arm 2, and can flexibly adjust the installation position. A connector is provided on one side of the sliding seat 3. The connector serves as the connection hub between the sliding seat 3 and other components, enabling the sliding seat 3 to be quickly connected and fixed with adjacent structures.

[0028] As examples, in this embodiment, the connector includes a first motor 301 and a first pulley 302.

[0029] The lower surface of the sliding seat 3 is equipped with a first motor 301. The outer side of the main shaft of the first motor 301 is fixedly connected to a first pulley 302. A second pulley 303 is rotatably connected to one side of the fixed plate 207. The cross shaft 204 passes through the outer end of the fixed plate 207 and is connected to the inner side of the middle part of the arc-shaped swing arm 203. The first pulley 302 and the second pulley 303 are connected by a belt. With the flexible connection characteristics of belt drive, the power can be smoothly transmitted, and at the same time, it has a certain buffering and shock absorption effect, ensuring the stability and accuracy of the cross shaft 204 driving the arc-shaped swing arm 203 to rotate.

[0030] Meanwhile, a first connecting plate 304 is fixedly connected to one side of the first motor 301, and a second motor 305 is installed on the inner side of the end of the first connecting plate 304. A second connecting plate 306 is fixedly connected to one side of the sliding seat 3, and the inner side of the end of the second connecting plate 306 is sleeved on the outer side of the top of the second motor 305. The connecting plate structure forms a stable support for the second motor 305, preventing the motor from shaking during operation and ensuring the stability of power output.

[0031] In addition, a first bevel gear 307 is fixedly connected to the outer side of the main shaft of the second motor 305, and a second bevel gear 308 is fixedly connected to the outer side of the end of the U-shaped swing arm 2. The first bevel gear 307 and the second bevel gear 308 are meshed and connected. The meshing transmission of the bevel gears can realize multi-angle conversion of the power direction, drive the U-shaped swing arm 2 to rotate, meet the multi-directional power drive requirements of the robot joint, and the high-precision characteristics of the meshing transmission can also ensure the angular accuracy of the joint rotation and improve the reliability of the robot operation.

[0032] Example 3: Please see Figure 1 - Figure 5 This embodiment provides a cross-axis robot joint that is easy to maintain and disassemble. The specific idea is as follows: A cross-axis robot joint includes a mounting base 1, and the cross-axis robot joint also includes a locking block 4 and a limiting member.

[0033] Among them, the inner side of the sliding seat 3 is provided with a limiting component; As examples, in this embodiment, the limiting element includes: a plug 401 and a locking ball 402.

[0034] The connecting seat 201 is movably connected to the inner side of the insert rod 401. The outer side of the middle part of the insert rod 401 is fixedly connected to the snap ball 402. The outer side of the snap ball 402 is in contact with the inner side of the middle part of the snap block 4. The snap block 4 can be driven to unfold outward by the squeezing of the snap ball 402, so as to achieve snap engagement with the sliding seat 3.

[0035] Meanwhile, a spring 403 is fixedly connected to the outer side of the end of the insertion rod 401. The outer side of the end of the spring 403 away from the insertion rod 401 is fixedly connected to the inner side of the bottom end of the connecting seat 201. The spring 403 provides elastic restoring force for the insertion rod 401, ensuring that the snap-fit ​​ball 402 always maintains the squeezing state of the snap-fit ​​block 4, thus ensuring the stability of the snap-fit ​​structure.

[0036] In addition, a button 404 is fixedly connected to the outer side of the end of the insertion rod 401 away from the spring 403. One side of the button 404 is made of silicone material. Silicone material has good elasticity and anti-slip properties. It feels comfortable to press and is not easy to slip, making it convenient for operators to control the movement of the insertion rod 401.

[0037] It should be noted that a friction strip 405 is fixedly connected to the outer end of the snap-fit ​​block 4. The snap-fit ​​block 4 contacts the inner side of the trapezoidal through groove of the sliding seat 3 through the friction strip 405. The friction strip 405 is made of a material with a high coefficient of friction, which can increase the friction between the snap-fit ​​block 4 and the sliding seat 3, prevent loosening and slippage after snap-fit, and further improve the stability of the connection structure.

[0038] Working principle: When using the device, the user can activate the second motor 305, which drives the first bevel gear 307 to rotate. Simultaneously, the rotation of the first bevel gear 307 drives the second bevel gear 308, which meshes with it, to rotate. The rotation of the second bevel gear 308, in turn, drives the U-shaped swing arm 2 to rotate. The rotation of the U-shaped swing arm 2, through the limiting groove 202, causes the connecting rod 101 and the mounting base 1 to rotate around the center of the second bevel gear 308, thus adjusting the angle of the connecting rod 101 and the mounting base 1. The user can start the first motor 301, which drives the first pulley 302 to rotate. While the first pulley 302 is rotating, it will drive the second pulley 303 to rotate via a belt. While the second pulley 303 is rotating, it will drive the cross shaft 204 to rotate around the axis of the second pulley 303. While the cross shaft 204 is rotating, it will drive the arc-shaped swing arm 203 to rotate via the cross block 205 and the cross rod 206. Thus, the arc-shaped swing arm 203 can drive the connecting rod 101 to adjust its angle inside the limiting groove 202.

[0039] This cross-axis parallel robot joint is compact, suitable for the space-constrained joint installation requirements of humanoid robots, and offers flexible and precise angle adjustment with excellent motion performance. It employs a compact linkage structure of the cross axis 204, the arc-shaped swing arm 203, and the U-shaped swing arm 2, achieving multi-dimensional angle adjustment within a limited space without occupying excessive installation space. A second motor 305 drives the first bevel gear 307 and the second bevel gear 308 to mesh and rotate the U-shaped swing arm 2, the connecting rod 101, and the mounting base 1. The guiding effect of the limiting groove 202 ensures precise and stable rotation angle adjustment. Simultaneously, the first motor 301 drives the first pulley 302 and the second pulley 303 via belt transmission, linking the cross axis 204, the cross block 205, and the cross rod 206 to rotate the arc-shaped swing arm 203, achieving secondary angle adjustment of the connecting rod 101. This dual-adjustment structure meets the complex motion requirements of humanoid robot joints.

[0040] When the user needs to disassemble the first motor 301, the user can press the plug rod 401 with the button 404 to move it toward the inside of the connecting seat 201, while compressing the spring 403 and storing elastic potential energy. At this time, the locking ball 402 disengages from the inner middle of the locking block 4. The locking ball 402 loses pressure on the locking block 4, and the locking block 4 reduces the pressure on the inner side of the trapezoidal through groove of the sliding seat 3 through the friction strip 405. This allows the sliding seat 3 to slide away from the connecting seat 201, thereby disassembling the sliding seat 3 from the first motor 301.

[0041] This joint features convenient disassembly, significantly improving maintenance efficiency and enhancing practicality. By pressing button 404 to move the insert rod 401, compressing the spring 403, and disengaging the locking ball 402 from the locking block 4, the fixed relationship between the sliding seat 3 and the connecting seat 201 can be quickly released, enabling convenient disassembly of the first motor 301 without the need for complex tools, thus simplifying the maintenance process. During disassembly, the design of the friction strip 405 reduces component wear, and the spring 403 ensures the reliability of the locking structure's reset, guaranteeing the stability of reassembly after disassembly. The overall structural design balances compactness, adjustment flexibility, and ease of maintenance, making it suitable for installation and use in small spaces for humanoid robots, while also reducing later maintenance costs and improving the long-term operational stability of the robot joint.

[0042] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the present utility model.

Claims

1. A cross-axis robot joint, comprising a mounting base (1), characterized in that: Also includes: A connecting rod (101) is fixedly installed on one side of the mounting base (1); The U-shaped swing arm (2) is located on the outside of the connecting rod (101); A driving component is disposed on one side of the U-shaped swing arm (2), and the driving component is used to drive the U-shaped swing arm (2) to rotate; A sliding seat (3) is provided on the outer side of the bottom end of the U-shaped swing arm (2), and a limiting member is provided on the inner side of the sliding seat (3); A connector is provided on one side of the sliding seat (3).

2. The cross-axis robot joint according to claim 1, characterized in that: The driving component includes: A connecting seat (201) is disposed on one side of the U-shaped swing arm (2); A limiting groove (202) is provided on the inner side of the end of the U-shaped swing arm (2), and the connecting rod (101) is provided on the inner side of the limiting groove (202); An arc-shaped swing arm (203) is fixedly installed on the outer side of the end of the connecting rod (101) away from the mounting base (1); A cross block (205) is disposed on the inner side of the arc-shaped swing arm (203); A cross bar (206) is fixedly installed on the outer sides of both ends of the cross block (205), and the cross block (205) is rotatably connected to the inner side of the arc-shaped swing arm (203) through the cross bar (206); The cross shaft (204) is fixedly installed on the outer sides of both ends of the cross block (205); The fixing plate (207) is fixedly disposed on the upper surface of the connecting seat (201), and the cross shaft (204) is rotatably disposed on the inner side of the end of the fixing plate (207).

3. A cross-axis robot joint according to claim 2, characterized in that: The connecting rod (101) can rotate inside the limiting groove (202), the U-shaped swing arm (2) has a U-shaped structure, and the arc-shaped swing arm (203) can rotate inside the U-shaped swing arm (2).

4. A cross-axis robot joint according to claim 2, characterized in that: The connector includes: The first motor (301) is mounted on the lower surface of the sliding seat (3); The first pulley (302) is fixedly disposed on the outside of the main shaft of the first motor (301); The second pulley (303) is rotatably disposed on one side of the fixed plate (207). The cross shaft (204) passes through the outer end of the fixed plate (207) and is connected to the inner middle part of the arc-shaped swing arm (203). The first pulley (302) and the second pulley (303) are connected by a belt.

5. A cross-axis robot joint according to claim 4, characterized in that: The connector also includes: The first connecting plate (304) is fixedly installed on one side of the first motor (301); The second motor (305) is installed on the inner side of the end of the first connecting plate (304); The second connecting plate (306) is fixedly disposed on one side of the sliding seat (3), and the inner side of the end of the second connecting plate (306) is sleeved on the outer side of the top of the second motor (305); The first bevel gear (307) is fixedly disposed on the outside of the main shaft of the second motor (305); The second bevel gear (308) is fixedly disposed on the outer side of the end of the U-shaped swing arm (2), and the first bevel gear (307) meshes with the second bevel gear (308).

6. A cross-axis robot joint according to claim 4, characterized in that: The limiting component includes: The snap-fit ​​block (4) is movably disposed on the inner side of the bottom end of the connecting seat (201), and the outer side of the end of the snap-fit ​​block (4) is provided with an inclined structure; The insertion rod (401) is movably disposed inside the connector (201); A snap-fit ​​ball (402) is fixedly disposed on the outer side of the middle part of the insert rod (401), and the outer side of the snap-fit ​​ball (402) is in contact with the inner side of the middle part of the snap-fit ​​block (4); A spring (403) is fixedly disposed on the outer side of the end of the insertion rod (401), and the outer side of the end of the spring (403) away from the insertion rod (401) is fixedly connected to the inner side of the bottom end of the connecting seat (201).

7. A cross-axis robot joint according to claim 6, characterized in that: The limiting component also includes: A button (404) is fixedly disposed on the outer side of the end of the plug (401) away from the spring (403), and one side of the button (404) is made of silicone.

8. A cross-axis robot joint according to claim 6, characterized in that: A friction strip (405) is fixedly provided on the outer side of the end of the snap-fit ​​block (4), and the snap-fit ​​block (4) contacts the inner side of the trapezoidal through groove of the sliding seat (3) through the friction strip (405).

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