Grinding device for pre-tightening pipe fitting of automobile safety belt

Abstract

The utility model discloses an automobile safety belt pre-tightening pipe fitting grinding device, which relates to the technical field of bent pipe grinding, and comprises a support, a pre-tightening pipe is accommodated above the support, the automobile safety belt pre-tightening pipe fitting grinding device further comprises a guide pipe, the guide pipe is arranged on one side of the pre-tightening pipe, and the guide pipe is arranged on the other side of the pre-tightening pipe. The two ends of the guide pipe are respectively butted and communicated with the two ends of the pre-tightening pipe; the driving wheel is positioned outside the guide pipe and is used for driving the grinding chain to slide along the interiors of the pre-tightening pipe and the guide pipe; the rotating seat is rotationally arranged in the support, and the pre-tightening pipe and the guide pipe are fixedly installed on the rotating seat. The multiple grinding balls are combined into the grinding chain, the grinding chain slides in the pre-tightening pipe and the guide pipe, the grinding chain slides in the pre-tightening pipe to grind the inner wall, so that the inner wall of the pre-tightening pipe becomes smooth, the device is simple in structure, the effective grinding area is increased through the multiple grinding balls, and the using effect is good.

Description

Technical Field

[0001] The utility model relates to the technical field of elbow pipe grinding, in particular to a grinding device for an automotive seat belt pretensioner pipe fitting. Background Technique

[0002] The pretensioner pipe is used in the pretensioner of the seat belt, playing a guiding role for the internal steel balls to make the steel balls reach the designated positions. Usually, the pretensioner pipe is made into a bent pipe shape (refer to Figure 1 ), so as to be easily installed on the retractor. In order to make the steel balls reach the designated positions within the specified time, it is necessary to ensure that the inner wall of the pretensioner pipe is smooth, avoiding resistance when the steel balls roll inside the pretensioner pipe.

[0003] In the patent with the patent publication number CN113618517B, a device for grinding the inner wall of a multi-bent pipe-shaped casting is proposed. By setting a grinding component and a propulsion component, the grinding head is kept perpendicular to the inner wall of the pipe-shaped casting, so that when the grinding head moves to the rounded corner of the multi-bent pipe-shaped casting, it can still make good contact with the inner wall of the pipe-shaped casting, thus ensuring the grinding effect.

[0004] However, the structure of this device is complex. The inner diameter of the pretensioner pipe is usually 1 cm to 3 cm. It is difficult to make this device into a small size to adapt to the inner diameter of the pretensioner pipe, and the size of the grinding wheel of this device is limited by the overall structure, with a relatively small effective grinding area. Content of the Utility Model

[0005] The utility model provides a grinding device for an automotive seat belt pretensioner pipe fitting, which has the advantages of simple structure, being applicable to pretensioner pipes with small inner diameters, and having a relatively large effective grinding area, so as to solve the problems raised in the background technique.

[0006] To achieve the purpose of having a simple structure, being applicable to pretensioner pipes with small inner diameters, and having a relatively large effective grinding area, the utility model provides the following technical solution: A grinding device for an automotive seat belt pretensioner pipe fitting, including a support. A pretensioner pipe is accommodated above the support. It further includes: a guiding pipe, which is arranged on one side of the pretensioner pipe. The two ends of the guiding pipe are respectively butted and communicated with the two ends of the pretensioner pipe, and the inner diameter of the guiding pipe is the same as that of the pretensioner pipe; grinding balls, which are arranged in the guiding pipe. There are multiple grinding balls, and the multiple grinding balls are combined into a grinding chain, and the grinding chain is a single non-closed chain; a driving wheel, which is located outside the guiding pipe and is used to drive the grinding chain to slide along the inside of the pretensioner pipe and the guiding pipe, so that when the grinding chain passes through the pretensioner pipe, the inner wall of the pretensioner pipe is polished; the grinding balls in the pretensioner pipe can always contact the lower surface of the inner wall of the pretensioner pipe under the action of gravity; a rotating seat, which is rotatably arranged in the support, and the pretensioner pipe and the guiding pipe are fixedly installed on the rotating seat, so that when the rotating seat rotates, different positions of the inner wall of the pretensioner pipe serve as the lower surface of the inner wall of the pretensioner pipe.

[0007] As a preferred technical solution of the present utility model, a storage cylinder is fixedly arranged above the rotating seat, and a fork pipe is communicated between the storage cylinder and the guide pipe; a through hole is opened at the connection between the fork pipe and the guide pipe, a guide plate is arranged directly below the through hole, the receiving surface of the guide plate is inclined towards the fork pipe, a cylinder is fixedly arranged below the guide plate, the piston rod of the cylinder is fixedly connected with the guide plate, and the guide plate is used for inserting into the through hole so that the end of the grinding chain contacts the guide plate and deflects into the fork pipe.

[0008] As a preferred technical solution of the present utility model, a strip-shaped opening is provided, the strip-shaped opening is arranged along the axial direction of the guide pipe on the straight section of the guide pipe, and the strip-shaped opening is located on the side of the fork pipe for receiving the grinding chain; the driving wheel is installed on the rotating seat through a bearing seat, and the driving wheel is opposite to the strip-shaped opening, and the upper part of the driving wheel is inserted into the interior of the guide pipe through the strip-shaped opening; a plurality of concave grooves are formed on the outer peripheral surface of the driving wheel, and the concave grooves are fitted with the grinding balls so that the driving wheel meshes with the grinding chain; a second motor is fixedly arranged on the rotating seat, and a bevel gear set is arranged between the second motor and the driving wheel, one shaft end of the bevel gear set is fixedly connected with the output end of the second motor, and the other shaft end of the bevel gear set is fixedly connected with the center of the driving wheel.

[0009] As a preferred technical solution of the present utility model, the middle section of the grinding ball is cylindrical, and both ends of the grinding ball are ellipsoidal; a ball groove is opened at one end of the grinding ball, a connecting ball is arranged at the other end of the grinding ball, and the connecting ball on one grinding ball is fitted into the ball groove of the other connecting ball to form a grinding chain.

[0010] As a preferred technical solution of the present utility model, a connecting rod is fixedly arranged on the side of the connecting ball close to the grinding ball, a receiving cavity is opened inside the grinding ball close to the connecting ball, one end of the connecting rod penetrates through the grinding ball and is inserted into the receiving cavity, a retaining ring is fixedly arranged at the end of the connecting rod located inside the receiving cavity, and a first spring and a second spring are respectively arranged on both sides of the retaining ring inside the receiving cavity.

[0011] As a preferred technical solution of the present utility model, sleeve pipes are sleeved on both ends of the guide pipe, a socket part, a communicating part and a threaded part are sequentially opened inside the sleeve pipe, one end of the pre-tightening pipe is inserted into the socket part, the inner diameter of the communicating part is the same as the inner diameter of the guide pipe, and the threaded part is threadedly connected with the guide pipe.

[0012] As a preferred technical solution of the present utility model, a first motor is fixedly arranged on one side of the support, and the first motor is used for driving the rotating seat to rotate.

[0013] Compared with the prior art, the present utility model provides a grinding device for an automobile seat belt pre-tightening pipe fitting, and has the following beneficial effects:

[0014] 1. The grinding device for the pre-tightening pipe fitting of the vehicle seat belt, by setting the guide pipe and the grinding balls, combines multiple grinding balls into a grinding chain. The grinding chain slides inside the pre-tightening pipe and the guide pipe, so as to grind the inner wall of the pre-tightening pipe by the sliding of the grinding chain inside the pre-tightening pipe, making the inner wall of the pre-tightening pipe smooth. The device has a simple structure, and the use of multiple grinding balls increases the effective grinding area, with good use effect.

[0015] 2. The grinding device for the pre-tightening pipe fitting of the vehicle seat belt, by setting the rotating seat and fixing the guide pipe and the pre-tightening pipe on the rotating seat, enables the pre-tightening pipe to rotate continuously along with the rotation of the rotating seat. During the continuous rotation of the pre-tightening pipe, each position on its inner wall serves as the lower surface of the inner wall at different time periods, that is, each position on the inner wall of the pre-tightening pipe can be ground by the grinding balls, so that the grinding chain can grind the inner wall of the pre-tightening pipe in all directions when sliding inside the pre-tightening pipe, ensuring the grinding quality.

[0016] 3. The grinding device for the pre-tightening pipe fitting of the vehicle seat belt, by opening a receiving cavity in the grinding ball and respectively arranging a first spring and a second spring on both sides of the retaining ring in the receiving cavity, enables adjacent two grinding balls to be subjected to the acting forces of the first spring and the second spring when the grinding ball contacts the driving wheel, thus playing a buffering role and reducing the vibration and noise during the operation of the device. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of the pre-tightening pipe;

[0018] Figure 2 It is a schematic structural diagram of the present utility model;

[0019] Figure 3 It is a schematic diagram of the installation position of the pre-tightening pipe and the guide pipe of the present utility model;

[0020] Figure 4 It is a diagram of the positional relationship among the guide pipe, the sleeve pipe and the pre-tightening pipe of the present utility model;

[0021] Figure 5 It is a schematic diagram of the installation position of the driving wheel and the guide pipe of the present utility model;

[0022] Figure 6 It is the present utility model Figure 5 The enlarged schematic diagram of area A in;

[0023] Figure 7 It is a cross-sectional view of the grinding ball of the present utility model;

[0024] Figure 8 It is a schematic structural diagram of the driving wheel of the present utility model;

[0025] Figure 9This is a cross-sectional view of the sleeve pipe of the present utility model.

[0026] In the figure: 1, pre-tightening pipe; 2, support; 3, rotating seat; 4, first motor; 5, guide pipe; 6, fork pipe; 7, storage cylinder; 8, return pipe; 9, driving wheel; 901, concave groove; 902, notch groove; 10, strip-shaped opening; 11, grinding ball; 1101, ball groove; 1102, accommodating cavity; 12, bevel gear set; 13, second motor; 14, guide plate; 15, cylinder; 16, connecting ball; 17, connecting rod; 18, retaining ring; 19, first spring; 20, second spring; 21, sleeve pipe; 2101, socket part; 2102, communicating part; 2103, threaded part; 22, through hole. Specific embodiments

[0027] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0028] Please refer to Figure 2 - Figure 5 , the present utility model discloses a grinding device for an automobile seat belt pre-tightening pipe fitting, including a support 2. A pre-tightening pipe 1 is accommodated above the support 2. The pre-tightening pipe 1 is used in the pre-tightening device of the seat belt, and plays a guiding role for the internal steel balls, so that the steel balls reach the specified positions. Usually, the pre-tightening pipe 1 is made into a bent pipe shape to facilitate installation on the retractor. In order to make the steel balls reach the specified positions within a specified time, it is necessary to ensure that the inside of the pre-tightening pipe 1 is smooth, so that the steel balls are not resisted when rolling inside. This device is used to grind the inside of the pre-tightening pipe 1 so that the surface quality of the inside of the pre-tightening pipe 1 meets the requirements.

[0029] It further includes a guide pipe 5. The guide pipe 5 is arranged on one side of the pre-tightening pipe 1. Since the pre-tightening pipe 1 is in a bent pipe shape and the two ends of the pre-tightening pipe 1 are not at the same height, the guide pipe 5 also needs to be set in a bent pipe shape matching the pre-tightening pipe 1, and the two ends of the guide pipe 5 are respectively butted and communicated with the two ends of the pre-tightening pipe 1, and the inner diameter of the guide pipe 5 is set to be the same as the inner diameter of the pre-tightening pipe 1.

[0030] A plurality of grinding balls 11 are further arranged in the guide pipe 5. The plurality of grinding balls 11 are combined into a grinding chain, and the grinding chain is a single non-closed chain. The grinding chain slides inside the pre-tightening pipe 1 and the guide pipe 5, so as to grind the inner wall of the pre-tightening pipe 1 through the sliding of the grinding chain inside the pre-tightening pipe 1, making the inner wall of the pre-tightening pipe 1 smooth.

[0031] Therefore, the grinding device for the pre-tightening pipe fitting of the vehicle seat belt provided by the utility model can polish the inner wall of the pre-tightening pipe in the form of continuous movement of a single grinding chain, which is convenient for grinding and has a good grinding effect.

[0032] In addition, a driving wheel 9 is also installed on the rotating seat 3, and the driving wheel 9 is located outside the guiding pipe 5. When the grinding chain passes through the position corresponding to the driving wheel 9 in the guiding pipe 5, it contacts the driving wheel 9, and the driving wheel 9 throws the grinding chain along the tangent direction of the driving wheel 9 to provide power for the sliding of the grinding chain, thereby driving the grinding chain to slide along the inside of the pre-tightening pipe 1 and the guiding pipe 5, so that when the grinding chain passes through the inside of the pre-tightening pipe 1, it polishes the inner wall of the pre-tightening pipe 1. The rotation speed of the driving wheel 9 should meet the requirement that after the grinding chain separates from the driving wheel 9, it can move along the inside of the guiding pipe 5 and the pre-tightening pipe 1 for one week and contact the driving wheel 9 again.

[0033] In the actual application scenario, the middle diameter of the grinding ball 11 should be slightly smaller than the inner diameter of the pre-tightening pipe 1 to avoid the situation that the grinding ball 11 is difficult to move in the pre-tightening pipe 1. However, this operation will cause the grinding ball 11 to always fit on the lower surface of the inner wall of the pre-tightening pipe 1 under the action of gravity, resulting in that it can only polish the lower surface of the inner wall of the pre-tightening pipe. Therefore, in order to solve this problem, a rotating seat 3 is also provided above the support 2, the two sides of the rotating seat 3 are rotatably connected to the support 2, the rotation axis of the rotating seat 3 is set to be parallel to the horizontal plane, and then the pre-tightening pipe 1 and the guiding pipe 5 are fixedly installed on the rotating seat 3. Thus, when the rotating seat 3 rotates, the pre-tightening pipe 1 can also rotate continuously. During the continuous rotation of the pre-tightening pipe 1, each position of its inner wall serves as the lower surface of the inner wall at different time periods, that is, each position of the inner wall of the pre-tightening pipe 1 can be ground by the grinding ball 11, so that when the grinding chain slides inside the pre-tightening pipe 1, it can grind the inner wall of the pre-tightening pipe 1 in all directions, ensuring the grinding quality.

[0034] Combined with Figure 1 , in order to make the grinding chain separate from the guiding pipe 5 so as to facilitate the removal of the pre-tightening pipe 1, a receiving cylinder 7 is fixedly provided above the rotating seat 3, and a fork pipe 6 is connected between the receiving cylinder 7 and the guiding pipe 5, and the grinding chain can enter the receiving cylinder 7 through the fork pipe 6.

[0035] In addition, combined with Figure 5 and Figure 6 , in order to change the moving direction of the grinding chain in the guiding pipe 5, a through hole 22 is opened at the connection between the fork pipe 6 and the guiding pipe 5, a guiding plate 14 is provided directly below the through hole 22, the receiving surface of the guiding plate 14 is inclined towards the fork pipe 6, and a cylinder 15 is fixedly provided below the guiding plate 14. The piston rod of the cylinder 15 is fixedly connected to the guiding plate 14, and the guiding plate 14 is used to insert into the through hole 22 so that the end of the grinding chain contacts the guiding plate 14 and deflects into the fork pipe 6.

[0036] Specifically, a photoelectric sensor may be provided on the side where the driver 9 receives the grinding chain to determine whether the grinding chain reaches the specified position. When the grinding chain slides the last lap during grinding, the photoelectric sensor measures the position of the grinding chain, and the cylinder 15 is activated to push the guide plate 14 into the through hole 22. When the grinding chain reaches the through hole 22, the head of the grinding chain contacts the guide plate 14 and changes the direction of movement, thus turning to the fork tube 6 and entering the storage cylinder 7 through the fork tube 6.

[0037] Optionally, a spiral pipeline may be provided in the storage cylinder 7, and a return pipe 8 is provided at one end of the storage cylinder 7 away from the fork tube 6. One end of the return pipe 8 is communicated with the guide pipe 5, the other end of the return pipe 8 is communicated with the pipeline in the storage cylinder 7, and a driving device for driving the grinding chain is provided in the storage cylinder 7, so that the grinding chain entering the storage cylinder 7 can enter the guide pipe 5 again through the return pipe 8, thereby improving the convenience of using the device.

[0038] Combined with Figure 5 , in order to facilitate the driving wheel 9 to drive the grinding chain to move, a strip-shaped opening 10 is provided in the straight section of the guide pipe 5. The strip-shaped opening 10 is located on the side where the fork tube 6 receives the grinding chain, and the length direction of the strip-shaped opening 10 is parallel to the axial direction of the guide pipe 5 in the straight section.

[0039] Moreover, the driving wheel 9 is installed on the rotating seat 3 through a bearing seat, so that the position of the driving wheel 9 is opposite to the strip-shaped opening 10, and the upper part of the driving wheel 9 is inserted into the inside of the guide pipe 5 through the strip-shaped opening 10.

[0040] In addition, combined with Figure 8 , a plurality of concave grooves 901 are provided on the outer peripheral surface of the driving wheel 9. The concave grooves 901 are fitted with the grinding balls 11, so that the driving wheel 9 meshes with the grinding chain. The grinding balls 11 can enter the concave grooves 901 and move a certain distance in the rotating direction of the driving wheel 9 under the rotation of the driving wheel 9, thereby causing the whole grinding chain to move.

[0041] Furthermore, combined with Figure 5 , in order to drive the driving wheel 9 to rotate, a second motor 13 is fixedly provided on the rotating seat 3, and a bevel gear set 12 is provided between the second motor 13 and the driving wheel 9. One shaft end of the bevel gear set 12 is fixedly connected to the output end of the second motor 13, and the other shaft end of the bevel gear set 12 is fixedly connected to the axis center of the driving wheel 9, so that the second motor 13 drives the driving wheel 9 to rotate through the bevel gear set 12.

[0042] Combined with Figure 6 and Figure 7 , the middle section of the outer surface of the grinding ball 11 is cylindrical to increase the contact area between the grinding ball 11 and the inner wall of the pre-tightening pipe 1. The two ends of the grinding ball 11 are ellipsoidal to facilitate the movement of the grinding ball 11 in the elbow pipe.

[0043] In addition, in order to form a grinding chain with multiple grinding balls 11, a ball groove 1101 is provided at one end of the grinding ball 11, and a connecting ball 16 is provided at the other end of the grinding ball 11. The connecting ball 16 fits with the ball groove 1101. By fitting the connecting ball 16 on one grinding ball 11 into the ball groove 1101 of another connecting ball 16, multiple grinding balls 11 can be combined together to form a grinding chain.

[0044] Combined with Figure 7 , in order to buffer the collision when the grinding chain contacts the driving wheel 9, a connecting rod 17 is fixedly provided on the side of the connecting ball 16 close to the grinding ball 11, and an accommodating cavity 1102 is provided inside the grinding ball 11 on the side close to the connecting ball 16. One end of the connecting rod 17 penetrates through the grinding ball 11 and is inserted into the accommodating cavity 1102. A retaining ring 18 is fixedly provided at one end of the connecting rod 17 located inside the accommodating cavity 1102, and a first spring 19 and a second spring 20 are respectively provided on both sides of the retaining ring 18 inside the accommodating cavity 1102. Thus, when the grinding ball 11 contacts the driving wheel 9, adjacent two grinding balls 11 can be subjected to the acting forces of the first spring 19 and the second spring 20, thereby playing a buffering role.

[0045] Combined with Figure 8 , since a connecting rod 17 is provided between the connecting ball 16 and the grinding ball 11, correspondingly, a notch groove 902 is provided on the outer edge of the driving wheel and between two adjacent concave grooves 901. The notch groove 902 fits with the connecting rod 17.

[0046] Combined with Figure 9 , in order to facilitate the disassembly and assembly of the pre-tightening pipe 1, sleeve pipes 21 are sleeved on both ends of the guiding pipe 5. The pre-tightening pipe 1 is connected to the guiding pipe 5 through the sleeve pipes 21. A socket part 2101, a communicating part 2102 and a threaded part 2103 are successively provided inside the sleeve pipe 21. One end of the pre-tightening pipe 1 is inserted into the socket part 2101, thereby fixing the pre-tightening pipe 1. The inner diameter of the communicating part 2102 is the same as the inner diameter of the guiding pipe 5 to facilitate the grinding chain to pass through the sleeve pipe 21. The threaded part 2103 is threadedly connected to the guiding pipe 5. When installing the pre-tightening pipe 1, rotate the sleeve pipe 21 to make the sleeve pipe 21 move towards one end of the guiding pipe 5. After aligning the position of the pre-tightening pipe 1, rotate the sleeve pipe 21 in the reverse direction to make the sleeve pipe 21 move towards the pre-tightening pipe 1, so that the pre-tightening pipe 1 is inserted into the socket part 2101, and then the fixing of the pre-tightening pipe 1 is completed.

[0047] Combined with Figure 2 , in order to drive the rotating seat 3 to rotate, a first motor 4 is fixedly provided on one side of the support 2, and the output end of the first motor 4 is fixedly connected to the rotation axis center of the rotating seat 3.

[0048] Working principle and usage process of the present utility model: When in use, rotate the sleeve pipe 21 to move the sleeve pipe 21 towards one end of the guiding pipe 5. After aligning the position of the pre-tightening pipe 1, rotate the sleeve pipe 21 in the reverse direction to complete the fixation of the pre-tightening pipe 1. Start the second motor 13 to drive the driving wheel 9. The driving wheel 9 drives the grinding chain to move through the concave groove 901. The grinding chain enters the pre-tightening pipe 1 through the guiding pipe 5 to grind the inner wall of the pre-tightening pipe 1. Then start the first motor 4 to drive the rotating seat 3 to rotate. After grinding is completed, start the cylinder 15 to push the guiding plate 14 into the through hole 22. The head of the grinding chain contacts the guiding plate 14 and changes the direction of movement, thus turning to the fork pipe 6 and entering the receiving cylinder 7 through the fork pipe 6. After that, rotate the sleeve pipe 21 in the reverse direction to remove the pre-tightening pipe 1.

[0049] In summary, for this grinding device for automotive seat belt pre-tightening pipe fittings, by setting the guiding pipe 5 and the grinding balls 11, multiple grinding balls 11 are combined into a grinding chain. The grinding chain slides inside the pre-tightening pipe 1 and the guiding pipe 5, so as to grind the inner wall of the pre-tightening pipe 1 through the sliding of the grinding chain inside the pre-tightening pipe 1, making the inner wall of the pre-tightening pipe 1 smooth. The device has a simple structure. The use of multiple grinding balls 11 increases the effective grinding area and has a good use effect. By setting the rotating seat 3 and fixing the guiding pipe 5 and the pre-tightening pipe 1 on the rotating seat 3, while the grinding chain slides inside the pre-tightening pipe 1, it can also rotate with the rotating seat 3. The grinding chain can roll relative to the inner wall of the pre-tightening pipe 1, so as to grind the inner wall of the pre-tightening pipe 1 more comprehensively. By opening a receiving cavity 1102 in the grinding ball 11 and respectively arranging a first spring 19 and a second spring 20 on both sides of the retaining ring 18 in the receiving cavity 1102, when the grinding ball 11 contacts the driving wheel 9, adjacent two grinding balls 11 can be subjected to the acting forces of the first spring 19 and the second spring 20, thus playing a buffering role and reducing the vibration and noise during the operation of the device.

[0050] It should be noted that in this article, terms such as "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitations, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0051] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A grinding device for a pre-tensioning pipe of an automobile seat belt, comprising a support (2), a pre-tensioning pipe (1) being accommodated above the support (2), characterized in that: Also includes: A guide tube (5), the guide tube (5) being arranged on one side of the preload tube (1), the two ends of the guide tube (5) being butt-connected and connected to the two ends of the preload tube (1), and the inner diameter of the guide tube (5) being the same as the inner diameter of the preload tube (1); A grinding ball (11), wherein the grinding ball (11) is arranged in the guide tube (5), a plurality of the grinding balls (11) are provided, and the plurality of grinding balls (11) are combined into a grinding chain, and the grinding chain is a single non-enclosed chain; a driving wheel (9), the driving wheel (9) being located outside the guide tube (5) and being used to drive the grinding chain to slide along the inside of the pretensioning tube (1) and the guide tube (5), so that the grinding chain grinds the inner wall of the pretensioning tube (1) when passing through the pretensioning tube (1); The grinding balls (11) in the preload tube (1) can always be in contact with the lower surface of the inner wall of the preload tube (1) under the action of gravity; A rotating seat (3), the rotating seat (3) is rotatably arranged in the support (2), and the preload tube (1) and the guide tube (5) are fixedly mounted on the rotating seat (3), so that when the rotating seat (3) rotates, the inner wall of the preload tube (1) serves as the lower surface of the inner wall of the preload tube (1) at different positions.

2. The automobile seat belt pre-tensioning pipe grinding device according to claim 1 is characterized in that: A storage cylinder (7) is fixedly provided above the rotating seat (3), and a fork tube (6) is connected between the storage cylinder (7) and the guide tube (5); A through hole (22) is provided at the connection point between the fork tube (6) and the guide tube (5), a guide plate (14) is provided directly below the through hole (22), a facing surface of the guide plate (14) is inclined toward the fork tube (6), a cylinder (15) is fixedly provided below the guide plate (14), a piston rod of the cylinder (15) is fixedly connected to the guide plate (14), and the guide plate (14) is used to be inserted into the through hole (22) so that the end of the grinding chain contacts the guide plate (14) and deflects into the fork tube (6).

3. The automobile seat belt pretensioner pipe grinding device according to claim 1, characterized in that: Also includes: a strip-shaped opening (10), the strip-shaped opening (10) being opened in the straight section of the guide tube (5) along the axial direction of the guide tube (5), and the strip-shaped opening (10) being located on a side of the fork tube (6) that meets the grinding chain; The driving wheel (9) is mounted on the rotating seat (3) via a bearing seat, and the driving wheel (9) is opposite to the strip-shaped opening (10), and the upper part of the driving wheel (9) is inserted into the interior of the guide tube (5) through the strip-shaped opening (10); The outer peripheral surface of the driving wheel (9) is provided with a plurality of concave grooves (901), and the concave grooves (901) fit with the grinding balls (11) so that the driving wheel (9) meshes with the grinding chain; A second motor (13), the second motor (13) being fixedly mounted on the rotating seat (3), a bevel gear set (12) being arranged between the second motor (13) and the driving wheel (9), one shaft end of the bevel gear set (12) being fixedly connected to an output end of the second motor (13), and the other shaft end of the bevel gear set (12) being fixedly connected to the axis of the driving wheel (9).

4. The automobile safety belt pretensioning pipe grinding device according to claim 1 is characterized in that: The middle section of the grinding ball (11) is cylindrical, and both ends of the grinding ball (11) are ellipsoidal; One end of the grinding ball (11) is provided with a ball groove (1101), and the other end of the grinding ball (11) is provided with a connecting ball (16); the connecting ball (16) on one grinding ball (11) is embedded in the ball groove (1101) of another connecting ball (16) to form a grinding chain.

5. The automobile safety belt pretensioning pipe grinding device according to claim 4 is characterized in that: A connecting rod (17) is fixedly provided on a side of the connecting ball (16) close to the grinding ball (11); a receiving cavity (1102) is provided inside the side of the grinding ball (11) close to the connecting ball (16); one end of the connecting rod (17) passes through the grinding ball (11) and is inserted into the receiving cavity (1102); a retaining ring (18) is fixedly provided on one end of the connecting rod (17) located in the receiving cavity (1102); and a first spring (19) and a second spring (20) are respectively provided on both sides of the retaining ring (18) in the receiving cavity (1102).

6. The automobile safety belt pretensioning pipe grinding device according to any one of claims 1 to 5, characterized in that: Both ends of the guide tube (5) are sleeved with a sleeve tube (21), the interior of the sleeve tube (21) is provided with a sleeve connection portion (2101), a connecting portion (2102) and a threaded portion (2103) in sequence, one end of the preload tube (1) is inserted into the sleeve connection portion (2101), the inner diameter of the connecting portion (2102) is the same as the inner diameter of the guide tube (5), and the threaded portion (2103) is threadedly connected to the guide tube (5).

7. The automobile safety belt pre-tensioning pipe grinding device according to claim 1 is characterized in that: A first motor (4) is fixedly disposed on one side of the support (2), and the first motor (4) is used to drive the rotating seat (3) to rotate.

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