CN223465805U - A pneumatic positioning and clamping tool for welding the front triangle of a bicycle frame - Google Patents

Abstract

A front triangle part welding pneumatic positioning and clamping tool of a bicycle frame comprises a base, a head pipe positioning and clamping mechanism, an upper pipe positioning and clamping mechanism, a lower pipe positioning and clamping mechanism, a vertical pipe positioning and clamping mechanism and a five-way pipe positioning and clamping mechanism, wherein the base is provided with a workbench with a rectangular frame structure, the head pipe positioning and clamping mechanism is arranged on the short side of the rectangular frame and is provided with a head pipe pneumatic positioning and clamping assembly, the upper pipe positioning and clamping mechanism, the lower pipe positioning and clamping mechanism and the vertical pipe positioning and clamping mechanism are respectively assembled with the rectangular frame in a detachable mode, the upper pipe pneumatic positioning and clamping assembly, the lower pipe pneumatic positioning and clamping assembly and the vertical pipe positioning and clamping assembly are arranged in the vertical pipe positioning and clamping mechanism, and the five-way pipe positioning and clamping mechanism is arranged on the lower part of the vertical pipe positioning and clamping mechanism and is provided with the five-way pipe pneumatic positioning and clamping assembly. The utility model can be matched with front triangle welding processes of different types of bicycle frames, thereby achieving the purposes of improving the welding quality and working efficiency of workpieces and reducing the production cost.

Description

Pneumatic positioning and clamping tool for welding front triangular part of bicycle frame

Technical Field

The utility model relates to the technical field of bicycle production equipment, in particular to a pneumatic positioning and clamping tool for welding a front triangle part of a bicycle frame.

Background

As shown in figure 1, the front triangle part 1 of the bicycle frame consists of a head pipe 1-1, an upper pipe 1-2, a lower pipe 1-5, a vertical pipe 1-3 and a five-way pipe 1-4, and the components are generally combined into a whole by adopting a common carbon steel pipe through a welding process. Because the bicycle runs by means of human driving force and riding skill, the frame becomes an important structural body for carrying human body and bearing impact load in the running process of the bicycle, and the manufacturing precision of the bicycle is good and bad, the riding safety and stability are directly affected, so that the welding operation of the bicycle frame becomes one of key control procedures in the production process of the bicycle. In addition, because of the variety of bicycle types and specification models, the shapes and the sizes of different types of bicycle frames are different, and in order to meet the requirements of universality, improve the working efficiency and reduce the production cost, the positioning and clamping tool for workpieces in the welding process of the bicycle frames is required to be improved.

Disclosure of utility model

The utility model provides a pneumatic positioning and clamping tool for welding front triangle parts of bicycle frames, which aims to match the front triangle welding process of different types of bicycle frames by matching a base, a head pipe positioning and clamping mechanism, an upper pipe and lower pipe positioning and clamping mechanism, a vertical pipe positioning and clamping mechanism and a five-way pipe positioning and clamping mechanism, so as to achieve the aims of improving the welding quality and working efficiency of workpieces and reducing the production cost.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

A front triangle part welding pneumatic positioning and clamping tool of a bicycle frame comprises a base, a head pipe positioning and clamping mechanism, an upper pipe positioning and clamping mechanism, a lower pipe positioning and clamping mechanism, a vertical pipe positioning and clamping mechanism and a five-way pipe positioning and clamping mechanism, wherein the base is provided with a workbench of a rectangular frame structure, the workbench is fixed on the horizontal ground, a plurality of groups of assembly holes are formed in two long sides of the rectangular frame, the head pipe positioning and clamping mechanism is arranged on the short side of the rectangular frame and is provided with a head pipe pneumatic positioning and clamping assembly capable of being adjusted in the upper and lower positions, the upper pipe positioning and clamping mechanism and the vertical pipe positioning and clamping mechanism are respectively assembled with the assembly holes of the rectangular frame in a detachable mode, the upper pipe pneumatic positioning and clamping assembly capable of realizing angle adjustment and vertical position adjustment is arranged in the upper pipe positioning and clamping mechanism, the vertical pipe positioning and clamping assembly is arranged in the vertical pipe positioning and clamping mechanism, the five-way pipe positioning and clamping mechanism is arranged on the lower part of the vertical pipe positioning and clamping mechanism.

The pneumatic positioning and clamping assembly for the front triangular part of the bicycle frame comprises two parts which are arranged up and down, wherein an upper pipe positioning unit, a lower pipe pressing unit, an upper pipe positioning unit, a lower pipe pressing unit and an L-shaped support are arranged in each part, and are assembled with the vertical sliding grooves of the L-shaped support.

The pneumatic positioning and clamping tool for welding the front triangle part of the bicycle frame is characterized in that the upper tube and lower tube positioning unit comprises a positioning block and a positioning seat, the positioning seat is of a T-shaped seat structure, a stud is arranged at the tail of the positioning seat, the stud penetrates through a vertical chute of an L-shaped support and is fixed through a fixing block and a locking nut, the positioning block is arranged at two ends of the head of the positioning seat, and arc-shaped positioning grooves matched with the outer surfaces of the upper tube and lower tube workpieces are formed in the positioning block.

The pneumatic positioning and clamping tool for welding the front triangle part of the bicycle frame is characterized in that the upper and lower pipe pressing units comprise pressing seats, rotating cylinders and upper and lower pipe pressing heads, studs are arranged at the tail parts of the pressing seats, the studs penetrate through vertical sliding grooves of the L-shaped support and are fixed through fixing blocks and locking nuts, the rotating cylinders are arranged at the heads of the pressing seats, and the upper and lower pipe pressing heads are arranged on rotating telescopic arms of the rotating cylinders.

The pneumatic positioning and clamping fixture for welding the front triangle part of the bicycle frame comprises a head pipe positioning block, an adjustable connecting seat and a head pipe clamping cylinder, wherein the head pipe positioning block is vertically arranged in two groups, each group of head pipe positioning blocks is provided with a V-shaped positioning groove, the bottom of the lower group of head pipe positioning blocks is provided with a supporting plate for limiting the height position of the head pipe, and a telescopic arm of the head pipe clamping cylinder is connected with the head pipe positioning block through the adjustable connecting seat.

The pneumatic positioning and clamping tool for welding the front triangular part of the bicycle frame is characterized in that the vertical pipe positioning and clamping mechanism is further provided with a U-shaped support, the two vertical arms of the U-shaped support are different in height and are in a front low-back high state, the vertical pipe upper end pneumatic compression assembly and the vertical pipe positioning assembly are arranged on the vertical arms behind the U-shaped support, the vertical pipe upper end pneumatic compression assembly comprises a vertical pipe compression cylinder and a vertical pipe pressure head, the vertical pipe compression cylinder is vertically arranged, the telescopic arms of the vertical pipe compression cylinder move up and down, and the vertical pipe pressure head is arranged on the telescopic arms of the vertical pipe compression cylinder.

The pneumatic positioning and clamping tool for welding the front triangular part of the bicycle frame is characterized in that the vertical pipe positioning assembly comprises two parts which are arranged up and down, and each part is provided with an arc-shaped positioning groove matched with the outer surface of the vertical pipe in the front triangular part of the bicycle frame.

The pneumatic positioning and clamping tool for welding the front triangular part of the bicycle frame is characterized in that a five-way pipe pneumatic positioning and clamping assembly in the five-way pipe positioning and clamping mechanism comprises a five-way pipe compressing cylinder and a five-way pipe pressing head, wherein the five-way pipe compressing cylinder is arranged on a front vertical arm of a U-shaped support of the vertical pipe positioning and clamping mechanism, two groups of the five-way pipe pressing heads are oppositely arranged front and back, one group of the five-way pipe pressing head is fixedly arranged on the lower part of a rear vertical arm of the U-shaped support of the vertical pipe positioning and clamping mechanism, and the other group of the five-way pipe pressing cylinder is arranged on a telescopic arm of the five-way pipe compressing cylinder.

The pneumatic positioning and clamping tool for welding the front triangle part of the bicycle frame is further provided with a group of cylinder action control handles, and the cylinder action control handles are arranged on the front vertical face of the rectangular frame of the base.

The utility model provides a pneumatic positioning and clamping tool for welding a front triangle part of a bicycle frame, wherein a head pipe positioning and clamping mechanism, an upper pipe positioning and clamping mechanism, a lower pipe positioning and clamping mechanism, a vertical pipe positioning and clamping mechanism and a five-way pipe positioning and clamping mechanism all adopt a cylinder driving mode, and a cylinder action control handle is arranged on the front vertical face of a rectangular frame of a base, so that the consistency of workpiece clamping force is ensured through pneumatic control, and the convenience of operation is improved. According to the utility model, the workbench of the base is designed into a rectangular frame structure, and the two long sides of the rectangular frame are fixedly assembled with the L-shaped support horizontal arm of the upper and lower pipe positioning and clamping mechanism and the U-shaped support bottom edge of the vertical pipe positioning and clamping mechanism in a detachable manner, so that the stability and reliability of the upper and lower pipe positioning and clamping mechanism, the vertical pipe positioning and clamping mechanism and the five-way pipe positioning and clamping mechanism are greatly improved, the welding quality and the assembly precision of workpieces are ensured, and the universality of the utility model is improved. In a word, the utility model can match the front triangle welding process of different types of bicycle frames through the matching of the base, the head pipe positioning and clamping mechanism, the upper and lower pipe positioning and clamping mechanism, the vertical pipe positioning and clamping mechanism and the five-way pipe positioning and clamping mechanism, thereby achieving the purposes of improving the welding quality and the working efficiency of workpieces and reducing the production cost.

Drawings

FIG. 1 is a schematic view of the front triangle of a bicycle frame;

FIG. 2 is a schematic diagram of the overall structure of the present utility model;

FIG. 3 is a schematic view of a tube up and down positioning and clamping mechanism;

FIG. 4 is a schematic view of the structure of FIG. 3 after being rotated horizontally by a certain angle;

FIG. 5 is a schematic view of the structure of the upper and lower tube positioning unit;

FIG. 6 is a schematic view of the structure of the upper and lower pipe compressing unit;

FIG. 7 is a schematic view of the operation of the present utility model;

Fig. 8 is a K-direction view of fig. 7.

The reference numerals in the drawings are defined as follows:

1 is a front triangle part of a bicycle frame, 1-1 is a head pipe, 1-2 is an upper pipe, 1-3 is a vertical pipe, 1-4 is a five-way pipe, and 1-5 is a lower pipe;

2 is a base, 2-1 is a rectangular frame, and 2-2 is an assembly hole;

3 is a head pipe positioning and clamping mechanism, 3-1 is a head pipe clamping cylinder, 3-2 is a head pipe positioning block, and 3-3 is an adjustable connecting seat;

4 is an upper and lower pipe positioning and clamping mechanism, 4-1 is an L-shaped support, 4-1-1 is a vertical chute, 4-2 is a supporting plate, 4-2-1 is a horizontal chute, 4-3 is a compression seat, 4-4 is a rotary cylinder, 4-5 is an upper and lower pipe pressure head, 4-6 is a positioning block, 4-7 is a positioning seat, 4-8 is a fixed block, 4-9 is a stud, and 4-10 is a lock nut;

5 is a vertical pipe positioning and clamping mechanism, 5-1 is a vertical pipe compression cylinder, 5-2 is a vertical pipe pressure head, 5-3 is a vertical pipe positioning component, and 5-4 is a U-shaped support;

6 is a five-way pipe positioning and clamping mechanism, 6-1 is a five-way pipe compression cylinder, and 6-2 is a five-way pipe pressure head;

And 7 is a cylinder action control handle.

Detailed Description

The utility model will be further described with reference to the accompanying drawings and specific examples.

Referring to fig. 1, a front triangle part 1 of a common bicycle frame is composed of a head pipe 1-1, an upper pipe 1-2, a lower pipe 1-5, a vertical pipe 1-3 and a five-way pipe 1-4, wherein the components are combined into a whole by adopting a common carbon steel pipe through a welding process. The welding positions of the respective constituent parts of the front triangle part 1 of the bicycle frame are different due to the variety of the bicycle types and specifications, and the structural features of the present utility model will be described with reference to the front triangle part 1 of the bicycle frame shown in fig. 1 as a specific example.

Referring to fig. 2, 7 and 8, the utility model provides a pneumatic positioning and clamping fixture for welding a front triangle part of a bicycle frame, which comprises a base 2, a head pipe positioning and clamping mechanism 3, an upper pipe and lower pipe positioning and clamping mechanism 4, a vertical pipe positioning and clamping mechanism 5 and a five-way pipe positioning and clamping mechanism 6; the base 2 is provided with a workbench with a rectangular frame structure, the workbench is fixed on the horizontal ground, two long sides of the rectangular frame 2-1 are provided with a plurality of groups of assembly holes 2-2, the head pipe positioning and clamping mechanism 3 is arranged on one short side of the rectangular frame 2-1 and is provided with a head pipe pneumatic positioning and clamping assembly capable of adjusting the upper and lower positions, the upper and lower pipe positioning and clamping mechanism 4 and the vertical pipe positioning and clamping mechanism 5 are respectively assembled with the assembly holes 2-2 on the rectangular frame 2-1 in a detachable manner, the adjustment of the length direction can be realized through the cooperation with different assembly holes 2-2 on the rectangular frame 2-1 so as to match the structural dimension of the length direction of a workpiece, the upper and lower pipe pneumatic positioning and clamping assemblies capable of realizing the angle and the upper and lower position adjustment are arranged in the upper and lower pipe positioning and clamping mechanisms 4 so as to realize the cooperation with different types of bicycle frames, the vertical pipe positioning and clamping mechanism 5 is provided with a vertical pipe upper pneumatic compression assembly and a vertical pipe positioning and clamping assembly, the five-way pipe positioning and clamping mechanism 6 is arranged at the lower part of the vertical pipe positioning and clamping mechanism 6, the five-way pipe positioning and clamping mechanism 4 is welded with the upper and lower pipe positioning and clamping mechanism 6 before the bicycle frame 1 is operated, the components of the front triangle part 1 of the bicycle frame are positioned and locked.

Referring to fig. 2, the pneumatic positioning and clamping fixture for welding the front triangle part of the bicycle frame comprises a head pipe positioning and clamping mechanism 3, wherein a head pipe pneumatic positioning and clamping assembly comprises a head pipe positioning block 3-2, an adjustable connecting seat 3-3 and a head pipe clamping cylinder 3-1, the head pipe positioning block 3-2 is vertically arranged in two groups, a V-shaped positioning groove is formed in each group of head pipe positioning blocks 3-2, a supporting plate for limiting the height position of a head pipe is arranged at the bottom of the lower group of head pipe positioning blocks, and a telescopic arm of the head pipe clamping cylinder 3-1 is connected with the head pipe positioning block 3-2 through the adjustable connecting seat 3-3.

Referring to fig. 3 and 4, the pneumatic positioning and clamping fixture for welding the front triangle part of the bicycle frame is characterized in that an upper pipe positioning and clamping mechanism 4 and a lower pipe positioning and clamping mechanism 4 of the pneumatic positioning and clamping fixture are further provided with an L-shaped support 4-1, two ends of a horizontal arm of the L-shaped support 4-1 are assembled with a rectangular frame 2-1 of a base 2 through a support plate 4-2, a horizontal chute 4-2-1 is arranged on the support plate 4-2, stepless adjustment of the L-shaped support 4-1 in the left-right direction can be achieved through the horizontal chute 4-2-1 so as to be more widely suitable for the change of the length dimension of the bicycle frame part 1, the vertical chute 4-1-1 is arranged on a vertical arm of the L-shaped support 4-1, the pneumatic positioning and clamping assembly for the upper pipe and the lower pipe comprises two parts which are arranged up and down, an upper pipe positioning unit and a lower pipe compressing unit are arranged in each part, an upper pipe 1-2, a lower pipe 1-5 of the front triangle part 1 of the bicycle frame is clamped and fixed through the upper pipe positioning unit and the lower pipe compressing unit, and the upper pipe compressing unit and the lower pipe compressing unit, and the upper pipe positioning unit and the lower pipe compressing unit can be matched with the vertical chute 4-1, and the height dimension of the vertical support 4-1 can be matched with the height dimension of the bicycle frame 1.

Referring to fig. 3, 4 and 5, the front triangle part welding pneumatic positioning and clamping tool for the bicycle frame disclosed by the utility model comprises an upper tube positioning unit and a lower tube positioning unit of an upper tube positioning and clamping mechanism 4, wherein the upper tube positioning unit and the lower tube positioning and clamping mechanism 4 comprise a positioning block 4-6 and a positioning seat 4-7, the positioning seat 4-7 is of a T-shaped seat structure, a stud 4-9 is arranged at the tail part of the positioning seat, the stud 4-9 passes through a vertical chute 4-1-1 of an L-shaped support 4-1 and then is fixed through a fixing block 4-8 and a locking nut 4-10, the upper tube 1-2 or the lower tube 1-5 can be adjusted by sliding the positioning seat 4-7 up and down in the vertical chute 4-1-1 of the L-shaped support 4-1, the positioning block 4-6 is arranged at two ends of the head part of the positioning seat 4-7, and an arc positioning groove matched with the outer surface of the upper tube workpiece and the lower tube workpiece is arranged on the positioning block 4-6.

Referring to fig. 3, 4 and 6, the front triangle part welding pneumatic positioning and clamping tool of the bicycle frame of the utility model comprises an upper pipe pressing unit and a lower pipe pressing unit of an upper pipe positioning and clamping mechanism 4, wherein the upper pipe pressing unit and the lower pipe pressing unit comprise a pressing seat 4-3, a rotary cylinder 4-4 and an upper pipe pressing head and a lower pipe pressing head 4-5, a stud 4-9 is arranged at the tail part of the pressing seat 4-3, the stud 4-9 passes through a vertical chute 4-1 of an L-shaped support 4-1 and then is fixed through a fixed block 4-8 and a locking nut 4-10, the rotary cylinder 4-4 is arranged at the head part of the pressing seat 4-3, and the upper pipe pressing head 4-5 and the lower pipe pressing head 4-5 are arranged on a rotary telescopic arm of the rotary cylinder 4-4.

Referring to fig. 2, 7 and 8, the welding pneumatic positioning and clamping tool for the front triangular part of the bicycle frame is characterized in that a U-shaped support 5-4 is further arranged on a vertical arm of the front triangular part of the bicycle frame, the heights of two vertical arms of the U-shaped support 5-4 are different, the front side is low, the rear side is high, a vertical pipe upper pneumatic pressing component and a vertical pipe positioning component are installed on the vertical arm of the rear side of the U-shaped support 5-4, the vertical pipe upper pneumatic pressing component comprises a vertical pipe pressing cylinder 5-1 and a vertical pipe pressing head 5-2, the vertical pipe pressing cylinder 5-1 is vertically arranged, the telescopic arms of the vertical pipe pressing cylinder 5-1 move up and down, the vertical pipe pressing head 5-2 is installed on the telescopic arm of the vertical pipe pressing cylinder 5-1, when the telescopic arm of the vertical pipe pressing cylinder 5-1 stretches out, the vertical pipe pressing head 5-2 presses the upper end of the vertical pipe 1-3, the vertical pipe positioning component 5-3 comprises two parts which are arranged up and down, arc-shaped positioning grooves matched with the outer surfaces of the vertical pipes 1-3 in the front triangular part 1 of the bicycle frame are arranged in each part, and the front and rear sides of the vertical pipe can be limited by the arc-shaped positioning grooves 1-3.

Still referring to fig. 2, 7 and 8, the pneumatic positioning and clamping tool for welding the front triangle part of the bicycle frame disclosed by the utility model is characterized in that a five-way pipe pneumatic positioning and clamping assembly in a five-way pipe positioning and clamping mechanism 6 comprises a five-way pipe compressing cylinder 6-1 and a five-way pipe pressing head 6-2, wherein the five-way pipe compressing cylinder 6-1 is arranged on a front vertical arm of a U-shaped support 5-4 of a vertical pipe positioning and clamping mechanism 5, two groups of the five-way pipe pressing heads 6-2 are oppositely arranged front and back, one group of the five-way pipe pressing heads 6-2 is fixedly arranged on the lower part of a rear vertical arm of the U-shaped support 5-4 of the vertical pipe positioning and clamping mechanism 5, the other group of the five-way pipe pressing heads are arranged on a telescopic arm of the five-way pipe compressing cylinder 6-1, and when the telescopic arm of the five-way pipe compressing cylinder 6-1 stretches out, two ends of the five-way pipe 1-4 are compressed and fixed through the two groups of the five-way pipe pressing heads 6-2 which are oppositely arranged front and back.

Still referring to fig. 2, 7 and 8, the pneumatic positioning and clamping fixture for welding the front triangle part of the bicycle frame is further provided with a set of cylinder action control handles 7, and the cylinder action control handles 7 are arranged on the front vertical face of the rectangular frame 2-1 of the base 2.

Referring to fig. 1 to 8, when the welding operation of the front triangle part of the bicycle frame is carried out by adopting the utility model, firstly, the positions and the spatial postures of the head pipe positioning and clamping mechanism 3, the upper pipe positioning and clamping mechanism 4, the vertical pipe positioning and clamping mechanism 5 and the five-way pipe positioning and clamping mechanism 6 are adjusted according to the structural size of the front triangle part 1 of the bicycle frame of the batch, then the head pipe 1-1, the upper pipe 1-2, the lower pipe 1-5, the vertical pipe 1-3 and the five-way pipe 1-4 are respectively positioned by corresponding positioning structures, the combined sizes of the components are rechecked to be matched with the size of a welded workpiece, and the cylinders in the head pipe positioning and clamping mechanism 3, the upper pipe and lower pipe positioning and clamping mechanism 4, the vertical pipe positioning and clamping mechanism 5 and the five-way pipe positioning and clamping mechanism 6 are actuated by operating the cylinder actuating control handle 7, so that the components are clamped and fixed, and after the operation is finished, the welding operation is carried out on the workpiece by using welding equipment and tools.

Claims (9)

1. A front triangle part welding pneumatic positioning and clamping tool of a bicycle frame is characterized by comprising a base (2), a head pipe positioning and clamping mechanism (3), an upper pipe positioning and clamping mechanism (4), a lower pipe positioning and clamping mechanism (5) and a five-way pipe positioning and clamping mechanism (6), wherein the base (2) is provided with a workbench of a rectangular frame structure, the workbench is fixed on the horizontal ground, a plurality of groups of assembly holes (2-2) are formed in two long sides of the rectangular frame (2-1), the head pipe positioning and clamping mechanism (3) is arranged on the short side of the rectangular frame (2-1) and is provided with a head pipe pneumatic positioning and clamping assembly capable of being adjusted in the upper and lower positions, the upper pipe positioning and clamping mechanism (4) and the vertical pipe positioning and clamping mechanism (5) are respectively assembled with the assembly holes (2-2) in the rectangular frame (2-1) in a detachable mode, an upper pipe pneumatic positioning and clamping assembly capable of realizing angle adjustment and a lower pipe pneumatic positioning and clamping assembly capable of being adjusted in the upper and lower positions are arranged in the vertical pipe positioning and clamping mechanism (5), and the five-way pipe positioning and clamping mechanism (6) is provided with a five-way positioning and clamping mechanism clamping assembly.

2. The pneumatic positioning and clamping tool for welding the front triangle part of the bicycle frame according to claim 1 is characterized in that the upper and lower pipe positioning and clamping mechanism (4) is further provided with an L-shaped support (4-1), two ends of a horizontal arm of the L-shaped support (4-1) are assembled with a rectangular frame (2-1) of the base (2) through a support plate (4-2), a horizontal chute (4-2-1) is arranged on the support plate (4-2), a vertical chute (4-1-1) is arranged on a vertical arm of the L-shaped support (4-1), the upper and lower pipe pneumatic positioning and clamping assembly comprises two parts which are arranged up and down, an upper and lower pipe positioning unit and an upper and lower pipe pressing unit are arranged in each part, and the upper and lower pipe positioning unit and the upper and lower pipe pressing unit are assembled with the vertical chute (4-1-1) of the L-shaped support (4-1).

3. The welding pneumatic positioning and clamping tool for the front triangle part of the bicycle frame, which is disclosed in claim 2, is characterized in that the upper and lower tube positioning units comprise positioning blocks (4-6) and positioning seats (4-7), the positioning seats (4-7) are of T-shaped seat structures, studs (4-9) are arranged at the tail parts of the positioning seats, the studs (4-9) penetrate through vertical sliding grooves (4-1) of the L-shaped support (4-1) and then are fixed through fixing blocks (4-8) and locking nuts (4-10), the positioning blocks (4-6) are arranged at two ends of the head parts of the positioning seats (4-7), and arc-shaped positioning grooves matched with the outer surfaces of the upper and lower tube workpieces are formed in the positioning blocks (4-6).

4. The welding pneumatic positioning and clamping tool for the front triangle part of the bicycle frame according to claim 3 is characterized in that the upper pipe pressing unit and the lower pipe pressing unit comprise a pressing seat (4-3), a rotary cylinder (4-4) and an upper pipe pressing head and a lower pipe pressing head (4-5), a stud (4-9) is arranged at the tail of the pressing seat (4-3), the stud (4-9) penetrates through a vertical chute (4-1) of an L-shaped support (4-1) and then is fixed through a fixing block (4-8) and a locking nut (4-10), the rotary cylinder (4-4) is mounted at the head of the pressing seat (4-3), and the upper pipe pressing head and the lower pipe pressing head (4-5) are mounted on a rotary telescopic arm of the rotary cylinder (4-4).

5. The welding pneumatic positioning and clamping tool for the front triangle part of the bicycle frame, which is disclosed in claim 4, is characterized in that the head pipe pneumatic positioning and clamping assembly in the head pipe positioning and clamping mechanism (3) comprises a head pipe positioning block (3-2), an adjustable connecting seat (3-3) and a head pipe clamping cylinder (3-1), wherein the head pipe positioning block (3-2) is vertically arranged in two groups, each group of head pipe positioning blocks (3-2) is provided with a V-shaped positioning groove, the bottom of the lower group of head pipe positioning blocks is provided with a supporting plate for limiting the height position of the head pipe (1-1), and a telescopic arm of the head pipe clamping cylinder (3-1) is connected with the head pipe positioning block (3-2) through the adjustable connecting seat (3-3).

6. The welding pneumatic positioning and clamping tool for the front triangle part of the bicycle frame according to claim 4, wherein the vertical pipe positioning and clamping mechanism (5) is further provided with a U-shaped support (5-4), the two vertical arms of the U-shaped support (5-4) are different in height and are in a front low-back high state, the vertical pipe upper end pneumatic pressing component and the vertical pipe positioning component are installed on the vertical arm behind the U-shaped support (5-4), the vertical pipe upper end pneumatic pressing component comprises a vertical pipe pressing cylinder (5-1) and a vertical pipe pressing head (5-2), the vertical pipe pressing cylinder (5-1) is vertically arranged, the telescopic arms of the vertical pipe pressing cylinder (5-1) move up and down, and the vertical pipe pressing head (5-2) is installed on the telescopic arms of the vertical pipe pressing cylinder (5-1).

7. The pneumatic positioning and clamping fixture for welding the front triangle of the bicycle frame, as set forth in claim 6, characterized in that the vertical pipe positioning assembly (5-3) comprises two parts which are arranged up and down, and each part is provided with an arc-shaped positioning groove matched with the outer surface of the neutral pipe (1-3) of the front triangle (1) of the bicycle frame.

8. The pneumatic positioning and clamping tool for welding the front triangle part of the bicycle frame, which is characterized in that a five-way pipe pneumatic positioning and clamping assembly in the five-way pipe positioning and clamping mechanism (6) comprises a five-way pipe compressing cylinder (6-1) and a five-way pipe pressing head (6-2), the five-way pipe compressing cylinder (6-1) is arranged on a front vertical arm of a U-shaped support (5-4) of a vertical pipe positioning and clamping mechanism (5), and two groups of the five-way pipe pressing heads (6-2) are oppositely arranged front and back, one group of the two groups of the five-way pipe pressing heads is fixedly arranged on the lower part of a rear vertical arm of the U-shaped support (5-4) of the vertical pipe positioning and clamping mechanism (5), and the other group of the five-way pipe pressing cylinders are arranged on telescopic arms of the five-way pipe compressing cylinder (6-1).

9. The bicycle frame front triangle part welding pneumatic positioning clamping fixture as claimed in any one of claims 5 to 8, wherein a set of cylinder action control handles (7) is further provided, and the cylinder action control handles (7) are arranged on the front elevation of the rectangular frame (2-1) of the base (2).