CN113478146A

CN113478146A - Main shaft welding jig and turning arm locating component thereof

Info

Publication number: CN113478146A
Application number: CN202110727763.6A
Authority: CN
Inventors: 黄欣; 李戎; 张银
Original assignee: Siemens Switchgear Ltd
Current assignee: Siemens Switchgear Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2021-10-08
Anticipated expiration: 2041-06-29
Also published as: CN113478146B

Abstract

A crank arm positioning assembly of a spindle welding jig includes a support member (20), a first fastener (30), and a second fastener (40). The first fastener is fixedly connected with the support piece. The first fastening member has two first fastening surfaces (31). The two first fastening faces are arranged perpendicularly to the first direction (D1) and are oriented oppositely. The second fastener is movably connected to the support along a plane perpendicular to the first direction. The second fastening member has two second fastening surfaces (41). The second fastening surface is disposed obliquely with respect to a plane perpendicular to the first direction. The second fastener is movable from a release position to a clamping position. Each second fastening surface opposes one first fastening surface in the first direction when in the clamping position. During the movement of the second fastening member from the release position to the clamping position, the minimum clearance between the second fastening surface and the first fastening surface in the first direction gradually decreases. The crank arm positioning assembly is high in positioning accuracy. A spindle welding jig is also provided.

Description

Main shaft welding jig and turning arm locating component thereof

Technical Field

The invention relates to a positioning assembly, in particular to a positioning assembly for positioning a crank arm in a spindle welding process and a spindle welding fixture comprising the same.

Background

When the circuit breaker is produced, the crank arm needs to be welded to the main shaft, and the relative positions of the main shaft and the crank arm need to be fixed in an assisting mode through the crank arm positioning assembly in the process. The current crank arm positioning component is easy to generate positioning deviation and affects the welding quality.

Disclosure of Invention

The invention aims to provide a crank arm positioning assembly of a spindle welding fixture, which is high in positioning precision.

The invention also aims to provide a spindle welding fixture, which has higher positioning precision of the crank arm positioning component.

The invention provides a crank arm positioning assembly of a spindle welding fixture, which is used for positioning a crank arm and comprises a supporting piece, a first fastening piece and a second fastening piece. The first fastener is fixedly connected with the support piece. The first fastening member has two first fastening surfaces. The two first fastening surfaces are arranged perpendicular to a first direction and face opposite directions. The second fastener is movably connected to the support along a plane perpendicular to the first direction. The second fastening member has two second fastening surfaces. The second fastening surface is disposed obliquely with respect to a plane perpendicular to the first direction. The second fastener is movable from a release position to a clamping position. Each of the second fastening surfaces opposes one of the first fastening surfaces in the first direction with the second fastening member in the clamping position. During the process that the second fastening piece moves from the releasing position to the clamping position, the minimum gap between the second fastening surface and the first fastening surface along the first direction is gradually reduced so as to clamp the crank arm between the first fastening surface and the second fastening surface.

The crank arm positioning assembly of the spindle welding fixture can enable the first fastening surface and the second fastening surface to gradually clamp the crank arm through the movement of the second fastening piece, so that the crank arm is tightly abutted to the first fastening surface in parallel, and the positioning accuracy of the crank arm is improved.

In yet another exemplary embodiment of a crank arm positioning assembly of a spindle welding fixture, a first fastener includes a clamp plate portion. Two first fastening faces set up in splint portion and set up mutually back on the back. The second fastener comprises two second clamping arms distributed along the first direction. Each second clamping arm is provided with a second fastening surface. The two second fastening surfaces are oppositely arranged along the first direction. With the second fastener in the clamping position, the clamp plate portion is inserted between the two second clamp arms. The structure is simple and convenient to process.

In another exemplary embodiment of a crank arm positioning assembly of a spindle welding fixture, a first fastener includes two first clamp arms distributed in a first direction. Each first clip arm has a first fastening surface. The two first fastening surfaces are oppositely arranged. The second fastener includes an insert portion. The two second fastening surfaces are arranged on the insertion part and are arranged along the first direction in an opposite mode. With the second fastener in the clamped position, the insert is inserted between the two first clip arms. The structure is simple and convenient to process.

In yet another exemplary embodiment of the crank arm positioning assembly of the spindle welding jig, the crank arm positioning assembly further comprises a tightening cylinder and a connecting rod. The supporting piece is fixedly connected with a cylinder body of the fastening hydraulic cylinder. The piston rod of the tightening cylinder is movable in a direction perpendicular to the first direction. The second fastening member is rotatably connected to a piston rod of the fastening cylinder about an axis parallel to the first direction. One end of the connecting rod is rotatably connected with the supporting piece around an axis parallel to the first direction, and the other end of the connecting rod is rotatably connected with the second fastening piece around an axis parallel to the first direction. The tightening cylinder is operable to drive the second fastener between the release position and the clamping position. The movement of the second fastener is conveniently controlled by tightening the hydraulic cylinder and the link, thereby facilitating operation.

In yet another exemplary embodiment of the crank arm positioning assembly of the spindle welding jig, the crank arm positioning assembly further comprises a connecting pin. The connecting pin can penetrate through the first fastener and the crank arm along the first direction. The connecting pin includes a main body portion and a plurality of mating portions. The main body portion is cylindrical extending in a first direction. The matching part is convexly arranged on the main body part and is in a ring shape extending along the circumferential direction of the main body part. The mating portion can form an interference fit with the first fastener and the crank arm to fix a relative position of the first fastener and the crank arm in a direction perpendicular to the first direction. The plurality of matching parts are arranged at intervals along the first direction. Whereby the relative position of the first fastener and the crank arm in a direction perpendicular to the first direction can be fixed.

In yet another exemplary embodiment of the crank arm positioning assembly of the spindle welding jig, the connecting pin further comprises a ball plunger and a stop. The ball plunger is embedded in one end of the main body part. The stopping part is arranged at the other end of the main body part. The stopping part is cylindrical and has a diameter larger than that of the main body part, and the stopping part is coaxial with the main body part. Thereby preventing the connecting pin from falling off during the welding process.

The invention also provides a spindle welding fixture which comprises the crank arm positioning assembly. The crank arm positioning assembly of the spindle welding fixture can enable the first fastening surface and the second fastening surface to gradually clamp the crank arm through the movement of the second fastening piece, so that the crank arm is tightly abutted to the first fastening surface in parallel, and the positioning accuracy of the crank arm is improved.

In another exemplary embodiment of the spindle welding jig, the spindle welding jig further includes a base, two lifting hydraulic cylinders, and two brackets. The lifting hydraulic cylinder is arranged on the base. The piston rod of the lifting cylinder is movable in a second direction and in the opposite direction to the second direction, wherein the second direction is perpendicular to the first direction. Each bracket is connected with a piston rod of a lifting hydraulic cylinder. The bracket has a groove extending in a first direction and extending therethrough. The groove walls of the groove can abut against the spindle in the second direction and can prevent the spindle from moving relative to the carrier in a third direction and a direction opposite to the third direction, wherein the third direction is perpendicular to the first direction and the second direction. When welding is finished, the main shaft can be separated along the second direction through the action of the lifting hydraulic cylinder.

In yet another exemplary embodiment of the spindle welding fixture, the crank arm positioning assembly further comprises a tightening cylinder. The supporting piece is fixedly connected with a cylinder body of the fastening hydraulic cylinder. And a piston rod of the fastening hydraulic cylinder is connected with a second fastening piece. The tightening cylinder is operable to drive the second fastener between the release position and the clamping position. The fastening hydraulic cylinder is arranged on the base. The base has a hydraulic fitting. A channel for communicating the hydraulic connector with the lifting hydraulic cylinder and fastening a hydraulic interface of the hydraulic cylinder is arranged in the base. Thereby making the overall structure more compact.

In a further exemplary embodiment of the spindle welding jig, the spindle welding jig further comprises two end fixtures. The end fixing piece is arranged on the base. The two end fixing pieces are respectively used for fixing two ends of the main shaft. Thereby facilitating the fixing of the main shaft.

In yet another exemplary embodiment of the spindle welding jig, the spindle welding jig further comprises a plurality of spray heads. The shower nozzle sets up in the base, and the shower nozzle is used for spraying the liquid of preventing splashing. Therefore, the spraying of the splashing liquid is prevented during welding, and the weld joint is convenient to clean after welding.

Drawings

The following drawings are only schematic illustrations and explanations of the present invention, and do not limit the scope of the present invention.

FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a crank arm positioning assembly of a spindle welding fixture.

Fig. 2 and 3 are schematic structural views for explaining a changed state of the crank arm positioning assembly shown in fig. 1.

Fig. 4 is a partial schematic structural view of the crank arm positioning assembly shown in fig. 1.

Fig. 5 is a schematic structural view of the connecting pin.

Fig. 6 is a schematic structural view for explaining another exemplary embodiment of the crank arm positioning assembly.

Fig. 7 is a partial schematic structural view of the crank arm positioning assembly shown in fig. 6.

Fig. 8 is a schematic structural view for explaining an exemplary embodiment of a spindle welding jig.

Description of the reference symbols

10 crank arm positioning assembly

20 support member

30 first fastener

31 first fastening surface

32 first clamping arm

33 clamping plate part

40 second fastener

41 second fastening surface

42 insertion part

43 second arm

50 fastening hydraulic cylinder

51 fastening piston rod of hydraulic cylinder

60 connecting rod

70 connecting pin

71 body part

72 mating part

73 ball plunger

74 stop

80 base

81 hydraulic joint

91 lifting hydraulic cylinder

92 bracket

93 groove

94 end fixing piece

95 shower nozzle

100 spindle

200 crank arm

D1 first direction

D2 second direction

Third direction D3

Detailed Description

In order to more clearly understand the technical features, objects and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals indicate the same or structurally similar but functionally identical elements.

"exemplary" means "serving as an example, instance, or illustration" herein, and any illustration, embodiment, or steps described as "exemplary" herein should not be construed as a preferred or advantageous alternative.

In this document, "first", "second", etc. do not mean their importance or order, etc., but merely mean that they are distinguished from each other so as to facilitate the description of the document.

For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product.

FIG. 1 is a schematic diagram illustrating an exemplary embodiment of a crank arm positioning assembly of a spindle welding fixture. As shown in fig. 1, the spindle 100 has been fixed by other structures and is axially parallel to the first direction D1, and the crank arm positioning assembly 10 is used to fix the crank arm 200. The crank arm positioning assembly 10 includes a support member 20, a first fastener 30, a second fastener 40, a fastening cylinder 50 and a link 60.

The first fastening member 30 is fixedly coupled to the support member 20. The support 20 is fixedly connected to a cylinder body of the fastening hydraulic cylinder 50. The piston rod 51 of the tightening cylinder 50 is movable in a third direction D3 and in a direction opposite to the third direction D3, wherein the third direction D3 is perpendicular to the first direction D1. The second fastening member 40 is rotatably connected to the piston rod 51 of the fastening hydraulic cylinder 50 about an axis parallel to the first direction D1. The link 60 has one end rotatably connected to the supporter 20 about an axis parallel to the first direction D1 and the other end rotatably connected to the second fastener 40 about an axis parallel to the first direction D1. The tightening cylinder 50 is operable to drive the second tightening member 40 between a release position and a clamping position along a plane perpendicular to the first direction D1. Fig. 2 and 3 are schematic structural views for explaining a changed state of the crank arm positioning assembly shown in fig. 1. The second fastener 40 is in a clamped position in fig. 1 and 2, and the second fastener 40 is in a released position in fig. 3.

Fig. 4 is a partial schematic view of the crank arm positioning assembly of fig. 1 with the second fastener 40 in a clamped position. As shown in fig. 4, in the present exemplary embodiment, the first fastening member 30 includes one clamping plate portion 33. The clamping plate portion 33 has two first fastening surfaces 31. Both first fastening surfaces 31 are perpendicular to the first direction D1 and are arranged opposite each other. The second fastener 40 includes two second clamping arms 43 distributed along the first direction D1. Each second clip arm 43 has a second fastening surface 41, and the second fastening surfaces 41 are disposed obliquely with respect to a plane perpendicular to the first direction D1, as an exemplary illustration, the distance between two second fastening surfaces 41 is gradually increased along a direction from bottom to top in fig. 4, or it can be understood that the distance between one second fastening surface 41 and its corresponding first fastening surface 31 is gradually increased along a direction from bottom to top in fig. 4. As another exemplary illustration, it can be seen from fig. 4 that the two second fastening surfaces 41 are two sides of a U-shaped groove, which gradually increases from the bottom upwards. The two second fastening surfaces 41 are oppositely arranged along the first direction D1. With reference to fig. 2 and 4, with the second fastening member 40 in the clamping position, the clamping plate portion 33 is inserted between the two second clamping arms 43, and each second fastening surface 41 is opposed to one first fastening surface 31 in the first direction D1. Referring to fig. 3 and 4, when the second fastening member 40 is located at the release position, the clamping plate portion 33 is not located between the two second clamping arms 43, and the first fastening surface 31 and the second fastening surface 41 are offset from each other along the first direction D1. During the movement of the second fastening member 40 from the releasing position to the clamping position, the minimum gap between the second fastening surface 41 and the first fastening surface 31 along the first direction D1 is gradually reduced to clamp the crank arm 200 between the first fastening surface 31 and the second fastening surface 41.

The crank arm positioning component of the spindle welding fixture can enable the first fastening surface 31 and the second fastening surface 41 to gradually clamp the crank arm 200 through the movement of the second fastening piece 40, so that the crank arm 200 is abutted against the first fastening surface 31 in parallel, and the positioning accuracy of the crank arm is improved.

The crank arm positioning assembly of the spindle welding jig can conveniently control the movement of the second fastening member 40 by fastening the hydraulic cylinder 50 and the connecting rod 60, thereby facilitating the operation. But is not limited to such, and in other exemplary embodiments, the second fastener 40 may be driven in motion by other structures.

As shown in FIG. 1, in the illustrated embodiment, the crank arm positioning assembly 10 further includes a connecting pin 70. The connecting pin 70 can be inserted through the first fastener 30 and the crank arm 200 in the first direction D1. Fig. 5 is a schematic structural view of the connecting pin. As shown in fig. 5, the connecting pin 70 includes a main body portion 71 and a plurality of engaging portions 72, and fig. 5 shows two engaging portions 72, and the number of the engaging portions 72 may be set according to actual needs, and is not limited herein. The body portion 71 has a cylindrical shape extending in the first direction D1. The engaging portion 72 is provided to protrude from the main body portion 71 and has an annular shape extending in the circumferential direction of the main body portion 71. The mating portion 72 can form an interference fit with the first fastener 30 and the crank arm 200 to fix the relative positions of the first fastener 30 and the crank arm 200 in a direction perpendicular to the first direction D1. The two engagement portions 72 are spaced apart in the first direction D1. Such an arrangement may facilitate installation and removal of the connecting pin. More specifically, since the fitting portions 72 are provided at intervals, it is more convenient in the process of removing the connecting pin 70 than in the case where the fitting portions 72 are provided integrally.

As shown in fig. 5, in the present exemplary embodiment, the connecting pin 70 further includes a ball plunger 73 and a stopper 74. Among these, ball plungers are also known as spring plungers, or positioning beads/posts. The ball plunger 73 is fitted to one end of the body portion 71. The stopper 74 is provided at the other end of the main body 71. The stopper portion 74 has a cylindrical shape coaxially disposed with the main body portion 71 and has a diameter larger than that of the main body portion 71. In use, the ball plungers 73 and the stoppers 74 are respectively located at both ends of the connecting pin 70, which penetrate through the first fastening member 30 and the crank arm 200, thereby preventing the connecting pin from falling off during welding.

Fig. 6 is a schematic structural view for explaining another exemplary embodiment of the crank arm positioning assembly. Fig. 7 is a partial schematic structural view of the crank arm positioning assembly shown in fig. 6. The crank arm positioning assembly of the present exemplary embodiment is the same as or similar to the crank arm positioning assembly shown in fig. 1, and is not described herein again, except for the structure of the first and

second fastening members

30 and 40. In fig. 6 and 7, the second fastener 40 is in the clamped position. As shown in fig. 6 and 7, in the present exemplary embodiment, the first fastener 30 includes two first clamping arms 32 distributed along a first direction D1. Each first clip arm 32 has a first fastening surface 31. Both first fastening surfaces 31 are perpendicular to the first direction D1 and are oppositely disposed. The second fastener 40 includes an insert 42. The insertion portion 42 has two second fastening surfaces 41. The second fastening surfaces 41 are disposed obliquely with respect to a plane perpendicular to the first direction D1, and as an exemplary illustration, the distance between two second fastening surfaces 41 is gradually reduced from bottom to top in fig. 7, or it can be understood that the distance between one second fastening surface 41 and its corresponding first fastening surface 31 is gradually reduced from bottom to top in fig. 7. The two second fastening surfaces 41 are arranged opposite each other in the first direction D1. With the second fastening member 40 in the clamping position, the insertion portion 42 is inserted between the two first clamping arms 32, and each second fastening surface 41 is opposed to one first fastening surface 31 in the first direction D1. During the movement of the second fastening member 40 from the releasing position to the clamping position, the minimum gap between the second fastening surface 41 and the first fastening surface 31 along the first direction D1 is gradually reduced to clamp the crank arm 200 between the first fastening surface 31 and the second fastening surface 41.

Alternatively, the crank arm positioning assembly shown in fig. 1 and the crank arm positioning assembly shown in fig. 6 may be selected according to the weld position, and specifically, the second fastening surface 41 and the weld are located on the same side of the crank arm 200 by selecting the crank arm positioning assembly. Since the weld is shrunk when the welding is completed, in the case where the weld is located on the same side of the crank arm 200 as the second fastening surface 41, the deformation caused by the shrinkage of the weld can be prevented by the clamping force exerted on the crank arm 200 by the second fastening surface 41, thereby improving the welding quality.

The invention also provides a spindle welding fixture, and fig. 8 is a schematic structural diagram for explaining an exemplary embodiment of the spindle welding fixture. As shown in fig. 8, the spindle welding jig includes a base 80, a crank arm positioning assembly 10 shown in fig. 1 (the crank arm positioning assembly 10 on the right side), a crank arm positioning assembly 10 shown in fig. 6 (the crank arm positioning assembly 10 on the left side), and two end fixtures 94. The tightening cylinder 50 is provided to the base 80. End mounts 94 are provided on base 80. The two end fixtures 94 are used to fix both ends of the main shaft 100, respectively. For example, the tip holder 94 is provided at the top with a groove in which both ends of the main shaft 100 are placed to be fixed. The crank arm positioning component of the spindle welding fixture can enable the first fastening surface 31 and the second fastening surface 41 to gradually clamp the crank arm 200 through the movement of the second fastening piece 40, so that the crank arm 200 is abutted against the first fastening surface 31 in parallel, and the positioning accuracy of the crank arm is improved.

In other exemplary embodiments, the number of the crank arm positioning assemblies 10 can be adjusted as desired, and the crank arm positioning assemblies shown in fig. 1 or 6 can be used in part or in whole.

As shown in fig. 8, in the present exemplary embodiment, the spindle welding jig further includes two lifting hydraulic cylinders 91 and two brackets 92. The lifting cylinder 91 is provided to the base 80. The piston rod of the lifting cylinder 91 is movable in a second direction D2 and in a direction opposite to the second direction D2, wherein the second direction D2 is perpendicular to the first direction D1. Each bracket 92 is connected to the piston rod of a lifting cylinder 91. The bracket 92 has a groove 93 extending therethrough in a first direction D1. The walls of the groove 93 are able to abut against the main shaft 100 in the second direction D2 and to prevent the main shaft 100 from moving relative to the bracket 92 in a direction opposite to a third direction D3 and a third direction D3, wherein the third direction D3 is perpendicular to the first direction D1 and the second direction D2. When the welding is completed, the main shaft 100 may be disengaged in the second direction D2 by the action of the lifting hydraulic cylinder 91.

As shown in fig. 8, in the present exemplary embodiment, the base 80 has a hydraulic connection 81, and the hydraulic connection 81 is used for connecting an external hydraulic station. The external hydraulic station has, for example, a connection head which engages with the hydraulic connector 81, has, for example, a handle which is easy to handle and can be fastened to the hydraulic connector 81, in particular by means of an aircraft plug, and can also provide hydraulic pressure for other spindle welding fixtures. The base 80 is provided with a passage inside which the hydraulic connections of the hydraulic connector 81 and the lifting cylinder 91 and the tightening cylinder 50 are connected. Thereby making the overall structure more compact.

As shown in fig. 8, in the present exemplary embodiment, the spindle welding jig further includes a plurality of spray heads 95. The nozzle 95 is disposed on the base 80, and the nozzle 95 is used for spraying the anti-splashing liquid. Therefore, the spraying of the splashing liquid is prevented during welding, and the weld joint is convenient to clean after welding.

It should be understood that although the present description has been described in terms of various embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and those skilled in the art will recognize that the embodiments described herein may be combined as suitable to form other embodiments, as will be appreciated by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications such as combinations, divisions or repetitions of features, which do not depart from the technical spirit of the present invention, should be included in the scope of the present invention.

Claims

1. Spindle welding jig's crank arm locating component, crank arm locating component is used for location crank arm (200), its characterized in that includes:

a support (20);

-a first fastening member (30) fixedly connected to said support (20), said first fastening member (30) having two first fastening faces (31), both said first fastening faces (31) being arranged perpendicularly to a first direction (D1) and facing oppositely; and

-a second fastening member (40) movably connected to said support (20) along a plane perpendicular to said first direction (D1), said second fastening member (40) having two second fastening faces (41), said second fastening faces (41) being arranged obliquely with respect to the plane perpendicular to said first direction (D1);

said second fastener (40) being movable from a release position to a clamping position; each of the second fastening surfaces (41) is opposed to one of the first fastening surfaces (31) in the first direction (D1) with the second fastening member (40) in the clamped position; during the movement of the second fastening member (40) from the release position to the clamping position, the minimum clearance between the second fastening surface (41) and the first fastening surface (31) in the first direction (D1) is gradually reduced to clamp the crank arm (200) between the first fastening surface (31) and the second fastening surface (41).

2. Crank arm positioning assembly according to claim 1, characterized in that the first fastening member (30) comprises a clamping plate (33), the two first fastening surfaces (31) being arranged opposite each other on the clamping plate (33); the second fastening member (40) comprises two second clamping arms (43) distributed along the first direction (D1), each second clamping arm (43) is provided with one second fastening surface (41), and the two second fastening surfaces (41) are oppositely arranged along the first direction (D1); with the second fastener (40) in the clamping position, the clip plate portion (33) is inserted between the two second clip arms (43).

3. A crank arm positioning assembly according to claim 1, characterized in that said first fastening member (30) comprises two first clamping arms (32) distributed along said first direction (D1), each of said first clamping arms (32) having one of said first fastening surfaces (31), said two first fastening surfaces (31) being disposed opposite each other; the second fastening member (40) comprises an insertion portion (42), two second fastening surfaces (41) being arranged on the insertion portion (42) and facing away from each other along the first direction (D1); the insertion portion (42) is inserted between the two first clamp arms (32) with the second fastener (40) in the clamping position.

4. The crank arm positioning assembly of claim 1 further comprising:

-a tightening cylinder (50), the support (20) being fixedly connected to the cylinder body of the tightening cylinder (50), the piston rod of the tightening cylinder (50) being movable in a direction perpendicular to the first direction (D1), the second fastening member (40) being rotatably connected to the piston rod of the tightening cylinder (50) about an axis parallel to the first direction (D1); and

a link (60) having one end rotatably connected to the support (20) about an axis parallel to the first direction (D1) and the other end rotatably connected to the second fastener (40) about an axis parallel to the first direction (D1); the tightening cylinder (50) is operable to drive the second tightening member (40) between the release position and the clamping position.

5. The crank arm positioning assembly of claim 1 further comprising a connecting pin (70), wherein the connecting pin (70) is capable of being inserted through the first fastener (30) and the crank arm (200) in the first direction (D1), and wherein the connecting pin (70) comprises:

a main body portion (71) having a cylindrical shape extending in the first direction (D1), and

several cooperation portion (72), cooperation portion (72) protrusion set up in main part (71) just are along the ring shape of the circumference extension of main part (71), cooperation portion (72) can with first fastener (30) and crank arm (200) form interference fit, in order to fix first fastener (30) and crank arm (200) are along the perpendicular to the relative position of the direction of first direction (D1), several cooperation portion (72) are followed first direction (D1) interval sets up.

6. The crank arm positioning assembly of claim 5 wherein the connecting pin (70) further comprises:

a ball plunger (73) embedded in one end of the main body portion (71), and

a stop portion (74) arranged at the other end of the main body portion (71), wherein the stop portion (74) is cylindrical and is coaxial with the main body portion (71), and the diameter of the stop portion is larger than that of the main body portion (71).

7. Spindle welding jig comprising a crank arm positioning assembly according to any one of claims 1 to 6.

8. The spindle welding jig of claim 7, further comprising:

a base (80);

two lifting hydraulic cylinders (91) arranged on the base (80), wherein piston rods of the lifting hydraulic cylinders (91) can move along a second direction (D2) and the direction opposite to the second direction (D2), and the second direction (D2) is perpendicular to the first direction (D1); and

two brackets (92), each bracket (92) is connected with a piston rod of one lifting hydraulic cylinder (91), the brackets (92) are provided with a through groove (93) extending along the first direction (D1), the groove wall of the through groove (93) can abut against the main shaft (100) along the second direction (D2) and can prevent the main shaft (100) from moving relative to the brackets (92) along a third direction (D3) and the opposite direction of the third direction (D3), and the third direction (D3) is perpendicular to the first direction (D1) and the second direction (D2).

9. The spindle welding fixture of claim 8, wherein said crank arm positioning assembly further comprises a tightening cylinder (50), said support member (20) being fixedly attached to a cylinder of said tightening cylinder (50), a piston rod of said tightening cylinder (50) being attached to said second fastening member (40), said tightening cylinder (50) being operable to drive said second fastening member (40) between said release position and said clamping position, said tightening cylinder (50) being disposed on said base (80); the base (80) is provided with a hydraulic connector (81), and a channel which is communicated with hydraulic connectors of the hydraulic connector (81), the lifting hydraulic cylinder (91) and the fastening hydraulic cylinder (50) is arranged in the base (80).

10. The spindle welding jig of claim 8, further comprising two end fixtures (94), the end fixtures (94) being disposed on the base (80), the two end fixtures (94) being for fixing two ends of the spindle (100), respectively.

11. The spindle welding jig of claim 8, further comprising a plurality of spray heads (95), the spray heads (95) being disposed on the base (80), the spray heads (95) being configured to spray a splash-proof liquid.