A method for assembling sheet metal structure and a welding positioning tool applied thereto

Abstract

The application provides a sheet metal structure assembling method and a welding positioning tool applied in the method, and comprises the following steps: manufacturing an inner cylinder and an outer cylinder by sheet metal, positioning the inner cylinder, the outer cylinder and a support, adopting the same reference for the inner cylinder and the support; welding the support and the inner cylinder; positioning the flange of the outer cylinder and the support, welding the outer cylinder and the support; and welding the outer cylinder and the inner cylinder. The application has the advantages that: the sheet metal is formed into a motor cylinder body structure, the precision of the motor cylinder body can be ensured without subsequent finishing, and the production cost of the motor cylinder body is reduced; the welding operation is convenient, and the welding positioning is accurate and reliable.

Description

Technical Field

[0001] This invention relates to the field of motor housing assembly technology for water pumps, and in particular to an assembly method for sheet metal structures and a welding positioning fixture for its application. Background Technology

[0002] A water pump consists of a pump body and a motor. The motor drives an impeller within the pump body to transport water. For example, Chinese patent document CN115199554A, published on October 18, 2022, discloses a vertical multistage pipeline centrifugal pump. This application includes: inlet and outlet sections, water-lubricated bearings, guide vanes, a stamped impeller, a pump cover, a pump shaft, a tensioning screw, a coupling, a motor, a motor bracket, a tensioning component, a venting valve, a mechanical seal, a balance water pipe, and an outer cylinder. The inlet and outlet sections are cast, and the inlet and outlet flanges are located on the same straight line. The guide vanes are integrally cast from the guide vanes and the middle section. The pump cover is integrally cast from the final stage guide vanes and a separate pump cover. The stamped impeller is formed using stainless steel stamping and welding technology. However, the surface quality of the cast body in the prior art is poor, requiring precision machining, which increases material costs. For example, the precision machining device for casting motor base disclosed in CN112953146A on June 11, 2021 involves precision machining of the cast motor base, which involves complex equipment, cumbersome process and high production cost.

[0003] Furthermore, our company previously developed and disclosed a utility model patent for a canned pump and water supply system, authorized publication number CN213981230U. This patent discloses a first space formed by the enclosure between the outer walls of the pump's outer cylinder and the stator assembly. This first space, in conjunction with other passages, forms a first flow channel, thereby improving heat dissipation in the pump body's motor section. For pump bodies of this type, traditional casting is difficult; screw assembly makes it difficult to guarantee sealing, and bolts significantly increase the overall weight of the pump body, leading to a substantial increase in cost; while injection molding of plastic parts presents problems such as difficulty in ensuring roundness and easy deformation at corners and connections. All of the above-mentioned assembly methods for pump cylinders in existing technologies have shortcomings.

[0004] Because the positioning reference is difficult to control and the sealing is difficult to guarantee, there is no precedent in the existing technology for using sheet metal structures to make the motor cylinder of a water pump. Summary of the Invention

[0005] In view of the above-mentioned shortcomings of the prior art, the present invention provides a sheet metal structure assembly method and a welding positioning fixture for its application, which forms a sheet metal motor cylinder structure that can ensure the accuracy of the motor cylinder without subsequent precision machining and reduce the production cost of the motor cylinder.

[0006] To achieve the above objectives, the present invention adopts the following technical solution.

[0007] A method for assembling a sheet metal structure includes the following steps:

[0008] A. Sheet metal is used to fabricate the inner and outer cylinders, and the inner and outer cylinders and the bracket are positioned. The inner cylinder and the bracket use the same reference.

[0009] B. Welding brackets and inner cylinder;

[0010] C. Position the outer cylinder's flange to mate with the bracket, and weld the outer cylinder and bracket;

[0011] D. Weld the outer cylinder and the inner cylinder.

[0012] This application provides an assembly method for forming a double-layer motor cylinder by welding the inner cylinder, outer cylinder, and bracket together. This method can reduce the production cost of the motor cylinder and ensure the roundness and concentricity of the structure.

[0013] Preferably, the bracket is provided with positioning holes corresponding to the motor shaft. The positioning holes are coaxially arranged with the inner cylinder. In step A, the positioning of the inner cylinder and the bracket is achieved through the positioning holes and the positioning of the inner cylinder. The positioning holes correspond to the motor shaft, and the inner cylinder is used to fix the motor stator. The coaxial arrangement of the two can ensure the stability of the fit between the motor shaft and the motor stator, and avoid rotational misalignment. Thus, although it is a sheet metal assembly structure, the coaxiality and stability of the motor assembly can be ensured, improving the assembly efficiency of the water pump motor.

[0014] Preferably, the inner cylinder has an inwardly folded first flange at the end facing the support, which fits snugly against the support; the outer cylinder has an outwardly folded second flange at the end facing the support, and the support has a shoulder portion that mates with the second flange. In step C, the shoulder portion mates with the second flange for positioning. The mate between the second flange and the first flange is a special design for welding and assembling sheet metal parts. The second flange serves to position the inner cylinder against the support, and both the first and second flanges can be used as welding points, facilitating laser welding of the inner cylinder and the support, and the outer cylinder and the support.

[0015] Preferably, the inner cylinder has a third flange that folds outward at the end furthest from the support, and the outer cylinder has a fourth flange that folds inward at the end furthest from the support. The third flange and the fourth flange overlap, and in step D, the third flange and the fourth flange are welded together after they are fitted together. The setting of the third flange and the fourth flange can complete the reliable fitting and welding assembly of the rear ends of the inner cylinder and the outer cylinder.

[0016] Preferably, laser welding is used for welding in steps B, C, and D. This method ensures reliable welding, produces small weld points, and facilitates tooling positioning during welding.

[0017] A welding positioning fixture for the assembly method of the above-mentioned sheet metal structure includes a lower mold, on which positioning blocks and positioning shafts are provided. The positioning blocks are arranged in a circle, and the inner circumference of the positioning blocks matches the outer diameter of the outer cylinder. A pressure cap is provided at the end of the positioning shaft. A connecting shaft is provided at the axis of the lower mold. A mounting protrusion is fixed on the connecting shaft. An inner support block is provided on the mounting protrusion. A leveling frustum corresponding to the inner support block is provided on the connecting shaft. The inner support block and the leveling frustum cooperate through the frustum surface. The outer circumference of the inner support block cooperates with the inner side of the inner cylinder. A locking element corresponding to the connecting shaft is provided on the pressure cap. A positioning surface that cooperates with the bracket is provided on the pressure cap. Several clearance grooves for welding clearance are provided on the pressure cap and the lower mold respectively.

[0018] This application discloses a welding positioning fixture for a sheet metal sleeve. The inner support block and the pressure cap cooperate to clamp the positioning bracket and the inner cylinder. The outer cylinder leveling frustum cooperates with the positioning surface. When the pressure cap is locked, the inner support block is also pressed. Under the action of the positioning surface, it automatically levels and centers, and the structure is reliable. The positioning block positions the outer side of the outer cylinder and limits the position of the lower end of the outer cylinder, while the inner support block completes the positioning of the upper end of the inner cylinder. The combination and cooperation of each component, the axial positions of the pressure cap, the inner support block and the positioning block are all based on the axis of the connecting shaft. Therefore, the positioning of the inner cylinder, the outer cylinder and the bracket achieves the same axial reference. During welding, the fixture plays a reliable clamping and positioning role, ensuring the accuracy of the sheet metal welding positioning.

[0019] Preferably, the lower mold includes a base plate and a positioning shoulder. The positioning shoulder is higher than the base plate, and the positioning shaft is fixedly mounted on the base plate. The positioning shoulder mates with the inner side of the inner cylinder. The positioning shoulder can limit the lower end of the inner cylinder and, together with the inner support block, reliably limit the axial direction of the inner cylinder.

[0020] Preferably, the bracket is provided with a positioning stepped hole coaxial with the motor shaft, and the positioning hole corresponds to the axis of the positioning stepped hole; the pressure cap is provided with a positioning protrusion corresponding to the positioning stepped hole. The positioning protrusion and the positioning stepped hole cooperate to achieve synchronous positioning in both the circumferential and axial directions, ensuring reliable positioning and facilitating the pressure cap to tighten the bracket.

[0021] Preferably, the mounting ring has several mounting through holes, and the inner support block has mounting screw holes coaxially corresponding to the mounting through holes. A connecting bolt, passing through the mounting through holes and engaging with the mounting screw holes, is threaded onto the inner support block. A return spring is fitted onto the connecting bolt, abutting against the inner support block and the mounting ring. The return spring provides an upward elastic force to the inner support block. Under the action of the return spring, the inner block can detach partially from the inner cylinder and fit against the bracket. During the downward locking process of the pressure cap, the elastic force of the return spring is overcome, and the pressure cap and the inner support block are locked, completing the overall positioning and fixing of the bracket, inner cylinder, and outer cylinder, ensuring reliable operation.

[0022] Preferably, the locking element is a clamping bolt threaded to the connecting shaft; the upper end of the positioning shaft is provided with a guide post that is slidably connected to the gland. The bracket and the guide post also slide together, and the tightening of the clamping bolt gradually presses the gland downwards, realizing the gradual force application to the gland and the inner cylinder. The clamping effect is stable, and the center of gravity and axis are not easily offset, ensuring the coaxiality of the inner cylinder, outer cylinder and bracket welding assembly.

[0023] Preferably, four positioning blocks are provided, divided into two groups. These groups are arranged in a circumferential array around the lower mold axis. Each group includes two unit blocks symmetrically arranged on both sides of the lower mold. The lower mold has positioning holes corresponding to the unit blocks. A T-shaped groove extending to the outside of the lower mold is provided between the opposite sides of the two positioning holes in a given group. A locking component corresponding to the T-shaped groove is provided on the lower mold. The distance between the opposite sides of the two unit blocks is equal to the diameter of the outlet on the outer cylinder. The positioning blocks not only position the outer and inner cylinders coaxially but also position the outlet, ensuring reliable fixation of the positions of the components to be welded between the inner and outer cylinders. The T-shaped groove facilitates the installation of the positioning blocks in the positioning holes. When locking the positioning blocks, simply operate the locking component; the locking component clamps the T-shaped groove, locking the positioning block in place. Both unit blocks in the same positioning block group are locked simultaneously, making operation convenient.

[0024] The beneficial effects of this invention are: the sheet metal forming motor cylinder structure can ensure the accuracy of the motor cylinder without subsequent precision machining, thus reducing the production cost of the motor cylinder; the welding operation is convenient and the welding positioning is accurate and reliable. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the sheet metal structure in this invention.

[0026] Figure 2 This is an internal sectional view of the sheet metal structure of the present invention.

[0027] Figure 3 This is an exploded view of the sheet metal structure in this invention.

[0028] Figure 4 This is a schematic diagram of the assembly of the sheet metal structure and welding positioning fixture of the present invention.

[0029] Figure 5 This is a top view of the lower mold in this invention.

[0030] Figure 6 This is a schematic diagram of the pressure cap structure in this invention.

[0031] Figure 7 This is a half-sectional schematic diagram of the inner support block in this invention.

[0032] Figure 8This is a half-sectional schematic diagram of the lower mold in this invention.

[0033] Figure 9 This is a schematic diagram of the positioning block in this invention.

[0034] Figure 10 This is a schematic diagram comparing the structure of the welding positioning fixture of the present invention before and after the pressure cap is locked.

[0035] In the diagram: Inner cylinder 1, First flange 11, Third flange 12, Outer cylinder 2, Outlet 21, Second flange 22, Fourth flange 23, Bracket 3, Positioning hole 31, Positioning step hole 32, Shoulder 33, Water groove 34, Water passage 35, Lower mold 4, Base plate 41, "T" groove 411, Locking component 412, Positioning shoulder 42, Connecting shaft 43, Leveling frustum 44, Mounting protrusion 45, Positioning block 46, Positioning shaft 47, Guide post 48, Pressure cap 5, Positioning protrusion 51, Clearance groove 52, Inner support block 6, Connecting bolt 61, Return spring 62, Locking component 7. Detailed Implementation

[0036] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0037] like Figures 1 to 3 As shown, the sheet metal structure disclosed in this application is a water pump cylinder, including an inner cylinder 1, an outer cylinder 2, and a support 3. The motor assembly is located inside the inner cylinder 1. The inner cylinder 1 and the outer cylinder 2 are coaxially fitted and sealed at both ends, forming an annular water passage 35 between the inner cylinder 1 and the outer cylinder 2. The support 3 is located at the front end of the inner cylinder 1 and the outer cylinder 2, and the support 3 is provided with six water passage grooves 34, which are arranged in a circumferential array around the axis of the inner cylinder 1. The rear end side wall of the outer cylinder 2 is provided with a water outlet 21. The water transported by the water pump impeller can enter the water passage 35 from the water passage grooves 34 and flow out from the water outlet 21, realizing heat dissipation of the motor assembly. The inner cylinder 1 and the outer cylinder 2 are both cylindrical in shape. The end of the inner cylinder 1 facing the support 3 is provided with an inwardly folded first flange 11, which is fitted and connected to the support 3. The end of the outer cylinder 2 facing the support 3 is provided with an outwardly folded second flange 22. The support 3 is approximately disc-shaped. The bracket 3 has a shoulder 33 that mates with the second flange 22. The inner cylinder 1 has a third flange 12 that folds outward at the end away from the bracket 3, and the outer cylinder 2 has a fourth flange 23 that folds inward at the end away from the bracket 3. The third flange 12 and the fourth flange 23 overlap. The first flange 11, the second flange 22, the third flange 12, and the fourth flange 23 are all annular in shape. The bracket 3 has a positioning hole 31 corresponding to the motor shaft. The positioning hole 31 is coaxial with the inner cylinder 1. The bracket 3 also has a positioning stepped hole that is coaxial with the motor shaft. The positioning hole 31 corresponds to the axis of the positioning stepped hole.

[0038] Example 1,

[0039] like Figures 1 to 9 As shown, a welding positioning fixture for assembling and welding sheet metal structures includes a lower mold 4, on which positioning blocks 46 and positioning shafts 47 are provided. The positioning blocks 46 are arranged in a circle, and their inner circumference matches the outer diameter of the outer cylinder 2. The end of the positioning shaft 47 is provided with a pressure cap 5, and the pressure cap 5 and the lower mold 4 are respectively provided with several clearance grooves 52 for welding clearance. The upper end of the positioning shaft 47 is provided with a guide post 48 that is slidably connected to the pressure cap 5. The end of the bracket 3 is provided with six small round holes, and the guide post 48 is slidably engaged with the small round holes. The guide post 48 and the corresponding positioning shaft 47 are provided with two posts arranged around the center of the axis of the lower mold 4. The lower mold 4 includes a base plate 41 and a positioning shoulder 42. The positioning shoulder 42 is cylindrical in shape, and its upper end is provided with a frustum-shaped chamfer. The height of the positioning shoulder 42 is higher than that of the base plate 41. The positioning shaft 47 is fixedly mounted on the base plate 41, and the positioning shoulder 42 engages with the inner side of the inner cylinder 1. A connecting shaft 43 is provided at the axis of the lower mold 4, and a mounting protrusion 45 is fixedly mounted on the connecting shaft 43. The mounting protrusion 45 is cylindrical. An inner support block 6 is provided on the mounting protrusion 45, and six mounting through holes are arranged in a circumferential array around the axis of the mounting protrusion 45. The inner support block 6 is provided with mounting screw holes coaxially corresponding to the mounting through holes. A connecting bolt 61 is threaded onto the inner support block 6, passing through the mounting through holes and engaging with the mounting screw holes. A return spring 62 is sleeved on the connecting bolt 61 to abut against the inner support block 6 and the mounting protrusion 45.

[0040] The connecting shaft 43 is provided with a leveling frustum 44 corresponding to the inner support block 6. The inner support block 6 and the leveling frustum 44 are engaged by the frustum surface. The outer periphery of the inner support block 6 is engaged with the inner side of the inner cylinder 1. The pressure cover 5 is provided with a locking member 7 corresponding to the connecting shaft 43. The locking member 7 is a clamping bolt that is threadedly connected to the connecting shaft 43. The pressure cover 5 is provided with a positioning surface that engages with the bracket 3. The positioning surface of the pressure cover 5 includes a positioning protrusion 51 corresponding to the positioning stepped hole.

[0041] Four positioning blocks 46 are provided, and the inner sides of the four positioning blocks 46 are located on the same cylindrical surface. The height of the positioning blocks 46 is higher than that of the base plate 41, and the height of the positioning blocks 46 is the same as that of the positioning shoulder 42. The four positioning blocks 46 are divided into two groups of positioning blocks 46, which are arranged in a circumferential array around the axis of the lower mold 4. Each group of positioning blocks 46 includes two unit blocks symmetrically arranged on both sides of the lower mold 4. The lower mold 4 is provided with positioning holes 31 corresponding to the unit blocks. A "T"-shaped groove 411 extending to the outside of the lower mold 4 is provided between the opposite sides of the two positioning holes 31 of the corresponding group of positioning blocks 46. The lower mold 4 is provided with a locking component 412 corresponding to the "T"-shaped groove 411. The distance between the opposite sides of the two unit blocks is equal to the diameter of the water outlet 21 on the outer cylinder 2. The locking component 412 is a bolt. The base plate 41 is provided with a notch, and the two groove walls of the notch are parallel and perpendicular to the groove walls of the "T"-shaped groove 411, respectively. The notch facilitates the installation of the locking component 412.

[0042] Example 2,

[0043] A method for assembling a sheet metal structure includes the following steps:

[0044] A. Sheet metal is used to fabricate an inner cylinder 1 and an outer cylinder 2. The inner cylinder 1, outer cylinder 2, and bracket 3 are positioned, with the inner cylinder 1 and bracket 3 using the same datum. The welding positioning fixture of this application is used. After the return spring 62 is fitted on the connecting bolt 61, the inner support block 6 is connected. The leveling frustum 44 and the frustum surface are pre-fitted. The inner cylinder 1, outer cylinder 2, and bracket 3 are sequentially installed on the lower mold 4 and the positioning shaft 47. The inner support block 6 and the positioning shaft shoulder 42 correspond to the inner circumference of the upper and lower ends of the inner cylinder 1, respectively. The inner sides of the four positioning blocks 46 position the lower outer side of the outer cylinder 2. After the bracket 3 is pre-positioned by the guide post 48 on the positioning shaft 47, the pressure cover 5 and the connecting shaft 43 are installed. The positioning protrusion 51 on the pressure cover 5 and the positioning stepped hole of the bracket 3 are fitted to lock the locking piece 7. The pressure cover 5 is pressed against the inner support block 6, and the inner cylinder 1, outer cylinder 2, and bracket 3 are simultaneously locked based on the axis of the lower mold 4. Figure 10 The left half of the middle view shows the position of the pressure cap 5 and the inner support block 6 when the locking part 7 is locked, and the right half of the middle view shows the position of the pressure cap 5 and the inner support block 6 when the locking part 7 is released; the positioning of the inner cylinder 1 and the bracket 3 is achieved through the positioning hole 31 and the positioning of the inner cylinder 1;

[0045] B. Welding bracket 3 and inner cylinder 1;

[0046] C. The flange of the outer cylinder 2 is matched with the bracket 3, the shoulder 33 is matched with the second flange 22 for positioning, and the outer cylinder 2 and the bracket 3 are welded.

[0047] D. After the third flange 12 and the fourth flange 23 are attached, they are welded together to weld the outer cylinder 2 and the inner cylinder 1.

[0048] Laser welding is used for welding in steps B, C, and D. The pressure cap 5 has twelve clearance grooves 52 arranged in two concentric rings. These grooves are divided into two groups of six. In this embodiment, the clearance grooves 52 have a circular hole structure. The two groups of clearance grooves 52 on the pressure cap 5 correspond to the welding points of the inner cylinder 1 and the support 3, and the outer cylinder 2 and the support 3, respectively. After positioning the inner cylinder 1, outer cylinder 2, and support 3 through laser spot welding at twelve locations, laser welding is continued to complete the circular welding at the positions of the first flange 11 and the second flange 22. The bottom plate 41 of the lower mold 4 has six circumferential clearance grooves 52. Similarly, they are first positioned and spot welded, and then the tooling is removed for complete circular welding.

[0049] This application provides an assembly method for welding a double-layer motor cylinder sheet metal, which can reduce the production cost of the motor cylinder. The positioning of the inner cylinder 1, outer cylinder 2 and bracket 3 is based on the same axis. During welding, the tooling plays a reliable clamping and positioning role, ensuring the accuracy of the sheet metal welding positioning, and ensuring the roundness and concentricity of the structure.

Claims

1. A method for assembling a sheet metal structure, characterized in that, Includes the following steps: A. Sheet metal is used to fabricate the inner and outer cylinders, and the inner and outer cylinders and the bracket are positioned. The inner cylinder and the bracket use the same reference. The bracket is provided with positioning holes corresponding to the motor shaft, and the positioning holes are coaxial with the inner cylinder. B. Welding brackets and inner cylinder; C. The flange of the outer cylinder is positioned to cooperate with the bracket, and the outer cylinder and the bracket are welded together; the inner cylinder has an inwardly folded first flange at the end facing the bracket, and the first flange is fitted and connected to the bracket; the outer cylinder has an outwardly folded second flange at the end facing the bracket, and the bracket has a shoulder part that cooperates with the second flange. D. Weld the outer cylinder and the inner cylinder; the inner cylinder has a third flange that folds outward at the end away from the support, and the outer cylinder has a fourth flange that folds inward at the end away from the support, with the third flange and the fourth flange overlapping.

2. The assembly method for a sheet metal structure according to claim 1, characterized in that, In step A, the positioning of the inner cylinder and the bracket is achieved through the positioning holes and the positioning of the inner cylinder.

3. The assembly method for a sheet metal structure according to claim 1, characterized in that, In step C, the shoulder of the shaft is positioned in conjunction with the second flange.

4. The assembly method for a sheet metal structure according to claim 1, characterized in that, In step D, the third and fourth flanges are welded together.

5. A welding positioning fixture applied to the assembly method of the sheet metal structure according to any one of claims 1 to 4, characterized in that, The device includes a lower mold, on which a positioning block and a positioning shaft are provided. The inner circumference of the positioning block matches the outer diameter of the outer cylinder. A pressure cap is provided at the end of the positioning shaft. A connecting shaft is provided at the axis of the lower mold. A mounting convex ring is fixed on the connecting shaft. An inner support block is provided on the mounting convex ring. A leveling platform corresponding to the inner support block is provided on the connecting shaft. The inner support block and the leveling platform cooperate through the platform surface. The outer circumference of the inner support block cooperates with the inner side of the inner cylinder. A locking element corresponding to the connecting shaft is provided on the pressure cap. A positioning surface that cooperates with the bracket is provided on the pressure cap. Several clearance grooves for welding clearance are provided on the pressure cap and the lower mold, respectively.

6. The welding positioning fixture for an assembly method of sheet metal structures according to claim 5, characterized in that, The lower mold includes a base plate and a positioning shoulder. The height of the positioning shoulder is higher than that of the base plate. The positioning shaft is fixedly mounted on the base plate, and the positioning shoulder cooperates with the inner side of the inner cylinder.

7. The welding positioning fixture for an assembly method of sheet metal structures according to claim 5, characterized in that, The bracket is provided with a positioning stepped hole coaxial with the motor shaft, and the positioning hole corresponds to the axis of the positioning stepped hole; the cover is provided with a positioning protrusion corresponding to the positioning stepped hole.

8. The welding positioning fixture for an assembly method of sheet metal structures according to claim 5, characterized in that, The mounting protruding ring is provided with several mounting through holes, and the inner support block is provided with mounting screw holes that are coaxially corresponding to the mounting through holes. The inner support block is threaded with a connecting bolt that passes through the mounting through holes and mates with the mounting screw holes. A return spring that abuts against the inner support block and the mounting protruding ring is sleeved on the connecting bolt.

9. The welding positioning fixture for an assembly method of sheet metal structures according to claim 5, characterized in that, The locking component is a clamping bolt that is threadedly connected to the connecting shaft; the upper end of the positioning shaft is provided with a guide post that is slidably connected to the pressure cover.

10. The welding positioning fixture for an assembly method of sheet metal structures according to claim 5, characterized in that, The positioning block consists of four blocks, which are divided into two groups. The two groups are arranged in a circumferential array around the lower mold axis. Each group includes two unit blocks symmetrically arranged on both sides of the lower mold. The lower mold has positioning holes corresponding to the unit blocks. A "T"-shaped groove extending to the outside of the lower mold is provided between the opposite sides of the two positioning holes of a group. The lower mold has a locking component corresponding to the "T"-shaped groove.

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