An automated welding device for hydraulic vehicle oil pumps

Abstract

This invention discloses an automated welding device for automotive hydraulic pumps, comprising a welding production line and a conveyor plate. The welding production line includes an outer cover, a welding robotic arm, and a conveyor. The conveyor plate has multiple retaining components that are configured to limit the movement of the hydraulic pump assembly. This automated welding device for automotive hydraulic pumps uses retaining components that can be arbitrarily fixed in position to position and fix different models of automotive hydraulic pump assemblies, allowing them to move stably on the conveyor line. Welding is then performed by the welding robotic arm on the conveyor line. Furthermore, fixing the components eliminates the need for complex piping structures, reducing investment and simplifying the entire welding production line, avoiding the negative impact of complex piping on welding. The detachable retaining components also facilitate rapid positioning of the automotive hydraulic pump assembly to be welded.

Description

Technical Field

[0001] This invention relates to welding technology, and more particularly to an automated welding device for hydraulic pumps. Background Technology

[0002] The fuel pump is one of the basic components of the fuel injection system in electronic fuel injection vehicles. It is located inside the vehicle's fuel tank and its function is to draw fuel from the fuel tank, pressurize it, and deliver it to the fuel supply line, working in conjunction with the fuel pressure regulator to establish a certain fuel pressure.

[0003] During the manufacturing process of the oil pump, the main body needs to be welded together from multiple individual components to form a complete main structure. During welding, each individual component needs to be positioned to ensure proper contact and welding accuracy before assembly. Currently, the fixed jigs mainly use electric actuators or hydraulic cylinders for positioning, but this results in complex piping in automated welding production lines, making the entire welding line structure cumbersome and hindering the welding operation of the robotic arm. Furthermore, different models of oil pumps have different structures, requiring the existing fixed jigs to be reassembled and the piping structure to be redesigned, which consumes considerable time and cost, hindering actual oil pump welding operations. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention proposes an automated welding device for hydraulic vehicle oil pumps.

[0005] An automated welding device for hydraulic vehicle oil pumps, comprising:

[0006] A welding production line, which is equipped with an outer cover, a welding robotic arm, and a conveyor line;

[0007] A conveyor plate is installed on the conveyor line to fix the hydraulic pump assembly to be welded. The conveyor plate is provided with multiple retaining components that are matched and limited according to the structure of the hydraulic pump assembly. The retaining components include:

[0008] A fixed base is provided on a conveyor plate, and an insertion cylinder is provided on the fixed base, with an insertion hole formed inside the insertion cylinder;

[0009] A retainer is disposed within an insertion hole, a pusher is provided in the middle of the retainer, and a first spring is provided between the pusher and the retainer.

[0010] A rotating member is disposed outside the retainer. The rotating member has a retaining block that cooperates with the pusher. When the rotating member rotates, it drives the retaining block to rotate as well, and pushes the pusher toward the fixed seat through the retaining block, while keeping the first spring compressed. The pusher pushes the retainer, causing it to deform under force.

[0011] A mounting component connected to a rotating component, the mounting component having a pressure-applying component, the mounting component being connected to the rotating component via a connector, thereby allowing the mounting component to rotate at any angle on the rotating component.

[0012] In this invention, the retaining member is composed of a first column, a second column, and a connecting body. The connecting body connects the first column and the second column. A third column is provided at the lower end of the connecting body. A first stepped hole, a second stepped hole, and a through hole are formed between the connecting body and the third column.

[0013] In this invention, the lower end of the third column is provided with symmetrically arranged elastic arms. In its natural state, the lower ends of the elastic arms are kept close to each other. A pushing area is formed between the elastic arms. The elastic arms are provided with positioning protrusions. The middle of the fixing seat is provided with a fixing hole that cooperates with the positioning protrusions. The inner diameter of the fixing hole is larger than the inner diameter of the insertion hole.

[0014] In this invention, the pusher consists of a pusher end and a rod body. The first spring is sleeved on the rod body and located at the lower end of the pusher end. The first spring is disposed in the second stepped hole. The lower end of the rod body extends through the through hole into the pusher area.

[0015] In this invention, the retaining block and the rotating component are connected by a positioning pin. The lower end of the retaining block is provided with a guiding arc surface and a positioning groove, and the pushing component cooperates with the positioning groove for limiting position.

[0016] In this invention, a rotating hole is formed in the middle of the rotating member, and an avoidance groove that cooperates with the pushing member is provided on the inner wall of the rotating hole. The distance between the avoidance groove and the center line of the rotating hole is greater than the distance between the positioning groove and the center line of the rotating hole.

[0017] In this invention, the rotating component is provided with a connecting rod, and the connecting rod is also provided with a positioning rod, with an annular groove formed in the middle of the positioning rod.

[0018] In this invention, the mounting component has a connecting hole in the middle that mates with the connecting rod, and an annular protrusion is provided inside the connecting hole. A limiting hole is formed in the middle of the annular protrusion, and the inner diameter of the limiting hole is smaller than the inner diameter of the connecting hole.

[0019] In this invention, the connector is inserted into the limiting hole through the connecting hole. The connector consists of an annular edge and a limiting sleeve. The limiting sleeve has a communicating hole in the middle that mates with the connecting rod. The limiting sleeve has symmetrically arranged square holes. A deformation arm is provided in the square hole. One end of the deformation arm has a positioning edge and the other end has a limiting edge. The positioning edge mates with the annular protrusion and the limiting edge mates with the annular groove.

[0020] In this invention, the pressure-applying component consists of a threaded rod and a pressure-applying end. The mounting component has a through hole that mates with the threaded rod. The pressure-applying end is located at the lower end of the threaded rod. A nut is provided on the threaded rod, and the nut is located at the upper end of the mounting component. A second spring is provided between the mounting component and the pressure-applying end, and the second spring is sleeved on the threaded rod.

[0021] The automated welding device for automotive hydraulic pumps according to this invention has the following advantages: This device uses a retaining component that can be arbitrarily fixed in position to position and fix different models of automotive hydraulic pump assemblies, allowing them to move stably on the conveyor line. Welding is then performed by a welding robotic arm on the conveyor line. Furthermore, during fixing, there is no need to lay cumbersome pipeline structures, reducing capital investment and simplifying the entire welding production line, avoiding the impact of complex pipelines on welding. Simultaneously, the detachable retaining component facilitates rapid positioning of the automotive hydraulic pump assembly to be welded. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the automated welding device for hydraulic vehicle oil pumps of the present invention;

[0023] Figure 2 This is a schematic diagram of the conveyor plate and holding assembly structure in this invention;

[0024] Figure 3 for Figure 2 A schematic diagram of the retaining component structure;

[0025] Figure 4 for Figure 3 Top view;

[0026] Figure 5 for Figure 4 Cross-sectional view at point AA;

[0027] Figure 6 for Figure 3 Exploded view;

[0028] Figure 7 for Figure 6 Cross-sectional view of the installation components in the diagram;

[0029] Figure 8 for Figure 6 A schematic diagram of the connector structure in the diagram;

[0030] Figure 9 for Figure 8 A schematic diagram of the structure in another direction;

[0031] Figure 10 for Figure 8Perspective view;

[0032] Figure 11 This is a schematic diagram of the installation state of the mounting components and connectors in this invention;

[0033] Figure 12 for Figure 6 A schematic diagram of the rotating component structure in the diagram;

[0034] Figure 13 for Figure 12 Main perspective view;

[0035] Figure 14 This is a schematic diagram of the installation state of the connecting rod and connector structure in this invention;

[0036] Figure 15 for Figure 6 A schematic diagram of the retainer structure in the middle;

[0037] Figure 16 for Figure 15 Main perspective view;

[0038] Figure 17 for Figure 6 A schematic diagram of the pusher and the first spring structure in the middle;

[0039] Figure 18 for Figure 6 A schematic diagram of the retaining block structure in the diagram;

[0040] Figure 19 This is a schematic diagram showing the installation state of the retaining block and rotating component structure in this invention;

[0041] Figure 20 This is a perspective view of the installation state of the fixed base, pusher, retainer, first spring, rotating member and retaining block structure in this invention.

[0042] In the diagram: 1. Welding production line; 2. Conveyor plate; 3. Outer cover; 4. Welding robotic arm; 5. Conveyor line; 6. Lifting mechanism; 7. Holding assembly; 8. Fixed seat; 9. Holding component; 10. Rotating component; 11. Mounting component; 12. Screw hole; 13. Pressure applying component; 14. Insertion cylinder; 15. Insertion hole; 16. Elastic arm; 17. Pushing component; 18. Positioning protrusion; 19. Fixing hole; 20. First spring; 21. Holding block; 22. First column; 23. Second column; 24. Connecting body; 25. Third column; 26. First stepped hole; 27. Second stepped hole; 28. Through hole; 29. ​​Holding rod; 30. Holding hole; 31. Pushing area; 32. Arc-shaped surface; 33. Guide slope; 34. Rod. 35. Conical surface, 36. Pushing end, 37. Positioning pin, 38. Receiving area, 39. Rotating hole, 40. Guide arc surface, 41. Positioning groove, 42. Avoidance groove, 43. Loading port, 44. Avoidance groove, 45. Blocking part, 46. Notch, 47. Connecting rod, 48. Positioning rod, 49. Annular groove, 50. Connecting hole, 51. Annular protrusion, 52. Limiting hole, 53. Limiting area, 54. Positioning area, 55. Connecting piece, 56. Annular edge, 57. Limiting sleeve, 58. Connecting hole, 59. Square hole, 67. Deformation arm, 61. Limiting edge, 62. Threaded rod, 63. Pressing end, 64. Through hole, 65. Nut, 66. Second spring, 67. Deformation arm, 68. Deformation port. Detailed Implementation

[0043] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0044] like Figures 1 to 20 As shown, this automated welding device for hydraulic oil pumps of the present invention includes a welding production line 1 and a conveyor plate 2. The conveyor plate 2 cooperates with the welding production line 1, allowing the conveyor plate 2 to move on the welding production line 1, so that the hydraulic oil pump assembly on the conveyor plate 2 can move together. Other structures of the welding production line 1 can employ existing technology, and therefore will not be described in detail here.

[0045] The welding production line 1 is equipped with an outer cover 3, a welding robotic arm 4, and a conveyor line 5. The welding robotic arm 4 operates inside the outer cover 3, which has an exhaust pipe for absorbing the fumes generated during welding. Lifting mechanisms 6 are installed at both ends of the conveyor line 5. These mechanisms allow the upper conveyor plate 2 to be moved to the lower end, and vice versa, enabling the reciprocating movement of the conveyor plate 2. The welding robotic arm 4 can cooperate with a plasma-argon arc welding machine, allowing it to control the welding handle of the machine.

[0046] The conveyor plate 2 is mounted on the conveyor line 5. The conveyor plate 2 is used to fix the hydraulic pump assembly to be welded. The conveyor plate 2 has multiple retaining components 7 that are designed to limit the movement of the hydraulic pump assembly. Each retaining component 7 includes a fixed base 8, a retaining member 9, a rotating member 10, and a mounting member 11. The fixed base 8 is mounted on the conveyor plate 2 and has multiple screw holes 12 for bolt engagement. The retaining member 9 is fitted with the fixed base 8 to limit its movement, preventing it from moving or rotating. The rotating member 10 can rotate on the retaining member 9, thus limiting the movement between the retaining member 9 and the fixed base 8. The mounting member 11 is connected to the rotating member 10. When the rotating member 10 rotates, the mounting member 11 can rotate with the rotating member 10 or remain stationary. Furthermore, a pressure-applying component 13 is provided on the mounting component 11. The pressure-applying component 13 is used to limit the automotive hydraulic oil pump assembly that needs to be positioned, so that it cannot move and facilitates the welding robotic arm 4 to perform welding operations.

[0047] The fixed base 8 is set on the conveyor plate 2. The fixed base 8 is provided with an insertion cylinder 14. An insertion hole 15 is formed in the insertion cylinder 14. The insertion hole 15 is used for the insertion of the elastic arm 16, which is pushed by the pusher 17 and kept open in opposite directions. This makes the positioning protrusion 18 located at the lower end of the insertion hole 15 and kept inside the fixed hole 19. The position of the positioning protrusion 18 is limited by the contact surface between the insertion hole 15 and the fixed hole 19.

[0048] The retainer 9 is disposed in the insertion hole 15. The retainer 9 has a pusher 17 in the middle. A first spring 20 is provided between the pusher 17 and the retainer 9. The first spring 20 is used to reset the position of the pusher 17 so that it can be compressed by the pusher 17 when pushed by the retainer block 21, thereby generating elastic potential energy. After the retainer block 21 is reset with the rotating member 10, the first spring 20 can push the pusher 17 upward to reset it, so that the lower end of the pusher 17 no longer pushes the elastic arm 16, thereby resetting the elastic arm 16 and no longer keeping it in contact with the contact surface, so that the lower ends of the two elastic arms 16 re-contact.

[0049] The retainer 9 is composed of a first column 22, a second column 23 and a connector 24. The connector 24 connects the first column 22 and the second column 23. The lower end of the connector 24 is provided with a third column 25. A first stepped hole 26, a second stepped hole 27 and a through hole 28 are formed between the connector 24 and the third column 25.

[0050] Multiple retaining rods 29 are provided at the lower end of the connector 24, and retaining holes 30 that cooperate with the retaining rods 29 are provided on the insertion cylinder 14. Through the cooperation of the retaining rods 29 and the retaining holes 30, the third column 25 can no longer be inserted into the hole 15 and rotate.

[0051] Of course, to facilitate actual needs, multiple retaining holes 30 can be provided, and the angle between retaining holes 30 and retaining holes 30 can be reduced, so that the retaining member 9 can be adjusted according to actual needs during insertion and installation, and adapted to the structure of the automotive hydraulic oil pump assembly.

[0052] The lower end of the third column 25 is provided with symmetrically arranged elastic arms 16. In the natural state, the lower ends of the elastic arms 16 are kept close to each other. A pushing area 31 is formed between the elastic arms 16 and the elastic arms 16. The elastic arms 16 are provided with positioning protrusions 18. The middle of the fixed seat 8 is provided with a fixing hole 19 that cooperates with the positioning protrusions 18. The inner diameter of the fixing hole 19 is larger than the inner diameter of the insertion hole 15.

[0053] Meanwhile, an arc-shaped surface 32 and a guide slope 33 are provided at the lower end of the elastic arm 16. The arc-shaped surface 32 and the guide slope 33 cooperate with the rod 34 to make the rod 34 located in the middle of the arc-shaped surface 32. The guide slope 33 can cooperate with the tapered surface 35 at the lower end of the rod 34. By sliding the tapered surface 35 on the guide slope 33, the lower end of the elastic arm 16 is pushed, keeping the lower ends of the two elastic arms 16 moving and opening in opposite directions.

[0054] The pusher 17 consists of a pusher end 36 and a rod body 34. A first spring 20 is sleeved on the rod body 34 and located at the lower end of the pusher end 36. The first spring 20 is disposed in the second stepped hole 27. The lower end of the rod body 34 extends through the through hole 28 into the pusher area 31.

[0055] The rotating member 10 is disposed outside the retaining member 9. The rotating member 10 has a retaining block 21 that cooperates with the pushing member 17. When the rotating member 10 rotates, it drives the retaining block 21 to rotate as well, and pushes the pushing member 17 toward the fixed seat 8 through the retaining block 21, while keeping the first spring 20 compressed. The pushing member 17 pushes the retaining member 9, causing it to deform under force.

[0056] The retaining block 21 is connected to the rotating member 10 by a positioning pin 37, allowing the retaining block 21 to rotate with the rotating member 10. Since a receiving area 38 is formed between the first column 22 and the second column 23 of the retaining member 9, the retaining block 21 can be placed within the receiving area 38, thereby restricting the position of the retaining member 9 and preventing it from moving out of the rotating hole 39. The lower end of the retaining block 21 is provided with a guiding arc surface 40 and a positioning groove 41, and the pushing member 17 cooperates with the positioning groove 41 for positioning limitation.

[0057] Meanwhile, a rotating hole 39 is formed in the middle of the rotating member 10. The inner wall of the rotating hole 39 is provided with a relief groove 42 that cooperates with the push member 17. The distance between the relief groove 42 and the center line of the rotating hole 39 is greater than the distance between the positioning groove 41 and the center line of the rotating hole 39.

[0058] The rotating member 10 has a loading port 43 for the retaining block 21 and a clearance groove 44 to facilitate rotation and avoid the insertion cylinder 14. A blocking part 45 is provided between the clearance groove 44 and the loading port 43 to block the rotation angle of the rotating member 10. The rotating member 10 also has a notch 46 that communicates with the rotating hole 39 and the clearance groove 44. The notch 46 is used to allow the retaining member 9 to be installed into the rotating hole 39 and to allow the retaining third column 25 to move into the clearance groove 44 within the notch 46.

[0059] A connecting rod 47 is provided on the rotating component 10, and a positioning rod 48 is also provided on the connecting rod 47. An annular groove 49 is formed in the middle of the positioning rod 48. The outer diameter of the annular groove 49 is smaller than the outer diameter of the connecting rod 47. A connecting hole 50 that mates with the connecting rod 47 is provided in the middle of the mounting component 11. An annular protrusion 51 is provided inside the connecting hole 50, and a limiting hole 52 is formed in the middle of the annular protrusion 51. The inner diameter of the limiting hole 52 is smaller than the inner diameter of the connecting hole 50.

[0060] Furthermore, since the connecting hole 50 is provided with an annular protrusion 51, the annular protrusion 51 divides the connecting hole 50, keeping the other end of the connecting hole 50 forming a limiting area 53. The deformation is within the limiting area 53. Within the limiting area 53, there is also a positioning area 54 that cooperates with the positioning rod 48, which enhances the connection stability of the connecting rod 47.

[0061] The mounting component 11 is connected to the rotating component 10. The mounting component 11 has a pressure member 13. The mounting component 11 is connected to the rotating component 10 through a connector 55, so that the mounting component 11 can rotate at any angle on the rotating component 10.

[0062] The connector 55 is inserted into the limiting hole 52 through the connecting hole 50. The connector 55 consists of an annular edge 56 and a limiting sleeve 57. The limiting sleeve 57 has a connecting hole 58 in the middle that mates with the connecting rod 47. The limiting sleeve 57 has symmetrically arranged square holes 59, and a deformation arm 67 is provided in the square hole 59. The deformation arm 67 mates with the annular groove 49 for limiting. One end of the deformation arm 67 has a positioning edge 60, and the other end has a limiting edge 61. The positioning edge 60 mates with the annular protrusion 51, and the limiting edge 61 mates with the annular groove 49. Since the positioning edge 60 is set outward, while the limiting edge 61 is set inward, and the annular protrusion 51 is located outside the connector 55, while the connecting rod 47 is located inside the connector 55. The connector 55 also has a deformation port 68 to facilitate the deformation of the connector 55 under force.

[0063] The pressure-applying component 13 consists of a threaded rod 62 and a pressure-applying end 63. The mounting component 11 is provided with a through hole 64 that mates with the threaded rod 62. The pressure-applying end 63 is located at the lower end of the threaded rod 62. A nut 65 is provided on the threaded rod 62. The nut 65 is located at the upper end of the mounting component 11. A second spring 66 is provided between the mounting component 11 and the pressure-applying end 63. The second spring 66 is sleeved on the threaded rod 62.

[0064] If it is necessary to adjust the distance between the pressure end 63 and the automotive hydraulic pump assembly, the nut 65 can be rotated to adjust the distance between the pressure end 63 and the mounting part 11. A greater compression of the second spring 66 results in a smaller distance between the pressure end 63 and the mounting part 11, and vice versa. The distance can be adjusted according to different positions of the automotive hydraulic pump assembly to accommodate different heights. Additionally, depending on actual needs, mounting brackets 8 of different heights can be provided to accommodate automotive hydraulic pump assemblies of different shapes.

[0065] When it is necessary to limit the operation of the automotive hydraulic pump assembly, first remove the conveyor plate 2, then make a jig, place different numbers of fixing seats 8 according to the structure of the automotive hydraulic pump assembly to be welded, and then fix the fixing seats 8 onto the conveyor plate 2. Next, the individual components of the automotive hydraulic pump assembly to be welded are placed. By mates the retainer 9, rotating member 10, mounting member 11, and pressure-applying member 13 mounted together with the fixed base 8, the retainer 9 is inserted into the insertion hole 15. Then, the rotating member 10 is rotated, causing the pusher 17, originally placed in the clearance groove 42, to move into the positioning groove 41 guided by the guide arc surface 40, thereby limiting the position of the pusher 17. The first spring 20 is compressed, causing the pusher 17 to move downward toward the fixed hole 19. During the downward movement, the rod 34 on the pusher 17 moves along the guide slope 33 at the lower end of the elastic arm 16, pushing the elastic arm 16 away from it and causing it to move in the opposite direction. The maximum distance between the positioning protrusions 18 is greater than the inner diameter of the insertion hole 15, thereby restricting the retainer 9 within the insertion hole 15. This achieves the position limitation of the rotating member 10, mounting member 11, and pressure-applying member 13.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A hydraulic truck oil pump automated welding apparatus, characterized by, The utility model relates to a welding assembly line, which comprises a cover, a welding robot and a conveying line. The utility model discloses a conveying plate arranged on the conveying line and used for fixing a hydraulic vehicle oil pump assembly to be welded, wherein the conveying plate is provided with a plurality of holding assemblies for limiting the hydraulic vehicle oil pump assembly according to the structure of the hydraulic vehicle oil pump assembly. The holding assembly comprises a fixing seat arranged on the conveying plate, an insertion cylinder arranged on the fixing seat and forming an insertion hole, a holding piece arranged in the insertion hole, a pushing piece arranged in the middle of the holding piece, a first spring arranged between the pushing piece and the holding piece, a rotating piece arranged outside the holding piece and provided with a holding block matched with the pushing piece, and a mounting piece connected with the rotating piece and provided with a pressing piece. The rotating piece rotates to drive the holding block to rotate and push the pushing piece towards the fixing seat, and the first spring is compressed under stress. The pushing piece pushes the holding piece to deform under stress. The mounting piece is connected with the rotating piece through a connecting piece and can rotate at any angle on the rotating piece. The holding piece is composed of a first column, a second column and a connecting body.

2. The hydraulic truck pump automated welding apparatus of claim 1, wherein, The lower end of the third column is provided with symmetrical elastic arms that naturally keep close to each other.

3. The hydraulic truck pump automated welding apparatus of claim 2, wherein, The pushing piece is composed of a pushing end and a rod body.

4. The hydraulic truck pump automated welding apparatus of claim 3, wherein, The holding block is connected with the rotating piece through a positioning pin.

5. The hydraulic truck pump automated welding apparatus of claim 1, wherein, The rotating piece is provided with a rotating hole in the middle, and the inner wall of the rotating hole is provided with an avoidance groove matched with the pushing piece.

6. The hydraulic truck pump automated welding apparatus of claim 5, wherein, The distance between the avoidance groove and the center line of the rotating hole is greater than the distance between the positioning groove and the center line of the rotating hole.

7. The hydraulic truck pump automated welding apparatus of claim 1, wherein, The rotating piece is provided with a connecting rod, and the connecting rod is further provided with a positioning rod.

8. The hydraulic truck pump automated welding apparatus of claim 7, wherein, The middle of the mounting piece is provided with a connecting hole matched with the connecting rod. The connecting hole is provided with an annular protrusion, and the middle of the annular protrusion forms a limiting hole.

9. The hydraulic truck pump automated welding apparatus of claim 8, wherein, The connecting piece is inserted into the limiting hole through the connecting hole, the connecting piece is composed of an annular edge and a limiting sleeve, a communication hole matched with the connecting rod is arranged in the middle of the limiting sleeve, square holes symmetrically arranged are arranged on the limiting sleeve, a deformation arm is arranged in the square hole, a positioning edge is arranged at one end of the deformation arm, and a limiting edge is arranged at the other end of the deformation arm, the positioning edge is matched and contacted with the annular protrusion, and the limiting edge is matched and contacted with the annular groove.

10. The hydraulic truck pump automated welding apparatus of claim 1, wherein, The pressure applying piece is composed of a threaded rod and a pressure applying end, a through hole matched with the threaded rod is arranged on the mounting piece, the pressure applying end is arranged at the lower end of the threaded rod, a nut is arranged on the threaded rod, the nut is located at the upper end of the mounting piece, a second spring is arranged between the mounting piece and the pressure applying end, and the second spring is sleeved on the threaded rod.

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