Large marine engine piston pin installation tool

Abstract

The utility model discloses a large -scale marine engine piston pin installation frock, including boom mechanism, piston pin support subassembly, piston pin axial swing mechanism and piston pin center hole expansion mechanism, and the vertical fine adjustment mechanism middle part is vertically welded to the one end of suspension arm, and the lifting eye screw is fixed on the suspension arm. The lower extreme of vertical fine adjustment mechanism is connected with the upper extreme of vertical rod, and the lower extreme of vertical rod is fixedly connected with one end of piston pin axial swing mechanism. The bottom center of V-shaped support seat is fixed on the middle part of piston pin axial swing mechanism. The piston pin is supported on V-shaped support seat, and piston pin center hole expansion mechanism is inserted into piston pin center hole and is tightly connected, and the lower extreme of piston pin center hole expansion mechanism is fixedly connected with the middle part of piston pin axial swing mechanism. The utility model is simple to operate, convenient to use, and except using the crane, only one person operation can complete the installation of piston pin, improves the installation efficiency of piston pin obviously, and effectively guarantees the assembly safety of piston pin.

Description

Technical Field

[0001] This utility model relates to a component installation fixture for marine engines, and more particularly to an installation fixture for lifting and installing piston pins into piston pin holes in large marine engines with cylinder diameters exceeding 150mm, belonging to the technical field of marine engine installation fixtures. Background Technology

[0002] The piston pin is a key component in reciprocating engines, connecting the piston to the small end of the connecting rod. It converts the reciprocating linear motion of the piston assembly within the cylinder into the translational motion of the connecting rod, which in turn drives the crankshaft to rotate, thus outputting power. Furthermore, while ensuring sufficient strength, machining a piston pin with a center bore can effectively reduce the overall mass of the piston pin and piston assembly, thereby reducing the inertial forces of the reciprocating motion and improving the smoothness of engine operation.

[0003] When the cylinder diameter of a marine engine reaches 320mm, its piston pin diameter is 145mm, length is 260mm, center hole diameter is 40mm, and weight reaches 31kg. It is impossible to install the piston pin into the piston pin hole by hand; lifting tools are required. Currently, the piston pin is secured with slings and lifted by a crane, with an assembly fitter manually guiding the piston pin to complete the assembly. Because the piston pin surface has a layer of anti-rust oil, there is a risk of slippage during lifting and assembly, posing a significant safety hazard. Furthermore, using a crane to assemble the piston pin into the piston pin hole requires skilled and coordinated cooperation between the assembly fitter and the crane operator, demanding a high level of technical expertise from both. Utility Model Content

[0004] The purpose of this invention is to provide a large marine engine piston pin installation fixture that is easy to adjust and safe and reliable to use.

[0005] This utility model is achieved through the following technical solution:

[0006] A large marine engine piston pin installation fixture includes a lifting rod mechanism, a piston pin support assembly, a piston pin axial swing mechanism, and a piston pin center hole tightening mechanism. The lifting rod mechanism includes a vertical rod, a vertical fine-tuning mechanism, and a lifting arm assembly. The lifting arm assembly includes a lifting arm and an eye bolt. One end of the lifting arm is vertically welded to the middle of the vertical fine-tuning mechanism. A through-groove groove is provided in the longitudinal middle of the lifting arm. The eye bolt passes vertically downward through the through-groove and is clamped and fixed to the lifting arm by a nut. The lower end of the vertical fine-tuning mechanism is connected to the upper end of the vertical rod, and the lower end of the vertical rod is fixed to one end of the horizontally positioned piston pin axial swing mechanism. Fixed connection; the piston pin support assembly includes a V-shaped support seat with an included angle of 90° and a pair of nylon pads symmetrically fixed inside the V-shaped support seat. The V-shaped support seat intersects perpendicularly with the piston pin axial swing mechanism. The bottom center of the V-shaped support seat is provided with an inverted U-shaped groove, which is welded and fixed to the middle of the piston pin axial swing mechanism. The piston pin is supported on the nylon pads inside the V-shaped support seat. The upper end of the piston pin center hole tightening mechanism extends into one end of the piston pin center hole and is tightened and fixedly connected to the piston pin center hole. The lower end of the piston pin center hole tightening mechanism is vertically fixedly connected to the middle of the piston pin axial swing mechanism.

[0007] The objective of this utility model can also be achieved in one step through the following technical measures.

[0008] Furthermore, the piston pin axial swing mechanism includes a fixed shaft, a dovetail block, and a limiting rod. The fixed shaft has an axial dovetail groove on its upper side, and the dovetail block is embedded in the axial dovetail groove. The arc-shaped surface of one end of the bushing abuts against the lower end of one side of the vertical shaft. The fixed shaft is inserted into the bushing, and one end of the fixed shaft is vertically and fixedly connected to the lower end of the vertical shaft. The other end of the fixed shaft extends out of the other end of the bushing and is limited by a shaft retaining ring. The upper side of the bushing near the vertical rod has a groove that is a combination of a right-angled trapezoid in side view and a triangle and rectangle in top view. The lower end of the limiting rod is fixed in the dovetail block, and the upper end of the limiting rod extends out of the groove. The bottom of both sides of the groove is higher than the horizontal center line of the bushing. The swing angle α of the limiting rod is ≤110°.

[0009] Furthermore, the piston pin center hole tensioning mechanism is tilted and opens to the left in the shape of a "П", including an upper brake disc tensioning mechanism, a middle tensioning height adjustment mechanism, a lower brake disc horizontal movement mechanism, and a disc tensioning operation mechanism on one side of the middle part.

[0010] The brake disc tensioning mechanism includes a pair of bow-shaped hub brake discs, a brake disc support, a linkage mechanism, and a brake operating mechanism. Rubber brake pads are fixed to the outer circumferential surface of the bow-shaped hub brake discs. The brake disc support is a stepped shaft structure with one end being a disc and the other end being a horizontal shaft; the outer side of the disc has a countersunk hole. The end of the horizontal shaft is vertically fixed to the upper end of the tensioning height adjustment mechanism. The bow-shaped hub brake discs have a pair of arc-shaped grooves arranged in a figure-eight pattern in the middle, and a pair of sliding screws pass through these grooves. The arc-shaped groove is screwed into the outer side of the disc; the linkage mechanism includes a first link and a second link, the upper ends of the first link and the upper ends of the second link are respectively hinged to the upper part of their respective bow-shaped hub brake discs, the second link is Z-shaped in side view, the lower end of the first link is hinged to the middle part of the second link to form a "y" shape, and the lower end of the second link is equipped with a brake cable screw; the two ends of the tension spring are respectively inserted into the upper part of the bow-shaped hub brake disc, and the lower end of the bow-shaped hub brake disc is respectively hinged to the disc through a hinge pin fixed to the lower part of the countersunk hole of the disc;

[0011] The tensioning height adjustment mechanism includes a rectangular sliding sleeve and a lower vertical shaft. One end of the horizontal shaft of the brake disc support is vertically and fixedly connected to the upper end of the rectangular sliding sleeve. The upper end of the lower vertical shaft is clearance-fitted with the lower blind hole of the rectangular sliding sleeve. The rectangular sliding sleeve is locked at the required height position by the hand-tightening screw outside the lower end of the rectangular sliding sleeve. The bottom of the lower vertical shaft is fixed to the outer end of the brake disc horizontal movement mechanism.

[0012] The brake disc horizontal movement mechanism includes a horizontal rectangular tube, a rectangular shaft, and a horizontal rectangular tube movement locking mechanism. One end of the rectangular shaft is vertically welded to the lower part of the V-shaped support seat, and the rectangular shaft and the horizontal rectangular tube are clearance-fitted. The horizontal rectangular tube movement locking mechanism includes a pressure plate, a pressure plate hinge seat, and a torsion spring. The lower end of the pressure plate hinge seat is fixed to the upper end of the horizontal rectangular tube. Multiple rectangular horizontal grooves are evenly distributed on the upper side of the rectangular shaft. The middle part of the pressure plate is hinged to the upper part of the pressure plate hinge seat. The lower end of the pressure plate passes through the window hole of the horizontal rectangular tube outside one end of the pressure plate hinge seat and is embedded in the corresponding rectangular horizontal groove on the upper side of the rectangular shaft, thereby positioning the horizontal rectangular tube in the required position. The connection position between the horizontal rectangular tube and the rectangular shaft is locked by a hand-tightening screw at one end of the horizontal rectangular tube. The middle part of the cylindrical pin of the horizontal rectangular tube passes through one end of the torsion spring, and the ends of the cylindrical pin are riveted and fixed to the lower parts of both sides of the pressure plate hinge seat. The two feet of the torsion spring abut against the lower side of the pressure plate and the upper side of the horizontal rectangular tube, respectively.

[0013] The brake operating mechanism includes an operating handle, a half-ratchet, a pawl, a brake cable mounting seat, and a brake cable with a sleeve. The upper and lower ends of the half-ratchet are respectively fixed to the middle of the outer side of a rectangular sliding sleeve. One end of the operating handle extends into the inclined groove on the upper outer side of the rectangular sliding sleeve and is hinged to the rectangular sliding sleeve. The middle part of the pawl is hinged to the middle part of the operating handle, and one end of the pawl is embedded in the groove of the half-ratchet to lock the operating handle. The lower end of the brake cable with a sleeve is connected to one end of the lower fixing pin of the brake cable screw, and the other end of the lower fixing pin is fixed to one end of the operating handle, located between the hinge point of one end of the operating handle and the hinge point of the middle part of the pawl. The upper end of the brake cable with a sleeve passes through the brake cable mounting seat and the disc fixed on the upper outer side of the rectangular sliding sleeve and is then fixed to the brake cable screw at the lower end of the second connecting rod. The two ends of the operating handle tension spring are respectively hooked to the middle part of the pawl and the middle part of the operating handle.

[0014] Furthermore, the vertical fine-tuning mechanism includes a motor-reducer assembly, a rectangular seat, a lead screw, a radial ball bearing, a thrust ball bearing, and a guide block. The bottom of the motor-reducer assembly is fixed to the top of the rectangular seat via a mounting base plate. The output shaft of the motor-reducer assembly is fixedly connected to the upper end of the lead screw. The upper part of the lead screw is supported in the upper countersunk hole of the rectangular seat via radial ball bearings and thrust ball bearings in sequence. The lower end of the lead screw is screwed into the upper threaded hole of the vertical rod. The guide block is embedded in the guide groove on the lower side of one side of the rectangular seat, and one side of the guide block is fixed in the countersunk hole on the upper side of one side of the lead screw. One end of the boom is welded and fixed to the upper side of the rectangular seat, and the motor control switch is fixed to the lower outer side of the rectangular sleeve.

[0015] Furthermore, the lower ends of the two adjacent planes of the pair of bow-shaped hub brake discs are respectively provided with chamfers of 8-10mm × 45°, and the distance between the two adjacent planes is D = 10-12mm.

[0016] This invention employs a piston pin support assembly to support the piston pin. Through the Z-axis and X-axis movement adjustment of the tension height adjustment mechanism and the brake disc horizontal movement mechanism, a pair of bow-shaped hub-type brake discs of the piston pin center hole tensioning mechanism are accurately inserted into the piston pin center hole. Then, by operating the brake operating mechanism, the pair of bow-shaped hub-type brake discs open and tighten at one end of the piston pin center hole, thereby restricting all six degrees of freedom of the piston pin. Next, by operating the piston pin axial swing mechanism and the vertical fine-tuning mechanism, the spatial position of the piston pin is further adjusted. After aligning the piston pin with the piston pin hole, it is pushed into the piston pin hole to complete the installation. This invention is simple to operate and convenient to use. Except for using a crane to hold the invention and the piston pin fixed by it, only one person is needed to complete the piston pin installation, significantly improving the installation efficiency and effectively ensuring the assembly safety of the piston pin.

[0017] The advantages and features of this utility model will be illustrated and explained through the following non-limiting description of preferred embodiments, which are given by way of example only with reference to the accompanying drawings. Attached Figure Description

[0018] Figure 1 This is the front view of this utility model;

[0019] Figure 2 yes Figure 1 The left view;

[0020] Figure 3 This is a schematic diagram showing how the piston pin is rotated to an inclined state using the piston pin axial swing mechanism of this utility model.

[0021] Figure 4 yes Figure 1 Enlarged view of Part I;

[0022] Figure 5 yes Figure 2 Enlarged view of Part II;

[0023] Figure 6 yes Figure 5 AA section view;

[0024] Figure 7 yes Figure 2 A magnified view from direction B. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] like Figures 1 to 7 As shown, this utility model includes a lifting rod mechanism 1, a piston pin support assembly 2, a piston pin axial swing mechanism 3, and a piston pin center hole tightening mechanism 4. The lifting rod mechanism 1 includes a vertical rod 11, a vertical fine-tuning mechanism 12, and a lifting arm assembly 13. The lifting arm assembly 13 includes a lifting arm 131 and a lifting eye bolt 132. The left end of the lifting arm 131 is vertically welded to the middle of the vertical fine-tuning mechanism 12. The middle of the longitudinal direction of the lifting arm 131 is provided with a waist-shaped groove 133 that runs vertically through it. The lifting eye bolt 131 passes vertically downward through the waist-shaped groove 133 and is clamped and fixed to the lifting arm 131 by a nut 134. This structure facilitates the movement of the lifting eye bolt 131 to adjust the position of the lifting plumb line, making it as close as possible to the center of gravity of the piston pin 100, thus ensuring lifting safety.

[0027] The lower end of the vertical fine-tuning mechanism 12 is connected to the upper end of the vertical rod 11, and the lower end of the vertical rod 11 is fixedly connected to the left end of the horizontally arranged piston pin axial swing mechanism 3. The piston pin support assembly 2 includes a V-shaped support seat 21 with an included angle of 90° and a pair of nylon pads 22 symmetrically fixed inside the V-shaped support seat 21. The V-shaped support seat 21 intersects the piston pin axial swing mechanism 3 perpendicularly, and the bottom center of the V-shaped support seat 21 is provided with an inverted U-shaped groove 211, which is welded and fixed to the middle of the piston pin axial swing mechanism 3. The piston pin 100 is supported on the nylon pads 22 inside the V-shaped support seat 21. The upper end of the piston pin center hole tightening mechanism 4 extends into the right end of the piston pin center hole 101 and is tightened and fixedly connected to the piston pin center hole 101. The lower end of the piston pin center hole tightening mechanism 4 is vertically fixedly connected to the middle of the piston pin axial swing mechanism 3.

[0028] like Figure 1 , 2 As shown in Figures 4 and 5, the piston pin axial swing mechanism 3 includes a fixed shaft 31, a bushing 32, a dovetail block 33, and a limiting rod 34. The fixed shaft 31 has an axial dovetail groove 311 on its upper side, and the dovetail block 33 is embedded in the axial dovetail groove 311. The arc-shaped surface of the left end of the bushing 32 abuts against the lower right end of the vertical shaft 11. The fixed shaft 31 is inserted into the bushing 32. The left end of the fixed shaft 31 is vertically fixed to the lower end of the vertical shaft 11 by a screw 35. After the right end of the fixed shaft 31 passes through the right end of the bushing 32, it is limited by a shaft retaining ring 36. Figure 2 and Figure 7 As shown, the upper side of the bushing 32 near the vertical rod 11 has a groove 321 that is a combination of a right trapezoid when viewed from the side and a triangle and a rectangle when viewed from the top. The lower end of the limiting rod 34 is fixed in the dovetail block 32, and the upper end of the limiting rod 33 extends out of the groove 321. The bottom of both sides of the groove 321 is higher than the horizontal center line of the bushing 32. The swing angle α of the limiting rod 33 is ≤110°.

[0029] like Figure 4 As shown, the piston pin center hole tensioning mechanism 4 is tilted and opens to the left in the shape of a "П". It includes an upper brake disc tensioning mechanism 41, a middle tensioning height adjustment mechanism 42, a lower brake disc horizontal movement mechanism 43, and a disc tensioning operation mechanism 44 on one side of the middle.

[0030] like Figure 4 , Figure 5 and Figure 6As shown, the brake disc tensioning mechanism 41 includes a pair of bow-shaped hub brake discs 411, a brake disc support 412, a linkage mechanism 413, and a brake operating mechanism 414. Rubber brake pads 415 are fixed to the outer circumferential surface of the bow-shaped hub brake discs 411. The brake disc support 412 is a stepped shaft structure with a disc 4121 on the left end and a horizontal shaft 4122 on the other end. The outer side of the disc 4121 is provided with a countersunk hole 4123. The end of the horizontal shaft 4122 is vertically fixed to the upper end of the tensioning height adjustment mechanism 42. The middle part of the bow-shaped hub brake discs 411 is provided with a pair of arc-shaped grooves 4111 arranged in a figure-eight shape. A pair of sliding screws 416 pass through the arc-shaped grooves 4111 and are screwed into the outer side of the disc 4121.

[0031] The linkage mechanism 413 includes a first link 4131 and a second link 4132. The upper ends of the first link 4131 and the second link 4132 are respectively hinged to the upper part of their respective bow-shaped hub brake discs 411. The second link 4132 has a Z-shaped profile in side view. The lower end of the first link 4131 is hinged to the middle part of the second link 4132 in a "Y" shape. A brake cable screw 45 is installed at the lower end of the second link 4132. The two ends of the tension spring 46 are respectively inserted into the upper part of the bow-shaped hub brake disc 411. The lower ends of the bow-shaped hub brake disc 411 are respectively hinged to the disc 4121 through hinge pins 46 fixed to the lower part of the countersunk hole 4121 of the disc 4121.

[0032] like Figure 4 As shown, the tensioning height adjustment mechanism 42 includes a rectangular sliding sleeve 421 and a lower vertical shaft 422. The right end of the horizontal shaft 4121 of the brake disc support 412 is vertically fixed to the upper end of the rectangular sliding sleeve 421. The upper end of the lower vertical shaft 422 is clearance-fitted with the lower blind hole 4211 of the rectangular sliding sleeve 421. The rectangular sliding sleeve 421 is locked at the required height position by the hand-tightening screw 423 on the lower end of the rectangular sliding sleeve 421. The bottom of the lower vertical shaft 422 is welded and fixed to the outer end of the brake disc horizontal moving mechanism 43.

[0033] The brake disc horizontal movement mechanism 43 includes a horizontal rectangular tube 431, a rectangular shaft 432 and a horizontal rectangular tube movement locking mechanism 443. The left end of the rectangular shaft 432 is vertically welded to the lower part of the V-shaped support seat 21, and the rectangular shaft 432 and the horizontal rectangular tube 431 are in clearance fit.

[0034] The horizontal rectangular tube moving locking mechanism 444 includes a pressure plate 4441, a pressure plate hinge seat 4442, and a torsion spring 4443. The lower end of the pressure plate hinge seat 4442 is fixed to the upper left end of the horizontal rectangular tube 431. Multiple rectangular transverse grooves 4321 arranged at intervals are evenly distributed on the upper side of the rectangular shaft 432. The middle part of the pressure plate 4441 is hinged to the upper part of the pressure plate hinge seat 4442. The lower end of the pressure plate 4441 passes through the horizontal rectangular tube window hole 4311 outside the right end of the pressure plate hinge seat 4442 and is then embedded in the upper side of the rectangular shaft 432. The horizontal rectangular tube 431 is positioned in the rectangular groove 4321, and the connection between the horizontal rectangular tube 431 and the rectangular shaft 432 is locked by the hand screw 423 at the left end of the horizontal rectangular tube 431; the middle part of the cylindrical pin 4444 of the horizontal rectangular tube passes through the right end of the torsion spring 433, and the ends of the cylindrical pin 4444 are respectively riveted and fixed on the lower part of both sides of the pressure plate hinge seat 4442, and the two feet of the torsion spring 4443 abut against the lower side of the pressure plate 4441 and the upper side of the horizontal rectangular tube 431 respectively.

[0035] The brake operating mechanism 414 includes an operating handle 4141, a half-ratchet 4142, a pawl 4143, a brake cable mounting seat 4144, and a brake cable with a sleeve 4145. The upper and lower ends of the half-ratchet 4142 are respectively fixed to the middle of the outer side of the rectangular sliding sleeve 421. The left end of the operating handle 4141 extends into the inclined groove 4211 on the upper outer side of the rectangular sliding sleeve 421 and is hinged to the rectangular sliding sleeve 421. The middle part of the pawl 4143 is hinged to the middle part of the operating handle 4141, and the left end of the pawl 4143 is embedded in the groove of the half-ratchet 4142 to lock the operating handle 4141. The lower end of the brake cable with a sleeve 4145 is connected to one end of a lower fixing pin 4146, and the other end of the lower fixing pin 4146 is fixed to the left end of the operating handle 4141 and is located between the hinge point of the left end of the operating handle 4141 and the hinge point of the middle part of the pawl 4143. The upper end of the sleeved brake cable 4145 passes through the brake cable mounting seat 4144 and the disc 4121 fixed on the upper outer side of the rectangular sliding sleeve 421 and is then fixed to the brake cable screw 45 at the lower end of the second connecting rod 4132. The two ends of the operating handle tension spring 4147 are hooked on the middle of the pawl 4143 and the middle of the operating handle 4141, respectively.

[0036] like Figure 1 As shown, the vertical fine-tuning mechanism 12 includes a motor-reducer assembly 121, a rectangular seat 122, a lead screw 123, a radial ball bearing 124, a thrust ball bearing 125, and a guide block 126. The bottom of the motor-reducer assembly 121 is fixed to the top of the rectangular seat 122 via a mounting base plate 127. The motor-reducer assembly 121 is connected to the upper end of the lead screw 123 via a hexagonal hole shaft. The upper part of the lead screw 123 is supported in the upper countersunk hole 1221 of the rectangular seat 122 by the radial ball bearing 124 and the thrust ball bearing 125 in sequence. The lower end of the lead screw 123 is screwed into the upper threaded hole 111 of the vertical rod 11. Figure 1In the middle, the guide block 126 is embedded in the guide groove 1221 on the lower left side of the rectangular seat 122, and the right side of the guide block 126 is fixed to the upper left side of the lead screw 123. The left end of the boom 131 is welded and fixed to... Figure 2 The upper right side of the rectangular base 122 is located on the upper part. The motor control switch 128 is fixed on the lower outer side of the rectangular sliding sleeve 421. The motor control switch 128 is connected to the motor 1211 of the motor-reducer assembly 121 via wire 128. In this embodiment, the motor has a rated voltage of 220V, a rated power of 120W, a rated speed of 75r / min, and a maximum output torque of 12.4Nm. When used to install the piston pin 100 of a large marine engine with a cylinder diameter of 320mm, the motor 1211 of the vertical fine-tuning mechanism 12 can meet the installation requirements. The motor control switch has three functions: forward rotation, reverse rotation, and stop, so as to precisely control the vertical position of the piston pin 100.

[0037] like Figure 5 As shown, the lower ends of the two adjacent planes 4112 of a pair of bow-shaped hub brake discs 411 are respectively provided with chamfers 4113 of 8-10mm × 45°, and the distance D between the two adjacent planes 4112 is 10-12mm. This structure facilitates the opening and closing of the pair of bow-shaped hub brake discs 411, thereby realizing the tightening or loosening of the pair of bow-shaped hub brake discs 411 relative to the piston pin center hole 101.

[0038] The working process of this utility model is as follows:

[0039] 1) Loosen the nut 134 on the lower end of the eye bolt 132, move the eye bolt 132 so that the axis of the eye bolt 132 is aligned with the ridge line at the bottom of the V-shaped support 21, so that the lifting plumb line is as close as possible to the center of gravity of the piston pin 100 to be lifted. Tighten the nut 134 to lock the eye bolt 132 in the position of the boom 1, and complete the lifting of the eye bolt 132 to ensure the safety of the lifting.

[0040] 2) The hook of one crane pulls the lifting shackle 20, which is installed on the lifting eye screw 132 of this utility model, upward through the lifting cable 10, pulling this utility model from a horizontal lying position to a vertical standing position and maintaining it in a vertical standing position. Another cantilever crane or other simple crane in the workshop passes the sling through the piston pin center hole 101 and hooks it on the hook, then lifts the horizontal piston pin 100 onto a pair of nylon pads 22 in the V-shaped support 21, and finally unties the sling, completing the lifting of the piston pin 100.

[0041] 3) First loosen the hand screw 423 of the tension height adjustment mechanism 42, then pull up the rectangular sleeve 421. The brake disc support 412 moves up so that a pair of bow-shaped hub brake discs 411 are aligned with the piston pin center hole 101. Then tighten the hand screw 423 to lock the rectangular sleeve 421.

[0042] Loosen the hand screw 423 of the brake disc horizontal movement mechanism 43, press down the pressure plate 4441 of the horizontal rectangular tube movement locking mechanism 444. The lower end of the pressure plate 4441 disengages from the rectangular transverse groove 4321 on the upper side of the rectangular shaft 432. Then push the rectangular shaft 432 to the left, so that a pair of bow-shaped hub brake discs 411 enter the piston pin center hole 101 until the distance L between the right side of the pair of bow-shaped hub brake discs 411 and the right end face of the piston pin 100 is 15-20mm. Next, release the pressure plate 4441. Under the action of the return force of the torsion spring 4443, the pressure plate 4441 rotates clockwise around the hinge center. The lower end of the pressure plate 4441 is engaged in the corresponding rectangular transverse groove 4321 on the upper side of the rectangular shaft 432. Finally, tighten the hand screw 423 to lock the rectangular shaft 432, completing the horizontal leftward movement of the pair of bow-shaped hub brake discs 411.

[0043] 4) First, press down the right end of the pawl 4143 of the brake operating mechanism 414. The left end of the pawl 4143 disengages from the half ratchet 4142, and the operating handle 4141 is unlocked. Then, press down the operating handle 4141 and pull one end of the sleeve brake cable 4145, so that the other end of the sleeve brake cable 4145 pulls the second link 4132. This causes the second link 4132 to drive the first link 4131 to overcome the tension of the tension spring 46, and push the pair of sliding screws 416 of the bow-shaped hub brake disc 411 to rotate outward synchronously around the center of their respective hinge pins 46 under the guidance of the arc groove 4111. The rubber brake pads 415 on the outside of the pair of bow-shaped hub brake discs 411 press against the center hole 101 of the piston pin, increasing the static friction between the pair of bow-shaped hub brake discs 411 and the hole wall of the center hole 101 of the piston pin, thus completing the tightening connection between the pair of bow-shaped hub brake discs 411 and the piston pin 100.

[0044] 5) A crane lifts the present invention and piston pin 100 onto the work platform, bringing piston pin 100 close to the piston pin hole of the piston on the work platform. If there is a height difference between the axis of piston pin 100 and the axis of piston pin hole, the assembly fitter presses the forward or reverse switch of the motor control switch 128. The vertical rod 11 drives the piston pin support assembly 2 and the piston pin 100 it carries to rise or fall, thereby aligning piston pin 100 with piston pin hole.

[0045] If the axis of piston pin 100 intersects the axis of piston pin hole, the assembly fitter will push the limiting rod 34 of the piston pin axial swing mechanism 3 to rotate, which in turn drives the fixed shaft 31 to rotate via the dovetail block 33. This causes the piston pin support assembly 2 and the piston pin center hole tightening mechanism 4 to rotate around the fixed shaft 31, tilting the axis of piston pin 100 and eliminating the intersection angle between the axis of piston pin 100 and piston pin hole. This allows one end of piston pin 100 to be pushed into the piston pin hole.

[0046] 6) First, press the right end of the pawl 4143 of the brake operating mechanism 414. The left end of the pawl 4143 disengages from the half ratchet 4142, and the operating handle 4141 is unlocked. Under the restoring force of the tension spring 46, the sleeve brake cable 4145 is released. The pair of sliding screws 416 of the pair of bow-shaped hub brake discs 411 rotate synchronously inward around the center of their respective hinge pins 46 under the guidance of the arc groove 4111. The rubber brake pads 415 on the outside of the pair of bow-shaped hub brake discs 411 disengage from the piston pin center hole 101, and the piston pin 100 is unlocked. Loosen the hand screw 423 of the brake disc horizontal movement mechanism 43, press down the pressure plate 4441 of the horizontal rectangular tube movement locking mechanism 444. The lower end of the pressure plate 4441 disengages from the rectangular transverse groove 4321 on the upper side of the rectangular shaft 432. Then pull the rectangular shaft 432 to the right, causing the pair of bow-shaped hub brake discs 411 to move to the right and disengage from the piston pin center hole 101. Finally, tighten the hand screw 423 to lock the outwardly moved rectangular shaft 432, completing the horizontal leftward movement of the pair of bow-shaped hub brake discs 411. After the piston pin 100 is unlocked, it can be hammered into the piston pin hole to complete the installation of the piston pin 100.

[0047] In addition to the above embodiments, the present invention may have other implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A piston pin mounting fixture for a large marine engine, characterized in that, The system includes a boom mechanism, a piston pin support assembly, a piston pin axial swing mechanism, and a piston pin center hole tightening mechanism. The boom mechanism comprises a vertical rod, a vertical fine-tuning mechanism, a piston pin axial swing mechanism, and a boom assembly. The boom assembly includes a boom and a lifting eye bolt. One end of the boom is vertically welded to the middle of the vertical fine-tuning mechanism. The boom has a through-groove groove in its longitudinal middle section. The lifting eye bolt passes vertically downward through the through-groove and is fixed to the boom by a nut. The lower end of the vertical fine-tuning mechanism is connected to the upper end of the vertical rod, and the lower end of the vertical rod is fixedly connected to one end of the horizontally positioned piston pin axial swing mechanism. The piston pin support assembly includes a V-shaped support seat with an included angle of 90° and a pair of nylon pads symmetrically fixed inside the V-shaped support seat. The V-shaped support seat intersects perpendicularly with the piston pin axial swing mechanism. The bottom center of the V-shaped support seat is provided with an inverted U-shaped groove, which is welded and fixed to the middle of the piston pin axial swing mechanism. The piston pin is supported on the nylon pads inside the V-shaped support seat. The upper end of the piston pin center hole tightening mechanism extends into one end of the piston pin center hole and is tightened and fixedly connected to the piston pin center hole. The lower end of the piston pin center hole tightening mechanism is perpendicularly fixedly connected to the middle of the piston pin axial swing mechanism.

2. The large marine engine piston pin installation fixture as described in claim 1, characterized in that, The piston pin axial swing mechanism includes a fixed shaft, a bushing, a dovetail block, and a limiting rod. The fixed shaft has an axial dovetail groove on its upper side, and the dovetail block is embedded in the axial dovetail groove. The arc-shaped surface of one end of the bushing abuts against the lower end of one side of the vertical shaft. The fixed shaft is inserted into the bushing, and one end of the fixed shaft is vertically and fixedly connected to the lower end of the vertical shaft. The other end of the fixed shaft passes through the other end of the bushing and is limited by a shaft retaining ring. The upper side of the bushing near the vertical rod has a groove that is a combination of a right trapezoid when viewed from the side and a triangle and a rectangle when viewed from the top. The lower end of the limiting rod is fixed in the dovetail block, and the upper end of the limiting rod extends out of the groove. The bottom of both sides of the groove is higher than the horizontal center line of the bushing.

3. The large marine engine piston pin installation fixture as described in claim 2, characterized in that, The swing angle α of the limiting rod is ≤110°.

4. The large marine engine piston pin installation fixture as described in claim 1, characterized in that, The piston pin center hole tightening mechanism is tilted and opens to the left in the shape of "П". It includes an upper brake disc tightening mechanism, a middle tightening height adjustment mechanism, a lower brake disc horizontal movement mechanism, and a disc tightening operation mechanism on one side of the middle. The brake disc tensioning mechanism includes a pair of bow-shaped hub brake discs, a brake disc support, a linkage mechanism, and a brake operating mechanism. Rubber brake pads are fixed to the outer circumferential surface of the bow-shaped hub brake discs. The brake disc support is a stepped shaft structure with one end being a disc and the other end being a horizontal shaft; the outer side of the disc has a countersunk hole. The end of the horizontal shaft is vertically fixed to the upper end of the tensioning height adjustment mechanism. The bow-shaped hub brake discs have a pair of arc-shaped grooves arranged in a figure-eight pattern in the middle, and a pair of sliding screws pass through these grooves. The arc-shaped groove is screwed into the outer side of the disc; the linkage mechanism includes a first link and a second link, the upper ends of the first link and the upper ends of the second link are respectively hinged to the upper part of their respective bow-shaped hub brake discs, the second link is Z-shaped in side view, the lower end of the first link is hinged to the middle part of the second link in a "y" shape, and the lower end of the second link is equipped with a brake cable screw; the two ends of the tension spring are respectively inserted into the upper part of the bow-shaped hub brake disc, and the lower end of the bow-shaped hub brake disc is respectively hinged to the disc through a hinge pin fixed to the lower part of the countersunk hole of the disc; The tensioning height adjustment mechanism includes a rectangular sliding sleeve and a lower vertical shaft. One end of the horizontal shaft of the brake disc support is vertically and fixedly connected to the upper end of the rectangular sliding sleeve. The upper end of the lower vertical shaft is clearance-fitted with the lower blind hole of the rectangular sliding sleeve. The rectangular sliding sleeve is locked at the required height position by the hand-tightening screw outside the lower end of the rectangular sliding sleeve. The bottom of the lower vertical shaft is fixed to the outer end of the brake disc horizontal movement mechanism. The brake disc horizontal movement mechanism includes a horizontal rectangular tube, a rectangular shaft, and a horizontal rectangular tube movement locking mechanism. One end of the rectangular shaft is vertically welded to the lower part of the V-shaped support seat, and the rectangular shaft and the horizontal rectangular tube are clearance-fitted. The horizontal rectangular tube movement locking mechanism includes a pressure plate, a pressure plate hinge seat, and a torsion spring. The lower end of the pressure plate hinge seat is fixed to the upper end of the horizontal rectangular tube. Multiple rectangular horizontal grooves are evenly distributed on the upper side of the rectangular shaft. The middle part of the pressure plate is hinged to the upper part of the pressure plate hinge seat. The lower end of the pressure plate passes through the window hole of the horizontal rectangular tube outside one end of the pressure plate hinge seat and is embedded in the corresponding rectangular horizontal groove on the upper side of the rectangular shaft, thereby positioning the horizontal rectangular tube in the required position. The connection position between the horizontal rectangular tube and the rectangular shaft is locked by a hand-tightening screw at one end of the horizontal rectangular tube. The middle part of the cylindrical pin of the horizontal rectangular tube passes through one end of the torsion spring, and the ends of the cylindrical pin are riveted and fixed to the lower parts of both sides of the pressure plate hinge seat. The two feet of the torsion spring abut against the lower side of the pressure plate and the upper side of the horizontal rectangular tube, respectively. The brake operating mechanism includes an operating handle, a half-ratchet, a pawl, a brake cable mounting seat, and a brake cable with a sleeve. The upper and lower ends of the half-ratchet are respectively fixed to the middle of the outer side of a rectangular sliding sleeve. One end of the operating handle extends into the inclined groove on the upper side of the rectangular sliding sleeve and is hinged to the rectangular sliding sleeve. The middle part of the pawl is hinged to the middle part of the operating handle, and one end of the pawl is embedded in the groove of the half-ratchet to lock the operating handle. The lower end of the brake cable with a sleeve is connected to one end of a lower fixing pin, and the other end of the lower fixing pin is fixed to one end of the operating handle, located between the hinge point of the operating handle and the hinge point of the middle part of the pawl. The upper end of the brake cable with a sleeve passes through the brake cable mounting seat and the disc fixed on the upper side of the rectangular sliding sleeve and is then fixed to the brake cable screw at the lower end of the second connecting rod. The two ends of the operating handle tension spring are respectively hooked to the middle part of the pawl and the middle part of the operating handle.

5. The large marine engine piston pin installation fixture as described in claim 1, characterized in that, The vertical fine-tuning mechanism includes a motor-reducer assembly, a rectangular base, a lead screw, a radial ball bearing, a thrust ball bearing, and a guide block. The bottom of the motor-reducer assembly is fixed to the top of the rectangular base via a mounting base plate. The output shaft of the motor-reducer assembly is fixedly connected to the upper end of the lead screw. The upper part of the lead screw is supported in the upper countersunk hole of the rectangular base by radial ball bearings and thrust ball bearings in sequence. The lower end of the lead screw is screwed into the upper threaded hole of the vertical rod. The guide block is embedded in the guide groove on the lower side of one side of the rectangular base, and one side of the guide block is fixed to the upper end of one side of the lead screw. One end of the boom is welded and fixed to the upper side of the rectangular base, and the motor control switch is fixed to the lower outer side of the rectangular sliding sleeve.

6. The large marine engine piston pin installation fixture as described in claim 1, characterized in that, A pair of bow-shaped hub brake discs have chamfers of 8-10mm × 45° at the lower ends of two adjacent planes, and the distance between the two adjacent planes is D = 10-12mm.

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