A turning machine for finishing the crankshaft journal

Abstract

The application relates to the technical field of crankshaft turning, and discloses a turning machine tool for crankshaft connecting rod neck finishing, which comprises a turning part, the turning part comprises a workbench, a slide plate box is slidably connected to the upper surface of the workbench, a tool holder is slidably connected to the upper surface of the slide plate box, and a turning tool is fixedly installed on the upper surface of the tool holder; and a clamping part, the clamping part comprises a main shaft box. The turning machine tool for crankshaft connecting rod neck finishing can effectively solve the problem that, in the prior art, when a connecting rod neck is processed by a turning machine tool, an eccentric chuck is usually used to eccentrically install a workpiece, so that the axis of the connecting rod neck coincides with the rotation center of the main shaft of the machine tool, the eccentricity of the gravity center is balanced, a counterweight is arranged on a rotating disc, however, after the position of the eccentric chuck is adjusted, the overall gravity center of the rotating part is offset, the position of the counterweight needs to be estimated according to the size of the eccentric distance and experience, and the adjusting process is complicated.

Description

Technical Field

[0001] This invention relates to the field of crankshaft turning technology, and more specifically to a turning machine tool for finishing crankshaft connecting rod journals. Background Technology

[0002] Turning utilizes the workpiece's rotational motion as the primary motion, and the cutting tool's linear movement along the workpiece's axial or radial direction as the feed motion. Excess material is removed from the workpiece through the relative motion between the cutting tool and the workpiece. The crankshaft is a core transmission component in power machinery such as internal combustion engines, compressors, and pumps. Its structure is relatively complex, mainly composed of the main journal, connecting rod journal, and crank arm. Due to structural and functional requirements, the connecting rod journal and the main journal of the crankshaft do not coincide in axis; there is a certain eccentricity between them.

[0003] In existing technology, when machining connecting rod journals on turning machine tools, an eccentric chuck is usually used to eccentrically mount the workpiece so that the axis of the connecting rod journal coincides with the rotation center of the machine tool spindle. To balance the center of gravity shift caused by the eccentricity, a counterweight is also placed on the rotary table. However, after the position of the eccentric chuck is adjusted, the overall center of gravity of the rotating part will shift, and the operator needs to estimate the position of the counterweight based on the size of the eccentricity and experience, which is a cumbersome adjustment process. Summary of the Invention

[0004] To address the aforementioned shortcomings of existing technologies, this invention provides a turning machine tool for precision machining of crankshaft connecting rod journals. This effectively solves the problem in existing technologies where, when machining connecting rod journals, an eccentric chuck is typically used to eccentrically mount the workpiece, aligning the axis of the connecting rod journal with the rotation center of the machine tool spindle. To balance the center of gravity shift caused by this eccentricity, counterweights are placed on the rotary table. However, after adjusting the position of the eccentric chuck, the overall center of gravity of the rotating part shifts, requiring operators to estimate the position of the counterweights based on the eccentricity and experience, resulting in a cumbersome adjustment process.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a turning machine tool for finishing crankshaft connecting rod journals, comprising:

[0007] A turning section, the turning section including a worktable, a slide box slidably connected to the upper surface of the worktable, a tool holder slidably connected to the upper surface of the slide box, and a turning tool fixedly mounted on the upper surface of the tool holder;

[0008] The clamping part includes a spindle box, a rotating disk is drivenly connected to the outer surface of the spindle box, a mounting plate is slidably connected to the rotating disk through a groove on its outer surface, an eccentric chuck is fixedly connected to the outer surface of the mounting plate, a chuck claw is slidably connected to the outer side of the eccentric chuck away from the mounting plate, a through groove is opened inside the rotating disk, a counterweight block for balancing the position of the eccentric chuck is slidably connected inside the through groove, and an adjusting element is provided in the rotating disk through a receiving cavity opened inside it.

[0009] Furthermore, the upper surface of the worktable is provided with a guide rail, and two spindle boxes are provided, one of which is fixedly installed at the bottom end with the upper surface of the worktable, and the other of which is slidably connected at the bottom end with the guide rail surface.

[0010] Furthermore, the slide groove is parallel to the through groove, the adjusting member includes a gear rotatably connected to the inside of the receiving cavity, the counterweight block is fixedly connected to a gear rod one that meshes with the outer surface of the gear on the side near the receiving cavity, and the mounting plate is fitted with a gear rod two that meshes with the outer surface of the gear on the side near the gear rod one.

[0011] Furthermore, the counterweight has a central through hole in the middle, and the central through hole adopts a stepped variable diameter structure with one end larger than the other. An elastic sleeve is embedded inside the counterweight, and the elastic sleeve adopts a conical design. An adjusting rod is sleeved inside the central through hole, and the middle of the outer circumference of the adjusting rod is provided with an inclined surface that fits against the inner wall surface of the elastic sleeve.

[0012] Furthermore, the adjusting rod adopts a variable diameter structure with a large diameter section and a small diameter section centered on the inclined plane, which fits against the inner wall surface of the central through hole. The smaller diameter section of the adjusting rod has a counterweight groove, and the interior of the adjusting rod has a placement cavity that communicates with the interior of the counterweight groove. A locking element is installed inside the placement cavity.

[0013] Furthermore, the elastic sleeve is fixedly connected to an abutment block by a connecting rod embedded inside it. The outer surface of the abutment block penetrates the outer surface of the counterweight block and fits against the inner wall of the through groove. The outer surface of the elastic sleeve is provided with two sets of connecting rods and abutment blocks, which are symmetrically distributed around the elastic sleeve.

[0014] Furthermore, the locking component includes a plumb rod that slides against the inner wall of the placement cavity. A rotating rod is hinged to the inner end of the plumb rod, and a positioning block is hinged to the outer end of the rotating rod. The outer end of the positioning block penetrates the outer circumference of the adjusting rod and extends into the interior of the counterweight block. A spring is provided at the inner end of the plumb rod and connected to the inner wall of the placement cavity. A connecting arm is fixedly connected to the outer end of the plumb rod.

[0015] Furthermore, the chuck is provided with multiple jaws, and a rubber layer is fixedly installed on the side of the jaws near the axis of the eccentric chuck. The side of the rubber layer away from the jaws adopts an arc surface design that contacts the outer surface of the workpiece.

[0016] The technical solution provided by this invention has the following advantages compared with the prior art:

[0017] 1. This invention adjusts the position of the eccentric chuck by sliding the mounting plate along the groove. Simply adjusting the relative position of the eccentric chuck's shaft center by sliding the mounting plate allows for rapid switching between the coaxial reference position and the eccentric machining position. After the main journal is finished, the crankshaft workpiece remains clamped and fixed throughout the process without disassembly, tooling changes, or secondary positioning correction. It directly switches to the eccentric machining mode for the connecting rod journal, achieving integrated continuous operation for the finishing of two types of core crankshaft journals. This significantly reduces tooling change and positioning calibration time, effectively improving the overall production efficiency of crankshaft finishing.

[0018] 2. In traditional eccentric machining tools, the counterweight structure remains fixed after the eccentric chuck position is adjusted. The eccentric displacement and the centrifugal force generated by the center of gravity cannot be offset in real time. If the counterweight is not adjusted after the eccentric chuck position changes, spindle runout and tool mark vibration are likely to occur during high-speed machining, affecting the finishing quality. This invention uses a symmetrical transmission structure where gears mesh with rack one and rack two on both sides of the internal gear of the adjusting component. This allows the counterweight to synchronously move in the opposite direction during the eccentric sliding adjustment of the mounting plate. The eccentric adjustment and counterweight balancing are linked in real time and adaptively matched. Regardless of the eccentric chuck position, the eccentric torque and center of gravity difference generated by the eccentric offset can be offset in real time, maintaining the overall dynamic balance of the rotary table. This completely solves the problems of vibration and large radial runout in traditional eccentric machining, providing a stable operating foundation for high-precision crankshaft machining.

[0019] 3. This invention employs a detachable and replaceable adjusting lever, suitable for machining crankshafts of various specifications and models. The equipment boasts strong versatility and offers precise and convenient counterweight adjustment. Existing counterweight structures are mostly fixed, integral counterweight blocks with non-adjustable parameters, limiting their applicability to single-specification crankshaft machining. For machining crankshafts of different weights and eccentricities, the entire counterweight component must be replaced, resulting in cumbersome adjustments, poor applicability, and low counterweight calibration accuracy. This invention abandons the integral counterweight design, adopting a modular structure where the adjusting lever is independently and detachably inserted into the central through-hole of the counterweight block. Different weights and specifications of adjusting levers can be flexibly replaced according to the weight and eccentricity parameters of the crankshaft to be machined, without disassembling or replacing the main counterweight block structure. This makes counterweight replacement simple and quick.

[0020] 4. During the assembly process of the adjusting rod being inserted into the central through hole, the invention utilizes the circumferential expansion of the elastic sleeve by the inclined surface of the adjusting rod to simultaneously drive the abutment block to press against the inner wall of the through groove, automatically securing the counterweight block to the target working position inside the through groove without the need for additional external locking parts. Simultaneously, the locking component pops out and engages inside the counterweight block, simultaneously completing the axial and circumferential mechanical locking between the adjusting rod and the counterweight block. The entire installation process, including clamping and locking, is completed simultaneously in one step, eliminating the need for secondary locking operations. This makes assembly convenient and efficient, ensuring no slippage or movement of the counterweight block and adjusting rod during high-speed rotary turning. The counterweight's stability is strong, continuously guaranteeing a constant and reliable dynamic balance effect during eccentric finishing. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0022] Figure 1 This is a three-dimensional structural diagram of an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the clamping part according to an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the rotating disk, mounting plate, and eccentric chuck in an embodiment of the present invention;

[0025] Figure 4 This is a cross-sectional structural diagram of the rotary disk, mounting plate, and eccentric chuck according to an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the structure of the adjusting component, mounting plate, and counterweight block according to an embodiment of the present invention;

[0027] Figure 6 This is a cross-sectional structural diagram of the rotating disk, counterweight, adjusting rod, and adjusting component according to an embodiment of the present invention;

[0028] Figure 7 This is a cross-sectional structural diagram of the rotating disk, counterweight, elastic sleeve, and abutment block according to an embodiment of the present invention;

[0029] Figure 8 This is an embodiment of the present invention. Figure 7 A magnified structural diagram of part A in the middle;

[0030] Figure 9 This is a schematic diagram of the separation structure of the counterweight, elastic sleeve, and adjusting rod in an embodiment of the present invention.

[0031] The labels in the diagram represent: 1. Turning section; 11. Worktable; 12. Slide box; 13. Tool post; 14. Turning tool; 2. Clamping section; 21. Spindle box; 22. Rotary disk; 221. Slide groove; 222. Through groove; 23. Mounting plate; 24. Eccentric chuck; 241. Claw; 2411. Rubber layer; 25. Counterweight block; 251. Central through hole; 252. Elastic sleeve; 2521. Connecting rod; 2522. Abutment block; 26. Adjusting component; 261. Gear; 262. Gear rack one; 263. Gear rack two; 27. Adjusting weight rod; 271. Inclined surface; 272. Counterweight groove; 273. Placement cavity; 28. Locking component; 281. Vertical rod; 282. Rotating rod; 283. Positioning block; 284. Spring; 285. Connecting arm. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] The present invention will be further described below with reference to embodiments.

[0034] Example:

[0035] Please see Figures 1-9 This invention provides a technical solution: a turning machine tool for precision machining of crankshaft connecting rod journals, comprising:

[0036] Turning section 1 includes a worktable 11, a slide box 12 is slidably connected to the upper surface of the worktable 11, a tool holder 13 is slidably connected to the upper surface of the slide box 12, and a turning tool 14 is fixedly installed on the upper surface of the tool holder 13.

[0037] The clamping part 2 includes a spindle box 21. A rotating disk 22 is connected to the outer surface of the spindle box 21. A mounting plate 23 is slidably connected to the rotating disk 22 via a groove 221 on its outer surface. An eccentric chuck 24 is fixedly connected to the outer surface of the mounting plate 23. A chuck claw 241 is slidably connected to the outer side of the eccentric chuck 24 away from the mounting plate 23. A through groove 222 is provided inside the rotating disk 22. A counterweight 25 for balancing the position of the eccentric chuck 24 is slidably connected inside the through groove 222. An adjusting member 26 is provided in the receiving cavity provided inside the rotating disk 22.

[0038] The upper surface of the worktable 11 is provided with guide rails, and there are two spindle boxes 21. The bottom end of one spindle box 21 is fixedly installed with the upper surface of the worktable 11, and the bottom end of the other spindle box 21 is slidably connected to the surface of the guide rails.

[0039] The slide groove 221 is parallel to the through groove 222. The adjusting member 26 includes a gear 261 that is rotatably connected to the inside of the receiving cavity. The counterweight block 25 is fixedly connected to a rack 262 that meshes with the outer surface of the gear 261 on the side near the receiving cavity. The mounting plate 23 is fitted with a rack 263 that meshes with the outer surface of the gear 261 on the side near the rack 262.

[0040] The counterweight 25 has a central through hole 251 in its middle. The central through hole 251 adopts a stepped diameter structure with one end larger than the other. An elastic sleeve 252 is embedded inside the counterweight 25. The elastic sleeve 252 has a conical design. An adjusting rod 27 is fitted inside the central through hole 251. The center of the outer circumference of the adjusting rod 27 has an inclined surface 271 that fits against the inner wall surface of the elastic sleeve 252. The adjusting rod 27 of this invention adopts a diameter-variable structure design, and with the material reduction of the internal counterweight groove 272 in the thick section, the overall center of gravity of the adjusting rod 27 is kept coaxial with the center of gravity of the counterweight 25. During assembly, by controlling the vertical distance between the upper and lower ends of the adjusting rod 27 and the upper and lower end faces of the counterweight 25, the counterweight load is ensured to be evenly distributed vertically, eliminating the problems of rotational eccentricity, local stress concentration, and rotational sway caused by unilateral imbalance. With the expansion and abutment positioning of the elastic sleeve 252 and the mechanical double locking structure of the locking component 28, the weight adjustment rod 27 is not loose, shifting, or displaced after assembly. The counterweight state remains constant during long-term continuous precision machining, greatly improving the stability of equipment operation and structural durability.

[0041] The adjusting rod 27 adopts a variable diameter structure with a large diameter section and a small diameter section centered on the inclined surface 271. It fits against the inner wall surface of the central through hole 251. The smaller diameter section of the adjusting rod 27 has a counterweight groove 272. The interior of the adjusting rod 27 has a placement cavity 273 that communicates with the interior of the counterweight groove 272. A locking element 28 is installed inside the placement cavity 273.

[0042] The elastic sleeve 252 is fixedly connected to the abutment block 2522 by the connecting rod 2521 embedded inside it. The outer surface of the abutment block 2522 penetrates the outer surface of the counterweight block 25 and fits against the inner wall of the through groove 222. The outer surface of the elastic sleeve 252 is provided with two sets of connecting rods 2521 and abutment blocks 2522, which are symmetrically distributed around the elastic sleeve 252.

[0043] The locking component 28 includes a vertical rod 281, which slides against the inner wall of the placement cavity 273. The inner end of the vertical rod 281 is hinged to a rotating rod 282, and the outer end of the rotating rod 282 is hinged to a positioning block 283. The outer end of the positioning block 283 passes through the outer circumference of the adjusting rod 27 and extends into the counterweight block 25. The inner end of the vertical rod 281 is provided with a spring 284 that is connected to the inner wall of the placement cavity 273, and the outer end of the vertical rod 281 is fixedly connected to a connecting arm 285.

[0044] Multiple jaws 241 are provided. A rubber layer 2411 is fixedly installed on the side of the jaw 241 close to the axis of the eccentric chuck 24. The side of the rubber layer 2411 away from the jaw 241 adopts an arc surface design that contacts the outer surface of the workpiece.

[0045] In the initial state, the mounting plate 23 is stationary and slidably limited to the middle reference scale position of the slide groove 221. The axis of the eccentric chuck 24 is completely coincident and aligned with the axis of rotation of the rotary disk 22. The clamping part 2 has no eccentric offset, forming a standard coaxial clamping position, which is only suitable for coaxial rotary turning of crankshaft main journals. Under the synchronous counterweight balance state, the center of gravity of the counterweight block 25 slidably assembled in the through groove 222 inside the rotary disk 22 is on the same horizontal reference line as the center of gravity of the eccentric chuck 24 and the clamped workpiece. The rotary disk 22 is subjected to uniform force in the circumferential direction, and there is no risk of uneven vibration during subsequent rotation of the machine tool.

[0046] Before the adjusting rod 27 is assembled, the central through hole 251 of the stepped variable diameter structure in the middle of the counterweight block 25 remains hollow and empty, and the conical elastic sleeve 252 embedded inside the counterweight block 25 is in its natural contracted original state. When the elastic sleeve 252 contracts and resets, it will simultaneously drive the two sets of connecting rods 2521 and abutment blocks 2522 symmetrically arranged on its outer side to contract and converge towards the inner side of the center of the elastic sleeve 252, so that the outer surface of the abutment block 2522 is completely contained and hidden inside the counterweight block 25. The abutment block 2522 does not protrude from the outer wall of the counterweight block 25, and the counterweight block 25 as a whole is in an unrestrained and freely sliding ready state inside the through groove 222, and can be flexibly moved and adjusted in conjunction with the adjusting component 26. At the same time, the slide box 12 and tool post 13 on the worktable 11 are reset to the initial feed origin position, the cutting tool 14 is moved away from the clamping position, the distance between the two spindle boxes 21 is adjusted and fixed according to the preset foundation length of the crankshaft to be processed, the chuck 241 is in the open ready state, and the whole equipment is ready for workpiece clamping.

[0047] The adjusting lever 27 is independently and detachably inserted into the central through hole 251 of the counterweight block 25. By replacing the adjusting lever 27 with different weight specifications, the machine tool can be adapted to the counterweight requirements of crankshaft precision machining of different models and different eccentric parameters, making the equipment highly versatile. The adjusting lever 27 adopts a variable diameter structure with one section thick and one section thin. The counterweight block 25 can automatically shift synchronously with the eccentric adjustment position of the mounting plate 23, dynamically offsetting the center of gravity shift and rotational centrifugal interference generated during the eccentric adjustment operation of the eccentric chuck 24. To ensure that the overall rotation after counterweight addition is free from eccentric load and the balance accuracy is constant, the overall center of gravity of the adjusting lever 27 and the center of gravity of the counterweight block 25 are always kept coaxially coincident. During assembly and installation, the vertical distance from the top end face of the adjusting lever 27 to the top end face of the counterweight block 25 is strictly controlled to be equal to the vertical distance from the bottom end face of the adjusting lever 27 to the bottom end face of the counterweight block 25, ensuring that the counterweight load is evenly distributed vertically and preventing rotational vibration caused by unilateral imbalance. Meanwhile, a counterweight groove 272 is provided inside the thick section with a larger diameter of the counterweight rod 27. Through the material reduction structure design of the counterweight groove 272, the basic counterweight value of the counterweight rod 27 itself can be precisely adjusted to further compensate for the residual imbalance after the eccentric chuck 24 switches positions, ensuring the dynamic balance operation of the machine tool throughout the eccentric turning process.

[0048] The process of installing the adjusting lever 27:

[0049] Before crankshaft clamping and machining, a corresponding weight adjustment rod 27 is selected based on the overall weight and parameters of the crankshaft to be machined. Different weight adjustment rods 27 are set with varying weights to meet the counterweight requirements of different crankshaft models. The structure of the center through hole 251 of the weight adjustment rod 27 and the counterweight block 25 is consistent, both adopting a stepped diameter structure with one end larger than the other. All assembly operations of the weight adjustment rods 27 are completed in the machine tool stopped and locked state. After stopping, the machine tool control system will automatically adjust the center through hole 251 of the counterweight block 25 so that the large diameter section faces down and the small diameter section faces up, ensuring accurate alignment of the loading and assembly. The machine tool is equipped with a dedicated loading magazine as the loading mechanism for the weight adjustment rods 27, which mainly consists of a support and a top block. The support lifts the lower end face of the large diameter section of the weight adjustment rod 27 for initial positioning, and the top block is located at the center of the support with its top end extending into the counterweight groove 272 at the end of the weight adjustment rod 27.

[0050] During the loading and assembly of the adjusting rod 27, the top block of the loading chamber rises and presses against the connecting arm 285 of the locking member 28 inside the placement cavity 273. The connecting arm 285, under pressure, causes the vertical rod 281 to slide inward along the inner wall of the placement cavity 273, simultaneously compressing the spring 284 to achieve an energy-storing compression state. The inward displacement of the vertical rod 281 causes the hinged rotating rod 282 at its end to rotate and swing. Simultaneously, the rotating rod 282 pulls the hinged positioning block 283 at its outer end inward, causing the positioning block 283 to be completely housed inside the placement cavity 273, thus releasing the positioning and blocking limit of the adjusting rod 27 assembly. Subsequently, the adjusting rod 27, with its small-diameter section as the pilot end, slowly moves upward from the large-diameter end of the central through hole 251, continuously advancing the assembly depth. During the upward movement of the adjusting rod 27, its central inclined surface 271 gradually presses against the conical inner wall of the elastic sleeve 252. Because the elastic sleeve 252 is constrained by the counterweight block 25 cavity, it can only perform a circumferential horizontal expansion. The continuous pressing of the inclined surface 271 pushes the elastic sleeve 252 outward circumferentially, simultaneously causing the connecting rod 2521 and the abutment block 2522 to move outward until the abutment block 2522 protrudes from the outer wall of the counterweight block 25 and tightly abuts against the inner wall of the through groove 222. This fixes the relative position of the counterweight block 25 and the through groove 222, preventing slippage. After assembly, the top block falls back to release force, the spring 284 rebounds and pushes the vertical rod 281 back to its original position, and the rotating rod 282 rotates in the opposite direction to push the positioning block 283 outward. The positioning block 283 inserts into the positioning groove inside the counterweight block 25, completing the mechanical rigid locking of the adjusting rod 27 and preventing loosening or movement during processing.

[0051] The crankshaft clamping and turning process:

[0052] After the adjusting lever 27 is assembled and locked, and the counterweight 25 is fixed in position, the two ends of the crankshaft to be processed are respectively placed in the inner clamping areas of the eccentric chuck 24 corresponding to the two spindle boxes 21. One of the spindle boxes 21 is driven to slide along the guide rail, and the gap between the two spindle boxes 21 gradually decreases until the center pin in the middle of the eccentric chuck 24 presses against the two ends of the crankshaft. The eccentric chuck 24 is controlled to drive multiple jaws 241 to slide synchronously towards the axis of rotation to clamp the ends of the crankshaft workpiece. The rubber layer 2411 of the inner arc surface structure of the jaws 241 is flexibly and tightly attached to the outer surface of the crankshaft workpiece, which not only increases the clamping friction to prevent the workpiece from slipping and rotating during the turning process, but also avoids the workpiece surface damage and indentation deformation caused by rigid clamping, ensuring firm clamping and no clamping damage.

[0053] After the workpiece is clamped and positioned, the machine tool starts running. The spindle box 21 drives the rotary table 22 to rotate at a constant and stable speed. The rotary table 22 synchronously drives the eccentric chuck 24 and the crankshaft workpiece clamped and fixed to rotate coaxially and synchronously, maintaining a constant rotational speed for the workpiece. Then, the turning section 1 starts operation. The slide box 12 on the worktable 11 slides laterally to adjust the total turning feed stroke, and the tool post 13 on the slide box 12 finely adjusts the tool position longitudinally, precisely controlling the cutting depth and relative cutting position of the cutting tool 14 fixed at the top of the tool post 13 with the outer circle of the crankshaft main journal. The cutting tool 14 feeds in coordination with the slide box 12 and the tool post 13, performing continuous turning and finishing on the outer circumference of the crankshaft main journal. Throughout the entire machining process, because the entire machine is in a coaxial reference initial state, the center of gravity of the counterweight 25 and the center of gravity of the clamping structure are always balanced. The rotary disk 22 rotates without eccentric centrifugal force, vibration, or jumping. The cutting tool 14 feeds smoothly without vibration, effectively ensuring that the roundness, surface finish, and dimensional accuracy of the crankshaft main journal meet the standards, and completing all finishing cutting operations of the main journal.

[0054] The process of turning the connecting rod journal in the crankshaft:

[0055] After all the crankshaft main journal turning processes are completed, the machine tool control system controls the main spindle box 21 to stop, and the rotary table 22 to stop and reset precisely. Throughout the process, the crankshaft workpiece is held in clamp without being disassembled or replaced, and the machine tool is directly switched to the eccentric finishing condition of the connecting rod journal.

[0056] First, the top block in the loading chamber lifts and presses the connecting arm 285 again. The compression spring 284 drives the positioning block 283 of the locking part 28 to retract and return to the placement cavity 273, releasing the locking constraint between the adjusting rod 27 and the counterweight block 25. The original adjusting rod 27 is then removed. After the adjusting rod 27 is removed, the inclined surface 271 releases the squeezing effect on the elastic sleeve 252. The elastic sleeve 252 elastically retracts and resets, causing the abutment block 2522 to retract and disengage from the inner wall of the through groove 222. The counterweight block 25 is released from the abutment limit and returns to a freely sliding and adjustable state.

[0057] The control system drives the mounting plate 23 to slide along the outer groove 221 of the rotary disk 22, and the mounting plate 23 drives the eccentric chuck 24 to move eccentrically in sync, changing the relative position of the eccentric chuck 24 and the rotary disk 22 until the axis of the crankshaft connecting rod journal is precisely aligned with the axis of rotation of the rotary disk 22, thus meeting the datum requirements for eccentric turning of the connecting rod journal. At the instant of the sliding adjustment of the mounting plate 23, the inner side of the mounting plate 23 toothed rod 263 synchronously displaces and meshes, driving the gear 261 of the adjusting component 26 to rotate. Toothed rod 262 and toothed rod 263 are distributed on both sides of the gear 261. Therefore, while the gear 261 rotates, it will synchronously mesh and drive toothed rod 262 to make a reverse linear motion, thereby driving the counterweight 25 to slide synchronously in the reverse direction inside the through groove 222, realizing real-time linkage between eccentric adjustment and counterweight balance. When the mounting plate 23 moves up, the counterweight 25 moves down, automatically offsetting the center of gravity shift and centrifugal force generated by the eccentric displacement, and always maintaining the dynamic balance of the rotating disk 22.

[0058] After the eccentric alignment and counterweight adjustment are completed, a counterweight rod 27 suitable for the eccentric machining of the connecting rod journal is selected. The above process of selecting the counterweight rod 27, loading, pressing, abutting and locking assembly is repeated to fix the position of the counterweight block 25 and the counterweight rod 27. The machine tool is started again, and the rotary table 22 drives the crankshaft workpiece to rotate eccentrically. The turning section 1 adjusts the feed of the cutting tool 14 to perform high-precision eccentric turning finishing operation on the crankshaft connecting rod journal. The entire process does not require disassembling the workpiece, the process is continuous and efficient, and the machining stability and finishing accuracy are greatly improved.

[0059] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A turning machine tool for precision machining of crankshaft connecting rod journals, characterized in that, include: Turning section (1), the turning section (1) includes a worktable (11), a slide box (12) is slidably connected to the upper surface of the worktable (11), a tool holder (13) is slidably connected to the upper surface of the slide box (12), and a turning tool (14) is fixedly installed on the upper surface of the tool holder (13). The clamping part (2) includes a spindle box (21). A rotating disk (22) is connected to the outer surface of the spindle box (21). A mounting plate (23) is slidably connected to the rotating disk (22) through a groove (221) on its outer surface. An eccentric chuck (24) is fixedly connected to the outer surface of the mounting plate (23). A chuck (241) is slidably connected to the outer side of the eccentric chuck (24) away from the mounting plate (23). A through groove (222) is provided inside the rotating disk (22). A counterweight (25) for balancing the position of the eccentric chuck (24) is slidably connected inside the through groove (222). An adjusting member (26) is provided in the receiving cavity provided inside the rotating disk (22).

2. The turning machine tool for precision machining of crankshaft connecting rod journals according to claim 1, characterized in that: The upper surface of the worktable (11) is provided with a guide rail, and there are two spindle boxes (21). The bottom end of one spindle box (21) is fixedly installed with the upper surface of the worktable (11), and the bottom end of the other spindle box (21) is slidably connected to the surface of the guide rail.

3. A turning machine tool for precision machining of crankshaft connecting rod journals according to claim 1, characterized in that: The slide (221) is parallel to the through groove (222). The adjusting member (26) includes a gear (261) that is rotatably connected to the inside of the receiving cavity. The counterweight (25) is fixedly connected to a rack (262) that meshes with the outer surface of the gear (261) on the side near the receiving cavity. The mounting plate (23) is fitted with a rack (263) that meshes with the outer surface of the gear (261) on the side near the rack (262).

4. A turning machine tool for finishing crankshaft connecting rod journals according to claim 3, characterized in that: The counterweight (25) has a central through hole (251) in the middle. The central through hole (251) has a stepped diameter structure. An elastic sleeve (252) is embedded inside the counterweight (25). The elastic sleeve (252) has a tapered design. An adjusting rod (27) is sleeved inside the central through hole (251). The adjusting rod (27) has a sloping surface (271) in the middle of its outer circumference that fits against the inner wall surface of the elastic sleeve (252).

5. A turning machine tool for precision machining of crankshaft connecting rod journals according to claim 4, characterized in that: The adjusting rod (27) adopts a variable diameter structure with a large diameter section and a small diameter section centered on the inclined plane (271). The section with a small diameter of the adjusting rod (27) is provided with a counterweight groove (272). The interior of the adjusting rod (27) is provided with a placement cavity (273) that communicates with the interior of the counterweight groove (272). The interior of the placement cavity (273) is provided with a locking element (28).

6. A turning machine tool for finishing crankshaft connecting rod journals according to claim 4, characterized in that: The elastic sleeve (252) is fixedly connected to the abutment block (2522) by the connecting rod (2521) embedded inside it. The outer surface of the abutment block (2522) penetrates the outer surface of the counterweight block (25) and fits against the inner wall of the through groove (222).

7. A turning machine tool for finishing crankshaft connecting rod journals according to claim 5, characterized in that: The locking component (28) includes a vertical rod (281), which slides against the inner wall of the placement cavity (273). The inner end of the vertical rod (281) is hinged to a rotating rod (282), and the outer end of the rotating rod (282) is hinged to a positioning block (283). The outer end of the positioning block (283) passes through the outer circumference of the adjusting rod (27) and extends into the counterweight block (25). The inner end of the vertical rod (281) is provided with a spring (284) connected to the inner wall of the placement cavity (273), and the outer end of the vertical rod (281) is fixedly connected to a connecting arm (285).

8. A turning machine tool for precision machining of crankshaft connecting rod journals according to claim 1, characterized in that: A rubber layer (2411) is fixedly installed on the side of the jaw (241) near the axis of the eccentric chuck (24). The side of the rubber layer (2411) away from the jaw (241) adopts an arc surface design that contacts the outer surface of the workpiece.

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