Large crankshaft connecting rod neck follow-up polishing device

Abstract

The utility model provides a large crankshaft connecting rod neck follow-up polishing device, and belongs to the technical field of machining. Comprising a machine tool body, a crankshaft and a connecting rod neck follow-up polishing device, the connecting rod neck follow-up polishing device comprises an abrasive belt, a pulley block, a steel wire traction rope, a balance weight, an abrasive belt fixing assembly and a pulley support. The abrasive belt surrounds the crankshaft connecting rod neck and is connected with one end of the steel wire traction rope through the abrasive belt fixing assembly, the pulley support is fixed to the lathe tool turret, the pulley blocks are distributed on the pulley support, the steel wire traction rope bypasses the pulley blocks, and the other end of the steel wire traction rope is connected with the balance weight. The large crankshaft connecting rod neck polishing device solves the problems that a large crankshaft connecting rod neck is large in polishing difficulty and low in machining efficiency, is compact in structure and good in stability, can finish polishing of different connecting rod necks under one-time clamping, and does not need to design an eccentric tool.

Description

Technical Field

[0001] This utility model belongs to the field of machining technology, specifically relating to a large crankshaft connecting rod neck follower polishing device. Background Technology

[0002] The crankshaft is a core component of an engine, responsible for power output. It collects the work done by the combustion gases in all the cylinders, converts the reciprocating motion of the piston into rotational motion, and transmits power to other components. Due to the harsh working environment, large crankshafts require extremely high machining precision for their main journals and connecting rod journals. Typically, the diameter tolerance grade is IT5 to IT6, and the surface roughness requirement is ≤Ra0.4.

[0003] Currently, small and medium-sized crankshafts can be machined using specialized follow-up grinding machines, but large crankshafts, due to their larger size, are typically ground only on ordinary crankshaft grinding machines. The surface roughness of the journals after grinding often fails to meet requirements, necessitating subsequent polishing. The traditional polishing method involves mounting the crankshaft on a lathe, rotating it with the lathe, and manually polishing it with a fine-grit abrasive belt held by the operator. Furthermore, when machining connecting rod journals, an eccentric disc needs to be installed on the machine spindle to adjust the center position of the connecting rod journal. This method not only requires multiple installations and adjustments of the eccentric disc, increasing the operator's workload, but also makes it difficult to precisely control the polishing force, resulting in long polishing cycles, low efficiency, and poor dimensional consistency.

[0004] In the existing technology, there is a lack of a dedicated device that can meet the polishing requirements of large crankshafts, resulting in low processing efficiency and difficulty in guaranteeing accuracy. Therefore, there is an urgent need for a high-efficiency device that can complete the polishing of crankshaft main journals and connecting rod journals in the same clamping position, so as to reduce clamping errors and improve processing accuracy and efficiency. Utility Model Content

[0005] The technical problem solved by this utility model is to provide a large crankshaft connecting rod journal follow-up polishing device. The purpose of this utility model is to solve the problems of high difficulty and low processing efficiency in polishing large crankshaft connecting rod journals. A follow-up polishing device with a compact structure and good stability is designed, which can complete the polishing of different connecting rod journals in one clamping and does not require the design of eccentric tooling.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A large crankshaft and connecting rod journal follow-up polishing device includes a machine tool body, a crankshaft and connecting rod journal follow-up polishing device mounted on the machine tool body;

[0008] The connecting rod journal follow-up polishing device includes an abrasive belt, a pulley block, a steel wire traction rope, a counterweight, an abrasive belt fixing assembly, and a pulley bracket. The abrasive belt is wrapped around the crankshaft connecting rod journal. The abrasive belt is connected to one end of the steel wire traction rope through the abrasive belt fixing assembly. The pulley bracket is fixed on the lathe turret. The pulley block is distributed on the pulley bracket. The steel wire traction rope passes around the pulley block and is connected to the counterweight at the other end.

[0009] Further defining the above solution, the sanding belt fixing assembly includes a sanding belt pressure plate, a fastening nut, and a sanding belt pressure bar. The sanding belt pressure bar is inserted into the sanding belt and then installed in the sanding belt pressure plate and locked in place by the fastening nut.

[0010] Further defining the above solution, the steel wire traction rope is fixed to the counterweight via a locking assembly; the locking assembly includes a galvanized locking buckle and a galvanized steel wire U-shaped locking buckle, the steel wire traction rope is locked into a loop by the galvanized steel wire U-shaped locking buckle, and the loop is connected to the counterweight via the galvanized locking buckle.

[0011] As a further limitation of the above scheme, the pulley bracket is provided with a protective device for surrounding the pulley assembly.

[0012] Further defining the above scheme, the contact area between the sanding belt and the crankshaft connecting rod journal accounts for 30% to 50% of the shaft diameter surface.

[0013] As a further limitation of the above scheme, the pulley group includes at least two pulleys, which are respectively fixed on the pulley bracket.

[0014] Further defining the above scheme, the lathe turret includes a Z-axis fine-tuning mechanism and an X-axis feed mechanism for adjusting the spatial position of the abrasive belt.

[0015] To further define the above scheme, the weight of the counterweight is determined by calculation using the CAD / CAE multi-motion simulation solver in NX software.

[0016] Advantages of this utility model compared to the prior art:

[0017] 1. The connecting rod neck follow-up polishing device in this solution has a compact structure, good overall stability, and is suitable for the complex working environment of the workshop.

[0018] 2. The polishing device used in this solution supports four-jaw clamping of the equipment, eliminating the need for eccentric tooling. It can achieve follow-up polishing of different connecting rod necks, resulting in high processing efficiency, reduced clamping times and reference errors, and improved processing accuracy.

[0019] 3. In this design, the contact area between the sanding belt and the connecting rod journal reaches 30% to 50%, effectively ensuring the roundness and surface roughness of the journal (≤Ra0.4);

[0020] 4. This solution achieves precise control of polishing force through a counterweight system, thereby improving polishing efficiency;

[0021] 5. The protective cover design in this plan ensures operational safety and avoids personal injury or workpiece damage caused by sanding belt breakage or steel wire traction rope ejection.

[0022] 6. This solution is applicable to large crankshafts of different sizes and has strong versatility. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a certain type of crankshaft polishing structure according to this utility model;

[0024] Figure 2 This is a schematic diagram of the connecting rod neck follower polishing device in this utility model;

[0025] Figure 3 This utility model Figure 2 Enlarged schematic diagram of part A in the diagram;

[0026] Figure 4 This utility model Figure 2 Enlarged schematic diagram of section B in the diagram. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0028] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0030] Please see Figure 1-4 The embodiments of this utility model are described in detail below.

[0031] Example: See Figure 1 As shown, the large crankshaft connecting rod journal follow-up polishing device includes a machine tool body 1, a crankshaft 2 mounted on the machine tool body 1, and a connecting rod journal follow-up polishing device 5.

[0032] See Figure 2 As shown, the connecting rod journal follow-up polishing device 5 includes an abrasive belt 5-1, a pulley block 5-3, a steel wire traction rope 5-4, a counterweight 5-6, an abrasive belt fixing assembly, and a pulley bracket 5-11. The abrasive belt 5-1 is wrapped around the crankshaft connecting rod journal. The abrasive belt 5-1 is connected to one end of the steel wire traction rope 5-4 through the abrasive belt fixing assembly. The pulley bracket 5-11 is fixed on the lathe turret. The pulley block 5-3 is distributed on the pulley bracket 5-11. The steel wire traction rope 5-4 passes around the pulley block 5-3 and its other end is connected to the counterweight 5-6.

[0033] See Figure 3 As shown, the sanding belt fixing assembly includes a sanding belt pressure plate 5-7, a fastening nut 5-8, and a sanding belt pressure bar 5-9. The sanding belt pressure bar 5-9 is inserted into the sanding belt 5-1 and then installed in the sanding belt pressure plate 5-7 and locked and fixed by the fastening nut 5-8.

[0034] See Figure 4 As shown, the steel wire traction rope 5-4 is fixed to the counterweight 5-6 through a locking assembly; the locking assembly includes a galvanized locking buckle 5-5 and a galvanized steel wire U-shaped locking buckle 5-10, the steel wire traction rope 5-4 is locked into a ring through the galvanized steel wire U-shaped locking buckle 5-10, and the ring is connected to the counterweight 5-6 through the galvanized locking buckle 5-5.

[0035] See Figure 2 As shown, the pulley bracket 5-11 is equipped with a protective cover 5-2 to surround the pulley block 5-3, which is used to prevent the sanding belt from suddenly breaking and the steel wire traction rope from flying out and injuring people or workpieces, thus ensuring safety. In this embodiment, the protective cover is only set on the uppermost pulley that bears the main force; the other pulleys do not need to be protected because they bear less force.

[0036] Preferably, the contact area between the abrasive belt 5-1 and the crankshaft connecting rod journal accounts for 30% to 50% of the shaft diameter surface, which increases the polishing contact surface and can effectively ensure the roundness and surface roughness of the journal, and the polishing effect can reach Ra0.4.

[0037] Preferably, the pulley block 5-3 includes at least two pulleys, which are respectively fixed on the pulley bracket 5-11.

[0038] Specifically, the lathe turret includes a Z-axis fine-tuning mechanism 3 and an X-axis feed mechanism 4, used to adjust the spatial position of the sanding belt 5-1.

[0039] In operation, the crankshaft 2 is mounted on the lathe using a "grab and push" method to ensure accurate positioning. Then, the connecting rod journal follow-up polishing device 5 is installed in the lathe turret. The sanding belt 5-1 is pre-fitted onto the crankshaft connecting rod journal, the sanding belt pressure bar 5-9 is inserted into the sanding belt 5-1, and then the sanding belt pressure plate 5-7 is installed and tightened with an M16 nut 5-8. At this point, the sanding belt 5-1 will adhere tightly to the surface of the crankshaft connecting rod journal under the tension of the steel wire traction rope 5-4. The spatial position of the sanding belt is adjusted according to the actual situation using the Z-axis fine-tuning mechanism 3 and the X-axis feed mechanism 4.

[0040] After starting the lathe, the crankshaft begins to rotate clockwise at a constant speed. The connecting rod journal moves by revolving around the center of the main journal and rotating on its own axis. Because the position of the connecting rod journal is constantly changing, while the position of the abrasive belt is fixed, relative displacement and friction occur between them, thus achieving polishing. Throughout the polishing process, the abrasive belt always follows the movement of the connecting rod journal. The frictional polishing force of the abrasive belt is adjusted using counterweights.

[0041] The weight of the counterweight was calculated and determined using the CAD / CAE multi-motion simulation solver in NX software to ensure appropriate tension in the abrasive belt and prevent breakage. First, the abrasive belt was discretized in the transmission mechanism tool. Then, the motion trajectory of the abrasive belt was studied, and the dynamic response of the crankshaft-abrasive belt-counterweight system was analyzed to obtain the maximum tension and average force of the abrasive belt. Further analysis was conducted to determine whether the stress level on the abrasive belt structure exceeded the yield strength, ultimately obtaining the maximum counterweight that the abrasive belt could withstand. The position of the pulley block, the length of the abrasive belt, and the length of the steel wire traction rope in the follow-up polishing device were also calculated or simulated based on the specific dimensions of the crankshaft.

[0042] This invention features a design where, during crankshaft rotation, the connecting rod journal simultaneously revolves and rotates. The sanding belt maintains contact with the connecting rod journal via a follower device. A steel wire traction rope and counterweight system provide constant tension, ensuring uniform contact pressure between the sanding belt and the connecting rod journal surface. A pulley system and locking assembly ensure stable movement of the sanding belt, preventing deviation. A protective cover prevents the steel wire traction rope from flying out in case of breakage, ensuring operational safety. Z-axis and X-axis adjustment mechanisms precisely control the position of the sanding belt, adapting to crankshafts of different sizes. This device solves the problems of high polishing difficulty and low processing efficiency in polishing large crankshaft connecting rod journals. It has a compact structure, good stability, and can complete the polishing of different connecting rod journals in a single setup without requiring eccentric tooling.

[0043] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A large crankshaft connecting rod journal follower polishing device, characterized in that: Includes a machine tool body (1), a crankshaft (2) mounted on the machine tool body (1), and a connecting rod journal follow-up polishing device (5); The connecting rod journal follow-up polishing device (5) includes an abrasive belt (5-1), a pulley block (5-3), a steel wire traction rope (5-4), a counterweight (5-6), an abrasive belt fixing assembly, and a pulley bracket (5-11). The abrasive belt (5-1) is wrapped around the crankshaft connecting rod journal. The abrasive belt (5-1) is connected to one end of the steel wire traction rope (5-4) through the abrasive belt fixing assembly. The pulley bracket (5-11) is fixed on the lathe turret. The pulley block (5-3) is distributed on the pulley bracket (5-11). The steel wire traction rope (5-4) passes around the pulley block (5-3) and its other end is connected to the counterweight (5-6).

2. The large crankshaft connecting rod journal follower polishing device according to claim 1, characterized in that: The sanding belt fixing assembly includes a sanding belt pressure plate (5-7), a fastening nut (5-8), and a sanding belt pressure bar (5-9). The sanding belt pressure bar (5-9) is inserted into the sanding belt (5-1) and then installed in the sanding belt pressure plate (5-7) and locked and fixed by the fastening nut (5-8).

3. The large crankshaft connecting rod journal follower polishing device according to claim 1, characterized in that: The steel wire traction rope (5-4) is fixed to the counterweight (5-6) by a locking assembly; the locking assembly includes a galvanized locking buckle (5-5) and a galvanized steel wire U-shaped locking buckle (5-10). The steel wire traction rope (5-4) is locked into a ring by the galvanized steel wire U-shaped locking buckle (5-10), and the ring is connected to the counterweight (5-6) by the galvanized locking buckle (5-5).

4. The large crankshaft connecting rod journal follower polishing device according to claim 1, characterized in that: The pulley bracket (5-11) is provided with a protective device (5-2) for surrounding the pulley assembly (5-3).

5. The large crankshaft connecting rod journal follower polishing device according to claim 1, characterized in that: The contact area between the sanding belt (5-1) and the crankshaft connecting rod journal accounts for 30% to 50% of the shaft diameter surface.

6. The large crankshaft connecting rod journal follower polishing device according to claim 1, characterized in that: The pulley assembly (5-3) includes at least two pulleys, which are respectively fixed on the pulley bracket (5-11).

7. The large crankshaft connecting rod journal follower polishing device according to claim 1, characterized in that: The lathe turret includes a Z-axis fine-tuning mechanism (3) and an X-axis feed mechanism (4) for adjusting the spatial position of the abrasive belt (5-1).

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