Automatic aligning and centering device and pre-tightening method for assembling crankshaft and frame

Abstract

The present application relates to diesel engine assembly technical field, provide a kind of automatic centering centering device and pre-tightening method when crankshaft and frame total assembly, including frame, carrier plate and multiple groups of screwing component, the carrier plate is also equipped with multiple ultrasonic detection pieces, for detecting gap profile data in bearing pre-tightening process;Screwing component is tightened to bolt in stages, the gap profile data between current crankshaft main journal and bearing bush is detected by ultrasonic detection piece, it is continued to alternately carry out bolt screwing and gap detection action when meeting setting, when not meeting setting, i.e. corresponding screwing component of the bearing bolt is carried out corresponding action to make that gap profile is restored to be symmetric within tolerance range, continue to alternately carry out bolt screwing and gap detection action again, until gap profile data reaches setting range, automatically carry out centering centering action, greatly shorten the centering time when crankshaft and frame total assembly.

Description

Technical Field

[0001] This invention relates to the field of diesel engine assembly technology, specifically to an automatic self-aligning device and pre-tightening method for the assembly of crankshaft and frame. Background Technology

[0002] In marine diesel engines, the crankshaft is installed inside the frame by multiple bearings. Each bearing corresponds one-to-one with the main journal of the crankshaft. During assembly, it is necessary to ensure good coaxiality between the main journal and the inner hole of the bearing to avoid abnormal wear, vibration, or even bearing burnout during operation.

[0003] Currently, in the conventional process of crankshaft and frame assembly, the crankshaft is usually first hoisted to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half (lower bearing shell) of each bearing. Then, the upper half (upper bearing shell and bearing cap) of the bearing is closed, and a pre-tightening connection is made using several bolts. During the pre-tightening process, the tightening force of the bolts is directly transmitted to the bearing housing and bearing shell, causing deformation of the bearing structure, which in turn changes the coaxiality between the bearing inner bore and the crankshaft main journal. To address the above-mentioned coaxiality deviation problem, the commonly used self-aligning method is to gradually tighten the bolts in multiple stages during the pre-tightening process, with each pre-tightening operation completed. Then, the crankshaft is rotated, and dial indicators are set up at each main journal position. The coaxiality is judged by measuring the runout or radial offset of the main journal relative to the bearing hole. If the deviation exceeds the standard at a certain point, the bolts of the corresponding bearing are locally adjusted according to the test results (such as increasing or decreasing the tightening force). Then the test and adjustment are repeated until the coaxiality of all main journals meets the assembly requirements. The entire adjustment process relies on manual operation of dial indicators for point-by-point testing and requires multiple crankshaft rotations. The operation is cumbersome and time-consuming, resulting in a long self-alignment time when assembling the crankshaft and the frame, which seriously restricts the overall assembly efficiency of the marine diesel engine.

[0004] Therefore, this invention proposes an automatic self-aligning device and pre-tightening method for crankshaft and frame assembly to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide an automatic self-aligning device and pre-tightening method for crankshaft and frame assembly, in order to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following technical solution: An automatic self-aligning and pre-tightening method for crankshaft and frame assembly includes the following steps: S1: Hoist the crankshaft to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half of the corresponding bearing; S2: Close the upper part of the bearing and pre-tighten it with bolts. During the pre-tightening process, tighten the bolts in stages. After each stage of tightening is completed, stop for a certain period of time. During the stop, detect and acquire the gap profile data between each main journal of the crankshaft and its corresponding bearing. The gap profile data is used to feed back the alignment status between the crankshaft main journal and the bearing. If the gap profile data between all main journals and their corresponding bearings meets the set requirements, continue to the next stage of tightening. If there are any discrepancies, tighten the bolts on the corresponding bearings until the gap profile enters the set tolerance range. After adjustment, continue to the next stage of tightening until the gap profile data between all main journals and their corresponding bearings reaches the set final target range, thus completing the crankshaft and bearing self-alignment.

[0007] An automatic self-aligning device for crankshaft and frame assembly is provided to realize the above-mentioned automatic self-aligning and pre-tightening method for crankshaft and frame assembly. The device includes a frame, a carrier plate on the frame, and multiple sets of tightening assemblies on the carrier plate for tightening bearing bolts. The tightening assembly includes, from top to bottom, a drive component for providing tightening torque, a torque sensor for monitoring the output torque during tightening, a tightening shaft, and a sleeve adapted to the bearing bolt. The tightening assembly also includes an axial feed component for driving the tightening shaft to move axially. The carrier plate is also provided with multiple ultrasonic detectors for detecting the gap profile data between the crankshaft main journal and the bearing bush.

[0008] In one alternative: the automatic self-aligning device further includes a drive assembly for driving the carrier plate to rise and fall, thereby driving multiple twisting assemblies to move down synchronously and connect with the corresponding bearing bolts.

[0009] In one alternative embodiment: the carrier plate is provided with mounting rods corresponding one-to-one with the ultrasonic detectors, the mounting rods comprising rigid rod segments and plastic rod segments, and the ultrasonic detectors are located at the end of the plastic rod segment away from the rigid rod segment.

[0010] In one alternative embodiment: the automatic self-aligning device further includes an adjustment component for adjusting the position of the screwing components. The adjustment component includes two parallel first mounting slots, each of which is slidably provided with half the number of screwing components. A frame is provided on the first slide, and a second slide is slidably mounted on the frame. The sliding path of the second slide is perpendicular to the sliding path of the first slide. Multiple sets of screwing components are respectively provided on the second slide. The first slide and the second slide are also provided with a first positioning component.

[0011] In one alternative: the tightening assembly is detachably mounted on the corresponding second slide, so that the number of tightening assemblies can be increased or decreased according to the bearing bolt to be tightened.

[0012] In one alternative: the carrier plate is further provided with a second mounting groove, the second mounting groove is provided with a third slide corresponding to the ultrasonic detector, a plurality of ultrasonic detectors are provided on the corresponding third slide, and the third slide is further provided with a second positioning component.

[0013] In one alternative: the first positioning component includes a telescopic member and an abutment block disposed at the movable end of the telescopic member, and the second positioning component has the same structure as the first positioning component.

[0014] The method for automatic self-aligning and pre-tightening using the automatic self-aligning and alignment device for crankshaft and frame assembly described in any of the above technical solutions includes the following steps: S1: Hoist the crankshaft to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half of the corresponding bearing; S2: Close the upper part of the bearing, and pre-tighten the bearing by matching the screwing assembly with the bolts one by one. Use the ultrasonic detector to detect the gap profile data between the crankshaft main journal and the corresponding bearing shell one by one. During the pre-tightening process, the screwing assembly tightens the bolts in stages. After each stage of tightening is completed, stop for a certain period of time. During the stop, the ultrasonic detector detects and acquires the gap profile data between each crankshaft main journal and the corresponding bearing shell. The gap profile data is used to feed back the alignment status between the crankshaft main journal and the bearing. If the gap profile data between all main journals and the corresponding bearing shells meets the set, the next stage of tightening continues. If there is any discrepancy, the corresponding screwing assembly tightens and adjusts the bolts on the corresponding bearing until the gap profile enters the set tolerance range. After adjustment, the next stage of tightening continues until the gap profile data between all main journals and the corresponding bearing shells reaches the set final target range, thus completing the crankshaft and bearing alignment.

[0015] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: The tightening assembly performs pre-tightening actions in stages according to the settings. After each stage of tightening is completed, it stops for a certain period of time. During the stop tightening period, the ultrasonic detector detects the gap profile data between the crankshaft main journal and the bearing bush. If it meets the settings, the bolt tightening and gap detection actions continue to alternate. If it does not meet the settings, the tightening assembly corresponding to the bearing bolt performs the corresponding action to restore the gap profile to a symmetrical shape within the tolerance range. Then the bolt tightening and gap detection actions continue to alternate until the gap profile data reaches the set range. The operation is simple and convenient, and the self-aligning and centering actions are performed automatically, which greatly shortens the self-aligning time during the assembly of the crankshaft and the frame, thereby improving the overall assembly efficiency of the marine diesel engine.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Furthermore, these drawings and textual descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments.

[0018] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0019] Figure 2 This is a cross-sectional view of the crankshaft main journal and bearing under static conditions.

[0020] Figure 3 This is a schematic diagram of the arrangement of the ultrasonic detector on the crankshaft in an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of the carrier plate in an embodiment of the present invention.

[0022] Figure 5 for Figure 1 Enlarged view of point A in the middle.

[0023] Figure reference numerals: 1-Frame, 2-Carrier plate, 3-Drive assembly, 4-Turning assembly, 5-Mounting rod, 501-Rigid rod segment, 502-Plastic rod segment, 6-Ultrasonic detector, 7-Adjustment assembly, 701-First mounting slot, 702-First slide, 703-Frame, 704-Second slide, 705-Positioning component, 8-Second mounting slot, 9-Third slide. Detailed Implementation

[0024] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0025] An automatic self-aligning and pre-tightening method for crankshaft and frame assembly includes the following steps: S1: Hoist the crankshaft to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half of the corresponding bearing; S2: Close the upper part of the bearing and pre-tighten it with bolts. During the pre-tightening process, tighten the bolts in stages. After each stage of tightening is completed, stop for a certain period of time. During the stop, detect and acquire the gap profile data between each main journal of the crankshaft and its corresponding bearing. The gap profile data is used to feed back the alignment status between the crankshaft main journal and the bearing. When the gap profile data between all main journals and their corresponding bearings meets the set, continue to the next stage of tightening. If there is any that does not meet the set, tighten the bolts on the corresponding bearing until the gap profile enters the set tolerance range. After adjustment, continue to the next stage of tightening until the gap profile data between all main journals and their corresponding bearings reaches the set final target range, thereby completing the crankshaft and bearing self-alignment.

[0026] It should be noted that during the assembly of the crankshaft and frame of a marine diesel engine, each main journal of the crankshaft is supported in a corresponding bearing (including the lower and upper bearing shells). A radial clearance is designed between the main journal and the bearing shell to ensure the formation of a lubricating oil film. In a static, non-operating state, the crankshaft is subjected to its own gravity, causing the main journals to sink and shift relative to the bearing center along the direction of gravity. This results in a non-uniform distribution of the annular clearance between the main journal and the bearing shell circumferentially; that is, the clearance is smaller on one side (lower part) in the direction of gravity, and larger on the opposite side (upper part), forming an eccentric annular clearance. The contour characteristics of this eccentric annular clearance are directly related to the relative positional relationship between the crankshaft main journal centerline and the bearing centerline. Specifically: under static conditions, due to gravity, the clearance contour exhibits a symmetrical eccentric distribution within a certain range (e.g., ...). Figure 2 As shown in the figure, this state represents the center line of the main journal and the center line of the bearing when the crankshaft is rotating. If there is a coaxiality deviation between the crankshaft and the bearing, the clearance profile will show that the circumferential clearance thickness is asymmetrical and abnormally large in a specific direction. Therefore, by accurately measuring the circumferential profile of the clearance between the main journal and the bearing bush under static conditions, the eccentricity and eccentricity direction of the crankshaft main journal relative to the bearing can be deduced. Thus, the clearance profile detection can be used as a direct criterion for the self-alignment state. If the clearance profile shows asymmetrical distortion, it indicates that there is an uncorrected coaxiality error, which needs to be corrected by adjusting the bearing bolt preload to drive changes in the bearing structure.

[0027] Please see Figures 1-3An automatic self-aligning device for crankshaft and frame assembly is disclosed, which is used to realize the above-mentioned automatic self-aligning and pre-tightening method for crankshaft and frame assembly. The device includes a frame 1, a carrier plate 2 on the frame 1, and multiple sets of tightening components 4 on the carrier plate 2 for tightening bearing bolts. The tightening components 4, from top to bottom, include a drive component for providing tightening torque, a torque sensor for monitoring the output torque during tightening, a tightening shaft, and a sleeve adapted to the bearing bolt. The tightening components 4 also include an axial feed component for driving the tightening shaft to move axially (the tightening components 4 are similar to the tightening machine in the prior art, and the specific composition, connection relationship and working principle of each component are not described in detail here). The carrier plate 2 is also provided with multiple ultrasonic detectors 6 for detecting the gap contour data between the crankshaft main journal and the bearing bush.

[0028] The corresponding bolt is pre-tightened by tightening the screws using the tightening component 4. During the pre-tightening process, the tightening component 4 performs pre-tightening actions in stages according to a set procedure. After each stage of tightening action is completed (i.e., the bolt is tightened to a certain stroke), it stops for a certain period of time. During the stop tightening period, the ultrasonic detector 6 detects the gap profile data between the crankshaft main journal and the bearing bush (the ultrasonic detector 6 is located on the side of the crankshaft connecting rod journal and faces the corresponding main journal, such as...). Figure 3 As shown), if the setting is met (i.e., the gap profile is symmetrical within the tolerance range), the bolt tightening and gap detection actions continue to alternate. If the setting is not met (i.e., the gap profile is skewed beyond the tolerance range), the tightening component 4 corresponding to the bearing bolt will perform a corresponding action (e.g., if the bolt on the left side of the bearing is too tight, causing the gap profile on that side to be too small (exceeding the normal performance of this stage), the tightening component 4 corresponding to that bolt will be tightened in the opposite direction for a certain stroke, so that the target bolt is loosened to a certain extent, or it can be adjusted in coordination with the bolt on the other side. The corresponding linkage control algorithm is existing technology and will not be described in detail here) so that the gap profile is restored to a symmetrical shape within the tolerance range, and the bolt tightening and gap detection actions continue to alternate until the gap profile data reaches the set range (i.e., the gap is reduced to the target position and is symmetrical, while the bolt tightening force is also within the process requirements to ensure the stability of the bearing connection). The operation is simple and convenient, and the self-aligning and centering actions are performed automatically, which greatly shortens the self-aligning time during the assembly of the crankshaft and the frame, thereby improving the overall assembly efficiency of the marine diesel engine.

[0029] Furthermore, the automatic self-aligning device also includes a drive assembly 3 for driving the carrier plate 2 to rise and fall. The rise and fall of the carrier plate 2 drives multiple tightening assemblies 4 to move down synchronously and connect with the corresponding bearing bolts. After the tightening assembly 4 connects with the corresponding bolts, the subsequent axial feed tightening action is driven by the axial feed component in the tightening assembly 4.

[0030] Furthermore, the carrier plate 2 is provided with mounting rods 5 corresponding to the ultrasonic detectors 6 one by one. The mounting rods 5 include rigid rod segments 501 and plastic rod segments 502. The ultrasonic detectors 6 are located at the end of the plastic rod segments 502 away from the rigid rod segments 501. The plastic rod segments 502 are made of polymer materials and can bend, twist, and change shape under external force. When the external force is removed, the rod segment can maintain its deformed shape (common in microphone support rods in the prior art), thereby maintaining support for the ultrasonic detectors 6. Through the design of the plastic rod segments 502, the ultrasonic detectors 6 can be positioned at the target location by bypassing the connecting rod journal.

[0031] Please see Figure 1 , Figure 4 and Figure 5 In one embodiment of the present invention, the automatic centering device further includes an adjustment component 7 for adjusting the position of the turning component 4. The adjustment component 7 includes two parallel first mounting grooves 701. Half the number of first slide blocks 702 of the turning component 4 are slidably arranged in each of the two first mounting grooves 701. A frame 703 is provided on the first slide block 702. A second slide block 704 is slidably engaged on the frame 703. The sliding path of the second slide block 704 is perpendicular to the sliding path of the first slide block 702. Multiple sets of turning components 4 are respectively arranged on the second slide block 704. A first positioning component 705 is also provided on the first slide block 702 and the second slide block 704. The first positioning component 705 realizes the positioning of the first slide block 702 and the second slide block 704 after adjustment. The tightening component 4 is detachably mounted on the corresponding second slide 704 (such as by means of several bolts, pins, etc.) so that the number of tightening components 4 can be increased or decreased according to the bearing bolts to be tightened (the number of crankshaft bearings varies on different types of diesel engines). The carrier plate 2 is also provided with a second mounting groove 8, and the second mounting groove 8 is provided with a third slide 9 corresponding to the ultrasonic detector 6. Multiple ultrasonic detectors 6 are located on their corresponding third slides 9. The third slide 9 is also provided with a second positioning component. In addition, a single ultrasonic detector 6 can be independently controlled to open and close, so as to adapt to the detection requirements of different types of diesel engines (different types of diesel engines have different numbers of crankshaft bearings).

[0032] In this embodiment, the bolts on the crankshaft bearing are usually arranged in two symmetrical positions. Therefore, two rows of tightening components 4 are set to correspond to the bolts on both sides of the bearing. The positions and quantities of the tightening components 4 and ultrasonic detectors 6 are set according to the actual position and quantity of the diesel engine bearing in the final assembly.

[0033] Furthermore, in this embodiment, the first positioning component 705 includes a telescopic member (preferably an electric telescopic rod) and an abutment block disposed at the movable end of the telescopic member. The second positioning component has the same structure as the first positioning component. The telescopic member extends and drives the abutment block to abut against the groove wall of the first mounting groove 701 / the inner wall of the frame 703 / the groove wall of the second mounting groove 8 to achieve the positioning of the corresponding component.

[0034] The method for automatic self-aligning and pre-tightening using the automatic self-aligning and alignment device for crankshaft and frame assembly described in any of the above technical solutions includes the following steps: S1: Hoist the crankshaft to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half of the corresponding bearing; S2: Close the upper part of the bearing, and pre-tighten the bearing by matching the bolts with the screwing assembly 4 one by one. Use the ultrasonic detector 6 to detect the gap profile data between the crankshaft main journal and the corresponding bearing shell one by one. During the pre-tightening process, the screwing assembly 4 tightens the bolts in stages. After each stage of tightening is completed, stop for a certain period of time. During the stop, the ultrasonic detector 6 detects and acquires the gap profile data between each crankshaft main journal and the corresponding bearing shell. The gap profile data is used to feed back the alignment status between the crankshaft main journal and the bearing. When the gap profile data between all main journals and the corresponding bearing shells meets the set, the next stage of tightening continues. If there is any discrepancy, the screwing assembly 4 adjusts the bolts on the corresponding bearing until the gap profile enters the set tolerance range. After adjustment, the next stage of tightening continues until the gap profile data between all main journals and the corresponding bearing shells reaches the set final target range, thus completing the crankshaft and bearing alignment.

[0035] 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. An automatic self-aligning and pre-tightening method for crankshaft and frame assembly, characterized in that, Includes the following steps: S1: Hoist the crankshaft to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half of the corresponding bearing; S2: Close the upper part of the bearing and pre-tighten it with bolts. During the pre-tightening process, tighten the bolts in stages. After each stage of tightening is completed, stop for a certain period of time. During the stop, detect and acquire the gap profile data between each main journal of the crankshaft and its corresponding bearing. The gap profile data is used to feed back the alignment status between the crankshaft main journal and the bearing. If the gap profile data between all main journals and their corresponding bearings meets the set requirements, continue to the next stage of tightening. If there are any discrepancies, tighten the bolts on the corresponding bearings until the gap profile enters the set tolerance range. After adjustment, continue to the next stage of tightening until the gap profile data between all main journals and their corresponding bearings reaches the set final target range, thus completing the crankshaft and bearing self-alignment.

2. An automatic self-aligning and centering device for crankshaft and frame assembly, used to implement the automatic self-aligning and pre-tightening method for crankshaft and frame assembly as described in claim 1, characterized in that, It includes a frame (1), a carrier plate (2) on the frame (1) and multiple sets of tightening components (4) on the carrier plate (2) for tightening bearing bolts. The carrier plate (2) is also provided with multiple ultrasonic detectors (6) for detecting the gap profile data between the crankshaft main journal and the bearing bush.

3. The automatic self-aligning device for crankshaft and frame assembly according to claim 2, characterized in that, The automatic self-aligning device also includes a drive assembly (3) for driving the carrier plate (2) to rise and fall. The rise and fall of the carrier plate (2) drives multiple twisting assemblies (4) to move down synchronously and connect with the corresponding bearing bolts.

4. The automatic self-aligning device for crankshaft and frame assembly according to claim 2, characterized in that, The carrier plate (2) is provided with mounting rods (5) that correspond one-to-one with the ultrasonic probe (6). The mounting rod (5) includes a rigid rod section (501) and a plastic rod section (502). The ultrasonic probe (6) is located at the end of the plastic rod section (502) away from the rigid rod section (501).

5. The automatic self-aligning device for crankshaft and frame assembly according to claim 2, characterized in that, The automatic centering device further includes an adjustment component (7) for adjusting the position of the screwing component (4). The adjustment component (7) includes two parallel first mounting slots (701). Each of the two first mounting slots (701) is slidably provided with a first slide block (702) equal to half the number of screwing components (4). A frame (703) is provided on the first slide block (702). A second slide block (704) is slidably mounted on the frame (703). The sliding path of the second slide block (704) is perpendicular to the sliding path of the first slide block (702). Multiple sets of screwing components (4) are respectively provided on the second slide block (704). A first positioning component (705) is also provided on the first slide block (702) and the second slide block (704).

6. The automatic self-aligning device for crankshaft and frame assembly according to claim 5, characterized in that, The screwing assembly (4) is detachably mounted on the corresponding second slide (704) so ​​that the number of screwing assemblies (4) can be increased or decreased according to the bearing bolt to be screwed.

7. The automatic self-aligning device for crankshaft and frame assembly according to claim 5, characterized in that, The carrier plate (2) is also provided with a second mounting groove (8), and the second mounting groove (8) is provided with a third slide (9) corresponding to the ultrasonic detector (6) one by one. Multiple ultrasonic detectors (6) are provided on the corresponding third slide (9), and the third slide (9) is also provided with a second positioning component.

8. The automatic self-aligning device for crankshaft and frame assembly according to claim 7, characterized in that, The first positioning component (705) includes a telescopic member and an abutment block disposed at the movable end of the telescopic member. The second positioning component has the same structure as the first positioning component.

9. The automatic self-aligning device for crankshaft and frame assembly according to any one of claims 2-8, characterized in that, The automatic self-aligning and pre-tightening method includes the following steps: S1: Hoist the crankshaft to the corresponding position on the frame, so that each main journal of the crankshaft sits on the lower half of the corresponding bearing; S2: Close the upper part of the bearing, and pre-tighten the bearing by matching the bolts with the screwing assembly (4). Use the ultrasonic detector (6) to detect the gap profile data between the main journal and the corresponding bearing shell. During the pre-tightening process, the screwing assembly (4) tightens the bolts in stages. After each stage of tightening is completed, stop for a certain period of time. During the stop, the ultrasonic detector (6) detects and obtains the gap profile data between each main journal of the crankshaft and the corresponding bearing shell. The gap profile data is used to feed back the alignment status between the main journal of the crankshaft and the bearing. When the gap profile data between all main journals and the corresponding bearing shells meets the set, the next stage of tightening is continued. If there is a discrepancy, the corresponding screwing assembly (4) will screw and adjust the bolts on the corresponding bearing until the gap profile enters the set tolerance range. After adjustment, the next stage of tightening is continued until the gap profile data between all main journals and the corresponding bearing shells reaches the set final target range, thereby completing the crankshaft and bearing alignment work.

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