A polishing shoe for partial quenching of crankshaft journal

Abstract

This invention discloses a polishing tile for localized quenching of crankshaft journals. It includes a polishing tile body with multiple toothed grooves formed on both sides of the body along the inner ring. This invention ensures that the polishing deformation in the non-quenched areas on both sides of the journal is less than or equal to that in the intermediate quenched area, and that the journal protrusion remains unchanged before and after polishing within the cylindricity evaluation width range, thus guaranteeing both the barrel surface finish and the cylindricity of the journal.

Description

Technical Field

[0001] This invention belongs to the technical field of crankshaft polishing tiles, specifically relating to a polishing tile used for local quenching of crankshaft journals. Background Technology

[0002] The main journal and connecting rod journal of a certain crankshaft (hereinafter referred to as journals) require local quenching, such as Figure 1 As shown, 1 is the induction hardening zone, 2 is the non-hardening zone on both sides of the journal, and 3 is the groove on both sides. This local hardening can improve the wear resistance of the journal surface and ensure that the fatigue strength of the groove on both sides of the journal is not reduced.

[0003] To improve lubrication of the journals and reduce uneven wear of the bearings, the crankshaft journals feature a central drum-shaped protrusion design. The amount of this drum shape is measured and evaluated using barrel surface coverage, with an evaluation width of 10mm. Figure 2 As shown, the surface finish of the barrel is ensured by grinding wheel shaping during the fine grinding process before journal polishing.

[0004] At the same time, the journal also has cylindricity requirements, and its evaluation width (12mm) is as follows: Figure 3 As shown.

[0005] The cylindricity evaluation width of the journal (12mm) is greater than the median value of 11.5mm defined for the induction hardening width of the journal, thus covering the high hardness zone of the journal and the ordinary hardness zone of the journal. Figure 4 As shown, under the same polishing force, the amount of material removed in the non-quenched (low hardness) zone is greater than that in the quenched (high hardness) zone.

[0006] There is a polishing band between the journal polishing pad and the journal, such as... Figure 5 As shown, the polishing process structure consists of a polishing soft tile 1, a polishing belt 2, a polishing hard tile 3, and a journal 4. 5 is a conveying device, and 6 is a sanding belt frame. Figure 6 As shown, even when the polishing roughness is within acceptable limits, it is difficult to simultaneously meet the requirements for cylindricity and barrel surface finish when the polishing time is shortened, the polishing pressure is reduced, and the equipment precision is adjusted to the optimal state.

[0007] The reason why it is difficult to simultaneously meet the requirements for barrel surface finish and cylindricity in existing journal polishing is:

[0008] To ensure cylindricity, the journal must have a central bulge, which increases cylindricity. If the bulge is insufficient, the cylindricity will be substandard. Cylindricity measurement and evaluation lengths must exceed the defined median value of the journal's quenching width. During polishing, the non-quenched areas with lower hardness require more polishing than the quenched areas with higher hardness, removing more material. This results in a larger relative height between the outer diameters on both sides of the non-quenched areas and the central bulge corresponding to the quenched areas after polishing, making it easier for the cylindricity to exceed the upper limit. Figure 5 As shown. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a polishing tile for local quenching of crankshaft journals.

[0010] The technical solution adopted in this invention is: a polishing tile for local quenching of crankshaft journals, comprising a polishing tile body, wherein multiple grooves are formed in a toothed shape on both sides of the polishing tile body along the inner ring.

[0011] In a further preferred configuration, three grooves are machined on each side of the polished tile body.

[0012] In a further preferred configuration, the groove depth is 1 mm.

[0013] In a further preferred configuration, the groove is 18.6 degrees long.

[0014] In a further preferred structure, the width between two adjacent slots is less than the cylindricity evaluation width.

[0015] In a further preferred structure, the distance between two adjacent slots is 11mm-11.2mm.

[0016] In a further preferred configuration, the thickness of the polishing tile body is 16mm-16.01mm.

[0017] In a further preferred configuration, the polishing tile is disposed on the outer ring of the journal on the side of the abrasive belt frame.

[0018] A polishing device for local quenching of crankshaft journals includes a polishing tile for local quenching of crankshaft journals. The journal is provided with a sanding belt frame on one side and a conveying device on the other side. The polishing tile is located on the outer ring of the journal on the side of the sanding belt frame.

[0019] The outer ring of the journal is also provided with a polished soft pad.

[0020] This invention is applicable to the polishing of crankshaft main journals and connecting rod journals after partial quenching, where the journal surface has a hardness difference due to the quenched and non-quenched areas, while simultaneously ensuring that the barrel surface and cylindricity are qualified. The force applied by the polishing pad to the non-quenched area of ​​the journal is reduced, the amount of polishing material removed from the non-quenched area is reduced, and the polishing deformation of the entire journal is ensured to be uniform, thereby ensuring that the barrel surface and cylindricity are qualified at the same time.

[0021] This invention ensures that the polishing deformation of the non-quenched areas on both sides of the journal is less than or equal to that of the middle quenched area, and that the journal protrusion within the cylindricity evaluation width remains unchanged before and after polishing, thereby ensuring both the barrel surface and the cylindricity of the journal. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of partial quenching of the crankshaft journal (connecting rod journal);

[0023] Figure 2 This is a schematic diagram for evaluating the width of the crankshaft journal (connecting rod journal) barrel surface.

[0024] Figure 3 This is a schematic diagram illustrating the cylindricity evaluation width of crankshaft journals (connecting rod journals);

[0025] Figure 4 This is a schematic diagram showing the relationship between the quenching zone of the crankshaft journal (connecting rod journal) and the cylindricity evaluation width;

[0026] Figure 5 This is a schematic diagram of the polished tile assembly;

[0027] Figure 6 This is a schematic diagram showing the change in barrel surface finish before and after localized quenching and polishing of the journal.

[0028] Figure 7 This is a schematic diagram of the existing crankshaft journal polishing tile structure;

[0029] Figure 8 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0031] like Figure 8 As shown, the present invention includes a polished tile body a, and multiple grooves b are formed in a toothed shape on both sides of the polished tile body a along the inner circle.

[0032] In a preferred embodiment, three grooves (b) are machined on each side of the polished tile body (a).

[0033] The depth of groove b is 1mm.

[0034] The length of groove b is 18.6 degrees.

[0035] The width between two adjacent slots b is less than the cylindricity evaluation width.

[0036] The distance between two adjacent slots b is 11mm-11.2mm.

[0037] The thickness of the polished tile body is 16mm-16.01mm.

[0038] The polishing tile is located on the outer ring of journal 4 on the side of the sanding belt frame.

[0039] A sanding belt frame 6 is provided on one side of the journal 4, and a conveying device 5 is provided on the other side. The polishing tile is located on the outer ring of the journal 4 on the side of the sanding belt frame 6.

[0040] The outer ring of journal 4 is also provided with polished soft pad 1.

[0041] Example:

[0042] In the fine grinding process before polishing, the grinding wheel is used to shape the shaft to ensure that the surface finish of the journal is within a 10mm width range after fine polishing, while also ensuring that its outer diameter and roundness are qualified.

[0043] Install the original polishing tile onto the polishing machine, and then polish it by placing a 0.24mm thick polishing belt between the polishing tile and the crankshaft journal. The existing polishing tile structure, such as... Figure 7 As shown, the polishing belt thickness is 0.18mm, and the polishing diameter is φ41.49—42.008mm.

[0044] Adjust the polishing machine. While ensuring that the polishing roughness is qualified, shorten the polishing time and reduce the polishing pressure of the original polishing tile. When the equipment accuracy is adjusted to the best state, it is found that the cylindricity and barrel surface degree still cannot be qualified at the same time. It is found that the cylindricity is close to the upper limit and the barrel surface degree is close to the lower limit. The part dimensions are out of tolerance, as shown in Table 1.

[0045] Table 1: Cylindricity and Barrel Surfaceness of the Original Polished Tile After Polishing

[0046]

[0047] Polishing tile of the present invention:

[0048] On both sides of the polished tile, corresponding to the non-quenched area of ​​the journal, three grooves are symmetrically cut on each side: the groove depth is 1mm, the groove length is 18.6 degrees, and the distance between the corresponding grooves on both sides is 11 (0, +0.2). Figure 8 As shown.

[0049] The toothed grooves on both sides of the polishing tile fall within 12mm of the cylindricity evaluation width. This reduces the polishing force in the non-quenched area within the cylindricity evaluation width, thereby reducing the amount of polishing material removed in the non-quenched area.

[0050] Install the new polishing tile onto the polishing machine, and install a 0.24mm thick polishing strip between the polishing tile and the crankshaft diameter.

[0051] After the polishing tiles and polishing belts are installed on the polishing machine, the original polishing process parameters are used to start polishing production. After polishing, the journal is inspected and its roughness, barrel surface degree and coaxiality are all qualified. It can be guaranteed that the barrel surface degree dimension is controlled to the tolerance value while the cylindricity is qualified, as shown in Table 2.

[0052] Table 2: Cylindricity and Barrel Surfaceness of the Polished Tiles after Polishing (Patent)

[0053]

[0054] After the polishing tile with toothed grooves on both sides of the present invention is manufactured, it is installed on a polishing machine to process the crankshaft for testing. The cylindricity and barrel surface of the crankshaft are qualified.

[0055] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A polishing shoe for partial quenching of a crankshaft journal, characterized by: The device includes a polishing tile body, on both sides of which multiple grooves are formed in a toothed pattern along the inner ring; the width between two adjacent grooves is less than the cylindricity evaluation width; the polishing tile is located on the outer ring of the journal on the side of the abrasive belt frame; three grooves are machined on each side of the polishing tile body; the groove depth is 1mm; the groove length is 18.6 degrees; the distance between two adjacent grooves is 11mm-11.2mm; and the thickness of the polishing tile body is 16mm-16.01mm.

2. A polishing device for partial quenching of a crankshaft journal, characterized by: The invention includes a polishing tile for local quenching of crankshaft journals as described in claim 1, wherein a sanding belt frame is provided on one side of the journal and a conveying device is provided on the other side, and the polishing tile is disposed on the outer ring of the journal on the side of the sanding belt frame.

3. A polishing device for local quenching of crankshaft journals according to claim 2, characterized in that: The outer ring of the journal is also provided with a polished soft pad.

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