A multi-piece engine cylinder liner bore ion nitriding protection tooling

Abstract

A multi-piece engine cylinder liner hole ion nitriding protection tool, including a support disc, three support columns are uniformly distributed and inserted on the bottom surface of the support disc; two circles of stepped holes are uniformly distributed on the upper surface of the support disc, a bottom seat is respectively inserted in each stepped hole, an annular groove and a positioning clamping edge are arranged on the upper end of the bottom seat, and a lower shielding sleeve is inserted in the annular groove; a transition shaft sleeve is inserted on the upper end of the lower shielding sleeve, an annular groove and a positioning clamping edge are arranged on the upper end of the transition shaft sleeve, and an upper shielding sleeve is inserted in the annular groove; an upper end cover is buckled on the upper end of the upper shielding sleeve, a top cover plate is supported on the support disc through a support rod, the top cover plate is located above the upper end cover, and two circles of through holes are uniformly distributed on the top cover plate and correspond to the stepped holes one by one. The tool can not only shield the outer surface and end face of the cylinder liner, but also can place and process multiple cylinder liners at a time, realize the free circulation of nitrogen ion atmosphere in the cylinder liner hole, the nitriding layer wall thickness after processing is uniform, and the processing efficiency is high.

Description

Technical Field

[0001] This utility model relates to a tooling, specifically a tooling for ion nitriding protection of the inner hole of a thin-walled sleeve-type part. Background Technology

[0002] Due to the working environment and performance requirements, diesel engine cylinder liners need to undergo ion nitriding of their inner bores to address core issues such as wear, corrosion, and fatigue failure.

[0003] Ion nitriding is a process in which ammonia gas is introduced into a furnace in a vacuum environment, with the furnace body as the anode and the workpiece as the cathode. When electricity is applied, the ammonia gas is ionized into nitrogen ions and hydrogen ions. The nitrogen ions and hydrogen ions bombard the workpiece at high speed to heat it. The ion bombardment of the workpiece surface produces atomic sputtering. Through adsorption and diffusion, nitrogen ions penetrate into the surface of the workpiece to form a nitrided layer, thus achieving surface hardening. Ion nitriding technology has the advantages of fast nitriding speed and good nitrided layer quality.

[0004] CN222684725U discloses a tooling for ion nitriding treatment of the inner hole of sleeve-type parts, including a seat sleeve. The seat sleeve has a cavity extending through its upper and lower end faces. The seat sleeve has several vent holes spaced apart, and the upper edge of the seat sleeve is adapted to the lower end face of the sleeve-type part blank. This tooling has the following problems: First, it does not shield the non-nitrided surfaces such as the outer surface and end face of the sleeve, making it easy for a nitrided layer to form on these surfaces during use. Second, only one sleeve can be placed on each tooling. When multiple parts are processed simultaneously, the placement of the sleeves in the furnace affects their heat dissipation conditions. For example, sleeves placed on the outer ring of the cathode plate are closer to the furnace wall, resulting in faster heat dissipation and lower temperatures; sleeves placed on the inner ring are surrounded by parts at the same temperature, resulting in slower heat dissipation and higher temperatures. Furthermore, if the spacing between the sleeves is too small, it will hinder the flow of atmosphere, leading to excessively high temperatures in localized areas and affecting the processing quality. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a multi-part engine cylinder liner inner bore ion nitriding protection tooling to solve the problems mentioned in the background art.

[0006] The technical solution of this utility model is as follows: A multi-piece engine cylinder liner inner bore ion nitriding protection fixture includes a support plate. Three support columns are evenly distributed around the bottom circumference of the support plate to support the fixture. Two rings of stepped holes are evenly distributed around the support plate. A bottom seat is inserted into each stepped hole. An annular groove and a positioning clip are provided at the upper end of the bottom seat. A lower shielding sleeve is inserted into the annular groove. The length of the lower shielding sleeve is the same as that of the cylinder liner to be processed. It is used to shield the outer edge of the lower cylinder liner inserted into the positioning clip. A transition sleeve is inserted into the upper end of the lower shield sleeve. An annular groove and a positioning clip are also provided on the upper end of the transition sleeve. An upper shield sleeve is inserted into the annular groove. The upper shield sleeve is the same length as the cylinder liner to be processed and is used to shield the outer edge of the upper cylinder liner inserted into the positioning clip. An upper end cap is fastened to the upper end of the upper shielding sleeve. The upper end cap is annular and its central hole is consistent with the inner hole of the cylinder liner. It is used to shield the upper end face of the upper cylinder liner. A top cover plate is supported on the support plate by support rods evenly distributed around the circumference. The top cover plate is located above the upper end cover. Two rings of through holes are evenly distributed on the top cover plate, and they correspond one-to-one with two rings of stepped holes, so that the nitrogen ion atmosphere can flow freely up and down in the cylinder liner inner hole.

[0007] A further improvement of this utility model is that multiple radial holes are evenly distributed along the circumferential direction on the outer wall of the bottom seat sleeve to improve the flow effect of nitrogen ion atmosphere in the cylinder liner.

[0008] A further improvement of this utility model is that multiple radial holes are evenly distributed along the circumferential direction on the outer wall of the transition bushing to improve the flow effect of nitrogen ion atmosphere in the cylinder liner.

[0009] A further improvement of this utility model is that: the lower end of the support rod passes through the support plate and is fixed to the support plate by a nut; the upper end of the support rod is inserted into the connecting hole on the top cover plate by clearance fit; and a retaining ring and a support sleeve are respectively provided on the upper end of the support rod above and below the top cover plate to adjust the gap between the top cover plate and the upper end cover.

[0010] A further improvement of this utility model is that the distance between the top cover plate and the upper end cover is 100-200mm.

[0011] A further improvement of this utility model is that a positioning hole is provided on the support plate to position the thermocouple on the cathode plate of the nitriding furnace during installation, ensuring that the furnace is always in the same position.

[0012] A further improvement of this utility model is that the number of stepped holes on the support plate is 25, with 16 on the outer ring and 9 on the inner ring.

[0013] The technological advancements achieved by this utility model due to the adoption of the above technical solution are as follows: By evenly distributing two rings of stepped holes along the circumference on the support plate, and inserting a bottom seat sleeve into each stepped hole, and then sequentially installing a lower shielding sleeve, a transition bushing, and an upper end cap on the bottom seat sleeve, it is possible not only to shield the non-nitrided surfaces such as the outer surface and end face of the cylinder liner, thus preventing the formation of a nitrided layer on the outer surface and end face of the cylinder liner, but also to allow multiple cylinder liners to be processed at once. This avoids the abnormal concentration of electric field intensity or uneven ion density caused by uneven placement when processing multiple cylinder liners simultaneously, which could lead to strong arc discharge and cause the inner surface of the cylinder liner to be ablated or to form a nitrided layer with uneven wall thickness. It also enables the free flow of nitrogen ion atmosphere in the inner hole of the cylinder liner, resulting in a uniform wall thickness of the nitrided layer after processing, and high processing efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Figure 2 yes Figure 1 Top view.

[0016] Figure 3 yes Figure 1 Top view of the central support plate 1.

[0017] Figure 4 This is a structural diagram of the bottom seat cover.

[0018] Figure 5 This is a schematic diagram of the transition bushing.

[0019] In the figure: support plate 1, stepped hole 101, positioning hole 102, bottom seat 2, annular groove 201, positioning edge 202, radial hole 203, lower shielding sleeve 3, transition bushing 4, annular groove 401, positioning edge 402, radial hole 403, upper shielding sleeve 5, upper end cover 6, top cover plate 7, support sleeve 8, retaining ring 9, support rod 10, support column 11, cathode plate 12, cylinder liner 13. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0021] like Figures 1-5 As shown, this utility model relates to a multi-piece engine cylinder liner inner bore ion nitriding protection tooling, including a disc-shaped support plate 1. Three insertion holes are evenly distributed around the bottom circumference of the support plate 1, and three support columns 11 are tightly inserted through the three insertion holes to support the tooling and improve the nitrogen gas flow effect, so that the nitrogen ion atmosphere can flow freely up and down in the cylinder liner inner bore, solving the problem of uneven distribution of nitrogen ion atmosphere in the cylinder liner inner bore cavity, resulting in uneven nitriding layer.

[0022] Two rings of stepped holes 101 are evenly distributed along the circumference on the support plate 1. In this embodiment, 25 stepped holes are used as an example, with 16 in the outer ring and 9 in the inner ring. The upper port diameter of each stepped hole 101 is larger than the lower port diameter, and the lower port diameter is equivalent to the inner diameter of the cylinder liner to be processed. A bottom seat 2 is inserted into the upper port of each stepped hole 101 through a small clearance fit. An annular groove 201 and a positioning edge 202 are provided on the upper end of the bottom seat 2. The annular groove 201 is located outside the positioning edge 202, and a lower shielding sleeve 3 is inserted into the annular groove 201 through a clearance fit. The lower shielding sleeve 3 is tubular and has the same length as the cylinder liner to be processed. It is used to shield the outer edge of the lower cylinder liner 13 inserted into the positioning edge 202.

[0023] A transition sleeve 4 is inserted into the upper end of the lower shielding sleeve 3. The lower end of the transition sleeve 4 is provided with a retaining edge and is fitted onto the upper outer edge of the lower shielding sleeve 3 through a clearance fit. The inner hole of the transition sleeve 4 is equivalent to the inner diameter of the cylinder liner 13 to be processed. The upper end of the transition sleeve 4 is also provided with a positioning retaining edge 402 arranged inside and outside and an annular groove 401. An upper shielding sleeve 5 is inserted into the annular groove 401 through a clearance fit. The upper shielding sleeve 5 is the same length as the cylinder liner 13 to be processed and is used to shield the outer edge of the upper cylinder liner 13 into which the positioning retaining edge is inserted.

[0024] Upper end caps 6 are fastened to the upper end of the upper shielding sleeve 5. The upper end cap 6 is annular and its central hole is consistent with the inner hole of the cylinder liner 13. The lower outer edge of the upper end cap 6 is provided with a retaining edge and is fitted onto the upper end of the upper shielding sleeve 5 through a gap fit, so that the upper shielding sleeve 5 and the installed upper cylinder liner 13 both rest on the stepped surface inside the upper end cap 6, which is used to shield the upper end surface of the upper cylinder liner 13.

[0025] A top cover plate 7 is supported on the support plate 1 by three circumferentially distributed support rods 10. The top cover plate 7 is located above the upper end cover 6, and the distance between the top cover plate 7 and the upper end cover 6 is 100-200mm. Two rings of through holes 701 are evenly distributed on the top cover plate 7, which correspond one-to-one with two rings of stepped holes 101, so that the nitrogen ion atmosphere can flow freely up and down in the inner hole of the cylinder liner 13.

[0026] The lower end of the support rod 10 passes through the support plate 1 and is fixed to the support plate 1 by a nut; the upper end of the support rod 10 is inserted into the connecting hole on the top cover plate 7 through clearance fit; a retaining ring 9 and a support sleeve 8 are respectively provided on the upper end of the support rod 10 above and below the top cover plate 7, so as to adjust the gap between the top cover plate 7 and the upper cover 6.

[0027] Multiple radial holes 203 are evenly distributed along the circumference on the outer wall of the bottom sleeve 2 to improve the flow of nitrogen ion atmosphere within the cylinder liner. Similarly, multiple radial holes 403 are evenly distributed along the circumference on the outer wall of the transition sleeve 4 to further improve the flow of nitrogen ion atmosphere within the cylinder liner.

[0028] A positioning hole 102 is provided on the support plate 1 to position the thermocouple on the cathode plate 12 of the nitriding furnace during installation, so as to ensure that the position is consistent each time the furnace is loaded.

[0029] During the ion nitriding process, the furnace wall of the nitriding furnace serves as the anode, and the cathode plate 12 serves as the cathode. The tooling and the two-layer cylinder liner 13 mounted on it are supported on the cathode plate 12 of the nitriding furnace by the support column 11, so the tooling and cylinder liner simultaneously serve as cathodes.

[0030] During processing, the nitriding furnace is first evacuated to a vacuum state, and then a nitrogen-containing atmosphere is introduced. Then, electricity is applied, and due to the glow discharge phenomenon, a soft, neon-like light is generated covering the surface of the workpiece. At this time, the ionized gas components (N+, H+) are accelerated by the electric field and impact the surface of the workpiece, achieving heating of the cylinder liner on one hand, and allowing nitrogen ions to penetrate into the inner surface of the cylinder liner 13 to form a nitrided layer on the other. The bottom seat 2, lower shielding sleeve 3, transition bushing 4, upper shielding sleeve 5, and upper end cover 6 shield the outer surface and end face of the two-layer cylinder liner 13, preventing the formation of a nitrided layer on these surfaces. Simultaneously, the stepped hole 101 on the support plate 1, the central holes of the bottom seat 2, transition bushing 4, and upper end cover 6, and the through holes on the top cover plate 7 allow the nitrogen ion atmosphere to flow freely up and down within the inner hole of the cylinder liner 13, resulting in a uniform wall thickness of the nitrided layer after processing.

[0031] The embodiments described above are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Various modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. A multi-part engine cylinder liner inner bore ion nitriding protection tooling, characterized in that: Includes a support plate, with three support columns evenly distributed around the bottom circumference of the support plate to support the tooling; Two rings of stepped holes are evenly distributed along the circumference on the support plate. A bottom seat is inserted into each stepped hole. An annular groove and a positioning clip are provided at the upper end of the bottom seat. A lower shielding sleeve is inserted into the annular groove. The length of the lower shielding sleeve is the same as that of the cylinder liner to be processed. It is used to shield the outer edge of the lower cylinder liner that is inserted into the positioning clip. A transition sleeve is inserted into the upper end of the lower shield sleeve. An annular groove and a positioning clip are also provided on the upper end of the transition sleeve. An upper shield sleeve is inserted into the annular groove. The upper shield sleeve is the same length as the cylinder liner to be processed and is used to shield the outer edge of the upper cylinder liner inserted into the positioning clip. An upper end cap is fastened to the upper end of the upper shielding sleeve. The upper end cap is annular and its central hole is consistent with the inner hole of the cylinder liner. It is used to shield the upper end face of the upper cylinder liner. A top cover plate is supported on the support plate by support rods evenly distributed around the circumference. The top cover plate is located above the upper end cover. Two rings of through holes are evenly distributed on the top cover plate, and they correspond one-to-one with two rings of stepped holes, so that the nitrogen ion atmosphere can flow freely up and down in the cylinder liner inner hole.

2. The multi-part engine cylinder liner inner bore ion nitriding protection tooling according to claim 1, characterized in that: Multiple radial holes are evenly distributed along the circumference on the outer wall of the bottom seat to improve the flow of nitrogen ion atmosphere within the cylinder liner.

3. A multi-part engine cylinder liner inner bore ion nitriding protection tooling according to claim 1 or 2, characterized in that: Multiple radial holes are evenly distributed along the circumference on the outer wall of the transition bushing to improve the flow of nitrogen ion atmosphere within the cylinder liner.

4. The multi-part engine cylinder liner inner bore ion nitriding protection tooling according to claim 1, characterized in that: The lower end of the support rod passes through the support plate and is fixed to the support plate by a nut; the upper end of the support rod is inserted into the connecting hole on the top cover plate by clearance fit. A retaining ring and a support sleeve are respectively provided on the upper end of the support rod above and below the top cover plate to adjust the gap between the top cover plate and the upper end cover.

5. The multi-part engine cylinder liner inner bore ion nitriding protection tooling according to claim 4, characterized in that: The distance between the top cover plate and the upper end cover is 100-200mm.

6. The multi-part engine cylinder liner inner bore ion nitriding protection tooling according to claim 1, characterized in that: A positioning hole is provided on the support plate to position the thermocouple on the cathode plate of the nitriding furnace during installation, ensuring that the position is consistent each time the furnace is loaded.

7. A multi-part engine cylinder liner inner bore ion nitriding protection tooling according to claim 1 or 6, characterized in that: The support plate has 25 stepped holes, with 16 on the outer ring and 9 on the inner ring.

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