A tool for ion nitriding treatment of inner holes of thin-walled sleeve parts
By designing tooling for thin-walled sleeve parts, including air permeability holes in the seat sleeve and casing are connected to the thin-wall straight cylinder section, the problems of uneven distribution of nitrogen ion atmosphere and thermal deformation in the nitriding treatment of the inner holes of thin-walled sleeve parts are solved, and the hardness uniformity and the qualification rate of finished products are improved.
Patent Information
- Application Number
- CN202420766316.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-15
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-04-15
AI Technical Summary
In the prior art, the ion nitriding treatment of the inner pores of thin-walled sleeve parts has the problem of uneven distribution of nitrogen ion atmosphere, resulting in uneven hardness, and the thin-walled straight cylinder section is prone to thermal deformation during high-temperature treatment, which reduces the pass rate of the finished product.
Design a tool for ion nitriding of inner holes of thin-walled sleeves, including seat sleeves and casings. Breathable holes are provided between the seat sleeves to ensure that the nitrogen ion atmosphere can be evenly distributed; the sleeve is connected to the outside of the thin-walled straight cylinder section to transfer heat and provide a beam-shaped effect to prevent thermal deformation.
By uniformly distributing the nitrogen ion atmosphere, the hardness uniformity of the inner hole wall surface of the finished product of thin-walled sleeve parts is ensured; the sleeve effectively controls the temperature of the thin-walled straight cylinder section, avoids thermal deformation, and significantly improves the pass rate of the finished product.
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Figure CN222700392U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of heat treatment equipment for sleeve-type parts, in particular to a tool used for ion nitriding treatment of inner holes of thin-walled sleeve-type parts. Background Art
[0002] Ion nitriding is a kind of ion chemical heat treatment process that uses the glow discharge phenomenon to ionize nitrogen-containing gas to generate nitrogen ions to bombard the surface of parts, heat them and nitride them, and obtain a surface nitrided layer. It is widely used in cast iron, carbon steel, alloy steel, stainless steel and titanium alloy. After the parts are treated with ion nitriding, the hardness of the material surface can be significantly improved, making them have high wear resistance, fatigue strength, corrosion resistance and burn resistance.
[0003] At present, ion nitriding treatment of the inner hole of thin-walled sleeve parts mostly adopts ion nitriding furnace, specifically, a number of thin-walled sleeve parts blanks are placed vertically and spaced on the cathode disk in the furnace of ion nitriding furnace, and the finished thin-walled sleeve parts are removed from the cathode disk after the ion nitriding treatment. Since the thin-walled sleeve parts blanks are directly placed vertically on the cathode disk, the nitrogen ion atmosphere generated after the nitrogen-containing gas is ionized can only enter the cavity of the thin-walled sleeve parts blank from the upper port, which causes the nitrogen ion atmosphere to be mostly concentrated at the upper end of the cavity of the thin-walled sleeve parts blank, that is, the nitrogen ion atmosphere cannot be evenly distributed in the inner hole cavity of the sleeve parts blank, resulting in uneven hardness of the inner hole wall surface of the thin-walled sleeve parts after nitriding treatment due to uneven distribution of the nitrided layer. In addition, since the thickness of the thin-walled straight section of the thin-walled sleeve parts is relatively small, the thin-walled straight section will be severely thermally deformed due to the high temperature during the ion nitriding process, and the scrap rate of the thin-walled sleeve parts during correction is relatively high, especially for the thin-walled sleeve parts with a thickness of less than 3mm, the thermal deformation of the workpiece after ion nitriding is more serious, which seriously restricts the qualified rate of the finished workpieces of the thin-walled sleeve parts after ion nitriding. To this end, the utility model proposes a tooling for ion nitriding of the inner hole of the thin-walled sleeve parts, in order to solve the above technical problems and improve the qualified rate of the finished workpieces of the thin-walled sleeve parts after ion nitriding. Summary of the invention
[0004] The purpose of the utility model is to overcome the defects in the prior art and provide a tool for ion nitriding treatment of the inner holes of thin-walled sleeve parts. When in use, a plurality of seat sleeves are laid on the cathode disk at intervals, the lower ends of a plurality of thin-walled sleeve part blanks to be ion nitrided are coaxially placed one by one on the upper end edge surface of the seat sleeve, a plurality of sleeves are sleeved one by one on the outer side of the thin-walled straight tube section of the thin-walled sleeve part blank, and then the inner hole wall surface of the thin-walled sleeve part blank is ion nitrided. Since a plurality of air holes are arranged on the seat sleeve at intervals, the nitrogen ion atmosphere generated after the nitrogen-containing gas is ionized can flow up and down in the inner hole cavity of the thin-walled sleeve part blank, so that the nitrogen ion atmosphere can be evenly distributed. In the inner hole cavity of the thin-walled sleeve parts blank, it is ensured that the inner hole wall surface of the finished thin-walled sleeve parts after ion nitriding treatment has a uniform nitriding layer, that is, the hardness uniformity of the inner hole wall surface of the finished thin-walled sleeve parts is ensured; during the ion nitriding treatment of the thin-walled sleeve parts blank, the sleeve sleeved on the outside of its thin-walled straight tube section can effectively transfer heat, so that the temperature of the thin-walled straight tube section will not be too high, and the sleeve also has a beam-forming effect on its thin-walled straight tube section, ensuring that the thin-walled straight tube section on the finished thin-walled sleeve parts will not have serious thermal deformation due to excessively high temperature, thereby significantly improving the qualified rate of the finished thin-walled sleeve parts after ion nitriding treatment; the overall structural design is simple, the preparation and implementation feasibility is high, and the practicability is strong.
[0005] To achieve the above-mentioned purpose, the technical solution of the utility model is to design a tool for ion nitriding treatment of the inner holes of thin-walled sleeve parts, including a seat sleeve and a sleeve. The seat sleeve has a cavity that passes through the upper and lower end surfaces. The seat sleeve is provided with a plurality of air holes at intervals. The upper end edge surface of the seat sleeve is matched with the lower end edge surface of the thin-walled sleeve part blank. The sleeve is matched with the thin-walled straight tube section on the thin-walled sleeve part blank, and the wall thickness of the sleeve is set to D and the height is set to H. The wall thickness of the thin-walled straight tube section on the thin-walled sleeve part blank is set to d and the height is set to h, then D>d, H≥h.
[0006] The utility model discloses a tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts. When in use, a plurality of seat sleeves are laid on a cathode plate at intervals, the lower ends of a plurality of thin-walled sleeve part blanks to be ion nitrided are coaxially placed on the upper edge surface of the seat sleeve in a one-to-one correspondence, a plurality of sleeves are sleeved on the outer sides of the thin-walled straight tube sections of the thin-walled sleeve part blanks in a one-to-one correspondence, and then the inner hole wall surface of the thin-walled sleeve part blanks is ion nitrided. Since a plurality of air holes are arranged at intervals on the seat sleeve, the nitrogen ion atmosphere generated after the nitrogen-containing gas is ionized can flow up and down in the inner hole cavity of the thin-walled sleeve part blank, so that the nitrogen ion atmosphere can be evenly distributed in the inner hole cavity of the thin-walled sleeve part blank. In the inner hole cavity, it is ensured that the inner hole wall surface of the finished thin-walled sleeve parts after ion nitriding treatment has a uniform nitriding layer, that is, the hardness uniformity of the inner hole wall surface of the finished thin-walled sleeve parts is ensured; in the ion nitriding treatment process of the thin-walled sleeve parts blank, the sleeve sleeved on the outside of its thin-walled straight tube section can effectively transfer heat, so that the temperature of the thin-walled straight tube section will not be too high, and the sleeve also has a beam-forming effect on its thin-walled straight tube section, ensuring that the thin-walled straight tube section on the finished thin-walled sleeve parts will not have serious thermal deformation due to excessively high temperature, thereby significantly improving the qualified rate of the finished thin-walled sleeve parts after ion nitriding treatment; the overall structural design is simple, the preparation and implementation feasibility is high, and the practicability is strong.
[0007] The preferred technical solution is that the plurality of air holes are longitudinal waist holes distributed circumferentially and spaced apart on the seat cover. The air holes with this structural design and distribution have a large total opening area while ensuring the rigidity of the seat cover, so that the nitrogen ion atmosphere generated after the nitrogen-containing gas is ionized can flow smoothly at both ends of the inner hole cavity of the thin-walled sleeve part blank, further ensuring the uniform distribution of the nitrogen ion atmosphere in the inner hole cavity of the thin-walled sleeve part blank.
[0008] A further preferred technical solution is that the wall thickness D of the sleeve is 3 to 5 times the wall thickness d of the thin-walled straight section on the thin-walled sleeve part blank. The thickness of the sleeve is reasonably designed to fully transfer the heat of the thin-walled straight section on the sleeve part blank to the sleeve, and ensure that the sleeve has good beam-forming properties for the thin-walled straight section on the sleeve part blank.
[0009] A further preferred technical solution is that the inner diameter of the sleeve is set to φR, and the inner diameter of the thin-walled straight section on the thin-walled sleeve part blank is set to Φr, then φR=Φr+(0.05-0.1mm). The inner diameter of the sleeve is slightly larger than the inner diameter of the thin-walled straight section on the thin-walled sleeve part blank, ensuring the convenience and smoothness of the sleeve when being sleeved or disassembled on the thin-walled straight section of the thin-walled sleeve part blank, and at the same time ensuring that the inner hole wall surface of the sleeve is basically in contact with the outer wall surface of the thin-walled straight section of the thin-walled sleeve part blank, which helps to further improve the heat conduction effect and beam-forming effect of the sleeve on the thin-walled straight section on the sleeve part blank.
[0010] A further preferred technical solution is that the inner circumference of the upper edge surface of the seat sleeve is provided with an annular step groove that sinks into the cavity, and the inner diameter φB of the horizontal bottom surface of the annular step groove is less than the outer diameter φa of the lower edge surface of the thin-walled sleeve part blank and less than the outer diameter φC of the horizontal bottom surface of the annular step groove. The annular step groove improves the convenience of positioning and installing the thin-walled sleeve part blank on the upper end of the seat sleeve during loading, and the inner and outer diameter dimensions of the horizontal bottom surface of the annular step groove are reasonably designed to ensure that the lower end of the thin-walled sleeve part blank can be smoothly inserted and placed inside the annular step groove at the upper end of the seat sleeve, which helps to improve the efficiency of loading the thin-walled sleeve part blank.
[0011] A further preferred technical solution is that the value range of φC is: φa+1mm~φa+3mm. The outer diameter φC of the horizontal bottom surface of the annular step groove is reasonably designed to ensure the smoothness of the loading and unloading of the thin-walled sleeve parts blank and the finished thin-walled sleeve parts, and at the same time ensure the stability of the thin-walled sleeve parts blank when plugged into the annular step groove at the upper end of the seat cover during loading, so as to avoid the thin-walled sleeve parts blank or the thin-walled sleeve parts finished product from shaking violently when moving with the seat cover.
[0012] A further preferred technical solution is that the lower end of the seat cover is provided with an annular boss extending outward, and the lower end surface of the annular boss is flush with the lower end surface of the seat cover. The annular boss effectively increases the contact area between the lower end surface of the seat cover and the cathode disk, that is, improves the placement stability of the seat cover on the cathode disk, and prevents the thin-walled sleeve part blank or thin-walled sleeve part finished product from tipping over due to unstable placement of the seat cover when it moves with the seat cover.
[0013] A further preferred technical solution is that the lower end of the seat sleeve is provided with an annular cone extending outward, the large-diameter end of the annular cone is located at the lower side, and the lower end surface of the annular cone is flush with the lower end surface of the seat sleeve. The annular cone effectively increases the contact area between the lower end surface of the seat sleeve and the cathode disk, that is, improves the placement stability of the seat sleeve on the cathode disk, and prevents the thin-walled sleeve part blank or thin-walled sleeve part finished product from tipping over due to unstable placement of the seat sleeve when it moves with the seat sleeve.
[0014] The advantages and beneficial effects of the utility model are:
[0015] 1. The utility model is a tooling for ion nitriding treatment of the inner hole of thin-walled sleeve parts. When in use, a plurality of seat sleeves are laid on the cathode disk at intervals, the lower ends of a plurality of thin-walled sleeve parts to be ion nitrided are coaxially placed on the upper edge surface of the seat sleeve in a one-to-one correspondence, and a plurality of sleeves are sleeved on the outer side of the thin-walled straight tube section of the thin-walled sleeve parts in a one-to-one correspondence, and then the inner hole wall surface of the thin-walled sleeve parts blank is ion nitrided. Since a plurality of air holes are arranged on the seat sleeve at intervals, the nitrogen ion atmosphere generated after the nitrogen-containing gas is ionized can flow up and down in the inner hole cavity of the thin-walled sleeve parts blank, so that the nitrogen ion atmosphere can be evenly distributed in the thin-walled sleeve parts blank. In the inner hole cavity, it is ensured that the inner hole wall surface of the finished thin-walled sleeve parts after ion nitriding treatment has a uniform nitriding layer, that is, the hardness uniformity of the inner hole wall surface of the finished thin-walled sleeve parts is ensured; in the ion nitriding treatment process of the thin-walled sleeve parts blank, the sleeve sleeved on the outside of its thin-walled straight tube section can effectively transfer heat, so that the temperature of the thin-walled straight tube section will not be too high, and the sleeve also has a beam-forming effect on its thin-walled straight tube section, ensuring that the thin-walled straight tube section on the finished thin-walled sleeve parts will not experience serious thermal deformation due to excessively high temperature, thereby significantly improving the qualified rate of the finished thin-walled sleeve parts after ion nitriding treatment; the overall structural design is simple, the preparation and implementation feasibility is high, and the practicability is strong.
[0016] 2. Some of the air holes are longitudinal waist holes distributed at intervals in the annular direction on the seat cover. The air holes with this structural design and distribution have a large total opening area under the premise of ensuring the rigidity of the seat cover, so that the nitrogen ion atmosphere generated by the ionization of the nitrogen-containing gas can flow smoothly at both ends of the inner hole cavity of the thin-walled sleeve part blank, further ensuring the uniform distribution of the nitrogen ion atmosphere in the inner hole cavity of the thin-walled sleeve part blank.
[0017] 3. The wall thickness D of the sleeve is 3 to 5 times the wall thickness d of the thin-walled straight section on the thin-walled sleeve part blank. The thickness of the sleeve is reasonably designed to fully transfer the heat of the thin-walled straight section on the sleeve part blank to the sleeve, and ensure that the sleeve has good beam-forming properties for the thin-walled straight section on the sleeve part blank.
[0018] 4. The inner diameter of the sleeve is set to φR, and the inner diameter of the thin-walled straight section on the thin-walled sleeve part blank is set to Φr, then φR = Φr + (0.05-0.1mm). The inner diameter of the sleeve is slightly larger than the inner diameter of the thin-walled straight section on the thin-walled sleeve part blank, ensuring the convenience and smoothness of the sleeve when being sleeved or disassembled on the thin-walled straight section of the thin-walled sleeve part blank, and at the same time ensuring that the inner hole wall of the sleeve is basically in contact with the outer wall of the thin-walled straight section of the thin-walled sleeve part blank, which helps to further improve the heat conduction effect and beam-forming effect of the sleeve on the thin-walled straight section on the sleeve part blank. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1It is a stereoscopic diagram of a tool used for ion nitriding treatment of inner holes of thin-walled sleeve parts in Example 1;
[0020] Figure 2 is a longitudinal cross-sectional view of the seat cover in Embodiment 1;
[0021] Figure 3 It is a longitudinal cross-sectional view of a tool for ion nitriding treatment of inner holes of thin-walled sleeve parts in Example 1 when used for nitriding of stepped thin-walled sleeve parts;
[0022] Figure 4 is a three-dimensional diagram of the seat cover in Example 2;
[0023] Figure 5 is a longitudinal sectional view of the seat cover in Embodiment 2;
[0024] Figure 6 It is a longitudinal cross-sectional view of a tool for ion nitriding treatment of inner holes of thin-walled sleeve parts in Example 2 when used for nitriding of stepped thin-walled sleeve parts;
[0025] Figure 7 is a longitudinal sectional view of the seat cover in Embodiment 3;
[0026] Figure 8 It is a longitudinal cross-sectional view of a tool used for ion nitriding treatment of the inner holes of thin-walled sleeve parts in Example 3 when being used for nitriding of straight thin-walled sleeve parts.
[0027] In the figure: 1, seat cover; 2, sleeve; 3, stepped thin-walled sleeve type parts blank; 4, straight-tube thin-walled sleeve type parts blank; 1-1, annular step groove; 1-2, air vent; 1-3, annular boss; 1-4, annular cone; 3-1, thin-walled straight-tube section; 3-2, annular boss section. DETAILED DESCRIPTION
[0028] The following is a further description of the specific implementation of the present invention in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.
[0029] Example 1
[0030] like Figures 1 to 3As shown, the utility model is a tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts, comprising a seat sleeve 1 and a sleeve 2. The seat sleeve 1 has a cavity penetrating the upper and lower end surfaces, and the seat sleeve 1 is provided with a plurality of air holes 1-2 at intervals. The upper end edge surface of the seat sleeve 1 is matched with the lower end edge surface of the thin-walled sleeve part blank, and the sleeve 2 is matched with the thin-walled straight tube section on the thin-walled sleeve part blank, and the wall thickness of the sleeve 2 is set to D and the height is set to H, and the wall thickness of the thin-walled straight tube section on the thin-walled sleeve part blank is set to d and the height is set to h, then D>d, H≥h.
[0031] Preferably, the plurality of ventilation holes 1 - 2 are longitudinal waist holes distributed on the seat cover 1 at intervals in an annular direction.
[0032] Further preferably, the wall thickness D of the sleeve 2 is 3 to 5 times the wall thickness d of the thin-walled straight tube section on the thin-walled sleeve-like part blank.
[0033] Further preferably, the inner diameter of the sleeve 2 is set to φR, and the inner diameter of the thin-walled straight section on the thin-walled sleeve-like part blank is set to Φr, then φR=Φr+(0.05-0.1mm).
[0034] Further preferably, the inner circumference of the upper end edge surface of the seat cover 1 is provided with an annular step groove 1-1 which sinks into the interior of its cavity, and the inner diameter φB of the horizontal bottom surface of the annular step groove 1-1 is less than the outer diameter φa of the lower end edge surface of the thin-walled sleeve part blank and less than the outer diameter φC of the horizontal bottom surface of the annular step groove 1-1.
[0035] Further preferably, the value range of φC is: φa+1mm~φa+3mm.
[0036] Example 2
[0037] like Figures 4 to 6 As shown, the utility model is a tool for ion nitriding treatment of the inner pores of thin-walled sleeve parts. The difference from the tool for ion nitriding treatment of the inner pores of thin-walled sleeve parts in Example 1 is that the lower end of the seat sleeve 1 is provided with an annular boss 1-3 extending outward, and the lower end surface of the annular boss 1-3 is flush with the lower end surface of the seat sleeve 1.
[0038] The utility model discloses a tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts using the following principles:
[0039] Taking the ion nitriding treatment of the inner hole wall surface of the stepped thin-walled sleeve type part blank 3 as an example, a plurality of seat sleeves 1 are laid on the cathode disk in the furnace of the ion nitriding furnace at intervals, and the spacing between adjacent seat sleeves 1 is 20 to 30 mm in front and back and left and right. Then, the annular boss sections 3-2 at the lower ends of the plurality of stepped thin-walled sleeve type part blanks 3 to be ion nitrided are placed one by one on the annular step grooves 1-1 at the upper ends of the plurality of seat sleeves 1, and the plurality of sleeves 2 are sleeved one by one on the outer sides of the thin-walled straight cylinder sections 3-1 at the upper ends of the stepped thin-walled sleeve type part blanks 3 (see attached Figure 3 , Attachment Figure 6 ); perform ion nitriding treatment. After the ion nitriding treatment is completed, the sleeve 2 is removed and the finished stepped thin-walled sleeve parts are removed from the seat sleeve 1. Then, the cathode disk, the seat sleeve 1 and the sleeve 2 are put into the ion nitriding treatment of the next batch of stepped thin-walled sleeve parts blanks 3.
[0040] Example 3
[0041] like Figures 7-8 As shown, the utility model is a tool for ion nitriding treatment of the inner pores of thin-walled sleeve parts. The difference from the tool for ion nitriding treatment of the inner pores of thin-walled sleeve parts in Example 1 is that the lower end of the seat sleeve 1 is provided with an annular cone 1-4 extending outward, the large-diameter end of the annular cone 1-4 is located on the lower side, and the lower end surface of the annular cone 1-4 is flush with the lower end surface of the seat sleeve 1.
[0042] The utility model discloses a tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts using the following principles:
[0043] Taking the ion nitriding treatment of the inner hole wall surface of the straight thin-walled sleeve type part blank 4 as an example, a plurality of seat sleeves 1 are laid on the cathode disk in the furnace of the ion nitriding furnace at intervals, and the spacing between adjacent seat sleeves 1 is 20 to 30 mm in front and back and left and right. Then, the lower edge surfaces of a plurality of straight thin-walled sleeve type part blanks 4 to be ion nitrided are placed one by one on the annular step grooves 1-1 at the upper ends of a plurality of seat sleeves 1, and a plurality of sleeves 2 are sleeved one by one on the outside of the straight thin-walled sleeve type part blank 4 (see attached Figure 8 ); perform ion nitriding treatment. After the ion nitriding treatment is completed, the sleeve 2 is removed and the finished straight thin-walled sleeve parts are removed from the seat sleeve 1. Then, the cathode disk, the seat sleeve 1 and the sleeve 2 are put into the ion nitriding treatment of the next batch of straight thin-walled sleeve parts blanks 4.
[0044] The utility model discloses a tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts. When in use, a plurality of seat sleeves are laid on a cathode plate at intervals, the lower ends of a plurality of thin-walled sleeve part blanks to be ion nitrided are coaxially placed on the upper edge surface of the seat sleeve in a one-to-one correspondence, a plurality of sleeves are sleeved on the outer sides of the thin-walled straight tube sections of the thin-walled sleeve part blanks in a one-to-one correspondence, and then the inner hole wall surface of the thin-walled sleeve part blanks is ion nitrided. Since a plurality of air holes are arranged at intervals on the seat sleeve, the nitrogen ion atmosphere generated after the nitrogen-containing gas is ionized can flow up and down in the inner hole cavity of the thin-walled sleeve part blank, so that the nitrogen ion atmosphere can be evenly distributed in the inner hole cavity of the thin-walled sleeve part blank. In the inner hole cavity, it is ensured that the inner hole wall surface of the finished thin-walled sleeve parts after ion nitriding treatment has a uniform nitriding layer, that is, the hardness uniformity of the inner hole wall surface of the finished thin-walled sleeve parts is ensured; in the ion nitriding treatment process of the thin-walled sleeve parts blank, the sleeve sleeved on the outside of its thin-walled straight tube section can effectively transfer heat, so that the temperature of the thin-walled straight tube section will not be too high, and the sleeve also has a beam-forming effect on its thin-walled straight tube section, ensuring that the thin-walled straight tube section on the finished thin-walled sleeve parts will not have serious thermal deformation due to excessively high temperature, thereby significantly improving the qualified rate of the finished thin-walled sleeve parts after ion nitriding treatment; the overall structural design is simple, the preparation and implementation feasibility is high, and the practicability is strong.
[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A tool for ion nitriding treatment of inner holes of thin-walled sleeve parts, characterized in that: The invention comprises a seat cover (1) and a sleeve (2), wherein the seat cover (1) has a cavity penetrating the upper and lower end surfaces, and the seat cover (1) is provided with a plurality of air holes (1-2) at intervals, the upper edge surface of the seat cover (1) is matched with the lower edge surface of a thin-walled sleeve-like part blank, and the sleeve (2) is matched with a thin-walled straight tube section on the thin-walled sleeve-like part blank, and the wall thickness of the sleeve (2) is set to D and the height is set to H, and the wall thickness of the thin-walled straight tube section on the thin-walled sleeve-like part blank is set to d and the height is set to h, then D>d, H≥h.
2. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts as claimed in claim 1, characterized in that: Some of the ventilation holes (1-2) are longitudinal waist holes distributed at intervals in an annular direction on the seat cover (1).
3. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts as claimed in claim 2, characterized in that: The wall thickness D of the sleeve (2) is 3 to 5 times the wall thickness d of the thin-walled straight tube section on the thin-walled sleeve-like part blank.
4. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts as claimed in claim 3, characterized in that: The inner diameter of the sleeve (2) is set to φR, and the inner diameter of the thin-walled straight section on the thin-walled sleeve-like part blank is set to Φr, then φR=Φr+(0.05-0.1mm).
5. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts as claimed in claim 4, characterized in that: The inner circumference of the upper edge surface of the seat sleeve (1) is provided with an annular step groove (1-1) that sinks into the interior of its cavity, and the inner diameter φB of the horizontal bottom surface of the annular step groove (1-1) is less than the outer diameter φa of the lower edge surface of the thin-walled sleeve part blank and less than the outer diameter φC of the horizontal bottom surface of the annular step groove (1-1).
6. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts as claimed in claim 5, characterized in that: The value range of φC is: φa+1mm~φa+3mm.
7. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts according to any one of claims 1 to 6, characterized in that: The lower end of the seat cover (1) is provided with an annular boss (1-3) extending outward, and the lower end surface of the annular boss (1-3) is flush with the lower end surface of the seat cover (1).
8. The tooling for ion nitriding treatment of inner holes of thin-walled sleeve parts according to any one of claims 1 to 6, characterized in that: The lower end of the seat cover (1) is provided with an annular cone (1-4) extending outward, the large-diameter end of the annular cone (1-4) is located at the lower side, and the lower end surface of the annular cone (1-4) is flush with the lower end surface of the seat cover (1).