Method for reducing heat treatment deformation of cycloidal-pin wheel

Abstract

The invention discloses a method for reducing heat treatment deformation of a cycloidal-pin wheel, which comprises the following steps: performing isothermal normalizing on a blank, processing the blank into a cycloidal-pin wheel blank, and cleaning residual greasy dirt; a plurality of cycloidal-pin wheel blanks are stacked and assembled, the assembled cycloidal-pin wheel blanks are put into a box-type multi-purpose furnace, carburizing and quenching treatment is carried out in a protective atmosphere in a temperature rise and heat preservation heating mode, and in the quenching process, after the carbon potential is controlled to be 0.8 + / -0.05%, the cycloidal-pin wheel blanks are cooled in quenching oil; and after cooling, residual quenching oil is cleaned away, a plurality of cycloidal-pin wheel blanks are subjected to tempering treatment after being stacked and assembled again, and the cycloidal-pin wheel blanks are air-cooled to the room temperature after tempering. According to the method, the shape characteristics of the cycloidal pin wheel and the carburizing and quenching deformation rule serve as the basis for reducing the heat treatment deformation of the cycloidal pin wheel, the deformation of trisection holes during carburizing and quenching is controlled by improving a carburizing and quenching charging mode, and then the buckling deformation of the end face during carburizing and quenching is controlled by improving a low-temperature tempering charging mode and a low-temperature tempering mode. Therefore, the heat treatment deformation of the cycloidal gear is effectively controlled.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment deformation of cycloidal pin wheels, and in particular to a method for reducing heat treatment deformation of cycloidal pin wheels. Background Art

[0002] The cycloid pinwheel shape of the RV reducer of the large-load industrial robot. As one of the core parts of the RV reducer, the cycloid pinwheel is required to have excellent wear resistance and contact fatigue resistance. At present, the cycloid pinwheel adopts the heat treatment method of low-carbon alloy steel carburizing quenching + low-temperature tempering. After the conventional box-type multi-purpose furnace is used for carburizing quenching + low-temperature tempering, the warping deformation of the three-divided hole and the end face of the cycloid pinwheel is relatively large, and the maximum can reach 0.50mm. The yield rate that meets the heat treatment deformation of the three-divided hole and the end face of the cycloid pinwheel is ≤0.20mm is only about 40%, which increases the production cost of the product. Summary of the invention

[0003] In view of the above defects or shortcomings, an object of the present invention is to provide a method for reducing the heat treatment deformation of a cycloidal pin wheel.

[0004] To achieve the above purpose, the technical solution of the present invention is:

[0005] A method for reducing heat treatment deformation of a cycloidal pinwheel comprises the following steps:

[0006] Step 1: After isothermal normalizing the blank, process it into a cycloidal pinwheel blank and clean the residual oil stains;

[0007] Step 2: stack and assemble a plurality of cycloidal pinwheel blanks, load them into a box-type multi-purpose furnace, and heat them in a protective atmosphere by carburizing and quenching. During the quenching process, the carbon potential is controlled to 0.8±0.05%, and then cooled in quenching oil;

[0008] Step 3: After cooling, clean the residual quenching oil, reassemble multiple cycloidal pinwheel blanks, and perform tempering. After tempering, air cool to room temperature.

[0009] The step 2 specifically includes:

[0010] In a protective atmosphere, heat to 920±5℃ and keep the temperature constant for 20 minutes, and control the carbon potential at 0.4±0.05%; then increase the carbon potential at 920±5℃ and raise the carbon potential to 1.20±0.05%;

[0011] Keep the temperature at 920±5℃, perform strong penetration for 440min, control the carbon potential at 1.20±0.05%, then continue to keep the temperature at 920±5℃ for diffusion for 180min, control the carbon potential at 1.0±0.05%;

[0012] Cool down to 840±5℃, and the carbon potential drops to 0.8±0.05%. Keep at 840±5℃ for 40 minutes, and the carbon potential is controlled at 0.8±0.05%.

[0013] Finally, cool in quenching oil at 60-80℃ for 30min.

[0014] Each time, eight cycloid pin wheel blanks are stacked and assembled and then placed in a box-type multi-purpose furnace.

[0015] The carburizing and quenching furnace comprises: a lower end cover, the lower end cover is evenly arranged with three mounting holes, a connecting rod is installed in the mounting hole, the connecting rod and the cycloidal pinwheel blank are sleeved on the connecting rod, and a gasket is arranged between the cycloidal pinwheel blanks.

[0016] An upper end cover for pressing the cycloidal pinwheel blank is arranged at the top end of the connecting rod. The upper end cover is an annular structure and is fixedly mounted on the connecting rod by a nut.

[0017] When the cycloid pinwheel blank is sleeved on the connecting rod, the cycloid pinwheel blank A is placed downward, and the three-divided hole is aligned with the three-divided holes of the upper and lower end covers.

[0018] In the step 3, the tempering temperature of the tempering treatment is 160±5° C. and the time is 360 min.

[0019] The step three specifically includes:

[0020] When loading the furnace for low-temperature tempering, the cycloidal pinwheel blank is turned 180°, placed with the A side facing upward, and clamped with a connecting rod and a nut. It is first tempered at 160±5°C for 240min and then taken out. The cycloidal pinwheel blank is clamped with a connecting rod and a nut again and tempered at 160±5°C for 120min, and then taken out and air-cooled to room temperature.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] The present invention provides a method for reducing the heat treatment deformation of a cycloidal pinwheel. The shape characteristics of the cycloidal pinwheel and the deformation law of carburizing and quenching are used as the basis for reducing the heat treatment deformation of the cycloidal pinwheel. The deformation of the three-divided hole during carburizing and quenching is first controlled by improving the carburizing and quenching furnace loading method, and then the end face warping deformation during carburizing and quenching is controlled by improving the low-temperature tempering furnace loading method and the low-temperature tempering method, so that the heat treatment deformation of the cycloidal wheel is effectively controlled. The present invention is a technical method that can achieve the heat treatment deformation of the three-divided hole and the end face warping of the cycloidal wheel to be ≤0.20mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flow chart of a method for reducing heat treatment deformation of a cycloidal pinwheel according to the present invention;

[0024] Figure 2 It is a schematic diagram of the structure of the cycloid pinwheel blank of the present invention;

[0025] Figure 3 It is a schematic diagram of the cycloidal pinwheel carburizing and quenching furnace structure of the present invention;

[0026] Figure 4 It is a schematic diagram of the structure of the lower end cover of the present invention;

[0027] Figure 5 It is a schematic diagram of the structure of the gasket of the present invention;

[0028] Figure 6 It is a schematic diagram of a low temperature tempering furnace according to the present invention. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the protection scope of the present invention.

[0030] like Figure 1 As shown, the present invention provides a method for reducing the heat treatment deformation of a cycloidal pin wheel, comprising the following steps:

[0031] Step 1: After isothermal normalizing the blank, the blank is processed into a cycloidal pinwheel blank 3, and residual oil is cleaned;

[0032] Isothermal normalizing is performed on the forged billet of material 8620H, requiring the billet hardness to be controlled within HB153-185, and obtaining uniform ferrite and pearlite structure, and then the billet is processed into Figure 2 The cycloid pinwheel blank 3 shown is cleaned of the oil stains remaining on the surface of the cycloid pinwheel.

[0033] Step 2: stack and assemble a plurality of cycloidal pinwheel blanks, load them into a box-type multi-purpose furnace, and heat them in a protective atmosphere by carburizing and quenching. During the quenching process, the carbon potential is controlled to 0.8±0.05%, and then cooled in quenching oil;

[0034] The step 2 specifically includes:

[0035] In a protective atmosphere, heat to 920±5℃ and keep the temperature constant for 20 minutes, and control the carbon potential at 0.4±0.05%; then increase the carbon potential at 920±5℃ and raise the carbon potential to 1.20±0.05%;

[0036] Keep the temperature at 920±5℃, perform strong penetration for 440min, control the carbon potential at 1.20±0.05%, then continue to keep the temperature at 920±5℃ for diffusion for 180min, control the carbon potential at 1.0±0.05%;

[0037] Cool down to 840±5℃, and the carbon potential drops to 0.8±0.05%. Keep at 840±5℃ for 40 minutes, and the carbon potential is controlled at 0.8±0.05%.

[0038] Finally, cool in quenching oil at 60-80℃ for 30min.

[0039] For example, Figure 3 , 4 As shown, in the present invention, the carburizing and quenching furnace comprises: a lower end cover 1, the lower end cover 1 is evenly arranged with three mounting holes, a connecting rod 5 is installed in the mounting hole, the connecting rod 5 and the cycloidal pinwheel blank 3 are sleeved on the connecting rod 5, and a gasket 2 is arranged between the cycloidal pinwheel blank 3. Figure 5 As shown, an upper end cover 4 for pressing the cycloidal pinwheel blank 3 is provided at the top end of the connecting rod 5 , and the upper end cover 4 is an annular structure, and the upper end cover 4 is fixedly mounted on the connecting rod 5 by a nut 6 .

[0040] In the present invention, Figure 3 As shown, each time eight cycloidal pinwheel blanks 3 are stacked and assembled and loaded into the carburizing and quenching furnace of the box-type multi-purpose furnace, when the cycloidal pinwheel blank 3 is sleeved on the connecting rod 5, the cycloidal pinwheel blank 3A is placed face down, and the three-divided holes are aligned with the three-divided holes of the lower end cover 1 and the upper end cover 4, which is conducive to the flow of carburizing atmosphere and quenching oil, and ensures the carburizing and quenching quality of the three-divided holes.

[0041] according to Figure 3 Schematic diagram of carburizing and quenching furnace assembly, from bottom to top: lower end cover 1 - gasket 2 - cycloidal pin wheel blank 3 - gasket 2 - cycloidal pin wheel blank 3 - gasket 2 - cycloidal pin wheel blank 3 - gasket 2 - cycloidal pin wheel blank 3 - gasket 2 - cycloidal pin wheel blank 3 - gasket 2 - cycloidal pin wheel blank 3 - gasket 2 - cycloidal pin wheel blank 3 - upper end cover 4, and fixed with connecting rod 5 and nut 6, requiring cycloidal pin wheel blank 3A to be placed face down, gasket 2 stuck in the end face groove, and the three-divided hole aligned with the three-divided hole of lower end cover 1 and upper end cover 4.

[0042] Step 3: After cooling, clean the residual quenching oil, reassemble multiple cycloidal pinwheel blanks, and perform tempering. After tempering, air cool to room temperature.

[0043] The step three specifically includes:

[0044] After carburizing and quenching, clean the two ends of the cycloid pinwheel and press Figure 6 Schematic diagram of low-temperature tempering furnace assembly, turn the cycloidal pinwheel blank 3 180°, place it with face A facing upward, clamp the cycloidal pinwheel blank 3 with connecting rod 5 and nut 6, temper it at 160±5℃ for 240min and then take it out, clamp the cycloidal pinwheel blank 3 with connecting rod 5 and nut 6 again and continue tempering it at 160±5℃ for 120min, take it out and air cool it to room temperature, disassemble the low-temperature tempering tooling and take out the cycloidal pinwheel blank 3, the heat treatment deformation of the cycloidal pinwheel three-divided hole and the end face warping can be controlled within ≤0.20mm.

[0045] The method of the present invention takes the shape characteristics of the cycloidal pinwheel and the deformation law of carburizing and quenching as the basis for reducing the heat treatment deformation of the cycloidal pinwheel, firstly controls the deformation of the three-divided hole during carburizing and quenching by improving the carburizing and quenching furnace loading method, and then controls the end face warping deformation during carburizing and quenching by improving the low-temperature tempering furnace loading method and the low-temperature tempering method, so that the heat treatment deformation of the cycloidal pinwheel is effectively controlled, and is a method that can achieve the heat treatment deformation of the three-divided hole and the end face warping of the cycloidal pinwheel is ≤0.20mm. The problem of large heat treatment deformation of the three-divided hole and the end face warping of the existing cycloidal pinwheel and low yield is solved. The technical method of the present invention is adopted, and the technical measures such as the carburizing and quenching furnace loading method, the low-temperature tempering furnace loading method and the low-temperature tempering method of the cycloidal pinwheel are respectively improved, so that the heat treatment deformation of the three-divided hole and the end face warping of the cycloidal pinwheel is ≤0.20mm, so that the qualified rate is greatly improved to more than 98%.

[0046] It is obvious to those skilled in the art that the above-mentioned specific examples are only preferred embodiments of the present invention. Therefore, the improvements and changes that may be made by those skilled in the art to certain parts of the present invention still embody the principles of the present invention and achieve the purpose of the present invention, and all belong to the scope of protection of the present invention.

Claims

1. A method for reducing heat treatment deformation of a cycloid pinwheel, characterized in that: The following steps are involved: Step 1: After isothermal normalizing the blank, the blank is processed into a cycloidal pinwheel blank (3), and residual oil is cleaned; Step 2, stacking and assembling a plurality of cycloidal pinwheel blanks (3), loading them into a box-type multi-purpose furnace, and performing carburizing and quenching treatment by heating and preserving in a protective atmosphere. During the quenching process, after the carbon potential is controlled to 0.8±0.05%, the blanks are cooled in quenching oil; Step 3: After cooling, clean the residual quenching oil, stack and assemble a plurality of cycloidal pinwheel blanks (3), perform tempering, and air-cool to room temperature after tempering.

2. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 1, characterized in that: The step 2 specifically includes: In a protective atmosphere, heat to 920±5℃ and keep the temperature constant for 20 minutes, and control the carbon potential at 0.4±0.05%; then increase the carbon potential at 920±5℃ and raise the carbon potential to 1.20±0.05%; Keep the temperature at 920±5℃, perform strong penetration for 440min, control the carbon potential at 1.20±0.05%, then continue to keep the temperature at 920±5℃ for diffusion for 180min, control the carbon potential at 1.0±0.05%; Cool down to 840±5℃, and the carbon potential drops to 0.8±0.05%. Keep at 840±5℃ for 40 minutes, and the carbon potential is controlled at 0.8±0.05%. Finally, cool in quenching oil at 60-80℃ for 30min.

3. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 1 or 2, characterized in that: Each time, eight cycloid pinwheel blanks (3) are stacked and assembled and then loaded into a box-type multi-purpose furnace.

4. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 1, characterized in that: The carburizing and quenching furnace comprises: a lower end cover (1), the lower end cover (1) having three evenly arranged mounting holes, a connecting rod (5) being mounted in the mounting hole, the connecting rod (5), the cycloidal pinwheel blank (3) being sleeved on the connecting rod (5), and a gasket (2) being arranged between the cycloidal pinwheel blank (3).

5. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 4, characterized in that: An upper end cover (4) for pressing the cycloidal pinwheel blank (3) is provided at the top end of the connecting rod (5); the upper end cover (4) is an annular structure and is fixedly mounted on the connecting rod (5) via a nut (6).

6. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 5, characterized in that: When the cycloid pinwheel blank (3) is sleeved on the connecting rod (5), the cycloid pinwheel blank (3) is placed with the A surface facing downward, and the three-divided hole is aligned with the three-divided holes of the upper and lower end covers (4, 1).

7. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 6, characterized in that: In the step 3, the tempering temperature of the tempering treatment is 160±5° C. and the time is 360 min.

8. The method for reducing heat treatment deformation of a cycloid pinwheel according to claim 7, characterized in that: The step three specifically includes: When loading the furnace for low-temperature tempering, the cycloidal pinwheel blank (3) is turned over 180° and placed with the A side facing upward. The cycloidal pinwheel blank (3) is clamped by a connecting rod (5) and a nut (6). The cycloidal pinwheel blank (3) is first tempered at 160±5°C for 240 minutes and then taken out. The cycloidal pinwheel blank (3) is clamped by a connecting rod (5) and a nut (6) again and tempered at 160±5°C for 120 minutes. The blank is then taken out and air-cooled to room temperature.

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