Cotton picking spindle and preparation method thereof

Abstract

The present invention discloses a cotton picking spindle and a preparation method thereof, which relates to the technical field of agricultural machinery, including a cotton picking spindle body, on the surface of which a Si-rich carbon-based wear-resistant thick coating is arranged, the Si-rich carbon-based wear-resistant thick coating comprises a Si transition layer and a cotton picking spindle working layer, and the cotton picking spindle working layer comprises a plurality of layers of Si-rich doped carbon-based coatings and pure carbon-based coatings alternately arranged; the present invention replaces the traditional carburizing and electroplating hard chromium processes by preparing a Si-rich carbon-based thick coating on the surface of the cotton picking spindle, thereby meeting the requirements of the wear resistance of the cotton picking spindle. The preparation process comprises flexible sandblasting deburring sandblasting, surface pre-cleaning, metal grid plasma enhanced preparation of thick coating and other processes, and the prepared coating has a thickness of 10 to 15 μm, a microhardness of 1200 to 1600 HV, and a dry friction coefficient of less than 0.2.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural machinery, in particular to a cotton picking spindle and a preparation method thereof. Background Art

[0002] Cotton picking in my country has been widely mechanized, and cotton pickers are important key equipment. Picking spindles are the core components of cotton pickers. Each cotton picker needs to be equipped with more than 2,500 picking spindles. It costs more than 200,000 yuan to replace a picking spindle. Improving the reliability and service life of picking spindles can not only improve the operating efficiency of cotton pickers, but also reduce the production cost of cotton picking.

[0003] The cotton picking spindle utilizes the curled fiber characteristics of cotton when working, hooks the cotton with the hook teeth on the spindle, and winds the cotton on the working surface of the spindle through the rotation of the spindle around its axis, and finally sends it to the doffing disk for doffing. The hook teeth on the spindle are in a state of friction and wear with the cotton support rods and other debris for a long time, and the friction force applied by the doffing disk during the doffing process will also cause the surface wear of the spindle. In addition, the tip of the hook teeth of the cotton picking spindle is very sharp, and the processing damage caused by traditional machining may result in a high surface roughness. The tip of the cotton picking spindle often produces additional residual stress and bears higher loads, which leads to the failure of the cotton picking spindle.

[0004] At present, domestic cotton picking spindles are usually made of 20Cr, 20CrMnTi, 20Mn and other materials. In order to improve the wear resistance of the cotton picking spindle surface, carburizing treatment is first performed on the surface of the spindle, and then electroplating hard chrome is a common process. However, in recent years, my country's restrictions on the high-energy consumption and high-pollution electroplating hard chrome industry have had a great impact on the production of cotton picking spindles.

[0005] In summary, providing a new type of wear-resistant cotton picking spindle is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] The purpose of the present invention is to provide a cotton picking spindle and a preparation method thereof to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] The present invention provides a cotton picking spindle, comprising a cotton picking spindle body, wherein hook teeth are distributed on the upper end of the cotton picking spindle body, and a Si-rich carbon-based wear-resistant thick coating is provided on the surface of the cotton picking spindle body, wherein the Si-rich carbon-based wear-resistant thick coating comprises a Si transition layer and a cotton picking spindle working layer, wherein the Si transition layer is arranged between the surface of the cotton picking spindle body and the cotton picking spindle working layer, and the cotton picking spindle working layer comprises multiple layers of Si-rich doped carbon-based coatings and pure carbon-based coatings alternately arranged.

[0009] Preferably, the thickness of the Si transition layer is 2-3 μm.

[0010] Preferably, the total thickness of the Si-rich doped carbon-based coating and the pure carbon-based coating is 8-12 μm.

[0011] Preferably, the Si-rich doped carbon-based coating and the pure carbon-based coating are each provided with 4-6 layers.

[0012] Based on the above-mentioned cotton picking spindle, the present invention also provides a method for preparing the cotton picking spindle, comprising the following steps:

[0013] 1) Flexible sandblasting of cotton picking spindles: The cotton picking spindles are pre-treated by flexible wet sandblasting; when sandblasting, the spindles are placed in the sandblasting machine for sandblasting;

[0014] 2) Pre-cleaning of cotton picking spindles: put the sandblasted cotton picking spindles into an ultrasonic cleaning tank, fix the bottom on a rotating seat, and the cleaning tank contains a degreasing cleaning agent. Turn on the ultrasonic generator during cleaning, and the cleaning brush and cotton picking spindles can rotate. The surface pollutants and residual sand particles are removed by ultrasonic vibration and brushes. Use compressed air to blow dry the cotton picking spindles after cleaning, and put them into a heat preservation oven for drying;

[0015] 3) Cotton picking ingots are loaded into the furnace: the cleaned and dried cotton picking ingots are hung with their tips facing downwards in a metal frame, with a distance of more than 2cm between the ingots. A 80-200 mesh molybdenum wire mesh is used to wrap the outside of the frame to form a metal grid cage. The metal grid cage is connected to the negative pole of the pulse power supply with a wire and is insulated from the vacuum chamber; the positive pole of the pulse power supply is connected to the side wall of the vacuum chamber;

[0016] 4) Ion bombardment cleaning of cotton picking finger surface: vacuum chamber is evacuated to 3X10 -3 After Pa, inert gas is introduced with a gas flow rate of 50-500sccm, and the pulse power supply is turned on with a voltage of 500-2000V, a current of 20-80A, and a frequency of 200-600Hz for 10-60min;

[0017] 5) Preparation of transition layer for cotton picking: adjust the argon flow rate to 100-500sccm, introduce silane gas, the gas flow rate is 5-50sccm, the pulse power supply voltage is adjusted to 800-1500V, the current is 40-80A, the frequency is 200-400Hz, and it lasts for 10-25min;

[0018] 6) Preparation of cotton picking spindle working layer: adjust the argon flow rate to 50-300sccm, keep the silane gas flow rate unchanged, introduce acetylene gas, the acetylene gas flow rate is 50-200sccm, adjust the pulse power supply voltage to 1000-1500V, the current is 20-100A, the frequency is 300-600Hz, and continue for 10-20min to prepare Si-rich doped carbon-based coating; turn off the silane gas, keep other conditions unchanged, and continue for 10-20min to prepare pure carbon-based coating; Si-rich doped carbon-based coating and pure carbon-based coating are alternately deposited;

[0019] 7) The cotton picking spindle is taken out of the furnace: After the coating deposition is completed, the cotton picking spindle is cooled in the vacuum chamber with the furnace. When the vacuum chamber temperature is lower than 50°C, the vacuum chamber door is opened and the cotton picking spindle is taken out

[0020] Preferably, in step 1), the sand material is 80-200 mesh flexible polymer sand, and the sandblasting pressure is 0.3-0.6 MPa; the spray gun mouth in the sandblasting machine is 5-30 cm away from the picking ingot for sandblasting, and the sand jet flow is cleaned along the direction of the hook tooth gap, and each picking ingot is cleaned for 10-90 seconds.

[0021] Preferably, in step 3), the cotton picking spindles are suspended in a metal frame by spindle fixing wires, and the metal frame is cylindrical.

[0022] Preferably, the bonding strength of the Si-rich carbon-based wear-resistant thick coating on the surface of the cotton picking spindle body is greater than 40N, the microhardness of the Si-rich carbon-based wear-resistant thick coating is 1200-1600HV, and the dry friction coefficient between the Si-rich carbon-based wear-resistant thick coating and the Si3N4 ball is less than 0.2.

[0023] Compared with the prior art, the present invention has achieved the following beneficial technical effects:

[0024] The cotton picking spindle and preparation method provided by the present invention prepare a multi-layer Si-rich carbon-based wear-resistant thick coating on the surface of the cotton picking spindle, replacing the traditional carburizing and hard chromium electroplating process to meet the wear resistance requirements of the cotton picking spindle. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 This is an appearance diagram of a cotton picking spindle in the present invention;

[0027] Figure 2This is a schematic diagram of cleaning the cotton picking spindles in the present invention;

[0028] Figure 3 It is a schematic diagram of preparing the Si-rich carbon-based wear-resistant thick coating in the present invention;

[0029] Figure 4 Schematic diagram of the cross section of the Si-rich carbon-based wear-resistant thick coating of the present invention;

[0030] Among them, 1 is the cotton picking spindle body, 2 is the hook tooth, 3 is the ultrasonic cleaning tank, 4 is the cleaning agent, 5 is the cleaning brush, 6 is the upper end of the cotton picking spindle body, 7 is the cleaning brush holder, 8 is the rotating seat, 9 is the vacuum system, 10 is the metal grid cage, 11 is the spindle fixing wire, 12 is the pulse power supply, 13 is the vacuum chamber, 14 is the insulating base, 15 is the air supply system, 16 is the Si transition layer, 17 is the Si-rich doped carbon-based coating, and 18 is the pure carbon-based coating. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of 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 scope of protection of the present invention.

[0032] The purpose of the present invention is to provide a cotton picking spindle and a preparation method thereof, so as to solve the problems existing in the prior art.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The cotton picking spindles in this embodiment are as follows: Figure 1 , Figure 4 As shown, it includes a cotton picking spindle body 1, the upper end 6 of the cotton picking spindle body is distributed with hook teeth 2, the surface of the cotton picking spindle body 1 is provided with a Si-rich carbon-based wear-resistant thick coating, the Si-rich carbon-based wear-resistant thick coating includes a Si transition layer 16 and a cotton picking spindle working layer, the Si transition layer 16 is arranged between the surface of the cotton picking spindle body 1 and the cotton picking spindle working layer, the cotton picking spindle working layer includes multiple layers of Si-rich doped carbon-based coatings 17 and pure carbon-based coatings 18 alternately arranged.

[0035] In this specific embodiment, the thickness of the Si transition layer 16 is 2-3 μm; the total thickness of the Si-rich doped carbon-based coating 17 and the pure carbon-based coating 18 is 8-12 μm.

[0036] In this specific embodiment, the Si-rich doped carbon-based coating 17 and the pure carbon-based coating 18 are each provided with 4-6 layers.

[0037] The present invention also provides a method for preparing the cotton picking spindle, comprising the following steps:

[0038] 1) Flexible sandblasting of cotton picking spindles: The cotton picking spindles are pre-treated by flexible wet sandblasting; when sandblasting, the spindles are placed in the sandblasting machine for sandblasting;

[0039] 2) Pre-cleaning of cotton picking spindles: Figure 2 As shown, the cotton picking spindle after sandblasting is placed in an ultrasonic cleaning tank 3, the bottom of which is fixed on a rotating seat 8, the cleaning tank contains a degreasing cleaning agent 4, the ultrasonic generator is turned on during cleaning, the cleaning brush 5 is set on the cleaning brush seat 7, the cleaning brush 5 and the cotton picking spindle can both rotate, and the surface pollutants and residual sand particles are removed by ultrasonic vibration and the brush; the cotton picking spindle after cleaning is dried with compressed air, and then placed in a heat preservation oven for drying;

[0040] 3) Cotton picking and ingot loading: Figure 3 As shown, the cotton picking spindles after cleaning and drying are suspended in a metal frame with their tips facing downwards, with the distance between the picking spindles being more than 2 cm, and the outside of the frame is completely wrapped with a molybdenum wire mesh of 80-200 mesh to form a metal grid cage 10, the bottom of the metal grid cage 10 is an insulating base 14, the metal grid cage 10 is connected to the negative pole of the pulse power supply 12 by a wire, and is insulated from the vacuum chamber 13; the positive pole of the pulse power supply 12 is connected to the side wall of the vacuum chamber 13;

[0041] 4) Ion bombardment cleaning of cotton picking finger surface: evacuate the vacuum chamber 13 to 3X10 -3 After Pa, an inert gas is introduced through the gas supply system 15, with a gas flow rate of 50-500 sccm, and the pulse power supply 12 is turned on with a voltage of 500-2000 V, a current of 20-80 A, and a frequency of 200-600 Hz for 10-60 min;

[0042] 5) Preparation of transition layer for cotton picking: adjust the argon flow rate to 100-500sccm, introduce silane gas, the gas flow rate is 5-50sccm, the pulse power supply 12 voltage is adjusted to 800-1500V, the current is 40-80A, the frequency is 200-400Hz, and it lasts for 10-25min;

[0043] 6) Preparation of the working layer for cotton picking: adjust the argon flow rate to 50-300sccm, keep the silane gas flow rate unchanged, introduce acetylene gas, the acetylene gas flow rate is 50-200sccm, adjust the pulse power supply 12 voltage to 1000-1500V, the current to 20-100A, the frequency to 300-600Hz, and continue for 10-20min to prepare the Si-rich doped carbon-based coating 17; turn off the silane gas, keep other conditions unchanged, and continue for 10-20min to prepare the pure carbon-based coating 18; the Si-rich doped carbon-based coating 17 and the pure carbon-based coating 18 are alternately deposited;

[0044] 7) The cotton picking spindles are taken out of the furnace: After the coating deposition is completed, the cotton picking spindles are cooled in the vacuum chamber 13 along with the furnace. After the temperature of the vacuum chamber 13 is lower than 50° C., the door of the vacuum chamber 13 is opened and the cotton picking spindles are taken out.

[0045] In this specific embodiment, in step 1), the sand material is 80-200 mesh flexible polymer sand, and the sandblasting pressure is 0.3-0.6MPa; the spray gun in the sandblasting machine is 5-30cm away from the ingot for sandblasting, and the spray sand flow is cleaned along the gap direction of the hook teeth 2 ( Figure 1 The middle arrow shows the sandblasting direction), and each ingot is cleaned for 10-90 seconds.

[0046] In step 3), the cotton picking spindles are suspended in a metal frame by spindle fixing wires 11, and the metal frame is cylindrical.

[0047] The bonding strength of the Si-rich carbon-based wear-resistant thick coating on the surface of the cotton picking spindle body 1 is greater than 40N (measured by the scratch method), the microhardness of the Si-rich carbon-based wear-resistant thick coating is 1200-1600HV, and the dry friction coefficient between the Si-rich carbon-based wear-resistant thick coating and the Si3N4 ball is less than 0.2.

[0048] In the present invention, no additional heat source is required in the coating preparation process, and the deposition temperature can be controlled within 200° C. Plasma discharges in the mesh cage, and heat is generated during the coating deposition process, which can heat the pick ingots in the mesh cage to above 100° C. The temperature in the mesh cage can be controlled by adjusting the voltage, current and gas flow of the pulse power supply to avoid excessively high deposition temperature.

[0049] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for preparing a cotton picking spindle, characterized in that: The cotton picking spindle comprises a cotton picking spindle body, the upper end of the cotton picking spindle body is provided with hook teeth, the surface of the cotton picking spindle body is provided with a Si-rich carbon-based wear-resistant thick coating, the Si-rich carbon-based wear-resistant thick coating comprises a Si transition layer and a cotton picking spindle working layer, the Si transition layer is arranged between the surface of the cotton picking spindle body and the cotton picking spindle working layer, and the cotton picking spindle working layer comprises multiple layers of Si-rich doped carbon-based coatings and pure carbon-based coatings arranged alternately; The preparation method comprises the following steps: 1) Flexible sandblasting of cotton picking spindles: The cotton picking spindles are pre-treated by flexible wet sandblasting; when sandblasting, the spindles are placed in the sandblasting machine for sandblasting; 2) Pre-cleaning of cotton picking spindles: put the sandblasted cotton picking spindles into an ultrasonic cleaning tank, fix the bottom on a rotating seat, and the cleaning tank contains a degreasing cleaning agent. Turn on the ultrasonic generator during cleaning, and the cleaning brush and cotton picking spindles can rotate. The surface pollutants and residual sand particles are removed by ultrasonic vibration and brushes. Use compressed air to blow dry the cotton picking spindles after cleaning, and put them into a heat preservation oven for drying; 3) Cotton picking ingots are loaded into the furnace: the cleaned and dried cotton picking ingots are hung with their tips facing downwards in a metal frame, with a distance of more than 2cm between the ingots. A 80-200 mesh molybdenum wire mesh is used to wrap the outside of the frame to form a metal grid cage. The metal grid cage is connected to the negative pole of the pulse power supply with a wire and is insulated from the vacuum chamber; the positive pole of the pulse power supply is connected to the side wall of the vacuum chamber; 4) Ion bombardment cleaning of cotton picking finger surface: vacuum chamber is evacuated to 3X10 -3 After Pa, inert gas is introduced with a gas flow rate of 50-500sccm, and the pulse power supply is turned on with a voltage of 500-2000V, a current of 20-80A, and a frequency of 200-600Hz for 10-60min; 5) Preparation of transition layer for cotton picking: adjust the argon flow rate to 100-500sccm, introduce silane gas, the gas flow rate is 5-50sccm, the pulse power supply voltage is adjusted to 800-1500V, the current is 40-80A, the frequency is 200-400Hz, and it lasts for 10-25min; 6) Preparation of cotton picking spindle working layer: adjust the argon flow rate to 50-300sccm, keep the silane gas flow rate unchanged, introduce acetylene gas, the acetylene gas flow rate is 50-200sccm, adjust the pulse power supply voltage to 1000-1500V, the current is 20-100A, the frequency is 300-600Hz, and continue for 10-20min to prepare Si-rich doped carbon-based coating; turn off the silane gas, keep other conditions unchanged, and continue for 10-20min to prepare pure carbon-based coating; Si-rich doped carbon-based coating and pure carbon-based coating are alternately deposited; 7) The cotton picking spindles are taken out of the furnace: After the coating deposition is completed, the cotton picking spindles are cooled in the vacuum chamber along with the furnace. When the vacuum chamber temperature is lower than 50°C, the vacuum chamber door is opened and the cotton picking spindles are taken out.

2. The method for preparing a cotton picking spindle according to claim 1, characterized in that: In step 1), the sand material is 80-200 mesh flexible polymer sand, and the sandblasting pressure is 0.3-0.6MPa; the spray gun in the sandblasting machine is 5-30cm away from the picking ingot for sandblasting, and the spray sand flow is cleaned along the direction of the hook tooth gap, and each picking ingot is cleaned for 10-90 seconds.

3. The method for preparing a cotton picking spindle according to claim 1, characterized in that: In step 3), the cotton picking spindles are suspended in a metal frame by spindle fixing wires, and the metal frame is cylindrical.

4. The method for preparing a cotton picking spindle according to claim 1, characterized in that: The bonding strength of the Si-rich carbon-based wear-resistant thick coating on the surface of the cotton picking spindle body is greater than 40N, the microhardness of the Si-rich carbon-based wear-resistant thick coating is 1200-1600HV, and the dry friction coefficient between the Si-rich carbon-based wear-resistant thick coating and the Si3N4 ball is less than 0.

2.

5. The method for preparing a cotton picking spindle according to claim 1, characterized in that: The thickness of the Si transition layer is 2-3 μm.

6. The method for preparing a cotton picking spindle according to claim 1, characterized in that: The total thickness of the Si-rich doped carbon-based coating and the pure carbon-based coating is 8-12 μm.

7. The method for preparing a cotton picking spindle according to claim 1, characterized in that: The Si-rich doped carbon-based coating and the pure carbon-based coating are each provided with 4-6 layers.

Images