RV speed reducer lubricating grease

Abstract

The invention relates to the technical field of lubricating grease, in particular to RV speed reducer lubricating grease. The RV speed reducer lubricating grease prepared by the invention has excellent low friction coefficient, high conduction efficiency, low running temperature rise, load resistance, low-temperature fluidity, startability, shear resistance and protective property. The RV speed reducer lubricating grease plays a crucial role in the service life of grease and the lubrication protection of all transmission parts in a speed reducer, provides a powerful guarantee for prolonging the service life of the RV speed reducer, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating grease, and in particular to a lubricating grease for an RV reducer. Background Art

[0002] As a core component of industrial robots, RV reducers are interdependent and mutually reinforcing. RV reducers offer a wide range of transmission ratios, relatively stable accuracy, high fatigue strength, and enhanced rigidity and torque-carrying capacity. They are generally used in heavy-load applications such as robot arms and bases. However, their heavy weight and large dimensions prevent them from being developed for lightweight and flexible applications. Furthermore, their complex structure and high cost prevent them from being developed for light-load applications.

[0003] The RV reducer's structure consists of three main parts: 1. Input section: The input shaft is connected to the motor, and the input gear is mounted on the input shaft, transmitting the motor's power to the reducer. The input gear drives the meshing spur gear, performing the first stage of speed reduction. 2. Intermediate transmission section: The spur gear is connected to the crankshaft, and the eccentric portion of the crankshaft is equipped with the RV gear, or cycloid, via a rolling bearing. Pin teeth are mounted on the inside of the housing, one more than the number of teeth on the cycloid. When the crankshaft rotates, the cycloid engages with the pin teeth due to eccentric motion, achieving the second stage of speed reduction. 3. Output section: The output mechanism is the planetary carrier. The cycloid's self-rotation is transmitted to the planetary carrier via the crankshaft support bearings on the planetary carrier. The large rigid disc on the left end of the planetary carrier is bolted to the working structure to output the reduced power.

[0004] Lubrication points of RV reducer: 1. Gear meshing: including the meshing parts of the input gear and the spur gear, and the meshing parts of the cycloid wheel and the pin teeth. At these positions, the tooth surfaces slide and roll relative to each other, and good lubrication is required to reduce wear, reduce friction power consumption and noise, and ensure the accuracy of transmission efficiency. 2. Bearing parts: The rolling bearings between the crankshaft and the cycloid wheel, as well as the bearings supporting the input shaft, planetary carrier, etc., need lubrication. Lubrication can reduce the friction coefficient of the bearings, reduce heat and increase the service life of the bearings, and ensure that the rotation of each shaft is flexible and smooth. 3. Between the pin teeth and the pin gear housing: there is relative sliding, which is prone to wear. Lubrication is required to improve friction conditions, increase load-bearing capacity, and extend the service life of components. 4. Shaft and sleeve mating: The mating parts such as the input shaft and sleeve, the crankshaft and sleeve, etc. will also have relative movement during operation, and lubrication is required to reduce wear and prevent seizure.

[0005] The performance requirements of RV reducer for grease are as follows: 1. The grease has excellent anti-stripping performance on the friction pair of the RV reducer, and can have excellent lubricity under sliding and rolling friction motion modes, preventing noise caused by vibration; 2. The low friction coefficient of the grease. The lower friction coefficient can greatly improve the transmission efficiency during the operation of the components, reduce the temperature generated during the friction process and shorten the service life; 3. The load resistance of the grease. The grease is required to have a higher load resistance at the joint between the shaft and the sleeve to prevent wear and seizure of the moving parts; 4. The low-temperature fluidity and starting performance of the grease. When the RV reducer is started in a low-temperature environment, if the grease has poor fluidity, dry friction will occur in the parts without grease, causing wear; at the same time, the grease additives in the low-temperature environment have not reached the effective temperature. At this time, the base oil and soap fiber in the grease are required to play an initial lubrication role, and the grease is required to have a certain low-temperature fluidity; 5. The grease has excellent shear resistance to prevent the loss of grease after shearing.

[0006] CN117106506A discloses a composite barium-based grease for RV reducers and a preparation method thereof, but there is still room for improvement in terms of low-temperature starting performance and the like. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention provides an RV reducer grease, comprising: a mixed base oil, a thickener, a friction modifier, an extreme pressure anti-wear agent, a metal deactivator, an antioxidant and a rust inhibitor; The viscosity of the mixed base oil at 40°C is 60-70 mm 2 / s, viscosity index is above 110, pour point is not higher than -35℃; The friction modifier is an organic molybdenum compound and / or an organic borate compound; The extreme pressure anti-wear agent is zinc dialkyl dithiophosphate and / or zinc dialkyl dithiocarbamate; The metal deactivator is at least one of a toluenetriazole derivative, a 2,5-dimercapto-1,3,4-thiadiazole derivative, and a sulfur-nitrogen heterocyclic compound.

[0008] Through extensive research into compounding combinations of base oils, friction modifiers, extreme pressure anti-wear agents, and metal deactivators, the present invention has discovered that greases formulated with these ingredients can meet the requirements of RV reducers. The compounded additive system of friction modifiers, extreme pressure anti-wear agents, and metal deactivators employed in the present invention exhibits a very low coefficient of friction in both point-to-surface and face-to-face friction modes, effectively mitigating the risks of high temperatures.

[0009] Preferably, the organic molybdenum compound is at least one of di-n-butyldithiocarbamate molybdenum, di-n-butyldithiophosphate molybdenum, and an organic molybdenum complex; And / or, the organic borate compound is a partially borated product of a mixture of acyldiethanolamine and monoglyceride.

[0010] Preferably, the organic boronic acid ester compound is an inactive boronic acid ester.

[0011] Preferably, the friction modifier is a mixture of molybdenum di-n-butyldithiocarbamate and an organic molybdenum complex; the extreme pressure anti-wear agent is zinc dialkyldithiocarbamate; and the metal deactivator is a tolutriazole derivative. Alternatively, the friction modifier is a compound of molybdenum di-n-butyldithiocarbamate and an organic borate; the extreme pressure anti-wear agent is zinc dialkyldithiophosphate; and the metal deactivator is a 2,5-dimercapto-1,3,4-thiadiazole derivative; Alternatively, the friction modifier is a mixture of di-n-butyl molybdenum dithiophosphate, an organic molybdenum complex and an organic borate compound; the extreme pressure anti-wear agent is zinc dialkyl dithiocarbamate; and the metal deactivator is a sulfur-nitrogen heterocyclic compound.

[0012] More preferably, when the friction modifier is a mixture of molybdenum di-n-butyldithiocarbamate and an organic molybdenum complex, the extreme pressure anti-wear agent is zinc dialkyldithiocarbamate, and the metal deactivator is a tolyltriazole derivative, the weight ratio of molybdenum di-n-butyldithiocarbamate, the organic molybdenum complex, zinc dialkyldithiocarbamate and the tolyltriazole derivative is (2.5-3.5):1:(1.5-2.5):(0.3-0.5).

[0013] More preferably, when the friction modifier is molybdenum di-n-butyldithiocarbamate and an organic borate compound, the extreme pressure anti-wear agent is zinc dialkyldithiophosphate, and the metal deactivator is a 2,5-dimercapto-1,3,4-thiadiazole derivative, the weight ratio of molybdenum di-n-butyldithiocarbamate, the organic borate compound, zinc dialkyldithiophosphate and the 2,5-dimercapto-1,3,4-thiadiazole derivative is (1.5-2.5): (0.4-0.6): (1.4-1.6): (0.25-0.35).

[0014] More preferably, when the friction modifier is a mixture of di-n-butyl molybdenum dithiophosphate, an organic molybdenum complex and an organic borate compound, the extreme pressure anti-wear agent is zinc dialkyl dithiocarbamate, and the metal deactivator is a sulfur-nitrogen heterocyclic compound, the weight ratio of di-n-butyl molybdenum dithiophosphate, the organic molybdenum complex, the organic borate compound, the zinc dialkyl dithiocarbamate and the sulfur-nitrogen heterocyclic compound is (2-3):(0.4-0.6):(0.4-0.6):1:(0.3-0.5).

[0015] Under the above types and ratios, grease has better friction coefficient and transmission efficiency.

[0016] Preferably, the mixed base oil is a mixture of polyalphaolefin, deeply hydrogenated mineral oil and ester oil.

[0017] More preferably, the polyalphaolefin is PAO6 or INEOS 166, the deeply hydrogenated mineral oil is HVI Ic, and the ester oil is dipentaerythritol ester.

[0018] More preferably, the mixed base oil is a mixture of polyalphaolefin, deeply hydrogenated mineral oil and ester oil in a weight ratio of (3-4): (5-6): 1.

[0019] When the above base oil types are selected for compounding, the grease has excellent low-temperature fluidity and low-temperature lubrication properties.

[0020] Among them, the viscosity of polya olefin at 40℃ is 30 mm 2 / s, viscosity index 132, pour point -60℃; deeply hydrogenated mineral oil is HVI Ic 500SN (Erickson Mobil), with a viscosity of 94 mm at 40℃ 2 / s, viscosity index 100, pour point -15℃; the viscosity of dipentaerythritol ester at 40℃ is 160-180mm 2 / s, viscosity index 110, pour point -35℃.

[0021] Preferably, the thickener is lithium polyurea; in the lithium polyurea, the urea group is prepared from dodecylamine and 4,4-diphenylmethane diisocyanate, and the lithium soap group is prepared from 12-hydroxystearic acid and lithium hydroxide solution (the lithium polyurea can be selected from Shandong Red Star lithium polyurea soap powder).

[0022] Urea groups exhibit excellent adsorption and spalling resistance on metal friction surfaces, and polyurea-lithium thickeners exhibit excellent spalling resistance in the grease system of this invention. Furthermore, polyurea-lithium thickeners exhibit better shear resistance than lithium thickeners, reducing the risk of grease loss under long-term shear stress.

[0023] Preferably, the antioxidant is N-phenyl-a-naphthylamine.

[0024] Preferably, the rust inhibitor is refined zinc naphthenate.

[0025] Preferably, the grease comprises the following components in parts by weight: 93-95 parts of mixed base oil, 5-7 parts of thickener, 2-4 parts of friction modifier, 1-2 parts of extreme pressure anti-wear agent, 0.2-0.4 parts of metal deactivator, 0.5-1 parts of antioxidant and 0.5-1 parts of rust inhibitor.

[0026] More preferably, the grease comprises the following components in parts by weight: 93-95 parts of mixed base oil, 5-7 parts of thickener, 2-4 parts of friction modifier, 1-2 parts of extreme pressure anti-wear agent, 0.2-0.4 parts of metal deactivator, 0.5-1 parts of antioxidant and 0.5-1 parts of rust inhibitor; The mixed base oil is a mixture of PAO6, HVI Ic 500SN and dipentaerythritol ester; The thickener is lithium polyurea, wherein the urea group is prepared from dodecylamine and 4,4-diphenylmethane diisocyanate, and the lithium soap group is prepared from 12-hydroxystearic acid and lithium hydroxide solution; The friction modifier is a mixture of molybdenum di-n-butyldithiocarbamate and an organic molybdenum complex in a weight ratio of (2-4):1; The extreme pressure anti-wear agent is zinc dialkyl dithiocarbamate; The metal deactivator is a tolutriazole derivative; The antioxidant is N-phenyl-a-naphthylamine; The rust inhibitor is refined zinc naphthenate.

[0027] Compared with the prior art, the present invention has the following beneficial effects: The present invention prepares a RV reducer grease with excellent low friction coefficient, high transmission efficiency, low operating temperature rise, load resistance, low-temperature fluidity and start-up performance, shear resistance, and protective properties. The RV reducer grease of the present invention plays a crucial role in extending the service life of the grease and lubricating and protecting the various transmission components in the reducer, providing a strong guarantee for extending the service life of RV reducers and having broad application prospects. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be described clearly and completely below. Obviously, the embodiments described are 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. In the embodiments provided in this specification, if no specific technology or conditions are specified, the technology or conditions described in the literature in this field or the product instructions shall be followed. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased through regular channels. The parts in the following embodiments represent parts by weight. The viscosity of PAO6 (Erickson Mobil) in the following embodiments is 30 mm at 40°C. 2 / s, viscosity index 132, pour point -60℃; HVI Ic 500SN (Erickson Mobil), its viscosity at 40℃ is 94 mm 2 / s, viscosity index 100, pour point -15℃; dipentaerythritol ester, its viscosity at 40℃ is 160-180mm 2 / s, viscosity index 110, pour point -35℃.

[0029] The mixed base oil of the following embodiment is a mixture of poly alpha olefin-PAO6, deep hydrogenated mineral oil-HVI Ic 500SN and ester oil-dipentaerythritol ester in a weight ratio of 4:5:1; its viscosity at 40°C is 62 mm 2 / s, viscosity index is 110, pour point is -36℃.

[0030] The thickening agent in the following examples is polyurea lithium (Shandong Hongxing polyurea lithium soap powder), wherein the urea group is prepared from dodecylamine and 4,4-diphenylmethane diisocyanate, and the lithium soap group is prepared from 12-hydroxystearic acid and lithium hydroxide solution.

[0031] The organic molybdenum complex in the following examples is Vanderbilt V855.

[0032] The borate ester in the following examples is Vanderbilt V289.

[0033] The sulfur-nitrogen heterocyclic compound in the following examples is Vanderbilt V601.

[0034] The tolyltriazole derivative in the following examples is IRGAMET 39 from BASF.

[0035] Example 1 This embodiment provides an RV reducer grease, comprising the following components in parts by weight: Mix 94 parts of base oil, 6 parts of thickener, 2.5 parts of friction modifier, 1.5 parts of extreme pressure anti-wear agent, 0.3 parts of metal deactivator, 1 part of antioxidant and 0.5 parts of rust inhibitor; The friction modifier is a mixture of 2 parts of di-n-butyldithiocarbamate molybdenum and 0.5 parts of borate; The extreme pressure anti-wear agent is zinc dialkyl dithiophosphate; The metal deactivator is a 2,5-dimercapto-1,3,4-thiadiazole derivative; The antioxidant is N-phenyl-a-naphthylamine.

[0036] The rust inhibitor is refined zinc naphthenate.

[0037] The preparation method of the RV reducer grease of this embodiment is as follows: After mixing 2 / 3 of the base oil and thickener soap powder in proportion, heating to 198°C, adding the remaining 1 / 3 of the base oil, and when the temperature drops to 80°C, adding friction modifier, extreme pressure anti-wear agent, metal deactivator, antioxidant and rust inhibitor, mixing evenly, and then dispersing through a three-roll mill or homogenizer to obtain the product.

[0038] Example 2 This embodiment provides an RV reducer grease, comprising the following components in parts by weight: Mix 94 parts of base oil, 6 parts of thickener, 3.5 parts of friction modifier, 1 part of extreme pressure anti-wear agent, 0.4 parts of metal deactivator, 1 part of antioxidant and 0.5 parts of rust inhibitor; The friction modifier is a mixture of 2.5 parts of di-n-butyl molybdenum dithiophosphate, 0.5 parts of an organic molybdenum complex, and 0.5 parts of a borate ester; The extreme pressure anti-wear agent is zinc dialkyldithiocarbamate; The metal deactivator is a sulfur-nitrogen heterocyclic compound; The antioxidant is N-phenyl-a-naphthylamine.

[0039] The rust inhibitor is refined zinc naphthenate.

[0040] The preparation method is the same as that of Example 1.

[0041] Example 3 This embodiment provides an RV reducer grease, comprising the following components in parts by weight: Mix 94 parts of base oil, 6 parts of thickener, 4 parts of friction modifier, 2 parts of extreme pressure anti-wear agent, 0.4 parts of metal deactivator, 1 part of antioxidant and 0.5 parts of rust inhibitor; The friction modifier is a mixture of 3 parts of molybdenum di-n-butyldithiocarbamate and 1 part of an organic molybdenum complex; The extreme pressure anti-wear agent is zinc dialkyldithiocarbamate; The metal deactivator is a tolutriazole derivative; The antioxidant is N-phenyl-a-naphthylamine.

[0042] The rust inhibitor is refined zinc naphthenate.

[0043] The preparation method is the same as that of Example 1.

[0044] Comparative Example 1 Commercially available Nabtesco RE0# grease.

[0045] Comparative Example 2 This comparative example provides a RV reducer grease, which differs from Example 3 only in that: The blended base oil is a mixture of polyalphaolefin (PAO6), deeply hydrogenated mineral oil (HVI Ic 500SN), and diester (ester oil) in a weight ratio of 4:5:1. The blended base oil has a viscosity of 43 at 40°C and a viscosity index of 106.

[0046] Comparative Example 3 This comparative example provides an RV reducer grease, which differs from Example 3 only in that the friction modifier is a mixture of 3 parts of alkyl triphenyl thiophosphate and 1 part of an organic molybdenum complex.

[0047] Comparative Example 4 This comparative example provides an RV reducer grease, which is different from Example 3 only in that the extreme pressure anti-wear agent is replaced by an equal amount of tricresyl phosphate.

[0048] Comparative Example 5 This comparative example provides an RV reducer grease, which differs from Example 3 only in that the metal deactivator is replaced by an equal amount of azetidinedioic anhydride.

[0049] Test Example 1 The lubricating greases of the above examples and comparative examples were compared in terms of low friction coefficient, load resistance, low temperature starting performance, shear resistance, and oxidation resistance. The specific evaluation method is as follows: 1. Low coefficient of friction is assessed by the grease high frequency linear vibration test (SRV) (ASTM D5706); 2. Load resistance is assessed by testing the grease PB, PD (ASTM D2266) and Timken OK value (ASTM D2509); 3. Antioxidant properties are assessed by oxidation induction period (PDSC test method SH / T 0790); 4. Low temperature starting performance is evaluated by the low temperature torque test of ball bearing grease (ASTM D1478); 5. Shear resistance is evaluated by 100,000 shear cycles (ASTM D217) and roller (ASTM D1831).

[0050] The specific test data are shown in Table 1 below.

[0051] Table 1 Grease properties

[0052] It can be concluded from Table 1 that the grease of the embodiment of the present invention exhibits excellent performance in terms of low friction coefficient, load resistance, low temperature starting performance, shear resistance, and oxidation resistance, and has been verified for a long time on actual industrial robots.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An RV reducer grease, characterized in that: include: Mixed base oil, thickener, friction modifier, extreme pressure anti-wear agent, metal deactivator, antioxidant and rust inhibitor; The viscosity of the mixed base oil at 40°C is 60-70 mm 2 / s, viscosity index is above 110, pour point is not higher than -35℃; The friction modifier is an organic molybdenum compound and / or an organic borate compound; The extreme pressure anti-wear agent is zinc dialkyl dithiophosphate and / or zinc dialkyl dithiocarbamate; The metal deactivator is at least one of a toluenetriazole derivative, a 2,5-dimercapto-1,3,4-thiadiazole derivative, and a sulfur-nitrogen heterocyclic compound.

2. The lubricating grease according to claim 1, characterized in that The organic molybdenum compound is at least one of di-n-butyldithiocarbamate molybdenum, di-n-butyldithiophosphate molybdenum, and an organic molybdenum complex; And / or, the organic borate compound is a partially borated product of a mixture of acyldiethanolamine and monoglyceride.

3. The lubricating grease according to claim 1, wherein The friction modifier is a mixture of molybdenum di-n-butyldithiocarbamate and an organic molybdenum complex; the extreme pressure anti-wear agent is zinc dialkyldithiocarbamate; and the metal deactivator is a tolutriazole derivative. Alternatively, the friction modifier is a compound of molybdenum di-n-butyldithiocarbamate and an organic borate; the extreme pressure anti-wear agent is zinc dialkyldithiophosphate; and the metal deactivator is a 2,5-dimercapto-1,3,4-thiadiazole derivative; Alternatively, the friction modifier is a mixture of di-n-butyl molybdenum dithiophosphate, an organic molybdenum complex and an organic borate compound; the extreme pressure anti-wear agent is zinc dialkyl dithiocarbamate; and the metal deactivator is a sulfur-nitrogen heterocyclic compound.

4. The lubricating grease according to claim 1, wherein The mixed base oil is formed by mixing polyalphaolefin, deeply hydrogenated mineral oil and ester oil.

5. The lubricating grease according to claim 4, characterized in that The polyalphaolefin is PAO6 or INEOS 166, the deeply hydrogenated mineral oil is HVI Ic, and the ester oil is dipentaerythritol ester.

6. The lubricating grease according to claim 1, wherein The thickener is lithium polyurea; in the lithium polyurea, the urea group is prepared from dodecylamine and 4,4-diphenylmethane diisocyanate, and the lithium soap group is prepared from 12-hydroxystearic acid and lithium hydroxide solution.

7. The lubricating grease according to claim 1, wherein The antioxidant is N-phenyl-a-naphthylamine.

8. The lubricating grease according to claim 1, wherein The rust inhibitor is refined zinc naphthenate.

9. The lubricating grease according to any one of claims 1 to 8, characterized in that The invention comprises the following components in parts by weight: 93-95 parts of mixed base oil, 5-7 parts of thickener, 2-4 parts of friction modifier, 1-2 parts of extreme pressure anti-wear agent, 0.2-0.4 parts of metal deactivator, 0.5-1 parts of antioxidant and 0.5-1 parts of rust inhibitor.

10. The lubricating grease according to claim 9, characterized in that The invention comprises the following components in parts by weight: 93-95 parts of mixed base oil, 5-7 parts of thickener, 2-4 parts of friction modifier, 1-2 parts of extreme pressure anti-wear agent, 0.2-0.4 parts of metal deactivator, 0.5-1 parts of antioxidant and 0.5-1 parts of rust inhibitor; The mixed base oil is a mixture of PAO6, HVI Ic 500SN and dipentaerythritol ester; The thickener is lithium polyurea, wherein the urea group is prepared from dodecylamine and 4,4-diphenylmethane diisocyanate, and the lithium soap group is prepared from 12-hydroxystearic acid and lithium hydroxide solution; The friction modifier is a mixture of molybdenum di-n-butyldithiocarbamate and an organic molybdenum complex in a weight ratio of (2-4):1; The extreme pressure anti-wear agent is zinc dialkyl dithiocarbamate; The metal deactivator is a tolutriazole derivative; The antioxidant is N-phenyl-a-naphthylamine; The rust inhibitor is refined zinc naphthenate.

Images