A sliding bearing having an oil storage porous structure

Abstract

A sliding bearing with oil storage porous structure, comprising a bearing and at least one oil storage capsule arranged on the bearing. The oil storage capsule is a porous sintered copper alloy part and has a plurality of pores, V is the total volume of the oil storage capsule, v is the clearance volume between the bearing and the counter bearing, the total volume of the oil storage capsule should satisfy the formula: V*((1+α) 3 -1)*(80-60)>v, wherein α is the linear expansion coefficient of the copper alloy, and the porosity of the oil storage capsule is less than 40% of the total volume of the oil storage capsule. The sliding bearing is characterized in that a receiving cavity is formed on the working surface of the bearing, and the oil storage capsule made of the porous sintered copper alloy is arranged in the receiving cavity. The lubricating oil overflowing from the oil storage capsule can still fill the gap between the bearing and the counter bearing, thereby preventing the bearing from being damaged or locked in a short time in the case of sudden start or stop, and further avoiding damage to the entire equipment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sliding bearing, in particular to a sliding bearing with oil storage porous structure and its blank. BACKGROUND

[0002] Wind power generation is gradually large-scale, and the diameter of the bearing used in the wind power gearbox is also getting larger and larger, so in order to reduce the cost and solve the manufacturing technology of large rolling bearing, it is a trend to replace rolling with sliding. Sliding bearing not only can reduce the volume of the gearbox, but also can improve the power density. The sliding bearing of the wind power gearbox belongs to the typical fluid lubrication, that is, the oil is supplied from the outside and then flows out from the oil inlet hole of the pin shaft end and the oil outlet hole on the working surface. Under normal working condition, the sliding bearing and the gear inner ring form a sliding surface, and under the dynamic pressure state of the lubricating oil, the sliding bearing and the gear inner ring are isolated to form an oil film, thereby playing a lubricating role.

[0003] However, due to the complex working condition of wind power, the start-stop working condition often occurs, or the oil inlet hole is blocked by the phenomenon of abrasive, so under these conditions, the oil may be cut off, that is, the oil film for lubrication is lacking between the sliding bearing and the gear. It can be understood that once the oil is cut off, the sliding bearing will directly contact the gear inner ring, resulting in dry friction or boundary friction. At the same time, since the sliding bearing is generally made of copper alloy, under the condition of dry friction, the working surface will be severely deteriorated, that is, the copper surface will be worn, resulting in a sharp rise in temperature, so that the copper alloy expands, and further reduces the fitting clearance between the sliding bearing and the gear, thereby causing the shaft to burn or lock in a short time, which is not enough to wait for the switching of the start-stop working condition, or the blocked oil hole is again opened by the oil pressure. SUMMARY

[0004] Therefore, the present application provides a sliding bearing with oil storage porous structure and its blank which can adapt to high-precision impact resistance requirements to solve the above problems.

[0005] A sliding bearing with oil storage porous structure, comprising a bearing and at least one oil storage capsule arranged on the bearing. The oil storage capsule is a porous sintered copper alloy part and has a plurality of pores, and V is the total volume of the oil storage capsule, and v is the gap volume between the counterpart and the bearing 10, then the total volume of the oil storage capsule should meet the following formula:

[0006] V*((1+α) 3 -1)*(80-60)>v

[0007] Wherein, α is the linear expansion coefficient of the copper alloy, 60 is the temperature of the oil storage capsule in normal working condition, 80 is the temperature of the oil storage capsule in abnormal condition; and the porosity of the oil storage capsule is less than 40% of the total volume of the oil storage capsule.

[0008] Further, the bearing comprises a bearing body, a plurality of oil channels arranged on the bearing body, and a plurality of pairs of first oil outlet holes and first oil return holes arranged on the oil channels.

[0009] Further, the bearing further comprises a plurality of pairs of second oil outlet holes and second oil return holes arranged on the working surface of the bearing body, and a plurality of accommodation cavities arranged at the oil outlets of the second oil outlet holes, and the oil storage capsule is arranged in the accommodation cavities.

[0010] Further, the free surface of the oil storage capsule is the working surface.

[0011] Further, the calculation method of the gap volume between the pair of grinding elements and the bearing is as follows:

[0012] Assuming that the diameter of the bearing is d, the axial height is h, and the fitting gap between the bearing and the pair of grinding elements is 1-2‰, then the diameter of the inner ring of the pair of grinding elements D = d*(1+1‰)~d*(1+2‰), and the gap volume v between the pair of grinding elements and the bearing is 0.25*π(D*D-d*d)*h.

[0013] Further, the porous sintered copper alloy part is sintered from copper alloy and pore-forming agent, and the pore-forming agent is burned off during sintering to form the porous sintered copper alloy part.

[0014] Further, the volume ratio of the pore-forming agent to the total volume of the copper alloy and graphite before sintering is A, and V*A should be greater than or equal to v.

[0015] Further, the pore-forming agent is graphite.

[0016] Further, (1+α) 3 -1 is the volume expansion coefficient of the copper alloy within 25-100℃.

[0017] Compared with the prior art, the sliding bearing with a porous oil-storing structure provided by the present invention has a cavity on the working surface of the bearing, and an oil-storing capsule made of porous sintered copper alloy is placed in the cavity. Since the volume change of the pores in the oil-storing capsule 20 after temperature change should be greater than v, i.e., V*((1+α)³-1)*(80-60) should be greater than v, the lubricating oil overflowing from the oil-storing capsule can still fill the gap between the bearing and the mating parts when the oil temperature between the bearing and the mating parts changes from 60 degrees to 80 degrees. This prevents the bearing from being damaged or seized in a short time under conditions such as sudden start-up, sudden stop, or accidental oil cut-off, thus avoiding damage to the entire equipment. At the same time, the porosity V*A in the oil-storing capsule should be less than 40% of the total volume of the oil-storing capsule, ensuring that the mechanical strength of the oil-storing capsule can still guarantee its normal operation. The bearing will not be unable to withstand high-intensity friction due to insufficient mechanical strength, thus preventing a decrease in bearing quality. Attached Figure Description

[0018] Figure 1 This invention provides a schematic diagram of a sliding bearing with an oil-storing porous structure.

[0019] Figure 2 for Figure 1 An exploded view of a sliding bearing with a porous oil storage structure. Detailed Implementation

[0020] The following provides a more detailed description of specific embodiments of the present invention. It should be understood that the description of the embodiments of the present invention herein is not intended to limit the scope of protection of the present invention.

[0021] like Figure 1 and Figure 2 The diagram shows a schematic representation of a sliding bearing with a porous oil-storage structure provided by the present invention. The sliding bearing with the porous oil-storage structure includes a bearing 10 and at least one oil-storage capsule 20 disposed on the bearing 10. It is conceivable that the sliding bearing with the porous oil-storage structure also includes other functional modules, such as mounting structures, etc., which are techniques well known to those skilled in the art and will not be described in detail here.

[0022] The bearing 10 comprises a bearing body 11, a plurality of oil channels 12 arranged on the bearing body 11, a plurality of pairs of first oil outlet holes 13 and first oil return holes 14 arranged on the oil channels 12, a plurality of pairs of second oil outlet holes 15 and second oil return holes 16 arranged on the working surface of the bearing body 11, and a plurality of accommodating cavities 17 arranged at the oil outlet of the second oil outlet holes 15. The bearing body 11 can be cylindrical and can be made of copper alloy. It can be understood that, in order to reduce the cost, the bearing body 11 can be a composite material bearing formed by sintering or laser cladding a layer of copper alloy on a stainless steel substrate. In addition, the specification parameters of the bearing body 11 can be designed according to the actual use occasion, which will not be described here. The oil channels 12 are also arranged on the radial side wall of the bearing body 11. Generally, the oil channels 12 are arranged on the side wall of the bearing body 11 to form a plurality of oil storage grooves. The structures of the first oil outlet holes 13 and the first oil return holes 14 and the second oil outlet holes 15 and the second oil return holes 16 are the same, and the only difference is the different positions. Only the first oil outlet holes 13 and the first oil return holes 14 will be described below.

[0023] The first oil outlet hole 13 and the first oil return hole 14 are usually arranged in pairs on the radial side wall of the bearing body 11. The first oil outlet hole 13 provides lubricating oil between the bearing body 11 and the counter element such as a gear or a bearing seat under the pressure of an external oil supply device. The first oil return hole 14 allows the lubricating oil to return to the external oil supply device, thereby forming a cycle to achieve sufficient lubrication of the bearing body 11 and the counter element. However, during use of the bearing 10, the external oil supply device may also have sudden stop or sudden start conditions. In the case of sudden stop or sudden start, the first oil outlet hole 13 often does not have oil coming out. Another situation is that during long-term use of the bearing 10, the bearing 10 and the counter element will form abrasive dust, which will block one or more of the first oil outlet holes 13, thereby causing the oil outlet hole to not have oil coming out. When the second oil outlet hole 15 opened on the working surface does not have oil coming out, the working surface condition will deteriorate sharply, i.e. the copper surface will wear out, causing the temperature to rise sharply, thereby causing the copper alloy to expand, and further causing the sliding bearing and the counter element to have a reduced fit clearance, which will cause the shaft to burn or seize in a short time. Obviously, this is not allowed, because burning the shaft will damage the bearing, and seizure will not be able to start again, and can only be started after complete cooling, at which time the bearing may have been damaged. The accommodating cavity 17 is opened on the working surface of the bearing 10, i.e. on the radial side wall of the bearing 10. The shape of the accommodating cavity 17 can be quadrilateral, circular, or any other shape. At the same time, the depth of the accommodating cavity 17 can be set according to actual needs. The accommodating cavity 17 coincides with the oil outlet hole of the second oil outlet hole 15, i.e. the accommodating cavity 17 is located on the oil outlet hole of the second oil outlet hole 15. The accommodating cavity 17 is used to set the oil storage capsule 20.

[0024] The oil storage capsule 20 is arranged in the accommodating cavity 17, and the arrangement method can be welding, sintering, or mechanical embedding such as tight fitting, etc., which will not be described here. The free surface of the oil storage capsule 20 is also a working surface, so it can be made of copper alloy, and the oil storage capsule 20 is a porous sintered copper alloy to achieve oil containing. The porosity of the porous sintered copper alloy is a very important parameter, because when the second oil outlet hole 15 opened on the working surface does not have oil coming out, the working surface condition deteriorates sharply, causing the temperature to rise sharply. The temperature rise causes the porous sintered copper alloy to expand. When the porous sintered copper alloy expands, it will squeeze out the oil contained in the pores. The squeezed-out oil can lubricate the bearing 10 and the counter element in a short time, avoiding the phenomenon of burning the shaft or seizure of the bearing 10 and the counter element in a short time due to the second oil outlet hole 15 not having oil coming out, which causes accidents.

[0025] Meanwhile, the porosity cannot be too large, because too large porosity will result in the oil storage capacity of the porous sintered copper alloy being reduced, i.e. the oil storage capsule 20 has many pores, but these pores are not filled with oil, and meanwhile, due to too many pores, the mechanical strength of the oil storage capsule 20 is reduced, and cannot meet the mechanical strength requirement of the bearing 10.

[0026] The method for preparing the porous sintered copper alloy is as follows:

[0027] STEP101: Provide copper alloy powder and pore-forming agent, and first mix the copper alloy powder and pore-forming agent in a mixer according to a certain proportion to make them uniform;

[0028] STEP102: Perform green body preparation on the mixed material by means of powder sintering;

[0029] STEP103: Put the green body material into a reducing atmosphere to perform sintering, and obtain a precursor;

[0030] STEP104: Put the precursor into an oxygen atmosphere to perform decarburization sintering, and make the pore-forming agent form gas escape, and obtain the porous sintered copper alloy.

[0031] In the step STEP101, the proportioning of the copper alloy powder and the pore-forming agent will determine the pore volume of the porous sintered copper alloy, and the calculation steps are as follows:

[0032] STEP201: Assuming that the diameter of the bearing 10 is d, the axial height is h, and the fitting clearance between the bearing 10 and the matching part is generally 1-2‰, then the diameter D of the inner ring of the matching part is d*(1+1‰)-d*(1+2‰), and the clearance volume v between the matching part and the bearing 10 is 0.25*π(D*D-d*d)*h;

[0033] STEP202: Assuming that the total volume of the porous copper alloy is V, and the proportion of the pore-forming agent relative to the total volume of the pore-forming agent and the copper alloy powder is A, at this time, the pore volume V*A should be greater than v;

[0034] STEP203: Set the linear expansion coefficient of the copper alloy as α, and the volume expansion coefficient within 25-100℃ as (1+α) 3 -1;

[0035] STEP204: According to statistics, under normal circumstances, the oil temperature is about 60℃, and when an abnormal situation occurs, the temperature rises sharply, and when it rises to about 80℃, due to thermal expansion and capillary action, i.e. low pressure is formed at the oil breakage position, the oil stored in the pores will be squeezed out to the working surface under the pressure difference, and therefore, the change amount of the pore volume needs to meet: V*((1+α)3-1)*(80-60)>v.

[0036] The value of the pore volume of the oil storage capsule 20 can be calculated by the above calculation method. Within the value, the second oil outlet hole 15 can be guaranteed not to discharge oil, and the burning of the shaft and the seizure can be avoided in a short time.

[0037] In step STEP201, the counter-abrading part can be a bearing seat or a shaft sleeve, which is a prior art and will not be described here. Since the bearing 10 needs to rotate in the counter-abrading part, the counter-abrading part and the bearing 10 cannot be tightly fitted, and must have a certain gap. Of course, the gap also has a standard, which is usually 1-2‰ of the diameter of the bearing 10. Therefore, the volume of the gap should also be a range. The pore-forming agent can be graphite.

[0038] In step STEP202, V*A should be the size of the total volume of the pores in the porous copper alloy. Since the pores in the porous copper alloy will be filled with lubricating oil, the size of V*A should be greater than the volume of the gap between the bearing 10 and the counter-abrading part. Therefore, V*A should be greater than v. However, in order to ensure the strength of the porous copper alloy, the pore volume should be less than a certain value, and V*A should be less than 40% of the porous copper alloy.

[0039] In step STEP203, the linear expansion coefficient α of the copper alloy is its inherent property and will not be described here. It can be determined by the top rod indirect method, the telescope direct reading method, and the laser measurement method.

[0040] In step STEP204, the oil temperature of 60 degrees is the temperature when the equipment is normally running. The oil temperature of 80 degrees is the highest temperature in the first few minutes when an abnormal situation occurs, although the temperature starts to rise sharply, before the bearing is burned or seized. When the oil temperature rises from 60 degrees to 80 degrees, due to thermal expansion and capillary action, the oil stored in the pores will be squeezed out to the working surface under the pressure difference, so the volume change of the pores after the temperature change needs to meet: V*((1+α) 3 -1)*(80-60)>v, that is, the volume of the lubricating oil squeezed out by the expansion of the porous copper alloy V*((1+α) 3 -1)*(80-60) should be the total volume of the pore change.

[0041] It is conceivable that V*((1+α) 3 -1)*(80-60) should be less than V*A, so as long as V*((1+α) 3 -1)*(80-60) is greater than v.

[0042] In step STEP104, the sintered porous copper alloy is processed into a shape that fits the accommodation cavity 17, and then fixed in the accommodation cavity 17 by welding, sintering, or bonding.

[0043] Compared with the prior art, the sliding bearing with the oil storage porous structure provided by the present application can prevent the bearing 10 from being damaged or locked in a short time under the conditions of sudden start or stop or accidental oil breakage, and can avoid damaging the entire device, by opening the accommodating cavity 17 on the working surface of the bearing 10 and arranging the oil storage capsule 20 made of the porous sintered copper alloy in the accommodating cavity 17. Since the volume change amount of the pores in the oil storage capsule 20 after temperature change should be greater than v, i.e., V*((1+α)3-1)*(80-60) should be greater than v, the lubricating oil overflowing from the oil storage capsule 20 can still fill the gap between the bearing 10 and the counter-abrasion member when the oil temperature between the bearing 10 and the counter-abrasion member changes from 60 degrees to 80 degrees, so as to prevent the bearing 10 from being damaged or locked in a short time under the conditions of sudden start or stop or accidental oil breakage, and to avoid damaging the entire device. Meanwhile, the porosity V*A of the oil storage capsule 20 should be less than 40% of the total volume of the oil storage capsule 20, so that the mechanical strength of the oil storage capsule 20 can still guarantee normal work, and the quality of the bearing 10 will not be reduced due to the too small mechanical strength of the oil storage capsule 20 and the inability to withstand high-strength friction.

[0044] The above is only the preferred embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement or improvement within the spirit of the present application is covered within the scope of the claims of the present application.

Claims

1. A sliding bearing with an oil-retaining porous structure, characterized in that: The sliding bearing with a porous oil storage structure includes a bearing and at least one oil reservoir on the bearing. The bearing includes a bearing body, multiple oil passages on the bearing body, multiple pairs of first oil outlet holes and first oil return holes on the oil passages, multiple pairs of second oil outlet holes and second oil return holes on the working surface of the bearing body, and multiple cavities at the oil outlet of the second oil outlet holes. The oil reservoir is disposed in the cavities. The oil reservoir is a porous sintered copper alloy part with multiple pores. Let V be the total volume of the oil reservoir, and v be the clearance volume between the grinding element and the bearing. Then the total volume of the oil reservoir should conform to the following formula: V*((1+α) 3 -1)*(80-60)>v Wherein, α is the linear expansion coefficient of the copper alloy, 60 is the temperature of the oil storage capsule during normal operation, and 80 is the temperature of the oil storage capsule when an abnormal situation occurs. Meanwhile, the porosity of the oil storage capsule is less than 40% of the total volume of the oil storage capsule.

2. The sliding bearing with an oil-retaining porous structure as described in claim 1, characterized in that: The free surface of the oil storage capsule is the working surface.

3. The sliding bearing with an oil-retaining porous structure as described in claim 1, characterized in that: The method for calculating the clearance volume between the grinding element and the bearing is as follows: Assuming the bearing has a diameter of d and an axial height of h, and the clearance between the bearing and the mating part is 1-2‰, then the inner ring diameter of the mating part D = d*(1+1‰)~d*(1+2‰), and the clearance volume v between the mating part and the bearing is 0.25*π(D*Dd*d)*h.

4. The sliding bearing with an oil-retaining porous structure as described in claim 1, characterized in that: The porous sintered copper alloy part is formed by sintering a copper alloy with a pore-forming agent, wherein the pore-forming agent is burned off during sintering to form the porous sintered copper alloy part.

5. The sliding bearing with an oil-retaining porous structure as described in claim 4, characterized in that: Let A be the ratio of the volume of the pore-forming agent to the total volume of the copper alloy and graphite before sintering. V*A should be greater than or equal to v.

6. The sliding bearing with an oil-retaining porous structure as described in claim 4, characterized in that: The pore-forming agent is graphite.

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