A space precision bearing lubricating grease supply device and design method thereof

Abstract

A space precision bearing lubricating grease supply device and a design method thereof belong to the technical field of automatic oil supply and long-term lubrication of space micro bearings. It includes an inner and outer sleeve, and lubricating oil is stored between the two sleeves. The upper and lower ends of the inner sleeve are respectively processed with annular bosses A and B, and the outer surfaces of the inner sleeve bosses A and B are tightly fitted with the inner surface of the outer sleeve. A through hole that cooperates with the threaded rod is processed on the annular boss A of the inner sleeve, and an annular groove for placing a rubber ring is provided below the through hole. The oil seepage rate is adjusted by adjusting factors such as the interference fit, surface roughness and rotation speed, so as to control the lubrication time according to the bearing service time and achieve the purpose of controlling the lubrication oil supply rate. The present invention can make full use of the internal space of the bearing device, increase the oil storage capacity, and realize accurate and long-term oil supply, and the oil supply system has a simple structure and high reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of automatic oil supply and long-term lubrication of space micro bearings, and relates to a lubricating grease supply device for space precision bearings and a design method thereof. Background Art

[0002] Spacecraft such as satellites usually fly in outer space for several years. The attitude control flywheel system is an important flight control device. Ultra-precision bearings are the core components of the flywheel rotor system. The bearings require low friction power consumption and high operating precision, and need to carry their own lubricating oil or grease. However, vacuum and semi-vacuum environments are special working conditions. Under such conditions, the bearings are required to carry their own lubricating oil and work for 3-7 years at a time. In addition, the pressure drops, which increases the evaporation of the lubricating oil. Therefore, the lubricating oil / grease that comes with the oil-containing bearing cage often cannot meet the use requirements. It is necessary to carry lubricating oil / grease in a small space and be able to achieve continuous oil supply in the space environment, which puts stringent requirements on the lubrication of the bearings.

[0003] Most of the existing precision bearing oil storage devices in aerospace environments use porous materials or oil supply ropes to provide lubrication for precision bearings. The porous material oil storage lubrication device uses centrifugal force to slowly penetrate the lubricating oil stored in the porous material into the lubrication parts of the bearing. However, there is a contradiction between the oil storage capacity of the device and the material strength. An increase in the designed oil storage capacity will cause a decrease in the designed strength, thereby reducing the service life of the device. In addition, since the device uses porous materials, the lubricating oil will evaporate severely in a vacuum or semi-vacuum environment. In addition, due to the capillary force of the porous material, the lubricating oil will remain in the device and cannot be fully utilized, which makes the lubricating oil supply rate of the device uncontrollable and the lubricating oil utilization efficiency relatively low. The oil supply rope oil storage lubrication device is another commonly used method. The oil rope contacts the tapered sleeve adjacent to the inner ring of the bearing under slight pressure from a spring. The friction generated by this contact causes the oil to continuously migrate along the larger end of the sleeve and enter the bearing under the action of centrifugal force. The oil rope absorbs oil from the oil reservoir and continuously supplies oil to the bearing with the help of capillary action. This device is affected by the machining accuracy, resulting in a faster oil supply rate from the oil supply rope and uncontrollable lubrication oil supply rate.

[0004] According to liquid sealing theory, since there is a functional relationship between the liquid leakage rate and the surface roughness of the structure and the interference contact pressure, based on this, the present invention designs a new type of space precision bearing lubricating grease supply device. Compared with the currently commonly used ultra-precision bearing oil storage lubrication device in aerospace environment, the present invention can adjust the oil seepage rate by adjusting factors such as interference, surface roughness and rotation speed, so as to control the lubrication time according to the bearing service time and achieve the purpose of controlling the lubrication oil supply rate. In addition, since the invention makes full use of the internal space of the bearing device, the oil storage capacity is greatly increased. Compared with the currently commonly used oil storage lubrication device, the oil storage capacity can be 1-2 times more, achieving accurate and long-term oil supply, and the oil supply system has a simple structure and high reliability. Summary of the invention

[0005] Aiming at the shortcomings of existing precision bearing lubrication devices in aerospace environments, such as uncontrollable lubricating oil supply rate and low oil storage, the present invention designs a novel precision bearing oil storage lubrication device in aerospace environments and proposes a corresponding design method. The device adopts a double sleeve interference fit method, and lubricating oil is stored between the two sleeves. When the whole rotates, under the centrifugal effect, the internal lubricating oil continuously leaks out from the contact fit to supply oil to the external bearing device. The novel oil supply device achieves the purpose of controllable oil supply rate and high oil storage.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A space precision bearing lubricating grease supply device comprises an inner sleeve 1 and an outer sleeve 2, lubricating oil 3 is stored between the two sleeves, and a shaft 16 is arranged in the inner sleeve 1.

[0008] The inner sleeve 1 is processed with an annular boss A4 and an annular boss B5 at the upper and lower ends, respectively, and the outer surfaces A6 and B7 of the boss A4 and the boss B5 are processed to a certain degree of roughness. The inner sleeve 1 and the outer sleeve 2 are assembled together in an interference fit manner, so that the outer surfaces A6 and B7 of the bosses at both ends of the inner sleeve 1 are closely fitted with the inner surface 8 of the outer sleeve 2, forming a certain interference amount between 0.001-1mm. Lubricating oil 3 is placed in the cavity formed after the inner sleeve 1 and the outer sleeve 2 are assembled.

[0009] A through hole 9 is machined on the annular boss A4 of the inner sleeve 1, and the through hole 9 consists of two parts. An annular groove 10 is machined on the lower half of the through hole 9 toward the inner side of the annular boss A4, and a rubber ring 11 is placed in the annular groove 10. The rubber ring 11 matches the inner wall of the groove 10, and the rubber ring 11 protrudes from the groove 10, that is, the diameter of the rubber ring 11 is greater than the depth of the annular groove 10. A threaded structure A12 is machined on the upper half of the through hole 9. After the lubricating oil 3 is injected from the through hole 9 into the cavity formed after the inner sleeve 1 and the outer sleeve 2 are assembled, the threaded rod 13 is screwed into the through hole 9 to play a sealing role.

[0010] The threaded rod 13 is composed of two parts: the lower half is a smooth surface 14, and the upper half is provided with a thread structure B15. The thread structure B15 matches the thread structure A12 of the through hole 9, ensuring that the threaded rod 13 can be screwed into the through hole 9. The outer diameter of the part of the threaded rod 13 with the smooth surface 14 is smaller than the inner diameter of the thread structure A12, but larger than the inner diameter of the rubber ring 11 placed in the groove 10, ensuring that after the threaded rod 13 is screwed into the through hole 9, the rubber ring 11 is squeezed to achieve a sealing effect. When the shaft 16 rotates, it will drive the inner sleeve 1 and the outer sleeve 2 to rotate together. The lubricating oil 3 stored in the inner sleeve 1 and the outer sleeve 2 will be squeezed due to inertia. The outer surfaces A6 and B7 of the bosses 4 and 5 at both ends of the inner sleeve 1 are tightly fitted with the inner surface 8 of the outer sleeve 2. However, the outer surfaces A6 and B7 are processed to a certain degree of roughness, and gaps will be formed where they contact the inner surface 8 of the outer sleeve 2. The lubricating oil will be squeezed out from the gap and enter the surrounding bearings, thereby lubricating the bearings.

[0011] A design method for a space precision bearing lubricating grease supply device comprises the following steps:

[0012] The first step is to determine the total time t according to the actual lubrication time required by the device. z , given the initial oil storage volume V0.

[0013] The second step is to determine the target initial leakage rate q of the space precision bearing grease supply device. g1

[0014] The spatial precision bearing lubricating grease supply device generates pressure at the contact point of the internal lubricating oil 3 through centrifugal action, thereby achieving the leakage of the lubricating oil 3 at the contact point between the outer surface A6 and the outer surface B7 of the boss 4 and the boss 5 and the inner surface 8 of the outer sleeve 2. However, as the lubricating oil 3 continues to leak, the pressure generated at the contact point will gradually decrease, resulting in a continuous decrease in the leakage rate. Therefore, the leakage rate is a quantity that changes with time, and its expression is:

[0015]

[0016] Wherein, q0 represents an initial leakage rate at t=0, V0 represents the initial oil storage volume, and t represents time.

[0017] It can be seen from formula (1) that the function of the leakage rate changing with time is only related to the initial leakage rate q0 and the initial oil storage volume V0. Therefore, after determining the initial leakage rate q0 and the initial oil storage volume V0, the time function of the leakage rate can be determined.

[0018] Given the total oil storage volume V0 and total use time t zAnd the desired leakage rate α during the use time, the target initial leakage rate of the structure can be calculated:

[0019]

[0020] Among them, α is the leakage ratio, that is, the ratio of the leaked oil volume to the total oil volume, and its value range is 0 to 1. In practice, it is generally a fixed value determined according to the actual working conditions; t z Indicates the total working time the device is designed to work.

[0021] This determines the target initial leakage rate q of the structure g1 .

[0022] The third step is to determine the lubricating oil supply rate q required by the actual working conditions of the bearing. min , calculate the minimum initial leakage rate q that meets this requirement g2 ;

[0023] From formula (1), it can be found that the leakage rate decreases monotonically with time. If the leakage rate is always greater than q during operation, min , then we need to z When q(t z )≥q min ,Right now The minimum initial leakage rate q that meets this requirement is g2 The following equation should be satisfied:

[0024]

[0025] Among them, q min Indicates the lubricating oil supply rate required for the actual working conditions of the bearing.

[0026] By numerically solving formula (3), we can obtain the minimum initial leakage rate q g2 .

[0027] Step 4: Determine the target initial leakage rate q g1 Is it greater than or equal to the minimum initial leakage rate q g2 : If the condition of being greater than or equal to is approximately satisfied, then the target initial leakage rate q in this case g1 Available; if the target initial leakage rate q g1 Less than the minimum initial leakage rate q g2 If the total oil storage volume V0 is too large, the structural parameters should be readjusted to adjust the total oil storage volume V0, and then substituted back into the second step to recalculate the target initial leakage rate q g1 and the minimum initial leakage rate q in the third step g2 , and re-compare until the requirements are met.

[0028] Step 5: Given the initial interference δ0 and the initial root mean square surface roughness σ0, determine the theoretical initial leakage rate q0 of the space precision bearing lubricating grease supply device under given parameters;

[0029] 1) According to the overall size parameters of the space precision bearing lubricating grease supply device and the given initial interference δ0, the average contact pressure P at the structural contact point (the outer surface A6 and the outer surface B7 of the boss 4 and the boss 5 and the inner surface 8 of the outer sleeve 2) is obtained by finite element calculation. c .

[0030] 2) For the lubricating oil with a total volume of V0, the pressure P of the lubricating oil at the contact point is obtained by finite element calculation: A .

[0031] 3) Average contact pressure P at the contact point c And given the initial RMS surface roughness σ0, the nominal film thickness h at the contact point is obtained according to the following formula (4):

[0032]

[0033] Among them, K represents a constant with a value range of 0.0003-0.003; E′ represents the equivalent elastic modulus; f is an intermediate variable; h represents the nominal film thickness at the contact point; σ represents the root mean square surface roughness; E1 represents the elastic modulus of the inner sleeve; E2 represents the elastic modulus of the outer sleeve; μ1 represents the Poisson's ratio of the inner sleeve; μ2 represents the Poisson's ratio of the outer sleeve.

[0034] 4) According to the obtained nominal film thickness h, the parameters of the lubricating grease supply device and the dynamic viscosity of the lubricating oil, the initial leakage rate q0 of the lubricating grease supply device under specific conditions is calculated:

[0035]

[0036] Among them, Φ x represents the pressure flow factor; L is the length of the contact along the leakage flow direction; B is the circumference of the contact; P A Indicates the pressure of lubricating oil at the contact point; P B It indicates the pressure at the contact point outside the device; μ indicates the dynamic viscosity of the lubricating oil.

[0037] Step 6: Determine the theoretical initial leakage rate q0 and the target initial leakage rate q determined in step 4 g1Whether they are consistent: If the relative error is within 5%, they are considered consistent, and the structure corresponding to the theoretical initial leakage rate q0 can meet the corresponding use requirements; if the difference exceeds 5%, it is necessary to readjust the interference δ and the root mean square surface roughness σ at the contact point, and bring them into the fifth step to replace their initial values ​​to re-solve the theoretical initial leakage q0 until it is consistent with the target initial leakage q g1 The relative error is within 5%.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] Compared with the currently commonly used ultra-precision bearing oil storage and lubrication devices in aerospace environments, the present invention can adjust the oil seepage rate by adjusting factors such as the interference fit, surface roughness and rotational speed, thereby achieving the purpose of controlling the lubrication time according to the bearing service time and controlling the lubrication oil supply rate. In addition, since the invention makes full use of the internal space of the bearing device, the oil storage capacity is greatly improved. Compared with the currently commonly used oil storage and lubrication devices, the oil storage capacity can be 1-2 times more, achieving accurate and long-term oil supply, and the oil supply system has a simple structure and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the assembly of a space precision bearing;

[0041] Figure 2 This is an enlarged view of the space precision bearing lubricating grease supply device;

[0042] Figure 3 This is a partial enlarged view of the space precision bearing grease supply device ( Figure 2 Middle region A); Figure 3 (a) is a schematic diagram of the threaded rod structure. Figure 3 (b) is a schematic diagram of the through hole and annular groove structure;

[0043] Figure 4 This is a partial enlarged view of the space precision bearing grease supply device ( Figure 2 Middle region B);

[0044] Figure 5 This is a design flow chart of a space precision bearing lubricating grease supply device;

[0045] Figure 6 It is the geometrical dimension of the space precision bearing lubricating grease supply device involved in the specific embodiment.

[0046] In the figure: 1 inner sleeve; 2 outer sleeve; 3 lubricating oil; 4 annular boss A; 5 annular boss B; 6 outer surface of boss A; 7 outer surface of boss B; 8 inner surface of outer sleeve; 9 through hole; 10 annular groove; 11 rubber ring; 12 threaded structure A; 13 threaded rod; 14 smooth surface; 15 threaded structure B; 16 shaft. DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with specific embodiments.

[0048] A space precision bearing lubricating grease supply device comprises an inner sleeve 1 and an outer sleeve 2, lubricating oil 3 is stored between the two sleeves, and a shaft 16 is arranged in the inner sleeve 1.

[0049] The inner sleeve 1 is processed with an annular boss A4 and an annular boss B5 at the upper and lower ends, respectively, and the outer surface A6 and the outer surface B7 of the boss A4 and the boss B5 have a processing roughness Ra between 0.1 and 1000 microns. The inner sleeve 1 and the outer sleeve 2 are assembled together in an interference fit manner, so that the outer surface A6 and the outer surface B7 of the bosses at both ends of the inner sleeve 1 are closely fitted with the inner surface 8 of the outer sleeve 2, forming a certain interference amount. Lubricating oil 3 is placed in the cavity formed after the inner sleeve 1 and the outer sleeve 2 are assembled.

[0050] A through hole 9 is machined on the annular boss A4 of the inner sleeve 1, and the through hole 9 consists of two parts. An annular groove 10 is machined on the inner side of the annular boss A4 below the through hole 9, and a rubber ring 11 is placed in the annular groove 10. The rubber ring 11 matches the inner wall of the groove 10, and the rubber ring 11 protrudes from the groove 10, that is, the diameter of the rubber ring 11 is greater than the depth of the annular groove 10. A threaded structure A12 is machined on the upper part of the through hole 9. After the lubricating oil 3 is injected from the through hole 9 into the cavity formed after the inner sleeve 1 and the outer sleeve 2 are assembled, the threaded rod 13 is screwed into the through hole 9 to play a sealing role.

[0051] The threaded rod 13 is composed of two parts: a smooth surface 14 at the bottom and a threaded structure B15 at the top. The threaded structure B15 matches the threaded structure A12 of the through hole 9 to ensure that the threaded rod 13 can be screwed into the through hole 9. The outer diameter of the part of the threaded rod 13 with the smooth surface 14 is smaller than the inner diameter of the threaded structure A12, but larger than the inner diameter of the rubber ring 11 placed in the groove 10, to ensure that after the threaded rod 13 is screwed into the through hole 9, the rubber ring 11 is squeezed to achieve a sealing effect. The supply device can be rotated with the shaft 16 of the bearing or with the outer sleeve of the bearing. Both methods can achieve the oil supply function through centrifugal action.

[0052] A design method for a space precision bearing lubricating grease supply device comprises the following steps:

[0053] The first step is to determine the total lubrication time t according to the actual lubrication time required by the device (under actual working conditions, this is just an example) z =26280H, H represents the time unit: hour. Given the initial oil storage volume V0 = 0.754mL.

[0054] The second step is to determine the target initial leakage rate q of the structure. g1

[0055] Given the total oil storage volume V0 and the usage time t z And the desired leakage rate ratio α = 0.9 during the use time, the target initial leakage rate of the structure can be calculated:

[0056]

[0057] This determines the target initial leakage rate q of the structure g1 .

[0058] The third step is to determine the lubricating oil supply rate q required by the actual working conditions of the bearing. min =3.7×10 -6 mL / H, calculate the minimum initial leakage rate q that meets this requirement g2 :

[0059]

[0060] The minimum initial leakage rate q can be obtained g2 =3×10 -5 mL / h.

[0061] The fourth step, in this embodiment, is to compare q g1 and q g2 Discover g1 >q g2 , so the target initial leakage rate q g1 Available.

[0062] Step 5: Given the initial interference δ0 and the initial RMS surface roughness σ0, determine the theoretical initial leakage rate q0 of the structure under given parameters.

[0063] 1) According to the overall size parameters of the structure and the given initial interference δ0 = 0.01 mm, the average contact pressure P at the contact point of the structure is obtained by finite element calculation method. c =100MPa.

[0064] 2) For the lubricating oil with a total volume of V0 = 0.754 mL, the pressure P of the lubricating oil at the contact point is obtained by finite element calculation: A =6977Pa.

[0065] 3) Average contact pressure P at the contact point c And given the initial RMS surface roughness σ0 = 0.36 μm, the nominal film thickness h at the contact is obtained according to the following formula:

[0066]

[0067] Among them, K = 0.003, E1 = E2 = 210 GPa, μ1 = μ2 = 0.3, and the nominal film thickness h = 0.2572 μm is obtained.

[0068] 4) According to the obtained nominal film thickness h, the parameters of the structure and the properties of the lubricating oil, the initial leakage rate q0 of the structure under specific conditions is calculated:

[0069]

[0070] Among them, Φ x =0.32 represents the pressure flow factor, P B =0 represents the pressure outside the device at the contact point, L = 1mm is the length of the contact point along the leakage flow direction, B = 69.115mm is the circumference of the contact point, and μ = 0.023Pa·s represents the dynamic viscosity of the lubricating oil. Finally, the theoretical initial leakage rate q0 = 3.374×10 -5 mL / H.

[0071] Step 6: Determine the theoretical initial leakage rate q0 and the target initial leakage rate q determined in step 4 g1 If the relative error is within 5%, it is considered consistent. In this embodiment, the relative error is Then the structure corresponding to the theoretical initial leakage rate q0 (interference at the contact point δ0=0.01mm and root mean square surface roughness σ0=0.36μm) can meet the corresponding use requirements.

[0072] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A space precision bearing lubricating grease supply device, It is characterized in that The supply device comprises an inner sleeve (1) and an outer sleeve (2), and the shaft (16) is arranged in the inner sleeve (1); The inner sleeve (1) is processed with an annular boss A (4) and an annular boss B (5) at the upper and lower ends, respectively, and the outer surfaces A (6) and B (7) of the boss A (4) and the boss B (5) are processed with roughness; the inner sleeve (1) and the outer sleeve (2) are assembled in an interference fit manner, so that the outer surfaces A (6) and B (7) of the bosses at both ends of the inner sleeve (1) are tightly fitted with the inner surface (8) of the outer sleeve (2) to form a certain interference; lubricating oil (3) is placed in the cavity formed after the inner sleeve (1) and the outer sleeve (2) are assembled; A through hole (9) is machined on the annular boss A (4) of the inner sleeve (1), and the through hole (9) consists of two parts; an annular groove (10) is machined on the inner side of the lower half of the through hole (9), a rubber ring (11) is placed in the annular groove (10), the rubber ring (11) is matched with the inner wall of the groove (10), and the diameter of the rubber ring (11) is greater than the depth of the annular groove (10); a threaded structure A (12) is machined on the upper half of the through hole (9); after the lubricating oil (3) is injected from the through hole (9) into the cavity formed after the inner sleeve (1) and the outer sleeve (2) are assembled, the threaded rod (13) is screwed into the through hole (9) to play a sealing role; The threaded rod (13) is composed of two parts: the lower half is a smooth surface (14), and the upper half is provided with a thread structure B (15); the thread structure B (15) and the thread structure A (12) of the through hole (9) are mutually matched to ensure that the threaded rod (13) can be screwed into the through hole (9); the outer diameter of the part of the threaded rod (13) with the smooth surface (14) is smaller than the inner diameter of the thread structure A (12), but larger than the inner diameter of the rubber ring (11) placed in the groove (10), so that after the threaded rod (13) is screwed into the through hole (9), the rubber ring (11) is squeezed to achieve a sealing effect; When the shaft (16) rotates, the inner sleeve (1) and the outer sleeve (2) are driven to rotate, and the lubricating oil (3) is squeezed out from the gap at the contact point between the inner sleeve (1) and the outer sleeve (2) and enters the bearing to play a role in lubricating the bearing.

2. A space precision bearing lubricating grease supply device according to claim 1, It is characterized in that The interference fit between the inner sleeve (1) and the outer sleeve is 0.001-1 mm.

3. A design method for the space precision bearing lubricating grease supply device according to claim 1 or 2, It is characterized in that The following steps are involved: The first step is to determine the total time t according to the actual lubrication time required by the device. z , given the initial oil storage volume V 0 ; The second step is to determine the target initial leakage rate q of the space precision bearing grease supply device. g1 The supply device generates pressure at the contact point of the internal lubricating oil (3) through centrifugal action, and the lubricating oil (3) leaks from the contact point between the boss 4 and the boss 5 and the outer sleeve (2); as the lubricating oil (3) continues to leak, the pressure generated at the contact point gradually decreases, resulting in a continuous decrease in the leakage rate. The leakage rate is expressed as: Among them, q 0 represents an initial leakage rate at t = 0, V 0 represents the initial oil storage volume, and t represents the time; For a given total oil storage volume V 0 Total usage time t z And the desired leakage rate α during the use time, the target initial leakage rate of the structure can be calculated: Where α is the leakage ratio, that is, the ratio of the leaked oil volume to the total oil volume, which is determined according to the actual working conditions; t z Indicates the total working time of the device design; Finally, the target initial leakage rate q of the structure is determined g1 ; The third step is to determine the lubricating oil supply rate q required by the actual working conditions of the bearing. min , calculate the minimum initial leakage rate q that meets this requirement g2 ; If the leakage rate is always greater than q during operation min , then we need to z When q(t z )≥q min ,Right now The minimum initial leakage rate q that meets this requirement is g2 The following equation should be satisfied: Among them, q min Indicates the lubricating oil supply rate required for the actual working conditions of the bearing; By numerically solving formula (3), the minimum initial leakage rate q is obtained g2 ; Step 4: Determine the target initial leakage rate q g1 Is it greater than or equal to the minimum initial leakage rate q g2 : If the condition of being greater than or equal to is approximately satisfied, then the target initial leakage rate q in this case g1 Available; if the target initial leakage rate q g1 Less than the minimum initial leakage rate q g2 If there are too many, the structural parameters should be readjusted to adjust the total oil storage volume V 0 , and substitute it back into the second step to recalculate the target initial leakage rate q g1 and the minimum initial leakage rate q in the third step g2 , and re-compare until the requirements are met; Step 5: Given the initial interference δ 0 and the initial RMS surface roughness σ 0 , determine the theoretical initial leakage rate q of the space precision bearing grease supply device under given parameters 0 ; 1) According to the overall size parameters of the space precision bearing grease supply device and the given initial interference delta 0 , the average contact pressure P at the contact point of the structure is obtained by finite element calculation c ; 2) For a total volume of V 0 The lubricating oil is used to calculate the pressure P of the lubricating oil at the contact point. A ; 3) Average contact pressure P at the contact point c And given the initial RMS surface roughness σ 0 , the nominal film thickness h at the contact point is obtained according to the following formula (4): Where K is a constant; E′ is the equivalent elastic modulus; f is an intermediate variable; h is the nominal film thickness at the contact point; σ is the root mean square surface roughness; E 1 Indicates the elastic modulus of the inner sleeve; E 2 Represents the elastic modulus of the outer sleeve; μ 1 Represents the Poisson's ratio of the inner sleeve; μ 2 represents the Poisson's ratio of the outer sleeve; 4) Based on the calculated nominal film thickness h, the parameters of the lubricating grease supply device and the dynamic viscosity of the lubricating oil, calculate the initial leakage rate q of the lubricating grease supply device under specific conditions 0 : Among them, Φ x represents the pressure flow factor; L is the length of the contact along the leakage flow direction; B is the circumference of the contact; P A Indicates the pressure of lubricating oil at the contact point; P B Indicates the pressure outside the device at the contact point; μ indicates the dynamic viscosity of the lubricating oil; Step 6: Determine the theoretical initial leakage rate q 0 The target initial leakage rate q determined in step 4 g1 Whether they are consistent: If the relative error is within 5%, they are considered consistent. The theoretical initial leakage rate q 0 The corresponding structure can meet the corresponding use requirements; if the difference exceeds 5%, it is necessary to readjust the interference δ and the root mean square surface roughness σ at the contact point and bring them into the fifth step to replace their initial values ​​to re-solve the theoretical initial leakage q 0 , until the target initial leakage volume q g1 The relative error is within 5%.

4. The design method of the space precision bearing lubricating grease supply device according to claim 3, It is characterized in that The leakage ratio α has a value range of 0 to 1.

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