Space high-precision hinge back-to-back angular contact bearing pre-tightening device and method

Abstract

The application provides a spatial high-precision hinge back-to-back angular contact bearing pre-tightening device and method, which comprises a T-shaped middle shaft, a nut, a long gasket, a cross cover, an elastic element, a locking screw, an adjusting nut, a pressure sensor and a depth ruler. The application has the beneficial effects that the required shaft sleeve length during positioning and pre-tightening under the optimal pre-tightening force of the angular contact bearing can be determined, and the matrix relationship between the pre-tightening force and the shaft sleeve length can be obtained in the case that the optimal pre-tightening force is uncertain, thereby providing the basis for determining the optimal pre-tightening force and realizing high-precision pre-tightening of the hinge bearing.

Description

Technical Field

[0001] This invention belongs to the field of high-precision hinge bearing preload in spacecraft, and in particular relates to a preload device and method for high-precision back-to-back angular contact bearings in space hinges. Background Technology

[0002] my country is rapidly developing from a major spacefaring nation to a leading spacefaring nation, with the number of various spacecraft constantly increasing and their performance and quality continuously improving. Among the many deployable mechanisms of spacecraft, hinges serve as the joints and power sources of the deployment mechanism. To improve the reliability of hinge deployment in orbit and to bear the axial and radial loads generated on the hinge by the deployment mechanism during spacecraft maneuvering in orbit, back-to-back angular contact bearings are typically used as the friction pair of the hinge. Angular contact bearings must be preloaded to eliminate their own clearance and improve bearing stiffness and rotational accuracy. To meet the requirements of lightweight and high reliability for spacecraft, the hinge bearing preload device should be simple and the method reliable. There are two main types of bearing preload methods: constant force preload and positional preload. Due to the constraints of the space thermal environment and the size and weight of the mechanism, spacecraft hinges usually adopt the positional preload method. During the assembly of spacecraft hinges, the thickness of the bushing is often set empirically to complete the positional preload of the bearing. However, relying on experience has poor accuracy and can easily increase the hinge friction torque or reduce the bearing stiffness. Therefore, it is necessary to develop a bearing preload device and method that can couple constant force preload and positioning preload. Summary of the Invention

[0003] In view of this, the present invention aims to provide a high-precision spatial hinge back-to-back angular contact bearing preload device and method to solve the problem that high-precision preload of hinge bearings cannot be achieved in the prior art.

[0004] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0005] In a first aspect, the present invention provides a spatial high-precision hinge back-to-back angular contact bearing preload device, comprising a T-shaped central shaft, a nut, a long washer, a cross-shaped pressure cap, an elastic element, a locking screw, an adjusting nut, a pressure sensor, and a depth gauge. The cross-shaped pressure cap and the locking screw are installed inside the T-shaped central shaft. A depth gauge mounting interface is provided at the upper end of the T-shaped central shaft for mounting the depth gauge. An elastic element is also sleeved on the outside of the T-shaped central shaft. A pressure sensor is provided above the elastic element. An adjusting nut is provided at the upper end of the pressure sensor. The elastic element, the pressure sensor, and the adjusting nut are sleeved on the outside of the T-shaped central shaft. A long washer is provided at the lower end of the elastic element. A male hinge mounting nut passes through the lower end of the T-shaped central shaft.

[0006] Furthermore, the T-shaped central shaft is also provided with a threaded hole, and the locking screw is installed into the threaded hole to fix the cross-shaped pressure cap.

[0007] Furthermore, the T-shaped central shaft is also provided with a cross-shaped orthogonal long slot through hole, the width of which is greater than the thickness of the cross-shaped pressure cap, for installing the cross-shaped pressure cap, and the cross-shaped pressure cap is installed above the long pad.

[0008] Furthermore, the lower end of the T-shaped central shaft has a section of optical shaft with a diameter smaller than the external thread on both the top and bottom, forming an external relief groove, which is used for tightening and limiting the nut.

[0009] Furthermore, the upper and lower end faces of the long washer are flat and smooth, the inner diameter of the long washer is 0.1mm larger than the outer diameter of the T-shaped central shaft, and the outer diameter of the long washer is equal to the outer diameter of the inner ring of the angular contact bearing.

[0010] Furthermore, the elastic element is a spring, the outer diameter of the spring is smaller than the outer diameter of the long washer, the inner diameter of the spring is larger than the inner diameter of the long washer, and the length of the elastic element when uncompressed does not exceed the reserved length on the T-shaped central axis.

[0011] Secondly, based on the same concept, the present invention also provides a method for pre-tightening a back-to-back angular contact bearing of a high-precision spatial hinge, comprising the following steps: S1, combining the dimensions of the male hinge and the specifications of the angular contact bearing, designing the dimensions of the T-shaped central shaft, locking screw, cross cap, long washer, and nut, selecting elastic elements with appropriate outer diameter and stiffness, and selecting or customizing pressure sensors of appropriate specifications.

[0012] S2. Perform a trial assembly of the bearing preload device and check whether there is any interference between the parts.

[0013] S3. Install the nut at the end of the T-shaped central shaft and tighten it. Use a micrometer or a high-precision coordinate measuring machine to calibrate the distance H1 between the upper end face of the nut and the upper end face of the T-shaped central shaft.

[0014] S4. Use a micrometer to measure the lengths H2 and H3 of the locking screw, the thickness H4 of the cross cap, the thickness H5 of the long washer, and the thicknesses H6 and H7 of the inner ring of the angular contact bearing.

[0015] S5. Install the adjusting nut, pressure sensor, elastic element, and long washer sequentially from the end of the T-shaped shaft onto the T-shaped shaft.

[0016] S6. Install the cross-shaped pressure cap between the long gasket and the pressure sensor through the long slot on the T-shaped central shaft.

[0017] S7. Install the two angular contact bearings back-to-back onto the male hinge, and then install them together on the T-shaped central shaft;

[0018] S8. Install the nut onto the T-shaped central shaft and tighten the nut. The upper end face of the nut restricts the inner ring of the bearing from moving downward.

[0019] S9. By rotating the adjusting nut, the pressure sensor compresses the elastic element downward. When the elastic element is compressed, it generates an axial preload. The pressure sensor reads the axial preload.

[0020] S10. When the axial preload reaches a specific value, stop rotating the adjusting nut and screw the locking screw into the threaded hole at the upper end of the T-shaped central shaft until the locking screw secures the cross cap above the long washer. At this time, observe the pressure sensor to ensure that the pressure sensor reading does not change during the tightening of the locking screw.

[0021] S11. Screw the second locking screw into the T-shaped central shaft to form a double-threaded lock with the first locking screw. During the locking process, ensure that the pressure sensor reading does not change.

[0022] S12. Install the depth gauge on the upper end of the T-shaped central shaft and use the depth gauge to measure the distance H8 between the upper end face of the T-shaped central shaft and the upper end face of the second locking screw.

[0023] S13. Calculate the theoretical length H9 of the bushing according to the following formula;

[0024] H9 = H1 - H2 - H3 - H4 - H5 - H6 - H7 - H8;

[0025] S14. Grind the bushing to the theoretical length H9;

[0026] S15. Remove the male hinge and angular contact bearing from the T-shaped central shaft, and install the refurbished bushing in the hinge to ensure that even if the axial force on the inner ring of the angular contact bearing is greater than its own optimal preload, no axial displacement will occur due to the limitation of the bushing length, thereby achieving axial positioning preload.

[0027] Compared with the prior art, the spatial high-precision hinge back-to-back angular contact bearing preload device and method of the present invention have the following advantages:

[0028] The present invention discloses a spatial high-precision hinge back-to-back angular contact bearing preload device and method, which can determine the bushing length required for positioning preload under the optimal preload force of the angular contact bearing, and can also obtain the matrix relationship between the preload force and the bushing length when the optimal preload force is uncertain, thereby providing a basis for determining the optimal preload force and realizing high-precision preload of the hinge bearing. Attached Figure Description

[0029] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 This is a schematic diagram of the back-to-back angular contact bearing preload device according to an embodiment of the present invention;

[0031] Figure 2 This is a cross-sectional schematic diagram of the back-to-back angular contact bearing preload device according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram illustrating the positioning pre-tightening measurement according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of the T-shaped central axis described in an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of the locking screw described in an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of the cross-shaped pressure cap according to an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of the long pad described in an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of the elastic element described in an embodiment of the present invention;

[0038] Figure 9 This is a schematic diagram of the nut described in an embodiment of the present invention;

[0039] Figure 10 This is a schematic diagram of the pressure sensor described in an embodiment of the present invention;

[0040] Figure 11 This is a schematic diagram of the depth gauge described in an embodiment of the present invention;

[0041] Figure 12 This is a schematic diagram of the bushing according to an embodiment of the present invention;

[0042] Figure 13 This is a schematic diagram of the male hinge as described in an embodiment of the present invention;

[0043] Figure 14 This is a schematic diagram of an angular contact bearing according to an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Depth gauge; 2. T-shaped central shaft; 3. Adjusting nut; 4. Pressure sensor; 5. Elastic element; 6. Long washer; 7. Nut; 8. Locking screw; 9. Cross cap; 10. First angular contact bearing; 11. Bushing; 12. Second angular contact bearing; 13. Male hinge. Detailed Implementation

[0046] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] like Figures 1 to 14As shown, a spatial high-precision hinge back-to-back angular contact bearing preload device consists of a T-shaped central shaft 2, a nut 7, a long washer 6, a cross-shaped pressure cap 9, an elastic element 5, a locking screw 8, an adjusting nut 3, a pressure sensor 4, and a depth gauge 1. The product parts required for bearing preload include a pair of angular contact bearings (first angular contact bearing 10, second angular contact bearing 12), a bushing 11, and a male hinge 13 (i.e., bearing mounting base). The T-shaped central shaft 2 is used to pass through the male hinge 13, and to install angular contact bearings, bushings 11, elastic elements 5, pressure sensors 4, and adjusting nuts 3 back-to-back. A nut 7 is installed at the end of the T-shaped central shaft 2. A threaded hole is provided at the upper section of the T-shaped central shaft 2 for installing a cross-shaped pressure cap 9 and a locking screw 8. A depth gauge mounting interface is provided at the upper end of the T-shaped central shaft 2 for installing a depth gauge 1. The elastic element 5 is a spring of suitable size and stiffness, used to provide axial preload to the bearing through a long washer 6 when compressed. The pressure sensor 4 is connected in series with the elastic element 5 to detect the axial preload applied to the bearing by the elastic element 5 in real time. The adjusting nut 3 moves up and down on the T-shaped central shaft 2 to adjust the bearing's axial preload. The length of the elastic element 5 is adjusted to change the axial preload of the elastic element 5; the locking screw 8 is screwed into the internal threaded hole of the T-shaped central shaft 2 to fix the cross pressure cap 9. The cross pressure cap 9 presses on the long washer 6 to ensure that the long washer 6 is fixed. The locking screws 8 are used in pairs and are locked by double threads; the nut 7 is installed at the end of the T-shaped central shaft 2 to axially fix the angular contact bearings (the first angular contact bearing 10 and the second angular contact bearing 12 are both angular contact ball bearings); the depth gauge 1 is installed at the upper end of the T-shaped central shaft 2. The depth gauge 1 is inserted into the T-shaped central shaft 2. By measuring the axial displacement of the locking screw 8, the theoretical length of the intermediate bushing 11 of the two bearings when a specific axial preload is applied is calculated.

[0051] This invention can determine the length of the bushing 11 required for positioning preload under the optimal preload of the angular contact bearing. It can also obtain a matrix relationship between the preload and the length of the bushing 11 when the optimal preload is uncertain, thus providing a basis for determining the optimal preload. In a preferred embodiment of this invention, the invention includes the following apparatus:

[0052] 1. A T-shaped central shaft 2 passes through angular contact bearings (first angular contact bearing 10 and second angular contact bearing 12) and is installed on male hinge 13. The upper end of the T-shaped central shaft 2 is provided with a depth gauge installation interface, and the lower end is provided with a thread to raise the nut installation interface. The main body of the T-shaped central shaft 2 is a hollow structure with internal threads.

[0053] 2. The aforementioned T-shaped central shaft 2 is provided with a cross-shaped orthogonal elongated slot through hole, the width of which is slightly larger than the thickness of the cross-shaped pressure cap 9, for installing the cross-shaped pressure cap 9.

[0054] 3. Nut 7 is installed at the lower end of the T-shaped central shaft 2. The lower end of the T-shaped central shaft 2 has a section of optical shaft with a diameter smaller than the external thread at both the top and bottom, forming an external relief groove to ensure that nut 7 can be tightened to the limit.

[0055] 4. The threaded end face of the nut 7 is flat and smooth, and it contacts the inner ring of the first angular contact bearing to limit the axial movement of the inner ring of the bearing 1.

[0056] 5. The upper and lower end faces of the long shim 6 are flat and smooth. It is installed on the T-shaped central shaft 2 and contacts the inner ring of the second angular contact bearing. Under the action of the elastic element 5, it squeezes the inner ring of the bearing 2 axially.

[0057] 6. The inner diameter of the long shim 6 is 0.1 mm larger than the outer diameter of the T-shaped shaft 2, and the outer diameter of the long shim 6 is equivalent to the outer diameter of the bearing inner ring.

[0058] 7. The above-mentioned elastic element 5 is a spring of suitable size and stiffness, which is installed on the T-shaped central shaft 2. The outer diameter of the spring is smaller than the outer diameter of the above-mentioned long washer 6, and the inner diameter of the spring is larger than the inner diameter of the above-mentioned long washer 6.

[0059] 8. When the above-mentioned elastic element 5 is not compressed, its length does not exceed the reserved length on the T-shaped central shaft 2, and the stiffness of the elastic element 5 is sufficient to provide an elastic force greater than the optimal preload of the bearing within its own compression range;

[0060] 9. The pressure sensor 4 is installed on the T-shaped central shaft 2 above the elastic element 5 and connected in series with the elastic element 5 to detect the axial compressive force increased by the elastic element 5 in real time.

[0061] 10. The adjusting nut 3 is installed on the T-shaped central shaft 2 above the pressure sensor 4. The upper and lower positions are adjusted by rotating on the T-shaped central shaft 2, which drives the pressure sensor 4 to compress or release the elastic element 5, thereby adjusting the axial preload on the bearing.

[0062] 11. The cross-shaped pressure cap 9 is installed inside the T-shaped central shaft 2 through the long slot hole of the T-shaped central shaft 2, and the "cross" shaped leaflets are pressed on the long pad 6 through the long slot hole;

[0063] 12. The locking screw 8 is screwed into the T-shaped central shaft 2 through the threaded hole at the upper end of the T-shaped central shaft 2 and pressed on the cross pressure cover 9. The locking is completed by using two locking screws 8.

[0064] 13. After the adjusting nut 3 has adjusted the axial preload of the bearing, the long shim 6 is locked in place by the locking screw 8 and the cross cap 9 to ensure that the long shim 6 does not shift during the subsequent depth measurement.

[0065] 14. Depth gauge 1 is installed above the T-shaped central shaft 2 to measure the distance between the inner rings of the two bearings (theoretical length of bushing 11) under a specific preload.

[0066] 15. Before measurement, calibrate the distance H1 between the zero position of the depth gauge 1 and the upper end face of the nut 7, calibrate the lengths H2 and H3 of the two locking screws 8, calibrate the thickness H4 of the cross cap 9, calibrate the thickness H5 of the long washer 6, and calibrate the thicknesses H6 and H7 of the inner rings of the two angular contact bearings.

[0067] 16. After the specific preload is applied by adjusting nut 3, use the probe of depth gauge 1 to measure the depth H8 of the upper end face of locking screw 8. The distance between the inner rings of the two bearings (theoretical length of bushing 11) H9 can be obtained. H9 = H1-H2-H3-H4-H5-H6-H7-H8.

[0068] 17. Grind the length of bushing 11 to H9, and then use bushing 11 to complete the positioning and pre-tightening of back-to-back angular contact bearings.

[0069] A method for pre-tightening a back-to-back angular contact bearing of a high-precision spatial hinge includes the following specific steps: a. Based on the dimensions of the male hinge 13 (bearing mounting seat) of the spatial hinge and the specifications of the angular contact bearing, design the dimensions of the T-shaped central shaft 2, locking screw 8, cross cap 9, long washer 6, and nut 7, select an elastic element 5 with appropriate outer diameter and stiffness, and select or customize a pressure sensor 4 with appropriate specifications.

[0070] b. Refer to Appendix Figure 1 and attached Figure 2 Perform a trial assembly of the bearing preload device and check whether there is any interference between the parts.

[0071] c. Install nut 7 at the end of T-shaped central shaft 2 and tighten it, then attach the attached... Figure 3 As shown, use a micrometer or high-precision coordinate measuring machine to calibrate the distance H1 from the upper end face of the nut 7 to the upper end face of the T-shaped central axis 2;

[0072] d. Use a micrometer to measure the lengths H2 and H3 of the locking screw 8, the thickness H4 of the cross cap 9, the thickness H5 of the long washer 6, and the thicknesses H6 and H7 of the inner ring of the angular contact bearing;

[0073] e. Install the adjusting nut 3, pressure sensor 4, elastic element 5, and long washer 6 sequentially from the end of the T-shaped central shaft 2 onto the T-shaped central shaft 2;

[0074] f. Install the cross-shaped pressure cap between the long gasket 6 and the pressure sensor 4 through the cross-shaped orthogonal long slot through hole on the T-shaped central shaft 2;

[0075] g. Install the two angular contact bearings back to back onto the male hinge 13 (bearing mounting seat), and install them together on the T-shaped central shaft 2;

[0076] h. Install nut 7 onto T-shaped central shaft 2 and tighten nut 7. The upper end face of nut 7 restricts the inner ring of the bearing from moving downward.

[0077] i. By rotating the adjusting nut 3, the pressure sensor 4 compresses the elastic element 5 downward. When the elastic element 5 is compressed, an axial preload is generated. The axial preload is read by the pressure sensor 4.

[0078] j. When the axial preload reaches a specific value, stop rotating the adjusting nut 3 and screw the locking screw 8 into the threaded hole at the upper end of the T-shaped central shaft 2 until the locking screw 8 fastens the cross pressure cap 9 above the long washer 6. At this time, the pressure sensor 4 should be observed to ensure that the reading of the pressure sensor 4 does not change during the tightening process of the locking screw 8.

[0079] k. Screw the second locking screw 8 into the T-shaped central shaft 2 to form a double-threaded lock with the first locking screw 8. During the locking process, ensure that the reading of the pressure sensor 4 does not change.

[0080] 1. Install the depth gauge 1 on the upper end of the T-shaped central shaft 2, and use the depth gauge 1 to measure the distance H8 between the upper end face of the T-shaped central shaft 2 and the upper end face of the second locking screw 8;

[0081] m. Calculate the theoretical length H9 of bushing 11 according to the following formula: H9 = H1 - H2 - H3 - H4 - H5 - H6 - H7 - H8;

[0082] n. Grind bushing 11 to its theoretical length H9;

[0083] o. Remove the male hinge 13 (bearing mounting seat) and the angular contact bearing from the T-shaped central shaft 2, and install the above-mentioned ground bushing 11 in the hinge to ensure that even if the axial force on the inner ring of the angular contact bearing is greater than its own optimal preload, no axial displacement will occur due to the limitation of the length of the bushing 11, thereby achieving axial positioning preload.

[0084] Example 1

[0085] a. A spatial high-precision hinge back-to-back angular contact bearing preload device, as shown in the attached document. Figure 1 ~Appendix Figure 14 As shown, the components include a T-shaped central shaft 2, a nut 7, a long washer 6, a cross-shaped pressure cap 9, an elastic element 5, a locking screw 8, an adjusting nut 3, a pressure sensor 4, and a depth gauge 1. The parts required for bearing pre-tightening include a pair of 708C angular contact bearings, a male hinge 13 (bearing mounting seat), and a bushing 11.

[0086] b. Refer to Appendix Figure 1 and attached Figure 2 Perform a trial assembly of the bearing preload device and check whether there is any interference between the components.

[0087] c. Install nut 7 at the end of T-shaped central shaft 2 and tighten it, then attach the attached... Figure 3 As shown, using a micrometer or high-precision coordinate measuring machine, the distance H1 from the upper end face of the nut 7 to the upper end face of the T-shaped central shaft 2 is calibrated to be 125.617mm.

[0088] d. Use a micrometer to measure the total thickness of the two locking screws 8 and the cross cap 9, H2+H3+H4=20.987, the thickness of the long washer 6, H5=6.002mm, and the thickness of the inner ring of the angular contact bearing, H6=6.962mm and H7=6.973mm.

[0089] e. Install the adjusting nut 3, pressure sensor 4, elastic element 5, and long washer 6 sequentially from the end of the T-shaped central shaft 2 onto the T-shaped central shaft 2.

[0090] f. Install the cross-shaped pressure cap between the long gasket 6 and the pressure sensor 4 through the long slot on the T-shaped central shaft 2.

[0091] g. Install the two angular contact bearings back to back onto the male hinge 13 (bearing mounting seat), and together install them onto the T-shaped central shaft 2.

[0092] h. Install nut 7 onto the T-shaped central shaft 2 and tighten nut 7. The upper end face of nut 7 restricts the inner ring of the bearing from moving downward.

[0093] i. By rotating the adjusting nut 3, the pressure sensor 4 compresses the elastic element 5 downward. When the elastic element 5 is compressed, an axial preload is generated. The axial preload is read by the pressure sensor 4.

[0094] j. When the axial preload reaches the optimal preload of 10N, stop rotating the adjusting nut 3 and screw the locking screw 8 into the threaded hole at the upper end of the T-shaped central shaft 2 until the locking screw 8 secures the cross pressure cap 9 above the long washer 6. At this time, the pressure sensor 4 should be observed to ensure that the reading of the pressure sensor 4 does not change during the tightening process of the locking screw 8.

[0095] k. Screw the second locking screw 8 into the T-shaped central shaft 2 to form a double-threaded lock with the first locking screw 8. During the locking process, ensure that the reading of the pressure sensor 4 does not change.

[0096] 1. Install the depth gauge 1 on the upper end of the T-shaped central shaft 2, and use the depth gauge 1 to measure the distance H8 between the upper end face of the T-shaped central shaft 2 and the upper end face of the second locking screw 8, which is 53.704mm.

[0097] m. The theoretical length H9 of bushing 11 is calculated to be 30.989 mm according to the following formula;

[0098] H9 = H1 - H2 - H3 - H4 - H5 - H6 - H7 - H8.

[0099] n. The actual length of bushing 11 after grinding is 30.989mm.

[0100] o. Remove the male hinge 13 (bearing mounting seat) and the angular contact bearing from the T-shaped central shaft 2, and install the above-mentioned ground bushing 11 in the hinge to ensure that even if the axial force on the inner ring of the angular contact bearing is greater than its own optimal preload, no axial displacement will occur due to the limitation of the length of the bushing 11, thereby achieving axial positioning preload.

[0101] After multiple preload conditions of the spatial hinge bearing, the spatial high-precision hinge back-to-back angular contact bearing preload device and method can achieve high-precision preload of the hinge bearing.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A spatial high-precision hinge back-to-back angular contact bearing preload device, characterized in that: The device includes a T-shaped central shaft (2), a nut (7), a long washer (6), a cross-shaped pressure cap (9), an elastic element (5), a locking screw (8), an adjusting nut (3), a pressure sensor (4), and a depth gauge (1). The cross-shaped pressure cap (9) and the locking screw (8) are installed inside the T-shaped central shaft (2). The upper end of the T-shaped central shaft (2) has an interface for installing the depth gauge (1). An elastic element (5) is also sleeved on the outside of the T-shaped central shaft (2). A pressure sensor (4) is provided above the elastic element (5). The pressure sensor (4) is provided with an adjusting nut (3) at its upper end, and the elastic element (5), pressure sensor (4), and adjusting nut (3) are sleeved on the outside of the T-shaped central shaft (2). The elastic element (5) is provided with a long washer (6) at its lower end. The elastic element (5) is used to provide axial preload to the bearing through the long washer (6) when compressed. The pressure sensor (4) is used to detect the axial preload applied to the bearing by the elastic element (5) in real time. The lower end of the T-shaped central shaft (2) is also fitted with a nut (7) through a male hinge (13). The T-shaped central shaft (2) is also provided with a threaded hole, and the locking screw (8) is installed into the threaded hole. The locking screw (8) is used to fix the cross pressure cap (9). The T-shaped central shaft (2) is also provided with a cross-shaped orthogonal long slot through hole. The width of the cross-shaped orthogonal long slot through hole is greater than the thickness of the cross-shaped pressure cap (9) for installing the cross-shaped pressure cap (9). The cross-shaped pressure cap (9) is installed above the long pad (6).

2. The spatial high-precision hinge back-to-back angular contact bearing preload device according to claim 1, characterized in that: The lower end of the T-shaped central shaft (2) has a section of optical shaft with a diameter smaller than the external thread at both the top and bottom, forming an external relief groove. The external relief groove is used for tightening and limiting the nut (7).

3. The spatial high-precision hinge back-to-back angular contact bearing preload device according to claim 1, characterized in that: The upper and lower end faces of the long washer (6) are flat and smooth. The inner diameter of the long washer (6) is 0.1 mm larger than the outer diameter of the T-shaped central shaft (2). The outer diameter of the long washer (6) is equal to the outer diameter of the inner ring of the angular contact bearing.

4. The spatial high-precision hinge back-to-back angular contact bearing preload device according to claim 1, characterized in that: The elastic element (5) is a spring. The outer diameter of the spring is smaller than the outer diameter of the long washer (6), and the inner diameter of the spring is larger than the inner diameter of the long washer (6). When the elastic element (5) is not compressed, its length does not exceed the reserved length on the T-shaped central shaft (2).

5. A method for pre-tightening a back-to-back angular contact bearing of a spatial high-precision hinge, applied to the pre-tightening device for a back-to-back angular contact bearing of a spatial high-precision hinge as described in any one of claims 1-4, characterized in that: Includes the following steps: S1. Based on the dimensions of the male hinge (13) and the specifications of the angular contact bearing, design the dimensions of the T-shaped central shaft (2), locking screw (8), cross cap (9), long washer (6), and nut (7), select an elastic element (5) with appropriate outer diameter and stiffness, and select or customize a pressure sensor (4) with appropriate specifications. S2. Perform a trial assembly of the bearing preload device and check whether there is any interference between the parts. S3. Install the nut (7) at the end of the T-shaped central shaft (2) and tighten it. Use a micrometer or a high-precision three-coordinate measuring machine to calibrate the distance H1 between the upper end face of the nut (7) and the upper end face of the T-shaped central shaft (2). S4. Use a micrometer to measure the lengths H2 and H3 of the locking screw (8), the thickness H4 of the cross cap (9), the thickness H5 of the long washer (6), and the thicknesses H6 and H7 of the inner ring of the angular contact bearing. S5. Install the adjusting nut (3), pressure sensor (4), elastic element (5), and long washer (6) from the end of the T-shaped shaft (2) onto the T-shaped shaft (2) in sequence; S6. Install the cross-shaped pressure cap (9) between the long gasket (6) and the pressure sensor (4) through the cross-shaped orthogonal long slot through hole on the T-shaped central shaft (2); S7. Install the two angular contact bearings back to back onto the male hinge (13) and install them together on the T-shaped central shaft (2); S8. Install the nut (7) onto the T-shaped central shaft (2), tighten the nut (7), and restrict the inner ring of the bearing from moving downwards on the upper end face of the nut (7); S9. By rotating the adjusting nut (3), the pressure sensor (4) is compressed downwards to compress the elastic element (5). When the elastic element (5) is compressed, an axial preload is generated. The axial preload is read by the pressure sensor (4). S10. When the axial preload reaches a specific value, stop rotating the adjusting nut (3) and screw the locking screw (8) into the threaded hole at the upper end of the T-shaped central shaft (2) until the locking screw (8) secures the cross cap (9) above the long washer (6). At this time, observe the pressure sensor (4) to ensure that the reading of the pressure sensor (4) does not change during the tightening process of the locking screw (8). S11. Screw the second locking screw (8) into the T-shaped central shaft (2) to form a double-threaded lock with the first locking screw (8). During the locking process, ensure that the reading of the pressure sensor (4) does not change. S12. Install the depth gauge (1) on the upper end of the T-shaped central shaft (2) and use the depth gauge (1) to measure the distance H8 between the upper end face of the T-shaped central shaft (2) and the upper end face of the second locking screw (8); S13. Calculate the theoretical length H9 of bushing (11) according to the following formula; H9 = H1 - H2 - H3 - H4 - H5 - H6 - H7 - H8; S14. Grind the bushing (11) to the theoretical length H9; S15. Remove the male hinge (13) and angular contact bearing from the T-shaped central shaft (2), and install the honed bushing (11) in the hinge to ensure that even if the axial force on the inner ring of the angular contact bearing is greater than its own optimal preload, it will not undergo axial displacement under the limitation of the length of the bushing (11), thereby achieving axial positioning preload.

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