Pre-pressing bearing device and pre-pressing adjusting method

Abstract

The invention provides a pre-pressing bearing device and a pre-pressing adjusting method. A preload bearing device (10) is provided with a first angular contact bearing unit (16), a second angular contact bearing unit (18), and a preload applying mechanism (20). A preload applying mechanism (20) applies preload by elastically pressing a first outer ring (172) of a first angular contact bearing unit (16) and a second outer ring (192) of a second angular contact bearing unit (18) in the axial direction. The first preload applying section (52) is disposed between the first outer ring (172) and the second outer ring (192). The second preload applying section (54) is disposed between the second outer ring (192) and the second wall section (42b), and presses the second outer ring (192) toward the first outer ring (172) and the first wall section (42a). Therefore, the preload adjustment after the preload bearing device is assembled can be performed with high precision.

Description

Technical Field

[0001] This invention relates to a preload bearing device and a preload adjustment method. Background Technology

[0002] In the prior art, for example, Japanese Patent Publication No. 2007-113777 discloses a preload bearing device used in a state of applying constant pressure preload to multiple angular contact bearings. Summary of the Invention

[0003] In the aforementioned prior art, an elastic member for applying preload is disposed between the inner ring fastening nut and the inner ring. The preload applied to the angular contact bearing can be adjusted by adjusting the tightness of the inner ring fastening nut. However, because changes in preload are too sensitive to changes in the position of the inner ring fastening nut, it is difficult to adjust the preload. Furthermore, the temperature rise caused by heat generation during operation (rotation) causes changes (increases) in the preload, resulting in a problem where the preload cannot be maintained constant.

[0004] The purpose of this invention is to solve the above-mentioned technical problems.

[0005] The first aspect of the present invention is a preload bearing device, comprising a rotating shaft, a housing, a first angular contact bearing unit, a second angular contact bearing unit, and a preload application mechanism, wherein the housing surrounds the rotating shaft; the first angular contact bearing unit is disposed between the rotating shaft and the housing; the second angular contact bearing unit is disposed between the rotating shaft and the housing in a manner axially away from the first angular contact bearing unit; the preload application mechanism applies preload by elastically pushing a first outer ring (which is the outer ring of the first angular contact bearing unit) and a second outer ring (which is the outer ring of the second angular contact bearing unit) along the axial direction, wherein the first outer ring and the second outer ring are received in an outer ring receiving portion provided in the housing, and the first outer ring and the second outer ring are... The outer ring is disposed between the first wall portion on one side of the outer ring receiving portion along the axial direction and the second wall portion on the other side of the outer ring receiving portion along the axial direction. The first outer ring is disposed between the first wall portion and the second outer ring, and the second outer ring is disposed between the first outer ring and the second wall portion. The preload application mechanism has a first preload application portion and a second preload application portion. The first preload application portion is disposed between the first outer ring and the second outer ring, and pushes the first outer ring toward the first wall portion and pushes the second outer ring toward the second wall portion. The second preload application portion is disposed between the second outer ring and the second wall portion, and pushes the second outer ring toward the first outer ring and the first wall portion.

[0006] The second aspect of the present invention is a preload adjustment method, which is the preload adjustment method of the preload bearing device of the first aspect. It includes a parameter measurement step and a size adjustment step. In the parameter measurement step, a rotation test of the preload bearing device is performed to measure the parameters used for preload adjustment. In the size adjustment step, the size of a specific part of the housing is adjusted according to the parameters, thereby performing preload adjustment.

[0007] According to the present invention, the preload adjustment after the preload bearing device is assembled can be performed with high precision.

[0008] The above-described objectives, features, and advantages should be readily understood through the description of the following embodiments with reference to the accompanying drawings. Attached Figure Description

[0009] Figure 1 This is a cross-sectional view of a spindle assembly with a preload bearing device according to an embodiment of the present invention.

[0010] Figure 2 This is a flowchart of the pre-pressure adjustment method.

[0011] Figure 3 yes Figure 1 The diagram shows a preloaded bearing assembly.

[0012] Figure 4 This is a schematic diagram of the preload bearing device involved in the reference example. Detailed Implementation

[0013] like Figure 1 As shown, a preload bearing assembly 10 is disposed on the spindle assembly 100. The spindle assembly 100 is part of the machine tool and is a rotary drive unit that rotates the tool. The tool is, for example, a drill bit, a grinding wheel, etc. The spindle assembly 100 includes a rotary shaft 12, a housing 14, a motor 15, a first angular contact bearing unit 16, a second angular contact bearing unit 18, and a preload application mechanism 20.

[0014] The rotating shaft 12 is the main shaft portion of the spindle assembly 100. The rotating shaft 12 rotates about axis Ax. Hereinafter, regarding the spindle assembly 100 and its structural components, one side of the rotating shaft 12 along the axial direction (X direction) (X1 direction side) will be referred to as the "top end side" or "top portion," and the other side along the axial direction (X2 direction side) will be referred to as the "base end side" or "base end portion." A tool (not shown) is mounted on the top end portion of the rotating shaft 12.

[0015] The housing 14 is a cylindrical body surrounding the rotating shaft 12. The housing 14 extends axially. The housing 14 has a housing body 22, an end plate 24, and a cover member 26. The housing body 22 has a motor housing portion 28 and a bearing housing portion 30. The motor housing portion 28 surrounds the motor 15. The bearing housing portion 30 surrounds the first angular contact bearing unit 16 and the second angular contact bearing unit 18.

[0016] End plate 24 is fixed to the base end of housing body 22 by fastening components (bolts, etc.) not shown. End plate 24 is an annular component. A plurality of bearings 32 are arranged between the inner circumference of end plate 24 and the rotation shaft 12. Only one bearing 32 may be provided. Cover component 26 is fixed to the top end of housing body 22 by fastening components (bolts, etc.) not shown. Cover component 26 is an annular component.

[0017] Motor 15 is a rotary electric motor for rotating the rotating shaft 12. Motor 15 has a rotor 34 and a stator 36. The rotor 34 is fixed to the rotating shaft 12. The stator 36 is fixed to the housing 14. Specifically, the stator 36 is fixed to the motor housing portion 28 of the housing body 22.

[0018] The first angular contact bearing unit 16 has a plurality of first angular contact bearings 17 arranged axially. In this embodiment, there are two first angular contact bearings 17. An annular first spacer 38 is disposed between the two first angular contact bearings 17. The first spacer 38 has an inner spacer 38a and an outer spacer 38b. In other embodiments, the number of first angular contact bearings 17 may be one or more.

[0019] Each first angular contact bearing 17 has a first inner ring 170, a first outer ring 172, and a first ball 174. The first outer ring 172 of each first angular contact bearing 17 is axially slidable relative to the housing body 22. In each first angular contact bearing 17, the line of action L1 of the force connecting the contact point of the first inner ring 170 and the first ball 174 with the contact point of the first outer ring 172 and the first ball 174 (hereinafter referred to as "first line of action L1") is inclined radially.

[0020] The first line of action L1 is inclined radially relative to the outer diameter side, approaching the second angular contact bearing unit 18. An inner spacer 38a is disposed between the two first inner rings 170. An outer spacer 38b is disposed between the two first outer rings 172. The outer spacer 38b is axially slidable relative to the housing body 22.

[0021] The second angular contact bearing unit 18 has a plurality of second angular contact bearings 19 arranged axially. In this embodiment, there are two second angular contact bearings 19. An annular second spacer 40 is disposed between the two second angular contact bearings 19. The second spacer 40 has an inner spacer 40a and an outer spacer 40b. In other embodiments, the number of second angular contact bearings 19 may be one or more.

[0022] Each second angular contact bearing 19 has a second inner ring 190, a second outer ring 192, and a second ball 194. The second outer ring 192 of each second angular contact bearing 19 is axially slidable relative to the housing body 22. In each second angular contact bearing 19, the line of action L2 of the force connecting the contact point of the second inner ring 190 and the second ball 194 with the contact point of the second outer ring 192 and the second ball 194 (hereinafter referred to as "second line of action L2") is inclined radially.

[0023] The second line of action L2 is inclined radially relative to the first angular contact bearing unit 16 on the outer diameter side. An inner spacer 40a of the second spacer 40 is disposed between the two second inner rings 190. An outer spacer 40b of the second spacer 40 is disposed between the two second outer rings 192. The outer spacer 40b is axially slidable relative to the housing body 22.

[0024] The first outer ring 172 and the second outer ring 192 are housed in the outer ring receiving portion 42 provided in the outer casing 14. The cover member 26 closes one side of the outer ring receiving portion 42. The first outer ring 172 and the second outer ring 192 are disposed between the first wall portion 42a on one side (X1 direction side) of the outer ring receiving portion 42 in the axial direction and the second wall portion 42b on the other side (X2 direction side) of the outer ring receiving portion 42 in the axial direction. The first wall portion 42a forms part of the cover member 26.

[0025] A protrusion 27 protruding toward the first outer ring 172 is provided on the cover member 26. The protrusion 27 abuts against the first outer ring 172 on the top side of the first angular contact bearing unit 16 and pushes the first outer ring 172 axially. The protrusion 27 is annular and extends circumferentially along the housing 14. The housing body 22 has a surrounding wall 44 that extends axially from the second wall portion 42b and surrounds the first outer ring 172 and the second outer ring 192. The first outer ring 172 is disposed between the first wall portion 42a and the second outer ring 192. The second outer ring 192 is disposed between the first outer ring 172 and the second wall portion 42b.

[0026] An annular central spacer 46 is disposed between the first inner ring 170 and the second inner ring 190, which are adjacent to each other along the axial direction. The first angular contact bearing unit 16 and the second angular contact bearing unit 18 are disposed between the annular protrusion 48 provided on the outer periphery of the rotating shaft 12 and the fastening nut 50 installed on the rotating shaft 12. The annular protrusion 48 abuts against the second outer ring 192 of the second angular contact bearing 19 on the base end side of the second angular contact bearing unit 18.

[0027] The fastening nut 50 abuts against the first inner ring 170 of the first angular contact bearing 17 on the top side of the first angular contact bearing unit 16. The fastening nut 50 is disposed on the inner side of the cover member 26. The two first inner rings 170 of the first angular contact bearing unit 16 and the two second inner rings 190 of the second angular contact bearing unit 18 are axially positioned and fixed by the fastening nut 50.

[0028] The preload application mechanism 20 applies preload by elastically pushing the first outer ring 172 of the first angular contact bearing unit 16 and the second outer ring 192 of the second angular contact bearing unit 18 along the axial direction. The preload application mechanism 20 has a first preload application section 52 and a second preload application section 54.

[0029] The first preload application part 52 is disposed between the first outer ring 172 and the second outer ring 192, which are adjacent to each other along the axial direction. The first preload application part 52 pushes the first outer ring 172 toward the first wall portion 42a and pushes the second outer ring 192 toward the second wall portion 42b. The first preload application part 52 is slidable axially relative to the outer casing body 22.

[0030] The first preload application part 52 includes a first pressing member 56, a second pressing member 58, a piston 60, and an elastic member 62. The first pressing member 56 presses against the first outer ring 172. The first pressing member 56 is formed in an annular shape surrounding the rotation shaft 12. The first pressing member 56 has a first abutting protrusion 57 protruding towards the first outer ring 172. The first abutting protrusion 57 is an annular shape extending circumferentially. Multiple first abutting protrusions 57 may be provided at intervals between each other circumferentially.

[0031] The second pressing member 58 presses against the second outer ring 192. The second pressing member 58 is formed in an annular shape surrounding the rotation shaft 12. The second pressing member 58 has a second abutting protrusion 59 protruding towards the second outer ring 192. The second abutting protrusion 59 is annular in shape extending circumferentially. Multiple second abutting protrusions 59 can be arranged at intervals along the circumference. The second pressing member 58 has a receiving groove 64. Multiple receiving grooves 64 are provided. Multiple receiving grooves 64 are arranged at intervals along the circumference of the outer casing 14.

[0032] Piston 60 is disposed between first pressing member 56 and second pressing member 58. Piston 60 abuts against first pressing member 56. A portion of piston 60 is received in receiving groove 64 of second pressing member 58. Multiple pistons 60 are provided. Multiple pistons 60 are arranged at intervals from each other along the circumference of housing 14.

[0033] An elastic member 62 (hereinafter referred to as "first elastic member 62") is disposed between the first pressing member 56 and the second pressing member 58. The first elastic member 62 is disposed between the piston 60 and the second pressing member 58. The first elastic member 62 pushes the piston 60 towards the first pressing member 56. The first elastic member 62 is received in a receiving groove 64. The first elastic member 62 is, for example, a coil spring. The first elastic member 62 may also be composed of a plurality of disc springs arranged axially. A plurality of first elastic members 62 are provided. The plurality of first elastic members 62 are spaced apart from each other circumferentially.

[0034] Furthermore, a receiving groove 64 may be provided on the first pressing member 56. In this case, the piston 60 abuts against the second pressing member 58, and the first elastic member 62 is disposed between the first pressing member 56 and the piston 60.

[0035] The second preload application part 54 is disposed between the adjacent second outer ring 192 and the second wall portion 42b. The second preload application part 54 pushes the second outer ring 192 toward the first outer ring 172 and the first wall portion 42a. The second preload application part 54 has an annular pushing member 66 and an elastic member 68. The annular pushing member 66 is formed in a ring shape surrounding the rotation shaft 12. The annular pushing member 66 pushes the second outer ring 192. The annular pushing member 66 is axially slidable relative to the outer casing body 22. The annular pushing member 66 has a pushing protrusion 67 protruding toward the second outer ring 192. The pushing protrusion 67 is annular and extends circumferentially. Multiple pushing protrusions 67 can be provided at intervals along the circumferential direction.

[0036] The elastic member 68 (hereinafter referred to as "second elastic member 68") pushes the annular pressing member 66 toward the second outer ring 192. The second elastic member 68 is received in a spring mounting slot 70 provided in the second wall portion 42b of the housing body 22. The spring mounting slot 70 may also be provided in a component different from the housing body 22. Multiple second elastic members 68 are provided. The multiple second elastic members 68 are spaced apart from each other in the circumferential direction. Therefore, the multiple spring mounting slots 70 are spaced apart from each other in the circumferential direction.

[0037] The second elastic member 68 is, for example, a helical spring. The second elastic member 68 may be composed of a plurality of disc springs arranged axially. The spring constant of the second elastic member 68 of the second preload application section 54 is smaller than the spring constant of the first elastic member 62 of the first preload application section 52. That is, the spring constant of the second preload application section 54 is smaller than the spring constant of the first preload application section 52. The spring constant of the second elastic member 68 is, for example, 30% to 70% of the spring constant of the first elastic member 62. Alternatively, the spring constant of the second elastic member 68 is, for example, 40% to 60% of the spring constant of the first elastic member 62.

[0038] Next, the preload adjustment method of the preload bearing device 10 will be explained.

[0039] like Figure 2 As shown, the preload adjustment method includes a parameter measurement step S1 and a size adjustment step S2. In the parameter measurement step S1, after assembling the preload bearing assembly 10 (spindle assembly 100), a rotation test of the preload bearing assembly 10 is performed to measure the parameters used for preload adjustment. In the parameter measurement step S1, the preload bearing assembly 10, which is the object of measurement, is in a temporary assembly state. When assembling the preload bearing assembly 10, it is assembled in a manner that is pushed in by a predetermined amount relative to the first outer ring 172. The predetermined push-in amount is the initial value for adjustment, which is the initial protrusion length of the protrusion 27 of the cover member 26. Basically, the initial protrusion length of the protrusion 27 can be preset by predicting the situation of adjusting the protrusion length by cutting the protrusion 27. The parameters include at least the temperature of the first angular contact bearing unit 16 or the second angular contact bearing unit 18. The parameters include the rigidity of the preload bearing assembly 10.

[0040] In the size adjustment process S2, pre-pressure adjustment is performed by adjusting the size of a specific part of the housing 14 based on the parameters obtained through measurement. Specifically, in the size adjustment process S2, pre-pressure adjustment is performed by adjusting (increasing or decreasing) the protrusion length of the protrusion 27 at the specific part.

[0041] In the dimensional adjustment process S2, the preload is calculated based on the temperature determined by the rotation test. In this case, the preload can be calculated (obtained) by referring to a pre-prepared table showing the relationship between temperature and preload (reference table). Then, the push-in amount is adjusted based on the obtained preload. Specifically, after removing the cover component 26 from the outer shell body 22, the protrusion length of the protrusion 27 is adjusted. In this case, the adjustment amount of the push-in amount can be calculated (obtained) by referring to a pre-prepared table showing the relationship between preload and push-in amount (reference table). The larger the push-in amount, the less the preload (details will be explained later). Therefore, when the push-in amount is reduced, the preload increases. The push-in amount can be reduced by cutting (shortening) the protrusion 27.

[0042] After adjusting the size of the protrusion 27 to obtain the desired preload, the preload bearing assembly 10 (spindle assembly 100) is reassembled. Specifically, if the preload obtained based on temperature is smaller than the desired set value (set range), the protrusion 27 is shortened to the set value. On the other hand, if the preload obtained based on temperature is larger than the desired set value, the protrusion 27 is lengthened to the set value. Alternatively, an additional spacer may be provided instead of lengthening the protrusion 27.

[0043] Furthermore, if the temperature measured by the rotation test in parameter measurement step S1 is higher than the temperature reference value (upper temperature limit), a cover member 26 with an increased insertion amount (length of protrusion 27) is prepared, and the preload bearing device 10 is reassembled. When preparing the cover member 26 with an increased insertion amount, the cover member 26 can be machined by increasing the insertion amount. Since the preload decreases when the protrusion length of protrusion 27 is increased, the temperature during rotation also decreases. Furthermore, if the axial rigidity of the preload bearing device 10 obtained by parameter measurement step S1 is lower than the reference value (lower rigidity limit), the preload is increased by reducing the insertion amount.

[0044] Figure 3 This is a schematic diagram of the preload bearing assembly 10. The first movable element 80 and the second movable element 82 are elements that can move axially relative to the housing 14 and the rotating shaft 12. The first movable element 80 represents the two first outer rings 172, the outer spacer 38b, and the first pressing member 56 of the first angular contact bearing unit 16 as a single element. The second movable element 82 represents the second pressing member 58, the two second outer rings 192, the outer spacer 40b, and the annular pressing member 66 of the second angular contact bearing unit 18 as a single element.

[0045] exist Figure 3 In this design, the first ball 174 of the first angular contact bearing unit 16 and the second ball 194 of the second angular contact bearing unit 18 are represented as spring elements (first spring 84 and second spring 86). K1 is the spring constant of the first spring 84 (first ball 174). K2 is the spring constant of the second spring 86 (second ball 194). Ka is the spring constant of the first elastic member 62 of the first preload application section 52. Kb is the spring constant of the second elastic member 68 of the second preload application section 54. Furthermore, K1 and K2 are much larger than Ka and Kb.

[0046] exist Figure 3 The diagram illustrates how the lengths of the first spring 84 and the second spring 86 change according to the magnitude (length) of the push-in relative to the first movable element 80. For example... Figure 3As shown in the figure below, when the pushing amount (the axial relative displacement of the first movable element 80 relative to the housing 14) is increased, the first elastic member 62 of the first preload application part 52 and the second elastic member 68 of the second preload application part 54 contract axially. In this case, since Kb is smaller than Ka, the contraction of the second elastic member 68 is greater than the contraction of the first elastic member 62. On the other hand, the rotating shaft 12 and the housing 14 are axially displaced relative to each other. The result of such contraction of the first elastic member 62 and the second elastic member 68 and the axial relative displacement of the rotating shaft 12 and the housing 14 is the extension of the first spring 84 and the second spring 86. The extension of the first spring 84 and the second spring 86 indicates a decrease in preload. It can be seen that the preload decreases when the pushing amount increases. The extension of each of the first spring 84 and the second spring 86 is much smaller than the increase in the pushing amount. Therefore, the change in preload is small relative to the change in pushing amount. That is, the change in preload is sluggish relative to the change in the amount of feed. Therefore, preload adjustment is easy and can be performed with high precision after assembly.

[0047] on the other hand, Figure 4 This is a schematic diagram of the preload bearing device 10R involved in the comparative example. In the preload bearing device 10R, the movable element 90 is axially displaced relative to the housing 14 by pushing it axially, thus allowing the preload to be adjusted. However, since most of the displacement of the movable element 90 is absorbed as the contraction of the elastic member 92, the elongation of the first spring 84 and the second spring 86 becomes large. Therefore, the change in preload is large compared to the change in the amount of pushing of the movable element 90. That is, since the change in preload is sensitive to the change in the amount of pushing, it is not easy to perform preload adjustment with high precision. In addition, the movable element 90 must be disposed inside the housing 14, and disassembly and subsequent reassembly or a corresponding adjustment mechanism are required to adjust the preload, making preload adjustment difficult.

[0048] Furthermore, in smaller than Figure 3 Under the force in the X2 direction of the spring load (the force of spring compression) of the second elastic component 68, the structural components of the preload bearing device 10 will not move at all. Therefore, the rigidity of the preload bearing device 10 is similar to that of a typical constant pressure preload structure. Figure 4 The preload bearing device 10R is the same. Therefore, no reduction in rigidity in the X2 direction due to the arrangement position and orientation of the second elastic member 68 will occur in the preload bearing device 10.

[0049] Figure 1 The preload bearing device 10 shown in this embodiment can achieve the following effects.

[0050] The preload bearing assembly 10 includes not only a first preload application section 52 disposed between the first angular contact bearing unit 16 and the second angular contact bearing unit 18, but also a second preload application section 54 disposed axially outside the first angular contact bearing unit 16 and the second angular contact bearing unit 18. Therefore, the preload adjustment after the preload bearing assembly 10 is assembled can be performed with high precision.

[0051] The spring constant of the second preload application part 54 (the second elastic member 68) is smaller than the spring constant of the first preload application part 52 (the first elastic member 62). With this structure, high-precision preload adjustment can be performed more reliably.

[0052] The first preload application unit 52 pushes the first outer ring 172 via the first pushing member 56 and pushes the second outer ring 192 via the second pushing member 58. A piston 60 and a first elastic member 62 are disposed between the first pushing member 56 and the second pushing member 58. With this structure, pushing force can be effectively applied to the first angular contact bearing unit 16 and the second angular contact bearing unit 18.

[0053] The first pressing member 56 and the second pressing member 58 are each formed in annular shape, and multiple combinations of piston 60 and first elastic member 62 are arranged at intervals along the circumference. With this structure, axial pressing force can be generated uniformly along the circumference.

[0054] The second preload application part 54 has an annular pushing member 66 and a second elastic member 68, wherein the annular pushing member 66 is formed in a circular shape; the second elastic member 68 pushes the annular pushing member 66 toward the second outer ring 192. With this structure, the pushing force can be effectively applied to the second angular contact bearing unit 18.

[0055] The outer casing 14 has a cover member 26, which is connected to the outer casing body 22 and closes one side of the outer ring receiving portion 42. Preload adjustment can be performed by adjusting the size of the cover member 26. With this structure, preload can be easily adjusted during the preload adjustment process after temporary assembly by adjusting the size of the cover member 26. That is, preload adjustment can be performed with minimal disassembly and reassembly after the assembly of the preload bearing device 10.

[0056] A protrusion 27 protruding toward the first outer ring 172 is provided on the cover component 26. By adjusting the protruding length of the protrusion 27, the preload applied to the first angular contact bearing unit 16 and the second angular contact bearing unit 18 can be adjusted. With this structure, the preload can be easily adjusted by adjusting the size of the protrusion 27.

[0057] Regarding the above-described embodiments, the following notes are further disclosed.

[0058] (Note 1) The preload bearing device (10) of the present invention has a rotating shaft (12), a housing (14), a first angular contact bearing unit (16), a second angular contact bearing unit (18), and a preload application mechanism (20), wherein the housing surrounds the rotating shaft; the first angular contact bearing unit is disposed between the rotating shaft and the housing; the second angular contact bearing unit is disposed between the rotating shaft and the housing in a manner axially away from the first angular contact bearing unit; the preload application mechanism applies preload by elastically pressing a first outer ring (172) which is the outer ring of the first angular contact bearing unit and a second outer ring (192) which is the outer ring of the second angular contact bearing unit along the axial direction, wherein the first outer ring and the second outer ring are received in an outer ring receiving portion (42) provided in the housing. The first outer ring and the second outer ring are disposed between the first wall portion (42a) on one side of the outer ring receiving portion in the axial direction and the second wall portion (42b) on the other side of the outer ring receiving portion in the axial direction. The first outer ring is disposed between the first wall portion and the second outer ring, and the second outer ring is disposed between the first outer ring and the second wall portion. The preload application mechanism has a first preload application portion (52) and a second preload application portion (54), wherein the first preload application portion is disposed between the first outer ring and the second outer ring, and pushes the first outer ring toward the first wall portion and pushes the second outer ring toward the second wall portion; the second preload application portion is disposed between the second outer ring and the second wall portion, and pushes the second outer ring toward the first outer ring and the first wall portion. With this structure, the preload bearing assembly not only has a first preload application section disposed between the first angular contact bearing unit and the second angular contact bearing unit, but also a second preload application section disposed axially outside the first and second angular contact bearing units. Therefore, high-precision preload adjustment after assembly is possible.

[0059] (Note 2) In the preload bearing device described in Note 1, the spring constant of the second preload application part may be smaller than the spring constant of the first preload application part. With this structure, high-precision preload adjustment can be performed more reliably.

[0060] (Note 3) In the preload bearing device described in Note 1 or 2, the first preload application part may have a first pressing member (56), a second pressing member (58), a piston (60), and an elastic member (62), wherein the first pressing member presses the first outer ring; the second pressing member presses the second outer ring; the piston is disposed between the first pressing member and the second pressing member; and the elastic member is disposed between the first pressing member and the second pressing member, pushing the piston toward the first pressing member or the second pressing member. With this structure, a good pressing force can be applied to the first angular contact bearing unit and the second angular contact bearing unit.

[0061] (Appendix 4) In the preload bearing device described in Appendix 3, the first and second pressing components may be formed as annular rings surrounding the rotating shaft. Multiple pistons and elastic components are provided, with the pistons spaced apart from each other along the circumference of the housing, and the elastic components spaced apart from each other along the circumference. With this structure, axial pressing force can be generated uniformly along the circumference.

[0062] (Note 5) In any of the preload bearing devices described in Notes 1 to 4, the second preload application part may have an annular pushing member (66) and an elastic member (68), wherein the annular pushing member (66) is formed in an annular shape surrounding the rotating shaft and pushes the second outer ring; the elastic member pushes the annular pushing member toward the second outer ring. With such a structure, the pushing force can be effectively applied to the second angular contact bearing unit.

[0063] (Appendix 6) In any of Appendices 1 to 5, the preload bearing device has a housing body (22) and a cover member (26), wherein the housing body has the second wall portion and an enclosing wall portion (44) extending axially from the second wall portion and surrounding the first outer ring and the second outer ring; the cover member is connected to the housing body, has the first wall portion, and closes one side of the outer ring receiving portion; by adjusting the size of the cover member, the preload applied to the first angular contact bearing unit and the second angular contact bearing unit can be adjusted. With this structure, in the preload adjustment process after temporary assembly, the preload can be easily adjusted by adjusting the size of the cover member.

[0064] (Note 7) In the preload bearing device described in Note 6, a protrusion (27) protruding toward the first outer ring may be provided on the cover component. With such a structure, the preload can be easily adjusted by adjusting the size of the protrusion.

[0065] (Appendix 8) The preload adjustment method of the present invention is the preload adjustment method of the preload bearing device described in Appendix 1, which has a parameter measurement step (S1) and a size adjustment step (S2). In the parameter measurement step, a rotation test of the preload bearing device is performed to measure the parameters used for preload adjustment. In the size adjustment step, the size of a specific part of the housing is adjusted according to the parameters, thereby performing the preload adjustment.

[0066] (Appendix 9) In the pre-pressure adjustment method described in Appendix 8, the outer shell may have an outer shell body and a cover component, wherein the outer shell body has the second wall portion and a surrounding wall portion extending from the second wall portion along the axial direction and surrounding the first outer ring and the second outer ring; the cover component is connected to the outer shell body, has the first wall portion, and closes one side of the outer ring receiving portion, and a protrusion protruding toward the first outer ring is provided on the cover component, and in the size adjustment process, the pre-pressure adjustment is performed by adjusting the protrusion length of the protrusion, which is the specific part.

[0067] (Note 10) In the preload adjustment method described in Note 8, the parameter may be the temperature of the first angular contact bearing unit or the second angular contact bearing unit, or the rigidity of the preload bearing device.

[0068] The present invention has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of the invention or the spirit of the invention derived from the content described in the technical solution and its equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the above embodiments, the order of each action or the order of each process is shown as an example and is not limited to these. The same applies to the use of numerical values ​​or formulas in the description of the above embodiments.

Claims

1. A preload bearing device, comprising a rotating shaft, a housing, a first angular contact bearing unit, a second angular contact bearing unit, and a preload application mechanism, wherein, The outer casing surrounds the rotating shaft; The first angular contact bearing unit is disposed between the rotating shaft and the housing; The second angular contact bearing unit is disposed between the rotating shaft and the housing in a manner that moves axially away from the first angular contact bearing unit; The preload application mechanism applies preload by elastically pushing the first outer ring (which is the outer ring of the first angular contact bearing unit) and the second outer ring (which is the outer ring of the second angular contact bearing unit) along the axial direction, characterized in that... The first outer ring and the second outer ring are housed in the outer ring receiving portion provided in the outer casing. The first outer ring and the second outer ring are disposed between the first wall portion on one side of the outer ring receiving portion along the axial direction and the second wall portion on the other side of the outer ring receiving portion along the axial direction. The first outer ring is disposed between the first wall portion and the second outer ring. The second outer ring is disposed between the first outer ring and the second wall portion. The preload application mechanism has a first preload application section and a second preload application section, wherein, The first pre-compression application part is disposed between the first outer ring and the second outer ring, and pushes the first outer ring toward the first wall portion and pushes the second outer ring toward the second wall portion; The second pre-compression application part is disposed between the second outer ring and the second wall portion, and pushes the second outer ring toward the first outer ring and the first wall portion.

2. The preload bearing device according to claim 1, characterized in that, The spring constant of the second preload application section is smaller than the spring constant of the first preload application section.

3. The preload bearing device according to claim 1, characterized in that, The first preload application part includes a first pressing component, a second pressing component, a piston, and an elastic component, wherein, The first pressing component presses against the first outer ring; The second pushing component pushes the second outer ring; The piston is disposed between the first pressing component and the second pressing component; The elastic member is disposed between the first pushing member and the second pushing member, and pushes the piston toward the first pushing member or the second pushing member.

4. The preload bearing device according to claim 3, characterized in that, The first pressing component and the second pressing component are respectively formed into annular shapes surrounding the rotation axis. Multiple pistons and multiple elastic components are provided. The plurality of pistons are arranged spaced apart from each other along the circumference of the housing. The plurality of said elastic components are arranged at intervals from each other along the circumferential direction.

5. The preload bearing device according to claim 1, characterized in that, The second preload application part has an annular pushing component and an elastic component, wherein, The annular pushing component is formed in the shape of a ring surrounding the rotating shaft, and pushes the second outer ring; The elastic component pushes the annular pushing component toward the second outer ring.

6. The preload bearing device according to any one of claims 1 to 5, characterized in that, The outer casing has an outer casing body and a cover component, wherein, The outer casing body has the second wall portion and an enclosing wall portion extending from the second wall portion along the axial direction and surrounding the first outer ring and the second outer ring; The cover component is connected to the outer shell body and has the first wall portion, which closes one side of the outer ring receiving portion. By adjusting the size of the cover component, the preload applied to the first angular contact bearing unit and the second angular contact bearing unit can be adjusted.

7. The preload bearing device according to claim 6, characterized in that, The cover component has a protrusion that extends toward the first outer ring.

8. A preload adjustment method, which is the preload adjustment method of the preload bearing device according to claim 1, characterized in that, It has parameter measurement and size adjustment processes, among which, In the parameter measurement process, a rotation test of the preload bearing device is performed to measure the parameters used for preload adjustment. In the size adjustment process, the size of a specific part of the housing is adjusted according to the parameters, thereby performing the pre-pressure adjustment.

9. The pre-pressure adjustment method according to claim 8, characterized in that, The outer casing has an outer casing body and a cover component, wherein, The outer casing body has the second wall portion and an enclosing wall portion extending from the second wall portion along the axial direction and surrounding the first outer ring and the second outer ring; The cover component is connected to the outer shell body and has the first wall portion, which closes one side of the outer ring receiving portion. The cover component is provided with a protrusion that extends toward the first outer ring. In the size adjustment process, the pre-pressure adjustment is performed by adjusting the protrusion length of the protrusion at the specific location.

10. The pre-pressure adjustment method according to claim 8, characterized in that, The parameter is the temperature of the first angular contact bearing unit or the second angular contact bearing unit, or the rigidity of the preload bearing device.

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