Transmission assembly and speed reduction equipment

Abstract

The invention discloses a transmission assembly and speed reduction equipment. The transmission assembly comprises an eccentric shaft and a needle bearing. The eccentric shaft comprises a shaft body and an eccentric part. The eccentric part is connected with the shaft. The axis of the eccentric part is parallel to the axis of the shaft body. The needle bearing comprises an outer ring and a needle roller. The at least two roller pins are arranged around the axis of the outer ring and rotationally connected with the outer ring. And the eccentric part penetrates through the outer ring. The outer side wall of the eccentric part abuts against the outer side wall of the roller pin. The transmission assembly is configured to enable the ratio of the surface roughness of the outer side wall of the eccentric part to the surface roughness of the outer side wall of the roller pin to be within a first preset range. The first preset range can be determined through the oil film specific thickness between the eccentric part and the roller pin. The first preset range is determined according to the oil film specific thickness between the eccentric part and the needle roller, and the ratio of the surface roughness of the outer side wall of the eccentric part to the surface roughness of the outer side wall of the needle roller is within the first preset range, so that the abrasion of the needle roller bearing and the eccentric part can be reduced, and the service life of the bearing is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of reduction transmission, and in particular to a transmission component and a reduction device. Background Art

[0002] The cycloid transmission reducer is the core component of industrial robots, and its service life largely determines the working life of the robot. Industrial robots are mainly deployed in production lines, which need to operate continuously, so the life of the reducer is particularly important.

[0003] There are many bearings inside the reducer, and the life of the bearings greatly affects the service life of the reducer. However, the matching degree between the relevant parts and the bearings is the key factor in determining its service life, so how to extend the life of the bearings is crucial. Summary of the invention

[0004] The embodiments of the present invention provide a transmission assembly and a reduction device to solve at least one of the above-mentioned technical problems.

[0005] A transmission assembly according to an embodiment of the present invention comprises:

[0006] An eccentric shaft, wherein the eccentric shaft comprises a shaft body and an eccentric portion, wherein the eccentric portion is connected to the shaft body, and an axis of the eccentric portion is parallel to an axis of the shaft body;

[0007] A needle roller bearing, the needle roller bearing comprising an outer ring and needle rollers, at least two needle rollers are arranged around the axis of the outer ring and rotatably connected to the outer ring, the eccentric portion passes through the outer ring, and the outer side wall of the eccentric portion abuts against the outer side wall of the needle rollers;

[0008] The transmission assembly is configured so that the ratio of the surface roughness of the outer wall of the eccentric portion to the surface roughness of the outer wall of the needle roller is within a first preset range, and the first preset range can be determined by the specific thickness of the oil film between the eccentric portion and the needle roller.

[0009] In the above-mentioned transmission assembly, the first preset range is determined by the relative thickness of the oil film between the eccentric part and the needle roller. The ratio of the surface roughness of the outer wall of the eccentric part to the surface roughness of the outer wall of the needle roller is within the first preset range, which is beneficial to improve the matching degree between the needle roller bearing and the eccentric part, thereby reducing the wear of the needle roller bearing and the eccentric part and increasing the service life of the bearing.

[0010] In certain embodiments, the transmission assembly is configured so that the oil film specific thickness is within a second preset range, and the second preset range can be determined based on a preset coefficient and a value interval of the diameter of the eccentric portion.

[0011] In some embodiments, the preset coefficients include an eccentric shaft speed coefficient, an outer ring inner diameter coefficient and a bearing lubrication coefficient. The eccentric shaft speed coefficient corresponds to the speed of the eccentric shaft, and each different range of values ​​for the diameter of the eccentric portion has a corresponding inner diameter coefficient of the outer ring.

[0012] In some embodiments, the specific thickness of the oil film between the eccentric portion and the needle roller can be obtained by the following formula:

[0013] λ=R×D×M,

[0014] Wherein, λ represents the specific thickness of the oil film, R represents the rotation speed coefficient of the eccentric shaft, D represents the inner diameter coefficient of the outer ring, and M represents the bearing lubrication coefficient.

[0015] In some embodiments, the bearing lubrication coefficient is obtained by the following formula:

[0016] M=T×A,

[0017] Wherein, M represents the bearing lubrication coefficient, T represents the bearing type coefficient, and A represents the lubricant viscosity coefficient.

[0018] In some embodiments, the preset range is [0.5, 4].

[0019] In certain embodiments, the specific thickness of the oil film between the eccentric portion and the needle roller is calculated by the oil film thickness and the composite surface roughness;

[0020] The oil film thickness is the thickness of the oil film between the eccentric portion and the needle roller, and the composite surface roughness corresponds to the surface roughness of the outer wall of the eccentric portion and the surface roughness of the outer wall of the needle roller.

[0021] In some embodiments, the first preset range is [0.5, 4].

[0022] In some embodiments, the second preset range is [1.3770, 3.9984].

[0023] In some embodiments, the preset coefficient further includes the oil film thickness compensation coefficient, and the oil film thickness compensation coefficient is used to compensate for the deviation of the oil film thickness between the eccentric portion and the needle roller;

[0024] The value range of the oil film thickness compensation coefficient is [0.5, 0.7].

[0025] A deceleration device according to an embodiment of the present invention includes the transmission assembly described in any one of the above embodiments.

[0026] In the above-mentioned reduction device, the first preset range is determined by the relative thickness of the oil film between the eccentric part and the needle roller. The ratio of the surface roughness of the outer wall of the eccentric part to the surface roughness of the outer wall of the needle roller is within the first preset range, which is beneficial to improve the matching degree between the needle roller bearing and the eccentric part, thereby reducing the wear of the needle roller bearing and the eccentric part and increasing the service life of the bearing.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0029] Figure 1 It is a partial structural schematic diagram of a deceleration device according to an embodiment of the present invention;

[0030] Figure 2 is a schematic structural diagram of an eccentric shaft according to an embodiment of the present invention;

[0031] Figure 3 is a schematic structural diagram of a needle roller bearing according to an embodiment of the present invention;

[0032] Figure 4 is a schematic diagram of a curve showing a relationship between an eccentric shaft speed and an eccentric shaft speed coefficient according to an embodiment of the present invention;

[0033] Figure 5 1 is a schematic diagram of a curve showing the relationship between the inner diameter of the outer ring and the inner diameter coefficient of the outer ring according to an embodiment of the present invention;

[0034] Figure 6 is a schematic diagram of a relationship curve between lubricant viscosity and lubricant viscosity coefficient according to an embodiment of the present invention;

[0035] Figure 7 It is a schematic structural diagram of a cycloidal wheel according to an embodiment of the present invention.

[0036] Reference numerals:

[0037] 100, transmission assembly; 10, eccentric shaft; 12, eccentric part; 14, shaft body; 20, needle roller bearing; 22, outer ring; 24, mounting hole; 26, through hole; 28, needle roller; 30, cycloid wheel; 32, eccentric hole;

[0038] 200. Speed ​​reduction device. DETAILED DESCRIPTION

[0039] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0043] The disclosure herein provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described herein. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the examples of various specific processes provided by the present invention, but those of ordinary skill in the art can be aware of the application of other processes.

[0044] Please refer to Figure 1 , Figure 2 and Figure 3 A transmission assembly 100 according to an embodiment of the present invention includes an eccentric shaft 10 and a needle roller bearing 20. The eccentric shaft 10 includes a shaft body 14 and an eccentric portion 12. The eccentric portion 12 is connected to the shaft body 14. The axis of the eccentric portion 12 is parallel to the axis of the shaft body 14. The needle roller bearing 20 includes an outer ring 22 and a needle roller 28. At least two needle rollers 28 are arranged around the axis of the outer ring 22 and are rotatably connected to the outer ring 22. The eccentric portion 12 passes through the outer ring 22. The outer wall of the eccentric portion 12 abuts against the outer wall of the needle roller 28. The transmission assembly 100 is configured so that the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 is within a first preset range. The first preset range can be determined by the relative thickness of the oil film between the eccentric portion 12 and the needle roller 28.

[0045] In the above-mentioned transmission assembly 100, the first preset range is determined by the relative thickness of the oil film between the eccentric portion 12 and the needle roller 28, and then the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 is made to be within the first preset range, which is beneficial to improving the matching degree between the needle roller bearing 20 and the eccentric portion 12, thereby reducing the wear of the needle roller bearing 20 and the eccentric portion 12 and increasing the service life of the bearing.

[0046] Specifically, in Figure 1 In the illustrated embodiment, the transmission assembly 100 can be used for a speed reducer (not shown). The eccentric shaft 10 can be provided with two eccentric portions 12. The two eccentric portions 12 can be connected to each other and connected at a middle position close to the shaft body 14. The axis of one eccentric portion 12 close to one end of the shaft body 14 can be represented by P1. The other eccentric portion 12 close to the other end of the shaft body 14 can be represented by P2. The axis of the shaft body 14 can be represented by P3. The axis P1 of one eccentric portion 12 can be parallel to the axis P3 of the shaft body 14. The axis P2 of the other eccentric portion 12 can be parallel to the axis P3 of the shaft body 14.

[0047] The needle roller bearing 20 may be provided with an outer ring 22 and needle rollers 28. The outer ring 22 may be annular. The axis of the outer ring 22 may be represented by P0. A plurality of needle rollers 28 may be provided. A plurality of needle rollers 28 may be arranged around the axis P0 of the outer ring 22. A mounting hole 24 for mounting the needle rollers 28 may be provided on the side wall of the outer ring 22. The needle rollers 28 may be partially arranged in the mounting hole 24 and rotatably connected to the outer ring 22.

[0048] The outer ring 22 may be provided with a through hole 26. In one embodiment, when the transmission assembly 100 is installed, the eccentric portion 12 may be inserted into the through hole 26. When the eccentric portion 12 is provided with the through hole 26, the outer wall of the eccentric portion 12 may abut against the outer wall of the needle roller 28. In one embodiment, the eccentric portion 12 may rotate in the through hole 26 and may drive the needle roller 28 to rotate.

[0049] In the transmission assembly 100, the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 may be within a first preset range. In one embodiment, the first preset range may be determined by the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28. That is, the first preset range is determined by the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28, so that a setting standard for the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 can be given, which can help improve the matching degree between the needle roller bearing 20 and the eccentric portion 12, thereby reducing the wear of the needle roller bearing 20 and the eccentric portion 12 and improving the service life of the bearing.

[0050] Please combine Figure 1 and Figure 2 In some embodiments, the transmission assembly 100 is configured so that the oil film thickness ratio is within a second preset range. The second preset range can be determined based on a preset coefficient and a value interval of the diameter of the eccentric portion 12.

[0051] In this way, the preset coefficient can be determined.

[0052] Specifically, in some embodiments, the oil film thickness ratio may be set to a standard, that is, set within a second preset range. The second preset range may be determined based on a preset coefficient and a value interval of the diameter of the eccentric portion 12. For example, when the diameter of the eccentric portion 12 is in the range of 20 mm to 30 mm and the preset coefficient is known, a corresponding second preset range interval may be determined; when the diameter of the eccentric portion 12 is in the range of 40 mm to 50 mm and the preset coefficient is known, another corresponding second preset range interval may be determined. mm may represent the length unit millimeter.

[0053] In some embodiments, the preset coefficients include the speed coefficient of the eccentric shaft 10, the inner diameter coefficient of the outer ring 22, and the bearing lubrication coefficient. The speed coefficient of the eccentric shaft 10 corresponds to the speed of the eccentric shaft 10. Each different range of values ​​of the diameter of the eccentric portion 12 has a corresponding inner diameter coefficient of the outer ring 22.

[0054] In this way, the speed coefficient of the eccentric shaft 10, the inner diameter coefficient of the outer ring 22 and the bearing lubrication coefficient can be determined respectively.

[0055] Specifically, the following Table 1 may be a data parameter table for calculating the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28:

[0056]

[0057] Table 1

[0058] Wherein, d may represent the diameter of the eccentric portion 12, D may represent the inner diameter coefficient of the outer ring 22, M may represent the bearing lubrication coefficient, R may represent the speed coefficient of the eccentric shaft 10, and ξ may represent the oil film thickness compensation coefficient. The unit of the diameter of the eccentric portion 12 may be millimeter (mm). The value of R is related to the speed of the eccentric shaft 10.

[0059] Based on Table 1, in one example, when the diameter of the eccentric portion 12 has a value interval of 20≤d<30 and the inner diameter coefficient of the outer ring 22 is 0.9, it can be determined that the bearing lubrication coefficient is 0.51.

[0060] In another example, when the diameter of the eccentric portion 12 has a value interval of 30≤d<40 and the inner diameter coefficient of the outer ring 22 is 1.1, it can be determined that the bearing lubrication coefficient is 0.51.

[0061] In another example, when the diameter of the eccentric portion 12 has a value interval of 40≤d<50 and the inner diameter coefficient of the outer ring 22 is 0.9, it can be determined that the bearing lubrication coefficient is 0.51.

[0062] In another example, when the diameter of the eccentric portion 12 has a value interval of 50≤d<60 and the inner diameter coefficient of the outer ring 22 is 0.9, it can be determined that the bearing lubrication coefficient is 0.51.

[0063] It is understandable that in other embodiments, there may also be other value ranges of the diameter of the eccentric portion 12 and the inner diameter coefficient of the outer ring 22 to correspond to determine the bearing lubrication coefficient and the speed coefficient of the eccentric shaft 10.

[0064] It should be noted that in Figure 4 In the embodiment, the value of the speed coefficient R of the eccentric shaft 10 may be positively correlated with the speed of the eccentric shaft 10. The value of the speed coefficient R of the eccentric shaft 10 may increase as the speed of the eccentric shaft 10 increases.

[0065] exist Figure 5 In the embodiment, the value of the inner diameter coefficient D of the outer ring 22 may be positively correlated with the value of the inner diameter of the outer ring 22 , and the value of the inner diameter coefficient D of the outer ring 22 may increase as the inner diameter of the outer ring 22 increases.

[0066] In some embodiments, the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28 can be obtained by the following formula:

[0067] λ=R×D×M,

[0068] Among them, λ represents the specific thickness of the oil film, R represents the rotational speed coefficient of the eccentric shaft 10, D represents the inner diameter coefficient of the outer ring 22, and M represents the bearing lubrication coefficient.

[0069] In this way, the oil film thickness can be calculated.

[0070] Specifically, it can be seen from Table 1 that the oil film thickness can be calculated according to the formula λ=R×D×M. In one example, when the diameter of the eccentric portion 12 has a value range of 20≤d<30, the inner diameter coefficient of the outer ring 22 is 0.9, and the bearing lubrication coefficient is 0.51, combined with Figure 4 The speed of the eccentric shaft 10 can generally reach 1000r / min to 1400r / min, r / min is the unit of speed, and the value range of the speed coefficient of the eccentric shaft 10 can be obtained as 3≤d≤4.2, so the minimum oil film thickness ratio can be calculated as 1.3770 and the maximum oil film thickness ratio can be calculated as 1.9278.

[0071] In another example, when the diameter of the eccentric portion 12 has a value range of 30≤d<40, the inner diameter coefficient of the outer ring 22 is 1.1, and the bearing lubrication coefficient is 0.51, Figure 4 The speed of the eccentric shaft 10 can generally reach 1000r / min to 1400r / min, r / min is the unit of speed, and the value range of the speed coefficient of the eccentric shaft 10 can be obtained as 3≤d≤4.2, so the minimum oil film thickness ratio can be calculated as 1.6830 and the maximum oil film thickness ratio can be calculated as 2.3562.

[0072] In another example, when the diameter of the eccentric portion 12 has a value interval of 40≤d<50, the inner diameter coefficient of the outer ring 22 is 1.35, and the bearing lubrication coefficient is 0.51, Figure 4 The speed of the eccentric shaft 10 can generally reach 1000r / min to 1400r / min, r / min is the unit of speed. The value range of the speed coefficient of the eccentric shaft 10 can be obtained as 3≤d≤4.2, so the minimum oil film thickness ratio can be calculated as 2.0655 and the maximum oil film thickness ratio can be calculated as 3.3737.

[0073] In another example, when the diameter of the eccentric portion 12 has a value interval of 50≤d<60, the inner diameter coefficient of the outer ring 22 is 1.6, and the bearing lubrication coefficient is 0.51, Figure 4 The speed of the eccentric shaft 10 can generally reach 1000r / min to 1400r / min, r / min is the unit of speed, and the value range of the speed coefficient of the eccentric shaft 10 can be obtained as 3≤d≤4.2, so the minimum oil film thickness ratio can be calculated as 2.4880 and the maximum oil film thickness ratio can be calculated as 3.9984.

[0074] Please combine Figure 6 In some embodiments, the bearing lubrication coefficient is obtained by the following formula:

[0075] M=T×A,

[0076] Among them, M represents the bearing lubrication coefficient, T represents the bearing type coefficient, and A represents the lubricant viscosity coefficient.

[0077] In this way, the bearing lubrication coefficient can be obtained.

[0078] Specifically, in Figure 6 In the embodiment, the magnitude of the lubricant viscosity coefficient may be positively correlated with the lubricant viscosity. The magnitude of the lubricant viscosity coefficient may increase as the lubricant viscosity increases. The bearing type coefficient is related to the bearing type. For example, the bearing type coefficient of the ball bearing is 1.5, the bearing type coefficient of the needle bearing 20 is 1, the bearing type coefficient of the tapered roller bearing is 1.1, and the bearing type coefficient of the self-aligning bearing is 0.8. In one embodiment, when the bearing type coefficient of the needle bearing 20 is 1 and the lubricant viscosity coefficient is 0.51, the bearing lubrication coefficient of the needle bearing 20 can be calculated to be 0.51.

[0079] In some implementations, the first preset range is [0.5, 4].

[0080] In this way, the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 is within a preset range, which is beneficial to the service life of the bearing.

[0081] Specifically, the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 is within the preset range [0.5, 4], which allows the needle roller bearing 20 to better match the eccentric portion 12, thereby reducing the wear of the needle roller bearing 20 and the eccentric portion 12 and increasing the service life of the bearing.

[0082] In one example, the values ​​in the preset range may be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, and other values ​​between 0.5 and 4.0.

[0083] In certain embodiments, the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28 is calculated by the oil film thickness and the composite surface roughness;

[0084] The oil film thickness is the thickness of the oil film between the eccentric portion 12 and the needle roller 28. The composite surface roughness corresponds to the surface roughness of the outer side wall of the eccentric portion 12 and the surface roughness of the outer side wall of the needle roller 28.

[0085] In this way, the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28 can be calculated.

[0086] Specifically, the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28 can be calculated according to the following formula:

[0087] λ=h / σ,

[0088] Among them, λ represents the specific thickness of the oil film, h represents the thickness of the oil film, and σ represents the synthetic surface roughness. That is, the specific thickness of the oil film between the eccentric portion 12 and the needle roller 28 can be calculated by the oil film thickness and the synthetic surface roughness. In addition, the oil film thickness in this embodiment can be the EHL (Elasto-hydrodynamic Lubrication) oil film thickness.

[0089] The synthetic surface roughness can be calculated according to the following formula:

[0090]

[0091] Here, σ may represent the combined surface roughness, σ1 may represent the surface roughness of the outer wall of the eccentric portion 12 , and σ2 may represent the surface roughness of the outer wall of the needle roller 28 .

[0092] As can be seen from Table 1, when the oil film thickness ratio ranges from 1.3770 to 3.9984, it can be the normal use range of the bearing. The oil film thickness in the reducer is usually less than 1 micron, so to ensure the above oil film thickness ratio, the roughness of the contact surface needs to be limited. In one embodiment, 1.3770≤λ≤3.9984 is substituted into the formula λ=h / σ to calculate the range of σ, and then the range of σ is substituted into the formula Finally, the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 can be calculated.

[0093] In some implementations, the second preset range is [1.3770, 3.9984].

[0094] In this way, the first preset range can be determined according to the optimal oil film thickness ratio.

[0095] Specifically, in one example, the values ​​of the second preset range may be 1.3770, 1.3771, 1.3772, 1.3773, 1.3774, 1.3775, 1.3776, 1.3778, 1.3779, 1.3780, 1.4700, 1.4770, 1.5770, 1.6770, 1.8770, 1.9770, 2.0770, 2.1770, 2.2770, 2.3770, 2.4770, 2.5770, 2.6770, 2.7770, 2.8770, 2.9770, 3.9970, 3.9980, 3.9981, 3.9982, 3.9983, 3.9984, and others between 1.3770 and 3.9984.

[0096] In some embodiments, the preset coefficients further include an oil film thickness compensation coefficient. The oil film thickness compensation coefficient is used to compensate for the deviation of the oil film thickness between the eccentric portion 12 and the needle roller 28. The value range of the oil film thickness compensation coefficient is [0.5, 0.7].

[0097] In this way, the oil film thickness can be further determined.

[0098] Specifically, in one embodiment, the oil film thickness compensation coefficient may be related to the oil film thickness. The oil film thickness compensation coefficient may be determined by the size of the oil film thickness. In one example, the value of the oil film thickness compensation coefficient may be 0.5, 0.6, 0.7, and other values ​​between 0.5 and 0.7.

[0099] Please refer to Figure 1 A reduction device 200 according to an embodiment of the present invention includes a transmission assembly 100 according to any one of the above embodiments.

[0100] In the above-mentioned reduction device 200, the first preset range is determined by the relative thickness of the oil film between the eccentric part 12 and the needle roller 28. The ratio of the surface roughness of the outer wall of the eccentric part 12 to the surface roughness of the outer wall of the needle roller 28 is within the first preset range, which is beneficial to improve the matching degree between the needle roller bearing 20 and the eccentric part 12, thereby reducing the wear of the needle roller bearing 20 and the eccentric part 12 and improving the service life of the bearing.

[0101] Specifically, the reduction device 200 includes a cycloid transmission reducer. In one embodiment, the first preset range is determined by the relative thickness of the oil film between the eccentric portion 12 and the needle roller 28, and the ratio of the surface roughness of the outer wall of the eccentric portion 12 to the surface roughness of the outer wall of the needle roller 28 is within the first preset range, which is conducive to improving the matching degree between the needle roller bearing 20 and the eccentric portion 12, thereby reducing the wear of the needle roller bearing 20 and the eccentric portion 12 and improving the service life of the bearing.

[0102] In addition, combined Figure 1 and Figure 7 The transmission assembly 100 further includes a cycloidal wheel 30. The cycloidal wheel 30 may be shaped like a disk. Three eccentric holes 32 may be provided on the end surface of the cycloidal wheel 30. The eccentric holes 32 may be in the shape of circular holes. The three eccentric holes 32 may be evenly arranged on the end surface of the cycloidal wheel 30 along the edge of the cycloidal wheel 30. In one embodiment, the needle bearing 20 may be inserted into the eccentric hole 32. The needle roller 28 may abut against the hole wall of the eccentric hole 32.

[0103] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0104] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A transmission assembly, characterized in that: The transmission assembly comprises: An eccentric shaft, wherein the eccentric shaft comprises a shaft body and an eccentric portion, wherein the eccentric portion is connected to the shaft body, and an axis of the eccentric portion is parallel to an axis of the shaft body; A needle roller bearing, the needle roller bearing comprising an outer ring and needle rollers, at least two needle rollers are arranged around the axis of the outer ring and rotatably connected to the outer ring, the eccentric portion passes through the outer ring, and the outer side wall of the eccentric portion abuts against the outer side wall of the needle rollers; The transmission assembly is configured so that the ratio of the surface roughness of the outer wall of the eccentric portion to the surface roughness of the outer wall of the needle roller is within a first preset range, and the first preset range can be determined by the specific thickness of the oil film between the eccentric portion and the needle roller.

2. The transmission assembly according to claim 1, characterized in that: The transmission assembly is configured so that the oil film specific thickness is within a second preset range, and the second preset range can be determined according to a preset coefficient and a value interval of the diameter of the eccentric portion.

3. The transmission assembly according to claim 2, characterized in that: The preset coefficients include an eccentric shaft speed coefficient, an outer ring inner diameter coefficient and a bearing lubrication coefficient. The eccentric shaft speed coefficient corresponds to the speed of the eccentric shaft, and each different range of values ​​for the diameter of the eccentric portion has a corresponding inner diameter coefficient of the outer ring.

4. The transmission assembly according to claim 3, characterized in that: The specific thickness of the oil film between the eccentric portion and the needle roller can be obtained by the following formula: λ=R×D×M, Wherein, λ represents the specific thickness of the oil film, R represents the rotation speed coefficient of the eccentric shaft, D represents the inner diameter coefficient of the outer ring, and M represents the bearing lubrication coefficient.

5. The transmission assembly according to claim 4, characterized in that: The bearing lubrication coefficient is obtained by the following formula: M=T×A, Wherein, M represents the bearing lubrication coefficient, T represents the bearing type coefficient, and A represents the lubricant viscosity coefficient.

6. The transmission assembly according to claim 4, characterized in that: The specific thickness of the oil film between the eccentric portion and the needle roller is calculated by the oil film thickness and the synthetic surface roughness; The oil film thickness is the thickness of the oil film between the eccentric portion and the needle roller, and the composite surface roughness corresponds to the surface roughness of the outer wall of the eccentric portion and the surface roughness of the outer wall of the needle roller.

7. The transmission assembly according to claim 1, characterized in that: The first preset range is [0.5, 4].

8. The transmission assembly according to claim 2, characterized in that: The second preset range is [1.3770, 3.9984].

9. The transmission assembly according to any one of claims 1 to 8, characterized in that: The preset coefficient also includes the oil film thickness compensation coefficient, which is used to compensate for the deviation of the oil film thickness between the eccentric part and the needle roller; The value range of the oil film thickness compensation coefficient is [0.5, 0.7].

10. A deceleration device, characterized in that: Comprising the transmission assembly according to any one of claims 1 to 9.

Images