A stop structure, a speed reducer, a transmission system and a helicopter

Abstract

The application discloses a stop structure, a speed reducer, a transmission system and a helicopter, wherein the stop structure comprises a gear shaft provided with a first shaft shoulder and a second shaft shoulder in sequence along an axial direction; the gear shaft is provided with a first bearing and a second bearing in interference fit; the second bearing is arranged on the right side of the second shaft shoulder along the axial direction, and one end of the second bearing, which is away from the first bearing along the axial direction, is abutted and fitted by a limiting mechanism for axial limiting; a spacing sleeve is arranged between the first shaft shoulder and the second shaft shoulder along the axial direction, and the spacing sleeve is arranged on the outside of the gear shaft in clearance fit; the two ends of the spacing sleeve along the axial direction are respectively abutted on one end of the first bearing and the second bearing, which are mutually facing, so as to tightly abut one end of the first bearing, which is away from the spacing sleeve, on the first shaft shoulder. The application further improves the fixing of the inner ring of the first bearing and the inner ring of the second bearing along the circumferential direction and the axial direction between the gear shaft without increasing the interference amount of the first bearing and the second bearing with the gear shaft, and improves the overhaul interval capacity of the speed reducer.

Description

Technical Field

[0001] This invention relates to the field of aviation transmission system technology, specifically to a stop structure, a speed reducer, a transmission system, and a helicopter. Background Technology

[0002] The gearbox is an important component of the helicopter transmission system, and its performance directly affects the performance of the helicopter. In the gearbox gear shaft support structure, if the transmitted power is small, in order to simplify the structure, reduce weight and improve reliability, some bearing inner rings and gear shaft journals can be directly used with an interference fit to ensure that there is no relative rotation and wear between the bearing inner ring and the gear shaft journal.

[0003] As helicopters become increasingly advanced, their performance requirements rise, necessitating higher power transmission from the gearboxes in the transmission system. Current technology addresses this by increasing the interference fit between the bearing inner ring and the gear shaft journal to mitigate relative rotation and fretting wear. However, this increased interference fit leads to increased circumferential stress on the bearing inner ring, reducing its lifespan. Furthermore, excessive interference fit during bearing disassembly can cause scoring between the inner ring and the gear shaft journal. Even with increased interference fit, circumferential and axial fixation between the inner ring and the gear shaft journal cannot be guaranteed. This results in relative rotation and axial movement during operation, causing severe wear and failure of components. Consequently, the overall overhaul interval capability of the gearbox is affected, potentially leading to serious delays in model development. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the gear shaft support structure of the prior art that uses the increase of the interference fit between the inner ring of the bearing and the journal of the gear shaft to overcome the relative rotation and fretting wear between the inner ring of the bearing and the journal of the gear shaft, which leads to a reduction in the overhaul interval capability of the reducer. The present invention provides a stop structure, a reducer, a transmission system and a helicopter.

[0005] According to a first aspect of the present invention, a stop structure is applied to a gear shaft support structure of a reducer, the stop structure comprising:

[0006] A gear shaft, wherein the gear shaft is configured as a stepped shaft, and a first shoulder and a second shoulder are sequentially provided on the gear shaft from left to right along its axial direction;

[0007] A bearing housing, which is sleeved on the outside of the gear shaft;

[0008] A first bearing is disposed between the gear shaft and the bearing housing, wherein the inner ring of the first bearing is interference-fitted with the gear shaft, and one end of the first bearing abuts against the first shaft shoulder along the axial direction.

[0009] The second bearing is disposed between the gear shaft and the bearing housing, and the inner ring of the second bearing is interference-fitted with the gear shaft; the second bearing is disposed on the right side of the second shaft shoulder along the axial direction, and the end of the second bearing opposite to the first bearing along the axial direction is abutted and fitted by a limiting mechanism for axial limiting;

[0010] A spacer sleeve is axially disposed between the first shoulder and the second shoulder, and the spacer sleeve is fitted with a clearance fit around the gear shaft; the two ends of the spacer sleeve axially abut against the opposite ends of the first bearing and the second bearing, respectively, so as to press the inner ring of the first bearing tightly against the first shoulder.

[0011] According to a stopping structure of the present invention, at least the following technical effects are achieved: 1. By providing an axial spacer sleeve between the first bearing and the second bearing, and the spacer sleeve being fitted with a clearance fit outside the gear shaft, after the limiting mechanism is installed on the gear shaft and axially abuts against the inner ring of the second bearing, the limiting mechanism applies an axial tightening force, causing the second bearing to be pressed against the spacer sleeve to generate contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer sleeve, the axial tightening force applied by the limiting mechanism to the second bearing is also applied to the first bearing, thereby causing the first bearing to be pressed against the first shaft shoulder to generate contact friction. The contact friction between the first bearing and the first shaft shoulder, and the contact friction between the second bearing and the spacer sleeve... The friction force effectively prevents relative rotation and wear between the inner rings of the first and second bearings and the gear shaft. The spacer sleeve, tightly fitted between the first and second bearings, ensures improved circumferential and axial fixation of the inner rings of the first and second bearings and the gear shaft without increasing the interference fit. This effectively prevents relative rotation and axial movement between the inner rings of the first and second bearings and the gear shaft during use, thus avoiding component failure due to severe wear. It also improves the reducer's overhaul interval capability, prevents the accumulation of large amounts of wear debris inside the reducer, improves lubricant cleanliness, and extends the service life of gears and bearings. 2. This stop structure only requires adding a spacer sleeve to the gear shaft in the original reducer gear shaft support structure with a clearance fit. This spacer sleeve presses against the end face of the inner ring of the first bearing, resulting in greater contact friction between the first bearing and the first shaft shoulder. This improves the reducer's overhaul interval capability. The overall added weight is light, and the load on the entire reducer gear shaft support structure is negligible. Furthermore, the spacer sleeve and gear shaft have a clearance fit, making assembly and disassembly easy. 3. This stop structure can meet the usage requirements of reducers in transmission systems with high power transmission without increasing the interference fit between the inner ring of the first bearing and the inner ring of the second bearing and the gear shaft. This avoids damage to the bearing inner ring and gear shaft journal during bearing disassembly and facilitates assembly and disassembly. 4. A spacer sleeve is added between the first bearing and the second bearing. The inner ring of the first bearing fits against the first shaft shoulder, and the inner ring of the first bearing, the spacer sleeve, and the inner ring of the second bearing are all in a compressed state. This makes the part of the gear shaft located between the first shaft shoulder and the second shaft shoulder structurally stronger under compressive load, improves the radial stiffness of the gear shaft, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer.

[0012] Preferably, the end of the spacer sleeve facing the second bearing is folded radially toward the axis to form an abutment portion; the abutment portion is disposed between the inner ring of the second bearing and the second shoulder.

[0013] Preferably, the gear shaft is provided with a first connecting part, a second connecting part, and a third connecting part from left to right along its axial direction. The shaft diameters of the first connecting part, the second connecting part, and the third connecting part decrease in sequence. The connection between the first connecting part and the second connecting part is set as the first shaft shoulder, and the connection between the second connecting part and the third connecting part is set as the second shaft shoulder. The spacer sleeve is clearance-fitted with the second connecting part.

[0014] Preferably, a fourth connecting portion is provided between the second connecting portion and the third connecting portion, the shaft diameter of the fourth connecting portion being larger than the shaft diameter of the third connecting portion and smaller than the shaft diameter of the second connecting portion; a third shoulder is provided between the second connecting portion and the fourth connecting portion, the axial distance between the first shoulder and the third shoulder being no greater than the axial length of the inner ring of the first bearing; the spacer sleeve is clearance-fitted with the fourth connecting portion; the thickness of the spacer sleeve is greater than the difference in shaft diameter between the second connecting portion and the fourth connecting portion.

[0015] Preferably, the end of the spacer sleeve facing the first bearing is folded radially away from the axis to form a boss, and the boss abuts against and fits against the inner ring of the first bearing.

[0016] Preferably, the limiting mechanism includes a flange that is axially locked onto the gear shaft by a locking nut, the flange abutting against the inner ring of the second bearing at one end axially toward the second bearing to apply an axial tightening force to the second bearing.

[0017] Preferably, a fifth connecting part is provided at the end of the third connecting part away from the second connecting part, and the shaft diameter of the fifth connecting part is smaller than that of the third connecting part; the flange and the fifth connecting part are connected by a spline to transmit torque.

[0018] According to a second aspect of the present invention, a speed reducer employs the stop structure provided in the first aspect described above.

[0019] According to the present invention, a speed reducer has at least the following technical effects:

[0020] 1. By providing an axial spacer sleeve between the first bearing and the second bearing, with the spacer sleeve fitted off the gear shaft with a clearance fit, after the limiting mechanism is installed on the gear shaft and axially abuts against the inner ring of the second bearing, the limiting mechanism applies an axial clamping force, causing the second bearing to be pressed against the spacer sleeve, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer sleeve, the axial clamping force applied to the second bearing by the limiting mechanism is also applied to the first bearing, thereby pressing the first bearing against the first shaft shoulder, generating contact friction. The contact friction between the first bearing and the first shaft shoulder, and the contact friction between the second bearing and the spacer sleeve, effectively prevent the inner ring of the first bearing from contacting the first bearing. The inner rings of the two bearings rotate relative to each other and wear on the gear shaft. The spacer sleeve is tightly fitted between the first and second bearings, ensuring improved circumferential and axial fixation of the inner rings of the first and second bearings to the gear shaft without increasing the interference fit. This effectively prevents relative rotation and axial movement between the inner rings of the first and second bearings and the gear shaft during use, thus avoiding component failure due to severe wear. It also improves the reducer's overhaul interval capability, prevents the accumulation of large amounts of wear debris inside the reducer, improves lubricating oil cleanliness, and extends the service life of gears and bearings, thereby increasing the overall service life of the reducer. 2. This reducer only adds a spacer sleeve to the gear shaft in the original reducer gear shaft support structure with a clearance fit. This spacer sleeve presses the end face of the inner ring of the first bearing, resulting in greater contact friction between the first bearing and the first shaft shoulder. This improves the reducer's overhaul interval capability. The overall added weight is light, and the load on the entire reducer gear shaft support structure is negligible. Furthermore, the spacer sleeve and gear shaft have a clearance fit, making assembly and disassembly easy. 3. This reducer can meet the requirements of reducers in transmission systems with high power transmission without increasing the interference fit between the inner ring of the first bearing and the inner ring of the second bearing and the gear shaft. This avoids damage to the bearing inner ring and gear shaft journal during bearing disassembly and facilitates assembly and disassembly. 4. A spacer sleeve is added between the first bearing and the second bearing. The inner ring of the first bearing fits against the first shaft shoulder, and the inner ring of the first bearing, the spacer sleeve, and the inner ring of the second bearing are all in a compressed state. This makes the part of the gear shaft located between the first shaft shoulder and the second shaft shoulder structurally stronger under compressive load, improves the radial stiffness of the gear shaft, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer.

[0021] According to a third aspect of the present invention, a transmission system includes the stop structure provided in the first aspect above.

[0022] According to a transmission system of the present invention, at least the following technical effects are achieved:

[0023] 1. By providing an axial spacer sleeve between the first and second bearings, with the spacer sleeve fitted over the gear shaft, after the limiting mechanism is installed on the gear shaft and axially abuts against the inner ring of the second bearing, the limiting mechanism applies an axial clamping force, causing the second bearing to be pressed against the spacer sleeve, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer sleeve, the axial clamping force applied to the second bearing by the limiting mechanism is also applied to the first bearing, thus pressing the first bearing against the first shaft shoulder, generating contact friction. The contact friction between the first bearing and the first shaft shoulder, and the contact friction between the second bearing and the spacer sleeve, effectively prevent the inner ring of the first bearing from contacting the second bearing. The inner ring of the gear and the gear shaft rotate relative to each other and wears. The spacer sleeve is tightly fitted between the first and second bearings, ensuring improved circumferential and axial fixation of the inner rings of the first and second bearings to the gear shaft without increasing the interference fit. This effectively prevents relative rotation and axial movement between the inner rings of the first and second bearings and the gear shaft during use, thus avoiding component failure due to severe wear. It improves the reducer's overhaul interval capability, prevents the accumulation of large amounts of wear debris inside the reducer, improves lubricating oil cleanliness, and extends the service life of gears and bearings, thereby increasing the service life of the reducer and transmission system. 2. This transmission system only requires adding a spacer sleeve to the gear shaft in the original reducer gear shaft support structure with a clearance fit. This spacer sleeve presses against the end face of the inner ring of the first bearing, resulting in greater contact friction between the first bearing and the first shaft shoulder. This improves the reducer's overhaul interval capability. The overall added weight is light, and the load on the entire reducer gear shaft support structure is negligible. Furthermore, the spacer sleeve has a clearance fit with the gear shaft, making it easy to assemble and disassemble. 3. This transmission system can meet the requirements of reducers in transmission systems with high power transmission without increasing the interference fit between the inner ring of the first bearing and the inner ring of the second bearing and the gear shaft. This avoids damage to the bearing inner ring and gear shaft journal during bearing disassembly and facilitates assembly and disassembly. 4. A spacer sleeve is added between the first bearing and the second bearing. The inner ring of the first bearing fits against the first shaft shoulder, and the inner ring of the first bearing, the spacer sleeve, and the inner ring of the second bearing are all in a compressed state. This makes the part of the gear shaft located between the first shaft shoulder and the second shaft shoulder structurally stronger under compressive load, improves the radial stiffness of the gear shaft, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer and transmission system.

[0024] A helicopter according to a fourth aspect of the present invention includes the stop structure provided in the first aspect above.

[0025] A helicopter according to the present invention has at least the following technical effects:

[0026] 1. By providing an axial spacer sleeve between the first and second bearings, with the spacer sleeve fitted with a clearance fit outside the gear shaft, after the limiting mechanism is installed on the gear shaft and axially abuts against the inner ring of the second bearing, the limiting mechanism applies an axial clamping force, causing the second bearing to be pressed against the spacer sleeve, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer sleeve, the axial clamping force applied to the second bearing by the limiting mechanism is also applied to the first bearing, thereby pressing the first bearing against the first shaft shoulder, generating contact friction. The contact friction between the first bearing and the first shaft shoulder, and the contact friction between the second bearing and the spacer sleeve, effectively prevent the inner ring of the first bearing from collapsing. The relative rotation and wear between the ring and the gear shaft, along with the spacer sleeve tightly fitted between the first and second bearings, ensures improved circumferential and axial fixation of the inner rings of the first and second bearings and the gear shaft without increasing the interference fit between them. This effectively prevents relative rotation and axial movement between the inner rings of the first and second bearings and the gear shaft during use, thus avoiding component failure due to severe wear. It also improves the reducer's overhaul interval capability, prevents the accumulation of large amounts of wear debris inside the reducer, improves lubricant cleanliness, and extends the service life of gears and bearings, thereby increasing the service life of the reducer, transmission system, and helicopter. 2. This helicopter only adds a spacer sleeve to the gear shaft in the existing reducer gear shaft support structure with a clearance fit. This spacer sleeve presses the end face of the inner ring of the first bearing, resulting in greater contact friction between the first bearing and the first shaft shoulder. This improves the reducer's overhaul interval capability. The overall added weight is light, and the load on the entire reducer gear shaft support structure is negligible. Furthermore, the spacer sleeve and gear shaft have a clearance fit, making assembly and disassembly easy. 3. This helicopter can meet the requirements of a high-power transmission system reducer without increasing the interference fit between the inner ring of the first bearing and the inner ring of the second bearing and the gear shaft. This avoids damage to the bearing inner ring and gear shaft journal during bearing removal and facilitates assembly and disassembly. 4. A spacer sleeve is added between the first bearing and the second bearing. The inner ring of the first bearing fits against the first shaft shoulder, and the inner ring of the first bearing, the spacer sleeve, and the inner ring of the second bearing are all in a compressed state. This strengthens the structure of the gear shaft located between the first shaft shoulder and the second shaft shoulder under compressive load, improves the radial stiffness of the gear shaft, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer, transmission system, and helicopter.

[0027] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a stop structure applied to a gear shaft support structure of a reducer according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A cross-sectional view of the spacer sleeve in the middle;

[0031] Figure 3 for Figure 1 A cross-sectional view of the intermediate gear shaft;

[0032] Figure 4 This is a distribution diagram of the relative slip between the gear shaft and the inner ring of the first bearing in the finite element simulation analysis of the stop structure applied to the gear shaft support structure of the reducer according to an embodiment of the present invention.

[0033] Figure 5 This is a diagram showing the contact pressure distribution between the gear shaft and the inner ring of the first bearing in the finite element simulation analysis of the stop structure applied to the gear shaft support structure of the reducer according to an embodiment of the present invention.

[0034] Figure 6 This is a diagram showing the frictional work distribution between the gear shaft and the inner ring of the first bearing in the finite element simulation analysis of the stop structure applied to the gear shaft support structure of the reducer according to an embodiment of the present invention.

[0035] Figure 7 This is a schematic diagram of the change curve of slip as a function of interference in the finite element simulation analysis of the stop structure applied to the gear shaft support structure of the reducer according to an embodiment of the present invention.

[0036] Figure 8 This is a schematic diagram of the contact pressure versus interference curve in the finite element simulation analysis of the stop structure applied to the gear shaft support structure of the reducer according to an embodiment of the present invention.

[0037] Figure 9 This is a schematic diagram showing the change of frictional work with interference in the finite element simulation analysis of the stop structure applied to the gear shaft support structure of the reducer according to an embodiment of the present invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1-Gear shaft, 11-First shoulder, 12-Second shoulder, 13-First connecting part, 14-Second connecting part, 15-Third connecting part, 16-Fourth connecting part, 17-Third shoulder, 18-Fifth connecting part;

[0040] 2-Bearing housing;

[0041] 3-First bearing;

[0042] 4-Second bearing;

[0043] 5-spacer sleeve, 51-abutment part, 52-protrusion;

[0044] 6- Lock nut;

[0045] 7-Flange. Detailed Implementation

[0046] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for 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. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[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 can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] Example 1

[0051] like Figures 1 to 3 The diagram shows a stop structure provided in this embodiment, applied to a gear shaft support structure of a reducer. The stop structure includes a gear shaft 1, a bearing housing 2, a first bearing 3, a second bearing 4, and a spacer sleeve 5. The gear shaft 1 is configured as a stepped shaft, and a first shoulder 11 and a second shoulder 12 are sequentially provided on the gear shaft 1 from left to right along the axial direction of the gear shaft 1. The bearing housing 2 is sleeved on the gear shaft 1. The first bearing 3 is disposed between the gear shaft 1 and the bearing housing 2, and the inner ring of the first bearing 3 is interference-fitted with the gear shaft 1, with one end abutting against the first shoulder 11 along the axial direction. The second bearing 4 is disposed between the gear shaft 1 and the bearing housing. Between the first and second shaft shoulders 11 and 2, the inner ring of the second bearing 4 is press-fitted with the gear shaft 1; the second bearing 4 is located on the right side of the second shaft shoulder 12 along the axial direction, and the end of the second bearing 4 facing away from the first bearing 3 along the axial direction is abutted and pressed against by a limiting mechanism for axial tightening and limiting; the spacer sleeve 5 is axially disposed between the first shaft shoulder 11 and the second shaft shoulder 12, and the spacer sleeve 5 is clearance-fitted onto the outside of the gear shaft 1; the two ends of the spacer sleeve 5 along the axial direction are respectively abutted against the inner rings of the first bearing 3 and the inner rings of the second bearing 4 at their respective facing ends, so as to press the end of the inner ring of the first bearing 3 facing away from the spacer sleeve 5 against the first shaft shoulder 11. It can be understood that the axial direction mentioned in this embodiment refers to Figure 1 The axial direction shown; the axial direction of the gear shaft 1 refers to the direction relative to the axis of rotation. Figure 1 The directions shown are parallel to the axial direction; the left and right directions described in this embodiment are parallel to... Figure 1 The axes are parallel and based on Figure 1 The following description is based on the perspective of the first bearing 3: the inner ring of the first bearing 3 refers to the inner ring portion of the first bearing 3, and the outer ring of the first bearing 3 refers to the outer ring portion of the first bearing 3; the inner ring of the second bearing 4 refers to the inner ring portion of the second bearing 4, and the outer ring of the second bearing 4 refers to the outer ring portion of the second bearing 4.

[0052] In this embodiment of the invention, a spacer sleeve 5 is axially disposed between the first bearing 3 and the second bearing 4, and the spacer sleeve 5 is fitted with a clearance fit around the gear shaft 1. After the limiting mechanism is installed on the gear shaft 1 and axially abuts against the inner ring of the second bearing 4, the limiting mechanism applies an axial tightening force, causing the second bearing 4 to be pressed against the spacer sleeve 5, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer sleeve 5, the axial tightening force applied to the second bearing 4 by the limiting mechanism is also applied to the first bearing 3, thereby causing the first bearing 3 to be pressed against the first shaft shoulder 11, generating contact friction. The contact friction between the first bearing 3 and the first shaft shoulder 11, and the contact friction between the second bearing 4 and the spacer sleeve 5, can effectively prevent the inner ring of the first bearing 3 and the second bearing 4 from colliding. The inner ring rotates relative to the gear shaft 1, causing wear. The spacer sleeve 5 is pressed between the first bearing 3 and the second bearing 4, ensuring improved circumferential and axial fixation of the inner rings of the first bearing 3 and the second bearing 4 to the gear shaft 1 without increasing the interference fit. This effectively prevents relative rotation and axial movement between the inner rings of the first bearing 3 and the second bearing 4 and the gear shaft 1 during use, thus avoiding component failure due to severe wear. It improves the reducer's overhaul interval capability (tested to increase it by 20% to 30%), avoids the accumulation of large amounts of wear debris inside the reducer, improves lubricant cleanliness, and extends the service life of gears and bearings. The stop structure in this embodiment only adds a spacer sleeve 5 to the gear shaft 1 in the original gear shaft support structure of the reducer with a clearance fit. This presses the inner ring of the first bearing 3 with its end face, resulting in greater contact friction between the first bearing 3 and the first shaft shoulder 11. This not only better transmits the bearing force generated by the bevel gear mounted on the gear shaft 1 to the bearing housing 2 through the first bearing 3, but also improves the overhaul interval capability of the reducer. At the same time, the overall weight increase is light, and the type, size, and support position of the first bearing 3 and the second bearing 4 are not affected by the addition of the spacer sleeve 5. Since the meshing force (and its additional bending moment) transmitted by the first bearing 3 and the second bearing 4 remains unchanged, the contact form between the inner ring of the second bearing 4 and the gear shaft 1 and the spacer sleeve 5 remains unchanged (that is, the fit between the two ends of the inner ring of the second bearing 4 along the axial direction and the magnitude of the load it bears do not change). Therefore, the load transmission between the inner ring of the second bearing 4 and the gear shaft 1 or the spacer sleeve 5, and between the inner ring of the second bearing 4 and the limiting mechanism remains unchanged. The adverse effects on the entire gear shaft support structure of the reducer are almost negligible. Moreover, the spacer sleeve 5 and the gear shaft 1 are clearance fit, which is easy to install and disassemble.The stop structure of this embodiment can meet the requirements of a reducer in a transmission system with a large power transmission capacity without increasing the interference fit between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1. This avoids damage to the inner ring of the bearing and the journal of the gear shaft 1 when disassembling the bearing, and facilitates assembly and disassembly. In this embodiment, a spacer sleeve 5 is added between the first bearing 3 and the second bearing 4. The inner ring of the first bearing 3 fits against the first shoulder 11, and the inner ring of the first bearing 3, the spacer sleeve 5, and the inner ring of the second bearing 4 are all in a compressed state. This strengthens the structure of the part of the gear shaft 1 located between the first shoulder 11 and the second shoulder 12 under compressive load (similar to increasing the wall thickness of the gear shaft 1 in the part where the spacer sleeve 5 is added), improves the radial stiffness of the gear shaft 1, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer. The stop structure of this embodiment adds a spacer sleeve 5 to the gear shaft 1 with a clearance fit. The spacer sleeve 5 is pressed between the inner ring of the first bearing 3 and the inner ring of the second bearing 4. Compared with the existing structure, even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, it is still not possible to guarantee the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1. The stop structure of this embodiment, after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, can effectively reduce the slippage of the inner ring of the first bearing 3 relative to the journal of the gear shaft 1 and increase the contact pressure between the first bearing 3 and the gear shaft 1. It can effectively avoid the phenomenon that the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1 cannot be guaranteed even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1.

[0053] It should be noted that in this embodiment, the interference fit between the inner ring of the first bearing 3 and the gear shaft 1 adopts a common interference fit situation in the prior art. Currently, the interference amount is generally designed to be 0.05 mm to 0.08 mm. This installation method can reduce the fretting wear caused by the relative movement between the bearing inner diameter and the shaft outer diameter (i.e., the journal). The interference fit between the bearing inner ring and the journal will cause tensile stress in the circumferential direction of the bearing inner ring, which is called circumferential stress (HOOPSTRESS). When designing the bearing fit, the interference should not be too large, so as to avoid the bearing raceway developing pits or peeling, which will cause vibration in gear meshing, deformation of hollow shafts, etc. After the bearing has been working for a long time, the excessive circumferential stress will cause the bearing inner ring or outer ring to break. In addition, if the interference amount is too large, it will make the bearing difficult to disassemble. When disassembling the bearing inner ring, the inner ring of the bearing is prone to scoring between the bearing inner ring and the journal of the gear shaft 1. The interference fit between the inner ring of the second bearing 4 and the gear shaft 1 is generally designed to be 0.025 mm to 0.05 mm. This interference fit can ensure that there is no relative rotation and wear between the inner ring of the second bearing 4 and the gear shaft 1, and can also prevent the interference fit from being too large, which would increase the circumferential stress between the inner ring of the second bearing 4 and the gear shaft 1, making it easy for the inner ring of the second bearing 4 and the gear shaft 1 to be strained when disassembling the inner ring of the second bearing 4.

[0054] Specifically, the gap between the spacer sleeve 5 and the gear shaft 1 is set to 0.03 mm to 0.05 mm. After testing, this gap range can ensure that the spacer sleeve 5 and the gear shaft 1 have a certain degree of coaxiality during operation, and that the two ends of the spacer sleeve 5 along the axial direction are well fitted with the end faces of the inner ring of the first bearing 3 and the inner ring of the second bearing 4 respectively (without deviation). It can also ensure convenient operation during installation and disassembly.

[0055] like Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the spacer sleeve 5 is folded radially toward the axis at one end facing the second bearing 4 to form an abutment portion 51; the abutment portion 51 is disposed between the inner ring of the second bearing 4 and the second shoulder 12. The abutment portion 51 can, on the one hand, increase the contact area with the inner ring of the second bearing 4, increasing the contact friction between the inner ring of the second bearing 4 and the abutment portion 51, thereby more effectively preventing relative rotation and wear between the inner ring of the second bearing 4 and the gear shaft 1; on the other hand, the abutment portion 51 can also serve as a positioning element, ensuring that when the spacer sleeve 5 is moved relative to the gear shaft 1 to the position where the abutment portion 51 abuts against the second shoulder 12, the other end of the spacer sleeve 5 is pressed tightly against the inner ring of the first bearing 3, thereby ensuring that the inner ring of the first bearing 3 and the first shoulder 11 abut against each other and generate a large contact friction force, thus effectively preventing relative rotation and wear between the inner ring of the first bearing 3 and the gear shaft 1.

[0056] like Figure 1 and Figure 3 As shown, in some embodiments of the present invention, the gear shaft 1 is provided with a first connecting portion 13, a second connecting portion 14, and a third connecting portion 15 sequentially from left to right along the axial direction of the gear shaft 1. The shaft diameters of the first connecting portion 13, the second connecting portion 14, and the third connecting portion 15 decrease sequentially. The connection point between the first connecting portion 13 and the second connecting portion 14 is set as the first shaft shoulder 11, and the connection point between the second connecting portion 14 and the third connecting portion 15 is set as the second shaft shoulder 12. The spacer sleeve 5 is clearance-fitted with the second connecting portion 14. By setting the gear shaft 1 as a stepped shaft with three steps, it is easier to process and stress concentration is reduced, further increasing the structural strength of the gear shaft 1.

[0057] Considering that the spacer sleeve 5 needs to abut and fit against the inner rings of the first bearing 3 and the second bearing 4 at both ends along the axial direction, in order to ensure that the contact area between the spacer sleeve 5 and the inner rings of the first bearing 3 and the second bearing 4 after installation is large enough, thereby ensuring that the magnitude of the contact friction force generated between the inner ring of the second bearing 4 and the spacer sleeve 5, and between the inner ring of the first bearing 3 and the first shoulder 11, can meet the requirements of preventing relative rotation and wear between the inner ring of the second bearing 4 and the gear shaft 1, and between the inner ring of the first bearing 3 and the gear shaft 1; Figure 1 and Figure 3As shown, in some embodiments of the present invention, a fourth connecting portion 16 is provided between the second connecting portion 14 and the third connecting portion 15. The shaft diameter of the fourth connecting portion 16 is larger than that of the third connecting portion 15 and smaller than that of the second connecting portion 14. The connection between the fourth connecting portion 16 and the third connecting portion 15 is provided as a second shoulder 12, and a third shoulder 17 is provided between the second connecting portion 14 and the fourth connecting portion 16. The axial distance between the first shoulder 11 and the third shoulder 17 is not greater than the axial length of the inner ring of the first bearing 3. The spacer sleeve 5 is clearance-fitted with the fourth connecting portion 16. The thickness of the spacer sleeve 5 is greater than the difference in shaft diameter between the second connecting portion 14 and the fourth connecting portion 16. By setting the axial length of the inner ring of the first bearing 3 to be less than or equal to the axial distance between the first shoulder 11 and the third shoulder 17, it can be ensured that the spacer sleeve 5, which is clearance-fitted on the fourth connecting part 16, can apply an axial clamping force to the inner ring of the first bearing 3 under the clamping action of the inner ring of the second bearing 4. This ensures that the inner ring of the first bearing 3 fits against the first shoulder 11 to generate a large contact friction force, and that the inner ring of the first bearing 3, the spacer sleeve 5, and the inner ring of the second bearing 4 are all in a compressed state. This further ensures that the circumferential and axial fixing effect between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1 is further improved without increasing the interference fit between the first bearing 3 and the second bearing 4 and the gear shaft 1. This meets the usage requirements of the reducer in the transmission system with large power transmission and improves the overhaul interval capability of the reducer.

[0058] like Figure 1 and Figure 2 As shown, in some embodiments of the present invention, the end of the spacer sleeve 5 facing the first bearing 3 is folded radially away from the axis to form a boss 52, which abuts against and fits against the inner ring of the first bearing 3. The boss 52 can increase the contact area between the boss and the inner ring of the first bearing 3, thereby better transmitting the axial clamping force applied by the limiting mechanism to the inner ring of the first bearing 3, increasing the contact friction between the inner ring of the first bearing 3 and the first shoulder 11, and more effectively preventing relative rotation and wear between the inner ring of the first bearing 3 and the gear shaft 1, further improving the overhaul interval capability of the reducer.

[0059] like Figure 1In some embodiments of the present invention, the limiting mechanism includes a flange 7 axially locked onto the gear shaft 1 by a locking nut 6. The flange 7 abuts against the inner ring of the second bearing 4 at one end axially toward the second bearing 4. The flange 7 applies an axial tightening force by continuously tightening the locking nut 6, axially pressing the inner ring of the second bearing 4, the spacer 5, and the inner ring of the first bearing 3 together. This results in a large contact friction force between the inner ring of the first bearing 3 and the first shoulder 11, and between the inner ring of the second bearing 4 and the spacer 5. This ensures that the circumferential and axial fixing effect between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1 is further improved without increasing the interference fit between the first bearing 3 and the second bearing 4 and the gear shaft 1. This meets the usage requirements of the reducer in a transmission system with large power transmission and improves the overhaul interval capability of the reducer.

[0060] To prevent the flange 7 from undergoing axial displacement relative to the gear shaft 1 during use, which would prevent the locking nut 6 from providing axial clamping, in some embodiments of the present invention, a fifth connecting part 18 is provided at the end of the third connecting part 15 opposite to the second connecting part 14. The shaft diameter of the fifth connecting part 18 is smaller than that of the third connecting part 15. The flange 7 and the fifth connecting part 18 are connected by a spline to transmit torque. To further improve the positioning and assembly accuracy of the spline, specifically, cylindrical mating sections are provided at both ends of the spline along the axial direction, and mating inner holes matching the cylindrical mating sections are provided inside the flange 7 and on the outer peripheral surface of the fifth connecting part 18.

[0061] This invention also provides the following simulation analysis method to perform finite element simulation analysis on the stop structure of this embodiment, calculating the contact pressure (contact stress) and relative slippage corresponding to different interference fits between the inner ring of the first bearing 3 and the gear shaft 1 under a given transmission power, and combining the contact pressure (contact stress) and relative slippage into a comprehensive index "friction work" to assess the wear risk at the bearing; the specific steps are as follows:

[0062] Import the three-dimensional model of the stop structure composed of parts such as gear shaft 1, first bearing 3, and spacer sleeve 5 into ANSYS Workbench software (ANSYS's new generation of collaborative simulation integration platform). Use high-order hexahedral elements to mesh each part.

[0063] The contact surfaces of each part are set to frictional contact, and an initial interference fit is set between the inner ring of the first bearing 3 and the gear shaft 1.

[0064] Apply meshing force, preload, and other loads to the gear shaft assembly in the stop structure, and set axial and radial constraints;

[0065] Contact nonlinearity calculations were used to extract the relative slip and contact pressure (contact stress) between the inner ring of the first bearing 3 and the gear shaft 1. Specifically, the typical distribution of the relative slip between the gear shaft 1 and the inner ring of the first bearing 3 is shown below. Figure 4 As shown, the typical contact pressure (contact stress) distribution between the gear shaft 1 and the inner ring of the first bearing 3 is as follows: Figure 5 As shown;

[0066] The relative slip and contact pressure (contact stress) are processed and analyzed to synthesize frictional work, and the wear risk of gear shaft 1 is assessed by the magnitude of the frictional work; specifically, the typical frictional work distribution between gear shaft 1 and the inner ring of the first bearing 3 is as follows. Figure 6 As shown;

[0067] The ANSYS Workbench software was used to analyze the curves of slip, contact pressure (contact stress), and frictional work as a function of interference fit. Specifically, the curve of slip as a function of interference fit is shown below. Figure 7 As shown; the curve of contact pressure (contact stress) versus interference fit is as follows. Figure 8 As shown; the curve of frictional work changing with interference fit is as follows. Figure 9 As shown;

[0068] Table 1 shows the specific slip, contact pressure and friction work values ​​corresponding to different interference fits between the inner ring of the first bearing 3 and the gear shaft 1.

[0069] Table 1 shows the specific slip, contact pressure, and friction work values ​​corresponding to different interference fits.

[0070]

[0071] As shown in Table 1, the slip, contact pressure and friction work all change monotonically with the interference. The maximum slip decreases as the interference increases, the maximum contact pressure increases as the interference increases, and the maximum friction work increases as the interference increases.

[0072] In summary, the stop structure of this embodiment, by increasing the interference fit between the inner ring of the first bearing 3 and the gear shaft 1, can ensure the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1. This avoids the problem in existing technologies where, even after increasing the interference fit, the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1 cannot be guaranteed. The stop structure of this embodiment effectively prevents relative rotation and wear between the inner ring of the first bearing 3 and the gear shaft 1, improving the overhaul interval and service life of the reducer. Simultaneously, it meets the requirements of reducers in transmission systems with higher power transmission without significantly increasing the interference fit between the inner ring of the first bearing 3 and the gear shaft 1. Compared to existing technologies that simply increase the interference fit between the inner ring of the first bearing 3 and the gear shaft 1 to meet the requirements of reducers in transmission systems with higher power transmission, the stop structure of this embodiment effectively reduces the interference fit between the inner ring of the first bearing 3 and the gear shaft 1, reduces the circumferential stress of the inner ring of the first bearing 3, improves the service life of the first bearing 3, and facilitates assembly and disassembly.

[0073] It is understandable that the calculation method used in the above simulation analysis method is based on the algorithm embedded in the software.

[0074] It should be noted that the selection scheme of the stop structure of the present invention with or without the spacer sleeve 5 is explained as follows: 1. Rolling bearings are usually installed on the gear shaft 1 with an interference fit. This installation method can reduce the fretting wear caused by the relative movement between the bearing inner diameter and the journal. However, the interference fit between the bearing inner ring and the bearing will cause the bearing to generate tensile or compressive stress in the circumferential direction. This stress is called circumferential stress. 1. When designing the bearing fit, the interference should not be too large to avoid excessive circumferential stress in the bearing raceway, which could cause the inner or outer ring of the bearing to break. 2. For the roller bearing inner ring and gear shaft 1, a structure without spacer sleeve 5 or with spacer sleeve 5 can be used, depending on whether the friction generated by the interference can overcome the tendency of relative rotation between the bearing inner ring and the journal of gear shaft 1. 3. For the structure without spacer sleeve 5, the interference should be appropriately increased to ensure that there is no relative rotation or axial movement between the bearing inner ring and the journal of gear shaft 1. However, the interference should not be too large. In addition to considering the circumferential stress of the bearing inner ring caused by the interference, it should also be considered that the bearing disassembly process will not cause scratches on the mating cylindrical surface of gear shaft 1. 4. If the interference fit cannot meet the design and usage requirements, a stop structure with spacer sleeve 5 can be selected according to the embodiment of the present invention. The bearing inner ring is pressed by spacer sleeve 5 and locking nut 6, and a small interference fit is maintained between the bearing inner ring and the journal.

[0075] Example 2

[0076] This embodiment provides a speed reducer, including the stop structure described in Embodiment 1. The speed reducer of this embodiment has a spacer sleeve 5 axially disposed between the first bearing 3 and the second bearing 4, and the spacer sleeve 5 is fitted with a clearance fit around the gear shaft 1. After the limiting mechanism is installed on the gear shaft 1 and axially abuts against the inner ring of the second bearing 4, the limiting mechanism applies an axial clamping force, causing the second bearing 4 to be pressed against the spacer sleeve 5, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer sleeve 5, the axial clamping force applied to the second bearing 4 by the limiting mechanism is also applied to the first bearing 3, thereby causing the first bearing 3 to be pressed against the first shaft shoulder 11, generating contact friction. The contact friction between the first bearing 3 and the first shaft shoulder 11, and the contact friction between the second bearing 4 and the spacer sleeve 5, can effectively prevent the first bearing... The inner ring of bearing 3 and the inner ring of bearing 4 rotate relative to each other and wears on the gear shaft 1. The spacer sleeve 5 is tightly fitted between bearing 3 and bearing 4, ensuring improved circumferential and axial fixation of the inner rings of bearing 3 and bearing 4 and gear shaft 1 without increasing the interference fit. This effectively prevents relative rotation and axial movement between the inner rings of bearing 3 and bearing 4 and gear shaft 1 during use, thus avoiding component failure due to severe wear. This improves the reducer's overhaul interval capability, prevents the accumulation of large amounts of wear debris inside the reducer, improves lubricant cleanliness, and extends the service life of gears and bearings, thereby increasing the reducer's overall service life. In this embodiment, the reducer only adds a spacer sleeve 5 to the gear shaft 1 in the original reducer gear shaft support structure with a clearance fit. This spacer sleeve presses the inner ring of the first bearing 3 against the end face, resulting in a larger contact friction force between the first bearing 3 and the first shaft shoulder 11. This not only better transmits the bearing force generated by the bevel gear mounted on the gear shaft 1 to the bearing housing 2 through the first bearing 3, but also improves the reducer's overhaul interval capability. At the same time, the overall weight increase is light, and after adding the spacer sleeve 5, the type, size, and support position of the first bearing 3 and the second bearing 4 are also different. Since the bearings remain unchanged, the meshing force (and its additional bending moment) transmitted by the first bearing 3 and the second bearing 4 remains unchanged. The contact form between the inner ring of the second bearing 4 and the gear shaft 1 and the spacer sleeve 5 remains unchanged (that is, the fit between the two ends of the inner ring of the second bearing 4 along the axial direction and the magnitude of the load it bears do not change). Therefore, the load transmission between the inner ring of the second bearing 4 and the gear shaft 1 or the spacer sleeve 5, and between the inner ring of the second bearing 4 and the limiting mechanism remains unchanged. The load on the entire gear shaft support structure of the reducer is almost negligible. Moreover, the spacer sleeve 5 and the gear shaft 1 are clearance fit, which makes them easy to install and disassemble.The reducer of this embodiment can meet the requirements of a transmission system with a large power transmission capacity without increasing the interference fit between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1. This avoids damage to the inner ring of the bearing and the journal of the gear shaft 1 when disassembling the bearing, and facilitates assembly and disassembly. In this embodiment, a spacer sleeve 5 is added between the first bearing 3 and the second bearing 4. The inner ring of the first bearing 3 fits against the first shaft shoulder 11, and the inner ring of the first bearing 3, the spacer sleeve 5, and the inner ring of the second bearing 4 are all in a compressed state. This strengthens the structure of the part of the gear shaft 1 located between the first shaft shoulder 11 and the second shaft shoulder 12 under compressive load (similar to increasing the wall thickness of the gear shaft 1 in the part where the spacer sleeve 5 is added), improves the radial stiffness of the gear shaft 1, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer. The reducer in this embodiment adds a spacer sleeve 5 to the gear shaft 1 with a clearance fit. The spacer sleeve 5 is pressed between the inner ring of the first bearing 3 and the inner ring of the second bearing 4. Compared with the existing structure, even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, it is still impossible to guarantee the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1. The reducer in this embodiment, by increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, can effectively reduce the slippage of the inner ring of the first bearing 3 relative to the journal of the gear shaft 1 and increase the contact pressure between the first bearing 3 and the gear shaft 1. It can effectively avoid the phenomenon that the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1 cannot be guaranteed even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1.

[0077] It should be noted that the reducer using the stop structure of Embodiment 1 has been proven feasible through testing, and can improve the overhaul interval capability of the reducer by 20-30%. When the reducer of a certain type of helicopter was undergoing an overhaul interval verification test, the test was terminated because the corresponding rotation between the inner ring of the bearing and the journal of gear shaft 1 occurred before the specified number of hours were completed. After adopting the stop structure of Embodiment 1, the test was successfully completed.

[0078] Example 3

[0079] This embodiment provides a transmission system including the stop structure described in Embodiment 1 or the reducer described in Embodiment 2. The transmission system of this embodiment features an axially spaced spacer 5 between the first bearing 3 and the second bearing 4, with the spacer 5 fitted over the gear shaft 1. After the limiting mechanism is installed on the gear shaft 1 and axially abuts against the inner ring of the second bearing 4, the limiting mechanism applies an axial clamping force, causing the second bearing 4 to be pressed against the spacer 5, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer 5, the axial clamping force applied to the second bearing 4 by the limiting mechanism is also applied to the first bearing 3, thereby causing the first bearing 3 to be pressed against the first shoulder 11, generating contact friction. The contact friction between the first bearing 3 and the first shoulder 11, and the contact friction between the second bearing 4 and the spacer 5, effectively prevent the first bearing 3 from... The inner ring of the first bearing 3 and the inner ring of the second bearing 4 are not subject to relative rotation and wear with the gear shaft 1. The spacer sleeve 5 is pressed between the first bearing 3 and the second bearing 4, ensuring that the circumferential and axial fixation between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1 is further improved without increasing the interference fit between the first bearing 3 and the second bearing 4 and the gear shaft 1. This effectively avoids relative rotation and axial movement between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1 during use, which could cause parts to fail due to severe wear. This not only improves the overhaul interval capability of the reducer, but also avoids the accumulation of a large amount of debris caused by wear inside the reducer, improves the cleanliness of the lubricating oil, and extends the service life of the gears and bearings, thereby improving the service life of the reducer and the transmission system. In this embodiment, the transmission system simply adds a spacer sleeve 5 to the gear shaft 1 in the original reducer gear shaft support structure with a clearance fit. This spacer sleeve presses the inner ring of the first bearing 3 against the end face, resulting in greater contact friction between the first bearing 3 and the first shaft shoulder 11. This not only better transmits the bearing force generated by the bevel gear mounted on the gear shaft 1 to the bearing housing 2 through the first bearing 3, but also improves the reducer's overhaul interval capability. Furthermore, the overall weight increase is minimal, and the addition of the spacer sleeve 5 allows for adjustments to the type, size, and support position of the first bearing 3 and the second bearing 4. Since the bearings remain unchanged, the meshing force (and its additional bending moment) transmitted by the first bearing 3 and the second bearing 4 remains unchanged. The contact form between the inner ring of the second bearing 4 and the gear shaft 1 and the spacer sleeve 5 remains unchanged (that is, the fit between the two ends of the inner ring of the second bearing 4 along the axial direction and the magnitude of the load it bears do not change). Therefore, the load transmission between the inner ring of the second bearing 4 and the gear shaft 1 or the spacer sleeve 5, and between the inner ring of the second bearing 4 and the limiting mechanism remains unchanged. The load on the entire gear shaft support structure of the reducer is almost negligible. Moreover, the spacer sleeve 5 and the gear shaft 1 are clearance fit, which makes them easy to install and disassemble.The transmission system of this embodiment can meet the requirements of a reducer in a transmission system with a large power transmission capacity without increasing the interference fit between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1. This avoids damage to the inner ring of the bearing and the journal of the gear shaft 1 when disassembling the bearing, and facilitates assembly and disassembly. In this embodiment, a spacer sleeve 5 is added between the first bearing 3 and the second bearing 4. The inner ring of the first bearing 3 fits against the first shoulder 11, and the inner ring of the first bearing 3, the spacer sleeve 5, and the inner ring of the second bearing 4 are all in a compressed state. This strengthens the structure of the portion of the gear shaft 1 located between the first shoulder 11 and the second shoulder 12 under compressive load (similar to increasing the wall thickness of the gear shaft 1 in the portion where the spacer sleeve 5 is added), improves the radial stiffness of the gear shaft 1, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer and the transmission system. The transmission system of this embodiment adds a spacer sleeve 5 to the gear shaft 1 with a clearance fit. The spacer sleeve 5 is pressed between the inner ring of the first bearing 3 and the inner ring of the second bearing 4. Compared with the existing technology, even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, it is still not possible to guarantee the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1. The transmission system of this embodiment, by increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, can effectively reduce the slippage of the inner ring of the first bearing 3 relative to the journal of the gear shaft 1 and increase the contact pressure between the first bearing 3 and the gear shaft 1. It can effectively avoid the phenomenon that the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1 cannot be guaranteed even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1.

[0080] Example 4

[0081] This embodiment provides a helicopter, including the stop structure described in Embodiment 1, the reducer described in Embodiment 2, or the transmission system described in Embodiment 3. In this embodiment, the helicopter has an axially spaced spacer 5 between the first bearing 3 and the second bearing 4, with the spacer 5 fitted over the gear shaft 1. After the limiting mechanism is installed on the gear shaft 1 and axially abuts against the inner ring of the second bearing 4, the limiting mechanism applies an axial clamping force, causing the second bearing 4 to be pressed against the spacer 5, generating contact friction. Simultaneously, through the transitional transmission effect of the intermediate spacer 5, the axial clamping force applied to the second bearing 4 by the limiting mechanism is also applied to the first bearing 3, thereby pressing the first bearing 3 against the first shoulder 11, generating contact friction. The contact friction between the first bearing 3 and the first shoulder 11, and the contact friction between the second bearing 4 and the spacer 5, effectively prevent the inner ring of the first bearing 3 from slipping. The inner rings of the first bearing 3 and the second bearing 4 rotate relative to each other and wear on the gear shaft 1. The spacer sleeve 5 is tightly fitted between the first bearing 3 and the second bearing 4, ensuring improved circumferential and axial fixation of the inner rings of the first bearing 3 and the second bearing 4 to the gear shaft 1 without increasing the interference fit. This effectively prevents relative rotation and axial movement between the inner rings of the first bearing 3 and the second bearing 4 and the gear shaft 1 during use, thus avoiding component failure due to severe wear. This improves the reducer's overhaul interval capability, prevents the accumulation of large amounts of wear debris inside the reducer, improves lubricant cleanliness, and extends the service life of gears and bearings, thereby increasing the service life of the reducer, transmission system, and helicopter. In this embodiment, the helicopter only adds a spacer sleeve 5 to the gear shaft 1 in the original gear shaft support structure with a clearance fit. This spacer sleeve presses the inner ring of the first bearing 3 against the end face, resulting in greater contact friction between the first bearing 3 and the first shoulder 11. This not only better transmits the bearing force generated by the bevel gear mounted on the gear shaft 1 to the bearing housing 2 through the first bearing 3, but also improves the gearbox overhaul interval capability. At the same time, the overall weight increase is light, and the addition of the spacer sleeve 5 changes the type, size, and support position of the first bearing 3 and the second bearing 4. Since the bearings remain unchanged, the meshing force (and its additional bending moment) transmitted by the first bearing 3 and the second bearing 4 remains unchanged. The contact form between the inner ring of the second bearing 4 and the gear shaft 1 and the spacer sleeve 5 remains unchanged (that is, the fit between the two ends of the inner ring of the second bearing 4 along the axial direction and the magnitude of the load it bears do not change). Therefore, the load transmission between the inner ring of the second bearing 4 and the gear shaft 1 or the spacer sleeve 5, and between the inner ring of the second bearing 4 and the limiting mechanism remains unchanged. The load on the entire gear shaft support structure of the reducer is almost negligible. Moreover, the spacer sleeve 5 and the gear shaft 1 are clearance fit, which makes them easy to install and disassemble.This embodiment of the helicopter can meet the requirements of a high-power transmission system reducer without increasing the interference fit between the inner ring of the first bearing 3 and the inner ring of the second bearing 4 and the gear shaft 1. This avoids damage to the inner ring of the bearing and the journal of the gear shaft 1 when disassembling the bearing, and facilitates assembly and disassembly. In this embodiment, a spacer sleeve 5 is added between the first bearing 3 and the second bearing 4. The inner ring of the first bearing 3 fits against the first shoulder 11, and the inner ring of the first bearing 3, the spacer sleeve 5, and the inner ring of the second bearing 4 are all in a compressed state. This strengthens the structure of the portion of the gear shaft 1 located between the first shoulder 11 and the second shoulder 12 under compressive load (similar to increasing the wall thickness of the gear shaft 1 in the portion with the added spacer sleeve 5), improves the radial stiffness of the gear shaft 1, makes the gear run more smoothly, and correspondingly improves the service life and working performance of the reducer, transmission system, and helicopter. In this embodiment, the helicopter adds a spacer sleeve 5 to the gear shaft 1 with a clearance fit. The spacer sleeve 5 is pressed between the inner ring of the first bearing 3 and the inner ring of the second bearing 4. Compared with the existing technology, even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, it is still impossible to guarantee the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1. In this embodiment, by increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1, the helicopter can effectively reduce the slippage of the inner ring of the first bearing 3 relative to the journal of the gear shaft 1 and increase the contact pressure between the first bearing 3 and the gear shaft 1. It can effectively avoid the phenomenon that the circumferential and axial fixation between the inner ring of the bearing and the journal of the gear shaft 1 cannot be guaranteed even after increasing the interference fit between the inner ring of the first bearing 3 and the journal of the gear shaft 1.

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A stop structure applied to a gear shaft support structure of a reducer, characterized in that, The stop structure includes: Gear shaft (1), the gear shaft (1) is configured as a stepped shaft, and a first shoulder (11) and a second shoulder (12) are provided on the gear shaft (1) from left to right along its axial direction; Bearing housing (2), the bearing housing (2) is sleeved on the outside of the gear shaft (1); The first bearing (3) is disposed between the gear shaft (1) and the bearing seat (2). The inner ring of the first bearing (3) is interference-fitted with the gear shaft (1), and one end of the first bearing (3) abuts against the first shaft shoulder (11) along the axial direction. The second bearing (4) is disposed between the gear shaft (1) and the bearing seat (2), and the inner ring of the second bearing (4) is interference-fitted with the gear shaft (1); the second bearing (4) is disposed on the right side of the second shaft shoulder (12) along the axial direction, and the end of the second bearing (4) that is axially away from the first bearing (3) is axially limited by a limiting mechanism. Spacer sleeve (5) is axially disposed between the first shoulder (11) and the second shoulder (12), and the spacer sleeve (5) is fitted with clearance fit outside the gear shaft (1); the two ends of the spacer sleeve (5) are respectively attached to the opposite ends of the first bearing (3) and the second bearing (4) to press the inner ring of the first bearing (3) tightly against the first shoulder (11).

2. The stop structure according to claim 1, characterized in that, The spacer sleeve (5) is folded radially toward the axis at one end facing the second bearing (4) to form an abutment portion (51); the abutment portion (51) is disposed between the inner ring of the second bearing (4) and the second shoulder (12).

3. A stop structure according to claim 1 or 2, characterized in that, The gear shaft (1) is provided with a first connecting part (13), a second connecting part (14), and a third connecting part (15) from left to right along its axial direction. The shaft diameters of the first connecting part (13), the second connecting part (14), and the third connecting part (15) decrease sequentially. The connection point between the first connecting part (13) and the second connecting part (14) is set as the first shaft shoulder (11), and the connection point between the second connecting part (14) and the third connecting part (15) is set as the second shaft shoulder (12). The spacer sleeve (5) is clearance-fitted with the second connecting part (14).

4. A stop structure according to claim 3, characterized in that, A fourth connecting part (16) is provided between the second connecting part (14) and the third connecting part (15). The shaft diameter of the fourth connecting part (16) is larger than that of the third connecting part (15) and smaller than that of the second connecting part (14). A third shoulder (17) is provided between the second connecting part (14) and the fourth connecting part (16). The axial distance between the first shoulder (11) and the third shoulder (17) is not greater than the axial length of the inner ring of the first bearing (3). The spacer sleeve (5) is clearance-fitted with the fourth connecting part (16). The thickness of the spacer sleeve (5) is greater than the difference in shaft diameter between the second connecting part (14) and the fourth connecting part (16).

5. A stop structure according to claim 4, characterized in that, The spacer sleeve (5) is folded radially away from the axis at one end facing the first bearing (3) to form a boss (52), and the boss (52) abuts against and fits against the inner ring of the first bearing (3).

6. A stop structure according to claim 3, characterized in that, The limiting mechanism includes a flange (7) axially locked onto the gear shaft (1) by a locking nut (6). The flange (7) abuts against the inner ring of the second bearing (4) at one end axially toward the second bearing (4) to apply an axial tightening force to the second bearing (4).

7. A stop structure according to claim 6, characterized in that, The third connecting part (15) is provided with a fifth connecting part (18) at one end opposite to the second connecting part (14). The shaft diameter of the fifth connecting part (18) is smaller than that of the third connecting part (15). The flange and the fifth connecting part (18) are connected by a spline to transmit torque.

8. A speed reducer, characterized in that, Includes the stop structure as described in any one of claims 1 to 7.

9. A transmission system, characterized in that, Includes the stop structure as described in any one of claims 1 to 7.

10. A helicopter, characterized in that, Includes the stop structure as described in any one of claims 1 to 7.

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