Transmission shaft mounting structure for transmission and transmission
By combining internal and external bearings and designing radial load-bearing bearings, the problem of reverse axial force changes during forward and reverse rotation of the gearbox is solved, achieving uniform force distribution on the bearings and improving the reliability and service life of the gearbox.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZOOMLION HEAVY INDUSTRY SCIENCE AND TECHNOLOGY CO LTD
- Filing Date
- 2025-08-08
- Publication Date
- 2026-08-04
AI Technical Summary
In existing gearbox designs, a single bearing configuration cannot effectively cope with the reverse changes in the direction of axial force during forward and reverse rotation of the gearbox. This results in the bearing being unable to uniformly bear the axial force from different directions, affecting the reliability and service life of the gearbox.
The system employs a combined structure with inner and outer bearings arranged in opposite directions. The inner and outer bearings bear the opposite axial forces when the drive shaft rotates in different directions, and the radial bearings distribute the axial load at high speeds, ensuring uniform bearing force and avoiding localized stress concentration.
This achieves uniform stress distribution on the bearings, improves bearing durability and service life, and enhances the operational reliability of the drive shaft under high speed and high torque conditions.
Smart Images
Figure CN224592645U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of agricultural machinery, specifically to a drive shaft mounting structure for a gearbox. Based on this, the utility model also provides a gearbox equipped with this drive shaft mounting structure. Background Technology
[0002] With the rapid development of agricultural machinery, especially in the widespread application of high-horsepower tractors, the gearbox, as its core transmission component, needs to cope with the dual challenges of high speed and high torque. Under these complex working conditions, the bearing design of the gearbox must have higher load-bearing capacity and stability to ensure its long-term reliable operation. However, existing gearbox designs often use a single bearing configuration, which is prone to performance degradation under high-load conditions.
[0003] In existing technologies, during the transition between forward and reverse rotation of a transmission, the direction of the axial force on the intermediate shaft within the transmission changes in the opposite direction. However, traditional single-bearing configurations cannot effectively cope with this reverse change in axial force, resulting in the bearing being unable to uniformly bear the axial forces from different directions, thus affecting the reliability and service life of the transmission. Utility Model Content
[0004] The purpose of this invention is to overcome the problem in the existing technology that it cannot uniformly bear axial forces from different directions.
[0005] To achieve the above objectives, the first aspect of this utility model provides a drive shaft mounting structure for a gearbox, including a housing and a drive shaft rotatably mounted within the housing via a bearing assembly. The bearing assembly includes an inner bearing and an outer bearing, which are arranged in pairs facing each other and support one end of the drive shaft on the housing, so as to withstand axial forces in opposite directions transmitted by the drive shaft when the drive shaft rotates in different directions.
[0006] Optionally, the bearing assembly may also include radial load bearings arranged axially spaced relative to the inner and outer bearings to support the drive shaft on the housing at the interval between the inner and outer bearings.
[0007] Optionally, the inner and outer bearings include tapered bearings, and the radial load bearings include radial load bearings.
[0008] Optionally, a bearing housing is fixedly connected to the outer casing, and the inner bearing and the outer bearing are mounted to the same support wall of the outer casing through the bearing housing.
[0009] Optionally, an annular protrusion is formed on the inner side of the bearing housing, and the ends of the inner bearing and the outer bearing abut against each other on both sides of the annular protrusion.
[0010] Optionally, an adjusting shim is provided between the annular protrusion and the inner bearing so that the axial position of the drive shaft within the housing can be changed by adjusting the thickness of the adjusting shim.
[0011] Optionally, a locking element is also connected to the drive shaft for applying a preload force along the axial direction of the drive shaft to the external bearing.
[0012] Optionally, the locking element includes an inner fastening nut that is threaded to the drive shaft and abuts against the side of the inner ring of the outer bearing away from the inner bearing to apply a preload to the inner ring.
[0013] Optionally, the locking component also includes an outer fastening nut for limiting the rotation of the inner fastening nut. The outer fastening nut is located on the side of the inner fastening nut facing away from the outer bearing. A locking washer is provided between the outer fastening nut and the inner fastening nut to limit the rotation of the outer fastening nut.
[0014] The second aspect of this utility model provides a drive shaft mounting structure for a gearbox, including the drive shaft mounting structure for a gearbox as described above and an input shaft disposed within a housing, the input shaft being drive-connected to the drive shaft.
[0015] Through the above technical solution, this utility model adopts a combination structure of a pair of inner and outer bearings in the bearing assembly, wherein the inner and outer bearings are arranged facing each other, so that they can withstand the axial force in opposite directions transmitted by the transmission shaft when the transmission shaft rotates in different directions. Compared with the traditional bearing configuration that is subjected to force in a single direction, this design effectively disperses the axial load, so that the bearings on both sides are subjected to force alternately and the load distribution is more uniform, thereby avoiding local stress concentration and abnormal wear of the bearing, improving the durability of the bearing and extending its service life. Attached Figure Description
[0016] Figure 1 This is a schematic diagram of the intermediate shaft structure of this utility model; Figure 2 This is a schematic diagram of the structure of the inner bearing and the outer bearing of this utility model; Figure 3 This is a schematic diagram of the locking component structure of this utility model. Detailed Implementation
[0017] The specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of this utility model.
[0018] like Figure 1 As shown, the drive shaft 2 mounting structure for a gearbox in this utility model includes a housing 1 and a drive shaft 2 rotatably mounted in the housing 1 via a bearing assembly 4.
[0019] The outer shell 1 may include a front shell 101 and a rear shell 102.
[0020] The bearing assembly 4 may include an inner bearing 401 and an outer bearing 402, which are arranged in pairs facing each other to withstand axial forces in opposite directions transmitted by the drive shaft when the drive shaft rotates in different directions, and to support one end of the drive shaft 2 on the housing 1. Figure 1 In the illustrated embodiment, the inner bearing 401 and the outer bearing 402 can support one end of the drive shaft 2 located inside the front housing 101 of the housing 1 on the housing 1 to axially position that end of the drive shaft 2, thereby restricting its axial movement.
[0021] Therefore, in this invention, the inner bearing 401 and the outer bearing 402 may include tapered roller bearings or other suitable bearing types. It is understood that by arranging the rollers of the two tapered roller bearings at opposite angles, they bear axial forces in different directions during the forward and reverse rotation of the drive shaft 2. That is, when the drive shaft 2 rotates in a certain direction, such as forward rotation, the axial force is mainly borne by the inner bearing 401; while when the drive shaft 2 rotates in the reverse direction (reverse rotation), the direction of the axial force is reversed, and the outer bearing 402 mainly bears this reverse axial force.
[0022] Therefore, compared with the traditional bearing configuration of existing technology that is subjected to force in one direction, this design effectively disperses the axial load, so that the bearings on both sides are subjected to force alternately and the load distribution is more even, thereby avoiding local stress concentration and abnormal wear of the bearing, improving the durability of the bearing and extending its service life.
[0023] Of course, this installation method can be adapted to the actual situation. For example, the inner bearing 401 and the outer bearing 402 can be installed inside the rear shell 102 of the outer shell 1 to support the corresponding end of the drive shaft 2 on the outer shell 1. At the same time, the inner bearing 401 and the outer bearing 402 can be the same size.
[0024] In this invention, the drive shaft 2, as the core component for power transmission, needs to withstand large torques and adapt to high-speed operation during operation, thus placing higher performance requirements on its support structure. Therefore, the aforementioned bearing assembly 4 also includes a radial bearing 403 arranged axially spaced relative to the inner bearing 401 and outer bearing 402, to support the drive shaft 2 on the housing 1 at a distance from the inner bearing 401 and outer bearing 402. The radial bearing 403 can be located within the rear shell 102 of the housing 1. It is understood that the radial bearing 403 possesses excellent radial load-bearing capacity and good rolling characteristics, enabling it to maintain low-friction operation at high speeds, effectively reducing heat generation and wear. Simultaneously, it can stably withstand the large radial load caused by large torque, thereby allowing the drive shaft 2 to withstand larger radial forces at high speeds.
[0025] It is worth noting that the radial bearing 403 can only withstand radial forces, while allowing the drive shaft 2 a certain degree of freedom of movement in the axial direction. Therefore, the radial bearing 403 may include a radial bearing or other suitable bearing types.
[0026] Therefore, through the structural design of the bearing assembly 4, this utility model allows the drive shaft 2 to be installed inside the housing 1 with one end fixed and the other end movable. This arrangement allows the axial displacement to be released from the movable end when the drive shaft 2 undergoes axial elongation or contraction due to thermal expansion or load changes, preventing the drive shaft 2 from "jamming" or the bearing from being damaged due to tensile or compressive stress. This effectively improves the operational reliability and overall service life of the drive shaft 2 under high speed and high torque conditions.
[0027] In some embodiments, such as Figure 1 As shown, a bearing seat 5 is fixedly connected to the outer casing 1. The inner bearing 401 and the outer bearing 402 are both mounted to the same support wall of the outer casing 1 through the bearing seat 5. In this utility model, the bearing seat 5 can be disposed on the front shell 101 of the outer casing 1.
[0028] Furthermore, such as Figure 2 As shown, an annular protrusion 501 protruding radially inward is formed on the inner side of the bearing housing 5, which effectively separates the inner bearing 401 and the outer bearing 402 structurally. Specifically, the ends of the inner bearing 401 and the outer bearing 402 abut against each other on both sides of the annular protrusion 501, maintaining a distance between them in the axial direction. This achieves the structural requirement of facing arrangement and prevents interference between the bearings due to thermal expansion or load changes during operation. At the same time, the inner and outer bearings 402 are positioned by the same bearing housing 5, reducing assembly errors, improving the operational coordination of the bearing assembly 4, and facilitating the coordinated bearing capacity when the transmission shaft 2 is subjected to bidirectional axial forces.
[0029] To facilitate adjustment of the meshing state between the gear 3 on the drive shaft 2 and the gear 3 connected to other shaft systems (such as the input shaft) in the transmission, this invention provides an adjusting shim 601 between the annular protrusion 501 and the inner bearing 401. By adjusting the thickness of the adjusting shim 601, for example by replacing it with an adjusting shim 601 of different thicknesses, the axial position of the drive shaft 2 within the housing 1 is changed, thereby causing the gear 3 fixedly connected to the drive shaft 2 to move closer to or further away from the corresponding gear 3, thus adjusting the engagement depth between the meshing gears 3 and optimizing the contact position and contact area between the teeth. Of course, in other embodiments, the adjusting shim 601 can also be replaced with a retaining ring or baffle of appropriate thickness.
[0030] In some embodiments, the drive shaft 2 is further provided with a locking member 7 for applying axial preload to the outer bearing 402, so that a moderate contact pressure is formed between the rolling elements and the raceway of the outer bearing 402, thereby eliminating bearing clearance and improving its rigidity and running accuracy.
[0031] The locking member 7 may have any suitable structure, such as Figure 1 In the illustrated embodiment, the locking element 7 may include an inner fastening nut 701, which is threaded to the drive shaft 2 and abuts against the side of the inner ring of the outer bearing 402 away from the inner bearing 401 to apply a preload to the inner ring. By tightening the fastening nut, the inner ring of the outer bearing 402 can be pushed inward in the axial direction, causing it to tend to displace axially relative to the outer ring. This results in appropriate contact pressure between the rolling elements and the raceway. This contact pressure eliminates the initial clearance of the outer bearing 402 body, allowing the rolling elements to maintain a good stress state during operation, thereby improving the rigidity and operating accuracy of the bearing and ensuring the stability and reliability of the transmission system under high speed and high load conditions.
[0032] In some embodiments, such as Figure 2 As shown, the locking member 7 also includes an outer locking nut 702 for restricting the rotation of the inner locking nut 701. The outer locking nut 702 is located on the side of the inner locking nut 701 facing away from the outer bearing 402. Therefore, in this invention, by tightening the outer locking nut 702, the static friction force on the side of the outer locking nut 702 facing away from the outer bearing 402 is increased, thereby significantly increasing the resistance that the inner locking nut 701 needs to overcome to rotate, thus preventing loosening.
[0033] A locking washer 703 is provided between the outer fastening nut 702 and the inner fastening nut 701, and the locking washer 703 is used to restrict the rotation of the outer fastening nut 702.
[0034] In this utility model, the locking washer 703 can have any suitable structure, such as Figure 3In the embodiment shown, the inner circumferential side of the locking washer 703 may be provided with a protrusion that protrudes radially inward. Correspondingly, the threaded structure at the end of the rotating shaft is provided with a groove that extends axially, so as to simultaneously restrict the rotation of the locking washer 703 relative to the transmission shaft 2, thereby achieving an effective anti-rotation effect on the locking washer 703.
[0035] Secondly, the outer periphery of the locking washer 703 is provided with multiple radially outward protruding flat plates, and the outer fastening nut 702 is correspondingly provided with multiple grooves for the flat plates to be inserted. By tapping these protruding flat plates, they are moved towards the outer fastening nut 702 and embedded in the corresponding grooves, thereby achieving a fixed connection between the outer fastening nut 702 and the locking washer 703, thus restricting the rotation of the outer fastening nut 702.
[0036] In some embodiments, the above-described drive shaft 2 mounting structure for the gearbox further includes an end cover 8, which covers the side of the drive shaft 2 where the locking member 7 is located, and the open side of the end cover 8 is connected to the bearing seat 5 to prevent external impurities from entering the mounting part of the drive shaft 2 and to prevent the inner and outer bearings 402 from being contaminated.
[0037] The second aspect of this utility model provides a gearbox, including the drive shaft 2 mounting structure for the gearbox as described above and an input shaft disposed within the housing 1, the input shaft being tractively connected to the drive shaft 2.
[0038] Generally, in a transmission structure, if an input shaft, output shaft, and intermediate shaft are all provided, then the aforementioned transmission shaft 2 can be the intermediate shaft; if only an input shaft and output shaft are provided, then the aforementioned transmission shaft 2 can be the output shaft. Specifically, the force state of the aforementioned bearing assembly 4 can be explained using the intermediate shaft as an example. During transmission, the gear 3 on the intermediate shaft generates axial and radial components due to the meshing angle. Both the radial and axial components are transmitted from the gear 3 to the intermediate shaft body through an interference fit or key connection, and then from the intermediate shaft to the bearing assembly 4 mounted on it. Specifically, as... Figure 1 As shown, the fixed end of the intermediate shaft is equipped with an inner bearing 401 and an outer bearing 402. During the forward or reverse rotation of the intermediate shaft, the radial component force generated by the gear 3 is transmitted to the intermediate shaft body through the mating structure between the gear 3 and the intermediate shaft. This force is borne by the radial bearing 403 at the floating end of the intermediate shaft, as well as the inner bearing 401 and outer bearing 402 at the fixed end. It should be noted that the radial component force acting on the inner bearing 401 and outer bearing 402 will also induce derived axial forces along their respective axial bearing directions on both bearings. These derived axial forces are borne by the inner bearing 401 and outer bearing 402 themselves.
[0039] The axial force exerted by gear 3 on the intermediate shaft is in the same direction as the axial bearing direction of the inner bearing 401, so this axial force is borne by the inner bearing 401. At this time, the outer bearing 402 does not bear the load in this direction because its axial bearing direction is opposite to that axial force. Conversely, when the intermediate shaft reverses direction, the axial force generated by gear 3 reverses direction and becomes consistent with the bearing direction of the outer bearing 402. Thus, the outer bearing 402 bears the reverse axial force, while the inner bearing 401 no longer bears the load in this direction.
[0040] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and all fall within the protection scope of the present invention.
Claims
1. A propeller shaft mounting structure for a transmission case, comprising a housing (1) and a propeller shaft (2) rotatably mounted to the housing (1) by a bearing set (4), characterized in that, The bearing assembly (4) includes an inner bearing (401) and an outer bearing (402), which are arranged in pairs facing each other and support one end of the drive shaft (2) on the housing (1). The inner bearing (401) and the outer bearing (402) are tapered bearings, and the rollers of the two tapered bearings are arranged obliquely oppositely so as to withstand the axial force transmitted by the drive shaft (2) in opposite directions when the drive shaft (2) rotates in different directions.
2. The propeller shaft mounting structure for a transmission according to claim 1, characterized by, The bearing assembly (4) further includes a radial bearing (403) arranged axially spaced relative to the inner bearing (401) and the outer bearing (402) to support the drive shaft (2) on the housing (1) at the spaced position between the inner bearing (401) and the outer bearing (402).
3. The propeller shaft mounting structure for a transmission according to claim 1, characterized by, A bearing seat (5) is fixedly connected to the outer shell (1), and the inner bearing (401) and the outer bearing (402) are installed on the same support wall of the outer shell (1) through the bearing seat (5).
4. The propeller shaft mounting structure for a transmission according to claim 3, characterized by, The bearing housing (5) has an annular protrusion (501) that protrudes radially inward on its inner side, and the ends of the inner bearing (401) and the outer bearing (402) abut against each other on both sides of the annular protrusion (501).
5. The propeller shaft mounting structure for a transmission according to claim 4, characterized by, An adjusting shim (601) is provided between the annular protrusion (501) and the inner bearing (401) so that the axial position of the drive shaft (2) in the housing (1) can be changed by adjusting the thickness of the adjusting shim (601).
6. The propeller shaft mounting structure for a transmission according to claim 1, characterized by, The drive shaft (2) is also connected to a locking member (7) for applying a preload force to the outer bearing (402) in the axial direction of the drive shaft (2).
7. The propeller shaft mounting structure for a transmission according to claim 6, characterized by The locking element (7) includes an inner fastening nut (701) which is threaded to the drive shaft (2) and abuts against the side of the inner ring of the outer bearing (402) away from the inner bearing (401) to apply a preload to the inner ring.
8. The propeller shaft mounting structure for a transmission according to claim 7, characterized by, The locking member (7) further includes an outer locking nut (702) for restricting the rotation of the inner locking nut (701), the outer locking nut (702) being located on the side of the inner locking nut (701) facing away from the outer bearing (402). A locking washer (703) is provided between the outer fastening nut (702) and the inner fastening nut (701), and the locking washer (703) is used to restrict the rotation of the outer fastening nut (702).
9. A gearbox characterized in that, Includes a drive shaft (2) mounting structure for a gearbox as described in any one of claims 1-8 and an input shaft disposed within the housing (1), the input shaft being drive-connected to the drive shaft (2).