Hydraulic transmission and PTO shaft arrangement thereof

Abstract

The present application relates to the field of vehicle transmission, especially to a hydraulic gearbox and a PTO shaft setting structure thereof. The PTO shaft setting structure comprises a gearbox input shaft, the outer end of which extends into and is connected with a torque converter; the gearbox input shaft is a hollow shaft, and a PTO shaft is arranged in the gearbox input shaft in a concentric manner; the outer end of the PTO shaft is connected with the torque converter, and the inner end of the PTO shaft is connected with an oil pump. The PTO shaft setting structure can directly drive the oil pump through the PTO shaft from the torque converter, thereby optimizing the transmission mode of the PTO shaft; and in terms of installation mode, since the gearbox input shaft does not need to be connected with the gearbox input shaft through a gear, the installation structure is simplified, the gearbox can be made more compact, and the transmission structure space optimization on the whole machine can be facilitated.

Description

Technical Field

[0001] This invention relates to the field of vehicle transmission, and more particularly to a hydraulic transmission and its PTO shaft mounting structure. Background Technology

[0002] Due to its smooth and comfortable characteristics, hydraulic drive is increasingly widely used in various types of machinery. Since the pressure in most mechanical hydraulic systems comes from a hydraulic pump, the pump is driven in two ways: direct engine drive and belt-driven transmission. In small-tonnage forklifts, direct diesel engine drive is more common. Therefore, a PTO (Power Transfer Towing) output interface needs to be designed on the diesel engine of the forklift to drive the hydraulic pump and achieve PTO power transmission. Different PTO transmission routes and structures not only affect the compactness of the entire gearbox structure but also the overall transmission efficiency; and there is room for improvement in the existing PTO transmission routes.

[0003] For example, a hydraulic transmission gearbox is described in the publication text of Chinese invention patent CN104315109A. This hydraulic transmission gearbox includes a gearbox assembly, a reducer drive axle assembly, and a proportional hydraulic control system. The gearbox assembly and the reducer drive axle assembly are connected for power transmission via a universal joint, and the gearbox assembly and the reducer drive axle assembly are connected by a housing assembly with elastic support components. The gearbox assembly includes a gearbox housing and a torque converter housing fixed together. The torque converter assembly is housed within the torque converter housing. The gearbox housing also houses an output gear, an output flange, an intermediate shaft assembly, an input shaft assembly, an oil inlet bushing assembly, a drive gear, a PTO gear, and an internal pump gear. The input shaft assembly includes a forward gear clutch, and the intermediate shaft assembly includes a reverse gear clutch. See the appendix of this patent. Figure 2 As shown, the PTO shaft and its gear are connected to the input shaft assembly, and then the power is transmitted to the oil pump assembly through the internal pump gear.

[0004] For example, Chinese utility model patent CN210591394U discloses a tractor power take-off (PTO) device with a wet clutch. It includes a power input shaft connected to the engine, a power output shaft and a power connecting shaft sequentially sleeved on the power input shaft, a transmission output system connected to the power output shaft, a sliding sleeve slidably sleeved between the power output shaft and the power connecting shaft, a mounting seat for mounting the inner plate on the wet clutch connected to the power input shaft, and a housing for mounting the outer plate on the wet clutch connected to the housing. The housing is connected to the PTO power take-off system, and the device also includes a control system for the operation of the sliding sleeve and the wet clutch. In this design, the PTO power take-off system also uses a separate drive gear connected to the power connecting shaft. Summary of the Invention

[0005] To address the aforementioned issues, the primary objective of this invention is to provide a PTO shaft mounting structure that allows the torque converter to directly drive the oil pump via the PTO shaft, thus optimizing the PTO shaft's transmission method. Furthermore, in terms of installation, since it eliminates the need for gear connection with the gearbox input shaft, the installation structure is simplified, allowing for a more compact gearbox design and facilitating space optimization of the transmission structure within the overall machine.

[0006] A second objective of the present invention is to provide a hydraulic transmission having the aforementioned PTO shaft arrangement structure.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A PTO shaft configuration structure includes a gearbox input shaft, the outer end of which extends into a torque converter and is connected to a worm gear; characterized in that: the gearbox input shaft is a hollow shaft, a PTO shaft is inserted inside the gearbox input shaft, and the PTO shaft is concentrically arranged with the gearbox input shaft; the outer end of the PTO shaft is connected to the torque converter, and the inner end of the PTO shaft is connected to an oil pump coupling.

[0009] This invention employs the aforementioned technical solution, which relates to a PTO shaft configuration structure. In this structure, the gearbox input shaft is a hollow shaft, and the PTO shaft passes through the inside of the gearbox input shaft. With this configuration, the PTO shaft can extend out of the gearbox through a hole inside the gearbox input shaft and directly connect to the torque converter, while its inner end can also drive the oil pump. Compared to the prior art, where the PTO shaft and input shaft assembly are driven by gears, this solution allows the torque converter to directly drive the oil pump through the PTO shaft, optimizing the PTO shaft's transmission method. Furthermore, in terms of installation, since it does not require a gear connection to the gearbox input shaft, the installation structure is simplified, allowing for a more compact gearbox and facilitating space optimization of the transmission structure within the overall machine. Moreover, since the PTO shaft in this solution passes through the inside of the gearbox input shaft, and the PTO shaft configuration does not occupy any other space inside the gearbox, it effectively saves the space occupied by the traditional PTO shaft device in the gearbox.

[0010] Preferably, at least two sets of bearings are provided between the inner and outer end sidewalls of the PTO shaft and the inner wall of the shaft hole of the gearbox input shaft to realize the circumferential relative rotation between the PTO shaft and the gearbox input shaft.

[0011] Preferably, a sealing component is provided between the outer end sidewall of the PTO shaft and the inner wall of the shaft hole of the gearbox input shaft; or the bearing between the outer end sidewall of the PTO shaft and the inner wall of the shaft hole of the gearbox input shaft is a sealed bearing assembly to achieve sealing between the PTO shaft and the gearbox input shaft. In the above technical solution, the PTO shaft passes through the inside of the gearbox input shaft and can achieve circumferential relative rotation between the two, which can be achieved by using two sets of bearings at the inner and outer ends of the PTO shaft. On this basis, in order to prevent oil from the torque converter from flowing into the space between the PTO shaft and the gearbox input shaft, it is necessary to seal the outer end sidewall of the PTO shaft and the inner wall of the shaft hole of the gearbox input shaft. There are two sealing methods: one is to directly set a sealing component (such as a sealing ring) for sealing; the other is to select a sealed bearing assembly at this location, such as a bimetallic sliding bearing, which can also achieve the sealing purpose.

[0012] Preferably, the sidewall of the gearbox input shaft is provided with a first lubricating oil passage. The outer end of the first lubricating oil passage communicates with the shaft end of the central rotating shaft, and the inner end of the first lubricating oil passage is provided with a first radial oil hole communicating with the gap between the gearbox input shaft and the PTO shaft. The first radial oil hole is located on the inner wall surface of the gearbox input shaft between the two sets of bearings. Based on the above solution, this solution also needs to solve the problem of bearing lubrication between the inner and outer end sidewalls of the PTO shaft and the inner wall of the shaft hole of the gearbox input shaft. Therefore, this solution further provides a first lubricating oil passage inside the sidewall of the gearbox input shaft. The outer end of the first lubricating oil passage is opened on the shaft end of the central rotating shaft and can be used to connect the oil circuit; the inner end of the first lubricating oil passage is opened on the inner wall surface of the gearbox input shaft, from which the lubricating oil can enter the gap between the PTO shaft and the gearbox input shaft and flow to both axial ends to lubricate the bearings on both sides.

[0013] Preferably, the inner end of the first lubrication channel is further provided with a plurality of second radial oil holes, which are formed on the outer wall surface of the gearbox input shaft. Based on the above arrangement of the first lubrication channel, this scheme further considers that transmission components need to be installed on the outer side of the gearbox input shaft, and that components such as bearings also need to be lubricated. Therefore, a plurality of second radial oil holes are further provided at the inner end of the first lubrication channel for delivering lubricating oil to the outside of the gearbox input shaft.

[0014] Preferably, the outer end of the gearbox input shaft is connected to the torque converter via a turbine, and the outer end of the PTO shaft is connected to the hub of the torque converter cover.

[0015] A hydraulic transmission, characterized in that it includes the PTO shaft setting structure as described above. Attached Figure Description

[0016] Figure 1 A schematic diagram of the hydraulic transmission structure involved in this invention.

[0017] Figure 2 for Figure 1 Enlarged view of part A.

[0018] Figure 3 A schematic diagram of the clutch device involved in this invention.

[0019] Figure 4 This is a schematic diagram of the parking brake device in the hydraulic transmission. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0021] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, unless explicitly defined otherwise.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., 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.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] like Figures 1-4 The hydraulic transmission shown includes a transmission assembly and a torque converter assembly. The transmission assembly includes a transmission housing 1, and a transmission input shaft 2, a forward clutch, a reverse clutch, an output shaft assembly, and a parking brake, all disposed within the transmission housing 1. The forward clutch and reverse clutch in this embodiment share structural similarities. The specific clutches used in the forward clutch and reverse clutch are as follows:

[0026] like Figure 3 The clutch device shown includes a central shaft 10, a gear shift clutch gear 20 mounted on the central shaft 10 via bearings, and a fixed gear 30 that transmits external power to the central shaft 10 or outputs power from the central shaft 10. Depending on its location, the central shaft 10 can be a transmission input shaft 2, a forward drive shaft, or a reverse drive shaft 51. Specifically, when the clutch device is a reverse clutch device, the central shaft 10 is a reverse drive shaft 51; when the clutch device is a forward drive clutch device, the central shaft 10 is a forward drive shaft. Alternatively, referring to existing transmissions, the forward drive clutch device can be mounted on the transmission input shaft 2, in which case the central shaft 10 becomes the transmission input shaft 2. Similarly, the gear shift clutch gear 20 and the fixed gear 30 are referred to as forward drive clutch gear 41 and first gear 42 in the forward drive clutch device; and as reverse clutch gear 52 and second gear 53 in the reverse clutch device.

[0027] The aforementioned gear clutch gear 20 is connected to the central rotating shaft 10 or the fixed gear 30 via inner and outer friction plates. The fixed gear 30 is integrally connected to the central rotating shaft 10, and an axially extending portion 31 is provided on the radially outer end of the fixed gear 30. A hydraulic drive assembly is provided within the area enclosed by the axially extending portion 31 of the fixed gear 30, its main body, and the outer wall of the central rotating shaft 10. The output end of the hydraulic drive assembly can move axially along the central rotating shaft 10 and act on the inner and outer friction plates. A hydraulic cavity is formed between the hydraulic drive assembly and the main body of the fixed gear 30. The drive end of the hydraulic drive assembly is sealed to the axially extending portion 31 of the fixed gear 30 and the outer wall of the central rotating shaft 10. When the clutch device is in operation, the central rotating shaft 10 and the fixed gear 30 on it rotate, selectively driving the gear clutch gear 20 to rotate through the inner and outer friction plates, thereby controlling the closing or opening of the clutch device. As described in the background section, in existing clutch devices, the area for mounting a piston is formed between the clutch hub, the intermediate shaft body, and the radial extension, and a hydraulic cavity is formed between the piston and the radial extension of the intermediate shaft. However, in this solution, the area for mounting the hydraulic drive assembly is formed by the central shaft 10 and its integrally connected fixed gear 30. The axial extension 31 of the fixed gear 30 and the outer wall of the central shaft 10 can be sealed to the drive end of the hydraulic drive assembly, forming a hydraulic cavity between the hydraulic drive assembly and the body of the fixed gear 30. Because the central shaft 10 and the fixed gear 30 (body and axial extension 31) are integrally formed, there are no weld seams or gaps, ensuring the required strength and sealing of the hydraulic cavity and eliminating safety hazards.

[0028] The aforementioned clutch device can specifically adopt the following two clutch connection structures:

[0029] The first structure is as follows: Figure 3 As shown, a clutch hub 32 is fixedly connected to the gear clutch gear 20. The gear clutch gear 20 and clutch hub 32 are connected and fixed by rivets. The clutch hub 32 is connected to the central rotating shaft 10 via inner and outer friction plate pairs. The inner and outer friction plate pairs include multiple outer friction plates 33 and inner friction plates 34 arranged at intervals. The outer friction plates 33 are circumferentially positioned with respect to the clutch hub 32 and can move relative to it axially. The inner friction plates 34 are circumferentially positioned with respect to the central rotating shaft 10 and can move relative to it axially. In this embodiment, the clutch hub 32 is connected and fixed to the gear clutch gear 20. In existing solutions, the clutch hub 32 is welded and fixed to the central rotating shaft 10. Therefore, compared to this, the installation method of the clutch hub 32 in this solution is simplified. The clutch hub 32 does not need to be integrally welded and carburized, thus the width of the groove on the clutch hub 32 can be precisely controlled to meet the width requirements of the outer friction plates 33, achieving axial movement while avoiding vibration during use caused by circumferential looseness.

[0030] The second structural diagram is omitted; please refer to the structure disclosed in the patent document with publication number "CN104315109A". Specifically, a clutch hub 32 is fixedly connected to the fixed gear 30, and the clutch hub 32 is connected to the gear clutch gear 20 through a pair of inner and outer friction plates 33. The pair of inner and outer friction plates 33 includes multiple outer friction plates 33 and inner friction plates 34 arranged at intervals. The outer friction plates 33 are circumferentially positioned with the clutch hub 32 and can move relative to it axially, while the inner friction plates 34 are circumferentially positioned with the gear clutch gear 20 and can move relative to it axially. Although the clutch hub 32 is still connected to the fixed gear 30 as in the prior art in this embodiment, since the area for mounting the hydraulic drive component is already formed by the central rotating shaft 10 and the fixed gear 30 integrally connected thereon in the above solution, the clutch hub 32 does not need to be connected to the fixed gear 30 by welding. Instead, it can be connected by a detachable method, such as bolt / rivet connection. Therefore, compared with the existing technology of welding and fixing the clutch hub 32 to the central rotating shaft 10, this solution also simplifies the installation method of the clutch hub 32.

[0031] In a further embodiment, the hydraulic drive assembly includes a piston 35 and a compression spring 36 for driving the piston 35 to reset. A hydraulic cavity 37 is formed between the piston 35 and the body of the fixed gear 30. The two side walls of the piston 35 are sealed to the axial extension 31 of the fixed gear 30 and the outer wall of the central shaft 10. In a specific embodiment, a spring seat 38 is fixed on the outer wall of the central shaft 10. Spring mounting grooves 39 are provided on the opposite side walls of the piston 35 and the spring seat 38. The two ends of the compression spring 36 are respectively installed in the spring mounting grooves 39 of the spring seat 38 and the piston 35. In the above technical solution, the hydraulic drive assembly includes a piston 35 and a compression spring 36. The piston 35 is hydraulically driven to approach the inner and outer friction plate pairs, thereby pressing the outer friction plate 33 and the inner friction plate 34 together, increasing the friction between the outer friction plate 33 and the inner friction plate 34. At this time, the clutch device is in a closed state. The compression spring 36 pushes the piston 35 away from the inner and outer friction plates after the hydraulic pressure is removed, reducing the friction between the outer friction plate 33 and the inner friction plate 34. At this time, the clutch device is in the disengaged state.

[0032] The hydraulic oil supply path of the aforementioned clutch device is as follows: a hydraulic oil channel 101 is provided inside the shaft of the central rotating shaft 10. The outer end of the hydraulic oil channel 101 communicates with the shaft end of the central rotating shaft 10, and the inner end of the hydraulic oil channel 101 communicates with the hydraulic chamber 37. As described above, since the central rotating shaft 10 and the fixed gear 30 (body and axial extension 31) are integrally formed, a hydraulic chamber 37 that is sealed to the piston 35 is required. In order to achieve hydraulic oil supply to the hydraulic chamber 37, a hydraulic oil channel 101 is provided inside the shaft of the central rotating shaft 10, which allows the hydraulic oil channel 101 to be set up while ensuring strength.

[0033] The lubricating oil delivery path of the aforementioned clutch device is as follows: a second lubricating oil passage 102 is provided inside the shaft of the central rotating shaft 10. The outer end of the second lubricating oil passage 102 communicates with the shaft end of the central rotating shaft 10, and the inner end of the second lubricating oil passage 102 communicates with the bearings between the central rotating shaft 10 and the inner and outer friction plates, as well as the bearings between the gear clutch gear 20 and the central rotating shaft 10, which are respectively provided with at least two third radial oil holes 103. In this technical solution, the second lubricating oil passage 102 is provided inside the shaft of the central rotating shaft 10, which also achieves lubrication of the bearings and the inner and outer friction plates, and simplifies the setting of the lubricating oil path.

[0034] Using the above-described clutch device, the hydraulic transmission in this embodiment adopts the following structure. The following section, in conjunction with the accompanying drawings, describes the first clutch connection structure using the above-described clutch device. Of course, since the above-described clutch device also provides a detailed description of the second clutch connection structure, those skilled in the art can understand that it can be applied to the hydraulic transmission. In addition, since the above-described clutch device is used, the effects described in the above scheme can also be applied to the forward clutch device and / or the reverse clutch device.

[0035] The outer end of the transmission input shaft 2 extends into the torque converter 9 and connects to the worm gear. The elastic plate 91 of the torque converter 9 is connected to the engine flywheel. In this embodiment, the lateral clutch device is installed on the transmission input shaft 2, and a separate lateral shaft is not provided. Specifically, the lateral clutch device includes a lateral clutch gear 41 sleeved on the transmission input shaft 2 via bearings, a first gear 42 connected to the transmission input shaft 2, and a clutch hub 32 fixedly connected to the lateral clutch gear 41. The clutch hub 32 is connected to the transmission input shaft 2 via inner and outer friction plates. The inner and outer friction plates include multiple outer friction plates 33 and inner friction plates 34 arranged at intervals. In this lateral clutch device, the inner friction plates 34 are circumferentially positioned with respect to the transmission input shaft 2 and can move axially relative to it, while the outer friction plates 33 are circumferentially positioned with respect to the clutch hub 32 and can move axially relative to it. The traction clutch device also includes a hydraulic drive assembly. The output end of the hydraulic drive assembly can move axially along the input shaft 2 of the gearbox and act on the inner and outer friction plates to adjust the friction force between the outer friction plate 33 and the inner friction plate 34.

[0036] The first gear 42 is integrally connected and fixed to the gearbox input shaft 2. An axial extension portion 31 extending axially toward the clutch hub 32 is provided on the radially outer end of the first gear 42. A hydraulic drive assembly is disposed within the area enclosed by the axial extension portion 31 of the first gear 42, its main body, and the outer wall of the gearbox input shaft 2. A hydraulic cavity 37 is formed between the hydraulic drive assembly and the main body of the first gear 42. The drive end of the hydraulic drive assembly is in sealing engagement with the axial extension portion 31 of the first gear 42 and the outer wall of the gearbox input shaft 2. Specifically, the hydraulic drive assembly includes a piston 35 and a compression spring 36 for driving the piston 35 to return to its original position. The hydraulic cavity 37 is formed between the piston 35 and the main body of the first gear 42, and the two side walls of the piston 35 are in sealing engagement with the axial extension portion 31 of the first gear 42 and the outer wall of the gearbox input shaft 2. A spring seat 38 is fixed on the outer wall of the gearbox input shaft 2. Spring mounting grooves 39 are provided on the opposite side walls of the piston 35 and the spring seat 38. The two ends of the compression spring 36 are respectively installed in the spring mounting grooves 39 of the spring seat 38 and the piston 35.

[0037] The reverse clutch device includes a reverse shaft 51, a reverse clutch gear 52 mounted on the reverse shaft 51 via bearings, and a second gear 53 fixedly connected to the reverse shaft 51. A clutch hub 32 is fixedly connected to the reverse clutch gear 52, and the clutch hub 32 is connected to the reverse shaft 51 via inner and outer friction plates. Similarly, the inner and outer friction plates include multiple spaced outer friction plates 33 and inner friction plates 34. The outer friction plates 33 are circumferentially positioned with respect to the clutch hub 32 and can move axially relative to it, while the inner friction plates 34 are circumferentially positioned with respect to the reverse shaft 51 and can move axially relative to it. The reverse clutch device also includes a hydraulic drive assembly. The output end of the hydraulic drive assembly can move axially along the reverse shaft 51 and acts on the inner and outer friction plates to adjust the friction between the outer friction plates 33 and the inner friction plates 34.

[0038] The second gear 53 is integrally connected and fixed to the reversing axle 51. The radially outer end of the second gear 53 has an axial extension portion 31 extending axially toward the clutch hub 32. A hydraulic drive assembly is disposed within the area enclosed by the axial extension portion 31 of the second gear 53, its main body, and the outer wall of the reversing axle 51. A hydraulic cavity 37 is formed between the hydraulic drive assembly and the main body of the second gear 53. The drive end of the hydraulic drive assembly is in sealing engagement with the axial extension portion 31 of the second gear 53 and the outer wall of the reversing axle 51. Specifically, the hydraulic drive assembly includes a piston 35 and a compression spring 36 for driving the piston 35 to return to its original position. The hydraulic cavity 37 is formed between the piston 35 and the main body of the second gear 53, and the two side walls of the piston 35 are in sealing engagement with the axial extension portion 31 of the second gear 53 and the outer wall of the reversing axle 51. A spring seat 38 is fixed on the outer wall of the reversing axle 51. Spring mounting grooves 39 are provided on the opposite side walls of the piston 35 and the spring seat 38. The two ends of the compression spring 36 are respectively installed in the spring mounting grooves 39 of the spring seat 38 and the piston 35.

[0039] The output shaft device includes an output shaft 61 and an output gear 62 connected to the output shaft 61. In the above scheme, the second gear 53 meshes with the first gear 42, and the forward clutch gear 41 and the reverse clutch gear 52 mesh with the output gear 62 respectively.

[0040] 1. The power output process of the hydraulic transmission: The elastic plate 91 on the torque converter 9 is connected to the engine flywheel. The torque converter 9 transmits power to the transmission input shaft 2 through the turbine. After the driving clutch device is engaged, the power is transmitted to the driving clutch gear 41. The driving clutch gear meshes with the output gear 62 and transmits the power to the output shaft 61 for output.

[0041] 2. The reverse power output process of the hydraulic transmission: The elastic plate 91 on the torque converter 9 is connected to the engine flywheel. The torque converter 9 transmits power to the transmission input shaft 2 through the turbine. The first gear 42 and the second gear 53 mesh to transmit power to the reverse shaft 51. The reverse clutch gear meshes with the output gear 62 to transmit power to the output shaft 61 for output.

[0042] The aforementioned hydraulic transmission's forward and reverse clutch mechanisms differ from existing clutch mechanisms.

[0043] On the one hand, the clutch hub 32 in the forward clutch device and the reverse clutch device is connected and fixed to the forward clutch gear 41 / reverse clutch gear 52, while in existing solutions, the clutch hub 32 is welded and fixed to the central rotating shaft 10. Therefore, compared with this solution, the installation method of the clutch hub 32 is simplified. The clutch hub 32 does not need to be integrally welded and carburized. In this way, the width of the groove on the clutch hub 32 can be precisely controlled to meet the width of the matching with the outer friction plate 33, so as to realize axial movement and avoid vibration during use caused by circumferential loosening.

[0044] On the other hand, in existing clutch devices described in the background art, the clutch hub 32, the intermediate shaft body, and the radial extension form an area for mounting the piston 35, and the piston 35 needs to form a hydraulic chamber 37 between the clutch hub 32 and the radial extension of the intermediate shaft. In the forward clutch device of this solution, the area for mounting the hydraulic drive assembly is formed by the gearbox input shaft 2 and the first gear 42 integrally connected thereto. In the reverse clutch device, the area for mounting the hydraulic drive assembly is formed by the reverse shaft 51 and the second gear 53 integrally connected thereto. Because an integral forming process is used, there are no issues with welds and gaps, ensuring the required strength and sealing of the hydraulic chamber 37 and eliminating safety hazards.

[0045] Furthermore, the hydraulic transmission of this embodiment also includes a parking brake device, which includes a brake shaft 71 positioned inside the transmission housing 1 by bearings, and a brake cover 72 connected to the transmission housing 1. A gear on the brake shaft 71 meshes with an output gear 62 on the transmission output shaft 61, and the outer end of the brake shaft 71 is positioned in a bearing cavity in the middle of the inner end face of the brake cover 72 by bearings. The transmission housing 1 and the brake shaft 71 are connected by inner and outer friction pads. A hydraulic drive assembly is connected to the inner end of the brake cover 72, and the output end of the hydraulic drive assembly can move axially along the brake shaft 71 and act on the inner and outer friction pads. This parking brake device includes a brake shaft 71 and a brake cover 72, wherein the brake shaft 71 is positioned inside the transmission housing 1 by bearings and meshes with the transmission output shaft 61. The brake cover 72 is detachably connected to the transmission housing 1 to facilitate the installation and maintenance of the brake clutch components inside the transmission housing 1. Based on this, in this solution, the gearbox housing 1 is directly connected to the brake shaft 71 via inner and outer friction pads, and the inner and outer friction pads are controlled by a hydraulic drive assembly. When the hydraulic drive assembly presses the inner and outer friction pads together, the gearbox housing 1 provides braking torque to the brake shaft 71, further braking the output shaft 61 of the gearbox, thus achieving the purpose of parking brake. Compared with existing parking brake devices, the advantages of this solution are twofold: firstly, the gearbox housing 1 is directly connected to the brake shaft 71 via inner and outer friction pads, replacing the connection structure of multiple housings, thus eliminating concerns about the strength of the housings and end covers themselves and their connections. Secondly, the brake clutch of this parking brake device is entirely within the gearbox housing 1, allowing it to share the lubrication system within the gearbox housing 1, and eliminating concerns about the sealing of the connection points of multiple housings and end covers. This solution only needs to ensure the sealing of the connection between the gearbox housing 1 and the brake cover 72.

[0046] The hydraulic drive assembly and inner / outer friction pad pairs of this parking brake device are the same as those in the aforementioned forward and reverse clutch devices, but their installation positions differ, as detailed below:

[0047] The hydraulic drive assembly includes a piston 35 and a compression spring 36 that drives the piston 35 to return to its original position. A hydraulic cavity 37 is formed between the piston 35 and the gearbox housing 1 or the brake cover 72. One end of the compression spring 36 abuts against the piston 35, and the other end abuts against the brake cover 72 or the gearbox housing 1. In the above technical solution, the hydraulic drive assembly includes a piston 35 and a compression spring 36. The piston 35 is hydraulically driven to approach the inner and outer friction plate pair, thereby pressing the outer friction plate 33 and the inner friction plate 34 together, increasing the friction between the outer friction plate 33 and the inner friction plate 34. At this time, the clutch is in a closed state. The compression spring 36, after the hydraulic pressure is removed, pushes the piston 35 away from the inner and outer friction plate pair, reducing the friction between the outer friction plate 33 and the inner friction plate 34. At this time, the clutch is in an open state. The gearbox housing 1 has a radial extension arranged radially along the brake shaft 71. A hydraulic cavity 37 is formed between the piston 35 and the radial extension of the gearbox housing 1. At least two side walls of the piston 35 are respectively sealed against the inner wall of the gearbox housing 1 and the inner wall of the radial extension. One end of the compression spring 36 abuts against the piston 35, and the other end abuts against the brake cover 72. In this technical solution, the hydraulic cavity 37 is formed between the piston 35 and the radial extension of the gearbox housing 1, and the strength of the gearbox housing 1 can fully meet the pressure resistance requirements of the hydraulic cavity 37. Furthermore, the radial extension and the gearbox housing 1 are integrally formed (gearbox housing 1 is often integrally formed), and there will be no problem of oil leakage due to gaps caused by other connecting structures. The inner end face of the brake cover 72 and the end face of the piston 35 near the brake cover 72 are provided with spring mounting grooves 39, and the two ends of the compression spring 36 are respectively embedded in the spring mounting grooves 39 of the brake cover 72 and the piston 35. In this design, the brake cover 72 serves directly as the spring seat 38, which facilitates the installation of the compression spring 36 and eliminates the need for the spring seat 38.

[0048] The inner and outer friction pad pair includes multiple outer friction pads 33 and inner friction pads 34 arranged at intervals. The outer friction pads 33 are circumferentially positioned with respect to the gearbox housing 1 and can move relative to each other axially. The inner friction pads 34 are circumferentially positioned with respect to the brake shaft 71 and can move relative to each other axially. A baffle 73 is fixedly connected to the inner end of the gearbox housing 1. The hydraulic drive assembly and the inner and outer friction pad pair are installed in the area enclosed by the baffle 73, the brake shaft 71, the gearbox housing 1, and the brake cover 72. A guide pin 74 is fixed between the baffle 73 above the inner and outer friction pad pair and the gearbox housing 1. The guide pin 74 is axially parallel to the brake shaft 71, and the outer friction pads 33 are circumferentially positioned with respect to the guide pin 74 and can move relative to each other axially.

[0049] In a further embodiment, the input shaft 2 of the hydraulic transmission is a hollow shaft, and a PTO shaft 8 passes through the inside of the input shaft 2, concentrically arranged with the input shaft 2. The outer end of the PTO shaft 8 is connected to the worm gear inside the torque converter 9, and the inner end of the PTO shaft 8 is connected to the oil pump coupling. Specifically, the outer end of the input shaft 2 is connected to the worm gear inside the torque converter 9 via a worm, and the outer end of the PTO shaft 8 is connected to the worm gear of the torque converter 9. This technical solution relates to a PTO shaft arrangement structure. In this structure, the input shaft 2 is a hollow shaft, and the PTO shaft 8 passes through the inside of the input shaft 2. With this arrangement, the PTO shaft 8 can extend out of the transmission through a shaft hole inside the input shaft 2 and directly connect to the torque converter 9, while its inner end can also directly drive the oil pump. Compared to the prior art, where the PTO shaft 8 and the input shaft assembly are connected via gear transmission. This design allows the torque converter 9 to directly drive the oil pump via the PTO shaft 8, optimizing the transmission method of the PTO shaft 8. Furthermore, in terms of installation, since it does not require a gear connection with the gearbox input shaft 2, the installation structure is simplified, allowing for a more compact gearbox and facilitating space optimization of the transmission structure within the overall machine. Moreover, the PTO shaft 8 in this design is housed within the gearbox input shaft 2, and its placement does not occupy any other space within the gearbox, effectively saving the space typically occupied by the PTO shaft 8 in traditional gearboxes.

[0050] In this design, at least two sets of bearings are provided between the inner and outer end sidewalls of the PTO shaft 8 and the inner wall of the shaft hole of the gearbox input shaft 2, enabling circumferential relative rotation between the PTO shaft 8 and the gearbox input shaft 2. Additionally, a sealing component is provided between the outer end sidewall of the PTO shaft 8 and the inner wall of the shaft hole of the gearbox input shaft 2. Alternatively, the bearing between the outer end sidewall of the PTO shaft 8 and the inner wall of the shaft hole of the gearbox input shaft 2 can be a sealed bearing assembly to achieve a seal between the PTO shaft 8 and the gearbox input shaft 2. In the above technical solution, the PTO shaft 8 passes through the inside of the gearbox input shaft 2 and enables circumferential relative rotation between the two, which can be achieved by using two sets of bearings at the inner and outer ends of the PTO shaft 8. Furthermore, to prevent oil from the torque converter 9 from flowing into the space between the PTO shaft 8 and the gearbox input shaft 2, it is necessary to seal the outer end sidewall of the PTO shaft 8 and the inner wall of the shaft hole of the gearbox input shaft 2. There are two sealing methods: one is to directly install a sealing component (such as a sealing ring) for sealing. Another option is to select a sealed bearing assembly for the bearing at this location, such as a bimetallic sliding bearing 81 (shown in the figure), which can also achieve the purpose of sealing.

[0051] Based on the above structure, the lubrication structure of the hydraulic transmission in this solution is as follows:

[0052] 1. The sidewall of the gearbox input shaft 2 is provided with a first lubricating oil passage 104. The outer end of the first lubricating oil passage 104 communicates with the shaft end of the gearbox input shaft 2. The inner end of the first lubricating oil passage 104 is provided with a first radial oil hole 105 opened on the inner wall surface of the gearbox input shaft 2, and at least two second radial oil holes 106 opened on the outer wall surface of the gearbox input shaft 2. The first radial oil hole 105 is in communication with the gearbox input shaft 2 and the PTO shaft 8 through a gap. The two second radial oil holes 106 are respectively oriented towards the inner and outer friction plates and the bearing between the clutch gear 41 and the gearbox input shaft 2. The inner end of the second radial oil hole 106 can be directly connected to the first lubricating oil passage 104 or in communication with the gearbox input shaft 2 and the PTO shaft 8 through a gap. Based on the above solution, this solution also needs to solve the lubrication problem of the bearing between the inner and outer end sidewalls of the PTO shaft 8 and the inner wall of the shaft hole of the gearbox input shaft 2, as well as the lubrication problem in the clutch device. Therefore, this solution further includes a first lubrication channel 104 inside the side wall of the gearbox input shaft 2. The outer end of the first lubrication channel 104 is located on the shaft end of the central rotating shaft 10 and can be used to connect to the oil circuit. The inner end of the first lubrication channel 104 is located on the inner wall of the gearbox input shaft 2, allowing lubricant to enter the gap between the PTO shaft 8 and the gearbox input shaft 2 and flow axially to both ends to lubricate the bearings on both sides. Simultaneously, considering the lubrication of the clutch mechanism on the outside of the gearbox input shaft 2, several second radial oil holes 106 are also provided at the inner end of the first lubrication channel 104 to deliver lubricating oil to the outside of the gearbox input shaft 2. Through the above structure, this solution can achieve targeted lubrication of the inner and outer friction plates and bearings within the clutch mechanism. The lubrication efficiency is higher, meaning lubrication is achieved with a smaller amount of lubricating oil.

[0053] 2. The reverse axle 51 has a second lubrication channel 102 inside its shaft. The outer end of the second lubrication channel 102 communicates with the shaft end of the reverse axle 51, and the inner end of the second lubrication channel 102 communicates with at least two third radial oil holes 103, which are respectively connected to the inner and outer friction plates and the bearing between the reverse clutch gear 52 and the reverse axle 51. This technical solution is for lubricating the components in the reverse clutch device. Similar to the aforementioned forward clutch device, its effect is to achieve targeted lubrication of the inner and outer friction plates and bearings in the clutch device, resulting in higher lubrication efficiency, i.e., lubrication is achieved with less lubricating oil.

[0054] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0055] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A PTO shaft configuration structure, comprising a gearbox input shaft (2), wherein the outer end of the gearbox input shaft (2) extends into a torque converter (9) and is connected to a turbine; characterized in that: The gearbox input shaft (2) is a hollow shaft, and a PTO shaft (8) is inserted inside the gearbox input shaft (2). The PTO shaft (8) is concentrically arranged with the gearbox input shaft (2). The outer end of the PTO shaft (8) is connected to the turbine inside the torque converter (9), and the inner end of the PTO shaft (8) is connected to the oil pump coupling. At least two sets of bearings are provided between the inner and outer end sidewalls of the PTO shaft (8) and the inner wall of the shaft hole of the gearbox input shaft (2) to realize the circumferential relative rotation of the PTO shaft (8) and the gearbox input shaft (2); The side wall of the gearbox input shaft (2) is provided with a first lubricating oil passage (104). The outer end of the first lubricating oil passage (104) is connected to the shaft end of the gearbox input shaft (2). The inner end of the first lubricating oil passage (104) is provided with a first radial oil hole (105) which is connected to the gap between the gearbox input shaft (2) and the PTO shaft (8). The first radial oil hole (105) is located on the inner wall surface of the gearbox input shaft (2) between the two sets of bearings. The inner end of the first lubricating oil passage (104) is also provided with a number of second radial oil holes (106), which are opened on the outer wall surface of the gearbox input shaft (2); the two second radial oil holes (106) are respectively facing the inner and outer friction plates and the bearing between the clutch gear (41) and the gearbox input shaft (2); The gearbox input shaft (2) is equipped with a traction clutch device, which includes a traction clutch gear (41) sleeved on the gearbox input shaft (2) by a bearing, a first gear (42) fixed on the gearbox input shaft (2), and a clutch hub (32) fixedly connected to the traction clutch gear (41). The clutch hub (32) is connected to the gearbox input shaft (2) through an inner and outer friction plate pair. The inner and outer friction plate pair includes multiple outer friction plates (33) and inner friction plates (34) arranged at intervals. The radial outer end of the first gear (42) is provided with an axial extension (31) that extends axially toward the clutch hub (32). The hydraulic drive assembly is disposed in the area enclosed by the axial extension (31) of the first gear (42), the main body and the outer wall of the gearbox input shaft (2). A hydraulic cavity (37) is formed between the hydraulic drive assembly and the main body of the first gear (42). The drive end of the hydraulic drive assembly is sealed and fitted with the axial extension (31) of the first gear (42) and the outer wall of the gearbox input shaft (2).

2. The PTO axis setting structure according to claim 1, characterized in that: A sealing component is provided between the outer end sidewall of the PTO shaft (8) and the inner wall of the shaft hole of the gearbox input shaft (2); or the bearing between the outer end sidewall of the PTO shaft (8) and the inner wall of the shaft hole of the gearbox input shaft (2) is a sealed bearing assembly to achieve sealing between the PTO shaft (8) and the gearbox input shaft (2).

3. A hydraulic transmission, characterized in that: Includes the PTO axis setting structure as described in claim 1 or 2.

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