Transmission gear and gearbox with integrated torque limiting protection function

Abstract

The utility model relates to a kind of transmission gear and gearbox of integrated limit torque protection function, belong to hybrid vehicle or pure electric vehicle power transmission system technical field, solve the problem of broken axle or electromagnetic clutch easy to damage caused by excessive impact torque of wheel end pavement.This utility model includes outer tooth component, friction plate, transmission torque disc and cover plate, the utility model uses friction plate and transmission torque disc and other structures, when impact torque is less than specific value, transmission torque disc and friction plate rotate synchronously, when impact torque is greater than specific value, transmission torque disc and friction plate slide relative, the purpose of integrating limit torque protection function in transmission gear is achieved.

Description

Technical Field

[0001] This utility model relates to the technical field of power transmission systems for hybrid or pure electric vehicles, and in particular to a transmission gear and gearbox with integrated torque limiting protection function. Background Technology

[0002] The drivetrain systems of hybrid or pure electric vehicles are prone to damage when encountering road impacts. Specifically, the impact conditions of hybrid systems can be categorized into misfire impacts in series mode, misfire impacts in parallel mode, and road impacts. For misfire impacts, the misfire impact area can be avoided by adjusting the misfire strategy. However, in parallel mode, when the vehicle impacts bumpy roads, double-U roads, or during emergency ABS braking, the system experiences impact torque from the wheel ends, which cannot be avoided through calibration strategies. Especially in hybrid transmissions that use electromagnetic clutches instead of traditional wet clutches, the lack of impact slippage protection on the electromagnetic clutch means that even with torque-limiting dampers at the engine output, the risk of road impact torque at the wheel ends cannot be fundamentally reduced. Pure electric vehicle powertrain systems also experience impact conditions from the road surface at the wheel ends. This problem exists primarily because:

[0003] 1. Compared to wet clutches, electromagnetic clutches lack the buffering effect of liquid, and the impact force is directly transmitted to the mechanical structure; 2. The rapid response characteristics of the electric motor in a hybrid system may exacerbate the impact, leading to torque fluctuations; 3. When a vehicle suddenly switches from a high-friction surface to a low-friction surface, the sudden change in tire grip will cause a sudden change in the speed of the drive wheels, generating a huge speed difference within the transmission system and forming impact torque.

[0004] Therefore, a transmission gear structure with impact protection function needs to be designed to reduce the occurrence of shaft breakage or electromagnetic clutch damage. Utility Model Content

[0005] Based on the above analysis, the present invention aims to provide a transmission gear with integrated torque limiting protection function to solve the problem of shaft breakage or easy damage to electromagnetic clutch caused by excessive impact torque on the wheel end road surface.

[0006] On one hand, this utility model provides a transmission gear with integrated torque limiting protection function, including an external gear component, a torque limiter assembly, and an internal gear component, all of which are ring-shaped. The external gear component is connected to the internal gear component through the torque limiter assembly to resist torque. The torque limiter assembly includes a friction plate, a torque transmission disc, and a cover plate. An external gear ring is provided on the outer circumferential surface of the external gear component, and a first internal gear ring is provided on the inner circumferential surface of the external gear component; the outer circumferential surface of the friction plate is provided with teeth that mesh with the first internal gear ring; the torque transmission disc is in contact with the friction plate; the cover plate is fixedly connected to the side of the external gear component to provide axial pressure on the friction plate and the torque transmission disc, thereby allowing torque to be transmitted between the external gear component and the internal gear component through the torque limiter assembly. When the torque exceeds a preset threshold, relative sliding can occur between the friction plate and the torque transmission disc.

[0007] Compared to existing technologies, the transmission gear provided by this invention integrates the torque limiting protection mechanism directly inside the transmission gear (through the sliding pair design of the friction plate and the torque transmission disc), reducing the number of independent components in the transmission chain and simplifying the system architecture. The external gear component, friction plate, torque transmission disc, and cover plate all have a ring-shaped nested structure with a compact axial layout, meeting the requirements of hybrid and pure electric vehicles for lightweight and small size.

[0008] Furthermore, a stepped hole is axially formed in the middle of the external gear component. The stepped hole includes a first section and a second section. The first internal gear ring is disposed on the hole wall of the second section, and the cover plate is installed in the first section. Through axial layered layout, the internal space utilization of the gear is optimized, the axial redundant length is reduced, and the lightweight requirements of the hybrid system are met. In addition, the stepped hole provides installation space for the cover plate.

[0009] Furthermore, the torque limiter assembly also includes a pressure plate and a diaphragm spring. The pressure plate presses against the friction plates and the torque transmission plate, while the diaphragm spring is installed between the pressure plate and the cover plate. The diaphragm spring provides elastic preload, automatically compensating for friction plate wear under impact conditions, maintaining stable clamping force, and extending service life. The elastic characteristics of the diaphragm spring absorb high-frequency vibrations during transmission, reducing noise and improving driving comfort. By adjusting the diaphragm spring stiffness, the sliding torque threshold of the friction pair can be precisely set, enhancing the reliability of torque limiting protection.

[0010] Furthermore, multiple friction plates and torque transmission discs are provided, and they are arranged alternately. The multi-layered friction pairs synchronously share the torque, reducing the force on a single contact surface by more than 60%, significantly reducing wear and heat accumulation. Even if a single friction pair fails, the remaining layers can temporarily maintain the transmission function, improving the system's fault tolerance. Further still, there is one more friction plate than torque transmission disc. The friction plates are located in the innermost and outermost layers of the laminated structure, ensuring symmetrical transmission of axial clamping force and avoiding eccentric deformation caused by unilateral pressure on the torque transmission disc. The outer friction plate directly contacts the cover plate or pressure plate, reducing the risk of displacement of the torque transmission disc during clamping and enhancing structural rigidity.

[0011] Furthermore, the torque transmission disc has a connecting structure designed with internal splines on its inner circumferential surface, and the internal gear component is designed as a spline hub. The outer circumferential surface of the spline hub is provided with external splines that mesh with the internal splines, and the inner circumferential surface of the spline hub is provided with a second internal gear ring. The spline hub and the torque transmission disc are precisely matched through splines, eliminating assembly eccentricity and reducing transmission vibration and noise. The second internal gear ring of the spline hub can connect to other gears or shafts, facilitating integration into different transmission systems and expanding application scenarios. More preferably, the spline hub and the external gear component have the same axial dimensions, and the external splines are located in the middle of the outer circumferential surface of the spline hub. Bearings are also fitted on the outer circumferential surface of the spline hub, with the bearings located on both sides of the external splines. The bearings are symmetrically distributed on both sides of the splines, balancing the radial load during transmission, preventing shaft misalignment, and extending bearing life. Preferably, bearing seals can also be provided. The seals prevent foreign objects from entering the bearing raceway, reducing abnormal wear of the friction pair, ensuring transmission efficiency, reducing grease leakage, lowering maintenance frequency, and making it suitable for harsh working environments. Another option is to design the torque transmission disc and the internal gear component as a single unit, that is, to directly transmit torque to other components through the torque transmission disc, thereby reducing the overall number of components and simplifying the assembly process.

[0012] Furthermore, multiple positioning holes are provided at corresponding positions on the friction plate and the external gear component. These positioning holes provide a mechanical alignment reference, ensuring the meshing accuracy of the friction plate and the gear ring of the external gear component, and avoiding localized stress concentration caused by misalignment. The positioning holes also allow for quick locking of the component position.

[0013] On the other hand, this utility model provides a gearbox that includes the aforementioned transmission gear with integrated torque limiting protection function. Compared with the prior art, the gearbox of this utility model can achieve at least one of the following beneficial effects:

[0014] 1. It has an impact protection function, which can prevent damage to weak parts in the DHT (Dual Harmony Transmission) input shaft or transmission system due to impact torque.

[0015] 2. The transmission gears do not occupy extra space within the system, enabling a further lightweight design of the hybrid system's shaft system, reducing system costs and energy consumption.

[0016] 3. It has a wide range of applications and can also be applied to the electric drive system of pure electric vehicles.

[0017] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages will become apparent from the description or be learned by practicing the invention. The objectives and other advantages of this invention can be realized and obtained from the description and accompanying drawings, which are particularly pointed out. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0019] Figure 1 This is a schematic diagram of the transmission gear structure with integrated torque limiting protection function of this utility model;

[0020] Figure 2 This is a cross-sectional schematic diagram of the transmission gear structure with integrated torque limiting protection function of this utility model.

[0021] Figure 3 This is a schematic diagram of the friction plate in the transmission gear with integrated torque limiting protection function of this utility model.

[0022] Figure 4 This is a schematic diagram of the torque transmission disc in the transmission gear with integrated torque limiting protection function of this utility model.

[0023] Figure 5 This is a schematic diagram of the external gear component in the transmission gear with integrated torque limiting protection function of this utility model.

[0024] Figure 6 This is a schematic diagram of the keypad hub structure in the transmission gear with integrated torque limiting protection function of this utility model. Detailed Implementation

[0025] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0026] like Figures 1-4 As shown, this embodiment provides a transmission gear with integrated torque limiting protection function, including an external gear component 1, a torque limiter assembly, and an internal gear component 8, all of which are ring-shaped. The external gear component 1 is connected to the internal gear component 8 through the torque limiter assembly to resist torque. When there is a torque impact, the torque limiter assembly can slide relative to each other to buffer the torque transmission between the external gear component 1 and the internal gear component 8. According to this embodiment, the torque limiter assembly includes a friction plate 2, a torque transmission disk 3, and a cover plate 4. An external gear ring 11 is provided on the outer peripheral surface of the external gear component 1, and a first internal gear ring 12 is provided on the inner peripheral surface; the outer peripheral surface of the friction plate 2 is provided with teeth that mesh with the first internal gear ring 12; the torque transmission disk 3 is in contact with the friction plate 2, and the inner peripheral surface of the torque transmission disk 3 is provided with a connecting key 31 for resisting torque connection with the internal gear component 8; the cover plate 4 is used to provide axial pressure on the friction plate 2 and the torque transmission disk 3, the outer diameter of the friction plate 2 is larger than the outer diameter of the torque transmission disk 3, and the inner diameter of the friction plate 2 is larger than the inner diameter of the torque transmission disk 3.

[0027] To ensure that the friction plate 2 and the torque transmission disc 3 are pressed together, mounting grooves can be provided on both axial sides of the external gear component 1 for embedding the mounting cover plate 4. The cover plate 4 and the external gear component 1 are fixed together by rivets. The thickness and number of the friction plate 2 and the torque transmission disc 3 are set according to the depth of the mounting groove and the thickness of the external gear component 1, so that the mounting cover plates 4 on both sides are tightly attached to the sides of the friction plate 2 or the torque transmission disc 3, thereby pressing the friction plate 2 and the torque transmission disc 3 together.

[0028] In use, the connecting key 31 engages with the keyed internal gear component. The connecting key 31 can be a spline or other suitable known key. The torque transmission path is external gear component 1 → friction plate 2 → torque transmission disc 3 → internal gear component 8 → drive shaft; conversely, it can also be reversed. Compared to the transmission gears in the prior art, in this embodiment, when the transmission gear is subjected to a large impact torque, relative sliding will occur between the torque transmission disc 3 and the friction plate 2, thereby playing a role in slippage and torque limiting, and avoiding damage to the shaft. The torque transmission disc 3 can integrate the function of the internal gear component, that is, the torque transmission disc 3 is directly connected to the drive shaft for anti-torsional connection, thereby reducing the overall number of components.

[0029] For ease of assembly, the structure of the external gear component 1 can be optimized, requiring only one cover plate 4 to be installed. For example... Figure 5 As shown, a stepped hole 5 is axially formed in the middle of the external gear component 1. The stepped hole 5 includes a first hole section 51 and a second hole section 52. A first internal gear ring 12 is disposed on the hole wall of the second hole section 52, and a cover plate 4 is installed inside the first hole section 51. The diameter of the first hole section 51 is larger than the diameter of the second hole section 52.

[0030] The transmission gear in this embodiment also includes a pressure plate 6 and a diaphragm spring 7. The pressure plate 6 is used to press the friction plate 2 and the torque transmission plate 3. The diaphragm spring 7 is installed between the pressure plate 6 and the cover plate 4. With the pressure plate 6 and the diaphragm spring 7, the thickness of the friction plate 2 and the torque transmission plate 3 can be selected more flexibly. Moreover, due to the shock absorption and pressing effect of the diaphragm spring 7, the transmission is more stable, reliable and precise.

[0031] According to the preferred scheme, three friction plates 2 and two torque transmission disks 3 are arranged alternately. The alternating arrangement of friction plates 2 and torque transmission disks 3 forms multiple friction pairs. Each contact surface shares the total torque, significantly reducing the load pressure of a single-layer friction pair. Compared to a single pair of friction pairs, the force on each layer of the five-layer structure is reduced by approximately 60%, thereby reducing localized wear and heat accumulation. The number of friction plates 2 is one more than the number of torque transmission disks 3, allowing the friction plates 2 to be located on the innermost and outermost sides. When axial clamping force is applied through the cover plate 4 and pressure plate 6, the pressure can be evenly transmitted to all friction pairs, preventing uneven force distribution on the torque transmission disks 3 due to lack of support at both ends.

[0032] like Figure 6As shown, in this embodiment, the internal gear component 8 can be designed as a spline hub. The outer circumferential surface of the spline hub 8 is provided with an external spline 81 that meshes with the internal spline, and the inner circumferential surface of the spline hub 8 is provided with a second internal gear ring 82. In the embodiment using the spline hub 8, the torque transmission path is: external gear component 1 → multiple sets of friction plates 2 → torque transmission disc 3 → spline hub 8 → drive shaft. The spline hub 8 and the external gear component 1 have the same axial dimensions. The external spline 81 is located in the middle of the outer circumferential surface of the spline hub 8. Bearings 9 are also sleeved on the outer circumferential surface of the spline hub 8, and the bearings 9 are located on both sides of the external spline 81. Bearing seals are provided on the bearings 9.

[0033] like Figure 3 As shown, four positioning holes are provided at corresponding positions on the friction plate 2 and the external tooth component 1 for positioning and installing the friction plate 2.

[0034] This embodiment also provides a gearbox, which includes the transmission gear with integrated torque limiting protection function provided in this embodiment. The gearbox of this embodiment can be a dedicated gearbox for hybrid or pure electric vehicles, and its structure includes the following components: an input shaft: connected to the output end of a drive motor or engine, transmitting power to the torque limiting gear; the torque limiting gear in this embodiment; an output shaft: connected to the internal gear component 8 of the torque limiting gear via a spline, transmitting power to the wheel end; and a housing: integrating lubrication and heat dissipation channels, and having built-in bearing seats to fix the torque limiting gear and shaft system.

[0035] The transmission workflow in this embodiment is as follows:

[0036] Normal operating conditions (torque ≤ threshold):

[0037] The input shaft drives the external gear component 1 to rotate → the friction plate 2 rotates synchronously with the external gear component 1 → the torque transmission disc 3 rotates synchronously under the pressure of the friction plate 2 → the torque is transmitted to the internal gear component 8 via the internal spline 31 of the torque transmission disc → the output shaft drives the wheel. The diaphragm spring 7 provides a constant clamping force to ensure complete engagement of the friction pair.

[0038] Impact conditions (torque > threshold):

[0039] The impact torque at the wheel end is transmitted in reverse to the output shaft → the internal gear component 8 drives the torque transmission disk 3 to attempt to rotate at overspeed → the friction plate 2 and the external gear component 1 maintain their original rotation speed due to inertia → sliding friction is generated between the torque transmission disk 3 and the friction plate 2 → the sliding process consumes the impact energy, thereby limiting the torque transmitted to the input shaft.

[0040] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

[0041] List of reference numerals

[0042] 1 External gear component

[0043] 11 External gear ring

[0044] 12 First internal gear ring

[0045] 2 Friction Plates

[0046] 3. Transmit twist plate

[0047] 31 Connection Key

[0048] 4. Cover plate

[0049] 5-step hole

[0050] 51 First Hole Section

[0051] 52 Second Hole Section

[0052] 6 pressure plate

[0053] 7 Diaphragm Spring

[0054] 8. Internal gear components, keypad hub

[0055] 81 External spline

[0056] 82 Second Internal Gear Ring

[0057] 9 bearings.

Claims

1. A drive gear integrated with a torque limiter function, comprising an outer toothed part (1), a torque limiter assembly and an inner toothed part (8), all of which are ring-shaped, wherein The external gear component (1) is anti-torsionally connected to the internal gear component (8) through the torque limiting assembly. The torque limiting assembly has a friction plate (2), a torque transmission disk (3), and a cover plate (4). The inner circumferential surface of the external gear component (1) is provided with a first internal gear ring (12). The outer circumferential surface of the friction plate (2) is provided with teeth that mesh with the first internal gear ring (12). The torque transmission disk (3) is attached to the friction plate (2). The cover plate (4) is fixedly connected to the side of the external gear component (1) to provide axial pressure to the friction plate (2) and the torque transmission disk (3), so that the torque is transmitted between the external gear component (1) and the internal gear component (8) through the torque limiting assembly. When the torque exceeds a preset threshold, the friction plate (2) and the torque transmission disk (3) can slide relative to each other.

2. The torsion-limiting transmission gear integrated with a torsion-limiting protection function according to claim 1, characterized in that: The external gear component (1) has a stepped hole (5) axially formed in the middle. The stepped hole (5) includes a first hole section (51) and a second hole section (52). The first internal gear ring (12) is disposed on the hole wall of the second hole section (52). The cover plate (4) is installed in the first hole section (51).

3. The torsion-limiting transmission gear integrated with a torsion-limiting protection function according to claim 2, characterized in that: The torque limiter assembly also includes a pressure plate (6) and a diaphragm spring (7). The pressure plate (6) is used to press the friction plate (2) and the torque transmission plate (3). The diaphragm spring (7) is installed between the pressure plate (6) and the cover plate (4).

4. The torsion-limiting transmission gear with integrated torsion-limiting protection function of claim 2, wherein: Multiple friction plates (2) and multiple torque transmission discs (3) are provided respectively, and the friction plates (2) and the torque transmission discs (3) are arranged alternately.

5. The torsion-limiting transmission gear integrated with a torsion-limiting protection function according to claim 4, characterized in that: The number of friction plates (2) is one more than the number of transmission discs (3).

6. The integrated torque-limiting protection feature transmission gear of any one of claims 1 to 5, wherein: The transmission disc (3) has a connecting key (31), the internal gear component (8) is designed as a spline hub, the outer peripheral surface of the spline hub is provided with an external spline (81) that meshes with the connecting key (31), and the inner peripheral surface of the spline hub is provided with a second internal gear ring (82).

7. A drive gear integrated with a torque limiting protection function as claimed in claim 6, characterized in that: The spline hub and the external gear component (1) have the same axial dimensions. The external spline (81) is located in the middle of the outer peripheral surface of the spline hub. A bearing (9) is also sleeved on the outer peripheral surface of the spline hub, and the bearing (9) is located on both sides of the external spline (81).

8. The torsion-limiting transmission gear integrated with a torsion-limiting protection function according to any one of claims 1 to 5, characterized in that: The transmission disc (3) and the internal gear component (8) are an integral part.

9. The torsionally limiting and protecting drive gear of claim 1, wherein: The friction plate (2) and the external tooth component (1) have multiple positioning holes at corresponding positions.

10. A gearbox characterized in that, The transmission gear employs the integrated torque limiting protection function as described in any one of claims 1-9.

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