Variable limited slip dual mode differential

Abstract

The patent discloses a variable limit slip dual-mode differential technology, which is characterized by: using the locking and non-locking conversion technology of worm and gear reverse transmission to realize the full-time limit slip function of the differential, so that the differential is different from the traditional differential and obtains new characteristics and new applications: the car equipped with the differential has the overall superior performance of the car equipped with the Torsen differential, and does not have the single-wheel suspension failure problem, and is low in wear and energy consumption, maintenance-free and high in reliability, the differential can work in mechanical and electric control dual-mode control state at the same time, the electric control is accurate in usual, and the mechanical control is used as safety backup when the electric control fails, which is safe and reliable, and is the long-term pursuit of high-performance cars and the indispensable configuration of new energy cars.

Description

Technical Field

[0001] This invention relates to the fields of worm gear transmission technology and differential technology, specifically a technology that utilizes the locking and unlocking switching technology of worm gear reverse transmission to realize the all-time limited-slip function of a differential. Background Technology

[0002] The development of differentials has progressed through several stages: open differentials (advantages: simple structure, low cost, high reliability, good smoothness; disadvantages: no anti-slip), locking differentials (advantages: when locked, the left and right wheels rotate synchronously, extremely strong off-road capability; disadvantages: cannot turn when locked, can damage the transmission system), and Torsen differentials (advantages: purely mechanical, instantaneous response, reliable and durable, maintenance-free, automatically distributes torque when grip changes; disadvantages: complex structure, heavy weight, high cost; has a "torque sensing blind spot," may not lock when a single wheel is suspended in extreme conditions; state is immutable, continuously locked). There are various types of differentials, including those that lock even when there is a speed difference and no slippage; multi-plate differential LSDs (advantages: adjustable limited slip, fast response, wide applicability; disadvantages: overheating and performance degradation during long-term high-intensity use; requires precise control and is more expensive); and electronically controlled differentials (advantages: intelligent, active intervention, can pre-distribute power, integrated with ESP / TC and other systems, improving on-road handling limits; disadvantages: complex system, completely dependent on electronic systems and sensors, high cost, weak mechanical feel, and less reliable than mechanical differentials). Each type of differential has its own advantages, application scenarios, and disadvantages. Among them, the Torsen differential was once synonymous with high-performance, full-time four-wheel drive systems, especially when it was deeply integrated with Audi's quattro system. However, the Torsen differential also has fatal flaws, which limit its widespread application. In addition to the above-mentioned drawbacks, Torsen differentials also suffer from poor integration with electronic systems. Their purely mechanical structure makes it difficult to achieve refined and programmable collaborative control with the complex electronic systems of modern vehicles, such as ESP and traction control. With the development of automotive electronics and intelligence, as well as the requirements for energy conservation, emission reduction, and lightweighting, the application of Torsen differentials in new vehicles is decreasing.

[0003] This application is part of the applicant's series of inventions concerning "variable locking worm gear technology". The relevant basic technologies can be found in the invention patent applications filed on the same day [a variable locking worm gear mechanism (country: China, application date: 2026-04-24), hereinafter referred to as Patent A] and [a worm gear clutch (country: China, application date: 2026-04-24, application number: 2026105581992), hereinafter referred to as Patent B]. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, especially Torsen differentials, this invention provides a variable limited-slip dual-mode differential. Its core lies in the introduction of a state-controllable locking mechanism that can intelligently respond to the speed difference (the speed of the wheels on both sides of the vehicle or the speed of the front and rear axles) or external control signals, thereby realizing a smooth and controllable transition of the differential from free differential to full lock.

[0005] The technical solution of the present invention is as follows: A variable limited-slip dual-mode differential includes a differential housing, a drive shaft (41), a left output shaft (45), and a right output shaft (49). The key feature is that it is equipped with a state-controllable locking mechanism. This mechanism can dynamically switch between two states: "allowed differential" and "limited differential" based on the speed difference signal between the left and right output shafts or an external control signal.

[0006] To realize the above core concept, the present invention provides a variety of specific implementation methods, which are described below from three dimensions for ease of introduction.

[0007] A. Classified by the location of the locking mechanism: Indirect control type: The state-controllable locking mechanism is configured to act on the planetary gears of the differential; by controlling the rotation of the planetary gears, the speed difference between the left and right output shafts is indirectly limited; this is one of the main implementation methods of the present invention, which has the advantages of precise control and low impact on the transmission chain; Direct control type: The state-controllable locking mechanism acts as a clutch, with its input and output parts directly connected to the left and right output shafts, respectively. By controlling the engagement and disengagement of the clutch, the synchronization or differential speed of the two output shafts can be directly achieved. This method has a direct structure and a large locking force.

[0008] B. Classification based on the specific type of locking mechanism: Worm gear transmission pair: This is the preferred locking mechanism type of this invention; it can be further subdivided into: Variable locking worm gear mechanism: This mechanism achieves a change in state by moving the worm axially, switching it between a high-friction self-locking engagement zone and a low-friction non-self-locking engagement zone; the state switching can be automatically triggered by a purely mechanical speed difference signal, or it can be assisted or actively controlled by an electronic control signal. Dual worm gear clutch: It adopts two worm gear pairs with different lead angles (one self-locking and one non-self-locking), and selects one of them to participate in the operation through a switching device; its state switching is mainly controlled by external signals (manual or electronic control); The combination of a reduction gear and a resistance control motor: The resistance control motor applies a resistance torque to the input shaft of the reduction gear, thereby controlling the rotation of the planetary gear connected to it; this scheme is usually actively controlled by an electronic control signal. Centrifugal pendulum locking mechanism: Based on the webbing-sensitive locking mechanism principle in the vehicle seat belt retractor, in order to adapt to the high torque conditions of the differential, the diameter of the reel, the ratchet module and the housing material have all undergone structural reinforcement treatment, so that it can withstand a torque greater than the maximum driving torque of a single wheel of the vehicle.

[0009] The mechanism includes a spool, a centrifugal pendulum, and a ratchet and pawl assembly; the spool is configured to receive a rotational speed input from a planetary gear; the centrifugal pendulum is configured to swing outward against the return spring force when the rotational speed of the (planetary gear) exceeds a threshold, driving the ratchet and pawl to engage and prevent the spool from rotating.

[0010] This mechanism uses the centrifugal force generated by the centrifugal pendulum as its rotation speed increases to trigger the mechanical lock, which is a purely mechanical automatic triggering method. The mechanism can also be equipped with electrical control components to adjust its trigger threshold or achieve active triggering by electrical control signals.

[0011] The trigger threshold must be set so that the vehicle is in an unlocked state when it is not slipping (such as during normal turning).

[0012] C. Classification by control mode: Purely mechanical automatic control mode: The working state of the locking mechanism is automatically triggered (locking) and released (locking) by the mechanical structure based on the real-time speed difference signal; it has a rapid response and extremely high reliability, and is usually used as a safety backup. Active electronic control mode: The working state of the locking mechanism is actively and precisely controlled by the vehicle electronic control unit (ECU) based on external control signals (such as instructions from ESP and traction control system); it has a high degree of intelligence and can be deeply integrated with the whole vehicle electronic control system; Dual-mode control: Some solutions (such as variable locking worm gear mechanism) can simultaneously possess the above two control modes, achieving the highest safety and performance standards of "precise electrical control and mechanical backup", which is a safety redundancy solution.

[0013] The variable locking worm gear mechanism described above originates from patent A, and its specific structure is as follows: Figure 1 , 23. Based on the ordinary worm gear, configure one or more combinations of the following structures: First, extend the worm from one meshing area to at least two meshing areas, one of which is a low-friction area (4), which meshes with the worm gear in the opposite direction and does not self-lock, and the other is a high-friction area (3), which self-locks in the opposite direction; Second, add a rotary damper (13) to the worm to increase the resistance torque of the worm when needed; Third, add an end face ratchet pair (11, 12) to the worm to ensure that the worm cannot rotate when meshing; Fourth, add a damping motor (15) to increase the resistance torque of the worm when needed; Fifth, set a positioning spring (1, 2) to position the worm in a suitable meshing area; Sixth, set an electric control board (9, 10) to control the position of the worm, rotary damper and end face ratchet pair.

[0014] The working principle of the variable locking worm gear mechanism is as follows: Figure 1 When there is a speed difference between the left and right output shafts, the planetary gear (51) starts to rotate, driving the worm gear (6) connected to it to rotate; the locking trigger condition of the mechanism is proportional to the speed of the planetary gear / worm gear, that is, proportional to the speed difference between the left and right output shafts; when the worm gear speed is low, the positioning spring positions the worm gear in the initial position [low friction zone (4), the mechanism does not self-lock in reverse transmission], and the worm can rotate freely with the worm gear (idle). When the speed of the worm gear increases, when the axial force applied by the worm gear to the worm is greater than the force of the positioning spring, the worm is axially displaced to the high friction zone (3), and the mechanism self-locks / locks.

[0015] The reverse transmission refers to the transmission in which the worm gear is the driving wheel and the worm is the driven wheel. The following self-locking / non-self-locking and locking / non-locking refer to the state during reverse transmission. The self-locking, also called reverse self-locking, is a locking state that means that the worm gear mechanism can achieve reverse locking by itself without the action of external force, that is, the worm stops rotating. The non-self-locking, also called reverse non-self-locking, refers to the worm gear being in a state of obvious rotation.

[0016] When the worm wheel enters the locked state from one direction, because the back of the thread in the high friction area (3) is made of a low friction coefficient material (which does not self-lock when meshing with the worm wheel), the worm wheel will reverse and unlock the mechanism. Under the action of the positioning spring force, the worm will return to the initial position.

[0017] See Figure 2 , 3 The rotary damper (13) is used to strengthen or replace the high friction area, the end face ratchet pair (11, 12) is used to enhance the locking rigidity, and the axial movement of the worm can make both of them work. The electric control board (9, 10) is used in conjunction with or to replace the positioning spring (1, 2) to control the locking action of the worm gear; The damping motor (15) is used to replace the high friction zone, the rotary damper and the electric control board.

[0018] Without an electric control board and a damping motor, the above mechanism operates in a purely mechanical mode. With an electric control board and a damping motor, an electric control mode and a semi-locking function are added, thereby increasing the semi-limited slip condition of the differential.

[0019] The aforementioned dual worm gear clutch originates from patent B, see [link / reference]. Figure 4 , 5 One set is a reverse self-locking type, and the other is a reverse non-self-locking type. The two worm gears are fixed on one half-shaft (gear) of the differential, and the two worms are fixed on the other half-shaft (gear) of the differential. The meshing switching device is used to control the switching of the meshing of the two worm gears and worms.

[0020] The half-shafts refer to the left output shaft and the right output shaft.

[0021] The meshing switching device includes a lever fixing plate (28) (a rotatable seesaw for fixing two worm gears). The lever fixing plate is similar to a seesaw with a lever. There is a seesaw at each end of the worm gears (26, 30). The two ends of the seesaw are used to fix the worm gears, and the middle is used to rotatably fix them to the worm gear fixing bracket (27). The worm gear fixing bracket is fixed to the output shaft turntable (31). With this configuration, the lever fixing plate can control the meshing of the two worm gears. See Figure 4 The lever mounting plate can be manually controlled or electrically controlled.

[0022] The meshing switching device is used to switch the meshing of the worm gear pair, thereby changing whether the input shaft and output shaft are driven by a self-locking worm gear pair or a non-self-locking worm gear pair, thus changing the power transmission line.

[0023] Furthermore, by using a lever fixing plate, it is ensured that only one of the two worm gears can be engaged at any given time, and the engagement of the two gears can be changed at any time, thereby realizing the engagement and disengagement of the differential.

[0024] Furthermore, the entire device now functions as a differential, and the power torque can be transmitted via the input shaft – worm gear (or worm) – worm (or worm wheel) – output shaft.

[0025] Furthermore, to ensure smooth engagement (no gear jamming) of the two worm gears, accurate alignment of the threads on both sides of the worm must be guaranteed when it approaches the worm wheel. Therefore, we install gear pairs at one or both ends of the two worms. The meshing of these gears ensures the connection between the rotation of the two worms, thus making the worm meshing with the worm wheel act as a guide for the other worm, ensuring accurate alignment when switching to the other worm gear. See [link to relevant documentation]. Figure 5 .

[0026] The aforementioned variable locking worm gear mechanism clutch originates from patent B, see [link]. Figure 6 , 7 First, fix the worm gear on one half-shaft (output gear) of the differential, and fix the worm on the other half-shaft (output gear) of the differential. When the worm gear is locked, the worm does not rotate on its own, and the worm gear and the worm rotate synchronously around the common axis of the input half-shaft and the output half-shaft, and the differential is locked. When the worm gear is slipping (not locked), the worm gear can only rotate with the worm (slipping and spinning), and the differential is not locked.

[0027] Figure 6 The lead angle of the worm can be designed to be larger, so that the resistance and energy consumption of the worm wheel are smaller at low speeds. The worm wheel rotates with the worm in idle mode. When the speed of the worm wheel reaches the set value, the axial force of the worm increases and the worm begins to move significantly to the side of the axial force. At this time, the damper engagement area (14) on that side first engages with the rotary damper on the same side. The damper works and prevents the worm from rotating to lock. The locked state further increases the axial force and the movement of the worm also increases further until it engages with the end face ratchet pair on the same side. If the worm wheel in the locked state starts to rotate in the opposite direction, since the rotary damper is unidirectional, under the action of the positioning spring (1 or 2), the worm easily returns to the middle position, and the worm wheel and worm gear transmission pair returns to the idle state (non-self-locking). If the speed of the worm wheel rotating in the opposite direction increases to the set value, it enters the reverse locking state, and so on...

[0028] The above describes the working principle of the purely mechanical structure. When an electric control board (9, 10) is added, the left and right movement of the worm can be controlled more precisely, thus achieving a dual control function of mechanical + electric control in the worm gear transmission state. It also adds a semi-clutch function (semi-limited slip). The function of the end face ratchet pair is to improve the reliability of locking (rigid locking).

[0029] This solution has dual control functions, including mechanical and electrical control, and can realize functions such as low-speed differential disconnection, high-speed differential locking, and automatic disconnection when the drive shaft rotates in reverse.

[0030] The centrifugal pendulum locking mechanism is a mature solution widely used in webbing-sensitive (belt-sensing) locking mechanisms for automotive seat belts. It includes: a spool (core shaft) fixed to one end of the webbing and rotating as the webbing is pulled out / retracted; a weighted pendulum (inertia block) mounted on one end of the spool and swinging around its fulcrum; a return spring that keeps the pendulum in the retracted position under normal conditions; a cam fixed to the retractor housing; and a sliding pin and a rotating pawl that are linked to the cam.

[0031] The superior performance of this patented differential comes from: (i) the worm gear combination used in this differential, which does not rely on its own rotation torque to output power during reverse transmission, and whose worm is either idling or locked in most cases, thus making its power consumption almost zero; moreover, in the technical solution of this patent, the power of the input shaft is not transmitted to the output shaft by the worm's own rotation torque, but by the axial force of the worm (which is far from the center of the output shaft and forms the output torque on the output shaft) to the output shaft. The above two points enable the transmission efficiency of the variable limited slip dual-mode differential of this patent to reach the level of the locking differential; (ii) in the reduction mechanism + resistance control motor solution, the output power does not pass through the "reduction mechanism or resistance control motor", but through the planetary gear. The "reduction mechanism + resistance control motor" only changes the ratio of the output power on the two output shafts; (iii) the centrifugal pendulum locking mechanism solution is similar to the reduction mechanism + resistance control motor solution.

[0032] Compared with the prior art, the beneficial effects of this invention patent are: Achieving a Technological Breakthrough: This invention does not simply transplant existing technology, but rather utilizes its "dual-mode control + dynamic variable locking" characteristics to solve inherent problems in the differential field. Specifically, by introducing patents A and B, it achieves a breakthrough effect of "all-time limited slip + dual-mode control," which is unattainable by traditional fixed-state mechanisms. For example, it solves the industry pain points of Torsen differentials such as "torque sensing blind spot" and "difficulty in electronic control integration" (these pain points have existed since the inception of Torsen differentials), and achieves safety redundancy through "dual-mode control." The technological breakthrough is not immediately obvious, but the technological advantages are. This variable limited-slip dual-mode differential has the advantages of a dog clutch differential, and its engagement does not require synchronization. This variable limited-slip dual-mode differential combines the advantages of friction differentials with virtually no wear, resulting in a significantly extended service life. This variable limited-slip dual-mode differential has the advantages of an electromagnetic differential, but it also has no residual magnetism and almost no power consumption (it does not require power to maintain the clutch state).

[0033] When not locked, this variable limited-slip dual-mode differential performs the same as an open differential (high efficiency, good driving performance). When high speed differences require limited slip, the engagement of the limited slip does not require synchronization. When limited slip, its performance is the same as a locking differential (high efficiency, synchronized left and right wheel speeds, and extremely strong off-road capability). This variable limited-slip dual-mode differential combines the precision and intelligence of computer control with the safety of mechanical control. Its dual control performance can be online simultaneously, and its performance is stable and reliable under various working conditions, especially extreme conditions.

[0034] The performance comparison of the variable limited-slip dual-mode differential with other differentials is shown in the table below:

[0035] Note: The overall evaluation of the limited-slip differential is as follows: Differential #1: Unlimited slip; Differential No. 2: Good limited-slip performance; disadvantages: only mechanical limited-slip, cannot be integrated with electronic control, single wheel suspension failure, and certain frictional power consumption. Differential No. 3: Good limited-slip performance, no friction power consumption; Disadvantages: Only usable at low speeds, disabled at high speeds, no automatic switching. Differential No. 4: Good electronic limited-slip performance; disadvantages: frictional power consumption and thermal instability, not suitable for continuous long-term use. No. 5 differential: good electronic limited-slip performance; disadvantage: no mechanical limited-slip redundancy. No. 6 differential: good electronic limited-slip performance, applicable to the entire speed range, no friction power consumption; disadvantage: no mechanical control limited-slip redundancy. No. 7 differential: good electronic limited-slip performance, applicable to the entire speed range, no friction power consumption; disadvantage: no mechanical control limited-slip redundancy. No. 8 differential: mechanical automatic switching limited slip, precise electronic control, good limited slip performance, no friction power consumption, universal across the entire speed range, with mechanical control redundancy, and semi-limited slip function; No. 9 differential: mechanical automatic switching limited slip, precise electronic control, good limited slip performance, no friction power consumption, universal across the entire speed range, with mechanical control redundancy; disadvantage: no semi-limited slip function. No. 10 differential: mechanical automatic switching limited slip, precise electronic control, good limited slip performance, no friction power consumption, universal across the entire speed range, with mechanical control redundancy, and semi-limited slip function; Differential No. 11: Excellent electronic limited-slip performance, applicable across the entire speed range, and no frictional power consumption. Disadvantage: No mechanical limited-slip redundancy.

[0036] In summary, the beneficial effects of this invention are that it combines the advantages of open, locking, Torsen, and electronically controlled differentials, achieving a highly efficient, extremely low-wear, and intelligently controllable all-time limited-slip function. It is particularly suitable for new energy vehicles and high-performance vehicles (such as off-road vehicles, mining machinery / vehicles, emergency supply vehicles, and special vehicles) that have high requirements for reliability, response speed, low energy consumption, and intelligence.

[0037] Once differentials 8-10 in the table above are installed on a car, they can enable full-time four-wheel drive without increasing fuel consumption, achieving precise electronic control and mechanical triggering redundancy safety measures. Attached Figure Description

[0038] Figure 1 Schematic diagram of variable locking worm gear mechanism (two-way locking, mechanical type).

[0039] Figure 2 Schematic diagram of variable locking worm gear mechanism (two-way locking, mechanical + electric control).

[0040] Figure 3 Improved version (two-way self-locking, mechanical + electronic control).

[0041] Figure 4 Side view of a dual worm gear clutch.

[0042] Figure 5 A three-dimensional schematic diagram of a double worm gear clutch.

[0043] Figure 6 Variable locking worm gear clutch (front view) (two-way locking, mechanical + electronic control).

[0044] Figure 7 Variable locking worm gear clutch (side view).

[0045] Figure 8 Differential (variable locking worm gear mechanism controlling star gear).

[0046] Figure 9 Differential (clutch, center differential layout).

[0047] Figure 10 Differential (reducer controls star gear).

[0048] Figure 11 Differential (centrifugal pendulum locking mechanism).

[0049] Combined chart caption: 1—Left-side positioning spring (used to maintain the initial position of the worm gear and trigger movement in response to axial force); 2—Right-side positioning spring (same as above, symmetrically arranged); 3——High friction coefficient thread / high friction coefficient zone (3) (reverse self-locking when meshing with worm gear, used for locking state); 4——Intermediate low friction coefficient thread / low friction coefficient zone (4) (non-self-locking in reverse when meshing with worm gear, used in non-locking state); 5—Worm gear (core transmission component, axially movable to switch meshing zones); 6—Worn gear (connected to the input / output shaft, driving the worm or rotating synchronously with the worm); 9 – Left electric control panel (drives the worm gear to move in electric control mode, controls locking / unlocking); 10—Right electric control panel (same as above, symmetrically arranged); 11—Left end ratchet pair (rigid locking structure, preventing the worm from rotating when engaged); 12—Ratchet pair on the right end face (same as above, symmetrically arranged); 13 - Left and right rotary damper (one-way) (increases the rotational resistance of the worm gear, assists in half-clutching or locking); 14—The area on the worm that engages with the rotary damper (the part of the worm that contacts the rotary damper when it moves axially). 15 - Damping motor (actively increases worm gear resistance in electronic control mode, replacing or partially replacing the rotary damper); 16—Damping driven wheel (damping motor transmission component, linked with worm gear); 17—Damping drive wheel (damping motor output component, driving the damping driven wheel); 21 — Worm Gear 1 (the worm gear of a non-self-locking worm gear pair, connected to the input / output shaft); 22 — Worm Gear 2 (the worm gear of the self-locking worm gear pair, connected to the input / output shaft); 23 — Input shaft (power input component, connected to power sources such as engine / motor); 24—Gear 1 (large gear, linkage gear set component, connecting worm 1); 25 — Gear 2 (small gear, linkage gear set component, connecting worm 2); 26—Worm 2 (small lead angle, reverse self-locking, corresponding to self-locking worm gear pair); 27—Worm gear fixing bracket (fixed to the output shaft turntable, supporting the lever fixing plate); 28—Lever fixing plate (“seesaw” structure, linking two worm gears to switch engagement); 29—Seesaw rotation axis (rotation fulcrum of lever fixing plate, fixed to worm gear fixing frame); 30—Worm 1 (large lead angle, reverse non-self-locking, corresponding to non-self-locking worm gear pair); 31—Output shaft turntable (connects the output shaft and supports the worm gear fixing bracket); 32 — Output shaft (power output component, connected to the load) 41 — Drive shaft; 42 — Drive gear; 43 — Driven gear (planetary gear carrier); 44 — Left half-shaft gear; 45 – Left output shaft; 46 — Worm gear (in the embodiment of the webbing-sensitive locking mechanism); 47 — Worm gear (in the embodiment of the webbing-sensitive locking mechanism); 48 — Right half-shaft gear; 49 — Right output shaft; 50 — Variable locking worm gear mechanism (low-pass, bidirectional locking, mechanical + electric control). 51 — Planetary gear; 55 — Intermediate clutch (variable locking worm gear mechanism or double worm gear pair); 57 — Speed ​​reducer; 58 — Reducer output gear (low speed end); 59 — Reducer input gear (high-speed end); 60 — Resistance-controlled motor; 61—— Centrifugal pendulum locking mechanism (clockwise locking); 62—— Centrifugal pendulum locking mechanism (counterclockwise locking). Detailed Implementation

[0050] Terminology definition: Locked state: The worm gear rotation is completely suppressed, and the mechanism cannot reverse the transmission; In the unlocked state: the worm gear can rotate freely, and the reverse transmission of the mechanism is smooth; Semi-locked / semi-clutch / semi-limited slip state: The worm gear speed is significantly reduced but not completely stopped, and the mechanism transmits part of the torque; this state is usually achieved by controlling the rotational damper (13) to engage while the end face ratchet pair (11,12) is not engaged, or it can be achieved by controlling the resistance torque through the damping motor.

[0051] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can easily implement the present invention.

[0052] Example 1 (corresponding to claims 2, 4, 5, 10, 11): Indirect control scheme and direct control scheme for the "variable locking worm gear mechanism" This embodiment of the variable limited-slip dual-mode differential includes a drive shaft (41), a drive gear (42), a driven gear (43), left and right half-shaft gears (44, 48), left and right output shafts (45, 49), planetary gears (51), and a variable locking worm gear mechanism (50) (low-pass, bidirectional locking, mechanical + electronic control). This embodiment is a technical solution where the variable locking worm gear mechanism indirectly controls the differential output shaft through planetary gears, enabling low-pass and high-speed differential locking, and is compatible with both mechanical and electronic control methods. See Figure 8 The settings are as follows.

[0053] Figure 8In this embodiment, the variable limited-slip dual-mode differential consists of multiple variable locking worm gear mechanisms (50) and an open differential. We connect a variable locking worm gear mechanism (50) to the outside of each planetary gear in the open differential. The worm wheel (6) of the variable locking worm gear mechanism (50) is connected to the planetary gear (51). The worm (5) is supported in a bracket by bearings. The bracket is fixed on the planetary gear carrier (i.e., the driven wheel 43). This installation method makes the worm (5) The worm (5) revolves at the same speed as the planetary gear carrier; when there is no speed difference between the left and right gears, there is no relative rotation between the worm (5) and the worm wheel (6); when there is a speed difference, the rotation of the planetary gear (51) will be converted into the rotation of the worm wheel (6) relative to the worm (5), thereby driving the locking mechanism. The axis of the worm (5) is parallel to the axis of the driven gear (i.e., the axis of revolution of the planetary gear carrier). The left and right rotation dampers (13) are fixed on the planetary gear carrier, and the outer sides of the ratchet pair (11, 12) are fixed on the planetary gear carrier.

[0054] Assuming the variable limited-slip dual-mode differential in this embodiment is used on the front or rear beam of a car, since the rotational speed of the planetary gear / worm gear is half the difference in rotational speed between the left and right output shafts, when both wheels do not slip, the difference in rotational speed between the left and right output shafts is not large, and the planetary gear / worm gear can easily drive the worm to rotate (rotate on its own, spin freely); when a single wheel slips, the above speed difference increases, the worm gear speed increases, and the worm gear (6) applies a greater axial force to the worm. When this force exceeds the set value of the positioning springs (1, 2), the worm begins to move significantly to the side of the axial force. At this time, the damper engagement area (14) on that side first engages with the rotary damper (13) on the same side, and the damper on that side plays a role in The action prevents the worm from rotating to almost a stop. At this time, the worm and the worm wheel hardly rotate (locked). The locked state further increases the axial force and the movement of the worm further increases until the ratchet pair on the same side engages (absolute lock). In the locked state, if the planetary gear / worm wheel starts to rotate in the opposite direction, due to the one-way rotation damper having no resistance in the reverse direction, under the action of the positioning spring (1, 2), the worm (6) easily returns to the middle meshing position, and the worm wheel and worm gear transmission pair returns to the non-locked state (empty rotation or no rotation). If the worm wheel rotates in the opposite direction and the rotation speed further increases to the set value, it enters the reverse lock state, and so on...

[0055] When the planetary gear (51) is locked, the left and right output shafts (45, 49) and the driven wheel (43) rotate synchronously to lock the differential lock. Conversely, when the planetary gear is not locked, the differential lock is unlocked.

[0056] The above describes the working principle of the purely mechanical structure. When an electric control board (9, 10) is added, the reverse transmission state of the worm gear can be controlled more intelligently and precisely under the control of the vehicle's central processing unit (ECU), achieving the dual control purpose of mechanical + electric control. The electric control is used for normal driving, and the mechanical control is used for auxiliary control when the electric control fails. The function of the end face ratchet pair is to improve the reliability of locking.

[0057] Mechanical automatic mode: When the speed difference between the left and right wheels is small → the speed of the planetary gear (51) and worm gear (6) is low → the axial force of the worm is less than the preload of the spring (1,2) → the worm is located in the low friction zone (4) and idles (differential speed is allowed); when the speed difference increases → the speed of the worm gear increases → the axial force overcomes the spring force → the worm moves axially to the high friction zone (3) or engages with the damper (13) / ratchet (11,12) → the worm rotation is suppressed → the worm gear and planetary gear are locked (differential speed is limited).

[0058] Electric control mode: The electric control board (9, 10) can actively drive the worm gear to move axially based on the ECU signal to achieve predictive locking or unlocking. In addition to unlimited slip and full limit, it can also add "semi-limited slip" (corresponding to the semi-locked state of the variable locking worm gear mechanism).

[0059] This embodiment is a dual-mode control scheme that combines "purely mechanical automatic triggering" and "electronic active control"; In this embodiment, the worm gear is the actuator of the planetary gear controller, and the worm and positioning spring are the control mechanisms of the planetary gear controller.

[0060] Example 2 (corresponding to claims 3, 5, 10, 11): "Variable locking worm gear mechanism" as a direct clutch See Figure 2 , 4 5, 9. The variable limited-slip dual-mode differential in this embodiment includes a drive shaft (41), a drive gear (42), a driven gear (43), left and right half-shaft gears (44, 48), left and right output shafts (45, 49), a planetary gear (51), and an intermediate clutch (55).

[0061] In this embodiment, the differential is mainly applied to the central differential.

[0062] This embodiment provides a solution that uses a "variable locking worm gear mechanism" as a clutch, directly connected between the left and right output shafts of the differential. (See reference for details.) Figure 9 The arrangement principle is shown.

[0063] In this scheme, the worm wheel of the "variable locking worm gear mechanism" is fixedly connected to one side output shaft (or the gear connected to it), and the worm is fixedly connected to the other side output shaft (or the gear connected to it), so that the mechanism is directly connected between the left and right output shafts.

[0064] In this embodiment, as a direct clutch, the speed difference between the left and right output shafts directly acts on the variable locking worm gear mechanism. When the speed difference reaches a threshold, the axial force generated inside the mechanism will overcome the preload of the positioning spring, thereby achieving pure mechanical automatic triggering and locking. Its triggering mechanism is essentially the same as that in Embodiment 1, which uses the sensing of the speed difference of the planetary gears.

[0065] Its working principle is the same as that of Example 1: when the speed difference between the left and right output shafts reaches the set threshold, the mechanism can be automatically triggered to lock by pure mechanical means; or it can be actively controlled by the electronic control unit (ECU) to lock and unlock according to the signal; when locked, the left and right output shafts are rigidly connected through the mechanism, and the differential function is prohibited.

[0066] Features of this embodiment: During normal full-time four-wheel drive, the differential lock is open, and both the front and rear wheels are powered. If the front two wheels or the rear two wheels slip simultaneously, the differential locks to ensure that the wheels that are not slipping are powered. For the differential's limited slip, the computer control is more precise and the mechanical control is more reliable (safety redundancy). The differential has high transmission efficiency, requires no maintenance, and has a long service life.

[0067] Example 3 (corresponding to claims 3, 6, 11): Direct control scheme for a "dual worm gear clutch" See Figure 2 , 4 5, 9. The variable limited-slip dual-mode differential in this embodiment includes a drive shaft (41), a drive gear (42), a driven gear (43), left and right half-shaft gears (44, 48), left and right output shafts (45, 49), a planetary gear (51), and an intermediate clutch (55).

[0068] In this embodiment, the differential is mainly applied to the central differential.

[0069] This embodiment provides a solution for directly connecting a "dual worm gear clutch" between the left and right output shafts of a differential; In this scheme, the input and output parts of the two sets of worm gears of the "dual worm gear clutch" are respectively connected to the left and right output shafts of the differential (or the gears connected to them); Its operation is entirely controlled by external signals to switch the meshing of the two worm gears through the lever fixing plate (28), thereby realizing the switching between the two states of "self-locking transmission" and "non-self-locking transmission". This switching action depends on external manual or electric control signals, so its main control mode is electric active control.

[0070] Features of this embodiment: During normal full-time four-wheel drive, the differential lock is open, and both the front and rear wheels are powered. If the front two wheels or the rear two wheels slip simultaneously, the differential locks to ensure that the wheels that are not slipping are powered. The computer control of the differential's limited slip is more precise. The differential has high transmission efficiency, requires no maintenance, and has a long service life.

[0071] Example 4 (corresponding to claims 2, 7, 11): Indirect control scheme of "reduction mechanism + resistance control motor" The variable limited-slip dual-mode differential in this embodiment includes a drive shaft (41), a drive gear (42), a driven gear (43), left and right half-shaft gears (44, 48), left and right output shafts (45, 49), planetary gears (51), a reducer (57), and a resistance control motor. In this embodiment, the resistance control motor indirectly controls the differential output shaft through the reducer and planetary gears. See Figure 10 The settings are as follows: Figure 10 In this embodiment, the variable limited slip dual-mode differential consists of a reducer (57), a resistance control motor (60), and an open differential. We connect a reducer (57) to the outside of each planetary gear of the open differential. The output gear (58) of the reducer is connected to the planetary gear (51), and the input gear (59) is connected to the resistance control motor (60). The reducer and the resistance control motor are mounted on the planetary gear carrier.

[0072] Assuming that the variable limited-slip dual-mode differential in this embodiment is used on the front and rear beams of a car, when the wheels on both sides do not slip, the speed difference between the left and right output shafts is not large, the resistance control motor (60) is de-energized and there is no resistance torque, and the planetary gears and reducers can idle effortlessly; when a single wheel slips, the car's ECU sends a signal to the resistance control motor, the resistance control motor starts, locks the reducer input shaft, locks the planetary gears through the reducer, the planetary gears (51) are locked, then the left and right output shafts (45, 49) and the driven wheel (43) rotate synchronously, realizing the locking of the differential lock; otherwise, the planetary gears are not locked, and the differential lock is released.

[0073] This embodiment illustrates the working principle of electric control. The reducer output gear serves as the actuator of the planetary gear controller, and the resistance control motor serves as the control mechanism of the planetary gear controller.

[0074] In this embodiment, the action of the resistance control motor (60) depends entirely on receiving the "external control signal" from the vehicle ECU. It does not have a mechanical structure that can sense the speed difference and trigger automatically. This is a typical electronic active control scheme.

[0075] Example 5 (corresponding to claims 2, 8, 10, 11): Indirect control scheme for "centrifugal pendulum locking mechanism" In this embodiment, the "centrifugal pendulum locking mechanism" that senses the "webbing pull-out acceleration" is used to sense the "rotational angular acceleration of the planetary gears" and is applied to the differential.

[0076] The core of the mechanism lies in using a centrifugal pendulum to sense the angular acceleration of the spool rotation; when applied to a differential, the rotation of the planetary gears is equivalent to the rotation of the spool, and their physical sensing principles are the same; by setting up a pair of such mechanisms that respond to forward and reverse rotation respectively, bidirectional locking can be achieved.

[0077] The variable limited-slip dual-mode differential in this embodiment includes a drive shaft (41), a drive gear (42), a driven gear (43), left and right half-shaft gears (44, 48), left and right output shafts (45, 49), planetary gears (51), and a centrifugal pendulum locking mechanism (61, 62) (low-pass, bidirectional locking, mechanical). This embodiment is a technical solution where the centrifugal pendulum locking mechanism indirectly controls the differential output shaft through planetary gears, enabling low-pass and high-speed differential locking, and is compatible with both mechanical and electronic control types. See Figure 11 The settings are as follows.

[0078] Figure 11 In this embodiment, the variable limited slip dual-mode differential consists of a centrifugal pendulum locking mechanism (61, 62) and an open differential. We connect a centrifugal pendulum locking mechanism (61) to one side of a pair of planetary gears in the open differential, and a centrifugal pendulum locking mechanism (62) to the other side. The spool (spindle) of the centrifugal pendulum locking mechanism is connected to the planetary gear (51), and the cam is indirectly and rotatably fixed on the driven wheel (43).

[0079] Assuming the variable limited-slip dual-mode differential in this embodiment is used on the front or rear beam of a car, when both wheels are not slipping, the speed difference between the left and right output shafts is small, the reel speed is slow, the centrifugal force generated by the rocker arm is small, and it is held by the return spring and does not contact the cam. The planetary gear / reel can rotate effortlessly and idle. When a single wheel slips, the speed difference increases, the reel rotates at high speed, and the rocker arm swings outward significantly under the action of centrifugal force, thereby triggering locking and mechanical linkage. The end of the rocker arm swings outward and pushes the cam, and the cam drives the rotating pawl to rotate through the sliding pin. At this time, the rotating pawl gets into the ratchet teeth fixed to the reel, and the reel cannot continue to rotate in the pull-out direction, and finally locks.

[0080] In the locked state, if the planetary gear / spindle speed decreases, the centrifugal force generated by the rocker arm is small and is pulled by the return spring, not contacting the cam. The planetary gear / spindle can rotate effortlessly or idle. At this time, if the planetary gear / spindle starts to accelerate and rotate in the opposite direction, the mechanism enters the reverse locking state, and so on...

[0081] When the planetary gear (51) is locked, the left and right output shafts (45, 49) and the driven wheel (43) rotate synchronously to lock the differential lock. Conversely, when the planetary gear is not locked, the differential lock is unlocked.

[0082] Its purely mechanical automatic triggering process: small speed difference → slow reel speed → small centrifugal pendulum force → no locking; large speed difference → high reel speed → centrifugal force triggers mechanical locking; this is a purely "mechanical automatic control mode".

[0083] The above describes the working principle of a purely mechanical structure. In this embodiment, the scroll is the actuator of the planetary gear controller, and the return spring, rotating pawl, and ratchet teeth are the control mechanisms of the planetary gear controller.

[0084] The stiffness of the return spring is calibrated to match the locking threshold with the speed difference when the vehicle is turning normally, thus avoiding false triggering.

[0085] This example can also be upgraded to "electronic active control" by adding electronic control components (such as an electromagnetic regulator) to adjust the lock-up threshold.

Claims

1. A variable limited-slip dual-mode differential, comprising a differential housing, a drive shaft (41), a left output shaft (45), and a right output shaft (49), characterized in that, Also includes: A state-controllable locking mechanism is disposed inside the differential; The state-controllable locking mechanism is configured such that its operating state can switch between a state that allows differential speed and a state that restricts differential speed, based on the speed difference signal between the left and right output shafts or an external control signal.

2. The variable limited-slip dual-mode differential according to claim 1, characterized in that, The state-controllable locking mechanism acts on the planetary gear (51) of the differential, and achieves limited slip by controlling the rotation of the planetary gear.

3. The variable limited-slip dual-mode differential according to claim 1, characterized in that, The state-controllable locking mechanism acts as a clutch, with its input and output parts connected to the left and right output shafts, respectively.

4. The variable limited-slip dual-mode differential according to claims 2 and 3, characterized in that, The state-controllable locking mechanism is a worm gear transmission pair.

5. The variable limited-slip dual-mode differential according to claim 4, characterized in that, The worm gear transmission pair is a variable locking worm gear mechanism.

6. The variable limited-slip dual-mode differential according to claim 4, characterized in that, The worm gear transmission pair is a double worm gear clutch.

7. The variable limited-slip dual-mode differential according to claim 2, characterized in that, The state-controllable locking mechanism includes a deceleration mechanism and a resistance control motor.

8. The variable limited-slip dual-mode differential according to claim 2, characterized in that, The state-controllable locking mechanism is a centrifugal pendulum locking mechanism.

9. The variable limited-slip dual-mode differential according to claim 8, characterized in that, The centrifugal pendulum locking mechanism is based on the webbing-sensitive locking mechanism principle in the vehicle seat belt retractor, and is structurally reinforced to adapt to the vehicle's driving force load; preferably, the mechanism also includes an electronic control component for adjusting its locking trigger threshold or actively triggering the locking.

10. The variable limited-slip dual-mode differential according to any one of the preceding claims, characterized in that, The switching of the working state is automatically triggered by the purely mechanical structure based on the speed difference signal.

11. The variable limited-slip dual-mode differential according to any one of the preceding claims, characterized in that, The switching of the operating state is at least partially controlled by the electronic control unit based on the external control signal.

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