Inertial and differential continuously variable transmission

Abstract

The present invention describes an inertial and differential continuously variable transmission (T) capable of transmitting power from an engine to the wheels of a vehicle, resulting in a CVT-type automatic transmission, in which the speed and the torque at the wheels are controlled as a function of output load, power generated by the engine and the instantaneous speed of the vehicle. The automatic transmission (T) comprises a planetary reduction gear (220), a differential (270) and a modified torque converter (400), which does not transfer power but multiplies torque and determines the appropriate gear ratios, functioning as an inertial sensor. These components are assembled in such a way that they do not require locks for a planetary reduction to function correctly.

Description

INERTIAL AND DIFFERENTIAL CONTINUOUSLY VARIABLE TRANSMISSION FIELD OF INVENTION

[0001] The present invention falls within the field of application of gear systems for transmitting rotary motion with a transmission ratio. More specifically, the present invention describes a system for transmitting power from a vehicle's engine to its wheels in a continuously variable manner, located between the vehicle's drive axle and the driven axle. DESCRIPTION OF THE STATE OF THE TECHNIQUE

[0002] A system of gears designed to transmit a vehicle's power to its wheels is known as a transmission or gearbox. The main types of vehicle transmissions are manual transmissions and automatic transmissions, the latter of which can be either a CVT (Continuously Variable Transmission) or a continuously variable transmission.

[0003] Manual transmissions are the most common type of transmission and work with gears of different sizes, which are engaged and disengaged individually by the driver, requiring a pedal to operate the clutch and presenting a set of five or more gears in automotive vehicles.

[0004] Automatic transmissions offer greater driving comfort. They use a torque converter to transfer engine power to the transmission and an (electro)hydraulic system that actuates planetary gears, which are always interconnected. In this type of transmission, gear changes (gear ratios) are controlled by electro-electronic sensors.

[0005] CVT automatic transmissions simulate infinite gear ratios. This transmission uses a set of belts connected by two variable-size pulleys. Cones, toroids, and other ingenious solutions are also used to transmit power in a continuously variable manner to the wheels, setting the vehicle in motion.

[0006] In vehicles equipped with manual transmissions, the need for the driver to select the appropriate gear can make driving a tiring task, but it can provide faster shift responses compared to automatic transmissions. For vehicles equipped with standard automatic or CVT transmissions, the responses are not as quick, but the driving comfort is much greater. larger. Current CVT transmissions are made up of variable-geometry parts and use friction to transmit power. Because they rely on friction, they are less reliable or efficient than gear-based transmissions. Another drawback of CVTs is the slow process of selecting the ideal gear ratio for each situation, which relies on complex and expensive sensor systems and electronic circuits.

[0007] The present invention presents an alternative to overcome the inconveniences still present in the prior art, as it allows for comfortable driving with all the benefits of a CVT, eliminating the problems related to frictional power transfer, in a simple manner and offering instant response, with the gear ratio based on the vehicle's inertia. It also presents high efficiency compared to prior art automatic transmissions, being able to operate without on-board electronics, with low-complexity mechanical components, smaller size and weight, and, consequently, with lower manufacturing and maintenance costs than traditional systems. STATE OF THE ART REFERENCES

[0008] The state of the art mentions some documents with multiple solutions to the problem related to the discomfort caused by constant manual gear changes, or by the slow responses of vehicles equipped with traditional automatic or CVT transmissions.

[0009] Document BR MU 8500006-0 (André Luis A. Ribeiro) describes a biarticulated electromagnetic mechanism for semi-automatic transmissions, which aims to increase comfort in gear changes without compromising speed recovery, being particularly applied to motorcycles.

[0010] Document US 6892599 (Kongsberg Automotive ASA) describes a manual transmission containing hydraulic cylinders that facilitate gear engagement and disengagement, partially alleviating the discomfort of constant gear changes.

[0011] Document CA 2736931 (Automatic Transmission, LTD) describes an automatic transmission that uses two or more planetary gear stages to shift gears automatically, eliminating the need for disengagement and control equipment. This transmission, however, does not solve the problem of delayed gear shifts.

[0012] Document US 7951039 (GM Global Technology Operations LLC) describes An automatic transmission with eight gears, which engage with small variations in engine torque. This technology aims to improve response by increasing the number of gear ratios.

[0013] Document BR PI1106964-3 (Alan Miranda Monteiro de Lima) describes an inertial continuously variable automatic transmission, whose gearshift control is based on engine torque and vehicle speed. This system requires a lock for the reduction system to operate, which reduces its efficiency.

[0014] As can be seen from the above references, the state of the art still lacks an automatic transmission, of the CVT type, which presents low complexity, simplified construction and consequently affordable cost, with the gear ratio based on the vehicle's inertia and which presents an efficiency gain that justifies its adoption. SUMMARY OF THE INVENTION

[0015] The present invention describes an inertial continuously variable transmission and differential capable of transmitting engine power to the wheels of a vehicle, resulting in a CVT type automatic transmission, in which the control of speed and torque at the wheels is a function of the output load, the power generated by the engine and the instantaneous speed of the vehicle.

[0016] The aforementioned automatic transmission comprises a planetary reduction gear, a differential, and a modified torque converter, which doesn't transfer power but rather multiplies torque and determines appropriate gear ratios, acting as an inertial sensor. These components are assembled in such a way that locks are not required for the planetary reduction gear to function properly.

[0017] With this configuration, the torque balance between the output shaft and the turbine of the modified torque converter makes this transmission function like a CVT. This torque / speed balance between the output shaft and the turbine is determined by the instantaneous load at the output (inertia) and the power generated by the engine, and the system is constantly naturally fed back by the vehicle's instantaneous inertia. DESCRIPTION OF FIGURES

[0018] In order to facilitate the understanding of the inertial and differential continuously variable transmission, which is the object of the present invention, the attached figures, described below, illustrate representations of possible embodiments thereof, namely: Figure 1 - shows a three-dimensional external side view of the transmission that is the object of the present invention, including the input shaft, the external housing, the modified torque converter and the output shaft; Figure 2 - shows a three-dimensional perspective view of the transmission that is the object of the present invention, with the input shaft in the foreground, without showing the side area of ​​the external housing, thus allowing the visualization of the components housed inside the transmission; Figure 3 - shows a three-dimensional perspective view of the transmission that is the object of the present invention, with the output shaft in the foreground, without showing the side area of ​​the external housing, thus allowing the visualization of the components housed inside the transmission; Figure 4 - shows an exploded perspective three-dimensional view of the transmission components, without showing the side area of ​​the outer casing; Figure 5 - shows an exploded three-dimensional perspective view of the modified torque converter with the housing in the foreground; Figure 6 - shows an exploded three-dimensional perspective view of the modified torque converter with the turbine in the foreground; Figure 7 - shows a flowchart indicating the path of the power, generated by the engine, in the transmission that is the object of this invention; and Figure 8 - shows a graph demonstrating an example of the behavior of the rotation of the output shaft of the inertial and differential continuously variable transmission, which is the object of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention, which may be better understood with the aid of the attached figures, which are an integral part of this report, describes a Continuously Variable Inertial and Differential Transmission (T) capable of transmitting engine power to the wheels of a vehicle, operating as a CVT type automatic transmission, in which the control of the speed and torque at the wheels is balanced according to the output load, the power generated by the engine and the instantaneous speed of the vehicle.

[0020] The aforementioned Continuously Variable Inertial and Differential Transmission (T), object of the present invention, comprises: - an input shaft (100), which receives power from the engine and the vehicle's common torque converter; - an external housing (200), with a substantially cylindrical shape, formed by a front area (200a), which is pierced by the input shaft (100), a side area (200b) and a rear area (200c), which in turn comprises the following components, immersed in lubricating oil: - a sun gear (210), directly connected to the input shaft (100); - three planetary gears (220), connected to the sun gear (210) and receiving power from it; - a support (230), fixed to the front area (200a) of the external housing (200), which serves as support for the three planetary gears (220); - a ring gear (240), smooth on its outer face and toothed on its inner face, which accommodates the three planetary gears (220) and the sun gear (210) inside; - a cover (250), which serves as a cover for the ring gear (240) and has movement in solidarity with it; - an output gear of the ring gear (260), which is fixed to the cover (250) of the ring gear (240) and has movement in solidarity with it; - a differential (270), in which one of its 4 gears is the output gear of the ring gear (260); - a differential support (280), which is fixed to the rear area (200c) of the external housing (200), and has movement independent of the ring gear (240); - an output shaft (300), which is fixed to one of the 4 differential gears (270), exiting through the rear area (200c) of the external casing (200) and presenting independent movement from it; - a modified torque converter (400) comprising, in turn: - a housing (405), which is fixed to the rear area (200c) of the outer housing (200); - a turbine (410), which is fixed to the casing (405) and, consequently, the rear area (200c) of the external casing (200), presenting movement in solidarity with such components; - a pump (430), which is attached to the output shaft (300); - a stator (420), located between the turbine (410) and the pump (430), responsible for redirecting the hydraulic fluid that comes out of the turbine (410) in the direction of rotation of the pump (430), remaining fixed to the vehicle's casing; and - optionally, a lock-up (440), which performs the physical coupling between the casing (405), the turbine (410) and the pump (430) when they are rotating at cruising speed, allowing them to rotate together without slipping between them.

[0021] The modified torque converter (400), object of the present invention, presents an innovative design being crossed in its entire length by the output shaft (300), which rotates freely inside it and is fixed only to the pump (430), which is positioned in the center of the device, and the turbine (410) is coupled peripherally to the housing (405), presenting movement in solidarity with it. This represents a total contrast to traditional torque converters, which have a sealed end and where it is the pump that is coupled to the housing.

[0022] The torque / speed balance between the output shaft (300) and the turbine (410) is carried out according to the instantaneous load at the output (inertia) and the power generated by the engine, and at all times the Inertial and Differential Continuously Variable Transmission (T) system is naturally fed back by the instantaneous inertia of the vehicle.

[0023] As exemplified in Figure 7, the aforementioned system feedback occurs in the following sequence: - the power from the engine accesses the transmission (T) via the input shaft (100); - the sun gear (210), which is directly connected to the input shaft (100), transfers the received power to the planetary gears (220); - the planetary gears (220) pass the power to the ring gear (240); - the ring gear (240), in turn, rotates in the opposite direction to the input shaft (100), and passes the power to the ring gear output gear (260); - the ring gear output gear (260) rotates the differential gears (270); - the differential (270) reverses the received rotation and transfers the power to the output shaft (300); - the output shaft (300) turns the vehicle wheels and the pump (430) of the modified torque converter (400) at the same time, since the pump (430) is fixed to the output shaft (300); - the pump (430) of the modified torque converter (400) drives the turbine (410) of the modified torque converter (400), which rotates the outer housing (200), which rotates the differential carrier (280), causing the differential (270) to rotate; and - the differential (270) divides the power between the output gear of the ring gear (260) and the output shaft (300), decreasing the rotation of the ring gear (240) in the opposite direction to the input shaft (100), thus increasing the rotation of the output shaft (300).

[0024] Power passes through the Inertial Continuously Variable Transmission and Differential (T) via the planetary gears (220) and the differential (270). The modified torque converter (400) acts as an inertial sensor, since the response of the hydraulic fluid (the torque converter fluid responsible for the pump transmitting power to the turbine) is slower than that of the gears. In other words, the gears respond immediately and the hydraulic fluid responds delayed. If the hydraulic fluid responded immediately, the same as the gears, this transmission would be a single-ratio transmission, 1:1.

[0025] The modified torque converter (400) transforms torque into speed or speed into torque, depending on the vehicle's inertia and engine power. If the output load is high, most of the torque goes directly to the wheels and the vehicle is in low gear, and if the load is low, some of the torque goes to the pump (430) and turbine (410) of the modified torque converter (400), and the vehicle is in high gear.As the power passes through the gears, and the pump (430) and turbine (410) of the modified torque converter (400) are at the output, with the pump (430) welded to the output shaft (300) and turbine (410) welded to the outer casing (200), which also rotates the output shaft (300); even with the turbine (410) rotating much slower than the pump (430), we will have rotation and torque at the output, but we will still have the torque multiplication, so we will have the efficiency of the gears plus the multiplication of the torque of the pump (430) by the turbine (410) of the modified torque converter (400), reaching an efficiency not found in traditional transmission systems.

[0026] The power generated by the engine enters the system through the input shaft (100) and the sun gear (210), and has its rotation reduced and its torque increased by the planetary gears (220), being transmitted by the ring gear (240) and to the differential (270) via the output gear of the ring gear (260). The differential (270) in turn transmits the power to the output shaft (300), which carries the power to the wheels and / or to the pump (430) of the modified torque converter (400).

[0027] The torque will thus flow to where it is easiest, so when we have excess torque at the wheels, the output shaft (300) starts to transfer part of the torque (what is in excess) to the pump (430) of the modified torque converter (400), which starts to turn the turbine (410), and as this is fixed to the external casing (200), it also starts to turn, turning the differential support (280), which turns the output shaft (300), feeding back into the system and changing gears according to the output load and the engine power.

[0028] The result of this inertial feedback can be speed, torque, or a combination of speed and torque, depending on the vehicle's inertia and engine power. This succession of power transfer in the Continuously Variable Inertial Transmission (CVT) and Differential (CVT) occurs constantly.

[0029] Thus, we have the first gear being the planetary reduction and the other gear ratios will be the sum of the rotations generated by the sun gear (210), planetary gear (220) and ring gear (240), and by the turbine (410) of the torque converter (400) turning the outer casing (200) and the differential support (280), turning the output shaft (300).

[0030] Power passes through the planetary gears (220) and the differential (270), and the modified torque converter (400), with the pump (430) and turbine (410) at the output, actually functions as a "torque transformer." The power is already at the output, but whether torque goes to the output shaft (300) or the pump (430) is determined by the nature of the motion, as energy always follows the easiest path. The vehicle's gear ratio is determined by the amount of torque going to the wheels or the turbine (410). If more torque is required for the wheels, the vehicle will be in power gears; if more torque is required for the turbine (410), the vehicle will be in speed gears. And the amount of torque going to the wheels or the turbine is controlled by the nature of the motion, meaning that power flows in whichever way is easiest.Power is a combination of rotation (speed) and torque, and power goes to the wheels where this combination is most suitable (where it flows most easily) for that moment.

[0031] Thus, in first gear all the torque goes to the output shaft (300), because the pump (430) is rotating slowly, but when part of the torque starts to go to the turbine (410) with the speed of the pump (430) increasing, the outer casing (200) will start to rotate, with the same rotation of the turbine (410), increasing the rotation of the output shaft (300) and, at this moment, the vehicle will no longer be in first gear. When the pump (430) and turbine (410) are rotating at the same speed (approximately) the vehicle will be in a 1: 1 ratio. Thus, the present invention uses the relative movement between the ring gear (240) and the outer casing (200), since the ring gear (240) is inside the outer casing (200), when the outer casing (200) starts to rotate, the ring gear (240) also rotates, and when both are at the same rotation, we are in a 1: 1 gear ratio.

[0032] The fact that the planetary support (230) is fixed to the external housing (200) and the differential (270) is at the output of the ring gear (240) is of primary importance so that the planetary reduction system (220) described here does not need any lock to operate.

[0033] With the present configuration, where the pump (430) of the modified torque converter (400) is connected to the output shaft (300), with the turbine (410) connected to the outer housing (200), and consequently, to the output shaft (300) as well, a torque balance is obtained between the output shaft (300) and the turbine (410) of the modified torque converter (400), which makes this transmission work as a CVT. This torque / speed balance between the output shaft (300) and the turbine (410) is obtained according to the instantaneous load at the output (inertia) and the power generated by the engine, and at all times the system is naturally fed back by inertia.

[0034] The easiest path for power to travel is the path of least resistance, and this difficulty is proportional to the output load. The instantaneous output load is felt at all times through the natural difficulty of the hydraulic fluid in keeping up with the gears (pump-turbine rotational ratios). Therefore, there are infinite changes in torque and rotational speed percentages that will either pass directly to the wheels or pass through the torque converter (400) and wheels. Therefore, this system is an inertial system, where gear changes depend on engine inertia and power.

[0035] Although a specific embodiment of the present invention has been presented, all those reasonably versed in the art will understand the possibility of modifications without departing from the spirit and scope of this invention, which is based on the planetary reduction that works without any lock and on the feedback by inertia. Therefore, the embodiment described above should be illustrative, not restrictive.

[0036] Likewise, the following example is merely illustrative of the embodiment of the invention, based on tests performed. This example, therefore, should not be used to delimit the inventor's rights, which should be governed by the content of the claims of the present invention. EXAMPLE

[0037] The rotation and torque ratios of the Continuously Variable Inertial and Differential Transmission (T), which is the object of the present invention, can be exemplified by the mathematical formulas described below, in which the following conventions were used for the indexes or subscripts that identify the elements of the device: ES = Sun Gear; EP = Planetary Gears; EA = Ring Gear; CE = External Housing; SP = Planetary Gear Support; XS = Output Shaft; and TB = Turbine.

[0038] Equations (1) and (2) are for common planetary gears and equation (3) is for an automotive differential: Rotation ES x Radius ES = Rotation SP x Radius SP — Rotation EP x Radius EP (1 ) Rotation EA x Radius EA = Rotation SP x Radius SP + Rotation EP x Radius EP (2) Rotation EA + Rotation xs = 2 x Rotation CE (3)

[0039] Deducing from the operation of the transmission we have the link: Rotation SP = Rotation CE = Rotation TB

[0040] Making the necessary substitutions, we arrive at the equation that governs the rotations of the Continuously Variable Inertial and Differential Transmission (T), which is the object of the present invention: (2 x Rotation CE x (RadiusEA - Ray SP + Rotation ES x Radius ES Rotation xs = Ray EA

[0041] Using fictitious values, such as: RaiOEs = 10, Radius p = 15, Radiusp = 25 and, Radiuse i = 40, with a fixed rotation of 2,000 rpm at the input. We will have: (2 x Rotation CE x (40 — 25 ) + Rotation ES x 10) Rotation xs = 40 (30 x Rotation CE + 10 x Rotation ES Rotation xs = 40

[0042] We then have the rotation of the output shaft (300) as a function of the rotation of the ring gear (240).

[0043] The graph of this equation, shown in Figure 8, demonstrates the behavior of the output shaft rotation (300) of the Inertial and Differential Continuously Variable Transmission (T), using an input rotation maintained constantly at 200 RPM on a straight line path without slopes or inclines.

[0044] The output torque can be easily found, since Power = Rotation x Torque. If we know the input power and the output rotation, we will know the output torque, discounting the natural losses of power transmission systems. But since in Transmission (T), the pump (430) and the turbine (410) are at the output, and the turbine (410) multiplies the torque of the pump (430). In situations where the turbine (410) is rotating much slower than the pump (430) (stall), we will still have the torque that is in the pump (430) multiplied at the output, in power gear situations. Common torque converters multiply the pump torque by approximately 2.5 times at the turbine, in turbine stall situations, due to the use of the stator. As the stator (420) is fixed to the vehicle's casing, it exerts a reaction force external to the system, diverting the flow of hydraulic fluid in the direction of rotation of the pump (430) and multiplying its torque on the turbine (410).So we can notice that the efficiency. will also depend on the torque multiplication factor of the modified torque converter (400) used in the Inertial Continuously Variable Transmission and Differential (T).

[0045] From the above, it is sufficiently clear that the Continuously Variable Inertial and Differential Transmission (T), now described, has a reduced number of simple mechanical components, which significantly reduces its manufacturing cost when compared to current CVT type automatic transmissions, which, in addition, has greater efficiency than current systems, where all losses are due to friction between the gears, since slippage between the pump (430) and the turbine (410) of the modified torque converter (400) does not cause great losses, because if the power is not transmitted to the turbine (410) of the modified torque converter (400), it will be transmitted to the wheels and can be applied without restriction in vehicles with combustion or electric engines, such as cars, motorcycles, scooters, bicycles, buses, trucks, and wherever else there is a need for torque transmission.Sliding losses between the pump and turbine will be due to heating of the fluid, which can be resolved by using an oil cooler, whose operation is well known in the state of the art.

Claims

CLAIMS 1. INERTIAL AND DIFFERENTIAL CONTINUOUSLY VARIABLE TRANSMISSION, which operates as a CVT type automatic transmission, characterized by comprising: - an input shaft (100), which receives power from the engine and the vehicle's common torque converter; - an external housing (200), with a substantially cylindrical shape, formed by a front area (200a), which is pierced by the input shaft (100), a side area (200b) and a rear area (200c), which in turn comprises the following components, immersed in lubricating oil: - a sun gear (210), directly connected to the input shaft (100); - three planetary gears (220), connected to the sun gear (210) and receiving power from it; - a support (230), fixed to the front area (200a) of the external housing (200), which serves as support for the three planetary gears (220); - a ring gear (240), smooth on its outer face and toothed on its inner face, which accommodates the three planetary gears (220) and the sun gear (210) inside; - a cover (250), which serves as a cover for the ring gear (240) and has movement in solidarity with it; - an output gear of the ring gear (260), which is fixed to the cover (250) of the ring gear (240) and has movement in solidarity with it; - a differential (270), in which one of its 4 gears is the output gear of the ring gear (260); - a differential support (280), which is fixed to the rear area (200c) of the external housing (200), and has movement independent of the ring gear (240); - an output shaft (300), which is fixed to one of the 4 differential gears (270), exiting through the rear area (200c) of the external casing (200) and presenting independent movement from it; - a modified torque converter (400) which in turn comprises the following components: - a housing (405), which is fixed to the rear area (200c) of the outer housing (200); - a turbine (410), which is fixed to the casing (405) and, consequently, the rear area (200c) of the external casing (200), presenting movement in solidarity with such components; - a pump (430), which is attached to the output shaft (300); - a stator (420), located between the turbine (410) and the pump (430), responsible for redirecting the hydraulic fluid that leaves the turbine (410) in the direction of rotation of the pump (430), being fixed to the vehicle casing; and - optionally, a lock-up (440), which performs the physical coupling between the casing (405), the turbine (410) and the pump (430) when they are rotating at cruising speed, allowing them to rotate together without slipping between them.

2. INERTIAL AND DIFFERENTIAL CONTINUOUSLY VARIABLE TRANSMISSION, according to claim 1, characterized in that the modified torque converter (400) is crossed throughout its entire length by the output shaft (300), which rotates freely inside it, being fixed only to the pump (430), which is positioned in the center of the device, and the turbine (410) is peripherally coupled to the casing (405), presenting movement in solidarity with it.

3. CONTINUOUSLY VARIABLE INERTIAL AND DIFFERENTIAL TRANSMISSION, according to claim 1, characterized in that the torque / speed balance between the output shaft (300) and the turbine (410) is carried out in accordance with the instantaneous load at the output (inertia) and the power generated by the engine, and the transmission system (T) is fed back by the instantaneous inertia of the vehicle in the following sequence: - the power from the engine accesses the transmission (T) via the input shaft (100); - the sun gear (210), which is directly connected to the input shaft (100), transfers the received power to the planetary gears (220); - the planetary gears (220) pass the power to the ring gear (240); - the ring gear (240), in turn, rotates in the opposite direction to the input shaft (100), and passes the power to the ring gear output gear (260); - the ring gear output gear (260) rotates the differential gears (270); - the differential (270) reverses the received rotation and transfers the power to the output shaft (300); - the output shaft (300) rotates the vehicle wheels and the pump (430) of the modified torque converter (400) at the same time, since the pump (430) is attached to the output shaft (300); - the pump (430) of the modified torque converter (400) drives the turbine (410) of the modified torque converter (400), which rotates the outer housing (200), which rotates the differential carrier (280), causing the differential (270) to rotate; and - the differential (270) divides the power between the output gear of the ring gear (260) and the output shaft (300), decreasing the rotation of the ring gear (240) in the opposite direction to the input shaft (100), thus increasing the rotation of the output shaft (300).

4. CONTINUOUSLY VARIABLE INERTIAL AND DIFFERENTIAL TRANSMISSION, according to claim 1, characterized in that it dispenses with the use of a lock for the operation of the planetary gear system (220), since the planetary support (230) is fixed to the outer housing (200) and the differential (270) is fixed to the output of the ring gear (240).

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