Internal lubricated transmission mechanism and associated electric propulsion assembly

Abstract

The invention relates to an internally lubricated transmission mechanism (M) comprising: a housing (40a, 40b) comprising a base (42) and a peripheral rim (43) defining an internal volume adapted to contain a lubricating fluid; at least one transmission shaft (10, 20, 30) comprising a toothed pinion, the at least one transmission shaft being rotatable about an axis of rotation (X1, X2, X3) relative to the housing; a guide bearing (100a, 200a, 300a) supporting the transmission shaft relative to the housing, the guide bearing comprising rolling elements, wherein the guide bearing is inserted into a cylindrical cavity (41) formed in the base of the housing; and a reservoir (90a, 90b) for retaining the lubricating fluid arranged within the housing, wherein the reservoir forms a first space (E1) encircling the transmission shaft.

Description

Technical Field

[0001] This invention relates to internal lubrication of transmission mechanisms, particularly reduction gear mechanisms, such as through splash lubrication. More specifically, this invention relates to the temperature rise of the lubricating fluid within the reduction gear mechanism between the start-up of the motorized vehicle and the moment it reaches a stable temperature, thereby reducing the time required to reach this stable temperature. The motorized vehicle can be an electric vehicle, a combustion engine vehicle, or a hybrid vehicle. Background Technology

[0002] To lubricate the components of a transmission mechanism, particularly the rotary guide bearings and gear sets of such a mechanism, it is known to place the rotating moving parts of the mechanism within an oil-containing housing, but without completely immersing the moving parts (e.g., the drive shaft supporting the pinion) in the oil. Thus, it is the movement of the transmission mechanism that, through splash lubrication, agitates the oil and sprays it throughout the entire internal volume of the housing, ensuring the desired lubrication of the entire mechanism (including the unimmersed parts).

[0003] When an electric or hybrid vehicle is started, the transmission mechanism, all its components, and the lubricating fluid housed within it are at ambient temperature. The guide bearings (e.g., ball bearings) supporting the rotating parts are lubricated, and lubricating fluid typically flows through these bearings. As they rotate, the guide bearings heat up, and the released heat is carried away by the lubricating fluid, which also warms up. However, after exiting the guide bearings, the fluid splashes throughout the housing, particularly onto the still-at-ambient-temperature inner walls. This contact with the housing delays the temperature rise of the lubricating fluid. Therefore, the thermal inertia of the inner walls of the housing constituting the reduction gear mechanism slows down the temperature rise of the lubricating fluid (e.g., lubricating oil).

[0004] For example, as illustrated in document JP 2011214658 A2, reduction gear mechanisms have very high thermal inertia, meaning that it can take tens of minutes for the lubricating oil temperature to stabilize. This means that when used in electric or hybrid vehicles with short operating cycles, the oil temperature may never stabilize and may remain below optimal operating conditions. During this transient phase, the proper internal relative positioning of the guide bearings cannot be guaranteed due to the unstable temperature rise of the various internal components of the transmission mechanism. This transient temperature rise phase needs to be as short as possible to allow the guide bearings to quickly achieve correct axial relative positioning and thus improve the reliability of these bearings. Summary of the Invention

[0005] This invention seeks to overcome the shortcomings of the prior art and proposes a transmission mechanism with reduced internal thermal inertia.

[0006] Therefore, according to a first aspect of the present invention, a transmission mechanism with internal lubrication is provided, the transmission mechanism comprising: The housing includes a base and a circumferential edge, the base and the circumferential edge defining an internal volume capable of receiving lubricating fluid; At least one drive shaft, the at least one drive shaft including a toothed pinion, the drive shaft being rotatable relative to the housing about its axis of rotation; and A lubricating fluid storage tank is disposed within a housing, the tank forming a first space surrounding a drive shaft, and the lubricating fluid storage tank includes closable baffles that are capable of retaining lubricating fluid in the tank when the closable baffles are in a closed position and of discharging lubricating fluid from the tank when the closable baffles are in an open position, and the thermal conductivity of the lubricating fluid storage tank is lower than that of the housing.

[0007] The thermal conductivity of the lubricating fluid reservoir is at most half that of the outer shell, for example, one-third that of the outer shell.

[0008] The unit for measuring thermal conductivity is watts per meter Kelvin (W / mK). The higher the thermal conductivity, the more thermally conductive the material; the lower the thermal conductivity, the more thermally insulating the material.

[0009] The lubricating fluid reservoir allows for temporary insulation of the transmission mechanism's housing from the lubricating fluid for a sufficient duration to allow the fluid to reach its optimal operating temperature. Therefore, this solution aims to reduce the transmission mechanism's thermal inertia without increasing its overall size.

[0010] According to one aspect of the invention, the lubricating fluid reservoir has a concave shape nested within the inner volume of the outer shell.

[0011] According to one embodiment of the invention, a lubricating fluid reservoir forms a first space that surrounds the drive shaft 360° around the axis of rotation of the drive shaft.

[0012] According to one embodiment of the invention, the volume contained in the first space, measured in cubic meters, can be greater than or equal to 60% of the internal volume of the outer casing, for example, greater than or equal to 80%. This limits the amount of lubricating fluid in contact with the outer casing, especially during the startup of electric or hybrid vehicles. To achieve this ratio, the shape of the lubricating fluid reservoir is conformed as closely as possible to the shape of the internal volume of the outer casing, while leaving a substantially constant dimensional gap between the reservoir and the outer casing.

[0013] According to one embodiment of the invention, the volume contained in the first space, measured in cubic meters, is less than 95% of the internal volume of the outer shell.

[0014] According to one embodiment of the invention, the lubricating fluid storage tank may have a wall defining the first space, and a second space is formed between the outer surface of the tank wall and the inner surface of the outer shell formed by the base and the circumferential edge, wherein the second space is capable of accommodating a portion of the lubricating fluid when the closable baffle is in the open position.

[0015] According to one embodiment of the invention, the transmission mechanism may include at least a guide bearing that supports the transmission shaft relative to the housing. The guide bearing includes rolling elements and is inserted into a cylindrical cavity formed in the base of the housing. The lubricating fluid reservoir includes at least one orifice that communicates directly or indirectly with the cylindrical cavity, and the orifice is capable of conveying fluid independently of the opening or closing of a closable baffle. In this way, the lubricating fluid passes through one or more guide bearings that generate heat due to rotation. Because the guide bearings generate heat, the released heat energy is carried away by the lubricating fluid, which then heats up.

[0016] According to one embodiment of the invention, the transmission mechanism may include a receiving tray for receiving and dispensing lubricating fluid, the receiving tray being housed in a first space, the receiving tray including at least a bottom, an outer periphery, and a fluid supply pipe extending from the bottom or the outer periphery through an orifice of the tank.

[0017] According to one embodiment of the invention, when the transmission mechanism is in the reference operating position, a receiving tray for receiving and distributing lubricating fluid can be arranged above the transmission shaft, between the axis of rotation of the transmission shaft and the wall of the container. In this way, the receiving tray functions as a receiving container and occupies a central position within the first space, thereby allowing the receiving tray to receive all splashed lubricant from the pinion of the transmission shaft. The lubricant can fall directly or indirectly into the receiving tray.

[0018] According to one embodiment of the invention, the transmission mechanism may include at least a guide bearing that supports the drive shaft relative to the housing. The guide bearing includes rolling elements and is inserted into a cylindrical cavity formed in the base of the housing. The housing includes at least one fluid delivery conduit that communicates a first space with the bottom of the cylindrical cavity. The fluid delivery conduit is capable of delivering fluid independently of the opening or closing of a closable baffle. In this way, lubricating fluid passes through one or more guide bearings that generate heat due to rotation. Because the guide bearings generate heat, the released heat energy is carried away by the lubricating fluid, which then heats up.

[0019] According to one embodiment of the invention, the lubricating fluid reservoir may have at least one through-hole through which at least one drive shaft passes. The through-hole may include a cylindrical surface portion that serves as a surface for centering the lubricating fluid reservoir on the housing.

[0020] According to one embodiment of the present invention, the lubricating fluid storage tank may have two through holes through which a drive shaft passes, with both ends of the drive shaft passing through the tank.

[0021] According to one embodiment of the present invention, the lubricating fluid reservoir may include two half-tanks forming a first space, the two half-tanks being assembled by fitting one into the other.

[0022] According to one embodiment of the invention, each half-can can be nested within the internal volume of the outer shell.

[0023] According to one embodiment of the invention, the outer casing may consist of a main outer casing and a closing outer casing, the closing outer casing being supported on the main outer casing at the parting line to provide a sealed enclosure of the internal volume of the outer casing. For example, two half-cans may be fitted one into the other in a plane parallel to the parting line of the outer casing. This makes the transmission mechanism easier to assemble. In this way, the half-cans can be housed within the internal volume of the main outer casing, and the shape of the half-cans can be nested within the internal volume of the main outer casing.

[0024] According to one aspect of the invention, two half-cans are assembled in one inside the other in a plane parallel to the parting line of the outer shell.

[0025] According to one embodiment of the present invention, the shut-off baffle can be operated according to the temperature of the lubricating fluid.

[0026] According to one embodiment of the invention, the reversible baffle can be operated based on a timeout associated with the start of rotation of the drive shaft.

[0027] According to one embodiment of the invention, at least one of the closable baffles may include a directional flap capable of deflecting lubricating fluid when the flap is in the open position, so as to redirect a portion of the lubricating fluid from the first space to the second space. Conversely, at least one of the closable baffles may include a directional flap capable of deflecting lubricating fluid when the flap is in the open position, so as to redirect a portion of the lubricating fluid from the second space to the first space.

[0028] According to one embodiment of the present invention, the closable baffle may include a fixed area and a hinge positioned between the directional flap and the fixed area.

[0029] According to one embodiment of the present invention, when the closable baffle is in the open position, the free end of the directional flap can press against the outer shell.

[0030] According to one embodiment of the present invention, the directional flap can be integrally produced with the tank wall.

[0031] According to one embodiment of the present invention, the closable baffle can be fixed to the wall of the tank by riveting, thermal bonding or adhesive bonding, and the hinge is positioned between the directional flap and the fixing area that supports the rivet or fusion bonding block or adhesive bonding block respectively.

[0032] According to one embodiment of the invention, the hinge may include a metal rod that acts as a hinge pin between the directional flap and the wall or fixed area of ​​the can.

[0033] According to one embodiment of the invention, the closable baffle may include a dual-material strip device manufactured in the form of two stacked elastic strips made of materials that expand unequally, the two elastic strips forming a fixing zone, a hinge, and an directional flap. Under the influence of temperature changes, the dual-material strip device bends, thereby opening or closing the directional flap. One of the elastic strips may be formed from the wall of a lubricating fluid reservoir.

[0034] For example, a closable baffle may include a dual-material strip device manufactured as an elastic strip attached to the wall of the tank, the elastic strip being made of a material that expands unequally relative to the material of the tank. Advantageously, the elastic strip may be stacked with a fixing zone, hinge, and directional flap.

[0035] According to one embodiment of the present invention, the shut-off baffle may be a valve with linear opening and closing movement.

[0036] According to one embodiment of the present invention, the shut-off baffle can be an electronically controlled valve.

[0037] According to one embodiment of the invention, the transmission mechanism may include an additional heat insulation device fixed to the transmission shaft in a rotational sense and at least partially covering the toothless portion of the transmission shaft axially and / or radially, the thermal conductivity of the additional heat insulation device being at most half that of the thermal conductivity of the transmission shaft, for example, one-third that of the thermal conductivity of the transmission shaft.

[0038] According to one embodiment of the invention, the additional heat insulation device may be a surface coating applied to the rough machined surface of the drive shaft.

[0039] According to one embodiment of the invention, the additional heat insulation device may be a plate in the form of a partial sheath, thereby extending axially along the axis of rotation and surrounding the cylindrical portion of the drive shaft.

[0040] According to one embodiment of the invention, the drive shaft may include rough machined surfaces as well as machined surfaces in contact with the guide bearing and / or splined surfaces in contact with the pinion, these rough machined surfaces being partially covered by additional thermal insulation. This solution aims to reduce the thermal inertia of the drive shaft without increasing the overall size of the transmission mechanism.

[0041] According to one embodiment of the invention, the housing may contain a lubricating fluid, such as oil, which reaches a static oil level plane when the transmission mechanism is in a reference operating position.

[0042] According to one embodiment of the invention, the transmission mechanism may include the following items housed in a housing: a first transmission shaft, which is guided by a first guide bearing to rotate about a first rotation axis and is fixed in a rotational sense to at least one drive pinion; a second transmission shaft, which is guided by a second guide bearing to rotate about a second rotation axis and is fixed in a rotational sense to at least one intermediate pinion; and a third transmission shaft, which is guided by a third guide bearing to rotate about a third rotation axis and is fixed in a rotational sense to at least one driven pinion, wherein the first transmission shaft, the second transmission shaft, and the third transmission shaft are housed within a first space formed by the can.

[0043] According to one embodiment of the present invention, the lubricating fluid reservoir may allow at least two drive shafts selected from a first drive shaft, a second drive shaft, and a third drive shaft to pass through it.

[0044] For example, the first drive shaft, the second drive shaft, and the third drive shaft are parallel to each other.

[0045] According to one embodiment of the invention, the third drive shaft may be a differential housing obtained by casting, the differential housing including machined surfaces that contact a third guide bearing, a planetary gear arranged in the differential housing, or a ring gear acting as a driven pinion, and additional heat insulation axially and / or radially covering all or part of the rough machined surfaces.

[0046] According to one embodiment of the present invention, the transmission mechanism may have one or more gear sets that establish a fixed transmission ratio between the driving pinion and the driven pinion, the transmission ratio being greater than one.

[0047] According to another aspect of the present invention, the present invention relates to an electric propulsion unit comprising an electric motor and a transmission mechanism, the transmission mechanism comprising all or some of the above-described features, wherein a first transmission shaft constitutes the output shaft of the electric motor or rotates integrally with the drive shaft of the electric motor.

[0048] According to one embodiment of the present invention, the stator of the electric motor can be fixed to the housing.

[0049] According to one embodiment of the present invention, the outer casing may be composed of a main casing supporting the motor and a closed casing supported on the main casing, the main casing supporting the first half-can and the closed casing supporting the second half-can.

[0050] Therefore, this solution aims to reduce the internal thermal inertia of the transmission mechanism without increasing the overall volume of the electric propulsion unit.

[0051] The present invention is particularly applicable to reduction gear transmission mechanisms, and particularly applicable to reducers with a fixed transmission ratio or two reduction ratios, parallel shaft reducers, or coaxial reducers including planetary gear sets, wherein the rotation axis of the motor is concentric with the output shaft of the planetary gear set. Attached Figure Description

[0052] Further features and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings.

[0053] [ Figure 1 ] Figure 1 It is a cross section passing through the transmission mechanism according to the first embodiment of the present invention.

[0054] [ Figure 2 ] Figure 2 yes Figure 1 Front view of the interior of the transmission mechanism.

[0055] [ Figure 3 ] Figure 3 yes Figure 1 Detailed view of the transmission mechanism.

[0056] [ Figure 4 ] Figure 4 This is a view of the transmission mechanism along a substantially vertical cross-sectional plane, with the transmission mechanism in a reference operating position.

[0057] [ Figure 5 ] Figure 5 This is an isometric view of a half-can according to a first embodiment of the present invention.

[0058] [ Figure 6 ] Figure 6 This is a detailed view of the closable baffle of the transmission mechanism according to a first embodiment of the present invention.

[0059] [ Figure 7 ] Figure 7 This is a detailed view of the closable baffle of the transmission mechanism according to a second embodiment of the present invention.

[0060] [ Figure 8 ] Figure 8 This is a detailed view of the closable baffle of the transmission mechanism according to a third embodiment of the present invention.

[0061] [ Figure 9 ] Figure 9 This is a cross-sectional view of a transmission mechanism according to a fourth embodiment of the present invention, with the transmission mechanism in a reference operating position.

[0062] [ Figure 10 ] Figure 10 This is a partial view of the transmission mechanism according to the fifth embodiment of the present invention.

[0063] For clarity, the same reference numerals are used throughout the accompanying drawings to identify the same or similar elements. Detailed Implementation

[0064] Figures 1 to 6 An electric propulsion unit 1 according to a first embodiment of the present invention is shown. The electric propulsion unit includes a motor 60 and a transmission mechanism M. In this example, the transmission mechanism M is a reduction mechanism that transmits torque from the motor 60 to the wheels of an electric vehicle or a hybrid vehicle.

[0065] Motor 60 may be, for example, an induction motor, which includes a rotor 62 and a stator 61, powered by a battery via a current converter (these are in... Figure 1 (Not shown) It is powered by three-phase AC. The motor can be of another type, such as an axial flux motor.

[0066] The motor 60 is held in place on housings 40a and 40b. The housings typically consist of a main housing 40a supporting the motor 60 and a closed housing 40b supported along a parting line 48 on the main housing 40a, to seal the cavity defined by the main housing 40a and the closed housing 40b. The main housing 40a includes a base 42 and a circumferential edge 43, which define an internal volume capable of receiving lubricating fluid.

[0067] The motor 60 rotates the first drive shaft 10 that enters the main housing 40a. The first drive shaft 10 constitutes the input shaft of the transmission mechanism M, which also includes a second drive shaft 20 and a third drive shaft 30, the third drive shaft constituting the output shaft of the transmission mechanism M.

[0068] The second drive shaft 20, which constitutes the intermediate shaft of the transmission mechanism M, is parallel to the input shaft 10 and the output shaft 30 of the transmission mechanism M. At the output end of the reducer, the third drive shaft 30 is a differential, which is used to transmit and distribute the torque from the motor 60 to the two half-shafts 2, 3 of one axle of the motor vehicle (not shown).

[0069] like Figure 1 As shown, the input shaft 10 is aligned with the drive shaft 63 of the motor 60 relative to the housings 40a, 40b, and supports at least one toothed wheel (referred to herein as drive pinion 11) rotatably connected to the drive shaft. The input shaft 10 is guided by two rotary-guided bearings 100a, 100b to rotate about a first rotation axis X1 relative to the housings 40a, 40b.

[0070] The guide bearing 100a, which supports the first drive shaft 10 relative to the housing, specifically includes a rolling element 103, in this case, bearing balls. The guide bearing 100a is inserted into a cylindrical cavity 41 formed in the closed housing 40b.

[0071] To lubricate the various components of the transmission mechanism M, housings 40a and 40b contain a lubricating fluid, such as oil. The guide bearing and the pinion of the drive shaft are partially immersed in the oil. Thus, it is the movement of the transmission mechanism that, through splash lubrication, agitates the oil and sprays it throughout the entire internal volume of the housing, ensuring the desired lubrication of the entire mechanism (including the unimmersed parts).

[0072] The output shaft 30 supports at least one driven pinion 31, which is fixed to it in a rotational sense. The output shaft 30 further includes a connection member, either fixed to or constituting a planetary gear carrier of the differential 32 in a rotational sense. The differential 32 can be an open differential or a limited-slip differential, depending on the desired characteristics. The output shaft 30 is guided by two rotary-guided bearings 300a, 300b for rotation about a third rotational axis X3 relative to housings 40a, 40b.

[0073] Similar to the input shaft 10 and the output shaft 30, the intermediate shaft 20 is guided by several rotary guide bearings 200a and 200b to rotate about the second rotation axis X2 and support two jointly rotating intermediate pinions 21 and 22. The first intermediate pinion 21 forms a first reduction gear set with the drive pinion 11 of the input shaft 10, and the second intermediate pinion 22 forms a second reduction gear set with the driven pinion 31 of the output shaft 30.

[0074] The first rotation axis X1, the second rotation axis X2, and the third rotation axis X3 are parallel to each other. The first rotation axis X1 and the third rotation axis X3 are positioned in the reference plane P of the transmission mechanism M. Figure 2 As shown, the second axis of rotation X2 is located outside the reference plane P.

[0075] The diameter and number of teeth of the driving pinion 11 are smaller than those of the intermediate pinion 21 forming the first reduction gear set on the intermediate shaft 20. Similarly, the diameter and number of teeth of the second intermediate pinion 22 forming the second reduction gear set on the intermediate shaft 20 are smaller than those of the driven pinion 31 on the output shaft 30. Therefore, the transmission mechanism M is a reduction gear device with no change in transmission ratio.

[0076] In the remainder of this specification, the reference operating position of the transmission mechanism M is defined as its three-dimensional orientation when mounted in a horizontal vehicle. In this reference operating position, the second rotation axis X2 is positioned above the reference plane P. Unless otherwise stated, the invention will be described in the reference operating position throughout the remainder of this specification.

[0077] The object of this invention is to reduce the internal thermal inertia of the transmission mechanism. To this end, the transmission mechanism M includes a lubricating fluid reservoir 90 disposed within housings 40a and 40b, which forms a first space E1 surrounding a first drive shaft 10, a second drive shaft 20, and a third drive shaft 30. The lubricating fluid reservoir 90 has the first, second, and third drive shafts passing through it. The ends of the drive shafts pass through the lubricating fluid reservoir 90.

[0078] The lubricating fluid storage tank 90 includes two half-tanks 90a and 90b forming a first space E1. To form a substantially enclosed first space E1, the first half-tank 90a and the second half-tank 90b are assembled by fitting one half into the other. The two half-tanks 90a and 90b are fitted one into the other in a plane parallel to the parting line 48 of the outer shell.

[0079] like Figure 2 and Figure 3 As shown, the first half-can 90a is housed within the internal volume of the main housing 40a, and the shape of the first half-can 90a is nested within the internal volume of the main housing. The first half-can 90a is directly fixed to the main housing 40a, for example, using fixing screws. Similarly, the second half-can 90b is nested within the closed housing 40b.

[0080] The lubricating fluid storage tank has a wall 93 defining a first space E1. A second space E2 is formed between the outer surface of the tank wall 93 and the inner surface of the outer shells 40a, 40b formed by the base 42 and the circumferential edge 43. The volume contained in the first space E1, measured in cubic meters, is greater than or equal to 70% of the internal volume of the outer shells 40a, 40b. The first half-tank 90a has a rib 98 that deflects the lubricating oil flow to the vicinity of the outer diameter of the driven pinion 31; the rib 98 is integrally formed with the wall 93.

[0081] like Figure 5 As shown, the lubricating fluid reservoir 90 includes closable baffles 110 that retain lubricating fluid in the reservoir when the baffles are in the closed position and discharge lubricating fluid from the reservoir when the baffles are in the open position. The lubricating fluid reservoir 90 includes two through-holes 97 through which a first drive shaft 10, a second drive shaft 20, and a third drive shaft 30 pass. Each through-hole 97 includes a cylindrical surface portion that serves as a surface for centering the lubricating fluid reservoir on the outer casing.

[0082] In this first embodiment of the invention, the outer shells 40a and 40b are made of aluminum, and the lubricating fluid reservoir 90 is made of plastic (e.g., polyamide).

[0083] The thermal conductivity of the lubricating fluid reservoir is lower than that of the outer shell. The thermal conductivity K2 of the material used to make the outer shell 40a, 40b, made of aluminum, is approximately 185 W / mK, while the thermal conductivity K1 of the lubricating fluid reservoir 90 is approximately 1 W / mK.

[0084] When an electric or hybrid vehicle is started, the transmission mechanism M, all its components, and the lubricating fluid contained in the housing are at ambient temperature. The lubricating fluid, in a stationary state, fills the lower part of the first space E1 and the lower part of the second space E2. The shut-off baffle 110 is in the closed position.

[0085] As the drive shaft begins to rotate, the oil contained in the first space E1 is agitated and begins to lubricate the guide bearings, through which the lubricating fluid typically flows. Due to their rotation, the guide bearings generate heat, and this released heat is carried away by the lubricating fluid, which also heats up. With the shut-off baffle 110 in the closed position, lubricating oil splashes throughout the lubricating fluid reservoir 90, particularly onto the wall 93, causing the wall's temperature to rise. During this phase, the lubricating oil remains contained within the first space E1.

[0086] Given that the thermal conductivity K1 of the lubricating fluid reservoir 90 is lower than that of the outer casing K2, the lubricating fluid contained in the first space E1 will not be cooled by the cold surfaces of the outer casings 40a and 40b. The gain is effective when the thermal conductivity K1 of the insulation device is at most half that of the thermal conductivity K2 of the drive shaft. The greater the difference in thermal conductivity, the faster the lubricating oil temperature rises.

[0087] When the temperature of the lubricating oil reaches a sufficiently high threshold (e.g., 70 degrees Celsius), the resealable baffle 110 changes position to the open position. In this case, the resealable baffle operates according to the temperature of the lubricating fluid. The lubricating oil can then enter the second space E2 and come into contact with the housings 40a and 40b.

[0088] like Figure 5As shown, one of the closable baffles 110 includes a directional flap 111 that, when in the open position, deflects the lubricating fluid to redirect a portion of it from the first space E1 to the second space E2. Similarly, the other closable baffle 110 includes a directional flap 111 that, when in the open position, deflects the lubricating fluid to redirect a portion of it from the second space E2 to the first space E1. The lubricating fluid follows a path from the first space E1 to the second space E2 and then back to the first space E1. The passage of oil within the first space E1 allows all components of the transmission mechanism M to be lubricated, and the passage of oil through the second space E2 allows the lubricating oil to be maintained at a stable temperature optimal for efficiency by dissipating heat through the aluminum of the housing.

[0089] According to an alternative form of the invention, the reversible baffle can be operated based on a timeout associated with the start of rotation of the drive shaft.

[0090] Since the thermal conductivity K1 of stainless steel is approximately 16 W / mK, stainless steel can be used to manufacture lubricating fluid storage tanks 90.

[0091] The path followed by the lubricating oil within the lubricating fluid reservoir 90 will now be described. Figure 3 and Figure 4 The transmission mechanism M is shown in a partial, simplified end view in the reference operating position, depicting the third transmission shaft 30, which is guided for rotation by means of a guide bearing 300b.

[0092] The guide bearing 300b includes a rotating inner ring, a non-rotating outer ring relative to the main housing 40a, and a rolling element 303 disposed between the two rings. The guide bearing 300b is inserted into a cylindrical cavity 41 formed in the base of the housing. The lubricating fluid reservoir 90 includes at least one orifice 95 indirectly communicating with the cylindrical cavity 41, capable of conveying fluid independently of the opening or closing of a shut-off baffle. In this way, the lubricating fluid passes through one or more guide bearings that generate heat due to rotation. Because the guide bearings generate heat, the released heat energy is carried away by the lubricating fluid, which then heats up.

[0093] During operation, housings 40a and 40b are filled with lubricating oil until they reach the set limit corresponding to the static oil level plane, which is horizontal when the transmission mechanism is in the reference operating position.

[0094] A portion of the reference plane P of the transmission mechanism M, defined by the first transmission shaft 10 and the third transmission shaft 30, is positioned above the static oil level plane.

[0095] A receiving tray 80 for receiving and distributing lubricating fluid is arranged between the first drive shaft 10 and the third drive shaft 30. The receiving tray 80 is housed in the first space E1. The receiving tray 80 contains some oil returned from the components of the transmission mechanism that are splashed and lubricated in oil.

[0096] The receiving pan 80 has at least one upper opening 82 located above the static oil level plane, a bottom 84, an outer perimeter 85, and a fluid supply pipe 81 extending from the bottom 84 or the outer perimeter 85. The fluid supply pipe 81 passes through an orifice 95 of the tank. Therefore, the lubricating oil flow can be specifically delivered to the upper region of the tank 90.

[0097] The receiving plate 80 enables the provision of a dynamic oil level that depends on the rotational speed of the input shaft 10, and more specifically, by accommodating some of the oil returning from the oil-splashed lubricated elements of the transmission mechanism, the oil level in the bottom of the tank 90 is reduced as the speed increases.

[0098] When stationary, that is, when stopped, the receiving plate 80 above the static oil level plane is empty, and the oil level corresponds to the static oil level plane. When the transmission mechanism M operates at a very low speed, the maximum oil level changes only slightly. This is because the driven pinion 31 rotates at a low speed; the driven pinion 31 is the largest toothed gear in the transmission mechanism M, and therefore the gear most likely to throw oil to various parts of the tank 90.

[0099] The faster the drive shaft rotates, the more oil is thrown to various parts of the tank via the rotation of the pinion gear. As the oil is thrown to different parts of the tank, it will eventually drip back down. - To mechanical parts, such as gears or bearings; and / or - To the bottom of the tank, where the oil settles; and / or -arrive Figure 4 The receiving plate 80 depicted is used for receiving and distributing lubricating fluid.

[0100] Therefore, the oil collected by the receiving plate 80 is partially guided into the groove 45 formed in the main housing 40a, so as to be delivered to the guide bearing 300b, as... Figure 4 As indicated by the arrow in the diagram. Recess 45 leads to the upper part of the cylindrical cavity 41 of the guide bearing 300b. Fluid supply pipe 81 passes through the orifice 95 of the tank 90 and leads to recess 45.

[0101] Therefore, the lubricating oil is directed toward the guide bearing 300b until it reaches the available space between the bottom 41a of the cylindrical cavity 41 and the rear surface of the guide bearing 300b. Under gravity, the lubricating fluid descends along the groove 45, then enters the cavity formed by the cylindrical cavity of the main housing 40a, and subsequently exits through the guide bearing 300b. The lubricating fluid then falls into the first space E1.

[0102] The structure of the closable baffle will now be described. For example... Figure 6 As shown, the closable baffle 110 includes a fixed area 112 and a hinge 113 positioned between the directional flap 111 and the fixed area. In this example, the directional flap 111 is integrally manufactured with the tank wall. Rotational movement of the directional flap 111 occurs around the hinge and tends to retract the directional flap into the first space E1.

[0103] The closable baffle 110 includes a dual-material strip assembly manufactured as an elastic strip 117 attached to the tank wall 93. The elastic strip 117 is made of a material that expands unequally relative to the tank material. The elastic strip is stacked with a fixing area 112, a hinge 113, and a directional flap 111. Under the influence of temperature changes, the dual-material strip assembly bends, thereby opening or closing the directional flap.

[0104] According to another alternative form of the invention (not depicted), the rotational movement of the directional flap 111 may tend to retract the directional flap into the second space E2. In this case, when the closable baffle is in the open position, the free end of the directional flap can press against the housing.

[0105] Now refer to Figure 7 A second embodiment of the invention is described, which differs from the first embodiment in that the hinge 113 includes a metal rod that acts as a hinge pin between the directional flap 111 and the tank wall 93 or the fixing area 112. The fixing area 112 supports the metal rod. Actuation of the directional flap can be assisted by an external actuator that orients the directional flap between an open position and a closed position.

[0106] Now refer to Figure 8 A third embodiment of the invention is described, which differs from the first embodiment in that the directional flap is fixed in a specific manner. In this third embodiment, the closable baffle 110 is fixed to the wall of the tank by rivets 114.

[0107] The closable baffle 110 includes a dual-material strip device manufactured in the form of two stacked elastic strips made of materials that expand unequally, forming a fixed area 112, a hinge 113, and an orientable flap 111. Under the influence of temperature changes, the dual-material strip device bends, thereby opening or closing the orientable flap.

[0108] According to an alternative form of the invention, the closable baffle can be thermally or adhesively bonded to the wall of the tank, the hinge being positioned between the directional flap and the fixed area supporting the fused or adhesively bonded block.

[0109] According to an alternative form of the invention, the shut-off baffle may be a valve with linear opening and closing movement, which is electromechanically controlled.

[0110] According to an alternative form of the invention, the shut-off baffle can be an electronically controlled valve.

[0111] Now refer to Figure 9 The fourth embodiment of the invention is described, which differs from the first embodiment in that the housings 40a and 40b include a fluid delivery conduit 47 that connects the first space E1 to the bottom 41a of the cylindrical cavity 41. This fluid delivery conduit 47 can deliver lubricating fluid to the guide bearing independently of the opening or closing of the shut-off baffle.

[0112] The oil collected by the receiving plate 80 is partially guided toward the fluid delivery conduit 47 formed in the main housing 40a, so as to be delivered to the guide bearing 300b, such as... Figure 9 As shown by the arrow in the diagram, the fluid delivery pipe 47 leads to the upper part of the cylindrical cavity 41 of the guide bearing 300b.

[0113] Therefore, the lubricating oil is directed toward the guide bearing 300b until it reaches the available space between the bottom 41a of the cylindrical cavity 41 and the rear surface of the guide bearing 300b. Under gravity, the lubricating fluid descends along the wall 93 and then enters the fluid delivery conduit 47 to reach the bottom 41a of the cylindrical cavity 41. After passing through the guide bearing 300b, the lubricating fluid falls into the first space E1.

[0114] Now refer to Figure 10 The fifth embodiment of the present invention is described below. The fifth embodiment differs from the first embodiment in that an additional heat insulation device 70 is used, the purpose of which is to further reduce the internal thermal inertia of the transmission mechanism.

[0115] For this purpose, the transmission mechanism M includes an additional heat insulation device 70, which at least partially covers the non-toothed portion of the third transmission shaft 30 axially.

[0116] The additional heat insulation device 70 is a surface coating applied to the rough machined surfaces of the third driveshaft 30. The third driveshaft 30 is a differential housing 32 obtained by casting, which includes machined surfaces 32a that contact the third guide bearings 300a, 300b, the planetary gears 35 arranged in the differential housing, or the ring gear that acts as the driven pinion 31. The additional heat insulation device covers all rough machined surfaces axially and radially.

[0117] The surface coating is applied directly to the differential housing 32 in its cast state and the body of the driven pinion 31 in its forged state. During machining operations, the surface coating is removed from all machined surfaces but remains on all rough machined surfaces. Machined surfaces 32a include, for example, the bearing housing of the guide bearing, splines, teeth, drilled holes, the support surface of the planetary gear 35, or the support surface of the driven pinion 31.

[0118] The surface coating is, for example, a water-based reactive prepolymer paint. This coating can be applied, for example, by electrostatic powder coating.

[0119] As an alternative, the surface coating can be a Teflon-based coating or a ceramic coating.

[0120] The advantage of the surface coating is that it allows for overcoming the complexity of the driveshaft's shape, and in this case, the complexity of the differential housing 32's shape. The thermal conductivity K3 of the surface coating is at most one-third that of the driveshaft's thermal conductivity K4. For example, the thermal conductivity of a driveshaft made of steel is 50 W / mK. In contrast, the thermal conductivity of the surface coating is less than 2 W / mK. Due to this difference in thermal conductivity, the lubricating fluid thrown into various parts of the first space E1, especially onto rotating parts, will not be cooled when a combustion engine vehicle, electric vehicle, or hybrid vehicle is started.

[0121] Of course, the examples shown in the figures and described above are given by way of non-limiting illustration only. It is expressly stated that the various embodiments shown can be combined to provide other embodiments.

[0122] According to an alternative form not shown, the transmission mechanism M is of the coaxial type, which includes a planetary gear set, wherein the rotation axis of the electric motor is concentric with the output shaft of the planetary gear set.

[0123] The aforementioned transmission mechanism M is a reduction mechanism with a constant transmission ratio and an intermediate shaft. However, the present invention can also be applied to mechanisms with several intermediate shafts or without intermediate shafts, mechanisms with several transmission ratios, and / or mechanisms where the ratio of input speed to output speed is less than 1.

[0124] The aforementioned transmission mechanism M is a reduction gear mechanism with internal lubrication via splash lubrication. However, the present invention can also be applied to reduction gear mechanisms with pressurized internal lubrication, wherein oil is delivered to the main lubrication points of the reducer via pipes or hoses. The oil then falls back to the bottom of the housing under gravity. In other examples, a mechanical or electric pump can be used to deliver pressurized fluid to the pipes or hoses.

Claims

1. A transmission mechanism (M) with internal lubrication, comprising: A housing (40a, 40b) comprising at least a base (42) and a circumferential edge (43), the base and the circumferential edge defining an internal volume capable of receiving lubricating fluid; At least one drive shaft (10, 20, 30), the at least one drive shaft including a toothed pinion (11, 21, 22, 31), the drive shaft being rotatable relative to the housing about a rotation axis (X1, X2, X3) of the drive shaft; as well as A lubricating fluid reservoir (90, 90a, 90b) is disposed within the housing, the reservoir forming a first space (E1) surrounding the drive shaft, and the lubricating fluid reservoir includes a closable baffle (110) capable of retaining the lubricating fluid in the reservoir when the closable baffle (110) is in a closed position and capable of discharging the lubricating fluid from the reservoir when the closable baffle (110) is in an open position, and the thermal conductivity (K1) of the lubricating fluid reservoir is lower than the thermal conductivity (K2) of the housing.

2. The transmission mechanism (M) as described in the preceding claim, wherein, The volume contained in the first space (E1), measured in cubic meters, is greater than or equal to 60% of the internal volume of the outer shell, for example, greater than or equal to 80%.

3. The transmission mechanism (M) as described in any one of the preceding claims, wherein, The lubricating fluid storage tank (90, 90a, 90b) has a wall (93) defining the first space (E1), and a second space (E2) is formed between the outer surface of the wall (93) of the tank and the inner surface of the outer shell (40a, 40b) formed by the base (42) and the circumferential edge (43), which is capable of accommodating a portion of the lubricating fluid when the closable baffle (110) is in the open position.

4. The transmission mechanism (M) as described in any one of the preceding claims, wherein, The lubricating fluid reservoirs (90a, 90b) have at least one through hole (97), through which the at least one drive shaft (10, 20, 30) passes.

5. The transmission mechanism (M) as described in any one of the preceding claims, wherein, The lubricating fluid storage tanks (90, 90a, 90b) have two half-tanks (90a, 90b) forming the first space (E1), which are assembled by fitting one into the other.

6. The transmission mechanism (M) as described in any one of the preceding claims, wherein, The shut-off baffle (110) operates according to the temperature of the lubricating fluid.

7. The transmission mechanism (M) as described in any one of the preceding claims, wherein, At least one of the closable baffles (110) includes a directional flap (111) that, when in the open position, deflects the lubricating fluid to redirect a portion of the lubricating fluid from the first space (E1) to the second space (E2).

8. The transmission mechanism (M) as described in any one of the preceding claims, wherein, At least one of the closable baffles (110) includes a directional flap (111) that, when in the open position, deflects the lubricating fluid to redirect a portion of the lubricating fluid from the second space (E2) to the first space (E1).

9. The transmission mechanism (M) as described in claim 7 or 8, wherein, The closable baffle (110) includes a fixed area (112) and a hinge (113) positioned between the directional flap (111) and the fixed area.

10. The transmission mechanism (M) as described in the preceding claim, wherein, The closable baffle (110) includes a dual-material strip device, which is produced in the form of two stacked elastic strips made of unequally expanded materials, the two elastic strips forming the fixed area (112), the hinge (113) and the directional flap (111).

11. The transmission mechanism (M) as claimed in any one of the preceding claims, comprising at least a guide bearing (100a, 200a, 300a) supporting the transmission shaft relative to the housing (40a, 40b), the guide bearing comprising rolling elements (103, 203, 303), the guide bearing being inserted into a cylindrical cavity (41) formed in the base (42) of the housing, the lubricating fluid reservoir (90, 90a, 90b) comprising at least one orifice (95) directly or indirectly communicating with the cylindrical cavity (41), the orifice (95) being capable of conveying fluid independently of the opening or closing of the closable baffle.

12. The transmission mechanism (M) of the preceding claim includes a receiving tray (80) for receiving and dispensing lubricating fluid, the receiving tray being housed in the first space (E1), the receiving tray including at least a bottom (84), an outer periphery (85), and a fluid supply pipe (81) extending from the bottom or the outer periphery, the fluid supply pipe (81) passing through an orifice (95) of the tank.

13. The transmission mechanism (M) as claimed in any one of claims 1 to 10, comprising at least a guide bearing (100a, 200a, 300a) supporting the transmission shaft relative to the housing (40a, 40b), the guide bearing comprising rolling elements (103, 203, 303), the guide bearing being inserted into a cylindrical cavity (41) formed in the base (42) of the housing, the housing comprising at least one fluid delivery conduit (47) communicating the first space (E1) with the bottom of the cylindrical cavity (41), the fluid delivery conduit (47) being capable of delivering fluid independently of the opening or closing of the closable baffle.

14. The transmission mechanism (M) as claimed in any one of the preceding claims, comprising an additional heat insulation device (70) fixed to the transmission shaft (100, 200, 300) in a rotational sense, and the additional heat insulation device at least partially axially and / or radially covering the toothless portion of the transmission shaft, the thermal conductivity (K3) of the additional heat insulation device (70) being at most half of the thermal conductivity (K4) of the transmission shaft, for example, one-third of the thermal conductivity of the transmission shaft.

15. The transmission mechanism (M) as claimed in any one of the preceding claims, further comprising the following items housed in the housing (40a, 40b): a first transmission shaft (10), which is guided by a first guide bearing (100a, 100b) to rotate about a first rotation axis (X1) and rotates integrally with at least one drive pinion (11); a second transmission shaft (20), which is guided by a second guide bearing (200a, 200b) to rotate about a second rotation axis (X2) and rotates integrally with at least one intermediate pinion (21, 22); and a third transmission shaft (30), which is guided by a third guide bearing (300a, 300b) to rotate about a third rotation axis (X3) and rotates integrally with at least one driven pinion (31), wherein the first transmission shaft (10), the second transmission shaft (20), and the third transmission shaft (30) are housed in the first space (E1) formed by the can.

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