Gear speed reducer, gear motor and vehicle provided with gear speed reducer

Abstract

The invention relates to a gear motor and a gear reduction device for directly driving the drive wheels of an electric traction vehicle, in which the traction motor is intended to have a gear reduction device comprising gears, which reduction device can be connected to the drive wheels, which gear reduction device comprises respective pinions configured with degrees of freedom of motion, the invention further discloses a vehicle comprising the gear speed reducer.

Description

Technical Field

[0001] The invention relates to a gear reduction device and a gear motor for directly driving the wheels of an electric traction vehicle, and to an electric traction vehicle provided with such a gear reduction device according to the features of the preamble of the main claim. Background Art

[0002] In the field of transmitting motion to the drive wheels of electric traction vehicles, in general and in particular for example industrial vehicles like tractors, forklifts, machines in motion, the use of gear motors is known, in which an electric motor is associated with a mechanical gear reduction that transmits the motion to the wheels.

[0003] The steering is managed by an electrical system that monitors the signals from speed sensors present on each of the two motors provided on a pair of opposing wheels of the vehicle and forms a transducer that measures the steering angle.

[0004] The current trend is towards the use of faster and more compact electric motors in order to reduce the outer dimensions of the gearmotor systems, and end users demand increasingly silent motors.

[0005] Application WO 2007022865 in the name of the same applicant describes a gear motor for direct driving of the wheels of an electric traction vehicle, wherein the traction motor is integrated with a reduction transmission connected to the drive wheel, and wherein the traction motor comprises a through drive shaft comprising a pinion on the wheel side, said pinion meshing internally in a corresponding gear chamber with a reduction transmission system integrated in the wheel for traction movement, and on the side opposite the wheel, said pinion is keyed to the brake system, the traction motor also being integrated in a corresponding opposite brake chamber and being equipped with the same components, forming a removable motor-brake assembly, and wherein the transmission reduction group is housed in a structural support housing connectable to the vehicle, and the motor group has its support housing, which is fixed to the structural support housing as a cover, covers the reduction system and allows free access after it has been opened.

[0006] Application WO 2013 / 102484 describes a gear motor for directly driving the wheels of an electric traction vehicle, wherein the traction motor is integrated with a gear reduction device, which is connectable to the drive wheels of the electric traction vehicle corresponding to the wheel hub, wherein the gear reduction device is accommodated in a structural support box, which is connectable to the vehicle through fixing holes, and the traction motor has a supporting housing fixed to the box as a cover, the box and the cover forming a single structural support housing of the gear motor, wherein the traction motor is a motor, whose transmission shaft is connected or integrated with the first pinion of the gear reduction device, and wherein a motor control inverter is accommodated corresponding to the closing cover of the motor.

[0007] Application US2939346A describes a two-stage gear reduction mechanism comprising a first stage and a second planetary stage placed adjacent to the first stage, the first stage comprising a pinion and a reduction gear, a pair of shafts, one of the shafts being integrated with the reduction gear of the first stage and the other shaft being integrated with the planet of the second stage, the shafts being connected at their ends away from the corresponding gear units by loosely matching splines, which allow the planetary gears to oscillate in a plane perpendicular to the axis of rotation.

[0008] Application US4090416 describes a gearbox used as a transmission connection between coaxial shafts of a driving shaft and a driven shaft, wherein the gear train is present in a housing of the gearbox, which is connected to these shafts by a flexible joint arranged inside the housing around the center of a bearing on which the housing is mounted.

[0009] Problems with existing technology

[0010] Prior art solutions are generally difficult to adapt to compact motors characterized by high rotational speeds.

[0011] Furthermore, the solutions of the prior art have large dimensions, also because of the use of motors having large dimensions, as a result of which they are subject to higher costs and also to higher weight and dimensions of the vehicle in which these devices are used.

[0012] In order to reduce the size of the gear motor as much as possible in general, efforts are usually made to reduce the motor, applying a reduction ratio so that the motor can reach a speed of, for example, 8000-12000 rpm. In this way, it is possible to reduce the size of the motor by 50% ca., relative to a conventional motor for this application, which runs at a speed of about 5000 rpm.

[0013] However, by increasing the motor speed, in addition to an increase in vibrations, higher noise also occurs, which may be generated in the gearmotor system as a whole.

[0014] The use of increasingly compact motors and motors with ever-higher speeds poses a greater challenge in achieving a transmission that is as silent as possible.

[0015] The solutions of the prior art are therefore both noisy and subject to vibrations, with the result that they are uncomfortable for the user operating the vehicle. Furthermore, the presence of vibrations may cause further problems, such as early wear of components of the gear-motor, loosening of the fixing system of the gear-motor of the vehicle, transmission of vibrations to the vehicle, subjecting the vehicle to undesirable stress conditions and mechanical stresses.

[0016] Furthermore, there are problems related to the fact that the gearmotor closed in its casing is sensitive to the mechanical deformations to which the same casing is subjected due to the loads of the wheel acting on the hub of the gearmotor under different operating conditions.

[0017] Purpose of the invention

[0018] The object of the invention is to provide a gear reduction device and a gear motor for direct transmission to the wheels of an electric traction vehicle, and an electric traction vehicle provided with such a gear reduction device, provided with an arrangement for limiting the transmission of vibrations and their influence on the internal components of the gear-motor.

[0019] Concept of the Invention

[0020] By means of the features of the main claim, the object is achieved in that a gear reduction device is provided with a pinion which is movably supported on an axis different from the axis of rotation of the pinion.

[0021] The dependent claims represent advantageous solutions.

[0022] Advantageous Effects of the Invention

[0023] The solution according to the invention, through a considerable creative contribution, constitutes an immediate and important technical advance with various advantages.

[0024] The gear reduction device according to the invention is quieter than prior art solutions using a gear reduction device coupled to a high-speed electric motor.

[0025] Advantageously, the gear reduction device structure according to the invention is less subject to mechanical stresses caused by forces introduced via the wheel hub. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] A solution, which is considered to be a non-limiting embodiment of the invention, is described below with reference to the accompanying drawings, in which:

[0027] Figure 1 A cross-sectional view of a prior art gear motor is shown.

[0028] Figure 2 A detailed cross-sectional view of a prior art gear motor is shown.

[0029] Figure 3 A detailed cross-sectional view of a prior art gear motor is shown.

[0030] Figure 4 An exploded view of a gear motor including a gear reduction device according to the present invention is shown.

[0031] Figure 5 Shows Figure 4 An exploded view of a portion of the motor of a gear motor.

[0032] Figure 6 Shows Figure 4 A view of a portion of the motor of a gear motor.

[0033] Figure 7 A cross-sectional view of a gear motor including a gear reduction device according to the present invention is shown.

[0034] Figure 8 A detailed cross-sectional view of a portion of a gear reduction device according to the present invention is shown.

[0035] Fig. 9 A detailed cross-sectional view of a portion of a gear reduction device according to the present invention is shown.

[0036] Fig.10 A perspective view showing a second pinion of the gear reduction device according to the present invention.

[0037] Fig.11 A cross-sectional view showing a second pinion of a gear reduction device according to the present invention.

[0038] Fig.12 A view showing a detail of a portion of the second pinion.

[0039] Fig.13 A detailed cross-sectional view of a gear reduction device according to the present invention is shown under stress conditions.

[0040] Fig.14 A noise diagram of a prior art solution is shown.

[0041] Fig.15 A noise diagram of the solution according to the invention is shown.

[0042] Fig.16 A vehicle in which a gear motor is integrated according to the invention is schematically shown. Summary of the invention

[0043] Refer to the attached figure ( Figure 1 , Figure 2 , Figure 3 ), solutions according to the prior art and solutions according to the present invention ( Figure 7 , Figure 8 , Fig. 9) With regard to the gear motor 5, the gear motor comprises a motor 6 mechanically connected to a corresponding gear reduction device 4, the gear motor being generally conceived in such a way that the gear reduction device 4 and the motor 6 are two different and separate entities, which are mechanically coupled to each other via a motor shaft 8 of the motor 6, also forming a coupling end 14 of the gear 2 of the reduction stage of the gear reduction device 4. The motor shaft 8 is rotatably supported inside the motor 6 in a restricted manner and protrudes from the motor 6 via a first end 27 ( Figure 1 , Figure 6 , Figure 7 ) in order to form a connection with the gear assembly 2 of the gear reduction device 4, the connection taking place between the motor shaft 8, which also represents the connection end 14 to which the gear 2 is connected, and the input end of the gear 2 for operating the gear reduction device 4, which is made by the first rim 17 of the first reduction stage of the gear 2, in such a way that the rotation transmitted to the motor shaft 8 by the associated motor 6 causes a corresponding rotation of the first rim 17, which in turn causes the other gears 2 of the gear reduction device 4 to rotate, thereby transmitting the movement to the hub 1, which is integrated with the drive wheel, in order to move the corresponding ( Fig.11 ) electric traction vehicle 31. The gear 2 comprises, in addition to the first wheel rim 17, a planetary stage pinion 15 which rotates at the same speed as the first wheel rim 17. With reference to the function of the gear motor 5, the drive wheel is mounted on a corresponding hub 1 which is integrated with a planetary gear carrier 11 of a second reduction stage of the gear reduction device 4, or in any case with a planetary gear carrier 11 of a second reduction stage of the gear reduction device, which second reduction stage is a planetary reduction stage. In the embodiment shown, the hub 1 is rotatably supported by a box 7 which represents the case of the gear reduction device 4 by means of corresponding first roller bearings 36. The planetary gear carrier 11 is fixed by means of a blocking ring nut 13 which is screwed on a corresponding threaded portion protruding from the hub 1 ( Figure 1 , Figure 4 , Figure 7 , Fig. 9 ) onto the hub 1. Inside and axially of the projection including the threaded portion, on the hub 1, a coupling seat 19 for the end of the pinion 15 is obtained. The planetary gear carrier 11 in turn receives the motion ( Figure 1 , Figure 4 , Figure 7 , Fig. 9 ), in the embodiment shown, the planetary gears are three planetary gears, each of which is inserted into corresponding three engagement seats on the planetary gear support 11 through corresponding second roller bearings 35. The second reduction stage gear ( Figure 1 , Figure 7) of the planetary gear 12 is located on the corresponding second rim 10 or rim of the planetary stage, which is fixed and mounted by a corresponding rim support plate 9. The rim support plate 9 is screwed on the housing 7 of the gear reduction device 4. The second rim 10 is fixed to the housing 7 by a corresponding fixing ring or rim support plate 9. The planetary gear 12 is received by the pinion assembly 15 and the first rim 17 ( Figure 1 , Figure 7 ) movement. The first toothed rim 17 meshes directly on the coupling end 14, which is obtained directly on the motor shaft 8 of the motor 6. All the gears of the gear reduction device 4 are combined in a first chamber 18 or chamber of the gear reduction device. The brake 3 or the braking system ( Figure 1 , Figure 4 , Figure 7 ) acts on the motor shaft 8 for braking. It will be apparent to a person skilled in the art that the brake 3 can be arranged to engage the motor shaft 8 on the second end 28, on the opposite side relative to the first end 27 of the motor shaft 8, coupled to the gear reduction device 4, as shown in the figures, but known and equivalent embodiments can be envisaged, wherein the brake 3 is arranged in such a way as to engage the motor shaft 8 on the same side of the motor shaft 8 to be coupled to the gear reduction device 4, i.e. at the first end 27.

[0044] With particular reference to the prior art solutions ( Figure 1 , Figure 2 , Figure 3 ), the pinion 15 is an integral part of the rim 17, so that the pinion 15 and the first rim 17 are a single body, wherein the pinion 15 is arranged axially and centrally in the body relative to the first rim 17 or the first reduction stage rim of the gear reduction device. The assembly of the pinion 15 and the first rim 17 is supported from the side opposite to the side from which the pinion 15 is obtained by means of the corresponding first ball bearing 21 of the pinion ( Figure 3 ), which first ball bearing is applied on the cover 16 of the gear reduction device 4. Thus, the single body consisting of the assembly of the pinion 15 and the first rim 17 is rotatably supported on a first side by the cover 16 via the first needle bearing 22 and on a second opposite side by the hub 1.

[0045] Refer to the attached figure ( Figure 4 , Figure 6 , Figure 7 ), the gear motor 5 for direct transmission to the wheels according to the invention makes it possible to obtain a single body constituted by the gear reduction device 4 and the motor 6, thus obtaining a compact and wear-resistant solution having all the advantages offered by a structure made in a single block, and moreover integrating systems and arrangements for reducing vibrations and stresses, as will be further described hereinafter.

[0046] Similar to the solution of the prior art, the motor 6 comprises ( Figure 5 , Figure 6 ) corresponding housing 37, and the gear motor 5 according to the present invention includes ( Figure 7 ) The structural housing 25 of the gear motor 5 is constituted by a first supporting housing constituted by the cover 16 and a second housing constituted by the box 7. The assembly of the box 7 and the cover 16 represents the entire cover or housing 25, containing both the motor 6 and the gear reduction 4, which become integral components of the transmission, together with the motor housing 37. This solution advantageously allows full access to the inside of the gear motor 5, since by removing the cover 16, the gear motor 5 is easily opened into two parts, the gear reduction 4 on one side, with its elements fully accessible, and the motor 6 on the other side.

[0047] In addition to the encoder 40 for detecting the actual rotation speed, the motor 6 advantageously comprises ( Figure 5 , Figure 6 ) A control connector 38 and a power terminal block 39 directly integrated into the corresponding housing 37.

[0048] Advantageously, in this way, all misalignment and insertion problems that may be experienced during the installation of an external motor can be avoided. The housing 25 comprises one or more chambers that can be used as oil reservoirs and / or as channels for oil recirculation if one wishes to use all the oil of the gear reduction unit for cooling purposes.

[0049] In the solution according to the invention, the motor shaft 8 directly comprises a coupling end 14 to the first reduction stage of the gear motor 5. In fact ( Figure 4 , Figure 7 ), the coupling end 14 of the motor shaft 8 is mechanically processed to obtain a coupling element 20 between the motor 8 and the gear 2 of the gear reduction device 4.

[0050] Furthermore, the motor shaft 8 also represents a connection element for applying a braking system. In fact, from the side opposite to the motor side, corresponding to the body of the motor itself, the brake (3) is obtained ( Figure 4 , Figure 7 ), which side of the motor corresponds to the side where the coupling element 20 of the coupling end 14 of the motor shaft 8 is present. Also in this case, it will be obvious to a person skilled in the art that known and equivalent embodiments can be provided in which the brake 3 is arranged in such a way that it engages the motor shaft 8 corresponding to the same side where the motor shaft 8 is coupled to the gear reduction device 4.

[0051] Motor axis 8 has a triple function:

[0052] - an input gear of the gear reduction device via the coupling end 14 of the motor shaft 8;

[0053] - actual motor shaft 8;

[0054] - Application connection of the brake system 3.

[0055] Thanks to this solution, it is possible to obtain a very compact and inexpensive transmission which reaches almost absolute limits of constructional precision: by obtaining the input gear of the gear reduction directly on the motor shaft 8, it is possible to increase the reduction ratio, thus increasing the speed of rotation of the motor 6, thanks to a particularly precise constructional shape. In fact, the solution according to the invention is preferably envisaged to provide for the use of high-speed motors which, during their operation, work at speeds of 8000-12000 revolutions per minute, for example. In order to reduce the noise to a level similar to or lower than that of the motors usually used in the prior art which work at a speed of 5000 revolutions per minute, it is necessary that the precision of the first reduction stage is the greatest and that the gears obtained directly on the motor shaft 8 be ground according to the highest precision standards.

[0056] In order to allow the use of high-speed motors 6 , it is necessary to develop technical solutions aimed at reducing the problem of the presence of buckling and / or deformations which, besides premature wear of the components, may lead to undesirable high-frequency vibrations.

[0057] Using a high speed motor, for example, a motor with a speed of 8000-12000 rpm allows for many advantages:

[0058] - The motor is particularly compact and therefore cheap and lightweight. For example, the solution according to the invention allows the use of a motor having a high rotation speed and being particularly compact, so that the use of this motor allows a 40% reduction in dimensions with respect to a solution comprising a standard motor, except for the connection flange of the frame towards the inside of the machine. Moreover, with respect to a solution comprising a standard motor, the use of this motor allows working at the maximum input speed of the double transmission, ie an increase of 100%, with all its benefits, as explained in this description;

[0059] - the maximum input torque is almost halved relative to prior art constructions, allowing the use of smaller gears for the gear reduction device 4; in particular, the coupling element 20 between the motor and the gear 2 of the gear reduction device can be easily produced directly on the motor shaft 8;

[0060] - the reduction ratio of the gear reduction device 4 increases in proportion to the speed;

[0061] - By applying the dynamic service brake 3 or the holding brake acting on the motor shaft 8, with the same braking effect, the brake 3 will have to generate a smaller braking torque.

[0062] The gear motor 5 may or may not involve the use of an oil-bath motor, in this way creating a system in which the oil of the gear reduction unit is recirculated through suitable pipes that do not contact the motor rotor, so as to carry out the usual form of cooling of the gear motor as a whole: in this way the use of sealing gaskets between the motor 6, the gear motor 5 and the brake 3 can be avoided, in favor of mechanical efficiency.

[0063] Advantageously, in addition to the aforementioned functions of the motor shaft 8 and the coupling element to the gear 2 of the gear reduction 4, the motor shaft 8 further performs the function of a brake shaft, since the motor shaft 8 projects outside the body of the motor itself, corresponding to the opposite side relative to the side where there is a junction between the motor 6 and the gear reduction 4, although an embodiment is possible in which the brake 3 is positioned on the side corresponding to the junction between the motor 6 and the gear reduction 4. The brake or brake system 3 can be made, for example, in the form of an electromagnetic type.

[0064] The gear motor 5 ( Figure 7 , Figure 8 , Fig. 9 ) integrates a number of different aspects that contribute to the realization of a gear motor 5 suitable for use with high-speed motors and allows:

[0065] - Use of planetary transmissions with helical teeth;

[0066] - Use of damping system for planetary rims;

[0067] - the use of a floating pinion which is free both relative to the hub and relative to the first transmission rim by coupling with a groove joint of the spherical type;

[0068] - the first transmission rim is fully supported by a double bearing, with the advantage that, since the pinion is floating, possible deformations of the box due to the load of the wheel do not cause a change in the contact between the pinion and the rim, thus improving quietness and reducing wear;

[0069] - Optimize the first drive in terms of helix angle to correct the grinding profile to optimize contact.

[0070] The term "floating" in relation to the pinion 15 means that the pinion 15 is disengaged from both the hub 1 and the planetary carrier 11 and is limitedly constrained to the first wheel rim 17 only by means of a groove joint 30 of the spherical type. Due to the fact that the pinion 15 is floating, possible deformations of the box 7 due to the load of the wheel do not cause undesirable loads to be applied between the pinion 15 and the first wheel rim 17, with the advantages of reducing noise as well as increasing reliability and reducing wear. In the prior art ( Figure 1 , Figure 3), the pinion 15 is constrained in a fixed position by bearings 21, 22 which only allow it to rotate about its own axis. In this way, the gears of the gear reduction unit are sensitive to the deformations of the box 7 caused by the loads of the wheel acting on the hub 1 under different operating conditions.

[0071] In the solution according to the invention ( Fig. 9 ), the pinion 15 is carried in a direct and limited manner without any bearing and is free to move axially along its own axis 33 within the limits imposed by the fixing ring 29. Furthermore, the toothed joint 30 between the pinion 15 and the first rim 17 is of the “spherical” type, i.e. it allows a limited oscillation of the axis 33 of the pinion 15 according to an angle A. For example, the maximum oscillation angle A of the pinion 15 may be in the range of + / -0.5° to + / -4°, preferably in the range of + / -1°a+ / -2°.

[0072] This ensures that deformation of the case 7 or vibration of the pinion 15 is not transmitted to the first rim 17 , in this way reducing the noise of the gear motor 5 .

[0073] Experimental results on the noise level generated by the gear motor ( Fig.14 , Fig.15 ) shows a clear improvement over the prior art solution. In fact, in the prior art solution ( Fig.14 ), relative to the solution according to the invention ( Fig.15 ) experimental test, the noise level is significantly higher.

[0074] The second wheel rim 10 of the planetary stage is fixed by the wheel rim support plate 9 ( Figure 7 , Figure 8 ) to the box 7, the rim support plate is connected to the second rim 10 by a wire 32 spring or elastic ring. In addition ( Figure 8 ), the second rim 10 is provided with two grooves 23, 24, in each of which a corresponding O-ring 26 is accommodated. The function of the O-ring 26 is to damp the vibrations transmitted from the second rim 10 to the box 7. Since the second rim 10 does not rotate, it is integral with the second housing or box 7, and the O-ring 26 pushes against the second rim 10 and the box 7, achieving a damping effect of the vibrations. Therefore, the second rim 10 and the box 7 are not in direct contact with each other, but the second rim 10 is supported by the box 7 through the interposition of the O-ring 26. For example, there is a minimum spacing of about 0.5 mm between the second rim 10 and the box 7, so as to ensure that there is no direct contact between these two elements.

[0075] In order to achieve said oscillating effect of the axis 33 of the pinion 15, the pinion 15 comprises a first portion 41 forming an engagement for coupling to the planetary gear 12 which receives the movement through the assembly of the pinion 15 and the first rim 17, and further comprises a second portion 42 forming an engagement for coupling to the first rim 17. Between the first portion 41 and the second portion 42, there is preferably a third portion 43 for connecting the configuration of the first portion 41 and the second portion 42. The first portion 41 preferably has a larger diameter than the second portion 42.

[0076] The second portion 42 forming the engaging portion for coupling with the first wheel rim 17 is made as a gear for coupling ( Fig.10 , Fig.11 , Fig.12 ) form, obtained on the surface of a cylindrical shape, wherein the teeth 47 of the gear bulge outwards, having an arched convex profile, i.e., the teeth 47 have a first height H1 corresponding to the central area of ​​the gear, and the teeth taper at the ends of the teeth, having a second height H2 corresponding to the end areas of the gear, wherein the second height H2 is smaller than the first height H1. Preferably ( Fig.12 ), according to a symmetrical configuration, taking into account the length L of the tooth 47, the tooth 47 has a height of a first height H1 corresponding to L / 2 and a height of a second height H2 corresponding to the end relative to the length L of the tooth 47. Thus, the height of the tooth 47 decreases in both directions relative to the length L of the tooth 47, starting from the center of the tooth arranged at L / 2, although in different embodiments there may also be an asymmetrical configuration having a first height H1 offset from the center relative to the length L of the tooth 47.

[0077] The reduction in height from the first height H1 to the second height H2, i.e. the difference D between the two heights of the tooth 47, is designed so that the tangent of the convex profile of the tooth 47 has an angle at the tapering end that is equal to or greater than the previously defined angle A of the maximum oscillation of the pinion 15. That is, the difference D between the first height H1 and the second height H2 is such that the tangent of the arched convex profile of the tooth 47 corresponding to the tapering end is inclined at an angle equal to or greater than the angle A relative to the axis 33 of the pinion 15.

[0078] As an example, for simplicity, an arc with a radius R is used to approximate ( Fig.12 ) the convex profile of the tooth 47, and the tangent T of the convex profile of the tooth 47 is imposed to be inclined at the end corresponding to the tooth 47 with an inclination equal to the angle A, thereby defining a difference D between the first height H1 and the second height H2, the following can be achieved:

[0079] D=H1-H2

[0080] L / 2=Rb*sin(A)→Rb=L / (2*sin(A))

[0081] D=Rb*(1-cos(A))→Rb=D / (1-cos(A))

[0082] D / (1-cos(A))=L / (2*sin(A))

[0083] D=L*(1-cos(A)) / (2*sin(A))

[0084] For example, by applying the formula to the case of a tooth 47 having a length L equal to 35 mm, we obtain:

[0085] - To ensure an oscillation equal to the angle A having a value of 0.5°, the value D must be equal to 0.076 mm;

[0086] - To ensure an oscillation equal to the angle A with a value of 1°, the value D must be equal to 0.153 mm;

[0087] - To ensure an oscillation equal to the angle A having a value of 2°, the value D must be equal to 0.305 mm;

[0088] - To ensure an oscillation equal to the angle A having a value of 3°, the value D must be equal to 0.458 mm;

[0089] - To ensure that the oscillation is equal to the angle A having a value of 4°, the value D must be equal to 0.611 mm.

[0090] For example, by applying the formula to the case of tooth 47 having a length L equal to 45 mm, we obtain:

[0091] - To ensure an oscillation equal to the angle A having a value of 0.5°, the value D must be equal to 0.098 mm;

[0092] - To ensure an oscillation equal to the angle A with a value of 1°, the value D must be equal to 0.196 mm;

[0093] - To ensure an oscillation equal to the angle A having a value of 2°, the value D must be equal to 0.393 mm;

[0094] - To ensure an oscillation equal to the angle A having a value of 3°, the value D must be equal to 0.589 mm;

[0095] - To ensure that the oscillation is equal to the angle A having a value of 4°, the value D must be equal to 0.786 mm.

[0096] For example, by applying the formula to the case of a tooth 47 having a length L equal to 30 mm, we obtain:

[0097] - To ensure an oscillation equal to the angle A having a value of 0.5°, the value D must be equal to 0.065 mm;

[0098] - To ensure an oscillation equal to the angle A with a value of 1°, the value D must be equal to 0.131 mm;

[0099] - To ensure an oscillation equal to the angle A having a value of 2°, the value D must be equal to 0.262 mm;

[0100] - To ensure an oscillation equal to the angle A having a value of 3°, the value D must be equal to 0.393 mm;

[0101] - To ensure that the oscillation is equal to the angle A having a value of 4°, the value D must be equal to 0.524 mm.

[0102] An important value for defining the parameters relevant to the present invention is the value of the difference D between the first height H1 and the second height H2, based on which the oscillation angle A is defined, but the absolute values ​​of the first height H1 and the second height H2 can be different and can be selected according to construction requirements, for example, the tolerances and robustness available from the processing machine.

[0103] By way of example, in the case of an oscillation of a tooth 47 of length L equal to 35 mm equal to an angle A having a value of 1°, the value D will be equal to 0.153 mm, such a value being achieved, for example, with values ​​of a first height H1 equal to 0.765 mm and a second height H2 equal to 0.612 mm, but it will be clear that the absolute values ​​of the first height H1 and the second height H2 may be different, in any case leading to the same difference D corresponding to the same oscillation angle A. It is possible to choose a higher value of the first height H1 to which a higher value of the second height H2 will correspond, so that the difference D is constant between the first height H1 and the second height H2, for example, in the case described, with the first height H1 equal to 0.773 mm and the second height H2 being 0.620 mm, a difference D equal to 0.153 mm is always obtained, and the angle A is 1°. A lower value of the first height H1 can be chosen, to which a lower value of the second height H2 will correspond, so that the difference D is constant between the first height H1 and the second height H2, for example, in the described case, the first height H1 is equal to 0.753 mm and the second height H2 is 0.600 mm, always obtaining a difference D value equal to 0.153 mm and an angle A of 1°.

[0104] The detail that allows the pinion 15 to freely undergo the previously described tilting according to the angle A is the convex shape of the second portion 42 in the form of a toothed wheel, forming an engagement for coupling with the first rim 17. This convex shape allows the indicated oscillations.

[0105] The first wheel rim 17 is supported by a support bearing 45 ( Fig. 9 ) on the cover 16, the support bearing is preferably a double row ball bearing. The support bearing 45 is held in its fixed position on the cover 16 by a corresponding flange 34 ( Figure 4 , Fig. 9 In this way, the first rim 17 is not subjected to oscillations, but due to its coupling with the floating and oscillating pinion 15, it is possible to obtain the desired effect of reducing the stresses due to possible mechanical deformations, with reduced wear and noise.

[0106] The previously described solution of inserting an O-ring 26 between the second rim 10 and the box 7 ( Figure 8 ) also helps reduce noise.

[0107] There is ( Fig. 9 ) of the fixing ring 29 is arranged ( Fig.11 ) in a housing 46 obtained on the pinion 15 itself and, as explained previously, which limits the axial movements of the pinion 15, which is therefore floating and not supported in a direct and constrained manner by any bearing, being free to move axially along its own axis 33 within the limits set by the fixing ring 29 and to tilt according to the angle A previously defined. Thus, the teeth 47 of the second portion 42 correspond to one end 48 of the pinion 15 and comprise a housing 46, wherein the housing 46 comprises a fixing ring 29, which is arranged inside the housing and extends circumferentially around the second portion 42, limiting the axial movements of the pinion 15 relative to the first rim 17.

[0108] For the purposes of the present invention, without limitation, embodiments of an electric traction vehicle according to the invention having a gear motor 5 thereon are a running machine, a forklift, a tractor. Finally, the present invention also relates to ( Fig.16 ) An electric traction vehicle 31 comprising at least one gear motor 5 according to the invention for direct transmission to the drive wheels of the electric traction vehicle.

[0109] Finally, the present invention relates to Figure 4 , Figure 7 ) for the gear motor 5 and the gear reduction device 4 for direct transmission to the drive wheels of the electric traction vehicle 31 ( Fig.16) of a corresponding gear motor 5, wherein the drive motor 6 is suitable for coupling with the gear reduction device 4 to form an assembly of the gear motor 5. The gear reduction device 4 comprises a support box 7 containing a planetary gear 2, which is provided with a drive input for coupling a motor shaft 8 of the traction motor 6. The gear reduction device 4 comprises a hub 1 for supporting a drive wheel. The gear 2 of the gear reduction device 4 comprises a first rim 17 of a first reduction stage and a planetary gear carrier 11, which is provided with planetary gears 12 reciprocally coupled by means of a pinion 15 for transmitting motion from the first rim 17 to the planetary gear carrier 11. The pinion 15 is an independent floating element, provided with a first toothed portion 41 for coupling to the planetary gear 12 of the planetary gear carrier 11, and a second portion 42 opposite to the first portion 41 in length extension relative to the pinion 15 along its own axis 33, wherein the second portion 42 is coupled to the first rim 17 via a spherical type groove joint 30, the coupling between the pinion 15 and the first rim 17 enabling the pinion 15 to freely move axially along its own axis 33 with axial movement relative to the first rim 17, and freely tilt on its axis 33.

[0110] The present invention also relates to a gear motor 5 for direct transmission to a drive wheel of an electric traction vehicle 31, wherein a traction motor 6 is connected to a gear reduction device 4 for forming an assembly of the gear motor 5, the gear reduction device 4 comprising a support box 7, the support box 7 containing a gear 2 of an epicyclic stage, the gear 2 of the epicyclic stage being provided with a drive input for connecting to a motor shaft 8 of the traction motor 6, wherein the motor 6 is provided with a corresponding motor shaft 8, the motor shaft being provided with a first end 27, which protrudes relative to the body of the traction motor 6 and is used to connect to the drive input of the gear reduction device 4, the gear reduction device 4 comprising a hub 1 for supporting a drive wheel, the gear 2 of the gear reduction device 4 comprising a first wheel rim 17 of a first reduction stage and a planetary gear carrier 11, the planetary gear carrier being provided with planetary gears 12 reciprocally coupled by means of a pinion 15 for transmitting movement from the first wheel rim 17 to the planetary gear carrier 11, wherein the gear reduction device 4 is manufactured according to the description.

[0111] The invention also relates to an electric traction vehicle comprising at least one gear motor 5 for direct transmission to a drive wheel of the electric traction vehicle 31, wherein the traction motor 6 is coupled to a gear reduction device 4 for forming an assembly of the gear motor 5, the gear reduction device 4 comprising a support box 7 containing a gear 2 of an epicyclic stage, the gear 2 of the epicyclic stage being provided with a drive input for coupling to a motor shaft 8 of the traction motor 6, wherein the motor 6 is provided with a corresponding motor shaft 8 provided with a first end 27 protruding relative to the body of the traction motor 6 for coupling to the drive input of the gear reduction device 4, the gear reduction device 4 comprising a hub 1 for supporting the drive wheel, the gear 2 of the gear reduction device 4 comprising a first wheel rim 17 of a first reduction stage and a planetary gear carrier 11, the planetary gear carrier being provided with planetary gears 12 reciprocally coupled by means of pinions 15 for transmitting movement from the first wheel rim 17 to the planetary gear carrier 11, wherein the gear reduction device 4 is manufactured according to the description.

[0112] The present invention has been described with reference to the accompanying drawings in preferred embodiments, but it is apparent that many possible changes, modifications and variations will be immediately apparent to those skilled in the art from the foregoing description. Therefore, it should be understood that the present invention is not limited to the foregoing description, but encompasses all such changes, modifications and variations according to the appended claims.

[0113] The naming used

[0114] With reference to the reference numerals reported in the accompanying drawings, the following nomenclature has been used:

[0115] 1. Wheel hub

[0116] 2. Gear

[0117] 3. Brakes or brake systems

[0118] 4. Gear reduction device

[0119] 5. Gear motor

[0120] 6. Motor

[0121] 7. Second housing or box

[0122] 8. Motor shaft

[0123] 9. Rim support plate

[0124] 10. Secondary rim or planetary rim

[0125] 11.Planetary gear bracket

[0126] 12. Planetary gear

[0127] 13. Ring nut

[0128] 14. Connecting end with first reduction stage

[0129] 15. Pinion or planetary pinion

[0130] 16. First support shell or first support cover

[0131] 17. First wheel rim or first reduction stage wheel rim

[0132] 18. The first chamber or chamber of a gear reduction device

[0133] 19.Connection seat

[0134] 20.Jointing elements

[0135] 21.First ball bearing

[0136] 22. Second needle roller bearing

[0137] 23. First groove

[0138] 24. Second groove

[0139] 25. Shell

[0140] 26.O-Ring

[0141] 27. First End

[0142] 28. Second End

[0143] 29. Fixed ring

[0144] 30. Connector

[0145] 31. Vehicles

[0146] 32.Wire spring or elastic ring

[0147] 33. Axis

[0148] 34. Flange

[0149] 35. Second roller bearing

[0150] 36.First roller bearing

[0151] 37. Motor cover

[0152] 38. Connectors

[0153] 39.Terminal Block

[0154] 40. Encoder

[0155] 41. Part I

[0156] 42. Part 2

[0157] 43. Part 3

[0158] 44. Tone wheel

[0159] 45.Support bearing

[0160] 46. ​​Shell

[0161] 47. Teeth

[0162] 48. The End

[0163] A.Angle

[0164] L. Length

[0165] H1. First height

[0166] H2. Second height

[0167] R. Radius

[0168] T. Tangent

[0169] D. Poor

Claims

1. A gear reduction device (4) for a gear motor (5) for directly driving a drive wheel of an electric traction vehicle (31), wherein: The traction motor (6) is intended to be connected to a gear reduction device (4) to form an assembly of a gear motor (5), the gear reduction device (4) comprising a support box (7), the support box (7) containing a gear (2) of an epicyclic stage, the epicyclic stage being provided with a drive input for connecting to a motor shaft (8) of the traction motor (6), the gear reduction device (4) comprising a hub (1) for supporting a drive wheel, the gear (2) of the gear reduction device (4) comprising a first rim (17) of a first reduction stage and a planetary gear carrier (11), the planetary gear carrier being provided with planetary gears (12) reciprocatingly coupled by means of a pinion (15) for transmitting movement from the first rim (17) to the planetary gear carrier (11), characterized in that: The pinion (15) is an independent floating element released from the hub (1) of the wheel and from the planetary gear carrier (11), the pinion (15) being provided with a first toothed portion (41) for coupling to the planetary gear (12) of the planetary gear carrier (11) and being provided with a second portion (42) extending opposite to the first portion (41) relative to the length of the pinion (15) along its own axis (33), wherein the second portion (42) is coupled to the first wheel rim (17) via a spherical type groove joint (30), the coupling between the pinion (15) and the first wheel rim (17) enabling the pinion (15) to freely move axially along its own axis (33) in a manner relative to the axial movement of the first wheel rim (17), and it to freely tilt on its axis (33).

2. The gear reduction device (4) according to the preceding claim, characterized in that: The pinion (15) is free to tilt on its axis (33) at an angle (A) between 0.5° and 4°, preferably between 1° and 2°.

3. The gear reduction device (4) according to any one of the preceding claims, characterized in that: The second portion (42) is made in the form of a coupling gear obtained on a surface having a cylindrical shape, wherein the teeth (47) of the gear protrude outwardly with an arched convex profile, the teeth (47) having a first height (H1) at the central part of the gear and tapering at the ends, while obtaining a second height (H2) near the end area of ​​the gear, wherein the second height (H2) is smaller than the first height (H1).

4. The gear reduction device (4) according to claims 2 and 3, characterized in that: The difference (D) between the first height (H1) and the second height (H2) is such that a tangent (T) to the arched convex profile of the tooth (47) near the tapered end is inclined at an angle equal to or greater than angle (A) relative to the axis (33) of the pinion (15).

5. The gear reduction device (4) according to the preceding claim, characterized in that: The difference (D) between the first height (H1) and the second height (H2) is calculated according to the formula D=L*(1-cos(A)) / (2*sin(A)), where L is the length of the second portion (42).

6. The gear reduction device (4) according to any one of the preceding claims 3 to 5, characterized in that: The teeth (47) of the second portion (42) include a housing (46) near the end (48) of the pinion (15), wherein the housing (46) includes a retaining ring (29) disposed within the housing and extending circumferentially around the second portion (42), the retaining ring (29) limiting the axial movement of the pinion (15) relative to the first edge (17).

7. The gear reduction device (4) according to any one of the preceding claims, characterized in that: The first wheel rim (17) is supported by a support bearing (45).

8. The gear reduction device (4) according to any one of the preceding claims, characterized in that: The gear (2) comprises a second wheel rim (10) of an epicyclic stage, wherein the second wheel rim (10) is fixed to a support box (7) of a gear reduction device (4) via a wheel rim support disc (9), and the wheel rim support disc is connected to the second wheel rim (10) via a wire spring (32) or an elastic ring.

9. The gear reduction device (4) according to the preceding claim, characterized in that: The second rim (10) is provided with two grooves (23, 24), each of which contains a corresponding O-ring (26) for damping vibrations transmitted from the second rim (10) to the box (7). The second rim (10) and the box (7) are not in direct contact with each other, but the second rim (10) is supported on the box (7) by inserting the O-ring (26).

10. A gear motor (5) for directly driving a drive wheel of an electric traction vehicle (31), wherein: A traction motor (6) is connected to a gear reduction device (4) to form a component of a gear motor (5), wherein the motor (6) is provided with a corresponding motor shaft (8), and the motor shaft is provided with a first end (27), which protrudes relative to the main body of the traction motor (6) for connecting to the drive input end of the gear reduction device (4), characterized in that the gear reduction device (4) is manufactured according to any one of the above claims.

11. The gear motor (5) according to the preceding claim, characterized in that: The box (7) of the gear reduction device (4) is a structural support box, intended to be fixed to an electric traction vehicle, constituting the body of the gear reduction device, the box (7) defining at least a first chamber (18) or chamber of the gear reduction device, the traction motor (6) having its own support housing, the support housing constituting the body of the motor, the body being fixed to the box (7) as a cover (16), the box (7) and the cover (16) constituting a single structural support housing (25) of the gear motor (5), the cover (16) covering and enclosing the gear reduction device (4) in the box (7) ), removal of the cover (16) allows free access to the gear reduction device (4) on one side and free access to the motor (6) on the opposite side, wherein the motor (6) is connected to the gear reduction device (4) via the first connecting end (27) of the motor shaft (8), the connection between the motor (6) and the gear reduction device (4) occurring without inserting additional transmission drive elements, while obtaining a direct connection between the motor (6) and the gear reduction device (4), wherein the transmission shaft of the motor (6) is directly connected to the drive input end of the gear (2) of the gear reduction device (4).

12. The gear motor (5) according to the preceding claim, characterized in that: The motor shaft (8) is machined at the first end (27) for coupling to the first wheel rim (17), while obtaining meshing teeth (20) intended for coupling to corresponding counter-teeth of the first wheel rim (17).

13. The gear motor (5) according to any one of the preceding claims 10 to 12, characterized in that: The motor shaft (8) comprises a coupling device with a brake system (3) near a second end (28), which is the opposite end of the motor shaft (8) relative to the first end (27), the motor shaft thus comprising: i) a motor shaft of the motor (6); ii) one of the input gears of the gear reduction device (4); iii) A connection for applying the system brake system (3).

14. The gear motor (5) according to the preceding claim, characterized in that: The braking system (3) is an electromagnetic type brake.

15. The gear motor (5) according to any one of the preceding claims 10 to 14, characterized in that: The motor (6) is a high-speed motor having a maximum rotational speed of the order of 8000-12000 RPM.

16. The gear motor (5) according to any one of the preceding claims 10 to 15, characterized in that: The body of the motor (6) is placed in a misaligned position relative to the body of the gear reduction device (4) and is intended to be positioned in a higher position relative to the position of the gear reduction device (4) when the gear motor (5) is mounted on the vehicle, the term higher referring to the position relative to the ground when the gear motor (51) is mounted on the vehicle.

17. An electric traction vehicle, characterized in that: It comprises at least one gear motor (5) for directly driving the drive wheels of an electric traction vehicle (31), wherein the traction motor (6) is coupled to a gear reduction device (4) forming an assembly of the gear motor (5), characterized in that: A gear reduction device (4) manufactured according to any one of claims 1 to 9.

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