Electric propulsion device for a motor vehicle for generating sound
By introducing a harmonic oscillator into the propulsion device of an electric vehicle, the oscillation of magnets and elastic elements generates sound pressure waves, the problem of the electric vehicle motor making unpleasant sounds is solved, and a more comfortable driving experience is achieved.
Patent Information
- Application Number
- CN202411415308.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-10-13
- Filing Date
- 2024-10-11
- Publication Date
- 2025-04-15
AI Technical Summary
The electric motor of the electric vehicle makes unpleasant sounds, affecting driver engagement and understanding of the vehicle's operating conditions.
At least one harmonic oscillator is introduced into the propulsion device of an electric vehicle, and the oscillation of the magnet and the elastic element generates a sound pressure wave, and combines the sound characteristics of a traditional internal combustion engine to generate a comfortable low-frequency sound.
By introducing a harmonic oscillator, the driver perceived sound quality of electric vehicles is improved, driver participation is increased, and the sound is similar to that of traditional internal combustion engine vehicles and is more comfortable.
Smart Images
Figure CN119821101A_ABST
Abstract
Description
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This patent application claims the priority of Italian Patent Application No. 102023000021336 filed on October 13, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field
[0003] The present invention relates to an electric propulsion device for a motor vehicle and more particularly to the sound emitting aspects of the device. Background Art
[0004] Some motor vehicles use only electric motors as a means of propulsion and are therefore often referred to as fully electric vehicles or simply electric vehicles.
[0005] During their operation, electric motors emit sounds that are often considered to be subtle or even unpleasant.
[0006] In fact, in the field of motor vehicles, the electric motors used are generally electric motors adapted to rotate at relatively high speeds in order to limit volume and weight; therefore, the sound produced has an intensity that becomes relatively large in the high-frequency range.
[0007] Therefore, the overall resulting sound is perceived by the human ear as an unpleasant ringing sound.
[0008] This has a negative impact on the driver, as the driver is less involved in driving, less aware of the operating status of the motor, or even disturbed by unpleasant sounds.
[0009] Therefore, there is a need to improve the quality of sound perceived by a driver of an electric vehicle, particularly to increase the driver's engagement and understanding of the operating conditions of the motor vehicle.
[0010] It is an object of the present invention to respond to the above needs, preferably in a simple and reliable manner. Summary of the invention
[0011] This object is achieved with a propulsion device according to claim 1 .
[0012] The dependent claims define particular embodiments of the invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Below, embodiments of the present invention are described by way of non-limiting examples and with reference to the accompanying drawings for a better understanding of the present invention, in which:
[0014] - Figure 1 is a perspective view of a motor vehicle comprising a propulsion device according to the invention,
[0015] - Figure 2 is a perspective view of a portion of the propulsion device on an enlarged scale and with some parts removed for clarity;
[0016] - Figure 3 is based on Figure 2 A cross section of the propulsion device in a plane section defined by line III-III,
[0017] - Figure 4 and Figure 5 Is detailed Figure 3 and corresponding to two respective different operating conditions of the propulsion device,
[0018] - Figure 6 and Figure 7 Similar to Figure 4 and Figure 5 , but some of these elastic components are shown in schematic form,
[0019] - Figure 8 This is a diagram of the positioning of some of the magnets in the propulsion device.
[0020] - Fig. 9 yes Figure 8 A diagram of the positioning variants, and
[0021] - Figures 10 to 12 yes Figure 8 and Fig. 9 FIG. 4 is a diagram of another variation of positioning in FIG. DETAILED DESCRIPTION
[0022] exist Figure 1 In the drawings, reference numeral 1 is used to denote a motor vehicle as a whole.
[0023] Generally, a motor vehicle 1 has a body 2 , a plurality of wheels 3 , and a suspension assembly, not shown, configured to suspend the body 2 relative to the wheels 3 .
[0024] The wheels 3 represent known traction means for moving the motor vehicle 1 , but for the purposes of the present invention they may be replaced by any other suitable means, even by unusual means such as track-type means.
[0025] The motor vehicle 1 further comprises an electric motor 5 and in particular a transmission assembly 6 for propelling the motor vehicle 1 .
[0026] The electric motor 5 is therefore part of the propulsion device of the motor vehicle 1 .
[0027] The electric motor 5 is configured to transmit mechanical power; the transmission assembly 6 is configured to transmit the mechanical power to the two wheels 3 to move the motor vehicle 1 .
[0028] The transmission assembly 6 may also be configured to transmit mechanical power to all wheels 3 , or more generally, to the traction means of the motor vehicle 1 .
[0029] Optionally, the transmission assembly 6 may also have the function of reducing the output speed of the motor 5 , so that the wheel 3 rotates at a rotation speed reduced relative to the output speed of the motor 5 .
[0030] During operation of the motor 5 , ie when the motor 5 delivers mechanical power, the motor 5 emits a rotating magnetic field.
[0031] More specifically, the motor 5 has a rotor 7 and a stator 8 which are coaxial with each other around a rotor axis R.
[0032] The stator 8 or the rotor 7 is supplied with electric current, so that a magnetic interaction occurs with a magnetic element of the other (the stator 8 or the rotor 7 ).
[0033] The magnetic interaction corresponds to a rotating magnetic field which is responsible for the rotation of the rotor 7 about the rotor axis R relative to the stator 8 .
[0034] The magnetic principles associated with the operation of electric motors are generally known, so they are not explained in further detail here. In particular, the electric motor generates a rotating magnetic field which is the basic principle of the operation of the electric motor.
[0035] The magnetic field generated by the motor 5 rotates about the rotor axis R, ie it follows the direction of rotation of the rotor 7 .
[0036] More specifically, a magnetic field is formed between two opposing magnetic poles that are ideally connected by a magnetic axis.
[0037] Here, the magnetic axis is perpendicular to the rotor axis R and rotates around the rotor axis R on a plane perpendicular to the rotor axis R.
[0038] Thus, "magnetic axis" refers to the axis extending between the two poles of a magnet or magnetic field.
[0039] The rotor 7 extends axially along the axis R between two axial ends 7a, 7b and has an intermediate portion 7c along the axis R between the ends 7a, 7b.
[0040] At least the intermediate portion 7 c interacts magnetically with the stator 8 according to a radial direction relative to the axis R. The intermediate portion 7 c therefore defines a radial magnetic interaction portion of the rotor 7 .
[0041] The portion 7b is clearly fixed to the middle portion 7c.
[0042] The rotor 7 preferably comprises magnets 10 , in particular permanent magnets, having a magnetic axis radial to the axis R. In other words, the magnets 10 have, along a radial direction relative to the axis R, two opposite magnetic poles.
[0043] In particular, the magnet 10 is part of the end 7b or is supported by the end 7b in a fixed manner relative to the end 7b. More specifically, the portion 7b may be defined by the magnet 10.
[0044] In the embodiment shown, the magnet 10 is part of a disk fixed to the end 7 b and with which the rotor 7 ends axially, on the side of the end 7 b, along the axis R. The magnet 10 may alternatively also be defined by the above-mentioned disk, or more generally by a body fixed to the end 7 b and with which the rotor 7 ends axially, along the axis R, on the side of the end 7 b.
[0045] With respect to the magnetic axis of the magnet 10, alternatively, the magnet 10 may have a magnetic axis parallel to the axis R and eccentrically arranged (i.e., radially spaced apart from the axis R) so as to have two magnetic poles, one of which is exposed at the end 7a, i.e., axially toward the interior of the motor 5, and the other magnetic pole is exposed in the opposite direction (i.e., axially toward the outside of the motor 5).
[0046] In addition, in the latter case, the rotor 7 may preferably include another magnet 10 having a magnetic axis parallel to the axis R, which is arranged, for example, in a position diametrically opposite to the previous magnet 10 and, more precisely, in the same radial direction (i.e., preferably in a position aligned in a straight radial direction). Here, this other magnet 10 will have a magnetic pole opposite to that of the previous magnet 10.
[0047] Obviously, the rotor 7 can even include a plurality of magnets 10 having respective magnetic axes parallel to the axis R and arranged, for example, in a circumferential distribution, in particular wherein two halves of the magnet 10 are arranged around the axis R along respective adjacent circumferential halves and wherein the magnetic poles of one half of the magnet 10 are opposite relative to the magnetic poles of the other half.
[0048] In any case, the magnetic field generated by the one or more magnets 10 will in any case be a rotating magnetic field (because these magnets 10 will be fixed or integrated into the rotor 7), and will in any case be the magnetic field emitted by the motor 5 during its operation (because it belongs to the motor 5).
[0049] Therefore, the magnet 10 may not even be included, so that the rotating magnetic field emitted by the motor 5 will consist of the magnetic field generated by the magnetic interaction between the rotor 7 and the stator 8.
[0050] According to the invention, the propulsion device of the motor vehicle 1 comprises, in addition to the electric motor 5 , at least one harmonic oscillator 11 .
[0051] In this case, the propulsion device also comprises two further harmonic oscillators 12 , 13 .
[0052] Each of the harmonic oscillators 11 , 12 , 13 comprises at least one corresponding support 14 which may be fixed, for example, to the outer casing of the electric motor 5 .
[0053] Furthermore, the harmonic oscillators 11 , 12 , 13 comprise respective magnets 15 , 16 , 17 , in particular permanent magnets, and respective elastic elements 18 suspending the magnets 15 , 16 , 17 on the support 14 .
[0054] Each of the magnets 15 , 16 , 17 is arranged relative to the motor 5 to have a corresponding magnetic pole exposed to the rotating field emitted by the motor 5 .
[0055] As previously mentioned, the rotating field emitted by the motor 5 may be or may include a magnetic field generated by one or more magnets 10, a magnetic field generated by the interaction between the rotor 7 and the stator 8, or even a combination of these two magnetic fields.
[0056] In more detail, the magnets 15, 16, 17 have respective magnetic axes parallel to the axis R, so that the poles rotate axially towards the rotor 7. However, this does not generally exclude that the magnets 15, 16, 17 can have their poles rotated radially towards the axis R, i.e. the magnetic axes are radial relative to the axis R.
[0057] Thus, magnets 15, 16, 17 are arranged opposite rotor 7 according to axis R. In other words, magnets 15, 16, 17 face one or more magnets 10 according to axis R; alternatively or additionally, magnets 15, 16, 17 may be arranged radially around rotor 7 or axis R.
[0058] Conveniently, according to an alternative not shown, the harmonic oscillators 11 , 12 , 13 may comprise respective guide means 19 configured to guide the magnets 15 , 16 , 17 respectively along their magnetic axes or in detail parallel to the axis R or even radially relative to the axis R.
[0059] By means of the elastic element 18 , the magnets 15 , 16 , 17 oscillate relative to the support 14 according to the rotating magnetic field to which they are exposed or subjected.
[0060] In this way, the oscillation of the magnets 15, 16, 17 causes sound pressure waves. In fact, the vibration of the elastic element 18 or even the movement of the surrounding air caused by the movement of the magnets 15, 16, 17 makes the air vibrate so that sound pressure waves are generated and propagated through the air.
[0061] At least one of the harmonic oscillators 11, 12, 13 preferably has a natural frequency that is different from the natural frequency of another of the harmonic oscillators 11, 12, 13. More preferably, the natural frequencies of the harmonic oscillators 11, 12, 13 are all different from each other.
[0062] Thus, the frequencies of the sound pressure waves generated by the oscillations of the magnets 15, 16, 17 will all be different from one another, even when subjected to the same rotating magnetic field.
[0063] In fact, the harmonic oscillators 11, 12, 13 can be mathematically modeled as having at least a respective stiffness and mass, of which the natural frequency is a function. In fact, the natural frequency is defined as the square root of the ratio of stiffness to mass.
[0064] Therefore, the masses and / or stiffnesses of the harmonic oscillators 11 , 12 , 13 may each be different from one another, so that the corresponding natural frequencies are different from one another.
[0065] Each magnet 15 , 16 is arranged independently of one another substantially at a diametrically opposite position of the magnet 17 relative to the axis of rotation of the rotating magnetic field (here specifically coinciding with the rotor axis R).
[0066] More preferably, the magnets 15, 16 may be advantageously arranged at positions aligned along a linear axis, in particular a radial linear axis.
[0067] In fact, more generally, "diametrically opposite positions" do not necessarily refer to positions aligned along a linear axis, but positions having at least one angular distance greater than a right angle or in particular greater than or equal to 120°, more preferably greater than or equal to 135°.
[0068] exist Fig. 9 In a variant of , the propulsion device comprises an additional harmonic oscillator 20 with its support 14, its elastic element 18 and a magnet 21 arranged diametrically opposite the magnet 16. More precisely, but not necessarily, the magnets 16, 21 are aligned along a rectilinear direction, in particular perpendicular to the axis R and radial with respect to it.
[0069] exist Fig.10In a variant, the magnets 16, 17 or more generally the harmonic oscillators 12, 13 are positioned so that they are aligned along a rectilinear direction, in particular perpendicular to the axis R and radial to the axis R; here, the magnet 15 and the corresponding harmonic oscillator 11 are not included.
[0070] The alignment of the magnets 16, 17 is advantageous because it allows the generation of a sound with a period equal to the inverse of the time taken for the rotor 7 to complete one rotation. The timing of the sound generation thus substantially follows the operating speed of the motor 5.
[0071] Fig.11 A variation similar to Fig.10 A variation of the invention in which a magnet 15 and a corresponding harmonic oscillator 11 are added at an angular distance closer to the magnet 16 (particularly less than 60°). Here, the sound produced by the harmonic oscillator 11 will have a slight phase delay relative to the sound produced by the other two harmonic oscillators 12 and 13.
[0072] Fig.12 A variation similar to Fig.11 A variation in which a magnet 21 and a corresponding harmonic oscillator 20 are added, which are positioned so that they are aligned relative to the magnet 15 and the corresponding harmonic oscillator 11 along a straight direction (in particular, perpendicular to the axis R and radially relative to the axis R).
[0073] The magnets 15, 16 preferably have corresponding poles (the poles facing the one or more magnets 10) exposed to the rotating magnetic field, which have relative Fig. 9 and Fig.12 The exposed magnetic poles of the magnets 17 or magnets 21 in the embodiment (facing toward one or more magnets 10) are equal and opposite in respective polarity.
[0074] In this way, based on the rotation of the magnet 10 or the rotating magnetic field of the motor 5 , all the magnets 15 , 16 , 17 , 21 will be subject to an attractive force toward the magnet 10 (or the motor 5 ) or a repulsive force toward the magnet 10 (or the motor 5 ).
[0075] For example, assuming that magnets 15 and 16 expose their north poles toward the rotating magnetic field, magnets 17 and 21 will expose their south poles toward the same rotating magnetic field. On the other hand, the rotating magnetic field has two opposite magnetic poles, so that the north poles of magnets 15 and 16 will face the north pole or south pole of the rotating magnetic field so as to be subjected to the repulsive magnetic force or the attractive magnetic force, respectively, and the south poles of magnets 17 and 21 will face the south pole or north pole of the rotating magnetic field so as to be subjected to the repulsive magnetic force or the attractive magnetic force, respectively. Therefore, all magnets 15, 16, 17, and 21 are attracted or repelled by motor 5.
[0076] The speed of alternation between attraction and repulsion will be determined by the speed of the motor 5 , or more precisely, by the angular speed of the rotor 7 .
[0077] Therefore, the frequency of the externally exerted magnetic force on the harmonic oscillator 11 , 12 , 13 , 20 will correspond to the frequency of rotation of the motor 5 , or more precisely to the frequency of rotation of the rotor 7 , precisely due to the alternation between attraction and repulsion.
[0078] Therefore, the frequency of the sound pressure wave will also be particularly positively correlated with the frequency of the externally applied magnetic force and thus with the operating state of the motor 5 .
[0079] Each elastic element 18 preferably independently comprises an axially deformable elastic tubular body (here deformable in a direction parallel to the axis R), which is preferably of the bellows type ( Figure 4 and Figure 5 ).
[0080] However, this is not necessary, since the elastic element 18 may comprise any elastic body suitable for achieving the oscillation of the magnets 15, 16, 17. Figure 6 and Figure 7 In FIG. 1 , the elastic element 18 is generally represented as a spring.
[0081] Figure 4 and Figure 6 shows the attraction between magnet 16 and magnet 10, and Figure 5 and Figure 7 The repulsion between magnet 16 and magnet 10 is shown.
[0082] The elastic tubular body is fixed on a corresponding support 14, and the support 14 particularly has a through hole communicating with the interior of the tubular body.
[0083] The tubular body has two opposite axial ends, one of which is communicated with the through hole of the support member 14 and the other is fixed to a magnet thereof between the magnets 15 , 16 , 17 .
[0084] The propulsion device preferably further comprises a sound transmission device 22 configured to transmit the sound pressure waves generated by the harmonic oscillators 11, 12, 13 to a passenger compartment of the motor vehicle 1. The passenger compartment is defined by the body 2 and comprises at least one seat for a driver of the motor vehicle 1.
[0085] In particular, the sound transmission device 22 includes a plurality of tubes 23 having ends 23 a arranged at the harmonic oscillators 11 , 12 , 13 , respectively, so that the tubes 23 can receive the sound pressure waves generated by the harmonic oscillators 11 , 12 , 13 as input.
[0086] Furthermore, the tubes 23 extend from the ends 23a until terminating in respective ends 23b, in particular the ends 23b coincide with each other. In fact, the tubes 23 are connected to each other to form a single common tube section 23c defined from the connection point until the ends 23b.
[0087] The end 23b communicates with the passenger compartment, so that in particular it opens into the passenger compartment.
[0088] Therefore, the sound pressure waves are transmitted to the passenger compartment through the duct 23 .
[0089] Alternatively or additionally, the transmission device 22 may include one or more speakers along the path of the sound pressure waves toward the passenger compartment. The speakers may have the function of conditioning the sound pressure waves, for example, amplifying them and / or adjusting the timbre of the sounds associated with these waves.
[0090] The transmission device 22 may even alternatively or additionally comprise a sound reproduction system.
[0091] Such a sound reproduction system may have: a sound pressure sensor configured to detect the sound pressure waves caused by the harmonic oscillators 11, 12, 13 and generate a corresponding sound signal (e.g., an electrical signal); an optional adjustment device configured to adjust the sound signal; and a speaker device configured to reproduce a sound corresponding to the sound signal (optionally, the adjusted sound signal).
[0092] The sound reproduction system may be combined with a sound enclosure in the sense that the sound pressure sensor detects sound pressure waves which are amplified or conditioned by the sound enclosure.
[0093] The sound box may also be integrated with the tube 23 , for example.
[0094] The tubular body of the elastic element 18 is in communication with the end portion 23 a so that the pressure wave directly generated inside the tubular body is transmitted to the tube 23 .
[0095] More specifically, the communication between the tubular body and the tube 23 occurs via the through hole of the support 14 to which the tube 23 is connected. The end 23a is fixed to the support 14, in particular on the side axially opposite to the tubular body. Therefore, in detail, the support 14 is arranged between the tubular body and the tube 23.
[0096] From the above, the advantages of the propulsion device according to the present invention are clear.
[0097] The harmonic oscillators 11, 12, 13 generate a pleasant sound corresponding to the low angular velocity of the rotor 7 for low operating conditions of the motor 5. In fact, the sound has a low frequency and high intensity comparable to the sound generated by a vehicle provided with an internal combustion engine.
[0098] In addition, the frequency of the sound will increase as the number of revolutions of the motor increases, because the frequency of the externally applied magnetic force causing the oscillation of the magnets 15, 16, 17 increases.
[0099] This aspect is obviously also reminiscent of what happens with the sound produced by a conventional internal combustion engine.
[0100] The solution adopted is simple since it does not require complex components but uses the same magnet operating principle as the electric motor 5 .
[0101] In fact, the approach adopted can be applied to basically any type of electric motor and any type of hybrid or electric vehicle.
[0102] The possibility of varying the natural frequencies of the harmonic oscillators 11 , 12 , 13 guarantees great versatility and the possibility to very carefully design the reproduced sounds which can also have harmonic contributions enriched in frequencies so as to be attractive and pleasing to the driver.
[0103] Finally, it is clear that changes may be made to the propulsion device according to the invention and to variants thereof without, in any case, departing from the scope of protection defined by the claims.
[0104] In particular, the number and shapes of the components described and shown may differ.
[0105] Furthermore, the described and illustrated variants and embodiments may be combined with one another without departing from the scope of protection defined by the claims.
Claims
1. A propulsion device for a motor vehicle (1), the device comprising: - an electric motor (5) configured to generate a rotating magnetic field during operation, and - at least one harmonic oscillator (11, 12, 13) arranged to interact with the rotating magnetic field emitted by the electric motor (5), The harmonic oscillator (11, 12, 13) comprises at least one support (14), a first magnet (15, 16, 17, 21) and an elastic element (18), wherein the first magnet (15, 16, 17, 21) is arranged to have a first magnetic pole exposed to a rotating magnetic field emitted by the electric motor (5), and the elastic element (18) suspends the first magnet (15, 16, 17, 21) to the support (14), so that the first magnet (15, 16, 17, 21) oscillates relative to the support (14) according to the rotating magnetic field, thereby causing sound pressure waves corresponding to the oscillations of the first magnet (15, 16, 17, 21) and the elastic element (18).
2. A device according to claim 1, wherein the electric motor (5) comprises a rotor (7) and a stator (8) coaxially around a rotor axis (R), the rotor (7) being rotatable relative to the stator (8) around the rotor axis (R), and comprising a second magnet (10) having a magnetic axis radial to the rotor axis (R), the second magnet (10) facing axially towards the first magnetic pole according to the rotor axis (R).
3. The device according to claim 2, wherein the rotor (7) comprises a radial magnetic interaction portion (7c) and an axial end portion (7b), wherein the radial magnetic interaction portion (7c) is configured to magnetically interact with the stator (8) according to a radial direction relative to the rotor axis (R), and the axial end portion (7b) comprises the second magnet (10) or is defined by the second magnet (10) according to the rotor axis (R) and is fixed relative to the radial magnetic interaction portion (7c).
4. The device according to claim 1, further comprising an additional harmonic oscillator (11, 12, 13, 20) having a third magnet (15, 16, 17, 21), the third magnet being arranged to have a second magnetic pole exposed to the rotating magnetic field emitted by the electric motor (5).
5. The device according to claim 4, wherein the harmonic oscillators (11, 12, 13, 20) have natural frequencies that are different from each other.
6. A device according to claim 4, wherein the third magnet (15, 16, 17, 21) is arranged to have a position diametrically opposite to the first magnet (15, 16, 17, 21) relative to the rotation axis (R) of the rotating magnetic field, and wherein the second magnetic pole has a magnetic polarity opposite to that of the first magnetic pole.
7. The device according to claim 1, comprising a sound transmission device (22) configured to transmit the sound pressure waves to a passenger compartment of the motor vehicle (1).
8. The device according to claim 7, wherein the sound transmission device (22) comprises a tube (23) having a first end (23a) arranged at the harmonic oscillator (11, 12, 13), and the tube (23) is configured to extend upward to terminate at another end (23b) connected to the passenger compartment.
9. Device according to claim 8, wherein the elastic element (18) comprises an axially deformable elastic tubular body, preferably of the bellows type, which is connected to the first end (23a) of the tube (23) and is carried by it.
10. A motor vehicle (1) comprising a propulsion device according to claim 1.