Powertrain structure of an automobile

Abstract

The utility model provides a kind of power assembly structure of automobile. The power assembly structure of the automobile has the rotating unit of the crankshaft of containing engine and the rotating shaft of rotating electric machine, the crankshaft is directly connected with the rotating shaft, and the elastic component is provided inside the rotating electric machine, and the components constituting the rotating unit are elastically connected with each other by the elastic component. Based on the structure, neither the power device volume increases, nor can the rotating unit containing crankshaft and rotating electric machine shaft resonate.

Description

Technical Field

[0001] This utility model relates to a powertrain structure for automobiles. Background Technology

[0002] In the prior art, one type of powertrain (also known as power transmission system) structure for automobiles features a direct connection between the engine crankshaft and the rotating shaft (hereinafter referred to as the rotating motor shaft) of a rotary electric machine (such as an electric generator). This type of powertrain is often used in the drive systems of hybrid electric vehicles or range-extended electric vehicles (electric vehicles equipped with a generator engine).

[0003] However, the existing technology of directly connecting the crankshaft and the rotary motor shaft has the following technical problems. Specifically, when the engine is running, the crankshaft and the rotary motor shaft rotate as a unit. If the natural vibration frequency of the rotating unit, which includes the crankshaft and the rotary motor shaft, coincides with the engine's vibration frequency, the rotating unit will resonate, causing the entire rotating unit to vibrate significantly. Furthermore, this significant vibration of the rotating unit will be transmitted to the vehicle body, causing discomfort to the occupants.

[0004] As a solution to the above problems, one could consider increasing the size of the mounting components of the engine or rotating electric motor (such as rubber mounts), or placing weights on the engine or rotating electric motor to change the natural vibration frequency of the rotating unit, causing it to move away from the engine's vibration frequency range. However, this would increase the size of the power unit, making it difficult to ensure sufficient installation space. Therefore, this solution lacks practicality. Utility Model Content

[0005] In view of the above situation, the purpose of this utility model is to provide a powertrain structure for automobiles that does not increase the size of the power unit and prevents resonance in the rotating unit containing the crankshaft and the rotating motor shaft.

[0006] As a technical solution to the above-mentioned technical problems, the present invention provides a powertrain structure for automobiles. The powertrain structure of the automobile includes a rotating unit comprising a crankshaft of an engine and a rotating shaft of a rotary motor. The crankshaft is directly connected to the rotating shaft. The feature is that an elastic component is provided inside the rotary motor, and the elastic component elastically connects the components constituting the rotating unit to each other.

[0007] The advantage of the powertrain structure of this invention, which has the above-described structure, is that it neither increases the size of the powertrain nor causes resonance in the rotating unit containing the crankshaft of the engine and the rotating shaft of the rotary motor. Specifically, since the components constituting the rotating unit (such as the rotating shaft and rotor of the rotary motor described later) are elastically connected to each other by elastic members, the natural vibration frequencies of these components can be set to values ​​different from those when they are directly connected to each other (without elastic members). Therefore, by adjusting the natural vibration frequencies to be outside the range of the engine's vibration frequency, resonance in the rotating unit can be prevented. In addition, the elastic members and the components connected to them (the components constituting the rotating unit) can act together as dynamic dampers, that is, the vibration of the dynamic damper is used to suppress (cancel) the vibration (resonance) of the crankshaft and the rotating shaft. Furthermore, since the components for suppressing the vibration of the rotating unit are housed inside the rotary motor, the size of the powertrain is not increased.

[0008] In addition, in the powertrain structure of the automobile described above, it is preferred that the elastic component is a rubber damper, which is disposed between the rotating shaft and the rotor of the rotary motor.

[0009] Based on this structure, the elastic component and the rotor can work together to act as a dynamic damper. That is, the vibration generated by the elastic component and the rotor can be used to suppress (counteract) the vibration of the crankshaft and the rotating shaft, thereby suppressing the vibration of the entire rotating unit.

[0010] Furthermore, in the powertrain structure of the automobile described above according to this utility model, it is preferable that the automobile is a range-extended electric vehicle.

[0011] Range-extended electric vehicles (REEVs) are electric vehicles equipped with a generator. When the battery charge is low, the generator may repeatedly start and stop. If the vibration frequency corresponding to the repeated rise and fall of the engine speed accompanying the engine's start and stop coincides with the natural vibration frequency of the rotating unit at a certain moment, the rotating unit will resonate, causing significant vehicle body vibration. To address this, this invention uses elastic components to elastically connect the components constituting the rotating unit, preventing resonance and thus achieving a REEV with less vehicle body vibration. Attached Figure Description

[0012] Figure 1 This is a schematic diagram showing the general structure of the automotive powertrain in an embodiment of the present invention.

[0013] Figure 2 This is a cross-sectional view showing the internal structure of the generator in an embodiment of this utility model.

[0014] Figure 3This is a cross-sectional view showing the internal structure of the generator in a modified example of this utility model. Detailed Implementation

[0015] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In this embodiment, the present invention will be applied to a range-extended electric vehicle as an example, and the rotor of the generator (rotary motor) and the rubber damper (elastic component) will work together to act as a dynamic damper.

[0016] Figure 1 is a schematic diagram showing the general structure of the vehicle powertrain in this embodiment. As shown in Figure 1, the vehicle powertrain in this embodiment includes a rotating unit comprising a crankshaft 2 of an engine (internal combustion engine) 100 and a rotating shaft 210 of a generator 200, and adopts a structure in which the crankshaft 2 and the rotating shaft 210 are directly connected.

[0017] Engine 100 is a tandem four-cylinder type. Multiple parts of the crankshaft 2 of engine 100 are rotatably supported by the cylinder block 1. The crankshaft 2 is connected to the piston 4 via connecting rod 3.

[0018] The crankshaft 2 includes a journal 22 rotatably supported by the cylinder block 1 and a crank pin 21 swayably supporting the connecting rod 3. The journal 22 is rotatably supported on the cylinder block 1 by a bearing shell 9, which acts as a sliding bearing.

[0019] When the engine 100 is running, the energy generated by the combustion of the mixture of gas (fuel and air) in the combustion chamber causes the piston 4 to reciprocate. This reciprocating motion is converted into the rotational motion of the crankshaft 2 through the connecting rod 3. The crankshaft 2 transmits the rotational force to the rotating shaft 210 of the generator 200.

[0020] The engine 100 is controlled by an engine electronic control unit (ECU) (not shown). Since the vehicle in this embodiment is a range-extended electric vehicle, the engine 100 is used solely as a power source for electricity generation. That is, when the battery charge is below a specified value, the engine 100 starts, causing the crankshaft 2 to transmit rotational force to the rotating shaft 210 of the generator 200. The driven generator 200 then generates electricity to charge the battery.

[0021] Figure 2 is a cross-sectional view showing the internal structure of the generator 200 in this embodiment. As shown in Figure 2, an annular stator 230 and a rotor 240 disposed on the inner diameter side of the stator 230 are provided inside the housing 220 of the generator 200. There is a predetermined distance, i.e., an air gap, between the inner circumferential surface of the stator 230 and the outer circumferential surface of the rotor 240.

[0022] An opening 222 is provided on the wall 221 of the housing 220 on the side near the engine 100, for a rotating shaft 210, which is directly connected to the crankshaft 2, to pass through. A radial bearing 223 is mounted on the inner diameter side of the opening 222. The radial bearing 223 rotatably supports the rotating shaft 210.

[0023] In this embodiment, both the rotating shaft 210 and the rotor 240 are components constituting the aforementioned rotating unit. A cylindrical rubber damper 250 is sandwiched between the rotating shaft 210 and the rotor 240. The outer diameter of the rubber damper 250 is the same as the inner diameter of the rotor 240, and the entire outer circumferential surface of the rubber damper 250 is bonded to the entire inner circumferential surface of the rotor 240. Simultaneously, the inner diameter of the rubber damper 250 is the same as the outer diameter of the rotating shaft 210, and the entire inner circumferential surface of the rubber damper 250 is bonded to the outer circumferential surface of the rotating shaft 210. Therefore, the rotating shaft 210 and the rotor 240 can be rotatably connected together via the rubber damper 250.

[0024] There are no particular restrictions on the type of rubber used to form the rubber damper 250. For example, natural rubber, nitrile rubber, neoprene rubber, fluororubber, silicone rubber, polyurethane rubber, etc. can be used.

[0025] In this embodiment, the vibration of the rotating unit containing the crankshaft 2 and the rotating shaft 210 is suppressed by having the rotor 240 and the rubber damper 250 work together as a dynamic damper. To this end, the type and shape (thickness, etc.) of the rubber of the rubber damper 250, which can make the natural vibration frequency of the dynamic damper basically consistent with the target frequency (the resonant frequency of the crankshaft 2 and the rotating shaft 210), were determined through experiments and simulations.

[0026] As mentioned above, under normal circumstances, if the natural vibration frequency of the rotating unit, which includes the crankshaft and the rotating motor shaft (generator rotating shaft), is the same as the engine vibration frequency, the rotating unit will resonate, causing the entire rotating unit to vibrate significantly.

[0027] In this embodiment, since a rubber damper 250 is sandwiched between the rotating shaft 210 and the rotor 240, the vibration of the dynamic damper formed by the rotor 240 and the rubber damper 250 can be used to suppress (counteract) the vibration (resonance) of the crankshaft 2 and the rotating shaft 210. As a result, vehicle body vibration can be suppressed, avoiding discomfort to the occupants.

[0028] In this embodiment, the component (rubber damper 250) used to suppress the vibration of the rotating unit is housed inside the generator 200, thus suppressing the resonance of the rotating unit without increasing the volume of the powertrain. Specifically, for example, resonance in the bending direction indicated by the arrow in FIG2 can be suppressed, as well as torsional resonance in the rotation direction.

[0029] In particular, based on the powertrain structure described in this embodiment, a range-extended electric vehicle with less vehicle body vibration can be realized. Specifically, since a range-extended electric vehicle is an electric vehicle equipped with a generator engine 100, the engine 100 will repeatedly start and stop when the battery charge is lower than a specified value. If the vibration frequency corresponding to the repeated rise and fall of the engine speed accompanying the start and stop of the engine 100 at a certain moment is consistent with the natural vibration frequency of the rotating unit, then the rotating unit will resonate, causing significant vehicle body vibration. In this embodiment, since a rubber damper 250 is sandwiched between the rotating shaft 210 and the rotor 240, the resonance of the rotating unit can be suppressed, thereby realizing a range-extended electric vehicle with less vehicle body vibration.

[0030] <Variation Example>

[0031] Next, a variation of this utility model will be described. In the above embodiment, the rotating shaft 210 is rotatably supported only by the radial bearing 223. That is, as a rotating body inside the generator 200, the support structure for the rotating shaft 210 and the rotor 240 adopts a cantilever support structure. In this variation, the support structure for the rotating shaft 210 and the rotor 240 adopts a two-end support structure. Other than this, the structure is the same as in the above embodiment. Therefore, only the support structure for the rotating shaft 210 will be described here.

[0032] Figure 3 is a cross-sectional view showing the internal structure of the generator 200 in this modified example. As shown in Figure 3, a cylindrical support pin 225 protrudes from the wall 224 on the side of the housing 220 away from the engine 100. A radial bearing 226 is mounted on the outer circumferential surface of the support pin 225.

[0033] Meanwhile, a connecting member 227 is installed on the end face of the rotor 240 on the side away from the engine 100. This connecting member 227 includes a first connecting portion 227a connected to the end face of the rotor 240, a second connecting portion 227b connected to the outer peripheral surface of the radial bearing 226, and a connecting portion 227c connecting the first connecting portion 227a and the second connecting portion 227b. The first connecting portion 227a, the second connecting portion 227b, and the connecting portion 227c can be arranged continuously or intermittently along the circumferential direction of the rotation shaft 210. Thus, the rotor 240 is rotatably supported on the housing 220 via the connecting member 227 and the radial bearing 226. That is, while the portion of the rotation shaft 210 near the engine 100 is rotatably supported by the radial bearing 223, the portion of the rotor 240 away from the engine 100 is rotatably supported by the radial bearing 226, thereby forming a two-end support structure.

[0034] This modified example can also achieve the same effect as the above-described embodiment, that is, the vibration (resonance) of the crankshaft 2 and the rotating shaft 210 can be suppressed (counteracted) by utilizing the vibration of the dynamic damper formed by the rotor 240 and the rubber damper 250.

[0035] Furthermore, in this modified example, by adopting a two-end support structure for the rotating shaft 210 and the rotor 240, it is possible to prevent the rotor 240 from undergoing large displacement inside the housing 220 (radial displacement caused by the elastic deformation of the rubber damper 250), thus reducing the air gap (the distance between the air gap and the stator 230) and keeping the performance of the generator 200 at a high level.

[0036] However, this invention is not limited to the above-described embodiments and modifications, and appropriate changes can be made as needed. For example, in the above embodiments and modifications, the rotor 240 and the rubber damper 250 were used together to act as a dynamic damper, but this invention is not limited to this. Alternatively, by elastically connecting the rotating shaft 210 and the rotor 240 with the rubber damper 250, the natural vibration frequency of the rotating unit composed of these components can be adjusted to suppress resonance of the rotating unit. That is, resonance of the rotating unit can be prevented by adjusting the natural vibration frequency of the rotating unit to a value outside the vibration frequency range of the engine 100.

Claims

1. A powertrain structure of an automobile, provided with a rotating unit including a crankshaft of an engine and a rotating shaft of a rotating electric machine, the crankshaft being directly connected to the rotating shaft, characterized by: an elastic member provided inside the rotating electric machine, the elastic member elastically connecting components constituting the rotating unit to each other.

2. The powertrain structure of an automobile according to claim 1, characterized by: the elastic member being a rubber damper, the rubber damper being disposed between the rotating shaft of the rotating electric machine and a rotor.

3. The powertrain structure of an automobile according to claim 1, characterized by: the automobile being a range-extended electric vehicle. ​ ​ ​

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