Driving unit for vehicle having structure reducing noise and vibration

Abstract

The present invention provides an electric driving unit for a vehicle, the electric driving unit comprising: a driving motor (100) for generating power; a first shaft (160) connected to the driving motor; a first gear (130) that is fitted onto the first shaft and rotates therewith; a second shaft (260) arranged parallel to the first shaft; a second gear (230) that is fitted onto the second shaft (260) and engages and rotates with the first gear (130); a sun gear (320) that rotates due to the rotational force of the second shaft (260); a planetary gear (330) disposed between the sun gear and a ring gear (310); and a wheel (430) that rotates by utilizing the rotational force of the planetary gear, wherein the first shaft (160) or the second shaft (260) has a structure that reduces noise and vibration.

Description

Vehicle driving unit adopting a structure that reduces noise and vibration

[0001] The present invention relates to a driving unit for a vehicle, and more specifically, to a driving unit for a vehicle that adopts a structure for reducing noise and vibration in a shaft connected to a drive motor.

[0002] Generally, a forklift is a type of special vehicle used to lift or transport cargo in various industrial sites. The basic configuration of such a forklift is that forks or carriages for lifting or unloading cargo are installed on the outside of the vehicle, and an engine or motor for driving the forklift is mounted inside the vehicle body.

[0003] In addition, an electric drive axle device is connected and installed to the engine or motor as a means for steering the forklift or controlling the wheels.

[0004] Accordingly, in conventionally widely used electric dual drive axles, power shafts input via motors are provided on both the left and right sides, and power generated by the motors is transmitted to each planetary gear unit.

[0005] Accordingly, the power transmitted to the planetary gear unit rotates the carrier shaft, and the carrier shaft is connected to a wheel adapter on which a wheel is mounted and rotated to control a series of forklift driving relationships.

[0006] However, the conventional power transmission method described above transmits power through gear combinations, and there is a problem in that vibration and noise are generated due to machining tolerances and assembly errors occurring between multiple gear combinations.

[0007] The present invention aims to solve the aforementioned problems by providing a vehicle driving unit that adopts a structure to reduce noise and vibration by compensating for play caused by machining and assembly errors while rotating, by adopting a noise reduction structure that keeps the shaft through which power is transmitted in a free state.

[0008] In addition, the purpose is to provide a vehicle driving unit that adopts a structure for reducing noise and vibration by compensating for the clearance caused by machining and assembly errors while rotating, by providing an automatic centering member that compensates for the clearance caused by machining and assembly errors between the bearing and the shaft.

[0009] However, the purpose of the present invention is not limited to the purposes mentioned above, and other unmentioned purposes will be clearly understood by those skilled in the art from the description below.

[0010] To achieve the above objective, the present invention provides a driving unit for an electric vehicle comprising a driving motor (100) that generates power, a first shaft (160) connected to the driving motor, a first gear (130) fitted onto the first shaft and rotating, a second shaft (260) arranged parallel to the first shaft, a second gear (230) fitted onto the second shaft (260) and meshing with the first gear (130) and rotating, a sun gear (320) that rotates by the rotational force of the second shaft (260), a planetary gear (330) disposed between the sun gear and the ring gear (310), and a wheel (430) that rotates by utilizing the rotational force of the planetary gear, wherein the driving unit for the vehicle adopts a structure that reduces noise and vibration on the first shaft (160) or the second shaft (260).

[0011] Additionally, regarding the first shaft (160), the left shaft end is called the 11th shaft end (161) and the right shaft end is called the 12th shaft end (163) based on the first gear (130), and regarding the second shaft (260), the left shaft end is called the 21st shaft end (261) and the right shaft end is called the 22nd shaft end (263) based on the second gear (230), and the structure is such that the 11th bearing (140) is fitted to the 11th shaft end (161) and the 12th bearing (150) is fitted to the 12th shaft end (163) to support the first shaft, and the 21st bearing (240) is fitted to the 21st shaft end (261) and the 22nd bearing (250) is fitted to the 22nd shaft end (263) to support the second shaft, and the drive motor is rotated to rotate the wheel (430). When in a normal state, the noise reduction structure is characterized by adopting a noise reduction structure that removes the 12th bearing of the 12th shaft end in the normal state to make the 12th shaft end of the 1st shaft free, thereby reducing noise and vibration by compensating for the play caused by machining and assembly errors while rotating as the 12th shaft end becomes free.

[0012] Meanwhile, regarding the first shaft (160), the left shaft end is called the 11th shaft end (161) and the right shaft end is called the 12th shaft end (163) based on the first gear (130); regarding the second shaft (260), the left shaft end is called the 21st shaft end (261) and the right shaft end is called the 22nd shaft end (263) based on the second gear (230); and the first shaft is supported by fitting the 11th bearing (140) to the 11th shaft end (161) and the 12th bearing (150) to the 12th shaft end (163), and the second shaft is supported by fitting the 21st bearing (240) to the 21st shaft end (261) and the 22nd bearing (250) to the 22nd shaft end (263), and the structure rotates the wheel (430) by turning the drive motor while supporting the second shaft. In a normal state, the noise reduction structure is characterized by reducing noise and vibration by compensating for play caused by machining and assembly errors while rotating, by providing an automatic alignment member (233) between the 21st bearing of the 21st shaft end and the 2nd shaft (260) in the normal state and additionally arranging the automatic alignment member (233) in such a way that noise and vibration are reduced.

[0013] Additionally, a through hole (237) is formed in the center of the above-mentioned self-aligning member (233), and a first spline (235) is formed on the inner surface of the through hole, and a second spline (265) that meshes with the first spline is formed on a part of the outer surface of the second shaft so that the second shaft is fitted into and coupled with the first spline (235).

[0014] The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

[0015] Prior to this, terms and words used in this specification and claims should not be interpreted in their ordinary and dictionary senses, but should be interpreted in a sense and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0016] As described above, according to the present invention, by adopting a noise reduction structure that keeps the shaft through which power is transmitted in a free state, noise and vibration can be reduced by compensating for the play caused by machining and assembly errors while rotating.

[0017] In addition, by providing an automatic centering member that compensates for the clearance caused by machining and assembly errors between the bearing and the shaft, noise and vibration can be reduced by compensating for the clearance while rotating to compensate for the clearance caused by machining and assembly errors.

[0018] FIG. 1 is a schematic diagram illustrating the structure of a conventional electric vehicle drive unit.

[0019] FIG. 2 is a schematic diagram illustrating the structure of a drive unit for an electric vehicle having a noise reduction structure according to a preferred first embodiment of the present invention.

[0020] FIG. 3 is a schematic diagram illustrating the structure of a drive unit for an electric vehicle having a noise reduction structure according to a preferred second embodiment of the present invention.

[0021] [Correction pursuant to Rule 91 02.06.2025] FIG. 4 is a schematic diagram illustrating the structure of an automatic centering member according to a preferred second embodiment of the present invention. FIG. 5 is a graph showing the amount of noise measured compared to conventional equipment when a noise reduction structure according to an embodiment of the present invention is applied, and experimental equipment to which the noise reduction structure is applied.

[0022] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation.

[0023] Furthermore, the terms described below are defined in consideration of their functions within the present invention, and these may vary depending on the intent or practice of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0024] In addition, the following embodiments are not intended to limit the scope of the present invention but are merely exemplary details of the components presented in the claims of the present invention, and embodiments including components that are included in the technical concept throughout the specification of the present invention and are substitutable as equivalents for the components of the claims may be included in the scope of the present invention.

[0025] Figure 1 attached is a schematic diagram illustrating the structure of a conventional drive unit for an electric vehicle, Figure 2 is a schematic diagram illustrating the structure of a drive unit for an electric vehicle having a noise reduction structure according to a preferred first embodiment of the present invention, Figure 3 is a schematic diagram illustrating the structure of a drive unit for an electric vehicle having a noise reduction structure according to a preferred second embodiment of the present invention, and Figure 4 is a schematic diagram illustrating the structure of an automatic centering member according to a preferred second embodiment of the present invention.

[0026]

[0027] Referring to FIG. 1, an electric vehicle drive unit comprises a drive motor (100) that generates power, a first shaft (160) connected to the drive motor, a first gear (130) fitted onto the first shaft and rotating, a second shaft (260) arranged parallel to the first shaft, a second gear (230) fitted onto the second shaft (260) and meshing with the first gear (130) and rotating, a sun gear (320) that rotates by the rotational force of the second shaft (260), a planetary gear (330) arranged between the sun gear and the ring gear (310), and a wheel (430) that rotates by utilizing the rotational force of the planetary gear. A vehicle driving unit adopting a structure for reducing noise and vibration according to the present invention adopts and applies a structure for reducing noise and vibration to the first shaft (160) or the second shaft (260). It is characterized by the fact that.

[0028] Referring to FIG. 2, the left shaft end of the first shaft (160) is called the 11th shaft end (161) and the right shaft end is called the 12th shaft end (163) based on the first gear (130), and the left shaft end of the second shaft (260) is called the 21st shaft end (261) and the right shaft end is called the 22nd shaft end (263) based on the second gear (230), and the 11th bearing (140) is fitted to the 11th shaft end (161) and the 12th bearing (150) is fitted to the 12th shaft end (163) to support the first shaft.

[0029] And when the structure in which the 21st bearing (240) is fitted to the 21st shaft end (261) and the 22nd bearing (250) is fitted to the 22nd shaft end (263) to support the 2nd shaft, and the drive motor is rotated to rotate the wheel (430), is referred to as the normal state,

[0030] The noise reduction structure is characterized by adopting a noise reduction structure that removes the 12th bearing (150) of the 12th shaft section (163) in the normal state to make the 12th shaft section (163) of the 1st shaft (160) free, thereby reducing noise and vibration by compensating for the play caused by machining and assembly errors while rotating as the 12th shaft section becomes free.

[0031] That is, as the 12th shaft section becomes free, a structure is provided that can reduce noise and vibration caused by assembly errors during rotation due to the 12th shaft section becoming free and self-adjusting.

[0032] In addition, when the restraining force of the 11th bearing (140) restraining the 11th shaft end (161) in the above normal state is set to '5' and the restraining force of the 12th bearing (150) restraining the 12th shaft end (163) is set to '5', it is preferable to adopt the 11th bearing (140) such that in the above noise reduction structure, the restraining force of the 12th shaft end becomes '0' and the restraining force of the 11th shaft end becomes 5 to 10.

[0033]

[0034] Meanwhile, referring to FIG. 3, the left shaft end of the first shaft (160) is called the 11th shaft end (161) and the right shaft end is called the 12th shaft end (163) based on the first gear (130), and the left shaft end of the second shaft (260) is called the 21st shaft end (261) and the right shaft end is called the 22nd shaft end (263) based on the second gear (230), and the 11th bearing (140) is fitted to the 11th shaft end (161) and the 12th bearing (150) is fitted to the 12th shaft end (163) to support the first shaft.

[0035] And when the structure in which the 21st bearing (240) is fitted to the 21st shaft end (261) and the 22nd bearing (250) is fitted to the 22nd shaft end (263) to support the 2nd shaft, and the drive motor is rotated to rotate the wheel (430), is referred to as the normal state,

[0036] The above noise reduction structure is characterized by reducing noise and vibration by compensating for play caused by machining and assembly errors while rotating, by providing an automatic alignment member (233) between the 21st bearing (240) of the 21st shaft end (261) and the 2nd shaft (260) in the above normal state and additionally arranging the automatic alignment member (233).

[0037]

[0038]

[0039] Additionally, referring to FIGS. 3 and 4, a through hole (237) is formed in the center of the self-aligning member (233), and a first spline (235) is formed on the inner surface of the through hole.

[0040] And, in order for the second shaft (260) to be fitted and coupled to the first spline (235), a second spline (265) that meshes with the first spline is formed on a part of the outer surface of the second shaft.

[0041] Additionally, since the first spline (235) and the second gear (230) are formed as a single unit, the assembly tolerance between the second gear and the second shaft (260) is the assembly tolerance between the first spline and the second spline (265).

[0042] In addition, the assembly tolerance is preferably assembled to allow for a loose fit, and the first spline (235) and the second spline (265) are manufactured and assembled to have a gap of 0.1 mm to 0.3 mm during assembly.

[0043] By intentionally providing such assembly tolerances to result in a loose fit, the first spline (235) and the second spline (265) are assembled with loose fit assembly tolerances. Consequently, the loosely fitted first spline (235) and the second spline (265) self-adjust to reduce vibration and noise caused by assembly errors during rotation when the entire assembly is combined.

[0044] In addition, when the restraining force of the 21st bearing (240) restraining the 21st shaft end (261) in the above normal state is set to '5' and the restraining force of the 22nd bearing (250) restraining the 22nd shaft end (263) is set to '5', when the self-aligning member (233) is adopted, it is preferable that the 21st bearing (240) supports the outer surface of the self-aligning member (233) and restrains the restraining force to be 5 to 10.

[0045] Additionally, the self-aligning member (233) is provided between the outer diameter where the 21st bearing (240) is assembled near the 21st shaft end (261) and the inner diameter of the 21st bearing (240), and the assembly tolerance between the outer diameter where the 21st bearing (240) is assembled at the 21st shaft end (261) and the inner diameter of the 21st bearing (240) is manufactured to have a gap of 0.1 to 0.3 mm, which is a loose fit during assembly.

[0046] Accordingly, the assembly is characterized by being assembled in such a way that the noise and vibration generated during rotation due to the initial assembly error during the entire assembly are dampened as the outer diameter of the 21st bearing (240) of the loosely fitted 21st shaft section (261) and the inner diameter of the 21st bearing (240) self-adjust.

[0047] In addition, since the first spline (235) and the second gear (230) are formed integrally in the present invention, the assembly tolerance between the second gear and the second shaft is the assembly tolerance between the first spline and the second spline (265).

[0048] In addition, in the present invention, when the restraining force of the 21st bearing (240) restraining the 21st shaft end (261) in the normal state is set to '5' and the restraining force of the 22nd bearing (250) restraining the 22nd shaft end (263) is set to '5', when the self-aligning member (233) is adopted, the 21st bearing (240) supports the outer surface of the self-aligning member (233) and restrains the restraining force to be 5 to 10.

[0049] The above assembly tolerance is such that the assembly is performed to a loose fit, and it is preferable that the first spline and the second spline (265) are manufactured and assembled to have a gap of 0.1 to 0.3 mm during assembly.

[0050]

[0051] [Correction pursuant to Rule 91 02.06.2025]

[0052] [Correction pursuant to Rule 91 02.06.2025]

[0053]

[0054]

[0055] [Correction pursuant to Rule 91 02.06.2025]

[0056] [Correction pursuant to Rule 91 02.06.2025]

[0057]

[0058] [Correction pursuant to Rule 91 02.06.2025] FIG. 5 is a graph showing the amount of noise measured compared to conventional equipment when a noise reduction structure according to an embodiment of the present invention is applied, and experimental equipment to which the noise reduction structure is applied.

[0059] [Correction pursuant to Rule 91 02.06.2025] The graph in Fig. 5 has rotational speed (RPM) on the horizontal axis and noise level (dBA) on the vertical axis. As shown in the graph in Fig. 5, it can be confirmed that the driving unit with the noise reduction structure of the present invention generates less noise level (dBA) per RPM compared to the driving unit of the prior art.

[0060] Although the present invention has been described in detail through specific embodiments, this is for the purpose of specifically explaining the invention, and the invention is not limited thereto. It is evident that modifications or improvements can be made by those skilled in the art within the technical scope of the present invention.

[0061] All simple variations or modifications of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be clarified by the appended claims.

[0062] [Explanation of the symbol]

[0063] 100 : Drive motor 130 : 1st gear

[0064] 140 : 11th bearing 150 : 12th bearing

[0065] 160: 1st axis 161: 11th axis section

[0066] 163 : 12th shaft section 230 : 2nd gear

[0067] 233 : Self-aligning member 235 : First spline

[0068] 237 : Through hole 240 : 21st bearing

[0069] 250 : 22nd bearing 260 : 2nd shaft

[0070] 261 : 21st shaft section 263 : 22nd shaft section

[0071] 265 : 2nd spline 310 : Ring gear

[0072] 320 : Sun gear 330 : Planetary gear

[0073] 430 : Wheel

Claims

1. An electric vehicle drive unit comprising a drive motor (100) that generates power, a first shaft (160) connected to the drive motor, a first gear (130) fitted onto the first shaft and rotating, a second shaft (260) arranged parallel to the first shaft, a second gear (230) fitted onto the second shaft (260) and meshing with the first gear (130) and rotating, a sun gear (320) that rotates by the rotational force of the second shaft (260), a planetary gear (330) arranged between the sun gear and the ring gear (310), and a wheel (430) that rotates by utilizing the rotational force of the planetary gear. A vehicle driving unit having a structure that reduces noise and vibration on the first axis (160) or second axis (260).

2. In Paragraph 1, In the first shaft (160) above, the left shaft section is called the 11th shaft section (161) based on the first gear (130), and the right shaft section is called the 12th shaft section (163). In the above second shaft (260), the left shaft section is called the 21st shaft section (261) and the right shaft section is called the 22nd shaft section (263) based on the above second gear (230). A first bearing (140) is fitted onto the first shaft section (161) and a second bearing (150) is fitted onto the second shaft section (163) to support the first shaft, and When the structure in which the 21st bearing (240) is fitted to the 21st shaft end (261) and the 22nd bearing (250) is fitted to the 22nd shaft end (263) to support the 2nd shaft, and the drive motor is rotated to rotate the wheel (430), is referred to as the normal state, A driving unit for a vehicle having a structure for reducing noise and vibration on the first or second shaft, characterized in that the noise reduction structure adopts a noise reduction structure that removes the 12th bearing of the 12th shaft end in the normal state to make the 12th shaft end of the first shaft free, thereby reducing noise and vibration by compensating for the play caused by machining and assembly errors while rotating as the 12th shaft end becomes free.

3. In Paragraph 2, When the restraining force of the 11th bearing (140) restraining the 11th shaft end (161) in the above normal state is set to '5', and the restraining force of the 12th bearing (150) restraining the 12th shaft end (163) is set to '5', A vehicle driving unit having a structure for reducing noise and vibration in the first or second shaft, characterized in that the restraining force of the 12th shaft end in the noise reduction structure is '0' and the restraining force of the 11th shaft end is 5 to 10 by adopting a 11th bearing (140).

4. In Paragraph 1, In the first shaft (160), the left shaft end is called the 11th shaft end (161) and the right shaft end is called the 12th shaft end (163) based on the first gear (130). In the above second shaft (260), the left shaft end is called the 21st shaft end (261) and the right shaft end is called the 22nd shaft end (263) based on the above second gear (230). A first bearing (140) is fitted onto the first shaft section (161) and a second bearing (150) is fitted onto the second shaft section (163) to support the first shaft, and When the structure in which the 21st bearing (240) is fitted to the 21st shaft end (261) and the 22nd bearing (250) is fitted to the 22nd shaft end (263) to support the 2nd shaft, and the drive motor is rotated to rotate the wheel (430), is referred to as the normal state, A vehicle driving unit having adopted a structure for reducing noise and vibration on the first or second shaft, characterized in that the noise reduction structure is provided with an automatic alignment member (233) between the second bearing of the second shaft end and the second shaft (260) in the normal state, and the automatic alignment member (233) is additionally arranged to compensate for the clearance caused by machining and assembly errors while rotating, thereby reducing noise and vibration.

5. In Paragraph 4, The above automatic centering member (233) is A vehicle driving unit having a structure for reducing noise and vibration in the first shaft or second shaft, characterized by being provided between the outer diameter where the second bearing (240) is assembled near the second shaft end (261) and the inner diameter of the second bearing (240).

6. In Paragraph 5, A vehicle driving unit adopting a structure for reducing noise and vibration in the first shaft or second shaft, characterized in that the assembly tolerance between the outer diameter of the second bearing (240) of the second shaft section (261) and the inner diameter of the second bearing (240) is manufactured to have a gap of 0.1 to 0.3 mm, which is a loose fit during assembly, so that vibration or noise generated during rotation due to the assembly tolerance created during the entire assembly is reduced as the loose fit between the outer diameter of the second bearing (240) of the second shaft section (261) and the inner diameter of the second bearing (240) self-adjusts.

7. In Paragraph 4, A vehicle driving unit having a structure for reducing noise and vibration in the first or second shaft, characterized in that a through hole (237) is formed in the center of the above-mentioned self-aligning member (233), a first spline (235) is formed on the inner surface of the through hole, and a second spline (265) that meshes with the first spline is formed on a part of the outer surface of the second shaft so that the second shaft is fitted into and coupled with the first spline (235).

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