Clutch driving apparatus for automatic shift control and two-speed transmission apparatus including the same for light vehicles

Abstract

The present invention relates to a clutch drive device for automatic transmission control. The drive device comprises: an input shaft cam flange having an input shaft on one surface; a plurality of swash plates protruding from the other surface of the input shaft cam flange, arranged along the circumferential direction, and having inclined inner surfaces; an output shaft cam flange coupled to the input shaft cam flange to receive driving force and having a plurality of coupling grooves on a surface opposite to the input shaft cam flange—the coupling grooves are formed in a shape corresponding to the inner surface of the swash plate—; and a ball-shaped cam roller disposed to be movable within a fluid space formed between the inclined inner surface of the swash plate and the coupling grooves, wherein the cam roller moves outward along the inclined inner surface of the swash plate by centrifugal force as the rotational speed of the input shaft increases, thereby pressurizing a rear clutch drive unit to engage the clutch.

Description

Technology Field

[0001] The present invention relates to a clutch drive device for automatic transmission control equipped with a loading cam that changes position according to the speed of the vehicle, and a two-speed transmission device for a small electric vehicle including the same. Background Technology

[0002] Generally, electric vehicles refer to eco-friendly vehicles that emit no exhaust gases whatsoever, as they use electricity as a power source, unlike gasoline or diesel vehicles. Recently, many advanced automakers around the world, including those in China, have been making significant efforts to develop such electric vehicles.

[0003] These electric vehicles consist of high-voltage batteries as their power source and use rechargeable and high-capacity secondary batteries such as nickel-cadmium, nickel-hydrogen, and lithium-ion batteries.

[0004] Since the drive motor, which serves as the power source for the electric vehicle, is driven by rotation using the electrical energy from the aforementioned high-voltage battery, the rotational force and speed of the drive motor can be directly controlled through the vehicle control unit, thereby enabling the vehicle speed to be shifted accordingly. In other words, unlike internal combustion engine vehicles, electric vehicles allow for easy control of the drive motor; therefore, the vehicle speed can be smoothly shifted through the control of the drive motor without the need for a separate transmission.

[0005] Meanwhile, when vehicle speed is controlled by controlling the drive motor, the drive motor is subjected to a heavy load, which increases electrical energy consumption and consequently shortens the driving range per charge. Additionally, there were problems such as the configuration of the control unit and the drive motor for controlling the drive motor becoming complex and the capacity increasing.

[0006] As vehicle speed increases, the speed of the drive motor must also increase accordingly; high torque is required at low speeds and low torque is required at high speeds, so electric vehicles require transmissions suitable for energy efficiency. However, research and development for transmissions for electric vehicles currently involves modifying and using automatic or manual transmissions from existing gasoline or diesel vehicles.

[0007] These automatic or manual transmissions have the disadvantage of being large in size or having complex shifting, as they use a relatively bulky hydraulic wet multi-plate clutch or a synchronizer that is prone to wear and noise. Prior art literature

[0008] Korean Patent Publication No. 10-1282691 (Published July 5, 2013) The problem to be solved

[0009] The objective of the present invention is to provide a clutch drive device for automatic transmission control equipped with a loading cam that changes position according to the speed of the vehicle, and a two-speed transmission device for a small electric vehicle including the same. means of solving the problem

[0010] The present invention, for solving the above problems, relates to a clutch drive device for automatic transmission control. The drive device comprises: an input shaft cam flange having an input shaft on one surface; a plurality of swash plates protruding from the other surface of the input shaft cam flange, arranged along the circumferential direction, and having inclined inner surfaces; an output shaft cam flange coupled to the input shaft cam flange to receive driving force and having a plurality of coupling grooves on a surface opposite to the input shaft cam flange—the coupling grooves are formed in a shape corresponding to the inner surface of the swash plate—; and a ball-shaped cam roller disposed to be movable within a fluid space formed between the inclined inner surface of the swash plate and the coupling grooves, wherein as the rotational speed of the input shaft increases, the cam roller moves outward along the inclined inner surface of the swash plate by centrifugal force, thereby pressurizing a rear clutch drive unit to engage the clutch.

[0011] According to an embodiment of the present invention, the swash plate is formed to be tapered toward the output shaft cam flange by the inclined inner surface, and the coupling groove is formed to be tapered toward the same side as the inclined inner surface of the swash plate, and the difference between the tapered slope of the coupling groove and the tapered slope of the inner surface of the swash plate increases as it approaches the output shaft cam flange, so that the width of the flow space may decrease as it approaches the output shaft cam flange.

[0012] According to an embodiment of the present invention, the width of the movable space in which the cam roller can move is equal to or greater than the diameter of the cam roller at the initial position of the cam roller, and may be smaller than the diameter of the cam roller on the path toward the output shaft cam flange.

[0013] According to an embodiment of the present invention, the output shaft cam flange is formed to be spaced to the right, away from the input shaft cam flange, by the outward movement of the cam roller, and the clutch drive unit is coupled to the side of the output shaft cam flange. When the rotational speed of the input shaft rises above a threshold value, a first mode is set in which the clutch drive unit is pressurized by the rightward movement of the output shaft cam flange to engage the clutch, and when the rotational speed of the input shaft falls below a threshold value, a second mode is set in which the pressure on the clutch drive unit is released by the leftward movement of the output shaft cam flange to release the clutch.

[0014] According to an embodiment of the present invention, a two-stage transmission for a small electric vehicle comprising a clutch drive unit for automatic transmission control comprises: a clutch operated by the clutch drive unit; and a two-stage transmission connected to the clutch and comprising a planetary gear, wherein in the first mode, the clutch is engaged to perform an upper gear shift of the two-stage transmission, and in the second mode, the clutch is disengaged to perform a lower gear shift of the two-stage transmission. Effects of the invention

[0015] According to the present invention, a two-stage gear shift can be automatically implemented through a loading cam that changes position according to the speed of the vehicle, and since the loading cam for applying an axial load implements the gear shift without a separate actuator when it reaches a certain rotational speed, gear shift control is not required and the gear shift dissonance is minimal.

[0016] In addition, since the device itself does not use hydraulic devices such as clutches and torque converters used in conventional internal combustion engine vehicle transmissions, a simple structural design consisting of a combination of a motor, compound planetary gears, and a transmission mechanism (loading cam) is possible, enabling miniaturization and weight reduction. Brief explanation of the drawing

[0017] FIG. 1 (a) and (b) are a perspective view and a side cross-sectional view illustrating the structure of a clutch drive device for automatic transmission control according to the present invention, and the cam flange and cam roller (ball) of the loading cam therein. FIG. 2 is a perspective view of the apparatus of FIG. 1 viewed from another side. Figures 3 (a) and 3 (b) are side views of the position change according to the axial load of the output shaft cam flange of a two-speed transmission for a small electric vehicle including the clutch drive unit of Figure 1. Specific details for implementing the invention

[0018] Hereinafter, specific details for implementing the present invention will be described with reference to the attached drawings. Furthermore, in describing the present invention, detailed descriptions of related known functions are omitted if they are deemed obvious to a person skilled in the art and could unnecessarily obscure the essence of the invention.

[0020] FIGS. 1 (a) and (b) are a perspective view and a side cross-sectional view illustrating a clutch drive device for automatic transmission control according to the present invention, and the structure of the cam flange and cam roller (ball) of the loading cam therein. FIG. 2 is a perspective view of the device of FIG. 1 viewed from another side.

[0021] Referring to FIG. 1 (a), (b) and FIG. 2, a clutch drive device for automatic transmission control according to the present invention has a loading cam comprising an input shaft cam flange (10), a swash plate (20), an output shaft cam flange (30), and a cam roller (40). The input shaft cam flange (10) has an input shaft (11) on one side.

[0022] The above clutch drive unit is configured as part of a two-speed transmission for a small electric vehicle. In the above two-speed transmission, the input from the power source is transmitted to the two-speed transmission (60) via the input shaft (11), the input shaft cam flange (10), the output shaft cam flange (30), the output shaft (31), and the clutch (50). The clutch (50) is operated by a clutch drive unit (51) connected to one side. The two-speed transmission (60) includes a planetary gear, so that gear shifting is possible according to the engagement / disengagement of the clutch (50).

[0023] The swash plate (20) protrudes circumferentially from the other side of the input shaft cam flange (10) and has an inclined inner surface (21) arranged along the circumferential direction. The inner surface (21) of the swash plate (20) is formed in a shape that slopes outward from the central axis as it moves away from the other side of the input shaft cam flange (10). That is, the swash plate (20) is formed to taper toward the output shaft cam flange (30) by the inclined inner surface (21).

[0024] The output shaft cam flange (30) is coupled with the input shaft cam flange (10) to receive driving force. The output shaft cam flange (30) has a plurality of coupling grooves (31). The coupling grooves (31) are formed in a shape corresponding to the inner surface (21) of the slant plate (20) so as to be coupled with a plurality of slant plates (20) on the opposite surface facing the input shaft cam flange (10). The coupling grooves (31) are formed to taper toward the same side as the inclined inner surface (21) of the slant plate (20). The difference between the tapered slope of the coupling grooves (31) and the tapered slope of the inner surface of the slant plate (20) increases as it approaches the output shaft cam flange (30), and the width of the flow space (s) decreases as it approaches the output shaft cam flange (30).

[0025] The cam roller (40) is movably positioned within a fluid space (s) formed between the inclined inner surface (21) of the swash plate (20) and the coupling groove (31), and is formed in a ball shape. As the rotational speed of the input shaft (11) increases, the cam roller (40) moves outward along the inclined inner surface (21) of the swash plate (20) by centrifugal force. Specifically, as the rotational speed of the input shaft (11) increases, the cam roller (40) moves radially due to centrifugal force, and the input shaft cam flange (10) applies force in the axial direction due to the angle of the inclined inner surface (21) of the swash plate (20).

[0026] Since the cam roller (40) transmits rotational force from the input shaft (11) and also transmits force in the axial direction, a trajectory capable of moving the cam roller (40) must be created in the cam flange (10). By changing the curvature of this trajectory, the axial movement of the cam roller (40) can be controlled, and the transmission quality can be adjusted by changing the vertical force required for clutch engagement.

[0027] The width of the movable space(s) in which the cam roller (40) can move is equal to or greater than the diameter of the cam roller (40) at the initial position of the cam roller (40), and becomes smaller than the diameter of the cam roller (40) on the path toward the output shaft cam flange (30). Therefore, on the path of movement of the cam roller (40), the diameter of the cam roller (40) becomes larger than the width of the movable space(s), thereby pressing the output shaft cam flange (30).

[0028] Figures 3 (a) and 3 (b) are side views of the position change according to the axial load of the output shaft cam flange of a two-speed transmission for a small electric vehicle including the clutch drive unit of Figure 1.

[0029] Referring to FIG. 3 (a) and (b), the output shaft cam flange (30) is formed to be spaced to the right, away from the input shaft cam flange (10), by the outward movement of the cam roller (40). A clutch drive unit (51) is coupled to the right side of the output shaft cam flange (30). Accordingly, the output shaft cam flange (30) presses the clutch drive unit (51) to engage the clutch (50).

[0030] That is, when the speed of the input shaft cam flange (10) increases, the axial displacement of the cam roller (40) increases, and accordingly, the output shaft cam flange (30) applies an axial load, thereby enabling the clutch (50) on the driving side to engage. By moving the clutch driving unit (51) axially, an axial load is applied to the release bearing connected to the clutch plate in the case of a dry single-plate clutch, or to the clutch piston in the case of a wet multi-plate clutch, thereby enabling the engagement and disengagement of the clutch.

[0031] When the rotational speed of the input shaft (11) rises above a threshold value, a first mode is established in which the clutch drive unit (51) is pressurized by moving the output shaft cam flange (30) to the right and the clutch (50) is engaged. When the rotational speed of the input shaft (11) falls below a threshold value, a second mode is established in which the clutch drive unit (51) is released by moving the output shaft cam flange (30) to the left and the clutch (50) is released.

[0032] In the first mode, the clutch (50) is engaged to achieve the upper gear (2nd gear) of the 2-speed transmission, and in the second mode, the clutch (50) is disengaged to achieve the lower gear (1st gear) of the 2-speed transmission. According to the present invention, the position of the cam roller (40) changes according to the speed of the vehicle, so that the clutch (50) is engaged / disengaged, and thus automatic gear shifting is achieved.

[0033] Therefore, automatic 2-speed shifting can be achieved through a loading cam that changes position according to the vehicle speed, and since the loading cam for applying axial load implements shifting without a separate actuator when it reaches a certain rotational speed, shifting control is not required and shifting feel is minimal. In addition, the device itself does not use hydraulic devices such as clutches and torque converters used in conventional internal combustion engine vehicle transmissions, and a simple structural design consisting of a combination of a motor, a compound planetary gear, and a transmission mechanism (loading cam) is possible, allowing for a compact and lightweight design.

[0035] The scope of protection in this field is not limited to the description and expression of the embodiments explicitly described above. Furthermore, it is added once again that the scope of protection of the present invention cannot be limited by obvious changes or substitutions in the technical field to which the present invention belongs.

Claims

Claim 1 An input shaft cam flange having an input shaft on one side; a plurality of swash plates protruding from the other side of the input shaft cam flange, arranged along the circumferential direction, and having inclined inner surfaces; an output shaft cam flange coupled to the input shaft cam flange to receive driving force, and having a plurality of coupling grooves on an opposing surface facing the input shaft cam flange—the coupling grooves are formed in a shape corresponding to the inner surface of the swash plates—; A clutch drive device for automatic transmission control, comprising a ball-shaped cam roller movably disposed within a fluid space formed between the inclined inner surface of the swash plate and the coupling groove, wherein the cam roller moves outward along the inclined inner surface of the swash plate by centrifugal force as the rotational speed of the input shaft increases, thereby pressurizing a rear clutch drive unit to engage the clutch, wherein the swash plate is formed to be tapered toward the output shaft cam flange by the inclined inner surface, and the coupling groove is formed to be tapered toward the same side as the inclined inner surface of the swash plate, and the difference between the tapered slope of the coupling groove and the tapered slope of the inner surface of the swash plate increases toward the output shaft cam flange, and the width of the fluid space decreases toward the output shaft cam flange. Claim 2 delete Claim 3 A clutch drive device for automatic transmission control according to claim 1, characterized in that the width of the movable space in which the cam roller can move is equal to or greater than the diameter of the cam roller at the initial position of the cam roller, and becomes smaller than the diameter of the cam roller on the path toward the output shaft cam flange. Claim 4 A clutch drive device for automatic transmission control, characterized in that, in paragraph 3, the output shaft cam flange is formed to be spaced to the right away from the input shaft cam flange by the outward movement of the cam roller, the clutch drive unit is coupled to the side of the output shaft cam flange, and when the rotational speed of the input shaft rises above a threshold value, a first mode is set in which the clutch drive unit is pressurized by the rightward movement of the output shaft cam flange and the clutch is engaged, and when the rotational speed of the input shaft falls below a threshold value, a second mode is set in which the pressure on the clutch drive unit is released by the leftward movement of the output shaft cam flange and the clutch is released. Claim 5 A two-speed transmission for a small electric vehicle comprising a clutch drive unit for automatic transmission control according to claim 4, the two-speed transmission comprising: a clutch operated by the clutch drive unit; and a two-speed transmission connected to the clutch and including a planetary gear, wherein in the first mode, the clutch is engaged to perform an upper gear shift of the two-speed transmission, and in the second mode, the clutch is disengaged to perform a lower gear shift of the two-speed transmission.

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