KR101172122B1 - Variable Gear Ratio Epicyclic Gear Apparatus - Google Patents

Abstract

The present invention relates to a variable gear ratio planetary gear device.

The present invention provides a variable gear ratio planetary gear device, comprising: a first planetary gear device including a first sun gear, a first planetary gear external to the first sun gear, and a first ring gear inscribed with the first planetary gear; A second planetary gear device including a second sun gear, a second planetary gear external to the second sun gear, and a second ring gear inscribed with the second planetary gear; A shared carrier disposed between the first planetary gear device and the second planetary gear device and supporting the first planetary gear and the second planetary gear, respectively; A rotational force assistance device for selectively transmitting rotational force to the first ring gear or the second ring gear; And a housing that surrounds the first planetary gear device, the second planetary gear device, and the shared carrier.

According to the present invention, unlike the conventional variable gear ratio planetary gear device having a carrier as a first input, a sun gear as a second input, and a ring gear as an output, the first sun gear and the second sun gear have a first input and an output, respectively. Unlike the conventional input shaft penetrating the sun gear, the input shaft does not have to penetrate the first sun gear, thereby reducing the radial size of the planetary gear device and improving the assemblability.

Planetary gear device, sun gear, planetary gear, shared carrier, ring gear, housing

Description

Variable Gear Ratio Epicyclic Gear Apparatus}

1 is a block diagram of an active front wheel steering apparatus for a vehicle according to the prior art;

2A is a schematic diagram showing a gear ratio conversion device;

2b is a perspective view of a helical gear; And

3 is a schematic cross-sectional view of a variable gear ratio planetary gear device according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

101: steering wheel 103: steering shaft

105: steering column 107: input angle sensor

109: gear ratio variable device 111: first motor

117: vehicle speed sensor 119: rack bar

121: rack-pinion mechanism part 123: second motor

125: electronic control unit

201: carrier 203: planetary gear

205: internal gear 209: worm shaft

211: worm wheel 213: sun gear

215: input shaft 217: output shaft

The present invention relates to a variable gear ratio planetary gear device. More specifically, unlike the conventional variable gear ratio planetary gear device having a carrier as a first input, a sun gear as a second input, and a ring gear as an output, the first sun gear and the second sun gear are responsible for the first input and the output, respectively. Unlike the conventional input shaft penetrates the sun gear, in the present invention, the input shaft does not have to penetrate the first sun gear, thereby reducing the radial size of the planetary gear device and improving the assemblability of the planetary gear device. It is about.

The steering device of the vehicle is a device for changing the driving direction of the vehicle at the driver's will, and is a device for assisting the driver in driving the vehicle in a desired direction by arbitrarily changing the rotation center of the front wheel.

In addition, the Power Steering Apparatus assists the driver's steering wheel operation by using a device that provides steering assistance power when the driver operates the steering wheel. It is a device to change the direction of the car.

Such power assisted steering devices are largely classified into hydraulic power assisted steering (HPS) and electric power assisted steering (EPS).

The hydraulic power assisted steering system is provided when the hydraulic pump connected to the rotating shaft of the engine supplies the hydraulic fluid to the working cylinder, and the hydraulic assist hydraulic power of the hydraulic oil is provided to allow the rack bar to move in the horizontal direction, thereby driving both wheels. Is a device that allows the driver to steer with little force.

On the other hand, the electric power assist steering device includes a motor and an electronic control unit (ECU) in a rack bar or column instead of a hydraulic pump and a working cylinder, so that the steering assist power is driven by the driving of the motor. This is the device that is fed.

Recently, the steering shaft is separated from the steering wheel and the steering column to actively cope with the external environment such as a strong wind blowing while driving or a road surface that is not symmetrical to the left and right. Active front wheel steering that adjusts the steering angle by continuously detecting the steering angle that changes from time to time without transmitting it directly to the steering column, comparing it with various information of the vehicle, and transmitting it as an electrical signal to the motor that controls the rotation of the steering column of the steering column. Device (AFS: Active Front Wheel Steering) has emerged. In addition, such an active front wheel steering apparatus is provided with a gear ratio converting apparatus for converting a gear ratio between an input and an output in the gear apparatus.

1 is a configuration diagram of an active front wheel steering apparatus for a vehicle according to the prior art, and FIG. 2A is a schematic diagram illustrating a gear ratio conversion apparatus.

As shown in FIG. 1 and FIG. 2A, the active front wheel steering apparatus for a vehicle according to the prior art includes a steering wheel 101, a steering shaft 103 connected to the steering wheel 101, and a steering shaft 103. FIG. The steering column 105 surrounding, the input angle sensor 107 formed at the lower end of the steering column 105, the gear ratio converting apparatus 109 formed below the input angle sensor 107, and the gear ratio converting apparatus 109 The first motor 111 for driving, the first motor position sensor 113 provided in the first motor 111, the output angle sensor 115 formed on the lower side of the gear ratio converter 109, the speed of the vehicle The rack-pinion mechanism part 121 and the rack bar which are formed under the vehicle speed sensor 117 and the gear ratio converter 109 for sensing, and convert the rotational movement of the steering shaft 103 into the linear motion of the rack bar 119. From the second motor 123, the input angle sensor 107, the first motor position sensor 113 and the output angle sensor 115 to supply steering assistance power to the 119. It is configured to include an ECU (125) receiving various signals.

The operating principle of the active front wheel steering apparatus for a vehicle according to the prior art having such a configuration is as follows.

As the driver manipulates the steering wheel 101, when the input shaft 215 rotates, the carrier 201 formed at the lower end of the input shaft 215 rotates in association with the input shaft 215.

In this case, the planetary gear 203 rotatably supported by the carrier 201 rotates, and the ring gear 205 in contact with the planetary gear 203 is rotated by the rotation of the planetary gear 203. It is rotated by receiving.

Finally, the output shaft 217 formed at the lower end of the ring gear 205 is rotated so that the steering force generated by the driver's steering wheel 101 operation is transmitted to the rack-pinion mechanism part 121.

However, the above process is a case where the first motor 111 does not operate, and when the first motor 111 operates, the following changes occur.

Electrical signals are generated from the vehicle speed sensor 117 for detecting the speed of the vehicle, the input angle sensor 107 and the output angle sensor 115 for detecting a change in the steering angle, and the first motor position sensor 113, respectively. When 125 is reached, the ECU 125 drives the first motor 111 by transmitting an electrical signal to the first motor 111.

In addition, as the first motor 111 is driven by the above process, the worm wheel 209, which is connected to the motor shaft (not shown), also rotates and is engaged with the worm shaft 209 accordingly. 211 rotates, and the sun gear 213 integrally formed with the worm wheel 211 rotates.

The active front wheel steering device of the vehicle may control the first motor 111 by controlling the first motor 111 even when the driver operates the steering wheel 101 at a certain angle as the driver operates the steering wheel 101. The rotation angle of the output shaft 217 is smaller than the rotation angle of the input shaft 215 to maintain steering stability.

On the other hand, the active front wheel steering device of the vehicle, when the vehicle is in a low speed state for parking or the like, even if the driver manipulates the input shaft 215 at an angle as the driver operates the steering wheel 101, the ECU 125 is the first motor By controlling the 111, the rotation angle of the output shaft 217 is made larger than the rotation angle of the input shaft 215 so that the driver can operate the steering wheel at a small angle.

The active front wheel steering apparatus for a vehicle according to the prior art is provided with a planetary gear device composed of a sun gear 213, a planetary gear 203 and a ring gear 205 as the gear ratio converting device 109.

The sun gear 213 and the planetary gear 203 are generally formed as helical gears. As shown in FIG. 2B, the helical gears are formed while the rows of gear teeth are inclined at an angle, not parallel to the rotation axis of the gears.

These helical gears are able to transmit more force because the gear teeth engaged with each other have a longer length as compared with the case where the gear teeth are parallel to the axis of rotation of the gear, and the heat of the gear teeth is inclined. It will rotate smoothly.

However, in the gear ratio converter 109 according to the related art, since the input shaft 215 has a structure for rotating the carrier 201 through the sun gear 213, the field gear 213 to satisfy the strength of the input shaft. There was a limit to reduce the size of), and accordingly, there was a limit to reducing the size of the entire planetary gear device, and the assembly process also had a difficult problem.

In order to solve this problem, the present invention, unlike the conventional variable gear ratio planetary gear device in which the carrier is the first input, the sun gear is the second input, and the ring gear is output, the first input and the output are first sun gear and the first gear, respectively. Unlike the conventional input shaft penetrating the sun gear by the two sun gear is responsible for the present invention, since the input shaft does not have to penetrate the first sun gear, it is possible to reduce the radial size of the planetary gear device and to improve the assembly The object is to provide a gear ratio planetary gear device.

In order to achieve the above object, the present invention provides a variable gear ratio planetary gear device comprising a first sun gear, a first planet gear external to the first sun gear, and a first ring gear inscribed with the first planet gear. A first planetary gear device; A second planetary gear device including a second sun gear, a second planetary gear external to the second sun gear, and a second ring gear inscribed with the second planetary gear; A shared carrier disposed between the first planetary gear device and the second planetary gear device and supporting the first planetary gear and the second planetary gear, respectively; A rotational force assistance device for selectively transmitting rotational force to the first ring gear or the second ring gear; And a housing that surrounds the first planetary gear device, the second planetary gear device, and the shared carrier.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

3 is a schematic sectional view of a variable gear ratio planetary gear device according to an embodiment of the present invention. As shown in FIG. 3, the variable gear ratio planetary gear device according to the embodiment of the present invention may include a first planetary gear device 300. And a second planetary gear device 310, a shared carrier 320, a rotational force assisting device 330, and a housing 340.

The first planetary gear device 300 receives a rotational force from the input shaft 215 and the rotational force assisting device 330.

The first planetary gear device 300 includes a first sun gear 301, a first planetary gear 303 external to the first sun gear 301, and a first ring gear inscribed with the first planetary gear 303 ( 305).

The first sun gear 301 is formed at the end of the input shaft 215 and rotates by the driver's steering wheel, and serves as the first steering input unit in the variable gear ratio planetary gear device according to the embodiment of the present invention.

Since the first planetary gear 303 is external to the first sun gear 301, the first planetary gear 303 rotates in conjunction with the first sun gear 301.

The number of the first planetary gears 303 is generally provided with two to three in consideration of the input load and the like, but more than that may be possible.

A bearing is mounted between the first planetary gear 303 and the first support shaft 304 such that the first planetary gear 303 rotates relative to the first support shaft 304 and the first planetary gear 303 Is rotatably supported by the shared carrier 320 because it is connected to the shared carrier 320 via a first support shaft 304 that is press-fit / fixed to the shared carrier 320.

In addition, since the first planetary gear 303 is inscribed with the first ring gear 305, the first planetary gear 303 rotates in cooperation with the first ring gear 305.

The first ring gear 305 is inscribed with the first planetary gear 303 while being fixed inside the worm wheel 331 and configured to rotate with the worm wheel 331.

The second planetary gear device 310 is the driver input angle transmitted to the first planetary gear device 300 via the input shaft 215 and the motor input angle transmitted to the first planetary gear device 300 via the worm wheel 331. It serves as a steering output unit for transmitting to the rack-pinion gear unit (not shown) as the output angle through the output shaft 217.

Here, the output angle consists of the sum or difference of the driver input angle (rotation angle of the input shaft according to the steering wheel operation of the driver) and the motor input angle (rotation angle of the worm wheel according to the rotation of the worm).

The second planetary gear device 310 includes a second sun gear 315, a second planetary gear 311 external to the second sun gear 315, and a second ring gear inscribed with the second planetary gear 311. 313).

A bearing is mounted between the second planetary gear 311 and the second support shaft 312 so that the second planetary gear 311 rotates relative to the second support shaft 312, and the second planetary gear 311 is rotated. Is rotatably supported by the shared carrier 320 because it is connected to the shared carrier 320 via a second support shaft 312 that is press-fit / fixed to the shared carrier 320.

In addition, the second planetary gear 311 is inscribed with the second ring gear 313 and circumscribed with the second sun gear 315.

The second ring gear 313 is formed to be inscribed with the second planetary gear 311 and is fixed to the housing 340.

In the embodiment of the present invention, the first ring gear 305 is fixed to the worm wheel 331 is rotated in conjunction with the worm wheel 331 and the second ring gear 313 is shown in the case of being fixed to the housing 340, It is not necessarily limited thereto.

That is, the rotational force assisting device 330 is provided on the side of the second planetary gear device 310 and the second ring gear 313 is fixed to the worm wheel 331 to rotate in conjunction with the worm wheel 331 and the first ring gear ( 305 may be secured to housing 340.

However, one of the first ring gear 305 or the second ring gear 313 must be restrained without being rotated by being fixed to the housing 340 to obtain a desired gear ratio.

The second sun gear 315 is rotated by receiving rotational force from the second planetary gear 311 externally to the second planetary gear 311, thereby finally racking the steering angle transmitted from the first planetary gear device 300. Transmission to the pinion gear portion (not shown).

On the other hand, the second sun gear 315 is preferably formed coaxially with the first sun gear 301.

The shared carrier 320 is disposed between the first planetary gear device 300 and the second planetary gear device 310, and the first support shaft 304 and the second support shaft 312 are press-fitted / fixed to form a first The first planetary gear 303 and the second planetary gear 311 are rotatably supported through the support shaft 304 and the second support shaft 312, respectively.

In addition, the shared carrier 320 rotates in conjunction with the rotation of the first planetary gear 303 while transmitting a rotational force to the second planetary gear 311.

That is, the shared carrier 320 serves to convert the output of the first planetary gear device 300 into the input of the second planetary gear device 310.

The shared carrier 320 is preferably formed in a plate shape having a predetermined thickness, but is not necessarily limited thereto. The first planetary gear 303 and the second planetary gear 311 fixed / coupled to the shared carrier 320 may be used. Depending on the number of) can be produced in a variety of shapes, such as long bar, triangle, square.

In addition, the thickness of the shared carrier 320 is suitably larger than the sum of the length of the first support shaft 304 press-fitted / fixed on one side and the length of the second support shaft 312 press-fitted / fixed on the other side It is preferable, but not necessarily limited thereto.

That is, when the extension line of the first support shaft 304 and the extension line of the second support shaft 312 are shifted from each other, the first support shaft 304 and the second support shaft 312 are press-fitted to the shared carrier 320. Since both axes do not meet with each other even if fixed, the thickness of the shared carrier 320 may be made smaller than in the above case.

The rotational force assisting device 330 includes a worm wheel 331 and a worm 333 and a worm 333 engaged with the worm wheel 331, which are selectively coupled to the first ring gear 305 or the second ring gear 313. It is configured to include a motor (not shown) for driving.

However, when the second ring gear 313 is fixed to the worm wheel 331 to rotate in conjunction with the worm wheel 331 and the first ring gear 305 is fixed to the housing 340, the rotational force assistance device 330 Will provide auxiliary rotational force to the second planetary gear device 310.

The rotational force assistance device 330 provides a motor input angle to the first planetary gear device 300 by the rotation of the worm wheel 331 according to the rotation of the worm 333 connected to the motor (not shown).

Here, the motor input angle means a rotation angle of the worm wheel according to the rotation of the worm, which is determined according to the rotation direction and the rotation speed of the worm wheel.

The worm wheel 331 has a shape surrounding the first planetary gear device 300, but the first ring gear 305 is fixed to the inner circumferential surface thereof.

The worm 333 rotates by engaging the worm wheel 331 and rotates the worm wheel 331, and may be connected to various rotational force providing devices including a motor.

Hereinafter, an example in which the first planetary gear device 300, the second planetary gear device 310, and the rotational force assisting device 330 operate will be described with reference to FIG. 3.

First, the second planetary gear device 310 has an input with a shared carrier 320, an output with a second sun gear 315, and a second ring gear 313 is fixed to the housing 340.

In addition, the first planetary gear device 300 has an input of a first sun gear 301 and a worm wheel 331, an output of a shared carrier 320, and a first ring gear 305 is fixed to the worm wheel 331 so that the worm wheel is fixed. It rotates in the same direction as the rotation direction of 331, the rotation direction and the rotational speed of the worm wheel 331 depends on the rotational direction and rotational speed of the motor (not shown) and the worm 333 connected thereto.

Here, the output of the shared carrier 320 by the driver input angle transmitted to the first sun gear 301 through the input shaft 215 and the motor input angle transmitted to the first ring gear 305 through the worm wheel 331. The angle is determined, and it is variously determined according to the rotational direction and rotation speed of the worm wheel 331 and the gear ratio of each of the first sun gear 301, the first planetary gear 303, and the first ring gear 305.

In addition, in the second planetary gear device 10, since the input is the shared carrier 320 and the output is the second sun gear 315, the output angles of the second sun gear 315 are also the second sun gear 315, the second. Various determinations are made according to the gear ratios of the planetary gears 311 and the second ring gear 313.

Accordingly, the final output angle (ie, the output angle of the second sun gear 315) constitutes the driver input angle through the input shaft 215 and each of the first planetary gear device 300 and the second planetary gear device 310. It is determined by the gear ratio of the gears and the motor input angle transmitted to the first ring gear 305 through the worm wheel 331.

For example, the gear ratios of the first planetary gear device 300 and the second planetary gear device 310 of the present invention are calculated through a gear ratio calculation formula.

First, the gear ratio calculation formula of the first planetary gear device 300 is as follows.

The gear ratio calculation formula of the second planetary gear device 310 is as follows.

At this time, Z1, Z2, Z3 represents the number of gear teeth of the first sun gear 301, the first planet gear 303, and the first ring gear 305 of the first planetary gear device 300, respectively. , Z6 represents the number of gear teeth of the second sun gear 315, the second planet gear 311, and the second ring gear 313 of the second planetary gear device 310, respectively.

In one embodiment, applying gear teeth with Z1 = 19, Z2 = 17, Z3 = 53, Z4 = 15, Z5 = 22, Z6 = 59 calculates I1 = 0.264, I2 = 4.933 and the total gear ratio is I1 and I2. Since the product is 1.302, the output is increased compared to the input.

Therefore, in the above case, the angle at which the output shaft rotates is larger than the angle at which the driver rotates the steering wheel, so that the driver can operate the steering wheel at a small angle when parking.

The above description exemplarily illustrates the technical idea of the present invention, and those skilled in the art may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

As described above, according to the present invention, unlike the conventional variable gear ratio planetary gear device having the carrier as the first input, the sun gear as the second input, and the ring gear as the output, the first input and the output are respectively compared with the first sun gear. Unlike the conventional input shaft penetrating the sun gear by the second sun gear, the input shaft does not have to penetrate the first sun gear in the present invention, thereby reducing the radial size of the planetary gear device and improving the assemblability. .

Claims (5)

In the variable gear ratio planetary gear device, A first planetary gear device comprising a first sun gear and a first planetary gear external to the first sun gear and a first ring gear inscribed with the first planetary gear, the second sun gear and the second sun gear. A second planetary gear device comprising a second planetary gear that is circumscribed and a second ring gear that is inscribed with the second planetary gear, disposed between the first planetary gear device and the second planetary gear device, the first planetary gear device And a rotational force assisting device for selectively transmitting power to a shared carrier supporting the second planetary gear, respectively, the first ring gear or the second ring gear, the first planetary gear device and the second planetary gear device; A housing surrounding the shared carrier, The first planetary gear device receives a rotational force from an input shaft and the rotational force assisting device, the shared carrier converts the output of the first planetary gear device into an input of the second planetary gear device, One side of the shared carrier is press-coupled to the first support shaft to rotate relative to the first planetary gear, the other side of the shared carrier is characterized in that the second support shaft to rotate relative to the second planetary gear is press-coupled. Variable gear ratio planetary gear device. The method of claim 1, Bearings are mounted between the first planetary gear and the first support shaft and between the second planetary gear and the second support shaft, respectively, and the extension line of the first support shaft and the extension line of the second support shaft are shifted. Variable gear ratio planetary gear device, characterized in that the press-fit coupled to the carrier. delete delete delete

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