JP2009063138A - Multistage variable-speed planet gear train - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the mounting performance of a transmission to a vehicle, in a forward eight-stage multistage variable-speed planet gear train. <P>SOLUTION: The multistage variable-speed planet gear train is constituted in such a manner that: the train comprises an output shaft 12 coaxial with an input shaft 10, a sub-shaft 14 and an intermediate output shaft 16 which are parallel with these shafts, a first planet gear set 24 coaxial with the output shaft 12, and a second planet gear set 26 coaxial with the sub-shaft 14; the input shaft 10 is connectable to a second sun gear 40 and a second ring gear 42 via a speed-reducing gear pair 10a, 28, and also connectable to a first ring gear 32 and a first sun gear 30; the output shaft 12 and the sub-gear 14 are connected to each other via connecting gears 12a, 14a; the output shaft 12 and the sub-shaft 14 are connected to the first ring gear 32 and a second carrier 48, respectively; the first sun gear 30 and the second sun gear 40 can be connected and fixed with each other via a second gear pair 30a, 40a; a first carrier 38 is fixable; the first connecting gear 12a is engaged with the input gear 16a; and thus the train is enabled to perform an output. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planetary gear train that can be used for a vehicular automatic transmission and capable of multi-stage shifting.

As a planetary gear train used for an automatic transmission for vehicles, a gear train capable of multi-speed shifting of eight forward speeds has been proposed mainly for improving the fuel efficiency, exhaust characteristics, acceleration performance, and the like of the vehicle.
As a conventional planetary gear train capable of such a multi-stage shift, there is a multi-speed planetary gear train proposed by the present applicant. This gear train is composed of a planetary gear set and six friction elements on two axes. By arranging them separately, the axial length is shortened, and an eight-speed forward gear ratio that can be easily mounted on a horizontally mounted front wheel drive vehicle or the like is obtained. (See Patent Document 1).

However, the conventional planetary gear train has two sets of planetary gears, three sets of gear pairs, and six friction elements in order to obtain an eight-speed forward gear ratio. Although the transmission shaft dimension is shortened by arranging the transmission gears separately, as shown in FIG. 1 of Patent Document 1, a pair of reduction gears arranged on the output shaft 12 side provided in parallel with the input shaft 10. The outer diameter of 40 has to be large, and the output shaft 12 has its center position determined by the relationship between the output gear 12a integrated therewith and the counterpart gear (an output gear coaxial with the axle not shown). In addition, there is a problem that the large-diameter portion of the gear pair 40 for reduction has to be set at a position where it interferes with the vehicle side, and there is a problem that the mounting of the transmission on the vehicle is limited in space. .
JP 2005-023987

The problem to be solved is that the speed reduction gear pair 40 arranged on the output shaft 12 side provided in parallel with the input shaft 10 has a large outer diameter and the center position of the gear pair 40 is limited. It is a point that there are restrictions on the installation of the vehicle on the vehicle.
An object of the present invention is to provide a multi-speed planetary gear train that can be easily mounted on an engine laterally-mounted front wheel drive vehicle or the like by increasing the degree of freedom of arrangement of a shaft having a gear that tends to increase in outer diameter.

  The multi-stage planetary gear train of the present invention is provided with an input shaft, an output shaft provided coaxially with the input shaft, an auxiliary shaft provided parallel to the input shaft and the output shaft, and parallel to the input shaft and the output shaft. An intermediate output shaft is disposed coaxially with the input shaft and the output shaft, and the first pinion and the first pinion engaged with the first sun gear, the first ring gear, the first ring gear, and the first sun gear are rotatably supported. A first planetary gear set comprising one carrier and a second sun gear, a second sun gear, a second sun gear, a second sun gear, a second sun gear, a second sun gear, and a second sun gear, which are arranged coaxially with the countershaft. A second planetary gear set comprising a second carrier, and the input shaft can be coupled to the second sun gear and the second ring gear via a first gear pair for reduction, respectively, The sun gear can be connected to each other. The output shaft and the counter shaft are connected by a first connecting gear integrated with the output shaft and a second connecting gear integrated with the counter shaft, and the output shaft is connected by the first ring gear. The countershaft is connected to the second carrier, the first sun gear and the second sun gear are connected via the second gear pair and can be fixed to the stationary part, and the first carrier can be fixed to the stationary part, The first connecting gear meshes with the input gear integrated with the intermediate output shaft, and the driving force from the output shaft is output to the wheels via the input gear.

  Since the multi-speed planetary gear train of the present invention is configured as described above, the degree of freedom of arrangement of the countershafts is increased, and a position where a gear having a large diameter of the first gear pair can be prevented from interfering with the vehicle side. As a result, it becomes easy to mount the engine on a horizontally mounted front-wheel drive vehicle or the like.

  Hereinafter, a multi-speed planetary gear train according to an embodiment of the present invention will be described with reference to the drawings based on examples.

FIG. 1 is a skeleton diagram showing a planetary gear train according to an embodiment of the present invention.
In the multi-speed planetary gear train of the embodiment shown in FIG. 1, the input shaft 10 and the output shaft 12 driven from the engine 1 via the torque converter 2 are on the same shaft as the output shaft 1a of the engine 1, and The auxiliary shaft 14 and the intermediate output shaft 16 are arranged in parallel with these.

A first connecting gear 12a and a second connecting gear 14a are integrated with the output shaft 12 and the sub shaft 14, respectively, and the output shaft 12 and the sub shaft 14 are connected to each other by meshing with each other.
The first connecting gear 12a is also meshed with the input gear 16a integral with the intermediate output shaft 16, and the drive gear 16b integral with the intermediate output shaft 16 is meshed with the output gear 18.
The output gear 18 drives the axles 22a and 22b via the differential device 20, and the axles 22a and 22b are connected to left and right wheels (not shown).

The reduction gear 10a integrated with the input shaft 10 has a diameter larger than that of the reduction gear 10a and meshes with an input gear 28 that is coaxially rotatable with the auxiliary shaft 14, and the reduction gear 10a and the input gear 28 are the main gears. The first gear pair for reduction of the invention is configured.
A first planetary gear set 24 is coaxially disposed on the output shaft 12 and a second planetary gear set 26 is coaxially disposed on the auxiliary shaft 14.

Both the first planetary gear set 24 and the second planetary gear set 26 are generally called single pinion types, and each has the same configuration.
That is, the first planetary gear set 24 allows the first sun gear 30, the first ring gear 32, the plurality of first pinions 34 engaged with the first ring gear 32 and the first sun gear 30, and the first pinion 34 to freely rotate. The rotating member is a first carrier 38 that is pivotally supported.
Similarly, the second planetary gear set 26 includes rotating members such as a second sun gear 40, a second ring gear 42, a plurality of second pinions 44, and a second carrier 48.

The rotating members of the input shaft 10, the input gear 28, the output shaft 12, the counter shaft 14, the first planetary gear set 24, and the second planetary gear set 26 are connected as follows or can be connected.
The second gear 30 a connected integrally with the first sun gear 30 meshes with the second gear 40 a integrated with the second sun gear 40. The second gear 30a and the second gear 40a constitute the second gear pair of the present invention. Therefore, the first sun gear 30 and the second gear 40 are connected via the second gear pair.

The input gear 28 is connected to the second ring gear 42 when the first clutch 50 is engaged. Similarly, when the second clutch 52 is engaged, the input gear 28 is connected to the second sun gear 40.
The second carrier 48 is connected to the countershaft 14.

The second sun gear 40 can be fixed to the case (stationary portion) 56 by fastening the first brake 54, whereby the second sun gear 40 and the first sun gear 30 connected thereto are fixed together.
Further, the first sun gear 30 can be connected to the input shaft 10 by the third clutch 58, whereby the first sun gear 30 and the second sun gear 40 connected thereto are both connected to the input shaft 10.
The first carrier 38 can be connected to the input shaft 10 via the fourth clutch 60, and can be fixed to the case 56 by fastening the second brake 62.
The first ring gear 32 is connected to the output shaft 12.

Next, the operation of the planetary gear train of the embodiment shown in FIG. 1 will be described with reference to the operation table shown in FIG.
In the following description, the clutch and the brake are referred to as a friction element, and those having a connecting function between any of the shaft, the stationary part, and the rotating member are collectively referred to as a fastening element.

  In the operation table of FIG. 3, fastening elements such as clutches and brakes are assigned to the horizontal columns, C-1 represents the first clutch 50, B-1 represents the first brake 54, and so on. The relationship between these symbols and the symbols of the respective fastening elements is shown in FIG.

The vertical column of the operation table is divided into “D range” and “R range” of an operation lever (not shown). The D range is forward first speed (1st) to eighth speed (8th), and the R range is reverse ( R-1 and R-2) are assigned.
In the operation table of FIG. 3, “o” represents the fastening of each fastening element, and the blank represents the release of each fastening element.

  Here, regarding the calculation of each gear ratio, in the planetary gear set, the ratio (Zs / Zr) of the number of teeth (Zs) of the sun gear to the number of teeth (Zr) of the ring gear α1 and α2 in the second planetary gear set 26, and in the gear pair, the gear ratio of the first gear pair for reduction (the number of teeth of the input gear 28 / the number of teeth of the reduction gear 10a) is i1, second. The gear ratio of the gear pair (the number of teeth of the second gear 40a / the number of teeth of the second gear 30a) is i2, and the gear ratio of the first connecting gear 12a and the second connecting gear 14a (the number of teeth of 14a / 12 teeth). The number is described as i3.

Here, for calculation of each gear ratio, each gear ratio is set to 0.50, α2 is 0.45, i1 is 2.02, i2 is 1.06, and i3 is 0.987. The case is illustrated.
In order to simplify the display and calculation formula, α2 · i1 (1 + α1) / {α1 · i2 + α2 · i1 (1 + α1)} is defined as A. In the above-mentioned tooth number ratio, A is 0.718. The transmission ratio is represented by the ratio of the rotational speed of the input shaft 10 to the rotational speed of the output shaft 12 (the rotational speed of the input shaft 10 / the rotational speed of the output shaft 12).

First, the forward first speed (1st) is driven by connecting the second ring gear 32 to the input gear 28 by engaging the first clutch 50 (C-1) as seen in the operation table shown in FIG. The first carrier 38 is fixed to the case 56 by fastening the second brake (B-2) 62. The engagement of the first clutch 50 is maintained up to the fifth speed in the subsequent shift.
The gear ratio of the first speed is i1 (1 + α2) / i3 + i1 · α2 / (α1 · i2), and the gear ratio set to the above value is 4.667.

Next, shifting to the second speed (2nd) is performed by releasing the engagement of the second brake 62 at the first speed and engaging the first brake 54 (B-1) to place the second sun gear 30 in the case. This is done by fixing to 56.
The speed ratio of the second speed is i1 (1 + α2) / i3, which is 2.968 in the above-described gear ratio.

Next, the shift to the third speed (3rd) is performed by releasing the engagement of the first brake 54 at the second speed and engaging the second clutch 52 (C-2).
As a result, the second planetary gear set 26 is united and the gear ratio is i1 / i3.
In the above-mentioned tooth number ratio, it is 2.047.

Next, the shift to the fourth speed (4th) is performed by releasing the engagement of the second clutch 52 at the third speed and engaging the third clutch 58.
The speed ratio of the fourth speed is i1 · i2 (1 + α2) / {i2 (1 + α2) + α2 (i1-i2)}.
In the above-mentioned tooth number ratio, it is 1.584.

Next, the shift to the fifth speed (5th) is performed by releasing the engagement of the third clutch 58 at the fourth speed and engaging the fourth clutch 60 (C-4).
The engagement of the fourth clutch 60 is maintained at the subsequent high speed.
The speed ratio of the fifth speed is A / (1 + α1) + i1 (1-A) (1 + α2) / i2.
In the above-mentioned tooth number ratio, it becomes 1.250.

Next, the shift to the sixth speed (6th) is performed by releasing the engagement of the first clutch 50 up to the fifth speed and engaging the third clutch 58 again.
As a result, the first planetary gear set 14 is integrated with the input shaft 10, so that the gear ratio is 1.000 irrespective of the gear ratio.

Next, the shift to the seventh speed (7th) is performed by releasing the engagement of the third clutch 58 at the sixth speed and engaging the second clutch 52 again.
As a result, the gear ratio is i1 / {i1 + α1 (i1−i2)}, and the above gear ratio is 0.810 (overdrive).

Next, the shift to the eighth speed (8th) is performed by releasing the engagement of the second clutch 52 at the seventh speed and engaging the first brake 54 again.
As a result, the gear ratio is i1 / (1 + α1), and the speed increase is 0.667 in the aforementioned gear ratio.

Next, the reverse first speed (R-1) of the R range is changed by engaging the second clutch 52 and the second brake 52.
As a result, the gear ratio becomes −i1 / (α1 · i2), and the above-mentioned gear ratio becomes −3.776.

The reverse second speed (R-2) is changed by engaging the third clutch 58 and the second brake 52.
As a result, the gear ratio becomes −1 / α1, and in the above-mentioned gear ratio, it becomes −2,000.

As described above, the multi-stage planetary gear train according to the first embodiment of the present invention can obtain a gear ratio of 8 forward speeds and 2 reverse speeds preferable for an automobile, and the input gear 28 having a large outer diameter is located on the countershaft 14. If the center distance between the input shaft 10 and the output shaft 12 is maintained, the degree of freedom in arrangement becomes much higher than that in the prior art.
This is because the first connecting gear 12a is configured to mesh with the input gear 16a and output via the intermediate output shaft 16, so that the arrangement of the auxiliary shaft 14 becomes free.
This makes it easy to set the countershaft 14 at a position where the input gear 28 does not interfere with the vehicle side, and space constraints for mounting the transmission equipped with this planetary gear train are reduced.

FIG. 3 shows a skeleton diagram of a multi-stage planetary gear train according to the second embodiment of the present invention, and corresponds to FIG.
Here, the description will focus on parts that are different from the first embodiment, the same reference numerals are given to parts that are substantially the same as those of the first embodiment, and descriptions thereof are omitted.

The difference of the second embodiment from the first embodiment is that the first carrier 38 can be connected to the sleeve 64 via the fourth clutch 60, and the sleeve 64 can be moved left and right in the axial direction by an actuator (not shown). It is that.
In other words, the sleeve 64 can be connected to the input shaft 10 when moved to the left and can be connected to the case 56 when moved to the right.

Accordingly, when the fourth clutch 60 is engaged after moving the sleeve 64 to the left, the input shaft 10 and the first carrier 38 are connected, and when the fourth clutch 60 is engaged after moving the sleeve 64 to the right, the first clutch 60 is engaged. The carrier 38 is fixed to the case 56.
Therefore, the fourth clutch 60 also functions as the second brake 62 in the first embodiment, and the number of friction elements is reduced by one as compared with the first embodiment.

Next, the operation of the second embodiment will be described with reference to the operation table shown in FIG.
The operation table of FIG. 4 is the same as that of the first embodiment shown in FIG. 2 except for the column in which the sleeve 64 is displayed as “S”, and the column of S represents the moving direction of the sleeve 64 with arrows indicating left and right. Yes.
In other words, the sleeve 64 moves to the right in the first forward speed and the reverse speed, and the first carrier 38 is fixed to the case 56 in combination with the engagement of the fourth clutch 60. In other words, the first carrier 38 can be connected to the input shaft 10 in combination with the engagement of the fourth clutch 60 by moving to the left side.

An arrow enclosed in parentheses indicates that the sleeve 64 is moving but is not involved in power transmission.
In addition, “*” mark is written in the “S” column of the third speed. This indicates that the left / right movement of the sleeve is switched in accordance with the next expected shift at the third speed, but the movement operation is not limited to the third speed, but is performed at the second speed or the fourth speed. Also good.

Also in the second embodiment, the forward gear ratio and the reverse gear ratio can be obtained by switching the engagement of the friction elements according to the operation table shown in FIG. Since the calculation formulas for the respective gear ratios are the same as those described in the first embodiment, description thereof is omitted.
Thus, in the second embodiment as well, a transmission gear ratio of 8 forward speeds and 2 reverse speeds preferable for an automobile can be obtained, and the input gear 28 having a large outer diameter is on the auxiliary shaft 14, and the shaft has a degree of freedom of arrangement. Becomes higher.
This is because the first connecting gear 12a is configured to mesh with the input gear 16a and output via the intermediate output shaft 16, so that the arrangement of the auxiliary shaft 14 becomes free.
This makes it easy to set the countershaft 14 at a position where the input gear 28 does not interfere with the vehicle side, and space constraints for mounting the transmission equipped with this planetary gear train are reduced.

  Further, as described above, the number of friction elements is one less than that in the first embodiment. This means that the number of friction elements that are not fastened at each shift stage is small. In general, the frictional elements that are not engaged are factors that cause the drag resistance to deteriorate the power transmission efficiency. In particular, since the second brake 62 in the first embodiment has a large torque capacity, its influence is large. Since the planetary gear train of the second embodiment substantially eliminates the second brake 762 in the first embodiment, the planetary gear train of the second embodiment has improved power transmission efficiency compared to the first embodiment.

  As described above, the multi-stage planetary gear train according to each embodiment of the present invention can obtain a forward gear ratio of 8 forwards and 2 reverse gears preferable for an automobile, and a transmission equipped with this planetary gear train is mounted on a vehicle. Therefore, the mounting on various vehicles becomes easy.

In each of the above embodiments, the torque converter 2 is provided between the engine 1 and the input shaft 10, but it goes without saying that a fluid coupling or a friction clutch may be used instead.
Further, as is generally done with an automatic transmission, a one-way clutch can be provided in parallel with the second brake 62 to facilitate shift control from the first speed to the second speed.

In the above description, the first planetary gear set 24 is an example of a single pinion type constituted by the first sun gear 30, the first ring gear 32, the plurality of first pinions 34, and the first carrier 38. A similar function can be obtained as a so-called double pion type planetary gear set.
When the first planetary gear set 24 is a double-pion type planetary gear set, the first ring gear 32 and the first carrier 38 may be replaced with respect to the above description.
Furthermore, although the above description has been given for the case of eight forward speeds and two reverse speeds, the present invention is not limited to this. For example, the third clutch 58 may be omitted from the above description to provide six forward speeds and one reverse speed.

  Since the input gear 28 having a forward gear ratio of 8 steps and a large outer diameter has a degree of freedom in placement, it is easy to mount a transmission equipped with this planetary gear train. Therefore, it can be widely applied to small passenger cars where fuel efficiency is important.

It is the skeleton figure which showed the multi-stage planetary gear train of this invention. Example 1 It is a figure which shows the operation | movement table | surface of the multistage speed planetary gear train of Example 1. FIG. It is the skeleton figure which showed the multi-stage planetary gear train of this invention. (Example 2) It is a figure which shows the operation | movement table | surface of the multistage speed planetary gear train of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 10 Input shaft 12 Output shaft 14 Sub shaft 16 Intermediate output shaft 18 Output gear 20 Differential gear 22 Axle 24 First planetary gear set 26 Second planetary gear set 28 Input gear 30 First sun gear 32 First ring gear 34 1st pinion 38 1st carrier 40 2nd sun gear 42 2nd ring gear 44 2nd pinion 48 2nd carrier 50 1st clutch 52 2nd clutch 54 1st brake 56 case 58 3rd clutch 60 4th clutch 62 2nd brake 64 sleeve

Claims (2)

An input shaft;
An output shaft provided coaxially with the input shaft;
A secondary shaft provided in parallel with the input shaft and the output shaft;
An intermediate output shaft provided in parallel with the input shaft and the output shaft;
The first sun gear, the first ring gear, the first ring gear, the first pinion meshed with the first sun gear, and the first carrier that rotatably supports the first pinion are arranged coaxially with the input shaft and the output shaft. A first planetary gear set;
A second planetary gear which is arranged coaxially with the sub-shaft and is composed of a second sun gear, a second ring gear, a second ring gear and a second pinion meshing with the second sun gear, and a second carrier which rotatably supports the second pinion. A pair and
The input shaft can be connected to the second sun gear and the second ring gear via a first gear pair for reduction, and can be connected to the first ring gear and the first sun gear, respectively.
The output shaft and the counter shaft are connected by a first connection gear integral with the output shaft and a second connection gear integral with the counter shaft,
The output shaft is connected to the first ring gear;
The countershaft is connected to the second carrier;
The first sun gear and the second sun gear are connected via a second gear pair and can be fixed to a stationary part,
The first carrier can be fixed to a stationary part;
The multi-stage planetary gear train, wherein the first connecting gear meshes with an input gear integral with the intermediate output shaft and outputs a driving force from the output shaft to a wheel via the input gear.   The first carrier is connected to a sleeve via a clutch, the sleeve is connected to the input shaft by moving in one axial direction, and is fixed to the stationary portion by moving in the other axial direction. The multi-speed planetary gear train according to claim 1, wherein

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