JP2009250327A - Multi-stage shift planetary gear train - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve fuel economy by achieving of power transmission efficiency in a multi-stage planetary gear train having at least forward 8-speed. <P>SOLUTION: A multi-stage planetary gear train is provided with an input axis 10, an output axis 12, and three sets of single pinion type planetary gear set 14, 16, and 18. The input axis 10 is coupled to a first carrier 28, the output axis 12 is coupled to a second ring gear 32 and a third carrier 48, a first sun gear 20 can be coupled to a second sun gear 30, a first ring gear 22 is coupled to a third sun gear 40, the second sun gear 30 can be fixed to a stationary portion 54, a second carrier 38 can be coupled to the third sun gear 40 and a third ring gear 42 and can be fixed to the stationary portion 54 without coupling to the third ring gear 42, the third ring gear 42 can be fixed to the stationary portion 54, and the first planetary gear set 14 can be integrated by the clutch 50. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a planetary gear train that can be used for an automatic transmission for a vehicle such as an automobile 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 multi-speed shifting, there is a set of double-pinion type planetary gears and a planetary gear group called Ravigneaux type, and a multi-speed planetary gear train consisting of six friction elements. As the gear train, a planetary gear train is known in which a gear ratio of eight forward speeds is obtained by switching so as to always fasten two of the six friction elements. (See Patent Document 1).

However, the above conventional planetary gear train requires a double pinion type planetary gear in order to obtain a preferable gear ratio for a forward eight-stage automobile, and therefore has a higher manufacturing cost than a so-called single pinion type planetary gear. On the other hand, there is a problem that the power transmission efficiency is poor due to the large meshing of the gears. On the other hand, since four of the six friction elements are always idle, the drag torque of the idle friction element is large. Therefore, coupled with the problem that the power transmission efficiency is poor, there is a problem that the fuel consumption of the automobile is bad and the heat generation is large.
Japanese Patent No. 3777929

The problem to be solved is that when a planetary gear train having eight or more forward stages is obtained, a double pinion type planetary gear with poor power transmission efficiency is required and four friction elements are always idle. The fuel consumption is bad and the heat generation is high.
An object of the present invention is to use a single pinion type planetary gear to obtain a gear stage exceeding eight forward speeds while ensuring a preferable gear ratio for a vehicle such as an automobile. In this case, friction that is always idle An object of the present invention is to provide a multi-speed planetary gear train that can reduce fuel consumption and heat generation by reducing the number of elements.

The multi-stage planetary gear train of the present invention includes an input shaft, an output shaft, a first pinion that is arranged coaxially with the input shaft, and meshes with the first sun gear, the first ring gear, the first ring gear, and the first sun gear. A first planetary gear set having a first carrier that rotatably supports one pinion, and a first sun gear, a second ring gear, a second ring gear, a second ring gear, and a second sun gear that are arranged coaxially with the output shaft. A second planetary gear set including a second pinion, a second carrier that rotatably supports the second pinion, and a coaxial arrangement with an output shaft; a third sun gear, a third ring gear, the third ring gear, and a third A third pinion meshed with the sun gear, a third planetary gear set having a third carrier that rotatably supports the third pinion, an input shaft connected to the first carrier, and an output shaft connected to the second carrier Ring gear The first sun gear can be connected to the second sun gear, the first ring gear can be connected to the third sun gear, the second sun gear can be fixed to the stationary part, and the second carrier can be connected to the third carrier. The sun gear and the third ring gear can be connected to each other and can be fixed to the stationary part without being connected to the third ring gear, the third ring gear can be fixed to the stationary part, and the first planetary gear set is integrated by a clutch. It was configured to be possible.

  Since the multi-speed planetary gear train of the present invention is configured as described above, a planetary gear train having more than 8 forward speeds using a single pinion type having high power transmission efficiency while obtaining a preferable gear ratio for a transmission for an automobile or the like. In this case, the number of friction elements that are always free-wheeling can be reduced to three, which is one less than that of the conventional example, so that improvement in fuel consumption and heat generation can be expected.

  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 the first embodiment of the present invention.
In the multi-speed planetary gear train of the embodiment shown in FIG. 1, an input shaft 10 driven from the engine 1 via the torque converter 2 and an output shaft 12 that drives a drive wheel (not shown) are connected to the output shaft 1 a of the engine 1. On the same axis.

The first planetary gear set 14, the second planetary gear set 16, and the third planetary gear set 18, which are arranged coaxially with the input shaft 10 and the output shaft 12 in order from the upstream side to the downstream side, are generally These are called single pinion types, and each has the same configuration.
That is, the first planetary gear set 14 is capable of rotating the first sun gear 20, the first ring gear 22, the plurality of first pinions 24 meshed with the first ring gear 22 and the first sun gear 20, and the first pinion 24. The rotating member is a first carrier 28 that is pivotally supported.

  Similarly, the second planetary gear set 16 is composed of rotating members such as a second sun gear 30, a second ring gear 32, a plurality of second pinions 34, and a second carrier 38. The rotating member includes a three sun gear 40, a third ring gear 42, a plurality of third pinions 44, and a third carrier 48.

Next, the connection relationship among the rotating members of the input shaft 10, the output shaft 12, the first planetary gear set 14, the second planetary gear set 16, and the third planetary gear set 18 will be described.
The input shaft 10 is connected to the first carrier 28.
The first sun gear 20 can be connected to the first ring gear 22 by the first clutch 50. In addition, when the 1st clutch 50 is fastened, the 1st planetary gear set 14 will be united (namely, the state in which all the rotation members rotate integrally).
The first ring gear 22 is connected to the third sun gear 40.

The second sun gear 30 can be fixed to a transmission case (stationary portion) 54 by a first brake 52 and can be connected to the first sun gear 20 by a second clutch 56.
The second ring gear 32 is connected to the output shaft 12 together with the third carrier 48.
The third ring gear 42 can be fixed to the case 54 by the second brake 58.
The second carrier 38 can be connected to the third sun gear 40 by the third clutch 60 and the third ring gear 42 by the fourth clutch 62, and can be fixed to the case 54 by the lock mechanism 64. ing.

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 the engagement mechanism including the lock mechanism 64 is referred to as a fastening element.

  In the operation table of FIG. 2, 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 52, and ML represents the lock mechanism 64. And so on. The relationship between these symbols and the symbols of the respective fastening elements is shown in FIG.

In the vertical column of the operation table, “D range” and “R range” among the ranges such as “P”, “R”, “N”, “D”, and “L” of an operation lever (not shown) are taken up. The R range from forward 1st speed (1st) to 9th speed (9th) is assigned to each reverse speed.
In the operation table of FIG. 2, “o” represents the fastening of each fastening element, and the blank represents the release of each fastening element. The circles enclosed in parentheses indicate that they are fastened but not involved in power transmission.

  Here, the ratio of the number of teeth of each planetary gear set related to the gear ratio is expressed by α, the ratio (Zs / Zr) of the number of teeth (Zs) of the sun gear to the number of teeth (Zr) of the ring gear, and the first planetary gear. The group 14 will be described as α1, the second planetary gear group 16 as α2, and the third planetary gear group 18 as α3.

Here, the calculation of each gear ratio is illustrated for the case where the respective gear ratio is 0.27 for α1, 0.35 for α2, and 0.41 for α3.
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, as shown in the operation table shown in FIG. 2, the first forward speed (1st) is driven by the second clutch 56 (C-2), the third clutch 60 (C-3), and the second brake 58 ( It is performed by the conclusion of B-2). The subsequent engagement of the second brake 58 is maintained up to the fourth speed.
The speed ratio of the first speed is {α2 (1 + α1) (1 + α3) + α1} / {α2 · α3 (1 + α1)}, and the gear ratio set to the above value is 4.921.

Next, the shift to the second speed (2nd) is performed by releasing the engagement of the third clutch 60 at the first speed and engaging the first clutch 50 (C-1).
As described above, since the first planetary gear set 14 is united by engaging the first clutch 50, the input shaft 10 and the third sun gear 40 are directly connected.
The speed ratio of the second speed is (1 + α3) / α3, which is 3.439 in the above-described gear ratio.
In the second speed, the engagement of the second clutch 56 is not involved in the power transmission, but is maintained for the next shift.

Next, the shift to the third speed (3rd) is performed by releasing the engagement of the first clutch 50 at the second speed and engaging the first brake 52 (B-1).
The gear ratio is (1 + α3) / {α3 (1 + α1)}.
In the above-mentioned tooth number ratio, it is 2.708.

Next, the shift to the fourth speed (4th) is performed by releasing the engagement of the first brake 52 at the third speed and engaging the fourth clutch 62 (C-4).
The speed ratio of the fourth speed is {α3 (α2−α1) + α2} / {α2 · α3 (1 + α1)}. In the above-mentioned tooth number ratio, it is 2.100.

Next, the shift to the fifth speed (5th) is performed by releasing the engagement of the second clutch 56 and the second brake 58 at the fourth speed and engaging the first clutch 50 and the first brake 52. Is called.
The speed ratio of the fifth speed is {α2 (1 + α3) + α3} / {α3 (1 + α2)}. In the above-mentioned tooth number ratio, it is 1.632.

Next, the shift to the sixth speed (6th) is performed by releasing the engagement of the first clutch 50 at the fifth speed and engaging the second clutch 56 again.
The speed ratio of the sixth speed is {α3 (1 + α2) + α2} / {α3 (1 + α1) (1 + α2)}. In the above-mentioned tooth number ratio, it is 1.285.

Next, the shift to the seventh speed (7th) is performed by releasing the engagement of the first brake 52 and engaging the first clutch 50 at the sixth speed.
As a result, the entire planetary gear train is integrated, and the input shaft 10 and the output shaft 12 are directly connected, so the gear ratio of the seventh speed is 1 regardless of the gear ratio.

Next, in the shift to the eighth speed (8th), the third clutch 60 is also engaged at the seventh speed before the shift, and then the engagement of the second clutch 56 and the fourth clutch 62 is released, and then the first shift is performed again. This is done by fastening the brake 52.
The speed ratio of the eighth speed is 1 / (1 + α2), and the above gear ratio is 0.741.

Next, the shift to the ninth speed (9th) is performed by releasing the engagement of the first clutch 50 at the eighth speed and engaging the second clutch 56 again.
As a result, the transmission gear ratio becomes 1 / {(1 + α1) (1 + α2)}, and the above-mentioned gear ratio increases by 0.583.

Next, the reverse shift of the R range is performed by fastening the first clutch 50 and the second clutch 56 after the lock mechanism 64 is actuated by an actuator (not shown) to fix the second carrier 38 to the case 54. Is called.
As a result, the gear ratio becomes -1 / α2, and in the above-described gear ratio, -2.857.

When the lock mechanism 64 is operated, it is desirable that the second brake 58 and the fourth clutch 62 are fastened to stop the rotation of the second carrier 38 before the lock mechanism 64 is operated. In this way, even when the vehicle is moving at a slow speed, the lock mechanism 64 can be operated smoothly.
After the second carrier 38 is fixed to the case 54 by the lock mechanism 64, the engagement of the second brake 58 and the fourth clutch 62 is released, and the first clutch 50 and the second clutch 56 are engaged.
The lock mechanism 64 may be a general automatic transmission parking lock device or a dog clutch.

  Further, in order to perform the operation of the lock mechanism 64 more reliably and smoothly, in the neutral “N” range between the “D” range and the “R” range of an operation lever (not shown), the second brake 58 and the second brake 58 are operated. It is also useful to engage the 4 clutch 62 and stop the rotation of the second carrier 38. In this case, since the power transmission as the planetary gear train is not performed only by stopping the rotation of the second carrier 38, it is neutral.

The following is a list of the forward gear ratios described above. The value on the left is the gear ratio, and the value in the right parenthesis is the ratio between the gear ratio and the gear ratio one step higher (interstage ratio).
1st speed 4.921 (1.431)
Second speed 3.439 (1.270)
3rd speed 2.708 (1.289)
4th speed 2.100 (1.287)
5th Speed 1.632 (1.270)
6th speed 1.285 (1.285)
7th speed 1.000 (1.350)
8th speed 0.741 (1.270)
9th speed 0.583
From this, it can be seen that a gear ratio of 9 forward speeds, which is a preferable gear ratio for automobiles, can be obtained.

  As described above, the multi-stage planetary gear train according to the first embodiment of the present invention can achieve 9 forward speeds and 1 reverse speed in which a gear ratio preferable for an automobile can be obtained. In addition, since the gear train is configured as described above, a single pinion type having a simple structure, light weight and high power transmission efficiency can be used for the three planetary gear sets 14, 16, and 18, and in this case, The number of friction elements that are always idle is three, which is one less than that of the conventional example, so that drag resistance (drag torque) of the idle friction elements can be reduced.

Further, since the lock mechanism 64 is used as a means for fixing the second carrier 38 to the case 54 during reverse travel, drag resistance during forward travel is smaller than when a general friction clutch is used.
As a result, it is possible to obtain a 9-speed automatic transmission with excellent fuel efficiency and low heat generation.

FIG. 3 shows a skeleton diagram of the multi-stage planetary gear train according to the second embodiment of the present invention.
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 between the second embodiment and the first embodiment is that a one-way clutch (hereinafter referred to as “OWC”) 70 is provided in parallel with the third clutch 60.
The OWC 70 can transmit torque only in the direction in which the second carrier 38 drives the third sun gear 40 forward.
As a result, the torque for driving the output shaft 12 from the engine 1 at the first forward speed can be transmitted without engaging the third clutch 60.

Although the arrangement of the first clutch 50 and the second clutch 56 is slightly different from that of the first embodiment, the connection relationship is the same.
Since the rest of the configuration is the same as that of the first embodiment, detailed description thereof is omitted.

Next, the operation of the second embodiment will be described with reference to the operation table shown in FIG.
The difference from the operation table of the first embodiment shown in FIG. 2 is that the “L” range is described in addition to the “D” range, and the first speed of the D range is different from the first speed of the L range. is there.
That is, the first speed in the D range is automatically engaged only in the direction in which the OWC 70 accelerates the vehicle without engaging the third clutch 60.
Therefore, at the first speed in the D range, the input shaft 10 cannot be driven from the output shaft 12 side like so-called engine braking.

  Since the first speed drive is performed when the OWC 70 is engaged, it is only necessary to add the engagement of the first clutch 50 in the shift from the first speed to the second speed. At this time, the engagement of the OWC 70 is automatically released. The

Since the first speed of the L range engages the third clutch 60 in the same manner as the first speed of the D range in the first embodiment, the input shaft 10 can be driven from the output shaft 12 side.
Since other operations are the same as those in the first embodiment, detailed description thereof is omitted.

  Similarly to the first embodiment, the multi-stage planetary gear train according to the second embodiment of the present invention can obtain a preferable gear ratio for the automobile in the ninth forward speed and the first reverse speed, and the gear train is configured as described above. The planetary gear sets 14, 16, and 18 can be a single pinion type having a simple structure, light weight, and high power transmission efficiency. In this case, the number of friction elements that are always idle is three, which is one less than the conventional example, so that drag resistance (drag torque) of the idle friction elements can be reduced.

FIG. 5 shows a skeleton diagram of a multi-stage planetary gear train according to the third embodiment of the present invention.
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 between the third embodiment and the first embodiment is that the engine 1 is disposed on the right side and that the output shaft 12 is disposed outside the input shaft 10, and the output shaft 12 is connected to the output gear 12a. It is united.
The output gear 12a drives a wheel via a counter gear (not shown).
Since other parts are the same as those of the first embodiment, detailed description thereof is omitted.

Next, the operation of the third embodiment will be described.
The operation of the third embodiment is the same as that of the first embodiment, and the operation table is also the same as that shown in FIG.

Similarly to the first embodiment, the multi-stage planetary gear train according to the third embodiment of the present invention can obtain a preferable gear ratio for the vehicle in the ninth forward speed and the first reverse speed, and the gear train is configured as described above. The planetary gear sets 14, 16, and 18 can be a single pinion type having a simple structure, light weight, and high power transmission efficiency. In this case, the number of friction elements that are always idle is three, which is one less than the conventional example, so that drag resistance (drag torque) of the idle friction elements can be reduced.
Further, since the output shaft 12 is disposed outside the input shaft 10 and integrated with the output gear 12a, a layout suitable for a front wheel drive vehicle is possible.

  As described above, the multi-stage planetary gear train according to each embodiment of the present invention can obtain a transmission gear ratio of 9 forwards that is preferable for an automobile, and can provide an automatic transmission that is excellent in fuel efficiency and generates less heat. Become.

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, the example in which the lock mechanism 64 is used as a means for fixing the second carrier 38 to the case 54 during reverse travel has been described, but a general multi-plate friction clutch, conical clutch, or the like can also be used.

  Since it is possible to obtain an automatic transmission that has a forward gear ratio exceeding eight forward speeds, excellent fuel efficiency, and generates little heat, it can be widely applied to small passenger cars that emphasize fuel efficiency to medium-sized commercial vehicles.

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. It is the skeleton figure which showed the multi-stage planetary gear train of this invention. (Example 3)

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 10 Input shaft 12 Output shaft 14 1st planetary gear set 16 2nd planetary gear set 18 3rd planetary gear set 20 1st sun gear 22 1st ring gear 24 1st pinion 28 1st carrier 30 2nd sun gear 32 2nd ring gear 34 2nd pinion 38 2nd carrier 40 3rd sun gear 42 3rd ring gear 44 3rd pinion 48 3rd carrier 50 1st clutch 52 1st brake 54 Case 56 2nd clutch 58 2nd brake 60 3rd clutch 62 Fourth clutch 64 Lock mechanism 70 One-way clutch (OWC)

Claims (3)

An input shaft;
An output shaft;
The first sun gear, the first ring gear, the first ring gear, a first pinion meshing with the first sun gear, and a first carrier that rotatably supports the first pinion are arranged coaxially with the input shaft. A first planetary gear set;
The second sun gear, the second ring gear, the second ring gear, the second pinion meshed with the second sun gear, and the second carrier that rotatably supports the second pinion are disposed coaxially with the output shaft. A second planetary gear set;
A third sun gear, a third ring gear, a third pinion meshing with the third ring gear, and a third carrier that rotatably supports the third pinion are arranged coaxially with the output shaft. A third planetary gear set,
The input shaft is connected to the first carrier;
The output shaft is connected to the second ring gear and the third carrier;
The first sun gear is connectable to the second sun gear;
The first ring gear is connected to the third sun gear;
The second sun gear can be fixed to a stationary part,
The second carrier can be connected to the third sun gear and the third ring gear, respectively, and can be fixed to the stationary part without being connected to the third ring gear,
The third ring gear can be fixed to the stationary part,
The first planetary gear set can be integrated by a clutch.   The multi-speed planetary gear train according to claim 1, wherein the means for fixing the second carrier to the stationary portion is a lock mechanism.   2. The multi-speed planetary gear according to claim 1, wherein the second carrier and the third sun gear are connectable by a friction clutch and are connected by a one-way clutch arranged in parallel with the friction clutch. Column.

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