JPH0621619B2 - Planetary gear train for automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a so-called Ravigneaux planetary gear train having a single-row planetary gear and a double-rowed planetary gear that share one planet carrier.

(Prior Art and Problems Thereof) A conventional Ravigneaux type planetary gear train of this type is constructed as shown in FIG.

That is, 10 is a planetary gear that is relatively long in the axial direction,
It forms a single-row planetary gear by meshing with the sun gear 16.
Further, the planetary gear 10 is held by the planetary carrier 14, and the planetary gear 12 is mounted on the planetary carrier 14.
The planetary gear 12 meshes with the sun gear 18 to form a double-row planetary gear. Further, the planet carrier 14 is connected to the output gear 22.

Brake B1, B2, B3 for controlling each of these gears,
The clutches C1 and C2 are provided, and each brake and clutch is turned on (marked with a circle) as shown in Table 1 below.
Shifts forward 4th speed and reverse 1st speed.

In the case of the third forward speed, the brake B3 is deleted.

By the way, in recent years, in order to improve the indexing force performance, the shift speed is being changed to another gear from the third forward speed to the fourth forward speed and further to the fifth forward speed.

However, in the conventional planetary gear train, the number of clutches increases as the number of gears increases, and the structure and control become complicated.

If the stall torque ratio is increased in order to solve this problem with a normal three-element one-stage torque converter, the following problem occurs.

(1) Since the capacity of the torque converter decreases, the size of the torque converter must be increased.

(2) Efficiency decreases near the coupling point of the torque converter.

(3) The practical limit of the stall torque ratio is about 3.

Therefore, the present inventor devised the present invention in a four-element torque converter, in an attempt to solve the above problems by weighting and outputting a reversing force from a reversing stator to a conventional Ravigneaux planetary gear train. Came to do.

(Object of the Invention) The present invention has an indexing force performance at 1st speed which is the number of starting stages and
By improving the indexing force performance obtained in the high speed and fourth speed regions, it is an object of the present invention to reduce the number of shift speeds by one gear from the conventional one and simplify the structure and control.

(Structure of the Invention) (1) Technical Means According to the present invention, a single-row planetary gear and a double-row planetary gear that share a single planet carrier are provided downstream of a four-element torque converter including two stators, a turbine, and a pump. In an automatic transmission having a Ravigneaux planetary gear train having
A single ring gear is provided only on the outer circumference of the single-row planetary gear, a turbine shaft is connected to connect the sun gear of the turbine single-row planetary gear, and a stator cylinder shaft is connected to connect the first stator and the sun gear of the double-row planetary gear. A brake that restricts the rotation of the stator cylinder shaft, and a clutch that restricts the rotation of the ring gear of the single-row planetary gear by providing a clutch between the stator cylinder shaft and the turbine shaft or between the sun gear and the turbine shaft of the single-row planetary gear. And a brake for restricting rotation of the turbine shaft so that power is output from an output gear connected to the planet carrier, and the planetary gears of the automatic transmission are set to the third or fourth forward speed and the first reverse speed. It is a gear train.

(2) Action In the first speed, the reverse rotation force of the first stator is input to the double-row planetary gear and weighted on the turbine output.

In the second speed and the fourth speed, the first stator is fixed, and the first stator idles in the speed ratio range before the second stator idles, so that high efficiency is obtained.

In reverse, the turbine is fixed and the reverse rotation force of the first stator is output.

(Embodiment) (1) First Embodiment An automatic transmission of three forward speeds and one reverse speed for a front-wheel drive passenger vehicle adopting the present invention will be described with reference to FIG. In FIG. 1, the parts given the same reference numerals as in FIG. 3 indicate the same or corresponding parts.

In FIG. 1, reference numeral 30 is a four-element two-stage torque converter, and the torque converter 30 includes a pump 32 and a turbine 3.
4, a first stator 36, a second stator 38 and the like.

The turbine 34 is connected to the turbine shaft 40, and the first stator 36 is connected to the stator cylinder shaft 4 via the one-way clutch 42.
It is connected to 4. The stator cylinder shaft 44 is the turbine shaft 40.
Are arranged concentrically with respect to each other. In the one-way clutch 42, the first stator 36 is the turbine 3
When the first stator 36 rotates in the same direction as the first stator 36, that is, when the first stator 36 rotates in the forward direction, the first stator 36 is locked and the reverse rotation force of the first stator 36 is transmitted to the stator cylinder shaft 44. The second stator 38 is the one-way clutch 4.
It is connected to the fixed cylinder shaft 48 via 6. Fixed cylinder shaft 4
Numeral 8 is provided concentrically outside the stator cylinder shaft 44 in the radial direction. The fixed cylinder shaft 48 is continuous with the housing 50. Further, the turbine 34 is provided with a lockup clutch 52.

An automatic transmission is configured by combining a so-called Ravigneaux type planetary gear train, which will be described later in detail, in the latter stage of the torque converter 30.

The turbine shaft 40 is connected to the sun gear 16 (the number of teeth: Za2), and a brake B3 is provided at the rear end of the turbine shaft 40. Ring gear 20 meshing with planet gear 10
A brake B2 is provided at (number of teeth: Zr2).

Further, the stator cylinder shaft 44 is connected to the sun gear 18 (the number of teeth: Za1), and a brake B1 is provided at an intermediate portion of the stator cylinder shaft 44. The stator cylinder shaft 44 and the turbine shaft 4
A clutch C1 is interposed between 0s.

The planet carrier 14 is connected to the output gear 22 and
Power is output from 2.

Next, the operation of the automatic transmission shown in FIG. 1 will be described. In the planetary gear train as described above, the brakes B1 to B3 and the clutch C1 are selectively turned on (fixed) as shown in Table 2 which will be described in detail later to perform the third forward speed and the first reverse speed.

At the first speed when only the brake B2 is ON, the reverse rotation force of the first stator 36 is applied from the stator cylinder shaft 44 to the sun gear 1.
8, the forward rotation force of the turbine 34 transmitted from the turbine shaft 40 to the sun gear 16 through the planetary gear 10 is applied to the forward rotation force of the first stator 36 through the planetary gear 12,
The efficiency and the torque ratio are improved in the region where the first stator 36 generates the reverse rotation force.

That is, as shown in FIG. 1a showing changes in the torque ratio t and the efficiency η with respect to the speed ratio e, in the range of P or less where the rotation direction of the first stator 36 changes to normal rotation, the efficiency is lower than the conventional efficiency characteristic η0. The torque ratio is the torque ratio characteristic t
The torque ratio characteristic t1 is improved from 0. It should be noted that in the range above the point P, the first stator 36 runs idle due to the action of the one-way clutch 42.

Next, in the second speed in which only the brake B1 is ON, the first
In the speed ratio range until the stator 36 idles, the first stator 3
6 is locked, and the power transmitted from the turbine 34 is increased.
Also, in the speed ratio range before the second stator 38 idles,
Since the stator 36 idles, the loss due to the fluid in the stator portion is reduced, and the efficiency can be improved in the speed ratio range.

In this second speed range, as shown in FIG. 1b, the efficiency characteristic η
The efficiency characteristic η2 can be improved from 0, and the torque ratio characteristic t0 can be improved from the torque ratio characteristic t0.

Further, in the third speed in which only the clutch C1 is in the ON operation, the first
The efficiency characteristic η3 and the torque ratio characteristic t3 shown in FIG.

Finally, when the brake B3 is turned on in reverse, the turbine 34 is fixed, and only the reverse rotation force from the first stator 36 is transmitted from the sun gear 18 to the planetary gear 10 and the planetary gear 12 through the fixed sun gear 16 as a reaction force. The ring gear 20 and the output gear 22 are reversed. During this reverse movement, the efficiency characteristic ηR and the torque ratio characteristic tR are exhibited as shown in FIG. 1d.

(2) Second Embodiment In FIG. 2 showing the second embodiment, a clutch C1 is provided between the sun gear 16 and the turbine shaft 40, and a clutch C2 is provided between the ring gear 20 and the turbine shaft 40. Each of these brakes and clutches is turned on as shown in the following Table 2 to perform the fourth forward speed and the first reverse speed.

When the brakes and clutches are operated as shown in Table 2, the gear ratios of the turbine 34 and the first stator 36 are as shown in Table 2. At this time, if the number of teeth of the sun gear 16, 18 and the ring gear 20 are set to Za1 = 21, Za2 = 72, Zr1 = 36 (1), the gear ratio of the turbine 34 at the first speed is 3.
000, the gear ratio of the first stator 36 is -2.429, the turbine 34 is 1.583 in the second speed, the turbine 34 is 1 in the third speed, and the turbine 34 is 0.70 in the fourth speed.
8, the first stator 36 becomes 2.714 in reverse.

(Effects of the Invention) As described above, the planetary gear train of the automatic transmission according to the present invention has the following effects.

At the first speed, the reverse rotation force of the first stator 36 is transmitted from the stator cylinder shaft 44 to the sun gear 18, and is transmitted from the turbine shaft 40 to the sun gear 16 through the planetary gear 10.
4 through the planetary gear 12 to the first stator 36
It is possible to improve the efficiency and the torque ratio in the region where the first stator 36 rotates in the reverse direction by weighting the reverse rotation force.

Therefore, as shown in FIG. 1a, the efficiency is changed from the conventional efficiency characteristic η0 to the efficiency characteristic η1 and the torque ratio is changed from the torque ratio characteristic t0 to the torque within a range below the point P at which the rotation direction of the first stator 36 is changed to normal rotation. The specific characteristics t1 can be improved.

Next, in the second speed in which only the brake B1 is ON, the first
In the speed ratio range until the stator 36 idles, the first stator 3
6 is locked, and the power transmitted from the turbine 34 is increased.
Also, in the speed ratio range before the second stator 38 idles,
Since the stator 36 idles, the loss due to the fluid in the stator portion is reduced, and the efficiency can be improved in the speed ratio range.

As shown in FIG. 1b, the efficiency characteristic η0 to the efficiency characteristic η2
In addition, the torque ratio characteristic t0 can be improved to the torque ratio characteristic t2, and a high torque ratio and high efficiency can be exhibited. Since the embodiment shown in FIG. 2 can obtain the effect shown in FIG. 1b at the fourth speed, in the present invention, the conventional fourth forward speed is the third forward speed and the fifth forward speed is the fourth forward speed. The same indexing force characteristics can be obtained with the number of stages. Therefore, compared with the conventional automatic transmission, the guide vanes of the torque converter are
The number of gears is increased by one by simply increasing the number of gears and connecting it to the sun gear, and the structure and control are simplified.

In this way, the torque ratio and efficiency are improved in the first speed, the second speed, and the fourth speed.

Moreover, in the case of FIG. 1, the structure is complicated, and only one clutch having a long axial dimension is provided, so that the entire automatic transmission becomes compact.

[Brief description of drawings]

FIG. 1 is a structural schematic diagram showing a first embodiment according to the present invention.
FIG. a is a graph showing changes in torque ratio and efficiency with respect to speed ratio in the first speed, FIG. 1b is the same graph in second speed and fourth speed, and FIG. 1c is the same graph in third speed. FIG. 1d is the same graph in reverse, FIG. 2 is a structural schematic diagram showing a second embodiment according to the present invention, and FIG. 3 is a structural schematic diagram showing a conventional example. 10 ... Single-row planetary gear, 12 ... Double-row planetary gear, 14 ...
… Planetary carrier, 18, 18 …… Sangya, 20 …… Ring gear, 22 …… Output gear, 30 …… Torque converter

Claims (1)

[Claims] 1. A stator (36, 38) and a turbine (3).
4), a single-row planetary gear (1) sharing one planetary carrier (14) after the four-element torque converter consisting of the pump (32)
0) and a Ravigneaux planetary gear train having a double-row planetary gear (12), in an automatic transmission, one ring gear (20) is provided only on the outer periphery of the single-row planetary gear (10), and the turbine (34) And the turbine shaft connecting the single row planetary gear (10) and the sun gear (16)
(40) is provided, and a stator cylinder shaft (44) that connects the first stator (36) and the sun gear (18) of the double-row planetary gear (12) is provided, and a brake that restricts rotation of the stator cylinder shaft (44) Provide (B1),
A clutch (C1) is provided between the stator cylinder shaft (44) and the turbine shaft (40) or between the sun gear (16) and the turbine shaft (40) of the single-row planetary gear (10) to provide the single-row planetary gear (10). ) Ringga (20)
Equipped with a brake (B2) that controls the rotation of the turbine shaft (40)
A brake (B3) for restricting the rotation of the vehicle is provided, power is output from the output gear (22) connected to the planet carrier (14), and the third forward speed or the fourth speed stage and the reverse first speed stage are set. A planetary gear train of an automatic transmission characterized by.