KR100244941B1 - 4 speed automatic transmission - Google Patents

Abstract

An object of the present invention is to connect each gear element so as to have only a variable connection structure without the fixed connection structure to the gear train consisting of two sets of single pinion planetary gear mechanism and double pinion planetary gear mechanism 4 stages and R stage (including three stages) It is to provide a four-speed automatic transmission in which the rotational speed of the entire element of the planetary gear mechanism rotates at the output speed during shifting, thereby reducing the power loss and reducing the frictional loss due to the arrangement characteristics of the other friction elements.

Means of the present invention for achieving the above object comprises a single pinion planetary gear mechanism (hereinafter referred to as a first gear mechanism) to which the input shaft is connected and a double pinion planetary gear mechanism (hereinafter referred to as a second gear mechanism) to which the output shaft is connected. A four-speed automatic transmission comprising: an input shaft connected to a sun gear of the first gear mechanism, a first clutch for selectively connecting a carrier of the first gear mechanism and a ring gear of the second gear mechanism, and the first gear mechanism. A second clutch for selectively connecting a ring gear of the first gear mechanism and a sun gear of the second gear mechanism, a third clutch for selectively connecting two elements selected from the ring gear, the carrier and the sun gear of the first gear mechanism; A first brake for stopping rotation of the ring gear of the second gear mechanism, a second brake for stopping rotation of the sun gear of the second gear mechanism, and a carrier of the second gear mechanism. Which it is characterized in that it is formed with an output shaft, and.

Description

4-speed automatic transmission

1 is a system diagram showing a first embodiment of a four-speed automatic transmission according to the present invention.

2 is a system diagram showing a second embodiment of a four-speed automatic transmission according to the present invention.

3 is a system diagram showing a third embodiment of a four-speed automatic transmission according to the present invention.

<Explanation of symbols for main parts of drawing>

PG ₁ : Single pinion planetary gear mechanism (first gear mechanism)

PG ₂ : Double pinion planetary gear mechanism (second gear mechanism)

1: Input shaft 2: First sun gear

3: first pinion gear 4: first carrier

5: 1st ring gear 6: 2nd sun gear

7: 2nd pinion gear (double type) 8: 2nd carrier

9: second ring gear 10, 11, 12: connecting member

13: output shaft B ₁ , B ₂ : brake

C ₁ , C ₂ , C ₃ : Clutch

[Industrial use]

The present invention constitutes a gear train with an automatic transmission, in particular a single pinion planetary gear mechanism connected to an input shaft and a double pinion planetary gear mechanism connected to an output shaft, and adopts only a variable connection structure without omitting a fixed connection structure between the gears. It only relates to a four-speed automatic transmission with one reverse gear.

[Private Technology]

As is well known, the transmission serves to increase or decrease the rotational force of the engine according to the change of the driving state of the vehicle, and also has a reverse device for reversing the vehicle. As a device for enabling this, a planetary gear mechanism is used.

The planetary gear mechanism has three elements, a sun gear and a ring gear, and a carrier for preserving the pinion gears engaged with the gears. The planetary gear mechanism fixes one element as an input element and another as an output element. Therefore, it is possible to increase or decelerate the input rotation or reversely decelerate and output the gear. Usually, only one planetary gear mechanism makes it difficult to obtain a desired gear stage. It consists. In this case, the gear ratio of the planetary gear mechanism, the gear ratio of the planetary gear mechanism, and the single pinion type planetary gear mechanism or the double pinion type planetary gear mechanism and the friction factors controlling them vary. However, not all combinations of them can be used practically, but are limited to the use of a gear train having practical feasibility that satisfies all conditions such as mounting on a vehicle, manufacturability, shift characteristics, and required power performance.

However, since such a gear train can be composed of a large number by the combination of the planetary gear mechanism and the gear ratio setting method, it is a very difficult task to find a product that satisfies the requirements for an automatic transmission for a vehicle.

Conventionally, a number of gear transmissions have been proposed under such a background. Among them, a four-speed automatic transmission is based on a three-speed automatic transmission composed of two planetary gear mechanisms, and an overdrive drive mechanism or an underbody planetary gear mechanism. By installing a driver mechanism, the gearbox has achieved 4 forward speeds.

However, in recent years, the automatic transmission used by the front engine and high horsepower is required to be further downsized, and the transmission torque capacity is also increased. With a four-speed automatic transmission, it is difficult to meet the requirements.

Therefore, based on the planetary gear mechanism and the Ravigneaux type of the Simpson type (Simpson type, US Patent No. 2,873,621), which is the original support for the automatic transmission, which has been used conventionally, it is modified little by little to meet the requirements. As an example, an automatic transmission that obtains four speeds by adding two clutches is proposed in Japanese Patent Laid-Open No. 59-183147.

The automatic transmission mechanism interposes a third clutch between the sun gear of the first planetary gear mechanism and the sun gear of the second planetary gear mechanism that is integrally connected in the conventional Simpson method, and at the same time, the sun gear of the first planetary gear mechanism. And the carrier of the second planetary gear mechanism are connected through the fourth clutch, the third clutch is released to separate the first planetary gear mechanism and the second planetary gear mechanism, and the fourth clutch is connected to the second planetary gear. While inputting to the carrier of the gear mechanism, the sun gear of the second planetary gear mechanism is fixed to output the overdrive from the ring gear, and the fourth speed is obtained in addition to the conventional three speeds.

Other four-speed automatic transmissions include Japanese Patent Publication No. 61-19866, Japanese Patent Publication No. 61-37493, Japanese Patent Publication No. 61-37494, and US Patent No. 4369672.

Among them, the automatic transmission described in Japanese Patent Laid-Open No. 61-19866 includes two single pinion planetary gear trains and one double pinion planetary gear train and the planetary gearbox. It consists of two clutches and three brakes for controlling the gear mechanism.

On the other hand, the automatic transmission device disclosed in Japanese Patent Laid-Open Publication No. 3-74658 includes three sets of single-pinion type planetary gear mechanisms and the ring gear of the first planetary gear mechanism and the carrier of the second planetary gear mechanism are always connected or engaged. The carrier of the first planetary gear mechanism and the ring gear of the third planetary gear mechanism are selectively connected via means, and are selectively connected through the constant connection or engagement means, and the sun gear and the third planetary gear of the first planetary gear mechanism are also selectively connected. The sun gear of the mechanism is selectively connected via always-connecting or engaging means. In addition, the ring gear of the first planetary gear mechanism and the carrier of the second planetary gear mechanism are integrally or individually with each other, and the carrier of the first planetary gear mechanism and the ring gear of the third planetary gear mechanism are integrally or individually with each other. The sun gear of the planetary gear mechanism and the carrier of the third planetary gear mechanism are integrally or individually with each other, and the sun gear of the second planetary gear mechanism and the sun gear of the third planetary gear mechanism are integrally or individually with each other. Element and the independent element such as the ring gear of the second planetary gear mechanism becomes the input element or the output element or the fixed element, so that each planetary gear mechanism increases or decreases integrally or individually and shifts the rotation of the input shaft. It is transmitted as it is or inverted to the output shaft.

[Problems with Prior Art]

However, in the case of many conventional automatic transmission devices, the structures thereof are not only too complicated, but the rotation speed of the output shaft becomes higher than that of the input shaft. In addition, there is a problem that the loss is large due to the existence of the gear of the planetary gear mechanism that rotates at a high speed even at a relatively high speed compared to the output rotation speed, and also due to the sliding of friction elements such as clutches and brakes that control the planet gear mechanism. There is a problem that the power loss is high.

On the other hand, the presence of an element with a higher rotational speed than the number of rotations on the input and output side causes noise, and also causes problems such as power loss and temperature rise due to the resistance of the transmission oil.

[Problem of invention]

Therefore, the present invention has been proposed in view of the above problems, and its purpose is to adopt two variable planetary gear mechanisms and omit fixed connection structure. It is to provide a four-speed automatic transmission that reduces the power loss by allowing the speed of the entire element to rotate below the output rotation speed. In particular, all the elements of the first gear mechanism rotate at the input rotation speed at four speed and R speed. .

Another object of the present invention is a four-speed automatic transmission that minimizes sliding power loss of each friction element by properly arranging the clutch friction elements used for shift control to selectively connect the respective gears between the planetary gear mechanisms. To provide.

Another object of the present invention to provide a four-speed automatic transmission of the structure that can reduce the noise generation.

[Means for solving the problem]

The present invention provides a single pinion planetary gear mechanism (hereinafter referred to as a first gear mechanism) to which an input shaft is connected and a double pinion planetary gear mechanism (hereinafter referred to as a second gear mechanism) to achieve the above object as described in claim 1. And a first clutch for selectively connecting an input shaft connected to the sun gear of the first gear mechanism and a carrier and a ring gear of the first and second gear mechanisms. And a second clutch for selectively connecting the ring gear of the first gear mechanism and the sun gear of the second gear mechanism, and selectively connecting two elements selected from the ring gear, the sun gear and the carrier of the first gear mechanism. A third clutch, a first brake for stopping rotation of the ring gear of the second gear mechanism, a second brake for stopping rotation of the sun gear of the second gear mechanism, An output shaft directly connected to the carrier of the second gear mechanism, and a four-speed automatic transmission characterized in that is characterized by.

According to the second aspect of the present invention, the first genus is obtained by combining only the first clutch, the second clutch, and the first brake, and the second genus is maintained while the first clutch and the second clutch are coupled to each other. The first brake is released and the second brake is engaged. The third speed is obtained by releasing the first and second brakes while the first, second and third clutches are engaged. The fourth speed is the second speed. It is obtained by combining the first, third clutch and the second brake in a state in which the clutch and the first brake are released, and the reverse (speed R) is the second and the second in the state in which the first clutch and the second brake are released. The three-speed clutch and the first brake are combined to obtain a gear shift stage.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[First Embodiment]

1 is a skeleton diagram showing an embodiment of the automatic transmission of the present invention for achieving a shift stage of four forward reverse stages, and one end of the input shaft 1 is connected to a torque converter, not shown, and the other end thereof. It is connected to the first sun gear 2 of the single pinion planetary gear mechanism PG ₁ , hereinafter simply referred to as the first gear mechanism PG ₁ .

The first gear mechanism PG ₁ supports the first sun gear 2, the first pinion gear 3 engaged with the first sun gear 2, and the first pinion gear 3 in a freely rotating manner. Double pinion planetary gear which is composed of a first carrier 4 rotatable and the first ring gear 5 engaged with the first pinion gear 3 and arranged in parallel with the first gear mechanism PG ₁ . The mechanism PG ₂ (hereinafter referred to simply as the second gear mechanism PG ₂ ) refers to the second sun gear 6 and the second double pinion gear 7, which is engaged with the sun gear 6, having two pinion gears. A first pinion gear or simply a pinion gear), a second carrier 8 rotatably supporting the second pinion gear 7 and a second pinion gear 7 rotatable therewith; It consists of two ring gears (9).

Both carriers 4 and ring gears 9 of the first and second gear mechanisms PG ₁ and PG ₂ are connected by a connecting member 10 via a first clutch C ₁ . When the first clutch C ₁ is coupled, both side carriers 4 and the ring gear 9 become fixed connection means to rotate together together and are driven separately when separated.

Both ring gears 5 and the sun gear 6 of the first and second gear mechanisms PG ₁ and PG ₂ are connected by a connecting member 11 via a second clutch C ₂ . In the state in which the second clutch C ₂ is engaged, both ring gears 5 and the sun gears 6 also rotate in the same direction at the same time as the same elements, and in the disengaged state, they rotate individually.

In addition, the first ring gear 5 and the first carrier 4 of the first gear mechanism PG ₁ are connected by the connecting member 12 via the third clutch C ₃ to connect the third clutch ( ₃ ). When C ₃ ) is combined, the first ring gear 5 and the first carrier 4 are integrally formed so that the first gear mechanism PG ₁ , in which two elements are connected as one, rotates as a whole. .

An output shaft 13 is connected to the second carrier 8, and a second brake B ₂ is formed between the casing and the second ring gear in the second sun gear 6 to stop its rotation. a first brake (B ₁₎ for stopping the rotation of the camshaft 9 is provided between the casing.

Accordingly, the first and second clutches C ₁ and C ₂ selectively connect the carriers 4 and the ring gears 9, the ring gears 5 and the sun gears 6 on both sides thereof (that is, the variable connection structure). In particular, the third clutch C ₃ is provided to selectively connect the carrier 4 and the ring gear 5 of the first gear mechanism so that the entire first gear mechanism PG ₁ may be provided. Rotates into one, which forms one of the important features for achieving the object of the present invention.

The automatic transmission device of FIG. 1 has a first speed stage according to engagement and release of the three clutches C ₁ , C ₂ , C ₃ and the two brakes B ₁ , B ₂ as summarized in Table 1. , Second speed stage, third speed stage (direct drive stage), fourth speed stage (overdrive stage) and reverse (R) are obtained.

In this table, 0 indicates that the clutch or brake is engaged (operated) while the engine is running, and blanks are released (disengaged).

Hereinafter, five shifts of the fourth forward speed and the first reverse speed will be described with reference to Table 1 below.

[1st speed stage]

In the transmission, the first clutch C ₁ and the second clutch C ₂ are changed from neutral to the first speed stage by a coupling state. The second ring gear 9 and the first brake (B _1), rotation is stopped at the same time the first clutch (C ₁₎ a first carrier (4) by the coupling is stopped with the second clutch (C ₂₎ by By combining the first ring gear 5 and the second sun gear 6 is driven at the same speed. Accordingly, the rotation of the input shaft 1 rotates at the same speed as the first sun gear 2, the first pinion gear 3 rotating, the first ring gear 5 driven, and the first ring gear 5 rotating. It is transmitted to the output shaft 13 through the sun gear 6 and the second carrier 8 to obtain a reduced speed ratio.

[Second speed stage]

In the transmission, the first clutch C ₁ and the second clutch C ₂ are additionally engaged with the second brake B ₂ by the engaged state, and the first brake B ₁ is released to release the first speed stage. To change to the second speed stage.

When the second brake B ₂ is actuated, the second sun gear 6 is braked with respect to the casing, so the rotation is stopped. At the same time, the rotation of the first ring gear is also stopped by the engagement of the second clutch C ₂ . The first carrier 4 and the second ring gear 9 are integrally rotated by the clutch by 1: 1. Accordingly, the rotation of the input shaft 1 is transmitted to the output shaft 13 through the first carrier, the second ring gear rotating at the same rotational speed as the first carrier, and the second carrier to reduce the output gear ratio and output the first gear. Higher speed output than speed stage is obtained.

[3rd speed stage]

The transmission maintains engagement of the first and second clutches C ₁ and C ₂ while releasing the second brake B ₂ and engaging the third clutch C ₃ . It is changed to 3 speed stages.

When the first, second and third clutches C ₁ , C ₂ and C ₃ are coupled, the first carrier 4 and the second ring gear 9 are connected, and the ring gear 5 and the carrier are connected. Not only (4) is connected but also both ring gear 5 and sun gear 6 are connected at the same time, the first carrier, the first ring gear, the second sun gear, and the second ring gear all rotate at the same speed. Accordingly, the first gear mechanism PG ₁ and the second gear mechanism PG ₂ are in a direct driving state, and the speed ratio becomes 1: 1 with the same input and output rotation speeds, and the entire element rotates at the input rotation speed.

[4th speed stage]

The transmission is engaged from the third speed stage to the fourth speed stage, ie overdrive, by releasing the second clutch C ₂ and engaging the second brake B ₂ while the first and third clutches remain engaged. It will change to a step.

When the second brake B ₂ is engaged, the sun gear 6 is braked with respect to the casing to stop rotation, and the carrier 4 and the ring gear 5 of the first gear mechanism PG ₁ are connected to the third clutch C _3. The first gear mechanism PG ₁ rotates at the input rotational speed and the second carrier is driven by the second ring gear 9 rotating at the same speed by the first clutch coupling. Since (8) is driven and speeded up, the output speed is increased compared to the input speed. Therefore, no element rotates faster than the input speed except for the second carrier.

[Reverse step]

The transmission is changed from the neutral to the reversed stage by combining the second clutch C ₂ , the third clutch C ₃ , and the first brake B ₁ and releasing the rest.

The rotation of the second ring gear 9 is stopped by the first brake B ₁ , and the first carrier, the first ring gear, and the second sun gear are rotated at the same speed by the connection of the second clutch and the third clutch. . Accordingly, the first gear mechanism as a whole rotates at the input rotational speed, thereby reversing the second carrier through the second sun gear having the same speed, and the speed is decelerated.

Table 2 shows the power loss rates of the friction elements of an automatic transmission with two brake elements and three clutch elements, which are the conventional four-speed (four forward and one reverse) transmissions, including the Simpson type and Lavigno type. Slip loss) (specific model to be compared is Hyundai Motor Co., Ltd. A4BF1 transmission) Table 3 shows the power loss rate of each friction element of the present invention having the same conditions.

The gear ratios of the two sides to be compared were used as 2.846 in the first stage, 1.581 in the second stage, 0.685 in the first and fourth stages, and 0.685 in the fourth stage.

Since the method of calculating the power loss rate due to the sliding of the friction elements is well known, a description of the calculation formula is omitted here and only the results are compared.

As shown in the above table, the power loss according to the present invention is 43% of A4BF1, which is a comparison model at 1 speed and 2 speed, 60% at 4 speed, and 46% at backward, so it is about 55% overall. Rather, the power loss (loss due to the sliding of friction elements) is reduced by about 45%.

Second Embodiment

2 is a view showing another embodiment of the present invention, in which the third clutch C ₃ selectively connects the first carrier 4 and the first ring gear 5 in the first embodiment (both elements are combined or Or separation), in the present embodiment, there is a difference between selectively connecting, ie, combining or releasing the first carrier 4 and the first sun gear 2, and the operation table and the 3rd, 4th speed, It is the same that all the elements 2, ₄ and 5 of the first gear mechanism PG ₁ rotate at the same speed at R speed.

Table 4 below is a chart showing the power loss due to the sliding of the friction elements of the embodiment.

As described above, the power loss due to the sliding of the friction element of this embodiment is 50% at 1st speed and 2nd speed, 60% at 4th speed and 46% at R speed, and the total is 58% level compared to the result of A4BF1. It can be seen that friction loss is reduced by about 42%.

Third Embodiment

3 is a view showing a third embodiment of the present invention. The third clutch C ₃ is configured to selectively engage or separate the first sun gear 2 and the first ring gear 5. And the rotation of the entire element at or below the output speed in R speed (including the third speed) is also the same as in the previous embodiments.

Table 5 shows the power loss due to the sliding of the friction elements of the embodiment.

[effect]

According to the present invention as described above, the first carrier, the second ring gear, the first ring gear and the second sun gear of the first gear mechanism (single-pinion planetary gear mechanism) and the second gear mechanism (double pinion planetary gear mechanism) It is possible to selectively engage or disengage as a friction element by the clutch, and in particular, by providing a clutch that selectively connects the carrier of the first gear mechanism and two elements selected from ring gear and sun gear. As all the elements of the 1 gear mechanism rotate at the input speed and the other elements rotate within the output speed, the transmission has a conventional single pinion + double pinion planetary gear mechanism and five friction elements (clutch 3, brake 2). Compared to this, the loss is greatly reduced and the slip loss is reduced and the noise is reduced according to the arrangement characteristics of the friction elements.

Claims (2)

A four-speed automatic transmission comprising a single pinion planetary gear mechanism (hereinafter referred to as a first gear mechanism) to which an input shaft is connected and a double pinion planetary gear mechanism (hereinafter referred to as a second gear mechanism) to which an output shaft is connected, wherein the first gear mechanism An input shaft connected to the sun gear of the first gear mechanism, a first clutch for selectively connecting the carrier of the first gear mechanism and the ring gear of the second gear mechanism, the ring gear of the first gear mechanism and the sun gear of the second gear mechanism; A second clutch connected to each other, a third clutch selectively connecting two elements selected from the ring gear, the carrier and the sun gear of the first gear mechanism, and for stopping the rotation of the ring gear of the second gear mechanism. And a first brake, a second brake for stopping rotation of the sun gear of the second gear mechanism, an output shaft directly connected to the carrier of the second gear mechanism, and 4 speed automatic transmission. The method of claim 1, wherein the first speed is obtained by combining only the first clutch, the second clutch, and the first brake, and the second speed is released while the first brake is maintained while the first clutch and the second clutch are coupled to each other. Obtained by combining the two brakes, and the third speed is obtained by releasing the first and second brakes while maintaining the first, second and third clutches engaged, and the fourth speed is obtained by the second clutch and the first brake. Obtained by combining the first, third clutch and second brake in the released state, the reverse (R-speed) is the second, third clutch and the first brake in the state in which the first clutch and the second brake is released Four-speed automatic transmission, characterized in that to obtain a gear shift by combining.