KR100203482B1 - Belt type cvt - Google Patents

Abstract

The present invention relates to a belt pulley type endless continuously variable transmission, comprising two planetary gear units and one transmission belt pulley, wherein a ring gear of a first planetary gear is connected to an input shaft for transmitting engine power, and a pinion carrier Is fixed, the sun gear is connected to the driving pulley, the driven pulley is connected to the sun gear of the second planetary gear unit, and the pinion carrier is connected to the input shaft through two direct gears, and the ring gear is intermediate The intermediate shaft has a structure connected to the output shaft provided with a differential gear. The endless transmission of the present invention having such a structure can simply control the transmission direction of the power transmitted from the engine to the axle by varying the speed ratio between the drive pulley and the driven pulley, thereby controlling the forward and reverse speed and the speed ratio. There is no need to use a separate control element. In addition, it is possible to reduce the size of the axial direction by using three pulleys as a whole, even if the belt pulley is used as a transmission element. Therefore, it is a simple structure as a whole, and continuously variable speed is made.

Description

Belt Pulley Infinite Speedless Transmission

The present invention relates to a belt type continuously variable transmission, and in particular, the structure is simplified by simply changing the transmission ratio between the pulleys without requiring a separate operating element for controlling the forward and backward movements. In addition, the present invention relates to a belt type infinitely variable transmission that enables the variable speed ratio to be infinitely variable.

In general, a mechanism for transmitting power from a power generating device such as an engine to a driving means such as a vehicle can be controlled as necessary, and the power output from the engine depends on the amount of load applied to the driving means. The transmission is equipped with a transmission that can be changed appropriately, such a transmission has been improved by the improvement of its function and the convenience of operation day by day, various transmissions have been developed, the operation as the transmission used in the most common vehicle among the drive means. Due to the convenience of the automatic transmission is increasingly used.

However, since this automatic transmission has a problem in that its structure is complicated and its performance is poor in the efficiency of power transmission, a solution for this problem has been proposed.

As a result of the research, the proposed continuously variable transmission made it possible to continuously change the power of the engine while maintaining the constant output of the engine regardless of the load applied to the vehicle.

The advent of the continuously variable transmission has made great strides in the performance of a transmission that shifts power, but there have been various problems in achieving the full performance as the original transmission demands.

For example, there is a gear type and a belt type according to the configuration, and the gear type is not necessarily a stepless gear combination, but necessarily a planetary gear unit, and also controls the operation of these planetary gear units. In order to obtain the output and direction of rotation, various operation controls such as brakes and clutches are required, so that they are bulky and heavy, and thus have a disadvantage of being expensive.

On the other hand, there is a belt pulley type using a belt and a pulley as a structure compared to a gear type. In this belt pulley type transmission, since the rotation direction is not changed in the process of transmitting power from the driving pulley to the driven pulley, it is transmitted in the same direction. In order to achieve output in the same direction as the driving direction of the engine in the output shaft, a shaft for installing one external gear for the purpose of switching the rotation direction should be provided.

Therefore, since most belt pulley continuously variable transmissions have a four-axis structure, they have various problems in mounting on a vehicle due to their large volume in the radial direction compared to conventional three-axis manual or automatic transmissions.

In addition, the existing belt pulley continuously variable transmission has a limitation of power transmission in the process of transmitting the power of the engine through the belt, so the size of power transmission is limited. Therefore, the belt type continuously variable transmission that has been put to practical use until now is to be applied only to the 1800cc or less.

In addition, although the transmission range is larger than that of the existing transmission, the diameter of the pulley has to be enlarged in order to obtain a transmission ratio of a wide area required by a vehicle, and thus there is a problem due to the limitation of volume.

Accordingly, the present invention solves the problems described above, and does not require a separate brake and clutch for realizing forward and backward movement, and only forward and neutral movements are achieved by the relative shift between the driven pulley and the driven pulley driven by the belt. And the reverse is to be made, and the three-axis structure to make the belt pulley type infinitely variable transmission that the structure is simple and the volume is reduced.

It is also an object of the present invention to provide a belt pulley type infinitely variable transmission having a higher power transmission efficiency than the conventional one.

The present invention for achieving the object of the above, the first planetary gear unit is installed so as to be freely rotated to the input shaft driven by the driving force of the engine, and is driven by receiving the shifted power from the first planetary gear unit A variable drive pulley whose operating diameter is variable, a variable driven pulley which is connected and driven through the variable driving pulley and a belt, and a second planetary gear that is operated by receiving power from the variable driven pulley Unit, an intermediate shaft for outputting power shifted by the second planetary gear unit, a direct gear installed on the input shaft and directly connected to the pinion carrier of the second planetary gear unit, and a gear connection to the gear installed on the intermediate shaft It is composed of an external gear that outputs finally shifted power.

Then, the engine power is input to the ring gear of the first planetary gear, the sunfun of the first planetary gear unit and the drive pulley are connected to each other, the driven pulley is connected to the sun gear of the second planetary gear unit, The ring gear of the second planetary gear is connected to the intermediate shaft, and the pinion gear is connected to the direct gear installed on the input shaft through the pinion carrier.

Therefore, in the transmission of the present invention having such a structure, the driving force of the engine is transmitted to the second planetary gear unit through the first planetary gear unit and the variable pulley, while the second planetary gear unit is directly connected to the input shaft. In other words, the power of the engine transmitted to the second planetary gear unit is transmitted to the second planetary gear unit through the first planetary gear unit and the variable belt pulley, and on the other hand, a direct gear installed on the input shaft. And pinion gears.

Therefore, the power transmission is smoothly made because the path of the power of the engine is transmitted to the second planetary gear unit in a double.

In addition, since the driving direction of the power transmitted to the intermediate shaft through the ring gear of the second planetary gear unit is rotated in the forward direction, the stationary state or the reverse direction according to the speed ratio between the drive pulley and the driven pulley, the first planetary There is no need for a separate control element to control the operation of the gears and the second planetary gear.

In addition, since it consists of three football groups consisting of an input shaft, which is provided with a first planetary gear and a driving pulley, an intermediate shaft where a second planetary gear and a driven pulley are installed, and a drive shaft that receives and transmits the power shifted from the intermediate shaft. In this case, the radial volume thereof becomes small, which makes it easy to install in a confined space of a vehicle.

1 is a schematic cross-sectional view schematically showing the internal structure of a continuously variable transmission according to the present invention;

2 is a flowchart illustrating a power transmission process of a continuously variable transmission according to the present invention.

Explanation of Reference Symbols in the Drawings

1-engine 2-input shaft

3-1st Planetary Gear Unit 4-Variable Drive Pulley

5-Variable driven pulley 6-Belt pulley set

7-intermediate shaft 8-2nd planetary gear unit

9-Output Gear 10-Drive Gear

11-output shaft 12-ring gear

13-Sun Gear 14-Pinion Gear

15-Belt 16-Moving Mechanism

17-Mobility mechanism 18-Sun gear

19-Ring Gear 20-Pinion Gear

21-Pinion Carrier 22-External Gear

23-Direct Gear

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

1 is a schematic view showing the structure of an endless continuously variable transmission according to the present invention in a cross-sectional form, wherein the continuously variable transmission according to the present invention is installed on an input shaft 2 driven by receiving power from the engine 1 to drive the engine. It consists of a first planetary gear unit (3) for primary shifting, a variable drive pulley (4) and a variable driven pulley (5) for directly receiving and driving the power shifted from the first planetary gear unit (3) A belt pulley set 6 and a second shaft which are installed on the intermediate shaft 7 together with the variable driven pulley 5 so as to make a vehicle shift. It consists of a planetary gear unit (8).

The power shifted from the second planetary gear unit 8 is transferred to the output shaft 11 through an output gear 9 installed on the intermediate shaft 7 and a drive gear 10 engaged with the output gear 9. It is to be delivered.

On the other hand, the first planetary gear unit 2 has a ring gear 12 directly connected to the input shaft 1, a sun gear 13 is connected to the drive pulley 3, the pinion gear 14 is It is a structure fixed to the transmission case 15.

Therefore, the power of the engine 1 is applied to the ring gear 12 of the first planetary gear unit 3, and the shift is performed in the first planetary gear unit 3, and then transmitted to the variable drive pulley 4. You lose.

The variable drive pulley 4 and the variable driven pulley 5 are connected to each other via a power transmission belt 15 to transfer power from the drive pulley 4 to the driven pulley 5. In this case, the pulleys (4.5) have a variable operating diameter so that the transmission ratio of the power transmitted to the driven pulley (5) varies according to the variable aspect of the operating diameter. That is, as the operating mechanism (16.17) provided in each pulley (4, 5) is operated, the diameter (operation diameter) to which the belt 15 is caught is changed, accordingly the drive pulley (4) The larger the operating diameter of and the smaller the driven pulley (5), the larger the ratio of transmission between both belt pulleys (4, 5). The larger the operating diameter of, the smaller the speed ratio between both belt pulleys 4 and 5.

In addition, the sun gear 18 of the second planetary gear unit 8 is directly connected to the driven pulley 5, the ring gear 19 is connected to the intermediate shaft 7, and the pinion gear 20 is The external gear 22 of the pinion carrier 21 is engaged with the direct gear 23 provided in the input shaft 2.

Accordingly, a path through which power is transmitted to the second planetary gear unit 8 is directly connected to a path through which the power is input to the sun gear 18 through the driven pulley 5, as shown in FIG. 2. Through the gear 23 and the pinion carrier 21 is made of a path input to the pinion gear (20).

In this way, the power input in the two paths is shifted by the combination of the speed difference and the gear ratio with respect to the ring gear 19, and the result is output to the intermediate shaft 7 through the ring gear 19. do.

Then, the power transmitted to the output shaft 7 is transferred between the output gear 9 and the drive gear 10 installed on the output shaft 11 to the output shaft 11 while finally shifting according to the gear ratio.

The continuously variable transmission of the present invention having the structure as described above ultimately changes the magnitude of the power input to the second planetary gear unit 18, so that the power discharged to the output shaft 11 through the output gear 9 is alternated. You lose.

Therefore, since the power input to the pinion gear 20 of the second planetary gear unit 2 is always constant, the power input to the sun gear 18 through the variable pulleys 4 and 5 is eventually varied. You lose.

The following describes in detail the shifting process between the neutral and the forward and backward movements.

Neutral

The neutral state refers to a state in which power is not transmitted to the output shaft 11 while the engine is running. At this time, the power transmitted from the engine is dissipated by its own rotational force in the planetary gear units 3 and 8. It's a loss.

Before looking at the power transmission process in detail look at the power transmission characteristics made in each planetary gear unit of the transmission according to the present invention.

First, since the planetary gear unit is composed of a single pinion gear in the first planetary gear unit 3, a general speed ratio formula of the planetary gear unit having a single pinion gear is expressed by Equation 1 below.

Where λ ₁ = number of teeth of sun gear 13 (Z _S ) / number of teeth of ring gear 12 (Z _R ), ω _c1 = angular velocity of pinion gear, ω _r1 = angular velocity of ring gear, ω _S1 = sun gear Is the angular velocity of.

Since the pinion gear 14 of the first planetary gear unit 3 is fixed to the transmission case 15 via the pinion carrier in Equation 1, the angular velocity is zero. That is, ω _c1 = 0 in Equation 1 above.

Therefore, the following equation (2) is obtained.

This is because ω _r1 = ωe.

On the other hand, since the second planetary gear unit 8 is to receive power from the variable driven pulley 5, the rotational speed (ω _S2 ) input to the sun gear 18 of the second planetary gear unit 8 is Equation 2 and Equation 2 can be obtained from the structural relationship in which the sun gear 18 is connected to the driven pulley 5 to receive power.

Here, v _a = reduction ratio by the belt pulley set 6, G = reduction ratio between the direct gear 23 and the external gear 22.

Further, since the second planetary gear unit 8 also has only one pinion gear 20, the following equation (5) is established.

Where λ ₂ = tooth number Z _S of the sun gear 18 / tooth number Z _R of the ring gear 19, ω _c2 = angular velocity of the pinion gear 20, ω _r2 = angular velocity of the ring gear, ω _S2 = angular velocity of the sun gear.

Summarizing Equation 5 with respect to ω _r2 , Becomes

Substituting the above formulas (3) and (4) here, If ωe is enclosed in parentheses in this equation, Equation 6 can be derived.

In Equation 6, since the values of ω e and G and λ are constant values that do not vary, the magnitude of the rotational speed ω _r2 output through the second planetary gear unit 8 is the magnitude of v _a , which is a speed ratio between both belt pulleys. It is decided by.

That is, when the vehicle maintains the neutral state, the speed output from the second planetary gear unit 8 is zero.

Therefore, in order to be ω _r2 = 0, λ ₂ / λ _{1 ·} v _a- (1 + λ ₂ ) G = 0 in Equation 6, so in the case of making the neutral state, the driving pulley 4 and It is a case where the value v _a of the speed ratio between the driven pulleys 5 is equal to (1 + λ ₂ ) · G · λ ₁ / λ ₂ . That is, when v _a = (1 + λ ₂ ) · G λ ₁ / λ ₂ , the neutral state is achieved.

Forward state

The forward state generally refers to a case where the driving direction of the engine and the rotation direction of the output shaft 11 correspond to each other. In order for the output shaft 11 to rotate in the forward direction, the planetary gear units 3 and 8 correspond to the shifting process corresponding thereto. This should be done.

Accordingly, in order to be ω _r2 0, λ ₂ / λ ₁ · v _a − (1 + λ ₂ ) G 0 must also be expressed in Equation 6 above. Therefore, in the case of v _a (1 + lambda ₂ ), G lambda ₁ / lambda ₂ , the output shaft 11 is rotated forward, and such as a vehicle driven by the power transmitted from the output shaft 11 The driving means is to be advanced.

Here, referring to the power transmission direction of each planetary gear unit and the belt pulley set, first, the direction in which the engine is driven is defined as forward rotation, and the pinion gear in the first planetary gear unit 3 that receives rotation from the engine is rotated. Since 14 is fixed so as not to revolve, the rotation direction of the sun gear 13 is reversed.

Accordingly, the driving pulley 4 connected to the sun gear 13 and driven is reversely rotated, and the driven pulley 5 connected to the driving pulley 4 and the belt 15 to receive power also has the same direction. That is, the driving in the reverse rotation direction.

In addition, the sun gear 18 of the second planetary gear unit 8 driven by receiving power from the driven pulley 5 is also reversely rotated, while the input shaft 2 and the direct gear 23 and the external gear ( The pinion gear 20 which receives the power of the engine directly through 22 is rotated forward. Therefore, the ring gear 19 which rotates in engagement with the pinion gear 20 is reversely rotated, and the intermediate shaft 7 which is rotated by receiving power from the ring gear 19 is also reversed.

In addition, the output gear 9 provided on the intermediate shaft 7 also rotates in reverse, and the output shaft 11 that receives power through the external gear 10 meshed with the output gear 9 in a circumferential state is It is to be rotated forward.

In the power transmission process as described above, the power transmission direction input from the engine to the sun gear 18 of the second planetary gear unit 8 and the power transmission direction transmitted to the pinion gear 20 are always the same, but the sun gear According to the relative speed generated between the rotational speed of 18 and the rotational speed of the pinion gear 20, the ring gear 19 is rotated forward or reverse.

Therefore, when the rotation direction of the power transmitted from the ring gear 19 of the second planetary gear unit 8 to the intermediate shaft 7 is reversely rotated, the drive gear and the output gear 9 are driven from the intermediate shaft 7. The output shaft 11 that receives power through the gear 10 is to be rotated forward.

Therefore, in order to rotate the output shaft 11 in the forward direction,

The condition of ω _r2 0 must be satisfied.

Accordingly, in order to be ω _r2 0, λ ₂ / λ ₁ · v _a − (1 + λ ₂ ) G 0 must also be expressed in Equation 6 above. Therefore, in the case of v _a (1 + lambda ₂ ), G lambda ₁ / lambda ₂ , the output shaft 11 is rotated forward, and such as a vehicle driven by the power transmitted from the output shaft 11 The driving means is to be advanced.

In addition, since the speed of the output shaft 11 is increased as the rotational speed (RPM) of the engine is increased, the rotational speed of the output shaft 11 is increased without interruption, thereby making the stepless shift.

Backward

In the above bar, since the intermediate shaft 7 has to be rotated forward in order for the output shaft 11 to reverse, the condition of ω _r2 0 in Equation 6 must be satisfied. Accordingly, in the case of λ ₂ / λ ₁ · v _a − (1 + λ ₂ ) G 0 in the above equation (6), the intermediate axis 7 is rotated forward, and the intermediate axis 7 and the output gear 9 are And the output shaft 11 which is connected through the drive gear 10 is to be reversed.

In addition, even in the reverse state, as the rotational speed of the engine increases, the rotational speed of the output shaft 11 increases, thereby making the stepless shifting.

As described above, the continuously variable transmission according to the present invention maintains a neutral state in which the output shaft 11 is not driven or rotates forward or reversely according to the gear ratio of the belt pulley set 6, so that the reverse rotation can be reversed. There is no need for a separate operating mechanism, ie clutches, breakers or one-way clutches used in conventional automatic transmissions or continuously variable transmissions.

Therefore, the internal structure of the transmission can be made extremely simple. In particular, since only three shafts need to be used without using a separate auxiliary means while using a belt pulley set, the volume of the transmission can be reduced in the radial direction. It is possible to easily mount to a drive mechanism subject to a lot of restrictions on the place, such as to install the transmission, it is possible to reduce the production feeling.

Since the mechanism for transmitting power shifted to the second planetary gear unit 8 is composed of a belt pulley set 6, the output shaft 11 is caused by the combination of the gear ratio of the belt pulley set and the rotational speed of the engine. Since the speed ratio of the variable can be infinitely varied, infinitely continuously variable speed is achieved as a whole. In particular, the power transmission is not merely made of the belt, but the direct gear 23 and the external gear (installed on the belt 15 and the input shaft 2). Also, through 22), the power is transmitted in parallel so that the power transmission efficiency is increased.

Therefore, it can be attached to a vehicle using a large engine but a continuously variable transmission using a belt.

Claims (1)

The first planetary gear unit 3 installed on the input shaft 2 driven by the driving force of the engine 1 and the power shifted by the first planetary gear unit 3 are received from the variable drive pulley 4 to be variable. Belt pulley type including a belt ruler set 6 which is secondarily shifted through the driven pulley 5 and a second planetary gear unit 8 which receives power from the belt pulley set 6 and shifts it to the output shaft. In the continuously variable transmission, the input shaft (2) is directly connected to the ring gear (12) of the first planetary contribution unit (3), and the sun gear (13) of the first user unit (3) is the variable drive pulley ( 4), the pinion gear 14 is fixed to the transmission case 15 via a carrier, while the variable driven pulley 5 is connected to the sun gear 18 of the second planetary gear unit (8). Now, the pinion gears 20 of the two planetary gear units 8 are connected to the direct gear 23 installed on the input shaft 2 via the carrier 21. Is, and the second planetary gear set ring gear of unit (8) (19) is a belt pulley expression infinite variable transmission structure connected to the output shaft 11 to the intermediate output gear 9 is installed on the intermediate shaft (7)