KR20080107088A - Continuously variable transmission having high efficiency - Google Patents

Abstract

A continuously variable transmission having high efficiency is provided to reduce the fabrication cost and simplify the structure by jointing the necessary element for the mode preferences to the planetary gear system. A continuously variable transmission comprises the belt speed change part(30), the connection gear system(40), the planetary gear system(50), and the mode selection part(60). The belt speed change part changes the gear ratio of the first power which corresponds to the driving resistance of the output axis(71) when the first power generated in a boiler is inputted through the first input shaft(31) and is inputted without notice. The planetary gear system changes the first power inputted to the sun gear through the first input shaft. The planetary gear system mixes the second power which is inputted to the ring gear(54) with the carrier(55) and delivers to the output shaft.

Description

Continuously Variable Transmission Having High Efficiency

1 is a schematic configuration diagram showing a conventional belt-type continuously variable transmission,

2 is a schematic configuration diagram showing an overall configuration of a high efficiency continuously variable transmission according to a first embodiment of the present invention;

3 is an explanatory diagram showing a power transmission process of the high efficiency continuously variable transmission according to the first embodiment shown in FIG.

4 is an explanatory diagram for explaining a speed ratio of a high efficiency continuously variable transmission according to the first embodiment shown in FIG. 2;

5 is a schematic block diagram showing the overall configuration of a high efficiency continuously variable transmission according to a second embodiment of the present invention.

* Explanation of Signs of Major Parts of Drawings *

20: torque converter 21: input shaft

22 impeller 22a pump housing

23: turbine 24: stator

25: one-way clutch 26: fixed shaft

27: lock-up clutch 30: belt transmission

31: first input shaft 32: drive pulley

33: driven pulley 34: belt

40: connecting gear system 41: second input shaft

42: first connecting gear 43: connecting pinion gear

44: fixed shaft 45: second connecting gear

50: planetary gear system 51: sun gear

52: first planetary pinion gear 53: second planetary pinion gear

54 ring gear 55 carrier

60: mode selector 61: forward clutch

62: reverse brake 63: lock-up clutch

71: output shaft

The present invention relates to a high efficiency continuously variable transmission, and more particularly, to a high efficiency continuously variable transmission having a wide speed ratio, a high fuel economy, and excellent durability.

In general, since the driving force of the vehicle varies greatly depending on the weight of the vehicle, the road situation, and the driving speed, the vehicle has been used by installing a transmission that appropriately changes the driving force of the engine according to the situation.

Such a vehicle transmission device is installed between the engine and the drive shaft and has a function of transmitting the driving force of the engine to the drive wheels. The manual transmission device directly selects a shift stage at the driver's will, and automatically according to the driving conditions of the vehicle. It is divided into an automatic transmission in which a shift is made, and a continuously variable transmission in which continuously shifting is carried out without a specific shift range between each shift stage.

Among these transmissions, a manual transmission is provided with a shift lever for receiving a driver's operation force, and the shift lever operates a plurality of shift rails installed in a shift gear box to operate a plurality of gears through a sleeve connected to a shift fork. In order to achieve this, the clutch must be stepped on to cut off the power transmitted from the engine.

The manual transmission as described above has the advantages of simple structure, excellent durability, and high transmission efficiency, but has a problem in that a driver must directly operate a shift stage continuously changing according to a vehicle speed during driving, and noise / vibration is large. Therefore, the driver who is not used to driving had the biggest problem of causing various accidents due to immature shifting operation, and even an experienced driver quickly felt fatigue when driving for a long time.

On the other hand, the automatic transmission can achieve a constant gear ratio between the input and output elements of the power by fixing one of the sun gear, the carrier and the ring gear forming the planetary gear by the multi-plate clutch and band brake that control the planet gear. In addition, if two elements are fixed to each other, they are integrally rotated, and if none of them is fixed, it is set to a neutral state where power is not transmitted.

Therefore, the automatic transmission can be automatically shifted without the gear shifting with only the accelerator pedal and the brake pedal, since the manual clutch operation mechanism is omitted, but the hydraulic and electronic control structure for fixed control of the planetary gear device with the multi-plate clutch and the band brake It is very complicated and the durability is low, in particular, the manufacturing cost is high, there was a problem of low transmission efficiency. In addition, the automatic transmission has a shift shock when the speed is shifted up or down according to the shift ratio of each shift stage.

Moreover, the conventional manual and automatic transmissions are fixed and operate at a constant gear ratio, which makes it difficult to use the optimum output and fuel economy, thereby making the transmission multi-stage, but the weight and cost of the device are limited.

In addition, the continuously variable transmission has been developed for the purpose of eliminating the shift shock which is a disadvantage of the automatic transmission and at the same time reducing the cost and improving fuel economy.

Conventional continuously variable transmissions have great advantages in terms of fuel economy, power transmission performance, and weight by securing disadvantages of automatic transmissions using hydraulic pressure, and such continuously variable transmissions utilize belt displacements of diameters of pulleys mounted on input shafts and output shafts. Equipped with the stepless speed shifting method, the fuel economy is poor at low and high speeds, and the amount of exhaust gas generated is high, and durability, noise / vibration, and slippage are caused by the use of a power transmission belt.

In addition, the conventional belt type continuously variable transmission includes a torque converter 1, a planetary gear system 2, a belt transmission portion 3, a connecting gear 4, and a differential device 5 as shown in FIG. ) Is included.

In this case, the planetary gear system 2 connects the reverse brake 6 to the ring gear 11, and the forward gear 7 connects the carrier 13 connected to the input shaft 10 and the sun gear 12 connected to the output shaft 17. It has a structure combined by). Therefore, the planetary gear system 2 is not shifted and merely serves to change the forward and backward modes.

Therefore, the conventional continuously variable transmission shown in FIG. 1 covers the entire transmission area only by the speed ratio of the belt transmission portion 3 to which the driving pulley 14 and the driven pulley 15 are connected by the belt 16. The range of the transmission ratio is also limited by the limit of the size of the speed change section 3.

That is, the conventional belt shifting part 3 has a disadvantage in that the range of the speed ratio is limited for the same reason as described above, and requires a large moving distance of the pulleys 14 and 15 for shifting. In addition, due to the limitation of the shift range, a large reduction ratio has to be formed in the differential apparatus 5, which leads to deterioration in efficiency.

On the other hand, Korean Patent Laid-Open Publication No. 1999-24503 discloses a first pulley shaft, a first pulley on a first pulley shaft, and a second pulley shaft rotatably installed on an input shaft, an output shaft, and an output shaft. A shift adjusting portion having a second pulley and a shift adjusting belt installed, a first connector integrally formed with the second pulley shaft, a connection portion having a second connector and a third connector integrally formed with the output shaft, and installed between the input shaft and the shift adjusting portion It is proposed a continuously variable transmission having a wide speed ratio, comprising a gear set in a gear set, and operatively connecting each component of the gear to an input shaft, an output shaft, and a first pulley shaft.

In addition, since the continuously variable transmission has high speed and high efficiency at low and high stages, the continuously variable transmission can be applied to a large passenger car and a driving body using high torque without deterioration in transmission efficiency under high torque.

However, the continuously variable transmission does not include a clutch mechanism for separating the shift adjusting unit when the CVT enters the lock-up state for high-speed driving, so that power is transmitted to the shift adjusting unit even in the lock-up state, causing the belt to spin. This occurs, which causes a decrease in efficiency.

In addition, the continuously variable transmission device has to separately include a forward / reverse part for selecting a driving mode on the input shaft, which results in a complicated structure and an increase in size, thereby increasing manufacturing costs.

On the other hand, Patent Application Publication No. 2006-9190 also proposes a continuously variable transmission having an extended speed range, but the overall structure is complicated and a separate direction switching device is adopted to select an operation mode. It is becoming a factor of the increase in manufacturing costs.

Accordingly, the present invention has been made in view of the problems of the prior art, and an object thereof is to provide a high efficiency continuously variable transmission having a wide speed ratio, high fuel economy, and excellent durability.

Another object of the present invention is to provide a continuously variable transmission in which the structure is simple and inexpensive because the elements necessary for mode selection are coupled to the planetary gear system without employing a separate configuration for the power transmission shaft for the operation mode selection. have.

Still another object of the present invention is to provide a continuously variable transmission that can obtain a good effect in improving environmental problems because of the high efficiency of exhaust gas reduction due to high efficiency.

In order to achieve the above object, the present invention provides a belt transmission unit for continuously changing the speed ratio of the first power input corresponding to the running resistance of the output shaft when the first power generated in the engine is input through the first input shaft; And a connection gear system for transmitting a second power obtained by increasing torque of the first speed continuously variable through the belt shifting unit to a rear stage, and a first power input through a first input shaft to the first gear and shifting the first power. It is composed of a planetary gear system for mixing the second power inputted by the ring gear through the second input shaft from the system to the carrier to transfer to the output shaft, and a mode selection unit for selecting the operation mode of the transmission in combination with the set element of the planetary gear system It provides a continuously variable transmission characterized in that.

The planetary gear system includes a sun gear integrally connected to the first input shaft, a first planetary pinion gear meshed with the sun gear to receive rotation, a second planetary pinion gear meshed with the first planetary pinion gear, A ring gear meshed with the second planetary pinion gear and a carrier supporting the first and second planetary pinion gears and integrally connected to the output shaft;

The mode selector includes a forward clutch for selectively coupling the second connection gear and the ring gear to set the forward driving mode, a reverse brake for selectively stopping the ring gear to set the reverse driving mode, and a high speed. It is composed of a lock-up clutch for selectively integrally coupling the ring gear and the carrier to improve the efficiency in the.

The forward driving mode is set by engaging the forward clutch and separating the reverse brake and the lock-up clutch, and the overdrive mode releases the lock-up clutch while the reverse brake is released and the lock-up clutch is engaged. And the forward traveling mode is set by engaging the forward clutch and the reverse brake with the lock-up clutch disengaged.

In addition, the belt transmission unit is connected to the shaft coupled to the first input shaft integrally driven according to the driving state of the vehicle, driven pulley receiving the power of the drive pulley, and connecting the drive pulley and the driven pulley It is composed of a belt, the width of the grooves of the drive pulley and the driven pulley is narrowed, the transmission ratio is determined according to the change in the effective radius that the belt is over,

The connecting gear system includes a first connecting gear integrally connected to a shaft of a driven pulley, a connecting pinion gear supported on a fixed shaft and engaged with the first connecting gear, and a ring gear of the planetary gear system engaged with the connecting pinion gear. It is composed of a second connecting gear for transmitting power to the furnace, and generates the output reduced by a predetermined reduction ratio as a second power to transmit to the ring gear through the second input shaft.

In this case, the first input shaft is rotatably installed inside the second input shaft to connect the driving pulley and the sun gear.

The present invention may further include a torque converter which receives the first power generated in the engine through the input shaft and transmits the torque converted power to the first input shaft.

The torque converter preferably further comprises a lock-up clutch for integrating the pump housing and the first input shaft at high speed rotation between the input shaft and the first input shaft.

(Example)

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

2 is a schematic configuration diagram showing an overall configuration of a continuously variable transmission according to the first embodiment of the present invention, and FIG. 3 is an explanatory view showing a power transmission process for the continuously variable transmission of the first embodiment shown in FIG.

As shown in FIG. 2, the continuously variable transmission according to the first embodiment of the present invention receives a first power generated by an engine through an input shaft 21 and transmits power to the first input shaft 31. torque converter 20, the belt transmission unit 30 for automatically adjusting the speed ratio of the first power input corresponding to the running resistance of the output shaft 71, stepless through the belt transmission unit 30 The gear system 40 which transmits the second power obtained by increasing the speed of the first power shifted to the rear end, and the first gear inputted through the first input shaft 31 are shifted, and then the gear system 40 is shifted. And a planetary gear system 50 for mixing the second power inputted to the ring gear 54 through the second input shaft 41 to the carrier 55 to be transmitted to the output shaft 71, and the planetary gear system 50. And a mode selector 60 for selecting an operation mode of the transmission in combination with a set element of have.

The torque converter 20 is the same as that used in a general automatic transmission and a continuously variable transmission, and an impeller 22 into which engine power is input from an input shaft 21 through a pump housing 22a, and the impeller 22 and Turbine (23) facing each other, the stator 24 installed on the hollow fixed shaft (26) for increasing torque between the impeller (22) and the turbine (23), and once the power is transmitted to improve fuel efficiency It is composed of a lock-up clutch 27 that makes the rotation of the impeller 22 and the turbine 23 integrally. That is, a lock-up clutch for integrating the pump housing 22a and the first input shaft 31 at high speed rotation between the pump housing 22a, that is, the input shaft 21 and the first input shaft 31, to increase efficiency. (27) is provided.

One-way clutch 25 is installed between the stator 25 and the fixed shaft 26 to prevent the reverse rotation of the stator 25 and to rotate in one direction.

The turbine 23 and the lock-up clutch 27 are integrally formed by spline coupling to the first input shaft 31, and the other end of the first input shaft 31 is the driving pulley 32 of the belt shifting portion 30. ), The hollow fixed shaft 26 is coaxially inserted into the first input shaft 31 and fixed to the housing.

In addition, the belt transmission part 30 has a drive pulley 32 which is connected to the first input shaft 31 integrally and varies according to a driving state of the vehicle, and a driven body receiving power from the drive pulley 32. The pulley 33 and the belt 34 which connects the said driving pulley 32 and the driven pulley 33 are comprised. The belt transmission unit 30 is an apparatus for automatically adjusting the transmission ratio in an unauthorized manner in response to the running resistance of the output shaft 71. Since the belt transmission unit 30 uses a well-known structure, detailed configuration and operation thereof will be omitted.

In general, the belt transmission portion 30 of the continuously variable transmission has an input side and an output side, that is, one side of the driving pulley 32 and the driven pulley 33 (Pulley) can move in the axial direction, thereby changing the groove width of the pulley. Continuous transmission ratio can be obtained.

Increasing the hydraulic pressure acting on the hydraulic system for moving the drive pulley 32 narrows the groove width of the pulley, which increases the effective radius of the belt 34, and at this time, the radius of the driven pulley 33 is reversed, so that driving The speed difference between the pulley 32 and the driven pulley 33 becomes large. The effective radius ratio of the drive pulley 32 and the driven pulley 33 becomes the speed ratio, that is, the speed ratio, and the speed ratio can be changed by changing the oil pressure applied to the hydraulic system for moving the drive pulley 32.

The driven pulley 33 determines the pressing force of the belt 34 by acting hydraulic pressure set in accordance with basic characteristics such as transmission torque, and the belt transmission unit 30 is mutually coupled to transmit power at a continuous speed ratio. Drive pulleys 32 and driven pulleys 33 with differently varying radial ratios are used. In this way, the belt transmission part 30 transmits power through friction between the driving and driven pulleys 32 and 33 and the belt 34.

In addition, the connection gear system 40 which decelerates the output of the belt shifting unit 30 and transmits the rear gear to the rear end is first connected to the first connection gear 42 and the fixed shaft 44 integrally with the shaft of the driven pulley 33. Is connected to the first pinion gear 43 and the first pinion gear 43, and the first pinion gear 43 is engaged with the first pinion gear 43 to transfer power to the ring gear 54 of the planetary gear system 50. The second connecting gear 45 is configured.

On the other hand, the planetary gear system 50 is an input line gear 51 which is integrally connected to the first input shaft 31, the first planetary pinion gear 52 which is meshed with the input line gear 51 and receives a rotation, and the A second planetary pinion gear 53 engaged with the first planetary pinion gear 52, a ring gear 54 engaged with the second planetary pinion gear 53, and the first and second planetary pinions It supports the gears 52 and 53, and is comprised from the carrier 55 connected with the output shaft 71 integrally.

The output of the second connecting gear 45 is connected to one end of the second input shaft 41, the other end of the second input shaft is connected to the ring gear 54 of the planetary gear system 50 through the forward clutch 61 The first input shaft 31 is rotatably installed in the second input shaft 41 to connect the driving pulley 32 and the input sun gear 51.

According to the present invention, the power transmission for the three elements of the planetary gear system 50 is selectively interrupted / connected without providing a mode selection means 60 for setting the rotation ratio and the shift stage for each operating state.

That is, the mode selector 60 firstly has a forward clutch 61 installed between the second connecting gear 45 and the ring gear 54 of the planetary gear system 50 and a ring of the planetary gear system 50 for the forward state. A reverse brake 62 installed to achieve a stationary state of the gear 54, and a lock-up clutch 63 for unifying the ring gear 54 and the output carrier 55 to improve efficiency at high speed. Consists of.

As shown in FIG. 2, the high efficiency continuously variable transmission according to the first embodiment of the present invention has a structure similar to that of a CVT of a general belt type. However, in the present invention, the torque converter 20 is applied as a power transmission medium for transmitting the power output from the engine to the belt transmission unit 30 and the planetary gear system 50, and is transmitted through the torque converter 20. The power of the engine is supplied to the belt transmission unit 30 for stepless speed change and the input sun gear 51 of the planetary gear system 50 as described below, and after the shift is made, the output shaft 71 is coupled to the planetary gear system 50. Adopts the dual shift method to obtain the shift output of the continuously variable transmission.

The shift principle of the continuously variable transmission is to automatically adjust one of the set elements of the torque converter 20 and the planetary gear system 50 that receive engine power to a speed ratio corresponding to the load state of the output shaft 71. In the neutral state, the power is continuously transmitted to the overdrive (O / D) rotation ratio and transmitted to the output shaft 71.

In this case, in the continuously variable transmission of the present invention, the planetary gear system 50 has a speed ratio determined according to the gear tooth ratio of the input sun gear 51 and the ring gear 54 irrespective of the first and second planetary pinion gears 52 and 53. According to the first transmission power generated in the engine applied to the input line gear 51 is transmitted to the output shaft 71, the belt transmission portion 30 according to the load applied to the output shaft 71 drive pulley 32 And the transmission ratio between the driven pulley 33 is continuously adjusted to generate a shifted output, and the connection gear system 40 further reduces the continuously shifted output through the belt shifting portion 30 at a predetermined ratio. By increasing the torque by acting to transmit to the planetary gear system (50).

1. How it works

Looking at the operating principle of the high-efficiency continuously variable transmission according to the first embodiment of the present invention, first, the first power from the engine is divided into two branches as shown in Figure 3, one through the first input shaft (31) planetary gear system (50) ), And the other is transmitted to the belt transmission part (30).

Thereafter, the first power applied to the belt shifting portion 30 is automatically adjusted according to the load applied to the output shaft 71 and transmitted to the ring gear 54 of the planetary gear system 50 at the second power shifted to the planetary gear system. The first power input to the sun gear 51 of the 50 is added again, and outputs through the carrier 55 of the planetary gear system 50. At this time, the belt transmission part 30 is automatically shifted according to the load on the output side, and then the torque is increased through the connecting gear system 40, and together with the planetary gear system 50 serves to adjust the mutual speed ratio.

Looking at the flow of power, the first power coming from the engine is divided into the belt transmission portion 30 and the sun gear 51 of the planetary gear system 50. The power shifted through the belt transmission part 30 is increased in torque through the coupling gear system 40 so that the second power is transmitted to the ring gear 54 of the planetary gear system 50, which is transmitted through the input sun gear 51. It is combined with the input first power to determine the output.

In addition, most of the second power coming into the ring gear 54 of the planetary gear system 50 through the belt transmission unit 30 and the connection gear system 40 is transmitted to the output side through the carrier 55, the rest A part is fed back to the first input shaft 31 through the sun gear 51 via the first and second planetary pinion gears 52 and 53 of the planetary gear system 50, and the part of the fed back power is the engine. Mixed with the first power coming from the belt shift portion 30 is entered. That is, power circulation is performed in the power transmission system.

2. Description of operation by operation mode

Hereinafter, the continuously variable transmission according to the first embodiment of the present invention will be described in detail with respect to the power transmission process for each operation mode.

The power transmission process will be described according to the neutral, forward driving (ie driving mode 1), high speed driving (ie driving mode 2) and reverse driving modes. Prior to this, the setting states of the forward clutch 61, the lock-up clutch 63, and the reverse brake 62, which are components for each operation mode, are shown in Table 1 below.

Operating mode Forward Clutch Reverse Brake Lock-up clutch Neutral mode (N) detach detach detach Forward driving mode 1 (D1) (slow to medium speed) Combination detach detach Forward driving mode 2 (D2) (High-speed O / D) Combine after separation detach After combining Reverse travel mode (R) detach detach detach

(1) Neutral mode (N)

In the neutral mode N, both the forward clutch 61, the lock-up clutch 63, and the reverse brake 62 are in a disconnected state, and the output shaft 71 is stopped.

In this neutral mode (N) is a state in which the gears of the planetary gear system 50 is idle when the input first power does not rotate the output shaft (71). That is, the first power transmitted from the engine is connected to the carrier 55 of the planetary gear system 50 because both the brake 62 and the clutches 61 and 63 which are connected to the planetary gear system 50 are released. The load on the output shaft 71 does not generate a rotational force that can generate output in the planetary gear, and the power is dissipated in the planetary gear to achieve a neutral state.

(2) Forward driving mode 1 (D1) (from low speed to medium / high speed)

In the forward driving mode 1 (D1), the reverse brake 62 and the lock-up clutch 63 are deactivated and only the forward clutch 61 is operated.

In the forward traveling mode 1 (D1), the rotation of the output shaft 71 which has been stopped in the neutral mode (N) gradually increases until the rotation ratio of about 0.8 to 0.9 with the first input shaft 31 is reached. Gradually increasing the speed at a low rotational speed of the engine increases the rotational speed of the impeller 22 of the torque converter 20, and thus increases the rotation of the turbine 23 while increasing the force of the discharged fluid.

As the first power with increased torque through the torque converter 20 is applied to the shaft of the drive pulley 32 of the belt transmission part 30 through the first input shaft 31, a part of the first power is driven by the belt. Passed through the 34 to the driven pulley 33, the remaining power of the first power is transmitted to the sun gear 51 of the planetary gear system 50 in series with the axis of the drive pulley 32, respectively.

In this case, the carrier 55 is in a stopped state by the load of the output shaft 71 connected to the carrier 55 of the planetary gear system 50. As the rotation of the engine is gradually increased, the rotation of the turbine 23 connected to the input shaft 21 is also increased, and the driving belt 34 of the belt transmission unit 30 and the sun gear 51 of the planetary gear system 50 are also larger. Will rotate.

However, the sun gear 51 of the planetary gear system 50 does not overcome the load on the carrier 55 connected to the output shaft 71, and eventually the power is fed back to the drive pulley 32 of the belt transmission 30. The power thus fed back causes the driven pulley 33 to rotate through the drive pulley 32. The driven pulley 33 transmitted through the drive pulley 32 is initially powered by a first decelerated rotation to produce a large torque, and the decelerated rotational force is the first connecting gear connected to the belt transmission 30. It is transmitted to 42 and to the second connecting gear 45 via the connecting pinion gear 43.

Since the forward clutch 61 is in operation while the second power transmitted to the second connection gear 45 causes a large torque increase due to the reduced rotational force, the ring gear 54 of the planetary gear system 50 is moved through the forward clutch 61. Will be delivered). The power transmitted to the planetary gear system 50 is combined with the first power of the engine transmitted through the input sun gear 51 to overcome the load on the output shaft 71 and rotate the carrier 55.

Looking back on this process, the rotational force transmitted to the input sun gear 51 of the planetary gear system 50 through the first input shaft 31 is the output shaft 71 connected to the carrier 55 in the planetary gear system 50. In the state in which there is no part for increasing the torque for rotating the carrier 55, the rotation is eliminated through the ring gear 54 without rotating the carrier 55.

However, the rotation of the first input shaft 31 transmitted simultaneously with the planetary gear system 50 is rotated by decelerating the driven pulley 33 through the driving pulley 32 at the first low speed and integrally with the driven pulley 33. The connected first connecting gear 42 is also transmitted to the second connecting gear 45 by the decelerated rotation once again through the connecting pinion gear 43, and thus the decelerated rotational force over the second time has a large torque multiplication effect. A rotational force (POWER) capable of rotating the ring gear 54 connected through the forward clutch 61 is generated.

When the ring gear 54 rotates, the carrier 55 is balanced with a load on the carrier 55 integrally connected to the output shaft 71 together with the rotational force input through the input sun gear 51 of the planetary gear system 50. Rotated). This is the initial starting state.

For example, the ratio of the diameter at which the belt 34 of the driving pulley 32 contacts the belt 34 of the driven pulley 33 at the time of low speed start is at this point: It is set to 2, the tooth ratio of the first coupling gear 42 and the second connection gear 45 is set to 1: 2, the tooth ratio of the sun gear 51 and the ring gear 54 in the planetary gear system 50 is 1 It is assumed that it is set to 5.

Since the radius of the driving pulley 32 in contact with the belt 34 at the initial start is small, the position of the driven pulley 33 is in a large radius, so that the driven pulley 33 is approximately 1 / r than the rotation of the driving pulley 32. When the rotation is decelerated by about two decelerations, and the second and second connection gears 42 and 45 are decelerated again by 1/2, the rotation transmitted to the ring gear 54 is eventually transmitted to the drive pulley 32. It rotates with a rotation that is about 1/4 slower than the rotation. Looking at the rotation of the planetary gear system 50, when the carrier 55 is in a stationary state, the ring gear 54 slightly varies depending on the gear tooth ratio in the same direction as the input sun gear 51, but the sun gear 51 and the ring gear 54 By setting the tooth ratio of, it is possible to obtain a rotation ratio that is sufficiently decelerated. The graph shown in FIG. 4 shows an example in which the tooth ratio of the sun gear 51 and the ring gear 54 is set to 1: 5.

The rotation of the first power input as described above obtains a large rotational force through deceleration, and thus the initial driving force is obtained, and when the starting point is started, the load on the output shaft 71 is reduced so that the driving pulley 32 and the driven pulley 33 are reduced. As the rotation rate of the rotation is gradually increased at a high speed, the deceleration is reduced and the number of rotations is increased, so that the speed of the output shaft 71 is also gradually increased.

As the carrier 55 rotates as described above, the load on the output shaft 71 decreases and the rotation speed of the planetary gear system 50 also increases due to the reduced load. Then, while adjusting the gear ratio of the driving pulley 32 and the driven pulley 33, it is possible to gradually increase the rotation speed, and eventually increase the rotation of the output shaft 71 to a speed ratio of about 1: 0.8 to 0.9 of the input rotation. . This state is referred to as forward mode 1 (D1).

(3) Forward driving mode 2 (D2) (high speed driving)

The forward driving mode 2 (D2) is a state in which the lock-up clutch 63 is released after a predetermined speed after selectively operating one of the forward clutch 51 and the lock-up clutch 63.

That is, when the rotational force input due to the forward traveling mode 1 (D1) to which the forward clutch 61 is connected reaches a state above the medium speed, that is, the rotation of the output shaft 71 reaches a speed ratio of 1: 0.8 to 0.9 of the input rotation. In the case of increase, first the forward clutch 61 is deactivated and the lock-up clutch 63 is activated. Then, the power input through the sun gear 51 of the planetary gear system 50 becomes a lock with the ring gear 51 of the planetary gear system 50 through the lock-up clutch 63. As such, when the two elements of the planetary gear system 50 are locked (fixed), the planetary gear system 50 is integrally connected and rotates at a rotation ratio of 1: 1 equal to the input rotation ratio (see FIG. 4).

If the speed is gradually increased while rotating in the same rotation as the input rotation, it is necessary to rotate the output shaft 71 faster than the rotation of the engine, which is called an overdrive (O / D). In the O / D state, the lock-up clutch 63 is released again, and only the forward clutch 61 is operated again. When the first power input from the engine is transmitted from the drive pulley 32 to the driven pulley 33 through the belt shifting portion 30, the driven pulley 33 is rotated by a rotation more than twice as large as that of the drive pulley 32. In this case, the increased rotation through the coupling gear system 30 causes the ring gear 54 of the planetary gear system 50 to rotate at a higher speed than the rotation of the input sun gear 51 due to the connection of the forward clutch 61.

That is, when the ring gear 54 is rotated by the increased rotation than the rotation transmitted to the input sun gear 51 through the first input shaft 31, the carrier 55 of the planetary gear system 50 also rotates the input sun gear 51. The rotation is increased than the rotation of. This is called O / D (see FIG. 4).

(4) Reverse travel mode (R)

The reverse driving mode R deactivates the forward clutch 61 and the lock-up clutch 63 and operates the reverse brake 62 connected to the ring gear 54 of the planetary gear system 50 to operate the ring gear. (54) is fixed.

The rotation input from the engine is transmitted to the input sun gear 51 of the planetary gear system 50, and at this time, by the first and second planetary pinion gears 52 and 53 assembled to the carrier 55 of the planetary gear system 50. Since the ring gear 54 is transmitted to the ring gear 54 and is stopped by the operation of the reverse brake 62, it cannot be rotated, so that the rotation of the input sun gear 51 causes the first and second planetary pinion gears to rotate. The carrier 55 rotates in the opposite direction of the input through the 52 and 53. This is called a reverse driving mode (see FIG. 4).

FIG. 4 is a speed ratio graph illustrating speed ratio values obtained by the input and output carriers 55 of the ring gear 54 when the reference value of the first power input to the sun gear 51 of the planetary gear system 50 is set to 100. FIG.

Referring to FIG. 4, the continuously variable transmission according to the first exemplary embodiment of the present invention has a sun gear 51 and a ring in the ring gear 54 when the carrier 55 is in a stopped state (that is, the carrier output is zero). Since the number of teeth of the gear 54 is set to 1: 5, a value of 100 (reference value) x 1/5 = 20 is applied from the second power that has passed through the belt transmission portion 30 and the coupling gear system 40.

Further, the low speed starting state is determined by the ring gear 54 according to the rotation ratio (1: 2) of the drive pulley 32 and the driven pulley 33 and the gear ratio (1: 2) of the first and second connecting gears 42 and 45. ), A value of 100 (reference value) x 1/4 = 25 is set. In this case, the high speed deceleration value of 6.25 is applied to the output carrier 55, and low speed start is made.

Then, when the rotation ratio of the input-to-output reaches 0.8 to 0.9, the shift ratio difference, that is, the difference between the input and the output is not large, that is, the shift shock is not large and the lock-up clutch 63 is operated to enter the lock-up state.

In addition, the ring gear 51 and the carrier 55 are locked up, and the rotation ratio is set to 1: 1, thereby entering the overdrive (O / D) mode.

Therefore, in the present invention, the output obtained from the output carrier 55, as shown in Figure 4 has a speed ratio in the range of 0.0625 to 1.1563, the speed ratio width is greatly increased compared to the speed ratio width of the conventional belt-type continuously variable transmission shown in FIG. It is.

In the continuously variable transmission according to the first embodiment of the present invention, in order to select one of the forward driving modes D1 and D2, the backward driving mode R, and the neutral mode N, a separate forward / reverse part or direction as in the related art is used. Since the forward clutch 61, the reverse brake 62, and the lock-up clutch 63 of the mode selector 60 are coupled to selectively control the ring gear of the planetary gear system 50 without employing a switching device. The size of the device can be minimized, thus reducing the manufacturing cost.

The above description of each operation mode has been described based on driving conditions of the vehicle for convenience of description, but the present invention is not limited to the automobile only, and when applied to other industrial or power transmission devices, the torque converter is not required first, and the connected gear system and It is possible to apply to other power transmission devices by adjusting the belt ratio of the belt transmission.

5 is a schematic block diagram showing the overall configuration of a high efficiency continuously variable transmission according to a second embodiment of the present invention.

The continuously variable transmission of the second embodiment shown in FIG. 5 has the same structure as the first embodiment except that a magnetic clutch 80 is used instead of the torque converter 20 in the first embodiment. When the electromagnetic clutch 80 is used, the shifting or torque multiplication is lower than that of the torque converter 20, but the structure is simple, small in size, and low in cost.

In the continuously variable transmission of the second embodiment, the mode of the belt transmission unit 30, the coupling gear system 40, and the planetary gear system 50 and the mode selection unit 60 for selecting the operation mode are the same as in the first embodiment. Therefore, the effect according to this is also obtained in the same manner as in the first embodiment and description thereof will be omitted.

Since the continuously variable transmission of the present invention has a large speed ratio width, the continuously variable transmission has more advantages when applied to an industrial continuously variable transmission requiring a large speed ratio width.

In addition, since the belt transmission portion of the belt transmission continuously covers the entire speed change area of the conventional belt type continuously variable transmission, in order to achieve the low speed to the high speed in the belt speed change portion, the belt speed change portion must cover everything from the deceleration to the speed increase. Therefore, in the related art, when the differential gear is connected, a large reduction ratio is required, which is bad in terms of efficiency. However, in the present invention, the planetary gear system may have a lock-up function capable of further increasing efficiency at high speed while simultaneously selecting output for forward and backward according to mode selection in the planetary gear system, thereby increasing efficiency.

In addition, the conventional belt type continuously variable transmission has a structure in which the planetary gear system reverses at the time of reversing but must obtain a constant speed ratio at the belt transmission. Eventually, both elements should be used, but in the present invention, the structure can be simplified since it can reverse itself in the planetary gear system.

In addition, in the present invention, since the deceleration is performed in the connecting gear system connected between the planetary gear system and the belt shifting unit, there is an advantage in that the gear shifting unit does not have to bear a large output load when adjusting the shifting ratio. Therefore, it has the advantage that can freely achieve the gear shift required by each car.

Furthermore, in the present invention, since the method does not use the power of the belt transmission portion at high speed or backward, it is possible to run quieter than the conventional belt type continuously variable transmission, thereby improving quietness.

As described above, the present invention can provide a continuously variable transmission having a wide speed ratio, a high fuel economy, and excellent durability, and also adopts a mode selection in a planetary gear system without employing a separate configuration for a power transmission shaft to select an operation mode. Because the necessary elements are combined, the structure is simple and inexpensive.

In the above, the present invention has been illustrated and described by way of specific preferred embodiments, but the present invention is not limited to the above-described embodiments, and the general knowledge in the technical field to which the present invention pertains falls within the scope of the present invention. Various changes and modifications can be made by those who have

Claims (9)

A belt transmission unit for continuously changing a speed ratio of the first power input corresponding to the traveling resistance of the output shaft when the first power generated by the engine is input through the first input shaft; A connection gear system for transmitting a second power obtained by increasing torque of the first speed continuously variable through the belt transmission part to a rear end; A planetary gear system for shifting the first power input to the sun gear through the first input shaft and then mixing the second power input from the connecting gear system to the ring gear through the second input shaft as a carrier and transmitting the resultant to the output shaft; And a mode selector for selecting an operation mode of the transmission in combination with the set element of the planetary gear system. The planetary gear system of claim 1, wherein A sun gear connected integrally with the first input shaft; A first planetary pinion gear meshed with the sun gear to receive rotation; A second planetary pinion gear meshed with the first planetary pinion gear, A ring gear meshed with the second planetary pinion gear; It is composed of a carrier that supports the first and second planetary pinion gear and is integrally connected to the output shaft, The mode selector A forward clutch for selectively coupling the second connecting gear and the ring gear to set the forward driving mode; A reverse brake for selectively stopping the ring gear to set in reverse driving mode; A continuously variable transmission comprising a lock-up clutch for selectively integrally coupling a ring gear and a carrier to improve efficiency at high speeds. The continuously variable transmission of claim 2, wherein the forward driving mode couples the forward clutch and separates the reverse brake and the lock-up clutch. 3. The continuously variable transmission according to claim 2, wherein the overdrive mode is set by releasing the reverse brake, releasing the lock-up clutch and engaging the forward clutch with the lock-up clutch engaged. 3. The continuously variable transmission as claimed in claim 2, wherein the reverse driving mode is set by engaging the forward clutch and the reverse brake with the lock-up clutch detached. According to claim 1, wherein the belt transmission portion shaft is integrally connected to the first input shaft and the drive pulley which is variable according to the driving state of the vehicle, the driven pulley receiving the power of the drive pulley, the drive pulley and the driven It consists of a belt connecting the pulley, the width of the groove of the driving pulley and the driven pulley is narrowed, the transmission ratio is determined according to the change in the effective radius that the belt is applied, The connecting gear system includes a first connecting gear integrally connected to a shaft of a driven pulley, a connecting pinion gear supported on a fixed shaft and engaged with the first connecting gear, and a ring gear of the planetary gear system engaged with the connecting pinion gear. A continuously variable transmission comprising: a second connection gear for transmitting power to a low speed gear; wherein the output is decelerated at a predetermined reduction ratio as a second power, and is transmitted to the ring gear through a second input shaft. The continuously variable transmission of claim 1, wherein the first input shaft is rotatably installed in the second input shaft to connect the driving pulley and the sun gear. The continuously variable transmission of claim 1, further comprising a torque converter which receives the first power generated by the engine through an input shaft and transmits the torque converted power to the first input shaft. 9. The continuously variable transmission of claim 8, wherein the torque converter further comprises a lock-up clutch for integrating the pump housing and the first input shaft at high speed rotation between the input shaft and the first input shaft.

Images