KR20040042098A - Hydro-mechanical transmission having two-range - Google Patents

Abstract

PURPOSE: A mechanical hydraulic CVT(Continuously Variable Transmission) having a 2-speed range is provided to simplify the structure of a gear train, enable 3-speed shifting for high-speed driving just by a shift control function, and enable application to a high-power large vehicle although reducing the size of a hydraulic power transmission device. CONSTITUTION: A mechanical hydraulic CVT shifts the engine power transmitted to an input shaft(1) and outputs the shifted engine power to an output shaft(4). The mechanical hydraulic CVT having a 2-speed range comprises a mechanical power transmission device and a hydraulic power transmission device. The mechanical power transmission device comprises a planetary gear part(2) and power transmission gears(26,27,28,29,30). In the mechanical power transmission device, shifting is executed by control of first, second, and third clutches(14,15,16) and forward and backward moving dog clutches(18,17). The hydraulic power transmission device comprises two first hydraulic motor/pumps(20) and one second hydraulic motor/pump(22). The hydraulic power transmission device converts the mechanical power transmitted from the mechanical power transmission device into hydraulic power, converts the converted hydraulic power into mechanical power, and transmits the converted mechanical power to the mechanical power transmission device.

Description

HYDRO-MECHANICAL TRANSMISSION HAVING TWO-RANGE}

The present invention relates to a mechanical hydraulic continuously variable transmission having a two-speed transmission stage, and more specifically, the power of the input shaft transmitted from the engine is separated and transmitted to the mechanical power and the hydraulic power, but the mechanical power input speed and the hydraulic power input speed The present invention relates to a mechanical hydraulic continuously variable transmission having a two speed transmission stage in which a change in power transmission speed and torque is obtained through a continuously variable speed ratio in a speed range of 1: -1, 1: 0, and 1: 1.

In general, the continuously variable transmission may be classified according to its power transmission medium, and the belt type continuously variable transmission using the belt as the power transmission medium transmits power by using a belt connecting the pulley and the pulley.

At this time, a constant tension must be maintained on the belt connecting the pulley and the pulley, and a constant frictional force must be applied between the pulley and the belt to prevent slippage.

Therefore, the conventional belt continuously variable transmission cannot accurately transmit power due to the inevitable sliding between the pulley and the belt, and it is always configured to have a constant tension of the belt regardless of the large or small transmission power, resulting in waste of energy. It is mainly applied to small and medium sized cars because there is a problem such as a difference in electric capacity due to the change of the tension of the belt when switching.

On the other hand, the toroidal type that uses the adhesive frictional force of the oil film formed while the rotating disc and the roller are in contact with each other as a medium for power transmission has the advantage of high efficiency in power transmission and a relatively large power can be transmitted. There are problems in securing durability and special lubricants for generating adhesive friction due to oil film, which are not economically competitive, and they are mainly applied to large passenger cars and small and medium-sized trucks because they can transmit relatively large power. .

In addition, in case of pure hydraulic CVT, high output power can be transmitted under proper torque, and there is an advantage in that it can operate conveniently in stepless speed range. Has a low disadvantage compared to the basic transmission, and is used in a limited number of heavy construction equipment.

In particular, the mechanical hydraulic continuously variable transmission developed to compensate for the low efficiency and the heavy and large volume, which are disadvantages of the purely hydraulic continuously variable transmission, is a mechanical transmission with high efficiency, the continuously variable characteristics, and the pure hydraulic continuously variable transmission capable of high torque output at low speed. It is a transmission developed to apply only advantages.

Therefore, the conventional mechanical hydraulic continuously variable transmission transmits power by using a mechanical power transmission device to increase its efficiency at high speeds, and transmits power through a hydraulic power transmission device when high torque starts or continuously shifts at a low speed. It is structured to be.

However, the conventional mechanical hydraulic CVT can use the size of the hydraulic power transmission device smaller than the hydraulic CVT, but in order to match the required speed and torque of the vehicle, the transmission speed of the mechanical power transmission device is increased and the transmission speed is increased. There are disadvantages such as the complexity of the gear train structure increases, and additional control device is required for proper control of the hydraulic power transmission device for shifting and acceleration during operation.

As a result, the conventional mechanical hydraulic CVT needs to reduce the number of gear shifts of the mechanical power transmission device, reduce the size of the hydraulic power transmission device, and simplify the control method according to the vehicle model to be applied.

The present invention has been made in order to improve such a conventional problem, the number of gear stages to two gears to simplify the structure of the gear train, and to configure a three-speed transmission for high-speed operation only by the shift control function, the hydraulic power transmission device The size of the hydraulic motor and the hydraulic pump can be changed according to the capacity required for each gear stage, so it can be applied to high output large vehicles even if the size of the hydraulic power transmission device is reduced. Its purpose is to provide a mechanical hydraulic continuously variable transmission having a two-speed transmission.

1 is a block diagram illustrating the present invention,

Figure 2 is a block diagram illustrating a power transmission path at the first forward speed of the present invention,

Figure 3 is a block diagram illustrating a power transmission path at the forward two-speed shift of the present invention,

Figure 4 is a block diagram illustrating a power transmission path when the three-speed forward of the present invention,

5 is a configuration diagram illustrating a power transmission path at the reverse shift of the present invention;

6 is a diagram illustrating the connection state of the clutch and the operation state of the hydraulic motor / pump during forward and backward shifts of the present invention.

<Description of the symbols for the main parts of the drawings>

DESCRIPTION OF SYMBOLS 1: Input shaft 2: Planetary gear part 3: Stepless transmission part 4: Output shaft 5: Planetary gear axis 6: First sun gear 7: First planetary gear 8: First carrier 9: First ring gear 10: Second sun gear 11: First 2 planetary gear 12: second carrier 13: second ring gear 14: first clutch 15: second clutch 16: third clutch 17: reverse dog clutch 18: forward dog clutch 19: second intermediate shaft 20: first hydraulic pressure Pump / Motor 21: Valve block 22: Second hydraulic motor / pump 23: First intermediate shaft 24: Brake 25: Input shaft fixed gear 26, 27, 28, 29: Power transmission gear 32: Charging pump

In order to achieve the above object, the present invention comprises a planetary gear unit and a power transmission gear in the mechanical hydraulic continuously variable transmission configured to shift the engine power transmitted to the input shaft and output the output shaft to the first, second, and third clutches. A mechanical power transmission device configured to be shifted by interruption of the forward and backward dog clutch; Composed of two first hydraulic motors / pumps and one second hydraulic motors / pumps, the mechanical power transmitted from the mechanical power transmission device is converted into hydraulic power and then converted into mechanical power to the mechanical power transmission device. It is to provide a mechanical hydraulic continuously variable transmission having a two-speed transmission stage, characterized in that consisting of; hydraulic power transmission device for transmitting.

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

Figure 1 is a block diagram illustrating the present invention, Figure 2 is a block diagram illustrating a power transmission path at the first forward speed of the present invention, Figure 3 is a diagram illustrating a power transmission path at the forward two speed shift of the present invention. 4 is a configuration diagram illustrating a power transmission path in shifting in the state of being directly connected to the third forward engine, that is, the engine of the present invention, and FIG. 5 is a configuration diagram illustrating a power transmission path in the reverse shift of the present invention. 6 is a diagram for explaining the connection state of the clutch and the operation state of the hydraulic motor / pump during forward and backward shifts of the present invention.

The present invention is a mechanical hydraulic continuously variable transmission in which, as illustrated in FIG. 1, after the power input from the engine is transmitted to the input shaft 1, the planetary gear part 2 and the power transmission gear 26, 27, 28, 29, 30 are shown. It is configured to be separated and transmitted through a mechanical power transmission device consisting of a) and a hydraulic power transmission device consisting of two first hydraulic motor / pump 20 and one second hydraulic motor / pump (22).

At this time, each of the power delivered to the mechanical power transmission device and the hydraulic power transmission device is synthesized or separated through appropriate control, and the stepless speed change and power transmission is made.

In addition, in the present invention, in transmitting the driving force transmitted from the engine to the input shaft (1) to the output shaft (4), it is configured to have a simple power transmission structure capable of continuously shifting and shifting in accordance with the driving conditions and necessary power transmission. .

In particular, in the present invention, the speed and torque change during power transmission can be obtained through the continuously variable speed ratio in the speed ratio continuous range of 1: -1, 1: 0 and 1: 1 of the mechanical power input speed and the hydraulic power input speed. It has a power transmission structure.

In addition, the mechanical power transmission device of the present invention is the first planetary gear (7) connected to the input shaft (1), the second planetary gear (11), the first planetary gear (8) connected to the first carrier (8) of the first planetary gear (7) It is composed of a gear train consisting of a first intermediate shaft 23 and a power transmission gear 26, 27, 28, 29, 30 connected to the second carrier 12 of the two planetary gears.

At this time, the mechanical power transmission device is operated as the first and second forward gears of the range of speed and torque required for output by the continuous variable, and the third gear and the reverse gear, which is directly connected to the input shaft (1) to transmit power. .

In addition, clutches 14, 15, 16, 17, 18 and brakes 24 for operating in each of the forward and reverse shift stages are constituted, and suitable for providing sufficient speed and torque according to the driver's driving conditions. Clutch operation control device is configured for the operation of the gear shift stage.

On the other hand, the hydraulic power transmission device of the present invention is configured to transmit power through a hydraulic pump for converting the mechanical power to the hydraulic power, and a hydraulic motor for converting the hydraulic power back to the mechanical power.

Here, by adjusting the variable swash plate of the hydraulic pump and the hydraulic motor from the valve block 21 and the control device, the stepless speed change function required by the driver is controlled by controlling the direction change of the power constantly transmitted in one direction and the speed and torque. Perform.

At this time, in order to optimize the hydraulic power transmission device required for each shift stage, two first hydraulic pumps / motors 20 operate as a pump function and one second hydraulic pump / The motor 22 is operated by the motor function.

In addition, in the second forward shift stage, one second hydraulic pump / motor 22 operates as a pump function and two first hydraulic pumps / motors 20 operate as a motor function.

In the present invention, when shifting the first forward speed is performed, when the power is transmitted to the input shaft 1 according to the driving of the engine as illustrated in FIG. 2, the connected third clutch 16 is connected to transmit power transmission for the forward movement. Done.

At this time, the input shaft fixing gear 25 connected to the input shaft 1 transfers power to the PTO, the charging pump 32 and the reverse dog clutch 17, the reverse dog clutch 17 is connected at the time of shifting forward 1 stage. Power is cut off.

Here, the third clutch 16 is connected so that the driving force of the input shaft 1 drives the planetary gear shaft 5 of the first planetary gear of the planetary gear unit 2, and inputs the input power to the first sun gear 6. Will be delivered.

When the first planetary gear 7 is driven in accordance with the driving of the first sun gear 6, the first ring gear 9 and the first carrier 8 are respectively driven by two separate powers.

In other words, the power transmitted to the first carrier 8 is transmitted to the second carrier 12 to drive the second planetary gear 11 to drive the first intermediate shaft 23 and the first intermediate shaft. In the driving of the 23, the input power is transmitted through the mechanical power transmission path connected only by the gear train and the clutch transmitted to the output shaft 4, and the transmission efficiency of the power transmitted through the mechanical power transmission path is very high.

On the other hand, the input power transmitted to the first ring gear 9 by the first planetary gear 7 drives the power transmission gear 26 and according to the connection of the forward dog clutch 18, the second intermediate shaft ( 19), the power transmitted to the second intermediate shaft 19 is transmitted to the power transmission gear 27 is transmitted to the input shaft of the two first hydraulic motor / pump (20).

At this time, in order to transmit power to the two first hydraulic pump / motor 20, the power transmission gear 27 is composed of two external gear train, the first hydraulic pump / motor 20 is the power transmitted from the input shaft By operating the pump function by converting the mechanical power to hydraulic power to discharge the flow rate.

One second hydraulic motor / pump 22 serves as a motor function to transfer the hydraulic power supplied from the first hydraulic pump / motor 20 to the mechanical power, and the first hydraulic pump of the continuously variable transmission part 3. The valve block 21 installed between the motor 20 and the second hydraulic motor / pump 22 performs a flow control function for changing a speed desired by the driver.

In the present invention, as illustrated in FIG. 2, when the first forward gear is shifted, the swash plate of the first hydraulic pump / motor 20 and the second hydraulic motor / pump 22 is adjusted from -1 to +1 to continuously vary the speed. The driver then controls the speed and torque desired.

In the present invention, the hydraulic pump / motor for performing the hydraulic power transmission and the continuously variable functions in the continuously variable transmission part 3 has two units in the first forward stage to minimize the optimal power transmission and the size of the hydraulic device required for each shift stage. While the first hydraulic pump / motor 20 operates as a pump function, one second hydraulic motor / pump 22 is configured to operate as a motor function.

In addition, the hydraulic power is converted back into the mechanical power by the second hydraulic motor / pump 22 and the transmitted power drives the third intermediate shaft 31, and the driving force of the third intermediate shaft 31 is the second. The clutch 15 is sequentially transmitted to the power transmission gears 28 and 29 in a state where the clutch 15 is not connected.

At this time, the driving force of the power transmission gear 29 is made of the mechanical power and the power synthesis transmitted from the first intermediate shaft 23 to the output shaft 4 through the first clutch 14 connected, the synthesized power is It is transmitted to the output shaft 4 to drive the wheels through the differential and the final deceleration stage.

Therefore, in the forward 1 stage, the power input from the engine is constantly transmitted according to the gear ratio through the mechanical power transmission path, but in the hydraulic power transmission path, the first hydraulic pump / motor 20 of the continuously variable transmission 3 and In the process of performing the pump and motor functions of the second hydraulic motor / pump 22, the speed of the output shaft 4 is continuously controlled from the stop state to the speed required by the first stage at stepless speed under the control of the valve block 21. You can shift.

However, the speed exceeding the maximum speed of the first forward speed is continuously changed while obtaining the necessary speed in the second forward speed by adjusting the gear ratio by changing the power transmission path of the planetary gear unit 2 through the clutch operation.

That is, in the present invention, the two forward stages are driven as two powers while the power input to the engine is transmitted to the planetary gear shaft 5 through the third clutch 16 connected to the input shaft 1 as illustrated in FIG. Delivered separately.

In other words, the engine power transmitted to the planetary gear shaft 5 through the input shaft 1 drives the first sun gear 6 and the second ring gear 13, and the first planetary gear 7 is driven. Power is transmitted to the first intermediate shaft 23 connected to the first and second carriers 8 and 12 to the output shaft 4.

In addition, the power transmitted to the planetary gear shaft (5) is transmitted to the second ring gear 13, the second planetary gear (11) which is engaged with the second ring gear 13 is driven while the second sun gear ( 10), the third intermediate shaft 3 is driven while passing through the power transmission gear 30 and the connected second clutch 15 in sequence.

Here, the driving force of the third intermediate shaft 3 is transmitted to one second hydraulic motor / pump 22 as the input power of the continuously variable transmission part 3 through the brake 24, and the second hydraulic motor / pump ( 22) operates as a pump function by the power transmitted from the third intermediate shaft 3 to convert the mechanical power to hydraulic power to discharge the flow rate.

At this time, the two first hydraulic pump / motor 20 performs a motor function for transmitting the hydraulic power delivered at the flow rate discharged from the second hydraulic motor / pump 22 to the mechanical power, stepless speed change unit (3) The valve block 21 located between the first hydraulic pump / motor 20 and the second hydraulic motor / pump 22 performs a flow rate adjustment function for the speed change desired by the driver.

In particular, in the 2nd forward, as in the 1st forward, the swash plate of the first hydraulic pump / motor 20 and the second hydraulic motor / pump 22 is adjusted from -1 to +1 to continuously vary the speed and torque desired by the driver. The second hydraulic motor / pump 22 operates as a pump function, and the first hydraulic pump / motor 20 operates as a motor function.

When the hydraulic power of the second hydraulic pump / motor 22 is converted into mechanical power and transmitted from the first hydraulic pump / motor 20, the second intermediate shaft 19 is driven through the power transmission gear 27, and moved forward. The dog clutch 18 is connected to drive the power transmission gear 26. Accordingly, the first ring gear 9 is driven, so that the continuously variable transmission unit 3 as a hydraulic power transmission device to the first planetary gear 7 is provided. It passes through and transmits continuously variable power.

The mechanical power transmitted to the first sun gear 6 of the planetary gear part 2 and the hydraulic power transmitted to the first planetary gear 7 through the continuously variable transmission part 3 are combined at the first carrier 8. In this case, it is possible to obtain the speed required in the second stage in accordance with the change in the direction and speed of the continuously variable hydraulic power.

However, the speed exceeding the maximum speed of the two forward stages can be obtained by adjusting the gear ratio by changing the power transmission path of the planetary gear unit 2 through the clutch operation.

At this time, in the present invention by blocking the hydraulic power transmitted to the continuously variable transmission (3) to transmit power purely in the mechanical power transmission path to maintain a high transmission efficiency in the high speed section where the shift is not often required, the change in engine speed Only three forwards are configured to achieve the required speed.

In other words, the driving force of the input shaft 1 is transmitted to the first sun gear 6 of the planetary gear shaft 5 through the connected third clutch 16 as illustrated in FIG. After passing through the first and second carriers 8 and 9 through the first planetary gear 7 in turn, they are transferred to the first intermediate shaft 23 to directly drive the output shaft 4.

Here, by disconnecting the second clutch 15 and the forward dog clutch 18, power transmission to the continuously variable transmission 3 is interrupted, thereby preventing unnecessary power loss due to hydraulic power generation.

Further, in the present invention, since the ratio of the reverse shift during the operation of the entire vehicle for the reverse shift is very low, in order to simplify the shift structure, the power is transmitted only by the hydraulic power transmission path through the continuously variable transmission 3. It is structured.

In other words, if the engine power transmitted to the input shaft 1 is transmitted only through the hydraulic power transmission path as illustrated in FIG. 5, the power transmission efficiency is lower than that of the power transmission with the mechanical power transmission path. To adjust the speed desired by the driver, the swash plate of the first hydraulic pump / motor 20 and the second hydraulic motor / pump 22 is controlled from -1 to +1 to continuously change the speed so that the driver can change the speed within the continuously variable speed ratio. There are advantages to it.

During the reverse shift, the driving force of the input shaft 1 is transmitted to the reverse dog clutch 17 directly through the input shaft fixing gear 25 by disconnection of the third clutch 16, and is connected to the reverse dog clutch 17. It is transmitted to the double intermediate shaft 19.

At this time, the first hydraulic pump / motor 20 is driven by the second intermediate shaft 19 and the power transmission gear 27, and the pump action of the first hydraulic pump / motor 20 is performed by the second hydraulic motor /. It is delivered to the pump 22, the second hydraulic motor / pump 22 drives the third intermediate shaft 31 while operating as a motor function.

Here, the driving force of the third intermediate shaft 31 is transmitted to the power transmission gears 28 and 29 in a state in which the second clutch 15 is not connected, and the driving force of the power transmission gear 29 is connected to the first clutch. It is transmitted to the output shaft 4 through 14 to drive the wheels through the differential and the final deceleration stage.

The present invention can transmit the power required by the vehicle while shifting to the minimum gear stage, and continuously variable speed, unlike the conventional mechanical hydraulic continuously variable transmission, it is possible to operate at high speed with a two-speed shift, which is the minimum shift stage, hydraulic power The unit can be used as both a hydraulic pump and a motor so that three hydraulic pumps / motors can be used for each shift stage, and the first stage uses two hydraulic pumps and one hydraulic motor. Equipped with one hydraulic pump and two hydraulic motors, it is capable of continuously variable speed transmission and power transmission with optimal capacity, and the speed ratio adjustment is made to operate the maximum speed from the first stage to the maximum speed of 50 km that can be driven in the city. As it is possible to apply it to a city bus, there is almost no shift shock, so the vehicle can be operated until the high-speed operation, thereby providing a stable ride for passengers standing in the vehicle. It can provide the effect.

Claims (7)

In the mechanical hydraulic continuously variable transmission configured to shift the engine power transmitted to the input shaft (1) to output to the output shaft (4), The planetary gear unit 2 and the power transmission gears 26, 27, 28, 29, and 30 are provided, and the first, second, and third clutches 14, 15, and 16 are interlocked with the front and rear dog clutches 18 and 17, respectively. A mechanical power transmission device configured to be shifted by; Composed of two first hydraulic motor / pump 20 and one second hydraulic motor / pump 22, by converting the mechanical power transmitted from the mechanical power transmission device to the hydraulic power and then to the mechanical power again A hydraulic power transmission device having a two-speed gear stage characterized in that consisting of; a hydraulic power transmission device for transmitting to the mechanical power transmission device. The method of claim 1, The planetary gear unit 2 may include a first sun gear 6, a first planet gear 7, a first ring gear 9, and a second sun gear of the first intermediate shaft 23 of the planet gear shaft 5. 10) and the second planetary gear 11, the second ring gear 13, the first and second planetary gears (8, 12) are configured to be connected to the first and second planetary gears (7, 11) A mechanical hydraulic continuously variable transmission having a two speed shift stage. The method according to claim 1 or 2, The third clutch (16) is a mechanical-hydraulic continuously variable transmission having a two-speed gear stage that is configured to control the input shaft (1) and the planetary gear shaft (5) during the reverse and forward 1, 2, 3 gear shifts, respectively. The method according to claim 1 or 2, The first clutch (14) is a mechanical-hydraulic continuously variable transmission having a two-speed gear stage is configured to control the first intermediate shaft (23) and the output shaft (4) during the reverse and forward 1, 2, 3 gear shifts, respectively. The method according to claim 1 or 2, The second clutch 15 is configured to control the power transmission gear 30 and the third intermediate shaft 31 which are tooth-coupled with the second sun gear 10 during the reverse, forward 1, 3, and 2 forward gears, respectively. Mechanical hydraulic continuously variable transmission with two speeds. The method of claim 1, The front and rear dog clutch (18, 17) is a mechanical hydraulic continuously variable transmission having a two-speed gear stage that is configured to control the input shaft (1) and the second intermediate shaft (19) in the forward, 1, 2, 3 stage and the reverse shift, respectively. . The method of claim 1, The two first hydraulic motors / pumps 20 and the first hydraulic motors / pumps 22 perform the pump function and the motor function in the first forward and reverse shifts, respectively, and the motor function and the pump in the second forward shifts. A mechanical hydraulic continuously variable transmission having a two speed transmission stage, characterized in that it is configured to perform a function.