KR102251325B1 - Power take-off unit for 4 wheel driving vehicle - Google Patents

Abstract

A secondary transmission of a four-wheel drive vehicle that transmits power transmitted from an engine and a transmission to a rear wheel through a propulsion shaft when switching from two-wheel drive to four-wheel drive, comprising: an input shaft to which the power of the transmission is input; An output shaft receiving power from the input shaft; And a switching means provided between the input shaft and the output shaft to transmit the power of the input shaft to the output shaft, and having a shock removing means for removing an impact generated from a difference in input/output speed; Is introduced.

Description

Auxiliary transmission for 4 wheel drive vehicles {POWER TAKE-OFF UNIT FOR 4 WHEEL DRIVING VEHICLE}

The present invention relates to an auxiliary transmission for a four-wheel drive vehicle for preventing damage to a switching device actuator due to an impact caused by an input/output speed difference when switching from a two-wheel drive mode to a four-wheel drive mode.

Typically, a two-wheel drive vehicle is classified into a front engine rear drive (FR) type or a front engine front drive (FF) type according to an engine and transmission mounting position and an actual driving wheel position.

Since the driving force required when a two-wheel drive vehicle is running varies greatly depending on road conditions and driving speed, etc. in the state where passengers and cargo are loaded, a device that changes the torque between the engine and the driving wheel is required to cope with this. In this way, a device for changing torque is called a transmission, and the transmission can be divided into a manual transmission and an automatic transmission.

The transmission including the above-described manual transmission and automatic transmission is generally configured to be capable of shifting in 6 gears of 1st, 2nd, 3rd, 4th, 5th, and reverse gear. In the 4WD) vehicle, in addition to the configuration for shifting in six stages, a secondary transmission for four-wheel drive is additionally installed.

6 is a block diagram schematically showing a vehicle equipped with an auxiliary transmission for a conventional four-wheel drive vehicle. Looking at the flow of power through the drawing, an engine 100 for generating power and a transmission 200 for transmitting the power of the engine 100 to the front wheels 800 and the rear wheels 400 are provided. The transmission 200 is provided with a sub transmission 1000 consisting of an input shaft 500, a switching means 900, and an output shaft 600, so that the power input through the transmission 200 is transferred to the input shaft of the auxiliary transmission 1000. The power is transmitted to the output shaft 600 through 500, and the power transmitted to the output shaft 600 passes through the propulsion shaft 300 through the pinion gear 700 coupled to the output shaft 600 at 90 degrees, and the rear wheel 400 is It is delivered as.

However, in the conventional case, when switching from the two-wheel drive mode to the four-wheel drive mode, the power is transmitted to the rear wheel 400 through the auxiliary transmission 1000, and an impact is generated (blocking, blocking) due to the difference in input/output speed. There has been a problem that damage to the actuator 950 in the switching means 900 occurs.

The matters described as the background art are only for enhancing an understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art.

KR 20-0287042 Y1

The present invention has been proposed to solve this problem, and a sub transmission for a four-wheel drive vehicle capable of securing sufficient switching power while preventing an impact due to an input/output speed difference when switching from a two-wheel drive mode to a four-wheel drive mode is generated. It has its purpose to provide.

The auxiliary transmission for a four-wheel drive vehicle according to the present invention for achieving the above object is a sub transmission of a four-wheel drive vehicle that transmits power transmitted from the engine and transmission to the rear wheel through a propulsion shaft when switching from two-wheel drive to four-wheel drive. , An input shaft into which power of the transmission is input; An output shaft receiving power from the input shaft; And a switching means provided between the input shaft and the output shaft, transmitting the power of the input shaft to the output shaft, and having a shock removing means for removing an impact generated from a difference in input/output speed.

The switching means may include a sleeve provided on the input shaft; A shift fork for shifting the sleeve; An actuator providing a driving force to the shift fork; A lead screw connected to the actuator to convert rotational motion into linear motion; And an impact removing means double wound on the outside of the lead screw.

The impact removing means is composed of a plurality of coil springs, an inner coil spring provided along an outer circumferential surface of the lead screw, and an outer coil spring provided radially spaced apart from the inner coil spring by a predetermined distance, and the coil spring is It may be provided to form a ply.

The impact removing means is a plurality of coil springs, provided by forming plies along the outer circumferential surface of the lead screw, and the inner coil spring may protrude further to both sides in the longitudinal direction than the outer coil spring.

The impact removing means is a plurality of coil springs, provided by forming a ply along the outer circumferential surface of the lead screw, and the inner coil spring may have a smaller number of turns than the outer coil spring.

The impact removing means is a plurality of coil springs, provided by forming plies along the outer circumferential surface of the lead screw, but the inner coil spring may have a smaller pitch than the outer coil spring.

The impact removing means is a plurality of coil springs, provided by forming a ply along the outer circumferential surface of the lead screw, and the outer coil spring is installed to protrude further toward the actuator side than the inner coil spring, and the rotation of the actuator causes the When the leadscrew moves, the outer coil spring may be pressed before the inner coil spring.

The impact removing means is a plurality of coil springs, formed by forming a ply along the outer circumferential surface of the lead screw, and a support member for supporting the end of the coil spring is provided at the end of the coil spring, so that when the lead screw moves, the The support member is pressed so that the coil spring can be compressed.

A fork shaft is provided between the lead screw and the shift fork to assist the movement of the shift fork.

According to the auxiliary transmission for a four-wheel drive vehicle having the structure as described above, there is an effect of removing the coupling impact between the input shaft and the output shaft when switching from the two-wheel drive mode to the four-wheel drive mode. Moreover, by simplifying the structure, there is an effect of reducing weight and cost. In addition, there is an advantage in that the impact can be alleviated when thrust is generated by the dog clutch back taper of the input shaft and the sleeve during the actuator release operation of the switching means.

In addition, when the electronic auxiliary transmission is applied, the switching means can contribute to the improvement of fuel economy of the vehicle by blocking the rotational loss of the propulsion shaft by performing the function of engaging and releasing the input shaft and the output shaft by the actuator.

1 is a view showing an auxiliary transmission for a four-wheel drive vehicle according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, illustrating the start of switching from a two-wheel drive mode to a four-wheel drive mode.
Figure 3 is a view showing in detail B of Figure 2;
FIG. 4 is a cross-sectional view taken along line AA of FIG. 1, showing the completion of switching from a two-wheel drive mode to a four-wheel drive mode.
Figure 5 is a view showing the detail C of Figure 4;
6 is a block diagram schematically showing a vehicle equipped with an auxiliary transmission for a four-wheel drive vehicle.
7 is a graph showing a reduction in impact force when a conventional single spring is mounted.
8 is a graph showing a reduction in impact force when the impact removing means of the present invention is mounted.

Hereinafter, an auxiliary transmission for a four-wheel drive vehicle according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a view showing an auxiliary transmission for a four-wheel drive vehicle according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1, showing a start of switching from a two-wheel drive mode to a four-wheel drive mode, and FIG. 3 is a view showing B of FIG. 2 in detail. FIG. 4 is a cross-sectional view taken along line A-A of FIG. 1, illustrating completion of switching from a two-wheel drive mode to a four-wheel drive mode, and FIG. 5 is a view showing C in detail. In addition, FIG. 6 is a block diagram schematically showing a vehicle equipped with a sub transmission for a four-wheel drive vehicle, FIG. 7 is a graph showing a reduction in impact force when a conventional single spring is mounted, and FIG. 8 is a shock removing means of the present invention ( 910,920) is a graph showing the reduction in impact force when installed.

In the case of a vehicle capable of implementing both the two-wheel drive mode and the four-wheel drive mode, the engine 100, the transmission 200, the auxiliary transmission 1000, the propulsion shaft 300, the front wheel 800, as shown in FIG. ) And a rear wheel 400. The present invention relates to a switching means 900 provided in the auxiliary transmission 1000 among the auxiliary transmissions 1000, and when the input shaft 500 and the output shaft 600 are fastened when the switching means 900 is operated, the It relates to a shock removing means (910,920) for removing the shock generated from the difference in rotational speed between the input shaft 500 and the output shaft 600, and the shock generated by the difference in input/output speed when switching from the two-wheel drive mode to the four-wheel drive mode It relates to a configuration capable of preventing damage to the actuator 950 of the switching means 900 and securing a switching force.

In the auxiliary transmission for a four-wheel drive vehicle according to a preferred embodiment of the present invention, when switching from two-wheel drive to four-wheel drive, the power transmitted from the engine 100 and the transmission 200 is transferred to the rear wheel 400 through the propulsion shaft 300. In the auxiliary transmission of a four-wheel drive vehicle that transmits, the input shaft 500 to which the power of the transmission 200 is input; An output shaft 600 receiving power from the input shaft 500; And a shock removing means (910,920) provided between the input shaft 500 and the output shaft 600 to transmit the power of the input shaft 500 to the output shaft 600, but to remove an impact generated from a difference in input/output speed. It includes; switching means 900 provided. The output shaft 600 may be a ring gear. A fork shaft 980 is provided between the leadscrew 960 and the shift fork 940 to assist the movement of the shift fork 940.

In addition, the switching means 900, a sleeve 930 provided on the input shaft 500; A shift fork 940 for shifting the sleeve 930; An actuator 950 providing a driving force to the shift fork 940; A lead screw 960 connected to the actuator 950 to convert a rotational motion into a linear motion; And impact removing means (910,920) double wound on the outside of the leadscrew (960). The actuator 950 may be a motor.

It will be described in detail through FIGS. 2 to 5.

In the two-wheel drive mode, the input shaft 500 and the output shaft 600 are not connected so that the power of the transmission 200 is not transmitted to the rear wheel 400. However, when driving in the four-wheel drive mode is required, the input shaft 500 and the output shaft 600 are connected so that the power of the engine 100 is transmitted to the output shaft 600 through the input shaft 500, and the The power transmitted to the output shaft 600 is transmitted to the rear wheels 400 through the propulsion shaft 300 by the pinion gear 700 connected to the output shaft 600.

Accordingly, in order to transmit power to the rear wheels 400 when switching from the two-wheel drive mode to the four-wheel drive mode as described above, the sleeve 930 is connected to the input shaft 500 and the output shaft 600. The sleeve 930 is shifted so that the input shaft 500 and the output shaft 600 are synchronized by the shift fork 940 pressed by the leadscrew 960 moved by the drive of the actuator 950. It becomes.

In addition, during the above operation, the shock removal means 910 and 920 are provided to prevent an impact due to a difference in speed between the input shaft 500 and the output shaft 600. The impact removing means 910 and 920 are double wound on the outside of the leadscrew 960. Support members 970 on which the impact removing means 910 and 920 are supported may be provided at both ends of the impact removing means 910 and 920. The impact removal means 910 and 920 will be described in detail through FIGS. 1 to 5.

The impact removing means 910 and 920 may be a plurality of coil springs. The impact removing means (910,920) is an inner coil spring 910 provided along the outer circumferential surface of the lead screw 960 and an outer coil spring provided spaced apart from the inner coil spring 910 by a predetermined distance in the radial direction ( Consisting of 920), the coil spring is provided to form a ply (double) in a radial direction rather than a longitudinal direction. Accordingly, there is an advantage in that the amount of shock absorption can be increased compared to the conventional shock removing means 910 and 920 being composed of a single coil spring.

In addition, the outer coil spring 920 may be installed to protrude further to both sides in the longitudinal direction than the inner coil spring 910 . Therefore, when the support member 970 is pressed due to the movement of the lead screw 960, the outer coil spring 920 is compressed first, and after a certain amount of compression is performed, the inner coil spring 910 is also compressed. As a result, the fastening force is increased by the compressive energy absorbed by the inner coil spring 910 and the outer coil spring 920 so that the shift fork 940 can better shift the sleeve 930, so that the It is possible to quickly and stably fasten the input shaft 500 and the output shaft 600 while removing the impact caused by the difference in speed between the input shaft 500 and the output shaft 600.

In addition, the impact removing means (910,920) may be configured to have a smaller number of turns than the outer coil spring in the inner coil spring, and the inner coil spring 910 has a smaller pitch than the outer coil spring (920). It can also be configured.

In particular, as described above, in order to cause the outer coil spring 920 to be compressed earlier than the inner coil spring 910, the outer coil spring 920 is the actuator 950 than the inner coil spring 910. It is installed so as to protrude further to the side. Therefore, when the lead screw 960 is moved by the rotation of the actuator 950, the outer coil spring is pressed before the inner coil spring, so that when the input shaft 500 and the output shaft 600 are fastened, the input shaft 500 ) And the output shaft 600 to remove the impact due to the speed difference, there is an effect of increasing the fastening force between the input shaft 500 and the output shaft 600.

In addition, a support member 970 is provided at an end of the coil spring to support the end of the coil spring. Accordingly, when the leadscrew 960 is moved, the support member 970 is pressed to compress the inner coil spring 910 and the outer coil spring 920. In the opposite case, when the lead screw 960 is moved, the support member 970 is depressed and the inner coil spring 910 and the outer coil spring 920 are decompressed. The support member 970 may be provided in the shift fork 940.

7 is a graph showing a reduction in impact force when a conventional single spring is mounted, and FIG. 8 is a graph showing a decrease in impact force when the impact removing means 910 and 920 of the present invention are mounted. Referring to Figures 7 to 8, when a conventional single spring is mounted, the first impact force decrease due to the fastening of the input shaft 500 and the output shaft 600 appears at point D (about 8), whereas the present invention When the double coil spring, which is the impact removing means 910 and 920 of, is provided, the point at which the initial impact force decrease occurs is point E (about 4), and it can be seen that the effect of reducing the impact force according to the fastening is remarkable.

Therefore, the auxiliary transmission for a four-wheel drive vehicle as described above has the effect of reducing weight and cost by removing the impact of the coupling between the input shaft 500 and the output shaft 600 and simplifying the structure when switching from the two-wheel drive mode to the four-wheel drive mode. have. In addition, there is an advantage of mitigating the impact when thrust is generated by the dog clutch back taper of the input shaft 500 and the sleeve 930 during the releasing operation of the actuator 950 of the switching means 900.

In addition, when the electronic auxiliary transmission 1000 is applied, the switching means 900 blocks the rotational loss of the propulsion shaft 300 by performing the fastening and releasing function of the input shaft 500 and the output shaft 600 by the actuator 950. It will be able to contribute to improving the fuel economy of the vehicle.

Although the present invention has been shown and described in connection with specific embodiments, it is in the art that the present invention can be variously improved and changed within the scope of the technical spirit of the present invention provided by the following claims. It will be obvious to those of ordinary skill.

100: engine 200: transmission
300: propulsion shaft 400: rear wheel
500: input shaft 600: output shaft
700: pinion gear 800: front wheel
900: switching means 910: inner coil spring
920: outer coil spring 930: sleeve
940: shift fork 950: actuator
960: lead screw 970: support member
980: fork shaft 1000: sub transmission

Claims (9)

In the secondary transmission of a four-wheel drive vehicle that transmits power transmitted from an engine and a transmission to a rear wheel through a propulsion shaft when switching from two-wheel drive to four-wheel drive,
An input shaft to which power of the transmission is input;
An output shaft receiving power from the input shaft; And
Including; a switching means provided between the input shaft and the output shaft, which transmits the power of the input shaft to the output shaft, and has a shock removing means for removing the shock generated from the input and output speed difference;
The switching means,
A sleeve provided on the input shaft;
A shift fork for shifting the sleeve;
An actuator providing a driving force to the shift fork;
A lead screw connected to the actuator to convert rotational motion into linear motion; And
Consists of; impact removing means double wound on the outside of the leadscrew,
The impact removing means is composed of a plurality of coil springs, an inner coil spring provided along an outer circumferential surface of the lead screw, and an outer coil spring provided radially spaced apart from the inner coil spring by a predetermined distance, and the coil spring is A secondary transmission for a four-wheel drive vehicle, characterized in that provided to form a fold. delete delete The method according to claim 1,
The impact removing means is a plurality of coil springs, provided by forming a ply along the outer circumferential surface of the lead screw, wherein the inner coil spring protrudes further to both sides in the longitudinal direction than the outer coil spring. Transmission. The method according to claim 1,
The impact removing means is a plurality of coil springs, provided to form a fold along the outer circumferential surface of the lead screw, wherein the inner coil spring has a smaller number of turns than the outer coil spring. The method according to claim 1,
The shock removing means is a plurality of coil springs, provided to form a fold along the outer circumferential surface of the lead screw, wherein the inner coil spring has a smaller pitch than the outer coil spring. The method according to claim 1,
The impact removing means is a plurality of coil springs, provided by forming a ply along the outer circumferential surface of the lead screw, and the outer coil spring is installed to protrude further toward the actuator side than the inner coil spring, and the rotation of the actuator causes the An auxiliary transmission for a four-wheel drive vehicle, characterized in that the outer coil spring is pressed before the inner coil spring when the lead screw is moved. The method according to claim 1,
The impact removing means is a plurality of coil springs, formed by forming a ply along the outer circumferential surface of the lead screw, and a support member for supporting the end of the coil spring is provided at the end of the coil spring, so that when the lead screw moves, the A secondary transmission for a four-wheel drive vehicle, characterized in that the support member is pressed to compress the coil spring. The method according to claim 1,
A fork shaft is provided between the lead screw and the shift fork to assist the movement of the shift fork.

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