KR20160128041A - Transmission of agriculture vehicle - Google Patents

Abstract

A transmission of an agricultural working vehicle is disclosed. According to an embodiment of the present invention, the transmission of an agricultural working vehicle comprises: a first shifting unit for forward or backward gear shifting and primary shifting of multiple gears; and a second shifting unit performing secondary shifting to increase and decrease the speed of forward or backward power which is primarily shifted and output by the first shifting unit. Therefore, the present invention allows multiple shifting gears and widely shifts the gear from the low-speed gear to the high-speed gear without increasing the horizontal length of the transmission.

Description

[0001] Transmission of agriculture vehicle [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission device for an agricultural work vehicle, and more particularly, to a shift device for an agricultural work vehicle having a configuration in which a plurality of hydraulic clutches operated by hydraulic pressure are applied to increase the width of a shift range.

The agricultural work vehicle, called 'Tractor', is structurally similar to a general automobile, but it is equipped with a powerful engine, so it is mainly used as a tractor with strong pulling force, and is used for cultivation. Various types of working machines can be selectively attached or detached.

In order to improve the work efficiency through the agricultural work vehicle, the width of the shift range should be wide so as to optimally adjust the traveling speed and the rotation speed of the power take-off shaft (PTO shaft, Power Take Off) in accordance with the soil of the work part. Therefore, a complex type of transmission having a wider range of speeds is adopted for agricultural work vehicles, unlike ordinary vehicles.

FIG. 1 shows a mission combination (shift combination) applied to a conventional agricultural work vehicle.

Referring to FIG. 1, the mission combination of a conventional agricultural work vehicle is largely composed of a mission part 1 and a rear car part 6. The mission portion 1 includes a shuttle transmission portion 2 related to forward and backward shifts, a peripheral speed portion 3 and a negative speed change portion 4 for implementing a wide range of speeds, a front wheel drive portion 5 for a double speed turn and front wheel drive And the rear differential section 6 appropriately distributes the power shifted by the mission section 1 to the left and right rear wheels.

The shuttle transmission portion 2 constituting the mission portion 1 is a hydraulic clutch type in which selective power connection is implemented by pressurized oil flow allowed by the operation of a driver lever and the peripheral speed portion 3 is a synchronous type four- Gears. The auxiliary transmission portion 4 is configured such that a plurality of pairs of gears having different gear ratios can be selectively engaged while being moved left and right by lever operation.

The front wheel drive unit 5 is applied with a hydraulic clutch system in the same manner as the shuttle transmission unit 2 and various components constituting the mission unit 1 and the rear drive unit 6 are mounted in a transmission case 8 And the oil is filled in the transmission case 8 as a lubricant which smoothly transmits power between the gears and smoothly rotates the shaft and reduces friction and abrasion between the parts.

On the other hand, the auxiliary speed-change section 4 functions to shift once again by receiving the transmission power that has undergone the primary speed-change while passing through the peripheral speed section 3, and finally, through the auxiliary speed- The transmission power in which the rotational direction and the rotational speed are determined is provided to the rear differential section 6 and appropriately distributed to the left and right rear wheels which become drive wheels via the rear differential section 6. [

In the figure, reference numeral 7 denotes a PTO drive unit for drawing engine power out of the gas to utilize the power output from the engine as a power for driving a working machine.

However, in the mission combination of the conventional agricultural work vehicle, the peripheral speed device and the auxiliary speed device, which perform the shifting in relation to the actual running speed, employ a manual shift mechanism that shifts the shifter by operating the lever , There is a problem that the structure is very complicated and noises are generated during shifting operation, and there is a problem that operational fatigue is accumulated.

Further, there is a problem in that the mobility and the stability are inferior due to the large shift shock at the time of shifting. To improve this, there is considered a method of increasing the number of shift stages by applying more gears. However, in order to increase the shift speed, And in this case, it is accompanied with a difficulty in mounting the vehicle, which leads to deterioration of the fuel economy due to the weight of the vehicle.

Korean Patent No. 10-0988155 (registered on Oct. 10, 2010)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shift device for an agricultural work vehicle capable of facilitating shifting, capable of providing a shifting member, and capable of alleviating a shift shock upon shifting.

Another object to be solved by the present invention is to provide a hydraulic control apparatus capable of achieving multiple shafting of the speed change stages without increasing the length in the forward and backward direction of the speed change device and thereby permitting the shift from a low speed to a high speed, And to provide a shift device of a car.

As a means for solving the problem, the present invention provides a vehicle including: a first shift portion for forward and reverse shifting and first-speed shifting of a plurality of stages; And a second speed change portion disposed rearward of the first speed change portion and performing a second speed change for decelerating or decelerating the power that is firstly shifted and whose rotational direction is determined by the first speed change portion, The transmission portion is constituted by a combination of a plurality of hydraulic clutches and transmission gears arranged in parallel and the second transmission portion includes a hydraulic clutch disposed on the same axis as the first axis of the first transmission portion connected to the engine output shaft And a speed change mechanism for the agricultural work vehicle.

In the present invention, the number of primary shift stages by the first shift portion may be four, and the number of secondary shift stages by the second shift portion may be two.

And the hydraulic clutch constituting the first transmission portion includes: a first clutch on the first shaft connected to the engine output shaft; A second clutch disposed on a second shaft parallel to the first shaft and operatively connected to the first clutch; And a third clutch disposed on a third axis parallel to the first axis and independent from the second clutch and connected to the first clutch so as to be interlocked with the first clutch, 1, a second gear; Third and fourth gears on a second axis meshing with the first and second gears; A fifth gear provided at the second axial end portion; And sixth and seventh gears on the third axis that rotate in engagement with the fourth and fifth gears.

At this time, the clutch retainers of the first, second, and third clutches can be configured to be rotatable relative to the corresponding axes (first, second, and third axes).

Preferably, the first gear and the second gear are disposed respectively in front of and behind the first clutch, the third gear and the fourth gear are disposed respectively in front of and behind the second clutch, The gear may be disposed behind the third clutch.

Here, the first, fourth, fifth, and seventh gears are integrally rotated with the corresponding shafts (first, second, and third shafts), and the second, third, Second, and third axes).

The second speed change unit applied to the present invention includes: a high speed short term unit to which a power whose rotational direction is determined by the first speed change unit and is primarily shifted is input; An intermediate shaft having an intermediate gear that is parallel to an axis of the high-speed gear and is always rotated by engaging with the high-speed gear; A low-speed short-range gear which is always rotated by being meshed with an intermediate gear on the other intermediate shaft of the part engaged with the high-speed short-term gear; And a fourth shaft disposed coaxially with the first shaft so as to be rotatable integrally with each other, wherein one of the gears between the high-speed short-term gear and the low-speed gear is connected to the fourth shaft for power transmission And a high / low clutch of a planetary hydraulic clutch structure.

Further, the present invention may further include: a sub shift portion disposed rearward of the second shift portion and shifting the output of the second shift portion again to final output.

At this time, the auxiliary speed change portion may be a synchromesh type manual transmission structure.

According to the transmission according to the embodiment of the present invention, a plurality of hydraulic clutches operated by hydraulic pressure are applied, and compared with the conventional mechanical configuration in which the shifter is shifted to change the number of shift stages, the operational fatigue in shifting operation can be extremely reduced So that it is easy to operate and it is possible to provide convenience of operation with high degree of satisfaction.

Further, mobility and stability can be ensured by reducing the impact of the shift shock, and a plurality of hydraulic clutches are arranged in parallel to realize a transmission, thereby achieving a multi-step transmission gear ratio without increasing the length of the transmission in the front- And has the effect of enabling traveling or operation at a more optimized speed that meets the conditions during traveling or work.

1 is a structural view of a mission combination (shift combination) of a conventional agricultural work vehicle;
2 is a schematic diagram of a speed change device for an agricultural work vehicle according to an embodiment of the present invention.
3 to 10 are views showing an operating state of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.

2 is a schematic view of a shift device of an agricultural work vehicle according to an embodiment of the present invention.

Referring to FIG. 2, the transmission according to the embodiment of the present invention includes a first transmission portion 20 and a second transmission portion 30 disposed behind the first transmission portion 20. The first transmission portion 20 changes the rotational direction of the power output from the engine (forward / backward shift) and outputs the rotational speed of the second transmission portion 30 at a proper rotational speed in accordance with the selected gear ratio selected by the driver. The forward or reverse direction power that has been shifted first is accelerated or decelerated again.

The first transmission portion 20 is constituted by a combination of a plurality of hydraulic clutches and transmission gears. Each of the hydraulic clutches is a known double-pack type hydraulic multi-plate clutch in which a pair of front and rear clutches are selectively or simultaneously connected by hydraulic pressure, and the first clutch 22, the second clutch 24, The transmission gears 211, 213 231, 233, 235, 251 and 253 are constituted by the shafts 21, 23 and 25 to which the first, second and third clutches 26 are attached So as to be able to transmit power.

The first clutch 22 is provided on the first shaft 21 connected to the engine output shaft and is provided on the second shaft 23 parallel to the first shaft 21 and the second shaft 22 on the third shaft 25, A clutch 24 and a third clutch 26 are provided, respectively. The outer surface of the clutch retainer 220 of the first clutch 22 and the gear of the outer surface of the clutch retainer 240 of the second clutch 24 interlock with each other and the outer surface of the clutch retainer 220 of the third clutch 26, And is engaged with the outer surface gear of the clutch retainer (220) of the first clutch (22).

The clutch retainer 240 of the second clutch 24 rotates by the clutch retainer 220 of the first clutch 22 and the clutch retainer 240 of the second clutch 24 rotates in accordance with the clutch connection combination of each clutch, The clutch retainer 220 of the first clutch 22 is rotated by the clutch retainer 220 of the first clutch 22 and the retainer of the third clutch 26 is rotated by the clutch retainer 220 of the first clutch 22, 4 stages).

Specifically, the transmission gear includes two first and second gears 211 and 213 provided on the first shaft 21 and two first and second gears 211 and 213 provided on the first and second shafts 21 and 213, Two third and fourth gears 231 and 233 provided on the two shafts 23 and a fifth gear 235 disposed at the end of the second shaft 23 for finally outputting the power shifted first, And sixth and seventh gears 251 and 253 on the third shaft 25 rotating in engagement with the fourth and fifth gears 233 and 235.

The first gear 211 and the second gear 213 are respectively disposed on the first shaft 21 in front of and behind the first clutch 22 with the first clutch 22 interposed therebetween, The second gear 213 is integrally rotatably provided on the first shaft 21 together with the first hub 222 of the first clutch 22, 2 hub 224 so as not to be constrained to the rotation of the first shaft 21. [

The third gear 231 and the fourth gear 233 are respectively disposed on the second shaft 23 on the front and rear sides of the second clutch 24 and the third gear 231 is disposed on the second shaft 24, And the fourth gear 233 is rotatably disposed on the second shaft 23 together with the second hub 244 of the second clutch 24 and is rotatably disposed on the second shaft 23 together with the first hub 242 of the second clutch 24, As shown in Fig. The fifth gear 235 is also provided at the rear end of the second shaft 23 so as to be rotatable integrally therewith.

The sixth gear 251 and the seventh gear 253 are arranged at a predetermined interval on the third shaft 25 behind the third clutch 26 and the sixth gear 251 is disposed on the third shaft 25 26 is rotatably provided with respect to the third axis 25 together with the second hub of the third clutch 26 and the seventh gear 253 is provided integrally with the first hub of the third clutch 26 on the third shaft 25 And is normally held in engagement with the fifth gear 235.

The second transmission portion 30 is constituted by a high-speed gear 301 and a low-speed gear 303, a fourth shaft 35 rotatably provided with the low-speed gear 303, (33) and a high / low clutch (32) between the high speed gear (301) and the low speed gear (303). The high speed gear 301 is rotated by the primary shifted gear whose rotation direction is determined by engaging with the fifth gear 235 and the low speed gear 303 is rotated by the power that bypasses the intermediate shaft 33 .

The intermediate shaft 33 has a constant engagement structure with the side of the high speed stage gear 301 through the first intermediate gear 331 so that the intermediate shaft 33 rotates together when the high speed stage gear 301 rotates, A second intermediate gear 333 is integrally rotatably provided at the rear end of the intermediate shaft 33 opposite to the first intermediate gear 331 engaged with the high speed gear 301, The gear 303 is engaged and constantly rotated.

The high / low clutch 32 is a known double-pack type hydraulically actuated multi-plate which is provided in a pair of front and rear hydraulic clutches to perform selective power connection among the high speed gear 301 side and the low speed gear 303 side. And a clutch retainer 320 having a plurality of clutch plates on its inner side is arranged to be rotatable integrally with a fourth shaft 35 on the same axis as the first shaft 21. [

The high speed short side hub 322 of the high / low clutch 32 is rotatably provided on the rear side of the first shaft 21 together with the high speed stage gear 301 with respect to the first shaft 21, The hub 324 is disposed rotatably with respect to the fourth shaft 35 at the front end of the fourth shaft 35. With such a structure, the high / low clutch 32 is engaged with the high speed stage gear 301, The fourth shaft 35 does not rotate when the clutch is in the neutral state in which it is not connected to either of the first shaft 303 and the second shaft 303. [

The first intermediate gear 331 engaged with the high speed gear 301 is larger in diameter than the high speed gear 301 so that the rotational force of the high speed gear 301 is transmitted to the first intermediate gear 331 And the second intermediate gear 333 in the coaxial phase is reduced in diameter as compared with the low speed gear 303 and the power is inputted to the low speed gear 303 by bypassing the intermediate shaft 33 Lt; / RTI >

The fifth gear 235 finally outputs the primary shift power by the first speed change section 20 and at this time the diameter of the fifth gear 235 is larger than that of the high speed stage gear 301, The rotational speed is increased in the process of inputting to the high speed gear 301 and the increased power is transmitted to the fourth shaft 35 via the high / low clutch 32 in accordance with the operating direction of the high / Or transmitted to the fourth shaft 35 at a reduced number of revolutions bypassing the intermediate shaft 33.

When the high / low clutch 32 is operated in the direction to connect the high speed gear 301 and the fourth shaft 35, the shift power by the first speed change portion 20 is transmitted through the high speed gear 301 When the low speed gear 303 and the fourth shaft 35 are operated in the direction in which the low speed gear 303 and the fourth shaft 35 are connected to each other, Is decelerated by bypassing the shaft 33 and is transmitted to the fourth shaft 35 via the high / low clutch 32.

Reference numeral 280 in the drawing denotes a PTO connection gear for connecting a PTO shaft (not shown) for taking out the engine power to the outside in a powertransmissible manner. Reference numeral 40 is disposed at the rear of the second transmission portion 30, And transmits the power output through the fourth shaft 35 of the transmission 30 to the drive shaft connected to the wheels once again at a speed suitable for operation or running.

The auxiliary speed change section 40 is connected to the output shaft 41 on the coaxial line with the fourth shaft 35, the intermediate shaft 45 parallel to the output shaft 41, and the output shaft 41 and the intermediate shaft 45, A plurality of gears g1 and g2 that are provided so as to engage with each other and a plurality of shifters 42 and 44 that move along the output shaft 41 to connect the gear pair and the output shaft 41 in power- And may be a synchromesh type manual transmission structure.

Since the auxiliary transmission portion of the synchronous engagement structure is the same as the auxiliary transmission portion of the known structure already applied to the agricultural work vehicle, a detailed description thereof will be omitted.

The power transmission process performed through the transmission according to the embodiment of the present invention will now be described with reference to the operational state diagrams of FIGS. 3 to 12. FIG.

In the following description of the operating state of the present invention, a detailed description of the third-speed shifting performed through the auxiliary shifting portion corresponding to the known structure will be omitted, and the first shifting portion Only shifts realized by various connection combinations of the hydraulic clutches constituting the transmission portion and the second transmission portion will be described.

3 to 6 are views showing the connection state and power flow of the clutches in the forward direction high-speed shifting.

3 to 6, the forward-direction high-speed shifting is established in a state where the high / low clutch 32 of the second transmission portion 30 is connected to the high-speed gear 301 side and fixed, (Fig. 3) of the second clutch 24 constituting the transmission portion 20 (Fig. 3), the bidirectional simultaneous connection of the first clutch 22 (Fig. 6), the first clutch 22 and the second clutch 24 (Fig. 4 and Fig. 5) in which the connection directions of the two terminals are opposite to each other.

3, which is a simultaneous bidirectional connection of the second clutch 24, the engine power is transmitted through the first gear 211 and the third gear 231 to the second- Speed gear 301 of the second speed change section 30 through the second shaft 23 and the fifth gear 235 via the second clutch 24, And is outputted through the fourth shaft 35 directly from the gear 301 to the high / low clutch 32. [

The clutches (the first and third clutches 22 and 26) other than the above-described second clutch 24 among the clutches constituting the first transmission portion 20 in the forward direction first high-speed shifting as shown in Fig. The clutch retainer 220 of the first clutch 22 and the clutch retainer 260 of the third clutch 26 are rotated by the rotation of the second clutch 24, No power is transmitted.

4 is implemented by connecting the second clutch 24 to the third gear 231 side and connecting the first clutch 22 to the second gear 213 side. In this case, The engine power is transmitted through the first gear 211, the third gear 231, the second clutch 24, the first clutch 22, the second gear 213, the fourth gear 233, And is transmitted to the high speed stage gear 301 of the second speed change section 30 through the fifth gear 235 and is transmitted to the fourth shaft 35 directly from the high speed stage gear 301 via the high / Lt; / RTI >

4, the clutch retainer 260 of the third clutch 26 is rotated by the rotation of the clutch retainer 220 of the first clutch 22, but idle because it is in the neutral state And does not affect the rotation of the sixth gear 251 and the seventh gear 253 on the third shaft 25. In FIG. 4, the sixth gear 251 and the seventh gear 253 simply rotate at different speeds by the fourth gear 233 and the fifth gear 235.

5 is implemented by connecting the first clutch 22 to the first gear 211 side and the second clutch 24 to the fourth gear 233 side, and in this case, The engine power is transmitted from the first clutch 22 to the second shaft 23 through the second clutch 24 and is transmitted to the second shaft 23 via the fifth gear 235 on the second shaft 23, Speed gear 301 of the two-speed shifting portion 30 and is output through the fourth shaft 35 directly from the high-speed gear 301 to the high / low clutch 32. [

5, the clutch retainer 260 of the third clutch 26 rotates by the rotation of the clutch retainer 220 of the first clutch 22, but idle because the clutch is in the neutral state The sixth gear 251 and the seventh gear 253 on the third shaft 25 are also engaged with the fourth gear 233 and the fifth gear 253 regardless of the rotation of the clutch retainer 260 of the third clutch 26, RTI ID = 0.0 > 235 < / RTI >

6 is implemented by the bidirectional simultaneous connection of the first clutch 22, in which case the engine power is transmitted via the first clutch 22 to the second gear (not shown) And is transmitted to the second shaft 23 through the fourth gear 233 meshing with the second gear 213 and is transmitted to the second gear 233 via the fifth gear 235, (301), and is output through the fourth shaft (35) directly from the high-speed gear (301) to the high / low clutch (32).

All of the clutches (the second and third clutches 26) except for the first clutch 22 among the clutches constituting the first speed change section 20 in the forward direction fourth high-speed shifting state are all in the neutral position The rotation of the first clutch 22 rotates the clutch retainer 240 of the second clutch 24 and the clutch retainer 260 of the third clutch 26 but the power is transmitted to the clutch hub of the clutch It does not.

The high / low clutch 32 of the second speed change portion 30 is connected to the low speed gear 303 side (not shown in the figure) The first speed change section 20 is shifted from the first forward speed change stage to the fourth forward speed change stage in the above-described forward speed first shift stage to the fourth shift stage shift stage, The operation of the first speed change portion is the same as that of the first speed change portion, so a detailed description thereof will be omitted.

7 to 10, a connection state of the clutches in the forward direction high-speed shifting and a corresponding power flow will be described.

Figs. 7 to 10 are views showing the connection state and power flow of the clutches in the forward direction high-speed shifting.

7 to 10, the reverse direction high-speed shifting is a state in which the high / low clutch 32 of the second transmission portion 30 is connected to the high-speed gear 301 side, The first clutch 22 constituting the second clutch 20 is connected to the first gear 211 side and the alternate connection of the third clutch 26 (Figs. 7 and 8) and the second clutch 24) is connected to the third gear 231 side and is implemented by the alternate connection of the third clutch 26 (Figs. 9 and 10) in this state.

7 is implemented by connecting the first clutch 22 to the first gear 211 side and the third clutch 26 to the seventh gear 253 side, and in this case, The engine power is transmitted to the second speed change portion (second speed change portion) via the first clutch 22, the third clutch 26, the third shaft 25, the seventh gear 253 and the fifth gear 235, 30 and is output through the fourth shaft 35 directly from the high-speed gear 301 to the high-low clutch 32. The high-

7, the second clutch 24 of the clutches constituting the first speed change section 20 is in the neutral position and therefore the second clutch 24 The power is not transmitted to the clutch hub of the clutch but the third gear 231 engaged with the first gear 211 also rotates but the second clutch 24 is not neutralized The rotation of the second shaft 23 is not affected.

8 is realized by connecting the first clutch 22 to the first gear 211 side and the third clutch 26 to the sixth gear 251 side, and in this case, The engine power is transmitted through the first clutch 22, the third clutch 26, the sixth gear 251, the fourth gear 233 and the fifth gear 235 to the second speed change portion 30 and is output through the fourth shaft 35 directly from the high-speed gear 301 to the high-low clutch 32. The high-

8, the second clutch 24 is also in the neutral position, so that the rotation of the first clutch 22 causes the clutch retainer 240 of the second clutch 24 to rotate However, no power is transmitted to the clutch hub of the clutch, and the third gear 231 engaged with the first gear 211 also rotates. However, since the second clutch 24 is in the neutral state, It does not affect rotation.

9 is implemented by connecting the second clutch 24 to the third gear 231 side and the third clutch 26 to the seventh gear 253 side, In this case, as shown by arrows in the figure, the engine power is transmitted to the first gear 211, the third gear 231, the second clutch 24, the third clutch 26, the seventh gear 253, 235 are sequentially transmitted to the high-speed stage gear 301 of the second speed change section 30 and output via the fourth shaft 35 directly via the high / low clutch 32.

9, the first clutch 22 of the clutches constituting the first transmission portion 20 is in the neutral position, and therefore the first clutch 22 is engaged by the second clutch 24, Although the clutch retainer 220 of the first gear 233 rotates, power is not transmitted to the clutch hub of the clutch and the second gear 213 rotates due to engagement with the fourth gear 233 on the second shaft 23, The rotation of the first shaft 21 is not affected because the clutch 22 is in the neutral state.

10 is realized by connecting the second clutch 24 to the third gear 231 side and connecting the third clutch 26 to the sixth gear 251 side, In this case, as shown by arrows in the figure, the engine power is transmitted to the first gear 211, the third gear 231, the second clutch 24, the third clutch 26, the sixth gear 251, 233 and the fifth gear 235 are sequentially transmitted to the high speed stage gear 301 of the second speed change section 30 and the high speed gear 32 is directly transmitted via the fourth shaft 35 do.

10, the first clutch 22 is in the neutral position, so that the clutch retainer 220 of the first clutch 22 is rotated by the second clutch 24 The power is not transmitted to the clutch hub of the clutch and the second gear 213 rotates due to the engagement with the fourth gear 233 on the second shaft 23 but since the first clutch 22 is in the neutral state, And does not affect the rotation of the shaft 21.

In the meantime, although not specifically shown in the drawings, the downward shift in the reverse direction is implemented in four stages in total, and the high / low clutch 32 of the second speed change portion 30 is connected to the low speed gear 303 side And the power input to the high speed gear 301 is decelerated while bypassing the intermediate shaft 33. In this case also, the operation of the first speed change portion 20 is the same as the above- The operation of the first speed change portion is the same as the operation of the first speed change portion in the high-speed transmission, so that a duplicate description will be omitted.

As described above, according to the transmission according to the embodiment of the present invention, a plurality of hydraulic clutches operated by hydraulic pressure are applied. As compared with the conventional mechanical configuration in which shifters are shifted to change the number of shifting gears, It is possible to alleviate and ease the operation, and it is possible to provide convenience of operation with high degree of satisfaction.

Further, mobility and stability can be ensured by reducing the impact of the shift shock, and a plurality of hydraulic clutches are arranged in parallel to realize a transmission, thereby achieving a multi-step transmission gear ratio without increasing the length of the transmission in the front- And has the effect of enabling traveling or operation at a more optimized speed that meets the conditions during traveling or work.

In the foregoing detailed description of the present invention, only specific embodiments thereof have been described. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

20: first transmission portion 21: first shaft
22: first clutch 23: second shaft
24: second clutch 25: third axis
26: third clutch 30: second speed changing portion
32; High / low clutch 33: intermediate shaft
35: fourth shaft 40: auxiliary transmission portion
211, 213, 231, 233, 235, 251, 253: first to seventh gears
301: High-speed gear 331: First intermediate gear
333: second intermediate gear 303: low speed gear

Claims (9)

A first shifting portion for forward-reverse shifting and a plurality of first-speed shifting portions; And
And a second shift portion disposed rearward of the first shift portion and performing a second shift for decelerating or decelerating the first shifted power in which the rotational direction is determined by the first shift portion,
Wherein the first transmission portion is constituted by a combination of a plurality of hydraulic clutches and transmission gears arranged in parallel,
And the second shift portion includes a hydraulic clutch disposed on the same axis as the first axis of the first shift portion connected to the engine output shaft.
The method according to claim 1,
The number of primary shift stages by the first transmission portion is four stages,
And the second speed change stage by the second speed change section is two stages.
The method according to claim 1,
Wherein the hydraulic clutch constituting the first transmission portion comprises:
A first clutch on the first shaft connected to an engine output shaft;
A second clutch disposed on a second shaft parallel to the first shaft and operatively connected to the first clutch;
And a third clutch that is disposed on a third axis parallel to the first axis and is independent of the second clutch and linked to the first clutch so as to be interlocked with the first clutch,
The power transmission gear
First and second gears provided on the first shaft;
Third and fourth gears on a second axis meshing with the first and second gears;
A fifth gear provided at the second axial end portion;
And sixth and seventh gears on the third axis that rotate in engagement with the fourth and fifth gears.
The method of claim 3,
And the clutch retainers of the first, second, and third clutches are rotatable about the corresponding axes (first, second, and third axles).
The method of claim 3,
The first gear and the second gear are disposed in front of and behind the first clutch, respectively,
The third gear and the fourth gear are disposed in front of and behind the second clutch,
And the sixth gear and the seventh gear are disposed behind the third clutch.
6. The method of claim 5,
The first, fourth, fifth, and seventh gears are rotated integrally with the corresponding shafts (first, second, and third shafts)
And the second, third, and sixth gears are rotatable about the corresponding axes (first, second, and third axes).
The method according to claim 1,
The second speed change portion
A high-speed short-range gear whose rotational direction is determined by the first speed change portion and whose first-speed shifted power is input;
An intermediate shaft having an intermediate gear that is parallel to an axis of the high-speed gear and is always rotated by engaging with the high-speed gear;
A low-speed short-range gear which is always rotated by being meshed with an intermediate gear on the other intermediate shaft of the part engaged with the high-speed short-term gear;
And a fourth shaft disposed on the same axis as the first shaft so as to be rotatable integrally with the fourth shaft, the first shaft and the fourth shaft being capable of power transmission And a high / low clutch of a planetary hydraulic clutch structure.
The method according to claim 1,
Further comprising: a second speed change unit for shifting the power output from the first speed change unit to the second speed change unit;
9. The method of claim 8,
Wherein the auxiliary speed-change portion comprises a synchromesh type manual transmission structure.

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