JPS6230500Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a traveling transmission device for a work vehicle, which is configured so that a traveling speed change operation can be performed without operating a main clutch on and off each time the gear is changed. The conventional device described above has an input shaft that is linked to the engine side and an output shaft that is linked to the traveling device side.
A hydraulic friction clutch in which a plurality of transmission gear pairs are supported in parallel along the axial direction, and an idling gear supported in an idling state among the transmission gear pairs is provided in each transmission gear pair in a sequential and reverse manner. The speed change operation was performed by switching between an integrally interlocking state and an idling state through a manual on/off operation. However, as the number of gears increases, the number of hydraulic friction clutches increases, resulting in an increase in the size of the entire device. In view of the above points, the present invention has been devised to reduce the number of hydraulic friction clutches that allow gear shifting operations without engaging or disengaging the main clutch, thereby making it possible to configure the device compactly. It is an object of the present invention to improve the arrangement so that the device can be made more compact and advantageous in terms of hydraulic piping for the clutch. Next, embodiments of the present invention will be described in detail based on the drawings. To drive the traveling device 1 in a tractor as an example of a work vehicle, power from the engine E is transmitted to the traveling device 1 via the main clutch 2, the transmission 3, the forward/reverse switching mechanism 4, and the differential mechanism 5. It is configured. As shown in FIG. 1, the transmission 3 is configured by connecting an input shaft 6 connected to the engine E to an output shaft 8 via a first or second branch transmission system 7a, 7b.
It is configured to transmit power to the The first or second branch transmission system 7a, 7b
A pair of first and second or third and fourth synchronized mesh gear transmission mechanisms 10a, 10b, 10 are connected to the first or second transmission shafts 9a, 9b.
c and 10d are provided to enable four-speed shifting, and first or second hydraulic friction clutches 11a and 11b, each of which is an example of a fluid pressure type, are interposed. The first transmission shaft 9a is configured as a cylindrical shaft, a second transmission shaft 9b is fitted inside the first transmission shaft 9a, and a first transmission shaft 9b is fitted on the rear end side of the first transmission shaft 9a.
and second synchronized mesh gear transmission mechanism 10
a, 10b, and third and fourth synchromesh type gear transmission mechanisms 10c, 10d are provided on the rear end side of the second transmission shaft 9b protruding from the first transmission shaft 9a, and on the other hand, the first transmission shaft 9a on the front end side of the first
The clutch 11a is connected to the first transmission shaft 9b of the second transmission shaft 9b.
The second clutch 11b is provided near the first clutch 11a on the front end side protruding from the transmission shaft 9a. The first to fourth synchronized mesh gear transmission mechanisms 10a, 10b, 10c, 10d are
As shown in FIG. 2, the shift fork 13 relative to the synchronizer sleeve 12 is operated by supplying pressure oil through electromagnetic three-position switching valves V ₁ , V ₂ , V ₃ , and V ₄ . and on each side of the shift fork 13 in the sliding displacement direction,
Limit switch that detects the gear shift position
_L1 to _L8 are attached. the first and second hydraulic friction clutches 11a;
11b is a two-position switching valve V which is always biased toward the switching side, is electromagnetic for the clutches 11a and 11b, and is configured to provide resistance to drained oil during the switching operation by means of a throttle flow path R. ₅ , configured to supply pressure oil via _V6 . Each of the three-position switching valves V ₁ , V ₂ , V ₃ , V ₄ is provided with a pair of solenoids S ₁ , S ₂ , . . . for operating the same.
S ₇ and S ₈ are attached, and two-position switching valves V ₅ and V ₆ are installed.
one solenoid each to operate it
S ₉ and S ₁₀ are attached, and by switching the speed change contacts F ₁ to _{F 8} in conjunction with the operation of the speed change operation lever 14, the limit switch is activated based on a command from the operation circuit 15.
Both clutches 11 are activated at a predetermined timing in conjunction with the detection results of the gear shift operation status by _L1 to _L8 .
a, 11b is switched to a transmission state while causing the slip transmission state to appear in the other clutch, and after the switching, a predetermined gear type transmission mechanism 10a to 10d is returned to the neutral position, and the solenoids S ₁ to S ₁₀ is configured as shown in the table below.

【table】

[Table] In the figure, reference numeral 16 denotes a power output shaft, which is configured to output power in a two-stage variable speed manner by changing gears to gears 17a and 17b fitted to the input shaft 6. Next, the transmission mechanisms 10a, 10b, 10c,
10d and the switching operation timing of the clutches 11a and 11b will be explained using a shift from the first speed _F1 to the second speed _F2 as an example. That is, only the first clutch 11a is in the engaged state, and only the small diameter gear 18a in the first transmission mechanism 10a is in a state of rotation integrally with the first transmission shaft 9a, so that the first speed state _F1 is obtained. and,
As the state is switched to second speed _F2 ,
First, in the third transmission mechanism 10c, the solenoid
By the excitation of _S5 , the small diameter gear 18e in the third transmission mechanism 10c is switched to a state where it rotates integrally with the second transmission shaft 9a, and then the switched state is detected by the limit switch _L5 , and then, The first clutch 11a is disengaged by demagnetizing the solenoid _S9 , and the second clutch 11b is engaged by energizing the other solenoid _S10 . The other second clutch 11b then enters the transmission state while producing a slip state, and after the transmission state is switched, the solenoid _S1 is demagnetized and the first transmission mechanism 10a is switched to the neutral state. The present invention can be applied not only to the case of shifting in 8 stages as described above, but also to the case of shifting in 4 or more stages. Two-position switching valves V ₅ , V ₆ equipped with the throttle flow path R
Then, as the operating circuit 15 switches the alternatively selected hydraulic friction clutch to the transmission state, the hydraulic friction clutch which was in the transmission state is switched to the slip transmission state. collectively referred to as the mechanism that causes In summary, the characteristic configuration of the traveling transmission for a work vehicle according to the present invention is that the input shaft is linked to the engine;
A plurality of branch transmission systems are interposed between the output shaft to the traveling device, and the transmission shafts of each of the branch transmission systems are fitted externally so that one transmission shaft can rotate with respect to the other transmission shaft. The double shaft is configured to have a double shaft, and the double shaft is shifted to one end side, and one of the input shaft and the output shaft and each of the transmission shaft are connected through a multi-stage synchronized mesh gear transmission mechanism. one hydraulic friction clutch is interposed on each of the transmission shafts, and the synchromesh type gear is interlocked with the gears by interlocking the double shafts, and one hydraulic friction clutch is interposed on each of the transmission shafts, and the synchromesh type gear At a position opposite to the transmission mechanism, the other of the input shaft and the output shaft and each of the transmission shafts are gear-coupled, and a hydraulic friction clutch in the plurality of branch transmission systems is selectively transmitted. the input shaft and the output shaft can be interlocked and connected via the alternatively selected branch transmission system, and the alternatively selected fluid is applied to the hydraulic friction clutch. A mechanism is provided for switching the hydraulic friction clutch which is in the transmission state to the transmission state while causing the slip transmission state to appear.
This configuration provides the following effects. That is, the input shaft and the output shaft are interlocked and connected by selectively selecting a branch transmission system each equipped with a multi-stage synchronized mesh gear transmission mechanism based on the operation of a hydraulic friction clutch. Therefore, compared to the case where a hydraulic friction clutch is provided for each transmission gear pair, the number of friction clutches can be reduced, and a transmission capable of shifting in multiple stages can be constructed compactly. Then, as the alternatively selected hydraulic friction clutch is switched to the transmission state, a switching mechanism is provided that switches and operates the fluid pressure friction clutch that is in the transmission state while bringing out the slip transmission state. Therefore, it is possible to avoid any of the branch transmission systems from being in a non-transmission state during the speed change operation, and to perform the speed change operation smoothly. Moreover, since the transmission shafts in the branch transmission system are rotatably fitted to each other to form a double shaft, the installation space in the direction orthogonal to the axis of the transmission shaft can be reduced, making the device even more compact. It can be configured as follows. Furthermore, since the hydraulic friction clutches of each branch transmission system are offset to one end of the double shaft and installed close to each other, the fluid pressure piping to these clutches can be consolidated compactly, and the control valve can be It is now possible to concentrate in one place and shorten the length of piping from that point as much as possible, which is advantageous in terms of piping. Note that although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the attached drawings by such entry.

[Brief explanation of the drawing]

The drawings show an embodiment of the traveling transmission system for a working vehicle according to the present invention, and FIG. 1 is a schematic plan view of the entire traveling transmission system, FIG. 2 is a cross-sectional view of the synchronized mesh gear transmission mechanism, and FIG. 3 is a block diagram. 1... Travel device, 6... Input shaft, 7a, 7b...
...Branch transmission system, 8...Output shaft, 9a, 9b...Transmission shaft, 10a, 10b, 10c, 10d...Synchronized mesh gear transmission mechanism, 11a, 11b...
...hydraulic friction clutch, E...engine.

Claims (1)

[Scope of utility model registration request] A plurality of branch transmission systems 7a, 7 are provided between the input shaft 6 linked to the engine E and the output shaft 8 to the traveling device 1.
b is interposed, and the transmission shafts 9a and 9b in each of the branch transmission systems 7a and 7b are configured as double shafts in which one transmission shaft 9a is rotatably fitted onto the other transmission shaft 9b, One end of the double shaft,
One of the input shaft 6 and the output shaft 8 and each of the transmission shafts 9a and 9b are connected to a multi-stage synchronized mesh gear transmission mechanism 10a, 10b, 10c, 1.
One hydraulic friction clutch 11a, 11b is interposed on each of the transmission shafts 9a, 9b, interlocked with a gear via the transmission shaft 9a, 9b, and shifted to the other end side of the double shaft. 11a and 11b, the synchronized gear transmission mechanism 10
a, 10b, 10c, and 10d, the other of the input shaft 6 and output shaft 8 and each of the transmission shafts 9a and 9b are gear-interlocked, and the plurality of branch transmission systems 7a , 7b are alternatively switched to the transmission state, and the alternatively selected branch transmission system (7a
or 7b) the input shaft 6 and the output shaft 8 via
The fluid pressure friction clutches 11a and 11b are connected to a fluid pressure friction clutch (11a or 11b) which is alternatively selected.
b) to the transmission state, the hydraulic friction clutch (11a or 1
1b) A traveling transmission device for a working vehicle, which is provided with a mechanism for switching and operating the transmission while creating a slip transmission state.