JPH0244134Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a travel transmission device for a work vehicle such as a combine harvester.

[Problems to be solved by the prior art and the invention]

Generally, some work vehicles of this type are capable of stepless speed change by operating a speed change lever. However, in the traveling transmission system of such a work vehicle, when changing the main gear such as forward or backward, the main gear is switched with the clutch disengaged, but after switching the main gear, the clutch must be switched again. When you connect the
When the lever position of the continuously variable transmission mechanism is set to the high speed side, power is transmitted with a large shock (acceleration).
A sudden start of the aircraft is not acceptable, and is extremely uncomfortable for the operator. It also places an excessive load on the power transmission system, so the power transmission system must be designed to withstand this sudden start. It has become a problem because it has drawbacks such as having to make it large.

[Means to solve the problem]

In view of the above-mentioned circumstances, the present invention was devised for the purpose of providing a traveling transmission device for a work vehicle that can eliminate these shortcomings, and allows stepless traveling by lever operation. In a work vehicle that is equipped with a continuously variable transmission mechanism that changes speed and a main transmission mechanism that changes speeds such as forward and backward, the continuously variable transmission mechanism is configured to stop transmitting power when the lowest speed is reached. In addition to providing a clutch mechanism that can be disengaged, the main transmission mechanism and the continuously traveling transmission mechanism are connected to the gear shifting operation of the main transmission mechanism, and automatically shift to the lowest speed side regardless of the lever position. It is characterized by being interlocked and connected so as to be displaced and cut off power transmission.

With this configuration, the present invention allows for a gradual resumption of running without a shock even if the continuously variable transmission mechanism is in a high speed state when resuming driving after switching the main gear. This is how it was done.

[Example] Next, an example of the present invention will be described based on the drawings. In the drawing, reference numeral 1 denotes a traveling machine of a combine harvester, and the traveling machine 1 includes a pre-processing section 2 for reaping stem culms, a threshing section 3 for threshing the harvested stem culms, and a post-processing section for shredding the harvested culms, etc. It is composed of a post-processing section 4 for processing, a sorting section 5 for sorting and storing the threshed material, an operation control section 6, a crawler-type running section 7, etc., all of which are the same as before. be.

Reference numeral 8 denotes a continuously variable traveling transmission mechanism, which includes an input pulley 9 that is belt-transmitted to an engine (not shown), and split pulleys 10a and 10b on a fixed side and a movable side provided on the input pulley 9. The drive side speed change pulley 10 is made up of a drive side speed change pulley 10, the driven side speed change pulley 11 is also made of a split pulley, and a speed change belt 12 that is suspended around both these pulleys 10 and 11. The movable split pulley 10a of the pulley 10 is spline-fitted to the input shaft (counter shaft) 13 so as to be slidable in the axial direction while being biased in the axial direction by the elastic force 14. Here, 14a is a bullet receiver provided on the movable split pulley 10a side. An idle pulley 15 is provided on the outer ring of a bearing 15a on which the bullet receiver 14a is supported, and as will be described later, by operating the traveling speed change lever to the zero speed position, the movable split pulley 10a is switched to the fixed split pulley 10b. When the transmission belt 12 is positioned at the maximum distance from the transmission pulley 15, the transmission belt 12 is received by the idle pulley 15 and becomes free from the driving transmission pulley 10, thereby preventing power transmission from the transmission pulley 10 to the transmission belt 12. The clutch mechanism of the present invention is constituted by this.

Further, a cam mechanism, which will be described later, is provided to perform the traveling speed change operation of the continuously variable traveling transmission mechanism 8. That is, a first speed change cam 16 is rotatably provided on the movable split pulley 10a via a bearing 16a, while a second speed change cam 34 corresponding to the first speed change cam 16 is mounted on the outer surface of the counter case 18. It is integrated. By adjusting the relative rotation of the first speed change cam 16 around the axis with respect to the second speed change cam 34, the movable split pulley 10a is moved in the axial direction while being biased by the elastic machine 14. As a result, a stepless traveling speed change is achieved, and the rotation of the first speed change cam 16 is performed in the following manner. That is, the first speed change cam 16 is provided with an arm body 16b projecting from the arm body 16b, and a cylinder rod of a hydraulic cylinder 17 and one end of a connecting rod 19 to be described later are attached to a shaft 16c.
has been done. The hydraulic cylinder 17 receives and receives pressure oil from the hydraulic pump 21 by switching the hydraulic valve 20 provided on the counter case 18, which will be described later, and thereby expands and contracts. Particularly, the first speed change cam 16 is set to be rotated so that the movable split pulley 10a moves to the high speed side close to the fixed split pulley 10b, and in this way, the hydraulic operating mechanism is configured. ing.

On the other hand, reference numeral 22 is a stepless traveling speed change lever arranged at a position that can be operated by the operator from the operation control section 6. It can be operated steplessly from speed to zero,
A locking groove is formed in the operation guide 23a, so that the traveling speed change lever 22 can be locked and held at an arbitrary speed change position. Note that 22a is a return mechanism for the traveling speed change lever 22.

Further, the connecting rod 19 is interlocked with an operating shaft 26 that is rotatably supported on the aircraft body side, and a fork-shaped arm portion 27b is provided at the tip of the operating shaft 26. , 27c is integrally provided, and a bar-shaped detection body 28 is provided swingably between the arms 27b and 27c. Moreover, this detection body 28 is arranged so as to be located on the low speed side with respect to the travel gear shift lever 22, and is controlled by both regulating portions 27a provided at the base end portions of the arm portions 27b and 27c of the actuation bracket 27. It is designed to be able to swing within a regulated range. Furthermore, 29 is a detection body 28 and a switching arm 20a of the hydraulic valve 20.
One side of the outer receiver 29a of the inner wire 29 is connected to the counter case 18, and the other side is connected to the actuating bracket 2.
7 is provided on one arm portion 27b. The inner wire 29 is stretched between a first ammunition 30 and a second ammunition 31 so that they are urged in opposite directions from both ends thereof.
is interposed between the detection body 28 and the other arm 27c of the actuation bracket 27, and the second ammunition 3
1 is interposed between the switching arm 20a and the fuselage side. In addition, the biasing forces K ₁ and K ₂ of the first aircraft 30 are set to be larger (K ₁ >K ₂ ). As a result, the sensing body 28
is the traveling gear shift lever 2 located at an arbitrary speed position.
2 from the low-speed side, the detection body 28 is located at a neutral position between the arms 27b and 27c, and the biasing force of the second bullet 31 is applied to the biasing force _K1 of the first bullet 30. The hydraulic valve 20 is set to be in a neutral state in a balanced state in which the force K ₂ and the pressing force of the detection body 28 in contact with the traveling speed change lever 22 are balanced. When the traveling gear shift lever 22 is operated from a low speed side to a high speed side from a neutral state where there is no speed change, the sensing body 28 remains and the traveling gear shift lever 2
Since the biasing force K ₁ of the first bullet aircraft 30 overcomes the bias force K ₂ of the second bullet aircraft 31, the detection body 28 pulls on the first bullet aircraft 30. The regulating portion 27 on the other arm portion 27c side follows the operation of the traveling speed change lever 22 to the high speed side so as to
It is displaced to the side that comes into contact with a. Therefore, the inner wire 29 is pulled and the hydraulic valve 20 is switched, thereby the hydraulic cylinder 17 is extended, and the first speed change cam 16 is connected to the movable split pulley 10 as described above.
a rotates toward the high speed side closer to the fixed split pulley 10b. Due to the rotation of the first shift cam 16, the operating bracket 27 itself is also displaced and rotated following the traveling shift lever 22. Then, the detection body 28 detects the travel gear shift lever 2.
2, the biasing forces of both bombs 30 and 31 are in the balanced state described above, and when the sensing body 28 returns to the neutral position separated from the regulating portion 27a of the actuating bracket 27, the hydraulic valve 20 becomes neutral again. In this state, the extension of the hydraulic cylinder 17 is stopped and this speed state is maintained. Further, when the travel gear shift lever 22 is operated to the low speed side, the detection body 28 is brought into contact with the regulating body 27a on the one arm portion 27b side by the travel gear shift lever 22 in a state that resists the first bomber 30. As a result, the inner wire 29 is pulled in the opposite direction by the biasing force of the second bullet 31. Therefore, the hydraulic valve 20 is switched to the opposite side, whereby the hydraulic cylinder 17 is contracted until it reaches the above-mentioned balanced state, and in this way, continuously variable traveling to the low speed side is achieved. There is.

Further, 32 is a main shift lever, and the main shift lever 32 is set to neutral N, and two forward gears F ₁ , F ₂ ,
The main shift lever 32 is interlocked with the transmission 24 via a connecting wire 25 so as to be able to perform a main gear shift of one reverse gear R, but the main shift lever 32 is also interlocked with the detection body 28 via a connecting wire 33. connected. And the main gear shift lever 32
When the gear is removed from the shift guide groove 32a in order to change gears, the connecting wire 33 is pulled, and this causes the detection body 28 to be in the state where the first bullet 30 is extended, regardless of the shift position of the traveling shift lever 22. This causes the hydraulic valve 2 to shift from the neutral position to the deceleration side.
0 switches to the contraction side of the hydraulic cylinder 17 and becomes the lowest speed state, and the speed change belt 12 shifts to the idle pulley 1.
5, the power is cut off. Next, when the main shift lever 32 is locked in a desired shift guide groove 32a, the tensile action of the connecting wire 33 on the detection body 28 is released, and the detection body 28 attempts to come into contact with the traveling shift lever 22 as described above. A speed increasing operation is performed, and in this way, a short start can be performed when the main shift lever 32 is engaged.

In the embodiment of the present invention configured as described above, when the travel gear shift lever 22 is operated to shift to the high speed side as described above, the biasing force K ₁ of the first projectile 30 becomes greater than that of the second projectile 31. As a result, the detection body 28 is displaced to the side where it comes into contact with the regulating body 27a of the actuation bracket 27, and thereby the hydraulic valve 2
0 is switched, the hydraulic cylinder 17 is extended, and the first speed change cam 16 is rotated so that the movable split pulley 10a approaches the fixed split pulley 10b. It will change to the side. Then, the detection body 28 comes into contact with the traveling speed change lever 22, the balance between the two bombers 30 and 31 is achieved, and when the detection body 28 returns to the neutral position between the arms 27b and 27c of the operating bracket 27, the inner wire 29 Returned hydraulic valve 20
is switched to a neutral state, thereby maintaining the operated travel speed state.
In addition, when operating to the low speed side, the detection body 28
In this case, the first bomb 30 is extended and displaced to the opposite side, whereby the hydraulic valve 20 is switched to the opposite side, the hydraulic cylinder 17 is contracted, and the traveling speed is changed to the corresponding low speed traveling state. .

In this way, in the present invention, stepless traveling speed change can be performed by operating the travel speed change lever 22, but when the main speed change is performed using the main speed change lever 32, This means that even if the temporary running gear shift lever 22 is in the high speed state, the aircraft can run from a low speed. That is, when the main gear shift lever 32 is removed from the gear shift guide groove 32a in which it is locked in order to perform the main gear changeover operation, the detection body 28 is forcibly moved from the neutral position to the deceleration position side against the first projectile 30. is forced to move,
As a result, the hydraulic valve 20 is switched, the hydraulic cylinder 17 expands and contracts, and the continuously variable traveling transmission 8
automatically changes to a state of zero speed, which is the lowest speed, that is, a state where the power is cut off. If the main shift lever 32 is locked in a desired shift guide groove 32a in this state, the forcible deceleration side deformation action of the sensing body 28 is released, thereby causing the above-mentioned deceleration side to be deformed. As such, the sensing body 28 is displaced toward the speed increasing side under the urging force of the first bomb 30, until the sensing body 28 comes into contact with the travel gear shift lever 22 and a balanced state is achieved between the two bombs 30 and 31. , the speed will be increased. Therefore, even if the temporary traveling gear shift lever 22 is in the high speed position, it is possible to start from a low speed without a shock, which may make it possible to resume traveling safely, but it causes discomfort to the work vehicle. This also means that the load on the transmission mechanism can be greatly reduced. Moreover, in this shockless start, when the main gear shift lever 32 is turned off, the gear shift belt 12 is automatically put into a power-off state where it is suspended around the idle pulley 15, so the clutch can be disengaged by depressing the clutch pedal or the like. There is no need to do so, and the operability is significantly improved and the structure can be simplified.

[Function and effect]

In summary, since the present invention is constructed as described above, by changing the speed of the main transmission mechanism, the continuously variable transmission mechanism can be operated even if the lever position is in the high speed state. Regardless of the speed, the clutch mechanism automatically changes to the lowest speed side and the power is cut off by the clutch mechanism. Therefore, when the main gear changeover is performed and travel is resumed, the aircraft changes from the lowest speed state to the lever position. This means that the speed will be increased steplessly to the maximum speed, and therefore, a shockless start without a shock will be possible, ensuring safety and
This not only greatly improves workability but also reduces the load applied to the power transmission mechanism. Furthermore, since the power is automatically cut off by switching the main gear, there is no need for the conventionally required clutch disengagement operation, resulting in further improved workability.

[Brief explanation of the drawing]

The drawing shows one embodiment of the traveling transmission device for the working vehicle according to the present invention, and shows the first embodiment of the traveling transmission device for the work traveling vehicle according to the present invention.
FIG. 2 is a perspective view of the combine harvester, FIG. 2 is a schematic perspective view of the transmission mechanism, FIG. 3 is an exploded view of the main parts of the drive side portion of the traveling transmission, and FIG. 4 is an explanatory view of the operation. In the figure, 8 is a travel transmission, 22 is a travel shift lever, 28 is a detection body, and 32 is a main shift lever.

Claims (1)

[Scope of utility model registration request] In a work vehicle that is equipped with a continuously variable transmission mechanism that performs stepless traveling speed changes by operating a lever, and a main transmission mechanism that changes speeds such as forward and backward, the continuously variable transmission mechanism includes at least one In addition, the main transmission mechanism and the continuously variable transmission mechanism are equipped with a clutch mechanism that cuts off power transmission when the main transmission mechanism reaches the gear shift position. A travel transmission device for a work vehicle, characterized in that it is interlocked and connected so as to automatically shift to the lowest speed side regardless of position and cut off power transmission.