JPH0790793B2 - Work vehicle drive transmission - Google Patents

Description

The present invention relates to a traveling power transmission device for a working vehicle such as a combine.

[Conventional technology]

Some combine trucks, which are one of the work vehicles, are provided with a pair of left and right crawler type traveling devices as a traveling device, and are configured so that one traveling device is braked to make a turning turn. The structure is as follows.

That is, as shown in FIG. 9, when the left and right side gears (21L) and (21R) that transmit power to the left and right traveling devices (not shown) are both engaged with the transmission side gear (19), both traveling devices are powered. Are input gears (23R), (23L) and axles (22R), (22
It will flow in the forward direction via L) and the aircraft will go straight.
Then, for example, by sliding the left side gear (21L) to engage with the left braking side gear (26L), and operating the side brake (28) of the left braking side gear (26L),
The structure is such that the left traveling device is braked and the aircraft turns to the left.

Also, for the left side gear (21L), this is the transmission side gear (19).
Since the spring (50) that urges to the occlusal side is provided, when the sliding operation to the left braking side gear (26L) is stopped, the left side gear (21L) is moved to the left braking side by the urging force of the spring (50). It separates from the gear (26L) and engages with the transmission gear (19).

Further, after sliding the left and right side gears (21L) and (21R) into engagement with the left and right braking side gears (26L) and (26R), the left and right braking side gears (26L) are rotated by the main brake (42).
By braking the L) and (26R), the aircraft can be parked.

[Problems to be Solved by the Invention]

In the above-mentioned work vehicle, if the parking operation as described above is carried out immediately after the end of the turning turn by braking one traveling device, the following problems may occur.

That is, as shown in FIG. 9, for example, the left side gear (21
L) is engaged with the left braking gear (26L), and when performing parking operation immediately after turning to the right, the left side gear (21L) remains engaged with the left braking gear (26L) and the right side gear (2L
1R) is engaged with the right braking gear (26R) and the main brake (4R
2) Enter and operate.

In this case, the right braking side gear (26R) is connected to the left braking side gear (26R) via the gear (29), the transmission shaft (27) and the transmission system of the gear (29).
L), and this left braking side gear (26L) is also connected to the ground through the left side gear (21L), input gear (23L), axle (22L) and left traveling device, so right braking The side gear (26R) is not in a freely rotatable state, but is in a fixed state at a certain rotation phase. On the contrary, since the right side gear (21R) is also connected to the ground through the input gear (23R), the axle (22R) and the right traveling device, it is not in a freely rotatable state and is fixed at a certain rotation phase. It is in a state.

Therefore, when sliding the right side gear (21R) to engage with the right braking side gear (26R) in the above condition, the rotation phases of the right side gear (21R) and right braking side gear (26R) must match well. For example, the right side gear (21R) does not mesh smoothly with the right braking side gear (26R), and the right side gear (21R)
R) is forced to occlude. As a result, the surface pressure at the contact surfaces of the left and right side gears (21L), (21R) and the left and right braking side gears (26L), (26R) becomes extremely high.

Then, when the main brake (42) is turned on and operated again in the above-described state and the main brake (42) is turned off again to restart the vehicle, the left and right side gears (21L), (21L), (21L) are driven by the biasing force of the spring (50).
Even when trying to return R) to the occlusal side of the transmission side gear (19), the spring (50) can overcome the frictional force at this contact surface due to the high surface pressure at the contact surface. The left and right side gears (21L) and (21R) cannot be separated from the left and right braking side gears (26L) and (26R). Therefore, even if an attempt is made to move forward in this state, the transmission-side gear (19) simply idles and the vehicle cannot move forward.

Here, the present invention has an object to prevent a state in which the vehicle cannot move forward when the vehicle restarts as described above.

[Means for Solving the Problems]

A feature of the present invention is that the work vehicle as described above is configured as follows. In other words, each of the pair of side gears that transmits power to the pair of left and right traveling devices is slidably supported between the meshing position with the transmission gear and the meshing position with the pair of left and right braking gears including the side brakes. A main brake that applies braking to a transmission system that interlocks the two braking-side gears, and urges the side gears to slide from the meshing position with the braking-side gear to the meshing position with the transmission-side gear. The first spring and the second spring that urges the side gear to slide only from the meshing position with the braking side gear to the neutral position are provided, and the action and effect thereof are as follows. .

[Work]

With the configuration described above, the first spring and the second spring try to separate the side gear from the braking side gear when the side gear is in mesh with the braking side gear. Therefore, even if the contact pressure between the gear teeth of the side gear and the braking side gear is high and the side gear is in a state where it is difficult to separate from the braking side gear, a strong combined force of both the first spring and the second spring is exerted. The force causes the side gear to disengage from the braking gear, and the first
The side gear is engaged with the transmission side gear by the biasing force of the gear.

On the contrary, when the side gear is engaged with the transmission side gear and slidingly operated to the braking side gear, when the side gear is operated away from the transmission side gear, only the first spring acts as a resistance. Thereafter, when the side gear is slid from the neutral position (the position where neither the transmission side gear nor the braking side gear is engaged) to the engagement position with the braking side gear, the first spring and the second spring act as resistance.

〔The invention's effect〕

As described above, even when the parking brake is turned on and the side gear is hard to separate from the braking side gear immediately after turning the ground, the side gear is separated from the braking side gear by the biasing force of the first and second springs and transmitted. It was possible to engage the side gears, and the number of situations in which the vehicle could not move forward when restarting was reduced, and the running performance of the work vehicle could be improved.

In addition, a powerful spring that slides the side gear from the engagement position with the braking side gear to the engagement position with the transmission side gear is used.
A structure in which only a pair is provided is also conceivable, but in this structure, when the side gear is operated from the occlusal position with the transmission side gear to the neutral position, a large resistance acts from the spring, and the operation becomes very heavy.

However, when two types of springs having different urging forces are provided as in the present invention, the first spring of the present invention (from the position where the side gear is engaged with the braking side gear to the position where the side gear is engaged with the transmission side gear). The spring for urging the slide) does not need to be particularly strong, and the sliding operation from the engagement position of the side gear with the transmission side gear to the neutral position can be performed relatively easily.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 9 shows the structure inside the transmission case (8) of the traveling system of the combine, which is one of the work vehicles, and the power from the engine (not shown) is provided with a belt transmission mechanism (not shown) equipped with a tension clutch. ) Is transmitted to the input pulley (2) of the hydrostatic stepless transmission (1) and the power from the output shaft (3) of the hydrostatic stepless transmission (1) is transmitted to the first transmission shaft. It is transmitted from (4) through the one-way clutch (5) and the output pulley (7) to the mowing section (6) shown in FIG.

The power from the first transmission shaft (4) is transmitted to the second transmission shaft (11) via the first gear (9) and the second gear (10). A first high speed gear (12) is fitted to the second transmission shaft (11) so as to be relatively rotatable, and a shift gear (14) is slidably fitted to have a spline structure.

On the other hand, the second high speed gear (16) is attached to the third transmission shaft (15).
And the low speed gear (17) is fixed, the first high speed gear (12) meshes with the second high speed gear (16), and the third transmission shaft (1
A medium speed gear (18) is fixed to 5).

With the above structure, the shift gear (14) is slid to operate the first high speed gear (12), the medium speed gear (18), and the low speed gear (17).
The power can be shifted to three stages of high, medium and low by engaging with the gear. This power is transmitted to the transmission side gear (19) which meshes with the medium speed gear (18).

The right side gear (21R) and the left side gear (21L) are relatively rotatably fitted onto the support shaft (20) that supports the transmission side gear (19), and the left and right axles (22L) and (22R) are Input gears (23R), (23L) are left and right side gears (21L),
(21R) is constantly biting. This allows
Sliding the right or left side gears (21R), (21L) to engage / separate the transmission side gear (19), and transmit power to the drive sprocket (24a) of the crawler traveling device (24) shown in FIG. The side clutches (25R) and (25L) are formed between the transmission side gear (19) and the left and right side gears (21L) and (21R).

Next, the structure for braking one axle (22R) or (22L) will be described in detail. As shown in the figure, the support axle (20)
The right braking side gear (26R) and the left braking side gear (26L) are rotatably supported by the bearing, and the pair of third gears (29) fixed to the fourth transmission shaft (27) is right braking. It meshes with the side gear (26R) and the left braking side gear (26L).
A multi-plate hydraulically operated side brake (28) is provided at one end of the fourth transmission shaft (27) to separate the right side gear (21R) or the left side gear (21L) from the transmission side gear (19). Right braking side gear (26R) or left braking side gear (26R
One axle (22R) or (22L) by engaging the side brake (28) and operating it while engaging with (L)
Can be braked. As a result, a turning turn can be performed.

Next, the structure for reversing one of the axles (22R) or (22L) will be described in detail. As shown in the same figure, a fourth gear that meshes with the second high speed gear (16) of the third transmission shaft (15) ( 62)
Is externally fitted to the fourth transmission shaft (27) so as to be relatively rotatable, and a hydraulic clutch (30) is provided between the fourth gear (62) and the fourth transmission shaft (27). As a result, when the right side gear (21R) or the left side gear (21L) is engaged with the right braking side gear (26R) or the left braking side gear (26L) as described above, when the hydraulic clutch (30) is engaged and operated. Second
The power from the high speed gear (16) is transmitted in reverse to the axle (22R) or (22L) after being decelerated to 1/2. As a result, a super turning turn can be performed.

As shown in FIG. 1 and FIG. 9, in the left and right side gears (21L) and (21R), the left and right braking side gears (26L
A first spring (50) is provided to urge the left and right side gears (21L) and (21R) to slide from the position of engagement with L) and (26R) to the position of engagement with the transmission side gear (19). ing. Furthermore, from the position of engagement with the left and right braking gears (26L), (26R) to the neutral position (left and right side gears (21L), (21R)
The left and right braking gears (26L) and (26R) are also connected to the transmission gear (1
9) to the left and right side gears (2
A second spring (51) for urging the 1L) and (21R) to slide is provided.

Next, the hydraulic oil supply structure for the hydraulic cylinders (31R), (31L), which slides the left and right side gears (21L), (21R), the side brake (28), and the hydraulic clutch (30) will be described in detail. As shown in FIG. 8, the hydraulic oil from the pump (32) passes through the first switching valve (33) to the left and right side gears (21
L) and (21R) are supplied to the hydraulic cylinders (31R) and (31L), and an oil passage (34) from the side surfaces of the hydraulic cylinders (31R) and (31L) is connected to the side brake (28) and the hydraulic clutch ( The variable pressure relief valve (36) for the side brake (28) and the hydraulic clutch (30) is connected to the second switching valve (35) for the hydraulic brake (30). The relief valve (61) keeps the pressure of the entire hydraulic circuit at a safe allowable pressure.

Next, the operation of the first switching valve (33), the second switching valve (35) and the variable relief valve (36) will be described in detail. As shown in FIG. 8, the operation lever (39) which can be operated front and rear, right and left, the first switching valve (33), the second switching valve (35) and the variable relief valve (36).
Are mechanically linked to each other. For example, when the operation lever (39) is operated from the neutral position (N) to the first right turning position (R ₁ ) or the first left turning position (L ₁ ), the first switching valve ( The right or left side gear that was engaged with the transmission side gear (19) through the right or left operation part (46R) or (46L) by operating only 33) with the hydraulic cylinder (31R) or (31L). (21R), (2
1L) is operated away from the transmission side gear (19) and engages with the right or left braking side gears (26R), (26L).

In this case, the second spring (5
Since 1) and the right or left side gears (21R), (21L) are separated, slide the right or left side gears (21R), (21L) from the position of engagement with the transmission side gear (19) to the neutral position. Until then, only the resistance from the first spring (50) acts on the right or left side gear (21R), (21L). Then, as shown in FIG. 4, while sliding the right or left side gear (21R), (21L) from the neutral position to the engagement position with the right or left braking side gears (26R), (26L), 1 spring (50)
And the resistance from the second spring (51) causes the right or left side gear (21
R) and (21L).

In this state, the variable relief valve (36) is in the fully open state, and both the side brake (28) and the hydraulic clutch (30) are in the disengaged state, so that the right or left axle (22
R), (22L) is disengaged (side clutch (25R) or (25L) disengaged), and the aircraft slowly turns to the right or left. Further, the sequence valve (47) provided in the oil passage (34) is a right or left side gear (21R),
The pressure required to completely engage (21L) with the right or left braking gear (26R), (26L) is applied to the hydraulic cylinder (31R),
It is for securing (31L).

Next, the operation part (46L) for the left and right side gears (21L), (21R)
R) and (46L) will be described in detail. As shown in Figs. 1,6,7, a pair of support shafts (38
R) and (38L) are rotatably supported, and the bifurcated arms (40R) and (40L) fixed to the inner ends are engaged with the right and left side gears (21R) and (21L), respectively. is doing. The L-shaped operation arms (41R) and (41L) are fixed to the outer ends of the support shafts (38R) and (38L), and the lower ends of the operation arms (41R) and (41L) are hydraulically operated. Cylinder (31
R), (31L) are pushed down so that the right or left side gear (21R), (21L) becomes the right or left braking side gear (26R),
It is configured to be slid to the (26L) side.

Next, move the operating lever (39) to the right or left first turning position (R ₁ ),
When operating from (L ₁ ) to the right or left second turning position (R ₂ ), (L ₂ ), the right or left side gear (21R), (21L) moves to the right or left braking side gear (26R), (26L) and the second switching valve (35) is operated to supply hydraulic fluid to the side brake (28), the variable relief valve (36) is gradually closed from the fully open state. It will be operated. As a result, the side brake (28) starts to operate and the right or left axle (22
R) and (22L) are gradually braked, and the aircraft makes a right turn or left turn. Then, the braking force of the side brake (28) is maximized at the right or left second turning position (R ₂ ) or (L ₂ ) of the operating lever (39).

Next, the third pivot position right or left operating lever (39) (R _3), in the state as described above and operated to (L _3), the second
The switching valve (35) is switched to the hydraulic oil supply side to the hydraulic clutch (30). As a result, the side brake (28) is disengaged, the hydraulic clutch (30) is engaged, and the right or left axles (22R), (22L) are reversely driven, and the aircraft is superposed to the right or left. Turn around and go.

Further, the third switching valve (37) for the hydraulic cylinder (60) for raising and lowering the mowing section (6) and the operating lever (39) are mechanically linked. Thus, the reaper (6) can be moved up and down by operating the operation lever (39) to the ascending position or the descending position (upward or backward of the paper surface).

Next, the operation structure of the main brake (42) will be described in detail.
As shown in FIG. 9, a main brake (42) is provided at the other end of the fourth transmission shaft (27), and as shown in FIG. 1, the main brake (42) and the brake pedal (43). Are linked via a link (44). Then, in the operation portions (46R) and (46L) for the left and right side gears (21L) and (21R), one end of the outer wire (45a) of the release wire (45) is attached to the upper ends of the left and right operation arms (41L). While being connected, a bracket (48) is attached to one end of the inner wire (45b) of this release wire (45),
The pin (41Ra) of the right operation arm (41R) is engaged with the elongated hole (48a) of the bracket (48). And
The other end of the inner wire (45b) of the release wire (45) is connected to the brake pedal (43).

Next, a case where the brake pedal (43) is depressed at the end of turning will be described in detail. For example, as shown in FIG.
The left side gear (21L) is engaged with the left braking side gear (26L) and the right side gear (21R) is engaged with the transmission side gear (19). It is assumed that the hydraulic continuously variable transmission (1) is temporarily stopped by performing a stop operation. In this case, return the operating lever (39) to the neutral position (N) in order to ensure safety during stop and restart.
Operate the brake pedal (43) to operate the brake pedal (4
Fix 3) with the hook member (52).

When the operating lever (39) is returned to the neutral position (N) in this way, the supply of hydraulic oil to the side brake (28) and the hydraulic clutch (30) is cut off and both are in the disengaged state. 31R) and (31L) contract upward. When the brake pedal (43) is stepped on, the inner wire (45b) is pulled so that the transmission side gear (19)
The right side gear (21R) that has been engaged with is slidingly operated until it engages with the right braking side gear (26R) as shown in FIG. 5, and the main brake (42) is turned on.

After that, when the brake pedal (43) is released to restart the vehicle, the first spring (50) is returned as shown in FIGS. 5 to 1.
And the urging force of the second spring (51) causes the left and right side gears (21
L) and (21R) are operated separately from the left and right braking gears (26L) and (26R). Then, in the neutral position, the second spring (5
1) separates from the left and right side gears (21L) and (21R), and the urging force of the first spring (50) causes the left and right side gears (21L) to move.
L) and (21R) are slid to the position where they engage with the transmission side gear (19).

[Another embodiment]

As shown in FIG. 11, instead of the coil spring-shaped second spring (51), a disc spring-shaped second spring (52) may be provided.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of the traveling power transmission device for a work vehicle according to the present invention. FIG. 1 is a front view of the left and right side gears and the vicinity of the operating portion in a straight traveling state in which the left and right side gears mesh with the transmission side gears, and FIG. 1 is a front view showing a state in which the left side gear is operated to a neutral position from the state shown in FIG. 1, FIG. 3 is an enlarged view of the vicinity of the left side gear in FIG. 2, and FIG. 4 is a state in which the left side gear is moved to the left from the state shown in FIG. FIG. 5 is a front view showing a state in which the control side gear is engaged, FIG. 5 is a front view showing a state in which the left and right side gears are engaged with the left and right braking side gears by stepping on the brake pedal, and FIG. 6 is an operation for the left and right side gears. Perspective view of part 7,
Fig. 8 is a front view of the operating unit and hydraulic cylinder, Fig. 8 is a hydraulic circuit diagram of each control valve, Fig. 9 is a vertical sectional front view of the mission case, Fig. 10 is a side view of the combine front, and Fig. 11 is another. It is an enlarged view of the left side gear vicinity showing an example. (19) …… Transmission side gear, (21R), (21L) …… Side gear, (24) …… Traveling device, (26R), (26L) …… Control side gear, (28) …… Side brake, ( 42) …… Main brake, (50) …… First spring, (51), (52) …… Second spring.

Claims (1)

[Claims] 1. A pair of side gears (21R), (21L) for transmitting power to a pair of left and right traveling devices (24), (24) are respectively provided at an engagement position with a transmission side gear (19) and a side brake (21). 28) a pair of left and right braking gears (26R), (26L)
The side gear (21R) is provided with a main brake (42) which is slidably supported in an occlusal position with and which applies a brake to a transmission system that interlocks and connects the both braking side gears (26R) and (26L). , (21L) to the braking gear (26R), (26
A first spring (50) for urging the slide gear (19) to slide to a transmission gear (19).
Replace the side gears (21R) and (21L) with the braking side gear (26
R), (26L), a traveling transmission device for a work vehicle, comprising: second springs (51), (52) for urging the second spring (51), (52) to slide only from the occlusal position to the neutral position.