JPH0774013B2 - Work vehicle steering structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering structure for a work vehicle provided with a traveling device such as a crawler traveling device which cannot be operated alone for traveling.

[Conventional technology]

In a combine, which is one of the above-mentioned work vehicles, as disclosed in, for example, Japanese Patent Laid-Open No. 63-13866,
By sliding a pair of side gears that transmit power to the pair of left and right crawler traveling devices and separating them from the transmission side gear, the transmission to one crawler traveling device is cut off and a gentle turn is performed, and the side gears are further slid. Then, there is a configuration in which a crawler traveling device on one side is braked to make a pivotal turn by pressing and operating a multi-plate side brake with a side gear.

[Problems to be Solved by the Invention]

According to the disclosed structure, the side brakes for braking the crawler traveling device at the time of turning the ground are structured such that the left and right crawler traveling devices are respectively provided with two side brakes, one set each. Therefore, it has been a cause of complicating the structure, increasing the number of parts, and increasing the cost.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to simplify the steering structure of the work vehicle.

[Means for Solving the Problems]

The features of the present invention are, in the steering structure of a work vehicle as described above, separate side gears for transmitting power to respective left and right traveling devices, an engagement position with a transmission side gear, and a side gear separately for each side gear. A transmission shaft which is configured to be slidable over a corresponding engagement position with a pair of first braking side gears, and which is provided with a pair of second braking side gears that are respectively engaged with the first braking side gears in a fitted state. And acting on the transmission shaft,
A single friction side brake for braking the braking gear and a reverse rotation transmission mechanism for transmitting power from the drive source side to the first and second braking gears in the reverse rotation state are provided, and the reverse rotation transmission mechanism is provided. The reverse rotation transmission state and the non-transmission state can be switched.

In addition to the above configuration, the shift output from the hydrostatic continuously variable transmission is configured to be transmitted in parallel to the transmission side gear and the reverse rotation transmission mechanism, and the operation and effect thereof are as follows. Is.

[Action]

With the configuration described in the preceding paragraph, for example, by separating the right side gear from the transmission side gear, the transmission to the right side traveling device is cut off, and a gentle turn is made to the right side. When the side brake is engaged with the braking side gear and the side brake is turned on, the traveling device on the right side is braked via this side gear, and the right turn can be performed. And, even when the left side gear is separated from the transmission side gear and is engaged with the first braking side gear,
When the side brake is turned on, the left traveling device is braked through the left side gear, so that the left side can make a turning turn. In other words, one pair of friction side brakes can turn left and right, and the braking force can be changed in multiple stages.

When one of the side gears is engaged with the first braking side gear and the reverse rotation transmission mechanism is operated to enter the reverse rotation transmission state, one of the traveling devices is reversely driven through the side gear, so-called super transmission. You can turn. In this case, even if the other side gear is engaged with the first braking side gear, the other traveling device can be similarly driven in the reverse direction, and the left and right traveling devices can be separately driven in the reverse direction by one set of the reverse rotation transmission mechanism. Of.

Further, since both the first braking side gears are individually meshed with the pair of second braking side gears, for example, the first braking side gear and the second braking side gear are
The intermediate shaft and the like can be omitted as compared with the case where the intermediate shaft provided with the reverse gear that meshes with those gears is provided between the braking gear and the braking gear.

According to the construction described in the preceding paragraph, the left and right gentle turning and the landing turning by the pair of side brakes as described above, and the left and right super landing turning by the pair of reverse rotation transmission mechanisms can be performed by stepless speed shifting. is there.

〔The invention's effect〕

As described above, the two brakes of the side brakes that are conventionally provided are not impaired without impairing the function of braking one traveling device to make a turning turn and the function of changing the braking force. One can be omitted, and the intermediate shaft for the reverse rotation transmission mechanism can be omitted, which simplifies the structure and reduces the number of parts.
Also, the manufacturing cost could be reduced. Then, by effectively utilizing the above-mentioned structure, one set of reverse transmission mechanism enables super-spinning turning by reversing one traveling device without causing a significant increase in manufacturing cost.

If a hydrostatic stepless transmission is added to the above configuration, the speeds of gentle turning, landing turning, and super landing turning can be steplessly changed to improve the turning performance of the work vehicle. be able to.

〔Example〕

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

FIG. 13 shows the structure in the transmission case (8) of the traveling system of the combine, which is one of the work vehicles, in which the power from the engine (not shown) has 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 reaper (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), and the second transmission shaft (11). The first high speed gear (1
The 2) and the first low speed gear (13) are fitted to each other so as to be rotatable relative to each other, and the shift gear (14) is fitted to be slidable with a spline structure.

On the other hand, the second high speed gear (16) and the second low speed gear (17) fixed to the third transmission shaft (15) are connected to the first high speed gear (1
2) and the first low speed gear (13) are in mesh with each other, and the middle speed gear (18) is fixed to the third transmission shaft (15).

With the above structure, the shift gear (14) is slid to engage with the first high speed gear (12), the medium speed gear (18) and the first low speed gear (13) to shift the power to three stages of high, medium and low. This is possible, and this power is transmitted to the third gear as the transmission side gear (19) that meshes with the medium speed gear (18).

A right side gear (21R) and a left side gear (21L) are fitted to the support shaft (20) supporting the third gear (19) so as to be relatively rotatable, and the left and right axles (22R) and (22L) are Input gears (23R), (23L) are left and right side gears (21L), (2
1R) is constantly biting. As a result, the right or left side gears (21R), (21L) are slidingly operated with respect to the third gear (19) so as to be occluded and separated, and the sprocket (24a) of the crawler traveling device (24) shown in FIG. 14 is powered. The transmission is turned on and off, and the side clutch (25) is placed between the third gear (19) and the left and right side gears (21L), (21R).
R) and (25L) are configured.

Next, the structure for braking one axle (22R) or (22L) will be described in detail. As shown in the figure, the support axle (20)
A right fourth gear and a left fourth gear as first braking gears (26R) and (26L) are rotatably supported by a bearing, and a pair of first gears fixed to the fourth transmission shaft (27) are 5th gear (29) (an example of the 2nd braking side gear) is the 4th right gear (26R)
And the left fourth gear (26L) is engaged. 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 third gear (19). By engaging the right fourth gear (26R) or the left fourth gear (26L) and operating the side brake (28), one axle (22R) or (22L) can be braked. .

Next, a detailed description will be given of the reverse rotation transmission mechanism (30) that reverses one axle (22R) or (22L), as shown in FIG.
The sixth gear (62) (an example of a reverse rotation gear) that meshes with the second high speed gear (16) of the third transmission shaft (15) is the fourth transmission shaft (2).
7) It is fitted to the outer surface of the 6th gear (6
A hydraulic clutch as a reverse rotation transmission mechanism (30) is provided between 2) 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 fourth gear (26R) or the left fourth gear (26L) as described above, the hydraulic clutch (30) is 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.

Next, the hydraulic oil supply structure for the hydraulic cylinders (31R), (31L) side brakes (28) and the hydraulic clutch (30) for sliding the left and right side gears (21L), (21R) will be described in detail. As shown in the figure, the hydraulic fluid from the pump (32) passes through the first switching valve (33) to the hydraulic cylinders (31R), (31R) for the left and right side gears (21L), (21R).
L) and hydraulic cylinders (31R), (31
The oil passage (34) from the side surface of L) is connected to the second switching valve (35) for the side brake (28) and the hydraulic clutch (30), and the oil passage (34) is connected to the variable relief valve (36). Has been done. The relief valve (61) keeps the pressure of the entire hydraulic circuit at a safe allowable pressure.

Next, the operation structure 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. 2, the left and right sides of the body control section (not shown) Front and rear axis (P ₂ ) of the frame (38) that is swingably supported around the axis (P ₁ )
An operation lever (39) is swingably supported around the operation lever (39) so that the operation lever (39) can be swung back and forth and left and right.

A first arm (40) is fixed to the operation lever (39), and the first arm (40) and the first switching valve (33) are linked with each other. As shown in FIGS. 2, 3, and 4, this structure has an operation plate (43) and an arm (41a) in front of and behind a support shaft (41) which is rotatable around a front and rear axis (P ₃ ) of a mission case (8).
Is fixed, one arm (41a) is connected to the spool (not shown) of the first control valve (33), and the other operation plate (43) is connected to the actuator (42).
The operation plate (43) is provided with an elongated hole (43a), and the pin (45a) of the push full wire (45) connected to the first arm (40) of the operation lever (39) is provided with the elongated hole (43a). 43a)
The pin (45a) and the operation plate (4
The spiral spring (44) is attached so that both of the pins (43b) of 3) are inserted.

With the above structure, the longitudinal axis of the operating lever (39) (P ₂ )
When the push full wire (45) is pushed and pulled by the swinging operation around, the operation plate (43) and the arm (41a) are swingingly operated through the spiral spring (44), and the first switching valve (33) is switched. Then, even after the spool of the first switching valve (33) reaches the stroke end, the operation lever (39) can be further swung by the accommodation of the spiral spring (44) and the elongated hole (43a). There is. As a result, one hydraulic cylinder (31R) or (31R
L) is supplied with hydraulic oil and piston (31RP) or (31LP)
Project downwards and the side gear arm (46R) or (46L) is rocked to move the right side gear (21R) or the left side gear (21L) away from the third gear (19), and the right fourth gear (26R).
R) or the left fourth gear (26L). This is the disengaged state of the left and right side clutches (25R) and (25L).

Also, as shown in FIG. 1, hydraulic cylinders (31R), (31L)
By the sequence valve (47) provided in the oil passage (34), the pressure required for the left and right side gears (21L) and (21R) to completely mesh with the left and right fourth gears (26L) and (26R) is provided. It is secured in the hydraulic cylinders (31R) and (31L). As shown in Fig. 5, this is the piston (31RP), (31L
When P) starts to protrude downward, cylinders (31RS), (31L
This is because the oil passage (34) connected to S) opens, and the position where this oil passage (34) started to open (left and right side gears (21L),
This prevents the piston (31RP) or (31LP) from stopping at the position where (21R) does not completely mesh with the left and right fourth gears (26L) and (26R).

The actuator (42) is for automatically switching the first switching valve (33) when the machine automatically travels along the planted grain rod, and is operated by the operation lever (39) as described above. It is in a state where it can move freely during human operation.

Also, as shown in FIG. 5, hydraulic cylinders (31R), (31L)
Oil passage (34) on the inner surface of cylinder (31RS), (31LS)
The inner diameter of the part (31a) is cut so that it becomes slightly larger, but this works as uniformly as possible from the radial direction of the cylinders (31RS), (31LS) when the hydraulic oil escapes to the oil passage (34). Piston (31RP), (31LP) to allow oil to escape
This is to prevent the twisting phenomenon caused by one-sided contact.

Next, the linkage structure of the operation lever (39) with the second switching valve (35) and the variable relief valve (36) will be described in detail.
Pin (49a) against operating lever (39) as shown
The second arm (49) provided with is fixed, and the first swing arm (50) and the second swing arm (51) are arranged around the front-rear axis (P ₂ ) and the operation lever (39). It is independently rockable and supported. The pin (38b) of the fixed arm (38a) extending downward from the frame (38) is
The spring (52) is inserted between the second swing arms (50) and (51), and the spring (52) is attached to the first and second swing arms (50) and (51).
The inner wire (53a) of the release wire (53) is attached to the first swing arm (50), and the outer wire (53b) is attached to the second swing arm (51).
Is attached to.

On the other hand, as shown in FIGS. 6, 7, and 8, the second switching valve (35) and the variable relief valve (36) are arranged in parallel, and
The first operation arm is provided inside the support shaft (54) rotatable about the axis (P ₄ ) orthogonal to the spools (35a) and (36a) of the second switching valve (35) and the variable relief valve (36). (48), support shaft (5
The second operation arm (55) is fixed to the outside of 4).
Then, the inner wire (53a) of the release wire (53) is connected to the second operation arm (5) via the spring (56).
It is erected and connected to 5). The state shown in FIGS. 8 and 2 is a state in which the operation lever (39) is operated to the neutral position (N), and the pin (55a) of the second operation arm (55) and the spring (56) are The space (A ₁ ) between the pin (53c) of the inner wire (53a) and the spring (56),
(A ₂ ) is occurring. The second operation arm (55) and the first operation arm (48) are helical springs (63).
Is urged clockwise by FIG. 8 and counterclockwise by FIG.

Operation As shown in Figure 2 the lever (39) back and forth axis (P ₂₎
For example, if you operate it by tilting it to the right side clutch disengagement side,
With the second swing arm (51) in contact with the pin (38b) and stopped, the first swing arm (50) is swing-operated by the pin (49a) of the second arm (49). Wire (53
a) is pulled and, conversely, the operating lever (39)
When the left side clutch is disengaged, the second swing arm (51) is swing-operated while the first swing arm (50) is stopped by the pin (38b). The inner wire (53a) is pulled with respect to the wire (53b). However, even if the operating lever (39) is oscillated between the right side clutch disengaged position and the left side clutch disengaged position, the accommodation (A ₁ ) in FIG.
(A ₂ ) only disappears (see FIG. 9), and within this range, the first switching valve (3
3) is operated and only the left and right side clutches (25L) and (25R) are turned on and off.

Then move the operating lever (39) to the left and right side clutch (25
L), (25R) beyond the cut position and operating to the right or left braking position, the inner wire (53a) pulls the first operation as shown in the state of FIG. 6 to the state of FIG. The arm (48) is oscillated and the spool (36a) of the variable relief valve (36) is pushed toward the throttle opening closing side by the first contact portion (48a) of the first operation arm (48). (No. 12
See figure). In this operation range, the spool (35a) of the second switching valve (35) is not in contact with the first operating arm (48), and the second switching valve (35) is internally provided with the detent mechanism (57).
And, the side brake (28) is held by the spring (58) on the hydraulic oil supply side (the spool (35a) rightward protruding side in FIGS. 6 and 10). Therefore, as shown in FIGS. 2 and 12, the braking force of the side brake (28) can be gradually increased by tilting the operation lever (39) from the left and right side clutch disengaged positions. Of.

When the operation lever (39) is tilted from the right or left braking position, the inner wire (53a) is further pulled, and as shown in the state of FIG. 10 to the state of FIG.
While the spool (36a) of the variable relief valve (36) is further pushed by the first contact part (48a) of the first operation arm (48), the second contact part (48b) of the first operation arm (48).
As a result, the spool (35a) of the second switching valve (35) is pushed in, causing the second switching valve (35) to reversely rotate the hydraulic clutch (30).
The crawler traveling device (24) is operated in the reverse direction while being decelerated to 1/2 by being operated on the hydraulic oil supply side (see FIGS. 2 and 12).

As shown in FIGS. 1 and 2, the operation lever (39)
And the third switching valve (37) for the support shaft (59) that swingably supports the frame body (38) around the left and right axis (P ₁ ), and the hydraulic cylinder (60) for raising and lowering the cutting section (6). ) Are mechanically interlocked with each other, and the reaper (6) can be moved up and down by swinging the operation lever (39) around the left and right axis (P ₁ ).

In addition, this machine is equipped with a check mechanism that prevents the operating lever (39) from operating to the right or left reverse position while traveling at high speed. A fan-shaped restraining member (65) is supported by being swingable around a core (P ₅ ), and biased counterclockwise on the paper surface by a spiral spring (64). On the other hand, in the hydrostatic stepless transmission (1), the first shift lever (66) for changing the swash plate angle and the check member (65) act as the inner wire (67a) of the release wire (67). Are connected through. The second shift lever (68) for sliding the shift gear (14) shown in FIG.
It is connected to the outer wire (67b) of 7).

With the above structure, when the first speed change lever (66) is operated to the high speed position (H ') side, the inner wire (67a) is pulled and the check member (65) is rotated clockwise in the drawing. 1 speed lever (66) high speed position (H ')
When the operation to the side is over the setting, the second operation arm (55)
The restraint member (65) enters into the locus of the pin (55b) inside. As a result, the first and second operation arms (48), (5
5) can be operated to the braking position (state shown in Fig. 10),
Further operation to the reverse rotation position (state shown in FIG. 11) cannot be performed by the contact of the pin (55b) with the check member (65).

The state shown in FIG. 8 is a state in which the first speed change lever (66) and the second speed change lever (68) are operated to the low speed positions (L ′), (L). When the second speed change lever (68) is operated to the medium speed position (M) and the high speed position (H), the outer wire (67b) is operated and the inner wire (67a) is pulled. Suppression member (6
5) rotates clockwise to the position corresponding to the medium speed position (M) and the high speed position (H). That is, as the second gear shift lever (68) corresponding to the sub gear shift is operated to the high speed side, the first gear shift lever (66) corresponding to the main gear shift from the low speed position (L ') to the high speed position (H'). When you go to
The state in which the operation lever (39) cannot be operated to the reverse rotation position appears earlier.

In the above embodiments, the left and right side gears (21L), (21R)
Is the position of engagement with the third gear (19) and the left and right fourth gear (26
L), (26R) has a structure that can be operated only in two positions of the occlusal position, the left and right side gears (21L), (21R) is the third gear (19) and the left and right fourth gear (26L), (26R) may be operated in an intermediate position that does not engage both.

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]

Drawing shows an embodiment of a steering structure of a work vehicle according to the present invention,
FIG. 1 is a hydraulic circuit diagram showing a connection state of first, second and third switching valves, a hydraulic cylinder and a variable relief valve in a combine, FIG. 2 is a perspective view showing a structure near an operating lever, and a third diagram.
FIG. 4 is a front view of the operating system of the first switching valve and the hydraulic cylinder, FIG. 4 is a vertical sectional side view showing the operating system of the first switching valve, FIG. 5 is a vertical sectional front view of the hydraulic cylinder, and FIG. FIG. 7 shows a switching valve, a variable relief valve and its operating system, which corresponds to a state in which the operating lever of FIG. 2 is operated to the neutral position, and FIG. 7 shows the operating system of the second switching valve and the variable relief valve. FIG. 8 is a vertical side view showing the operation system of the second switching valve and the variable relief valve, and FIG. 8 is a front view corresponding to a state where the operation lever of FIG. 2 is operated to the neutral position (rear view of FIG. 6). 9 is a front view of the operation system of the second switching valve and the variable relief valve corresponding to the case where the operation lever of FIG. 2 is operated to the right or left side clutch disengagement position, and FIG. 10 is the operation of FIG. The second switching valve, variable release, which corresponds when the lever is operated to the right or left braking position. Valves and longitudinal sectional front view of the operation system, the
Fig. 11 is a longitudinal sectional front view of the second switching valve, the variable relief valve and its operating system, which corresponds to the case where the operating lever of Fig. 2 is operated to the right or left reverse position, and Fig. 12 is the operation of the side brake and hydraulic clutch. FIG. 13 is a view showing a relationship between pressure and an operation angle around a longitudinal axis of an operation lever, FIG. 13 is a vertical sectional front view of a mission case in a combine, and FIG. 14 is a side view of a front half of the combine. (1) …… hydrostatic stepless transmission, (19) …… transmission side gear, (21R), (21L) …… side gear, (24) …… travel device, (26R), (26L) …… First braking gear, (27) ...
… Transmission shaft, (28) …… side brake, (29) …… second
Braking gear, (30) …… Reverse transmission mechanism, (62) …… Reverse gear.

Claims (2)

[Claims] 1. Separate side gears (21R), (21L) for transmitting power to respective traveling devices (24), (24) for left and right respectively.
Slide between the engagement position with the transmission side gear (19) and the engagement position with the pair of first braking side gears (26R), (26L) corresponding to the side gears (21R), (21L) respectively. A transmission shaft (27) that is freely configured and has a pair of second braking gears (29), (29), which are respectively engaged with the first braking gears (26R), (26L), in a fitted state. The transmission shaft (2
Acting on 7), both the first braking gears (26R), (26L)
And a single friction side brake (28) for braking the vehicle, and the power from the drive source side to both the first braking side gears (26R), (2
6L) reverse rotation transmission mechanism (30)
And a reversing transmission mechanism (30) capable of switching between a reversing transmission state and a non-transmission state. 2. The work vehicle according to claim 1, wherein the shift output from the hydrostatic continuously variable transmission (1) is transmitted in parallel to the transmission-side gear (19) and the reverse rotation transmission mechanism (30). Steering structure.