JPH089335B2 - Turning control structure of work vehicle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a structure for controlling turning of a work vehicle provided with a pair of left and right crawler type traveling devices and a multi-wheel work vehicle such as four wheels on one side.

[Conventional technology]

An example of the work vehicle as described above is a combine equipped with a crawler type traveling device. Some of such combines have a hydraulically operated braking mechanism that brakes one of the selected traveling devices, so that the braking mechanism brakes one of the traveling devices so that a turning operation can be performed. Is configured.

Since such a ground turning is performed by pushing the soil laterally by a crawler type traveling device, a great resistance is exerted from the ground. Therefore, since the engine may be stopped due to the resistance from the ground, the continuously variable transmission for traveling is automatically decelerated at the time of turning to avoid the engine from stopping. There is something.

[Problems to be Solved by the Invention]

When the automatic deceleration mechanism as described above is provided, the actuator (hydraulic cylinder, servo motor, etc.) that operates the continuously variable transmission to the deceleration side, the power source of the actuator (hydraulic pump, battery, etc.), Since a sensor that detects what is being done and a control means that operates the actuator based on the signal from the sensor are required, the structure becomes complicated as a whole, and improvement in terms of simplification of the structure There was room.

It is an object of the present invention to simplify the mechanism of automatic deceleration when turning a ground.

[Means for solving the problem]

A feature of the present invention is that the turning control structure of the work vehicle is configured as follows.

A shift mechanism and a manual operation tool in a continuously variable transmission for a pair of left and right traveling devices are interlockingly connected through a linkage mechanism to provide a holding mechanism capable of holding the manual operation tool at an arbitrary position, and the initial stage. The linkage mechanism is provided with an elastic accommodation mechanism that allows the shift operation unit to shift to the low speed side against the initial set pressure by applying a set pressure, and a hydraulic operation that applies braking to a selected one of the traveling devices. -Type braking mechanism, a hydraulic actuator that can operate the speed change operation part to the low speed side, and an oil passage that branches the hydraulic oil supplied to the braking mechanism in parallel and supplies it to the hydraulic actuator. When the pressure of the supplied hydraulic oil exceeds the set value, the hydraulic oil branched in parallel from this hydraulic oil causes
The hydraulic actuator is configured to operate the speed change operation unit toward the low speed side against the initial set pressure of the elastic accommodation mechanism.

In the continuously variable transmission for a pair of left and right traveling devices, the gear shift operation part and the manual operation tool are interlockingly connected through a linkage mechanism, and a friction holding mechanism that can hold the manual operation tool at an arbitrary position is provided. A hydraulically operated braking mechanism that applies braking to a selected one of the devices, a hydraulic actuator that can operate the manual operation tool to the low speed side, and hydraulic oil that is supplied to the braking mechanism in parallel to branch the hydraulic pressure. When the pressure of the hydraulic oil supplied to the braking mechanism exceeds the set value, with the oil passage for supplying to the actuator, the hydraulic oil branched in parallel from this hydraulic oil causes
The hydraulic actuator is configured to operate the manual operation tool toward the low speed side against the holding action of the friction holding mechanism.

[Work]

(I) With the configuration as described in the preceding paragraph, when hydraulic oil is supplied to the braking mechanism to make a turning turn, the pressure of the hydraulic oil to this braking mechanism increases, and the hydraulic oil with this high pressure is connected in parallel. The hydraulic oil is branched to be supplied to the hydraulic actuator, and the hydraulic actuator operates to automatically decelerate the continuously variable transmission.

In this case, the pressure of the hydraulic oil to the braking mechanism serves as a control unit that detects that the turning is being performed and issues an operation signal to the hydraulic actuator, and the hydraulic oil itself serves as a power source of the hydraulic actuator. . Therefore, a dedicated sensor, a control means, and a power source as a mechanism of instruction deceleration are unnecessary.

During the automatic deceleration of the hydraulic actuator, the elastic accommodation mechanism absorbs the mechanical displacement due to the automatic deceleration, and the holding mechanism holds the manual operation tool (shift lever or the like) in the operating position before the automatic deceleration. Therefore, when the solid turning is completed, the shift operation portion of the continuously variable transmission is returned to the original position (the position corresponding to the operation position of the manual operation tool) by the return action of the elastic accommodation mechanism. As a result, when the automatic deceleration is completed, the aircraft automatically returns to the original speed before the turning.

(Ii) With the configuration described in the preceding paragraph, as in the case of the preceding paragraph (see the description in the preceding paragraph (i)), a dedicated sensor, control means, and power source as a mechanism for automatic deceleration are unnecessary.

In this case, with the configuration of the preceding paragraph, at the time of turning to the ground, the manual operation tool linked to the speed change operation unit of the continuously variable transmission is operated to the low speed side by the hydraulic actuator to perform automatic deceleration. Therefore, even if the turning of the ground is completed, the manipulating tool remains operated to the low speed side due to the holding action of the friction holding mechanism, and the machine body maintains the low speed state during the turning of the ground. As a result, the operator may operate the manual operation tool toward the high speed side according to the situation after turning the ground.

〔The invention's effect〕

According to the present invention, by effectively utilizing the hydraulic oil supplied to the hydraulically operated braking mechanism, it is possible to omit a dedicated sensor, control means and power source as a mechanism for automatic deceleration. As a result, the structure could be simplified.

According to the first aspect of the invention, since the aircraft automatically returns to the speed before the turning of the turning point when the turning of the turning point is completed, the operability can be improved.

According to the second aspect of the present invention, by effectively utilizing the hydraulic oil supplied to the hydraulically operated braking mechanism, it is possible to omit the dedicated sensor, control means, and power source as an automatic deceleration mechanism. As a result, the structure could be simplified.

According to the second aspect of the present invention, after the turning of the ground at a low speed, depending on the condition of the ground and the work form after the turning of the ground,
The manual operation tool can be arbitrarily operated at a high speed side, and the workability can be improved.

〔Example〕

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

FIG. 5 shows the structure inside the transmission case (8) of the traveling system of the combine, which is one of the workers, in which the power from the engine (not shown) is a belt transmission mechanism (not shown) equipped with a tension clutch. Power) is transmitted to the input pulley (2) of the hydrostatic continuously variable transmission (1), and the power from the output shaft (3) of the hydrostatic continuously variable transmission (1) is transmitted to the first transmission shaft. It is transmitted from (4) via 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 power is transmitted to the second transmission shaft (11) first. The first high speed gear (12) is externally fitted so as to be relatively rotatable, and the shift gear (14) is externally fitted so as to have a spline structure. The second high speed gear (16) and the low speed gear (17) are fixed to the third transmission shaft (15), the first high speed gear (12) is meshed with the second high speed gear (16), and the third transmission The medium speed gear (18) is fixed to the 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 low speed gear (17), so that the power can be shifted to three stages of high, medium and low. This power is transmitted to the third gear (19) that meshes with the medium speed gear (18).

The right side gear (21R) and the left side gear (21L) are relatively rotatably externally fitted to the support shaft (20) that supports the third gear (19), and the right and left axles (22R) and (22L) are input. Gears (23R) and (23L) are replaced by right and left side gears (21R) and (2
1L) is always occluded. As a result, the right or left side gear (21R), (21L) is slidingly operated with respect to the third gear (19) to engage and separate from each other, and the drive sprocket (24a) of the crawler type traveling device (24) shown in FIG. ), The power transmission is turned on and off, and the side clutches (25R) and (25L) are formed between the third gear (19) and the right and left side gears (21R) and (21L). There is.

Next, the structure for braking one of the axles (22R) and (22L) will be described. As shown in FIG. 5, the support shaft (20)
The right fourth gear (26R) and the left fourth gear (26L) are rotatably supported relative to each other by a bearing, and the pair of fifth gears (29) fixed to the fourth transmission shaft (27) are connected to the right and left. 4th gear (26
R) and (26L) are engaged with each other, and a multi-plate hydraulically operated side brake (28) (corresponding to a braking mechanism) is provided at one end of the fourth transmission shaft (27). As a result, the right or left side gear (21R), (21L) is separated from the third gear (19) and engaged with the right or left fourth gear (26R), (26L), and the side brake (28) is operated. By doing so, braking can be applied to one of the axles (22R) and (22L), and this is a turning state.

Next, the structure for reversing one of the axles (22R) and (22L) will be described. As shown in FIG. 5, the third transmission shaft (1
A sixth gear (62) that meshes with the second high speed gear (16) of 5) is externally fitted to the fourth transmission shaft (27) so as to be rotatable relative to the sixth gear (62) and the fourth transmission shaft (27). ) And hydraulic clutch (3
0) is provided. As a result, the right or left side gear (21R), (21L) is engaged with the right or left fourth gear (26R), (26L) as described above, and the hydraulic clutch (3
When the 0) is turned on, the power from the second high speed gear (16) is rotated in the reverse direction and the speed is reduced to 1/2 and the axles (22R), (22L)
Is transmitted to, and this is a super-confidential turning state.

Next, a hydraulic oil supply structure for the hydraulic cylinders (31R), (31L), the side brakes (28), and the hydraulic clutch (30) for sliding the right and left side gears (21R), (21L) will be described. As shown in FIG. 6, the pump (3
The hydraulic fluid from 2) passes through the first switching valve (33) to the hydraulic cylinder (31R) for the right and left side gears (21R), (21L).
R), (31L) and hydraulic cylinders (31R), (3
The oil passage (34) from the side of (1L) is connected to the side brake (28) and the second switching valve (35) for the hydraulic clutch (30), and the side brake (28) and the hydraulic clutch (30) are connected to the oil passage (34). A variable relief valve (36) for 30) is connected. 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. As shown in FIG. 6, the operation lever (39) that can be operated in the front, rear, left and right, and the first
The switching valve (33), the second switching valve (35) and the variable relief valve (36) are mechanically linked, and for example, the operating lever (39) is moved from the neutral position (N) to the right or left first turning position ( When operated to R ₁ ), (L ₁ ), only the first switching valve (33) is operated and the hydraulic cylinders (31R), (31L) are operated via the right or left operation part (46R), (46L). , 3rd gear (19)
The right or left side gears (21R) and (21L) that were engaged with the left side are separated from the third gear (19), and the right or left fourth gear (26
R), (26L).

In this case, the variable relief valve (36) is fully open,
The side brake (28) and hydraulic clutch (30) are in the disengaged state, so the right or left axle (22R), (22L)
To the side clutch (25R), (2
(5L) turned off) and the aircraft slowly turns to the right or left. Sequence valve (47) provided in the oil passage (34)
Secures in the hydraulic cylinders (31R), (31L) the pressure necessary for the right or left side gears (21R), (21L) to completely mesh with the right or left fourth gears (26R), (26L). It is for doing.

Next, move the operating lever (39) from the right or left first turning position (R ₁ ), (L ₁ ) to the right or left second turning position (R ₂ ),
(L ₂ ) as you move to the right or left side gear (21
R) and (21L) are engaged with the right or left fourth gear (26R) and (26L), and the second switching valve (35) is the side brake (28).
The variable relief valve (36) is gradually operated from the fully open state to the closed side while being operated on the hydraulic oil supply side. As a result, the side brake (28) starts to act and the right or left axle (22R), (22L) is gradually braked, and the aircraft turns right or left. 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 and the hydraulic clutch (30) is engaged, the right or left axles (22R), (22L) are driven in reverse, and the aircraft is superposed to the right or left. Turn around the ground.

The third switching valve (37) for the hydraulic cylinder (60) for raising and lowering the reaper (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 shift operation structure of the hydrostatic continuously variable transmission (1) will be described. As shown in FIGS. 1 and 3, a bracket (13) is swingably supported around a horizontal axis (P ₁ ) in the body control section, and the bracket (13) has a gear shift lever (38) ( Equivalent to the artificial operation tool) is attached. As shown in FIG. 1, a hydrostatic continuously variable transmission (1)
The gear shift operation arm (40) (corresponding to the gear shift operation section) is fixed to the trunnion shaft (1a) of the gear shift operation arm (40).
And the first arm (13a) of the bracket (13),
A link rod (41) (corresponding to a link mechanism) is installed.

As shown in FIG. 3, a thin disk-shaped ring gear (43) is fixed to a boss portion (42) on which a bracket (13) is relatively rotatably fitted, and the ring gear (43) is attached to the boss portion (42) of FIG. As shown in, a servo motor (44) for vehicle speed control described later.
Drive gear (44a) is engaged. Brackets (13)
The friction plate (45) is sandwiched between the ring gear (43) and the ring gear (43), and a disc spring (48) (corresponding to a holding mechanism) that presses the bracket (13) toward the ring gear (43) is provided. .

With the above structure, the servo motor (44) is stopped when the vehicle speed control is not performed, and the ring gear (43) is a fixed member. Therefore, the operator can
By operating the, the hydrostatic stepless transmission (1) can be artificially shifted, and even if the operator releases his / her hand from the shift lever (38) at a certain operating position, the disc spring (48)
The shift lever (38) is held in its operating position by the urging force of the.

Next, the structure of vehicle speed control using the servo motor (44) will be described. This vehicle speed control detects the number of revolutions of an engine (not shown), obtains a work load based on this number of revolutions, and uses a ring gear (43) by a servo motor (44) so that the work load is maintained within a set range. ) Is rotated to operate the speed change operation arm (40) of the hydrostatic continuously variable transmission (1) via the bracket (13). In this case, a potentiometer (49) for detecting the angle of the bracket (13) and feeding it back to a control device (not shown) is provided. As shown in FIGS. 1 and 3, the pin (49b) at the tip of the rotary detection arm (49a) of the potentiometer (49) is inserted into the elongated hole (13c) of the second arm (13b) of the bracket (13). The angle of the bracket (13) is detected as the angle of the detection arm (49a).

An elastic accommodation mechanism (50) is provided in the middle of the linking rod (41). Next, the structure of the elastic accommodation mechanism (50) will be described. As shown in FIG. 1, the linking rod (41) is connected to the upper rod (41a) connected to the bracket (13) and the speed change operation arm (40) of the hydrostatic continuously variable transmission (1). The lower rod (41b)
The cylindrical member (50a) is fixed to the upper rod (41a).
The receiving member (50) fixed to the upper end of the lower rod (41b)
The spring (50d) is attached between the b) and the ring member (50c) fixed to the lower end of the cylindrical member (50a) in a state compressed more than its natural length. This allows the shift lever (38) and the servomotor (44) to perform a shift operation.
The spring (50d) does not contract when the vehicle speed is controlled by, and the angle of the bracket (13) corresponds to the position of the speed change operation arm (40).

When controlling the vehicle speed by the servo motor (44),
As shown in the figure, after the speed change operation arm (40) of the hydrostatic stepless transmission (1) reaches the forward maximum speed position (F _MAX ) (the speed change operation arm (40) does not move any further). When the servo motor (44) tries to move the bracket (13 to the high speed side, the spring (50d) of the elastic accommodation mechanism (50) contracts so that this operation can be performed. When the bracket (13) is slightly moved to the higher speed side after the (40) reaches the maximum speed position (F _MAX ), this operation is detected by the potentiometer (49) and the servo motor (44) is stopped. As a result, the hydrostatic continuously variable transmission (1) is controlled during vehicle speed control.
Can be used without waste from the neutral position (N) to the highest speed position on the forward side (F _MAX ).

Next, a configuration for automatically decelerating the hydrostatic continuously variable transmission (1) at the time of solid turning using the side brake (28) and at the time of super-sight turning using the hydraulic clutch (30). Will be described. As shown in FIGS. 1 and 4, the operating member (51) having a T-shaped cross section and the lower rod (41b) of the linking rod (41) have one bolt at the tip of the speed change operating arm (40). It is attached by (52). Operating member (51)
An L-shaped member (51a) like a bent bar is fixed to the hydraulic cylinder (5a) above the L-shaped member (51a).
3) (equivalent to hydraulic actuator) is installed.
As shown in FIG. 6, the oil passage (5
4) is connected to the hydraulic cylinder (53), and as shown in FIG. 1, the hydraulic cylinder (53) is internally provided with a spring (53b) for urging the piston (53a) toward the retracting side.

With the above structure, when the side brake (28) or the hydraulic clutch (30) is turned on during forward movement when the speed change lever (38) is operated to a certain operating position, a turning turn or a super turning turn is performed. The pressure in the oil passage (34) in FIG. 6 increases. Therefore, the high-pressure hydraulic oil in the oil passage (34) is supplied to the hydraulic cylinder (53) via the oil passage (54). This allows
As shown in FIG. 2, the piston (53a) extends and contacts the L-shaped member (51a), so that the speed change operation arm (40) of the hydrostatic continuously variable transmission (1) is moved to the neutral position (N). Push it down to
The hydrostatic continuously variable transmission (1) is automatically decelerated. When the gear shift operation arm (40) is operated in this way, only the spring (50d) of the elastic accommodation mechanism (50) is compressed, and the gear shift lever (38) does not move due to the holding action of the disc spring (48). .

When the side brake (28) or the hydraulic clutch (30) is disengaged (the variable relief valve (36) is returned to the full open state) after the turning or super turning is completed, the oil passage (3
The pressures of (4) and (54) decrease, and the piston (53a) is retracted upward by the spring (53b) of the hydraulic cylinder (53). As a result, the spring (50d) of the elastic accommodation mechanism (50) is extended, and the shift operation arm (40) of the hydrostatic stepless transmission (1) is moved to a position corresponding to the operation position of the shift lever (38). Automatically return to.

As described above, in this structure, the elastic accommodation mechanism (50) is
This is a versatility to use the hydrostatic continuously variable transmission (1) from the neutral position (N) to the forward-side maximum speed position (F _MAX ) without waste during vehicle speed control by the servo motor (44), and It is also a versatility for automatic deceleration at the time of ground turning and super turning, and has both functions.

In this embodiment, the hydrostatic continuously variable transmission (1) is used as the continuously variable transmission, but a belt type continuously variable transmission may be used instead. Although the structure for holding the speed change lever (38) at an arbitrary position is the friction holding structure by the disc spring (48), the speed change lever (38) is provided with a lever guide (not shown) having a plurality of sets of recesses. May be engaged with and held by this lever guide. Further, the present invention can be applied to not only a work vehicle equipped with a crawler type traveling device (24) but also a 6-wheel type or 8-wheel type wheeled vehicle.

[Another embodiment]

As shown in FIG. 8, an L-shaped member (13d) like a bent bar is fixed to the second arm (13b) of the bracket (13) so as to face the L-shaped member (13d). A hydraulic cylinder (53) may be arranged in the. In this case, the holding mechanism provided on the speed change lever (38) is not the engagement holding structure by the lever guide, but a friction holding mechanism using a disc spring (48) or the like. The other structure is the same as that of the above-mentioned embodiment.

As a result, the piston (53a) of the hydraulic cylinder (53) extends and becomes the L-shaped member (13d) at the time of the solid turning or the super turning using the side brake (28) or the hydraulic clutch (30). Abut the bracket (13) and gearshift (3
8) is operated to the neutral position (N) side, and the hydrostatic continuously variable transmission (1) is decelerated.

Piston (53a) after the end of turning or super turning
Even if is retracted, the gear shift lever (38) remains operated at the low speed side due to the friction holding action of the disc spring (48). Therefore, in order to return to the predetermined speed before the turning or super turning, the operator has to operate the shift lever (38) again to the high speed side.

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 a turning control structure for a work vehicle according to the present invention, FIG. 1 is a side view showing a structure for linking a speed change lever and a hydrostatic continuously variable transmission, and FIG. 2 is shown in FIG. From the state, a side view showing a state in which the hydrostatic continuously variable transmission is decelerated by a hydraulic cylinder, FIG. 3 is a cross-sectional plan view near a bracket supporting a gearshift lever, and FIG. 4 is a hydrostatic continuously variable transmission. 5 is a vertical sectional rear view of the tip of the gear shift operation arm in FIG.
The figure shows a vertical front view of the mission case, and Fig. 6 shows the first, second, and third.
FIG. 7 is a hydraulic circuit diagram of the switching valve and the variable relief valve, FIG. 7 is an overall side view of the combine, and FIG. 8 is a side view showing a linkage structure of a shift lever and a hydrostatic continuously variable transmission according to another embodiment. (1) …… continuously variable transmission, (24) …… traveling device, (28)
...... Brake mechanism, (38) ...... manual operation tool, (40) ...... Gear shift operation part of continuously variable transmission, (41) ...... Coupling mechanism, (48) ...
… Holding mechanism (friction holding mechanism), (50) …… elastic accommodation mechanism, (53) …… hydraulic actuator, (54) …… oil passage.

Continuation of front page (56) Reference JP-A-63-13866 (JP, A) JP-A-63-53181 (JP, A) JP-B 57-22766 (JP, B2) JP-B 57-60977 (JP , B2)

Claims (2)

[Claims] Claim: What is claimed is: 1. A pair of left and right traveling devices (24), a continuously variable transmission (1) for a continuously variable transmission (1), and a manual operation tool (38) between a speed change operation section (40) and an artificial operation tool (38) via a linkage mechanism (41). Is provided with a holding mechanism (48) capable of holding the manual operation tool (38) at an arbitrary position by interlocking with each other, and an initial setting pressure is applied to the shift operating section () against the initial setting pressure. An elastic accommodation mechanism (50) that allows the shift of the gear (40) to the low speed side is provided in the linkage mechanism (41), and a hydraulic operation for braking one selected one of the traveling devices (24), (24). Type braking mechanism (28), a hydraulic actuator (53) capable of operating the speed change operation part (40) to a low speed side, and hydraulic oil supplied to the braking mechanism (28) are branched in parallel to each other. A hydraulic oil (54) for supplying to the hydraulic actuator (53), and the pressure of the hydraulic oil supplied to the braking mechanism (28). Is greater than or equal to a set value, the hydraulic oil branched in parallel with the hydraulic oil resists the initial set pressure of the elastic accommodation mechanism (50) to cause the hydraulic actuator (53) to move to the speed change operation section (40). A turning control structure for a work vehicle that is configured to be operated at a low speed side. 2. A pair of left and right traveling devices (24), a continuously variable transmission (1) for a continuously variable transmission (1), and a manual operation tool (38) between a speed change operation section (40) and an artificial operation tool (38) via a linkage mechanism (41). Is provided with a friction holding mechanism (48) capable of holding the manual operation tool (38) at an arbitrary position and braking the selected one of the traveling devices (24) and (24). A hydraulically operated braking mechanism (28) to be applied, a hydraulic actuator (53) capable of operating the manual operation tool (38) at a low speed side, and hydraulic oil supplied to the braking mechanism (28) are branched in parallel. And an oil passage (54) for supplying to the hydraulic actuator (53), and when the pressure of the hydraulic oil supplied to the braking mechanism (28) reaches or exceeds a set value, the hydraulic oil is branched in parallel from the hydraulic oil. By the hydraulic oil that has been created, against the holding action of the friction holding mechanism (48),
The hydraulic actuator (53) is the artificial operation tool (38).
A turning control structure for a work vehicle that is configured to be operated at a low speed side.