JPH0456686A - Transport vehicle - Google Patents

Abstract

PURPOSE:To enable the stable switching operation of side clutches and a side brake by making use of the characteristic of a flow priority valve at the time of feeding operating oil independently to two sets of devices of different characteristics, that is, the side clutches and side brake, and a cargo handling hydraulic device. CONSTITUTION:In a dolly provided with a pallet 6 at the rear part of a body supported by a pair of right and left rubber crawler type travel devices, the pallet 6 can be lifted around a lateral axis P1. There is provided a hydraulic circuit having a side brake 28 for braking one travel device on the transmission cut-off side by side clutches 31L, 31R for cutting off transmission to one travel device selected between a pair of right and left travel devices. In this case, an oil passage from a pump 32 driven by an engine 13 is connected to a flow priority valve 42, and the excess flow oil passage 43 of this valve 42 is connected to a hydraulic cylinder 7 through an elevation switching valve 44. An oil passage 45 for controlled flow is connected to the first change-over valve 33 of the side clutches 31R, 3lL.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transport vehicle equipped with a pair of left and right traveling devices, such as a crawler type or four wheels on one side, and a hydraulic system for cargo handling work.

[Conventional technology]

An example of the above-mentioned transport vehicle is Utility Model 61-152527.
It is disclosed in the publication No. This is an 8-wheel type with four wheels on each side, and each wheel cannot be steered, and the four wheels on one side are considered as one traveling device.

In this case, the vehicle is equipped with a side clutch that cuts off power transmission to a selected one of the pair of left and right running gears to perform a slow turn, and a handbrake that applies braking to the running gear on the transmission-disconnected side to perform a pivot turn. .

[Problem to be solved by the invention] The aforementioned side clutch and handbrake are mechanically linked to the operating lever and operating pedal by a link mechanism, etc., and important operations cannot be performed by the operator's artificial operating force. There is. In this case, since important operations of the side clutch and handbrake are difficult for the driver, it has been proposed to perform important operations of the side clutch and handbrake using hydraulic pressure.

An object of the present invention is to enable stable on/off operations to be performed without waste when important operations of a side clutch and a side brake are performed using hydraulic pressure.

[Means to solve the problem]

A feature of the present invention is that a transport vehicle equipped with a pair of left and right traveling devices and a hydraulic device for cargo handling is configured as follows. That is, it includes a hydraulically operated side clutch that cuts off power transmission to a selected one of the traveling devices, and a hydraulically operated side brake that applies braking to the traveling device on which the transmission is cut off by the side clutch. With,
The hydraulic oil from the pump is branched by a flow priority valve, the controlled flow is supplied to the side clutch and the hand brake, and the surplus flow is supplied to the hydraulic system for cargo handling work. The functions and effects are as follows.

[For production]

The hydraulically operated side clutches and handbrakes described above may require a small flow of hydraulic oil, or may require a stable supply of a certain amount of hydraulic oil.

On the other hand, hydraulic systems for cargo handling work (for example, loading platforms, crane lifting devices, etc.) require a large flow of hydraulic oil because of heavy load work.

Therefore, if the control flow from the flow priority valve is supplied to the side clutch and handbrake as described above, a constant amount of hydraulic fluid will be supplied regardless of changes in engine speed and pump discharge volume. This allows stable and important operation of the side clutch and handbrake.

Further, the flow rate of the surplus flow of the flow priority valve changes depending on changes in engine speed, etc., or the flow rate is generally larger than that of the control flow. Therefore, by supplying this surplus flow to the hydraulic system for cargo handling work, this hydraulic system can perform heavy load work without any problems.

〔Effect of the invention〕

As mentioned above, when hydraulic oil is separately supplied to two sets of devices with different characteristics (the side clutch and handbrake, and the hydraulic system for cargo handling), by making good use of the characteristics of the flow priority valve, it is possible to A transport vehicle has been obtained that allows stable and important operation of the clutch and handbrake and unhindered loading and unloading work at the same time without waste.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

As shown in Fig. 3, a control section (5) is located at the front of the aircraft, which is supported by a pair of left and right rubber crawler type traveling devices (24).
A carrier is constructed by providing a loading platform (6) at the rear of the aircraft. The loading platform (6) can be lifted around the transverse axis (P,) at the rear of the aircraft, and is equipped with a hydraulic cylinder (7) (corresponding to a hydraulic system for cargo handling work) for this lifting operation.

Next, the transmission structure for traveling and the structure inside the transmission case (8) will be explained. As shown in FIGS. 2 and 1, power from the engine (13) is transmitted to the input pulley (2) of the hydrostatic continuously variable transmission (1) via a belt transmission mechanism (48) equipped with a tension clutch. transmitted to. This hydrostatic continuously variable transmission (1) includes an axial plunger type hydraulic pump (37) driven by the power of an engine (13) and a hydraulic motor (38) on the output side. It has a structure in which a pair of oil passages (40) are connected across the hydraulic motor (38) and the hydraulic motor (38).

As shown in Fig. 2, the power from the output shaft (3) of the hydrostatic continuously variable transmission (1) is transmitted from the first transmission shaft (4) to the first gear (9) and the second gear (10). via the second transmission shaft (
11). This second transmission shaft (11) has a first
A high-speed gear (12) is fitted onto the outside so as to be relatively rotatable, and
A shift gear (14) is slidably fitted onto the outside with a spline structure. On the other hand, the third transmission shaft (15)
A second high speed gear (16) and a low speed gear (17) are fixed to the second high speed gear (16), and the first high speed gear (12) meshes with the second high speed gear (16).

Further, a medium speed gear (18) is fixed to the third transmission shaft (15).

With the above structure, by sliding the shift gear (14) and engaging it with the first high speed gear (12), medium speed gear (18), and low speed gear (17), the power can be shifted into three stages: high, medium and low. This power is transmitted to the third gear (19) which meshes with the medium speed gear (18).

On the support shaft (20) that supports the third gear (19), a right side gear (21R) and a left side gear (21L) are fitted on the outside so as to be relatively rotatable, and left and right axles (22L),
The input gears (23R) and (23L) of (22R) are always engaged with the left and right side gears (21L) and (21R).

This allows the right or left side gear (21R), (21
L) is slid against the third gear (19) to perform occlusal and
The third gear (19), left and right side gears (21L), and the drive sprocket (24a) of the rubber crawler type traveling device (24) shown in FIG. (21R) constitute side clutches (25R) and (25L).

Next, a structure for applying braking to one axle (22R) or (22L) will be explained. As shown in the figure, the support shaft (
20), right 4th gear (26R) and left 4th gear (26L)
) is relatively rotatably supported on a bearing, and the fourth
A pair of fifth gears (29) fixed to the transmission shaft (27) mesh with the right fourth gear (26R) and the left fourth gear (26L). A multi-plate hydraulically operated side brake (28) is provided at one end of the fourth transmission shaft (27).

As a result, the right side gear (21R) or left side gear (21L) is separated from the third gear (19) and engaged with the right fourth gear (26R) or left fourth gear (26L), and the hand brake (28) is activated. By turning on the brake, it is possible to apply braking to one of the axles (22R) or (22L). This is the turning state.

Next, a structure for reversing one axle (22R) or (22L) will be explained. As shown in the figure, the sixth gear (
A hydraulic clutch (30) is provided between the sixth gear (62) and the fourth transmission shaft (27). As a result, the right side gear (21R) or left side gear (21L)
) is engaged with the right 4th gear (26R) or the left 4th gear (26L) as described above, and then press the hydraulic clutch (30).
When the second high-speed gear (16) is turned on, the power from the second high-speed gear (16) is transmitted to the axle (22R) or (22L) in a reverse state and at a speed reduced to 1/2. And this is the state of super confidence turning.

Next, the hydraulic cylinders (31R) and (31L) are used to slide the left and right side gears (21L) and (21R).
), the hand brake (28), the hydraulic clutch (30), and the hydraulic circuit structure for the hydraulic cylinder (7) for the cargo platform (6). As shown in Fig. 1, an oil line (41) from a pump (32) driven by the power of an engine (13) is connected to a flow priority valve (42), and the flow priority valve (42) has a surplus. The diversion oil passage (43) is connected to the loading platform (6) via the lift switching valve (44).
) is connected to the hydraulic cylinder (7).

Thereby, by operating the lift switching valve (44), the loading platform (6) can be lifted or lowered.

Oil passage (4) for control flow of flow priority valve (42)
5) is the hydraulic cylinder (31R) for the side clutch (25R), (25L), the first switching valve (31L) (
33). And the hydraulic cylinder (31
R).

(31L) is connected to the second switching valve (35) for the hand brake (28) and the hydraulic clutch (30), and the oil path (34) is connected to the hand brake (28) and the hydraulic clutch (30). A variable relief valve (36) is connected to the hydraulic clutch (30). Also, pump (4
6) is for supplying hydraulic oil to the hydrostatic continuously variable transmission (1).

Next, the operations of the first switching valve (33), the second switching valve (35), and the variable relief valve (36) will be explained. As shown in Figure 1, the control lever (39) that can be operated left and right and the
The switching valve (33), the second switching valve (35), and the variable relief valve (36) are mechanically linked.
Or, when operated to the left first turning position (Ll), only the first switching valve (33) is operated and the hydraulic cylinder (31R) or (31L) is operated via the right or left operating arm (not shown). The right or left side gear (21R), (21L) that was engaged with the third gear (19) is separated from the third gear (19), and the right or left fourth gear (26R), (26L) is moved away from the third gear (19).
) to bite.

In this case, the variable relief valve (36) is in a fully open state,
Since both the handbrake (28) and hydraulic clutch (30) are in the disengaged state, the right or left axle (22)
R), (22L) is cut off (side clutch (25R) or (25L) is disengaged),
The aircraft makes a slow turn to the right or left.

In addition, a sequence valve (47) provided in the oil passage (34)
) is the pressure required for the right or left side gear (21R), (21L) to completely engage the right or left fourth gear (26R), (26L), the hydraulic cylinder (31R),
(31L).

Next, move the operating lever (39) to the right or left first turning position (R1
), from (Ll) to the right or left second turning position (R2),
(Ll), the right or left side gear (21
R).

(21L) is the right or left 4th gear (261?), (26
L) and the second switching valve (35) is operated to supply hydraulic oil to the handbrake (28), the variable relief valve (36) is gradually operated from the fully open state to the closed side. I'm going to be done. As a result, the handbrake (28) begins to act, and the right or left axle (22R) or (22L) is gradually braked, and the aircraft turns to the right or left. Then, the second right or left of the operating lever (39)
The braking force of the handbrake (28) is maximum at the turning positions (R2) and (Ll).

Next, move the operating lever (39) to the right or left third rotation position (R
, ), (Ll), the second switching valve (35) is switched to the hydraulic oil supply side to the hydraulic clutch (30) in the state described above. This allows the handbrake (
28) is in the disengaged state, and the hydraulic clutch (30)
is engaged and the right or left axle (22R), (22
L) is driven in reverse, and the aircraft makes a sharp turn to the right or left.

Further, as shown in FIG. 1, it is connected to an oil passage (49) for surplus flow from the pump (46) or an oil cooler (51). In addition, the oil passage (52) from the mission case (8)
) and an oil passage (50) for draining oil from the elevation switching valve (44)
are joined together and connected to a pump (32).

The present invention is applicable not only to a transport vehicle equipped with a rubber crawler type traveling device (24) but also to a wheeled transport vehicle with four wheels on one side.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the transport vehicle according to the present invention, and FIG. 1 is a hydraulic circuit diagram for traveling and loading platform. FIG. 2 is a longitudinal sectional front view of the mission case, and FIG. 3 is an overall side view of the transport vehicle. (7)...Hydraulic system, (24)...Traveling device, (25R), (25L)...2 side clutch, (28)... side brake,(
32)...Pump, (42)...Flow priority valve.

Claims (1)

[Claims] A transport vehicle equipped with a pair of left and right traveling devices (24), (24) and a hydraulic device (7) for cargo handling work, wherein one of the traveling devices (24), (24) is selected. Hydraulically operated side clutch (25R) that cuts off power transmission to (2
5L) and the side clutch (25R), (25L)
The traveling device (24), (24) on the side where the transmission was cut off due to
It is equipped with a hydraulically operated hand brake (28) that applies braking to the side clutch (25R), the hydraulic oil from the pump (32) is branched by a flow priority valve (42), and the control flow is distributed to the side clutch (25R), ( 25L) and a handbrake (28), and the surplus flow is supplied to the hydraulic system (7) for cargo handling operations.