JPH0735880Y2 - Bulldozer excavator - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a soil discharging device for a bulldozer.

[Conventional technology]

As a conventional soil discharging device of this type, there is an invention disclosed in Japanese Patent Publication No. 50-3123.

According to the present invention, a central portion of a blade and a central portion of a U-shaped support frame are connected by a universal ball joint, and a pair of left and right double acting cylinders are provided between both side portions of the support frame and both end sides of the blade. A triangular double-sided mounting portion is formed, and further, a third double-acting cylinder for stably holding the posture of the three-point mounting blade is provided, and a pair of left and right double-acting cylinders are used to angle and pitch the blades. The double-acting cylinder of No. 3 tilted the blade.

[Problems to be solved by the device]

In the case of the above configuration, the left and right double-acting cylinders are equipped with a switching valve in order to simultaneously control the expansion and contraction of the left and right double-acting double-angle cylinders to operate the pitching attitude of the blades. Without switching the hydraulic circuit in parallel with the series, the angle and pitch of the blade could not be obtained, and the switching operation structure was complicated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an excavator for a bulldozer in which the angle, tilt, and pitch actions of the blade can be easily obtained and the switching operation structure can be simplified. Especially.

[Means for Solving the Problems]

In order to achieve the above object, the present invention provides a port relief valve and a suction valve in a parallel circuit that connects the head side of the left (right) angle cylinder and the bottom side of the right (left) angle cylinder, respectively. Angle cylinder circuit,
The tilt cylinder circuit connecting the tilt cylinder to the tilt (pitch) switching valve and the pitch cylinder circuit connecting the pitch cylinder to the tilt (pitch) switching valve are arranged in parallel, and electromagnetic valves are provided in the tilt cylinder circuit and the pitch cylinder circuit, respectively. And a circuit configuration.

[Action]

A pitch cylinder circuit dedicated to the pitch action of the blade is provided, and the pitch cylinder circuit expands and contracts as a tilt (pitch) switching valve, and the angle cylinder circuit is made into a parallel circuit to restrain the angle hydraulic pressure at the blade pitch. Release is performed by the port relief valve and the suction valve.

〔Example〕

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

FIG. 1 shows the overall structure of a bulldozer earthmoving device according to the present invention. In FIG. 1, reference numeral 1 denotes a U-shaped support frame, and the left and right rear ends of the support frame 1 are the main frames of the bulldozer ( (Not shown) via a pin.

A support shaft 2 is fixed to the center of the front side of the support frame 1, side support members 3 and 3'are provided on the upper surfaces of the left and right sides of the support frame 1, and further on the upper surface of the front side of the support frame 1. Are each provided with a central support 4.

The support shaft 2 of the support frame 1 is attached to a bracket 7 at the lower center of the rear surface of the blade 6 via a ball joint 8, and left and right angle cylinder mounting brackets 9 and 9'are attached to the rear surface of the blade 6. A tilt cylinder mounting bracket 10 and a pitch cylinder mounting bracket 11 are provided.

The piston rods 13 and 13 'of the lift cylinders 12 and 12', which are swingably provided on the left and right sides of the vehicle body of the bulldozer, are attached to the upper ends of the side support members 3 and 3'by pins 14 and 14 '. In addition, the base ends of the left and right angle cylinders 15 and 15 'are attached to the lower portions of the side support members 3 and 3'by pins 16 and 16'.
The piston rods 17 and 17 'of the angle cylinders 15 and 15' are attached to the angle cylinder mounting brackets 9 and 9'of the blade 6, respectively.
It is attached to pins 18 and 18 '. Also, the central support 4
Mounting brackets 19 and 20 are fixedly attached to the lower rear surface and the upper front surface, and the base of the pitch cylinder 21 is mounted to the mounting bracket 19 with pins 22. The piston rod 23 of the pitch cylinder 21 has the pitch of the blade 6 It is attached to the cylinder mounting bracket 11 with pins 24. Also, the blade 6
The tilt cylinder mounting bracket 10 has a tilt cylinder
The base of 25 is attached with pin 26, this tilt cylinder
The piston rod 27 of 25 is a mounting bracket of the central support 4
It is attached to 20 with pin 28. Both ends of the angle cylinder, pitch cylinder, and tilt cylinder are provided with spherical bushes.

Fig. 3 shows the hydraulic circuit of the soil discharging device. 30 in this hydraulic circuit
Is an angle switching valve, 31 is a tilt (pitch) switching valve, and 32 is a lift switching valve.

The pump ports 30a and 30b of the angle switching valve 30 are connected to the discharge side of the pump 35 by the pipes 33 and 34, and the pipe 3
A check valve 36 is provided at 4. The port 30c of the angle switching valve 30 is connected to the bottom side of the left angle cylinder 15 and the head side of the right angle cylinder 15 'via a pipe 37, and the port 30d is connected to the left angle via a pipe 38. It is connected to the head side of the cylinder 15 and the bottom side of the right angle cylinder 15 '. Also, the tank port of the angle control valve 30
30e communicates with the tank 40 through a pipe 39, and the bottom side of the left angle cylinder 15 and the head side of the right angle cylinder 15 'incorporate a port relief valve 41 and a suction valve 42 in parallel. It communicates with the tank 40 through a pipe line 43, and the head side of the left angle cylinder 15 and the bottom side of the right angle cylinder 15 'have a port relief valve 44 and a suction valve.
It communicates with the tank 40 via a conduit 46 in which 45 and 45 are installed in parallel. The discharge side of the pump 35 communicates with the tank 40 via a pipe line 48 having a relief valve 47.

The port 30f of the angle switching valve 30 is connected to the pump ports 31a and 31b of the tilt (pitch) switching valve 31 via the pipes 49 and 50, and the pipe valve 50 is provided with the check valve 51. A tilt cylinder circuit 52 that connects the tilt (pitch) switching valve 31 and the tilt cylinder 25 and a pitch cylinder circuit 53 that connects the tilt (pitch) switching valve 31 and the pitch cylinder 21 are arranged in parallel. Solenoid valve
54, and the pitch cylinder circuit 53 is provided with an electromagnetic opening / closing valve 55.

That is, the port 31c of the tilt (pitch) switching valve 31 is connected to the port 54a of the electromagnetic opening / closing valve 54 via the pipe 56, and the port 31a is connected to the port 55a of the electromagnetic opening / closing valve 55 via the pipe 57. It is connected.

Further, the port 31d of the tilt (pitch) switching valve 31 is connected to the port 54b of the electromagnetic opening / closing valve 54 via the pipe 58, and the port 31d is connected to the port 55b of the electromagnetic opening / closing valve 55 via the pipe 59. There is. Ports 54c and 54d of the solenoid on-off valve 54 are pipes 60,
It is connected to the tilt cylinder 25 via 61, and the ports 55c and 55d of the electromagnetic on-off valve 55 are connected to the pitch cylinder 21 via conduits 62 and 63. Then, the pipes 60, 62 are squeezed 64,
65 is provided.

Further, the port 31e of the tilt (pitch) switching valve 31 is connected to the pipe 66,
It is connected to the pump ports 32a and 32b of the lift switching valve 32 via 67, and the tank port of the tilt (pitch) switching valve 31.
The 31f communicates with the tank 40. Lift switching valve 32 port 3
2c and 32d are connected to the lift cylinders 12 and 12 'via pipes 68 and 69, and the bottom side of the lift cylinders 12 and 12' communicates with the tank 40 via a pipe 71 having a suction valve 70. And the tank port 32c leads to the tank 40.

Next, the operation will be described. The tilt (pitch) switching valve 31 is switched to put the position A on the port side, the electromagnetic on-off valve 54 is closed, and the electromagnetic on-off valve 55 is opened to extend the pitch cylinder 21 and extend the front pitch of the blade 6. To act.

Further, the tilt (pitch) switching valve 31 is switched to put the position B on the port side and the electromagnetic on-off valve 54 is closed, so that the electromagnetic on-off valve is closed.
Pitch cylinder 21
Is reduced to perform the rear pitch action of the blade 6. However, the pitch action always involves the expansion and contraction of the angle cylinders 15 and 15 '. In the tilting operation, the electromagnetic on-off valve 54 is opened, the solenoid 55 is closed, and the tilt (pitch) switching valve 31 is switched to obtain a tilting action.

Next, the pitch operation under each condition will be described.

In case of no angle load and front pitch As shown in Fig. 4, when there is no load that causes angle, when the blade 6 is operated in front pitch, oil is sucked from the left and right suction valves 42, 45 and the angle cylinder 15, 15 ′
Pitches before stretching.

With angle load and front pitch When a load F that causes the blade to be angled as shown in Fig. 5 is used, the angle cylinders 15 and 15 'produce a force that balances this load F. Pressure is applied to the bottom side of the cylinder 15 and the head side of the right angle cylinder 15 '.

Angle cylinder due to the extension of pitch cylinder 21
Although 15 and 15 'are extended, oil cannot be sucked from the suction valve 42 on the left side.

As a result, the stroke ratio of the left and right angle cylinders 15 and 15 'is Becomes Insufficient amount of oil is sucked in through the suction valve 45 on the right side.

That is, it may be considered that the pitch operation is performed on the pitch axis S shown in FIG. However, at this time, the descending amount of the blade edge due to the pitch is left side> right side (right tilt). The amount of movement to the rear is also left side> right side.

No angle load, rear pitch As shown in Fig. 7, when there is no angle load, oil is released from both port relief valves 41 and 44, and after angle cylinders 15 and 15 'contract. To pitch.

At this time, the pitch cylinder 21 is the angle cylinder 15,1
It is enough to overcome the difference between the bottom area of 5'and the head area (piston rod area) x port relief set pressure.

When there is an angle load and there is a rear pitch, there is pressure as in the case where there is a load F that causes an angle as shown in FIG.

Further, due to the force of the pitch cylinder 21 contracting, the pressure on the bottom side of the angle cylinders 15 and 15 'reaches the port relief set pressure, and the angle force by the angle cylinder force balances the load F on the head side. There is pressure.

As a result, the oil escapes from the left port relief valve 41, and the stroke ratio of the left and right angle cylinders 15 and 15 'is Becomes Further, the movement due to the inclination of the pitch axis S is the same as the case.

In the case of right full angle state, no angle load, with, front pitch, as shown in FIG. 9, since the left angle cylinder 15 extends and the stroke end, the right angle cylinder 15 'may extend.

To do so, oil escapes from the left port relief valve 41,
Oil needs to be sucked in through the suction valve 45 on the right.

After all, assuming the pitch axis S in Fig. 10, the angle cylinder
It suffices if the pitch cylinder 21 overcomes the force of 15,15 'head side port relief.

The blade 6 moves like a left tilt and a left angle. The above operation is reversed at the left full angle.

In the case of right full-angle state, no angle load, with, and rear pitch, as shown in FIG. 11, the right angle cylinder 15 'contracts and the left angle cylinder 15 contracts because it is the stroke end.

To do so, oil escapes from the left port relief valve 41,
Oil needs to be sucked in through the suction valve 45 on the right.

After all, assuming the pitch axis S in Fig. 12, the angle cylinder
It suffices if the pitch cylinder 21 overcomes the force of the port relief of the bottom side of 15,15 '.

The blade 6 moves like a left tilt and a left angle. The above operation is reversed at the left full angle.

The operation of the angle cylinders 15 and 15 ′ is performed by switching the left and right switching positions of the angle switching valve 30, and the operation of the lift cylinders 12 and 12 ′ is performed on the lift switching valve 32.
This is done by switching the lower and floating switching positions.

Further, the operation of the tilt cylinder 21 is performed by switching the switching positions A and B of the tilt (pitch) switching valve 31 at the same time as the solenoid on-off valve 5
4 is opened and the solenoid on-off valve 55 is closed.

Further, in the control of each operation, as shown in FIG. 13, the left and right angle operations are performed by the angle control lever 80, and lift up, down, float operation, tilt left,
The control lever 90 is used for the right and front / rear pitch movements. The operation before and after the pitch is performed while pressing the button 91.

[Effect of device]

As described in detail above, the soil discharging device of the bulldozer according to the present invention includes a port relief valve and a parallel circuit connecting the head side of the left (right) angle cylinder and the bottom side of the right (left) angle cylinder, respectively. An angle cylinder circuit provided with a suction valve, a tilt cylinder circuit for connecting a tilt cylinder to a tilt (pitch) switching valve and a pitch cylinder circuit for connecting a pitch cylinder to a tilt (pitch) switching valve are arranged in parallel, and a tilt cylinder circuit and And a circuit configuration in which an electromagnetic on-off valve is provided in each of the pitch cylinder circuits.

Therefore, a pitch cylinder circuit dedicated to the pitch action of the blade is provided, and the expansion / contraction movement of the pitch cylinder by this pitch cylinder circuit is also used as a tilt (pitch) switching valve. The release of the restraint can be performed with the port relief valve and the suction valve.

Therefore, the angle and pitch of the blade can be easily obtained, and the switching operation structure can be simplified.

[Brief description of drawings]

1 is a perspective view of an embodiment of the present invention, FIG. 2 is a view from the direction of FIG. 1 II, FIG. 3 is a hydraulic circuit diagram, and FIGS.
FIG. 13 is an explanatory diagram showing the relationship between the pitch action and the operation of the angle cylinder, and FIG. 13 is an explanatory diagram of the control lever. 15,15 'is an angle cylinder, 21 is a pitch cylinder, 41,
44 is a port relief valve, 42 and 45 are suction valves, and 54 and 55 are solenoid valves.

Claims (1)

[Scope of utility model registration request] 1. An angle cylinder circuit in which a port relief valve and a suction valve are respectively provided in a parallel circuit that connects the head side of the left (right) angle cylinder and the bottom side of the right (left) angle cylinder, and a tilt ( A circuit configuration in which a tilt cylinder circuit for connecting a tilt cylinder to the (pitch) switching valve and a pitch cylinder circuit for connecting a pitch cylinder to the tilt (pitch) switching valve are arranged in parallel, and an electrode opening / closing valve is provided in each of the tilt cylinder circuit and the pitch cylinder circuit. An earth removing device for a bulldozer, which is provided with.