JPH0128131Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scraper bowl suspension system for a motor scraper.

The front wheels of the motor scraper are fixed to the tractor frame, the rear wheels to the scraper frame, and the tractor frame and the scraper frame are connected by a king pin. Road surface irregularities are transmitted to the tractor frame via the front and rear wheels.

Therefore, in the vibration system formed by the tractor frame and the front and rear wheels, each of the front and rear wheels has a natural vibration period. Since the period of acceleration of the front and rear wheels changes depending on the distance between the unevenness of the road surface and the vehicle speed, resonance may occur in some cases, and the amplitude of the front or rear of the vehicle or the other party becomes extremely large. Bouncing occurs when the front and rear phases match, and pitching occurs when the phases shift.

This pitching and bouncing become a major hindrance to motor scraper work, resulting in severe operator fatigue. For this reason, a suspension mechanism is installed between the front axle and the tractor frame to absorb vibrations and improve riding comfort, but the vibrations transmitted from the rear axle to the scraper frame are transmitted directly to the tractor frame via the king pin. Put it away.

FIG. 1 shows a conventional scraper bowl suspension system.

In FIG. 1, pressure oil discharged from a pump 1 is sent to a bowl control hydraulic valve 2', and this bowl control hydraulic valve 2' is operated directly or via air (hydraulic pressure, etc.) by an operator's operation. By operating this bowl control hydraulic valve 2', pressure oil is sent to the head side or rod side of the bowl cylinder 3' to move the bowl up and down. The bowl control hydraulic valve 2' is normally in a holding state, and the pressure oil sent to the bowl cylinder 3' is transferred to the bowl control hydraulic valve 2'.
Since the vibration of the scraper frame is contained in the frame, the vibration of the scraper frame is directly transmitted to the tractor frame.

The present invention was developed in view of the above circumstances, and its purpose is to absorb the vibration of the scraper frame when the bowl moves up and down due to the unevenness of the road surface and reaches an arbitrary position. The aim is to eliminate vibration transmission and improve riding comfort.

Hereinafter, the present invention will be explained with reference to FIGS. 2 and 3.

In the drawing, 9 is a yoke, and a bowl 11 is held by this yoke 9 via a yoke arm 26 so as to be movable up and down. Yoke 9 has bowl cylinder 3
One end of the bowl cylinder 3 is connected, and the other end of the bowl cylinder 3 is connected to the upper front end of the bowl 11.

A lever 8 is rotatably provided at the fulcrum A of the yoke arm 26 in the yoke 9, and an intermediate lever portion 8a of the lever 8 is connected to the bowl 1 via a rod 10.
It is swingably connected to the front end of 1.

Reference numeral 2 in the drawing indicates an operating valve, and a pump port 2a of the operating valve 2 is connected to the discharge side of the pump 1 via a first pipe line 14, and a relief valve 15 is provided in this first pipe line 14. . Further, the tank port 2b communicates with the tank 27.

Ports 2c and 2d of the operating valve 2 are connected to ports 5c and 5d of the switching valve 5 via second and third pipes 16 and 17.
It is connected to. The port 5a of the switching valve 5 is connected to the rod side of the bowl cylinder 3 via the fourth pipe 18, and the port 5b of the switching valve 5 is connected to the fifth pipe 1.
9 is connected to the head side of the bowl cylinder 3, and a switch 4 is further provided in the electrical circuit of the solenoid 28 of the switching valve 5, and these constitute a bowl control hydraulic circuit 30.

7 in the drawing is a suspension valve, and pump ports 7d and 7e of this suspension valve 7 are the sixth
It is connected to the discharge side of the pump 6 via a conduit 22, and a relief valve 23 is provided in this sixth conduit 22.

The port 7a of the suspension valve 7 is connected to the seventh pipe line 2.
0 to the port 5e of the switching valve 5, and the port 7b of the suspension valve 7 is connected to the tank 2.
It leads to 7.

The port 7c of the suspension valve 7 is connected to the eighth pipe line 3.
1 to the accumulator 12, and a variable throttle 13 is provided in the eighth pipe line 31. The port 5f of the switching valve 5 is connected to the tank 2 via the ninth pipe line 21.
7, and this ninth conduit 21 is provided with the variable throttle 13. Spool 2 of variable aperture 13
4 is swingably connected to the upper lever 8b of the lever 8, and the spool 25 of the suspension valve 7 is swingably connected to the lower lever part 8c of the lever 8. circuit 33
It consists of

Next, the operation will be explained.

During normal operation, the switch 4 is OFF and the position is located on the port side of the switching valve 5, and the operation valve 2 can supply and discharge the oil discharged from the pump 1 to the bowl cylinder 3, allowing normal bowl control. A hydraulic circuit 30 is formed.

When Traveling When the excavation work or the like is finished, the bowl 11 is in a lowered state. When the switch 4 is turned on, the changeover valve 5 is operated, position RO is located on the port side, and the seventh and ninth pipes 20 and 21 communicate with the bowl cylinder 3. That is, the bowl control hydraulic circuit 30 is closed and the suspension circuit 33 is opened.

Since the bowl 11 is currently in a lowered position, the raised position is located on the port side of the suspension valve 7, and the pressure oil from the pump 6 passes through the suspension valve 7 and the switching valve 5 to the rod of the bowl cylinder 3. At the same time as it is sent to the side, it is also sent to the accumulator 12 and the bowl 11 is raised.

If the rod 10 is adjusted so that the holding position is located on the port side of the suspension valve 7 when the bowl 11 is located at an arbitrary position, for example at the center of the stroke of the bowl cylinder 3, the bowl 11 can be
When the pressure oil reaches a certain arbitrary position, the pressure oil from the pump 6 is returned to the tank 27 through the suspension valve 7, and the bowl cylinder 3 and the accumulator 12 are
The pressure oil between them is connected and trapped.

While driving, when the bowl 11 moves up and down due to unevenness on the road surface, the suspension valve 7 operates via the rod 10 connected to the bowl 11 and the lever 8, and pressurized oil is supplied to the bowl cylinder so that the bowl 11 is always at a desired position. Send it to 3.

The variable throttle 13 is completely throttled when the bowl cylinder 3 is extended too much due to sudden load fluctuations and the bowl 11 is lowered to a certain position to prevent the cutting edge of the bowl 11 from touching the road surface.
2 is cut to prevent the bowl 11 from lowering any further.

Further, the variable throttle 13 prevents the bowl cylinder 3 from contracting too much due to sudden load fluctuations, and the piston 3-a colliding with the cylinder bottom.

As described in detail above, the present invention includes a bowl control hydraulic circuit 30 that supplies and discharges oil discharged from the pump 1 to and from the bowl cylinder 3 by switching the operation valve 2 to operate the vertical movement of the bowl 11, and a suspension hydraulic circuit 30. an accumulator 12 provided in the circuit 33;
A suspension valve 7 provided in the suspension hydraulic circuit 33 to supply and discharge oil discharged from the pump 6 to the bowl cylinder 3 and to confine pressure oil between the accumulator 12 and the bowl cylinder 3 at a neutral position, and a bowl control hydraulic circuit. A switching valve 5 is provided on the yoke 9 to switch the supply of oil to the bowl cylinder 3 to either the bowl control hydraulic circuit 30 or the suspension hydraulic circuit 33, and the suspension valve 7 is provided on the yoke 9 and rotates to switch the supply of oil to the bowl cylinder 3. A scraper bowl suspension comprising: a lever 8 for switching the position; and a rod 10 for connecting the lever 8 and the bowl 11 and setting the suspension valve 7 to a holding position when the bowl 11 is located. It is a device.

Therefore, when the bowl 11 comes to an arbitrary position, the suspension valve 7 becomes the holding position, and the pressure oil between the accumulator 12 and the bowl cylinder 3 is trapped, and the bowl 11 is trapped due to the unevenness of the road surface.
When the scraper frame reaches an arbitrary position in the vertical direction, the above occurs, so the scraper frame vibration is absorbed, and the vibration of the truck frame is not transmitted, thereby improving riding comfort.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a conventional scraper bowl suspension device, FIG. 2 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIG. 3 is a characteristic diagram of the opening area of a variable diaphragm. 5 is a switching valve, 7 is a suspension valve, 8 is a lever, 10 is a rod, and 12 is an accumulator.

Claims (1)

[Scope of utility model registration request] a bowl control hydraulic circuit 30 that supplies and discharges oil discharged from the pump 1 to and from the bowl cylinder 3 by switching the operation valve 2 to operate the vertical movement of the bowl 11;
An accumulator 12 provided in the suspension hydraulic circuit 33 and a bowl cylinder 3 provided in the suspension hydraulic circuit 33 for discharging oil from the pump 6.
a suspension valve 7 that confines pressure oil between the accumulator 12 and the bowl cylinder 3 at a neutral position, and a bowl control hydraulic circuit 30.
A switching valve 5 is provided on the yoke 9 to switch oil supply to the bowl cylinder 3 to either the bowl control hydraulic circuit 30 or the suspension circuit 33, and a switching valve 5 is provided on the yoke 9 to change the position of the suspension valve 7 by rotation. This scraper bowl suspension device is characterized by comprising: a lever 8 for switching the scraper bowl; and a rod 10 for connecting the lever 8 and the bowl 11 and setting the suspension valve 7 to a holding position when the bowl 11 is located.