JPH0633011Y2 - Vibration suppressor and shock absorber for motor grader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a vibration suppressor and shock absorber for a motor grader.

[Conventional technology]

(1) The conventional motor grader does not have suspension as shown in FIG. 8, and it is impossible to suppress vibrations such as body bouncing and pitching during traveling.

(2) As shown in FIG. 9, the hydraulic circuit of the conventional working machine 2 includes the blade lift cylinder 5, the working machine pumps 10-1 and 10-2, the tanks 11-1 and 11-2, and the blade operating valve 8-. It was only connected via 1, 8-2.

[Problems to be solved by the device]

Since the conventional motor grader as described above has no suspension, and the front wheels 3 and the rear wheels 4 are hollow rubber tires, vibrations such as body bouncing and body pitching occur near a specific vehicle speed during traveling, which hinders driving. In some cases.

It is an object of the present invention to provide a device for suppressing the above-mentioned vibration and at the same time preventing the working machine from being pushed up from the road surface.

[Means for Solving the Problems]

(1) Considering the vehicle body 1 as a main vibration system, a sub vibration system having a vibration suppressing effect of the main vibration system is provided between the front wheels and the rear wheels.

(2) In order to use the hydraulic circuit of the work machine as a sub-vibration system,
An accumulator is connected to the rod side and head side hydraulic circuits of the blade lift cylinder that holds the working machine via a switching valve.

[Action]

When the rod side circuit of the blade lift cylinder and the accumulator communicate with each other, a sub-vibration system is configured to suppress vehicle vibration during traveling.

When the head side circuit of the blade lift cylinder and the accumulator communicate with each other, the bumping impact of the working machine due to the unevenness of the road surface during work is buffered.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention, in which a blade lift operation valve 8-1 and 8-2 are connected to a blade lift cylinder 5 by a hydraulic circuit so as to extend and retract. The lift cylinder 5 moves the work machine 2 up and down.

An accumulator 6 is connected to the rod side hydraulic circuit of the blade lift cylinder 5 through a switching valve 9-1 and a variable throttle 7-1, and a switching valve 9-2 and a variable throttle 7-2 are connected to the head side hydraulic circuit.
Similarly, the accumulator 6 is connected via.
The work machine 2 is connected to the vehicle body 1 by a blade lift cylinder 5 so as to be vertically movable.

Incidentally, 10-1 and 10-2 are work implement pumps, and 11, 11-1 and 11-2 are tanks.

(1) Traveling When traveling, as shown in FIG. 7, the blade lift operating valves 8-1 and 8-2 are in a neutral state with the work implement 2 lifted above the ground. At this time, when the switching valve 9-1 is opened and the switching valve 9-2 is closed, the rod side hydraulic circuit of the blade lift cylinder 5 has a variable throttle.
It is connected to the accumulator 6 via 7-1, and the working machine 2 is held so as to be vertically movable. At this time, the accumulator 6 exerts a spring effect and the variable diaphragm 7-1 exerts a damping effect, and the vibration system is as shown in FIG. At this time, M becomes the main vibration system by the mass of the vehicle body 1, and K and C become the spring constant and damping coefficient of the front and rear wheel tires 3, 4. Further, m is the mass of the working machine 2 and serves as a secondary vibration system, k is a spring constant determined by the accumulator 6, and c is a damping coefficient determined by the variable aperture 7-1. By setting these numerical values to the optimum values peculiar to the vehicle, the sub vibration system vibrates during traveling, and the vibration of the main vibration system can be suppressed.

(2) During normal operation Switch valves 9-1 and 9-2 are closed, and blade lift operation valves 8-1 and 8
-Working machine 2 can be moved up and down by operating -2.

(3) When the shock absorber is operating When the work implement 2 is grounded as shown in Fig. 6, the switching valve
By closing 9-1 and opening the switching valve 9-2, the head side hydraulic circuit of the blade lift cylinder 5 is connected to the accumulator 6 via the variable throttle 7-2. As a result, a pressing force is applied to the working machine 2, and when the working machine 2 collides with the road surface convex portion as shown in FIG. 5 during work in this state, the air chamber of the accumulator 6 contracts and the working machine 2 moves to the fifth position. Escape as shown by the arrow, and shock can be buffered.

[Second Embodiment] FIG. 3 shows a second embodiment of the present invention. The blade lift operation valves 8-1 and 8-2 are connected by a hydraulic circuit so that the blade lift cylinder 5 can be expanded and contracted, and the blade lift cylinder 5 moves the working machine 2 up and down. An accumulator 6-1 is connected to the rod side hydraulic circuit of the blade lift cylinder 5 via a switching valve 9-1 and a variable throttle 7-1. In the head side hydraulic circuit of the blade lift cylinder 5, a switching valve 9-2,
An accumulator 6-2 is connected via a variable diaphragm 7-2. The work machine 2 is connected to the vehicle body 1 by a blade lift cylinder 5 so as to be vertically movable.

(1) Traveling When running, the blade lift operating valves 8-1 and 8-2 are neutral with the work implement 2 lifted above the ground as shown in FIG.
At this time, when the switching valves 9-1 and 9-2 are opened, the working machine 2 is held by the rod side accumulator 6-2 and the head side accumulator 6-1 of the blade lift cylinder 5 so as to be able to move up and down. The vibration system at this time is shown in FIG. 4, where M is the main vibration system with the mass of the vehicle body 1, K and C are the front and rear tires, 3,
The spring constant and damping coefficient are 4. Further, m is the mass of the working machine 2 and serves as a secondary vibration system, k-1 is the spring constant determined by the accumulator 6-1, k-2 is the spring constant determined by the accumulator 6-2, and c-1 is the variable diaphragm 7-1. The damping coefficient determined by c-2 is the damping coefficient determined by the variable aperture 7-2. By setting these numerical values to the optimum values peculiar to the vehicle, the sub vibration system vibrates during traveling, and the vibration of the main vibration system can be suppressed.

(2) During normal operation Switch valves 9-1 and 9-2 are closed, and blade lift operation valves 8-1 and 8
-Working machine 2 can be moved up and down by operating -2.

(3) When the shock absorber is operating When the work implement 2 is grounded as shown in Fig. 6, the switching valve
Open 9-1 and 9-2. At this time, the blade lift cylinder 5
A pressing force is applied to the work implement 2 by the accumulator 6-1 on the head side. When the work implement 2 collides with the road surface convex portion as shown in Fig. 5 during work in this state, the air chamber of the accumulator 6-1 contracts, the work implement 2 escapes as shown by the arrow in Fig. 5, and the shock is buffered. it can.

[Effect of device]

The vibration suppressor and shock absorber of the motor grader according to the present invention supports a working machine between a front wheel and a rear wheel of a vehicle body by a pair of blade lift cylinders so as to be able to move up and down, and in a motor grader without a suspension system, A rod side switching valve and a head side switching valve connected to the rod side hydraulic circuit and the head side hydraulic circuit of both blade lift cylinders, and the rod side hydraulic circuit or the head side hydraulic circuit of each blade lift cylinder via these switching valves. The following effects can be obtained by including the accumulators communicating with each other and the variable throttles arranged in each hydraulic circuit between the accumulators and the switching valve.

(1) The vibration of the main vibration system consisting of the vehicle body, the front wheels, and the rear wheels is suppressed by the vibration of the auxiliary vibration system consisting of the working machine, the rod side hydraulic circuit of the blade lift cylinder, and the accumulator, so that the vehicle body when the grader runs Vibration can be suppressed.

(2) By connecting the accumulator to the head side hydraulic circuit of the blade lift cylinder, it is possible to buffer the shock received from the convex portion of the road surface during work.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of the first embodiment of the present invention, FIG. 2 is a vibration system diagram of the first embodiment, FIG. 3 is a hydraulic circuit diagram of the second embodiment of the present invention, and FIG. FIG. 5 is a vibration system diagram of an embodiment, FIG. 5 is a shock absorbing operating state diagram of the present invention, FIG. 6 is a working state diagram of the present invention, and FIG. 7 is an operating state diagram of a traveling vibration suppressing device of the present invention,
FIG. 8 is an overall schematic view of a motor grader, and FIG. 9 is a hydraulic circuit diagram of a working machine in a conventional motor grader. 1 ... Body, 2 ... Working machine 3 ... Front wheel, 4 ... Rear wheel 5 ... Blade lift cylinder 6 ... Akylumulator, 7-1, 7-2 ... Variable throttle 8-1, 8-2 ... … Grade operation valve 9-1, 9-2 …… Switching valve

Claims (2)

[Scope of utility model registration request] 1. In a motor grader having a pair of blade lift cylinders for supporting a working machine between a front wheel and a rear wheel of the vehicle body so as to be able to move up and down, a rod side hydraulic pressure of both blade lift cylinders. Circuit and a head side hydraulic circuit, a rod side switching valve and a head side switching valve, and a pair of accumulators communicating with the rod side hydraulic circuit or the head side hydraulic circuit of each blade lift cylinder via these switching valves, A vibration suppressing and shock absorbing device for a motor grader, which comprises these accumulators and variable throttles arranged in each hydraulic circuit between the switching valves. 2. A motor grader having a pair of blade lift cylinders that support a working machine provided between front and rear wheels of the vehicle body so as to be able to move up and down. A rod side switching valve and a head side switching valve connected to the rod side hydraulic circuit and the head side hydraulic circuit, and two pairs that communicate with the rod side hydraulic circuit and the head side hydraulic circuit of each blade lift cylinder via these switching valves, respectively. Of Aki Yumulator
A vibration suppressing and shock absorbing device for a motor grader, which comprises these accumulators and variable throttles arranged in each hydraulic circuit between the switching valves.