JPS5853445Y2 - Circuit structure of backhoe and dozer work vehicle - Google Patents

Description

[Detailed Description of the Invention] The present invention is configured such that the first and second fluid pressure motors for the left and right traveling devices can be driven by separate pumps, and the control pulp of the first motor and the cylinder for driving the arm of the backhoe are connected to each other. The control valves are configured in a multiple valve type in which the control valves are connected in parallel, and the control pulp for the second motor, the control valve for merging with the arm driving cylinder, and the control pulp for driving the dozer are configured in the multiple valve type. The present invention relates to the circuit structure of the constructed backhoe/dozer work vehicle.

According to the above circuit structure, by making each control pulp a multiple valve type, the piping system for piping and pulp arrangement can be simplified, and the entire piping system can be made compact.
Further, by providing an arm merging circuit in the fluid pressure system of the pump for the second traveling motor, the workability of the arm can be improved.

By the way, in order to be able to perform dozer work while suppressing the skew of the aircraft, it is important to connect the control pulp for the second travel motor and the dozer cylinder in series. Due to the valve-type pulp structure, it is impossible to connect the control pulp for arm merging in parallel to the series-connected pulp, resulting in a series-connected state. When escaping from a wetland by raking the arm while driving both motors, even if one of the first traveling motors connected in parallel can maintain the driving state, the other second motor may When the working back pressure of the arm builds up, the drive stops, and not only is it possible to run on one leg, making it impossible to escape from the wetland properly, but the pressure fluid is relieved, resulting in an increase in the temperature of the pressure fluid and a loss of engine driving power. On the other hand, if we adopt a circuit structure that allows arm work while in a running state, the machine body will skew during dozer work.

That is, in order to take advantage of the advantages of the multiple valve type valve structure, it is impossible to perform either dozer work without skew or arm work while traveling.

The present invention makes it possible to perform both of the above-mentioned tasks while taking the form of a multiple valve type by simply improving the valve arrangement, and further improves the versatility of the work vehicle by making effective use of the circuit structure resulting from this improvement. Its characteristic configuration is that, in the circuit structure of the backhoe/dozer work vehicle mentioned above, the dozer control valve and the second motor control pulp are connected in series, and both control valves are connected in series. On the other hand, the merging control valve is connected in series through a supply flow path on the downstream side,
Furthermore, a switching valve that can be freely switched between a state in which the flow path is shut off and the supply fluid from the flow path is returned to the tank side from the discharge path and a state in which the flow path is opened is incorporated in the supply flow path, and The present invention is characterized in that the discharge passage is provided with a flow passage connector that can switch and connect the discharge passage to the actuator side of the attachment.

The effects of the characteristic configuration of the present invention are as follows.

That is, by connecting the second motor valve and the dozer valve in series, it is possible to perform dozer work while suppressing skew movement, and by cutting off the arm merging circuit with the switching valve, it is possible to escape from the wetland. It is possible to perform arm work while traveling without having to stop with one leg, and by simply adding the above-mentioned switching valve and incorporating it into a multiple valve type valve group, While taking advantage of the advantages of the multiple valve type, we were able to further improve the workability mentioned above.

Moreover, by effectively utilizing the circuit structure that adds the switching pulp and connecting the discharge path of this switching pulp to the actuator of an attachment such as a breaker, 1. The switching valve can also be used, increasing the versatility of the work. was able to improve.

Next, embodiments of the present invention will be described in detail with reference to illustrative drawings.

A swivel base 3 is attached to a machine base 2 provided with left and right crawler traveling devices 1, 1, a backhoe A, a control section 5, and an engine equipment 6 are installed on this swivel base 3, and a dozer 4 is installed on the travel machine base 2. The work vehicle is made up of:

The backhoe A is provided with a bracket 7 that can swing left and right with respect to the swivel base 3, a fluid pressure cylinder 8 is provided between the bracket 7 and the swivel base 3, and an arm 9 at the tip.
A boom 10 equipped with a boom 10 is connected to the bracket 7, a packet 11 is connected to the tip of the arm 9, and a fluid pressure cylinder 12 is interposed between each bending member of the horizontal shaft member 9. has been done.

The cylinders 8, 12, .
Two constant discharge type fluid pressure pumps P□.

It is controlled by a hydraulic system shown in FIG. 2' based on P2.

This fluid pressure system has one first pump P□ connected to a first pump for traveling.
Motor M0, swing motor M and arm cylinder 12
And the husband for joining to boom cylinder 12! Parallel section type control valve ■1, ■2, V3
, ■ 4 are connected in parallel, and they are arranged adjacent to each other to form a multiple valve type valve group B.
Pump P2 is connected in series with control valves ■5 and ■6 of the opposite series section type to the dozer cylinder 13 and the second traveling motor M2, and on the lower side with respect to both control valves ■5 and ■6, A series section type control valve v9 for merging with respect to the arm driving cylinder 12 is connected in series through a supply flow path a, and further, in the middle of the supply flow path a from both control valves V5yV6 to the merging control valve 9, A parallel section type control valve V7tV8 for the packet 11 and the boom 9 and a switching pulp V for switching the supply direction of the supply fluid are installed in parallel with each other, and the control valves v5, v6. ■
7. ■8. v9 and the switching valve ■ are arranged adjacent to each other to form a multiple valve type valve group C, and the arm valve v3 and the arm merging valve ■9, and the boom valve v3 and the boom merging valve v4 are arranged respectively. In addition to interlocking the pumps P1 and P2, a valve ■□0 is provided to switch between supplying the pressure fluid of both pumps P1 and P2 separately to the motors M1 and M2, and combining and supplying the fluid directly to the motors M1 and M2. It is possible to control the traveling speed in two stages, high and low, by switching the switch, and the pool 9 can be controlled by the linked operation of the merging valve v4.
Alternatively, the merging work of the arm 10 can be controlled, and when the arm work is performed while traveling, the switching valve V
By completely releasing the flow from the second pump P2 to the arm cylinder 12, it is possible to control work such as escaping from a wetland, and it is also possible to perform dozer work while traveling in a state where oblique travel is suppressed. ing.

Discharge paths (excluding the supply flow path a) to the merging control valve (■9) constituted by the center bypass path (a) of the switching valve (V) are valves (■□3) for preventing fluid backflow to the valve (■). ■It is connected on the downstream side of 13, and its confluence route d
are connected to the tank T, and the valves ① and 3. v□3
Flow path connectors e, e are provided on the upper side of the packet 11, and the discharge paths s, c are connected to flow path connectors f, f of an actuator 14 of an attachment such as a breaker installed in place of the packet 11. With the switching valve (1) being used also as an operation valve and in a state where the arms are not merging, attachment work other than the original work function can be performed.

The connecting devices e, e, f, and f can be modified in various ways, such as replacing them with flow path switching valves as shown in FIG. It is also possible to incorporate it into one of the valve groups B and C of the type to effectively take advantage of the advantages of the multiple valve type.

In the figure, ■□, . . . are brake valves for each motor M, M□ 2M2, and v12 is a valve that switches the flow path for the swing motor M to the work equipment swing cylinder 8, which has the same working form. By sharing the swing valve 2, the backhoe A is configured to swing with the same feeling of operation.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the circuit structure of the backhoe/dozer work vehicle according to the present invention, in which FIG. 1 is an overall side view of the work vehicle, FIG. 2 is a fluid pressure system diagram, and FIG. 3 is a diagram of the connection device. It is a partial fluid pressure system diagram of two aspects. 12...Arm drive cylinder, Pl, P2
...Pump, b, c...Discharge path, 14
...actuator, ■1, v5, ■6
, ■9... Control valve, f...
・Connection tool, Ml tM2...Fluid pressure motor,
■・・・・・・Switching valve.

Claims (1)

[Scope of utility model registration request] The first and second fluid pressure motors M1 and M2 for the left and right traveling devices are configured to be driven by separate pumps P1tP2, and
The control pulp V1 of the motor M1 and the control pulp ■3 of the cylinder 12 for driving the arm of the backhoe A are connected in parallel to form a multiple valve type, and the control pulp ■6 of the second motor M2 and the control pulp ■3 for driving the arm are connected in parallel. Confluence control valve for cylinder 12■
This is a circuit structure of a backhoe/dozer work vehicle in which a dozer drive mechanism control valve V5 and a dozer drive mechanism control pulp V5 are configured in a multiple valve type, wherein the dozer control valve V5 and the second motor control pulp V6 are In addition to connecting these control valves V5tV6 in series, the merging control pulp ■9 is connected in series with the supply flow path a on the downstream side of both control valves V5tV6, and furthermore, the flow path is blocked and the supply from that flow path is A switching pulp (2) that can freely switch between a state in which the fluid is returned to the tank side from the discharge path (c) and a state in which the flow path is opened is installed in the supply flow path (a), and the discharge path (c) is connected to the attachment. A circuit structure of a dozer and dozer work vehicle, characterized in that a flow path connector e that can be switched and connected to an actuator 14 side is provided on the discharge path and c.