JP2578045Y2 - Hydraulic control device for hydraulic working machine mounted on vehicle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for a hydraulic working machine mounted on a vehicle, such as a crane truck or an aerial work vehicle.

[0002]

2. Description of the Related Art Some vehicle-mounted hydraulic working machines drive a hydraulic pump, which is a driving hydraulic source of the working machine, with an engine for running the vehicle. Two hydraulic pumps are used as driving hydraulic sources of the working machine. Some of these are driven by a single engine.

[0003] In this type of vehicle-mounted hydraulic working machine, the rotational speed of the engine is conventionally set to a high speed from the viewpoint of ensuring an engine output sufficient to simultaneously drive two hydraulic pumps.

[0004]

In such a prior art, when the oil discharged from both hydraulic pumps is used to drive the working machine, the rotational speed is set to a higher value as described above. The output of the engine is utilized effectively as a whole.

However, when the working machine is driven only by the oil discharged from one hydraulic pump (referred to as first hydraulic pump), the oil discharged from the other hydraulic pump (referred to as second hydraulic pump) is returned to the oil tank. In this case, the output of the engine at the increased rotation speed in order to enable the second hydraulic pump to be driven also has a correspondingly large loss.

[0006] In addition, when the rotational speed of the engine is set to be high, the noise is correspondingly large, and the fuel economy is uneconomical.

The present invention has been made based on such a background, and reduces the loss of the output of an engine that drives a hydraulic pump for this type of vehicle-mounted hydraulic working machine, thereby reducing the noise generated by the engine. It is intended to reduce fuel consumption and improve fuel efficiency.

[0008]

In order to achieve this object, a first aspect of the present invention provides a hydraulic control system for a vehicle-mounted hydraulic working machine of this type, wherein at least a control valve is provided for a second hydraulic pump. A speed increasing section for increasing the rotation speed of the vehicle running engine is provided before the discharge oil is supplied to the discharge oil passage of the first hydraulic pump.

[0009]

According to the first aspect of the present invention, when the discharge oil from both the first and second hydraulic pumps is to be supplied to the hydraulic actuator of the work machine, the supply of the discharge oil from the second hydraulic pump is performed. Prior to the above, since the speed increase section of the rotation speed of the engine for driving the first and second hydraulic pumps is provided, when the work machine is driven only by the discharge oil of the first hydraulic pump, The rotation speed of the engine can be set lower than in the past, and when the working machine is driven by the discharge oil of both the first hydraulic pump and the second hydraulic pump, it is sufficient to go through the speed increasing section. Engine output can be secured.

Therefore, it is possible to reduce the loss of the output of the engine that drives the hydraulic pump for this type of vehicle-mounted hydraulic working machine, thereby reducing the noise caused by the engine and improving the fuel efficiency.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings.

In this embodiment, the vehicle-mounted hydraulic working machine is a crane truck 1 equipped with a hydraulic crane.

First, an outline of the crane truck 1 will be described with reference to FIG.

The crane truck 1 has a self-propelled vehicle 2 and a hydraulic crane 4 mounted on a vehicle body 3 of the vehicle 2.

The crane 4 has a swivel 5 installed on the vehicle body 3 so as to be able to turn horizontally, a telescopic boom 6 mounted on the swivel 5 so as to be able to move up and down, and a winch device 7 for lifting. .

Various operations such as turning the swivel table 5, raising and lowering the telescopic boom 6 and raising and lowering the winch device 7 are performed by various hydraulic actuators.

More specifically, the turning operation of the turning table 5 is performed by a turning hydraulic motor (not shown), the raising and lowering operation of the telescopic boom 6 is performed by the raising and lowering hydraulic cylinder 11, and the telescopic operation of the telescopic boom 6 is performed by the expanding and contracting hydraulic cylinder. In the cylinder 12, the operation of raising and lowering the winch device 7 is performed by a winch hydraulic motor (not shown).

A first and a second hydraulic pump 22, which are driven by a vehicle traveling engine (hereinafter simply referred to as an engine) 21 via a hydraulic control device 20 shown in FIG. The discharge oil from 23 is supplied, and the required operation of the crane 4 can be performed.

FIG. 1 shows the telescopic hydraulic cylinder 12 of the telescopic boom 6 as a hydraulic actuator, and the other hydraulic actuators have the same configuration.

Hereinafter, the hydraulic control device 20 will be described with reference to FIG. 1 as an example in which the telescopic hydraulic cylinder 12 is driven.

The output shaft of the engine 21 is mechanically connected to pump shafts of first and second hydraulic pumps 22 and 23, and the first and second hydraulic pumps 22 are rotated as the engine 21 rotates. , 23 are rotatably driven to discharge the oil sucked from the oil tank 27.

A first discharge oil passage 24 is connected to the discharge port of the first hydraulic pump 22.
4 is connected to the main valve 25.

The main valve 25 is a valve device for switching the pressure oil supplied from the first discharge oil passage 24 to one of the hydraulic actuators and having a variable throttle function. This corresponds to the hydraulic switching valve referred to in FIG.

The switching of the main valve 25 and the setting of the aperture are performed under the control of a computer 52 as will be described later.

FIG. 1 shows a state in which the main valve 25 is switched to extend and extend the telescopic hydraulic cylinder 12 as a hydraulic actuator comprising a double-acting hydraulic cylinder.

That is, in the telescopic hydraulic cylinder 12, an oil passage 26a is provided in the cylinder chamber 12a behind the piston.
At the same time, an oil passage 26b is connected to the cylinder chamber 12b on the piston rod side from the main valve 25, respectively.

Inside the main valve 25, a discharge oil is supplied to the oil passage 26a in communication with the first discharge oil passage 24, and the oil passage 26b is connected to a drain oil passage 29. Thus, the oil discharged from the cylinder chamber 12b on the piston rod side is returned to the oil tank 27.

When the expansion / contraction hydraulic cylinder 12 is driven to contract, the discharge oil is supplied to the cylinder chamber 12b and the oil discharged from the cylinder chamber 12a is returned to the oil tank 27 in the same manner as described above.

A second discharge oil passage 31 is connected to a discharge port of the second hydraulic pump 23.
The other end of 1 is connected to a merge switching valve 32.

The junction switching valve 32 is a three-port two-position switching valve having a variable throttle function, and corresponds to the control valve according to the present invention.

On the outflow side of the merging switching valve 32, a merging oil passage 33 is connected to one port, and the other end of the merging oil passage 33 is connected to the first discharge oil upstream of the main valve 25. It is connected to the road 24.

A return oil passage 28 is connected to the other port on the outflow side of the merge switching valve 32 so that the oil discharged from the second hydraulic pump 23 can be returned to the oil tank 27.

The merging valve 32 is operated via a floating device 36 by an accelerator cylinder 37 composed of a solenoid valve based on a signal from a computer 52.

The specific structure of the floating device 36 in this embodiment is as shown in FIGS.

An oscillating link 38 whose lower end is pivotally connected to the vehicle body 3 is connected to the end of the output shaft 37a of the accelerator cylinder 37 shown in FIG. It is oscillatingly displaced accordingly.

On the upper part of the swing link 38, an accelerator wire cable 41 having the other end connected to an accelerator device (not shown) of the engine 21, and a merging switching valve 32 having the other end.
Wire cable 43 connected to the adjustment link 42
And are connected.

These wire cables 41 and 43 are formed by push-pull cables such as Bowden wires.

In the accelerator wire cable 41, a shaft 45 having long holes 44a and 44b is connected to an end of the inner cable on the side of the swing link 38,
The upper portion of the swing link 38 is inserted into the elongated hole 44a of the shaft 45, and the end of the guide pin 38a implanted in the swing link 38 is formed in the elongated hole 44b formed on both sides of the shaft 45. It is inserted inside.

A floating device 36 is formed by interposing a compression spring 46 between the flange 45a formed at the end of the shaft 45 and the upper part of the swing link 38.

The spring force of the compression spring 46 is set to be greater than the operating resistance of the accelerator wire cable 41. The compression spring 46 is held until the swing link 38 comes into contact with a stopper device 47 to be described later. 4
6 does not bend, the accelerator wire cable 41 is displaced in accordance with the swing displacement of the swing link 38, and the accelerator device of the engine 21 is operated to increase the rotation speed of the engine 21.

The position of the stopper device 47 is used to set the rotation speed of the engine 21 when both the first and second hydraulic pumps 22 and 23 are driven at the same time. Screw-type abutment 4
7b is capable of moving forward and backward in the axial direction of the shaft body 45 to adjust the set value.

On the other hand, the interlocking wire cable 43 is
The adjustment link 4 attached to the swing link 38 and the spool 32 a of the merge switching valve 32 by the inner wire.
The spool 32a is not displaced by the swing of the swing link 38 that performs idle-up with the rotation speed of the engine 21 slightly increased from the idling state as described later.

The interlocking wire cable 43 is
When the distal end of the shaft body 45 of the accelerator wire cable 41 is in contact with the contact fitting 47a of the stopper device 47, the spool 32a of the merge switching valve 32 does not fully open the oil passage. Cylinder 3
7, the output shaft 37a is projected, so that the swing link 38
Can move rightward in the elongated hole 44a of the shaft 45 attached to the end of the accelerator wire cable 41 against the spring force of the compression spring 46.

For this reason, the interlocking wire cable 43 is
The opening area of the oil passage of the junction switching valve 32 can be further increased without increasing the rotation speed of the engine 1.

The main valve 25 and the accelerator cylinder 37 of the hydraulic control device 20 configured as described above are
The electronic device is electrically operated based on the output of the computer 52 based on the input signal from the operation panel 51. In this embodiment, the signal from the operation panel 51 is transmitted wirelessly, and the signal is transmitted to the computer 52 side. Received by a receiver (not shown) installed in the
It is a wireless remote control type.

FIG. 5A shows a later-described speed control lever 54 (corresponding to the operation lever of the present invention).
The operation amount S by indicates the flow rate Q of the discharge oil passing through the main valve 25, reference numeral Q ₁ is due to the first hydraulic pump 22, Q ₂ is due to the second hydraulic pump 23.

FIG. 5B shows the rotational speed N of the engine 21 based on the operation amount S of the speed control lever 54.
And the change of the opening area U of the main valve 25 and the opening area V of the merging switching valve 32.

Hereinafter, the operation that occurs with the operation of the operation panel 51 will be described mainly with reference to FIGS. 5A and 5B.

First, of the operation selection switches on the operation panel 51, for example, the telescopic operation switch 53 of the telescopic boom 6 is operated. As a result, the accelerator cylinder 37 is operated, the output shaft 37a of the accelerator cylinder 37 is protruded to the right side in the figure by a minute length, and the rotation speed of the engine 21 is slightly increased from the idling rotation speed (for example, 430 rpm) (for example, 660r.
pm) is performed (Fig. 5
(Time point A) in (a) and (b).

The rotation speed of the engine 21 at this time is extremely lower than the conventional rotation speed (for example, 1500 rpm). Since some play is provided, the spool 32a of the merge switching valve 32 does not operate and remains closed.

Thereafter, the speed control lever 54 of the operation panel 51 is operated.

By this operation, the computer 52 instructs the main valve 25 corresponding to the operation selection switch to make the opening area correspond to the operation amount of the speed control lever 54, and the main valve 25 starts to open (FIG. 5). 5 (a), (B) time point B).

The increase in the amount of oil discharged through the main valve 25, which is started in such a manner, is changed to the state when the amount of oil discharged reaches the state corresponding to the operation amount S of the speed control lever 54 during the following process. It is maintained and the increase stops.

The opening of the main valve 25, which has been started in response to a command from the computer 52, gradually increases in the opening area.
2a (until time C in FIGS. 5A and 5B).

During this time, the oil discharged from the second hydraulic pump 23 is returned from the junction switching valve 32 to the oil tank 27 through the return oil passage 28, so that the load on the second hydraulic pump 23 is small and the rotational speed of the engine 21 is reduced. However, even if it is low as described above, there is no problem such as insufficient engine output.

In this way, when the opening of the main valve 25 is immediately before the opening of the main valve 25, the computer 52 issues an operation command to the accelerator cylinder 37, and the output shaft 37a of the accelerator cylinder 37 gradually moves the swing link 38 to the right side in the figure. Rocking displacement.

As a result, the rotation speed of the engine 21 starts to rise due to the pulling of the accelerator wire cable 41 and enters a speed-up section (time point C in FIGS. 5A and 5B).
Note that the speed-up section of the engine 21 in this embodiment is
It is between the time point C and a time point F described later.

Even in this state, the spool 3 of the merging switching valve 32 is moved by the play of the interlocking wire cable 43.
2a does not operate and remains closed.

Thereafter, until the opening of the main valve 25 is fully opened (at time D in FIGS. 5A and 5B), the rotation speed of the engine 21 and the opening area of the main valve 25 increase. As a result, the flow rate of the discharge oil increases.

After the opening of the main valve 25 is fully opened, the joining of the discharge oil from the second hydraulic pump 23 to the first discharge passage 24 by the joining switching valve 32 is started (FIG. 5).
Until the time point E) of (a) and (b), the engine 21
The rotation speed of the first hydraulic pump 2
The increase of the discharge oil amount from 2 also continues.

Then, during the speed-up section in which the rotation speed of the engine 21 continues to increase, the merger of the discharge oil from the second hydraulic pump 23 to the first discharge passage 24 by the merger switching valve 32 is gradually performed. The process starts (point E in FIGS. 5A and 5B).

In this embodiment, at this point E
The operation amount of the speed control lever 54 corresponding to the predetermined amount corresponds to the predetermined amount in the present invention.

After this time E, the telescopic hydraulic cylinder 12
The amount of discharge oil supplied to the first hydraulic pump 22 is increased by the increase in the rotation speed of the engine 21 with respect to the first hydraulic pump 22, and by the increase in the opening area of the second hydraulic pump 23 and the increase in the rotation speed of the engine 21. Obtained together.

Thereafter, the speed increase section of the engine 21 ends, and the increase in the rotation speed of the engine 21 stops (FIG. 5).
(Time point F in (a), (b)).

[0065] This in thereafter, the rotational speed of the engine 21, for example because it is constant 950R.Pm, although the discharge oil amount of the first hydraulic pump 22 becomes Q ₁ becomes constant, from the second hydraulic pump 23 by increasing the opening area of the confluence switching valve 32 for controlling the discharge oil amount can flow Q ₂ is to increase the discharge amount of oil supplied to the expansion hydraulic cylinder 12 because it is summed joins (5 (A)).

In this embodiment, as described above, the speed-up section of the engine 21 is set from the time point C to the time point F,
Although the speed increase section in the present invention is added between the time C and the time E, which is the time from the time E to the time F, the speed increase section is implemented only from the time C to the time E, Is also good.

The operation of the embodiment described above is performed in the normal mode of the control modes of the computer 52 in this embodiment, and this embodiment has a slow speed mode in addition to the normal mode.

In the slow speed mode of this embodiment, regardless of the operation amount of the speed control lever 54, the rotation speed of the engine 21 is not increased and the second hydraulic pump 23 passing through the merge switching valve 32 Is prohibited.

Specifically, in the slow speed mode of this embodiment, even if the operation amount of the speed control lever 54 is operated beyond the amount corresponding to the time point C or the time point E, the computer 52 outputs A signal corresponding to each of the accelerator cylinders 37 is not output.

It should be noted that the low speed mode is a mode in which the increase in the rotation speed of the engine 21 is prohibited or the second
If the operation is performed by either one of prohibition of merging of the discharge oil from the hydraulic pump 23, the corresponding signal from the computer 52 to the accelerator cylinder 37 may not be output.

In the embodiment described above, the time when the main valve 25 is fully opened, the time when the engine 21 starts and ends the speed-up section, and the time when the opening of the merge switching valve 32 starts are different. There is an advantage that the flow curve of the amount of oil discharged from the first and second hydraulic pumps 22 and 23 can be smoothly formed, and the actuator such as the telescopic hydraulic cylinder 12 can be easily operated smoothly.

In the embodiment described above, it is assumed that the operation amount of the speed control lever 54 is slightly larger than the operation amount (time point D) corresponding to the completion of the opening operation of the main valve 25. The merging switching valve 32 starts the opening operation (time E).
The present invention is not limited to this, and can be implemented as shown in FIG. 5 (c) or (d). Each point in the following description is the same as in the case of the above embodiment.

That is, FIG. 5C shows the time when the operation amount of the speed control lever 54 is the operation amount corresponding to the completion of the opening operation of the main valve 25 (time point D) and the start of the opening operation of the merge switching valve 32. (Time E) is performed at the same time.

FIG. 5D shows that before the operation amount of the speed control lever 54 is the operation amount corresponding to the completion of the opening operation of the main valve 25 (time point D), the opening of the merging switching valve 32 is started. When the operation is started (time point E) and the speed control lever 54 is further operated by a slight amount from this time point E, the operation amount of the speed control lever 54 is the operation amount corresponding to the completion of the opening operation of the main valve 25. The time point (time point D) is to be reached.

With these arrangements, it is possible to obtain a flow rate characteristic of the discharged oil which is substantially similar to the above embodiment.

In the above-described embodiment, the speed control lever 54 provided on the wireless operation panel 51 as the operation lever has been described. However, the present invention is not limited to this, and the operation lever is directly connected to the main valve. It may be provided.

The hydraulic circuit of the above-described embodiment is of a so-called meter-in type in which the merge switch valve 32 is interposed in series with the merge oil passage 33. In the present application, the merge switch valve 32 is connected in parallel to the hydraulic actuator. It is needless to say that the present invention can be carried out even with a bleed-off type hydraulic circuit interposed in the above.

When the hydraulic circuit is of the bleed-off type as described above, the first hydraulic pump 22 is connected to the first hydraulic pump 22 by connecting the first hydraulic pump 23 with the first hydraulic pump 22. A check valve may be provided to allow the hydraulic pump 22 to flow to the discharge oil passage side and prevent the second hydraulic pump 23 from flowing to the discharge oil passage side.

Further, the present invention can be applied not only to the hydraulic crane described in the embodiment, but also to other working machines (for example, construction machines such as excavators).

[0080]

As described above, according to the first aspect of the present invention, the first hydraulic actuator of the working machine is provided with the first hydraulic actuator.
Increase in the rotational speed of the engine that drives the first and second hydraulic pumps prior to the supply of the discharge oil from the second hydraulic pump when the discharge oil is to be supplied from both the first and second hydraulic pumps Since the section is provided, the rotation speed of the engine can be set lower than in the past when the work machine is driven only by the discharge oil of the first hydraulic pump, and both the first hydraulic pump and the second hydraulic pump can be set. When the work machine is driven by the discharged oil, the engine output sufficient for this can be secured by passing through the speed increasing section.

Accordingly, it is possible to reduce the loss of the output of the engine that drives the hydraulic pump for this type of vehicle-mounted hydraulic working machine, thereby reducing the noise of the engine and improving the fuel efficiency.

[Brief description of the drawings]

FIG. 1 is an overall schematic explanatory diagram of a hydraulic control device according to an embodiment of the present application.

FIG. 2 is a structural explanatory view of a floating device.

FIG. 3 is a view taken in the direction of the arrow X in FIG. 2;

FIG. 4 is a partial cross-sectional view of a connection state between a shaft body and a swing link.

FIGS. 5 (a) and 5 (b) are graphs showing the relationship between the operation amount S of the speed control lever and the discharge oil flow rate Q passing through the main valve, and FIG. 6 is a graph showing a relationship between an operation amount S of a control lever, an engine rotation speed N, an opening area U of a main valve, and an opening area V of a merge switching valve;
(C) and (d) are graphs respectively corresponding to (b) in the modified example.

FIG. 6 is a schematic explanatory side view of a crane truck.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vehicle-mounted hydraulic work machine (crane truck) 2 Vehicle, 4 Work machine (crane) 12 Hydraulic actuator (Hydraulic cylinder for expansion and contraction) 20 Hydraulic control device 21 Vehicle running engine 22 First hydraulic pump 23 Second hydraulic pump 25 Hydraulic switching valve (main valve) 27 Oil tank 32 Control valve (merging switching valve) 54 Operation lever (speed control lever)

Claims (1)

(57) [Scope of request for utility model registration] 1. A first hydraulic pump and a second hydraulic pump driven by a vehicle driving engine are provided, and oil discharged from these hydraulic pumps is guided to a hydraulic actuator to drive a work machine arranged on a vehicle. A hydraulic work machine mounted on a vehicle, comprising: a hydraulic switching valve installed in a discharge oil passage from the first hydraulic pump to the hydraulic actuator; and an operation of adjusting a flow rate of the hydraulic switching valve according to an operation amount. A lever, and a control valve that operates in conjunction with the operation of the operation lever, and connects a discharge oil passage from the second hydraulic pump to a discharge oil passage on the first hydraulic pump side; The operation of the control valve in conjunction with the operation of the lever connects the discharge oil passage from the second hydraulic pump to a tank when the operation amount of the operation lever is equal to or less than a predetermined amount. , If it exceeds a predetermined amount the second
A hydraulic control device for connecting a discharge oil passage from a hydraulic pump to a discharge oil passage on the first hydraulic pump side, wherein at least the control valve controls a discharge oil of a second hydraulic pump to a first hydraulic pump.
A hydraulic control device for a vehicle-mounted hydraulic working machine, wherein a speed-up section for increasing the rotation speed of the vehicle-running engine is provided before the oil is supplied to a discharge oil passage of a hydraulic pump.