JP2863410B2 - Valve device for regeneration circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regeneration circuit for increasing the speed of a hydraulic cylinder provided in a working machine such as a hydraulic shovel by using (regenerating) hydraulic oil discharged from a tank by the hydraulic cylinder. The present invention relates to a valve device.

[0002]

2. Description of the Related Art There are many types of mechanisms driven by hydraulic cylinders. For example, in the case of a hydraulic shovel, there are a boom, an arm, a bucket, and various attachments attached in place of the bucket. Some of these mechanisms require an increase in working speed during the work process. For example, a crusher used as the attachment is a mechanism for crushing an object to be crushed, but it is desirable that the crusher be driven at a high speed until the object is sandwiched in terms of work efficiency.

[0003] Further, there is a demand for speed increase in the following cases. That is, when the attachment is mounted on the main body and driven, if the designed maximum pressure of the attachment is lower than the maximum pressure of the main body, the supply amount of the pressurized oil to the attachment becomes small, and the working speed may be reduced. In such a case, the speed of the attachment must be increased.

[0004] Such a mechanism that requires an increase in speed naturally has means for increasing the speed of a hydraulic cylinder that drives the mechanism. The present applicant has filed Japanese Patent Application No. 4-2318.
No. 20 proposed a valve device capable of increasing the speed without being affected by the use of another hydraulic actuator as such a speed increasing means. This valve device will be described with reference to the drawings.

FIG. 2 is a hydraulic circuit diagram of a valve device for a regeneration circuit according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a hydraulic pump, 2 a hydraulic cylinder, 3 is flow system valve that controls the driving direction and the driving speed of the hydraulic cylinders 2, 4 relief valve, 5 is the tank. Reference numerals 30 and 31 denote flow control valves of a hydraulic actuator (not shown).

Reference numeral 10 denotes a valve device for a regeneration circuit. The regeneration circuit valve device 10 includes a check valve 11, a main valve 12, a pressure setting valve 13, a shuttle valve 14, a switching valve 15, and pilot lines 16, 17, and 18. D ₁ ,
D ₂ and D ₃ indicate valve ports of the valve device 10 for the regeneration circuit,
The regenerating circuit valve device 10 includes these valve ports D ₁ , D ₂ , D
_{At 3} , it is connected to the main pipeline of the normal hydraulic actuator (the bottom pipeline and the rod pipeline of the hydraulic cylinder 2 in the illustrated case).

The main valve 12 is a valve 12v which receives the pressure on the rod side of the hydraulic cylinder 2, and a spring 12 which presses the valve 12v.
b and a chamber 12r on the side of the spring 12b. The pressure setting valve 13 includes a valve 13v that shuts off and opens a through hole communicating with the chamber 12r of the main valve 12, a spring 13b that presses the valve 13v in a shut off state, and a vent port 13p that communicates with a bottom-side conduit. ing.

The switching valve 15 has a port connected to the rod side pipe, a port connected to the flow control valve, and a pilot port for introducing the pressure of the bottom side pipe. When the pressure is equal to or less than the value, the state shown in the drawing, that is, the state in which the throttle 15s is interposed, is set. Shuttle valve 14 is connected to pilot line 16
And the outlet pressure of the switching valve 15 guided by the pilot line 17 are introduced, and the higher pressure is applied through the pilot line 18 to the chamber 1 of the main valve 12.
Lead to 2r.

Next, the operation of the valve device 10 will be described.
When the flow control valve 3 is switched to the position B, the pressure oil of the hydraulic pump 1 is supplied to the rod side of the hydraulic cylinder 2 via the check valve 11, and the pressure oil on the bottom side of the hydraulic cylinder 2 is supplied to the flow control valve. 3 to the tank 5. As a result, the hydraulic cylinder 2 is driven to contract the rod as in the normal case.

When the flow control valve 3 is switched to the position A, the pressure oil of the hydraulic pump 1 is supplied to the bottom side of the hydraulic cylinder 2 and the rod is driven in the extending direction. At this time,
When the load on the hydraulic cylinder 2 is small and the bottom pressure is low,
The switching valve 15 is switched to the illustrated position where the throttle 15s is interposed, and a small amount of the pressure oil on the rod side of the hydraulic cylinder 2 passes through the small-diameter hole of the throttle 15s of the switching valve 15 and passes through the flow control valve 3. Drained into tank.

On the other hand, the pressure on the rod side is
v and opens it against the spring 12b, whereby the rod-side pipe and the bottom-side pipe conduct, and most of the pressure oil from the rod of the hydraulic cylinder 2 (pressure oil flowing through the throttle 15s). Other pressure oil) is returned to the bottom side, and the elongation of the rod is accelerated. Since this recirculation is performed directly to the bottom side instead of the upstream side of the flow control valve 3 as in the conventional case, it is independent of the drive of other actuators, and the hydraulic cylinder 2 to be increased in speed must be surely increased in speed. Can be.

In this state, when the load on the hydraulic cylinder 2 increases and the pressure on the bottom side increases and exceeds a predetermined pressure, the switching valve 15 is switched from the position shown in the drawing to a conduction position in which the throttle 15s is not interposed. On the other hand, the pressure on the bottom side is guided to the chamber 12r of the main valve 12 through the pilot line 16, the shuttle valve 14, and the pilot line 18, and
Close v. As a result, the pressure oil on the rod side of the hydraulic cylinder 2 is discharged to the tank via the switching valve 15 and the flow control valve 3, so that the hydraulic cylinder 2 can secure its thrust against an increased load. it can.

When the flow control valve 3 is in the neutral position in the figure, if the pressure is applied to the bottom side of the hydraulic cylinder 2 due to gravity or the like and the rod is extended, the switching valve 1
5 is blocked by the flow control valve 3 and the main valve 12
, The pressure on the rod side is
s, the pilot pipe 17, the shuttle valve 14, and the pilot pipe 18 are introduced into the chamber 12r of the main valve 12 to close the valve 12v, so that there is no discharge path for the pressure oil on the rod side, and the neutral Movement of the rod in position is prevented, and the stop position is reliably maintained.

Further, if an abnormally high pressure is generated on the rod side for any reason, this high pressure is applied to the main valve 12 through the above-described path.
And opens the valve 13v of the pressure setting valve 13 against the spring 13b. Thus, the pressure oil on the rod side is supplied to the throttle 15 s of the switching valve 15, the pilot line 17, the shuttle valve 14, the pilot line 18, and the chamber 12 of the main valve 12.
r, flows through the through hole of the pressure setting valve 13 and the vent port 13p of the pressure setting valve 13 to the bottom side pipeline, and this flow causes a pressure difference before and after the throttle 15s, and this pressure difference causes the main valve 12 The valve 12v opens to release the pressure oil on the rod side to the bottom side. As a result, damage to the rod-side conduit, the main valve 12, and the like can be prevented.

[0015]

By the way, as shown in FIG. 2, the valve device 10 for a regeneration circuit usually has valve ports D _{1 to} D in the middle of the pipe between the flow control valve and the hydraulic actuator. It is arranged using _three . This arrangement will be described with an example of the arrangement of a hydraulic shovel. FIG. 3 is a side view of the excavator. In this figure, 20 is a lower traveling body, 21 is an upper revolving superstructure, 22 is a boom, and 23 is an arm. Arm 2
Attachments such as a bucket and a crusher are rotatably attached to the tip 23a of the third. Reference numeral 22a indicates a mounting portion of the regeneration circuit valve device 10.

FIG. 4 is a plan view of the mounting location 22a shown in FIG. 3 (a view of the mounting location 22a from above in FIG. 3). In this figure, 2 is a hydraulic cylinder shown in FIG. 2, and 10 is a valve device for a regeneration circuit. Reference numeral 22b denotes frames on both sides of the boom 22, and various pipes to the hydraulic actuator are provided through these locations. In the figure, only the pipe L to the hydraulic cylinder 2 is shown. D _{1 to} D ₃ are shown in FIG.
A pipe joint which corresponds to the valve port D ₁ to D ₃ shown in.

The operation of the valve device 10 mounted as described above is as described above. However, when an attachment that does not require a regeneration circuit is mounted as an attachment, an unnecessary speed increase occurs in this state, and the speed increases. The attachment cannot be operated normally. In this case, the reproduction circuit valve device 10 is re when it will be removed from the circuit using the pipe joint D ₁ to D _3, such removal, the attachment further requiring recovery circuit is used It takes a lot of trouble and time to install,
In addition, there is a problem that oil leakage occurs.

An object of the present invention is to solve the problems in the above technology and to provide a valve device for a regeneration circuit which does not need to be attached to or detached from any attachment.

[0019]

In order to achieve the above object, the present invention provides a hydraulic pump, a hydraulic actuator driven by the hydraulic pump, and a hydraulic pump interposed between the hydraulic pump and the hydraulic actuator. A flow control valve for controlling the driving of a hydraulic actuator;
It is switched by the differential pressure between the one side pipe of the eta and the chamber,
A main valve that conducts and shuts off between the one side line and the other side line of the hydraulic actuator, and the pressure of the other side line interposed between the one side line and the flow rate control valve. A switching valve for switching the state of the hydraulic circuit between the one-side conduit and the flow control valve from a conductive state to a throttled state when the pressure is equal to or less than a predetermined value; A regenerative circuit valve device comprising a pilot line for introducing a higher pressure into the chamber of the main valve, a stop valve, in parallel with the switching valve, by opening and closing the stop valve.
A first check valve that opens and closes the pressure oil in the one-side conduit;
Characterized in that connecting a series circuit formed more and the second check valve.

[0020]

When the attachment requiring the speed increase is attached, the stop valve is closed. In this state, when the flow control valve is switched and the hydraulic actuator, for example, the hydraulic cylinder is driven in the direction to extend the rod, the first check valve is in the shut-off state, the load on the hydraulic cylinder is light, and the bottom side pressure is reduced. When the pressure does not rise, the state of the hydraulic circuit between the rod-side pipeline and the flow control valve is switched to the throttle state. In this state, a small amount of the pressure oil from the rod side is discharged to the tank through the throttle, and most of the pressure oil is directly returned to the bottom side pipe line by opening the main valve, and The speed increase is performed.
On the other hand, when the load on the hydraulic cylinder is large, the main valve is shut off and the switching valve is switched to the conductive state. Thereby, the thrust of the hydraulic cylinder is sufficiently secured for the large load. When the flow control valve is switched in a direction to contract the rod, the pressure oil from the flow control valve pushes the first check valve open and is supplied to the rod side.

When an attachment that does not require speed increase is attached, the stop valve is made conductive. In this state, when the flow control valve is switched and the hydraulic cylinder is driven in the direction to extend the rod, the pressure oil from the rod opens the first check valve and is discharged to the tank via the flow control valve. Therefore, the main valve does not open and no speed increase is performed. When the flow control valve is switched in the direction to retract the rod, the pressure oil from the flow control valve pushes the first check valve open and is supplied to the rod side.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiment.

FIG. 1 is a hydraulic circuit diagram of a valve device for a regeneration circuit according to an embodiment of the present invention. In this figure, the same or equivalent parts as those shown in FIG. Reference numeral 25 denotes a valve device for a regeneration circuit according to the present embodiment. 17s
Is a diaphragm interposed in the pilot circuit 17. Reference numeral 26 denotes a check valve. The check valve 26 includes a valve 26v, a spring 26b for urging the valve 26v in a closing direction, a spring chamber 26r of the spring 26b, and a spring chamber 26r in the valve 26v and an external conduit L _2. And a stop 26s formed in a passage between the diaphragm 26s. Further, the check valve 26 is connected in line with conduit L ₁ between the outlet and the port D ₁ of the switching valve 15. 27 is a pilot circuit for connecting the spring chamber 26r of the conduit and the check valve 26 between the outlet and the port D ₁ of the switching valve 15. 28 is a stop valve and 29 is a check valve, which are interposed in the pilot circuit 27.

Next, the operation of this embodiment will be described. If an attachment that requires a regeneration circuit is installed,
The stop valve 28 is manually or electrically closed. In this state, when the flow control valve 3 is switched to the position A, the pressure oil of the hydraulic pump 1 is supplied to the bottom side of the hydraulic cylinder 2. In this case, since the stop valve 28 is closed, the oil on the rod side of the hydraulic cylinder 2
And no differential pressure is generated here.
Is in the shut-off state. Therefore, the valve device 25 for the regeneration circuit
Is the same as the operation of the regeneration circuit valve device 10 shown in FIG. 2, and the speed increase and the thrust generation are performed.

[0025] Further, if the flow control valve 3 is switched to the B position, the pressure oil of the hydraulic pump 1 is supplied to the check valve 26 via line L ₁ pushes open this, the check valve 26 in FIG. 2 performs the same function as the check valve 11, and the rod of the hydraulic cylinder 2 is contracted similarly to the regeneration circuit 10 of FIG.

On the other hand, when an attachment that does not require a regeneration circuit is attached, the stop valve 28 is turned on manually or electrically. In this state, when the flow control valve 3 is switched to the position A, the pressure oil of the hydraulic pump 1 is supplied to the bottom side of the hydraulic cylinder 2. In this case, since the stop valve 28 is in the conducting state, the oil on the rod side of the hydraulic cylinder 2 flows through the throttle 26s of the check valve 26, thereby generating a differential pressure in the throttle 26s.
Opening against the valve 26v spring 26b pressure, oil in the rod side pipe L _2, check valve 26, and is discharged to the tank via line L _1. Therefore, the throttle 15s of the switching valve 15
No oil flows and no differential pressure is generated, so that the main valve 12 is in a shut-off state, and thus no speed increase is performed. When the flow control valve 3 is switched to the position B, the check valve 29
Has the same function as when the stop valve 28 is closed, so that the rod is contracted by the same action as in the above case.

As described above, in this embodiment, the series circuit of the check valves 26, 29 and the stop valve 28 is connected in parallel with the switching valve 15, and when an attachment requiring a speed increase is mounted, the stop is performed. Since the valve 28 is shut off and the stop valve 28 is made conductive when an attachment that does not require speed increase is attached, it is unnecessary to attach or remove the regeneration circuit to any attachment. be able to.

The diaphragm 17 provided in the pilot circuit 17
s is selected to be smaller than the stop 15s of the switching valve 15, and has the following function. That is, in the configuration shown in FIG. 2, the throttle 15s is a throttle that is used for both relief and load holding. If the flow control valve 3 is suddenly stopped during speed-up, overrun occurs in the cylinder. It is necessary to increase 15s. However, by providing the aperture 17s as in the present embodiment, the aperture 17s can be provided with a relief function, and the function of the aperture 15s can be only to hold the load, so that the aperture 15s does not need to be enlarged.

The pressure setting valve 1 in the regeneration circuit
3 is not always necessary. Also, switch the switching valve 15 to the throttle 1
Although the example in which the switching position and the conduction position with 5 s are interposed has been described, the present invention is not limited to this.
The switching position where 5 s is interposed may be set to the cutoff position, and a diaphragm equivalent to the diaphragm 15 s may be connected to the switching valve 15 in parallel.

[0030]

As described above, according to the present invention, a series circuit including the first check valve, the second check valve and the stop valve is connected in parallel with the switching valve, and the first valve is opened and closed by opening and closing the stop valve.
The check valve is opened and closed to select whether acceleration is required or not. Therefore, it is not necessary to attach or remove the regeneration circuit to any attachment.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a valve device for a regeneration circuit according to an embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a proposed valve device for a regeneration circuit.

FIG. 3 is a side view of the hydraulic excavator.

FIG. 4 is a plan view of an installation location of a valve device for a regeneration circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic pump 2 Hydraulic cylinder 3 Flow control valve 10 Regeneration circuit valve device 11 Check valve 12 Main valve 13 Pressure setting valve 14 Shuttle valve 15 Switching valve 15s, 26s Restriction 16, 17, 18 Pilot line 26, 29 Check valve 26v Valve 28 Stop valve

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Takahashi 650, Kandate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Inside the Tsuchiura Plant (56) References JP-A-53-104083 (JP, A) JP-A-2-88004 (JP, U) JP-A-55-170503 (JP, U) JP-A-3-103344 (JP, A) U) (58) Fields surveyed (Int. Cl. ⁶ , DB name) F15B 11/024 E02F 9/22

Claims (1)

(57) [Claims] 1. A hydraulic pump, a hydraulic actuator driven by the hydraulic pump, a flow control valve interposed between the hydraulic pump and the hydraulic actuator to control the driving of the hydraulic actuator, and a hydraulic actuator
It is switched by the differential pressure between the one side pipe of the eta and the chamber,
A main valve that conducts and shuts off between the one side line and the other side line of the hydraulic actuator, and the pressure of the other side line interposed between the one side line and the flow rate control valve. A switching valve for switching the state of the hydraulic circuit between the one-side pipe and the flow control valve from a conductive state to a throttled state when the pressure is equal to or less than a predetermined value; a pressure in the other-side pipe and an outlet pressure of the switching valve A regenerative circuit valve device comprising a pilot line for introducing a higher pressure into the chamber of the main valve, wherein a stop valve and an open / close of the stop valve are provided in parallel with the switching valve .
First check valve for opening and closing the pressure oil in the one side pipe
When, this <br/> a reproducing circuit valve device, characterized in that connecting a series circuit formed more and the second check valve.