JPH0440010Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an operating valve device for a bucket used in a front loader or the like.

(Prior art) Conventionally, in the hydraulic circuit of a bucket in a front loader, etc., a scoop oil chamber of the bucket is installed between the bucket cylinder and a bucket control valve that controls the bucket to increase the speed during dumping operation of the bucket. Some are equipped with a merging type operating valve device that allows the return oil to merge into the dump supply oil path.

That is, as shown in FIG. 7, in this type of valve device, during the scoop operation of the bucket, water is supplied from the scoop supply oil passage 100 through the oil passage 102 in the valve body 101, the check valve body 103, and the oil passage 104. Pressure oil is supplied to the scoop oil chamber 106 of the bucket cylinder 105, and when the bucket is dumping, pressure oil is supplied from the dump supply oil passage 107 to the dump oil chamber 108 of the bucket cylinder 105, and the balance type spool 1
09 in the opening direction and the bucketed cylinder 10
The return oil from the scoop oil chamber 106 of No. 5 is transferred to the oil path 10.
4, 110, a spool 109, and an oil path 111 to join the dump supply oil path 107. Therefore, during the dump operation, the pressure oil from the hydraulic pump and the return oil are combined and supplied to the dump oil chamber 108 of the bucket cylinder 105, so that the dumping speed of the bucket can be increased.

(Problem to be solved by the invention) The conventional valve device has a check valve body 103 and a spool 1.
09 are assembled in different positions within the valve body 101, the number of machining steps on the valve body 101 side increases. It also had the disadvantage of requiring a large number of parts, such as the need for two 113's. Furthermore, there is a drawback that the entire valve device becomes larger.

Therefore, in view of the above-mentioned problems, the present invention aims to reduce the number of parts and processing steps, and to make the entire valve device more compact.

(Means for solving the problem) The present invention supplies pressure oil from the scoop supply oil passage 25 to the scoop oil chamber 26 side of the bucket cylinder 10 via the check valve body 20 when the bucket 9 is scooping. During the dump operation of the bucket 9, the dump oil chamber 3 of the bucket cylinder 10 is connected from the dump supply oil passage 17.
At the same time, the balanced spool 21 is operated in the opening direction to open the bucket cylinder 1.
Dump the return oil of the scoop oil chamber 26 of 0 to the supply oil path 1
In the operating valve device for a bucket, which is configured to join the scoop oil supply passage 25 and the scoop oil chamber 2
The check valve body 20 that opens and closes between the scoop oil chamber 26 and the dump supply oil passage 17 is fitted to the spool 21 that opens and closes between the scoop oil chamber 26 and the dump supply oil passage 17 so as to be able to slide relative to each other in the axial direction. The stop valve body 20 and the spool 21 are assembled into the valve body 15 so as to be freely slidable in the axial direction,
A spring 22 is interposed between the check valve body 20 and the spool 21 to urge both to a closed state, and the spring 22 is closed by the check valve body 20 during the rake operation, and is pressed against the spring 22 during the dump operation. A small hole 29 is provided in the spool 21 to supply return oil from the scoop oil chamber 26 to the oil chamber 28 at one end of the spool 21 so that the spool 21 is slid in the opening direction.

(Function) When the bucket 9 operates as a rake, the check valve body 20
opens against the spring 22, and supplies pressure oil from the scoop supply oil passage 25 to the scoop oil chamber 26 side of the bucket cylinder 10 via the check valve body 20.

During the dump operation of the bucket 9, the dump oil chamber 3 of the bucket cylinder 10 is connected from the dump supply oil passage 17.
Supply pressure oil to 2. On the other hand, bucket cylinder 1
The return oil from the 0 rake oil chamber 26 is sent to the oil chamber 28 through the small hole 29, and thereby the spool 21
operates in the opening direction, so the bucket cylinder 10
Return oil from the rake oil chamber 26 joins the dump supply oil path 17 via the oil path 18, spool 21, and oil path 19, and the bucket cylinder 10 performs a dumping operation at increased speed.

(Embodiment) Hereinafter, an embodiment of the present invention will be described based on the drawings. In FIG. 2, 1 is a tractor body, 2 is a front wheel, and 3 is a rear wheel. Reference numeral 4 denotes a hydraulic system for raising and lowering a working machine mounted at the rear of the tractor body 1. Reference numeral 5 designates a front loader as a working machine, which includes a mounting frame 6 for mounting on the tractor body 1, a pair of left and right booms 7 pivotally connected to the mounting frame 6, and a pair of left and right boom cylinders for raising and lowering the boom 7. 8, a bucket 9 pivotally attached to the tip of the boom 7, and a bucket cylinder 10 for scooping and dumping the bucket 9.

FIG. 3 shows a hydraulic circuit, in which 11 is a boom control valve, 12 is a flow control valve, and 13 is a bucket control valve. 14 is an operating valve device, which is a bucket cylinder 1.
0 and the bucket control valve 13, and is attached to the outside of the bucket cylinder 10.

The operating valve device 14 is constructed as shown in FIG. That is, in FIG. 1, 15 is a valve body, in which a holding hole 16 and a dump supply oil passage 17 are formed in parallel, and the holding hole 1
Oil passages 18 and 19 in a direction perpendicular to 6 are formed in a stepped manner. A check valve body 20 and a balanced spool 21 are slidably fitted into the holding hole 16 on the same axis, and the check valve body 20 and the spool 21 are fitted with a spring interposed between them. It is biased to the closed state at 22. The check valve body 20 has a tapered tip and can freely approach and separate from a valve seat 24 formed between the holding hole 16 and the oil passage 23.
It is designed to open and close between 3 rooms. The oil passage 23 is connected to the bucket control valve 13 via the scoop supply oil passage 25.
In addition, the oil passages 18 are connected to scoop oil chambers 26 of the bucket cylinder 10, respectively. The spool 21 opens and closes the oil passages 18 and 19, and has a small hole 29 that communicates the oil chamber 28 on the blind plug 27 side screwed to the outer end of the holding hole 16 with the oil passage 18. At the same time, a pin 30 is integrally formed in the shaft center portion, and the pin 30 is slidably inserted into the check valve body 20. Note that the oil passage 18 side of the small hole 29 is
When the check valve body 20 is opened, it is closed from the outer peripheral side. The spool 21 is attached to the blind stopper 27.
A stopper 31 is provided which comes into contact with the. The oil passage 19 communicates with a dump supply oil passage 17, and the dump oil supply passage 17 connects the bucket control valve 13 and the dump oil chamber 32 of the bucket cylinder 10.

When scooping up earth and sand with the bucket 9, the bucket control valve 13 is operated to the scoop side. Then,
Pressure oil from the hydraulic pump is sent from the scoop supply oil path 25 to the valve body 15 side, and the check valve body 20 slides to the left against the spring 22 as shown in FIG. 4 by the oil pressure. Pressure oil passes through the oil passage 33, the check valve body 20, and the oil passage 18 to the bucket cylinder 10.
The oil is supplied to the rake oil chamber 26. On the other hand, return oil from the dump oil chamber 32 of the bucket cylinder 10 is returned to the tank via the dump supply oil path 17 and the bucket control valve 13. Therefore, the bucket cylinder 10 contracts, and the bucket 9 rotates upward to perform a scooping action.

When the bucket 9 is in a dump operation, the bucket control valve 13 is operated to the dump side, and the dump supply oil path 17 is opened.
Pressure oil is supplied from the dump oil chamber 32 of the bucket cylinder 10 to the dump oil chamber 32 of the bucket cylinder 10. At this time, the return oil from the scoop oil chamber 26 of the bucket cylinder 10 is sent from the oil passage 18 to the oil chamber 31 side through the small hole 29 of the spool 21, so that the spool 21 is moved toward the spring 22 as shown in FIG.
The bucket cylinder 10 is opened by sliding to the right against the pressure, and the return oil flows through the oil path 18, spool 21, and oil path 19 to the dump supply oil path 17 side, and the bucket cylinder 10 is in an accelerated state. It stretches and Bucket 9 dumps.

When lowering the boom 7, operate the boom control valve 11 to the lowering side to supply pressure oil to the boom cylinder 8.
The oil is supplied to the descending oil chamber 42.

When lowering the boom 7, operate the boom control valve 11 to the lowering side to supply pressure oil to the boom cylinder 8.
The oil is supplied to the descending oil chamber 42.

The operating valve device 14 can also be constructed as shown in FIG. That is, the check valve body 20 is connected to the spool 2
The check valve body 20 is slidably fitted into the fitting hole 43 of the first check valve body 20, and a small hole 44 is formed in the check valve body 20 to communicate the oil passage 18 and the fitting hole 43. Therefore, in this case, the return oil from the oil passage 18 is sent from the small hole 44 to the oil chamber 28 via the fitting hole 43 and the small hole 29. Further, the spool 21 has a flange 45 formed on the oil chamber 28 side, so that the pressure receiving area on the oil chamber 28 side is large.

(Effect of the invention) According to the invention, the check valve body 20 opens and closes between the scoop oil supply passage 25 and the scoop oil chamber 26, and the check valve body 20 opens and closes between the scoop oil chamber 26 and the dump oil supply passage 17. The check valve body 20 and the spool 21 are fitted into the spool 21 so as to be slidable relative to each other in the axial direction, and the check valve body 20 and the spool 21 are assembled into the valve body 15 so as to be slidable in the axial direction. A spring 22 is interposed between the spool 21 and the spring 22 to urge both of them into a closed state, and the check valve body 20 closes the spool 22 during the rake operation, and the spool 22 is moved in the opening direction against the spring 22 during the dump operation. Since the spool 21 is provided with a small hole 29 that supplies the return oil from the scoop oil chamber 26 to the oil chamber 28 at one end of the spool 21 so as to slide, the machining on the valve body 15 side is easier than in the past. Not only can the number of man-hours be reduced, but also the number of parts can be reduced because the spring 22 is used in common, and the overall size can be made more compact.

[Brief explanation of the drawing]

1 to 6 illustrate an embodiment of the present invention, in which FIG. 1 is a sectional view of an operating valve device, FIG. 2 is a side view of a tractor with a front loader, and FIG. 3 is a hydraulic circuit. 4 and 5 are sectional views for explaining the operation of the operating valve device, FIG. 6 is a sectional view of a modified example of the operating valve device, and FIG. 7 is a sectional view showing a conventional example. 9...bucket cylinder, 10...bucket cylinder,
14... Operating valve device, 15... Valve body, 16...
Holding hole, 17...Dump supply oil path, 20...Check valve body, 21...Spool, 22...Spring, 26...
...Squeeze oil room, 32...Dump oil room.

Claims (1)

[Scope of utility model registration request] During the scooping operation of the bucket 9, pressure oil is supplied from the scoop supply oil passage 25 to the scoop oil chamber 26 side of the bucket cylinder 10 via the check valve body 20, and during the dumping operation of the bucket 9, pressure oil is supplied to the scoop oil chamber 26 side of the bucket cylinder 10. Pressure oil is supplied from the pump to the dump oil chamber 32 of the bucket cylinder 10, and the balance type spool 21 is operated in the opening direction so that the return oil from the scoop oil chamber 26 of the bucket cylinder 10 joins the dump oil supply path 17. In the operating valve device for a dump truck, a check valve body 20 opens and closes between the scoop oil supply passage 25 and the dump oil chamber 26, and a check valve body 20 opens and closes between the scoop oil chamber 26 and the dump oil supply passage 17. spool 21
The check valve body 20 and the spool 21 are fitted into the valve body 15 so as to be slidable relative to each other in the axial direction. A spring 22 is interposed between the two to bias the two in a closed state, and the check valve element 20 closes the spool 21 during the rake operation, and the spool 21 slides in the opening direction against the spring 22 during the dump operation. The operating valve device for a bucket bag is characterized in that the spool 21 is provided with a small hole 29 for supplying return oil from the scoop oil chamber 26 to the oil chamber 28 at one end of the spool 21.