JPH01206181A - Valve device - Google Patents

Abstract

PURPOSE:To reduce the attaching area of a valve device, to enhance the responsiveness thereof and the enable slight flow control by attaching a poppet and an orifice valve in an attaching hole formed in a valve body, and by providing a check-valve in a communication hole formed in the poppet along the center axis of the latter. CONSTITUTION:A poppet 37 and a sleeve 27 are fitted in an attaching hole 26 formed in the upper part of a valve body 20, a spool 43 having an oil passage 45, a shank 46 and a cut-out 47 is fitted in an axial hole 42 in the poppet 37 while a check valve 48 is disposed in a small aperture 40 in the poppet 37. With this arrangement, the valve body 40 may be miniaturized, and the valve device may be made to be compact as a whole so that it is possible to reduce the attaching area of the device. Further, the flow rate of fluid from an inlet port 24 is controlled by controlling the flow rate of fluid flowing through the inlet port 24 at a slight value, thereby it is possible to enhance the responsiveness and to control the flow rate at a slight value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve device having a flow rate control function used in a hydraulic circuit of a construction machine or the like.

[Conventional technology]

Construction machines, such as power excavators, have an arm pivotally attached to the vehicle body that can be moved up and down by an arm cylinder, and a boom that can be moved up and down by the boom cylinder.
The boom is equipped with a two-arm working machine with a packet attached to it using a packet cylinder so that it can move up and down.

For example, as shown in FIG. 2, the hydraulic circuit of such an arm-type work machine includes an arm valve, a boom valve 3, and a packet valve 4 in the discharge path 1a of the pump 1, and the arm cylinder, boom cylinder 6, and packet valve 4 are connected to the discharge path 1a of the pump 1. A hydraulic circuit that supplies pressure oil discharged from the pump 1 to a cylinder is known.

In such a hydraulic circuit, when the arm cylinder 5 and boom cylinder 6 are operated simultaneously, the pressure oil of the pump 1 is supplied to the cylinder with a light load. A valve 8 and a check valve 9 are provided in series, and when the arm cylinder 5 and boom cylinder 6 are operated simultaneously, the flow rate restricting valve 8 is controlled and the flow rate flowing to the arm valve 2 is restricted, and the flow rate between the arm cylinder 5 and boom cylinder 6 is controlled. is operated at the same speed regardless of the magnitude of the load, and the check valve 9 prevents backflow from the arm valve 2 side.

The aforementioned flow rate restricting valve 8 and check valve 9 are attached to the valve body 10 of the arm valve 2, as shown in FIG. 3, so that the arm valve 2 serves as a valve device having a flow control function.

That is, the main spool 11 of the arm valve 2, the spool 12 of the flow rate restrictor 8, and the spool 13 of the check valve 9 are attached to the valve body 10, and by sliding the spool 12 left and right, the inlet hole 14 and the outlet hole 15 Main spool 11 by increasing or decreasing the communication area of
The spool 13 is pressed by a spring 17 against a hole 16 communicating between the inlet hole 14 and the outlet hole 15 so that the flow does not flow from the outlet hole 15 to the inlet hole 14.

[Three problems to be solved by the invention] In this valve device, the main spool 11,
Since the spools 12 and 13 are installed separately, the valve body 10 becomes large and the entire valve device becomes large.
Installation requires a large area.

Therefore, an object of the present invention is to provide a valve device that can solve the above problems.

[Means and actions for solving the problem] A main spool that disconnects the inlet port and the outlet port is provided in the valve body, and a mounting hole is bored in the valve body, and the upstream port and the inlet port are connected in the mounting hole. By providing an open-circuit poppet and a throttle valve operated by an external signal to control the operation of the poppet, the flow rate flowing from the upstream port to the inlet port can be controlled, resulting in a valve device having a flow rate control function, and the whole can be made compact. This is how it was done.

〔Example〕

As shown in FIG. 1, a shaft hole 21 is bored in the left-right direction in the valve body 20, and a main spool 22 is inserted into this shaft hole 21 so that the outlet port 23 and the inlet port 24 are disconnected. The outlet port 23 is in communication with the cylinder 25, and a mounting hole 26 is provided in the upper part of the valve body 20.
is vertically bored out of phase with the shaft hole 21 by 90 degrees, and this mounting hole 26 has a poppet 37 that disconnects the inlet hole 31 communicating with the upstream port 35 and the outlet hole 36 communicating with the inlet port 24. and the sleeve 27 are fitted and inserted to form a first chamber 39 between them, and the pressure inside the first chamber 39 presses the conical surface 37a of the poppet 37 against the seat seat 38, thereby opening the inlet hole 31 and the outlet hole 36. It is intended to be blocked.

A small diameter hole 40, a large diameter hole 41, and a shaft hole 42 are continuously drilled in the axial center of the poppet 37, and a spool 43 is inserted into the shaft hole 42, and the flange 44 of this spool 43 connects the hole of the sleeve 27. 27a and the notch 44
a, and the spool 43 has an oil passage 45 and a constricted portion 4.
6. A notch 47 is formed to constitute a communication path that communicates the first chamber 39 and the inlet hole 31, and the needle valve 4 is inserted into the small hole 40.
8 is pressed by a spring 49 to form a reverse valve that shuts off the small hole 40 and the large diameter hole 41, and the spool 5 is inserted into the hole 27a of the sleeve.
0 to form a second chamber 51, the spool 50 is moved upward by a spring 52 and comes into contact with a proportional solenoid 53, and the spool 50 is fitted with a second chamber 51 and a second chamber 51.
7b is drilled through the drill hole 54 communicating with the valve body 2.
A passage 55 communicating the second chamber 51 and the outlet hole 36 is perforated in the sleeve 27 and the second chamber 51 .

Next, the operation will be explained.

When the proportional solenoid 53 is not energized.

Since the spool 50 is moved upward in the figure by the spring 52,
The communication area A3 between the second chamber 51 and the passage 55 determined by the spool 50 is maximized, and the first chamber 39 passes through the notch 44a1, the second chamber 51, the passage 55, and the outlet hole 36.
communicate with.

For this reason, the pressure in the first chamber 39 becomes low and the poppet 3
7 is moved upward by the upstream pressure P1 acting on the conical surface 37a, the conical surface 37a is separated from the seat seat 38, and the pressure oil in the inlet hole 31 flows out to the outlet hole 36.

At this time, a part of the pressure oil in the inlet hole 31 pushes up the needle valve 48 and opens the small hole 40, the large diameter hole 41, the notch 47, the constriction 46, the oil passage 45, the first chamber 39, the notch 44a1, and the second chamber. 51,
Although it flows from the passage 55 to the outlet hole 3B, the poppet 37 has moved upward and the opening area of the notch 47 and the large diameter hole 41 has become large, so the flow rate is maximized.

When the proportional solenoid 53 is energized.

The spool 50 moves downward against the spring 52 by the thrust of the proportional solenoid 53, and the communication area A3 decreases.

For this reason, the pressure oil in the first chamber 39 becomes difficult to flow to the outlet hole 3B, the pressure P3 in the first chamber 39 increases, and the upward stroke of the poppet 37 is restricted. In other words, the second
The communication between the chamber 51 and the passage 55 is narrowed by the spool 50 and the first
Since the pressure P3 in the chamber 39 increases, the poppet 37 is pushed down due to the balance between the upstream pressure P, X pressure receiving area A1 and the first chamber pressure P3X pressure receiving area A2.

At this time, the opening areas of the notch 47 and the large diameter hole 41 are reduced.

As a result, the communication area between the inlet hole 31 and the outlet hole 36 is determined, and the flow rate flowing from the inlet hole 31 to the outlet hole 36 becomes a value proportional to the amount of current supplied to the proportional solenoid 53.

In this state, the poppet 37 is set at the pressure P1 of the inlet hole 31.
When pushed up, the opening area of the notch 47 and the large diameter hole 41 increases, the flow rate flowing into the first chamber 39 increases, and the first chamber 3
Since the pressure P3 inside the proportional solenoid 53 increases and the poppet 37 is pushed down, the communication area between the inlet hole 31 and the outlet hole 36 becomes a value commensurate with the amount of current supplied to the proportional solenoid 53.

Furthermore, when the current applied to the proportional solenoid 53 increases, the spool 50 further strokes downward and narrows the above-mentioned communication area A3 to a smaller value, so that the pressure inside the first chamber 39 P
3 becomes higher, the poppet 37 is further pushed down, and the communication area between the inlet hole 31 and the outlet hole 36 is further reduced.

In this way, the flow rate flowing into the outlet hole 36 can be controlled depending on the magnitude of the current to the proportional solenoid 53.

Furthermore, when the pressure P2 in the outlet hole 36 is higher than the pressure P in the inlet hole 31, the pressure oil in the outlet hole 36 flows through the passage 55 and into the second chamber 5.
1. Notch 44a1, first chamber 39, oil passage 45, constriction 4
6. Inlet hole 3 from notch 47, large diameter hole 41, and small diameter hole 40
1, but since the flow from the large diameter hole 41 to the small diameter hole 40 is blocked by the needle valve 48, the aforementioned flow does not occur, and moreover, the pressure P2 of the outlet hole 36 acts on the first chamber 39. Since the poppet 37 is pushed down and the conical surface 37a is brought into pressure contact with the seat seat 38, the pressure oil in the outlet hole 36 does not flow back into the inlet hole 31.

Moreover, when the pressure difference between the pressure P1 of the inlet hole 31 and the pressure P2 of the outlet hole 36 increases, the flow rate flowing into the first chamber 39 increases,
The flow rate flowing from the first chamber 39 to the outlet hole 36 is restricted by the spool 50, but when the flow rate flowing to the second chamber 51 increases, a larger fluid force acts on the spool 50 due to the flow force (jet flow). This fluid force causes the spool 50 to
is moved downward to reduce the communication area A3,
The pressure P3 in the first chamber 39 becomes high, and the poppet 37 is pushed down to reduce the communication area between the inlet hole 31 and the outlet hole 36, so that the flow rate of the outlet hole 36 can be maintained constant.

That is, it has a pressure compensation function that keeps the flow rate of the outlet hole 36 constant even if the differential pressure between the inlet hole 31 and the outlet hole 36 changes.

Although the communication area between the second chamber 51 and the passage 55 is controlled by stroking the spool 50 with the proportional solenoid 53, the spool 50 may be stroked using pilot pressure.

In other words, a throttle valve that increases or decreases the communication area between the first chamber 39 and the outlet hole 36 based on an external signal may be provided.

Note that the needle valve 48 and the spring 49 are omitted, and the lower end of the spool 43 is made into a conical shape that closely fits into the small diameter hole 40, so that the outlet hole 3
When the pressure P2 of 6 is higher than the pressure P1 of the inlet hole 31, the spool 43 is moved downward by the pressure P2 of the outlet hole 36, and the conical part is brought into close contact with the small hole 40, so that it is closer to the inlet hole 3 than the outlet hole 36.
It may be possible to prevent the flow from flowing back to 1.

〔Effect of the invention〕

Since the poppet 37 and the throttle valve are installed in the mounting hole 26 formed in the valve body 20, and the check valve is provided in the communication hole drilled in the axis of the poppet 37, the valve body 20 can be made smaller and the entire valve device can be made smaller. Since it can be made compact, the installation area can be reduced.

In addition, since the flow rate of the inlet port 24 is controlled by controlling the small amount of flow that flows from the communication hole of the poppet 37 to the inlet port 24 via the first chamber 39 with a throttle valve, responsiveness is improved and the small external It can be controlled by signals and the flow rate can be minutely controlled.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a conventional circuit diagram, and FIG. 3 is a sectional view of an arm valve. 20 is a valve body, 21 is a shaft hole, 22 is a main spool, 23 is an outlet port, 24 is an inlet port, 26 is a mounting hole, 35 is an upstream port, 37 is a poppet, and 39 is a first chamber. Applicant Komatsu Manufacturing Co., Ltd. Representative Patent Attorney Masaaki Yonehara

Claims (1)

[Claims] A main spool 22 that connects the inlet port 24 and the outlet port 23 is fitted into the shaft hole 21 bored in the valve body 20, and a mounting hole 26 is formed in the valve body 20 so as to be perpendicular to the shaft hole 21. a poppet 37 that is bored in the mounting hole 26 and that disconnects the inlet port 24 and the upstream port 35; a first chamber 39 that moves the poppet 37 in a direction that blocks the inlet port 24 and the upstream port 35; The first room 3
9 and the outlet port 23 are each provided with a throttle valve that increases or decreases the communication area between the upstream port 35 and the first chamber 39 in response to an external signal. A valve device characterized in that a check valve is provided in the passageway to prevent backflow from the inlet port 24 to the upstream port 35.