JPH0668272B2 - Booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a pressure booster that further boosts the hydraulic pressure sent from a hydraulic pump and sends it out.

(Prior Art) Conventionally, a booster attached to a hydraulic pump guides pressure oil sent from the hydraulic pump into a cylinder provided with a large-diameter piston, and pushes the small-diameter piston with the large-diameter piston. The pressure oil on the secondary side discharged by the small diameter piston was increased. In order to continuously increase the pressure, the flow direction switching valve is operated according to the stroke of the piston so that pressure oil from the hydraulic pump is applied alternately in the forward and backward directions of the piston. I was doing.

(Problems to be Solved by the Invention) In the case of the above-described conventional technique, the flow path direction switching valve uses a pilot operation switching valve or a solenoid operation switching valve, so a valve for pilot operation or other device, Alternatively, there is a problem in that a solenoid and a control circuit for operating the solenoid are required, and the structure of the booster becomes complicated and becomes large and heavy.

The present invention has been made in view of the above-mentioned problems of the conventional technique, and an object thereof is to provide a booster having a simple structure, small in size and light weight, and capable of continuous operation.

[Structure of Invention]

(Means for Solving the Problems) The present invention provides a second cylinder at one port of a first cylinder and a valve body at the other port of the first cylinder so that the chambers of the first cylinder are continuous with each other. The second piston of the second cylinder and the spool of the valve body are directly connected to each other.
The diameter of Piston is smaller than that of the first piston, and the diameter of the spool is thinner than that of the first piston but thicker than that of the second piston. The first cylinder is provided with a drive-side inlet for fluid that communicates with the leading-side chamber on the valve body side,
The valve body is provided with a drive side discharge port, and the spool is connected to the valve body chamber and the first
A first communication hole opening to the forward side chamber of the cylinder, a second communication hole opening to the valve inner chamber and the return side chamber of the first cylinder are provided, and the spool is closed at the retracted position. On the other hand, a shuttle valve that opens the second communication hole and closes both the first and second communication holes at the forward position is slidably fitted, and the first and second communication holes are formed on the inner circumference of the shuttle valve. And a cam surface forming an annular groove in the front and rear portions of the outer peripheral surface of the shuttle valve, the valve body facing the front cam surface in the vicinity of the forward end of the first piston and facing the front cam surface. And a ball for giving an urging force for retreating the shuttle valve in the vicinity of the rearward limit of the first piston, facing the rear cam surface, is urged by a spring to project.

(Operation) The pressure booster of the present invention continuously supplies pressure oil to the drive-side inlet and the pressurizing-side inlet to reciprocate the first and second pistons. It is driven by the difference in the pressure received on the back surface. That is, at the time of the backward movement, the pressure oil from the drive side injection port flows into the forward movement side chamber, but the pressure oil flows from the first communication hole into the backward movement side chamber through the second communication hole. Since the pressure receiving area of the return-side chamber surface of the first piston is larger than the pressure receiving area of the opposite forward-side chamber surface, the first piston moves backward.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

The first cylinder 1 with both ends opened like a cylinder is directly connected to the second cylinder 2 with one opening opened so that both cylinders 1 and 2 are in communication with each other. Cylindrical valve element 3 with the other opening also open on one side
Is provided in a state where the inner chamber of the valve body 3 and the inner chamber of the first cylinder 1 communicate with each other.

The inner diameter of the first cylinder 1 is larger than the inner diameter of the second cylinder 2, and the large diameter first piston 4 of the first cylinder 1
Further, the small diameter second piston 5 of the second cylinder 2 is directly connected integrally.

Further, the spool 6 provided in the valve body 3 is directly connected to the first piston 4 integrally, and the spool 6 is the first piston 4
It is thinner, but thicker than the second piston 5. The inlet of the valve body 3 on the side of the first cylinder 1 prevents fluid leakage by a seal even if the spool 6 slides. The rear part of the valve body 3 is stepwise narrower than the middle part, and the rear part of the valve body 3 is formed in an empty chamber 7 having a diameter larger than that of the spool 6.

Therefore, the area of the pressure receiving surface 4a of the first piston 4 on the protruding side of the second piston 5 is formed to be larger than the area of the pressure receiving surface 4b on the opposite side from which the spool 6 is projected.

A pressure side injection port 8 and a pressure side discharge port 9 are provided in the tip chamber A of the second cylinder 2 via check valves 10 and 11, respectively.

The drive side injection port 12 of the first cylinder 1 is
The cylinder 1 is provided so as to communicate with the forward movement side chamber B on the valve body 3 side, and the valve body 3 is provided with a drive side discharge port 13 so as to communicate with the empty chamber 7.

A first communication hole 14 and a second communication hole 15 are formed in the spool 6 in the axial direction, and are opened in the first communication hole 14 and the second communication hole 15 so as to face the vacant chamber 7 of the valve body 3. The rear openings 16 and 18 are provided one behind the other along the axial direction, and the front opening 17 of the first communication hole 14 is provided opposite to the inside of the forward movement side chamber B of the first cylinder 1 and in front of the second communication hole 15. The port 19 extends the second communication hole 15 to the first piston 4 and the second piston 5, and is opened so as to face the return side chamber C on the second cylinder 2 side of the first cylinder 1.

Further, a shuttle valve 20 is fitted on the outer circumference of the spool 6 so as to be slidable in the axial direction in the vacant chamber 7, and the inner peripheral surface of the shuttle valve 20 has rear openings of the first communication hole 14 and the second communication hole 15, respectively. The shuttle valve 20 is provided with an annular groove 21 that communicates with each other, and cam surfaces 22 and 23 that form annular concave grooves are provided in the front and rear portions of the outer periphery of the shuttle valve 20. By the way, the rear openings 16 and 1 of both the first communication hole 14 and the second communication hole 15
The relationship between 8 and the shuttle valve 20 is such that the rear opening 16 of the first communication hole is closed at the backward limit of the shuttle valve 20, but the rear opening 18 of the second communication hole is opened, and the shuttle valve 20 is moved forward. Thus, the rear ports 16 and 18 of the first and second communication holes are formed so as to be sealed together. A stopper 24 is provided at the rear end of the spool 6 to prevent the shuttle valve 20 from coming off.

On the other hand, as shown in FIG. 4, a pair of balls 25 facing each other are provided on the valve body 3 by a spring 26 so that they can be pressed against the outer circumference of the spool 6, and their positional relationship is as shown in FIG. In the state where the spool 6 and the shuttle valve 20 are located at the backward limit, both balls 25 are provided so as to engage with the front side cam surface 22 and engage with the rear side cam surface 23 when advanced.

Therefore, when the spool 6 moves forward, the shuttle valve
20 is pushed by the stopper 24 and moves forward together with the spool 6, the ball 25 disengages from the front cam surface 22, slides on the outer peripheral surface of the spool 6, and the ball 25 moves to the rear cam surface as shown in FIG. Since the pressing force of the ball 25 acts as a propulsive force for advancing on the inclined surface of the cam surface 23 when trying to fall to 23, the shuttle valve 20 automatically advances as shown by the one-dot chain line, The rear openings 16 and 18 of the second communication hole are sealed together.

Due to the above structure, as shown in FIG.
The operation will be described from the state where the piston 4 is retracted. In this state, the return-side chamber C of the first cylinder 1 and the tip chamber A of the second cylinder 2 are filled with pressure oil. Further, hydraulic pressure is constantly applied to the pressurizing side inlet 8 and the drive side inlet 12 during operation.

Therefore, the pressure oil flows into the forward movement side chamber B from the drive side injection port 12, and the front opening 17 of the first communication hole 14 opens facing the forward movement side chamber B, but the rear opening 16 has the shuttle valve 20. 2nd from the front opening 19 which is closed in
Since it flows in through the communication hole 15 and then the opening 18 is opened, it is discharged from the drive-side discharge port 13 through the empty chamber 7, so that a thrust force to move forward is given to the first piston 4 and the second piston 5 moves forward together. As a result, the pressure oil is increased in pressure and extracted from the pressurizing side discharge port 9.

In this way, at the same time when the first piston 4 reaches the limit of forward movement, the shuttle valve 20 is moved forward by the ball 25 that is independently pressed, and the rear ports 16 and 18 of the first and second communication holes 14 and 15 are set in the empty chamber 7.
Sealed against the annular groove 21 in the shuttle valve 20.
Since the two rear openings 16 and 18 are communicated with each other through the, the pressure oil flowing into the outward side chamber B flows from the front opening 17 of the first communication hole 14 to the front opening 17 of the second communication hole 15. The pressure oil flows into the return-side chamber C. At that time, since the pressure receiving areas of the front and back of the first piston 4 are different and the pressure receiving surface 5a of the second piston 5 is also added, the first piston 4 retracts.

When returning as described above, since the pressure oil in the forward movement side chamber B flows into the backward movement side chamber C and there is a pressure receiving area difference, the first, second pistons 4,5, and The valve body 3 rapidly returns and the above operation is repeated.

〔The invention's effect〕

The constituent elements of the booster according to the present invention are: a) A large-diameter first cylinder and a small-diameter second cylinder and a valve body are connected in series so as to communicate with each other.

B) The diameter of the piston of the second cylinder and the spool of the valve body are both smaller than that of the piston of the first cylinder, and the spool is formed thicker than the piston of the second cylinder.

C) Pressure oil should be supplied only to the forward side chamber of the first piston and the second cylinder.

D) The spool has a first piston leading to the forward side chamber of the first piston.
A shuttle valve that has a communication hole and a second communication hole that communicates with the return chamber, and is slidably fitted to the spool. When discharging, the pressure oil in the forward chamber can be switched so as to flow into the backward chamber through the first and second communication holes.

Therefore, since the pressure oil is supplied only to the forward-moving chamber of the first piston and the second cylinder, the switching valve is unnecessary in those supply system circuits.

Also, although the pressure oil is supplied only to the forward side chamber and the second cylinder of the first piston, the pressure oil in the forward side chamber is made to flow into the return side chamber by switching the shuttle valve, and the pressure received on the front and back sides of the first piston is also received. Since the area is different, the pressure oil rapidly flows into the return side chamber, and the pressure received by the second piston is also added, which is far more than the conventional pressure oil switching that supplies different ports. It operates quickly.

Further, since the second cylinder having a small diameter and the valve body are connected to each other before and after the first cylinder so that the inside of the cylinder communicates with each other, the structure is simplified, and further, the compactness is achieved and the large pressure boosting is achieved. Can be obtained.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing a state in which the booster according to the present invention is returned, FIG. 2 is a right side view, FIG. 3 is a left side view, and FIG. 4 is a first A-A. Sectional view taken along the line of arrow 5,
FIG. 7 is a sectional view taken along the line BB in FIG. 1, FIG. 6 is a longitudinal sectional view showing a state of the booster according to the present invention when it is moved forward, and FIG.
The figure is an explanatory view showing the sliding action of the shuttle valve. 1 ... First cylinder, 2 ... Second cylinder 3 ... Valve element, 4 ... First piston, 5 ... Second piston, 6 ... Spool, 8 ... Pressure side inlet 9 ... Pressure side Discharge port, 12 …… Drive side inlet port 13 …… Drive side discharge port, 14 …… First communication hole 15 …… Second communication hole, 20 …… Shuttle valve 22,23 …… Cam surface, 25 …… Ball A: Tip chamber, B: Forward chamber, C: Return chamber

Claims (1)

[Claims] 1. A first cylinder of a first cylinder (1) is provided with a second cylinder (2) at one port and a valve body (3) at the other port in a continuous manner in each chamber. 4) The second piston (5) of the second cylinder and the spool (6) of the valve body are directly connected to each other, and the diameter of the second piston (5) is smaller than that of the first piston (4). The diameter of (6) is smaller than that of the first piston (4), but is larger than that of the second piston (5), and the tip end chamber (A) of the second cylinder is added to the fluid pressure side injection port (8). The first cylinder is provided with a pressure side discharge port (9), and the first cylinder is provided with a drive side injection port (12) for the fluid communicating with the forward side chamber (B) of the valve body side, and the valve body is provided with a drive side discharge port (13). , The first opening on the spool into the valve body chamber and the forward side chamber (B) of the first cylinder
A communication hole (14) and a second communication hole (15) opening to the valve body chamber and the return side chamber (C) of the first cylinder are provided, and the spool is closed at the first communication hole opening at the retracted position. A shuttle valve (20) that opens the second communication hole opening and closes both the first and second communication hole openings at the forward position is slidably fitted, and the first and second communication holes are connected to the inner circumference of the shuttle valve. An annular groove (21) that connects the hole openings to each other is provided, and cam surfaces (22, 23) that form an annular groove are provided in the front and rear portions of the outer peripheral surface of the shuttle valve, and the valve body is provided near the forward limit of the first Pistonton. Front cam surface (22)
The ball (25), which moves the shuttle valve forward in the vicinity of the rear end of the first piston and which gives the biasing force for retracting the shuttle valve in the vicinity of the rear cam surface (23), by the spring (26). A pressure booster characterized by being urged to project.