JPH0575501U - Booster - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a pressure increasing device that can be reliably restarted. [Structure] The pressure increasing chambers 8a, 8b and the pistons 6a, 6b partitioning the drive chambers 9a, 9b are connected by a rod 7, and the push rods 22a, 22b of the switching valve 13 are connected to the rod 7 near the end of the stroke. Before pressing
Discharge passages 27a and 27b for discharging the secondary side fluid of the pressure boosting chambers 8a and 8b to the low pressure side are provided. [Effect] Since the driving force of the piston increases near the end of the stroke, it is possible to reliably switch the communication between the ports of the switching valve.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pressure boosting device that boosts and outputs fluid pressure.

[0002]

[Prior Art]

 As shown in FIG. 9, a known pressure booster includes a main body block 1 having an inlet port 2, an outlet port 3 and a discharge port 4, and a pair of cylinders 5A and 5B provided on both sides of the main body block 1. The pistons 6a and 6b are connected to each other by a rod 7 that hermetically penetrates the main body block 1, and in both cylinders 5A and 5B, the pistons 6a and 6b are used to inward (inner side of the main body block 1) and the outer side thereof, respectively. The pressure boosting chambers 8a and 8b and the drive chambers 9a and 9b are partitioned and formed. Further, inlet check valves 10a and 10b, outlet check valves 11a and 11b, a cabana 12 and a switching valve 13 are incorporated in the fluid passage formed in the main body block 1, respectively. The inlet check valves 10a and 10b allow only the inflow of fluid from the inlet port 2 to the pressure increasing chambers 8a and 8b, and the outlet check valves 11a and 11b allow the fluid to flow from the pressure increasing chambers 8a and 8b to the outlet port 3. It only allows outflow. Further, the cabana 12 is for controlling the output pressure of the outlet port 3, and the switching valve 13 switches and communicates one of the drive chambers 9a and 9b with the inlet port 2 via the cabana 12 while the other is connected to the discharge port. 4 is used for communication. Then, the inlet 16, the feedback port 17, and the outlet 18 of the cabana 12 are made to communicate with the inlet port 2, the outlet port 3 and the input port 19 of the switching valve 13 by the flow passage in the main body block 1, respectively, and further switched. By pushing the flow path switching push rods 22a, 22b provided in the valve 13 into the pressure boosting chambers 8a, 8b, the reciprocating pistons 6a, 6b press the push rods 22a, 22b near the end of the stroke. Communication between the ports of the switching valve 13 is switched so that the drive chambers 9a and 9b are alternately connected to the inlet port 2 and the discharge port 4 via the external flow paths 14a and 14b.

In the known pressure booster described above, switching of the switching valve can be performed smoothly by the reciprocating motion of the piston while the piston is driven at high speed. If the valve is driven at a low speed, when the switching valve reaches near the neutral position, the driving force of the piston becomes insufficient for switching the switching valve and the switching valve stops at the neutral position and cannot be restarted. Sometimes.

In order to solve this problem, a pressure increasing device having an improved switching valve has been improved in Japanese Utility Model Laid-Open Nos. 59-44203 and 62-108601 and in the inlet check valve. The pressure intensifiers provided with the above are respectively proposed in Japanese Utility Model Laid-Open No. 3-42075. Although these already proposed pressure intensifiers can obtain almost satisfactory results, it cannot be said that they cannot restart due to friction of the switching valve.

[0005]

[Problems to be solved by the device]

 The problem to be solved by the present invention is to provide a pressure booster capable of reliably restarting even when the supply fluid pressure decreases.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a discharge mechanism, in which the pressure booster described above discharges the secondary side fluid of the pressure booster chamber to the low pressure side before the piston pushes the push rod to switch the switching plate. It is characterized by having. Further, in order to solve the same problem, the discharge mechanism is characterized in that it is a discharge passage provided in a rod, a cylinder or a push rod. Further, in order to solve the same problem, the discharge mechanism is a discharge valve provided in the piston or the inlet check valve.

[0007]

[Action]

 When the pressure fluid is supplied to one of the drive chamber and the pressure boosting chamber, the piston is driven and the fluid in the other pressure boosting chamber is boosted and output. When the piston is driven near the end of the stroke, before the piston pushes the push rod to switch the switching valve, the secondary side fluid in the other booster chamber moves to the low pressure side by the discharge passage or discharge mechanism consisting of the discharge valve. Since the fluid is discharged, the fluid pressure in the other pressure boosting chamber decreases and the driving force of the piston becomes relatively large. Therefore, even when the driving force of the piston becomes small due to the decrease of the supplied fluid pressure, the piston presses the push rod with the large driving force, so that the communication between the ports of the switching valve can be reliably switched. So you can never restart.

[0008]

【Example】

 1 to 3 show a first embodiment of the present invention in which a rod 7 is provided with a discharge passage, which will be described later. It has the same structure as the booster. In the pressure booster having the above-described configuration, in FIG. 3, the pistons 6a, 6b and the rod 7 reach the left end in the figure, and the compressed air in the right pressure booster chamber 8a is boosted and output from the outlet port 3 is finished. By switching the switching valve 13 to the position shown in the drawing, the left drive chamber 9b is connected to the inlet port 2 via the switching valve 13 and the cabana 12, and at the same time, the right drive chamber 9a is switched between the switching valve 13 and the discharge port 4. It shows the state of being opened to the atmosphere through. Therefore, from this state, the pistons 6a and 6b are driven to the right by the combined force of the force acting on the piston 6b in the left drive chamber 9b and the force acting on the piston 6a in the right pressure increasing chamber 8a. The compressed air in the left pressure increasing chamber 8b is compressed and increased in pressure by this, and flows out from the outlet port 3 through the outlet check valve 11b. In this case, of course, in parallel with this, the line air as the primary pressure flows from the inlet port 2 into the pressure increasing chamber 8a from the inlet check valve 10a. In this way, when the pistons 6a, 6b reach the right side, the push rod 22b is pressed by the left piston 6b and the switching valve 13 is switched to the position opposite to that shown in the drawing, whereby the pistons 6a, 6b are left again. The line air increased in pressure in the pressure increasing chamber 8a on the right side is output from the outlet port 3 through the outlet check valve 11a, and by repeating this operation, the line air increased in pressure from both pressure increasing chambers 8a, 8b is continuous. Then, the output pressure is regulated by the cabana 12 to be substantially constant regardless of the increase / decrease in the load flow rate.

As shown in detail in FIG. 1, both ends of the main body block 1 of the first embodiment are closed by check valve bodies 32a and 32b, and cylinders are provided on the outer circumferences of the check valve bodies 32a and 32b via seals. The ends of the tubes 33a and 33b constituting 5A and 5B are fitted. The inlet check valve 10a provided in the check valve body 32a has a valve seat 35 that opens to a flow passage 34 (see also FIG. 3) communicating with the inlet port 2, and the valve body 38 that opens and closes the valve seat 35 is The check valve spring 37 biases the valve seat in the closing direction. Although not shown, the inlet check valve 10b provided in the check valve body 32b has the same structure as 10a.

The cabana 12 incorporated in the body block 1 acts on the lower surface of the diaphragm 50 and the urging force of the pressure adjusting spring 53 for setting the secondary pressure that acts on the upper surface of the diaphragm 50 that partitions the feedback chamber 46. The output pressure is adjusted to a set pressure depending on the magnitude of the acting force of the air pressure (secondary pressure) in the feedback chamber 46, and the set pressure of the cabana 12 is adjusted by rotating the cap 54 to move the pressure adjusting screw 56 forward and backward. This is done by adjusting the biasing force of the pressure spring 53. On the other hand, the switching valve 13 has push rods 22a and 22b whose outer peripheral surfaces are sealed by seal rings 23 and 23 and whose tip portions project into the pressure boosting chambers 8a and 8b. These push rods have strokes of pistons 6a and 6b. The spool 20 is pressed near the end to drive the spool 20, and the output ports 20a and 20b are switched between the input port 19 and the discharge ports 21a and 21b to communicate with each other. As shown in FIG. The ports 20a and 20b communicate with the outlet 18 of the cabana body 41 and one ends of the external flow paths 14a and 14b, and the discharge ports 21a and 21b communicate with the discharge port 4, respectively.

The rod 7 is hermetically sealed by the seal rings 26, 26 provided on the check valve bodies 32a, 32b, and axial discharge passages 27a, 27b constituting a discharge mechanism on the mounting side of the pistons 6a, 6b. (See FIG. 2) is formed, and the pressure boosting chambers 8a and 8b are input to the switching valve 12 through the outlet 18 of the governor 12 by the discharge passages 27a and 27b near the stroke ends of the pistons 6a and 6b. Connect to mouth 19. The axial length 1 of the discharge passages 27a and 27b is determined by the length L of the push rods 22a and 22b projecting into the pressure increasing chambers 8a and 8b in the switching position shown in FIG. 1 and the check valve bodies 32a and 32b. It is equal to or slightly larger than the sum of the distances a between the end faces and the seal rings 26, 26. The discharge passages 27a and 27b may have a small passage cross sectional area such as a V-shaped cross section.

In the first embodiment, when compressed air is supplied to the drive chamber 9b and the pressure boosting chamber 8a and the pistons 6a and 6b are driven near the end of the right movement stroke in the figure, the piston 6b pushes the push rod 22b. Since the pressure boosting chamber 8b communicates with the input port 19 of the switching valve 13 by the discharge passage 27b before pressing, the secondary side air pressure of the pressure boosting chamber 8b decreases and the driving force of the pistons 6a, 6b is reduced. Is relatively large, unlike the known pressure booster shown by the dotted line in FIG. 4, the piston that was driven at a substantially constant speed, as shown by the solid line in FIG. l (the length of the discharge passage in the axial direction) is increased. Therefore, even if the supply air pressure decreases and the piston driving force (push rod pressing force) decreases, the piston 6b presses the push rod 22b with the increased driving force and the switching valve 13 operates. Since the communication between the ports is reliably switched, the switching valve 13 does not stop at the neutral position and cannot be restarted. When the pistons 6a and 6b move to the left in FIGS. 1 and 2, it is the same as the case of moving to the right, and therefore detailed description is omitted.

FIG. 5 shows a second embodiment of the present invention in which the discharge passages 27a and 27b are provided in the tubes 33a and 33b of the cylinders 5A and 5B. The axial length 1 of these discharge passages is the push rod 22a, It is equal to or slightly larger than the sum of the above-mentioned protrusion length L of 22b and the distance b between the seal members 60, 60 of the pistons 6a, 6b and the end surface of the piston on the pressure increasing chamber side. In the second embodiment, the secondary air in the pressure boosting chambers 8a and 8b is discharged to the drive chambers 9a and 9b defined by the pistons 6a and 6b. Since the other structure and operation of the second embodiment are the same as those of the first embodiment, the same reference numerals are given to the main parts in the figure and the detailed description will be omitted.

FIG. 6 shows a third embodiment of the present invention in which the discharge passages 27a and 27b are provided in the push rods 22a and 22b, and the axial length l of these discharge passages 27a and 27b is The sum of the distance a ₁ between the check valve bodies 32a and 32b and the seal rings 23 and 23 is equal to or a little larger than the value obtained by subtracting the distance a ₂ between the spool 20 and the push rods 22a and 22b. In the third embodiment, when the pistons 6a, 6b press the push rods 22a, 22b, the secondary air in the pressure boosting chambers 8a, 8b passes to the outside through the discharge passages 27a, 27b and the discharge ports 21a, 21b. Is discharged. Since the other structure and operation of the third embodiment are the same as those of the first embodiment, the same reference numerals are given to the main parts in the drawing, and the detailed description will be omitted.

FIG. 7 shows a fourth embodiment of the present invention, in which the pistons 6a and 6b in this pressure boosting device discharge the secondary side air of the pressure boosting chambers 8a and 8b to the drive chambers 9a and 9b near the end of the stroke. Ejection valves 30a and 30b are provided. These discharge valves 30a and 30b are installed in a passage 62 that connects the pressure increasing chamber formed in the pistons 6a and 6b to the drive chamber, and a valve rod 64 having a seal ring 63 that closes the passage 62 from the drive chamber side. Has a tip protruding by a length l into the pressure increasing chambers 8a and 8b by the urging force of the spring 65. The protrusion length 1 is equal to or slightly longer than the sum of the length L and the crushing margin c of the seal rings 63, 63. In the fourth embodiment, when the pistons 6a and 6b approach the stroke ends, the valve rods 64 of the discharge valves 30a and 30b are pressed by the check valve bodies 32a and 32b to open the passage 62. The secondary air of 8b is discharged to the drive chambers 9a and 9b. Since the other structure and operation of the fourth embodiment are the same as those of the first embodiment, the same reference numerals are given to the main parts in the drawing, and the detailed description will be omitted.

FIG. 8 shows a fifth embodiment of the present invention, in which the inlet check valves 10a and 10b in this pressure booster are provided with the discharge valves 30a and 30b (30b is not shown) having the above-mentioned configuration. The projection length l of the valve rod 64 into the pressure boosting chambers 8a and 8b is equal to the length L or slightly longer. In the fifth embodiment, when the pistons 6a, 6b approach the stroke ends, the valve rods 64 of the discharge valves 30a, 30b are pressed to open the passage 62, so that the secondary side air in the pressure boosting chambers 8a, 8b is removed. It is discharged to the inlet port 2. Since the other structure and operation of the fifth embodiment are the same as those of the fourth embodiment, the same reference numerals are given to the main parts in the drawing, and the detailed description will be omitted.

[0017]

[Effect of the device]

 In the pressure booster of the present invention, before the piston pushes the push rod near the end of the stroke to switch the switching valve, the secondary side fluid in the pressure boosting chamber is discharged to the low pressure side by the discharge passage or the discharge mechanism including the discharge valve. By discharging and increasing the piston driving force relatively, the switching valve can be switched even when the supply fluid pressure drops and the piston driving force drops, so the pressure booster restarts. It can be surely prevented that it cannot be done.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a first embodiment.

FIG. 2 is a cross-sectional view showing the discharge of the secondary side fluid.

FIG. 3 is a configuration diagram of the same.

FIG. 4 is a diagram showing the relationship between piston stroke and time.

FIG. 5 is a longitudinal sectional view of a main part of the second embodiment.

FIG. 6 is a vertical cross-sectional view of a main part of the third embodiment.

FIG. 7 is a vertical cross-sectional view of a main part of the fourth embodiment.

FIG. 8 is a vertical cross-sectional view of the main parts of the fifth embodiment.

FIG. 9 is a configuration diagram of a known pressure booster.

[Explanation of symbols]

 1 Main body block 2 Inlet port 3 Outlet port 4 Exhaust port 5A, 5B Cylinder 6a, 6b Piston 7 Rod 8a, 8b Pressure boosting chamber 9a, 9b Drive chamber 10a, 10b Inlet check valve 11a, 11b Outlet check valve 13 Switching valve 19 Input Port 21a, 21b Discharge port 22a, 22b Push rod 27a, 27b Discharge passage 30a, 30b Discharge valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masashi Igarashi 4-2-2 Kinnodai, Taniwahara-mura, Tsukuba-gun, Ibaraki SMC Tsukuba Technology Center

Claims (6)

[Scope of utility model registration request] 1. A pair of cylinders sandwiching a main body block is provided, and a piston reciprocating in these cylinders is connected by a rod penetrating the main body block tightly. An inlet check valve that allows only the inflow of fluid to each pressure boosting chamber, an outlet check valve that allows only the outflow of fluid from each pressure booster chamber to the outlet port, and a push rod driven by the piston to drive it, In a pressure booster equipped with a switching valve that connects the drive chambers outside both pistons to an inlet port and an exhaust port so as to communicate with each other, before the pressure booster switches the switching valve by the piston pressing the push rod. A pressure boosting device comprising: a discharge mechanism for discharging the secondary side fluid of the pressure boosting chamber to a low pressure side. 2. The pressure booster according to claim 1, wherein the discharge mechanism is a discharge passage provided on the rod for communicating the pressure booster chamber with the input port of the switching valve. 3. The pressure booster according to claim 1, wherein the discharge mechanism is a discharge passage provided in the cylinder for communicating the pressure booster chamber with a drive chamber defined by a piston. 4. A discharge mechanism is provided on the push rod,
The pressure booster according to claim 1, wherein the pressure booster is a discharge passage for communicating with a discharge port of the switching valve. 5. The pressure booster according to claim 1, wherein the discharge mechanism is a discharge valve provided on the piston for communicating the pressure increase chamber with a drive chamber defined by the piston. 6. The pressure booster according to claim 1, wherein the discharge mechanism is provided in the inlet check valve, and is a discharge valve for communicating the pressure booster chamber with the inlet port.