JPH0129281Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a flow rate amplification valve that is optimal for high water content hydraulic fluids, that is, low viscosity hydraulic fluids.

(Conventional Flow Amplification Valve) The conventional amplification valve shown in FIG. 1 includes spools 2 and 3 inside a valve body 1.

When the solenoid valve 4 is switched from the neutral position shown in the figure to the right position, the hydraulic fluid from the pump 5 flows through the inflow port 6 → passage 7 → solenoid valve 4 → passage 8 → pilot passage 9 to the rod of the cylinder 10. It flows into the side chamber 11.

Since a detection orifice 12 is provided in the pilot passage 9, when the pilot flow occurs as described above, this detection orifice 1
A differential pressure occurs around 2. This differential pressure flows into one pressure chamber 14 of the spool 3 through the damper orifice 13. When pilot pressure flows into the pressure chamber 14, the spool 3 descends as shown, and the communication hole 15 formed in the spool 3 communicates with the inflow port 6. Therefore, this inflow port 6
The hydraulic fluid flows into the rod side chamber 11 via the communication hole 15 → flow path 16 formed in the spool 3 → actuator flow path 17.

The return flow from the bottom side chamber 18 at this time is
It returns to the tank 23 via the pilot passage 19 → passage 20 → solenoid valve 4 → passage 21 → outflow port 22. Since the pilot passage 19 is provided with a detection orifice 24, when a flow occurs in the pilot passage 19, a pressure difference is generated before and after the detection orifice 24, and this pressure difference is applied to one pressure chamber 25 of the spool 2. The spool 2 is held in the illustrated state, and the communication hole 26 formed in the spool 2 is communicated with the outflow port 22.

Therefore, the return flow from the bottom side chamber 18 is
Actuator flow path 27 → flow path 28 formed in spool 2 → communication hole 26 → return to tank 23 via outflow port 22.

When the solenoid valve 4 is switched to the left side position in the drawing, the spool 2 is lowered and the spool 3 is raised, the working fluid of the pump 5 flows into the bottom chamber 18, and the return flow from the rod chamber 11 flows into the tank 23. leak.

Since the conventional flow rate amplification valve as described above uses the spools 2 and 3, it has the disadvantage that when a high water content hydraulic fluid is used, the amount of leakage from around the spool increases.

When the amount of leakage increases in this way, problems occur such as the pressure in the pressure chambers provided above and below the spool becoming unstable. to solve this problem,
For example, it is conceivable to reduce the diameter of the damper orifice described above, but in this case, the switching operation of the spool becomes slow and there are disadvantages such as generation of peak pressure.

As a means to solve this problem, it may be possible to use a poppet instead of the spool.

As a valve using such a poppet, for example, a logic valve A shown in FIG. 2 is conventionally known.

This logic valve A has check poppets a ₁ to _{a 4.}
This conventional logic valve does not have any amplification function.

(Purpose of the present invention) The purpose of this invention is to reduce the amount of leakage by using a plurality of poppets, and to provide a flow amplification valve having a flow amplification function.

(Embodiment of the present invention) In the embodiment shown in FIG. 3, a pilot passage 31a is connected to one port 30 of the switching valve 29, and a pilot passage 33a is connected to the other port 32.

And these pilot passages 31a, 33a
is branched into pilot passages 31b, 33b and pilot passages 31c, 33c, and joins actuator passages 34, 35 on the downstream side of pilot passages 31c, 33c.

Check valves 36, 37 and detection orifices 38, 39 are provided in the flow paths of the pilot passages 31b, 33b. The check valves 36 and 37 are connected to the detection orifice 3 from the switching valve 29.
The relationship is such that only flows in the 8 and 39 directions are allowed.

Also, check valves 40, 41 and detection orifices 42, 43 are provided in the flow paths of the pilot passages 31c, 33c. The check valves 40 and 41 are arranged to allow flow only from the detection orifices 42 and 43 toward the switching valve 29.

Pilot passages 31b and 33 as described above
Main poppets 44 and 45 are provided in parallel to b.

The main poppets 44, 45 consist of poppet parts 44a, 45a and spool parts 44b, 45b, and the poppet parts 44a, 45a are connected to the spring chamber 4.
6, 47, and the spool part 44
b, 45b are facing the pilot chambers 52, 53.

Spring 48, 49 in the spring chamber 46, 47
is interposed, and by the action of these springs 48 and 49,
Normally, the poppet portions are seated on the seat portions 50, 51 of the spring chambers 46, 47.

Main poppets 44, 45 made as above
The diameter of the spool portions 44b, 45b and the diameter of the seat portions 50, 51 are approximately equal, and the diameter of the poppet portions 44a, 45a and the spool portion 4 are approximately equal.
The working fluid from the pump P is introduced into the annular recesses 44c and 45c between the pumps 4b and 45b. The reason why they have the same diameter as described above is to prevent the main poppets 44, 45 from opening even if pressure from the pump P acts on the annular recesses 44c, 45c. However, the seat portion 5 should be adjusted so that the main poppet can be closed somewhat easily.
The diameter on the 0 and 51 sides is slightly smaller.

The pilot chambers 52 and 53 are connected to the check valve 3 via damper orifices 54 and 55.
6, 37 and the detection orifices 38, 39 are communicated with the pilot passages 31b, 33b.

Further, the spring chambers 46, 47 are connected to the actuator flow path 34,
It is connected to 35.

On the other hand, check poppets 58 and 59 are provided in parallel with the pilot passages 31c and 33c. The check poppets 58, 59 normally close the positions shown in the figure, that is, the seat portions 64, 65, by the action of springs 62, 63 provided in spring chambers 60, 61 at one end, and open the valves from the pilot passages 31c, 33c to the tank T. blocking the flow. When the pressure on the pilot passages 31c, 33c side overcomes the spring force of the springs 62, 63, the valve opens and the pilot passage 31
c, 33c are connected to tank T.

When the switching valve 29 is switched from the neutral position shown in the figure to the left side position in the figure, the working fluid from the pump P flows into the pilot passages 31a and 31b, and passes through the check valve 36 → detection orifice 38 → actuator flow passage 34. It flows into the bottom side chamber 67 of the cylinder 66.

When a flow is generated in the detection orifice 38 as described above, a pressure difference is generated before and after the detection orifice 38, and the pressure difference flows into the pilot chamber 52 via the damper orifice 54. When the pressure that has flowed into the pilot chamber 52 in this manner overcomes the spring force of the spring 48, the main poppet 44 moves against the spring 48, and the seat portion 5
Open 0.

When the seat portion 50 is opened, the working fluid from the pump P flows into the bottom side chamber 67 via the main orifice 56 → actuator channel 34 .

On the other hand, the return flow in the rod side chamber 68 of the cylinder 66 flows from the actuator passage 35 to the pilot passage 33c.
and a check valve 41. The return flow that has passed through the check valve 41 is then transferred to the pilot passage 3.
3a and returns to tank T via port 32.

In the process of the return flow flowing into the tank T as described above, it passes through the detection orifice 43, so a pressure difference is generated before and after the detection orifice 43, and this pressure difference acts on the check poppet 59 via the orifice 66. . When the pressure acting on the check poppet 59 overcomes the spring force of the spring 63, the check poppet 59 opens and directs the return flow from the rod side chamber 68 to the tank T.
Return to

Furthermore, when the switching valve 29 is switched from the neutral position shown in the figure to the right position, the main poppet 45 opens and the working fluid from the pump P flows into the rod side chamber 68, and the return flow from the bottom side chamber 67 passes through the check poppet 58. The flow then returns to the tank T, but the operational relationship at this time is the same as in the case described above in which the switching valve 29 was switched to the left position.

In this embodiment, a pair of main poppet and check poppet are provided, but depending on the purpose of use, it may be constructed with only one main poppet and a check poppet.

(Structure of the present invention) In this invention, a pilot passage leading to the pump via a switching valve is communicated with an actuator via a detection orifice, and a main poppet is connected in parallel to the pilot passage.
Moreover, one end of this main poppet faces the pilot chamber that leads the pressure upstream of the detection orifice, and the other end faces the spring chamber that leads the pressure downstream of the detection orifice, so that the main poppet can be adjusted according to the pressure difference between the two chambers. The main poppet is configured to open, and the pump and actuator are communicated through the main poppet, while a pilot passage separate from the pilot passage is provided in parallel with each other, and a detection orifice is formed in the pilot passage. This pilot passage is connected to the tank via the switching valve, and a check poppet is connected in parallel to the pilot passage, and one end of the check poppet is made to face the spring chamber, and the spring chamber is connected to the spring chamber. Connected to the downstream side of the detection orifice, and
The actuator is characterized in that it communicates with the tank via this check poppet.

With the above construction, by allowing a small amount of pilot flow to flow through the detection orifice, the main poppet and check poppet can jointly control a large flow rate.

(Effects of the present invention) This invention uses a poppet type as described above, so even when a high water content hydraulic fluid, that is, a low viscosity hydraulic fluid is used, the amount of leakage is reduced, and the response is good. Stable flow amplification is possible.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional valve, Figure 2 is a sectional view of a conventionally known logic valve, and Figure 3 is a circuit diagram of this invention. 31a to 31c, 33a to 33c... Pilot passage, 38, 39, 42, 43... Detection orifice, 44, 45... Main poppet, 58, 59
...Check poppet.

Claims (1)

[Scope of utility model registration request] A pilot passage leading to the pump via the switching valve is connected to the actuator via the detection orifice, and a main poppet is connected in parallel to the pilot passage, and one end of the main poppet is connected to the upstream side of the detection orifice. Place the other end facing the pilot chamber that leads the pressure.
The main poppet opens in response to the pressure difference between the two chambers, facing the spring chamber that guides the pressure downstream of the detection orifice, and communicates the pump with the actuator through the main poppet. Another pilot passage is provided, a detection orifice is provided in this pilot passage, and this another pilot passage is communicated with the tank via the switching valve, and
A check poppet is connected in parallel to this other pilot passage, and a spring chamber facing one end of this check poppet is connected to the downstream side of the detection orifice, and the actuator is connected to the tank via this check poppet. Flow rate amplification valve that communicates with each other.