CN102536942B - Throttle loop - Google Patents

Abstract

The invention discloses a throttle loop. The throttle loop comprises a first working port (A), a second working port (B), a directional flow control valve (1) and four switch valves (21, 22, 23, 24), wherein the first working port (A) is communicated with the pressure oil port (1P) of the directional flow control valve (1); the four switch valves (21, 22, 23, 24) are connected between the first working port (A) and the first working oil port (1A) of the directional flow control valve (1), between the first working oil port (1A) and the second working oil port (1B) of the directional flow control valve (1), between the second working oil port (1B) and the second working port (B) of the directional flow control valve (1) and between the second working port (B) and the oil return port (1T) of the directional flow control valve (1) in series respectively. The through-current capability of the throttle loop can be regulated, so that the throttle loop is applicable for a relatively wide pressure regulation range.

Description

Throttle circuit

Technical field

The present invention relates to Hydraulic Field, particularly, relate to a kind of throttle circuit.

Background technique

Throttle valve is a kind of valve of extensive use in hydraulic system, for example can be in hydraulic pilot valve system, as the loading loop of pilot system, for regulating the outlet pressure of tested liquid pressure valve.The throttling action that throttle valve produces in the time of can utilizing fluid to pass through restriction, regulates the pressure in its loop, place.When adopting the throttle valve adjustment circuit pressure of determining latus rectum, for too small test flow, pressure regulates too sensitive and is difficult to accurate control, for excessive test flow, even if restriction is opened completely, fluid still has larger throttling action by restriction, and pressure cannot further be turned down, loses pressure adjusting function.Carry out more specific description below.

The fluid that flows through the restriction of throttle valve meets flow formula:

$q=C_{d}A\sqrt{\frac{2}{\mathrm{\ρ}}\mathrm{\Δp}}---\left(1\right)$

In formula: the flow of the q-restriction of flowing through, C _d-flow coefficient, A-restriction flow area, ρ-fluid density, pressure reduction before and after Δ p-restriction

C wherein _dwith ρ be constant, restriction flow area A is the function of throttle valve core displacement x, the sliding valve style throttle valve that is for example rectangle for restriction, restriction flow area A is expressed as following formula:

A＝w×x (2)

In formula: w-area gradient

Therefore, formula (1) is converted, obtains:

$\mathrm{\Δp}=\frac{\mathrm{\ρ}}{2}{\left(\frac{q}{c_{d}w}\right)}^2\·\frac{1}{x^2}=\frac{K}{w^2}\·\frac{1}{x^2}---\left(3\right)$

In formula: $K=\frac{\mathrm{\ρ}}{2}{\left(\frac{q}{C_d}\right)}^2$

For the throttle valve of determining latus rectum size, w is constant, and under constant test flow q, K is constant, regulates throttle valve core displacement x can change the valve pressure drop Δ p at throttle valve two ends.By formula (3), can be obtained:

When x reduces, A reduces, and Δ p increases until default pressure P _s, the pressure maximum that therefore can set up for example, is determined by system (relief valve in system).

When x increases, A increases, and Δ p reduces until x increases to maximum value x _max, therefore, the pressure minimum that can set up is determined by the latus rectum size of throttle valve.

Existing throttle valve has following shortcoming:

First, regulating pressure more to approach default pressure P _stime, pressure adjustment process will be sensitiveer and to cause controlling difficulty higher, and derivation is as follows:

As Δ p=P _stime, corresponding throttle valve core displacement x=x _s, wherein, x _srepresentation is:

$x_s=\sqrt{\frac{K}{P_s}}\·\frac{1}{w}---\left(4\right)$

By formula (3) to x differentiate:

$\frac{\mathrm{d\Δp}}{\mathrm{dx}}=\frac{-2K}{w^2}\·\frac{1}{x^3}---\left(5\right)$

At x=x _stime, by the value of formula (4) bring into formula (3) derivative value be

${\frac{\mathrm{d\Δp}}{\mathrm{dx}}|}_{x=x_s}=\frac{-2}{\sqrt{K}{P}_s^{\frac{2}{3}}}\·w^{\frac{2}{3}}---\left(6\right)$

By formula (6), selected throttle valve latus rectum is larger, and w is larger, and near the derivative value while adjusting to pressure maximum is also just larger, and this shows that pressure is larger to the gain of spool travel this moment, and excessive gain will cause adjustment too sensitive, be unfavorable for the stability of a system.Therefore,, near maximum adjustable pressure, the throttle valve of little latus rectum can obtain than the better regulating effect of large latus rectum.

Secondly, x is increased, regulate pressure to change to reducing trend, when x reaches maximum value x _maxtime, on-load pressure reaches minimum value Δ p=P _min, its representation is:

$P_{\min }=\frac{\mathrm{\ρ}}{2}{\left(\frac{q}{C_{d}w}\right)}^2\·\frac{1}{x_{\max }^2}=\frac{K}{w^2}\·\frac{1}{x_{\max }^2}---\left(7\right)$

By formula (7), selected throttling latus rectum is larger, and w is larger, minimum adjustable pressure P _minless, therefore, the throttle valve of large latus rectum can obtain less minimum adjustable pressure, expands pressure regulation range.

By above-mentioned analysis, can be obtained, when test flow one timing, in whole pressure regulation range, there is contradiction in the demand for throttle valve latus rectum: near maximum adjustable pressure, expectation throttle valve latus rectum is the smaller the better, yet, near minimum adjustable pressure, choose large latus rectum throttle valve more favourable.

Summary of the invention

The throttle circuit that the object of this invention is to provide a kind of alternative existing throttle valve, the through-current capability of this throttle circuit can regulate, thereby adapts to wider pressure regulation range.

To achieve these goals, the invention provides a kind of throttle circuit, wherein, this throttle circuit comprises the first working port, the second working port, directional flow control valve and four switch valves, described the first working port is communicated with the pressure hydraulic fluid port of directional flow control valve, described four switch valves are serially connected in respectively between the first working port and the first actuator port of directional flow control valve, between first actuator port and the second actuator port of directional flow control valve, between second actuator port and the second working port of directional flow control valve, and second between working port and the oil return inlet T of directional flow control valve, wherein, described directional flow control valve is proportional reversing valve.

Preferably, described proportional reversing valve replaces with servovalve.

Preferably, described directional flow control valve is 3-position 4-way proportional reversing valve.

Preferably, described directional flow control valve is solenoid-operated proportional selector valve.

Preferably, described four switch valves at least comprise a logical valve.

Preferably, described four switch valves at least comprise a selector valve.

Preferably, described four switch valves at least comprise a stop valve.

Preferably, described four switch valves are four logical valves, and two working holes of these four logical valves are communicated with the first actuator port of described the first working port and described directional flow control valve respectively, are communicated with the first actuator port and second actuator port of described directional flow control valve, with the second actuator port of described directional flow control valve with described the second working port is communicated with and be communicated with the return opening of described the second working port and described directional flow control valve.

Preferably, described four logical valves are electric-controlled type logical valve.

Preferably, described electric-controlled type logical valve comprises main valve body and solenoid directional control valve, and an actuator port of this solenoid directional control valve is communicated with the control mouth of described main valve body.

Preferably, the solenoid directional control valve of described electric-controlled type logical valve is two-position four-way solenoid directional control valve, and an actuator port of this two-position four-way solenoid directional control valve is communicated with the control mouth of described main valve body, another actuator port cut-off.

Preferably, described electric-controlled type logical valve also comprises shuttle valve, and the pressure hydraulic fluid port of described two-position four-way solenoid directional control valve is communicated with the oil circuit that two working holes of described main valve body are communicated with respectively by described shuttle valve.

By technique scheme, directional flow control valve can either be controlled fluid commutation, can regulate valve port opening by controlling valve element position again.Therefore, directional flow control valve can be regarded as the combination of the proportional throttle valve of two spool interlocks, each proportional throttle valve can be regarded as a variable liquid resistance, therefore by controlling four switch valves, carry out the outside oil circuit of switching direction flow control valve, and by controlling party, to flow control valve itself, control fluid and commutate, just can realize series, parallel, simply connected or the short circuit of two variable liquid resistances, thereby regulate the first working port of throttle circuit and the through-current capability between the second working port, thereby adapt to wider pressure regulation range.

Other features and advantages of the present invention partly in detail are described the embodiment subsequently.

Accompanying drawing explanation

Accompanying drawing is to be used to provide a further understanding of the present invention, and forms a part for specification, is used from explanation the present invention, but is not construed as limiting the invention with embodiment one below.In the accompanying drawings:

Fig. 1 is according to the schematic block diagram of the throttle circuit of one embodiment of the present invention;

Fig. 2 to Fig. 5 is respectively the schematic block diagram of short circuit state, simply connected state, state in parallel and the series connection of throttle circuit as shown in Figure 1;

Fig. 6 is according to the schematic block diagram of the throttle circuit of another embodiment of the invention;

Fig. 7 is according to the schematic block diagram of the throttle circuit of another mode of execution of the present invention.

Description of reference numerals

A the first working port; B the second working port;

1 directional flow control valve; 21,, 22,23,24 switch valves;

1P pressure hydraulic fluid port; 1T return opening;

1A the first actuator port; 1B the second actuator port;

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is elaborated.Should be understood that, embodiment described herein only, for description and interpretation the present invention, is not limited to the present invention.

As shown in Figure 1, according to one embodiment of the present invention, provide a kind of throttle circuit, wherein, this throttle circuit comprises the first working port A, the second working port B, directional flow control valve 1 and four switch valves 21, 22, 23, 24, described the first working port A is communicated with the pressure hydraulic fluid port 1P of directional flow control valve 1, described four switch valves 21, 22, 23, 24 are serially connected in respectively between the first actuator port 1A of the first working port A and directional flow control valve 1, between the first actuator port 1A and the second actuator port 1B of directional flow control valve 1, between the second actuator port 1B and the second working port B of directional flow control valve 1, and second between working port B and the return opening 1T of directional flow control valve 1.

By technique scheme, directional flow control valve 1 can either be controlled fluid commutation, can regulate valve port opening by controlling valve element position again.More specifically, take proportional reversing valve as example, proportional reversing valve can comprise two working positions, each working position has two passages, therein during a working position, the pressure hydraulic fluid port of this proportional reversing valve is communicated with a passage of formation with one of them actuator port (being called the first actuator port), return opening is communicated with another passage of formation with another actuator port (being called the second actuator port); When another working position, the pressure hydraulic fluid port of proportional reversing valve is communicated with a passage of formation with the second actuator port, and return opening is communicated with another passage of formation with the first actuator port.Proportional reversing valve is controlled fluid by switching between two working positions and is commutated.And on each passage, be provided with the restriction can ratio regulating, and by controlling the size of the restriction of valve element position on can two passages of synchronization regulation, thereby adjusting valve port opening.Each passage with restriction can be regarded as a proportional throttle valve.Therefore, directional flow control valve 1 can be regarded as two proportional throttle valve R1 of spool interlock, the combination of R2, each proportional throttle valve can be regarded as a variable liquid resistance, therefore by controlling four switch valves 2, carry out the outside oil circuit of switching direction flow control valve 1, and by controlling party, to flow control valve 1, itself control fluid and commutate, just can realize two variable liquid resistance R1, the series connection of R2, in parallel, simply connected or short circuit, thereby regulate the first working port A of throttle circuit and the through-current capability between the second working port B, thereby adapt to wider pressure regulation range.

Above-mentioned directional flow control valve 1 can adopt the various suitable valve version that can control fluid commutation and adjusting valve port opening, in three kinds of mode of executions as shown in Fig. 1, Fig. 6 and Fig. 7, this direction flow control valve 1 is proportional reversing valve, more specifically, be the 3-position 4-way proportional reversing valve of O type Median Function.Preferably, this flow control valve 1 is solenoid-operated proportional selector valve, thereby conveniently above-mentioned throttle circuit is controlled automatically.Certainly, this flow control valve 1 can be also proportional reversing valve or the pneumatic proportional selector valve of surging.In addition, this direction flow control valve 1 can be also the more excellent servovalve of control performance.

Above-mentioned switch valve 21,22,23,24 can be any valve that can oil circuit control conduction and cut-off, and for example, in the mode of execution shown in Fig. 1, switch valve 21,22,23,24 is logical valve.Logical valve, also referred to as cartridge valve, generally includes two actuator ports and a control mouthful, when control mouthful has action of hydraulic force, between two actuator ports, is not communicated with the cut-off of place oil circuit; When control mouthful does not have action of hydraulic force, between two working holes, be communicated with place oil circuit conducting.Two working holes of four logical valves are communicated with the first actuator port 1A of described the first working port A and described directional flow control valve 1 respectively, are communicated with the first actuator port 1A and the second actuator port 1B of described directional flow control valve 1, are communicated with and are communicated with the return opening 1T of described the second working port B and described directional flow control valve 1 with the second actuator port 1B and the described second working port B of described directional flow control valve 1.

Logical valve can adopt various suitable control modes, and for example logical valve can be electric-controlled type logical valve as shown in Figure 1.For example, as shown in Figure 1, electric-controlled type logical valve comprises main valve body and solenoid directional control valve, and an actuator port of this solenoid directional control valve is communicated with the control mouth of described main valve body.That is to say, the control mouth of whether controlling at logical valve by built-in solenoid directional control valve applies hydraulic coupling.The solenoid directional control valve of described electric-controlled type logical valve can be the solenoid directional control valve of various appropriate formats, for example as shown in Figure 1, it can be two-position four-way solenoid directional control valve, an actuator port of this two-position four-way solenoid directional control valve is communicated with the control mouth of described main valve body, another actuator port cut-off (blocking by plug).The return opening of this two-position four-way solenoid directional control valve is communicated with fuel tank directly or indirectly, and the pressure oil circuit that the pressure hydraulic fluid port of this two-position four-way solenoid directional control valve can adopt various suitable modes and fuel-economizing loop or apply the hydraulic system in this fuel-economizing loop is communicated with.For example as shown in Figure 1, described electric-controlled type logical valve also comprises shuttle valve, and the pressure hydraulic fluid port of described two-position four-way solenoid directional control valve is communicated with the oil circuit that two working holes of described main valve body are communicated with respectively by described shuttle valve.More particularly, the oil circuit that two entrances of shuttle valve are communicated with two working holes of described main valve body is respectively communicated with, and the outlet of shuttle valve is communicated with the pressure hydraulic fluid port of two-position four-way solenoid directional control valve.That is to say, the oil circuit that the pressure hydraulic fluid port of described two-position four-way solenoid directional control valve is optionally communicated with two working holes of the main valve body of this logical valve by shuttle valve is communicated with, thereby provides pressure oil for two-position four-way solenoid directional control valve.

As shown in Figure 1, logical valve obtains when electric at the electromagnet of its solenoid directional control valve, and this solenoid directional control valve is positioned at left position, and the control mouth of logical valve has action of hydraulic force, thus the cut-off of place oil circuit; Logical valve is when the electromagnet dead electricity of its solenoid directional control valve, and this solenoid directional control valve is positioned at right position, and the control mouth of logical valve is communicated with fuel tank, there is no action of hydraulic force, thus place oil circuit conducting.Specifically, as shown in Figure 1, in four logical valves, see from left to right, two working holes of first logical valve are communicated with the first actuator port 1A of described the first working port A and directional flow control valve 1 respectively, two working holes of second logical valve are communicated with the first actuator port 1A and the second actuator port 1B of directional flow control valve 1 respectively, two working holes of the 3rd logical valve are communicated with the second actuator port 1B and the second working port B of directional flow control valve 1 respectively, two working holes of the 4th logical valve are communicated with the second working port B and the return opening 1T of directional flow control valve 1 respectively.

In the mode of execution shown in Fig. 6, switch valve 21,22,23,24 is selector valve, can switch to make oil circuit conduction and cut-off by the position of this selector valve.More specifically, in mode of execution as shown in Figure 6, this switch valve 21,22,23,24 is two-position four-way solenoid directional control valve, and the pressure hydraulic fluid port of this solenoid directional control valve and one of them actuator port are connected on oil circuit, and return opening and another actuator port end by plug.When this solenoid directional control valve obtains when electric, between the pressure hydraulic fluid port of this solenoid directional control valve and actuator port, be not communicated with, so the cut-off of place oil circuit; When this solenoid directional control valve dead electricity, between the pressure hydraulic fluid port of this solenoid directional control valve and actuator port, be communicated with, so place oil circuit conducting.The automation that switch valve 21,22,23,24 adopts logical valve or solenoid directional control valve can realize the through-current capability of throttle circuit is controlled.In the mode of execution shown in Fig. 7, switch valve 21,22,23,24 is stop valve, and stop valve is a kind of manually operated opening/shutting valve, by manually-operable stop valve, makes oil circuit conduction and cut-off, although automaticity is not high, cost is lower.

The throttle circuit shown in Fig. 1 take below as example, specifically describe short circuit state, simply connected state, state in parallel and the series connection of this throttle circuit.

Table 1 show throttle circuit as shown in Figure 1 four kinds of state of switch valves 21,22,23,24 as shown in Figures 2 to 5 power failure state.

Table 1 throttle circuit as shown in Figure 1 four kinds of state of switch valves 21,22,23,24 as shown in Figures 2 to 5 power failure state

As shown in Figure 2, now no matter directional flow control valve 1 is in meta, left position or right position, two variable liquid resistance R1, R2 of directional flow control valve 1, in short circuit state, do not have liquid resistance between the first working port A of throttle circuit and the second working port B, do not play throttling action.

As shown in Figure 3, make directional flow control valve 1 in left position, between the first working port A of throttle circuit and the second working port B, only have one of them variable liquid resistance R1 to work, the liquid resistance size of therefore variable liquid resistance R1 changes with spool travel x, total the through-current capability of throttle circuit is determined by R1 restriction.

As shown in Figure 4, make directional flow control valve 1 in left position, two variable liquid resistance R1, R2 between the first working port A of throttle circuit and the second working port B are parallel with one another, the liquid resistance size of two variable liquid resistance R1, R2 changes with spool travel x simultaneously, and coupling is symmetrical, so total through-current capability of throttle circuit is the twice of single variable liquid resistance R1.

As shown in Figure 5, make directional flow control valve 1 in left position or right position, the first working port A of throttle circuit connects mutually with two variable liquid resistance R1, R2 between the second working port B, the liquid resistance size of two variable liquid resistance R1, R2 changes with spool travel x simultaneously, and coupling is symmetrical, so total through-current capability of throttle circuit is single variable liquid resistance R1 half.

In sum, by switch valve 21,22,23,24 is carried out to combination energising with good conditionsi, and the switching to direction flow control valve 1 own, two of directional flow control valve 1 variable liquid can be hindered to R1 and R2 in short circuit, simply connected, four kinds of states of parallel connection and serial connection, during short circuit state, the first working port A is directly connected with the second working port B and without directional flow control valve 1, it cannot carry out pressure flow adjusting, with respect to without throttle valve state.And under simply connected, parallel connection and serial connection state, throttle circuit has respectively three kinds of through-current capabilities, according to aforementioned analysis, wherein the through-current capability of state in parallel is the twice of simply connected state, and the through-current capability of series connection is half of simply connected state.Therefore, adopt this throttle circuit, be equivalent to substitute the throttle valve of large, medium and small three kinds of latus rectums and without throttle valve state, according to pressure controlled actual requirement, by switching valve 21,22,23,24 and directional flow control valve 1, can realize respectively large, medium and small three kinds of through-current capabilities of throttle circuit, thereby adapt to wider pressure regulation range.In whole pressure regulation range, near maximum adjustable pressure, throttle circuit can be switched to little through-current capability state (series connection), can obtain comparatively suitable pressure and regulate gain, be unlikely to excessive and cause adjusting too sensitive, improved the stability that system is controlled.Near minimum adjustable pressure, throttle circuit can be switched to large through-current capability state (state in parallel), obtain less minimum adjustable pressure, expand regulation range.And for marginal force value, throttle circuit can be switched to the medium through-current capability state (simply connected state) that adopts.In above-mentioned handoff procedure, need not change element, need not reclosing pipeline, easy switching, it is efficiently convenient to operate.

Above-mentioned throttle circuit can substitute throttle valve and be widely used in Hydraulic Field, for example can be for hydraulic pilot valve system.

Below describe by reference to the accompanying drawings the preferred embodiment of the present invention in detail; but; the present invention is not limited to the detail in above-mentioned mode of execution; within the scope of technical conceive of the present invention; can carry out multiple simple variant to technological scheme of the present invention, these simple variant all belong to protection scope of the present invention.

It should be noted that in addition each the concrete technical characteristics described in above-mentioned embodiment, in reconcilable situation, can combine by any suitable mode.For fear of unnecessary repetition, the present invention is to the explanation no longer separately of various possible compound modes.

In addition, between various mode of execution of the present invention, also can carry out combination in any, as long as it is without prejudice to thought of the present invention, it should be considered as content disclosed in this invention equally.

Claims (12)

1. a throttle circuit, this throttle circuit comprises the first working port (A), the second working port (B), directional flow control valve (1) and four switch valves (21, 22, 23, 24), it is characterized in that, described the first working port (A) is communicated with the pressure hydraulic fluid port (1P) of directional flow control valve (1), described four switch valves (21, 22, 23, 24) be serially connected in respectively between the first working port (A) and first actuator port (1A) of directional flow control valve (1), between first actuator port (1A) and the second actuator port (1B) of directional flow control valve (1), between second actuator port (1B) and the second working port (B) of directional flow control valve (1), and second between working port (B) and the return opening (1T) of directional flow control valve (1), wherein, described directional flow control valve (1) is proportional reversing valve.

2. throttle circuit according to claim 1, is characterized in that, described proportional reversing valve replaces with servovalve.

3. throttle circuit according to claim 1, is characterized in that, described directional flow control valve (1) is the 3-position 4-way proportional reversing valve of O type Median Function.

4. throttle circuit according to claim 1, is characterized in that, described directional flow control valve (1) is solenoid-operated proportional selector valve.

5. according to the throttle circuit described in any one in claim 1 to 4, it is characterized in that, described four switch valves (21,22,23,24) at least comprise a logical valve.

6. according to the throttle circuit described in any one in claim 1 to 4, it is characterized in that, described four switch valves (21,22,23,24) at least comprise a selector valve.

7. according to the throttle circuit described in any one in claim 1 to 4, it is characterized in that, described four switch valves (21,22,23,24) at least comprise a stop valve.

8. throttle circuit according to claim 5, it is characterized in that, described four switch valves (21, 22, 23, 24) be four logical valves, two working holes of these four logical valves are communicated with first actuator port (1A) of described the first working port (A) and described directional flow control valve (1) respectively, be communicated with the first actuator port (1A) and second actuator port (1B) of described directional flow control valve (1), be communicated with the second actuator port (1B) and described second working port (B) of described directional flow control valve (1), and be communicated with the return opening (1T) of described the second working port (B) and described directional flow control valve (1).

9. throttle circuit according to claim 8, is characterized in that, described four logical valves are electric-controlled type logical valve.

10. throttle circuit according to claim 9, is characterized in that, described electric-controlled type logical valve comprises main valve body and solenoid directional control valve, and an actuator port of this solenoid directional control valve is communicated with the control mouth of described main valve body.

11. throttle circuits according to claim 10, it is characterized in that, the solenoid directional control valve of described electric-controlled type logical valve is two-position four-way solenoid directional control valve, and an actuator port of this two-position four-way solenoid directional control valve is communicated with the control mouth of described main valve body, another actuator port cut-off.

12. throttle circuits according to claim 11, it is characterized in that, described electric-controlled type logical valve also comprises shuttle valve, and the pressure hydraulic fluid port of described two-position four-way solenoid directional control valve is communicated with the oil circuit that two working holes of described main valve body are communicated with respectively by described shuttle valve.