JPS62188874A - Proportional solenoid valve control circuit - Google Patents

Abstract

PURPOSE:To simplify mechanism by controlling exciting current flowing to a solenoid so that it may be proportioned to the operation quantity of an adjust ment control part by means of the first and the second pulse generating circuits and a solenoid exciting circuit. CONSTITUTION:The second pulse generating circuit 32 is driven by a periodical pulse signals E1, E2 output by the first pulse generating circuit 31 and pulse signals F1, F2 proportioned to the operation quantity of an adjustment control part are output. Exciting current flowing to the solenoid of a proportional solenoid valve is controlled to turn on or off by these pulse signals F1, F2 and exciting current proportioned to the operation quantity of the adjustment control part of the solenoid valves 13, 14 flows. Therefore circuit formation can be simplified without needing servo mechanism and others.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a proportional solenoid valve control circuit that is capable of controlling the flow rate of a proportional solenoid valve according to the amount of operation of an adjusting operation section.

(Prior art) When controlling the flow rate of a boat using a proportional solenoid valve, conventionally a servo mechanism is provided and the resistance interposed between the solenoid of the proportional solenoid valve and the power source is varied according to the amount of operation of the adjustment operation section. The servo mechanism is operated so that the excitation current is proportional to the operation amount of the adjustment operation part, and the excitation current is passed through the solenoid of the proportional solenoid valve, thereby controlling the flow rate of the boat of the proportional solenoid valve. was.

(Problems to be Solved by the Invention) Therefore, in the conventional case, a servo mechanism and the like were required, and the proportional solenoid valve control circuit became extremely complicated, making manufacturing troublesome and increasing manufacturing costs.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a proportional solenoid valve control circuit that can control the flow rate of a proportional solenoid valve boat with a simple configuration.

(Means for Solving the Problem) The technical means of the present invention for solving this technical problem is a first pulse generation circuit 3 that outputs a pulse signal E with a constant period.
1, a second pulse generation circuit 32 that is driven by the pulse signal El of the first pulse generation circuit 31 and adjusts its pulse width so as to be proportional to the operation amount of the adjustment operation section; The present invention includes a solenoid excitation circuit 54 that is controlled on and off by the pulse signal F1 of the two-pulse generation circuit 32 and flows to the solenoid 13 of the proportional solenoid valve 11.

(Function) The second pulse generating circuit 32 is driven by the constant cycle pulse signals E, E2 outputted by the first pulse generating circuit 31, and the pulse generating circuit 32 generates a pulse proportional to the operation amount of the adjusting operation section. The signals F, , F2 are output, and the solenoid 13.1 of the proportional solenoid valve 11 is activated by the pulse signals F, , F2.
A substantially constant excitation current flowing through the solenoid 13 and 14 is controlled on and off, and an excitation current proportional to the operation amount of the adjustment operation section flows through the solenoids 13 and 14.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
In the figure, ■ is the tractor body, 2 is the front wheel, and 3 is the rear wheel. Reference numeral 4 denotes a hydraulic system for raising and lowering a working machine mounted at the rear of the tractor body 1. Reference numeral 5 designates a front loader, which includes a mounting frame 6 for mounting on the tractor body 1, a pair of left and right booms 7 pivotally connected to the mounting frame 6, a pair of left and right boom cylinders 8 for raising and lowering the boom 7, and a boom 7. Packet 9 pivotally attached to the tip of
and a packet cylinder 10 that operates the packet 9.

The boom cylinder 8 has a proportional solenoid valve 11 for boom control, and the packet cylinder 10 has a proportional solenoid valve 12 for packet control.
It can be controlled by These proportional solenoid valves 11, 12 are connected in series as shown in FIG. The boom control proportional solenoid valve 11 has a raising solenoid 13 and a lowering solenoid 14, and can be operated to any position from a neutral position to a raised position and a lowered position by energizing these solenoids 13 and 14. The proportional solenoid valve 12 for packet control has a scooping solenoid 15 and a dumping solenoid 16, and can be operated to any position from a neutral position to a scooping position and a dumping position by energizing these solenoids 15 and 16. And each excitation valve 11.
Ports 18 and 19 are respectively formed in 12 so as to send pressure oil from the pump P to the control valve device 17 side of the hydraulic device 4 when the pump P is in neutral. Reference numeral 20 denotes a floating electromagnetic valve for placing the boom cylinder 8 in a floating state, and can be freely switched to communicate or cut off the pipes 21 and 22 connected to each cylinder chamber of the boom cylinder 8 by energizing the solenoid 23. .

FIG. 1 shows a control circuit for a solenoid valve. Although FIG. 1 shows a control circuit for solenoids 13, 14, similar circuits are provided for each of the other solenoids 15, 16, and 23. In FIG. 1, 26 is a main switch, 27 is a NOT circuit, and 28 and 29 are NAND circuits.

31 is a first pulse generating circuit, 32 is a second pulse generating circuit, and 33 is a third pulse generating circuit, and each of these pulse generating circuits 31, 32, and 33 inputs the input to the input terminal A by monostable multivib break. It is configured to output from the output terminal Q a pulse signal that rises when the signal rises and falls at a time constant determined by the capacitors and resistors connected to the circuits 31, 32, and 33. When the NOT circuit 27 is outputting a high voltage, the first pulse generating circuit 3I is determined by the time constant of the capacitor CI and the resistor R2 as shown in FIG. 5(a) from the output terminal Q. In addition to outputting a pulse signal E1 of a constant frequency having a pulse width T1 as shown in FIG. The second pulse generation circuit 32 is
The pulse signal E1 of the first pulse generating circuit 31 is input to the input terminal A, and the pulse signal E1 from the output terminal Q as shown in FIG. It outputs a pulse signal F1 having a pulse width T2 determined by , and at the same time outputs a pulse signal F2, which is an inversion of the pulse signal F1, from the output end Φ as shown in FIG. 5(d). There is.

The variable resistance R is varied by sliding the slider 34. The third pulse generating circuit 33 inputs the pulse signal E1 of the first pulse generating circuit 31 to the input terminal A, and outputs the capacitor c3 from the output terminal Q to the rising edge of the pulse signal E1 as shown in FIG. 5(E). and a pulse signal G! with a pulse @T3 determined by resistor R3. At the same time, the output terminal Q outputs a pulse signal G2, which is an inversion of the pulse signal G1, as shown in FIG.

36.37 is a comparator that compares the output voltage from the slider 34 of the variable resistance R with the voltage of 1/2Voo, and
is located at the middle point of the variable resistor R from the neutral position n where the arrow a
When the slider 34 slides in the direction indicated by the arrow, the comparator 36 outputs a high voltage, and when the slider 34 slides from the neutral position n in the direction indicated by the arrow, the comparator 37 outputs a high voltage.

38.39 is an exclusive OR circuit, 40.41 is an AND circuit, and 42.43 is a field effect transistor, to which solenoids 13.14 are connected in series, and resistors 44.45 are connected. ing. 46.
47 is AND circuit 40.41 and field effect transistor 4
The comparator is interposed between the gate of the AND circuit 40 and 43, and is configured to intermittently drive the field effect transistors 42 and 43 by the pulse signal from the AND circuit 40 and 41. Also, one terminal of the comparator 46, 47 is connected to the resistor 44, 45.
The field effect transistor 42 is configured to input a voltage signal of
．． 43 and the resistor 44.45, and detects the change in the excitation current flowing through the solenoid 13.14.
Field effect transistor 42.4 so that it is constant
It is configured to control the current amplification value of No. 3. 24,
25 is a protection circuit for protecting the solenoid 13.14, and is composed of a diode 48.49, a capacitor 50.51, and a resistor 52.53. Exclusive OR circuit 3B
, 39 , AND circuit 40.41 , Comparator 36.37
and field effect transistors 42, 43, etc., the excitation current of a substantially constant value is controlled on/off by the pulse signals F, , F2 of the second pulse generation circuit 32, and the solenoid 13.
Solenoid excitation circuits 54 and 55 that flow through the solenoid 14 are configured.

FIG. 4 shows the adjustment operation section of the variable resistance R, 56 is an operation lever, and a spherical pivot 5 is attached to the top plate of the control box 57.
A grip portion 59 is provided at the upper end of this operating lever 56, and an actuating plate 60 is provided at the lower end. Reference numerals 61 and 62 denote sliding variable resistors, which are provided vertically in symmetrical positions in the control box 57 and are attached to the side wall of the control box 57 via mounting bolts 63 and 64. The resistors 61 and 62 have sliding bodies 65 and 66 that are vertically slidable.
．． 66 is biased up and down by coil springs 67 and 68 and pressed against the lower surface of the actuating plate 60. The resistance value of the resistor 6L62 changes as the sliding bodies 65 and 66 are moved in and out, and is connected via a lead wire of the circuit board 69, and the two constitute a variable resistor R. That is, if the operating lever 56 is set in the neutral position N facing vertically, the slider 34 in FIG. The slider 34 is configured to slide in the direction of the arrow a, and when it swings in the direction of the arrow B, the slider 34 slides in the direction indicated by the arrow.

In this embodiment, the pulse generating circuits 31, 32 .
33 connected to capacitors C,,c2. c3 has the same capacitance, and resistor R3 has a resistance value that is half the resistance value of resistor R1. Also, the total resistance of resistor R2 and variable resistor R (
The maximum resistance) is each set to a resistance value of ⅓ of the resistance R1. Therefore, the pulse width T3 of the pulse signal G1 of the third pulse generation circuit 33 is half the pulse width T1 of the pulse signal E1 of the first pulse generation circuit 31. Also the second
The pulse width T2 of the pulse signal F1 of the pulse generating circuit 32 is 172 times the pulse width T1 of the pulse signal E1 when the slider 34 is at the neutral position n, and from this state, the slider 34 is moved in the direction of arrow a. When the slider 34 is slid in the direction indicated by the arrow, the fall of the pulse signal F1 is delayed and the pulse width T2 is gradually increased. When the slider 34 is slid in the direction indicated by the arrow, the fall of the pulse signal F becomes faster and the pulse width T2 increases. gradually shrink.

Next, the operation will be explained with reference to the voltage waveform diagram in FIG. When the main switch 26 is turned on, the NAND circuit 29
A high voltage is input to the first pulse generation circuit 31 from the output terminal Q, and the first pulse generation circuit 31 outputs the pulse signal E1 from the output terminal Q and the pulse signal E2 from the output terminal Φ.

Also, the second pulse generation circuit 32 and the third pulse generation circuit 3
3 inputs the pulse signal E1 from the first pulse generation circuit 31, and the second pulse generation circuit 32 outputs the pulse signal F1 from the output terminal Q and the pulse signal F2 from the output terminal Φ. The third pulse generating circuit 33 outputs a pulse signal G from an output terminal Q and a pulse signal G2 from an output terminal Φ.

At this time, if the operating lever 56 is set to the neutral position N, the slider 34 is at the neutral position n, and the pulse signal F l + F 2 of the second pulse generation circuit 32 is transmitted to the third pulse generation circuit 33. The pulse signals G + and G 2 have the same pulse width, and no pulse signal is output from the exclusive OR circuits 38 and 39. Further, since the slider 34 is in the neutral position n, no signal is output from the comparators 36.37, and accordingly, the AND circuit 40.41 and the comparison circuit 46.47 do not output a pulse signal, and the solenoid 13. 14 maintains a demagnetized state.

When the operating lever 56 is swung from the neutral position N in the direction of arrow A, the slider 34 slides in the direction of arrow a. As a result, the second
The pulse width T2 of the pulse signal F1 of the pulse generation circuit 32 increases in proportion to the amount of operation of the operation lever 56, and therefore the pulse width T1 of the pulse signal Fl increases as compared to the third pulse generation circuit 33.
is larger than the pulse width T3 of the pulse signal G, and the exclusive OR circuit 38 outputs a pulse signal H1 as shown in FIG. 5(G). On the other hand, as the slider 34 slides in the direction of arrow a, the voltage signal from the slider 34 becomes low, so a signal is output from the comparator 36, and the gate of the AND circuit 40 is opened (.

As a result, a pulse signal H1 is output from the AND circuit 40,
The pulse signal H1 is input to the field effect transistor 42 via the comparator 46, and the transistor 42 repeats on/off operations in synchronization with the pulse signal H2. Therefore, an excitation current of a constant value flows intermittently to the raising solenoid 13, and the flow rate of the boat 18 of the proportional solenoid valve 11 is controlled according to the amount of operation of the operating lever 56 due to the dither effect. rises at a speed proportional to the amount of operation.

When the operating lever 56 is swung from the neutral position N in the direction of arrow B, the slider 34 slides in the direction indicated by the arrow, and as a result, the pulse width of the pulse signal F2 of the second pulse generation circuit 32 becomes large and the exclusive A pulse signal H2 is output from the logical OR circuit 39 as shown in FIG. 5(H). Further, by sliding the slider 34 in the direction indicated by the arrow, a signal is output from the comparator 37, and the gate of the AND circuit 41 is opened.

As a result, the field effect transistor 43 repeats the on/off operation in the same manner as described above, and a constant value of excitation current flows intermittently to the lowering solenoid 14, and due to the dither effect, the proportional solenoid valve 11 boats 18
The flow rate is controlled, and the boom 7 descends at a speed proportional to the amount of operation of the control lever 56.

6 and 7 show other embodiments, and in FIG. 6, the switch circuit is replaced with the field effect transistors 42, 43, and Darlington connected transistors 72, 73, 74 are used.
．． 75. In addition, Fig. 7 shows the solenoid protection circuit 24.25 using a Zener diode 76.7.
7.

By variably setting the values of resistors R1, R2, R3, and R, the pulse width and frequency of the pulse signals of the pulse generation circuits 31, 32, and 33 can be adjusted to best suit the performance and characteristics of the proportional solenoid valves 11 and 12. Can be adjusted to suit.

(Effects of the Invention) According to the present invention, the excitation current flowing through the solenoid 13 of the proportional solenoid valve 11 is adjusted by the operation amount of the operation unit by the first pulse generation circuit 31, the second pulse generation circuit 32, and the solenoid excitation circuit 54. Therefore, the flow rate of the boat 18 of the proportional solenoid valve 11 can be controlled with a very simple circuit configuration without the need for a servo mechanism, and the proportional solenoid valve control circuit can be manufactured very cheaply and easily. The practical effects are significant.

[Brief Description of the Drawings] Fig. 1 is an electric circuit diagram showing one embodiment of the present invention, Fig. 2 is a side view of the entire same, Fig. 3 is a hydraulic circuit diagram of the same, and Fig. 4 is an operational part of the same. A sectional view, FIG. 5 is a voltage waveform diagram for explaining the same operation, and FIGS. 6 and 7 are electric circuit diagrams showing other embodiments, respectively. 11... Proportional solenoid valve, 13... Raising solenoid,
14... Lowering solenoid, 31... First pulse generation circuit, 32... Second pulse generation circuit, 54.55.
...Solenoid excitation circuit, 56...operation lever, R.
...Variable resistance.

Claims (1)

[Claims] (1) A first pulse generation circuit 31 that outputs a pulse signal E_1 of a constant period, and is driven by the pulse signal E_1 of the first pulse generation circuit 31, and its pulse width is adjusted to be proportional to the operation amount of the adjustment operation section. a second pulse generating circuit 32 that generates a substantially constant excitation current;
A solenoid excitation circuit 5 that controls on/off by the pulse signal F_1 of No. 2 and supplies the flow to the solenoid 13 of the proportional solenoid valve 11.
4. A proportional solenoid valve control circuit comprising: