JPH02142984A - Hydraulic control valve - Google Patents

Abstract

PURPOSE:To increase the extent of magnetic flux in the axial direction and make a startup of attraction into steepness as well as to prevent any rise in the attraction at a plunger stroke end from occurring by installing a projection which restricts the fitting of a plunger into a fixed core recess. CONSTITUTION:A solenoid proportional pressure control valve 1 is set to maximum setting pressure most proximate to pressure PS in a supply port 32, and an input current is taken into a coil 18 from a lead wire 19. If so, a plunger 7 makes a fixed iron core 9 generate attraction F7 as shown in full lines i1, i2, i3 conformed to input currents i1, i2 or i3, while a spool 4 keeps a position balanced in response to spring forces f15x, f16x conformed to a stroke (x). Then, the plunger 7 goes forward up to a position of a stroke end 7', at which a projection 41 of the plunger 7 is engaged with an engaged part 36 of a recess 35 and thereby its fitting value into this recess 35 is controlled. At this position, an edge 13 of the spool 4 is slightly overrun from an edge part 38 whereby a variable opening (e) is throttled to minimum, so that the control valve 1 is set to its minimum pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic control valve, and in particular to a small hydraulic control valve used in automobile engine control, preferably capable of obtaining an electromagnetic force proportional to an input current, The present invention relates to an electromagnetic proportional pressure control valve that can obtain a pressure according to the opening degree of the valve.

℃Prior Art] Electromagnetic proportional control valves used in general industrial hydraulic systems are well known. However, when trying to use this for automobiles, it was too large and too heavy, which caused problems in use.

Therefore, a small electromagnetic proportional pressure control valve is used, a small direct current electromagnet with a small suction force is used, and even though the suction force as a whole is small, for example, as shown in Fig. 6, regardless of the plunger stroke l' + 12
Attempts have been made to obtain a DC electromagnet that exhibits a flat attractive force, as shown by the dotted curve corresponding to ' + 13', and such attempts have also been made for electromagnets for electromagnetic proportional control valves used in general hydraulic systems. , for example, Jikko 52-5
There was one shown in FIG. 7 described in Japanese Patent No. 6449. A tapered taper (21) is provided on the outer periphery of the recess (20) of the fixed core to which the plunger (27) is attracted, and a guide for the plunger (27) that faces the outer periphery of the recess in the axial direction via an air gap (22). (28) The outer periphery of the end is tapered so that the plunger (27) connects to the fixed core (29)
When the plunger is attracted to the fixed iron core, the suction force at the start is increased, and the suction force is prevented from increasing rapidly when the gap (y) between the plunger and the fixed iron core becomes smaller. (26) is a spring. Rod (2) of plunger (27)
6) In the electromagnetic proportional pressure control valve, the spool of the pressure reducing valve is driven to obtain a pressure corresponding to the degree of opening of the valve, which is opened by an electromagnetic force proportional to the input current.

[Problem to be solved by the invention]

However, when such a DC electromagnet is used as an electromagnetic proportional pressure control valve for an automobile, the dotted line curve 11 in FIG.
'+1! As can be seen from '+Iff', the rising suction force F is still insufficient, and as the gap y becomes smaller, the suction force inevitably increases rapidly. Analyzing this in terms of the flow of magnetic flux (25) shown in Figure 7, when the current is applied, the magnetic flux (25) detours in the radial direction and passes through the fixed iron core (29) (53 fluxes), and when the current is applied, the magnetic flux (25) detours in the radial direction and passes through the fixed iron core (29). (27) toward the opposing fixed core (29), and the magnetic flux C1 that flows through the gap (y) to the fixed core (29), and only the magnetic flux C1 acts effectively as an attractive force.Then, the input current When becomes large, each magnetic flux (25) (b
, )(c,) respectively become larger.

The object of the present invention is to provide a hydraulic control valve having a DC electromagnet that increases the axial magnetic flux C to make the rise of the attractive force steep and prevents the strong attractive force from increasing at the end of the plunger stroke. be.

[Means to solve the problem]

Therefore, the present invention solves the problems of the conventional products described above by providing a hydraulic control valve as described in the claims.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.
Figure 1 shows a small electromagnetic proportional pressure control valve (1
) is a schematic cross-sectional view showing a pressure reducing valve section (10) and a DC electromagnet (11), both of which are fixed! (17)
and is further fixed to the automobile transmission by a mounting flange (not shown). The pressure reducing valve part (10) is fitted into the housing (3) so as to be slidable in the axial direction, and the spool (4) pressed by the spring (15) is connected to the pressure oil supply boat, that is, the S port (
Pressure oil at pressure PS from 32) is connected to the actuator port (A port) (31) while being throttled by the edge (13). The spool (4) is connected to the A boat (31) in the end oil chamber (30) via the internal communication path (d).
Pressure PA is introduced. (12) is a seal plate.

The DC electromagnet (11) includes a DC coil (18) fixed to the main body (14), a part of which is built inside the coil, and an extension part that cooperates with the main body (14) to form a magnetic path on the outside. (9')
a fixed iron core (9) having
When a current is input to 8) from the conductor (19), the fixed iron core (9) is guided by the guide (8) and movable in the axial direction so as to be attracted against the force of the spring (16). including a plunger (7). (6) is a plunger (
7) is in contact with the end of the spool (4).

In the present invention, an axial air gap (34) is interposed between the guide (8) and the fixed core (9), and one end of the plunger is inserted into the recess (35) of the fixed core (9). (7
When the plunger (7) is attracted to the fixed iron core (9), it can be inserted up to the dotted line position shown in '). In order to limit the amount of insertion of the plunger (7) into the recess (35), in the present invention, the plunger outer peripheral portion (37
) is provided with a protrusion (41) that can be engaged with the locking part (36) of the recess (35).

To explain the operation, in the state shown in the first diagram, the coil (1
8), the spool (4) is pushed by the springs (15) and (16) on both sides and is balanced in the position shown. The cross-sectional area of the spool (4) is A,
Set the pressure of the pressure oil at port A to PA, sp IJ 7g (15)
(16) If each force is fls + r + a, and ignoring fluid force and frictional force, the balance of forces acting on the spool (4) is as follows: Rightward force = f1. +PA-A-Leftward force f16, where fls + f16 is a function of the amount of movement (stroke) X of the spool (4), and according to the above formula, f1
%+f lk is selected.

In the state shown, the edge (13) of the spool forms a variable opening (e) with the inner peripheral edge (38) of the housing (3).
) shows the maximum opening, so the electromagnetic proportional pressure control valve (1
) is set to the highest set pressure, which is the pressure closest to the supply boat (32) pressure ps. And the coil (18
) has an input current from % (19) into the conductor, the plunger (7) causes the fixed core (9) to receive an input current (II+ tz
The solid line in Figure 6 (1++ 1z+ 1
The suction force F shown in 3) is generated, and the spool (4) generates a spring force f+sX+f,t corresponding to the stroke X.
A balanced position is maintained according to the relationship of the following formula according to hx.

F7 + f, 5x + P A ' A = f, b
41) engages with the locking part (36) of the recess (35),
The amount of insertion into the recess (35) is controlled. In this position, the edge (13) of the spool (4) slightly overlaps the edge (38), the variable opening (e) is minimized and the electromagnetic proportional pressure control valve (1) is set to the lowest pressure. be done.

Regarding the embodiment shown in FIGS. 2 and 3, which is different from the embodiment shown in FIG. The stroke X and suction force F of the plunger (7) shown are
It will be explained that the ll+ j2+ +3 curve showing the relationship between the

As shown in FIG. 2, when a current is input to the coil (18), magnetic flux (45) is generated as shown by the arrow.

In the present invention, in addition to 01b1 of the previous conventional product (Fig. 7), the protrusion (41) is passed through the recess (35) and the end face (36).
Since the line of magnetic force C1 is generated, the attractive force becomes larger at the time of rise. Then, as shown in Figure 3, the plunger (
When 7) strokes out and comes to position (7'),
There is a sufficient gap (48) between the recess (35) and the bottom (47).
) remains, and the plunger (7) outer periphery (37
) and the inner periphery of the recess (35) overlap, so the magnetic flux (46
) is bl plus b2. b3 and all flow in the radial direction from the plunger (7) toward the fixed iron core (9), so the suction force in the axial direction becomes smaller, and the solid line 11+ j in Figure 6
Like 2+13, the suction force became smaller at the end of the stroke.

However, in the position shown in Figure 2, a leakage of magnetic flux l, which did not occur in the conventional product shown in Figure 7, occurs between the end of the guide (8') and the protrusion (41), and this leakage of magnetic flux occurs. 1 is undesirable because it generates a magnetic force in the opposite direction to the magnetic flux CI+c2 and acts in a direction that moves the plunger (7) away from the fixed iron core (9).

This can be prevented by increasing the gap between the two, but this cannot be done with small electromagnets. Therefore, as shown in FIGS. 1 and 4, the end of the guide (8) on the side of the air gap (34) is tapered (42). In this way, in the position shown in the fourth figure, the magnetic flux leakage 12 is absorbed by the plunger (7), providing an electromagnetic proportional pressure control valve having a large DC electromagnet.

Figure 5 shows the S port (32) and A boat (31) in Figure 1.
) has a housing (3') in which the arrangement of the spool (3') is reversed and the spool (3') of FIG.
A pressure reducing valve part (10') with a spool (4') compatible with 4) is shown. The spool (4') is provided with an internal communication passage ((L''') including two radial passages.

In the above embodiments, an electromagnetic proportional pressure control valve has been described, but it goes without saying that the present invention can also be implemented with an electromagnetic proportional flow rate/directional hydraulic control valve, or an ordinary 0N10FF hydraulic control valve for automobiles or general industry. Nor.

More preferably, as shown in FIGS. 1 to 4, the protrusion (41) is a large-diameter annular portion that protrudes on the outer circumference (37) of the plunger (7), and the end surface of the recess (36) (
36) has a flat end surface, which means that the magnetic flux C! desirable for strengthening

By increasing the magnetic flux C of The present invention provides a hydraulic control valve with a direct current electromagnet.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an electromagnetic proportional pressure control valve according to an embodiment of the present invention, and FIGS. 2 and 3 are sectional views of main parts of a DC electromagnet of an embodiment hydraulic control valve different from FIG. The positions at the start of operation and at the end of the stroke are shown respectively. Figure 4 is a sectional view of the main parts explaining the operation of the DC electromagnet in Figure 1,
The figure is a sectional view of the main parts of the pressure reducing valve, which is different from that shown in Figure 1. Figure 6 is a graph showing the relationship between the plunge and ear strokes and the suction force. It is a sectional view of the main part.

Claims (4)

[Claims] (1) A projection is provided on the outer periphery of the plunger that can be fitted into a recess of a fixed core that is guided by a guide and arranged with an air gap in the axial direction between the guide and the recess. 1. A hydraulic control valve comprising a direct current electromagnet that engages with the plunger to limit the amount of engagement of the plunger into the recess. (2) The hydraulic control valve according to claim 1, wherein the locking portion of the recess is a flat end surface on the air gap side, and the protrusion is a large-diameter annular portion protruding from the outer circumference of the plunger. (3) The hydraulic control valve according to claim 1 or 2, wherein the air gap side end of the guide is tapered. (4) The hydraulic control valve according to claim 1, 2 or 3, wherein the hydraulic control valve is an electromagnetic proportional pressure control valve.