JP2001126920A - Direct-acting type solenoid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of a direct-acting type solenoid which is used in an electromagnetic valve of a brake pressure control valve. SOLUTION: This solenoid is provided with a coil 8, accommodated in a case 6, a core 14 where one end portion is inserted in the inner peripheral part of the coil 8 and the other end portion is fixed to the case 6, a plate 18 fixing the coil 8 to the case 6, and a plunger 16 which is slidably inserted in the inner peripheral part of the coil 8 and whose tip surface is opposite to one end surface of the core 14. A columnar protruding part 14b is formed on an end surface 14a of the core 14. A recessed part 16c for accepting the protruding part 24b is formed on an end surface of a plunger 16. An annular trench 14c is formed on the outer peripheral surface of the protruding part 14b. As to the electromagnetic valve of a brake pressure control valve, the amount of opening of a valve mechanism 36 is about 1.2 mm, and the stroke of the plunger 16 is large. In a region where a magnetic gap G1 is large such as this, the magnetic attraction force is larger, and moreover the lowest operation voltage is smaller than the conventional solenoid 2, so that miniaturization is possible as compared with the solenoid 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct acting solenoid used for an electromagnetic valve, and more particularly to a direct acting solenoid suitable for a brake pressure control valve and the like.

[0002]

2. Description of the Related Art A brake operating device provided with a hill start assist device provided on a large vehicle such as a truck or a trailer usually sets a brake valve attached to the brake pedal to a supply mode when a brake pedal is depressed. The compressed air in the air tank is supplied to the input port of the brake pressure control valve via the brake valve, and is further supplied to the brake actuator from the output port of the brake pressure control valve. The hydraulic pressure generated by the brake actuator acts on the wheel cylinder to perform a brake operation. Also, when you release the brake pedal,
When the brake valve is in the exhaust mode, the compressed air in the brake actuator is discharged to the outside through the exhaust port of the brake valve via the brake pressure control valve, and the brake is released.

In the brake operating device, when the brake pedal is continuously depressed for a certain period of time, for example, when the vehicle is stopped on an uphill road, the controller senses and activates an electromagnetic valve incorporated in the brake pressure control valve, so that an internal brake actuator is provided. By keeping the compressed air as it is, the wheel cylinder continues to operate the brake.

FIG. 10 shows an example of a conventional solenoid valve provided on the brake pressure control valve as described above (see Japanese Patent Application Laid-Open No. Hei 10-250566). And a core 14 inserted into the inner peripheral portion of the electromagnetic coil 8 via a tube 10 and fixed to the case 6.
A plunger 16 disposed opposite to the core 14 and capable of moving forward and backward toward the core 14;
And a valve mechanism 36 that is opened and closed by the valve element 24 connected to the plunger 16.

As shown in FIG. 11A, the magnetic force generating portion of the conventional direct acting solenoid 2 in which the end surface 14a of the core 14 and the end surface 16b of the plunger 16 face each other is flat. It has a shape. In addition to such a conventional shape, as shown in FIG. 2B, the tip 16d of the plunger 16 has a conical shape, while the end face of the opposing core 14 has a conical portion 16 of the plunger 16.
d, or a tapered concave portion 14d for receiving the convex portion 14b, or a convex portion 14b protruding in a circular shape formed on the distal end surface of the core 14, and a concave portion 16c for receiving the convex portion 14b at the distal end of the plunger 16. Is conventionally known.

[0006]

The equipment mounted on a vehicle is required to be smaller and lighter.
It is strongly desired that the electromagnetic valve incorporated in the brake pressure control valve be reduced in size and weight. Therefore, the present invention improves the magnetic attraction force and the minimum operating voltage of a solenoid valve used for the above-described brake pressure control valve and a direct acting solenoid used for various other solenoid valves, and realizes a small and light direct valve. The purpose of the present invention is to provide a dynamic solenoid.

[0007]

A direct acting solenoid according to the present invention comprises a case, a coil housed in the case, and one end inserted into the inner periphery of the coil.
A core having the other end fixed to the case, a plate for fixing the coil in the case, and a tip end slidably inserted into an inner peripheral portion of the coil, and a tip end surface of the core is And a plunger opposed to the end face. In particular, a convex portion is provided on one of the opposing surfaces of the core and the plunger, and a concave portion on which the convex portion is fitted during operation is provided. An annular groove is formed on the surface.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 shows an electromagnetic valve provided with a direct acting solenoid 2 according to one embodiment of the present invention, and this electromagnetic valve is assembled to a body 4 of a brake pressure control valve. The solenoid 2 of the solenoid valve includes an electromagnetic coil 8 housed in a case 6, a non-magnetic (brass or the like) tube 10 fixed to the inner peripheral surface of the electromagnetic coil 8, and an O-ring inside the tube 10. A core 14 made of a magnetic material (stainless steel or the like) having one end (the upper end in the figure) fixed to the case 6 and inserted into the tube 10 from the end opposite to the core 14 A plunger 16 made of a magnetic material such as stainless steel and capable of moving forward and backward toward the core 14, and an electromagnetic coil 8 located on the lower end surface of the case 6;
And a plate 18 attached to the body 4 of the brake pressure control valve, and a plunger formed in a central portion of the plunger 16 and disposed in an axial hole 16a opened on the core 14 side. And 16 return springs 20.

In this embodiment, the case 6 corresponds to FIG.
As shown in FIG. 3, the shape viewed from above is a cross shape, and the tips 6 c of the four legs 6 b bent at right angles from the upper surface 6 a are further bent outward at right angles. Each of the bent portions 6c is provided with a mounting hole 6d. The cross-shaped case 6 is fixed to the plate 18 through these mounting holes 6d.

[0010] The plunger 16 of the direct acting solenoid 2
Is housed in a valve chamber 22 (in this embodiment, a signal pressure chamber of the brake pressure control valve) formed inside the body 4 of the brake pressure control valve, and has a valve body 24 having upper and lower valve portions 24a, 24b. Through a pin 26. Valve body 24
The upper and lower valve portions 24a and 24b are seated or unseated on the seat 30 on the discharge passage 28 provided in the upper part of the valve chamber 22 and the seat 34 on the introduction passage 32 provided in the lower part, respectively. The valve body 24 and the upper and lower seats 30 and 34 constitute a valve mechanism 36 that is opened and closed by the solenoid 2.

In the solenoid valve having the above-described structure, when the solenoid 2 is not excited, the plunger 16 is pushed downward by the return spring 20 in FIG. At the same time, the lower valve portion 24b is seated on the seat 34 on the introduction passage 32 side. When the solenoid 2 is excited, the plunger 16 moves upward in FIG. 1, the upper valve portion 24a of the valve body 24 is seated on the seat 30 on the discharge passage 28 side, and the lower valve portion 24b is introduced. Compressed air is introduced from an air tank (not shown) into the valve chamber 22 while being separated from the seat 34 on the passage 32 side.

Further, in this embodiment, the shape of the magnetic force generating portion where the core 14 and the plunger 16 face each other is shown in FIG.
As shown in FIG. 11A, an opposing portion between the core 14 and the plunger 16 in the conventional solenoid 2 (FIG.
(See (b) and (c)). That is, a columnar convex portion 14b is formed on the end surface 14a of the core 14,
At the base of the convex portion 14b, a constriction (annular groove) 14c is formed in parallel with the end surface 14a. On the other hand, a circular concave portion 16c that receives the columnar convex portion 14b when the plunger 16 is operated is provided on the distal end surface 16b of the plunger 16. By changing the shape of the magnetic force generating portion in this way, the magnetic attraction force can be increased, the minimum operating voltage can be reduced, and the performance of the solenoid 2 can be improved as compared with the conventional solenoid 2. Therefore, in order to obtain the same magnetic attraction force and minimum operating voltage as the solenoid 2 according to the conventional configuration, the coil wire diameter and the number of turns can be reduced, and the size and weight of the direct acting solenoid 2 can be reduced. Can be planned.

[0013]

EXAMPLES In order to confirm the above effects, a confirmation test was conducted on the performance of a direct acting solenoid according to one embodiment of the present invention and a solenoid having a core and a plunger of a conventional shape. First, as a first confirmation test, a magnetic attraction force test was performed under the following conditions. Sample As an example of the present invention, a direct acting solenoid 2 having a core 14 and a plunger 16 having the shape and dimensions shown in FIG. 5 was used, and as a comparative object, as a conventional product 1 (hereinafter, referred to as a flat type). A direct-acting solenoid 2 having a core 14 and a plunger 16 having the shape shown in FIG. The material of the core 14 and the plunger 16 is stainless steel SUS403, and the entire length of the plunger 16 is 22 mm. The coil 8 has a wire diameter of φ0.28.
× The same conditions are used for 1770 turns and 38Ω. 2. Test Method The solenoid 2 is arranged upside down from the state shown in FIG. 1, the return spring 20 of the plunger 16 is removed, and the plunger 16 is connected to a load sensor (not shown).
Hanging through. In this state, the relationship between the magnetic gap and the magnetic attractive force is measured while applying a constant current to the coil 8 and moving the plunger 16 in a direction approaching the core 14. The magnetic gap is the distance between the end face 14a of the core 14 and the end face 16b of the plunger 16 indicated by reference numeral G1 in FIGS. 5 to 7, and the stroke of the plunger 16 is detected by a stroke sensor.
Is measured. The magnetic attraction force is obtained by measuring the force by which the plunger 16 is drawn to the core 14 by a load sensor that suspends the plunger 16. The constant current supplied to the electromagnetic coil 8 is (1) 0.526 amps (20
(2) 0.632 amps (24 volts). Normally, the battery voltage of a heavy-duty vehicle is 24 volts.
Was measured.

As a second confirmation test, a minimum operating voltage test was performed on the same sample as the first confirmation test.
The test method was performed by using the solenoid 2 according to the embodiment of the present invention.
Also, the flat type solenoids 2 of the conventional product 1 and the concavo-convex type solenoids 2 of the conventional product 2 are arranged in the same vertical relationship as in FIG. 1, and the return spring 20 is omitted. Then, the magnetic gap G1 between the plunger 16 and the core 14 is variously set and set (as shown in FIG. 9 described later, the magnetic gap G1).
The size of 1.2mm, 1.4mm, 1.6mm,
The voltage supplied to the coil 8 is gradually increased, and the voltage at which the plunger 16 starts to move is measured.

FIG. 8 is a graph showing the results of the first confirmation test (magnetic attraction test). The solid line indicates the data of the solenoid 2 according to the embodiment of the present invention, and the broken line indicates the flat type of the conventional product 1. The data and the dashed-dotted line indicate the data of the concavo-convex type of the conventional product 2, respectively. The upper right pair indicates the case where a current (voltage) of 0.632 amperes (24 volts) was supplied to the electromagnetic coil 8, and the lower left portion Are supplied with a current (voltage) of 0.526 amps (20 volts).

As is clear from the above graphs, in any case, the magnetic attraction to the magnetic gap G1 increases as the magnetic gap G1 decreases, and increases as the supply current (supply voltage) of the coil 8 increases. .

When the data of each sample is compared,
The uneven type of the conventional product 2 (see FIG. 7) and the embodiment of the present invention (FIG. 5)
), The opening surface of the recess 16 c of the plunger 16 (that is, the tip surface 16 b of the plunger 16) is
(The magnetic gap G)
(When the size of 1 is 1.1 mm), the relationship of the magnetic attraction force of each sample is reversed. That is, when the magnetic gap G1 is larger than the above position (the position where the size of the magnetic gap is 1.1 mm), the magnitude of the magnetic attraction force is the flat type of the conventional product 1 <the concave and convex type of the conventional product 2 < Embodiment of the present invention: Case 1 where the embodiment of the present invention is the largest. When the magnetic gap G1 is smaller than the above position, the magnitude of the magnetic attraction force is as shown in the embodiment of the present invention <the concave / convex type of the conventional product 2 <the flat type of the conventional product 1... Is the smallest. Therefore, the gradient of the magnetic attraction force with respect to the size of the magnetic gap G1 is as shown in the embodiment of the present invention <the uneven type of the conventional product 2 <the flat type of the conventional product 1.

When the valve opening amount of the valve using the solenoid is 1
If it is not less than 1 mm, the stroke of the plunger must be 1 mm or more. For example, in the brake pressure control valve shown in FIG. 1, the valve opening amount (the air gap G of the valve mechanism 36)
2) is set to 1.2 mm, the magnetic gap G1 of the solenoid 2 used for this brake pressure control valve needs to be 1.2 mm or more. Under the conditions in which the solenoid 2 is actually used, the solenoid 2 according to the embodiment of the present invention has the largest magnetic attraction force, which is advantageous for miniaturization of the solenoid 2. The maximum stroke of the plunger 16 is the magnetic gap G1 when the solenoid 2 is not operated.
Is equivalent to

FIG. 9 is a graph showing the results of the second confirmation test (minimum operating voltage test). Like the graph showing the results of the first confirmation test (magnetic attraction force test), the solid line shows the results. The data of the solenoid 2 according to the embodiment of the present invention, the broken line shows the flat type data of the conventional product 1, and the dashed line shows the uneven type data of the conventional product 2, respectively. The second confirmation test was performed only in case 1 of the first confirmation test (when the size of the magnetic gap G1 was 1.1 mm or more).

In this test, the minimum operating voltage was as follows: the embodiment of the present invention <concavo-convex type of conventional product 2 <flat type of conventional product 1, and solenoid 2 according to the embodiment of the present invention was compared with the conventional product. The minimum operating voltage is the smallest.

From the results of the above confirmation test, for example, in the case of the solenoid 2 used for the brake pressure control valve, the solenoid 2 according to the embodiment of the present invention has the largest magnetic attraction force and the lowest operating voltage. It is clear that the performance of the solenoid 2 is improved as compared with the conventional solenoid 2. When the solenoid 2 according to the embodiment of the present invention is applied to the brake pressure control valve, in order to obtain the same magnetic attraction force and minimum operating voltage as the flat type of the conventional product 2, for example, the conventional product 2 Is a coil wire diameter φ0.32 × 2600 turns (45Ω), the solenoid 2 of the present invention has a coil wire diameter φ0.28 ×
It may be 1770 turns (38Ω). From the above results. The solenoid 2 according to the embodiment of the present invention is smaller than the conventional one,
Lightening can be achieved.

Further, by changing the size of the convex and concave portions of the core and the plunger, or the size of the annular groove, a design corresponding to the load of the solenoid can be made. Moreover, by changing the curve of the magnetic attractive force characteristic with respect to the magnetic gap, it is possible to obtain a larger magnetic attractive force at a large magnetic gap.

In the above-described embodiment, the projection 14b having the annular groove 14c is provided on the core 14 side, and the recess 16c for receiving the projection 14b on the plunger 16.
Contrary to this configuration, a projection and an annular groove are formed on the plunger 16 side, and the plunger 1
A concave portion capable of receiving the convex portion of No. 6 may be formed.

[0024]

As described above, the direct acting solenoid according to the present invention is provided with a convex portion on one of the surfaces where the core and the plunger face each other, and a concave portion on which the convex portion is fitted during operation. Since the annular groove is formed on the outer peripheral surface of the convex portion, under the condition that this solenoid is used, the magnetic attraction force can be increased and the minimum operating voltage can be reduced as compared with the conventional solenoid. The dynamic solenoid can be reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a solenoid valve provided with a direct acting solenoid according to one embodiment of the present invention.

FIG. 2 is a plan view of the solenoid valve.

FIG. 3 is a perspective view of a case of the direct acting solenoid.

FIG. 4 is an enlarged view showing a magnetic force generating portion where a core and a plunger of the direct acting solenoid face each other.

FIG. 5 is a diagram showing a core and a plunger according to one embodiment of the present invention as a sample on which a test for confirming performance is performed.

FIG. 6 is a view showing a conventional product 1 as the sample.

FIG. 7 is a view showing a conventional product 2 as the sample.

FIG. 8 is a graph showing the results of confirmation test 1 (magnetic attraction test).

FIG. 9 is a graph showing the results of confirmation test 2 (minimum operating voltage test).

FIG. 10 is a longitudinal sectional view of a conventional solenoid valve including a direct acting solenoid.

FIGS. 11A, 11B and 11C are diagrams showing different shapes of conventional magnetic force generating parts.

[Explanation of symbols]

 6 Case 8 Coil 14 Core 14a Surface of core facing plunger (end surface) 14b Projection of core 14c Annular groove 16 Plunger 16b Surface of plunger facing end of core (end surface) 16c Depression of plunger 18 Plate

Continued on front page F-term (reference) 3D049 BB39 CC05 HH03 HH20 HH31 HH34 HH54 3H106 DA07 DA23 DB21 DB22 DB23 DC02 EE17 EE22 EE23 EE34 GA13 GA15 GC04 KK22 5E048 AA08 AB01 AD04 5H633 BB07 BB10 J05GG05 GG04 GG02 GG05 GG02 GG05

Claims (2)

[Claims] 1. A case, a coil accommodated in the case, a core having one end inserted into an inner peripheral portion of the coil and the other end fixed to the case, and the coil connected to the case. And a plunger slidably inserted into the inner peripheral portion of the coil with its tip end face facing the end face of the core, wherein the plunger is opposed to the core and the plunger. A direct acting solenoid characterized in that a convex portion is provided on one of the surfaces to be formed, and a concave portion on which the convex portion is fitted at the time of operation is provided, and an annular groove is formed on the outer peripheral surface of the convex portion. 2. The direct acting solenoid according to claim 1, wherein the direct acting solenoid controls a pressure control valve.