JPH0648649B2 - Electromagnetic control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electromagnetic control device for controlling the operation of various devices using an electromagnetic attraction force, such as a current control valve for fluid pressure adjustment.

[Prior Art] In a conventional solenoid valve, as disclosed in, for example, Japanese Patent Laid-Open No. 59-37309, a coil is externally fitted to a magnetic cylindrical body that also serves as a fluid flow path and a core to form an electromagnet. A plunger that floats based on the magnetic attraction force of the electromagnet while receiving the movement restraining force of the coil spring is provided in the inner space of the valve body, and the valve body incorporated at the end of the plunger opens and closes in response to the movement of the plunger. Is configured.

[Problems to be Solved by the Invention] In the above-described conventional solenoid valve, the magnetic attraction force generating air gap for attracting the plunger includes the annular cylinder end surface of the magnetic cylinder located inside the coil, and the plunger. Since it is formed in an annular shape with the end face in the floating direction, the surface area of the air gap has to be considerably smaller than the outer diameter of the solenoid valve.

If the magnetomotive force of the electromagnet is constant, it is necessary to widen the air gap area in order to maximize the magnetic attraction force. This is because the magnetic resistance exhibited by the air gap can be reduced by increasing the air gap area, in other words, the surface area of the magnetic poles. The magnetic resistance R of the air gap is expressed by the following equation.

R = I / μS I: Distance between magnetic poles μ: Permeability of air gap S: Magnetic pole surface area Therefore, in order to keep the magnetic attraction force of the electromagnetic control device at a high level and make the device as compact as possible, the magnetic pole surface area should be as wide as possible. Need to be designed to take.

Therefore, an object of the present invention is to provide an electromagnetic control device in which the magnetic attraction force is kept at a high level and the device is made as compact as possible.

[Means for Solving the Problems] In order to achieve the above object, an electromagnetic control device of the present invention is a core outer cylinder, a core inner cylinder arranged on an inner peripheral side thereof, the core outer cylinder and a core inner part. An electromagnet having a magnetic cylinder made up of an end face plate coaxially joining one end of the cylinder, the coil being fitted between the core outer cylinder and the core inner cylinder of the magnetic cylinder; In the electromagnetic control device comprising a plunger slidably fitted in the inner hollow portion of the core inner cylinder on the opening side of the electromagnet, and a spring for urging the plunger in a direction away from the electromagnet, the plunger is A disk portion having one end abutting the spring and the other end extending in the radial direction, and an axial direction from the outer peripheral portion of the disk portion so as to face the core outer cylinder on the radially outer side of the coil. A movable magnetic cylinder extending to the core outer cylinder and the plastic cylinder. An air gap that generates a magnetic attraction force is formed between the nudger and the movable magnetic cylinder.

[Operation and Effect of the Invention] When the coil of the electromagnet is energized, the electromagnetic control device of the present invention as described above includes a magnetic cylindrical body (core outer cylinder) as a core material of the magnet located on the outer peripheral side of the coil, and an electromagnet. In the air gap formed between the plunger and the movable magnetic cylinder that is loosely fitted in the inner space, a magnetic attraction force is generated according to the amount of energization, so the plunger energizes against the pressing force of the spring. The distance corresponding to the amount is attracted to the inner space of the electromagnet. The purpose of control is fulfilled by transmitting the movement of the plunger to the control actuation mechanism of the controlled object.

Therefore, the surface area of the air gap can be increased as compared with the structure in which the air gap is provided inside the coil, and a large magnetic attraction force can be generated. Further, the electric power required to generate the same magnetic attraction force is smaller than that of the conventional device.

[Embodiment] An embodiment of the electromagnetic control apparatus of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an assembled state as a specific example of the electromagnetic control device of the present invention, in which A is a solenoid portion, B is a plunger portion loosely fitted in the central inner space of the solenoid portion A, and C is the solenoid portion. It is a spool valve portion that is actuated and controlled by the movement of the plunger portion B.

The solenoid portion A is a core outer cylinder having a double cylinder shape composed of a core outer cylinder 1 as a magnetic cylinder, a core inner cylinder 2 and an end face plate 3 for coaxially combining these inner and outer cylinders. The coil 4 is internally fitted into the coil 1. 5 is a bobbin of the coil 4, and 17 is a ventilation hole provided in the end face plate 3. By providing an annular notch on the inner peripheral side at the free end (right end in the figure) of the core outer cylinder 1, two annular magnetic poles, that is, the inner magnetic pole 10 and the outer magnetic pole 11, are formed in a paragraph shape. ing. The double cylindrical core may have a seamless integral structure.

The plunger portion B includes a cylindrical plunger main body 7 loosely fitted in the core inner cylinder 2, a circular disk 9 coaxially fixed to the rear end of the main cylinder 7, and an outer peripheral edge of the circular disk 9. The core outer cylinder 1 is formed by combining with the inner magnetic pole 10 and a movable magnetic cylinder 8 having a diameter substantially the same as that of the core outer cylinder 1 attached so as to face the inner magnetic pole 10. A circular groove 15 for fitting a Teflon sliding ring 16 is provided near both ends of the plunger main body 7, and a forward movement restricting stopper 14 for the plunger B is provided at the rear end. 13 is the core inner cylinder 2
Is a member facing the stopper 14 made of a non-magnetic material attached to the end of the cylinder. The plunger portion B may be formed into a seamless integral structure by cutting or casting.

The free end 12 of the movable magnetic cylinder 8 is the core outer cylinder 1 (magnetic cylinder).
The air gap 4 of the planar electromagnet between the inner magnetic pole 10 and
4 is formed, and an air gap 45 of the leakage type electromagnet is formed between the outer magnetic pole 11 and the outer magnetic pole 11.

The spool valve portion C includes a sleeve 30, a fluid pressure input port 31, a fluid pressure output port 32, a drain port 33,
A feedback control port 35 for adjusting the position of the spool 34 according to the fluid pressure of the spool 34 and the output port 32, and means for transmitting the movement of the plunger portion B to the spool 34, in this case, the plunger portion B.
Is provided with a combination mechanism of an extension spring 6 for urging the spool 34 in the backward direction and a feedback control pressure for pressing the spool 34 toward the plunger portion B. A flange-shaped portion 19 is provided at one end of the sleeve 30, and the tip end of the cylindrical body 20 joined to the peripheral portion of the flange-shaped portion 19 is screwed onto the free end of the core outer cylinder 1. The solenoid portion A, the plunger portion B, and the spool valve portion C are joined together. 21 is a flange-shaped portion 1
9 is a backward movement restricting stopper of the plunger portion B provided at 9, 9 is a backward movement restricting stopper of the spool 34, and 37 is a fluid pressure distribution hole provided at the stopper 36.

FIG. 2 is a graph showing how the combined attractive force of the magnetic attractive forces generated in the air gap 44 of the planar electromagnet and the air gap 45 of the leakage electromagnet changes with the movement of the plunger portion B. The vertical axis represents the magnetic attraction force, and the horizontal axis represents the moving distance of the plunger. Graph A shows the attractive force of the planar electromagnet, graph B shows the attractive force of the leakage type electromagnet, and graph C shows the attractive force as a combined force of the magnetic attractive forces of these electromagnets. There is.

Next, the operation of the electromagnetic control device of the present invention will be described. When the solenoid coil 4 is not energized, the control pressure flowing into the feedback control port 31 and the spring action force of the spring 6 balance each other to regulate the pressure to a constant pressure at the crack point. This current proportional control valve spool 34
The control pressure that flows from the fluid pressure input port 31 through the output port 32 into the feedback control port 35 is exerted on the right end face (FIG. 1) of the spring, and the left end face is flat and the leakage due to the spring action force of the spring 6. Since the pressure obtained by subtracting the composite magnetic attraction force exerted by the die electromagnet is exerted, the following force relationship of mutual pressing action force is established between the spool 34 and the plunger portion B.

F1-F2 = P * A ... (a) F1: Spring action force of the spring 6 F2: Composite magnetic attraction force which both plane type and leakage type electromagnets present P: Control pressure (feedback pressure) A: Spool 34 As shown in FIG. 2, the distance that the plunger portion B moves as the spool 34 is pushed by the control pressure exerted on the feedback control port 35 of the spool valve, the planar electromagnet, and A transitional relationship as shown in the graphs A and B occurs between the current attraction force generated in the air gaps 44 and 45 of the leakage type electromagnet. Further, between the composite suction force generated in both air gaps and the moving distance of the plunger portion B, as shown in the graph C, the magnetic attraction force is not exerted on the plunger portion B at the zero point in the graph of FIG. While the air gap 44 of the planar electromagnet gradually moves from the position shown in the direction of the distance L1 for the distance L1, the magnetic attraction force rapidly increases as the moving distance increases. The magnetic attraction force hardly increases during the movement between the two. The shape of such a graph is obtained by appropriately selecting the shape of the cutout portion of the end surface of the core outer cylinder 1 (or the movable magnetic body 8). If an air gap of the electromagnet is formed so as to generate such an invariable region of the magnetic attraction force (range of b → c shown in graph C), the composite magnetic attraction force in the above formula (a) is formed. F2 does not change as long as the plunger part B moves within the range of the distance L1 → L2 in FIG. 2 and under the condition that the current flowing through the electromagnet is kept constant, and therefore the above formula is obtained. In (a), the value of F2 becomes a constant and the spool 34
The pressure regulating operation of is performed only in the balance relationship between the control pressure P exerted on the feedback control port 35 and the spring action force F1 of the spring 6 that presses the plunger portion B toward the spool 34. The influence of the fluctuation of the magnetic attraction force between the air gaps of the electromagnet due to the movement can be reduced to zero.

Plunger part B moves inside the core outer cylinder 2 as indicated by L1 in FIG.
In this embodiment, which is a specific measure for making the movement only within the range of → L2, the backward movement restriction stopper 21 and the forward movement restriction stopper 14 of the plunger portion B and the facing member 13 thereof are provided. Even if the amount of electricity supplied to the coil 4 changes, the magnetic attraction force generated in the air gap does not change even if the plunger portion B is displaced along with the movement of the spool 34 because the air gap shape is set as described above. Therefore, the value on the left side of the equation (a) changes in proportion to the change of the composite magnetic attraction force F2 which is governed only by the energization amount of the coil 4, and therefore the control pressure P on the right side is the energization amount of the electromagnet. Since the spool 34 is displaced in direct proportion to the increase / decrease degree, ideal operation of the current proportional control pressure is ensured.

In the current proportional control valve, when the control current is constant, it is desirable that the magnetic attraction force is constant regardless of the position of the plunger 34, but the control valve of the present invention has already been described with reference to FIG. This desirable condition is met. In order to strengthen the magnetic attraction force maintained at this constant level and to make the outer diameter of the control valve compact, the position of the air gap as the magnetic attraction force generation space is set inside the coil 4 as in the conventional case. Instead, the leakage-type electromagnet is incorporated under the condition that it is set outside the coil 4 and is incorporated into the planar electromagnet.

In the embodiment of the present invention shown in FIG. 1, the core outer cylinder 1 (magnetic cylinder) is formed in order to form the magnetic poles of a composite type electromagnet in which two types of flat type and leakage type electromagnets are combined. Although the paragraph-shaped notch is provided at the tube end, the notch may be provided at the tube end of the movable magnetic tube 8 or at both tube ends.

As described above, in the electromagnetic control device of the present invention, since the air gap for generating the magnetic attraction force is formed radially inward in the conventional electromagnetic control device, the air gap surface area must be remarkably small. On the other hand, in the electromagnetic control device of the present invention, by forming the air gap outside the coil, the surface area of the air gap can be increased and a large magnetic attraction force can be generated.

In addition, less electric power is required to generate the same magnetic attraction force as compared with the conventional device.

In addition to the control of the spool valve as the current proportional control valve shown in the above embodiment, the electromagnetic control device of the present invention has the purpose of controlling the operation of various devices through the forward / backward movement of the plunger portion B. Can be utilized.

[Brief description of drawings]

FIG. 1 is a diagram of an assembled state of an electromagnetic control device of the present invention, and FIG. 2 is a magnetic attraction force exhibited by two types of flat and leakage type electromagnets in which the electromagnetic control device is incorporated, and a plunger in the electromagnetic control device. 6 is a graph showing a relationship with a distance moved by a magnetic force. A: Solenoid part B: Plunger part C: Spool valve part 1 ... Magnetic cylinder 4 ... Coil 6 ... Spring 7 ... Plunger mainly 8 ... Movable magnetic cylinder 10 ... Inner magnetic pole 11 Outer magnetic pole 12 Free end of movable magnetic cylinder 34 Spool 44 Air gap of flat electromagnet 45 Air gap of leakage electromagnet

Claims (1)

[Claims] 1. A magnetic cylinder body comprising a core outer cylinder, a core inner cylinder arranged on an inner peripheral side thereof, and an end face plate coaxially joining one ends of the core outer cylinder and the core inner cylinder. An electromagnet formed by inserting a coil between the core outer cylinder and the core inner cylinder of the magnetic cylinder; and an electromagnet slidably fitted in the inner space of the core inner cylinder on the opening side of the electromagnet. And a spring for urging the plunger in a direction to move the plunger away from the electromagnet, the plunger has one end in contact with the spring and the other end in a radial direction. A movable magnetic cylindrical body that extends axially from the outer peripheral portion of the disk portion so as to face the core outer cylinder on the radially outer side of the coil, the core outer cylinder and the plunger An air gap that creates a magnetic attraction force is formed between the movable magnetic cylinder and An electromagnetic control device characterized by the above.