JPH0241678B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention circulates working fluid between a storage chamber and a pressure chamber using an electromagnetic pump, thereby generating a driving force for driving a load using the pressure generated within the pressure chamber. Regarding an actuator that obtains the following.

In this type of actuator, if the resistance given to the working fluid returning from the pressure chamber to the storage chamber is constant, the pressure generated in the pressure chamber corresponds to the discharge flow rate of the electromagnetic pump, and this discharge flow rate Corresponds to the amount of drive current of the pump. Therefore, there is a certain functional relationship between the pressure in the pressure chamber (that is, the amount of movement of the responding body) and the amount of driving current of the electromagnetic pump, but in reality, the relationship between the two differs for each actuator. Desired operating characteristics cannot be obtained by controlling only the amount of drive current.

Further, the electromagnetic pump described above is widely known to have a structure in which a plunger reciprocates within a circular tube, and fluid is sucked from one end of the cylinder and discharged from the other end by the opening and closing action of a check valve.

However, when such an electromagnetic pump is installed in a device in which the liquid suction port and discharge port are provided in the same plane, for example, separate piping must be installed from the discharge side through the outside of the pump to the suction side. The problem was that the structure was complicated, the cost was high, and the external size was increased due to the piping.

An object of the present invention is to provide a small, inexpensive actuator that can be adjusted to obtain a load shift amount corresponding to the amount of drive current.

Next, an embodiment of the present invention will be described with reference to the drawings. The flow control device shown in the figure is composed of a pressure generating section A that generates hydraulic pressure, a converting section B that converts this hydraulic pressure into displacement, and a control section C that is driven by this converting section B. This example shows a flow control device configured to control the flow rate of fuel gas supplied to a combustor, such as a water heater.

The pressure generating section A is an electromagnetic pump 13 consisting of a coil 11 and an actuating section 12 penetrating through the center hole thereof.
has. This electromagnetic pump 13 sucks the hydraulic oil contained in the storage chamber 14 from the passage 15 into the actuating part 12, and then passes it through the passage 16 to the pressure chamber 1.
7. Moreover, the pressure chamber 17 is
It communicates with the storage chamber 4 via a passage 18 provided with an orifice having an appropriate opening area, and also communicates with the second pressure chamber 20 via a passage 19. Therefore, when the electromagnetic pump 13 operates, the hydraulic oil circulates from the storage chamber 14 through the passage 15, the actuating section 12, the passage 16, the pressure chamber 17, and the passage 18, and returns to the storage chamber 14. Due to the action of the orifice, a pressure corresponding to the discharge flow rate of the electromagnetic pump 13 is generated in the pressure chamber 17. This pressure is also transmitted to the pressure chamber 20 via the passage 19.

On the other hand, a bypass passage 22 is formed that connects the suction side passage 15 and the discharge side passage 16 of the electromagnetic pump 13, and the bypass passage 22 is in a closed position only while the electromagnetic pump 13 is operating normally. A retained bypass valve 23 is provided. Therefore, when the electromagnetic pump 13 stops operating after the pressure in the pressure chamber 17 has increased, the bypass valve 23 immediately moves to the open position, thereby causing the pressure chamber 17 to rise.
The pressure inside is instantly released.

Conversion section B provided adjacent to pressure generation section A
has two reaction bodies 31 and 32. 1st
The response body 31 is in contact with the inside of the pressure chamber 17 via a bellows frame, and is fixed to the tip of a rod 33 that is movable in the axial direction, and is supported by a spring 34.
is urged toward the inside of the pressure chamber 17 by.
The second response body 32 is in contact with the pressure chamber 20 via a bellows frame, and is supported by the tip of a rod 35 that is movable in the axial direction, and directed toward the inside of the pressure chamber 20 by a spring 36. is being pressed down. Therefore, when the pressure in pressure chambers 17 and 20 increases, reaction bodies 31 and 32 move against springs 34 and 36, respectively,
When the pressure decreases, it returns to its original position, and pressure-displacement conversion is performed here. The pressure receiving area of the second reaction body 32 is smaller than that of the first reaction body 31, and therefore the pressure at which the second reaction body 32 starts to be displaced is higher than that of the first reaction body 31.

The control section C has an inlet passage 41, a communication passage 42, and an outlet passage 43, and preferably a regulator (not shown) is provided in the communication passage 42. The inlet passage 41 and the communication passage 42 communicate with each other through a center hole of a valve seat 44 , and an on-off valve 45 is pressed against the valve seat 44 by the action of a spring 46 . and a valve rod 47 that supports the on-off valve 45.
is in contact with the tip of the rod 33 mentioned above. Further, the communication passage 42 and the outlet passage 43 are connected to the valve seat 48.
A proportional valve 50 is pressed against the valve seat 48 by a spring 49. A valve rod 51 provided at the center of the proportional valve 50 is in contact with the tip of the rod 36 at one end thereof. This proportional valve 50 has a valve seat 48
By moving within the range between the fully closed position that is in close contact with the
2 to the outlet passage 43 can be proportionally controlled.

FIG. 2 shows the main parts of the actuating part 12 of the electromagnetic pump 13, and the cylinder indicated by the reference numeral 61 is the coil 11.
It passes through the center of the cap and its tip is sealed with a cap 62. A substantially cylindrical fixed core 63 and plunger 64 are housed within this cylinder 61. The fixed core 63 is fixed with its outer peripheral surface facing the inner peripheral surface of the cylinder 61, has a groove 65 communicating with the passage 16 (FIG. 1), and has a cylindrical body inserted into the center hole. 66 is supported. One end of a sleeve 67 enters into this cylindrical body 66 so as to be slidable in the axial direction.
The other end of 7 is fixed to one end of plunger 64. Furthermore, a check valve consisting of a valve seat 68 and a spherical valve body 70 which is pressed onto the valve seat 68 by a spring 69 is supported within the sleeve 67 . The inside of the cylindrical body 66 communicates with the passage 15 (FIG. 1) via a check valve (not shown).

On the other hand, the plunger 64 has a groove 71 extending in the axial direction on its circumferential surface, and is movable in the axial direction while slidingly contacting the inner circumferential surface of the cylinder 61. The fixed core 63 is biased by the second spring 73 toward the fixed core 63 . Therefore, the plunger 64 remains stationary at a position where the first spring 72 and the second spring 73 are balanced. Further, a disk-shaped spring receiver 74, which one end of the second spring 73 comes into contact with, engages with the tip of an adjusting screw 75 in a state where only rotation is allowed. Section 76
It is screwed together. Therefore, when the adjusting screw 75 is rotated to move it forward or backward, the second spring 73
The position of one end of the plunger 64 changes, resulting in a change in the rest position of the plunger 64.

In the electromagnetic pump configured as described above, when a drive current of an arbitrary waveform such as a half-wave rectified sine wave or a square wave is supplied to the coil 11,
The magnetic attraction force acting on the magnetic gap formed between the fixed core 63 and the plunger 64 changes periodically, causing the plunger 64 to reciprocate and pump the working fluid. That is, in the process of the plunger 64 approaching the fixed core 63, the above-mentioned two
Due to the action of the two check valves, working fluid is sucked into the chamber formed above the plunger 64 from the passage 15 communicating with the storage chamber 14 through the internal passage that communicates the center holes of the cylinder 66 and the sleeve 67. In the process of the plunger 64 leaving the fixed core 63, working fluid is pumped into the passage 16 on the same side as the passage 15 in the chamber through an external passage consisting of grooves 71 and 65 communicating with the internal passage.

Now, paying attention to the magnetic gap formed between the fixed core 63 and the plunger 64, as shown in FIG. A magnetic gap is formed, and the plunger 64 reciprocates based on this gap d.
This interval d is extremely important in determining the operating characteristics of the electromagnetic pump, that is, the relationship between the energy of the drive signal supplied to the coil 11 and the discharge flow rate of the working fluid, and this value must be the same for each electromagnetic pump. If so, they have certain operating characteristics. However, as a practical matter, due to variations in the spring constant and length of the springs 72 and 73,
It is extremely difficult to maintain a constant value for the distance d, which causes the operating characteristics of each electromagnetic pump and, ultimately, the operating characteristics as an actuator to become non-uniform. However, in the actuator of the present invention, by changing the position of the spring receiver 74 via the adjustment screw 75, the second spring 7
By changing the position of one end of 3, the value of the distance d can be easily adjusted from the outside. Therefore, even if there are variations in the distance d between the electromagnetic pumps, it is possible to adjust them to the desired operating characteristics through subsequent adjustment work, and it is possible to obtain an actuator with constant characteristics. . This means that the amount of load movement can be easily and accurately controlled simply by adjusting the energy of the drive signal supplied to the coil 11 of the electromagnetic pump 13 by changing its pulse value and frequency. However, this is particularly advantageous when proportional control of the valve as shown in FIG. 1 is performed.

In addition, an internal passage and an external passage are formed within the cylinder,
One end of both passages is communicated with each other inside one end of the cylinder, and the other end is opened at the other end of the cylinder as an inlet port and a discharge port, so that the suction side and the discharge side can be formed in the same direction of the cylinder, and there is no outside of the cylinder. There is no need to provide separate piping, and the reduction in the number of sealing materials results in lower costs and a smaller size.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a flow control device equipped with an actuator according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a part of an electromagnetic pump of the actuator, and FIG. 3 is an explanation showing a magnetic gap. It is a diagram. A... Pressure generation section, B... Conversion section, C... Control section, 11... Coil, 12... Actuation section, 13...
Electromagnetic pump, 14...Storage chamber, 17, 20...Pressure chamber, 22...Bypass passage, 23...Bypass valve, 31, 32...Response body, 41...Inlet passage,
42...Connecting passage, 43...Exit passage, 44...
Valve seat, 45... Open/close valve, 48... Valve seat, 50...
Proportional valve, 61...Cylinder, 62...Cap, 63
... Fixed core, 64 ... Plunger, 65 ...
Groove, 66...Cylinder, 67...Sleeve, 68...
Valve seat, 70... Valve body, 71... Groove, 72, 73...
...Spring, 74...Spring receiver, 75...
Adjustment screw, 76...boss part.

Claims (1)

[Claims] 1 Pressed by a cylinder provided within the excitation coil, a fixed core having a valve body and provided at the center of the cylinder, and two springs acting in opposite directions, the magnetic flux from the excitation coil is a plunger that is provided so as to remain stationary at a predetermined position with respect to the fixed core when not in action and to reciprocate in response to changes in magnetic flux from the excitation coil; and a center hole between the fixed core and the plunger. an internal passage that communicates with the cylinder, an external passage formed between the cylinder, the fixed core, and the plunger, and an end of the spring provided to press the plunger toward the fixed core. A spring retainer movable in a direction parallel to the moving direction of the plunger while in contact with the plunger, and an adjusting screw for adjusting the position of the spring retainer, the inner passage and one end of the outer passage being connected to the cylinder. An actuator characterized in that one end is communicated with the other end of the cylinder and the other end is opened as an inlet and an outlet at the other end of the cylinder.