JPS61218802A - Negative pressure actuator - Google Patents

Abstract

PURPOSE:To reduce the hysteresis error of a negative pressure actuator by providing second bias means held by a plunger for moving the valve member of an electromagnetic pressure control valve and a piston in the body of the negative pressure actuator therebetween, and correcting the hysteresis. CONSTITUTION:The body 1 of a negative pressure actuator comprises a piston 4 which is integrally moved with a diaphragm 3 and a compression spring 5 for a negative pressure chamber. An electromagnetic pressure control valve 10 is provided on the opposite side of the diaphragm 3. Second bias means comprising a rod 40 and a bias spring 41 is provided in the center of the stationary iron core 13 of the pressure control valve 10. Negative pressure in the negative pressure chamber is changed by moving the piston. Thus, a hysteresis error can be corrected without an electrical control system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a negative pressure actuator that drives a piston using a negative pressure source, for example, in an automobile.
The present invention relates to a negative pressure actuator used for controlling the throttle position of an engine, controlling the temperature of an air conditioning control device, etc.

[Prior art] A conventional negative pressure actuator of this type is disclosed in Japanese Patent Application Laid-open No. 1983-
The technique disclosed in Japanese Patent No. 149634 can be mentioned.

The above technology is a negative pressure actuator in which a negative pressure chamber and an atmospheric chamber are partitioned by an airtight thin film such as a diaphragm, and a piston that closely responds to the diaphragm as pressure changes in the negative pressure chamber. i2! The device is characterized in that an inductance that continuously detects the position of the piston and generates an electrical signal is built in the negative pressure chamber, and the inductance is connected to a coil that is statically fixed in the negative pressure chamber. The iron core has a structure in which the iron core strokes, and the iron core is maintained at a balance point between the forces of at least the first spring and the second spring, one end of the first spring is connected to the stationary part, and one end of the second spring is connected to the screws 1 to 1. They are configured so that they are in contact with each other.

In conventional negative pressure actuators such as those mentioned above, changes in inductance that are linked to the piston are fed back to the electric control device that adjusts the negative pressure to the negative pressure actuator. If the actuation amount of the rod cannot be obtained by the negative pressure actuator, the signal of the electric control device can be automatically corrected to change the pressure in the negative pressure chamber to correct the protruding position of the rod of the negative pressure actuator.

[Problem to be solved by the invention 1 However, in conventional negative pressure actuators of this type, mechanical imbalance is electrically detected, electrically processed as a signal, and then converted back into mechanical displacement. Therefore, the configuration for correction, especially the electric control device, etc., became complicated and expensive.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a negative pressure actuator that reduces hysteresis errors without using an electrical control system.

[Means for Solving the Problems] The negative pressure actuator according to the present invention includes a negative pressure chamber and an atmospheric chamber partitioned by an airtight thin film such as a diaphragm, and a first attachment disposed within the negative pressure chamber. a negative pressure actuator main body having a pressure means, a piston that closely responds to the thin film as pressure changes in the negative pressure chamber, and an input port that introduces negative pressure into the negative pressure chamber; and a negative pressure actuator body that opens and closes the input port. an electromagnetic pressure valve having a valve body that moves the valve body, a plunger that moves the valve body, and a coil that drives the plunger p by the magnetic force generated by the plunger p-, which is sandwiched between the plunger and the piston, This is an electromagnetic pressure control valve having a second biasing means consisting of a rod and a biasing spring that biases the valve body.

[Function] In the present invention, since the second biasing means is sandwiched between the piston of the negative pressure actuator main body and the plunger of the electromagnetic pressure control valve, the influence of load etc. on the piston side is avoided. When the piston position does not return to its original stop position and attempts to stop, the distance difference between the piston position where it attempts to stop and the piston position where it should originally return is determined by the second bias held between the piston and the plunger. This appears as a change in the biasing force of the means, and changes the negative pressure in the negative pressure chamber in order to return the screw that was about to stop to its original position, thereby returning the piston to its original position.

[Embodiment] FIG. 1 shows a sectional view of a negative pressure actuator according to an embodiment of the present invention.

In the figure, a negative pressure actuator main body 1 includes an actuator housing 2, a piston 4 that is displaced integrally with a diaphragm 3 made of an airtight thin film, etc., and a piston 4 that is interposed between the piston 4 and the actuator housing 2. a compression spring 5° for the negative pressure chamber of the first energizing means, a cable 6 that leads the displacement of the piston 4 from the center of the diaphragm 3 and the piston 4 to a load such as a throttle valve, and the actuator housing 2.
It consists of a diaphragm cover 7 disposed on the opening side, that is, on the diaphragm side.

The diaphragm 3 is interposed between the actuator housing 2 and the diaphragm cover 7, and fixes and seals the diaphragm cover 7 to the actuator housing 2 by caulking or the like. Further, the diaphragm 3 is guided by a piston 4 that closely responds to the diaphragm 3 so that no distortion occurs locally.

In this way, a negative pressure chamber A is constituted by the inner surface of the diaphragm 3 and the actuator housing 2, and an atmospheric chamber 8 is constituted by the outer surface of the diaphragm 3, the diaphragm cover 7, and the hole provided in the diaphragm cover 7. .

Diaphragm 3 arranged in actuator housing 2
On the opposite side, an electromagnetic pressure control valve 10 is fixed to the actuator housing 2, and the gap therebetween is sealed with a sealing member such as an O-ring.

The electromagnetic pressure control valve 10 is ?? It is composed of a magnetic control section and a valve body section.

The electromagnetic control section includes a solenoid formed by winding a coil 12 around a bobbin 11 made of synthetic resin or the like, and a fixed iron core 1 disposed at the axis of the solenoid, that is, inside the bobbin 11.
3, and a yoke 14 disposed around the solenoid to efficiently form a magnetic path in the fixed iron core 13 when the coil 12 is excited.

A valve body portion is provided at the tip of the electromagnetic control portion, as shown in an enlarged sectional view of the valve body portion in FIG.

The valve body portion includes a plunger 20 having an attachment auxiliary member 21 fixed to the end thereof, a poppet valve 23 energized by a valve energizing compression spring 22 held within the plunger, and the poppet valve. an input port 31 whose end is opened and closed at 23; a communication hole 25 formed in the plunger 20; a diaphragm 24 disposed between the auxiliary mounting member 21 and the valve body housing 30; and an atmospheric port 32.
, and an output port 33.

That is, the valve body portion has a poppet valve 23 energized by a valve energizing compression spring 22 held in a plunger *y-20 to which an auxiliary attachment member 21 is fixed at the end. The valve biasing compression spring 22 applies a valve closing force to close the input port 31. The input port 31 and the poppet valve 23 are opened and closed by the input port 31.
The poppet valve 23 is opened when the mounting auxiliary member 21 pulls it away from the poppet valve 23 , and the poppet valve 23 is opened when the input port 31 comes into contact with the poppet valve 23 and the poppet valve 23 is separated from the mounting auxiliary member 21 to close the poppet valve 23 . Since the valve is activated, the valve biasing compression spring 22 does not directly involve in opening and closing the input port 31. The inner periphery of a diaphragm 24 is baked and fixed to the mounting auxiliary member 21, and the outer periphery is fixed to a valve housing 30 made of synthetic resin or the like that guides each port up to or near the poppet valve 23. The valve body housing 30 and the mounting auxiliary member 21 are
The space between them is sealed by the diaphragm 24. A vacuum pump (not shown) or a surge tank storing negative pressure is connected to the input port 31 of the valve body housing 30, and the input port 31 is opened and closed by the poppet valve 23, and atmospheric pressure is connected to the plunge tF-20 and the poppet valve. An atmospheric port 32 that leads to the opposite side of the input port 31 of 23, and an output port 33 that leads the pressure of the input port 31 and the atmospheric port 32 to the negative pressure chamber A of the negative pressure actuator main body 1 under the control of the poppet valve 23 are provided. ing. An air filter head 34 having a built-in air filter 35 is firmly attached to the atmospheric side of the atmospheric port 32 with a sealing member 36 made of rubber or the like interposed therebetween. Further, the output port 33 and the negative pressure chamber A are communicated through a guide tube 37 made of rubber, synthetic resin, or the like.

An energizing spring 41 consisting of a rod 40 and a compression spring is inserted between the piston 4 and the plunger 20 at the axial center of the fixed iron core 13.
0 and the biasing spring 41 constitute a second biasing means that applies a mutually acting force to the piston 4 and the plunger 20.

However, since the elastic force of the negative pressure chamber compression spring 5 is set to be larger than that of the energizing spring 41, the elastic force of the energizing spring 41 appears on the plunger 20 side.

Next, the operation of the negative pressure actuator of this embodiment configured as described above will be explained.

First, the basic operation will be explained on the assumption that the rod 40 is fixed to the fixed iron core 13 and the piston 4 is not restrained.

When the coil 12 is de-energized, the plunger 20 is pressed toward the input port 31 by the energizing spring 41,
The poppet valve 23 closes the end of the input port 31 by the biasing force of the valve biasing compression spring 22 . Therefore, since atmospheric pressure is guided to the negative pressure chamber A through the air filter 35 of the air filter head 34, the atmospheric port 32, the communication hole 25, and the output port 33, the piston 4 is moved into the negative pressure chamber A as the first energizing means. The cable 6 connected to the load moves in the direction of arrow a.
Zuru.

Conversely, when the coil 12 is most strongly excited, the attractive force between the fixed iron core 13 and the plungers 1--20 causes the seventh lunge t to resist the urging force of the urging spring 41 of the second urging means.
7-20 moves to the fixed iron core 13 side. At this time, the plunger 20 moves to the left in FIGS. 1 and 2, and the attachment auxiliary member 2 disposed at the end of the plunger 20
1 is in contact with the outer periphery of the poppet valve 23, and the poppet 1-valve 2
3 is moved to the left in the figure, the poppet valve 23 is closed by the inner circumferential surface of the auxiliary attachment member 21 by the urging force of the valve urging compression spring 22, and the atmospheric port 32 is closed. On the other hand, the poppet valve 23 opens the end of the input port 31. Therefore, since the negative pressure source on the input port 31 side increases the negative pressure in the negative pressure chamber A via the output port 33 and the guide pipe 37, the piston 4 resists the biasing force of the compression spring 5 for the negative pressure chamber. and move the cable 6 in the direction opposite to the arrow a.

When the valve body portion is controlled by the current value applied to the coil 12, the attraction force between the fixed core 13 and the plunger 20 causes the plunger to resist the urging force of the urging spring 41 of the second urging means. v-20 moves to the fixed core 13 side,
The auxiliary installation member 21 and the poppet valve 23 are brought into contact and sealed, and the air filter head 34, the atmospheric port 32, and the communication hole 25 are sealed.
The atmospheric pressure that has entered the plunger 20 through the auxiliary mounting member 21 and the poppet valve 23 are sealed against each other, thereby blocking the atmospheric pressure from being introduced into the output port 33 side.

Then, the plunger 20 increases the distance between the input port 31 and the poppet valve 23 in accordance with the magnitude of the excitation current of the coil 12. When the input port 31 and the poppet valve 23 are separated, negative pressure is introduced to the negative pressure chamber A through the output port 33, and in the negative pressure chamber A, the urging force of the negative pressure chamber compression spring 5 of the first urging means is applied. The piston 4 is moved in the opposite direction of the arrow a. At this time, the diaphragm 24 has the output port 3.
The negative pressure on the 3 side and the atmospheric pressure on the atmospheric port 32 side generate a force that moves the attachment auxiliary member 21 to the right in the figure.

That is, the attraction force of the plunger 20 by the coil 12;
When compared with the force acting on the effective diameter of the diaphragm 24 due to the pressure difference between the atmospheric port 32 and the output port 33 and the biasing force of the biasing spring 41 which is the second biasing means, the force acting on the effective diameter of the diaphragm 24 is When the applied force increases, the plunger 20 moves to the right in the figure, and the attachment auxiliary member 21 and the poppet valve 23 also move to the right, and the input port 31 is sealed by the poppet valve 23. The movement of the poppet valve 23 is stopped by sealing the input port 31, but the plunger 20 is further moved to the right by the urging force of the urging spring 41 and the force acting on the effective diameter of the diaphragm 24. Then, the seal between the auxiliary mounting member 21 and the poppet valve 23 is released, and atmospheric pressure flows through the auxiliary mounting member 21 and the poppet valve 2 through the air filter 35, the atmospheric port 32, and the communication hole 25.
3 and is led to the negative pressure chamber A via the output port 33. As a result, when the pressure difference between the output port 33 side and the atmospheric port 32 side decreases, the diaphragm 24
The force acting on the effective diameter of the coil 12 becomes smaller.
Since the suction force of the plunger 20 is greater, the attachment auxiliary member 21 and the poppet valve 23 are brought into contact and sealed state again. When the negative pressure on the output port 33 side decreases, the pressure difference acting around the effective diameter of the diaphragm 24 decreases, so between the poppet valve 23 and the input port 33.
is opened, and negative pressure is introduced into the negative pressure chamber A again through the output port 33.

Therefore, this type of negative pressure actuator has a coil 12
Encouragement! Fixed iron core 13 and plunger 2 by 1ffl flow
0 and the atmospheric port 32 and the output port 33
The negative pressure in the negative pressure chamber A is determined by the force acting on the effective diameter of the diaphragm 24 due to the pressure difference between the diaphragm 24 and the force relationship with the biasing spring 41, which is the second biasing means.

At this time, the acting force of the diaphragm 3 and the movement of the piston 4! J+m, that is, the stroke amount of the cable 6 operates as shown in the characteristic diagram of the negative pressure actuator shown in FIG.

In the explanation of this embodiment so far, the rod 40 and the fixed iron core 1 are
3 is fixed, and the rod 40 does not restrict the movement of the piston 4, but in this case,
As shown in the characteristic diagram of FIG. 3, the negative pressure in the negative pressure chamber A of the negative pressure actuator main body 1 gradually increases, and its acting force changes from pa to pb approximately in proportion to the excitation current of the coil 12. At this time, the stroke amount of the cable 6 at the acting force P2 in the middle becomes Sl. However, the force increases to pb, which is larger than the acting force P2, and then the negative pressure in the negative pressure chamber A becomes Pb,
Even if it is gradually decreased from Pc to pd, the stroke amount of the cable 6 will be 82 (Sl × S2) at the acting force P2, and in order to make the stroke amount 81, the negative pressure in the negative pressure chamber A must be further reduced to Pl. It will have to be lowered. That is, it has hysteresis due to the influence of the load connected to the cable 6, the contact resistance of the movable part, the elasticity of the diaphragm, etc.

As can be seen from FIG. 3, the hysteresis is, for example, only when the acting force is reduced, the internal pressure of the negative pressure chamber A is reduced by the acting force p.
If the negative pressure in the negative pressure chamber A is reduced by the differential pressure corresponding to b and the acting force Pc and applied to the piston 4, the characteristics of the negative pressure actuator of this embodiment will be expressed by Pa and Pb. Similarly, only when increasing the acting force, the internal pressure of the negative pressure chamber A is increased by the differential pressure corresponding to the acting force pb and the acting force pc.
If the negative pressure is increased and applied to the piston 4, the characteristics of the negative pressure actuator of this embodiment will be expressed by Pc and Pd.

Therefore, in this embodiment, the plunger 20 and the piston 4
By sandwiching the rod 40 and the biasing spring 41 as biasing means between them, the following operation can be performed.

As shown in the characteristic diagram of FIG. 3, once the negative pressure in the negative pressure chamber A is increased and the load is displaced in the opposite direction of the arrow a using the cable 6, the piston 4 is returned to its original position. If the second biasing means inserted between the piston 4 and the plunger 20 is compressed by the rod 40, the biasing spring 41 is compressed against the biasing force of the biasing spring 41. is in a state of At this time, the acting force applied to the plunger 20 becomes a force in the right direction in the figure, which is larger than the biasing force of the biasing spring 41 when the piston is at the position where it should originally return.

Therefore, the attraction force of the plunger 20 by the coil 12, the force acting on the effective diameter of the diaphragm 24 due to the pressure difference between the atmospheric port 32 and the output port 33, and the biasing force of the biasing spring 41, which is the second biasing means. The force relationship is such that the biasing force of the biasing spring 41 increases by the amount that the piston 4 is not displaced. When the plunger 20 and the poppet valve 23 are closed, the sealing state between the plunger 20 and the poppet valve 23 is released, and atmospheric pressure is introduced from the atmospheric port 32 to the negative pressure chamber A via the output port 33.

As a result, the negative pressure in the negative pressure chamber A is reduced, and the cable 6 is moved in the direction of arrow a. It is moved to a position where the force acting on the diameter and the biasing force of the biasing spring 41, which is the second biasing means, are balanced.

Also. When piston 4 is moved in the opposite direction to the former,
That is, if the piston 4 stops without returning to the original piston position after reducing the negative pressure in the negative pressure chamber A and displacing the load in the direction of arrow a using the cable 6, then the piston The biasing spring 41 of the second biasing means inserted between the plunger 4 and the plunger 20 is expanded more than the biasing force of the biasing spring 41, which should originally be compressed.

In this way,] the suction force of the plunger 20 by the coil 2, the force acting on the effective diameter of the diaphragm 24 due to the pressure difference between the atmospheric port 32 and the output port 33, and the energizing force which is the second energizing means. The force relationship of the biasing force of the spring 41 is such that the biasing force of the biasing spring 41 becomes smaller by the amount that the piston 4 is not displaced, the appearance is upward, the negative pressure in the negative pressure chamber A becomes small, and the plunge p- 20 and poppet valve 2
3, the poppet valve 23 opens the input port 31, and negative pressure is introduced from the input port 31 to the negative pressure chamber A via the output port 33. As a result, the negative pressure in the negative pressure chamber A increases, and the cable pull 6 is indicated by the arrow a.
The biasing force of the biasing spring 41 is reduced in the direction opposite to the direction shown in FIG.

Therefore, the attraction force of the plunger 20 by the coil 12, the force acting on the effective diameter of the diaphragm 24 due to the pressure difference between the atmospheric port 32 and the output port 33, and the biasing force of the biasing spring 41, which is the second biasing means. The biasing force of the biasing spring 41, which is the second biasing means, may be set so that the balance of forces is equal to the stroke amount by which the position of the piston 4 is displaced due to hysteresis.

If the biasing force of the biasing spring 41 at this time is set so as to obtain the difference in stroke amount shown in FIG. be able to.

In this embodiment, the biasing force of the second biasing means is obtained using a compression spring, but when implementing the present invention, the present invention is not limited to a compression spring, and an extension spring or a compression spring may be used. A tension spring can also be used to function similarly.

Further, in this embodiment, the biasing spring 41 and the rod 40 are used as the second biasing means, but if a guide tube for the biasing spring such as a spring guide is attached to the piston side, only the biasing spring can be used. The function of the second energizing means of the invention can be fulfilled. Of course, the same function can be achieved even if the rod 40 shown in the above embodiment is fixed to the piston 4 side.

However, it is more advantageous for assembly if the rod 40 is not fixed to the piston 4 side.

[Effects of the Invention] As described above, the present invention adjusts the opening degree of the valve body integrally with the negative pressure actuator main body according to the current value.
a second biasing means is sandwiched between a plunger that moves a valve body of the electromagnetic pressure control valve and a piston of the negative pressure actuator body, thereby reducing hysteresis. Since it corrects this, it can be configured without using an electrical control system, and the configuration for correction can be simplified and inexpensive.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a negative pressure actuator according to an embodiment of the present invention, Fig. 2 is an enlarged sectional view of the valve body portion of Fig. 1, and Fig. 3 is a hysteresis characteristic diagram of the negative pressure actuator. . In the figure, 1... Negative pressure actuator main body, 3... Diaphragm, 4... Piston,
DESCRIPTION OF SYMBOLS 10... Electromagnetic pressure control valve, 20... Plunger, 22... Compression spring for valve bias, A... Negative pressure chamber, B... Atmospheric chamber. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A negative pressure chamber and an atmospheric chamber separated by an airtight thin film,
a first energizing means disposed within the negative pressure chamber; a piston that closely responds to the thin film as pressure changes in the negative pressure chamber; and an input port that introduces negative pressure into the negative pressure chamber; A valve element that opens and closes the input port, a plunger that moves the valve element, a coil that drives the plunger by the magnetic force generated by the plunger, and a coil that is held between the plunger and the piston and that moves the valve element. A negative pressure actuator comprising a second energizing means for energizing. (2) The second biasing means held between the plunger and the piston is a rod and a biasing spring that interlock with the piston. Negative pressure actuator.