JPH11241668A - Step motor flow control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of parts and assembling working man-hour, improve control accuracy, prevent wear of a screw part, and further, increase a step motor scale and increase consumption current in a step motor flow control valve in which a valve seat forming a valve hole leading to a first passage and a valve chamber leading to a second passage are provided on a valve housing, one end part of a valve shaft whose revolution around a shaft line is prevented is screwed onto a rotor of a step motor and the other end part of the valve shaft is connected with a valve part which can be seated in the valve seat. SOLUTION: At the other end part of a bellows 281 which coaxially surrounds a valve shaft 271 because one end part is fixed to a valve housing 5 and is capable of elongating and contracting in the shaft line direction of the valve shaft 271 , a valve part 36 is integrally formed. The other end part of the valve shaft 271 is connected so that at least a shaft direction relative moving may be impossible. Between the outside face of the valve shaft 271 and the inside face of the bellows 281 , an annular communicating chamber 37 leading to a valve hole 34 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step motor type flow control valve, and more particularly, to a first passage, a second passage, a valve seat forming a valve hole communicating with the first passage, and a valve seat facing the valve seat. A valve chamber communicating with the second passage is provided in the valve housing, and one end of a valve shaft, which is prevented from rotating around an axis, is screwed to a rotor of a step motor fixed to the valve housing, and seats on the valve seat. The present invention relates to a step motor type flow control valve in which the other end of a valve shaft is connected to a valve portion housed in a valve chamber.

[0002]

2. Description of the Related Art Conventionally, a flow control valve for converting the rotational movement of a step motor into the axial movement of a valve body is already known, for example, from Japanese Patent Application Laid-Open No. H4-50566. A valve shaft, which is prevented from rotating around the rotation axis of the rotor, is screwed to a rotor shaft connected to the rotor of the stepping motor, and a valve portion supported to be able to advance and retreat to the valve holder, between the valve holder. A spring that exerts a spring force in a direction in which the valve portion is seated on the valve seat is provided.

[0003]

However, in the above-mentioned prior art, the fluid pressure difference between the first and second passages acts on the valve portion, and when the fluid pressure difference fluctuates,
The balance between the driving force acting on the valve portion from the step motor and the fluid pressure difference acting on the valve portion may be lost, and the position control accuracy of the valve portion may be reduced. When the fluid pressure on the first passage side is higher than the fluid pressure on the second passage side, a force in the valve opening direction due to the fluid pressure difference acts on the valve portion,
A large load acts on the threaded portion of the rotor shaft and the valve holder, which may cause deterioration of controllability or wear of the threaded portion. When the pressure is larger than the pressure, the force in the valve closing direction due to the fluid pressure difference acts on the valve portion, and the drive only opens the valve portion by overcoming the force in the valve closing direction due to the fluid pressure difference. Since the force needs to be exerted by the step motor, there is a possibility that the size of the step motor is increased and current consumption is increased.

Further, when the diameter of the valve hole is increased in order to increase the flow rate when the valve is opened, the diameter of the valve portion also increases, and the force acting on the valve portion based on the fluid pressure difference further increases. It is difficult to increase the flow rate.

[0005] Further, in the above-mentioned conventional device, the spring for removing the backlash in the threaded portion of the valve holder and the rotor shaft is provided.
Since it is provided between the valve holder and the valve housing, the number of parts is increased and the number of assembling work steps is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and aims to reduce the number of parts and the number of assembling work steps, to improve control accuracy and to improve screw accuracy regardless of the fluid pressure difference between the first and second passages. It is an object of the present invention to provide a step motor type flow control valve capable of preventing abrasion of a portion and further preventing an increase in the size of a step motor and an increase in current consumption.

[0007]

In order to achieve the above object, according to the present invention, a first passage, a second passage, and a first passage are provided.
A valve seat that forms a valve hole communicating with the passage, and a valve chamber facing the valve seat and communicating with the second passage are provided in the valve housing, and the rotation of the step motor rotor fixed to the valve housing rotates around the axis. In a step motor type flow control valve, one end of a blocked valve shaft is screwed, and the other end of the valve shaft is connected to a valve portion accommodated in the valve chamber so as to be seated on the valve seat. A portion is fixed to the valve housing, coaxially surrounds the valve shaft, and a valve portion is integrally formed at the other end of the bellows which can expand and contract in the axial direction of the valve shaft, and the other end of the valve shaft is at least An annular communication chamber is formed between the outer surface of the valve shaft and the inner surface of the bellows, the annular communication chamber communicating with the valve hole.

According to the construction of the first aspect of the present invention, the valve portion is integrally formed with the other end of the bellows having one end fixed to the valve housing, and the valve shaft is connected to the bellows. A communication chamber communicating with the first passage through the valve hole is formed in the inside, so that the force acting on the valve portion due to the fluid pressure difference between the first and second passages can be reduced, and the fluid pressure difference is reduced. Even if it fluctuates, the balance between the driving force acting on the valve portion from the stepping motor and the difference in fluid pressure acting on the valve portion is prevented from being largely disturbed, so that the control accuracy can be improved. Further, by preventing a large load from acting on the threaded portion of the valve shaft and the rotor, the wear of the threaded portion can be suppressed, and the increase in the size of the step motor and the increase in current consumption can be avoided. Moreover, even if the diameters of the valve hole and the valve portion are increased in order to increase the flow rate, the force acting on the valve portion based on the fluid pressure difference does not greatly increase, and therefore the flow rate can be easily increased. Also, due to the elasticity of the bellows,
Since the backlash in the threaded portion between the valve shaft and the rotor can be absorbed, a spring for backlash is not required, and the number of parts can be reduced, and the number of assembling work steps is reduced. be able to.

The invention according to claim 2 is the same as the above-described claim 1.
In addition to the configuration of the invention described in the above, one end of the bellows made of a synthetic resin is integrally provided with a flange portion extending outward in a radial direction of the bellows, and a motor housing of a step motor is provided with a valve. According to such a configuration, the flange portion has a function of sealing between the valve chamber and the outside, so that the valve housing is held between the valve housing and the valve housing. It is not necessary to provide a seal member between the bellows, or between the motor housing and the valve housing of the step motor, so that the number of parts can be reduced by that much, and the work for assembling the seal member becomes unnecessary. It is possible to reduce the number of attachment work steps.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, one end of the valve shaft is disabling relative rotation about an axis to the other end of the bellows. According to such a configuration, the rotation about the axis of the valve shaft is prevented by the bellows, and the structure only for preventing the rotation about the axis of the valve shaft is unnecessary. And the configuration around the valve stem can be simplified.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 and 2 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a flow control valve, and FIG. 2 is a sectional view taken along line 2-2 of FIG.

First, in FIG. 1, this flow control valve is for controlling the amount of idle air in an intake system of an engine, for example.
Is concluded.

The valve housing 5 has a first open end.
A hole 7, a second hole 8 having a diameter smaller than the first hole 7 and one end coaxially connected to the other end of the first hole 7, and a second hole 8 having a diameter smaller than the second hole 8 and one end connected to the other end of the second hole 8; Are coaxially connected to each other, a fourth hole 10 having a smaller diameter than the third hole 9 and one end coaxially connected to the other end of the third hole 9, and a fourth hole 10 having a smaller diameter than the fourth hole 10.
The other end of the hole 10 is provided with a fifth hole 11 having one end coaxially connected and the other end closed. The valve housing 5 is provided with a passage hole 12 communicating with an intake passage on the upstream side of the throttle valve in the throttle body 6 so as to open to the inner surface of the fifth hole 11.
The first passage 13 is formed by the passage hole 12 and the intake passage upstream of the throttle valve. Further, a second passage 14 communicating with the intake passage downstream of the throttle valve is provided in the valve housing 5 so as to open to the inner surface of the fourth hole 10.

A step motor 15 is provided in the valve housing 5.
₁ is mounted, the step motor 15 _1, since those of conventionally known in detail about the structure will not be described, the rotor 17 having the permanent magnets 16 on the outer peripheral surface
And a pair of stators 18 and 19 fixedly arranged with a small gap between the outer circumferential surface of the rotor 17 and adjacent to each other in the axial direction. A ball bearing 21 is interposed between one end of the rotor 17 and one end of the mold portion 20.

One end of the mold section 20 is covered with a synthetic resin cover 23 integrally provided with a coupler section 23a having a connection terminal 22 connected to the coils 18a and 19a of the stators 18 and 19 facing inside. . The motor housing 24 of the step motor 15 ₁ is formed in a cylindrical shape, caulked portion 24a which engages with the cover 23 fitted to one end portion of the motor housing 24 is provided at one end of the motor housing 24, An annular seal member 39 that is in close contact with the inner peripheral surface of the motor housing 24 is mounted on the outer peripheral surface of the cover 23. At the other end of the motor housing 24, the mold portion 20
An engaging flange 24b that engages with the other end of the first member is integrally provided.

[0017] Such a step motor 15 _1, the first valve housing 5 and the other end of the motor housing 24
It is fixed to the valve housing 5 by being pressed into the hole 7.

[0018] The step motor 15 ₁ of the rotor 17,
As has rotation axis coaxial with the screw hole 25 is provided, the male screw portion 26 provided at one end portion outer surface of the valve shaft 27 ₁ is disposed in the rotor 17 coaxially is screwed into the screw hole 25. Moreover the valve shaft 27 ₁ is adapted to penetrate the support cylindrical portion 20a which is formed integrally with the other end portion of the molded portion 20 in the step motor 15 _1, as shown in Figure 2,
Inner shape of the support cylinder portion 20a is formed to have a cross-sectional shape of substantially oval, the valve shaft 27 ₁ of the outer contour in section passing through the supporting tube portion 20a also correspond to the inner surface shape of the support tube portion 20a It is formed to have a substantially oval cross-sectional shape. That is prevented from rotating about the axis but will be one end of the valve shaft 27 ₁ through the supporting tube portion 20a so as to be allowed to move in the axial direction is screwed to the rotor 17, the rotor 17 the valve shaft 27 ₁ is moved in the axial direction in response to rotation.

The valve shaft 27 ₁ of the other end portion is connected to the bellows 28 _1. The bellows 28 _1, the bellows portion 28a surrounding the valve shaft 27 ₁ extending in the axial direction of the valve shaft 27 ₁ coaxially
And a ring portion 28b coaxially connected to one end of the bellows portion 28a.
A flange portion 28c extending radially outward from the ring portion 28b; and an end plate portion 28d connected to the other end of the bellows portion 28a so as to close the other end of the bellows portion 28a. , Made of synthetic resin. Moreover, the bellows 2
8 ₁ is an annular stepped portion 29 formed between the second and third holes 8 and 9 of the valve housing 5, and a motor press-fitted into the first hole 7 of the valve housing 5 and fixed to the valve housing 5. The inner surface of the third hole 9 and the bellows 28 are sandwiched between the housing 24 and the valve housing 5.
_A valve chamber 30 communicating with the second passage 14 is formed between the outer surfaces ₁ .

The end plate 28d of the bellows 28 ₁
A connection hole 31 is provided at the center of the valve shaft 27.
The other end of ₁ is press-fitted into the connection hole 31. This allows
The other end of the valve shaft 27 _1, will be connected to the other end of the bellows 28 ₁ axial relative movement and axial relative rotation around together as impossible.

In the valve housing 5, a ring-shaped valve seat member 33 is press-fitted into the fourth hole 10 so as to be received by an annular step 32 formed between the fourth and fifth holes 10,11. are, on the inner peripheral side of the bellows 28 ₁ end of the valve seat member 33, a valve seat 35 formed by rubber or the like to form a valve hole 34 communicating with the first passage 13 is secured. An annular valve portion 36 which can be seated on the valve seat 35 to shut off the space between the first passage 13 and the valve chamber 30 is provided with a bellows 28.
_One end is formed integrally with the outer periphery of the end plate 28d.

Moreover, the end plate 28d of the bellows 28 ₁
In order to always communicate with the valve hole 34, an annular communication chamber 37 formed between the valve shaft 27 ₁ and the bellows 28 ₁ is connected.
Alternatively, a plurality of communication holes 38 are provided.

Next, to explain the action of this embodiment, the valve shaft 27 ₁ is the axial direction together with the valve unit 36 to the other end of the bellows 28 ₁ one end is fixed to the valve housing 5 is formed integrally is connected as a disable relative rotation relative movement and axial around the bellows 28 _1, the communication chamber 37 communicating with the first passage 13 through the valve hole 34 is formed. Therefore, it is possible to reduce the force acting on the valve portion 36 due to the fluid pressure difference between the first and second passages 13 and 14 when the valve portion 36 is seated on the valve seat 35.

[0024] Thus without balance collapses large fluid pressure differential acting on the driving force and the valve portion 36 of the fluid pressure difference acts on the valve portion 36 from the step motor 15 ₁ is also varied, to enhance the accuracy of the control Can be. Also as there is no act large load on the threaded portion of the valve shaft 27 ₁ and the rotor 17, avoiding it is possible to suppress the wear of the threaded portion, the increase in the size and current consumption of the step motor 15 ₁ can do.

Even if the diameters of the valve hole 34 and the valve portion 36 are increased in order to further increase the flow rate, the force acting on the valve portion 36 based on the fluid pressure difference does not greatly increase.
Therefore, the flow rate can be easily increased.

[0026] Moreover by the elastic force bellows 28 ₁ exerts, it is possible to absorb the backlash in the meshing portion of the valve shaft 27 ₁ and the rotor 17, the spring for the backlash removal is not required, the number of parts Can be reduced, and the number of assembly work steps can be reduced.

Furthermore flange portion 28c formed integrally with one end of the bellows 28 ₁ made of synthetic resin, a motor housing 24 of the step motor 15 _1, the valve housing 5
Of the valve chamber 30, the function of sealing between the inside and the outside of the valve chamber 30 is performed by the flange portion 28c. Therefore, the valve housing 5 and the bellows 28
Between ₁ or it is not necessary to provide a seal member between the motor housing 24 and the valve housing 5, it is possible to reduce the amount corresponding parts, assembling work for assembling the sealing member as required The number of steps can be reduced.

3 and 4 show a second embodiment of the present invention. FIG. 3 is a longitudinal sectional view of the flow control valve, and FIG. 4 is a sectional view taken along line 4-4 of FIG.

The valve is molded portion 20 'of the step motor 15 ₂ partially be pressed into the motor housing 24 to the first hole 7 of the housing 5, the valve shaft 27 ₂ Shi allowed slidably through paint cylindrical The support cylinder 20a 'is provided integrally. The supporting tube portion 20a 'are those having a circular cross sectional shape, the support tube portion 20a' the outer surface of the valve shaft 27 ₂ at the portion corresponding to the also formed to have a simple circular cross-section.

The valve between the step portion 29 and the motor housing 24 of the housing 5, one end side of the flange portion 28c of the bellows 28 ₂ are held between the end plate portion to which the bellows 28 ₂ is provided on the other end the 'coupling hole 31 provided in the center of the' 28d, the other end of the valve shaft 27 ₂ is connected as non-relative rotation about the axis. That is, as shown in Figure 4, the coupling hole 31 'is formed in a substantially oval shape, the coupling hole 31 in the valve shaft 27 _2' substantially oval corresponding to the inner surface shape of the portion also connecting hole 31 'to be inserted into It is formed so as to have an outer surface shape of

[0031] The valve shaft 27 _2, an annular engagement projection 40 for engaging the inner surface of the end plate portion 28d 'is integrally provided, projecting the valve shaft 27 ₂ from the end plate portion 28d An end plate portion 2 is provided between a caulking portion 41 formed by caulking so that an end thereof is engaged with an outer surface of the end plate portion 28d 'and the engaging projection 40.
By 8d is held, the other end of the valve shaft 27 ₂ is connected to the other end of the bellows 28 ₂ as non relative axial movement.

[0032] In the second embodiment, by the rotation about the axis of the valve shaft 27 ₂ to be blocked by the bellows 28 _2, it does not have a detent function to the step motor 15 _{and second} supporting tube portion 20a 'structure It has become. Thereby, the valve shaft 27
The structure just to prevent the rotation around the _second axis can be eliminated, it is possible to simplify the structure around the valve shaft 27 _2. Moreover 'because it is sufficient the valve shaft 27 ₂ at the portion corresponding to the one having a simple circular cross-sectional shape, the support tube portion 20a' supporting tube portion 20a the valve shaft by 27 ₂
Can be improved, and the control accuracy can be further improved.

By the way, in the second embodiment may be pressed into the other end of the valve shaft 27 ₂ the bellows 28 _{and second} end plate portion 28d '.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the above-described embodiment, the case where the present invention is applied to the flow control valve for controlling the amount of idle air in the intake system of the engine has been described. It can be widely implemented as a valve.

In the above embodiment, the first passage 13 is described as being on the upstream side and the second passage 14 is on the downstream side. However, the first passage 13 may be on the downstream side and the second passage 14 may be on the upstream side.

Furthermore bellows 28 _1, 28 ₂ of the end plate portion 2
8d and 28d 'are provided with communication holes 38 communicating between the valve hole 34 and the communication chamber 37. However, if the communication chamber 37 communicates with the valve hole 34, the arrangement of the communication holes 38 is changed to the end plate. It is not necessary to be limited to the portions 28d and 28d ', a communication hole may be provided in the valve shaft, and a passage for connecting the communication chamber 37 to the valve hole 34 is formed between the end plate portion and the valve shaft. It may be.

[0038]

As described above, according to the first aspect of the present invention, the force acting on the valve portion due to the fluid pressure difference between the first and second passages is suppressed to improve the control accuracy. Therefore, it is possible to avoid an increase in the size of the step motor and an increase in current consumption, and it is possible to easily increase the flow rate without increasing the force acting on the valve even if the diameter of the valve hole and the valve is increased. Can be increased,
Further, since a spring for rattling is not required, the number of parts and the number of assembling work steps can be reduced.

According to the second aspect of the present invention, it is not necessary to provide a seal member between the valve housing and the bellows or between the motor housing and the valve housing of the step motor, so that the number of parts can be reduced. The number of assembling work steps can be reduced.

Further, according to the third aspect of the present invention, the rotation of the valve shaft around the axis is prevented by the bellows, and the structure only for preventing the rotation of the valve shaft around the axis is not required. Can be simplified.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a flow control valve according to a first embodiment.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a longitudinal sectional view of a flow control valve according to a second embodiment.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

[Explanation of symbols]

5: Valve housing 13: First passage 14: Two-way passage 15 ₁ , 15 ₂ ... Step motor 17 ... Rotor 24 ... Motor housing 27 ₁ , 27 ₂ ... Valve Shafts 28 ₁ , 28 ₂ ... bellows 28 c ... flange portion 30 ... valve chamber 34 ... valve hole 35 ... valve seat 36 ... valve portion 37 ... communication chamber

Claims (3)

[Claims] A first passage (13), a second passage (14),
A valve seat forming a valve hole (34) communicating with the first passage (13)
(35), and the second through the valve seat (35).
The valve chamber (30) leading to the passage (14) is a valve housing (5).
And fixed to the valve housing (5)
Motor (15₁, 15_Two) To the rotor (17)
The valve shaft (27₁, 27_TwoOne end
Parts are screwed together to allow seating on the valve seat (35)
A valve shaft (27) is attached to a valve portion (36) housed in the valve chamber (30).
₁, 27_TwoStep motor type flow with the other end connected
One end of the quantity control valve is fixed to the valve housing (5).
The valve shaft (27₁, 27_Two) Is coaxially surrounded
The valve shaft (27₁, 27_Two)
Rose (28₁, 28_TwoThe other end of () has a valve (36)
The valve shaft (27₁, 27_Two)of
The other end is connected so that at least relative axial movement is impossible.
And the valve shaft (27₁, 27_Two) Outer surface and bellows (2)
8₁, 28 _Two) Between the inner surfaces of the valve holes (34)
An annular communication chamber (37) is formed.
Step motor type flow control valve. 2. The bellows (2) made of a synthetic resin.
8 _1, one end of the 28 _2), a flange portion out radially outward Zhang of the bellows (28) (28c) is integrally provided with a motor housing of the step motor (15 _1, 15 ₂₎ (24) The step motor type flow control valve according to claim 1, wherein the flange portion (28c) is fixed to the valve housing (5) by sandwiching the flange portion (28c) between the flange portion (28c) and the valve housing (5). 3. The other end of the valve shaft (27 ₁ , 27 ₂ ) is connected to the other end of the bellows (28 ₁ , 28 ₂ ) so that relative rotation around an axis is impossible. The step motor type flow control valve according to claim 1 or 2, wherein