JPH09217859A - Operation state detecting device for valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide constitution to maintain excellent detecting precision for a long period, in a device to detect the operations state of a valve device having a spring member to energize a valve. SOLUTION: A low retainer 20 and an upper retainer 26 are coupled to a valve element 12. A lower spring 22 to energize upward the lower retainer 20 and an upper spring 26 to energize downward the upper retainer 26 are provided. First and second electromagnetic coils 32 and 36 are disposed above and below a plunger 30 coupled to the valve element 12. The upper spring 26 is magnetized so that a magnetic field H emanates from the interior. A magnetic field detecting sensor 29 is inserted in the upper spring 26. The operation state of the valve element 12 is detected based on the change of the intensity of the magnetic field H occasioned by expansion and contraction of the upper spring 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operating state detecting device for a valve device, and more particularly to an operating state detecting device for detecting an operating state of a valve device having a spring member for urging a valve.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 2-17330.
As disclosed in No. 5, an operating state detecting device for detecting the operating state of a valve device is known. The conventional device described above includes a valve in which a valve shaft and a valve body are integrally formed. A plurality of annular electrodes are formed on the valve shaft of the valve so as to be separated from each other by a predetermined distance in the axial direction. Further, a fixed electrode facing a side surface of the valve shaft is formed on a valve guide that slidably holds the valve shaft of the valve. The plurality of annular electrodes formed on the valve shaft of the valve sequentially approach and separate from the fixed electrode when the valve opens and closes. The conventional device described above converts a change in the relative positional relationship between the fixed electrode and the annular electrode into an electric signal, and detects the operating state of the valve based on the electric signal.

[0003]

However, the above-mentioned conventional device detects the operating state of the valve device by sliding the annular electrode formed on the valve shaft of the valve and the fixed electrode fixed to the valve guide. This is the configuration. According to such a configuration, since wear occurs on the annular electrode and the fixed electrode,
This causes problems such as durability and erroneous detection due to abrasion powder. Further, the structure for forming an electrode on the valve shaft of the valve is
It is difficult to realize at low cost. From this point of view, the above-mentioned conventional device still leaves room for improvement as a device for detecting the operating state of the valve device.

The present invention has been made in view of the above points, and provides an operating state detecting device for a valve device which can detect the operating state of the valve in a non-contact manner and can be realized at low cost. The purpose is to

[0005]

The above object is achieved by the present invention.
As described in (3), a device for detecting the opening / closing characteristics of a valve device including a spring member for urging the valve, and a drive means for generating a driving force acting on the valve in addition to the urging force of the spring member. The magnetic field detecting means for detecting the strength of the magnetic field generated in a predetermined part by magnetizing the spring member and the magnetic field detecting means of the magnetic field detecting means And an operating state detecting means for detecting an operating state.

In the present invention, the valve opens and closes by the balance between the urging force generated by the spring member and the driving force generated by the driving means. When the valve opens and closes, the spring member expands and contracts. The strength of the magnetic field generated in a predetermined portion due to the magnetizing of the spring member, that is, the strength of the magnetic field detected by the magnetic field detecting means, is the same when the spring member is extended and when the spring member is contracted. It changes depending on whether you are there. The operating state detecting means detects the operating state of the valve based on the strength of the magnetic field detected by the magnetic field detecting means.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall configuration diagram of a valve device 10 which is a main part of an operating state detecting device for a valve device according to an embodiment of the present invention. The valve device 10 includes a valve body 12
It has. The valve body 12 is a member disposed in the cylinder head with its lower end exposed in the combustion chamber of the internal combustion engine, and constitutes an intake valve or an exhaust valve of the internal combustion engine. The cylinder head of the internal combustion engine is provided with a port having a valve seat for the valve body 12. When the valve body 12 is separated from the valve seat or seated on the valve seat, the conduction state of the port is controlled.

A valve shaft 14 is fixed to the valve body 12. The valve shaft 14 is held by a valve guide 16 so as to be slidable in the axial direction. The valve guide 16 is supported by the lower cap 17 of the valve drive device 10. Valve shaft 14
A plunger holder 18 is fixed to the upper part of the.
The plunger holder 18 is made of a material having high hardness such as non-magnetic property or low magnetic property such as stainless steel or titanium alloy. The plunger holder 18 includes a cylindrical portion 18a extending in the axial direction of the valve shaft 14 and a cylindrical portion 18a.
And a ring portion 18b formed substantially at the center in the axial direction.

A lower retainer 20 is fixed to the lower end of the plunger holder 18. A lower spring 22 is disposed between the lower retainer 20 and the lower cap 17 to generate an urging force in a direction to separate the lower retainer 20 and the lower cap 17.
The lower spring 22 generates a biasing force that biases the lower retainer 20, that is, the plunger holder 18 upward in FIG. 1.

On the other hand, an upper retainer 24 is fixed to the upper end of the plunger holder 18. The lower end of the upper spring 26 is in contact with the upper portion of the upper retainer. Around the upper spring 26,
A cylindrical upper cap 2 that surrounds the outer circumference
7 are provided. Further, the upper end of the upper spring 26 is in contact with an adjustment bolt 28 screwed to the upper cap 27. Upper spring 26
Generates an urging force that urges the upper retainer 24, that is, the plunger holder 18 downward in FIG.

The upper spring 26 is composed of, for example, a chrome vanadium steel oil temper wire or a carbon steel oil temper wire, and is magnetized so that a magnetic field H directed in a predetermined direction is generated in the vicinity of the central portion thereof. A magnetic field detection sensor 29 gripped by an adjusting bolt 28 is inserted in the center of the upper spring 26. The magnetic field detection sensor 29 is a sensor that generates an electric signal according to the strength of the magnetic field H generated around the magnetic field detection sensor 29, and is realized by, for example, a magnetoresistive element or a Hall element.

As shown in FIG. 1, the magnetic field detection sensor 29 is
When it is inserted into the central portion of the upper spring 26 by a predetermined length, from the magnetic field detection sensor 29, the strength of the magnetic field H generated inside the upper spring 26 and into the upper spring 28 of the magnetic field detection sensor 29. A signal corresponding to the insertion depth of is output. The insertion depth of the magnetic field detection sensor 29 is adjusted so that the output signal of the magnetic detection sensor 29 in the initial state has a predetermined value.

The ring portion 18b of the plunger holder 18
A plunger 30 is joined to the outer periphery of the. The plunger 30 is a doughnut-shaped member made of a soft magnetic material having Fe, Ni, Co or the like as a base material. The plunger 30 and the plunger holder 18 are joined by a method such as electron beam welding, laser welding, brazing, caulking, or bonding.

In the plunger 30, as shown in FIG. 1, the inner peripheral side end 30a and the outer peripheral side end 30b joined to the plunger holder 18 have the same plate thickness.
It is formed to be thinner than the plate thickness of the intermediate portion 30c between the a and the outer peripheral side end portion 30b. Therefore, the plunger 30 has an inner peripheral end 30a at the intermediate portion 30c.
Also, it has a higher magnetic flux circulation capacity than the outer peripheral side end 30b.

A first electromagnetic coil 32 and a first core 34 are arranged above the plunger 30. A second electromagnetic coil 36 and a second core 38 are arranged below the plunger 30. The first core 34 and the second core 38 are both members made of a magnetic material, and have annular grooves 34a and 38a for accommodating the first electromagnetic coil 32 or the second electromagnetic coil 36, respectively, and the plunger holder 18. Through holes 34b and 38b for slidably holding the cylindrical portion 18a.

An outer cylinder 40 is arranged around the outer peripheries of the first core 34 and the second core 38. A state in which the first core 34 and the second core 38 hold the first electromagnetic coil 32 and the second electromagnetic coil 36 in the annular grooves 34a, 38a, and hold the plunger holder 18 in the through holes 34b, 38b. Thus, the outer cylinder 40 maintains the predetermined positional relationship.

In the present embodiment, in the first core 34, the second core 38, and the plunger 30, the inner peripheral side end portion 30a of the plunger 30 has the annular grooves 34a, 38a of the first core 34 and the second core 38. The outer peripheral side end 30b of the plunger 30 faces the inner peripheral side, and
4 and the annular grooves 34a and 38a of the second core 34 are designed to face the outer peripheral side. Furthermore, the first core 34
The taper surfaces 34c, 34d; 38c, 38 are provided on the outer peripheral side end and the inner peripheral side end of the second core 38, respectively.
d is formed.

The upper cap 27 described above is fixed to the upper end surface of the first core 34. The lower cap 17 described above is fixed to the lower end surface of the second core 38. The adjuster bolt 28 described above is adjusted so that the neutral position of the plunger 30 is at the midpoint between the first core 34 and the second core 38.

In the valve drive device 10 having the above structure, the first
When a current is passed through the electromagnetic coil 32 to generate a magnetic field that circulates on the inner peripheral side and the outer peripheral side thereof, the first core 34, the plunger 30, and the air gap between the first core 34 and the plunger 30 are included. Magnetic flux flows through the magnetic circuit. Such a magnetic flux generates an attractive force that attracts the plunger 30 toward the first core 34, that is, an attractive force that displaces the valve body 12 upward in FIG.

When the above-mentioned suction force acts on the plunger 30, the plunger 30, the plunger holder 18, the upper retainer 24, the lower retainer 20, the valve shaft 14 and the valve body 12 resist the urging force of the upper spring 26. It is displaced upward in 1. Then, the displacement is continued until the plunger 30 substantially contacts the first core 34. Hereinafter, the position of the plunger 30 under such a condition will be referred to as a valve closing side displacement end.

When the current supplied to the first electromagnetic coil 32 is cut off from the state in which the plunger 30 is held at the valve closing side displacement end, the electromagnetic attraction force acting on the plunger 30 disappears, Due to the biasing force of the upper spring 26, the plunger 30 starts to be displaced downward in FIG. When an appropriate current is passed through the second electromagnetic coil 36 at the time when the displacement amount of the plunger 30 reaches a predetermined value, the attraction force for attracting the plunger 30 to the second core 38 side, that is, the valve body 12 is removed. In FIG. 1, a suction force that displaces downward is generated.

When the suction force acts on the plunger 30, the plunger 30, the plunger holder 18, the upper retainer 24, the lower retainer 20, the valve shaft 14 and the valve body 12 resist the urging force of the lower spring 22. The plunger 30 is displaced downward substantially in FIG. 1 until it comes into contact with the second core 38. Hereinafter, the position where the plunger 30 contacts the second core 38 is referred to as the valve-opening side displacement end. Therefore, according to the valve device 30, current is alternately supplied to the first electromagnetic coil 32 and the second electromagnetic coil 36 at appropriate timing, so that the plunger 30 is moved to the valve closing side displacing end and the valve opening side displacing end. It is possible to reciprocate between the two, that is, to reciprocate the valve body 12 between the valve opening position and the valve closing position.

In the present embodiment, the distance between the neutral position of the plunger 30 and the valve closing side displacement end and the distance between the neutral position and the valve opening side displacement end are both set to ΔL. Further, the upper spring 26 is arranged in the valve device 10 so that the entire length thereof becomes L when the plunger 30 is in the neutral position. Therefore, in the process in which the plunger 30 reciprocates between the valve closing side displacement end and the valve opening side displacement end, the total length of the upper spring 26 is “L + ΔL” and “L”.
-Expansion / contraction with ΔL ".

As described above, the upper spring 26 is magnetized so that the magnetic field H is generated therein. The strength of the magnetic field H is strengthened when the upper spring 26 is contracted, and is weakened when the upper spring 26 is expanded. Therefore, the magnetic field detection sensor 2
In Fig. 9, a larger magnetic field H is detected as the plunger 30 is closer to the valve closing side displacement end, and a smaller magnetic field H is detected as the plunger 30 is closer to the valve opening side displacement end.

In the operation state detecting device of this embodiment, the signal output from the magnetic field detecting sensor 29 when the valve device 10 is stopped is used as a reference signal, and the magnetic field detecting sensor 29 outputs the signal during the operation of the valve device 10. It is determined that the plunger 30 has passed the neutral position when the reference signal is output. When the output signal of the magnetic field detection sensor 29 has the maximum value, it is determined that the plunger 30 is located at the valve closing side displacement end, and when the output signal has the minimum value, the plunger 30 opens the valve. It is judged that it is located at the side displacement end.

FIG. 2 is a block diagram showing the contents of control performed on the valve device 10. In the present embodiment, the controller 42 shown in FIG. 2 is connected to the magnetic field detection sensor 29 included in the valve device 10. In addition, the controller 42 is connected to the first device of the valve device 10 via a drive circuit.
The electromagnetic coil 32 and the second electromagnetic coil 36 are connected.

The controller 42 uses the magnetic field detection sensor 29.
The operating state of the plunger 30, that is, the displacement and displacement speed of the plunger 30 is detected based on the output signal of Further, the controller 42, based on the detected operating state of the plunger 30, feed-forward control (F / F control) and feedback control (F / B) to match the actual operating state of the valve body 12 with the target operating state. Control) is performed, and the electric signal obtained as a result is supplied to the drive circuits of the first electromagnetic coil 32 and the second electromagnetic coil 36.

The electric signal supplied to the drive circuit is converted into magnetic energy in the first electromagnetic coil 32 and the second electromagnetic coil 36, and an attractive force acting on the plunger 30 is generated. As a result, the magnetic energy is converted into mechanical motion, and the operating state of the valve device 10 is controlled so as to approach the target operating state.

As described above, in the valve device 10,
A mechanism for outputting a signal according to the operating state of the plunger 30 can be realized only by magnetizing the upper spring 26 and inserting the magnetic field detection sensor 29 inside the upper spring 26. Therefore, according to the configuration of this embodiment, the operating state of the plunger 30, that is, the valve body 12
A mechanism for accurately detecting the operating state of can be realized at low cost.

Further, in this embodiment, by using the magnetic field detecting sensor 29, it is possible to detect the operating state of the plunger 30 in a non-contact manner. Therefore, according to the configuration of the present embodiment, there is no possibility of erroneous detection due to abrasion powder or the like, and excellent detection accuracy can be maintained for a long period of time. As described above, according to the configuration of the present embodiment, it is possible to inexpensively realize the operating state detection device of the valve device, which is excellent in durability.

In the above embodiment, the upper spring 26 is the spring member according to claim 1, and the plunger 30, the first electromagnetic coil 32, and the first core 34 are the driving means according to claim 1. The magnetic field detection sensor 29 corresponds to the magnetic field detection means described in claim 1, and the controller 42 corresponds to the operating state detection means described in claim 1.

In the above embodiment, the driving force acting on the valve body 12 is generated by the first electromagnetic coil 32 and the second electromagnetic coil 36.
The present invention is not limited to this, and for example, the driving force may be generated by a cam mechanism that operates in conjunction with the crankshaft of the internal combustion engine. Further, in the above embodiment, the valve device 10 is used as the intake valve or the exhaust valve of the internal combustion engine, but the use of the valve device 10 is not limited to this.

[0033]

As described above, according to the present invention, the operating state of the valve can be detected in a non-contact manner on the basis of the magnetic field strength of a predetermined portion. Further, the configuration of the present invention can be realized only by magnetizing the spring member originally included in the valve device and additionally adding the magnetic field detecting means. Therefore, according to the present invention, an operating state detection device of a valve device excellent in durability capable of maintaining high detection accuracy for a long time,
It can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a valve device that is a main part of an operating state detection device that is an embodiment of the present invention.

FIG. 2 is a block diagram showing the contents of control executed in the operating state detecting device according to the embodiment of the present invention.

[Explanation of symbols]

 10 Valve device 12 Valve body 26 Upper spring 28 Adjust bolt 29 Magnetic field detection sensor 30 Plunger 32 First electromagnetic coil 34 First core 36 Second electromagnetic coil 38 Second core 42 Controller

Claims (1)

[Claims] 1. A device for detecting an opening / closing characteristic of a valve device, comprising: a spring member for urging a valve; and a drive means for generating a driving force acting on the valve in addition to the urging force of the spring member. A magnetic field detecting means for detecting the strength of a magnetic field generated in a predetermined part by magnetizing the spring member, and the spring member being magnetized; An operating state detecting device for detecting an operating state, and an operating state detecting device for a valve device, comprising: