JP2000180304A - Engine valve displacement measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fasten a core to a spring retainer reliably with sufficient joining strength. SOLUTION: In a device for measuring displacements of an engine valve, displacements of an engine valve 2 are measured by a differential transmformer- type displacement sensor 12. The displacement sensor 12 is formed of a bobbin 14 and a tubular core 15. The bobbin 14 is fastened to a cylinder head 3 concentrically with the engine valve 2, and a sensor coil 13 formed of a primary coil and secondary coil is wound on the peripheral surface of the bobbin 14. The tubular core 15 is movable inside the bobbin 14, and the upper end part of the core 15 is mounted on a spring retainer 6. In this case, an outward directed flange part 15a is provided at the upper end part of the core 15, and the flange part 15a and the inner surface of the upper part of the core 15 are adhered to the lower surface of the spring retainer 6 inner than the part for receiving and stopping a valve spring 8 and the peripheral surface of the tubular part of the spring retainer 6 connected to the lower surface by an adhesive 21, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the displacement of an engine valve incorporated in a valve train of an internal combustion engine in a firing state of an actual engine.

[0002]

2. Description of the Related Art When the specifications of the components of a valve train are changed, the actual displacement (momentum) of an engine valve (hereinafter abbreviated as "valve") is measured, and the valve train components are measured based on the movement characteristics. May be evaluated or the followability of the valve to the cam may be examined.

[0003] This measurement is usually performed by detecting the axial displacement of a valve or a valve operating component (such as a spring retainer) that moves integrally with the valve by a proximity sensor or the like. For direct-acting valve trains in which the shaft end and spring retainer are covered by a cap-shaped tappet, or in small engines with little space around the valve train, the displacement of the valve can be detected directly. It can be difficult.

[0004] Therefore, in the direct-acting type valve operating mechanism, the piston and the connecting rod are removed from the cylinder block, a proximity sensor or the like is provided immediately below the valve in the cylinder, and the engine is operated (motored) on a table. In this manner, the axial displacement of the valve is measured from the front of the umbrella.

[0005] In the measurement by driving on such a table,
It does not measure the actual displacement of the valve while the engine is in firing operation, so it accurately measures the effects of the combustion pressure in the cylinder and the back pressure of the exhaust system on the valve behavior. Can not do it.

Accordingly, the present applicant has developed a small device capable of measuring the actual displacement of the valve during the firing operation of the engine with high accuracy regardless of the type of the valve operating mechanism, and has already filed a patent application. (See Japanese Patent Application Laid-Open No. 9-61302).

[0007]

In the measuring device of the prior application, a differential transformer type displacement sensor is provided in an annular space between a valve and a valve spring, and its primary and secondary coils are wound. The displacement of the valve is detected by the vertical movement of the cylindrical core fixed to the lower surface of the spring retainer in the bobbin, but the following danger may be considered.

That is, since the core in the measuring device of the prior application merely press-fits the upper end of the core to the lower surface of the spring retainer, the core is vibrated by the opening and closing movement of the valve.
The core may fall off.

In order to prevent this, the core may be fixed to the spring retainer by welding, brazing, or the like, but generally, the core is made of brass, aluminum, SU, or the like.
Since the spring retainer is formed of a non-magnetic material such as S304 and the like, and the spring retainer is formed of cast steel or the like in order to secure load resistance or the like, the difference in material composition between the two causes
The heat bonding property is not always good, and the required sufficient bonding strength cannot be obtained.

[0010] The present invention has been made in view of the above problems, and by firmly joining a core and a spring retainer with sufficient joining strength, the core is prevented from falling off due to vibration during operation. It is another object of the present invention to provide an engine valve displacement measuring device capable of greatly improving durability.

[0011]

According to the present invention, the above-mentioned problem is solved as follows. (1) Displacement of an engine valve is concentrically fixed to an engine valve on a cylinder head or an immovable member integrally formed with the cylinder head, and a sensor coil including a primary coil and a secondary coil is wound around an outer peripheral surface of the bobbin. And an upper and lower end of the bobbin can be moved up and down by a differential transformer type displacement sensor having a cylindrical core attached to a spring retainer. An outward flange is provided at the upper end of the core, and the flange and the inner surface of the upper end of the core are
Each is fixed to the lower surface of the spring retainer inwardly of the valve spring receiving portion and the outer peripheral surface of the cylindrical portion connected thereto with an adhesive.

(2) In the above item (1), the outward flange portion of the core is formed by using an adhesive and a plurality of screws.
Secure to the spring retainer.

(3) Displacement of the engine valve is concentrically fixed to the cylinder head or a stationary member integral therewith with the engine valve, and a sensor coil composed of a primary coil and a secondary coil is wound around the outer peripheral surface. Displacement of an engine valve which is configured to be able to move up and down in the bobbin, and to be detected by a differential transformer type displacement sensor having an upper end portion having a cylindrical core attached to a spring retainer. In the measuring device, the upper end of the core is press-fitted into the outer peripheral surface of the cylindrical portion of the spring retainer over a required length.

(4) In the above item (3), the upper end of the core is caulked by plastically deforming the portion of the lower surface of the spring retainer that contacts the upper end of the core in the radially-reducing direction.

(5) In the above item (3), a concave groove is formed in the outer peripheral surface of the cylindrical portion of the spring retainer, and the outer peripheral surface of the core in a portion facing the concave groove is plastically deformed into the concave groove. Caulking.

(6) Displacement of the engine valve is concentrically fixed to the cylinder valve or a stationary member integral therewith with the engine valve, and a sensor coil composed of a primary coil and a secondary coil is wound around the outer peripheral surface. Displacement of an engine valve which is configured to be able to move up and down in the bobbin, and to be detected by a differential transformer type displacement sensor having an upper end portion having a cylindrical core attached to a spring retainer. In the measuring device, the core is formed integrally with a spring retainer formed of a non-magnetic material.

(7) Displacement of the engine valve is concentrically fixed to the cylinder head or an immovable member integral therewith with the engine valve, and a sensor coil composed of a primary coil and a secondary coil is wound around the outer peripheral surface. Displacement of an engine valve which is configured to be able to move up and down in the bobbin, and to be detected by a differential transformer type displacement sensor having an upper end portion having a cylindrical core attached to a spring retainer. In the measuring device, a large-diameter outward flange portion is provided at an upper end portion of the core, and the outward flange portion is fixedly held by being pressed between the lower surface of the spring retainer and the upper end of the valve spring.

(8) Displacement of the engine valve is concentrically fixed to the cylinder head or a stationary member integral therewith with the engine valve, and a sensor coil composed of a primary coil and a secondary coil is wound around the outer peripheral surface. Displacement of an engine valve which is configured to be able to move up and down in the bobbin, and to be detected by a differential transformer type displacement sensor having an upper end portion having a cylindrical core attached to a spring retainer. In the measuring device, a screw portion for forming the core on the inner surface of the upper end portion is screwed to a male screw portion formed on the outer peripheral surface of the cylindrical portion of the spring retainer, so that the core is integrally fixed to the spring retainer.

(9) Displacement of the engine valve is concentrically fixed to the cylinder head or an immovable member integral therewith with the engine valve, and a sensor coil composed of a primary coil and a secondary coil is wound around the outer peripheral surface. Displacement of an engine valve which is configured to be able to move up and down in the bobbin, and to be detected by a differential transformer type displacement sensor having an upper end portion having a cylindrical core attached to a spring retainer. In the measurement device, a plurality of upwardly-facing mounting pieces are protruded from the upper end of the core, and the mounting pieces are inserted from below into insertion holes formed in the spring retainer, and the protruding ends are bent outward. Thereby, the core is fixed to the spring retainer.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a displacement measuring device for an engine valve according to the present invention will be described below with reference to the drawings. 1 and 2 show a main part of a direct-acting type valve train (1) to which the invention of claim 1 is applied.

As shown in FIG. 1, the shaft (2a) of the valve (2)
Is the valve guide (4) press-fitted into the cylinder head (3)
By this, it is slidably guided in the vertical direction, and this shaft part (2a)
A spring retainer (6) is attached to an upper end portion of the via a cotter (5) (5) having a half-split cylindrical shape. A coil-shaped valve spring is provided between the spring retainer (6) and the washer (7) placed on the upper surface of the cylinder head (3).
(8) is reduced.

The valve spring (8) is provided with a valve (2).
Is substantially coaxial with the shaft portion (2a), and is disposed so as to surround the valve guide (4) and the shaft portion (2a). The lip seal (9) fitted to the upper end of the valve guide (4) is
The contact with the outer peripheral surface of (2a) prevents oil falling.

A tappet (10) is fitted to the upper end of the shaft (2a) of the valve (2) so as to cover the end of the shaft with the spring retainer (6). A cam (not shown) is in contact with the shim (11) fitted in the concave portion. When this cam rotates, the valve (2) is pushed down against the force of the valve spring (8), and opens and closes.

The shaft (2a) of the valve (2) and the valve guide
In the annular space (A) formed between (4) and the valve spring (8), a high-frequency differential transformer type displacement sensor is provided.
(12) is incorporated concentrically around the valve (2).

The displacement sensor (12) includes an insulating bobbin (14) having a sensor coil (13) composed of a primary coil and a secondary coil wound on the outer peripheral surface, and an inner diameter of the bobbin (14). The bobbin (14) consists of a non-magnetic cylindrical core (15) with a slightly smaller diameter, and the bobbin (14)
By press-fitting the outer peripheral surface of the upper end of (4), the valve (2)
And are concentrically fixed. The core (15) is attached to the lower surface of the spring retainer (6) by a bobbin by a fixing means described later.
It is held concentrically with (14), and its lower end is located at the upper end in the bobbin (14) when the engine valve (2) is not operated (when the valve is closed).

When the spring retainer (6) moves up and down integrally with the opening and closing movement of the valve (2), the core (15) is placed in the bobbin (14) as shown by the imaginary line in FIG. A slight gap is formed between the inner surface and the inner surface. Multi-core lead wire (13a) connected to coil (13)
Is led out of the valve spring (8) through a wiring groove (16) formed on the upper surface of the cylinder head (3), and its end is connected to a measuring instrument body (not shown).

The sensor coil (1) in the displacement sensor (12)
When the primary coil of (3) is excited by high frequency, a large output voltage is obtained due to an eddy current effect when the non-magnetic core (15) moves in the bobbin (14) of the sensor coil (13), and the spring retainer ( 6), that is, a valve integral with this
The displacement of (2) can be measured with high accuracy.

As shown in FIG. 1, the air in the core (15) and the lubricating oil flowing into the bobbin (14) are applied to the bobbin (14) and the cylinder head (3). A discharge path (17) for discharging to the outside is provided.

The discharge path (17) has a plurality of vertically oriented through holes (18) formed in the sheet portion (14a) of the bobbin (14) so as to open into the bobbin (14). An annular groove (19) formed on the upper surface of the cylinder head (3) so as to be concentric with the shaft portion (2a) of the valve (2) and opposed to the lower end of the through hole (18); Annular groove (19) and cylinder head
A plurality of radially oriented discharge grooves opening to the outer peripheral surface of (3)
(20).

As shown in FIG.
(15) is fixed to the spring retainer (6) as follows.

That is, the upper surface of the outward flange portion (15a) formed integrally with the upper end of the core (15) and the inner peripheral surface of the upper end portion which is perpendicular to the upper surface are formed by the spring retainer (6). A lower surface inward of the receiving portion,
The upper end of the core (15) is made to be in close contact with the outer peripheral surface of the cylindrical portion (6a) and the entire contact surface thereof is coated with, for example, an epoxy resin adhesive (21). It is integrally fixed to the lower surface of (6).

With such a configuration, the two surfaces of the horizontal flange portion (15a) of the core (15) and the upper end portion vertically connected to the core (15) are bonded to the spring retainer (6), so that the fixing strength is reduced. Large, against vibration during engine operation, etc.
There is no risk of falling off. As a result, stable measurement can be performed over a long period of time, and durability can be improved.

FIG. 3 shows an embodiment of the second aspect of the present invention. After the core (15) is fixed by the adhesive (21), a plurality of screws (22) are further attached to the spring retainer (6). Screwed to the lower surface. In this case, the fixing strength of the core (15) is further increased.

FIG. 4 shows an embodiment of the invention according to claim 3, wherein the upper end of the core (15) is provided with a spring retainer.
It is press-fitted over the required length to the outer peripheral portion of the cylindrical portion (6a) in (6).

As described above, when the upper end of the core (15) is press-fitted relatively long, the pull-out resistance increases, and the core (15) can be firmly fixed to the spring retainer (6).

FIG. 5 shows an embodiment of the invention according to claim 4, wherein the core (15) is connected to the cylindrical portion of the spring retainer (6).
After being press-fitted into the (6a), the contact portion of the lower surface of the spring retainer (6) with the upper end of the core (15) is plastically deformed in the diameter reducing direction and caulked. Is firmly held.

In this way, the core (15) can be firmly fixed to the spring retainer (6), as compared with the press-fitting only fixing shown in FIG.

FIG. 6 shows an embodiment of the invention according to claim 5, wherein an annular concave groove (24) is formed on the outer peripheral surface of the cylindrical portion (6a) of the spring retainer (6), and the core (15) is formed. ) At the top
After press-fitting into (6a), the outer peripheral surface of the core (15) at the portion facing the annular groove (24) is plastically deformed toward the inside of the annular groove (24) and caulked, and the caulked portion (25) This prevents the core (15) from falling off. Also according to this embodiment, the fixing strength of the core (15) is high.

FIG. 7 shows an embodiment of the invention according to claim 6, wherein the core (15) and the spring retainer (6) are formed integrally. In this example, the material of the spring retainer (6) including the core (15) is preferably formed of a non-magnetic material such as brass, aluminum, or SUS304 in order not to lower the output sensitivity of the displacement sensor.

According to this embodiment, since the core (15) and the spring retainer (6) are completely integrated, there is no possibility that they are separated from each other.

FIG. 8 shows an embodiment of the invention according to claim 7, in which an outward flange portion (15a) connected to the upper end of a core (15) is connected to a spring receiving flange portion of a spring retainer (6). The upper surface of the valve spring (8) is pressed against the lower surface of the flange (15a) so that the core (15) is brought into close contact with the entire lower surface of the valve spring (6b).
It is fixed and held by the elastic force of (8).

A pin insertion hole (26) communicating with the spring receiving flange (6b) of the spring retainer (6), the flange (15a) of the core (15), and the upper end surface of the valve spring (8). (27) and (28) are formed and these insertion holes (2
Pins (2) from above the spring retainer (6)
9) may be press-fitted. In this way, relative rotation between the spring retainer (6) and the core (15) and between the core (15) and the valve spring (8) is prevented, so that there is no danger of their mutual contact surfaces being worn.

Further, the upper end of the core (15) may be press-fitted into the outer peripheral surface of the cylindrical portion (6a) of the spring retainer (6), so that the fixed holding of the core (15) becomes more reliable. Becomes

FIG. 9 shows an embodiment of the invention according to claim 8, wherein a threaded portion is formed on the inner surface of the upper end of the core (15).
(30) is screwed into a male thread portion (31) formed on the outer peripheral surface of the cylindrical portion (6a) of the spring retainer (6), thereby forming the core (15).
Is fixed to the spring retainer (6).

FIG. 10 shows an embodiment of the present invention.

In this embodiment, as shown in FIG.
A plurality of mounting pieces (32) facing upward are connected to the upper end of the core (15) made of a non-magnetic material, and the mounting pieces (32) of the core (15) can be inserted through the spring retainer (6). Through hole (33)
And an outward locking concave groove (34) connected to the upper end thereof, and the mounting piece (32) is inserted into each through hole (33) from below the spring retainer (6). The protruding end of the piece (32) is bent outward and recessed into the locking groove (34), thereby preventing the core (5) from dropping and rotating to the spring retainer (6). It is fixed.

In this embodiment, after the core (15) is attached, an adhesive may be poured into each of the through holes (33) and the locking grooves (34). The rattle is prevented and can be fixed firmly. The number of the locking pieces (32) is preferably, for example, 2 to 4, but may be more.

[0048]

According to the first aspect of the present invention, even if the core and the spring retainer are made of different materials, the core can be securely fixed with a sufficient joining strength and fall off due to vibration during operation. For example, there is no danger of impairing durability.

As in the second aspect of the present invention, when a screw is used in combination, the fixing strength of the core is further increased.

According to the third aspect of the present invention, since the press-fitting margin is large, the core can be firmly fixed to the spring retainer.

According to the fourth and fifth aspects of the present invention, the core can be firmly fixed to the spring retainer by the combined effect of press-fitting and caulking.

According to the sixth aspect of the present invention, the core and the spring retainer are completely integrated, so that there is no danger that they will be separated from each other.

According to the seventh aspect of the present invention, the core can be easily fixed and held by utilizing the elastic force of the valve spring.

According to the eighth aspect of the present invention, the core can be easily fixed to the spring retainer, and the core can be easily attached and detached, so that the maintenance of the valve operating mechanism can be easily performed.

According to the ninth aspect of the present invention, the core can be easily mechanically fixed without using a separate fixing means.

[0056]

[Brief description of the drawings]

FIG. 1 is a front view in central section of an entire valve train to which an embodiment of the present invention is applied.

FIG. 2 is an enlarged view showing a fixing portion of a core in FIG. 1;

FIG. 3 is an enlarged view showing a main part of the invention according to claim 2;

FIG. 4 is an enlarged view showing a main part of the invention according to claim 3;

FIG. 5 is an enlarged view showing a main part of the invention according to claim 4;

FIG. 6 is an enlarged view showing a main part of the invention according to claim 5;

FIG. 7 is an enlarged view showing a main part of the invention according to claim 6;

FIG. 8 is an enlarged view showing a main part of the invention according to claim 7;

FIG. 9 is an enlarged view showing a main part of the invention according to claim 8;

FIG. 10 is an enlarged view showing a main part of the invention according to claim 9;

11 is a perspective view of the core shown in FIG. 10;

[Explanation of symbols]

 (1) Valve mechanism (2) Engine valve (2a) Shaft (3) Cylinder head (4) Valve guide (6) Spring retainer (8) Valve spring (12) Displacement sensor (13) Sensor coil (13a) Core lead wire (14) Bobbin (15) Core (15a) Outward flange (21) Adhesive (22) Screw (23) (25) Crimp (24) Annular groove (26) (27) (28) Pin insertion hole (29) Pin (30) Female thread (31) Male thread (32) Mounting piece (33) Through hole (34) Locking groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Haruki Kobayashi F-term (reference) 2F063 AA02 BA06 BC02 BD15 CA29 DA01 DA05 DB04 DD02 GA15 GA30 GA33 PA01 at 1-22-1, Enry 行, Fujisawa-shi, Kanagawa Prefecture ZA01 2G024 AA15 BA11 CA04 2G087 AA11 CC02 CC40

Claims (9)

[Claims] 1. A sensor coil comprising a primary coil and a secondary coil wound around a cylinder head or an immovable member integral therewith and concentrically fixed to an engine valve. Measurement of the displacement of an engine valve, which can be moved up and down in the bobbin and detected by a differential transformer type displacement sensor consisting of a cylindrical core whose upper end is attached to a spring retainer. In the device, an outward flange portion is provided at an upper end portion of the core, and the flange portion and the inner surface of the upper end portion of the core are respectively connected to a lower surface inward of a valve spring receiving portion of the spring retainer and a cylinder connected thereto. A displacement measuring device for an engine valve, wherein the displacement measuring device is fixed to an outer peripheral surface of a portion with an adhesive. 2. The engine valve displacement measuring device according to claim 1, wherein the outward flange portion of the core is fixed to the spring retainer with an adhesive and a plurality of screws. 3. A sensor coil composed of a primary coil and a secondary coil is wound around a cylinder head or an immovable member integral therewith, concentrically with the engine valve. Measurement of the displacement of an engine valve, which can be moved up and down in the bobbin and detected by a differential transformer type displacement sensor consisting of a cylindrical core whose upper end is attached to a spring retainer. An apparatus for measuring displacement of an engine valve, wherein an upper end portion of the core is press-fitted into an outer peripheral surface of a cylindrical portion of a spring retainer over a required length. 4. The displacement measurement of an engine valve according to claim 3, wherein an upper end of the core is caulked by plastically deforming a portion of the lower surface of the spring retainer that contacts the upper end of the core in a radially-reducing direction. apparatus. 5. A groove is formed in an outer peripheral surface of a cylindrical portion of a spring retainer, and an outer peripheral surface of a core at a portion facing the concave groove is caulked by being plastically deformed into the concave groove. Item 3. An apparatus for measuring displacement of an engine valve according to item 3. 6. A sensor coil comprising a primary coil and a secondary coil wound around a cylinder head or an immovable member integrally formed with the cylinder head and concentrically with the engine valve. Measurement of the displacement of an engine valve, which can be moved up and down in the bobbin and detected by a differential transformer type displacement sensor consisting of a cylindrical core whose upper end is attached to a spring retainer. An apparatus for measuring displacement of an engine valve, wherein the core is formed integrally with a spring retainer formed of a nonmagnetic material. 7. A sensor coil comprising a primary coil and a secondary coil wound around a cylinder head or an immovable member integral therewith and concentrically fixed to the cylinder valve or an immovable member integral with the cylinder valve. Measurement of the displacement of an engine valve, which can be moved up and down in the bobbin and detected by a differential transformer type displacement sensor consisting of a cylindrical core whose upper end is attached to a spring retainer. In the device, a large-diameter outward flange portion is provided at an upper end portion of the core,
An engine valve displacement measuring device, characterized in that the outward flange portion is clamped and fixed between the lower surface of a spring retainer and the upper end of a valve spring. 8. A displacement of the engine valve is concentrically fixed to the cylinder head or a stationary member integral therewith with the engine valve, and a sensor coil comprising a primary coil and a secondary coil is wound around the outer peripheral surface. Measurement of the displacement of an engine valve which is detected by a differential transformer type displacement sensor comprising a bobbin and a cylindrical core mounted on a spring retainer so that the bobbin can move up and down in the bobbin. In the device, the core may be integrally fixed to the spring retainer by screwing a threaded portion for forming the core on the inner surface of the upper end portion with a male threaded portion formed on the outer peripheral surface of the cylindrical portion of the spring retainer. Characteristic engine valve displacement measurement device. 9. A sensor coil comprising a primary coil and a secondary coil wound around a cylinder head or an immovable member integrally formed with the cylinder head and concentrically with the engine valve, and the outer peripheral surface thereof is wound. Measurement of the displacement of an engine valve, which can be moved up and down in the bobbin and detected by a differential transformer type displacement sensor consisting of a cylindrical core whose upper end is attached to a spring retainer. In the device, a plurality of upwardly-facing mounting pieces are protruded from an upper end of the core, and the mounting pieces are inserted from below into insertion holes formed in a spring retainer, and the protruding end portions are bent outward. The displacement measuring device for an engine valve, wherein the core is fixed to the spring retainer.