JP2000136902A - Displacement measuring apparatus for engine valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a displacement measuring apparatus which prevents a measuring error by providing the apparatus with a discharge passage by which lubricating oil flowing into a bobbin or the air inside a core and the bobbin is discharged outside the bobbin at the lower end part of the bobbin. SOLUTION: When the primary coil of a sensor coil 13 in a displacement sensor 12 is excited by a high frequency, a large output voltage is obtained by an eddy-current effect at a time when a nonmagnetic core 15 is moved inside a bobbin 14. Thereby, the displacement of a spring retainer 6, i.e., a valve 2 which is integrated with it, can be measured with high precision. A discharge passage 17 by which the air inside the core 15 and lubricating oil flowing into the bobbin 14 are discharged outside is formed in the bobbin 14 and a cylindrical head 3. As a result, the lubricating oil flowing into the bobbin 14 flows down into a ring-shaped recessed groove 19 from plurality of through holes 18, and it flows outside the bobbin 14 via a discharge groove 20. Also the air which is confined inside the bobbin 14 and the core 15 flows out when the spring retainer 6 falls.

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 carried out by detecting the axial displacement of a valve or a valve operating part (spring retainer or the like) moving integrally therewith by a proximity sensor or the like. For direct-acting valve trains where the shaft end or spring retainer is covered by a cap-shaped tappet, or for small engines with little space around the valve train, attach a proximity sensor, etc. It may be difficult to directly detect the displacement of the spring retainer.

[0004] Therefore, in the above-mentioned direct acting valve operating mechanism,
Remove the piston and connecting rod from the cylinder block, provide a proximity sensor, etc., directly below the valve in the cylinder, and operate the engine on a table (motoring) to measure the axial displacement of the valve from the front of the umbrella. ing.

[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. However, it has been found that the following problem may occur. .

That is, the lubricating oil scattered due to the movement of the valve train component may flow into and accumulate in the bobbin, hindering the movement of the core, or causing a change in magnetic characteristics to cause a measurement error.

In addition, since the gap between the inner peripheral surface of the bobbin and the outer peripheral surface of the core is small, the air trapped in the core and the bobbin is not quickly discharged to the outside, but is very small. This may adversely affect the vertical movement of the valve.

[0010] The present invention has been made in view of the above problems, and prevents a measurement error from occurring by quickly discharging the lubricating oil flowing into the bobbin and the air trapped in the core to the outside. Another object of the present invention is to provide an engine valve displacement measuring device which does not hinder the movement of the engine valve.

[0011]

According to the present invention, the above-mentioned problem is solved as follows. (1) The displacement of the engine valve is controlled by a bobbin which is fixed concentrically to the engine valve to the cylinder head or an immovable member integrally formed with the cylinder head, and has a primary and secondary coil wound on the outer peripheral surface thereof. An engine which is capable of moving up and down in a bobbin, and is detected by a differential transformer type displacement sensor having an upper end portion fixed to an engine valve or a member which moves following the engine valve. In the valve displacement measuring device, at the lower end of the bobbin,
A discharge path is provided for discharging the lubricating oil or core flowing into the bobbin and the air in the bobbin to the outside of the bobbin.

(2) In the above item (1), the discharge path is communicated with a plurality of vertically oriented through holes formed in the sheet portion at the lower end of the bobbin and the lower ends of the openings of the respective through holes. , An annular groove formed on the upper surface of the cylinder head, and a plurality of discharge grooves opened to the outer peripheral end of the cylinder head so as to communicate with the annular groove.

(3) In the above item (1), the discharge path is a plurality of obliquely downwardly extending through holes formed in the sheet portion of the bobbin in the radial direction so as to communicate with the inside and outside of the bobbin.

(4) In the above item (1), the discharge passage is formed so as to communicate with the annular groove formed on the upper surface of the bobbin sheet portion and the seat portion with the annular groove and the outside of the bobbin. And a plurality of through-holes extending in the radiation direction.

[0015]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 shows a main part of a direct acting valve train (1) to which the inventions of claims 1 and 2 are applied.

The shaft (2a) of the valve (2) is a cylinder head.
The valve guide (4) is press-fitted into (3) and is slidably guided in the vertical direction. At the upper end of the shaft (2a), a half-cotter-shaped cotter (5) (5) is used. The spring retainer
(6) is attached. A coil-shaped valve spring (8) is contracted between the spring retainer (6) and a washer (7) placed on the upper surface of the cylinder head (3).

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 on 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
An annular space (A) formed between (4) and the valve spring (8) has a differential transformer type displacement sensor (12).
Are installed concentrically so as to surround the valve (2).

The displacement sensor (12) includes a bobbin (1) having a sensor coil (13) composed of a primary coil and a secondary coil wound on the outer peripheral surface.
4) and a cylindrical core (15) having an outer diameter slightly smaller than the inner diameter of the bobbin (14). The bobbin (14) has a thick seat portion (14a) at the lower end and a valve guide (4). ) Is fixed concentrically with the valve (2) by press-fitting the outer peripheral surface of the upper end. The core (15) has a spring retainer (6) at its upper end.
By press-fitting and fixing to the lower surface of the bobbin (14), it is held concentrically with the bobbin (14), and its lower end is
When (2) is not operated (when the valve is closed), it is located at the upper end in the bobbin (14).

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. The multi-core lead wire (15) connected to the coil (13)
It 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 a high frequency, a large output voltage is obtained by an eddy current effect when the non-magnetic core (15) moves in the bobbin (14) of the sensor coil (13). (6), that is, a valve integrated with this
The displacement of (2) can be measured with high accuracy.

As shown in FIGS. 1 and 2, the bobbin (14) and the cylinder head (3) are filled with air in the core (15) and lubricating oil flowing into the bobbin (14). A discharge path (17) for discharging to the outside of 14) is provided.

The discharge path (17) includes 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
(3) A plurality of radially oriented discharge grooves opening to the outer peripheral end
(20).

The lubricating oil that has flowed into the bobbin (14) flows down through the plurality of through holes (18) into the annular groove (19), and flows out of the bobbin (14) through the discharge groove (20). Bobbin (14) and core
(15) The air trapped inside
When (6) descends, the bobbin (14) passes through the discharge path (17).
Spill out of the

FIGS. 3 and 4 show a modification of the discharge path, that is, the invention according to claims 3 and 4. In the embodiment shown in FIG. 3, the bobbin (14) is simply provided on the sheet portion (14a). A plurality of obliquely downwardly extending through holes (21) are formed in the inside and the outer peripheral surface of the cylinder head (3).

In the embodiment shown in FIG. 5, the bobbin (1
An annular groove (22) is formed on the upper surface of the sheet portion (14a) in 4), and the annular groove (22) and the sheet portion (14a) are formed.
Multiple radially-directed through-holes (23) opening to the outer peripheral edge of the
Is formed.

In both of the above embodiments, the lubricating oil flowing into the bobbin (14) and the air trapped in the bobbin (14) and the core (15) are supplied to the through holes (21) (23) and the annular It flows out of the bobbin (14) from the groove (22).

Although not shown, a wiring groove similar to the wiring groove (16) of the lead wire (15) is separately formed in addition to the above-described embodiments, and a discharge path communicating with the wiring groove is formed on a bobbin. It may be provided on the sheet portion (14a) of (14).

[0030]

According to the first aspect of the invention, the lubricating oil flowing into the bobbin and the air confined in the bobbin and the core are discharged to the outside of the bobbin from the discharge path.
There is no hindrance to the vertical movement of the engine valve, and no measurement error by the sensor occurs.

According to the second aspect of the present invention, the lubricating oil that has flowed into the bobbin quickly flows out of the plurality of through holes into the annular groove, and is discharged to the outside through the discharge groove. The lubricating oil does not stay for a long time, and the measurement error due to the lubricating oil is almost eliminated.

According to the third aspect of the present invention, since the through-hole is inclined obliquely downward and its length is short, the lubricating oil and the air can be quickly discharged.

According to the fourth aspect of the present invention, the lubricating oil does not stay in the bobbin for a long time as in the second aspect of the present invention, thereby preventing measurement errors from occurring.

[0034]

[Brief description of the drawings]

FIG. 1 is a central longitudinal sectional front view showing a direct-acting type valve train to which the inventions of claims 1 and 2 are applied.

FIG. 2 is a cross-sectional plan view of an essential part taken along line II-II of FIG.

FIG. 3 is a semi-longitudinal front view of a main part of the invention according to claim 3;

FIG. 4 is a semi-longitudinal front view of a main part of the invention according to claim 4;

[Explanation of symbols]

 (1) Valve mechanism (2) Engine valve (2a) Shaft (3) Cylinder head (4) Valve guide (5) Cotta (6) Spring retainer (7) Washer (8) Valve spring (9) Lip seal ( 10) Tappet (11) Shim (12) Displacement sensor (13) Sensor coil (14) Bobbin (14a) Seat (15) Multi-core lead wire (16) Wiring groove (17) Discharge path (18) Through hole (19 ) Circular groove (20) Discharge groove (21) Through hole (22) Circular groove (23) Through hole

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Haruki Kobayashi 1-22-1, Fujisawa-shi, Kanagawa Fuji Ozex Co., Ltd. F-term (reference) 2F063 AA35 BA06 BB05 BC03 BD16 CA09 CA12 DA01 DA04 DB03 DC08 DD02 GA15 PA05 2F077 AA25 AA33 FF25 FF26 UU15

Claims (4)

[Claims] 1. A bobbin having a cylinder head or a stationary member integral therewith concentrically fixed to an engine valve and having a primary and secondary coil wound on an outer peripheral surface thereof. The bobbin can be moved up and down, and the upper end is detected by a differential transformer type displacement sensor comprising a cylindrical core fixed to an engine valve or a member that moves following the valve. An engine valve displacement measuring device, wherein a discharge path for discharging lubricating oil or core flowing into the bobbin and air in the bobbin to the outside of the bobbin is provided at a lower end portion of the bobbin. Displacement measuring device. 2. A discharge passage is formed on the upper surface of the cylinder head so as to communicate with a plurality of vertically extending through holes formed in a sheet portion at the lower end of the bobbin and with the lower ends of the openings of the respective through holes. 2. The displacement measuring device for an engine valve according to claim 1, wherein the device comprises an annular groove formed and a plurality of exhaust grooves opened at an outer peripheral end of the cylinder head so as to communicate with the annular groove. 3. The displacement of the engine valve according to claim 1, wherein the discharge passage is formed by a plurality of obliquely downwardly extending through holes formed in the seat portion of the bobbin in a radial direction so as to communicate with the inside and outside of the bobbin. measuring device. 4. A discharge path is defined by an annular groove formed on the upper surface of the sheet portion of the bobbin, and a radial direction formed in the sheet portion so as to communicate with the annular groove and the outside of the bobbin. The engine valve displacement measuring device according to claim 1, comprising a plurality of facing through holes.