JPH11329761A - Discharge lamp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of performance when a ballast case in a discharge lamp device is thinned. SOLUTION: In this discharge lamp device, a cross-sectional area S (mm<2> ) of a core 1a of a starter transformer 1 received in a ballast case 10 and an inside height H (mm) on the ballast case 10 satisfy a relationship of H<=-0.0015.S<2> +0.54.S-11.49 and a closed magnetic circuit core 1a is used as the core. In addition, a gap 1c of the closed magnetic circuit core 1a is formed on the center side of the ballast case 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp device for lighting a high-pressure discharge lamp, and is particularly suitable for use as a headlight of a vehicle.

[0002]

2. Description of the Related Art Hitherto, various proposals have been made in which a high-pressure discharge lamp (hereinafter, referred to as a lamp) is applied to a vehicle headlamp and a lamp is turned on by a ballast (lamp lighting circuit). Here, at the start of lighting of the lamp, a voltage of about 20 kV is obtained by using a starter transformer, a capacity discharge is generated between the electrodes of the lamp by the voltage of about 20 kV, an arc is formed, and then the operation is shifted to stable lighting. I have to.

[0003] The ballast case described above is disposed outside the housing of the headlight. That is, as shown in FIG. 7, the ballast case 10 is
And is electrically connected to the lamp 13 from the ballast case 10 via the wiring 12. In addition, 14 is a reflector.

[0004]

As described above, when the ballast case 10 is mounted outside the housing 11 of the headlight, a space for mounting the ballast case 10 must be secured outside the housing 11. Therefore, as shown in FIG. 8, the ballast case 10 is connected to the housing 11 of the headlight.
It is possible to arrange in. In this case, it is necessary to reduce the thickness of the ballast case 10 in order to fit the narrow space in the housing 11.

However, when the ballast case 10 is made thinner, a problem arises in that the performance of the starter transformer housed in the ballast case 10 is reduced. That is, an open magnetic circuit type is used as the starter transformer, and the ballast case 10 is made of a conductor such as aluminum for shielding electromagnetic waves. The magnetic flux increases and the performance is greatly reduced. Hereinafter, this point will be described.

FIG. 9A shows a state in which the starter transformer 1 is housed in a ballast case 10. FIG.
FIG. 9B shows a cross-sectional state taken along line DD in FIG. The starter transformer 1 is of an open magnetic circuit type in which a coil 1b is wound around a core 1a, and a current flows through the coil 1b in a direction indicated by a solid arrow in FIG. 9A. At this time, a magnetic flux is formed in the direction of the arrow shown in FIG. If the effective magnetic flux of the winding portion is φ1, the magnetic flux in the ballast case 10 is φ2, and the magnetic flux leaking out of the ballast case 10 is φ3, φ1 = φ2 + φ3.

At this time, the total magnetic flux in the ballast case 10 is φ1−φ2 (= φ3), and the ballast case 10 which is a conductor has a direction of canceling φ1−φ2 (FIG. 9).
An eddy current flows in the direction indicated by the dotted arrow in (a)).
Therefore, the effective magnetic flux for the starter transformer 1 is approximately (φ1
−φ3), and the performance is reduced according to the amount of magnetic flux leaking out of the ballast case 10. In this case, countermeasures such as addition of a primary booster circuit and an increase in the capacity of a charging capacitor must be taken, and the cost for securing performance is greatly increased.

In order to solve such a problem, if a starter transformer 1 of a closed magnetic circuit type is used, the ratio of the magnetic flux φ3 can be reduced, and a decrease in performance can be prevented. However, even in the case of the closed magnetic circuit type, since a gap is provided in the closed magnetic circuit core in order to prevent magnetic saturation, performance may be deteriorated due to leakage magnetic flux due to the gap.

The present invention has been made in view of the above problems, and a first object of the present invention is to prevent a decrease in performance without increasing the cost when a ballast case is thinned. A second object of the present invention is to prevent performance degradation when the starter transformer is of a closed magnetic circuit type.

[0010]

Means for Solving the Problems The present inventor evaluated leakage magnetic flux in the gap portion of the closed magnetic circuit core in the above-mentioned closed magnetic circuit type. As a method of calculating the magnetic path of the gap, Roter restricts to a simple geometrical figure.
There is a permeance formula for s. Therefore, the magnetic path in the gap portion is divided into five parts as shown in FIG. 10A is a perspective view, and FIG.
Indicates a cross-sectional state. Permeance P1 of each magnetic path
P5 (P1 is a semi-cylindrical portion, P2 is a semi-hollow cylindrical portion, P3
4 minutes sphere portion, P4 is 4 minutes spherical shell, P5 permeance) of the magnetic path in the opposite part, upon the permeability of air and mu _0, is expressed by Equation 1 Equation 5.

[0011]

## EQU1 ## P1 = 2 · 0.26 · μ ₀ · (a + b)

[0012]

[Number 2] _{P2 = 2 · μ 0 · (} a + b) / π · ln (1+
2. X / g)

[0013]

[Number 3] _{P3 = 4 · 0.077 · μ 0} · g

[0014]

## EQU4 ## P4 = μ ₀ · X

[0015]

The proportion of the magnetic flux passing through the Equation 5] _{P5 = μ 0 · a · b} / g each path, when the respective magnetic paths are connected in parallel, proportional to the ratio of the permeance. Here, when the ballast case 10 is reduced in thickness, the outermost shells P2 and P4 pass through the outside of the ballast case 10, and the performance degradation can be estimated by the magnetic flux ratio.
In this case, the estimation of the performance drop depends on how to take X, but X is set to a maximum value of 20 mm, which is affected as leakage magnetic flux. Also, the size of the gap g
Increases, the magnetic fluxes in the P1 and P3 portions also become leakage magnetic fluxes, and the performance degradation further increases. If g≫a, b, then
The performance reduction ratio is almost saturated, and the performance reduction in the open magnetic circuit can be estimated.

In this manner, the magnetic flux leakage in the gap portion is evaluated, and the cross-sectional area S (mm ² ) of the core is evaluated for performance degradation.
The relationship between the height of the ballast case 10 and the inner height H (mm) was examined. FIG. 11 shows the core cross-sectional area S and the height H inside the ballast case. When the core cross-sectional area S is constant, the performance decreases as the ballast case inner height H decreases. Conversely, when the ballast case inner height H is constant, the performance decreases as the core cross-sectional area S increases. .

FIG. 12 shows a boundary line between the core cross-sectional area S and the ballast case inner height H when the performance is reduced by 10% due to the leakage magnetic flux when g is sufficiently large, that is, when the magnetic flux becomes substantially an open magnetic circuit. Show. This boundary line is H = −0.
0015 · S ² + 0.54 · S-11.49 The lower part of the boundary line shows that the performance is greatly reduced in the open magnetic circuit type, and it is difficult to secure the performance in the non-closed magnetic circuit type. Therefore, as described in claim 1, H ≦ −0.0015 · S ² + 0.54 · S−
If the relationship of 11.49 is satisfied, it is possible to prevent the performance from decreasing without increasing the cost as a closed magnetic circuit type.

Further, when the starter transformer is constituted by a closed magnetic circuit type, the starter transformer 1 becomes a high voltage section for generating a voltage of about 20 kV, and therefore cannot be arranged at the center even in the ballast case 10. For this reason, the starter transformer 1 is disposed at the end in the ballast case 10. In this case, if the leakage magnetic flux in the gap portion interlinks with the side wall in the ballast case 10,
Performance decreases.

In view of the above, according to the second aspect of the present invention, the starter transformer 1 is disposed so as to be biased toward one side of the opposing side walls in the ballast case 10 and is located at the other side of the both sides of the closed magnetic circuit core. It is characterized in that a gap of a closed magnetic circuit core is provided. In this case, on the other side of the both side walls, since it is separated from the side wall in the ballast case 10, it is possible to reduce leakage flux in the gap portion from linking with the side wall in the ballast case 10 and to prevent performance degradation. Can be.

In the invention according to claim 3,
The ballast case 10 is characterized in that the starter transformer 1 is biased to one side in the longitudinal direction, and a gap of the closed magnetic path core is provided at a position on the other longitudinal side of the closed magnetic path core. Also in this case, the gap of the closed magnetic path core can be placed at a position away from the side wall in the ballast case 10, so that the performance can be prevented from deteriorating.

Further, in the invention according to claim 4,
When the sectional area of the closed magnetic circuit core is S (mm ² ) and the size of the gap of the closed magnetic circuit core is g (mm), the clearance L between the inner wall of the ballast case and the gap of the closed magnetic circuit core is set.
(Mm) satisfies the relationship of L ≧ 28.2 · e ^{−0.075 (S / g)} . By setting the clearance L to the above-mentioned relationship, it is possible to reduce the possibility that the leakage magnetic flux in the gap portion interlinks with the side wall in the ballast case 10 and prevent the performance from being lowered.

[0022]

FIG. 1 shows a partial cross-sectional configuration of a ballast in a discharge lamp device according to an embodiment of the present invention.
(A) shows an AA cross section of (b), and (b) shows a BB cross section of (a). In this embodiment, a ballast case 10 made of aluminum is arranged in a headlight housing 11 as shown in FIG.
Various electric components for lighting the lamp 13 are housed in the ballast case 10, and FIG. 1 shows only a part of the starter transformer 1 in a cross-sectional state.

The starter transformer 1 includes a closed magnetic circuit core 1a and a coil 1b.
A gap 1c is provided. In the present embodiment, a closed magnetic path core 1a having a sectional area S of about 120 mm ² is used, and the inner height H of the ballast case 10 is about 17 mm.
mm. In this case, the core cross-sectional area S
And the ballast case inner height H is H ≦ −0.0015.
Since the relationship of S ² + 0.54 · S-11.49 is satisfied, sufficient performance cannot be obtained unless the starter transformer 1 is a closed magnetic circuit type.

Further, since the starter transformer 1 is a high-pressure section, the end in the ballast case 10, one side in the longitudinal direction of the rectangular ballast case 10 (in other words, opposing side walls 10 a in the ballast case 10, 1
0b (one side wall 10a side). Here, a gap 1c is provided at the center of the closed magnetic circuit core 1a, that is, at the position on the other side in the longitudinal direction in the ballast case 10 (in other words, on the other side wall 10b side). As a result, it is possible to prevent the leakage magnetic flux of the gap 1c from interlinking with the ballast case 10, and to prevent performance degradation.

That is, when the starter transformer 1 is arranged at the end of the ballast case 10, the gap 1c of the closed magnetic circuit core 1a is provided at the end of the ballast case 10 as shown in FIGS. However, in this case, the leakage flux of the gap 1c is
Therefore, the performance is reduced. On the other hand, as shown in FIG. 1, when the gap 1c of the closed magnetic circuit core 1a is provided on the center side in the ballast case 10, the gap 1c is provided at a position away from the side walls 10a and 10b. The leakage magnetic flux of 1c is less likely to interlink with the ballast case 10, so that performance degradation can be prevented.

As shown in FIG. 4, the gap 1c of the closed magnetic circuit core 1a may be provided at two places on the center side in the ballast case 10. Also, the other side in the longitudinal direction in the ballast case 10, that is, the side wall 10b
If a gap 1c is provided on the side of the ballast case 10, the leakage magnetic flux can be reduced by utilizing the wide space in the ballast case 10.
However, the starter transformer 1 is connected to the opposing side walls 10 in the ballast case 10.
When they are arranged at a position deviated toward one of the side walls of c and 10d, they may be provided on the other side wall.

In some cases, the gap 1c must be provided at the end of the ballast case 10, that is, at the side wall 10b, as shown in FIG. In this case as well, performance degradation can be prevented by performing the following studies. When there is a gap on the wall side of the ballast case 10 as shown in FIG. 2, in FIG. 5 showing a cross section taken along the line CC of FIG.
The performance decrease in the P4 region is large. And Equations 1
By calculating various core cross-sectional areas S and gap sizes g using Expression 5, and calculating the performance degradation, FIG.
become that way.

In FIG. 6, the horizontal axis is S (mm ² ) / g (m
m), the vertical axis is the gap 1 with the inner wall of the ballast case 10.
The clearance L (mm) between the gap c and the required clearance L is dominant to S / g, which means that the magnetic resistance of the gap 1c (= S / μg: P5 region not considering the leakage magnetic flux) Increases, the ratio of the leakage magnetic flux increases, and as a result, a clearance with the ballast case 10 is required.

As can be seen from FIG. 6, L ≧
If the relationship of 28.2 · e ^{−0.075 (S / g)} is satisfied, the performance degradation can be suppressed to 10% or less.

[Brief description of the drawings]

FIG. 1 is a diagram showing a partial cross-sectional configuration of a ballast in a discharge lamp device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example in which a gap 1c of a closed magnetic circuit core 1a is provided at an end in a ballast case 10.

FIG. 3 is a view showing another example in which a gap 1c of a closed magnetic circuit core 1a is provided at an end in a ballast case 10;

FIG. 4 is a view showing another example in which a gap 1c of a closed magnetic circuit core 1a is provided on the center side in a ballast case 10.

FIG. 5 is a diagram showing a cross-sectional state taken along the line CC in FIG. 2;

FIG. 6 is a diagram showing the relationship between the clearance L and the core cross-sectional area S / gap size g.

FIG. 7 is a view showing a mounting position of a conventional ballast case 10.

FIG. 8 shows a ballast case 1 according to an embodiment of the present invention.
It is a figure which shows the attachment position of 0.

FIG. 9 is a view showing a state in which a starter transformer 1 is housed in a ballast case 10 in a conventional one.

FIG. 10 is an explanatory diagram in the case of evaluating leakage magnetic flux in a gap portion of a closed magnetic circuit core.

FIG. 11 is an explanatory diagram for explaining a core cross-sectional area S and a ballast case inner height H;

FIG. 12 is a diagram illustrating a relationship between a core sectional area S and a ballast case inner height H;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Starter transformer, 1a ... Closed magnetic circuit core, 1b ... Coil, 1c ... Gap, 10 ... Ballast case, 11 ... Headlight housing, 12 ... Wiring, 13 ... Lamp, 14 ...
Reflector.

Continuing on the front page (72) Inventor Yasushi Noyori 500 Kitawaki, Shimizu-shi, Shizuoka Prefecture Inside the Shizuoka Plant of Koito Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A discharge lamp device comprising a starter transformer housed in a ballast case, wherein a closed magnetic circuit core is used as a core of the starter transformer.
The height H (mm) inside the ballast case and the cross-sectional area S (mm ² ) of the closed magnetic circuit core satisfy the relationship of H ≦ −0.0015 · S ² + 0.54 · S-11.49. A discharge lamp device. 2. A discharge lamp device in which a starter transformer is housed in a ballast case, wherein a closed magnetic circuit core is used as a core of the starter transformer, and the starter is biased to one side of opposing side walls in the ballast case. A discharge lamp device, wherein a transformer is arranged, and a gap of the closed magnetic path core is provided at a position on the other side of the both side walls in the closed magnetic path core. 3. A discharge lamp device in which a starter transformer is housed in a rectangular parallelepiped ballast case, wherein a closed magnetic circuit core is used as a core of the starter transformer, and one end of the ballast case in the ballast case in a longitudinal direction. The discharge lamp device, wherein the starter transformer is biased and a gap of the closed magnetic path core is provided at a position on the other side in the longitudinal direction of the closed magnetic path core. 4. A discharge lamp device in which a starter transformer is housed in a ballast case, wherein a closed magnetic circuit core is used as a core of the starter transformer, and a cross-sectional area of the closed magnetic circuit core is S (mm ² ). When the size of the gap of the core is g (mm), the clearance L (mm) between the inner wall of the ballast case and the gap of the closed magnetic circuit core is L ≧ 28.2 · e.
A discharge lamp device satisfying a relationship of ^{-0.075 (S / g)} .