JP7811538B2 - lighting fixtures - Google Patents

Description

The present invention relates to a lighting fixture.

In lighting fixtures in which the fixture body is supported on the ceiling surface by an arm, numerous heat dissipation fins are provided on the top surface of the fixture body to dissipate heat from the light source installed inside the fixture body (see, for example, Patent Documents 1 to 5).

Japanese Patent Application Laid-Open No. 2019-29214 Japanese Patent Application Laid-Open No. 2018-77957 Japanese Patent Application Laid-Open No. 2018-195459 JP 2017-41328 A Japanese Patent Application Laid-Open No. 2017-208364

However, if dust accumulates on the heat dissipation fins, the heat dissipation performance will decrease, and if the ceiling is high, it is not easy to clean the heat dissipation fins on the top surface of the appliance body.
Furthermore, since the overall height of the fixture body is increased by the length of the heat dissipation fins, the strength of the arm needs to be increased to ensure vibration resistance, but strengthening the arm ends up increasing the weight of the lighting fixture.

The objective of the present invention is to provide a lighting fixture that can minimize a decrease in heat dissipation performance and an increase in weight.

the light source board is attached to the underside of the light source board mounting plate in a state where the entire surface of the light source board is in contact with the underside of the light source board mounting plate; a support part supporting the power supply part is formed in a box shape with one open side, and the support part is installed on the upper surface of the light source board mounting plate so that the open side faces toward the upper surface of the light source board mounting plate and the open side is closed by the upper surface of the light source board mounting plate; the power supply part is attached to the face of the support part facing the open side, and supports the power supply part so that the power supply part and the light source board mounting plate are separated in the vertical direction; the power supply part is floating above the upper surface of the light source board mounting plate to provide a gap; and the light source board mounting plate has no heat dissipation fins in the gap.

The present invention is characterized in that, in the above-mentioned lighting fixture, the light source board mounting plate is provided with arm connecting pieces formed by bending each of the edges on both sides of the mounting portion to which the light source board is attached upward into an L-shape so as to surround the power supply unit .

The present invention is characterized in that, in the above-mentioned lighting fixture , the arm connecting piece is formed in a mountain shape that becomes higher toward the center of the side of the light source board mounting plate, the maximum length of the arm connecting piece in the front-to-rear direction is shorter than the total length of the mounting part in the front-to-rear direction, and the arm is connected by making face contact with the center of the arm connecting piece, and each of the arm connecting pieces is provided with a plurality of through-hole portions that open facing the power supply unit.

The present invention is characterized in that, in the above-mentioned lighting fixture, the power supply device has a power supply board, and the power supply board is fixed to a surface of the support part facing the open surface inside the box-shaped support part so as to be spaced apart from the light source board mounting plate.

The present invention is characterized in that, in the above-mentioned lighting fixture, the power supply unit has an opening communicating with the interior at a position that does not face any of the arm connecting pieces.

This invention makes it possible to prevent a decrease in heat dissipation performance and an increase in weight.

1 is a perspective view of a lighting fixture according to an embodiment of the present invention, viewed obliquely from below. FIG. 2 is a perspective view of the lighting fixture as viewed obliquely from above. FIG. FIG. 4 is a cross-sectional view taken along line VV in FIG. 3. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. FIG. FIG. FIG. FIG. 10 is a diagram showing the configuration of a lighting fixture according to a first modified example of the present invention. 10A and 10B are diagrams showing the configuration of a lighting device according to a second modified example of the present invention, in which (A) shows a case in which a light source unit having a square shape when viewed from the bottom, and (B) shows a case in which a light source unit having a rectangular shape when viewed from the bottom. FIG. 10 is a diagram showing the configuration of a lighting fixture according to a third modified example of the present invention. FIG. 10 is a diagram showing the configuration of a lighting fixture according to a fourth modified example of the present invention. FIG. 10 is a diagram showing the configuration of a lighting fixture according to a fifth modified example of the present invention. FIG. 10 is a diagram showing the configuration of a lighting fixture according to a sixth modified example of the present invention. FIG. 10 is a diagram showing the configuration of a lighting fixture according to a sixth modified example of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 is a perspective view of a lighting fixture 1 according to this embodiment as viewed obliquely from below, Fig. 2 is a perspective view of the lighting fixture 1 as viewed obliquely from above, Fig. 3 is a top view of the lighting fixture 1, and Fig. 4 is an exploded view of the lighting fixture 1.
The lighting fixture 1 of this embodiment is a ceiling lighting fixture to be installed on the ceiling surface of a high ceiling, etc. As shown in these figures, the lighting fixture 1 includes a fixture body 4, an arm 6 fixed to the ceiling surface of a high ceiling, etc., for rotatably supporting the fixture body 4, and a power supply device 8 for supplying power to the fixture body 4.
In Fig. 1, the direction in which the ceiling surface is located when viewed from the installed lighting fixture 1 is the upward direction of the paper, and this direction is defined as the upward direction of the lighting fixture 1. The definitions of the directions of the lighting fixture 1, including up, down, left, and right, are also shown in Fig. 1.

The fixture body 4 has a light source board mounting plate 10 and a light source unit 12 .
2 to 4, the light source board mounting plate 10 integrally includes a mounting portion 11 having a generally rectangular plate shape in plan view and a pair of arm connecting pieces 14. A power supply unit 8 is installed in the center of an upper surface 11A of the mounting portion 11. A light source unit 12 is provided on a lower surface 11B of the mounting portion 11, as shown in FIG.

The arm connecting pieces 14 are provided on both sides of the mounting portion 11, and as shown in Figure 4, two press nuts 16 are provided on each arm connecting piece 14, one above the other, and the arm 6 is connected to each press nut 16 through a bolt 15. Note that press nuts are also called embedded nuts.
These arm connecting pieces 14 are integrally formed with the mounting portion 11 by bending the edges on both sides of the light source board mounting plate 10, sandwiching the mounting portion 11, upward into an L-shape. On the other hand, the front edge 11K1 of the mounting portion 11 and the rear edge 11K2 of the mounting portion 11 are not bent, and the portions between the front edge 11K1 and the rear edge 11K2 and the power supply device 8 are formed as flat surfaces without any irregularities.

The light source board mounting plate 10 is made of sheet metal with high thermal conductivity and the desired rigidity; in this embodiment, a 3 mm thick aluminum alloy is used.

5 is a cross-sectional view taken along line VV in FIG. 3, and FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.
As shown in Figure 6, the power supply unit 8 includes a power supply board 20 on which an electrical circuit for generating power to be supplied to the light source unit 12 is mounted, a terminal block 21 to which wiring for transmitting external power and lighting control signals is connected, and a metal power supply cover case 22 that houses these components.

The power supply cover case 22 is a bottomless box-like structure with the entire bottom surface open, and is fixed to the upper surface 11A of the mounting portion 11 with screws, with the bottom surface facing the light source board mounting plate 10 side.
The power supply board 20 is fixed with an insulating space provided on the top surface 22A of the power supply cover case 22. This top surface 22A is provided with a plurality of press nuts 25 (FIG. 6) that are convex on the bottom surface side, and by screwing the power supply board 20 onto each press nut 25, the convex shape of the press nuts 25 ensures a predetermined insulating space.
As shown in Figure 5, a through hole 26 is formed in the mounting portion 11, penetrating vertically, and the wiring extending from the power supply board 20 passes through the through hole 26 to the side of the underside 11B without passing outside the power supply cover case 22, and is connected to the light source portion 12.

As shown in Figure 4 above, the power supply cover case 22 of this embodiment comprises a case body 27 and a terminal block cover 28.

The case body 27 is a bottomless box, and as shown in Figure 6, the left and right side surfaces 29 have their lower ends bent into an L shape to form fixing pieces 30 for screwing to the mounting part 11. Inside the case body 27, a terminal block mounting piece 31 is provided approximately parallel to the left side surface 29. The terminal block 21 is fixed to this terminal block mounting piece 31 in a position close to the top surface 22A of the case body 27.

In the lighting fixture 1 of this embodiment, terminal block mounting pieces 31 are provided in two locations inside the case body 27, on the front surface 32 side and on the back surface 33 side (see Figure 7). A terminal block 21 for input to the power supply unit 8 is fixed to one of the terminal block mounting pieces 31, and a terminal block 21 for a dimming control line is fixed to the other terminal block mounting piece 31. Note that if light control such as dimming is not required, the other terminal block 21 does not need to be provided.

In the case body 27 of this embodiment, the terminal block mounting piece 31 is formed by bending the left ends of the front face 32 and rear face 33 in an L-shape toward the inside of the case body 27, thereby forming openings 34 (see Figures 8 and 9) at the left ends of the front face 32 and rear face 33. These openings 34 allow heat from the case body 27 to be efficiently dissipated to the outside. Furthermore, as shown in Figures 4 and 6, the openings 34 on the front face 32 and rear face 33 are connected to each other, forming a through passage A (see Figure 6) extending in the front-to-rear direction inside the case body 27.

As shown in Figures 4 and 6 above, the terminal block cover 28 is fixed to the left side surface 29 of the case body 27 by a fulcrum screw 28A, allowing it to rotate freely in the direction of arrow B. As shown by the dashed line in Figure 7, a notch 14A may be provided in part of the arm connecting piece 14 so that the head of the fulcrum screw 28A is completely visible in side view and not hidden by the arm connecting piece 14. Providing the notch 14A makes it easier for workers to use a screwdriver to tighten the fulcrum screw 28A to prevent the terminal block cover 28 from rotating when installing the lighting fixture 1.

The terminal block cover 28 conceals the terminal block 21 by covering both the sides and the top of the opening 34, and by leaving the front (rear) side of the opening 34 open, ventilation is ensured inside the case body 27. Furthermore, all openings 34 face the front and rear of the device body 4 and are positioned so as not to face any of the arm connecting pieces 14, ensuring sufficient ventilation.

The light source unit 12 provides illumination using light-emitting elements as a light source, and as shown in Figures 5 and 6, it includes a light source board 42 on which multiple LEDs 40, which are an example of light-emitting elements, are mounted, and a front globe 44, which is a cover member that covers the light source board 42.
The light source substrate 42 is a substantially rectangular metal substrate with excellent thermal conductivity, and is fixed with screws in a state where the entire surface of the light source substrate 42 is in contact with the lower surface 11B of the mounting portion 11 of the light source substrate mounting plate 10, with an insulating sheet with excellent thermal conductivity sandwiched therebetween. The lower surface 11B of the mounting portion 11 is provided with an appropriate number of half pierces (also called dowels) for positioning the light source substrate 42.

As shown in FIG. 4, the light source board 42 has wiring holes 43 opening at positions that communicate with the through holes 26 of the mounting portion 11. Wiring extending from the power supply board 20 passes through the wiring holes 43 and is pulled out to the mounting surface of the light source board 42 and connected to the light source board 42. Appropriate bushings are fitted into the through holes 26 and wiring holes 43 to protect the wire coating. It is preferable to use bushings that can seal the through holes. A resin substrate may also be used for the light source board 42. If a resin substrate is used for the light source board 42, the light source board 42 may be attached to the underside 11B of the light source board mounting plate 10 via thermal grease rather than a thermal sheet.

A large number of LEDs 40 are arranged on the mounting surface of the light source substrate 42, and light from each LED 40 is incident on the opposing front globe 44. The color (wavelength) of light emitted by each LED 40 is appropriate, and in this embodiment, white light is used.
The LEDs 40 are arranged on the mounting surface of the light source substrate 42, avoiding a predetermined range including the center thereof.

The front globe 44 is a thin, open-top box that covers the light source board 42. It is made of a translucent resin or glass material and is fixed with screws to the underside 11B of the mounting part 11. The entire surface of the front globe 44 is milky white, and by scattering the light from the light source part 12 as it passes through, it reduces the visibility of uneven illumination and bright spots of the LEDs 40 reflected on the front globe.

As shown in Figure 4 above, the arm 6 is a roughly U-shaped member made of a highly thermally conductive material. It integrally comprises a pair of support bar sections 50 extending parallel to each other and a connecting bar section 51 extending perpendicular to the support bar sections 50 and connecting the upper ends 50A of the support bar sections 50.

The connecting bar portion 51 is provided with a plurality of fixing holes 52, and is fixed to the ceiling surface (installation surface) by passing bolts through the appropriate fixing holes 52. In addition, a fastening hole 53 and an arc hole 54, which is an elongated hole in an arc shape centered on the fastening hole 53, are provided on the side of the lower end portion 50B of each support bar portion 50. The arm 6 is fixed to the arm connecting piece 14 of the light source board mounting plate 10 by passing bolts 15 through the fastening holes 53 and the arc hole 54. When fixing, the light source board mounting plate 10 is fixed at a desired angle by rotating the light source board mounting plate 10 within the range of the elongated holes of the arc hole 54 around the fastening hole 53 as a fulcrum.
Appropriate devices such as various sensors, such as an illuminance sensor, and communication devices may be fixed to the support bar portion 50 .

In the lighting fixture 1, the upper surface 11A of the fixture body 4 is not provided with heat dissipation fins that are provided in conventional general high ceiling lighting fixtures, and heat generated by the LEDs 40 is efficiently dissipated without providing such heat dissipation fins.
More specifically, the heat generated by the LEDs 40 is transmitted to the light source board mounting plate 10 via the light source board 42. As shown in Figures 1 and 2, the top surface 11A of the mounting portion 11 of the light source board mounting plate 10 and the arm connecting pieces 14 on both sides thereof are exposed to the outside, and the heat generated by the LEDs 40 is dissipated to the outside from the top surface 11A and the arm connecting pieces 14.

As described above, each arm connecting piece 14 is integrally formed by bending the edges on both sides of the light source board mounting plate 10 that sandwich the mounting portion 11. In conventional lighting fixtures, the mounting portion 11 and the arm connecting piece 14 are made of separate members, and the amount of heat transferred is reduced due to contact resistance between them. The arm connecting piece 14 of this embodiment is approximately 3 mm thick, ensuring a sufficient cross-sectional area for a heat conduction path. This reduces the thermal resistance between the upper surface 11A of the mounting portion 11 and each arm connecting piece 14, allowing a large amount of heat to be quickly transferred to the end of the arm connecting piece 14.
This allows for good heat dissipation performance without providing separate heat dissipation fins on the upper surface 11A of the mounting portion 11. In addition, since the heat dissipation fins are no longer necessary, the fixture body 4 can be made lighter.

As described above, in the lighting fixture 1 of this embodiment, the arm 6 is made of a highly thermally conductive material, and heat is conducted from the arm connecting piece 14 to the arm 6, and heat is dissipated from the entire arm 6, further improving heat dissipation performance. In addition, as shown in Figure 6, the lower end 50B of each support bar portion 50 of the arm 6 is fixed directly (without any intervening member) to the arm connecting piece 14 in surface contact. This reduces thermal resistance between the arm connecting piece 14 and the arm 6, increasing the amount of heat dissipation from the arm 6, thereby achieving even better heat dissipation performance.
In this embodiment, the arm 6 is made of a member made of SPCC (cold rolled steel plate) and having a thickness of about 2 mm.

7 is a left side view of the lighting fixture 1, FIG. 8 is a front view of the lighting fixture 1, and FIG. 9 is a rear view of the lighting fixture 1. As shown in FIG.
As shown in FIG. 8, the arm connecting piece 14 is formed so that its maximum height Hamax is approximately the same as the height Hb of the power supply device 8 or slightly lower than the height Hb of the power supply device 8 by a few millimeters.
The internal space of the power supply device 8 must be large enough to keep the temperatures of the various components on the power supply board 20 and terminal block 21 within a specified temperature range, and it is also necessary to ensure an insulating distance between the power supply board 20 and the power supply cover case 22, and between the power supply board 20 and the upper surface 11A of the mounting portion 11. The height Hb of the power supply device 8 (power supply cover case 22) in this embodiment is set to the minimum height that satisfies these requirements.
By making the maximum height Hamax of the arm connecting piece 14 approximately the same as the height Hb of the power supply unit 8, the amount of protrusion of the device main body 4 upward from the upper surface 11A can be limited to the height Hb of the power supply unit 8, and the heat dissipation effect of the arm connecting piece 14 can be maximized within the limit of that protrusion amount.

Also, as shown in Figure 8, the distance M from the power supply unit 8 (power supply cover case 22) to the connecting bar portion 51 of the arm 6 is greater than the height Hb of the power supply unit 8, ensuring sufficient space between the ceiling surface on which the arm 6 is installed and the power supply unit 8. It is preferable that the position of the power supply board 20 within the power supply cover case 22 be higher than half the height Hb of the power supply unit 8.

In this embodiment, the height Hb of the power supply unit 8 is 63 mm, and the distance M is 100 mm. The maximum height Hamax of the arm connecting piece 14 is 62 mm.

7, each arm connecting piece 14 in this embodiment is formed in a substantially triangular shape (a substantially isosceles triangle in this embodiment) with a vertex (maximum height Hamax) at the center of the instrument body 4. In this specification, a substantially triangular shape refers to a shape in which each vertex of the triangle is chamfered.
Furthermore, in the light source board mounting plate 10, the maximum length La in the front-to-rear direction of each arm connecting piece 14 is shorter than the overall length Lb of the mounting portion 11 in the front-to-rear direction. This configuration allows the four corners of the mounting portion 11 to be rounded. This prevents problems even if a person's hand touches the corners of the mounting portion 11 during transportation or installation of the lighting fixture. In this embodiment, the maximum length La corresponds to the length of the base of the arm connecting piece 14, i.e., the length of the connection portion between the mounting portion 11 and the arm connecting piece 14, and this maximum length La is in the range of approximately 65% to 90% of the overall length Lb of the mounting portion 11.

Each arm connecting piece 14 has multiple through-holes 61 that penetrate from the front to the back to ensure ventilation. The through-holes 61 are approximately 10 to 20 mm wide from the outer periphery, taking into account the heat dissipation area of the arm connecting piece 14 as a heat dissipation fin and the strength of the arm connecting member. In this embodiment, the ratio of the total opening area of the through-holes 61 to the side area of each arm connecting piece 14 (opening rate) is approximately 10 to 20%. Because the rigidity of the arm connecting piece 14 affects the earthquake resistance of the device itself, the thickness (plate thickness) of the arm connecting piece 14 must not be too thin in an effort to achieve ventilation and lightweight construction. A fall prevention wire can also be passed through the through-holes 61.

In this way, the arm connecting piece 14 is formed in a roughly triangular shape, its maximum length La is shorter than the overall length Lb of the mounting portion 11, and multiple through-holes 61 are provided, thereby reducing the weight of the arm connecting piece 14.

Furthermore, the through-holes 61 of the arm connecting pieces 14 improve the ventilation in the left-right direction of the device main body 4, thereby improving the heat dissipation performance of the upper surface 11A between the pair of arm connecting pieces 14 and the power supply unit 8. In a side view, each through-hole 61 widens vertically the closer it is to the center of the device main body 4, thereby increasing the opening area, thereby ensuring sufficient ventilation between the power supply unit 8 located in the center and the arm connecting pieces 14.
Each through-hole 61 may be used to fasten an appropriate member such as a fall prevention wire or a guard member for protecting the front globe 44 .

Various parameters such as the side area of the arm connecting piece 14, the total opening area of each through-hole portion 61, the maximum length La, the total length Lb of the mounting portion 11, and the area of the top surface 11A of the mounting portion 11 can be optimized for each light output of the light source portion 12 according to the required heat dissipation performance.

This embodiment provides the following advantages:

In the lighting fixture 1 of this embodiment, the light source board mounting plate 10 is provided with arm connecting pieces 14 formed by bending upward into an L-shape each of the edges on both sides of the mounting portion 11 to which the light source board 42 is attached, and an arm 6 is connected to each arm connecting piece 14.

With this lighting fixture 1, heat generated by the LEDs 40 and transmitted to the light source board mounting plate 10 via the light source board 42 can be dissipated to the outside from the upper surface 11A of the mounting portion 11 and the arm connecting pieces 14 on both sides thereof. Furthermore, because each arm connecting piece 14 is integrally formed with the mounting portion 11 by bending, the thermal resistance between the upper surface 11A of the mounting portion 11 and each arm connecting piece 14 is small, and the heat transmitted from the light source board 42 to the mounting portion 11 is transmitted directly and smoothly by thermal conduction to each arm connecting piece 14, allowing for efficient heat dissipation.
This allows for good heat dissipation performance to be achieved without providing separate heat dissipation fins on the upper surface 11A of the mounting portion 11, which can be prone to deterioration due to dust accumulation, etc. Furthermore, eliminating the need for heat dissipation fins allows for the weight of the fixture body 4 to be reduced.

In conventional high-ceiling lighting fixtures, there is almost no temperature rise due to heat transfer from the LED at the part of the housing where the arm is attached. In other words, in conventional high-ceiling lighting fixtures, the arm and arm attachment member do not contribute to the heat dissipation of the lighting fixture. On the other hand, in lighting fixture 1 of this embodiment, a temperature rise was confirmed in arm connecting piece 14 and arm 6 while the fixture was turned on, which shows that arm connecting piece 14 and arm 6 contribute to the heat dissipation of lighting fixture 1.

In the lighting fixture 1 of this embodiment, each arm connecting piece 14 is provided with multiple through-holes 61, which allows for a lighter fixture body 4 and ensures ventilation in the left-right direction of the fixture body 4. It can also be used to secure appropriate components, such as a fall prevention wire or a guard member that protects the front globe 44.

In the lighting fixture 1 of this embodiment, the maximum length La of the arm connecting piece 14 in the front-to-rear direction of the light source board mounting plate 10 is shorter than the total length Lb of the mounting portion 11 in the front-to-rear direction, making it possible to further reduce the weight of the fixture body 4.

In the lighting fixture 1 of this embodiment, each arm connecting piece 14 is approximately triangular in shape, making it possible to make the fixture body 4 lighter than when the maximum height Hamax is the same but the fixture body is rectangular in side view.

In the lighting fixture 1 of this embodiment, the arm 6 is in surface contact with the arm connecting piece 14, so heat is smoothly transferred from the arm connecting piece 14 to the arm 6, allowing heat to be efficiently dissipated from the entire arm 6, achieving even higher heat dissipation performance.

In the lighting fixture 1 of this embodiment, the maximum height Hamax of the arm connecting piece 14 is less than the height Hb of the power supply unit 8 mounted on the upper surface 11A of the mounting portion 11, so the amount of upward protrusion of the fixture body 4 from the upper surface 11A can be limited to the height Hb of the power supply unit 8.

In the lighting fixture 1 of this embodiment, the power supply board 20 in the power supply unit 8 is fixed to the top surface 22A inside the power supply cover case 22, thereby providing insulation from the mounting part 11 and minimizing the impact of heat generated by the power supply board 20 on the mounting part 11.

In the lighting fixture 1 of this embodiment, the power supply unit 8 has openings 34 that communicate with the interior at positions that do not face each of the arm connecting pieces 14, ensuring good ventilation.

The above-described embodiment merely illustrates one aspect of the present invention, and any modifications and applications are possible without departing from the spirit and scope of the present invention.

(Variation 1)
In the above-described embodiment, the light source unit 12 is rectangular in bottom view, but a light source unit 112 may be configured to be substantially square in bottom view, as in the lighting fixture 100 shown in Fig. 10. In this case, the mounting unit 11 of the light source board mounting plate 10 may also be square in bottom view to match the light source unit 112. By shortening the longitudinal direction of the light source unit 12 (light source board 42) that is rectangular in bottom view, a lighting fixture 100 with lower light output than the lighting fixture 1 can be easily realized.

(Variation 2)
A plurality of light source units 12 may be provided on the underside 11B of the light source board mounting plate 10. For example, as in a lighting fixture 200 shown in Fig. 11(A), two square light source units 112 in bottom view shown in Fig. 10 may be provided side by side on the underside 11B of the light source board mounting plate 10. Furthermore, as in a lighting fixture 300 shown in Fig. 11(B), for example, two light source units 12 included in the lighting fixture 1 of the above-described embodiment may be provided side by side on the underside 11B of the light source board mounting plate 10.
By arranging a plurality of light source units 12, 112, it is possible to easily realize lighting fixtures 200, 300 with a greater light output than lighting fixture 1.

(Variation 3)
When multiple light source units 12, 112 are provided on the light source board mounting plate 10, a power supply unit 8 may be provided for each light source unit 12, 112 side by side on the upper surface 11A of the light source board mounting plate 10, as in the lighting fixture 400 shown in Fig. 12. In this case, a connecting member 480 may be provided between the two power supply units 8 to fix the relative positions of the power supply units 8 and also serve as a wiring cover. Furthermore, in a lighting fixture 400 provided with multiple power supply cover cases 22, power supply lines can be routed between the terminal blocks 21 of the two power supply cover cases 22 through the through passage A during assembly of the fixture. Dimming control lines can also be routed internally in a similar manner.

(Variation 4)
13, a lighting fixture 500 may be provided with a guard member 585 that protects the light source unit 12. Support pieces 586 may be fixed to each arm connecting piece 14, and the guard member 585 may be supported by each support piece 586. By forming each support piece 586 from a highly thermally conductive material, like the arm 6, the heat dissipation performance can be further improved.

(Variation 5)
As shown in FIG. 14 , the lighting fixture 600 may be configured such that the power supply 8 is provided above (a gap is provided between) the upper surface 11A of the mounting portion 11 of the light source board mounting plate 10, thereby providing a space Q between the mounting portion 11 and the power supply 8. Specifically, the power supply 8 is supported by a support portion 70 provided on the upper surface 11A of the light source board mounting plate 10. The support portion 70 is provided away from the arm 6 and the arm connecting piece 14, and supports the power supply 8 so as to separate the power supply 8 from the light source board mounting plate 10 in the vertical direction. Note that no structure such as a heat dissipation fin is provided between the power supply 8 and the light source board mounting plate 10. This improves the heat dissipation performance of the upper surface 11A of the mounting portion 11, thereby achieving even higher heat dissipation performance.

(Variation 6)
In cases where the light output of the lighting fixture 1 is relatively small, or where the light emitting efficiency of the LED 40 is high and the amount of heat generated is small relative to the area of the mounting portion, the area of the arm connecting piece 14 can be further reduced.
15 and 16, the width of the rising portion 90 of the arm connecting piece 14 is the maximum length La of the arm connecting piece 14 in the front-to-rear direction, and a height of approximately 10 mm is ensured that it is 65% or more of the total length Lb of the mounting part 11 in the front-to-rear direction. The width Lc of the arm connecting part 91 above the rising portion 90 may be a rectangular shape with approximately the same dimensions as the arm 6.
However, rather than simply forming a 90-degree corner at the boundary between the rising portion 90 and the arm connecting portion 91, it is preferable to provide a connecting region 92, such as a sloped or rounded concave curved surface, to alleviate stress concentration. When a sloped surface is provided, the dimensions of these connecting regions 92 should be set so that one side of an imaginary triangle when the arm connecting piece 14 is viewed from the side is at least 10 mm. For example, in the lighting fixture 700 of FIG. 15, the vertical dimension of the imaginary triangle is 10 mm and the horizontal dimension is 17.3 mm. In the case of a concave curved surface, it is preferable that the radius of the imaginary arc when the arm connecting piece 14 is viewed from the side is 10 mm or more. For example, in the lighting fixture 800 of FIG. 16, a curve with a radius of 10 mm is provided.
When these configurations are adopted, the arm connecting piece 14 can no longer be said to be substantially triangular, but they all have in common the fact that the dimension of the upper side of the arm connecting piece 91 is shorter than the dimension of the lower side formed by bending from the mounting portion 11. With such a shape, the amount of heat transferred from the mounting portion 11 in the light source board mounting plate 10 can be transferred to the arm connecting piece 14 by thermal conduction, and a stable mounting state can be maintained even when the lighting fixture is installed on the ceiling by the arm 6.

(Other Modifications)
The power supply device 8 may be provided separately from the lighting fixture 1 .
The lighting fixture 1 may be installed on a wall surface as well as on a ceiling surface.
The material of the light source board mounting plate 10 and the arm 6 can be any alloy or metal that has high thermal conductivity required for dissipating heat from the light source unit 12 and can achieve the required rigidity.
In the above-described embodiments, unless otherwise specified, directions such as horizontal and vertical, various numerical values, and shapes do not intentionally exclude the surrounding ranges of these directions and numerical values, and approximate shapes, but include the surrounding ranges and approximate shapes (so-called equivalent ranges) as long as they produce the same action and effect and do not deviate from the critical meaning of the numerical values.

1, 200, 300, 400, 500, 600, 700, 800 Lighting fixture 4 Fixture body 6 Arm 8 Power supply device 10 Light source board mounting plate 11 Mounting portion 12, 112 Light source portion 14 Arm connecting piece 20 Power supply board 22 Power supply cover case 22A Top surface 34 Opening 40 LED (light emitting element)
42 Light source substrate 61 Through-hole portion Hamax Maximum height of arm connecting piece Hb Height of power supply device La Maximum length of arm connecting piece Lb Total length of mounting portion M Distance

Claims (2)

a light source substrate on which a plurality of light emitting elements are mounted;
a plate-shaped light source substrate mounting plate having high thermal conductivity and having the light source substrate mounted on its underside ;
a power supply device including an electric circuit for generating power to be supplied to the light source board;
an arm that supports the light source board mounting plate and has high thermal conductivity;
Equipped with
the light source substrate is attached in a state where the entire surface of the light source substrate is in contact with the lower surface of the light source substrate attachment plate,
The support portion that supports the power supply device is formed in a box shape with one side open,
the support portion is installed on the upper surface of the light source board mounting plate such that an open surface faces the upper surface of the light source board mounting plate and the open surface is closed by the upper surface of the light source board mounting plate,
the support portion supports the power supply device so as to separate the power supply device from the light source board mounting plate in the up-down direction by attaching the power supply device to a surface of the support portion that faces the open surface,
the power supply device is suspended above the upper surface of the light source board mounting plate to provide a gap therebetween,
the light source board mounting plate has no heat dissipation fins in the gap;
A lighting fixture characterized by: the power supply device has a power supply board,
The lighting fixture according to claim 1, characterized in that the power supply board is fixed to the surface of the support part facing the open surface inside the box-shaped support part so as to be spaced apart from the light source board mounting plate.