JPS60100390A - Supporting structure of ceramic heater - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ceramic intake air heater that heats intake air in an intake system when starting a direct-drive diesel engine, for example, mainly in cold weather. Support structure for heating element.

(Prior Art) In the prior art, a plurality of metal wires made of ζFe-Cr yr metal resistance material were used as a heating element in the form of a coil or the like.

However, in recent years, attention has been paid to ceramic materials, which are superior to metal materials in terms of heat resistance and oxidation resistance, as materials for heating elements. However, since ceramic material is a brittle material, if this ceramic heating element is rigidly supported at two or more points, the heating element will be destroyed due to thermal expansion during heat generation, and the heating element will be supported at one point. If it is supported by itself, there are problems such as its vibration resistance is weak and it cannot be used in places with strong vibrations, such as when used in places with strong vibrations, such as in the intake air heater of a car.

(Object of the Invention) In order to solve the above-mentioned drawbacks, the present invention provides a ceramic heating element in a metal frame, fixes one end of the heating element to the metal frame, and By fixing the other end to a part of the cushion member and fixing a part of the shoe member to the metal frame, the cushion member absorbs the thermal expansion of the heating element that occurs when the heating element generates heat. Then, leave!
) An object of the present invention is to provide a support structure for a ceramic heating element that prevents damage to the ceramic heating element and can be used even in places with strong vibrations since the heating element is fixed to a metal frame via a shoe member. That is.

(Embodiments) The present invention will be described below with reference to embodiments shown in FIGS. 1, 2, 3, and 4. In FIGS. 1 and 2, for example, ``iN and 3 i 3 N
Ceramic planar heating elements 1 and 2 consisting of 4 are
The planar heating element 1 is installed inside the metal frame 5 through a gap. A notch portion 24 is provided at one end of 2.

One end of the planar heating element 1.2 is fixed to the metal frame 5 with a bolt 4, with an insulating spacer 3 sandwiched between the planar heating element 1 and the planar heating element 2. Also, between the planar heating element 2 and the metal frame 5, there is an insulating spacer 1 on the metal frame side.
8, and one end of a stainless steel I-shaped metal plate 14 is sandwiched on the sheet heating element side. Further, a stainless steel metal plate 20 is provided between the bolt 4 and the planar heating element 1. In addition, on both sides of the end of the planar heating element 1゜2, there is a platinum coated part 19 which is coated with a platinum paste and dried to ensure good electrical conductivity.The other end of the L-shaped gold plate 14 is are fixed to the metal frame 5 by bolts 15 and nuts 17 together with an insulating spacer 16.The other ends of the sheet heating elements 1 and 2 are connected between the sheet heating elements 1 and 2. A conductive spacer 8 is held between the bolt 6 and the nut 7. Also, between the bolt 6 and the sheet heating element 1 and between the nut 7 and the sheet heating element 2, a stainless metal plate 20 is provided. In FIG. 3, one end of a metal leaf spring 9 is attached to the conductive spacer 8 with a bolt IO.The other end of the leaf spring 9 is
Together with an insulating spacer 11, it is fixed to the metal frame 5 with bolts 12 and nuts 13.

Note that the leaf spring 9 is attached to the metal frame 5 by an insulating spacer 11.
A gap is provided between the sheet heating elements 1 and 2 by the washer 25, and a gap is provided between the sheet heating elements 1 and 2 by the washer 25. The bolts 12 and 15 also serve as terminals to which battery voltage is applied.

First, the operation of the above configuration will be explained.

Bolt 12 which is the terminal part of intake air heater 21
When the engine is started at a low temperature, the battery voltage C is applied to the control circuit 11f%, a relay, etc. (not shown) to the pole 115.

There are two ways for the current to flow.The first method is that the battery voltage is applied to the bolt 12 and the current flows through the leaf spring 9. bolt 1
0□ Through the conductive spacer 8, the planar heating elements l and 2
flows to The current flowing through the C-shaped heating element 1 flows through the bolt 4 to the metal frame 5 and is grounded. Also,
The current flowing through the planar heating element 2 flows to the bolt 15 of the all-metal plate 14. At this time, tighten the bolt 15
put.

In the second method, the battery voltage is applied to the bolt 15, the current flows through the L'W metal Fii 14 to the sheet heating element 2, from the conductive spacer 8 to the sheet heating element 1, and the current flows through the bolt 4. It flows through the metal frame 5 and is grounded.

At this time, the bolt 12 is left open. By passing current in this way, the planar heating elements 1 and 2 generate heat, which increases the intake air of the engine.

The planar heating elements 1 and 2 that generate heat as described above undergo thermal expansion due to the heat generation, but with the above-described structure, the elongation of the planar heating elements 1 and 2 caused by thermal expansion is suppressed by the temporary spring 9. , to absorb the elongation and prevent damage to the planar heating element 1.2, and to prevent the plate spring 9 from bending in the vertical direction in FIG. 1 and in the vertical direction in FIG. It has a structure that can withstand severe vibrations.

By the way, the plate spring 9 provided between the planar heating element 1.2 and the metal frame 5 is removed, and the metal frame 5 is fixed with bolts or the like.
The ceramic (T i N
+S i 3N4) When using a sheet heating element 1°2, the coefficient of thermal expansion is 3X10-6/°C1 Young's modulus is approximately 20
,000kg/-, so for example, t o o o
For a temperature rise of 'c, a thermal stress of 60 kg/- is generated, and even if heat is generated uniformly, the planar heating element 1 having the opening 23 as in this embodiment. In No. 2, the structural portion 26 cannot withstand the thermal stress and easily buckles and breaks.

Also, if you do not attach the leaf spring 9 and attach a lead wire directly to that part to make it in a so-called free state (cantilever structure), it may break due to thermal expansion due to heat generation. However, the vibration resistance is not sufficient. Figure 5 shows an example of the vibration test results. Sine wave excitation with an excitation force of 10 G was performed, and the displacement signal (effective value) from the acceleration pickup attached to the It is centered on this.

The broken line in the figure shows the case where the plate spring 9 is eliminated and a cantilevered structure is used, and there is a resonance point around 370 Hz. In this case, when the excitation force is increased to 15G, It was broken in 1n pieces. However, by attaching the leaf spring 9, the resonance characteristics changed as shown by the solid line, the resonance frequency increased to 690]1z, and the displacement at the resonance point also decreased. Therefore, the structure has a vibration resistance strength of 1IiJ even with an excitation force of 40G.

In the above-mentioned embodiment, the planar heating element 1゜2 is fixed at the lug with the pin 14, and the leaf spring 9 is attached to the metal frame 5.
The heating element 1.2 was fixed to the mounting part 27 of the metal frame 5 at two places with bolts 4 in Fig. 6, and the battery voltage was adjusted to the right side in Fig. 1. Since the bolt 12 serving as the terminal for applying voltage is located below the metal frame 5 in FIG. 6, the plate spring 9 has an L-shape. In addition, in Fig. 6, the sheet heating element is 1
Although only one sheet is visible, the sheet heating element 2 is hidden by the sheet heating element I.

In addition, in FIGS. 7 and 8, the shape of the leaf spring 9 is shown in FIG.
By doing as shown in the figure, the planar heating element 1,
It is combined with 2. Note that in FIG. 7, the planar heating element 2 is hidden by the planar heating element 1, as in FIG. 6.

Moreover, FIGS. 9 and 10 show still another embodiment regarding the shape of the leaf spring, in which the leaf spring 9 is made smaller and the bolts 12 for fixing the leaf spring 9 to the metal frame 5 are fixed to the metal frame 5. It is stored internally.

So far, bolt everything on each fixed part.

I went with Natsu, but the metal frame 5 and the 14 type metal plate 14
The flat heating element 1.2 and the metal frame 5 may be fixed by a fixing beam bed between the leaf spring 9 and the metal frame 5, and the sheet heating element 1.2 and the metal frame 5 can be fixed by inserting a pin from the top of the sheet heating element It is also possible to weld at the lower part of the frame 5 and ζ.

Regarding the planar heating element 1.2, the shape of +1110 is an elongated oval shape in each embodiment, but the shape is not limited to this and may be any shape that allows ventilation, such as a circle.

Further, although the heating element has been made into a planar shape, the heating element may also be formed by using several lamic rods and fixing both ends of the rods to a metal plate by bonding or the like.

Further, in each of the embodiments, the number of planar heating elements is two, but the number is not limited to this and may be one.

Regarding the leaf spring, in each embodiment, the leaf spring 9 was provided only at -1lil, but it may be provided at both ends, or -Of! ■(Only a hard one was installed, but there were a few membranes on one end.) ``It doesn't matter.

In addition, the ends of the planar heating element 1.2 are coated with platinum, and the heating element is fixed to the metal frame via a cushion member, so it can be used even in places with strong vibrations. effective.

[Brief explanation of drawings]

FIG. 1 is a front view showing one embodiment of the present invention, and FIG. 2 is a front view showing an embodiment of the present invention.
FIG. 3 is a cross-sectional view taken along line A-A′ in FIG. 1, FIG. 3 is a cross-sectional view taken along line B-B′ in FIG. 2, and FIG. FIG. 5 is a graph showing an example of the vibration test results used for performance comparison between the case where the plate spring of the present invention is provided and the case where a cantilever structure is provided, and FIG. 6 is a graph showing an example of the vibration test results used for performance comparison. FIG. 7 is a front view showing another embodiment of the plate spring of the present invention, and FIG. 8 is a front view of another embodiment of the plate spring of the present invention. FIG. 9 is a perspective view of the spring, FIG. 9 is a front view showing still another embodiment of the leaf spring of the present invention, and FIG. 10 is a sectional view taken along line cc' in FIG. ■, 2... Heating element, 5... Metal frame, 9... Leaf spring forming the cutlet member. Registration of Procedures November 9, 1980 Commissioner of the Japan Patent Office Relationship with Case 1 of Person Who Amends Display Ceramic Heating Element Support Structure 3 Case Patent Applicant 1-1 Showa-cho, Kariya City, Aichi Prefecture (426) Nippondenso Co., Ltd. Representative Kengo Toguchi J. 4th Director Osamu 1-1-5 Showa-cho, Kariya-shi, Aichi Prefecture 448 Column for detailed explanation of the invention in the specification subject to the amendment. 6. Contents of amendment ill Add a separate sentence after page 9 of the specification. 19, but the coating material here is not limited to platinum, and other materials such as silver or nickel that improve conductivity may be used. In each of the embodiments described above, the leaf spring 9 has been used as the cushion member, but the cushion member is not limited to the leaf spring. Alternatively, a corrugated metal plate may be fixed between the planar heating element 1.2 and the metal frame 5 to serve as a cushion member. The plate spring 9 is not limited to any member as long as it absorbs the F8 expansion during heat generation. (Effect of the invention)

Claims (1)

[Claims] A ceramic heating element is provided in the metal frame through a gap with the metal frame in a ventilable state, one end of the back of both ends of the heating element is fixed to the metal frame, and the other end of the heating element is fixed to the metal frame. -1415 of the shoe 21 foot member, and
A support structure for a ceramic heating element, characterized in that a part of the 9F member is fixed to the metal frame.