JP2000121168A - Electric hot water device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the deterioration of boundary parts between the pressing parts and the protruding parts of a heater attaching part and prevent water leakage from the boundary parts. SOLUTION: The tank body 12 of a hot water tank 11 is provided with a heater insert hole 16 into which a heater is inserted. In the peripheral edge part of the heater insert hole 16, a heater attaching part 17 is provided for attaching a heater supporter supporting the heater. The heater attaching part 17 is provided with pressing parts 23 for pressing to the inner surface side of the tank body 12 at both edge parts along the axial direction of the tank body 12 and protruding parts 24 protruding to the outer surface side of the tank body 12 at both edge parts along the circumferential direction of the tank body 12. The heater attaching part 17 is provided in a flat form by the pressing parts 23 and the protruding parts 24. A plurality of bolts 26 are provided at positions avoiding the boundary parts 25 of the pressing parts 23 and the protruding parts 24 on the outer surface of the heater attaching part 17 so that force generated by a pressure fluctuation in the hot water tank 11 is prevented from being directly applied to the boundary parts 25 through the bolts 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater, and more particularly, to a structure for mounting a heater disposed in a hot water tank.

[0002]

2. Description of the Related Art Conventionally, in an electric water heater, for example,
As described in Japanese Patent Application Laid-Open No. H8-100954, a hot water tank for boiling hot water is provided, and a heater mounting hole is formed in a part of a cylindrical tank body of the hot water tank. A flange is welded along the periphery of the hole, a heater is inserted into the tank body through the heater mounting hole, and a flat disk-shaped heater support supporting the heater is joined to the flange via the packing and bolts are formed. The heater mounting hole is stopped so that the heater mounting hole is liquid-tightly closed by the heater support.

However, when the flange is welded to the heater mounting hole of the tank body as described above, the welded portion is located in the hot water tank, and corrosion at the welded portion due to contact with water or hot water in the hot water tank. It is likely to occur, and this corrosion may cause water leakage or the like.

Therefore, as shown in FIG. 9 which shows a front view of the heater mounting hole 2 of the hot water tank 1, a plurality of bolts 3 are fixed to the outer surface of the heater mounting hole 2 of the tank body 1a by stud welding. However, by adopting a configuration in which the heater support is attached via the packing with the bolts 3, the problem of corrosion at the welded portion can be solved since the welded portion is not located in the hot water tank 1.

In this case, the heater mounting portion 4 which is the peripheral portion of the heater mounting hole 2 of the tank body 1a may be planar in order to mount the flat disk-shaped heater support in a liquid-tight manner via the packing. It is necessary, and for this reason, at both edges along the axial direction of the tank body 1a (vertical direction in FIG. 9), the press-in portions 5 which are pressed from the outer surface side to the inner surface side of the tank body 1a are formed, Circumferential direction of tank body 1a (Fig. 9
The left and right sides of the tank body 1a are formed with protrusions 6 protruding from the inner surface side to the outer surface side of the tank body 1a by press molding. Is formed. The pushing portion 5 and the protruding portion 6 are simultaneously formed by press forming from the outer surface side and the inner surface side of the tank body 1a, and four boundary portions 7 between the pushing portion 5 and the protruding portion 6 are formed by press forming. Neither pushing nor protruding, the peripheral surface shape of the tank body 1a is left as it is.

A plurality of bolts 3 are stud-welded to the outer surface of the heater mounting portion 4 at several locations including four boundaries 7 between the pushing portion 5 and the projecting portion 6.

[0007]

As described above, the four boundary portions 7 between the pushing portion 5 and the protruding portion 6 are neither pushed nor protruded by press molding, and the peripheral surface shape of the tank body 1a remains unchanged. Since it is left, the strength is weaker than that of the pressing portion 5 and the protruding portion 6 which are press-formed in an uneven shape.
This is a so-called sagging portion that is easily deformed by an external force.

The water pressure in the hot water tank 1 is applied to the heater support that closes the heater mounting hole 2, and this water pressure is received by the heater mounting portion 4 via a plurality of bolts 3. In the hot water tank 1, pressure fluctuations are repeated due to a change in water pressure due to opening and closing of the faucet by a stop-stop method, a change in pressure according to the water temperature such as expansion accompanying boiling, and the like. Therefore, the force accompanying the pressure fluctuation in the hot water tank 1 is repeatedly applied to the heater mounting portion 4 via each bolt 3.

As in the prior art, if the bolt 3 is welded to the boundary portion 7 having a low strength and a sagging portion, the hot water tank 1
The force accompanying the pressure fluctuation in the inside
Directly and repeatedly, metal fatigue tends to occur relatively early in the vicinity of the bolt 3 at the boundary portion 7 even under normal use of the electric water heater, and this metal fatigue causes cracks and water leakage. There is a possibility that.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing points, and has been made in view of the above circumstances. The purpose is to provide a vessel.

[0011]

According to a first aspect of the present invention, there is provided an electric water heater including a hot water tank having a cylindrical tank body, a heater insertion hole provided in the tank body, and a peripheral portion of the heater insertion hole. A heater mounting portion is provided, which has a pushing portion pushed into the inner surface side of the tank body, has a projecting portion projecting to the outer surface side of the tank body, and has a heater mounting portion made flat by the pushing portion and the projecting portion. A plurality of bolts provided at positions on the outer surface of the heater mounting portion avoiding a boundary between the pushing portion and the protruding portion; and a heater inserted into the tank body through the heater insertion hole. And a heater support that is attached to the attachment portion via a bolt and closes the heater insertion hole. And, by providing a plurality of bolts at a position avoiding a boundary portion where the strength is weaker than the pushing portion and the protruding portion, that is, at a position where the strength is strengthened by forming the pushing portion and the protruding portion, Therefore, the force due to the pressure fluctuation in the hot water tank is not directly and repeatedly applied to the boundary portion via the bolt, and the deterioration of the boundary portion is reduced,
Prevents water leakage from borders.

The electric water heater according to a second aspect of the present invention is the electric water heater according to the first aspect, wherein the bolts are provided at regular intervals along the heater mounting portion. After being provided, the heater mounting portion and the heater support are evenly mounted to prevent water leakage from between the heater mounting portion and the heater support.

According to a third aspect of the present invention, in the electric water heater according to the first or second aspect, the welding seat is provided on the outer surface of the heater mounting portion in one of a concave shape and a convex shape,
The bolt is welded to the welding seat of the heater attachment part, and reinforces the heater attachment part.

According to a fourth aspect of the present invention, in the electric water heater of the first or second aspect, a reinforcing beat is provided at a position near the bolt of the heater mounting portion, and the heater mounting portion is reinforced. I do.

According to a fifth aspect of the present invention, in the electric water heater of the first or second aspect, the electric water heater has a plurality of insertion holes through which each bolt of the heater mounting portion is inserted, and each of the bolts is provided with each insertion hole. It has a ring that is fixed to the outer surface of the heater mounting portion in a state where it is inserted, and reinforces the heater mounting portion.

According to a sixth aspect of the present invention, in the electric water heater according to the first or second aspect, a ring fixed to an outer surface of the heater mounting portion is provided, and each bolt of the heater mounting portion is provided on the ring. It reinforces the heater mounting part.

According to a seventh aspect of the present invention, in the electric water heater according to the first or second aspect, a reinforcing beat is provided around a heater mounting portion of the tank body.
Reinforce the heater mounting part.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 3 show a first embodiment.

FIG. 3 is a schematic sectional view of the electric water heater.
Is a hot water tank, this hot water tank 11 has a vertically long, cylindrically formed tank body 12, and a tank end body 13 is integrated with upper and lower ends of the tank body 12, and is formed in a sealed shape. . As a material of the tank body 12 and the tank end body 13, for example, stainless steel which is resistant to corrosion is used.

The hot water tank 11 employs a hot water supply system of a first push-up type. A water supply pipe connected to a water pipe below the hot water tank 11 and supplied with tap water by a pressure from a water source. 14 is connected, and a hot water supply pipe 15 connected to a hot water supply place is connected to an upper portion.

A circular heater insertion hole 16 is formed on the lower side of the tank body 12.
An annular heater mounting portion 17 is formed at the peripheral portion of the heater. Then, a heater 18 is inserted into the warm water tank 11 from the heater insertion hole 16, and a flat disk-shaped heater support supporting the heater 18 is provided.
A heater 19 is mounted on the outer surface of the heater mounting portion 17 via an annular packing 20, and the heater insertion hole 16 is liquid-tightly closed by the heater support 19.

The heater 18 is rod-shaped, and its tip is bent downward so that the hot water can be heated on the bottom side in the hot water tank 11.

Next, FIG. 1 shows a heater insertion hole of the hot water tank 11.
2 (a) is a sectional view taken along the line AA of FIG. 1, FIG. 2 (b) is a sectional view taken along the line BB of FIG. 1, and FIG. C shows a sectional view.

An annular flange portion 21 protruding outward is formed at the peripheral edge of the heater insertion hole 16, and an annular concave portion 22 for fitting the packing 20 is formed on the outer peripheral side of the flange portion 21. An annular and substantially flat heater mounting portion 17 is formed on the outer peripheral side of the concave portion 22.

The heater mounting portion 17 is formed in a substantially planar shape for mounting a flat disk-shaped heater support 19 through a packing 20 in a liquid-tight manner, and is formed in an axial direction of the tank body 12 (FIG. 1).
1, that is, the BB cross section of FIG.
2B), a pressing portion 23 is formed at both edges along the circumferential direction of the tank body 12 by being pressed from the outer surface side to the inner surface side of the tank body 12 by press molding. (Left and right direction of FIG. 1, that is, FIG. 1A-A cross section,
2 (a) is shown in FIG. 2 (a). Projections 24 are formed on both edges along the inner side of the tank body 12 by press forming from the inner side to the outer side. The protrusion 24 forms the heater mounting part 17 in a substantially planar shape. The pushing portion 23 and the projecting portion 24 are formed by simultaneously press-molding the outer surface side and the inner surface side of the tank body 12. On the outer peripheral side of the pushing portion 23 and the protruding portion 24 of the heater mounting portion 17, inclined portions 23a, 24a connecting the pushing portion 23 and the protruding portion 24 to the outer surface of the tank body 12 are provided.
Are formed respectively.

The direction deviated by 45 ° between the adjacent pushing portion 23 and the protruding portion 24, that is, the axial direction and the circumferential direction of the tank body 12 (the section taken along the line CC in FIG. (C sectional view is shown in Fig. 2 (c)).
The boundary portion 25 is not pushed or protruded by press molding, and the peripheral surface shape of the tank body 12 is left as it is.

The outer surface of the heater mounting portion 17 has a push-in portion.
A plurality of bolts 26 are fixed by stud welding at equal intervals along the annular heater mounting portion 17 at a position avoiding a boundary portion 25 between the 23 and the protruding portion 24. In this embodiment, eight bolts 26 are used, and 45 bolts are provided along the annular heater mounting portion 17.
゜ It is arranged at intervals. That is, the positions of all the bolts 26 are shifted by 22.5 ° with respect to the conventional structure shown in FIG. Further, a flange 27 having a diameter larger than the diameter of the bolt 26 is formed at an end of the bolt 26 stud-welded to the heater mounting portion 17.

The heater support 19 has a flat disk shape, and has a plurality of mounting holes 19a through which the bolts 26 are inserted corresponding to the positions of the bolts 26. Each mounting hole 19a is formed in each bolt 26. Is inserted, and a nut 28 is screwed into each bolt 26 and fastened to fix it to the heater mounting portion 17. Also,
When the packing 20 is not attached to the heater support 19,
When the heater support 19 is attached to the tank body 12, the tank body 12 and the heater support 19 are pressed into contact with each other to form a liquid. It is configured to keep it dense.

At the time of assembling the electric water heater, the heater 18 is inserted into the hot water tank 11 through the heater insertion hole 16 while the packing 20 is fitted in the concave portion 22 of the peripheral portion of the heater insertion hole 16. The mounting holes 19a of the support 19 are passed through the bolts 26, the nuts 28 are screwed into the bolts 26 and tightened, and the heater support 19 is fixed to the heater mounting portion 17 with the heater insertion hole 16 closed.

When the electric water heater is used, the heater support 19 for closing the heater insertion hole 16 is provided with the hot water tank 11.
The internal water pressure is applied, and this water pressure is received by the heater mounting portion 17 via a plurality of bolts 26. At this time, hot water tank 11
In the inside, pressure fluctuations are repeated due to a change in water pressure due to opening and closing of the faucet by a first stop type, a change in pressure according to water temperature such as expansion due to boiling, etc., and a force due to the pressure fluctuation in this hot water tank 11 But the heater mounting part via each bolt 26
Join 17 repeatedly.

At this time, the plurality of bolts 26 are weaker in strength than the pushing portion 23 and the projecting portion 24 and have
25 is provided at a portion where the strength is enhanced by forming the pushing portion 23 and the protruding portion 24, so that the pushing portion 23 and the protruding portion 24 having the enhanced strength are used for the hot water tank. The force caused by the pressure fluctuation in the hot water tank 11 is not directly and repeatedly applied to the boundary portion 25, which is a weak portion and a sag portion, due to the force accompanying the pressure fluctuation in the inside 11 through the bolt 26, Deterioration due to metal fatigue at 25 can be reduced, and water leakage from boundary portion 25 can be prevented.

Further, since the bolts 26 are provided at equal intervals along the heater mounting portion 17, the bolts 26 can be
In addition to the provision of the heater 26, the heater mounting portion 17 and the heater support 19 are evenly mounted, so that water leakage from between the heater mounting portion 17 and the heater support 19 can be prevented.

Next, FIG. 4 shows a second embodiment. FIG. 4 is a perspective view of a portion of the bolt 26, in which a plurality of bolts 26 are welded to an annular ring 31, and this ring 31 is attached to a heater mounting portion.
It is fixed by welding to the outer surface of 17 and can reinforce the heater mounting portion 17 including the boundary portion 25, and even if the welding portion of the bolt 26, that is, the ring 31, deteriorates and cracks occur, water leakage may occur In addition, the bolt 26 can be arranged at any position.

Next, FIG. 5 shows a third embodiment. FIG. 5 is an exploded perspective view of a portion of the bolt 26, which uses an annular ring 34 having a plurality of insertion holes 33 through which the bolts 26 of the heater mounting portion 17 are inserted. With each insertion hole 33 inserted through each welded bolt 26,
By fixing the ring 34 to the outer surface of the heater mounting portion 17 by welding, the heater mounting portion 17 including the boundary portion 25 can be reinforced.

Next, FIG. 6 shows a fourth embodiment. FIG. 6 is a front view of a portion of the heater insertion hole 16 of the hot water tank 11, in which a reinforcing beat 35 is formed in an annular shape around the entire heater mounting portion 17 of the tank body 12 by press molding. The heater mounting portion 17 can be reinforced.

The reinforcing beat 35 may be formed intermittently or at a position corresponding to the boundary portion 25 in addition to being formed annularly over the entire periphery of the heater mounting portion 17. The heater mounting portion 17 including the portion 25 can be reinforced.

Next, FIG. 7 shows a fifth embodiment. FIG. 7A is a cross-sectional view of a concave welding seat 36, and FIG. 7B is a cross-sectional view of a convex welding seat 37, at a position where the bolt 26 on the outer surface of the heater mounting portion 17 is welded. A concave welding seat 36 or a convex welding seat 37 is formed, and the heater mounting portion 17 is reinforced by forming the concave welding seat 36 or the convex welding seat 37. it can.

When the bolt 26 is stud-welded, the welding projections 27a protruding from the flange 27 of the bolt 26 are brought into contact with the welding seats 36 and 37, so that the bolt 26 and the welding seat
Large welding current supplied between 36 and 37
The welding projection 27a melts to generate spatter, and the spatter is generated through the spatter.
27 and the welding seats 36 and 37 are welded in close contact.

It is necessary that gas generated at the time of the stat welding should be satisfactorily released from between the flange 27 of the bolt 26 and the welding seats 36 and 37. Therefore, the concave welding seat 36 is formed.
In this case, it is preferable to make the width of the welding seat 36 wider than the bolt 26.

Next, FIG. 8 shows a sixth embodiment. FIG. 8 is a front view of a portion of the bolt 26, in which a reinforcing beat 38 is provided at a position near the bolt 26 of the heater mounting portion 17, so that the welding vicinity of the bolt 26 of the heater mounting portion 17 can be reinforced.

The first to sixth embodiments can be combined as appropriate. The synergistic effect of this combination can further reinforce the heater mounting portion 17 and reliably prevent water leakage.

[0043]

According to the electric water heater according to the first aspect of the present invention, the plurality of bolts are positioned at a position avoiding a boundary portion where the strength is weaker than that of the pushing portion and the projecting portion, that is, the pushing portion and the projecting portion are connected. By providing at the position where the strength is strengthened by forming, the force due to the pressure fluctuation in the hot water tank is not directly and repeatedly applied to the boundary portion via the bolt, it is possible to reduce the deterioration of the boundary portion, Water leakage from the boundary can be prevented.

According to the electric water heater according to the second aspect, in addition to the effect of the electric water heater according to the first aspect, by providing the bolts at equal intervals along the heater mounting portion, the boundary portion can be avoided. After the bolts are provided, the heater mounting portion and the heater support are evenly mounted to prevent water leakage from between the heater mounting portion and the heater support.

According to the electric water heater according to the third aspect, in addition to the effects of the electric water heater according to the first or second aspect, the welding seat for welding a bolt to the outer surface of the heater mounting portion has a concave shape and a convex shape. In this case, the heater mounting portion can be reinforced.

According to the electric water heater according to the fourth aspect, in addition to the effect of the electric water heater according to the first or second aspect, the reinforcing beat is provided at a position near the bolt of the heater mounting portion, so that the heater can be mounted. The part can be reinforced.

According to the electric water heater according to the fifth aspect, in addition to the effect of the electric water heater according to the first or second aspect, the heater mounting is performed in a state where the respective insertion holes are inserted into the bolts of the heater mounting portion. By fixing the ring to the outer surface of the section, the heater mounting section can be reinforced.

According to the electric water heater according to the sixth aspect, in addition to the effect of the electric water heater according to the first or second aspect, the ring provided with the bolt is fixed to the outer surface of the heater mounting portion, so that the heater can be mounted. The part can be reinforced.

According to the electric water heater according to the seventh aspect, in addition to the effect of the electric water heater according to the first or second aspect, by providing a reinforcing beat around the heater mounting portion of the tank body, the heater mounting is achieved. The part can be reinforced.

[Brief description of the drawings]

FIG. 1 is a front view of a portion of a heater insertion hole of a hot water tank, showing a first embodiment of an electric water heater of the present invention.

2A is a cross-sectional view taken along line AA of FIG. 1, FIG. 2B is a cross-sectional view taken along line BB of FIG. 1, and FIG. 2C is a cross-sectional view taken along line CC of FIG.

FIG. 3 is a schematic sectional view of the electric water heater.

FIG. 4 is a perspective view of a bolt according to a second embodiment.

FIG. 5 is an exploded perspective view of a bolt part according to a third embodiment.

FIG. 6 is a front view of a heater insertion hole portion of a hot water tank according to a fourth embodiment.

7A and 7B show a fifth embodiment, in which FIG. 7A is a sectional view of a concave welding seat, and FIG. 7B is a sectional view of a convex welding seat.

FIG. 8 is a front view of a bolt according to a sixth embodiment.

FIG. 9 is a front view of a heater insertion hole of a conventional hot water tank.

[Explanation of symbols]

 11 Hot water tank 12 Tank body 16 Heater insertion hole 17 Heater mounting part 18 Heater 19 Heater support 23 Push-in part 24 Projection 25 Boundary part 26 Bolt 31 Ring 33 Insertion hole 34 Ring 35 Reinforcement beat 36, 37 Weld seat 38 Reinforcement beat

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shigeaki Tsukada 180 Furuichi-cho, Maebashi-shi, Gunma Toshiba Equipment Co., Ltd. (72) Inventor Masahiko 180 Furuichi-cho, Maebashi-shi, Gunma F-term in Toshiba Equipment Co., Ltd. (Reference) 3L036 AB08 AB09 AC18

Claims (7)

[Claims] 1. A hot water tank having a cylindrical tank body, a heater insertion hole provided in the tank body, and a pushing portion provided on a peripheral portion of the heater insertion hole and pushed into an inner surface of the tank body. A heater mounting portion having a protrusion protruding from the outer surface side of the tank body, the heater mounting portion being made flat by the pressing portion and the protruding portion, and the pressing portion and the protruding portion being formed on the outer surface of the heater mounting portion. A plurality of bolts provided at positions avoiding a boundary portion between the heater and the heater, the heater being inserted into the tank body through the heater insertion hole, the heater being attached to the heater attachment portion via bolts, An electric water heater comprising: a heater support for closing an insertion hole. 2. The electric water heater according to claim 1, wherein the bolts are provided at equal intervals along the heater mounting portion. 3. The heater mounting portion according to claim 1, wherein a welding seat portion is provided on the outer surface of the heater mounting portion in either a concave shape or a convex shape, and the bolt is welded to the welding seat portion of the heater mounting portion. 3. The electric water heater according to 1 or 2. 4. The electric water heater according to claim 1, wherein a reinforcing beat is provided at a position near the bolt of the heater mounting portion. 5. A ring having a plurality of insertion holes through which bolts of the heater mounting portion are inserted, and a ring fixed to an outer surface of the heater mounting portion in a state where the respective insertion holes are inserted through the bolts. The electric water heater according to claim 1 or 2, wherein: 6. The electric water heater according to claim 1, further comprising a ring fixed to an outer surface of the heater mounting portion, wherein each bolt of the heater mounting portion is provided on the ring. 7. The electric water heater according to claim 1, wherein a reinforcing beat is provided around a heater mounting portion of the tank body.