Electrical device

Abstract

The utility model provides an electrical device which can maintain a grounding state even if a component connected with a grounding terminal is loosened. An electrical device (10) is provided with: a conductive metal member (23) in which a through-hole (23d) is formed; a ground terminal (36) disposed on the lower side of the metal member (23); a holding member (37) that has a shaft portion (37a) that passes through the ground terminal (36) and the through-hole (23d) of the metal member (23), and a holding portion (37b) that holds the ground terminal (36); conductive parts (37-39) that conduct electricity between the metal member (23) and the ground terminal (36); and a support part (40) that supports the lower side of the holding part (37b).

Description

Technical Field

[0001] The present utility model relates to an electrical device. Background Art

[0002] Electrical devices such as heating plates are composed of a combination of resin parts, metal parts, and electrical parts. In such electrical devices, a grounding structure is required as a safety measure.

[0003] Patent Document 1 discloses a grounding structure for a lighting fixture. This grounding structure is as follows: A bolt that penetrates from the upper side of an appliance body, which is a metal part, is threadedly coupled with a first nut from the lower side of the appliance body. A grounding terminal to which a grounding wire is connected is disposed, and a second nut is threadedly coupled from the lower side. The bolt and the two nuts are made of metal.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Utility Model Laid-Open No. 51-150684 Summary of the Utility Model

[0007] Technical Problem to be Solved by the Utility Model

[0008] Loosening of the bolt due to vibration or the like applied to the electrical device during use is inevitable. Also, if the grounding terminal becomes detached due to loosening of the bolt, the grounding is disconnected. In the grounding structure of Patent Document 1, no consideration is given to grounding disconnection caused by loosening of the bolt.

[0009] An object of the present utility model is to provide an electrical device that can maintain a grounded state even if a member connecting the grounding terminal becomes loose.

[0010] Technical Solution for Solving the Technical Problem

[0011] One aspect of the present utility model provides an electrical device including: a conductive metal part that extends along a first direction and a second direction intersecting the first direction, and has a through-hole penetrating in a third direction intersecting both the first direction and the second direction; a grounding terminal that is connected to a grounding wire for grounding the metal part and is disposed on a side of the metal part in the third direction; a holding member having a shaft portion and a holding portion, the shaft portion penetrating through the through-hole of the grounding terminal and the metal part, and the holding portion being provided at an end of the shaft portion on a side in the third direction to hold the grounding terminal; a conductive portion that electrically conducts the metal part and the grounding terminal; and a support portion that can support the holding portion to prevent the holding member from falling off.

[0012] The ground terminal is disposed on one side of a conductive metal component via a holding member, and electrical conductivity with the metal component is ensured through a conductive portion. Moreover, a support portion capable of supporting the holding portion is provided. Therefore, even if the shaft portion of the holding member passing through the metal component becomes loose, the holding member can be prevented from falling off by the support portion. In addition, since electrical conductivity between the metal component and the ground terminal is ensured through the conductive portion, grounding is not interrupted. Therefore, the grounded state of the metal component can be reliably maintained.

[0013] The above-mentioned holding member is constituted by a metal bolt, the metal bolt having a bolt shaft as the above-mentioned shaft portion and a head as the above-mentioned holding portion, the conductive portion being constituted by the bolt and a metal first nut, the metal first nut being threadedly coupled to the bolt shaft in such a manner as to contact the surface on the other side in the above-mentioned third direction in the metal component.

[0014] According to this structure, the first nut is in surface contact with the metal component and the bolt shaft, and the head of the bolt is in surface contact with the ground terminal. Thereby, the electrical conductive area between the metal component and the ground terminal can be ensured, and thus the metal component can be reliably grounded under normal conditions.

[0015] The above-mentioned holding member is constituted by a bolt, the bolt having a bolt shaft as the above-mentioned shaft portion and a head as the above-mentioned holding portion, the conductive portion being constituted by a metal second nut, the metal second nut being threadedly coupled to the bolt shaft in such a manner as to contact the metal component and the ground terminal respectively.

[0016] According to this structure, the second nut is in surface contact with the metal component, the ground terminal, and the bolt shaft respectively. Thereby, the electrical conductive area between the metal component and the ground terminal can be ensured, and thus the metal component can be reliably grounded under normal conditions.

[0017] The above-mentioned holding member is constituted by a metal bolt, the metal bolt having a bolt shaft as the above-mentioned shaft portion and a head as the above-mentioned holding portion, the conductive portion being constituted by the bolt, a metal first nut, and a metal second nut, the metal first nut being threadedly coupled to the bolt shaft in such a manner as to contact the surface on the other side in the above-mentioned third direction in the metal component, the metal second nut being threadedly coupled to the bolt shaft in such a manner as to contact the metal component and the ground terminal respectively.

[0018] According to this structure, the first nut is in surface contact with the metal component and the bolt shaft, the head of the bolt is in surface contact with the ground terminal, and the second nut is in surface contact with the metal component, the ground terminal, and the bolt shaft respectively. Thereby, the electrical conductive area between the metal component and the ground terminal can be ensured, and thus the metal component can be reliably grounded under normal conditions.

[0019] The above-mentioned support portion has a restricting portion that restricts the movement of the above-mentioned holding member in the above-mentioned first direction and the above-mentioned second direction. The above-mentioned support portion is provided on the wall of the resin member, and the wall of the resin member is disposed on the side closer to the above-mentioned third direction with respect to the above-mentioned metal member.

[0020] According to this structure, when the holding member is assembled and disposed on the support portion formed on the wall of the resin member, it is positioned by the restricting portion. Therefore, it is possible to pass the holding member, which is difficult to visually observe, through the through-hole, and easily dispose the metal member above the resin member. Therefore, the assembling workability of the electric device can be improved.

[0021] The above-mentioned support portion has a restricting portion that restricts the rotation of the above-mentioned holding member about the axis of the above-mentioned shaft portion. The above-mentioned support portion is provided on the wall of the resin member, and the wall of the resin member is disposed on the side closer to the above-mentioned third direction with respect to the above-mentioned metal member.

[0022] According to this structure, when the first nut is threadedly coupled to the shaft portion that penetrates the through-hole, the holding member can be prevented from rotating. Therefore, the assembling workability of the electric device can be improved.

[0023] The above-mentioned support portion has a restricting portion that restricts the movement of the above-mentioned holding member in the above-mentioned first direction and the above-mentioned second direction and the rotation of the above-mentioned holding member about the axis of the above-mentioned shaft portion. The above-mentioned support portion is provided on the wall of the resin member, and the wall of the resin member is disposed on the side closer to the above-mentioned third direction with respect to the above-mentioned metal member.

[0024] According to this structure, the holding member can be positioned by the restricting portion in a state where it is disposed on the support portion formed on the wall of the resin member during assembly. Therefore, the holding member, which is difficult to visually observe, can be passed through the through-hole, and the metal member can be easily disposed above the resin member. In addition, when the first nut is threadedly coupled to the shaft portion that penetrates the through-hole, the holding member can be prevented from rotating. Therefore, the assembling workability of the electric device can be improved.

[0025] The above-mentioned electric device includes: a heat insulating plate on which a heater is disposed on the upper side; a cooking plate that is detachably disposed on the upper side of the above-mentioned heat insulating plate; and a resin substrate case that houses a control substrate for heating the above-mentioned cooking plate by the above-mentioned heater and is disposed on the lower side of the above-mentioned heat insulating plate. The above-mentioned support portion is provided on the bottom wall of the above-mentioned substrate case, and the above-mentioned metal member is disposed between the above-mentioned heat insulating plate and the above-mentioned substrate case and is mounted on the upper end opening of the above-mentioned substrate case.

[0026] In an electric cooker (such as a hot plate) which is configured as such, when the liquid such as the soup in the cooking plate or the moisture from the cooked food overflows due to the heating of the heater, even if such an overflow occurs, the control substrate can be prevented from being wetted by the liquid by the metal member. Therefore, the usability and reliability of the hot plate can be improved.

[0027] Effect of the utility model

[0028] In the present utility model, even if the member connecting the grounding terminal becomes loose, the grounding state can be maintained. Description of the drawings

[0029] Figure 1 is an exploded perspective view of the hot plate according to the first embodiment of the present utility model.

[0030] Figure 2 is taken along Figure 1 a partial cross-sectional view cut along the line II-II of.

[0031] Figure 3 is an exploded perspective view of a part of Figure 1 magnified.

[0032] Figure 4 is a perspective view of a part of Figure 3 including part IV magnified.

[0033] Figure 5 is a cross-sectional view showing the state where the upper nut has come off and is the same as Figure 2 that of.

[0034] Figure 6 is a cross-sectional view of the hot plate according to the second embodiment and is the same as Figure 2 that of. Detailed implementation mode

[0035] Hereinafter, embodiments of the present utility model will be described with reference to the drawings.

[0036] (First embodiment)

[0037] Referring to Figure 1 , the hot plate 10 of the electric device according to the first embodiment of the present utility model heats the cooking plate 12 by the heater 18, thereby heating and cooking the cooked food on the cooking plate 12.

[0038] The X direction in the attached drawings corresponds to the length direction of the heating plate 10, which is equivalent to the first direction in the present invention. The Y direction corresponds to the width direction of the heating plate 10, which is equivalent to the second direction in the present invention. The Z direction corresponds to the height direction (up and down direction) of the heating plate 10, which is equivalent to the third direction in the present invention. The direction indicated by the arrow in the Z direction is the upper side, which is equivalent to the other side of the third direction in the present invention. The direction opposite to the arrow in the Z direction is the lower side, which is equivalent to one side of the third direction in the present invention. However, the first to third directions in the present invention can be changed as needed.

[0039] The heating plate 10 includes a cooking plate 12, a main body housing 14, a heat insulation plate 16, a heater 18, and a control unit 20.

[0040] The cooking plate 12 is in the shape of a tray with a given depth and is formed of a material with high thermal conductivity. The cooking plate 12 in the present embodiment is rectangular when viewed from above. However, the depth and shape of the cooking plate 12 can be changed as needed.

[0041] The main body housing 14 is made of resin (resin component) with insulation properties and is rectangular when viewed from above, being one size larger than the cooking plate 12. However, the shape of the main body housing 14 can also be changed as needed. The control unit 20 is fixedly installed at the bottom of the main body housing 14 by threading. The heat insulation plate 16 is fixedly installed on the upper side of the control unit 20 within the main body housing 14 by threading.

[0042] The heat insulation plate 16 is in the shape of a tray with a given depth and is a metal component that suppresses the radiant heat of the heater 18 from being applied to the control unit 20. On the upper side of the heat insulation plate 16, the heater 18 is fixedly installed via a bracket by threading. The cooking plate 12 is detachably arranged on the upper side of the heater 18 in the heat insulation plate 16.

[0043] Refer to Figure 2 and Figure 3 , the control unit 20 includes a housing 21 composed of a substrate housing 22 and a cover 23. A power plug 24 and an operation unit 29 are installed on the housing 21, and the control substrate 30 is accommodated, thereby constituting the control unit 20. A ground connection portion (grounding structure) 35 is provided in the control unit 20 as a safety measure.

[0044] Refer to Figure 3 and Figure 4 , the power plug 24 includes a pair of power supply terminals 25 and a ground terminal 27. The pair of power supply terminals 25 are connected to the control substrate 30 via a lead wire 26. The ground terminal 27 is connected to the ground terminal 36 of the ground connection portion 35 via a ground wire 28. The power plug 24 passes through Figure 1It is exposed to the outside through the through-hole 14a of the main body housing 14 shown. The power supply terminal 25 and the ground terminal 27 use flat terminals. However, the power supply terminal 25 and the ground terminal 27 may have a structure that can connect the ground wire 28 to the power plug 24 and can be changed as needed. In addition, the ground wire 28 can be directly connected to the power plug 24 without using the power supply terminal 25 and the ground terminal 27.

[0045] The operation unit 29 is provided to adjust the power supply amount to the Figure 1 heater 18 shown. The operation unit 29 has a rotary knob and is connected to the control board 30 through a lead wire (not shown). The operation unit 29 passes through the Figure 1 through-hole 14b of the main body housing 14 shown and is exposed to the outside.

[0046] In addition to being connected to the power plug 24 and the operation unit 29, the control board 30 is also connected to the Figure 1 heater 18 shown. By inserting a power cord (not shown) into the power plug 24 and operating the operation unit 29, the control unit provided in the control board 30 controls the Figure 1 heater 18 shown to cook the food on the cooking plate 12.

[0047] Refer to Figure 2 and Figure 4 , the ground connection part 35 is provided to conductively connect the cover 23 to the ground terminal 27 of the power plug 24. The ground connection part 35 is composed of a through-hole 23d formed in the cover 23, a ground terminal 36, a bolt 37, two nuts 38, 39, and a support part 40 formed in the board housing 22.

[0048] Refer to Figure 3 , the board housing 22 is made of insulating resin (resin component) and is arranged on the Figure 1 lower side of the heat insulation plate 16 shown. The board housing 22 has a bottom wall 22a extending along the XY plane as a whole and an outer peripheral wall 22b protruding upward from the outer periphery of the bottom wall 22a. The upper end of the outer peripheral wall 22b is an open opening 21c. In the board housing 22, a plurality of bosses are formed for screwing and fixing components such as the power plug 24, the operation unit 29, and the control board 30.

[0049] At one end in the length direction of the board housing 22 (on the Figure 3 right side in Figure 3 ), a plug mounting part 22d is provided. On one side in the width direction of the board housing 22 (on the Figure 3On the inner side (the middle is the inner side), a substrate arrangement portion 22f is provided. Near the plug mounting portion 22d in the bottom wall 22a of the substrate housing 22, a support portion 40 for the ground connection portion 35 is provided. The support portion 40 will be described in detail later.

[0050] The cover 23 is a conductive metal component. The cover 23 is integrally in a plate shape extending horizontally along the XY plane and is disposed Figure 1 between the heat insulation plate 16 shown and the substrate housing 22, and is mounted to the opening 21c of the substrate housing 22 by screw fixation. That is, the cover 23 is disposed at an interval above the bottom wall 22a of the substrate housing 22 and is fixed in a state of covering the opening 21c of the substrate housing 22.

[0051] In the cover 23, a plurality of through holes 23a for screw fixation and a through hole 23b for inserting a lead wire (not shown) connecting the control substrate 30 and Figure 1 the heater 18 shown are provided. The through holes 23a and the through hole 23b are respectively formed on the upper surfaces of a plurality of raised portions 23c that bulge upward from the cover 23. Thereby, it is possible to prevent liquid from entering the substrate housing 22 through the through holes 23a and the through hole 23b.

[0052] In the cover 23, a through hole 23d penetrating in the vertical direction is also provided so as to be directly above the support portion 40. No raised portion is provided in the portion of the cover 23 where the through hole 23d is formed. However, a raised portion may also be provided in the portion of the cover 23 where the through hole 23d is formed.

[0053] Refer to Figure 2 and Figure 4 , the ground terminal 36 is disposed on the lower side that can move downward relative to the cover 23 by its own weight and is used for conductively connecting to the cover 23 and grounding. The ground terminal 36 is composed of a circular terminal, and this circular terminal has a riveting portion 36a for connecting the ground wire 28 and an annular connecting portion 36b connected to one end of the riveting portion 36a. The connecting portion 36b has a through hole with substantially the same diameter as the through hole 23d.

[0054] The bolt 37 and two nuts 38, 39 are used to mount the ground terminal 36 to the cover 23. The bolt 37 and the two nuts 38, 39 are both made of metal and constitute a conductive portion for making the cover 23 and the ground terminal 36 conductive.

[0055] The bolt 37 has a bolt shaft 37a and a head 37b. The bolt shaft 37a is a shaft portion having a spiral groove on its outer peripheral portion. The bolt shaft 37a has as large a diameter as possible within the range capable of passing through the through-hole 23d of the cover 23 and the connecting portion 36b of the ground terminal 36, and is installed on the cover 23 via the upper nut 38. The head 37b is provided at the lower end of the bolt shaft 37a and functions as a holding portion for holding the connecting portion 36b of the ground terminal 36. When viewed from the direction in which the axis A of the bolt shaft 37a extends, the head 37b is a hexagonal shape larger than the through-hole 23d. However, the head 37b of the bolt 37 may also be a non-circular shape other than a hexagon.

[0056] Both of the two nuts 38, 39 have bolt holes 38a, 39a capable of being threadedly engaged with the bolt shaft 37a. When viewed from the direction in which the axis A of the bolt shaft 37a extends, the nuts 38, 39 are hexagonal shapes having a diameter larger than the diameter of the through-hole 23d. However, the nuts 38, 39 may also be shapes other than a hexagon.

[0057] One of the two nuts 38, 39 is disposed on the upper side of the cover 23 and is in surface contact with the upper surface of the cover 23 in the assembled state. The other of the two nuts 38, 39 is disposed on the lower side of the cover 23 and is in surface contact with the lower surface of the cover 23 and the upper surface of the connecting portion 36b of the ground terminal 36, respectively, in the assembled state. In the following description, the one disposed on the upper side of the cover 23 may sometimes be referred to as the upper nut (first nut) 38, and the one disposed on the lower side of the cover 23 may sometimes be referred to as the lower nut (second nut) 39.

[0058] The support portion 40 supports the lower side of the head 37b of the bolt 37 and prevents the bolt 37 from falling off the cover 23 together with the ground terminal 36. More specifically, when the upper nut 38 becomes loose with respect to the bolt shaft 37a and the bolt 37 moves downward together with the ground terminal 36, the support portion 40 supports the head 37b (lower end) of the bolt 37.

[0059] The support portion 40 is disposed adjacent to the power plug 24 in the bottom wall 22a of the substrate housing 22. The support portion 40 is formed by a convex portion protruding upward and has an outer shape larger than the outer shape of the head 37b when viewed from the direction in which the axis A of the bolt shaft 37a extends. The height H of the support portion 40 is set such that the distances D1, D2 from the support portion 40 to the cover 23 satisfy the following mathematical formula.

[0060] [Mathematical formula 1]

[0061] S < D1

[0062] D2 < L

[0063] D1: The distance from the support portion to the lower surface of the cover

[0064] D2: Distance from the support part to the upper surface of the cover

[0065] S: Height dimension of the connection part

[0066] L: Total length of the bolt

[0067] The height H of the support part 40 refers to the dimension from the upper surface of the bottom wall 22a to the upper surface of the support part 40. The distance D1 from the support part 40 to the lower surface of the cover 23 refers to the dimension from the upper surface of the support part 40 to the lower surface of the portion in the assembled cover 23 where the through hole 23d is formed. The distance D2 from the support part 40 to the upper surface of the cover 23 refers to the dimension from the upper surface of the support part 40 to the upper surface of the portion in the assembled cover 23 where the through hole 23d is formed. The height dimension S of the connection part refers to the total dimension of the height direction dimension of the head 37b of the bolt 37, the thickness in the height direction of the connection part 36b of the ground terminal 36, and the height direction dimension of the lower nut 39. The total length L of the bolt 37 refers to the dimension from the lower end face of the head 37b to the upper end face of the bolt shaft 37a.

[0068] As in the above mathematical formula, the height H of the support part 40 is set such that the height dimension S of the connection part is smaller than the distance D1 from the support part 40 to the lower surface of the cover 23. Thus, the connection part including the ground terminal 36 can be reliably housed within the housing 21.

[0069] On the other hand, the height H of the support part 40 is set such that the total length L of the bolt 37 is longer than the distance D2 from the support part 40 to the upper surface of the cover 23. In this way, when assembling the control unit 20, if the cover 23 is arranged on the substrate housing 22 with the bolt 37 placed on the support part 40, the bolt shaft 37a protrudes upward from the through hole 23d. Thus, the assemblability of the control unit 20 can be improved. In addition, as Figure 5 shown, even if the upper nut 38 comes off from the bolt 37 and the state becomes such that the head 37b is placed on the support part 40, the bolt shaft 37a is also in a state of being located within the through hole 23d. Thus, by the contact of a part of the bolt shaft 37a with the hole wall of the through hole 23d, the conductivity between the bolt 37 and the cover 23 required for grounding can be ensured.

[0070] A frame portion 40a protruding upward is provided on the support portion 40. When viewed from the direction in which the axis A of the bolt shaft 37a extends, the frame portion 40a is substantially C-shaped and functions as a restricting portion for restricting the lateral movement of the bolt 37. The inner surface 40b of the frame portion 40a is hexagonal corresponding to the head 37b of the bolt 37 and functions as a restricting portion for restricting the rotation of the bolt 37 about the axis A of the bolt shaft 37a. The height of the frame portion 40a is a dimension substantially the same as the thickness of the head 37b in the direction in which the axis A of the bolt shaft 37a in the bolt 37 extends. However, the frame portion 40a including the inner surface 40b can be changed as needed as long as it is a structure capable of restricting the lateral movement of the bolt 37 and the rotation of the bolt 37 about the axis A.

[0071] A positioning portion 41 for positioning the ground terminal 36 is also provided on the bottom wall 22a of the substrate housing 22. The positioning portion 41 is disposed adjacent to the support portion 40 so as to be located on the power plug 24 side. The positioning portion 41 protrudes from the bottom wall 22a in a concave shape and positions both sides of the riveting portion 36a of the ground terminal 36. Thereby, the wiring direction of the ground wire 28 connected to the ground terminal 36 can be determined, and thus it is possible to prevent the ground wire 28 from becoming unnecessarily long and from being subjected to an accidental load.

[0072] Next, an example of the assembly sequence of the control unit 20 will be described.

[0073] First, after all the constituent parts including the power plug 24, the operation unit 29, and the control substrate 30 are arranged on the substrate housing 22, the head 37b is housed in the frame portion 40a and the bolt 37 is arranged on the support portion 40. Next, the connecting portion 36b of the ground terminal 36 to which the ground wire 28 is connected is passed through the bolt shaft 37a, and the riveting portion 36a is arranged in the positioning portion 41 for positioning.

[0074] Next, the lower nut 39 is threadedly engaged with the bolt shaft 37a for fastening, and the connecting portion 36b of the ground terminal 36 is sandwiched between the lower nut 39 and the head 37b. At this time, since the riveting portion 36a is positioned in the positioning portion 41, it is possible to prevent the ground terminal 36 from rotating together due to the fastening of the lower nut 39. Therefore, the ground wire 28 connected to the ground terminal 36 can be reliably wired in a given direction.

[0075] Next, after connecting the ground terminal 27 connected to the front end of the ground wire 28 to the power plug 24, the cover 23 is arranged in the opening 21c of the substrate housing 22 and fixed by screwing. At this time, the lateral movement of the bolt 37 is restricted by the frame portion 40a. Moreover, by setting the overall length L of the bolt 37 relative to the distance D2 from the support portion 40 to the upper surface of the cover 23, if the bolt shaft 37a does not penetrate the through-hole 23d, the cover 23 cannot be arranged at the correct position on the substrate housing 22. Therefore, even if the bolt 37 is located below the cover 23 and is in a state where it is difficult to visually observe, as Figure 5 shown, the bolt shaft 37a can penetrate the through-hole 23d, and it is easy to arrange the cover 23 at the correct position on the substrate housing 22.

[0076] Finally, a nut 38 is threadedly engaged and tightened on the bolt shaft 37a protruding from the cover 23. At this time, the rotation of the bolt 37 about the axis A is restricted by the frame portion 40a. Therefore, by tightening the upper nut 38, the bolt 37 moves linearly upward together with the lower nut 39 and the ground terminal 36, as Figure 2 shown, and an assembled state in which the cover 23 is sandwiched between the upper nut 38 and the lower nut 39 can be achieved.

[0077] In this state, the upper nut 38 is in surface contact with the cover 23 and the bolt shaft 37a. In addition, the lower nut 39 is in surface contact with the cover 23, the connecting portion 36b of the ground terminal 36, and the bolt shaft 37a. Moreover, the head portion 37b of the bolt 37 is also in surface contact with the ground terminal 36. Thereby, the conductive area between the cover 23 and the ground terminal 36 can be sufficiently ensured, and thus the cover 23 can be reliably grounded via the ground wire 28 and the power plug 24.

[0078] When the control unit 20 is used for Figure 1 the heating plate 10 shown, in the case where the upper nut 38 becomes loose due to use, or in the case where the upper nut 38 falls off as Figure 5 shown, the bolt 37 moves downward together with the ground terminal 36 and the lower nut 39 and is placed on the support portion 40. In this state, the lower nut 39 is located below the cover 23 at an interval, but the bolt shaft 37a penetrates the through-hole 23d and protrudes upward from the cover 23, and contacts the hole edge of the through-hole 23d. Therefore, the conductivity between the cover 23 and the ground terminal 36 is ensured via the bolt 37. Therefore, the grounded state of the cover 23 can be maintained via the ground wire 28 and the power plug 24.

[0079] Preferably, a structure is adopted in which the bolt shaft 37a reliably contacts the hole edge of the through hole 23d in a state where the upper nut 38 is removed from the bolt shaft 37a. For example, it is preferable to set the arrangement of the frame portion 40a and the through hole 23d such that the axis of the through hole 23d is radially spaced apart from the axis A of the bolt 37 having the head 37b disposed in the frame portion 40a. However, the structure for bringing the bolt shaft 37a into contact with the hole edge of the through hole 23d can also be achieved by assembly tolerances or manufacturing tolerances.

[0080] The heating plate 10 configured in this way has the following characteristics.

[0081] The ground terminal 36 is disposed below the conductive cover 23 via the bolt 37, and the conductivity with the cover 23 is ensured by the bolt 37 and the nuts 38 and 39 that constitute the conductive portion. Moreover, a support portion 40 that supports the head 37b of the bolt 37 is provided. Therefore, even if the installation of the bolt shaft 37a to the cover 23 becomes loose, the bolt 37 can be prevented from falling off by the support portion 40. In addition, since the cover 23 and the ground terminal 36 are ensured to be conductive by the bolt 37, the ground connection is not disconnected. Therefore, the grounded state of the cover 23 can be reliably maintained.

[0082] The conductive portion is composed of a metal bolt 37 and a metal upper nut 38 that is threadedly coupled to the bolt shaft 37a so as to contact the upper surface of the cover 23. The upper nut 38 is in surface contact with the cover 23 and the bolt shaft 37a, and the head 37b of the bolt 37 is in surface contact with the ground terminal 36. In this way, the conductive area between the cover 23 and the ground terminal 36 can be ensured by the bolt 37 and the upper nut 38, so that the cover 23 can be reliably grounded under normal conditions.

[0083] The conductive portion further includes a metal lower nut 39 that is threadedly coupled to the bolt shaft 37a so as to contact the cover 23 and the ground terminal 36, respectively. The lower nut 39 is in surface contact with the cover 23, the ground terminal 36, and the bolt shaft 37a, respectively. Thereby, the conductive area between the cover 23 and the ground terminal 36 can be ensured, so that the cover 23 can be reliably grounded under normal conditions.

[0084] The support portion 40 has a frame portion 40a that restricts the lateral movement of the bolt 37. Thereby, the bolt 37 is positioned by the frame portion 40a in a state of being disposed on the support portion 40 of the bottom wall 22a during assembly. Therefore, the bolt 37 that is difficult to visually observe penetrates through the through hole 23d, and the cover 23 can be easily disposed above the bottom wall 22a. Therefore, the assembling operability of the heating plate 10 can be improved.

[0085] The support portion 40 has a frame portion 40a that restricts the rotation of the bolt 37 about the axis A of the bolt axis 37a. Thus, when the upper nut 38 is threadedly engaged with the bolt axis 37a passing through the through-hole 23d, the bolt 37 can be stopped from rotating. Therefore, the assembling operability of the heating plate 10 can be improved.

[0086] When the cover 23 is mounted on the substrate housing 22 with the ground terminal 36 mounted on the cover 23, it is necessary to ensure the length of the ground wire 28 according to the operation of the cover 23. In contrast, in the present embodiment, with the ground terminal 36 disposed in the support portion 40 provided in the substrate housing 22, the cover 23 is mounted on the substrate housing 22, so that the total length of the ground wire 28 can be shortened and the assembling operability can be improved.

[0087] The electrical device includes a heat insulating plate 16 on which a heater 18 is disposed and a substrate housing 22 disposed on the lower side of the heat insulating plate 16, and is a heating plate 10 that heats a cooking plate 12 using the heater 18. Further, a cover 23 is disposed between the heat insulating plate 16 and the substrate housing 22 and is mounted on the opening 21c of the substrate housing 22. In the heating plate 10, due to the heating of the heater 18, liquids such as soup in the cooking plate 12 or moisture from the cooked food may overflow. However, even if such an overflow occurs, the control substrate 30 can be prevented from being wetted by the liquid by the cover 23. Therefore, the usability and reliability of the heating plate 10 can be improved.

[0088] Hereinafter, other embodiments and various modification examples of the present utility model will be described. However, points not particularly mentioned in these descriptions are the same as those in the first embodiment. In the following drawings, the same reference numerals are assigned to the same elements as those in the first embodiment.

[0089] (Second Embodiment)

[0090] Referring to Figure 6 , the structure of the ground connection portion 35 of the control unit 20 used in the heating plate of the second embodiment is different from that of the first embodiment in the following point: there is no Figure 2 shown upper nut 38, lower nut 39 and the frame portion 40a provided in the support portion 40 of the first embodiment.

[0091] Specifically, in the cover 23, around the through-hole 23d, instead of Figure 2 the shown upper nut 38, a cylindrical portion 45 that protrudes upward by flanging is provided. A bolt groove 45a that can be threadedly engaged with the bolt axis 37a is provided on the inner surface side of the cylindrical portion 45.

[0092] When assembling the control unit 20 of the second embodiment, with the connecting portion 36b of the ground terminal 36 passing through the bolt shaft 37a and held by the head 37b, the bolt 37 is threadedly engaged with the cylindrical portion 45 from the lower side of the cover 23 and tightened. Thus, the connecting portion 36b is clamped between the cover 23 and the head 37b of the bolt 37, ensuring electrical conductivity between the ground terminal 36 and the cover 23. In this state, after connecting the ground terminal 27 to the power plug 24, the cover 23 is threadedly fixed and mounted on the substrate housing 22, thereby completing the assembly.

[0093] In the control unit 20 of the second embodiment configured as described above, when loosening occurs and the bolt 37 moves downward, the lower end of the bolt 37 is supported by the support portion 40, preventing the bolt 37 from falling off. Moreover, electrical conductivity between the cover 23 and the ground terminal 36 can be ensured via the metal bolt 37. Therefore, the grounded state of the cover 23 can be reliably maintained.

[0094] It should be noted that the present utility model is not limited to the structures of the above-described embodiments, and various modifications can be made.

[0095] For example, the ground connection portion 35 of the first embodiment may also be a structure without only Figure 2 the lower nut 39 shown. Additionally, the ground connection portion 35 of the first embodiment may also be a structure that uses Figure 2 the cylindrical portion 45 shown instead of Figure 6 the upper nut 38 shown.

[0096] As long as electrical conductivity between the cover 23 and the ground terminal 36 can be ensured, any one or more of the bolt 37, the upper nut 38, and the lower nut 39 may also be made of an insulating resin product. Additionally, the conductive portion can be modified as needed as long as electrical conductivity between the cover 23 and the ground terminal 36 can be ensured.

[0097] The holding member for holding the ground terminal 36 and mounting it on the cover 23 may also be a fastening member other than the bolt 37, and can be modified as needed as long as it can install and hold the ground terminal 36 on the cover 23.

[0098] The metal component to which the ground terminal 36 is connected may also be the heat insulation plate 16 instead of Figure 1 the cover 23 shown.

[0099] The electrical device using the ground connection portion 35 of the present utility model may also be a device other than the heating plate 10.

[0100] Reference Signs

[0101] 10 Heating Plate (Electrical Device)

[0102] 12 Cooking Plate

[0103] 14 Main housing

[0104] 14a Through-hole

[0105] 14b Through-hole

[0106] 16 Heat insulation plate

[0107] 18 Heater

[0108] 20 Control unit

[0109] 21 Outer shell

[0110] 22 Substrate housing (resin component)

[0111] 22a Bottom wall

[0112] 22b Peripheral wall

[0113] 21c Opening

[0114] 22d Plug mounting part

[0115] 22e Operation unit mounting part

[0116] 22f Substrate arrangement part

[0117] 23 Cover (metal component)

[0118] 23a Through-hole

[0119] 23b Insertion through-hole

[0120] 23c Protrusion

[0121] 23d Through-hole

[0122] 24 Power plug

[0123] 25 Power supply terminal

[0124] 26 Lead wire

[0125] 27 Grounding terminal

[0126] 28 Grounding wire

[0127] 29 Operation unit

[0128] 30 Control substrate

[0129] 35 Grounding connection part

[0130] 36 Grounding terminal

[0131] 36a Riveting part

[0132] 36b Connection part

[0133] 37 Bolt (holding member, conductive part)

[0134] 37a Bolt shaft (shaft part)

[0135] 37b Head (holding part)

[0136] 38 Upper nut (first nut, conductive part)

[0137] 38a Bolt hole

[0138] 39 Lower nut (second nut, conductive part)

[0139] 39a Bolt hole

[0140] 40 Support part

[0141] 40a Frame part (restricting part)

[0142] 40b Inner surface

[0143] 41 Positioning part

[0144] 45 Cylindrical part

[0145] 45a Groove

[0146] Axis of the bolt shaft

[0147] X Length direction (first direction)

[0148] Y Width direction (second direction)

[0149] Z Height direction (third direction).

Claims

1. An electrical device, characterized in that, Comprising: A metallic component having electrical conductivity, which extends along a first direction and a second direction intersecting the first direction, and is formed with a through-hole penetrating in a third direction intersecting both the first direction and the second direction; A ground terminal, which is connected to a ground wire for grounding the metallic component, and is disposed on one side in the third direction with respect to the metallic component; A holding member, which has a shaft portion and a holding portion, the shaft portion penetrating through the through-hole of the ground terminal and the metallic component, and the holding portion being provided at an end portion on one side in the third direction of the shaft portion to hold the ground terminal; A conductive portion, which electrically conducts the metallic component and the ground terminal; and A support portion, which can support the holding portion to prevent the holding member from falling off.

2. The electrical device according to claim 1, wherein The holding member is constituted by a metallic bolt, the metallic bolt having a bolt shaft as the shaft portion and a head as the holding portion, The conductive portion is constituted by the bolt and a metallic first nut, the metallic first nut being threadedly coupled to the bolt shaft in a manner of contacting a surface on the other side in the third direction of the metallic component.

3. The electrical device according to claim 1, wherein The holding member is constituted by a bolt, the bolt having a bolt shaft as the shaft portion and a head as the holding portion, The conductive portion is constituted by a metallic second nut, the metallic second nut being threadedly coupled to the bolt shaft in a manner of respectively contacting the metallic component and the ground terminal.

4. The electrical device according to claim 1, wherein The holding member is constituted by a metallic bolt, the metallic bolt having a bolt shaft as the shaft portion and a head as the holding portion, The conductive portion is constituted by the bolt, a metallic first nut, and a metallic second nut, the metallic first nut being threadedly coupled to the bolt shaft in a manner of contacting a surface on the other side in the third direction of the metallic component, and the metallic second nut being threadedly coupled to the bolt shaft in a manner of respectively contacting the metallic component and the ground terminal.

5. The electrical device according to any one of claims 1 to 4, wherein The support portion has a restricting portion for restricting movement of the holding member in the first direction and the second direction, and the support portion is provided on a wall of a resin component, the wall of the resin component being disposed on one side in the third direction with respect to the metallic component.

6. The electrical device according to any one of claims 1 to 4, wherein The support portion has a restricting portion for restricting rotation of the holding member about the axis of the shaft portion, and the support portion is provided on a wall of a resin component, the wall of the resin component being disposed on one side in the third direction with respect to the metallic component.

7. The electrical device according to any one of claims 1 to 4, wherein The support portion has a restricting portion that restricts the movement of the holding member in the first direction and the second direction and the rotation of the holding member about the axis of the shaft portion. The support portion is provided on the wall of a resin member, and the wall of the resin member is disposed on the side closer to the third direction with respect to the metal member.

8. The electrical device according to any one of claims 1 to 4, characterized in that, The electrical device includes: a heat insulating plate having a heater disposed thereon; a cooking plate detachably disposed above the heat insulating plate; and a resin substrate housing that houses a control substrate for heating the cooking plate by the heater and is disposed below the heat insulating plate, wherein the support portion is provided on the bottom wall of the substrate housing, and the metal member is disposed between the heat insulating plate and the substrate housing and is attached to the upper end opening of the substrate housing.

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