Heat dissipation structure and drive unit

Abstract

To secure dust resistance and waterproofness.SOLUTION: A heat dissipation structure 100 comprises: a housing 3; a heat discharge mechanism 5; and a seal member 6. The housing 3 houses a heat generation body 101. The heat discharge mechanism 5 includes: a heat transfer part 51; and a heat radiation part 52. The heat transfer part 51 is arranged in the housing 3. The heat transfer part 51 is constructed so as to transfer heat of the heat generation body 101. The heat radiation part 52 is arranged to an external part of the housing 3. The seal member 6 seals between the heat discharge mechanism 5 and the housing 3.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heat dissipation structure and a drive unit. [Background technology]

[0002] Generally, an electrical appliance has an electronic board disposed in a housing. A heat generating element such as a semiconductor element is mounted on the electronic board. To cool the heat generating element, for example, Patent Document 1 discloses a heat dissipation structure in which an air intake and an exhaust port are provided in the housing and a cooling fan is provided inside the housing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-174126 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-described heat dissipation structure, dust, rainwater, etc. enter the housing through the air intake and exhaust ports, and therefore, it is not suitable for products that require dustproofness and waterproofness.

[0005] SUMMARY OF THE INVENTION An object of the present invention is to provide a heat dissipation structure that can ensure dustproofness and waterproofness. [Means for solving the problem]

[0006] The heat dissipation structure according to the first aspect is configured to cool a heat generating element. The heat dissipation structure includes a housing, a heat dissipation mechanism, and a sealing member. The housing accommodates the heat generating element. The heat dissipation mechanism has a heat transfer section and a heat dissipation section. The heat transfer section is disposed within the housing. The heat transfer section is configured to transfer heat from the heat generating element. The heat dissipation section is disposed outside the housing. The sealing member seals between the heat dissipation mechanism and the housing.

[0007] With this configuration, heat from the heat generating element housed in the housing is transferred to the heat dissipation section via the heat transfer section, and is then released to the atmosphere outside the housing by the heat dissipation section. Furthermore, since the space between the heat dissipation mechanism and the housing is sealed with a sealing member, dustproofness and waterproofness can be ensured.

[0008] A heat dissipation structure according to a second aspect is the heat dissipation structure according to the first aspect, wherein the heat dissipation mechanism is a heat sink formed of a single member.

[0009] A heat dissipation structure according to a third aspect is the heat dissipation structure according to the first or second aspect, further comprising a heat shield arranged to surround the heat transfer portion.

[0010] A heat dissipation structure according to a fourth aspect is the heat dissipation structure according to any one of the first to third aspects, further comprising a mounting bolt that penetrates the housing and extends to the outside of the housing. The heat dissipation portion has a threaded hole that does not penetrate the housing. The mounting bolt is screwed into the threaded hole.

[0011] A heat dissipation structure according to a fifth aspect is the heat dissipation structure according to any one of the first to fourth aspects, wherein the housing has an opening that connects the inside and outside of the housing. The opening faces horizontally.

[0012] A heat dissipation structure according to a sixth aspect is the heat dissipation structure according to the fifth aspect, further comprising an electronic board disposed within the housing, the heat generating element being attached to the electronic board, and the electronic board being disposed so as to face the opening.

[0013] A drive unit according to a seventh aspect includes the heat dissipation structure according to any one of the first to sixth aspects, a battery, and an electric motor. The battery is disposed in a housing. The electric motor is driven by the battery. [Effects of the Invention]

[0014] According to the present invention, a heat dissipation structure that is dustproof and waterproof can be realized. [Brief explanation of the drawings]

[0015] [Figure 1] Side view of a pallet truck. [Figure 2] FIG. 3 is a cross-sectional view of the heat dissipation structure as viewed from above. [Figure 3] FIG. 4 is an enlarged cross-sectional view of the heat dissipation structure as seen from the side. [Figure 4] FIG. 4 is an enlarged cross-sectional view of the heat dissipation structure as viewed from above. DETAILED DESCRIPTION OF THE INVENTION

[0016] The heat dissipation structure according to this embodiment will be described below with reference to the drawings. FIG. 1 is a side view of a pallet truck equipped with a drive unit to which the heat dissipation structure according to this embodiment is applied. The drive unit to which this heat dissipation structure is applied can also be installed in moving objects other than pallet trucks (for example, hand lift trucks, hand trucks, or wheelchairs). This heat dissipation structure can also be applied to electrical products other than drive units.

[0017] As shown in Figure 1, the pallet truck 200 has a pallet truck body 210 and a drive unit 20. The pallet truck body 210 has a loading platform (a pair of fork arms) 201, an operating handle 202, and a plurality of wheels 204. Each wheel 204 is a non-drive wheel. The drive unit 20 is attached to the pallet truck body 210.

[0018] <Drive unit> The drive unit 20 includes an electric motor 21, a battery 22, and a heat dissipation structure 100. The drive unit 20 also includes drive wheels 24, a reducer 25, and the like.

[0019] When a user is manually driving the pallet truck 200, the electric motor 21 outputs an assist force for assisting the driving of the pallet truck 200. The electric motor 21 drives the drive wheels 24 to rotate.

[0020] The battery 22 is configured to supply power to the electric motor 21 and the like. The electronic board 9 is electrically connected to the battery 22. A plurality of semiconductor elements and the like are soldered to the electronic board 9. The battery 22 and the electronic board 9 are housed in a housing 3, which will be described later.

[0021] The reducer 25 reduces the rotation speed of the electric motor 21 and transmits the rotation speed to the drive wheels 24. The reducer 25 is made up of, for example, a plurality of gears.

[0022] [Heat dissipation structure] Fig. 2 is a cross-sectional view of a heat dissipation structure viewed from above. As shown in Fig. 2, heat dissipation structure 100 is configured to cool multiple heat-generating elements 101. Heat dissipation structure 100 has a housing 3, a heat dissipation sheet 4, a heat dissipation mechanism 5, a sealing member 6, and a heat shield 7. Heat dissipation structure 100 also has multiple mounting bolts 8 and an electronic board 9 (see Fig. 4).

[0023] [Case] The housing 3 is configured to house various components. Specifically, the housing 3 houses an electronic board 9 therein. The housing 3 also houses a battery 22 therein. The housing 3 is airtight to prevent dust, rainwater, and the like from entering inside.

[0024] The housing 3 has a first space 31 that houses the electronic board 9 and a second space 32 that houses the battery 22. That is, the housing 3 is divided into two spaces by a partition wall 33. The housing 3 is made of a synthetic resin such as ABS (acrylonitrile butadiene styrene) resin, ASA (acrylonitrile styrene acrylate) resin, or PES (polyethersulfone) resin.

[0025] The electronic substrate 9 is placed vertically within the housing 3. That is, the electronic substrate 9 is arranged along the vertical direction. A plurality of heating elements 101 are soldered onto the electronic substrate 9. The heating elements 101 are, for example, semiconductor elements such as transistors. The heating elements 101 are arranged on the first main surface 91 side of the electronic substrate 9. Heat generated from the heating elements 101 is conducted to the heat dissipation sheet 4 arranged on the second main surface 92 side of the electronic substrate 9 through thermal vias (not shown) formed in the electronic substrate 9. Note that the heating elements 101 may be arranged on the second main surface 92 side of the electronic substrate 9 and be in direct contact with the heat dissipation sheet 4.

[0026] The housing 3 has an opening 34. The opening 34 connects the inside and outside of the housing 3. The opening 34 is formed in a side wall 35 of the housing 3. The side wall 35 faces the electronic substrate 9. The opening 34 penetrates the side wall 35 in a first direction. When viewed in this first direction, the multiple heating elements 101 are arranged to fit within the opening 34. In this embodiment, the opening 34 faces the horizontal direction. The electronic substrate 9 is arranged to face the opening 34. Specifically, a second main surface 92 of the electronic substrate 9 faces the opening 34.

[0027] [Heat dissipation sheet] The heat dissipation sheet 4 is disposed between the plurality of heat generating elements 101 and the heat dissipation mechanism 5. In this embodiment, the heat dissipation sheet 4 is disposed between the plurality of thermal vias that transfer heat from the heat generating elements 101 and the heat dissipation mechanism 5. The heat dissipation sheet 4 is in contact with the plurality of thermal vias and the heat dissipation mechanism 5. The heat dissipation sheet 4 is configured to fill in the gaps between the thermal vias.

[0028] [Heat dissipation mechanism] Fig. 3 is an enlarged cross-sectional view of the heat dissipation structure as seen from the side. As shown in Figs. 2 and 3, the heat dissipation mechanism 5 has a heat transfer section 51 and a heat dissipation section 52. The heat transfer section 51 and the heat dissipation section 52 are each formed from a single member. The heat dissipation mechanism 5 is, for example, a heat sink formed from a single member. The heat dissipation mechanism 5 extends from inside the housing 3 to the outside through the opening 34.

[0029] The heat transfer section 51 is disposed within the housing 3. The heat transfer section 51 may be disposed from inside the housing 3 to the outside. The heat transfer section 51 is configured to transfer heat from the heat generating element 101. In this embodiment, the heat from the heat generating element 101 is transferred to the heat transfer section 51 via thermal vias and the heat dissipation sheet 4. The heat transfer section 51 then transfers the heat to the heat dissipation section 52.

[0030] The heat dissipation section 52 is disposed outside the housing 3. The heat dissipation section 52 is configured to dissipate the heat of the heating element 101, which is transferred via the heat transfer section 51, into the atmosphere outside the housing 3. The heat dissipation section 52 has, for example, heat dissipation fins 521 and a flange section 522. The flange section 522 is formed in an annular shape that is slightly larger than the opening section 34 of the housing 3. The flange section 522 is disposed so as to surround the opening section 34.

[0031] 4, the heat dissipation portion 52 has a plurality of protrusions 523. The protrusions 523 are formed on the flange portion 522. The protrusions 523 protrude from the flange portion 522 to the side opposite to the housing 3.

[0032] The heat dissipation part 52 has a plurality of screw holes 524. Each screw hole 524 is formed in the protrusion 523. Each screw hole 524 is a recess that does not penetrate through. The screw holes 524 do not communicate with the outside of the housing 3. The screw holes 524 open into the housing 3 via through holes in the housing 3. The screw holes 524 and the inside of the housing 3 communicate with each other via openings 61 formed in the seal member 6. Therefore, the screw holes 524 and the inside of the housing 3 communicate airtightly.

[0033] Mounting bolt 8 is threaded into this screw hole 524. The head of mounting bolt 8 is disposed inside housing 3, and the threaded portion extends to the outside of housing 3. Mounting bolt 8 penetrates side wall portion 35 of housing 3 and extends to the outside of housing 3, where it is threadedly engaged with screw hole 524. Heat dissipation mechanism 5 is attached to housing 3 by this mounting bolt 8.

[0034] [Sealing material] As shown in FIGS. 2 to 4, the sealing member 6 provides a seal between the heat dissipation mechanism 5 and the housing 3. The sealing member 6 is annular. The sealing member 6 is arranged to surround the opening 34. The sealing member 6 is compressed between the housing 3 and the flange portion 522. The sealing member 6 prevents dust and rainwater from entering the housing 3 through the opening 34. The sealing member 6 can be made of, for example, natural rubber, synthetic rubber, a liquid gasket, or a metal seal.

[0035] [Heat shielding section] The heat shield 7 is disposed so as to surround the heat transfer portion 51. The heat shield 7 is cylindrical. Specifically, the heat shield 7 extends along the outer peripheral edge of the opening 34, and extends from the outer peripheral edge of the opening 34 toward the inside of the housing 3. Specifically, the heat shield 7 extends from the side wall portion 35 toward the electronic board 9. Note that the heat shield 7 is disposed with a gap between it and the electronic board 9, but it may also be in contact with the electronic board 9.

[0036] The heat shield 7 is disposed at a distance from the heat transfer part 51. In this embodiment, the heat shield 7 is configured as a part of the housing 3, but the heat shield 7 may be configured as a separate member from the housing 3. The heat shield 7 may also be wrapped around the heat transfer part 51. In other words, the heat shield 7 may be in contact with the heat transfer part 51.

[0037] The heat shield 7 is made of a material with a lower thermal conductivity than the heat transfer part 51. For example, the heat shield 7 can be made of a synthetic resin material such as ABS resin, ASA resin, or PES resin, like the housing 3, or a silicone resin with a lower thermal conductivity than these synthetic resins. By providing this heat shield 7, it is possible to prevent the heat transferred through the heat transfer part 51 from being released into the housing 3.

[0038] [Variations] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and various modifications are possible without departing from the spirit of the present invention. Note that the following modifications can basically be applied simultaneously.

[0039] (a) In the above embodiment, the heat dissipation mechanism 5 is described as a heat sink composed of one member, but the configuration of the heat dissipation mechanism 5 is not limited to this. For example, the heat dissipation mechanism 5 may be composed of two or more members.

[0040] (b) In the above embodiment, only one heat dissipation mechanism 5 is provided, but two or more heat dissipation mechanisms 5 may be provided. [Explanation of symbols]

[0041] 3: Housing 5: Heat dissipation mechanism 51: Heat transfer section 52: Heat dissipation part 6: Sealing material 7: Heat shielding section 8: Mounting bolt 20: Drive unit 21: Electric motor 22: Battery 23: Electronic board 100: Heat dissipation structure 101: Heating element 524: screw hole

Claims

1. A heat dissipation structure for cooling a heat generating body, a housing that houses the heating element; a heat dissipation mechanism including a heat transfer unit disposed within the housing and configured to transfer heat from the heat generating element, and a heat dissipation unit disposed outside the housing; a sealing member that seals between the heat dissipation mechanism and the housing; A heat dissipation structure.

2. the heat dissipation mechanism is a heat sink formed of a single member, The heat dissipation structure according to claim 1 .

3. Further, a heat shield portion is provided so as to surround the heat transfer portion. The heat dissipation structure according to claim 1 .

4. Further, a mounting bolt is provided which penetrates the housing and extends to the outside of the housing. the heat dissipation portion has a screw hole that does not penetrate through, The mounting bolt is threaded into the screw hole. The heat dissipation structure according to claim 1 .

5. the housing has an opening that allows the inside and outside of the housing to communicate with each other, The opening faces horizontally. The heat dissipation structure according to claim 1 .

6. further comprising an electronic board disposed within the housing; the heating element is attached to the electronic board, The electronic substrate is disposed so as to face the opening. The heat dissipation structure according to claim 5 .

7. The heat dissipation structure according to any one of claims 1 to 6, a battery disposed within the housing; an electric motor driven by the battery; A drive unit comprising:

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