CN106163214B

CN106163214B - Electric unit and heat radiation assembly thereof

Info

Publication number: CN106163214B
Application number: CN201510160864.4A
Authority: CN
Inventors: 张艳丽; 史振忠; 侯强
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-04-07
Filing date: 2015-04-07
Publication date: 2020-07-10
Anticipated expiration: 2035-04-07
Also published as: CN106163214A

Abstract

A heat dissipating assembly and an electrical unit including such a heat dissipating assembly are disclosed. The heat dissipation assembly includes: a carrier frame carrying electrical components of the electrical unit and formed with one or more fixing portions in which axially extending slots are formed; a heat dissipating plate formed with a fitting hole axially aligned with the slot in the fixing portion; and a fastening bush which assembles the carrier frame with the radiator panel, includes a body section inserted into the insertion groove and a fixing section inserted and interference-fitted into the fitting hole, and has an axial through hole formed therein.

Description

Electric unit and heat radiation assembly thereof

Technical Field

The present application relates to a heat dissipating assembly in an electrical unit and an electrical unit comprising such a heat dissipating assembly.

Background

Electrical units typically have a plastic frame carrying electrical components, which is often mounted to a thermally conductive sheet metal member to perform functions such as heat dissipation from the frame.

In the prior art, there are various ways to mount a plastic frame to a sheet metal piece. For example, according to one prior art, a gasket is insert-molded in a plastic frame, and a caulking protrusion is formed on a metal plate, the caulking protrusion is passed through the gasket, and the caulking protrusion is deformed to achieve caulking. The disadvantage of this technique is that embedding the injection molded washer in the plastic frame and forming the riveting structure on the metal plate member results in complicated processing, requires a large space for the operation of the riveting tool, and requires additional fixing structures for fixing the metal plate member to other members.

According to another prior art, a hole is machined in a metal plate, a barb is formed on a plastic frame, the barb is passed through the hole in the metal plate from one side, so that the hook head is exposed from the other side and hooked on the metal plate. The disadvantage of this technique is that the barbs are not securely fixed, and the penetration of the barbs through the metal plate can interfere with the installation of the metal plate into other components, requiring additional fastening structures to secure the metal plate member to other components.

According to another prior art, a hole is machined in the metal plate, and a pin is formed on the plastic frame, which is inserted into the hole to create an interference fit, thereby creating a clamping force that secures the plastic frame to the metal plate. A disadvantage of this technique is that to accurately control the interference fit between the plastic frame and the sheet metal piece, the accuracy of the fit affects the clamping force between the two, especially in the presence of multiple fixing points, and furthermore, additional fixing structures/areas are required to fix the sheet metal piece to other parts.

Disclosure of Invention

The present application is directed to a heat dissipation assembly for use in an electrical unit, in which a frame of the electrical unit is easily fixed to a heat dissipation plate member.

To this end, according to one aspect of the present application, there is provided a heat dissipation assembly in an electrical unit, comprising: a carrier frame carrying electrical components of the electrical unit and formed with one or more fixing portions in which axially extending slots are formed; a heat dissipating plate formed with a fitting hole axially aligned with the slot in the fixing portion; and a fastening bush which assembles the carrier frame with the radiator panel, includes a body section inserted into the insertion groove and a fixing section inserted and interference-fitted into the fitting hole, and has an axial through hole formed therein.

According to a possible embodiment, the fastening bushing further comprises a flange portion located on axially opposite sides of the body section from the fixing section, at least a portion of the fixing portion being axially sandwiched between the flange portion and the fin member.

According to a possible embodiment, the radial dimension of the fixed segment is smaller than the body segment, thereby forming a bushing step between the fixed segment and the body segment towards the radiant panel.

According to a possible embodiment, the portion of the fixing portion axially sandwiched between the flange portion and the heat dissipation plate member has an axial compressive deformation capability.

According to a possible embodiment, said axial compression deformability is provided by a plurality of downward projections formed on the bottom surface of said fixing portion.

According to a possible implementation manner, the slot includes a large-diameter slot section and a small-diameter slot section, the flange portion is disposed in the large-diameter slot section, the body section is inserted into the small-diameter slot section, a slot step facing away from the heat dissipation plate is formed between the large-diameter slot section and the small-diameter slot section, and the flange portion is pushed against the slot step.

According to one possible embodiment, the insertion groove, in particular the small-diameter insertion groove section, has a plurality of radially inwardly projecting ridges formed therein, which are radially compressed by the body section when the body section is inserted into the insertion groove, in particular the small-diameter insertion groove section.

According to a possible embodiment, a downwardly protruding collar is formed on the bottom surface of the fixing portion, and the heat dissipation plate has a recess formed at a position corresponding to the collar for receiving the corresponding collar therein.

According to a possible embodiment, the heat dissipating assembly further comprises a heat sink, the carrier frame and the heat dissipating plate being assembled to the heat sink by a fastener passing through the through hole of the fastening bush.

According to another aspect of the present application, there is provided an electrical unit, in particular a DC/AC inverter or a DC/DC converter in a power electronic control unit of an electric vehicle, comprising a heat dissipating assembly as described above.

According to the present application, the manufacture and assembly of the carrier frame and the heat dissipation plate member of the electrical unit can be simplified.

Drawings

The above and other aspects of the present application will be more completely understood and appreciated in view of the following detailed description and in connection with the accompanying drawings, in which:

fig. 1 is an exploded perspective view of a heat dissipating assembly of an electrical unit of the present application;

FIG. 2 is a partial cross-sectional view of the heat dissipation assembly of the present application;

FIG. 3 is a partial cross-sectional view of the heat dissipation assembly of the present application after further installation onto other components;

FIG. 4 is a cross-sectional view of a fastener bushing in the heat dissipation assembly of the present application;

fig. 5 is a perspective view of the fixing portion of the plastic frame in the heat dissipating module of the present application from above;

fig. 6 is a perspective view of the fixing portion of fig. 5 taken from below.

Detailed Description

Some embodiments of the present application will now be described with reference to the accompanying drawings. It should be noted that the figures are merely schematic and are not drawn to scale. It should also be noted that the description of the orientation in this application is based on the orientation shown in the drawings, but that the various components may have a variety of possible orientations depending on the particular application.

Fig. 1 illustrates a heat dissipation assembly of an electrical unit of the present application. According to one possible application, the electrical unit is a DC/AC inverter or a DC/DC converter in a power electronic control unit (PEU) of an electric vehicle.

The electrical unit comprises a carrying frame 1, which is made in one piece from an insulating material, such as plastic, and on the upper side of which the various electrical components of the electrical unit are mounted. Since the electrical components of the electrical unit generate heat during operation, a portion of the heat is dissipated through the supporting frame 1. For this purpose, a heat sink plate 2 is fastened to the underside of the carrier frame 1. The heat dissipation plate 2 is preferably made of a metal having good thermal conductivity, such as copper, and has a substantially flat plate shape with flat upper and lower surfaces and an outer contour substantially corresponding to the carrier frame 1. The upper surface of the radiator panel 2 is conformed to the substantially flat bottom surface of the loading frame 1, and the lower surface is intended to be mounted on the main surface of a radiator or other component.

The carrier frame 1 is fixed to the radiator panel 2 by means of a plurality of fastening bushes 3 to form a radiator assembly. The fastening bush 3 is fixed to the radiator panel 2 through an integrally formed fixing portion 4 of the carrier frame 1. The number of fixing sites 4 is one or more. In the example shown, these fixing locations 4 are distributed evenly along two opposite longitudinal edges of the carrying frame 1.

The fastening bush 3 is a one-piece element made of a hard material, for example steel. As shown in fig. 2 and 4, the fastener bushing 3 includes: a top flange portion 3 a; a body section 3b extending axially downward from the flange portion 3a, the outer periphery of which is substantially cylindrical, and the lower end edge of the body section 3b being chamfered or rounded; and a reduced-diameter fixing section 3c extending axially downward from the lower end of the body section 3b, the outer periphery of which is generally conical (as shown in the drawings) or cylindrical (not shown). The through hole 3d penetrates the entire fastener bushing 3 in the axial direction. The outer circumferential dimension of the fixed segment 3c is smaller than the outer circumferential dimension of the body segment 3b, whereby a downward facing bushing step 3e is formed between the lower end of the body segment 3b and the upper end of the fixed segment 3 c. In the case where the fixing section 3c is conical, the fixing section 3c has a shape that tapers downward in the axial direction. The end (lower end) of the fixing section 3c is chamfered or rounded. The upper and lower surfaces of the flange portion 3a and the bush step 3e are substantially perpendicular to the center axis of the fastening bush 3.

As shown in fig. 2, 5 and 6, the fixing portion 4 of the carrying frame 1 partially protrudes laterally outward from the body portion of the carrying frame 1. The fixing portion 4 is formed with a vertically penetrating insertion groove including a preferably substantially cylindrical upper large diameter insertion groove section 4a located in an upper portion of the fixing portion 4 and a preferably substantially cylindrical lower small diameter insertion groove section 4b located in a lower portion of the fixing portion 4, which are substantially coaxial with each other with an insertion groove step 4c facing upward being formed therebetween. Further, the inner peripheral wall 4d defining the lower small-diameter insert groove section 4b is formed with three or more ridges 4e projecting radially inward. These ridges 4e are preferably evenly distributed around the central axis of the socket. The tip of each ridge 4e projecting toward the central axis of the socket forms a tip.

Further, the lower bottom end of the fixing portion 4 forms a projecting ring 4f projecting downward with respect to the bottom surface of the carrier frame 1 around the lower end portion of the small-diameter socket section 4 b. On the bottom surface of the projecting ring 4f, three or more downward projections 4g are formed. These projections 4g are preferably evenly distributed around the central axis of the socket and are capable of axial compression deformation when subjected to a certain axial pressure.

As shown in fig. 1 and 2, the upper surface of the heat dissipating plate 2 is formed with a recessed groove 2a at a position corresponding to the fixing portion 4 on the carrying frame, for receiving therein a corresponding protruding ring 4 f. Further, the heat radiation plate member 2 is formed with a conical or cylindrical fitting hole 2b corresponding to the shape and size of the fixing section 3c at a position corresponding to the insertion groove in the fixing portion 4.

As shown in fig. 2, and referring to fig. 1, 4-6, to fix the carrier frame 1 to the heat dissipation plate 2, first, the protruding ring 4f of each fixing portion 4 of the carrier frame 1 is inserted into the corresponding sinking groove 2a of the heat dissipation plate 2, so that the protrusion 4g pushes against the bottom of the sinking groove 2 a. In this way, it is easy to preliminarily position the carrier frame 1 with respect to the radiator panel 2. In this state, the fitting hole 2b in the heat dissipation plate member 2 is aligned with the slot (the large diameter slot section 4a and the small diameter slot section 4b) in the carrier frame 1. In this connection, it will be understood that the preliminary positioning structure between the carrying frame 1 and the radiator panel 2 provided by the protruding ring 4f and the corresponding sinking groove 2a may be replaced by any other suitable positioning structure, or even eliminated.

Each fastening bush 3 is then pressed into a socket of a corresponding fastening point 4 in the carrier frame 1, so that the fastening section 3c of the fastening bush 3 is inserted into the fitting hole 2b in the heat sink plate 2. At this time, the flange portion 3a of the fastening bush 3 is located in the large-diameter socket section 4a of the fixing portion 4, the body section 3b is located in the small-diameter socket section 4b of the fixing portion 4, and the lower portion of the fixing portion 4 is axially sandwiched between the flange portion 3a and the heat radiation plate member 2. In this way, the carrier frame 1 is fixed to the radiator panel 2 by means of the fastening bushes 3, thereby forming the preassembled radiator module shown in fig. 2.

In order to achieve a proper fit between the fastening bush 3 and the carrying frame 1 and the radiator panel 2, some dimensions of the fastening bush 3 are defined.

First, the outer diameter of the flange portion 3a is smaller than the inner diameter of the large-diameter socket section 4a so that the flange portion 3a can be accommodated in the large-diameter socket section 4 a.

Further, the outer diameter of the body section 3b is slightly smaller than the inner diameter of the small-diameter socket section 4b, but slightly larger than the diameter of the circle defined by the tip of each ridge 4e in the small-diameter socket section 4 b. The ridges 4e may be slightly radially compressed when the body section 3b is inserted into the small-diameter socket section 4 b. In this way, not only can the fastening bush 3 be fixed radially to the fixing location 4, but also the misalignment between the socket in the fixing location 4 and the mating hole 2b, i.e. the misalignment of the axes thereof, can be compensated for by the different degrees of compression of the ridges 4 e. This mismatch may occur during the machining of the carrier frame 1 and the radiator panel 2. Due to the compensation effect of the compressible ridges 4e, the carrier frame 1 can be fixed to the radiator panel 2 at all fixing locations 4, even if there is a mismatch between the slots in some of the fixing locations 4 and the mating holes 2 b.

Further, the outer diameter of the fixing section 3c is slightly larger than the inner diameter of the fitting hole 2b so that an interference fit is generated therebetween, thereby fixing the fastening bush 3 to the fin member 2.

According to a preferred embodiment, the height of the body section 3b is slightly less than the height of the lower portion of the fixing portion 4 (from the socket step 4c to the lowermost end of the protrusion 4g) in the axial direction, and the sum of the heights of the protruding ring 4f and the protrusion 4g is slightly greater than the depth of the sunken groove 2a, so that, in a state where the bearing frame 1 and the heat radiation plate member 2 are preliminarily assembled together only with the fastening bush 3 without further axial force pushing the fastening bush 3 toward the heat radiation plate member 2, the protrusion 4g is pushed against the groove bottom of the sunken groove 2a, and a certain gap exists between the bush step 3e and the groove bottom of the sunken groove 2a, and between the bottom surface of the bearing frame 1 and the upper surface of the heat radiation plate member 2. Of course, when the material of the bearing frame 1 has certain compressibility, the gap between the bottom surface of the bearing frame 1 and the upper surface of the heat dissipation plate 2 may be smaller than the gap between the bushing step 3e and the bottom of the sink groove 2a, or even there is no gap between the bottom surface of the bearing frame 1 and the upper surface of the heat dissipation plate 2.

After the preassembled heat sink assembly shown in fig. 2 is formed as described above, the preassembled heat sink assembly may be further mounted to a heat sink or other component having a heat dissipating function. For example, as shown in fig. 3, the heat dissipating module is mounted to a cooling plate 5 of the heat sink by a fastener such as a screw 6. The cooling plate 5 is preferably made of a material with good heat dissipation properties, such as aluminum, and may be provided with structures (e.g., fins, etc.) that aid in heat dissipation, and may be equipped with means for active cooling (e.g., fans, etc.). Each screw 6 passes through the through hole 3d in the corresponding fastening bush 3, and is fastened to the cooling plate 5 by screw fitting. During tightening with the screw 6, the screw 6 will exert a gradually increasing axial force on the tightening bush 3. By means of this axial force, the fastening bush 3 axially compresses the lower portion of the fixing portion 4, so that the projection 4g is axially compressively deformed, and finally the bush step 3e is pressed against the bottom of the sink groove 2a, while the bottom surface of the carrier frame 1 abuts against the upper surface of the heat radiation plate member 2, and the lower surface of the heat radiation plate member 2 abuts against the upper surface of the cooling plate 5. In this way, the final heat sink assembly is formed. In the final heat sink assembly, a firm fit between the carrier frame 1, the heat sink plate 2, and the heat sink is achieved by the fastening bushings 3 and the fasteners passing through them, and a close fit with efficient heat conduction is achieved between them.

According to an alternative embodiment, the axial and radial dimensions of the external thread of the screw 6 can be set such that, as the screw 6 is screwed into the through-opening 3d of the clamping bush 3, the body section 3b and/or the fixing section 3c of the clamping bush 3 are slightly spread radially outwards, in order to reinforce the fixing action of the clamping bush 3 on the carrier frame 1 and/or the radiator panel 2.

According to the present application, since the fastening between the carrier frame 1 and the heat dissipation plate member 2 is achieved by the fastening bush 3 at the fastening point 4 of the carrier frame 1, and the fastening bush 3 itself provides a place for further assembling the preassembled heat dissipation assembly formed by the carrier frame 1 and the heat dissipation plate member 2, there is no need to provide additional space for mounting the preassembled heat dissipation assembly to other components. In this way, the construction of the heat sink assembly (pre-assembled and final) and the machining and installation process are simplified.

In addition, the radially compressible ridges 4e are formed in the fixing portions 4 to accommodate the mismatch between the fitting positions of the carrier frame 1 and the heat dissipation plate member 2. Therefore, the machining accuracy requirements for the carrier frame 1 and the heat dissipation plate member 2 can be reduced, thereby reducing the cost of the heat dissipation assembly.

In addition, the fastening and the close fitting between the carrier frame 1 and the heat radiation plate 2 and the fastening and the close fitting between the heat radiation plate 2 and the heat sink are achieved by fastening the carrier frame 1 and the heat radiation plate 2 to the heat sink at the fixing portions 4 with the fastening members. In this way, efficient assembly and heat dissipation is achieved in a simple manner.

Although the present application has been described herein with reference to particular embodiments, the scope of the present application is not intended to be limited to the details shown. Various modifications may be made to these details without departing from the underlying principles of the application.

Claims

1. A heat dissipation assembly in an electrical unit, comprising:

a carrier frame (1) carrying electrical components of an electrical unit and formed with one or more fixing portions (4) in which axially extending slots are formed;

a heat-dissipating plate (2) formed with a fitting hole (2b) axially aligned with the slot in the fixing portion (4);

a fastening bush (3) that assembles the carrier frame (1) with the fin member (2), that includes a body section (3b) and a fixing section (3c), and has an axial through hole (3d) formed therein, the body section (3b) being inserted into the insertion slot, the fixing section (3c) being inserted and interference-fitted into the fitting hole (2 b);

a cooling plate (5);

a screw (6) that passes through the through hole (3d) in the fastening bush (3) and is fastened to the cooling plate (5) by screw-fitting so that the lower surface of the heat radiation plate member (2) is brought into close contact with the upper surface of the cooling plate (5);

wherein the socket is formed with a plurality of radially inwardly projecting ridges (4e) which are equispaced around the central axis of the socket, the distal end of each ridge projecting towards the central axis of the socket forming a tip, the ridges being radially compressed by the body section (3b) when the body section (3b) is inserted into the socket, the mismatch between the socket in the fixing portion (4) and the mating hole (2b) in the fin member (2) being compensated for by different degrees of compression of the respective ridges (4 e).

2. The heat dissipating assembly according to claim 1, wherein the fastening bushing (3) further includes a flange portion (3a), the flange portion (3a) and the fixing segment (3c) being located on axially opposite sides of the body segment (3b), at least a portion of the fixing portion (4) being sandwiched between the flange portion (3a) and the fin member (2) in the axial direction.

3. The radiator assembly according to claim 2, wherein the radial dimension of the fixing segment (3c) is smaller than the body segment (3b), thereby forming a lining step (3e) between the fixing segment (3c) and the body segment (3b) towards the radiator panel (2).

4. The heat dissipation assembly as claimed in claim 2, wherein a portion of the fixing portion (4) axially sandwiched between the flange portion (3a) and the heat dissipation plate member (2) has an axial compressive deformation capability.

5. The heat dissipating assembly of claim 4, wherein the axial compressive deformability is provided by a plurality of downward protrusions (4g) formed on the bottom surface of the fixing portion (4).

6. The heat dissipating assembly of any of claims 2 to 5, wherein the socket comprises a large diameter socket section (4a) and a small diameter socket section (4b), the flange portion (3a) being disposed in the large diameter socket section (4a), the body section (3b) being inserted in the small diameter socket section (4b), a socket step (4c) facing away from the heat dissipating plate member (2) being formed between the large diameter socket section (4a) and the small diameter socket section (4b), the flange portion (3a) being pushed against the socket step (4 c).

7. The heat dissipation assembly as defined in claim 6, wherein the minor-diameter socket section (4b) has the ridges (4e) formed therein, which are radially compressed by the body section (3b) when the body section (3b) is inserted into the minor-diameter socket section (4 b).

8. The heat dissipating assembly as claimed in any one of claims 1 to 5, wherein the fixing portion (4) is formed at a bottom surface thereof with a downwardly protruding collar (4f), and the heat dissipating plate member (2) is formed at a position corresponding to the collar (4f) with a sink groove (2a) for receiving the corresponding collar (4f) therein.

9. An electrical unit comprising the heat dissipation assembly of any of claims 1-8.

10. The electrical unit of claim 9, wherein the electrical unit is a DC/AC inverter or a DC/DC converter in a power electronic control unit of an electric vehicle.