COOLER
A cooler comprising a coolant space (R) which is in contact with a heat dissipator; an inflow-side coolant reservoir (Ri) which is in communication with one end of the coolant space (R) via an inflow-side narrowed portion (Rsi); and an outflow-side coolant reservoir (Ro) which is in communication with another end of the coolant space (R) via an outflow-side narrowed portion (Rso). By forming fins (22, 23) or a guide (24, 25) to stand upright in an area located near a downstream side end portion of the inflow-side coolant reservoir (Ri), the flow channel cross-sectional area is reduced and regulated, and the flow velocity of a coolant in this area is increased.
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The present invention relates to a cooler, and in particular, to an improvement in coolant flow rate.
BACKGROUND ARTIn the field of drive units including an electric motor, a drive unit case for housing the electric motor therein, and an inverter for controlling the electric motor, a drive unit having a cooling structure for cooling the inverter and the electric motor has heretofore been proposed.
The inverter 3 includes a switching transistor that converts a direct current from a battery power source into an alternating current, associated circuit elements, and a circuit substrate on which the switching transistor and the associated circuit elements are provided. The inverter 3 is disposed on the upper face side of a heat sink 53 that is integrally provided with the substrate by being attached to the substrate itself or via another member attached to the substrate. The heat sink 53 is fixed to the bottom portion of an inverter case 7 that houses the inverter 3 therein. The lower face of the heat sink 53 is formed as a heat dissipation surface 53a that is thermally connected to the inverter 3. The inverter case 7 is formed to cover the inverter 3 housed therein to protect the inverter 3 from rainwater or dust.
The electric motor 1 is housed in a drive unit case 2. A spacer 6 is provided on the upper face of the drive unit case 2. The spacer 6 has, on the upper face thereof, an opposing surface 6a that is positioned opposite the heat dissipation surface 53a and is also thermally connected to the electric motor 1. A rectangular recessed portion is formed on the upper face of the spacer 6, so that a coolant space R is formed between the spacer 6 and the lower face of the heat sink 53, or, in other words, the heat dissipation surface 53a in a state in which the heat sink 53 is mounted on the spacer 6. The bottom face of the recessed portion forms the opposing surface 6a. A recessed portion 61 and a recessed portion 62 are formed parallel with each other on the lower face of the spacer 6. In cooperation with the upper face of the drive unit case 2, the recessed portion 61 forms an inflow-side coolant channel Ri, and the recessed portion 62 forms an outflow-side coolant channel Ro.
In the cooling structure, the coolant space R is formed between the heat dissipation surface 53a of the heat sink 53 and the opposing surface 6a of the spacer 6, and a plurality of heat dissipation fins 56 are provided within the coolant space R such that they are arranged parallel with each other and stand upright from the heat dissipation surface 53a toward the opposing surface 6a, and an inter-fin passage Rp through which the coolant flows is formed between every two of the plurality of heat dissipation fins 56 that are positioned adjacent to each other. To provide a sufficient area for heat exchange, the heat dissipation fins 56 are projected to extend from the heat dissipation surface 53a on the heat sink 53 side toward the opposing surface 6a of the spacer 6 within the coolant space R, and traverse the coolant space R in the thickness direction thereof.
The heat dissipation fins 56 are formed by cutting and raising the lower face of the heat sink 53, and the heat dissipation surface 53a is positioned close to the inverter 3 side. In forming the fins 56 to stand upright, the length of the edge portions of the heat dissipation fins 56 is configured to be shorter than the length of the base end portion at the portions in which the fins 56 are formed to stand upright from the surface from which the cutting and raising are performed, and the end faces of the inter-fin passages Rp are inclined with respect to the direction in which the heat dissipation fins 56 stand upright.
An inflow-side coolant reservoir Ri is formed by the recessed portion 61 of the spacer 6 and the upper face of the drive unit case 2 to extend in the direction in which the inter-fin passages Rp are arranged parallel with each other, and an outflow-side coolant reservoir Ro is formed by the recessed portion 62 of the spacer 6 and the upper face of the drive unit case 2 to extend in the direction in which the inter-fin passages Rp are arranged parallel with each other. The inflow-side coolant reservoir Ri and the ends of the inter-fin passages Rp on one side are joined together to communicate therebetween by a narrowed portion Rs that extends throughout the area in which the inter-fin passages Rp are arranged parallel with each other. The outflow-side coolant reservoir Ro and the ends of the inter-fin passages Rp on the other side are joined together to communicate therebetween by a narrowed portion Rs that extends throughout the area in which the inter-fin passages Rp are arranged parallel with each other. Fins 21 are provided to stand upright toward the inflow-side coolant reservoir Ri and the outflow-side coolant reservoir Ro at positions of the drive unit case 2 that are opposite the recessed portions 61 and 62, so that the area for heat transfer is increased.
A side end portion on one side of the spacer 6 has an inflow-side port 51 and an outflow-side port 52 connected thereto in parallel with each other. The inflow-side port 51 allows the coolant to flow into the inflow-side coolant reservoir Ri, and the outflow-side port 52 allows the coolant to flow out of the outflow-side coolant reservoir Ro. The coolant supplied to the inflow-side coolant reservoir Ri by means of a coolant pump 41 provided on the coolant circulation path is allowed to flow through the plurality of inter-fin passages Rp arranged parallel with each other via the narrowed portion Rs, so that the inverter 3 is cooled through the medium of the heat dissipation surface 53a. After cooling the inverter 3, the coolant is caused to flow out to the outflow-side coolant reservoir Ro via the narrowed portion Rs.
PRIOR ART DOCUMENTS Patent Documents
- Patent Document 1: JP 2008-172024 A
However, because the coolant supplied to the inflow-side coolant reservoir Ri selectively flows through the inter-fin passages Rp via a portion of the narrowed portion Rs which is located on the upstream side of the coolant stream, the flow rate of the coolant flowing through the inter-fin passages via a portion of the narrowed portion Rs which is located on the downstream side of the coolant stream is relatively low, and air dwells in a downstream side end portion of the inflow-side coolant reservoir. As a result, a problem may arise in that the cooling performance is degraded.
An object of the present invention is to provide a cooler having an inflow-side coolant reservoir and an outflow-side coolant reservoir which are in communication with coolant passages for a heat dissipation surface, or, in other words, a coolant space, via a narrowed portion, wherein the cooling performance on the downstream side of the inflow-side coolant reservoir is improved.
Means for Solving the ProblemsAccording to one aspect of the present invention, there is provided a cooler comprising a coolant space through which a coolant flows; an inflow-side coolant reservoir which is in communication with one end side of the coolant space via an inflow-side narrowed portion; and an outflow-side coolant reservoir which is in communication with another end side of the coolant space via an outflow-side narrowed portion, wherein the inflow-side coolant reservoir and the inflow-side narrowed portion are formed to extend in a first direction, a coolant supplied to the inflow-side coolant reservoir flows along the first direction, flows through the coolant space via the inflow-side narrowed portion, and flows out to the outflow-side coolant reservoir via the outflow-side narrowed portion, and a regulator is formed in an area located near a downstream side end portion of the inflow-side coolant reservoir, the regulator reducing and regulating a flow channel cross-sectional area to increase a flow velocity of the coolant in this area.
According to one embodiment of the present invention, the regulator comprises fins. The fins may be pin fins.
According to another embodiment of the present invention, the pin fins are formed to be unevenly distributed toward the side with which the inflow-side narrowed portion is in communication.
Further, according to still another embodiment of the present invention, the pin fins are formed to have relatively large fin diameters on the side with which the inflow-side narrowed portion is in communication.
Further, according to still another embodiment of the present invention, the pin fins are formed at a relatively high density on the side with which the inflow-side narrowed portion is in communication.
Further, according to still another embodiment of the present invention, the regulator is a guide formed along the first direction.
Further, according to still another embodiment of the present invention, the guide is composed of a first portion formed along the first direction and a second portion extending in a direction approximately perpendicular to the first direction and restricting a downstream flow of the coolant.
Further, according to still another embodiment of the present invention, the cooler further comprises a second regulator formed further upstream of the area located near the downstream side end portion, the second regulator reducing and regulating the flow channel cross-sectional area of the inflow-side coolant reservoir.
Further, according to still another embodiment of the present invention, the second regulator comprises fins formed along the first direction.
Further, according to still another embodiment of the present invention, the cooler further comprises a third regulator formed between the regulator and the second regulator, the third regulator reducing and regulating the flow channel cross-sectional area of the inflow-side coolant reservoir.
Further, according to still another embodiment of the present invention, the third regulator is a projection formed in the inflow-side coolant reservoir.
Advantages of the InventionBy employing the present invention, the amount of air dwelling in a downstream side end portion of the inflow-side coolant reservoir is reduced, and the cooling performance can be improved.
Embodiments of the present invention will be described below with reference to the drawings. It should be noted that components identical or corresponding to those of the conventional cooling structure illustrated in
First, before description of the embodiments, a basic structure constituting a precondition for the embodiments will be described below. The basic structure of a cooler according to an embodiment includes the same components as those of the conventional cooling structure illustrated in
An inflow-side coolant reservoir Ri is formed by the recessed portion 61 of the spacer 6 and the upper face of the drive unit case 2 to be in communication with the coolant space R. Further, an outflow-side coolant reservoir Ro is formed by the recessed portion 62 of the spacer 6 and the upper face of the drive unit case 2 to be in communication with the coolant space R. The inflow-side coolant reservoir Ri and one end of the coolant space R are brought into communication with each other through a narrowed portion Rs, and the outflow-side coolant reservoir Ro and another end of the coolant space are brought into communication with each other through a narrowed portion Rs.
An inflow-side port 51 that allows the coolant to flow into the inflow-side coolant reservoir Ri is joined to the inflow-side coolant reservoir Ri to communicate therebetween, and an outflow-side port 52 that allows the coolant to flow out of the outflow-side coolant reservoir Ro is joined to the outflow-side coolant reservoir Ro to communicate therebetween. The coolant supplied to the inflow-side coolant reservoir Ri by means of a coolant pump 41 provided on the coolant circulation path is allowed to flow into the coolant space R via the narrowed portion Rs, so that a heat generator such as the inverter 3 is cooled through the medium of the heat dissipation surface 53a. After cooling the inverter 3, the coolant is caused to flow out to the outflow-side coolant reservoir Ro via the narrowed portion Rs. Further, a heat generator present within the drive unit case 2, such as a motor or a reactor, is cooled by the coolant flowing within the inflow-side coolant reservoir Ri. According to the embodiment, by means of the heat sink 53 present on the upper surface of the cooling space R, the cooler 50 cools a heat generator present above the cooling space R, and also cools a heat generator present below the inflow-side coolant reservoir Ri.
The inflow-side port 51 is in communication with one end of the inflow-side coolant reservoir Ri in the x direction, and a coolant is supplied to the inflow-side coolant reservoir Ri through this inflow-side port 51. Although any coolant may be used, for example, cooling water is used. The coolant supplied to the inflow-side coolant reservoir Ri flows into the coolant space R via the narrowed portions Rsia, Rsib, and Rsic formed for each of the three spacers 64a, 64b, and 64c. After flowing through the coolant space R, and cooling a heat generator such as the inverter 3, the coolant flows out to the outflow-side coolant reservoir Ro via the narrowed portions Rsoa, Rsob, and Rsoc formed at the other ends of the spacers 64a, 64b, and 64c. The coolant that has flowed out to the outflow-side coolant reservoir Ro is caused to flow out to the coolant circulation path through the outflow-side port 52.
1 to 2 to 3 to 4.
In other words, the coolant flows in the direction in which the inflow-side coolant reservoir Ri extends (in the x direction). Here, the side communicating with the inflow-side port 51 of the inflow-side coolant reservoir Ri is defined as the upstream side, and the opposite side is defined as the downstream side.
Further, the coolant that has flowed into the inflow-side coolant reservoir flows into the coolant space R via the inflow-side narrowed portions Rsia, Rsib, and Rsic. Specifically, some of the coolant that has flowed into the inflow-side coolant reservoir Ri diverts and flows into the coolant space R via the inflow-side narrowed portion Rsia of the spacer 64a. Further, some of the coolant flows into the coolant space R via the inflow-side narrowed portion Rsib of the spacer 64b. Still further, some of the coolant flows into the coolant space R via the inflow-side narrowed portion Rsic of the spacer 64c. In
1 to 2 to 5,
1 to 2 to 3 to 6, or
1 to 2 to 3 to 4 to 7.
The coolant that has flowed through the coolant space R and has cooled the heat generator flows out to the outflow-side coolant reservoir Ro via the outflow-side narrowed portions Rsoa, Rsob, and Rsoc, and flows in the order of numbers 8, 9, 10, and 11 shown in
8 to 9 to 10 to 11,
to flow out through the outflow-side port 52.
In summary, the flow of the coolant within the cooler 50 includes three streams of flow:
1 to 2 to 5 to 10 to 11,
1 to 2 to 3 to 6 to 9 to 10 to 11, and
1 to 2 to 3 to 4 to 7 to 8 to 9 to 10 to 11.
These streams of the coolant cool the heat generator present on the upper face of the cooling space R, and cool the heat generator present on the lower face of the inflow-side coolant reservoir Ri.
Among the above-described streams of the coolant, the stream flowing via the inflow-side narrowed portion Rsia which is located closest to the inflow-side port 51 and is the most upstream among the inflow-side narrowed portions Rsia, Rsib, and Rsic formed in the spacer 64:
1 to 2 to 5 to 10 to 11
has the highest flow rate. The stream flowing via the inflow-side narrowed portion Rsib located next upstream of the inflow-side narrowed portion Rsia:
1 to 2 to 3 to 6 to 9 to 10 to 11
has the second highest flow rate. As such, the amount of the coolant flowing in the order of:
1 to 2 to 3 to 4 to 7 to 8 to 9 to 10 to 11
is relatively low compared to the other streams. In the downstream side end portion of the inflow-side coolant reservoir Ri, or specifically, in the area X illustrated in
To address the above-described situation, according to the embodiment, some improvements to the basic structure are made in order to increase the flow velocity of the coolant flowing in the order of:
1 to 2 to 3 to 4 to 7 to 8 to 9 to 10 to 11.
The basic principles for increasing the flow velocity of the coolant in an area located near the downstream side end portion of the inflow-side coolant reservoir Ri, that is, in the area X, are to reduce the coolant flow channel cross-sectional area in the area X while allowing the coolant to flow into the inflow-side narrowed portion Rsic, so that the flow velocity is increased. In order to reduce the flow channel cross-sectional area in the area X, a regulator for reducing and regulating the flow channel cross-sectional area is formed in the area X. The regulator for reducing and regulating the flow channel cross-sectional area is, for example, a fin which is formed to stand upright in the area X, or a guide which is formed to stand upright in the area X. By increasing the flow velocity of the coolant in an area located upstream of the area X, the flow velocity of the coolant in the area X can also be increased.
The structure of the embodiment will be specifically described below.
2. First EmbodimentAs can be seen from the comparison between
By employing such a structure, the flow velocity of the coolant varies in accordance with the size of the diameters of the pin fins 23, and the flow velocity of the coolant relatively increases in areas where the pin fins 23 have a relatively small diameter. Therefore, air dwelling in the area X is effectively discharged, and the cooling performance in the area X is improved.
Although, according to the present embodiment, the fin diameters of the pin fins 23 vary sequentially in the y direction, the fin diameters of the pin fins 23 may also vary, for example, in two levels so that pin fins 23 having a relatively large fin diameter are formed to stand upright on the side closer to the narrowed portion Rsic, and pin fins 23 having a relatively small fin diameter are formed to stand upright on the opposite side.
4. Third EmbodimentBy employing such a structure, because the guide 24 reduces the flow channel cross-sectional area in the area X of the inflow-side coolant reservoir Ri, the flow velocity of the coolant in the area X relatively increases. As the flow velocity of the coolant relatively increases, air dwelling in the area X is effectively discharged, and the cooling performance is improved.
5. Fourth EmbodimentBy employing such a structure, because the guide 25 reduces the flow channel cross-sectional area in the area X of the inflow-side coolant reservoir Ri, the flow velocity of the coolant in the area X relatively increases, dwelling air is effectively discharged, and the cooling performance is improved.
6. Fifth EmbodimentAlthough the embodiments of the present invention have been described above, other modifications are also possible. For example, in the structure of
Further, in
Further, in
Further, in
Further, in
In summary, the structures of the embodiments of the present invention and their modifications include the following cases, wherein, as illustrated in
(1) The pin fins 22, the pin fins 23, the guide 24, or the guide 25 is formed to stand upright as a regulator in the area X.
(2) The pin fins 22, the pin fins 23, the guide 24, or the guide 25 is formed to stand upright as a regulator in the area X, and the pin fins 22, the pin fins 23, the guide 24, the guide 25, or the rectangular fins 26 are formed to stand upright as a second regulator in the area Y.
(3) The pin fins 22, the pin fins 23, the guide 24, or the guide 25 is formed to stand upright as a regulator in the area X, and the projection 30 is formed as a third regulator in the area Z.
(4) The pin fins 22, the pin fins 23, the guide 24, or the guide 25 is formed to stand upright as a regulator in the area X, the pin fins 22, the pin fins 23, the guide 24, the guide 25, or the rectangular fins 26 are formed to stand upright as a second regulator in the area Y, and the projection 30 is formed as a third regulator in the area Z.
Further, although, according to the embodiments of the present invention, a structure wherein the spacer 64 is divided into three areas, that is, the spacers 64a, 64b, and 64c, as illustrated in
- 22, 23 PIN FIN
- 24, 25 GUIDE
- 50 COOLER
- 51 INFLOW-SIDE PORT
- 52 OUTFLOW-SIDE PORT
- 64 SPACER
- Ri INFLOW-SIDE COOLANT RESERVOIR
- Ro OUTFLOW-SIDE COOLANT RESERVOIR
Claims
1. (canceled)
2. (canceled)
3. A cooler comprising:
- a coolant space through which a coolant flows;
- an inflow-side coolant reservoir which is in communication with one end side of the coolant space via an inflow-side narrowed portion; and
- an outflow-side coolant reservoir which is in communication with another end side of the coolant space via an outflow-side narrowed portion, wherein
- the inflow-side coolant reservoir and the inflow-side narrowed portion are formed to extend in a first direction,
- a coolant supplied to the inflow-side coolant reservoir flows along the first direction, flows through the coolant space via the inflow-side narrowed portion, and flows out to the outflow-side coolant reservoir via the outflow-side narrowed portion, and
- a regulator is formed in an area located near a downstream side end portion of the inflow-side coolant reservoir, the regulator reducing and regulating a flow channel cross-sectional area to increase a flow velocity of the coolant in this area, wherein the regulator comprises pin fins.
4. The cooler according to claim 3, wherein the pin fins are formed to be unevenly distributed toward the side with which the inflow-side narrowed portion is in communication.
5. The cooler according to claim 3, wherein the pin fins have relatively large fin diameters on the side with which the inflow-side narrowed portion is in communication.
6. The cooler according to claim 3, wherein the pin fins are formed at a relatively high density on the side with which the inflow-side narrowed portion is in communication.
7. (canceled)
8. (canceled)
9. The cooler according to claim 3, further comprising:
- a second regulator formed further upstream of the area located near the downstream side end portion, the second regulator reducing and regulating the flow channel cross-sectional area of the inflow-side coolant reservoir.
10. The cooler according to claim 9, wherein the second regulator comprises fins formed along the first direction.
11. The cooler according to claim 9, further comprising:
- a third regulator formed between the regulator and the second regulator, the third regulator reducing and regulating the flow channel cross-sectional area of the inflow-side coolant reservoir.
12. The cooler according to claim 11, wherein the third regulator is a projection formed in the inflow-side coolant reservoir.
Type: Application
Filed: Jan 12, 2011
Publication Date: Nov 7, 2013
Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA (Toyota-shi, Aichi-ken)
Inventor: Keitaro Ishikawa (Toyota-shi)
Application Number: 13/978,665
International Classification: F28F 27/02 (20060101);