Apparatus for cooling a heat-generating member and method

Abstract

A cooling apparatus for cooling a heat-generating member includes a cooling flow path, a condenser, a coolant-returning flow path, a first check valve and a second check valve. The cooling flow path is thermally connected to the heat-generating member. The condenser is connected to a downstream portion of the cooling flow path and condenses a coolant contained in the cooling apparatus after the coolant is evaporated in the cooling flow path. The coolant-returning flow path returns the coolant condensed by the condenser to an upstream portion of the cooling flow path. The first check valve is disposed between the coolant-returning flow path and prevents the coolant from flowing in a reverse direction from the cooling flow path to the first coolant-returning flow path. The second check valve is disposed between the condenser and the coolant-returning flow path and prevents the coolant from flowing in a reverse direction from the first coolant-returning flow path to the condenser.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present system will be apparent from the ensuing description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a side view of a rear section of a vehicle, illustrating the manner in which an in-wheel motor including a first embodiment of a cooling apparatus is mounted;

FIG. 2 is a perspective view of a suspension system illustrating the manner in which the in-wheel motor having a cooling apparatus according to the first embodiment is attached to a vehicle body;

FIG. 3 is a sectional view of the in-wheel motor according to the first embodiment;

FIG. 4 is a sectional view of the in-wheel motor of FIG. 3 taken along line IV-IV;

FIG. 5 is a diagram illustrating the manner in which coolant flows in the first embodiment of the cooling apparatus;

FIGS. 6A and 6B are graphs illustrating the principle of coolant circulation according to the first embodiment, where FIG. 6A shows a pressure difference between an inlet and an outlet for each of first and second check valves and FIG. 6B shows the amount of flow at the inlet of the first check valves;

FIG. 7 is a diagram illustrating the manner in which coolant flows in a second embodiment of the cooling apparatus;

FIG. 8 is a diagram illustrating the manner in which coolant flows in a third embodiment of the cooling apparatus;

FIG. 9 is a perspective view of a suspension system illustrating the manner in which an in-wheel motor having a cooling apparatus according to a fourth embodiment is attached to the vehicle body;

FIG. 10 is a diagram illustrating the manner in which coolant flows in the fourth embodiment of the cooling apparatus;

FIG. 11 is a flowchart illustrating a valve control process performed by a controller according to the fourth embodiment;

FIG. 12 is a perspective view of a suspension illustrating the manner in which an in-wheel motor including a fifth embodiment of the cooling apparatus is attached to the vehicle body;

FIG. 13 is a sectional view of the motor according to the fifth embodiment;

FIG. 14 is a sectional view of FIG. 13 taken along line XIV-XIV thereof;

FIG. 15 is a diagram showing the manner in which coolant flows in the fifth embodiment of the cooling apparatus;

FIGS. 16A and 16B are graphs illustrating the temperature variation as a function of time in a cooling flow path and a flow path, respectively, of the cooling apparatus according to the fifth embodiment;

FIG. 17 is a diagram showing the manner in which coolant flows in a sixth embodiment of the cooling apparatus;

FIG. 18A is an enlarged view of a connection structure that is disposed between flow paths in FIG. 17;

FIG. 18B is a diagram showing the structure of a low-density member viewed in a direction shown by arrow XVIIIB in FIG. 18A; and

FIGS. 19A and 19B are enlarged views of an alternative embodiment of the connection structure that is disposed between flow paths in FIG. 17.

Claims

1. A cooling apparatus for cooling a heat-generating member with a coolant, the cooling apparatus comprising: a cooling flow path that is thermally connected to the heat-generating member and that allows the coolant to pass therethrough;a condenser that is connected to a downstream portion of the cooling flow path and that condenses the coolant after the coolant is evaporated in the cooling flow path;a first coolant-returning flow path that returns the coolant condensed by the condenser to an upstream portion of the cooling flow path;a first check valve that is disposed between the first coolant-returning flow path and the cooling flow path and that prevents the coolant from flowing in a reverse direction from the cooling flow path to the first coolant-returning flow path; anda second check valve that is disposed between the condenser and the first coolant-returning flow path and that prevents the coolant from flowing in a reverse direction from the first coolant-returning flow path to the condenser.

2. The cooling apparatus according to claim 1, wherein the cooling apparatus is disposed in a wheel of a vehicle and the condenser is positioned below the cooling flow path as viewed from the vertical direction of the vehicle.

3. The cooling apparatus according to claim 1, further comprising a first reservoir tank disposed in the first coolant-returning flow path, the first reservoir tank storing at least a portion of the coolant.

4. The cooling apparatus according to claim 3, wherein the first reservoir tank has an atmospheric vent hole.

5. The cooling apparatus according to claim 4, wherein the first reservoir tank has a capacity to store all of the coolant present in the cooling apparatus.

6. The cooling apparatus according to claim 1, further comprising: a second coolant-returning flow path that is connected in parallel with the first coolant-returning flow path and that returns the coolant condensed by the condenser to the upstream portion of the cooling flow path;a second reservoir tank positioned in the second coolant-returning flow path, wherein the second reservoir tank is positioned above the cooling flow path;a three-way valve connected to the condenser by a condenser flow path, wherein the three-way valve selectively switches between the first coolant-returning flow path and the second coolant-returning flow path so as to connect the condenser flow path to the first or second coolant-returning flow paths, respectively, under predetermined conditions;an on-off valve provided in the second coolant-returning flow path at a position downstream of the second reservoir tank;a temperature detector for detecting a temperature in the cooling flow path; anda controller that selectively switches the three-way valve to connect the condenser flow path to the first coolant-returning flow path and opens the on-off valve when the temperature detected by the temperature detector is equal to or higher than a preset temperature, and closes the on-off valve when the temperature detected by the temperature detector is lower than the set temperature.

7. The cooling apparatus according to claim 6, further comprising a liquid-level detector for detecting a liquid level in the second reservoir tank, wherein, when the temperature detected by the temperature detector is lower than the preset temperature, the controller selectively switches the three-way valve to connect the condenser to the second coolant-returning flow path if the liquid level detected by the liquid-level detector is lower than a predetermined level and selectively switches the three-way valve to the first coolant-returning flow path if the liquid level detected by the liquid-level detector is equal to or higher than the predetermined level.

8. The cooling apparatus according to claim 1, further comprising a liquid-coolant supply device that supplies the coolant in the liquid phase to a flow path that is positioned between the condenser and the second check valve.

9. The cooling apparatus according to claim 8, wherein the liquid-coolant supply device supplies the coolant in the liquid phase when the coolant in the flow path positioned between the condenser and the second check valve is in the gas phase.

10. The cooling apparatus according to claim 8, wherein the liquid-coolant supply device includes, an auxiliary cooling flow path that is thermally connected to the heat-generating member and that allows the coolant to pass therethrough;an auxiliary condenser that is connected to a downstream portion of the auxiliary cooling flow path and that condenses the coolant after the coolant is evaporated in the auxiliary cooling flow path;an auxiliary coolant-returning flow path that returns the coolant condensed by the auxiliary condenser to an upstream portion of the auxiliary cooling flow path;a first auxiliary check valve that is disposed between the auxiliary coolant-returning flow path and the auxiliary cooling flow path and that prevents the coolant from flowing in a reverse direction from the auxiliary cooling flow path to the auxiliary coolant-returning flow path;a second auxiliary check valve that is disposed between the auxiliary condenser and the auxiliary coolant-returning flow path and that prevents the coolant from flowing in a reverse direction from the auxiliary coolant-returning flow path to the auxiliary condenser; anda cylinder that is sectioned by a movable piston into a first cylinder chamber and a second cylinder chamber such that the piston is capable of varying volumes of the first and second cylinder chambers, wherein the first cylinder chamber is connected to the auxiliary cooling flow path and the second cylinder chamber is disposed in the auxiliary coolant-returning flow path.

11. The cooling apparatus according to claim 10, wherein the auxiliary cooling flow path is connected to and at least partially disposed in the cooling flow path.

12. The cooling apparatus according to claim 10, further including a flow path that connects the second cylinder chamber to coolant-returning flow path and a third auxiliary check valve that is disposed therein so as to be positioned between the coolant-returning flow path and the second cylinder chamber.

13. The cooling apparatus according to claim 12, wherein the third auxiliary check valve is opened to operatively connect the second cylinder chamber to the coolant-returning flow path when the pressure of the auxiliary flow path is greater than the pressure of the coolant-returning flow path.

14. The cooling apparatus of claim 8, further comprising a liquid coolant supply path that connects to the liquid-coolant supply device to the coolant-returning flow path and a third check valve disposed in the liquid coolant supply path.

15. The coolant apparatus of claim 14, further comprising a connection structure that connects the liquid coolant supply path downstream of the third check valve to the coolant-returning flow path such that the connection structure is disposed between the second check valve and the condenser.

16. The coolant apparatus of claim 15, wherein the connection structure further comprises a low density member having a through hole disposed therein that is positioned so as to be co-axial with the coolant-returning flow path.

17. The coolant apparatus of claim 16, wherein the low density member is constructed of a porous material.

18. The coolant apparatus of claim 15, wherein the connection structure further comprises a selectively movable on-off valve, wherein the valve is opened to operatively connect the coolant-returning flow path to the liquid coolant supply path when the coolant in the coolant-returning flow path is in a gas state and wherein the valve is closed when the coolant returning flow path is in a liquid state.

19. The coolant apparatus of claim 18, wherein the on-off valve is constructed of a memory shape material that is responsive to temperature.

20. A method for cooling a heat-generating member, comprising the steps of: connecting a condenser to a downstream portion of a cooling flow path that contains coolant, wherein the cooling flow path is thermally connected to a heat-generating member,wherein the condenser condenses the coolant after the coolant is evaporated in the cooling flow path;connecting a downstream portion of the condenser to an upstream portion of the cooling flow path with a coolant-returning flow path; andcirculating the coolant by alternately opening and closing a first check valve and a second check valve, wherein the first check valve prevents the coolant from flowing in a reverse direction from the cooling flow path to the coolant-returning flow path and the second check valve prevents the coolant from flowing in a reverse direction from the coolant-returning flow path to the condenser.