CROSS REFERENCE TO RELATED APPLICATION

This application is a U.S. national stage application of International Application No. PCT/JP2017/024348, filed on Jul. 3, 2017, the contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a heat sink including a pipe through which cooled fluid flows.

BACKGROUND

Heat sinks to cool an electronic part are known in the art. Such heat sinks known in the art include a heat sink including a pipe through which cooled fluid flows and a cooling block made of a heat conductive material (refer to, for example, Patent Literature 1). As disclosed in Patent Literature 1, the heat sink includes the cooling block having a placement groove and the pipe pressed against the groove, plastically deformed, and fitted in the groove with no gap therebetween to increase thermal conductivity. A cooling range of the heat sink including the cooling block and the pipe typically depends on the size of the cooling block and the area of contact between the pipe and the cooling block.

The heat sinks known in the art further include a heat sink that is disposed in an air-conditioning apparatus including a refrigerant circuit and cools an electronic part included in a controller by using refrigerant flowing through a pipe included in the heat sink (refer to, for example, Patent Literature 2). In the heat sink disclosed in Patent Literature 2, the flow rate of the refrigerant is adjusted by opening or closing a solenoid valve included in the refrigerant circuit. The electronic part can be kept at a target temperature if the heat sink has a low heat capacity.

PATENT LITERATURE

Patent Literature 1: Japanese Patent No. 4766283Patent Literature 2: Japanese Patent No. 5747968

In the configuration of the heat sink in Patent Literature 1, excessive cooling may cause condensation to form in the vicinity of a heat-generating electronic part (hereinafter, referred to as a “heat emitting element”). A low heat capacity of the heat sink, as in Patent Literature 2, results in an increase in temperature undershoot and overshoot. This makes it difficult to keep the heat emitting element at the target temperature.

SUMMARY

The present invention has been made to solve the above-described problem and aims to provide a heat sink that certainly achieves cooling while preventing the formation of condensation.

A heat sink according to an embodiment of the present invention includes a pipe through which cooled fluid flows and a cooling block having a first face on which the pipe is placed and a second face to which a heat emitting element is attached. The cooling block has a contact region and a noncontact region at positions where the cooling block faces the pipe. The first face contacts the pipe in the contact region and faces the pipe with a gap therebetween in the noncontact region. The contact region is located within a projection region defined by projecting a region of attachment of the heat emitting element onto the first face.

In the heat sink according to the embodiment of the present invention, the noncontact region is also located at a position where the cooling block faces the pipe. This arrangement allows the cooling block to have a sufficient heat capacity. Additionally, the contact region is located within the projection region of the region of attachment of the heat emitting element. This arrangement reduces or eliminates excessive cooling in peripheral part of the cooling block. The heat sink according to the embodiment of the present invention thus cools the heat emitting element with certainty while reducing or eliminating the formation of condensation.

