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Fluid pump

Fluid pump description/claims

This application claims priority to Japanese Patent Application No. 2006-313363 filed on Nov. 20, 2006, the contents of which are hereby incorporated by reference into the present application.

1. Field of the Invention

The present invention relates to a fluid pump for circulating cooling water that can cool an engine or inverter of a motor vehicle.

2. Description of the Related Art

This type of fluid pump has a casing that comprises a pump chamber and a housing chamber. The pump chamber and the housing chamber are separated by a partition, such that fluid within the pump chamber does not flow into the housing chamber. An impeller is disposed within the pump chamber in a manner capable of rotation. A stator and a control device are disposed within the housing chamber. The control device has a semiconductor device and a terminal. The semiconductor device operates for converting power supplied from the exterior into power for driving the impeller. The terminal electrically connects the semiconductor device with the stator. When the driving power is supplied to the stator, the stator generates driving force for driving the rotation of the impeller. When the impeller has been driven to rotate by the stator, fluid is drawn into the pump chamber and its pressure is increased, then this pressurized fluid is discharged from the pump chamber.

With this fluid pump, power supplied from the exterior is converted into power for driving a motor by the semiconductor device. The semiconductor device generates heat when power supplied from the exterior is converted into power for driving a motor, and consequently this semiconductor device must be cooled. Japanese Laid-open Patent Publication No. 2000-209810 discloses a fluid pump having a metal casing. The semiconductor device is pressed onto and maintained on a wall surface of the metal casing by means of resilient supporting members. The heat generated by the semiconductor device is radiated to the outside air via the metal housing, thus cooling the semiconductor device.

With this type of fluid pump, the external force that the fluid applies to the impeller may vary when the amount of fluid discharged varies during operation. When the external force applied to the impeller varies, the impeller may oscillate about its rotational axis, whereby the casing vibrates. Further, in the case where the fluid pump is attached to the engine room of a motor vehicle, the vibration of the engine is transmitted, whereby the casing vibrates. In the fluid pump disclosed in Japanese Laid-open Patent Publication No. 2000-209810, the semiconductor device is pressed directly onto the metal casing. As a result, there was the problem that the vibration of the casing was also transmitted to the semiconductor device, and this caused a decrease in the durability and reliability of the semiconductor device.

Accordingly, it is an object of the present teachings to provide a fluid pump capable of efficiently cooling the semiconductor device, and capable of reducing the vibration transmitted to the semiconductor device.

In one aspect of the present teachings, a fluid pump may comprise a casing, an impeller, a stator, a semiconductor device, a terminal, and a sheet member. The casing may be provided with a pump chamber, a housing chamber, and a partition that separates the pump chamber and the housing chamber. The impeller may be rotatably disposed within the pump chamber. The stator may be disposed within the housing chamber. The stator generates driving force for driving the rotation of the impeller. The semiconductor device and the terminal may also be disposed within the housing chamber. The terminal electrically connects the semiconductor device to the stator. The sheet member may be disposed within the housing chamber. The first sheet member may have rubber elasticity. The sheet member may include a first plane surface, which makes contact in a planar manner with the semiconductor device, and a second plane surface which makes contact in a planar manner with the partition.

In this fluid pump, the semiconductor device makes contact in a planar manner with the sheet member, and this sheet member makes contact in a planar manner with the partition. As a result, the heat of the semiconductor device is transmitted to the partition via the first sheet member, and is transmitted from the partition to the fluid in the pump chamber. The semiconductor device can thus be cooled efficiently. Further, the sheet member that has rubber elasticity is disposed between the semiconductor device and the partition. As a result, the amount of vibration transmitted from the partition to the semiconductor device is reduced by the sheet member, and the durability and reliability of the semiconductor device can consequently be increased.

In another aspect of the present teachings, a fluid pump may comprise a casing, an impeller, a substrate, a stator, a semiconductor, a terminal, and a sheet member. The casing may be provided with a pump chamber, a housing chamber, and a partition separating the pump chamber and the housing chamber. The impeller may be rotatably disposed within the pump chamber. The substrate, the stator, the terminal, and the sheet member may be disposed within the housing chamber. The stator generates driving force for driving the rotation of the impeller. The semiconductor device may be mounted on an opposite surface of the substrate from the pump chamber side. A first end of the terminal may be fixed to the substrate, and a second end of the terminal may be fixed to the stator. The sheet member may have rubber elasticity. The sheet member may comprise a first plane surface, which makes contact in a planar manner with a surface at the pump chamber side of the substrate, and a second plane surface which makes contact in a planar manner with the partition of the casing. Preferably, the semiconductor device is disposed at a position corresponding to the location where the substrate is making contact with the first plane surface of the sheet member.

In this fluid pump, since the semiconductor device is making thermal contact with the sheet member via the substrate, it is possible to cool the semiconductor device satisfactorily. Further, since the sheet member has rubber elasticity, it is possible to reduce the amount of vibration that is transmitted from the partition to the substrate (and to the semiconductor device).

In another aspect of the present teachings, a fluid pump may comprise a casing, an impeller, a stator, a semiconductor device, and a heat insulating plate. The casing may be provided with a pump chamber, a housing chamber, and a partition separating the pump chamber and the housing chamber. The impeller may be rotatably disposed within the pump chamber. The stator, the semiconductor device, and the heat insulating plate may be disposed within the housing chamber. The stator generates driving force for driving the rotation of the impeller. The semiconductor device is electrically connected to the stator. The heat insulating plate may divide the housing chamber into a stator side and a semiconductor device side. Preferably, the stator is surrounded by the partition and the heat insulating plate.

In this fluid pump, since the stator is surrounded by the partition and the heat insulating plate, heat generated by the stator is prevented from being transmitted to the semiconductor device side. It is thus possible to effectively prevent the semiconductor device from reaching a high temperature.

These aspects and features may be utilized singularly or in combination in order to make an improved fluid pump. In addition, other objects, features and advantages of the present teachings will be readily understood after reading the following detailed description together with the accompanying drawings and claims. Of course, the additional features and aspects disclosed herein may also be utilized singularly or in combination with the above-described aspect and features.

FIG. 1 shows a vertical sectional view of a fluid pump of a first embodiment.

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• Utility Patent

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