JPH0734238Y2 - Water pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a water pump, and more particularly to a water pump for circulating cooling water of an automobile engine.

<< Prior Art >> Conventionally, as such a water pump, for example,
The one described in 63-52999 is known.

In this type, a shaft is rotatably supported by a pump body via a bearing, and an impeller having blades is fixedly provided at one end of the shaft in a direction (referred to as a front side) away from the shaft. A mechanical seal is arranged between the back side base of the impeller and the pump body to prevent water from leaking to the outside.

<Problems to be solved by the invention> However, in such a conventional water pump, if the gap between the back side of the impeller and the pump body is reduced to reduce the size of the pump, the mechanical seal of the back side base of the impeller is reduced. There is a problem that air is easily accumulated near the sliding surface and the sealing performance is impaired.

In particular, in a water pump for circulating cooling water of an automobile engine, the proportion of air mixed in the cooling water is high, and this problem becomes remarkable. When air is generated, the sliding surface of the seal generates heat due to poor lubrication, abnormal wear occurs, and water leakage occurs due to condensation of the antifreezing agent in the cooling water.

An object of the present invention is to provide a water pump that solves the above-mentioned conventional problems and prevents the generation of air pockets, thereby maintaining the sealing performance and preventing water leakage.

<Means for Solving the Problems> In order to achieve the above object, the present invention has an impeller fixed to one end of a shaft rotatably supported by a pump body.
In a water pump in which a mechanical seal is arranged between the back side base of the impeller and the pump body, a balance hole is provided near the boss of the impeller, and a step is formed at the front opening edge of the balance hole. It is characterized by having done.

<Operation> Due to the step formed at the front opening edge of the balance hole near the boss portion of the impeller, a centrifugal force is generated due to the rotation of the impeller, which causes water to flow in the outer radial direction. Then, a negative pressure is generated in the step due to this flow velocity, and the water or the air pool existing on the back side of the impeller is sucked out.

<< Embodiment >> An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the figure, reference numeral 1 denotes a pump body, which rotatably supports a shaft 5 via a bearing 3. Reference numeral 7 is an impeller formed by casting, and 9 is a mechanical seal on the back side of the impeller 7 in which a fixing ring 9D is press-fitted and fixed to the pump body 1.

The mechanical seal 9 includes a retainer 9A, an elastic body 9B fixed to the retainer 9A, a movable ring 9C fixed to a lip portion of the elastic body 9B, and the movable ring 9C including the fixed ring 9D described above.
It has a spring 9E for making pressure contact with.

The impeller 7 has a recessed hole 7A in which one end of a shaft is press-fitted and a recessed ring 7B in which a fixing ring 9D of a mechanical seal 9 is mounted.
And a boss portion 7C in which is formed, a cone-shaped disc rib 7D connected to the boss portion 7C, and an impeller 7E that is formed upright while slightly extending the outer end portion from the disc rib 7D. ing.

A balance hole 15 is provided in the vicinity of the boss portion 7C and at the same radius as the inner end of the blade 7E for maintaining the pressure balance between the front surface and the back side of the impeller 7. Further, a step 12 having a height higher than the center of the impeller 7 is formed at the front opening edge of the balance hole 15, and a return groove 14 is formed at the outer peripheral edge on the back side of the disc rib 7D by casting. Has been done.

In the embodiment having the above structure, when the shaft 5 rotates via the pulley, the impeller 7 also rotates and a predetermined pump action is performed. At this time, the water flows in the outer radial direction along the disk rib 7D by the centrifugal action of the impeller 7 as shown by the arrow in the figure. Then, since a negative pressure is generated at the step 12 by this flow, a pressure difference occurs between the front and back sides of the impeller 7, and water or air pools existing on the back side are sucked out to the front side. Along with this, new water is replenished from the gap between the impeller 7 and the pump body 1 and the recirculation groove 14, and the water recirculates through the balance hole 15, so that the occurrence of air accumulation is prevented.

<Effect of Device> As is apparent from the above description, according to the present invention, the pump action of the impeller causes water to flow in the outer radial direction by the centrifugal force action of the impeller, and this flow causes negative pressure at the step. As a result, the pressures on the front and back sides of the impeller differ, and water or air pools existing on the back side are sucked out to the front side. Along with this, new water is replenished from the gap between the impeller and the pump body, and the water recirculates through the balance hole. As a result, it is possible to obtain a water pump that does not leak water without preventing the accumulation of air on the back side of the impeller and without impairing the sealing performance.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a front view of the impeller in the figure, FIG. 3 is a sectional view taken along the line AA in FIG. 2, and FIG. 4 is a rear view of the impeller in FIG.
The figure is a sectional view taken along the line BB in FIG. 1 …… Pump body 5 …… Shaft 7 …… Impeller 9 …… Mechanical seal 12 …… Step 14 …… Reflux groove 15 …… Balance hole

Claims (1)

[Scope of utility model registration request] 1. A water pump in which an impeller is fixed to one end of a shaft rotatably supported by a pump body, and a mechanical seal is arranged between a back side base of the impeller and the pump body. A water pump characterized in that a balance hole is provided in the vicinity of a boss portion of the impeller, and a step is formed at a front opening edge portion of the balance hole.