EP4143442A1

EP4143442A1 - Water pump for engine cooling system

Info

Publication number: EP4143442A1
Application number: EP21721830.4A
Authority: EP
Inventors: Baocheng Zhang; Guoping Tian; Gengxin Liu; Mengxue QIN; Yan Liu
Original assignee: Caterpillar Motoren GmbH and Co KG
Current assignee: Caterpillar Motoren GmbH and Co KG
Priority date: 2020-04-30
Filing date: 2021-04-16
Publication date: 2023-03-08
Anticipated expiration: 2041-04-16
Also published as: CN211950652U; EP4143442B1; WO2021219245A1

Abstract

The present utility model relates to a water pump for an engine cooling system. The water pump comprises: a water pump housing defining a water sealing hole; a pump shaft rotatably supported in the water pump housing; a water seal sleeved on the pump shaft and positioned in the water sealing hole; an impeller sleeved on the pump shaft and close to the water seal, the impeller comprising a disc, blades arranged on a side of the disc away from the water seal, and at least one balance hole penetrating both end sides of the disc, wherein a central axis of the balance hole is coplanar with a central axis of the pump shaft and inclined at a certain angle with respect to the axis of the pump shaft, and a radial distance of a point on the central axis of the balance hole from the axis of the pump shaft gradually decreases as the point approaches the water seal. The water pump according to the utility model has an improved effect of cooling and lubricating the water seal.

Description

Water Pump for Engine Cooling System

Technical Field

The utility model relates to the field of mechanical pumps, in particular to a water pump used for an engine cooling system. Background Art

As we all know, an engine cooled by a coolant usually requires a water pump to provide a suitable flow rate and head. When the water pump is working, a water seal is usually required to seal the water pump bearing and the pump body. The water seal of the water pump usually includes bellows seat, bellows, spring seat, spring, static ring, dynamic ring, auxiliary sealing ring, etc. When the water pump rotates, the static ring of the water seal is always attached to the dynamic ring of the water seal to form a seal of the coolant.

At present, the following incentives may cause failure of the existing water seal: the local fluidity of the water seal is not uniform, which leads to a rise of the local temperature. In addition, for example, the gas is gathered in the water seal cavity in the process of filling coolant to the engine, causing bubbles to accumulate on the water seal surface to affect the cooling and lubrication of the water seal. Furthermore, when foreign particles enter the friction surface of the water seal or nearby, they are easy to scratch the water seal components and destroy the flatness and roughness of the sealing surface of the water seal, finally resulting in sealing failure of the water seal.

Therefore, the present utility model aims to provide a water pump that can overcome one or more of the above-mentioned problems in the prior art.

Summary of the Invention In order to solve the problems in the prior art, the present utility model proposes a water pump for an engine cooling system, which can improve the flow field distribution around the water seal, avoid the accumulation of foreign matter, bubbles, or the like on the surface of the water seal, thereby improving the cooling and lubrication effects of the water seal and effectively prolonging the service life of the water seal and the water pump.

According to the present utility model, there is provided a water pump for an engine cooling system, comprising: a water pump housing defining a water sealing hole; a pump shaft rotatably supported in the water pump housing; a water seal sleeved on the pump shaft and positioned in the water sealing hole; an impeller sleeved on the pump shaft and close to the water seal, the impeller comprising a disc, blades arranged on a side of the disc away from the water seal, and at least one balance hole penetrating both end sides of the disc, wherein a central axis of the balance hole is coplanar with a central axis of the pump shaft and inclined at a certain angle with respect to the axis of the pump shaft, and a radial distance of a point on the central axis of the balance hole from the axis of the pump shaft gradually decreases as the point approaches the water seal.

In the water pump according to the present utility model, the balance hole in the form of an oblique hole facilitates the flow of water on the surface of the water seal, improves the flow field distribution near the water seal, and improves the lubrication and cooling effects of the water seal.

Advantageously, the central axis of the balance hole is inclined at an angle of about 26 degrees with respect to the axis of the pump shaft. Advantageously, a first annular inner chamber is arranged between the water seal and a side of the disc facing away from the blades around the pump shaft, and a port of the balance hole close to the water seal is connected to the first inner chamber. Advantageously, at least one flushing channel extending in the radial direction is provided in a seat portion of the water pump housing that defines the water sealing hole, wherein a first port of the flushing channel passes through a wall of the water sealing hole into the water sealing hole, a second port of the flushing channel is connected to a second outer chamber, which is in fluid communication with a peripheral chamber defined between the periphery of the impeller and the water pump housing.

Advantageously, the second outer chamber is located on a side of the disc that faces away from the blades and is radially outward with respect to the first inner chamber.

Advantageously, the first port of the flushing channel leads to an area where a friction surface of the water seal is located.

Advantageously, a venting channel is provided in a top area of the seat portion, one port of the venting channel is provided in a wall of the flushing channel located at the top of the seat portion, and another port of the venting channel is configured to lead to a top area of the first inner chamber disposed between the water seal and the disc of the impeller.

Advantageously, the venting channel extends substantially parallel to the axis of the pump shaft, or inclines upward as it extends away from the first inner chamber.

The water pump for the engine cooling system according to the present utility model significantly improves the cooling and lubrication effects of the water seal, and by virtue of the improved flow field distribution near the water seal, avoids the accumulation of foreign matter such as particles or bubbles between the sealing surfaces of the water seal, improves the sealing performance of the water seal, prolongs its service life, and reduces its failure rate. In addition, arranging the balance hole in the form of an oblique hole on the disc of the impeller and arranging the flushing channel and the venting channel on the seat portion of the water pump housing require a simple and cost-effective manufacturing process.

Brief Description of the Drawings

Hereinafter, the preferred embodiments of the present utility model will be described with reference to the accompanying drawings, in which:

Fig. 1 is a cross-sectional view of a water pump for an engine cooling system according to an embodiment of the present utility model;

Fig. 2 is a cross-sectional view of an impeller of a water pump for an engine cooling system according to an embodiment of the present utility model; Fig. 3 shows a seat portion of a housing of a water pump for an engine cooling system according to an embodiment of the present utility model;

Fig. 4 is a cross-sectional view of a seat portion of a housing of the water pump according to an embodiment of the present utility model;

Fig. 5 is an enlarged schematic diagram of a partial detail X in Fig. 4; Fig. 6 is a schematic diagram showing the flow direction of the water during the filling process of the water pump according to an embodiment of the present utility model; and

Fig. 7 is a schematic diagram showing the flow direction of the flushing liquid when the impeller is working in the water pump according to an embodiment of the present utility model.

In order to make the drawings concise, the figures only schematically show the parts related to the present utility model, but do not represent the actual structure of the product. In addition, in order to make the drawings concise and easy to understand, in some drawings, only one of the components with the same structure or function is schematically shown, or only one of them is marked.

Detailed Description of the Embodiments Fig. 1 shows a cross-sectional view of a water pump for an engine cooling system according to the present utility model. The water pump 1 comprises a water pump housing 11 and a pump shaft 12, wherein the pump shaft 12 is rotatably supported in the water pump housing 11. A drive shaft is connected to one end of the pump shaft 12, and the drive shaft inputs power from a power device (not shown) to the pump shaft 12 to drive the pump shaft 12 to rotate. The water pump housing 11 includes a seat portion 111 and a body portion 112 hermetically connected with the seat portion 111. A bearing hole 1111 and a water sealing hole 1112 are defined at corresponding positions of the seat portion 111, and the bearing IB is installed in the bearing hole between the pump shaft and the seat portion. A water seal 14 is sleeved on the pump shaft 12 on the side of the bearing 13 away from the drive shaft. The water seal 14 is installed in the water sealing hole 1112 between the pump shaft 12 and the seat portion 111. An impeller 15 is sleeved at an end of the pump shaft 12 adjacent to the water seal, and the impeller 15 is positioned in the impeller chamber

1120 defined by the body portion 112 of the water pump housing 11. The water seal 14 is configured to seal the area on the side where the bearing 13 is located with respect to the area on the side where the impeller 15 is located, thereby preventing the coolant (for example, water) from entering the area on the side where the bearing 13 is located. The impeller 15 includes a disc 151 and blades 152 provided on the disc. For ease of description, hereinafter, the side of the disc where the blades are provided is referred to as the "front surface of the disc", and the side opposite to the front surface is referred to as the "back surface of the disc". The rotation of the pump shaft 12 drives the impeller 15 to rotate together, and then pressurizes the water (i.e., the coolant) flowing in from the pump inlet 11a by means of centrifugal force, and then discharges the pressurized water from the pump outlet lib, thereby pumping the pressurized water to the engine cooling system for circulation. As can be seen from Fig. 1, the water seal 14 is approximately located at an end area of the seat portion 111. A boss 1115 is provided in an area of the seat portion 111 close to the water sealing hole 1112. An end surface of the boss is provided with a step hole 1116 coaxial with the water sealing hole. An annular flange 153 extends from the disc 151 in the circumferential direction on a side of the impeller 15 close to the water seal (i.e. the back surface), and the annular flange 153 extends into the step hole 1116. An annular gap is provided between the outer circumferential surface of the annular flange 153 and the inner circumferential surface of the large aperture portion of the step hole to ensure that the rotation of the impeller is not disturbed. Thus, a first inner chamber A is roughly defined around the pump shaft between the back surface of the disc and the water seal. The first inner chamber is roughly encapsulated in the circumferential direction by the annular flange 153 and/or the circumferential wall of the step hole 1116. Since the disc of the impeller also includes a portion that extends radially outward with respect to the annular flange, the radially outward area of the impeller chamber 1120 is roughly divided into three chambers: a second outer chamber B located on the back surface of the disc, wherein in the illustrated embodiment, the second outer chamber B is defined by the outer peripheral surface of the boss 1115 and the radially corresponding inner contour of the water pump housing and is substantially annular, and the second outer chamber B is radially outward with respect to the first inner chamber A; a blade chamber C located on the front surface of the disc, wherein the blade chamber is defined by the front surface of the disc or the blades provided thereon and the axially corresponding internal contour of the water pump housing; a peripheral chamber D defined between the periphery of the impeller and the radially corresponding inner contour of the water pump housing, wherein two axial ends of the peripheral chamber D are in fluid communication with the second outer chamber B and the blade chamber C, respectively. The pump outlet lib is provided on a top wall of the peripheral chamber D.

As shown in Figs. 1 and 2, the disc 151 of the impeller 15 is provided with at least one balance hole 1511 in the form of an oblique hole. The central axis of the balance hole 1511 is coplanar with the axis of the pump shaft and is inclined at a certain angle with respect to the axis of the pump shaft. Preferably, the inclination angle is approximately 26 degrees. The radial distance of the point on the central axis of the balance hole 1511 from the axis of the pump shaft gradually decreases in the direction approaching the water seal. The port of the balance hole 1511 close to the water seal leads into the first inner chamber A.

Although only two balance holes are shown in the figure, those skilled in the art can easily imagine that the number of balance holes can be changed according to actual needs. With the aid of the balance hole 1511, a pressure balance between the front and back of the impeller can be achieved. The size of the balance hole cannot be designed too large; otherwise it will affect the efficiency of the water pump. In the illustrated embodiment, the inner diameter of the balance hole is, for example, 8 mm.

As shown in Figs. 1 and 3-5, at least one flushing channel 1113 extending in the radial direction is provided in the boss 1115 in the seat portion 111 of the water pump housing 11, wherein the first port 1113a of the flushing channel 1113 passes through the wall of the water sealing hole 1112 into the water sealing hole, and the second port 1113b of the flushing channel 1113 opposite to the first port leads into a chamber in communication with the peripheral chamber D. Preferably, the second port 1113b leads into the second outer chamber B located near the radially outer circumferential surface of the boss. More advantageously, the first port 1113a of the flushing channel 1113 leads to an area where the friction surface of the water seal 14 is located. As a result, the water flow used as the flushing liquid can directly lead to the friction surface of the water seal to flush it without any large pressure loss. In a preferred embodiment, when the seat portion of the water pump housing is in its installation position, one of the plurality of flushing channels is located in the top area of the seat portion 111. A venting channel 1114 is provided in the top area of the seat portion. One port of the venting channel 1114 is provided in the wall of the flushing channel 1113 at the top of the seat portion, and another port of the venting channel 1114 is configured to lead to the top area of the first inner chamber A between the water seal 14 and the back of the impeller disc 151. During the process of adding coolant to the engine cooling system, the gas entering the first inner chamber A rises to the top of the first inner chamber, then moves to the flushing channel 1113 by means of the venting channel, and then moves up to the second outer chamber B from the flushing channel.

In the water pump according to the present utility model, the arrangements of the balance hole 1511 in the form of an oblique hole and the flushing channel 1113 are helpful for providing an improved fluid circulation on the surface of the water seal 14 and preventing bubbles and particles from accumulating on the surface of the water seal, thus avoiding high heat load and sealing loss caused by foreign matter such as bubbles and particles. With the help of the venting channel, the air is prevented from being trapped in the first inner chamber when the water pump is initially filled, thus avoiding the negative influence of air bubbles formed by air on the flow field distribution near the water seal.

In this article, the technical terms "upper" or "upward" and "top" refer to the relative positional relationship between related parts of the water pump in the installed state or in the working state.

In this article, "first", "second", etc. are only used to distinguish each other, rather than indicating the degree of importance and order, or the premise of mutual existence, etc. Industrial Applicability

In order to better understand the utility model, the work flow is now described below taking the water pump for an engine cooling system as an example: As shown in Fig. 6, when the water pump 1 is initially filled, the water flows in from the pump inlet 11a through the balance hole 1511, the annular gap between the annular flange and the step hole of the boss, and the flushing channel 1113 located in the lower half of the seat portion, and into the first inner chamber A. Because the balance hole is in the form of an oblique hole, it promotes the flow of water on the surface of the water seal. As the filling process progresses, gas will slowly accumulate in the first inner chamber A, and then the bubbles left in the first inner chamber A will gather at the top of the chamber. When the filling level reaches a certain height, the bubbles flow via the venting channel 1114 into the flushing channel 1113 at the top of the seat portion, and then the bubbles are discharged from the pump outlet lib, thus preventing the bubbles from being trapped in the first inner chamber A to affect the sealing performance of the water seal.

As shown in Fig. 7, when the water pump 1 is working, the water flowing through the blade chamber C is thrown to the peripheral chamber D under the action of the centrifugal water pump impeller, and the water flow reaching the peripheral chamber D is in a high-pressure state. At this time, the first inner chamber A between the back of the disc of the impeller of the water pump and the water seal of the water pump is in a low-pressure state. Due to the pressure difference, a part of the pressurized water from the peripheral chamber D flows directly into the first inner chamber A through the gap between the annular flange and the step hole of the boss, and another part of the pressurized water from the peripheral chamber D flows to the second outer chamber B and flows to the water seal 14 through the flushing channel 1113, thereby intensifying the turbulence of the flow field near the water seal, cooling and lubricating the water seal of the water pump, and reducing the damage caused by dry friction of the water seal. Then, the water flow after flushing the water seal enters the first inner chamber A. As the pressure in the first inner chamber A increases, part of the water flows through the balance hole 1511 from the first inner chamber A to the chamber in the central area of the disc on the front side of the disc of the impeller, thereby balancing the pressure on both sides of the impeller.

The embodiments illustrated above are merely the preferred embodiments of the present utility model, and are not used to limit the present utility model. For those skilled in the art, various improvements and modifications can be made to the device of the present utility model without departing from the scope of the utility model. Those skilled in the art can also obtain other embodiments by considering the content disclosed in this specification. This specification and examples should only be regarded as exemplary, and the true scope of the present utility model is defined by the appended claims and equivalent solutions.

Claims

1. A water pump for an engine cooling system, comprising: a water pump housing defining a water sealing hole; a pump shaft rotatably supported in the water pump housing; a water seal sleeved on the pump shaft and positioned in the water sealing hole; an impeller sleeved on the pump shaft and close to the water seal, the impeller comprising a disc, blades arranged on a side of the disc away from the water seal, and at least one balance hole penetrating both end sides of the disc, wherein a central axis of the balance hole is coplanar with a central axis of the pump shaft and inclined at a certain angle with respect to the axis of the pump shaft, and a radial distance of a point on the central axis of the balance hole from the axis of the pump shaft gradually decreases as the point approaches the water seal.

2. The water pump according to claim 1, characterized in that the central axis of the balance hole is inclined at an angle of about 26 degrees with respect to the axis of the pump shaft.

3. The water pump according to claim 1, characterized in that a first annular inner chamber is arranged between the water seal and a side of the disc facing away from the blades around the pump shaft, and a port of the balance hole close to the water seal is connected to the first inner chamber.

4. The water pump according to claim 3, characterized in that at least one flushing channel extending in the radial direction is provided in a seat portion of the water pump housing that defines the water sealing hole, wherein a first port of the flushing channel passes through a wall of the water sealing hole into the water sealing hole, a second port of the flushing channel is connected to a second outer chamber, which is in fluid communication with a peripheral chamber defined between the periphery of the impeller and the water pump housing.

5. The water pump according to claim 4, characterized in that the second outer chamber is located on a side of the disc that faces away from the blades and is radially outward with respect to the first inner chamber.

6. The water pump according to claim 4, characterized in that the first port of the flushing channel leads to an area where a friction surface of the water seal is located.

7. The water pump according to any one of claims 4-6, characterized in that a venting channel is provided in a top area of the seat portion, one port of the venting channel is provided in a wall of the flushing channel located at the top of the seat portion, and another port of the venting channel is configured to lead to a top area of the first inner chamber disposed between the water seal and the disc of the impeller.

8. The water pump according to claim 7, characterized in that the venting channel extends substantially parallel to the axis of the pump shaft, or inclines upward as it extends away from the first inner chamber.