KR101457815B1 - Electric water pump - Google Patents

Abstract

The present invention relates to an electric water pump which can support an axial direction of a shaft, thereby reducing vibration and noise and solving problems of power loss or damage, by reflecting the tendency of maximization and ultra-high-speed extraction to change a two points rotating support structure of the shaft via a pump bush, a bush supporter, and a rotor bush. In particular, the electric water pump can prevent damage to the rotor bush by an elastic force acting in the rotor bush when a driving force of the shaft is generated by a rotor spring for providing an elastic force to push the rotor bush upwards. The present invention can reduce the damage or thermal damage of a friction surface generated during the axial direction and rotational support by improving the lubricity of a refrigerant through a plurality of lubrication holes and lubrication grooves which are formed in the rotor bush, thereby guaranteeing a long life and reliability.

Description

Electric water pump {ELECTRIC WATER PUMP}

The present invention relates to an electric water pump for circulating cooling water for cooling an automobile engine.

Generally, a cooling system provided in an automobile engine is capable of maintaining an appropriate operating temperature in the entire operating range of the engine. This is because the high temperature of the maximum temperature occurring in the combustion process of the mixer, And to prevent deterioration of the main parts such as the head and the piston.

In the cooling system of such an engine, a water pump for pumping cooling water cooled in the radiator and supplying it to the jacket of the engine is applied. The water pump is largely composed of a mechanical water pump and an electric water pump. It is possible to control the engine cooling in an optimal state, to reduce the engine load, to improve the fuel efficiency of the entire vehicle while simplifying the structure around the engine, Water pumps are now widely used.

In the case of the electric water pump, the rotational force of the impeller is transmitted from the electric motor although it varies depending on the type and arrangement of the electric motor operated by the supply of the electric power.

The electric water pump structurally includes an impeller case formed with an inlet for discharging cooling water and an outlet for discharging the cooling water and having an impeller rotatably disposed therein to pump the cooling water, an electric motor coupled to the lower portion of the impeller case, And a motor case for rotating the impeller.

At this time, the electric motor uses a DC motor or a BLDC motor. However, since the DC motor has a bulky volume as compared with the BLDC motor, a separate sealing or bypass line for preventing the cooling water from invading the inside of the DC motor is required. BLDC motors with optimized configurations are dominant.

The electric water pump using the BLDC motor has two structures according to the combination and rotation of the rotating shaft, the rotor and the impeller. First, as shown in FIG. 1, the shaft 20 is disposed at the center of the motor case 10, The stator 30 and the rotor 40 are installed and the rotor 40 is insert injection-molded together with the impeller 50 so as to be rotatably inserted into the shaft 20, So that the impeller 50 is rotated. At this time, a separation preventing ring 60 is coupled to the upper end of the shaft 20 so that the impeller 50 is not moved upward in the axial direction. That is, the shaft 20 rotates integrally with the rotor 40 and the impeller 50 in a fixed state.

However, in the case of fixing the shaft 20, since the integrated insert insert of the rotor 40 and the impeller 50 is inserted and rotated in the fixed shaft 20, the inner surface contacting the outer circumferential surface of the shaft 20 is rotated at a high speed It is liable to be deteriorated to be scratched or damaged, and the rotation center is finely twisted due to thermal expansion, so that power loss and quantitative pumping are difficult. In order to solve this problem, as shown in Patent Document 1, the rotor 40 and the impeller 50 may be injection-molded by secondary insert injection molding using the rotary support bush 70 as an insert on the inner surface of the insert insert. However, in the case of fixing the shaft 20, another problem is that only the lower end of the shaft 20 is fixed, and the upper end is in a free end state, so that there is a problem in firmly fixing the shaft 20. That is, there is no great problem in a small size and a high speed rotation of a certain degree. However, in the trend of increasing the size and the speed of high speed dialing for the large capacity pumping, vibration occurs at the free end of the shaft 20, The difficulty is that there is no choice.

Accordingly, secondly, as in Patent Document 2, the support of the shaft is required to be two-point type, and in the case of the two-point shaft support, the rotor and the impeller are fixedly coupled to the shaft and the shaft, the rotor and the impeller are forced to rotate as one body. In this case, the shaft is rotatably supported by the upper bearing and the lower bearing through a pair of rotating bearings. The rotary bearing usually uses ball bearings. The rotary support of the shaft is not problematic, but there is a problem in axial support by thrust. That is, as the shaft rotates, a thrust is generated in the direction of the impeller to generate an axial movement force. Of course, although the shaft is press-fitted into the rotation bearing, the wear of the ball of the rotation bearing is worsened due to long use, There is a problem that axial movement occurs.

Korean Patent Laid-Open No. 10-2012-0117416 (Publication date October 24, 2012) European Registered Patent Publication EP1361368B1 (Announcement and registration date Jan. 17, 2007)

SUMMARY OF THE INVENTION It is an object of the present invention, which has been devised in order to solve the above problems, to provide a shaft supporting structure for a shaft by changing a conventional two- Thereby providing an electric water pump capable of preventing the axial friction member from being damaged due to thrust and improving the lubricating property of the refrigerant and reducing the heat dissipation and damage of the frictional surface occurring in the axial direction and the rotational support I have to.

Other objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and preferred embodiments with reference to the accompanying drawings.

In order to achieve the above object, an electric water pump according to the present invention includes: an impeller cover having an inlet port through which cooling water flows and an outlet port through which the cooling water flows; and an impeller cover fixedly coupled to a lower portion of the impeller cover, An impeller that is rotatably installed between the impeller cover and the pump body and pumps the cooling water from the inlet port toward the outlet port; A shaft rotatably supported at a center lower portion of the motor case and having an upper end fixedly coupled to the impeller through a shaft hole of the pump body; a stator fixed to an inner diameter side of the motor case; A rotor fixedly coupled to the lower portion of the shaft in the direction of the shaft, A cylindrical pump bush fixedly coupled to the lower portion of the hole to support the rotation of the shaft; an insertion hole formed at a lower center of the upper portion in a container shape having an open top, A bushing supporter having a lower rear end fixedly engaged with the outer step of the shaft and rotating together with the shaft, a second bushing supporter inserted through the upper portion of the bushing supporter after being inserted through the shaft, An annular rotor bushing having an upper surface contacting the lower surface of the pump bush to prevent the shaft from being axially moved upwardly, and a bush supporter inserted into the bush supporter to provide an elastic force to push the rotor bush upward And a plurality of rotor springs.

The rotor bush is characterized in that a plurality of lubricating holes are vertically formed through the rotor bush.

The rotor bush is characterized in that the plurality of lubricating holes are arranged radially symmetrically.

Further, the rotor bush is characterized in that a plurality of lubricating grooves are recessed in the upper surface along the plurality of lubricating holes.

The electric water pump according to the present invention can achieve axial support of the shaft by changing the structure of the conventional two-point rotating support structure of the shaft through the pump bush, the bush supporter and the rotor bush, reflecting the tendency to increase in size and increase in speed It is possible to solve the problem of power loss or breakage as well as vibration and noise reduction.

In particular, it is possible to prevent the rotor bush from being damaged by the elastic force acting on the rotor bush when the thrust of the shaft is generated through the rotor spring that provides the elastic force to push the rotor bush upward, It is possible to reduce the heat dissipation or the damage of the frictional surface generated in the axial direction and the rotation support, thereby securing the reliability with the long life.

1 is a cross-sectional view showing an electric water pump according to the prior art,
2 is a cross-sectional view showing an embodiment of an electric water pump according to the present invention,
Figure 3 is a cross-sectional view of the main portion showing the two-point rotation and axial support of the shaft in the embodiment of Figure 2,
FIG. 4 is an exploded perspective view of the configuration of the recess in the embodiment of FIG. 2,
Fig. 5 is a cross-sectional view showing the main part showing the elastic action of the rotor spring with respect to the rotor bush in the embodiment of Fig. 2,
6 is a cross-sectional view showing another embodiment of the electric water pump according to the present invention,
FIG. 7 is a cross-sectional view of the main portion showing the two-point rotation and axial support of the shaft in the embodiment of FIG. 6,
FIG. 8 is a perspective view showing the rotor bush in the embodiment of FIG. 6,
Fig. 9 is a cross-sectional view showing the main portion of the embodiment of Fig. 6 showing the process of lubricating the refrigerant by the action of the lubricating hole and the lubricating groove of the rotor bush.

Hereinafter, preferred embodiments of the electric water pump according to the present invention will be described in detail with reference to the accompanying drawings.

2 to 9, the electric water pump according to the present invention includes an impeller cover 110, a pump body 120, a motor case 130, an impeller 140, a shaft 150, a stator 160, A rotor 170, a pump bushing 180, a bushing supporter 190, a rotor bushing 200, and a rotor spring 210. 8, the rotor bush 200 may have a lubricating hole 201 and a lubricating groove 202 formed therein.

The impeller cover 110 and the motor case 130 are the outer appearance of the electric water pump according to the present invention as shown in FIGS. 2 and 6, and the impeller cover 110 and the motor case 130, And the motor side composed of the upper impeller 140 side and the lower stator 160 and the rotor 170. [ Various components to be described later are attached and coupled to the inside of the impeller cover 110 and the motor case 130.

2 and 4, the impeller cover 110 is formed with an inlet 111 through which cooling water flows and an outlet 112 through which the cooling water is discharged. The pump body 120 is fixedly coupled to the lower portion of the impeller cover 110 so as to cooperate with the impeller cover 110 and has a shaft hole 111 formed at the center thereof. The motor case 130 is fixedly coupled to the lower portion of the pump body 120. The impeller cover 110, the pump body 120, and the motor case 130 are sequentially connected to each other and are sealed through an O-ring or the like. An impeller 140 to be described later is installed between the impeller cover 110 and the pump body 120. A stator 160 and a rotor 170 are installed between the pump body 120 and the motor case 130, The impeller 140 and the rotor 170 are vertically connected and coupled through a shaft 150 to be described later so that the impeller 140, the rotor 170, and the shaft 150 rotate together.

That is, the impeller 140 is rotatably installed between the impeller cover 110 and the pump body 120 to pump the cooling water from the inlet 111 to the outlet 112. A shaft 150 is provided to rotate the impeller 140.

2 to 4, the lower end of the shaft 150 is rotatably supported at the lower center of the motor case 130 and the upper end of the shaft 150 passes through the shaft hole 121 of the pump body 120, And is fixedly coupled to the impeller 140. The lower end of the shaft 150 is rotatably supported at the lower center of the motor case 130. A bush or the like for rotating support as well as a ball bearing may be installed at the center of the motor case 130. The upper end of the shaft 150 is fixedly coupled to the impeller 140 through the shaft hole 121 of the pump body 120 as shown in FIGS. 3 and 4. Accordingly, the shaft 150 and the impeller 140, Rotate together. The upper end of the shaft 150 may be press-fitted into the impeller 140 or may be secured through an escape prevention ring (not shown), or the impeller 140 may be fixed to the upper end of the shaft 150 It is enough if it can be combined and rotated together.

The stator 160 constitutes a BLDC motor together with a rotor 170 to be described later as shown in FIGS. 2 and 6, and is fixedly installed on the inner diameter side of the motor case 130. As the name implies, the stator 160 is a coil as a stator, and the rotor 170, which will be described later, is a magnet as a rotor. Although not shown in the drawing, a rotor system is formed in the stator 160 according to an electrical signal of a control board (not shown) to rotate the rotor 170, which will be described later.

The rotor 170 is fixedly coupled to the lower portion of the shaft 150 in the inner diameter direction of the stator 160 as shown in FIGS. The shaft 150 and the rotor 170 may be integrally formed by insert injection molding, and the injection-molded rotor 170 may be fixed to the shaft 150 by press-fitting or other fixing methods. The rotor (170) and the shaft (150) are rotatably fixed together in any fixed manner. Accordingly, as described above, the shaft 170 and the impeller 140 as well as the rotor 170 are also fixedly coupled together as a single body and are rotated together. When the rotor 170 rotates through the rotor system of the stator 160 The shaft 150 and the impeller 140 rotate.

Only the lower end of the shaft 150 is rotatably supported and can not be prevented from moving axially upward by the thrust force when the shaft 150 rotates. A bush supporter 190 and a rotor bush 200 to prevent axial movement of the upper portion of the shaft 150 while rotating the upper portion of the shaft 150. [

The pump bush 180 is fixedly coupled to the lower portion of the shaft hole 121 of the pump body 120 in a cylindrical shape as shown in FIGS. 2 to 4 to support the rotation of the shaft 150. The pump bush 180 is made of carbon and fixed to the lower portion of the hole 121 of the pump body 120. The pump bush 180 is fixedly coupled to the pump body 120 and assembled. The pump bush 180 is fixed to the shaft hole 121 of the pump body 120 such that the rotation support bearing is rotatably supported by the lower end of the shaft 150, And supports the rotation of the shaft 150 in a state where the shaft 150 is rotated. In addition, the pump bushing 180 also performs an axial support function in relation to the bushing supporter 190 and the rotor bushing 200 to be described later.

2 to 4, the bush supporter 190 is formed in a container shape having an open upper portion, and has an insertion hole 191 formed at the lower center of the bush. The bush supporter 190 is inserted through the insertion hole 191, And the lower end of the shaft 150 is engaged with the outer step 151 of the shaft 150 to rotate together with the shaft 150. The rotor bush 200 is inserted into the bush supporter 190 through the open top of the bush supporter 190 after being inserted through the shaft 150 in an annular shape and coupled to the inside of the bush supporter 190, And contacts the lower surface of the pump bush 180 to support the shaft 150 so as not to be axially moved upward.

The bush supporter 190 supports the rotor bushing 200 such that the upper surface of the rotor bushing 200 comes into contact with the lower surface of the pump bushing 180 while the bushing supporter 190 is engaged with the outer step 151 of the shaft 150, The upper surface of the bush 200 contacts the lower surface of the fixed pump bush 180 to support the shaft 150 so that the shaft 150 is not moved upward. The bush supporter 190 is fixedly coupled to the shaft 150 and rotates together, and the rotor bush 200 is also coupled to the bushing supporter 190 and rotates together. Thus, the rotor bushing 200 is characterized by its axial support in relation to the pump bushing 180, rather than the function of supporting the rotation of the shaft 150.

The upper surface of the rotor bushing 200 coupled to the inside of the bushing supporter 190 and the lower surface of the pump bushing 180 can contact and rotate, There must be a minimum clearance that can be swept between. The sliding gap between the upper surface of the rotor bushing 200 and the lower surface of the pump bushing 180 causes fine up and down movement when the axial movement of the shaft 150 is caused by the thrust of the shaft 150, Or the lower surface of the pump bush 180 may be damaged by an impact. To prevent this, a rotor spring 210 described later is installed.

2 to 5, the rotor spring 210 is inserted into the bushing supporter 190 to provide an elastic force to push the rotor bushing 200 upward. 5, the lower end of the rotor spring 210 is supported on the inner bottom surface of the bush supporter 190, and the upper end of the rotor spring 210 is installed to elastically press the lower surface of the rotor bush 200 elastically upward The lower surface of the pump bushing 180, which rubs against the upper surface of the rotor bushing 200, can always maintain a contact state. Therefore, even if vibration due to the vertical movement in the axial direction is generated by the thrust of the shaft 150, the upper surface of the rotor bushing 200, which is provided with elastic force by the rotor spring 210, 180 can always be kept in contact and rubbed. In other words, the sliding gap existing between the upper surface of the rotor bushing 200 and the lower surface of the pump bushing 180 increases in the axial direction due to the thrust of the shaft 150, It is possible to always maintain a constant sliding clearance by the elastic force provided by the rotor bush 200 and the pump bush 180, thereby preventing vibration from occurring between the rotor bush 200 and the pump bush 180 and preventing breakage.

Meanwhile, when the rotor bush 200 rotates together with the shaft 150, a friction surface is formed when the upper surface of the rotor bush 200 contacts the lower surface of the pump bush 180. In this case, the rotor bushing 200 is made of a ceramic material and the pump bushing 180 is made of a carbon material. However, when the shaft 150 rotates, The friction resistance can be increased.

6 to 9, a plurality of lubricating holes 201 are formed in the rotor bushing 200 so as to reduce frictional resistance between the lower surface of the pump bushing 180 and the upper surface of the rotor bushing 200 . Referring to FIG. 6, the refrigerant is filled in the motor case 130 through the shaft hole 121 of the pump body 120. Of course, the stator 160 is tightly sealed so that the refrigerant does not flow into the stator 160, but both the rotor 170 and the rotary shaft 150 are in a state of being locked by the refrigerant. However, since the lower surface of the pump bushing 180 and the upper surface of the rotor bushing 200 rotate in contact with each other, the refrigerant can not easily flow into the friction surface. To this end, the rotor bushing 200 is provided with a plurality of lubricating holes 201 are formed so as to pass through the upper and lower portions, it is easier to lubricate the refrigerant on the friction surface between the pump bush 180 and the rotor bush 200.

As shown in FIG. 8, the rotor bush 200 is formed such that the plurality of lubricating holes 201 are radially symmetric with respect to the radial direction of the rotor bushing 200 so as to further increase the lubricating property of the refrigerant on the friction surface between the pump bushing 180 and the rotor bushing 200. And a plurality of lubricating grooves 202 may be formed along the plurality of lubricating holes 201 on the upper surface of the rotor bush 200. [ That is, the refrigerant introduced through the lubricating hole 201 can easily flow into the friction surface along the lubricating groove 202, and further, the contact area of the friction surface can be minimized.

As described above, the electric water pump according to the present invention has a structure in which the two-point rotating support structure of the conventional shaft 150 is rotated by the pump bush 180, the bush supporter 190, and the rotor bush 200 So that the shaft 150 can be supported in the axial direction, thereby reducing vibrations and noise, as well as solving the problems of power loss and damage.

The rotor bush 200 is prevented from being damaged by the elastic force acting on the rotor bush 200 when the thrust of the shaft 150 is generated through the rotor spring 210 which provides an elastic force to push the rotor bushing 200 upward. The lubricating holes 210 and the lubricating grooves 202 formed in the rotor bush 200 can improve the lubricity of the refrigerant and reduce the heat dissipation and damage of the frictional surfaces generated in the axial direction and in the rotational support It can guarantee reliability with long life expectancy.

The embodiments of the present invention described above and shown in the drawings should not be construed as limiting the technical idea of the present invention. The scope of protection of the present invention is limited only by the matters described in the claims, and those skilled in the art will be able to modify the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the scope of the present invention as long as they are obvious to those skilled in the art.

110: Impeller cover
111: inlet 112: outlet
120: pump body 121: shaft hole
130: Motor case
140: Impeller
150: shaft 151: outer step
160:
170: Rotor
180: pump bush
190: Bush supporter 191: Insertion hole
200: Rotor Bush
201: Lubricating hole 202: Lubricating groove
210: Rotor spring

Claims (4)

An impeller cover having an inlet through which the cooling water flows and an outlet through which the cooling water flows,
A pump body fixedly coupled to a lower portion of the impeller cover to be fitted with the impeller cover,
A motor case fixedly coupled to a lower portion of the pump body,
An impeller rotatably installed between the impeller cover and the pump body to pump cooling water from the inlet to the outlet,
A shaft having a lower end rotatably supported at a central lower portion of the motor case and having an upper end fixedly coupled to the impeller through a shaft hole of the pump body,
A stator fixed to the inner diameter side of the motor case,
A rotor fixedly coupled to a lower portion of the shaft in an inner diameter direction of the stator,
A cylindrical pump bush fixedly coupled to the lower portion of the shaft hole of the pump body to support the rotation of the shaft,
A bush supporter having an upper portion opened and an insertion hole penetratingly formed at a central lower portion thereof, a lower end of the bushing supporter being inserted into the upper portion of the shaft through the insertion hole, Wow,
The bush supporter is inserted into the upper portion of the bush supporter through the upper portion of the bush supporter after being inserted into the upper portion of the shaft and is coupled to the inside of the bush supporter so that the upper surface contacts the lower surface of the pump bush, An annular rotor bushing,
The lower end of the bush supporter is supported on the lower surface of the bush supporter and the upper end of the bush supporter is inserted into the bush supporter so as to elastically press the lower surface of the rotor bush upward, And a rotor spring for maintaining the lower surface of the pump bush to be in a contacted state.
The method according to claim 1,
The rotor bush includes:
Wherein a plurality of lubrication holes are formed through the upper and lower portions.
3. The method of claim 2,
The rotor bush includes:
Wherein the plurality of lubricating holes are arranged radially symmetrically.
The method of claim 3,
The rotor bush includes:
Wherein a plurality of lubrication grooves are formed on the upper surface along the plurality of lubricating holes.

Images