KR20240042689A - Impeller injection mold with improved blade processing precision - Google Patents

Abstract

An impeller injection mold having a structure with improved blade processing precision according to an embodiment of the present invention is provided symmetrically up and down within the injection mold, a plurality of blade grooves formed in a spiral shape at a set height along the circumference of the contact section, and the blade. A blade core set including a blade forming portion equipped with a curved line at the inner end of the groove and forming a blade blade of the impeller; And, a cam core set that surrounds each of the blade core sets and is driven to take out the injection molded impeller. It includes; wherein the upper and lower ends of the blade blade are formed into a rounded structure by the blade forming portion of the blade core set to minimize the occurrence of burrs.

Description

Impeller injection mold with improved blade processing precision}

This relates to an impeller injection mold having a structure with improved processing precision when forming the blade of an impeller used in a fuel pump.

Generally, the motor for the electric pump used in the vehicle fuel system is a brush-type DC motor, and the DC motor is driven by mechanical contact between the brush and the carbon commutator. These DC motors are driven mechanically through contact, and there are problems with wear of the contact part, shortening the durability, noise, and reduced efficiency. In addition, DC motors have a significant decrease in efficiency due to voltage loss caused by the oil film between the brush and the commutator, and the range of speed control is reduced due to this decrease in efficiency.

The BLDC (Brushless DC) motor, which has recently been newly applied as a motor for electric pumps, replaces the role of brushes and commutators with a semiconductor switching element. This has the advantage of widening the range of speed control because there is no voltage loss due to oil film. there is. Additionally, BLDC motors have the advantage of being compact and capable of producing high output due to their high inertia-to-torque ratio. And because BLDC motors do not have brushes or commutators, unlike DC motors, it is expected that noise reduction and efficiency due to mechanical friction will be increased, and the warranty life of vehicle parts will be significantly increased.

As the impeller of the BLDC motor used here rotates by the drive shaft, it forms a spiral flow path with a number of grooves, and along this flow path, fluid passes from the impeller groove through the fixed flow path wall and plays a key role in providing energy. It's a part. These impellers play a significant role as parts that supply fuel, but due to lack of local development of mold production for injection molding, we are entirely dependent on imported molds, and when parts supply is disrupted due to mold problems during domestic production, There is a problem that the period of action is long and the cost aspect is also burdensome.

Among the molds for injection molding such impellers, the blade core undergoes individual finishing work separately after upper and lower core processing, so the corner where the blade blade is formed is not perpendicular but has a processing curve, resulting in a relatively large thickness of the blade blade. The flow rate became smaller. In addition, even if the blade core was cleaned after polishing, the burrs generated during polishing were not properly removed, and burrs remained at the corners and did not fall off even when high-pressure spraying occurred.

In addition, when cleaning the blade core with high-pressure spray, there was a problem in that the blade forming part was broken due to the high-pressure spray. In addition, when the alignment of the blade forming parts arranged at the top and bottom was not correct, several trials and errors were required to manually adjust the correction values. Since the adjustment values were not dataized, the entire upper and lower sets were replaced due to damage to the blade core. Because it had to be replaced, there was a significant risk of time and cost.

Republic of Korea Patent Publication No. 10-0840179

The present invention was developed to solve the above-mentioned problems, and the end of the blade blade can be molded into a rounded shape to minimize the occurrence of burrs after injection molding on the blade blade of the impeller for the fuel pump. The purpose is to minimize blade distortion and improve core compatibility by matching the processing standard angle of the cam core coupling portion and the cam curved protrusion when manufacturing an injection mold. It is not limited to the technical challenges described above, and other technical challenges may be derived from the description below.

The present invention for achieving the above object is an injection mold for molding an impeller for a fuel pump, in which a plurality of blade grooves are provided symmetrically upward and downward in the injection mold and are formed in a spiral shape at a set height along the circumference of the contact section. and a blade core set that includes a blade forming portion equipped with a curved line at an inner end of the blade groove and forms a blade blade of the impeller; and a blade core set that surrounds each of the blade core sets and is driven so that the injection molded impeller is ejected. A structure with improved blade machining precision, including a cam core set, wherein the upper and lower ends of the blade blade are formed in a rounded shape by the blade forming portion of the blade core set to minimize the occurrence of burrs. It relates to an impeller injection mold having a.

In addition, the blade core set includes a core body portion extending in a cylindrical shape along the periphery of the blade forming portion; and a plurality of curved portions formed to be stepped on the outside of the core body portion and connected from top to bottom on the outer peripheral surface. It is characterized in that it includes a cam core coupling portion in which two cam core grooves are formed.

Additionally, the cam core set includes a cam body portion surrounding the cam core coupling portion; A cam curved protrusion having a plurality of cam protruding lines formed in a curved shape to correspond to the cam core groove of the cam core coupling portion is formed on the inner peripheral surface of the cam body portion, and in a state in which the cam core coupling portion and the cam curved protrusion are engaged. The blade core set is driven, and the processing reference angle of the cam core coupling portion and the cam curved protrusion is matched.

In addition, the blade core set further includes a flow path forming member disposed between the blade grooves of the blade forming portion and formed in the shape of a blade inclined in one direction, and a pair of the flow path forming members arranged symmetrically up and down. It is characterized in that the thickness of the blade blade is optimized by corner portions forming a right angle in one direction.

In addition, the blade core set includes a plurality of corner portions of the flow path forming body arranged in a straight line to maintain a constant arrangement of the blade blades.

The impeller injection mold having an improved blade processing precision structure according to an embodiment of the present invention having the above configuration has the following advantages.

By allowing the blade forming part to mold the end of the blade into a rounded shape, the generation of burrs is reduced when grinding the upper and lower surfaces of the blade, eliminating the problem of the end of the blade being broken due to high-pressure spraying. It has the advantage of falling easily even if a burr occurs.

In addition, it is possible to eliminate manual deviations and increase precision through electric discharge machining for structures that require existing finishing work. It also sets the standard for electric discharge machining for machining blade core sets and 5-axis machining for machining cam core set shapes. Core compatibility can be improved by matching standards and minimizing blade distortion.

In addition, the blade forming part is manufactured through 5-axis electrical discharge machining, so the corners can be maintained at right angles, and the fuel discharge flow rate can be maximized by optimizing the thickness of the blade by replacing the finishing work with electric discharge work.

In addition, by developing precision injection technology for the impeller, a key element of the electric pump, to develop a high-flow, high-efficiency electric pump for high-performance automobiles, we have localized the mold and are not dependent on imports. During domestic production, there is no disruption in the supply of parts due to mold problems. Even if an incident occurs, the action period is short and the cost is reduced.

In addition, the corner portions of the upper and lower blade forming parts are arranged in a straight line so that the alignment of the blade blade array structure is maintained constant, so there is an advantage in that there is no need to replace the blade core set, thereby eliminating additional time and cost.

Figure 1 is a diagram of an impeller molded using an impeller injection mold with a structure with improved blade processing precision according to an embodiment of the present invention.
Figure 2 is a diagram showing the arrangement of the blade core set and the cam core set of the impeller injection mold having a structure with improved blade processing precision according to an embodiment of the present invention.
Figure 3 is a diagram showing a state in which a single blade core and a single cam core of an impeller injection mold having a structure with improved blade processing precision according to an embodiment of the present invention are combined.
Figure 4 is a cross-sectional view of an impeller molded using an impeller injection mold with a structure with improved blade processing precision according to an embodiment of the present invention.
Figure 5 is a comparative illustration of a conventional blade blade molded using an injection mold and a blade blade molded using an impeller injection mold according to an embodiment of the present invention.

Hereinafter, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. The present invention may be implemented in many different forms and is not limited to the structure or method described herein.

In an embodiment of the present invention, the end of the blade blade can be molded into a rounded shape structure to minimize the occurrence of burrs after injection molding on the blade blade of the impeller for a fuel pump, and the cam core is combined when manufacturing the injection mold. This relates to an impeller injection mold with a structure with improved blade processing precision that can minimize blade distortion and improve core compatibility by matching the processing standard angle of the portion and the cam curved protrusion. Hereinafter, it is briefly referred to as "impeller injection mold." We will refer to it as ".

Figure 1 is a diagram of an impeller molded using an impeller injection mold with a structure with improved blade processing precision according to an embodiment of the present invention. Referring to FIG. 1, the impeller of the fuel pump rotates by the drive shaft, forming a spiral flow path with a plurality of flow grooves 12, and along this flow path, fluid passes from the flow path grooves 12 through the flow path wall and releases energy. It is a key part that plays a role in providing .

In this way, the impeller 10, which is molded in the impeller injection mold 1000, moves fluid from the lower inlet to the upper outlet by the blade blade 11 moving in the flow region, transmits centrifugal force to the surroundings, and consists of a plurality of blade blades. By creating a regular circular flow with (11), the increased fluid velocity can be converted into flow rate and pressure according to the flow resistance.

At this time, the conventional injection molded impeller 10 did not fall off even with high-pressure spraying because burrs generated during polishing were not properly removed, and there was a problem in that the end of the blade was broken due to high-pressure washing. To solve this problem, by using the impeller injection mold of the present invention, the end of the blade blade can be made into a rounded shape, which not only reduces the occurrence of burrs, but also prevents the end of the blade from breaking due to high-pressure injection. You can.

Figure 2 is a diagram showing the arrangement of the blade core set and cam core set of an impeller injection mold with a structure with improved blade processing precision according to an embodiment of the present invention, and Figure 3 is a diagram showing the blade processing according to an embodiment of the present invention. This is a diagram showing a state in which a single blade core and a single cam core of an impeller injection mold with a structure with improved precision are combined. Referring to Figures 2 and 3, the blade core set 100 and the cam core set 200 in the impeller injection mold have a structure in which they are symmetrically arranged vertically and combined.

The blade core set 100 is configured to form a plurality of blade blades 11 of the impeller 10. This blade core set 100 is provided symmetrically in the injection mold 1000 with single blade cores facing each other vertically about an axis to form a set. In detail, the blade core set 100 includes a blade forming portion 110 that forms the shape of the blade blade 11, a core body portion 120 that forms a driving space, and a cam core that is coupled to the drive of the cam core set. It may include a coupling portion 130.

The blade forming portion 110 is formed in a cylindrical shape, has a plurality of blade grooves 111 formed in a spiral shape at a set height along the circumference of the contact section where two single blade cores come into contact, and an inner end of the blade groove 111. A rounded curved line 112 may be provided. Here, the injection molded blade blade 11 may be formed in the shape of ">" or "<" depending on the shape and structural characteristics of the blade groove 111 and the curved line 112, and the end of the blade blade 11 The portion 11a is formed in a rounded shape to minimize the occurrence of burrs.

Additionally, the blade forming portion 110 is disposed between the plurality of blade grooves 111 and may further include a blade-shaped flow path forming member 113 inclined in one direction. This flow path forming body 113 forms the flow path groove 12 of the impeller 10 so that fluid can rotate and flow by the blade blade 11. In addition, a corner portion 113a formed at a right angle in one direction is formed by a pair of passage forming members 113 arranged symmetrically up and down, thereby optimizing the thickness of the blade blade 11, which makes it possible to optimize the thickness of the impeller 10. By expanding the flow path 12, the fuel discharge flow rate can be maximized.

Figure 4 is a cross-sectional view of an impeller molded using an impeller injection mold with a structure with improved blade processing precision according to an embodiment of the present invention, and Figure 5-(a) shows a conventional blade blade molded using an injection mold. 5-(b) is a view showing a blade blade molded using an impeller injection mold according to an embodiment of the present invention. Referring to Figures 4 and 5, the blade blade 11 of the impeller 10 has an edge 11b at a right angle due to the corner 113a of the blade forming portion 110, and no distorted shape occurs. By doing so, the alignment of the blade blade 11 can be achieved.

Referring to Figures 2 and 3, the core body portion 120 extends along the outer peripheral surface of the blade forming portion 110 and has a cylindrical shape. At this time, the core body portion 120 serves as a connecting axis between the blade forming portion 110 and the cam core coupling portion 130, and the lengths of the core body portions 120 arranged up and down may be applied differently. In particular, the core body portion 120 is formed with a rectangular guide groove 121 perpendicular to the outer peripheral surface, so that dimensional accuracy can be improved through a structure that allows processing and alignment at an accurate position.

The cam core coupling portion 130 is formed to be stepped on the outside of the core body portion 120, and a plurality of cam core grooves 131 in a curved shape connected spirally from top to bottom are formed on the outer peripheral surface. At this time, the cam core groove 131 is formed as a long groove with a trapezoidal shape and a spiral curve, and is provided to guide the blade core set 100 while being engaged with the cam core set 200 so that the blade core set 100 can move while rotating. These cam core grooves 131 allow the blade core set 100 to move, making it easy to remove the impeller.

The cam core set 200 surrounds each blade core set 100 and is driven so that the injection molded impeller 10 is ejected. This cam core set 200 may include a cam body portion 210 into which the cam core coupling portion 130 is inserted, and a cam curved protrusion 220 engaged with the cam core groove 131. The cam core set 200 is equipped with a fixing groove formed on the edge so that it can be fixedly coupled to the impeller injection mold 1000. At this time, the cam core set 200 is made up of fastening bolts for easy assembly and disassembly, making work easy and repair and maintenance easy, thereby improving operator convenience.

The cam body portion 210 is made in the shape of a square box and has a cylindrical shape penetrating about the central axis so that the cam core coupling portion 130 can be inserted. At this time, the cam body portion 210 is preferably formed to be larger than the outer peripheral surface of the cam core coupling portion 130 so that the cam core coupling portion 130 can be moved by driving. In addition, the cam body portion 210 is formed and installed to be longer than the height of the cam core coupling portion 130 so that the cam core coupling portion 130 can be moved stably without shaking. In addition, the cam body portion 210 is formed with a plurality of fastening holes penetrating from the top to the bottom of the edge so that it can be connected to another core.

The cam curved protrusion 220 has a plurality of cam protrusion lines 221 formed in a spiral curve shape to correspond to the shape of the cam core groove 131 of the cam core coupling portion 130 on the inner peripheral surface of the cam body portion 210. do. At this time, the cam protrusion line 221 and the cam core groove 131 can be formed at four edges around the central axis, and the cam protrusion line 221 is driven to move along the cam core groove 131. Allows it to move evenly across four points. In particular, the cam protrusion line 221 and the cam core groove 131 match the machining reference angles to prevent and minimize the phenomenon of the angle of the blade 11 being distorted, thereby improving core compatibility.

These blade core sets (100) and cam core sets (200) are processed using 5-axis electric discharge machining (EDM), a method of processing materials using sparks generated when the positive and negative electrodes of electricity collide. The advantage is that there is little deformation of the material and precision processing is possible. In addition, processing time is shortened with one setting, high-quality products can be produced through complete processing with a single setting, and tool life is increased with optimal tool use. In addition, there are advantages such as shortening the process and delivery date by minimizing post-work (discharge and polishing), and as precision increases, surface roughness is also improved, eliminating deviations caused by manual work and increasing precision.

In particular, the right angle to the corner portion 113a of the blade forming portion 110 can be maintained through 5-axis electrical discharge machining, and the fuel discharge flow rate can be maximized by optimizing the thickness by replacing the finishing operation with the discharge operation. In addition, dimensional precision can be improved by changing the guide structure of the blade core set to a pin to enable processing and alignment at the exact position. In addition, the corner portions 113a of the blade forming portions 110 arranged vertically through 5-axis electrical discharge machining are arranged in a straight line to maintain the alignment of the blade blades 11 at a constant level, thereby forming the blade core set 100. Since there is no need to replace it, there is an advantage in that additional time and costs are not incurred.

The impeller injection mold 1000 according to an embodiment of the present invention allows the end of the blade blade 11 to be molded into a rounded shape by the blade forming portion, thereby creating a burr when grinding the upper and lower surfaces of the blade blade 11. ) is reduced, eliminating the problem of the end of the blade 11 being broken due to high-pressure spraying, and has the advantage of falling off easily even if burrs occur.

A person skilled in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the equivalent scope should be construed as being included in the present invention.

10: impeller
11: blade blade
11a: end part
11b: edge
12: Euro Home
1000: Injection mold
100: Blade core set
110: blade forming part
111: Blade groove
112: curved line
113: Flow path forming body
113a: corner part
120: Core body part
121: Guide home
130: Cam core coupling part
131: Cam Core Home
200: Cam core set
210: Cam body part
220: Cam curved protrusion
221: Cam protrusion line

Claims (5)

In an injection mold for molding an impeller for a fuel pump,
It is provided symmetrically up and down in the injection mold, and includes a plurality of blade grooves formed in a spiral shape at a set height along the circumference of the contact section and a blade forming portion equipped with a curved line at an inner end of the blade groove, and the impeller. A blade core set forming a blade blade;
It includes a cam core set that surrounds each of the blade core sets and is driven to extract the injection-molded impeller,
An impeller injection mold with a structure with improved blade processing precision, characterized in that the upper and lower ends of the blade blade are formed into a rounded structure by the blade forming portion of the blade core set to minimize burr generation. According to paragraph 1,
The blade core set is,
A core body portion extending in a cylindrical shape along the perimeter of the blade forming portion;
A cam core coupling portion that is formed to be stepped on the outside of the core body portion and has a plurality of cam core grooves formed in a curved shape connected from top to bottom on the outer peripheral surface. It has a structure with improved blade machining precision, comprising a. Impeller injection mold. According to paragraph 2,
The cam core set is,
a cam body portion surrounding the cam core coupling portion;
It includes a cam curved protrusion in which a plurality of cam protruding lines are formed in a curved shape to correspond to the cam core groove of the cam core coupling portion on the inner peripheral surface of the cam body portion,
The blade core set is driven while the cam core engaging portion and the cam curved protrusion are engaged, and has a structure with improved blade machining precision, characterized in that the machining reference angle of the cam core engaging portion and the cam curved protrusion are matched. Impeller injection mold. According to paragraph 1,
The blade core set is,
It further includes a flow path forming body disposed between the blade grooves of the blade forming portion and formed in the shape of a blade inclined in one direction,
An impeller injection mold having a structure with improved blade processing precision, characterized in that the thickness of the blade blade is optimized by a corner portion of a pair of the flow path forming members arranged symmetrically up and down and forming a right angle in one direction. According to paragraph 4,
The blade core set is,
An impeller injection mold having a structure with improved blade processing precision in which a plurality of corner portions of the flow path forming body are arranged in a straight line to maintain a constant arrangement of the blade blades.