Permanent magnet ferrite tile inlay mold

Abstract

The application discloses a permanent magnet ferrite magnetic tile inlaying die, which comprises a punch, a middle die which is sleeved on the punch, and an upper die which is located right above the middle die, wherein the upper die comprises an upper die base body made of a magnetic conductive material and an upper die inlaying layer made of a non-magnetic conductive material; the upper die base body is provided with an upper arc surface which is concave upward at the bottom; the upper die inlaying layer is fixedly embedded in the upper arc surface; and the bottom working surface of the upper die inlaying layer and the upper working surface of the punch jointly form a green body cavity with a rhombic cross section in the cavity of the middle die. The die can meet the requirement of the rhombic permanent magnet ferrite magnetic tile on the distribution of magnetic lines, can meet the magnetic characteristic requirement of the rhombic permanent magnet ferrite magnetic tile without improving the performance grade of raw materials, reduces the process of grinding the magnetic tile into an arc surface with a tangent shape in the later stage, and reduces the waste of raw materials caused by large grinding allowance.

Description

Technical Field

[0001] This invention relates to the field of permanent magnet ferrite tile processing technology, specifically to a permanent magnet ferrite tile inlay mold. Background Technology

[0002] The main component of permanent magnet ferrite tiles is iron oxide. After being pre-fired at high temperature, the particles are crushed into 5um-8um particles by a dry ball mill. Then, these particles, along with a certain amount of water and steel balls, are ground into a slurry of 0.8um-1.2um by a wet ball mill. The slurry is then controlled to have a water content of about 35% by a sedimentation tower. The magnetic domain particles of the slurry are then oriented by a mold under the action of a magnetic field. The slurry is then pressed into a green blank by a hydraulic press, sintered at high temperature into a semi-finished product, and finally ground into the required dimensions.

[0003] Permanent magnet ferrite tiles are used in various micro-motors to provide magnetic fields. The requirements for these magnetic fields vary depending on the application. The generation of the magnetic field in permanent magnet ferrite tiles mainly depends on the orientation and alignment of the N and S poles of the magnetic domain particles in the slurry under the influence of an external magnetic field during the tile forming process. Magnetic tiles are typically semi-circular with an inner and outer arc shape, requiring magnetic lines of force to radiate outwards from the center of the arc. With the mold designed in an arc shape, it is relatively easy to achieve this radial magnetic line distribution. However, the magnetic tiles used in fan motors have a special shape, requiring a thicker center and thinner sides. Typically, the middle part of the outer arc is a circular arc, while the sides are tangentially designed, resulting in a product shape similar to a "rhombus." During molding, because the green blank is thicker in the middle and thinner on the sides, the magnetic lines of force easily pass through the shortest magnetic conduction path between the upper and lower molds. The magnetic domains in the green blank are affected by the magnetic lines of force, and their arrangement changes, no longer radiating outwards. Therefore, magnetic tile molds designed and manufactured according to normal specifications cannot achieve the required magnetic line distribution. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to provide a permanent magnet ferrite tile inlay mold, thereby solving the problem that existing mold designs cannot achieve the required magnetic field distribution when pressing "rhomboid" shaped permanent magnet ferrite tiles.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A permanent magnet ferrite tile inlay mold includes a punch, a middle mold sleeved outside the punch, and an upper mold located directly above the middle mold. The upper mold comprises an upper mold base made of magnetically conductive material and an upper mold inlay layer made of non-magnetically conductive material. The bottom of the upper mold base has an upwardly concave upper arc surface. The upper mold inlay layer is fixedly embedded within the upper arc surface. The bottom working surface of the upper mold inlay layer and the upper working surface of the punch together form a green cavity with a rhomboid cross-section within the cavity of the middle mold.

[0007] As a further aspect of the present invention: the outline of the cross-section of the upper mold inlay layer includes an upper outline, horizontal straight line segments L1 symmetrically distributed on both sides of the upper outline, and a lower outline connecting the two horizontal straight line segments L1, wherein the lower outline does not intersect the upper outline.

[0008] As a further aspect of the present invention: the lower contour line includes an arc segment R0 and two tangent segments L0. The arc segment R0 is located directly below the center of the upper contour line. The two tangent segments L0 are symmetrically distributed on both sides of the arc segment R0, and the two ends of the arc segment R0 are tangently connected to the tangent segments L0 on both sides respectively. The endpoints (a, c) of the two tangent segments L0 away from the arc segment R0 are respectively connected to the endpoints of the corresponding horizontal straight line segments L1.

[0009] As a further aspect of the present invention: the upper contour line is a semi-circular arc R2, and the semi-circular arc R2 matches the cross-sectional contour line of the upper arc surface at the bottom of the upper mold base.

[0010] As a further aspect of the present invention: the three points of the arc vertex b of the arc segment R0 and the endpoints (a, c) of the two tangent segments L0 away from the arc segment R0 are located on the semicircular arc R1, and the semicircular arc R1 and the semicircular arc R2 share the same center O.

[0011] As a further aspect of the present invention: the distance between the arc vertex b of the arc segment R0 and the arc vertex d of the semicircular arc R2 is the thickness T of the upper mold inlay layer, and the radius R2 of the semicircular arc R2 is equal to the radius R1 of the semicircular arc R1 plus the thickness T of the upper mold inlay layer.

[0012] As a further aspect of the present invention, the thickness T of the upper mold inlay layer is 0-15mm.

[0013] As a further aspect of the present invention: the included angle of the arc segment R0 is 0°-180°.

[0014] As a further aspect of the present invention: the outline of the cross-section of the working surface of the punch includes an arc segment R3, an arc segment R4, and a vertical straight line segment L2. The arc segment R3 is located at the center of the cross-section of the working surface of the punch. The center of the arc segment R3 and the center O are located on the same axis. The two endpoints of the arc segment R3 are respectively connected to an arc segment R4. The endpoints of the arc segment R4 away from the arc segment R3 are connected to a vertical straight line segment L2. The endpoints of the two vertical straight line segments L2 away from the arc segment R4 can be connected to the endpoints (a, c) of the two tangent segments L0 away from the arc segment R0.

[0015] As a further aspect of the present invention: the circular arc segment R0, the two tangent segments L0, the circular arc segment R3, the two circular arc segments R4, and the two perpendicular straight line segments L2 together form a green blank cavity with a rhomboid cross-section.

[0016] The present invention has at least the following beneficial effects:

[0017] (1) The bottom working surface of the upper mold inlay layer and the upper working surface of the punch of the present invention together form a green blank cavity with a cross-section of rhombus in the cavity of the middle mold; the outline of the cross-section of the upper mold inlay layer includes an upper outline, horizontal straight line segments L1 symmetrically distributed on both sides of the upper outline, and a lower outline connecting the two horizontal straight line segments L1. The lower outline does not intersect with the upper outline. When the upper mold inlay layer with this structure is pressed to form a green blank of permanent magnet ferrite tile with a cross-section of rhombus, the magnetic lines of force enter the semi-circular arc R2 interface from the magnetically conductive upper mold matrix. The direction of the magnetic lines of force all points to the center O of the semi-circular arc R2. Under this condition, the N or S poles of the magnetic domains of the slurry particles of the green blank are radially pointing to the same center O, which meets the requirements of magnetic line distribution for pressing rhombus permanent magnet ferrite tile. It does not require improving the performance grade of the raw materials to meet the magnetic characteristic requirements of rhombus permanent magnet ferrite tile.

[0018] (2) The outline of the cross-section of the working surface of the punch of the present invention includes arc segment R3, arc segment R4 and vertical straight line segment L2. The arc segment R0, two tangent segments L0, arc segment R3, two arc segments R4 and two vertical straight line segments L2 together form a green blank cavity with a rhomboid cross-section. With this structure, the two arc segments R4 can form chamfers on both sides of the green blank during pressing, reducing the need for subsequent grinding of the magnetic tile into an arc surface with a tangent shape, and reducing the waste of raw materials caused by large grinding allowance. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a front sectional view of the overall structure of a permanent magnet ferrite tile inlay mold according to the present invention;

[0021] Figure 2 This is a front sectional view of the upper mold structure of the present invention;

[0022] Figure 3 This is a cross-sectional schematic diagram of the rhomboid-shaped green blank cavity formed by the upper die inlay layer and the upper working surface of the punch in this invention;

[0023] Figure 4 This is a schematic diagram of the punch structure of the present invention;

[0024] Figure 5This is a schematic diagram of the magnetic field distribution of a permanent magnet ferrite tile inlay mold according to the present invention.

[0025] In the diagram: 1. Upper mold base; 2. Upper mold insert layer; 3. Middle mold; 4. Punch; 5. Green blank cavity; 6. Magnetic lines of force. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] Please see Figure 1-5 As shown, an embodiment of the present invention discloses a permanent magnet ferrite tile inlay mold, which includes a punch 4 made of magnetic conductive material, a middle mold 3 sleeved outside the punch 4, and an upper mold located directly above the middle mold 3. After the upper mold, punch 4 and middle mold 3 are closed, a green blank cavity 5 for pressing green blanks can be formed.

[0029] The upper mold includes an upper mold base 1 made of magnetic material and an upper mold inlay layer 2 made of non-magnetic material. The bottom of the upper mold base 1 has an upwardly concave upper arc surface. The upper mold inlay layer 2 is fixedly embedded in the upper arc surface. The upper mold inlay layer 2 and the upper mold base 1 form a combination.

[0030] like Figure 1 As shown, after the upper mold, punch 4 and middle mold 3 are closed, the bottom working surface of the upper mold inlay layer 2 and the upper working surface of the punch 4 together form a green blank cavity 5 with a rhomboid cross-section in the cavity of the middle mold 3. The pre-ground slurry is injected into the green blank cavity 5 through the injection hole opened in the middle mold 3, and the green blank of the permanent magnet ferrite tile with a rhomboid cross-section can be formed by pressing it with a hydraulic press.

[0031] Specifically, such as Figure 2As shown, in this embodiment, the outline of the cross-section of the upper mold inlay layer 2 includes an upper outline, horizontal straight line segments L1 symmetrically distributed on both sides of the upper outline, and a lower outline connecting the two horizontal straight line segments L1. The lower outline does not intersect with the upper outline. The upper outline is a semicircular arc R2, which coincides with the cross-sectional outline of the upper arc surface at the bottom of the upper mold base 1. The lower outline includes an arc segment R0 and two tangent segments L0. The arc segment R0 is located directly below the center of the upper outline. The two tangent segments L0 are symmetrically distributed on both sides of the arc segment R0, and both ends of the arc segment R0 are tangently connected to the tangent segments L0 on both sides. The endpoints (a, c) of the two tangent segments L0 furthest from the arc segment R0 are connected to the endpoints of the corresponding horizontal straight line segments L1. The three points of arc vertex b of arc segment R0 and endpoints (a, c) of two tangent segments L0 away from arc segment R0 are located on semicircular arc R1. Semicircular arc R1 and semicircular arc R2 share the same center O.

[0032] With this structure, when the upper mold inlay layer 2 is pressed into a green blank of a permanent magnet ferrite tile with a rhomboid cross-section, the magnetic lines of force 6 enter the semi-circular arc R2 interface from the upper mold substrate 1 of the magnetic conductive material. The direction of the magnetic lines of force 6 is all pointing to the center O of the semi-circular arc R2. Under this condition, the N or S poles of the magnetic domains of the slurry particles of the green blank are all radially pointing to the same center O, which meets the requirements of the distribution of magnetic lines of force 6 for pressing rhomboid permanent magnet ferrite tiles. It can meet the magnetic characteristic requirements of rhomboid permanent magnet ferrite tiles without improving the performance grade of the raw materials.

[0033] Furthermore, such as Figure 3 As shown, in this embodiment, the distance between the arc vertex b of the arc segment R0 and the arc vertex d of the semicircular arc R2 is the thickness T of the upper mold inlay layer 2. The radius R2 of the semicircular arc R2 is equal to the radius R1 of the semicircular arc R1 plus the thickness T of the upper mold inlay layer 2. T is 0-15mm. This prevents the upper arc surface at the bottom of the upper mold base 1 from directly contacting the green blank during the green blank pressing process, and avoids excessive accumulation of magnetic lines 6 at this point, which could easily lead to cracks in the green blank.

[0034] In this embodiment, the included angle of the arc segment R0 is 0°-180°. The included angle is determined based on the corner points of the product required by the customer and in combination with the shrinkage rate of the green blank.

[0035] When manufacturing the permanent magnet ferrite tile inlay mold of the present invention, according to the size of the blank, the vertex b of the arc segment R0 and the endpoints a and c of the two tangent segments L0 away from the arc segment R0 are taken. According to the geometric theorem that three points determine a circle, a semicircular arc R1 is obtained, and the center of the semicircular arc R1 is O. Then, with O as the center and R1+T as the radius, a semicircular arc R2 is obtained. The two points a and c are extended horizontally to the outside to intersect with the semicircular arc R2 to obtain a horizontal straight line segment L1. The closed body formed by the horizontal extension line of the horizontal straight line segment L1 to the outside and the semicircular arc R2 is the upper mold inlay layer 2. The semicircular arc R2 of the upper mold inlay layer 2 matches and fits with the upper arc surface of the upper mold base 1 and is fastened by stainless steel screws to form a combined inlay upper mold.

[0036] The upper mold inlay layer 2, with its arc segment R0 and two tangent segments L0, forms the working surface of the upper mold inlay layer 2. The working surface of the upper mold inlay layer 2 has the same shape as the top surface of the green blank. The working surface of the upper mold inlay layer 2 and the working surface of the punch 4 work together to form a green blank cavity 5 with a rhomboid cross-section in the cavity of the middle mold 3. The arc top thickness of the upper mold inlay layer 2 is T, which avoids the magnetic material of the upper mold base 1 from directly contacting the green blank during green blank forming. Excessive concentration of magnetic lines of force 6 at this point can easily lead to cracks in the green blank. When forming, when the magnetic lines of force 6 enter the semi-circular arc R2 arc interface from the magnetic material upper mold base 1, the direction of the magnetic lines of force 6 all points to the center O of the semi-circular arc R2. Under these conditions, the N or S poles of the magnetic domains of the slurry particles of the green blank are arranged radially towards the same center.

[0037] Example 2

[0038] Combination Figure 3 and Figure 4 As shown, based on Embodiment 1, the outline of the cross-section of the working surface of the punch 4 in this embodiment includes an arc segment R3, an arc segment R4, and a vertical straight line segment L2. The arc segment R3 is located at the center of the cross-section of the working surface of the punch 4. The center of the arc segment R3 and the center O are on the same axis. The two endpoints of the arc segment R3 are respectively connected to an arc segment R4. The endpoints of the arc segment R4 away from the arc segment R3 are connected to a vertical straight line segment L2. The endpoints of the two vertical straight line segments L2 away from the arc segment R4 can be connected to the endpoints (a, c) of the two tangent segments L0 away from the arc segment R0. The specific size of the arc segment R3 and the two arc segments R4 is determined according to the actual product. The specific size of the two arc segments R4 can be set according to the actual chamfering requirements of the product.

[0039] When the endpoints of the two perpendicular straight line segments L2 that are far from the arc segment R4 are connected to the endpoints (a, c) of the two tangent segments L0 that are far from the arc segment R0, the arc segment R0, the two tangent segments L0, the arc segment R3, the two arc segments R4 and the two perpendicular straight line segments L2 together form a green blank cavity 5 with a rhomboid cross-section.

[0040] With this structure, the working surface of the punch 4 has two arc segments R4 that can form chamfers on both sides of the green blank during pressing, reducing the need for subsequent grinding of the magnetic tile into an arc surface with a tangential shape, and reducing the waste of raw materials caused by large grinding allowances.

[0041] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this invention.

[0042] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking," etc., should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0043] The preferred embodiments of the present invention have been described in detail above and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A permanent magnet ferrite tile inlay mold, comprising a punch (4), a middle mold (3) sleeved outside the punch (4), and an upper mold located directly above the middle mold (3), characterized in that... The upper mold includes an upper mold base (1) made of magnetic material and an upper mold inlay layer (2) made of non-magnetic material. The bottom of the upper mold base (1) has an upwardly concave upper arc surface. The upper mold inlay layer (2) is fixedly embedded in the upper arc surface. The bottom working surface of the upper mold inlay layer (2) and the upper working surface of the punch (4) together form a green blank cavity (5) with a rhomboid cross-section in the cavity of the middle mold (3). The outline of the cross section of the upper mold inlay layer (2) includes an upper outline, horizontal straight line segments L1 symmetrically distributed on both sides of the upper outline, and a lower outline connecting the two horizontal straight line segments L1. The lower outline does not intersect with the upper outline. The lower contour line includes an arc segment R0 and two tangent segments L0. The arc segment R0 is located directly below the center of the upper contour line. The two tangent segments L0 are symmetrically distributed on both sides of the arc segment R0, and the two ends of the arc segment R0 are tangent to the tangent segments L0 on both sides respectively. The endpoints (a, c) of the two tangent segments L0 away from the arc segment R0 are respectively connected to the endpoints of the corresponding horizontal straight line segments L1.

2. The permanent magnet ferrite tile inlay mold according to claim 1, characterized in that: The upper contour line is a semi-circular arc R2, which matches the cross-sectional contour line of the bottom upper arc surface of the upper mold base (1).

3. The permanent magnet ferrite tile inlay mold according to claim 2, characterized in that: The three points of the arc vertex b of the arc segment R0 and the endpoints (a, c) of the two tangent segments L0 away from the arc segment R0 are located on the semicircular arc R1. The semicircular arc R1 and the semicircular arc R2 share the same center O.

4. The permanent magnet ferrite tile inlay mold according to claim 3, characterized in that: The distance between the vertex b of the arc segment R0 and the vertex d of the semicircular arc R2 is the thickness T of the upper mold inlay layer (2), and the radius R2 of the semicircular arc R2 is equal to the radius R1 of the semicircular arc R1 plus the thickness T of the upper mold inlay layer (2).

5. A permanent magnet ferrite tile inlay mold according to claim 4, characterized in that: The included angle of the arc segment R0 is 0°-180°.

6. A permanent magnet ferrite tile inlay mold according to any one of claims 1-5, characterized in that: The outline of the cross-section of the working surface of the punch (4) includes an arc segment R3, an arc segment R4 and a vertical straight line segment L2. The arc segment R3 is located at the center of the cross-section of the working surface of the punch (4). The center of the arc segment R3 and the center O are on the same axis. The two endpoints of the arc segment R3 are respectively connected to an arc segment R4. The endpoints of the arc segment R4 away from the arc segment R3 are connected to a vertical straight line segment L2. The endpoints of the two vertical straight line segments L2 away from the arc segment R4 can be connected to the endpoints (a, c) of the two tangent segments L0 away from the arc segment R0.

7. A permanent magnet ferrite tile inlay mold according to claim 6, characterized in that: The circular arc segment R0, the two tangent segments L0, the circular arc segment R3, the two circular arc segments R4, and the two perpendicular straight line segments L2 together form a green blank cavity with a rhomboid cross-section (5).

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