Injection mold for retainer machining

Abstract

The utility model relates to the technical field of retainer production, in particular to an injection mold for retainer processing. Comprising a mold body, the mold body comprises a fixed mold plate and a movable mold plate, a mold cavity plate is arranged at the bottom of the fixed mold plate, a mold cavity is formed in the mold cavity plate, a mold core is arranged in the mold cavity, a base is fixed to the bottom of the mold core, the base is located on the movable mold plate, a ring is arranged on the periphery of the mold core, and the ring is connected with the mold cavity; a plurality of sub-runners communicated with the mold cavity are uniformly distributed at the top of the mold core, and are provided with detachable connecting closure pieces. The injection mold provided by the utility model can be used for adjusting the flow of the sub-runner, and a new runner does not need to be reprocessed, so that the injection mold is beneficial to improving the working efficiency, reducing the research and development cost and improving the product quality.

Description

Technical Field

[0001] The utility model relates to the technical field of cage production, in particular to an injection mold for cage processing. Background Art

[0002] Cages are bearing cages, also known as bearing retainers, and are bearing parts that partially wrap all or part of the rolling elements and move with them. They are used to isolate the rolling elements and usually guide the rolling elements and keep them in the bearings. Plastic cages are widely used because they can be formed by one-time injection molding, can obtain precise geometric shapes and dimensional accuracy, and have low surface roughness values, do not require mechanical processing, and have high production efficiency.

[0003] Injection molds are mostly used in the production process of plastic cages. Injection molds are tools that inject, hold pressure, and cool molten plastic under the action of an injection molding machine to obtain plastic products with precise dimensions and certain mechanical properties. For plastic products with complex product structures and high quality requirements, reasonable injection mold runners are designed through software analysis (such as Moldflow software) combined with industry experience. The size and distance of the runners directly determine the quality of plastic products.

[0004] For newly made injection molds, when the design of the runner cannot meet the quality requirements of plastic products, the design of the runner of the dynamic mold needs to be changed, which has high R&D costs and a long cycle; when the mold is put into production and the number of products produced reaches a certain level, when the runners and gates inside the mold are worn, the speed of the plastic melt in the runners will also change, causing abnormal product quality. At this time, new runners need to be remade and processed, resulting in low production efficiency.

[0005] In order to solve the above problems, an injection mold is provided which can adjust the flow rate of the plastic melt in the branch channel. Utility Model Content

[0006] The utility model aims to provide an injection mold for processing a retainer, which can adjust the flow of a branch flow channel without reprocessing a new flow channel, thereby helping to improve work efficiency, reduce research and development costs, and improve product quality.

[0007] The utility model provides an injection mold for processing a retainer, comprising a mold body, the mold body comprising a fixed mold plate and a movable mold plate, a cavity plate is provided at the bottom of the fixed mold plate, a cavity is provided on the cavity plate, a core is provided in the cavity, a base is fixed at the bottom of the core, the base is located on the movable mold plate, a ring is provided on the outer periphery of the core, and the ring is connected to the cavity;

[0008] A plurality of flow diversion channels connected with the cavity are evenly distributed on the top of the core, and a detachable connecting and shut-off member is provided on the flow diversion channels.

[0009] Furthermore, the connecting cut-off member includes a plurality of cut-off blocks with different cut-off amounts, and the cut-off blocks are provided with cut-off grooves corresponding to the diversion channel; the cut-off grooves include a first channel located in the middle area and a second channel located at both ends, the cross-sectional dimensions of the second channel are the same as the cross-sectional dimensions of the diversion channel, and the cross-sectional dimensions of the first channel of each cut-off block are different.

[0010] Furthermore, the connecting cut-off member includes two cut-off blocks, namely a first cut-off block and a second cut-off block, the cross-sectional size of the first channel of the first cut-off block is consistent with the cross-sectional size of the branch channel, and the ratio of the cross-sectional size of the first channel of the second cut-off block to the cross-sectional size of the first channel of the first cut-off block is 4:5.

[0011] Furthermore, the connection between the first channel and the second channel of the second intercepting block is a rounded structure.

[0012] Furthermore, a mounting groove is provided on the top of the core, and the intercepting block is connected to the mounting groove by bolts.

[0013] Furthermore, a static positioning boss is provided between two adjacent flow diversion channels, a static hole is provided at the bottom of the cavity plate, and the static positioning boss can be inserted into the static hole.

[0014] Furthermore, the ring is connected to the cavity by screws; a plurality of overflow wells are arranged on the ring, and one overflow well is correspondingly arranged in the middle area of ​​two adjacent branch channels.

[0015] Furthermore, a venting groove is provided on a side wall of the overflow well away from the core.

[0016] Furthermore, six branch channels connected to the cavity are evenly distributed on the top of the core, and two opposite branch channels are located on the same diameter of the core.

[0017] Furthermore, the outer peripheral surface of the core is evenly provided with 23 molding grooves corresponding to the support beams of the retaining frame.

[0018] In summary, the utility model has the following advantages:

[0019] The injection mold provided by the technical solution of the utility model is suitable for a retainer with 23 window holes. According to the characteristics of the retainer with 23 window holes, multiple evenly distributed branch channels are designed on the core, which can reduce the number of welding marks of the product and reduce the raw material loss of the material handle; by arranging a detachable connecting cut-off piece on the branch channel, the flow of the plastic melt on the branch channel can be quickly adjusted. When the design of the flow channel cannot meet the product quality requirements or the branch channel and the gate are worn, the flow adjustment on the branch channel can be achieved without re-processing a new flow channel. It is more convenient and quick to use, which helps to improve product quality, improve production efficiency and reduce R&D costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 This is a main sectional view of the injection mold in the embodiment of the utility model;

[0022] Figure 2 It is a structural schematic diagram of a 23-window hole retainer in the prior art;

[0023] Figure 3 It is a schematic diagram of the structure of the core, the ring and the push ring in the embodiment of the utility model;

[0024] Figure 4 It is a top view of the core, the ring and the push ring in the embodiment of the utility model;

[0025] Figure 5 A schematic diagram showing the comparative structures of two types of interception blocks in an embodiment of the utility model;

[0026] Figure 6 A top view of the ring in the embodiment of the utility model;

[0027] Figure 7 The mechanical performance index of the raw material of the cage in the embodiment of the utility model;

[0028] Figure 8 This is a warpage analysis diagram of the small end of the cage processed using the first cut-off block in this embodiment;

[0029] Fig. 9 This is a warping analysis diagram of the big end of the cage processed using the first cut-off block in this embodiment;

[0030] Fig.10This is a warpage analysis diagram of the small end of the cage processed after the cut-off block is replaced in this embodiment;

[0031] Fig.11 This is a warping analysis diagram of the large end of the cage processed after the cut-off block is replaced in this embodiment;

[0032] Fig.12 This is the distribution diagram of the welding marks of the retaining frame after replacing the cut-off block in this embodiment.

[0033] Description of reference numerals: 1-fixed template; 101-fixing bolt; 2-movable template; 3-cavity plate; 301-cavity; 4-core; 401-shunt channel; 402-connecting intercepting member; 402a-first intercepting block; 402b-second intercepting block; 4021-first bolt; 4022-second bolt; 403-ring; 4031-overflow well; 4032-exhaust groove; 404-static positioning boss; 405-base; 406-first channel; 407-second channel; 5-push ring; 6-retaining frame; 601-top ring; 602-window hole; 603-support beam; 604-bottom ring; 7-support plate; 8-bottom plate; 801-support bolt; 9-ejector plate; 901-center top; 10-ejector sleeve; 11-cold material well; 12-needle valve hot runner; 13-heat insulation board; 14-spring; 15-water channel. DETAILED DESCRIPTION

[0034] The technical solution of the utility model will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0037] Example

[0038] An injection mold for processing a cage, such as Figure 1 As shown, the mold body includes a fixed mold plate 1 and a movable mold plate 2. The bottom of the fixed mold plate 1 is connected to a cavity plate 3 through a fixing bolt 101. The cavity plate 3 is provided with a cavity 301. The cavity 301 is provided with a core 4. The bottom of the core 4 is fixed with a base 405. The base 405 is located on the movable mold plate 2. The outer periphery of the core 4 is provided with a ring 403. The ring 403 is fixed to the cavity plate 3 by screws. The ring 403 is the molding part of the outer diameter of the large end of the retainer, which generally adopts full circumference exhaust. The base 405 cooperates with the ejection system, and the ejection system includes an ejector sleeve 10, a push ring 5, a center ejector 901, an ejection plate 9 and a spring 14.

[0039] The mold body also includes a pouring system and a cooling system. The pouring system consists of a needle valve hot runner 12, a cold material well 11, a diverter 401 and a gate. The cooling system includes a water channel 15 (cavity water channel and core water channel). The needle valve hot runner 12 is assembled with the fixed mold plate 1 through a cylindrical surface. The gate bushing is locked on the fixed mold plate 1 with four screws. The cavity plate 3 and the fixed mold plate 1 are installed with four fixing bolts 101. The cavity 301 and the cavity bottom 302 are positioned with three locating pins and then integrated with the cavity plate 3 through a special-shaped support surface and locked with screws. Finally, the ring 403 and the cavity 301 are locked with support screws to form the fixed mold plate 1; the assembly method of the movable mold plate 2 is as follows: the ejector sleeve 10 Through the cooperation between the cylindrical surfaces, it is placed in the center of the core 4. The core 4 is positioned by 3 pins and installed on the base 405, and then screwed together on the dynamic template 2. The push ring 5 is matched with the core 4 in a clearance and installed on the push ring reset rod. The center top 901 and the push ring reset rod are installed on the ejection plate 9. Through the cooperation of the center top 901 and the ejector sleeve 10, an ejection system is formed. The support plate 7 and the bottom plate 8 are assembled and locked together on the dynamic template 2 through 4 support bolts 801. The top of the fixed template 1 and the bottom of the bottom plate 8 are respectively fixed with heat insulation plates 13.

[0040] The mold body of the utility model adopts the injection mold in the prior art, wherein the pouring system, cooling system, ejection system and assembly of the movable mold plate and the fixed mold plate of the mold body are all prior art. The utility model improves the core 4 on the basis of the mold body in the prior art, and the improvements are as follows: (1) 6 evenly distributed diversion channels 401 are evenly arranged on the top of the core 4, and a detachable connecting cut-off member 402 is arranged on the diversion channel 401; (2) a static positioning boss 404 is arranged on the top of the core 4; (3) an overflow well 4031 is arranged on the ring 403; Figure 3 and Figure 4 As shown, the specific technical solution is as follows:

[0041] The injection mold in this embodiment is suitable for the holder 6 of 23 window holes in the prior art, such as Figure 2 As shown, it includes a top ring 601, a bottom ring 604, and a plurality of support beams 603 evenly distributed along the circumference between the top ring 601 and the bottom ring 604, and a window hole 602 for mounting a rolling element is formed between adjacent support beams 603; the top ring 601 and the bottom ring 604 are equivalent to the small end and the large end of the cage mentioned below. The material of the processing cage 6 is reinforced polyamide (nylon 66 + 30% glass fiber), and its mechanical performance parameters are as follows Figure 7As shown. In view of the characteristics of the 23-window retainer, the number of gates cannot be divided evenly when designing. Referring to the flow ratio of the raw materials, the number of gates for this product is designed to be 6, and the number of runners is also designed to be 6. The purpose of this design is to reduce the number of weld marks of the product (weld marks are the weak point of the entire product) and reduce the loss of raw materials in the material handle (this product does not allow the addition of recycled materials) under the condition of a reasonable flow ratio. Reducing the loss of raw materials can increase the added value of this product. The gate size is designed to be an equilateral trapezoidal straight gate with a short side of 3mm, a long side of 5mm, and a height of 2.5mm. The runner size is consistent with the gate, that is, an equilateral trapezoidal runner with a short side of 3mm, a long side of 5mm, and a height of 2.5mm.

[0042] The connecting intercepting member 402 in this embodiment includes a plurality of intercepting blocks with different intercepting amounts, and the intercepting blocks are provided with intercepting grooves connected with the diverter channel 401. The intercepting grooves are composed of a first channel 406 located in the middle area and a second channel 407 located at both ends, and the second channel 407 is aligned with the diverter channel 401 and has the same cross-sectional size. The cross-sectional size of the first channel 406 of each intercepting block is different (except for the cross-sectional size, the other dimensions are the same). By changing the cross-sectional size of the first channel 406, a plurality of intercepting blocks with different intercepting amounts are designed to adjust the flow of the plastic melt on the diverter channel 401.

[0043] In this embodiment, two types of cut-off blocks are provided for the 23 window hole retainer, such as Figure 5 As shown, the first intercepting block 402a and the second intercepting block 402b are respectively, the cross-sectional size of the first channel 406 of the first intercepting block 402a is the same as the cross-sectional size of the diverter 401, when the first intercepting block 402a is used, the flow rate of the plastic melt on the diverter 401 will not change. The ratio of the cross-sectional size of the first channel 406 of the second intercepting block 402b to the cross-sectional size of the second channel 407 of the first intercepting block 402a is 4:5 (that is, the cross-sectional size is designed to be an equilateral trapezoid with a short side of 2.4mm, a long side of 4mm, and a height of 2mm, which is narrowed by 80% according to each size of an equilateral trapezoid with a short side of 3mm, a long side of 5mm, and a height of 2.5mm). When the second intercepting block 402b is used, when the plastic melt on the diverter 401 passes through the second intercepting block 402b, the flow rate is reduced by 20% compared with the use of the first intercepting block 402a.

[0044] In this embodiment, the length of the second channel 407 of the intercepting block is 20% of the length of the entire diverter channel 401; the connection between the first channel 406 and the second channel 407 of the second intercepting block 402b is a rounded structure, which uses a rounded transition to avoid sharp corners. The two ends of the intercepting block and the diverter channel 401 are spliced ​​with a matching gap of 0.06mm, which can ensure that no flash is generated and prevent cold materials from occurring during the production process.

[0045] like Figure 3 and Figure 4 As shown, a mounting groove is provided on the flow divider 401, and the intercepting block is fixed in the mounting groove. The intercepting block is provided with a first bolt 4021 and a second bolt 4022, and the first bolt 4021 passes through the intercepting block and is fixed to the bottom wall of the mounting groove. An arc hole is provided on the side edge of the intercepting block, and an arc hole is also provided on the top of the core 4. The two arc holes form a complete bolt hole, and the second bolt 4022 is located in the bolt hole.

[0046] like Figure 3 and Figure 4 As shown, six static positioning bosses 404 are provided on the top of the core 4, a static positioning boss 404 is provided in the middle area of ​​two adjacent diversion channels 401, and six static holes corresponding to the static positioning bosses 404 are provided on the bottom of the cavity plate 3. The static positioning bosses 404 can be inserted into the static holes to make the mold fit accurately and appropriately reduce the static positioning hardness, thereby avoiding strain on the core 4 and the cavity 301 during the production process.

[0047] When the core 4 provided in this embodiment is used, the first intercepting blocks 402a can be installed on all six branch channels 401, and then one or more of the first intercepting blocks 402a can be replaced by the second intercepting blocks 402b according to software analysis or actual production needs.

[0048] Practical Application

[0049] In view of the characteristics of the 23-window retainer, the utility model adopts the first cut-off block at the beginning of production. Through multiple analyses of Moldflow software, such as Figure 8-11 As shown in the figure, when one of the first cut-off blocks is replaced by the second cut-off block, the warping deformation of the small end of the cage is 0.1113-0.3016mm, the overall difference is greatly reduced, and the warping deformation is relatively distributed; at the same time, the maximum warping deformation of the large end of the cage is also reduced from 0.5532mm to 0.4595mm, and the warping deformation is evenly distributed without generating large support points. By using a second cut-off block, the warping deformation of the product can be greatly reduced, thereby ensuring the dimensional stability of the cage and increasing its service life.

[0050] During the use of the cage, the window hole and the window beam are always subjected to a force due to the dynamic load of the roller. Due to the structural design of the cage, different weld marks will be formed at the small end and the large end of the product during the injection molding process. The weld mark refers to the intersection and fusion of two melts. Since it is mainly the force between molecules rather than the effect of chemical bonds, the mechanical properties of the cage at the weld mark are often greatly reduced. To test the strength of the weld marks at the large and small ends of the cage, according to Appendix D of EN 12080:2017+A1:2022(E), appropriate tooling can be made, installed on a mechanical testing machine, and the force value can be obtained according to the appropriate test plan. In order to ensure a good welding effect at the weld mark, during the injection molding process, at a high mold temperature, ensure that the front air is discharged cleanly and the front melt temperature is appropriate; under the appropriate injection pressure of the injection molding machine and the high holding pressure, the melt at the weld mark is sufficiently dense after combination. At the same time, the mechanical properties of the weld mark are also related to its confluence angle. When the angle is less than 135°, a suture line is generated, and when it is greater than 135°, a fusion line is generated. For this cage made of glass fiber reinforced polyamide, when the confluence angle is less than 135°, fewer molecules cross the fusion line to fuse with each other, and the glass fiber is usually parallel to the suture line and cannot cross the suture line, thus losing the reinforcement effect.

[0051] The cage is analyzed by Moldflow to make the weld mark at the small end of the cage have a good welding effect, and the confluence angle is increased by selecting a suitable cut-off block. When the second cut-off block with a 20% flow reduction is used as above, the analysis results are as follows Fig.12 As shown, the convergence angle of the weld mark at the small end of the retainer on the left side of the diverter channel of the second cut-off block is greater than 135°, thereby greatly improving the mechanical properties of this weld mark; and at the same time, the convergence angles of other points can be changed.

[0052] For the weld mark at the large end of the retainer, according to the Moldflow analysis results, an overflow well 4031 can be set on the ring 403 of the core 4 at a certain distance away from the weld mark, thereby increasing its convergence angle. Figure 6 As shown, in this embodiment, 6 overflow wells 4031 are provided, and one overflow well 4031 is provided between two adjacent runners 401. At the same time, a 0.08 mm deep exhaust groove 4032 is provided on the side wall of the overflow well 4031 away from the core 4 to increase the exhaust effect of the weld mark, improve the mechanical properties of the retainer and improve the appearance of the weld mark.

[0053] The injection mold provided by the utility model is suitable for the production and processing of a retainer with 23 window holes. A detachable connecting shut-off piece and a plurality of shut-off blocks of different sizes are arranged on the runner, so that the flow rate of the plastic melt on the runner can be quickly adjusted, thereby changing the feed amount of the corresponding gate, adjusting the warping deformation of the product, and optimizing the product size; when the mechanical properties of the product are affected by the unreasonable angle of the weld mark, the shut-off blocks with different shut-off amounts can be replaced to change the plastic melt flow rate in the runner, increase the welding angle, and improve its mechanical properties; during the production process, when the product is deformed due to the loss of the mold runner or the gate, there is no need to reprocess the runner, and only different shut-off blocks need to be replaced, thereby avoiding affecting the supply cycle, reducing the mold maintenance cost, and improving production efficiency.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. An injection mold for processing a retainer, comprising a mold body, wherein the mold body comprises a fixed mold plate (1) and a movable mold plate (2), characterized in that: A cavity plate (3) is provided at the bottom of the fixed mold plate (1), a cavity (301) is provided on the cavity plate (3), a core (4) is provided in the cavity (301), a base (405) is fixed at the bottom of the core (4), the base (405) is located on the movable mold plate (2), a ring (403) is provided on the outer periphery of the core (4), and the ring (403) is connected to the cavity (301); A plurality of flow diversion channels (401) communicating with the mold cavity (301) are evenly distributed on the top of the mold core (4), and a detachable connecting shut-off member (402) is provided on the flow diversion channels (401).

2. The injection mold according to claim 1, characterized in that: The connecting intercepting member (402) comprises a plurality of intercepting blocks with different intercepting amounts, and the intercepting blocks are provided with intercepting grooves connected to the diverting channel (401); the intercepting grooves comprise a first channel (406) located in the middle area and second channels (407) located at both ends, the cross-sectional dimensions of the second channel (407) are the same as the cross-sectional dimensions of the diverting channel (401), and the cross-sectional dimensions of the first channel (406) of each intercepting block are different.

3. The injection mold according to claim 2, characterized in that: The connecting shut-off member (402) comprises two shut-off blocks, namely a first shut-off block (402a) and a second shut-off block (402b); the cross-sectional size of the first channel (406) of the first shut-off block (402a) is consistent with the cross-sectional size of the branch channel (401); the ratio of the cross-sectional size of the first channel (406) of the second shut-off block (402b) to the cross-sectional size of the first channel (406) of the first shut-off block (402a) is 4:

5.

4. The injection mold according to claim 3, characterized in that: The connection between the first channel (406) and the second channel (407) of the second intercepting block (402b) is a rounded structure.

5. The injection mold according to claim 2, characterized in that: A mounting groove is provided on the top of the core (4), and the intercepting block is connected to the mounting groove via bolts.

6. The injection mold according to claim 1, characterized in that: A static positioning boss (404) is provided between two adjacent flow diversion channels (401), a static hole is provided at the bottom of the cavity plate (3), and the static positioning boss (404) can be inserted into the static hole.

7. The injection mold according to claim 1, characterized in that: The ring (403) is connected to the cavity (301) by means of screws; a plurality of overflow wells (4031) are provided on the ring (403), and one overflow well (4031) is correspondingly provided in the middle area of ​​two adjacent flow diversion channels (401).

8. The injection mold according to claim 7, characterized in that: An exhaust groove (4032) is provided on the side wall of the overflow well (4031) away from the core (4).

9. The injection mold according to claim 1, characterized in that: Six branch channels (401) communicating with the mold cavity (301) are evenly distributed on the top of the mold core (4), and two opposite branch channels (401) are located on the same diameter of the mold core (4).

10. The injection mold according to claim 1, characterized in that: The outer peripheral surface of the core (4) is evenly provided with 23 molding grooves corresponding to the support beams of the retaining frame.

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