CN113790254B - Plastic gear and mold opening method thereof - Google Patents
Plastic gear and mold opening method thereof Download PDFInfo
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- CN113790254B CN113790254B CN202110962780.8A CN202110962780A CN113790254B CN 113790254 B CN113790254 B CN 113790254B CN 202110962780 A CN202110962780 A CN 202110962780A CN 113790254 B CN113790254 B CN 113790254B
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- gear
- mold
- tooth
- pressing block
- plastic gear
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/08—Profiling
- F16H55/088—Profiling with corrections on tip or foot of the teeth, e.g. addendum relief for better approach contact
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/17—Toothed wheels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/08—Profiling
- F16H2055/086—Silent gear profiles
Abstract
The invention discloses a plastic gear and a die opening method thereof, and relates to the technical field of gear design, wherein the plastic gear comprises a gear ring and gear teeth arranged along the circumferential direction of the gear ring, the gear ring is used for being installed on a screw, the tooth direction of the gear teeth is provided with a drum shape, and the length of the drum shape is 5-10 microns. The plastic gear replaces a metal gear and can solve the problems of corrosion resistance and light weight, drum-shaped amount is designed on the gear teeth of the plastic gear, the meshing contact area of two gear teeth is reduced, and the two gear teeth are meshed better, so that the purposes of reducing noise and improving efficiency are achieved.
Description
Technical Field
The invention relates to the technical field of gear design, in particular to a plastic gear and a mold opening method thereof.
Background
With the development of a miniature gear transmission system, the plastic gear gradually replaces a hardware gear with the advantages of low cost, high molding efficiency and the like, and is widely applied. However, the plastic gear has lower strength than metal, and after installation and loading, the plastic gear mostly has a position deflection phenomenon, so that the edge of the end surface is easy to contact and engage, and engagement impact can be caused in the transmission process of the gear box body, so that noise is caused due to unstable transmission.
Disclosure of Invention
1. Technical problem to be solved by the invention
The invention provides a plastic gear and a die opening method thereof, aiming at the technical problem that the plastic gear is easy to cause end surface edge contact meshing, so that the two gears are meshed better, and the aims of reducing noise and improving efficiency are fulfilled.
2. Technical scheme
In order to solve the problems, the technical scheme provided by the invention is as follows: the utility model provides a plastic gear, includes ring gear and the teeth of a cogwheel that sets up along ring gear circumference, the ring gear is used for installing on the screw rod, the tooth of the teeth of a cogwheel is equipped with cydariform volume to the direction, the length of cydariform volume is 5 ~ 10 um.
Optionally, the root digging and shape modifying formula of the gear tooth is as follows:
wherein: h represents the root height, d represents the pitch diameter, dbRepresents the diameter of the gear base circle, and y is the rack displacement.
Optionally, the formula for trimming the edge of the gear tooth is as follows:
wherein: d represents the reference circle diameter, h represents the effective tooth crest height, and y is the rack displacement.
The invention also discloses a die opening method after the plastic gear is injection molded, which comprises the following steps:
(1) after injection molding is finished, the front mold is fixed, the rear mold moves towards the direction far away from the front mold under the driving of the driving piece, the sliding block assembly and the pressing block assembly on the rear mold clamp the iron piece, the iron piece moves towards the direction far away from the front mold, and then the plastic gear on the iron piece is separated from the front mold, and in the separation process, the plastic gear drives the mold core and the bearing to rotate;
(2) after the rear die moves in place, the sliding block assembly loosens the iron piece, the pressing block assembly loosens the iron piece, and the plastic gear demolding is completed.
Optionally, the mold core has an inverse drum shape matched with the drum shape of the gear teeth, and the inverse drum shape is obtained by discharging the electrode.
Optionally, the processing technology of the electrode is as follows: the method comprises the steps of firstly calculating the modification of the tooth shape and the tooth direction of an electrode through finite element analysis and three-dimensional modeling, and then transmitting data to a precision machine tool through a three-dimensional digital analog for processing.
Optionally, the slider assembly includes a first slider and a second slider, and both the first slider and the second slider are slidably connected to the rear mold.
Optionally, the pressing block assembly includes a first pressing block and a second pressing block, the first pressing block is disposed on the inner side of the first sliding block, and the second pressing block is disposed on the inner side of the second sliding block.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:
(1) the plastic gear that this application embodiment provided, the metal gear can be solved in the plastic gear replacement, and corrosion-resistant and lightweight problem reduces the meshing area of contact of two teeth of a cogwheel at the design cydariform volume of the teeth of a cogwheel of plastic gear, makes two teeth of a cogwheel meshing better to reach the purpose that noise abatement raises the efficiency. When the crown amount is less than 5um, the crown positions of two teeth are not yet contacted with each other with a gap at the inherent center distance, and if the center distance is corrected to be contacted with the crown, the tooth top is contacted with the tooth root of the corresponding tooth, and noise and vibration are generated during operation. When more than 10um, two drum-shaped positions extrude each other after the assembly is completed, and the gear can be clamped and hung when being started.
(2) According to the plastic gear provided by the embodiment of the application, when the gear teeth of the plastic gear are rotationally released from the mold core, the drum-shaped position on the gear teeth only passes through the demolding distance with the length of one tooth height, and the drum shape cannot deform under the rotation action.
Drawings
Fig. 1 is a schematic structural diagram of a plastic gear according to an embodiment of the present invention.
Fig. 2 is a schematic view of a mold opening structure of a plastic gear according to an embodiment of the present invention.
The figures are numbered: 1. a ring gear; 2. gear teeth; 21. tooth top; 22. a tooth root; 23. the tooth direction; 3. a front mold; 31. molding kernels; 32. a bearing; 4. a rear mold; 41. a first slider; 42. a second slider; 43. a first pressing block; 44. and a second pressing block.
Detailed Description
For a further understanding of the present invention, reference will now be made in detail to the embodiments illustrated in the drawings.
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and are not to be construed as limiting the invention. It should be noted that, for the convenience of description, only the portions related to the present invention are shown in the drawings. The terms first, second, and the like in the present invention are provided for convenience of describing the technical solution of the present invention, have no specific limiting function, are all general terms, and do not constitute a limiting function on the technical solution of the present invention. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "connected" are intended to be construed broadly, as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. Those skilled in the art can understand the specific meaning of the above terms in the present invention in specific cases. The technical solutions in the same embodiment and the technical solutions in different embodiments can be arranged and combined to form a new technical solution without contradiction or conflict, and both are within the scope of the present invention.
Example 1
Combine attached figure 1-2, the plastic gear of this embodiment includes ring gear 1 and the teeth of a cogwheel 2 that sets up along 1 circumference of ring gear, ring gear 1 is used for installing on the screw rod, the tooth of the teeth of a cogwheel 2 is equipped with the cydariform volume to 23 directions, the length of cydariform volume is 5 ~ 10 um. The plastic gear replaces a metal gear to solve the problems of corrosion resistance and light weight, the drum-shaped amount is designed at the gear teeth 2 of the plastic gear, the meshing contact area of the two gear teeth 2 is reduced, the two gear teeth 2 are meshed better, and therefore the purposes of reducing noise and improving efficiency are achieved. When the crown amount is less than 5um, the crown positions of the two teeth 2 are not yet in contact with each other with a gap therebetween at the inherent center distance, and if the center distance is corrected to be in contact with the crown, the tooth tip 21 may contact the tooth root 22 of the corresponding tooth 2, and noise and vibration may be generated during operation. When the diameter is larger than 10um, the two drum-shaped positions are mutually extruded after the assembly is finished, and the gear teeth 2 are clamped when being started.
Example 2
With reference to fig. 1-2, compared with the technical solution of embodiment 1, the plastic gear of this embodiment can be improved as follows: the root digging and shape modifying formula of the gear teeth 2 is as follows:
wherein: h represents the tooth root 22 height, d represents the pitch circle diameter, db represents the gear base circle diameter, and y is the rack displacement.
Example 3
With reference to fig. 1-2, compared with the technical solution of embodiment 1 or 2, the plastic gear of this embodiment can be improved as follows: the trimming formula of the gear teeth 2 is as follows:
wherein: d represents the diameter of the indexing circle, h represents the effective tooth top 21 height, and y is the rack displacement.
The problems are solved and the technical effects are as follows: when the drum shape is designed, the tooth top 21 of the gear tooth 2 requires edge trimming and the tooth bottom 22 requires root digging, so that the formed drum shape is beneficial to reducing noise in plastic gear transmission and improving the stability of the plastic gear transmission.
Example 4
With reference to fig. 1-2, the mold opening method for the plastic gear after injection molding of the embodiment includes the following steps:
(1) after the injection molding is finished, the front mold 3 is fixed, the rear mold 4 moves towards the direction far away from the front mold 3 under the driving of the driving piece, the sliding block assembly and the pressing block assembly on the rear mold 4 clamp the iron piece, so that the iron piece moves towards the direction far away from the front mold 3, further, the plastic gear on the iron piece is separated from the front mold 3, and in the separation process, the plastic gear drives the mold core 31 and the bearing 32 to rotate;
(2) after the rear die 4 moves in place, the sliding block assembly loosens the iron piece, the pressing block assembly loosens the iron piece, and the plastic gear demolding is completed.
The mold core 31 is used for casting the plastic gear, the bearing 32 is arranged on the periphery of the mold core 31, the mold core 31 and the bearing 32 can rotate relative to the front mold 3, when the gear teeth 2 of the plastic gear are rotated and removed from the mold core 31, the drum-shaped position on the gear teeth 2 only passes through a demolding distance with the length of one tooth height, and the drum shape is ensured not to deform under the rotation action.
Example 5
With reference to fig. 1-2, compared with any of the technical solutions of embodiments 1-4, the mold opening method of the present embodiment can be improved as follows: in the mold opening method, the mold core 31 has a reverse drum shape matched with the drum shape of the gear teeth 2, and the reverse drum shape is obtained by discharging electrodes.
Example 6
With reference to fig. 1-2, compared with any of the technical solutions of embodiments 1-5, the mold opening method of the present embodiment can be improved as follows: the processing technology of the electrode comprises the following steps: the method comprises the steps of firstly calculating the modification of the tooth shape and the tooth direction of an electrode through finite element analysis and three-dimensional modeling, and then transmitting data to a precision machine tool through a three-dimensional digital analog for processing.
Example 7
With reference to fig. 1-2, compared with any of the technical solutions of embodiments 1-6, the mold opening method of the present embodiment can be improved as follows: the slide block assembly comprises a first slide block 41 and a second slide block 42, and the first slide block 41 and the second slide block 42 are both connected with the rear mold 4 in a sliding mode. The first slider 41 and the second slider are used to grip the iron member when the rear mold 4 is moved, and the first slider 41 and the second slider 42 are movable in directions away from each other when the rear mold 4 is moved in place.
Example 8
With reference to fig. 1-2, compared with any of the technical solutions of embodiments 1-7, the mold opening method of the present embodiment can be improved as follows: the pressing block assembly comprises a first pressing block 43 and a second pressing block 44, wherein the first pressing block 43 is arranged on the inner side of the first sliding block 41, and the second pressing block 44 is arranged on the inner side of the second sliding block 42. Because the diameters of the iron pieces are different in thickness, the thicker part of the iron piece is clamped by the first sliding block 41 and the second sliding block 42, and the thinner part of the iron piece is clamped by the first pressing block 43 and the second pressing block 44, so that the stability of the iron piece in the moving process of the rear die 4 is improved.
Example 9
With reference to fig. 1-2, compared with any of the technical solutions of embodiments 1-8, the plastic gear of the present embodiment can be improved as follows:
example 10
With reference to fig. 1-2, compared with any of the technical solutions of embodiments 1-9, the plastic gear of this embodiment can be improved as follows:
the present invention and its embodiments have been described above schematically, without limitation, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching, without departing from the spirit of the invention, the person skilled in the art shall not inventively design the similar structural modes and embodiments to the technical solution, but shall fall within the scope of the invention.
Claims (5)
1. The utility model provides a die sinking method after plastic gear injection moulding, its characterized in that, plastic gear includes the ring gear and follows the teeth of a cogwheel that ring gear circumference set up, the ring gear is used for installing on the screw rod, the tooth direction of the teeth of a cogwheel is equipped with the cydariform volume, the length of cydariform volume is 5 ~ 10um, the root digging modification formula of the teeth of a cogwheel is:
wherein: dFRepresenting root circle diameter, h representing root height, d representing pitch circle diameter, dbRepresents the diameter of a gear base circle, and y represents the displacement of the rack; alpha represents the pressure angle, hfFBRRepresenting the height of a tooth root, wherein the trimming formula of the gear tooth is as follows:
wherein: dTRepresenting toothThe diameter of the starting point of top modification, d represents the diameter of a reference circle, h represents the effective tooth crest height, y is the displacement of the rack, haTBRRepresenting the tooth crest shape height;
the plastic gear mold opening method comprises the following steps:
(1) after the injection molding is finished, the front mold is fixed, the rear mold moves towards the direction far away from the front mold under the driving of the driving piece, the sliding block assembly and the pressing block assembly on the rear mold clamp the iron piece, so that the iron piece moves towards the direction far away from the front mold, and further the plastic gear on the iron piece is separated from the front mold, and the plastic gear drives the mold core and the bearing to rotate in the separation process;
(2) after the rear die moves in place, the sliding block assembly loosens the iron piece, the pressing block assembly loosens the iron piece, and the plastic gear demolding is completed.
2. The method of opening a mold according to claim 1, wherein the mold core has an inverse crown corresponding to a crown of the gear teeth, the inverse crown being obtained by discharging the electrode.
3. Mould opening method according to claim 2, characterised in that the electrode machining process is as follows: the method comprises the steps of firstly calculating the modification of the tooth shape and the tooth direction of an electrode through finite element analysis and three-dimensional modeling, and then transmitting data to a precision machine tool through a three-dimensional digital analog for processing.
4. The method of opening a mold of claim 1, wherein the slide assembly includes a first slide and a second slide, each of the first slide and the second slide being slidably coupled to the rear mold.
5. The mold opening method of claim 1, wherein the pressing block assembly includes a first pressing block and a second pressing block, the first pressing block is disposed inside the first slide block, and the second pressing block is disposed inside the second slide block.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110962780.8A CN113790254B (en) | 2021-08-20 | 2021-08-20 | Plastic gear and mold opening method thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110962780.8A CN113790254B (en) | 2021-08-20 | 2021-08-20 | Plastic gear and mold opening method thereof |
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| Publication Number | Publication Date |
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| CN113790254A CN113790254A (en) | 2021-12-14 |
| CN113790254B true CN113790254B (en) | 2022-06-21 |
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Citations (6)
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| CN1337328A (en) * | 2000-08-05 | 2002-02-27 | 郧阳汽车齿轮总厂 | Timing gear ofr automobile engine |
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| CN203906710U (en) * | 2014-02-19 | 2014-10-29 | 泰州市宏祥动力机械有限公司 | Environment-friendly type silent gear |
| CN105500630A (en) * | 2016-02-24 | 2016-04-20 | 厦门精卫模具有限公司 | Die capable of injection molding plastic part with outer thread and bevel gear |
| CN106704543A (en) * | 2016-12-05 | 2017-05-24 | 贵州群建精密机械有限公司 | Method for reducing noise of engine by shaping timing gear of engine |
| CN111283923A (en) * | 2020-02-13 | 2020-06-16 | 河南科技大学 | Method for shaping and processing plastic cement tooth-direction drum-shaped gear |
-
2021
- 2021-08-20 CN CN202110962780.8A patent/CN113790254B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1337328A (en) * | 2000-08-05 | 2002-02-27 | 郧阳汽车齿轮总厂 | Timing gear ofr automobile engine |
| CN1614526A (en) * | 2004-11-18 | 2005-05-11 | 华中科技大学 | Method for profiling involute straight teeth conical gear |
| CN203906710U (en) * | 2014-02-19 | 2014-10-29 | 泰州市宏祥动力机械有限公司 | Environment-friendly type silent gear |
| CN105500630A (en) * | 2016-02-24 | 2016-04-20 | 厦门精卫模具有限公司 | Die capable of injection molding plastic part with outer thread and bevel gear |
| CN106704543A (en) * | 2016-12-05 | 2017-05-24 | 贵州群建精密机械有限公司 | Method for reducing noise of engine by shaping timing gear of engine |
| CN111283923A (en) * | 2020-02-13 | 2020-06-16 | 河南科技大学 | Method for shaping and processing plastic cement tooth-direction drum-shaped gear |
Non-Patent Citations (1)
| Title |
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| 齿轮泵齿轮注塑模设计与制造;夏翔等;《塑料》;20181018(第05期);第100-102页 * |
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