Injection Molding Method for Recoil Starter Pull Disk

Abstract

In order to solve the problems existing in the injection molding method of the recoil starter pull plate in the prior art, such as the inability to ensure the accurate positioning of the electrode plate during the injection molding process and the inability to ensure that the position and size of the contact piece meet the relevant technical requirements after injection molding, the present invention proposes an injection molding method for the recoil starter pull plate, which uses a two-shot injection molding process to inject mold the recoil starter pull plate, including: the first injection molding: using an electrode plate injection molding die to inject mold the electrode plate wrapping layer and form several positioning base points; the second injection molding: using a pull plate injection molding die to inject mold the overall pull plate, and relying on the positioning base points of the electrode plate with the wrapping layer injection molded to achieve accurate positioning. When closing the mold, after the combined pull-out die core is inserted into the set position, the positioning socket at the front end of the combined pull-out die core is just inserted on the outer contact piece, forming the position and size positioning of the outer contact piece of the electrode plate. The beneficial technical effect of the present invention is to first inject mold the wrapping layer on the electrode plate and set several positioning base points, and then perform the overall injection molding of the recoil starter pull plate, effectively ensuring the accurate positioning of the electrode plate during the injection molding process and ensuring that the position and size of the contact piece meet the relevant technical requirements after injection molding.

Description

Technical Field

[0001] The present invention relates to the production technology of the recoil starter pull plate for small or micro gasoline and diesel engines, and particularly relates to an injection molding method for the recoil starter pull plate. Background Art

[0002] The recoil starter pull plate is a key component of small or micro gasoline and diesel engines. Its function is to quickly pull the pull rope wound around the pull plate, so that the flywheel of the gasoline and diesel engine rotates rapidly, thereby driving the engine crankshaft to rotate. For a diesel engine, the rapid rotation of the flywheel makes the compression ratio in the engine cylinder reach the diesel detonation point, thereby realizing the detonation of diesel in the cylinder, and then realizing the normal operation of the diesel engine; for a gasoline engine, the ignition device is turned on while the flywheel rotates rapidly, and then the normal operation of the gasoline engine is realized.

[0003] The outer shape of the recoil starter pull plate is usually a disc shape with a fence or grid structure, so it is called a pull plate. Three electrode plates are arranged in parallel on the outer side of the recoil starter pull plate. The electrode plates are S-shaped and are formed by stamping a phosphor bronze thin sheet. The middle part of the S shape is injection-molded and wrapped in the pull plate body, and the two ends respectively extend out from the inner and outer sides of the pull plate, forming the inner contact piece and the outer contact piece of the electrode plate respectively. And the inner contact piece is welded to the magneto lead wire, and the outer contact piece is inserted and connected to the battery conductive plate (see the attached Figure 1 、 2 and 3. In the figure, B is the recoil starter pull plate, 1 is the electrode plate, 1-1 is the inner contact piece, and 1-2 is the outer contact piece). Since the position and size of the insertion port on the battery conductive plate are fixed, if the position and size error of the outer contact piece are large, it may cause the battery conductive plate not to be inserted into the pull plate, or the electrical contact between the contact pieces is not good after insertion, and accidents may occur therefrom.

[0004] The existing injection molding method for the recoil starter pull plate adopts the method of respectively arranging a positioning groove and a positioning hole at the contact piece of the electrode plate in the injection mold, and then using the injection molding process to wrap the electrode plate and form the pull plate, so as to complete the injection molding of the recoil starter pull plate. Since the electrode plate is S-shaped and is formed by stamping a phosphor bronze thin sheet, it is relatively easy to deform during the injection molding process; and only the two ends of the electrode plate are positioned during the injection molding, which cannot ensure the accurate and reliable positioning of the electrode plate during the injection molding process, and cannot ensure that the position and size of the contact piece after injection molding meet the relevant technical requirements.

[0005] Obviously, the existing injection molding method for the recoil starter pull plate has problems such as inability to ensure the accurate positioning of the electrode plate during the injection molding process and inability to ensure that the position and size of the contact piece after injection molding meet the relevant technical requirements. Summary of the Invention

[0006] To solve the problems existing in the injection molding method of the recoil starter pull plate in the prior art, such as the inability to ensure the accurate positioning of the electrode plate during the injection molding process and the inability to ensure that the position and size of the contact piece after injection molding meet the relevant technical requirements, the present invention proposes an injection molding method for the recoil starter pull plate.

[0007] The injection molding method for the recoil starter pull plate of the present invention uses a two - stage injection molding process to perform injection molding on the recoil starter pull plate, including:

[0008] The first injection: Use the electrode plate injection molding die to perform injection molding on the electrode plate wrapping layer. Specifically, take the contour of the electrode plate when it is placed horizontally as the contour of the cavity of the electrode plate injection molding die, but the size is larger than the contour of the electrode plate; use the inner contact piece and the outer contact piece of the electrode plate as the pressing and fixing points when the upper and lower molds are closed, so that after the upper and lower molds are closed, the entire electrode plate is in a suspended state except at the two contact piece positions; and, at the end of the outer contact piece, there are formed a forming cavity and a long strip rectangular core - pulling structure, so that after injection molding, the end of the outer contact piece of the electrode plate is also formed with a wrapping layer, and a positioning groove with a concave - shaped cross - section is formed on the end face of the wrapping layer; at both ends of the inner side of the middle part of the electrode plate, there are respectively provided forming platforms, so that after injection molding, the wrapping layer on the inner side of the middle part of the electrode plate forms two positioning steps.

[0009] The second injection: Use the pull plate injection molding die to perform the overall injection molding of the pull plate, including inserting the electrode plate with the wrapping layer injection - molded into the set position in the cavity of the pull plate injection molding die; among them, at the position of the pull plate injection molding die cavity corresponding to the inner contact piece of the electrode plate, there is provided a positioning through - hole with a cross - section shape and size matching the cross - section of the inner contact piece; at the position of the pull plate injection molding die cavity corresponding to the positioning groove of the wrapping layer at the end of the outer contact piece of the electrode plate, there is provided a positioning protrusion with a shape and size matching the positioning groove; at the positions of the pull plate injection molding die cavity corresponding to the two positioning steps of the wrapping layer on the inner side of the middle part of the electrode plate, there are respectively provided positioning platforms; at the position of the pull plate injection molding die corresponding to the battery conductive plate, there is provided a combined core - pulling and drawing die core; at the front end of the combined core - pulling and drawing die core corresponding to the outer contact piece, there is provided a contact piece positioning notch, and the contact piece positioning notch constitutes a positioning socket exactly the same as the insertion port of the battery conductive plate; thus, when the electrode plate with the wrapping layer injection - molded is inserted into the cavity of the pull plate injection molding die, the inner contact piece is just inserted into the positioning through - hole, the positioning groove of the wrapping layer at the end of the outer contact piece is just clamped on the positioning protrusion, forming a two - dimensional planar positioning of the electrode plate; at the same time, the two positioning steps on the wrapping layer on the inner side of the middle part of the electrode plate are respectively placed on the positioning platforms, forming a longitudinal positioning of the electrode plate; when the mold is closed, after the combined core - pulling and drawing die core is inserted into the set position, the positioning socket at the front end of the combined core - pulling and drawing die core is just inserted on the outer contact piece, forming the position and size positioning of the outer contact piece of the electrode plate.

[0010] Further, the injection molding of the electrode sheet wrapping layer is carried out by using an electrode sheet injection molding die, including an injection molding process of four parts in one mold; that is, four mold cavities are arranged on a set of molds, and each mold cavity forms an electrode sheet; the four mold cavities are distributed at the four corners of a quadrilateral, and the injection runner is arranged at the geometric center of the quadrilateral.

[0011] Further, the combined pulling die core of the pull plate injection molding die uses a cylinder or a hydraulic cylinder as the power for the forward and backward movement of the combined pulling die core.

[0012] The beneficial technical effect of the injection molding method of the recoil starter pull plate of the present invention is to first injection mold a wrapping layer on the electrode sheet and set a number of positioning base points, and then carry out the overall injection molding of the recoil starter pull plate, which effectively ensures the accurate positioning of the electrode sheet during the injection molding process and ensures that the position and size of the contact piece after injection molding meet the relevant technical requirements. Description of the Drawings

[0013] Attached Figure 1 is a three-dimensional schematic diagram of the recoil starter pull plate;

[0014] Attached Figure 2 is a three-dimensional schematic diagram of the recoil starter pull plate from another angle;

[0015] Attached Figure 3 is a three-dimensional schematic diagram of the electrode sheet;

[0016] Attached Figure 4 is a three-dimensional schematic diagram of the electrode sheet injection molding die of the present invention;

[0017] Attached Figure 5 is a three-dimensional schematic diagram of the electrode sheet wrapping layer of the present invention;

[0018] Attached Figure 6 is a three-dimensional schematic diagram of the electrode sheet wrapping layer from another angle of the present invention;

[0019] Attached Figure 7 is a partial three-dimensional schematic diagram of the pull plate injection molding die of the present invention;

[0020] Attached Figure 8 is a partial three-dimensional schematic diagram of the pull plate injection molding die from another angle of the present invention;

[0021] Attached Figure 9 is a partial three-dimensional schematic diagram of the combined pulling die core of the pull plate injection molding die of the present invention.

[0022] The injection molding method of the recoil starter pull plate of the present invention will be further described below in conjunction with the drawings and specific embodiments. Specific Embodiments

[0023] Attached Figure 4This is a three-dimensional schematic diagram of the injection molding die for the electrode sheet of the present invention, attached Figure 5 This is a three-dimensional schematic diagram of the wrapping layer of the electrode sheet of the present invention, attached Figure 6 This is a three-dimensional schematic diagram of the wrapping layer of the electrode sheet of the present invention from another angle, attached Figure 7 This is a partial three-dimensional schematic diagram of the injection molding die for the pull disc of the present invention, attached Figure 8 This is a partial three-dimensional schematic diagram of the injection molding die for the pull disc of the present invention from another angle, attached Figure 9 This is a partial three-dimensional schematic diagram of the combined pull and draw die core of the injection molding die for the pull disc of the present invention. In the figure, 1 is the electrode sheet, 1-1 is the inner contact piece, 1-2 is the outer contact piece, 1-3 is the positioning groove, 1-4 is the positioning step, 2 is the injection molding die for the electrode sheet, 2-1 is the injection cavity for the electrode sheet, 2-2 is the pressing and fixing point, 2-3 is the long strip rectangular core pulling, 2-4 is the forming platform, 3 is the injection molding die for the pull disc, 3-1 is the positioning through hole, 3-2 is the positioning protrusion, 3-3 is the positioning platform, 3-4 is the combined pull and draw die core, 3-5 is the positioning socket. It can be seen from the figure that the injection molding method for the pull disc of the recoil starter of the present invention uses a two-shot injection molding process to injection mold the pull disc of the recoil starter, including:

[0024] The first injection molding: Use the injection molding die 2 for the electrode sheet to injection mold the wrapping layer of the electrode sheet. Specifically, take the contour of the electrode sheet 1 when it is horizontally placed as the contour of the injection cavity 2-1 of the injection molding die for the electrode sheet, but the size is larger than the contour of the electrode sheet; take the inner contact piece 1-1 and the outer contact piece 1-2 of the electrode sheet as the pressing and fixing points 2-2 when the upper and lower molds are closed, so that after the upper and lower molds are closed, the entire electrode sheet is in a suspended state except at the two contact pieces; and, a forming cavity and a long strip rectangular core pulling 2-3 are provided at the end of the outer contact piece, so that after injection molding, the end of the outer contact piece of the electrode sheet is also formed with a wrapping layer, and a positioning groove 1-3 with a concave cross-section is formed on the end face of the wrapping layer; at both ends of the inner side of the middle part of the electrode sheet, forming platforms 2-4 are respectively provided, so that after injection molding, two positioning steps 1-4 are formed on the wrapping layer of the inner side of the middle part of the electrode sheet;

[0025] Second injection molding: The overall injection molding of the pull plate is carried out using the pull plate injection molding die 3, including inserting the electrode plate with the wrapped layer into the set position in the cavity of the pull plate injection molding die. Among them, at the position of the inner contact piece of the electrode plate corresponding to the cavity of the pull plate injection molding die, a positioning through hole 3-1 with a cross-sectional shape and size matching the cross-section of the inner contact piece is provided; at the position of the positioning groove of the wrapped layer at the end of the outer contact piece of the electrode plate corresponding to the cavity of the pull plate injection molding die, a positioning protrusion 3-2 with a shape and size matching the positioning groove is provided; at the positions of the two positioning steps of the inner wrapped layer in the middle of the electrode plate corresponding to the cavity of the pull plate injection molding die, positioning platforms 3-3 are respectively provided; at the position of the battery conductive plate corresponding to the pull plate injection molding die, a combined pull-out die core 3-4 is provided; at the position of the front end of the combined pull-out die core corresponding to the outer contact piece, a contact piece positioning notch is provided, and the contact piece positioning notch forms a positioning socket 3-5 exactly the same as the insertion port of the battery conductive plate. Thus, when the electrode plate with the wrapped layer is inserted into the cavity of the pull plate injection molding die, the inner contact piece 1-1 is just inserted into the positioning through hole 3-1, and the positioning groove 1-3 of the wrapped layer at the end of the outer contact piece is just clamped on the positioning protrusion 3-2, forming a two-way planar positioning of the electrode plate; at the same time, the two positioning steps 1-4 on the inner wrapped layer in the middle of the electrode plate are respectively placed on the positioning platforms 3-3, forming a longitudinal positioning of the electrode plate; when the mold is closed, after the combined pull-out die core is inserted into the set position, the positioning socket 3-5 at the front end of the combined pull-out die core is just inserted onto the outer contact piece 1-2, forming a position and size positioning of the outer contact piece 1-2 of the electrode plate. The pull plate injection molding method of the recoil starter of the present invention uses the first injection molding to form a wrapped layer around the electrode plate, thereby forming a total of four positioning base points, namely the inner contact piece, the positioning groove and the positioning steps. At the same time, in the pull plate injection molding cavity, a positioning through hole, a positioning protrusion and a positioning platform are respectively provided corresponding to the above four positioning base points; after the electrode plate with the wrapped layer is inserted into the set position in the cavity of the pull plate injection molding die, effective and accurate positioning in three dimensions is obtained. After the mold is closed, the positioning socket simulates the insertion port of the battery conductive plate and is inserted onto the outer contact piece, so that the position and size of the outer contact piece are also effectively and accurately positioned; thus ensuring the accurate positioning of the conductive plate during the injection molding process and ensuring that the position and size of the contact piece after injection molding meet the relevant technical requirements.

[0026] To improve production efficiency, as one of the preferred solutions, the injection molding of the wrapped layer of the electrode plate is carried out using the electrode plate injection molding die, including using an injection molding process of four parts in one mold; that is, four mold cavities are provided on a set of molds, and each mold cavity forms an electrode plate; the four mold cavities are distributed at the four corners of a quadrilateral, and the injection molding runner is arranged at the geometric center of the quadrilateral. Four parts in one mold can effectively improve the injection molding efficiency of the conductive plate and reduce the production cost.

[0027] To ensure the effective operation of the pull-disk injection molding die, as one of the preferred solutions, the combined pull-drawing die core of the pull-disk injection molding die uses a cylinder or a hydraulic cylinder as the power for the forward and backward movement of the combined pull-drawing die core. Using a cylinder or a hydraulic cylinder as the power for the forward and backward movement of the pull-drawing combined die core can ensure the stable and reliable operation of the pull-drawing combined die core while ensuring the position accuracy of the forward and backward movement.

[0028] Obviously, the beneficial technical effects of the pull-disk injection molding method of the recoil starter of the present invention are as follows: first, an injection molding coating layer is formed on the electrode sheet and several positioning base points are set, and then the overall injection molding of the pull-disk of the recoil starter is carried out, effectively ensuring the precise positioning of the electrode sheet during the injection molding process and ensuring that the position and size of the contact piece after injection molding meet the relevant technical requirements.

Claims

1. A method for injection molding a recoil starter pull disc, characterized in that, The recoil starter pulley is injection molded using a two-shot injection molding process, including: The first injection molding: An electrode sheet injection molding die is used to injection mold the electrode sheet wrapping layer. Specifically, the contour of the electrode sheet when placed horizontally is used as the contour of the cavity of the electrode sheet injection molding die, but the size is larger than the contour of the electrode sheet. The inner contact piece and the outer contact piece of the electrode sheet are used as the pressing and fixing points when the upper and lower molds are closed. After the upper and lower molds are closed, the entire electrode sheet is in a suspended state except at the two contact pieces. Moreover, a forming cavity and a long strip rectangular core-pulling are provided at the end of the outer contact piece, so that the end of the outer contact piece of the electrode sheet is also formed with a wrapping layer after injection molding, and a positioning groove with a concave cross-section is formed on the end face of the wrapping layer. Forming platforms are respectively provided at both ends of the inner side of the middle part of the electrode sheet, so that two positioning steps are formed on the wrapping layer of the inner side of the middle part of the electrode sheet after injection molding. The second injection molding: A pulley injection molding die is used to integrally injection mold the pulley, including inserting the electrode sheet injection molded with the wrapping layer into a set position in the cavity of the pulley injection molding die. Among them, at the position of the pulley injection molding die cavity corresponding to the inner contact piece of the electrode sheet, a positioning through hole with a cross-sectional shape and size matching the cross-section of the inner contact piece is provided; at the position of the pulley injection molding die cavity corresponding to the positioning groove of the wrapping layer at the end of the outer contact piece of the electrode sheet, a positioning protrusion with a shape and size matching the positioning groove is provided; at the positions of the pulley injection molding die cavity corresponding to the two positioning steps of the wrapping layer on the inner side of the middle part of the electrode sheet, positioning platforms are respectively provided; at the position of the pulley injection molding die corresponding to the battery conductive plate, a combined pull-out die core is provided; at the position of the front end of the combined pull-out die core corresponding to the outer contact piece, a contact piece positioning notch is provided, and the contact piece positioning notch forms a positioning socket exactly the same as the insertion port of the battery conductive plate. Thus, when the electrode sheet injection molded with the wrapping layer is inserted into the cavity of the pulley injection molding die, the inner contact piece is just inserted into the positioning through hole, and the positioning groove of the wrapping layer at the end of the outer contact piece is just clamped on the positioning protrusion, forming a two-way planar positioning of the electrode sheet; at the same time, the two positioning steps on the wrapping layer of the inner side of the middle part of the electrode sheet are respectively placed on the positioning platforms, forming a longitudinal positioning of the electrode sheet; when the mold is closed, after the combined pull-out die core is inserted into the set position, the positioning socket at the front end of the combined pull-out die core is just inserted onto the outer contact piece, forming a position and size positioning of the outer contact piece of the electrode sheet.

2. The injection molding method of the recoil starter pull disc according to claim 1, characterized in that The injection molding of the electrode sheet wrapping layer using the electrode sheet injection molding die includes using an injection molding process of one mold with four parts; that is, four cavities are provided on a set of molds, and each cavity forms an electrode sheet; the four cavities are distributed at the four corners of a quadrilateral, and the injection runner is arranged at the geometric center of the quadrilateral.

3. The injection molding method of the recoil starter pull disc according to claim 1, characterized in that, The combined pull-out die core of the pulley injection molding die uses a cylinder or a hydraulic cylinder as the power for the forward and backward movement of the combined pull-out die core.

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