Patent Application
20060001192
The present invention relates to a mold part having an insert part inserted therein, specifically to a structure of molded part integrated with plural metallic terminals by way of insert molding and its production method.
It is required to make the thickness of the resin as uniform as possible for making the mold parts in order to prevent the degradation in fluidity and surface property of the resin. However, in case that the mold part has a part having an increased thickness, as this increased thickness part has a larger amount of contraction due to the molding process in comparison with the other part in the mold part, it may cause unfavorable void generation inside such an increased thickness part as has a thickness larger than a designated limitation value. In case of molded parts having an insert part inserted therein, there is such a problem that the contraction of the increased thickness part and the voids generated inside it may make larger the gap developed in the interface between the insert part and the mold part.
In general, there is a method for molding the resin used for the increased thickness part in two-layer structure in order to solve the above described problem. In this method, sub parts having a required size are formed in a preliminary molding process, and then, those pre-mold parts are inserted as insert parts, and finally, those parts are integrated with over-mold parts by way of multiple molding.
In the mold part formed by inserting the insert parts, in the progress of mass production of a wide variety of goods, downsizing and sophisticated configuration of insert part due to higher function ality of parts, there is a limit for increasing the productivity only with a single molding process. In order to solve this problem in the similar manner to the method described above, sub parts are formed in a preliminary molding process, and then, those pre-mold parts are inserted as insert parts, and finally, those parts are integrated with over mold parts by way of multiple molding so that the productivity and the yield rate of the product may be increased. In addition, in terms of higher productivity and low-cost in the molding process, thermoplastic resin is often used as the mold material and an injection molding method is used widely for the molding method in general.
In case of a multiple molding process, a stress due to resin contraction at the over-molding process is applied to the pre-mold part inserted as an insert part, which results in an internal distortion inside the pre-mold part. In addition, heating process for integrating and molding at the over-molding process may give rise to resin contraction of the pre-mold part. This resin contraction mechanism is different from the contraction of the single body of the pre-mold part and depends on the type and shape of the over-mold part, which may result in such a problem as making larger the gap developed in the interface between the insert part and the pre-mold part.
In order to solve the above described problem, there is such a method that an adhesive material such as epoxy resin is coated and harden on the exposed surface of the insert part after the over-molding process in order to seal the interface between the insert part and the pre-mold part, and further fix firmly the insert part and the pre-mold part.
In Japanese Patent Laid-Open No. 7-142817 (1995), there exposed such a method that epoxy resin composed of an adhesive material having a heat hardening property is coated on the insert part for the cover film, and the heat treatment is applied after insert molding process in order to bond the insert part and the insert molding resin.
This pre-mold process is applied to the insert molding of plural metallic terminals as the insert part used for electrical connection.
However, in the same reason as described above, in case of multiple molding process, a stress due to resin contraction at the over-molding process is applied to the pre-mold part inserted as an insert part, which results in an internal distortion inside the pre-mold part. In addition, heating process for integrating and molding at the over-molding process may give rise to resin contraction of the pre-mold part.
This resin contraction mechanism is different from the contraction of the single body of the pre-mold part and depends on the type and shape of the over-mold part. In case of applying the insert molding of plural metallic terminals as the insert part used for electrical connection, this resin contraction may result in such a problem as making larger the gap developed in the interface between the metallic terminal and the pre-mold part.
In the wire-bonding process in the assembly process of the product, as such internal distortion and gap so developed in the molding process disperse and absorb the vibration associated with the bonding process, there may be the possibility leading to the bonding failure.
In order to solve the above described problem, there is such a method that an adhesive material such as epoxy resin is coated and harden on the region of bonding part of the metallic terminal after the over-molding process in order to fix firmly the metallic terminal and the pre-mold part.
As for another solution, the metallic terminal is inserted and pre-molded by using heat-hardening resin, which provides small amount of post-contraction and is less subject to heat history in the over-molding process, for the pre-mold part.
In order to solve the problems due to the increased thickness resin of the mold part inserted as an insert part or to improve the productivity of molding process, there is such a method as sub parts having a required size are formed in a preliminary molding process, and then, those pre-mold parts are inserted as insert parts, and finally, those parts are integrated with over-mold parts by way of multiple molding.
In case of the pre-mold part inserted as a insert part, a stress due to resin contraction at the over-molding process is applied to the pre-mold part inserted as an insert part, which results in an internal distortion inside the pre-mold part. In addition, heating process for integrating and molding at the over-molding process may give rise to resin contraction of the pre-mold part. This resin contraction mechanism is different from the contraction of the single body of the pre-mold part and depends on the type and shape of the over-mold part, which may result in such a problem as making larger the gap developed in the interface between the insert part and the pre-mold part.
In order to solve the above described problem, there is such a method that an adhesive material such as epoxy resin is coated and harden on the exposed surface of the insert part after the over-molding process in order to seal the interface between the insert part and the pre-mold part, and further fix firmly the insert part and the pre-mold part. However, in this method, the coating process of the epoxy resin is required, and the hardening process for hardening and bonding the epoxy resin after the coating process requires the hardening time of 30 to 60 minutes. In addition, it is required to prepare the coating apparatus and the hardening oven, which may lead to lower productivity and higher cost.
As the viscosity of the epoxy resin decreases extremely before hardening and the epoxy resin takes in liquid form, the hardening shape varies widely due to the epoxy resin flowing in an uncured state, which may result in the low reliability in fixing the insert part and the pre-mold part.
As for another method, the metallic terminal is inserted and pre-molded by using heat-hardening resin, which provides small amount of post-contraction and is less subject to heat history in the over-molding process, for the pre-mold part. However, in this method, the material cost for the heat-hardening resin is higher than the thermo setting material, and the reliability of the heat-hardening resin is lower than the reliability of the thermo setting material due to the occurrence of resin flash associated with the heat-hardening resin.
In order to the above described problems, an object of the present invention is to provide a composite mold part by means that low-cost thermo setting resin is used, an insert molding process using an injection molding method advantageously having a higher efficiency in molding process is applied, and the interface between the insert part and the region around the insert part is firmly fixed without forming a gap at the interface between those parts.
Another object of the present invention is to provide an electronic apparatus for increasing the stability in bonding by means of preventing the generation of the gap which disperses and absorbs the vibration for the product (part) formed by wire bonding in the assembly process after molding process.
In order to solve the above problems, the present invention is characterized by a composite mold part formed by forming a pre-mold part by pre-molding an insert part composed of a composite material composed of metal, ceramic, resin or a combination of those materials or one or more metallic terminals used for electrical contact, which is not limited to this example, as the insert part with a pre-mold part composed of thermo plastic resin having crystallinity, and by inserting said pre-mold part into an over-mold part composed of thermo plastic resin and surrounding said pre-mod part with an over-mold part, wherein an insert molding process is applied to an pre-mold part surrounding said pre-mold part to be inserted after applying heat treatment with a temperature lower than a crystalline melting point of said pre-mold part.
It will be appreciated that the composite mold part using the pre-mold part of the present invention can be formed by the insert molding process by using the thermo setting resin and by using the injection mol ding method which is advantageous for the efficient molding process, and that the low-cost production method can provide the composite mold part having a high-reliable insert part which can prevent the occurrence of the gap at the interface between the insert part and the resin surrounding the insert part and the contact between the insert part and the resin surrounding the insert part can be kept.
Now, the problems to be solved by the present invention will be described in detail.
It is required to make the thickness of the resin as uniform as possible for making the mold parts in order to prevent the degradation in fluidity and surface property of the resin. However, in case that the mold part has a part having an increased thickness, as this increased thickness part has a larger amount of contraction due to the molding process in comparison with the other part in the mold part, it may cause unfavorable void generation inside such an increased thickness part as has a thickness larger than a designated limitation value. In case of molded parts having an insert part inserted therein, the contraction of the increased thickness part and the voids generated inside it may result in contributing to make larger the gap developed in the interface between the insert part and the mold part.
In general, there is a method for molding the resin used for the increased thickness part in two-layer structure in order to solve the above described problem, in which sub parts having a required size are formed in a preliminary molding process, and then, those pre-mold parts are inserted as insert parts, and finally, those parts are integrated with over-mold parts by way of multiple molding.
In the mold part formed by inserting the insert parts, in the progress of mass production of a wide variety of goods, downsizing and sophisticated configuration of insert part due to higher functionality of parts, there is a limit for increasing the productivity only with a single molding process, and thus, in order to solve this problem in the similar manner to the method described above, sub parts are formed in a preliminary molding process, and then, those pre-mold parts are inserted as insert parts, and finally, those parts are integrated with over mold parts by way of multiple molding so that the productivity and the yield rate of the product may be increased. In addition, in terms of higher productivity and low-cost in the molding process, thermoplastic resin is often used as the mold material and an injection molding method is used widely for the molding method in general.
A general structure of the mold part having an insert part formed by way of multiple molding process is shown in
In this multiple molding process, the stress due to the resin contraction of the over-mold part 91 is applied to the pre-mold part 93a inserted as the insert part, and the internal distortion occurs inside the pre-mold part 93a. In addition, the heat treatment for integration molding with the over-mold part causes the resin contraction of the pre-mold part 93a, and this resin contraction mechanism is different from the contraction of the single body of the pre-mold part 93 and depends on the type and shape of the over-mold part, which may result in such a problem as making larger the gap 94b developed in the interface between the metallic terminal 92 and the pre-mold part 93a. And furthermore, the gap 94a occurs similarly at the interface between the pre-mold part 93a and the over-mold part 91a.
In order to solve the above described problem, as shown in
However, in this method, the coating process of the epoxy material 99 such as epoxy resin is required, and the hardening process for hardening and bonding the epoxy material 99 such as epoxy resin after the coating process requires the hardening time of 30 to 60 minutes. In addition, it is required to prepare the coating apparatus and the hardening oven, which may lead to lower productivity and higher cost. And furthermore, as the viscosity of the epoxy material 99 decreases extremely before hardening and the epoxy resin takes in liquid form, the hardening shape varies widely due to the epoxy resin flowing in an uncured state, which may result in the low reliability in fixing the electrical bonding part 92a and the pre-mold part 93a.
As for another method, the metallic terminal is inserted and pre-molded by using heat-hardening resin, which provides small amount of post-contraction and is less subject to heat history in the over-molding process, for the pre-mold part. However, in this method, there are such problems that the material cost for the heat-hardening resin is higher than the thermo setting material, and that the reliability of the heat-hardening resin is lower than the reliability of the thermo setting material due to the occurrence of resin flash associated with the heat-hardening resin.
In order to solve the above problems, this embodiment is characterized by a composite mold part formed by forming a pre-mold part by pre-molding an insert part composed of a composite material composed of metal, ceramic, resin or a combination of those materials or one or more metallic terminals used for electrical contact, which is not limited to this example, as the insert part with a pre-mold part composed of thermo plastic resin having crystallinity, and by inserting said pre-mold part into an over-mold part composed of thermo plastic resin and surrounding said pre-mod part with an over-mold part, wherein an insert molding process is applied to an pre-mold part surrounding said pre-mold part to be inserted after applying heat treatment with a temperature lower than a crystalline melting point of said pre-mold part.
One embodiment of the present invention is characterized by that said plural pre-mold parts are inserted simultaneously, and molded together with using the over-mold part.
Another embodiment of the present invention is characterized by that said pre-mold parts are superposed and then inserted simultaneously, and molded together with using the over-mold part.
Yet another embodiment of the present invention is characterized by that said pre-mold part and the over-mold part composed of thermo setting resin having crystallinity are composed of the resin having the common base material and filled with the filler.
Another embodiment of the present invention is characterized by that said pre-mold part and the over-mold part composed of thermo setting resin having crystallinity are composed of the resin having the common base material and filled with the filler, and that the pre-mold part is composed of the resin having the filler filling factor higher than that of the resin used for the over-mold part.
Another embodiment of the present invention is characterized by that said pre-mold part and the over-mold part composed of thermo setting resin having crystallinity are composed of the resin having the common base material and filled with the filler, and that the pre-mold part is composed of the resin having the crystalline melting point higher than that of the resin used for the over-mold part.
Another embodiment of the present invention is characterized by that said pre-mold part and the over-mold part composed of thermo setting resin having crystallinity are composed of the resin having the common base material and filled with the filler, and that the pre-mold part is composed of the resin having the crystalline melting point equivalent to or higher than that of the resin used for the over-mold part, and having the fusibility with the over-mold part.
And furthermore, another embodiment of the present invention is characterized that an electron ic apparatus having an electronic part arranged inside the composite mold part with plural terminals inserted therein used for connecting electrically to outside, in which the composite mold part is composed of the above described configuration.
Embodiments of the present invention will be described in detail by referring to the attached figures. Note that the present invention is not limited to the following embodiments.
The pre-mold part 3 is formed as the metallic terminal 2 configured as plural Cu-based metallic plates with the thickness of 0.6 to 1.00 mm and with the width of 2 to 3 mm on the surface of which metallic deposit is formed with nickel, tin or gold used for electrical connection in order to develop the electrical conjunction and contact property and the corrosion protection property, and those metallic terminals are inserted as the insert part into the pre-mod part 3a composed of the thermo setting resin having crystallinity. In the pre-mold part 3 formed by applying the pre-mold process to the metallic terminal 2 used for electrical connection with the pre-mold part 3a, this embodiment has such a characteristic that heat treatment is applied in advance to the pre-mold part 3a with the temperature lower than the crystalline melting point of the pre-mold part 3a.
As for the material used for the pre-mold part 3a, polyester resin such as polybutylene terphthalate resin (PBT resin), and thermoplastic resin having crystallinity such as polyphenylene sulfide resin (PPS resin), polyamide resin (PA resin), polyacetal resin (POM resin) and polyethylene resin (PE resin) and compound resin formed by filling glass fiber as inorganic material, carbon fiber as organic material, or metallic material into those resin materials can be used.
As for the material used for the over-mold part 1a, in addition to resin materials enable to be used for the pre-mold part, thermoplastic resin having amorphous property such as polycarbonate resin (PC resin), polystyrene resin (PS resin) and ABS resin, thermo setting resin such as epoxy resin and phenol resin, and compound resin formed by filling glass fiber as inorganic material, carbon fiber as organic material, or metallic material into those resin materials can be used.
In the following example, such a material as formed with polybutylene terphthalate resin filled with glass fiber by 40% is used for the material used for both of the pre-mold part 3a and the over-mold part 1a.
So far, the basic structure of the composite mold part 1 is described above, and then the production method in the embodiment shown by
The pre-mold part 3a surrounds continuously the metallic terminals 2 which are formed as plural metallic terminals 2 adjacent to one another, and the electrical connection part 2a of the individual metallic terminal 2 is exposed onto the surface of the pre-mold part 3a made of resin material. As shown in
The condition for heat treatment described above is not limited to this embodiment, but another condition such as the treatment temperature from 130 to 170° C. and the heating time for 1 to 4 hours can contribute to the same and satisfactory performance.
In addition, as for the thickness of the pre-mold part 3a made of resin arranged on the opposite surface of the electrical connection surface, 2 to 3 mm thickness for PBS resin as used in this embodiment provides the best performance, and in contrast, smaller thickness reduces the throughout rigidity of the pre-mold part 3, which results in the distortion and deformation intolerable to the material filling pressure and the resin contraction. On the other hand, larger thickness causes voids generated inside the pre-mold part 3a made of resin, and as this void generation accelerates remarkably the resin expansion and contraction, which leads to making larger the gap in the interface between the metallic terminal 2 and the pre-mold part 3a made of resin.
In the composite mold part 1 formed by inserting the pre-mold part 3 with heat treatment applied and by over-molding process, it will be appreciated that the gap 4 may be developed between the pre-mold part 3a and the over-mold part 21a but there is no gap generated between the metallic terminal 2 and the pre-mold part 3a even when the resin contraction in the over-mold part 1a is developed.
The isometric view of the configuration in which the electronic part 6 is arranged at the designated position inside the composite mold part 1 and the electrical connection part 2a of the metallic terminal 2 and the electronic part 6 are bonded by the aluminum wire 7 is shown in
The shapes of the electrical connection part 2a of the metallic terminal 2 and the pre-mold part 3a so formed as to accelerate the crystallization of the pre-mold part 3a by applying the above described heat treatment to the pre-mold part 3a and contacting firmly the interface between the metallic terminal 2 and the pre-mold part 3a is not limited to the shape shown by the cross-section view illustrated in
Owing to this heat treatment, the internal distortion in the individual pre-mold parts 53 and 63 can be released as well as the crystallization can be accelerated, which leads to the contraction of the pre-mold parts 53 and 63 in the direction so as to fasten the metallic terminals 52 and 62. Therefore, also in the composite mold part 71 formed by over-molding, even if the gaps 74a and 74b might be developed between the pre-mold parts 53a and 63a and the over-mold part 71a, it will be appreciated that there is no gap generated between the metallic terminals 52 and 62 and the pre-mold parts 53a and 63a, which can leads to the establishment of stable bonding performance at the bonding.
The metallic terminals 22 and 32 are configured as plural Cu-based metallic plates with the thickness of 0.6 to 1.0 mm and with the width of 2 to 3 mm on the surface of which metallic deposit is formed with nickel, tin or gold used for electrical connection in order to develop the electrical conjunction and contact property and the corrosion protection property, and those metallic terminals are inserted as the insert part into the pre-mod parts 23a and 23a composed of the thermo setting resin having crystallinity, and then the pre-mold parts 53 and 63 are formed by applying the pre-mold process to the metallic terminals 22 and 32 with the pre-mold parts 23a and 33a. The heat treatment is applied to the individual pre-mold parts 23a and 33a in the high temperature reservoir at 150° C. lower than the crystalline melting point of the pre-mold parts 23a and 33a in about 1 hour, and next, the pre-mold part 33 is overlapped above the pre-mold part 23 as shown in
In this embodiment, by means of decomposing the pre-mold parts for the metallic terminals 22 and 32 formed as the multi stage and for the pre-mold part having larger thickness, it will be appreciated that the pre-mold parts 23a and 33a can be contracted in the direction so as to fasten the metallic terminals 22 and 32, respectively, and the void generation inside the pre-mold part can be prevented.
Owing to this heat treatment, the internal distortion caused during the molding process in the pre-mold parts 23 and 33 can be relaxed as well as the crystallization of the pre-mold part 3aa can be accelerated, and the molecular structure can be stabilized, which leads to the improvement of the rigidity of the pre-mold parts 23a and 33a against the deformation stress after the heat treatment.
Therefore, also in the composite mold part 11 formed by over-molding, even if the gap 14 might be developed between the pre-mold part 23a the over-mold part 11a, it will be appreciated that there is no gap generated between the metallic terminals 52 and 62 and the pre-mold parts 23a and 33a, which can leads to the establishment of stable bonding performance at the bonding.
Though not shown explicitly, the materials used for the pre-mold part and the over-mold part are not limited to those used in this embodiment but can be selected from any combination of resin materials. In the embodiment 1, such a common material as PBT resin composed of heat setting material filled with glass fiber by 40% is used for both of the pre-mold part and the over-mold part. In contrast, in the embodiment 4, glass fiber is filled by 50% in the pre-mold part and glass fiber is filled by 40% in the over-mold part, which provides such resin combination as the filler fraction in the pre-mold part is higher than the filler fraction in the over-mold part.
In the similar manner to the embodiment 1, the metallic terminal is inserted as insert part and molded with the pre-mold part filled with the above described glass fiber by 50%, and then, the heat treatment is applied to the pre-mod part in the high temperature reservoir at 150° C. lower than the crystalline melting point of the pre-mold part, and finally, the pre-mold part completed with the heat treatment is inserted as the insert part, and molded with the over-mold part composed of glass fiber by 40%.
As glass fiber is filled into the resin material for the purpose of increasing the rigidity of resin material, the rigidity of the pre-mold part can be increased by means of making the fraction of glass fiber in the pre-mold higher than the fraction of glass fiber in the over-mold part, and this configuration is effective against the deformation stress by establishing the rigidity and in view of resin contraction behavior of the over-mold part. Thus, higher rigidity in the area of the connection part at the bonding can be established which can leads to stable bonding performance.
In the previous embodiments, such a common material as PBT resin composed of heat setting material is used for both of the pre-mold part and the over-mold part. In contrast, in the embodiment 5, the material used at the pre-mold part is different from the material used at the over-mold part, but those resin materials are filled with filler, and the pre-mold part and the over-mold part are so configured that PPS resin composed of thermo setting resin, having a crystalline melting point higher than the over-mold part, filled with glass fiber by 60% is used for the material of the pre-mod part, and that PBT resin composed of thermo setting resin filled with glass giver by 40% is used for the material of the over-mold part.
In the similar manner to the embodiment 1, the metallic terminal is inserted as insert part and molded with the pre-mold part composed of PPS resin filled with the above described glass fiber by 60%, and then, the heat treatment is applied to the pre-mod part in the high temperature reservoir at 170° C. lower than the crystalline melting point of the pre-mold part, and finally, the pre-mold part completed with the heat treatment is inserted as the insert part, and molded with the over-mold part composed of PBT resin filled with the above described glass fiber by 40%.
As described in the embodiment 4, as the filler fraction of glass fiber in the pre-mold part is higher, it will be appreciated that the rigidity of the pre-mold part is sufficient enough and the resin contraction behavior of the over-mold part is well established and stable bonding performance can be provided, and in addition, as the crystalline melting point of the pre-mold part is higher than the over-mold part, it will be appreciated that the heat effect against the pre-mold part can be reduced when heating and molding the over-mold part.
In the embodiment 6, such a common material as PBT resin composed of heat setting material is used for both of the pre-mold part and the over-mold part, and the pre-mold part and the over-mold part are so configured that resin filled with glass fiber by 50% is used for the pre-mold part and resin filled with glass fiber by 30% is used for the pre-mold part, which provides such resin combination as the filler fraction in the pre-mold part is higher than the filler fraction in the over-mold part, and that the pre-mod part has a crystalline melting point lower than the over-mold part.
In the similar manner to the embodiment 1, the metallic terminal is inserted as insert part and molded with the pre-mold part filled with the above described glass fiber by 50%, and then, the heat treatment is applied to the pre-mod part in the high temperature reservoir at 150° C. lower than the crystalline melting point of the pre-mold part, and finally, the pre-mold part completed with the heat treatment is inserted as the insert part, and molded with the over-mold part composed of glass fiber by 30%.
As the crystalline melting point of the pre-mold part is lower than the over-mold part,
The surface of the pre-mold part due to heating when molding the over-mold part is melted with the micron order thickness, and this melted part is fused with a part of the over-mold part and cooled and solidified. Thus, it will be appreciated that such a composite mold part as there is no gap generated at the interface between the pre-mold part and the over-mold part can be provided. The above described method is effective for the composite mold part which requires the firm contact between the pre-mold part and the over-mold part.
As described also in the embodiment 4, as the filler fraction of glass fiber in the pre-mold part is higher, it will be appreciated that the rigidity of the pre-mold part is sufficient enough and the resin contraction behavior of the over-mold part is well established and stable bonding performance can be provided.
Though the metallic terminal is used as the insert part in the embodiments 1 to 6, the insert part is not limited to this example but any combination of materials is allowed. In the embodiment 7, in order to configure the magnetic circuit by using composite mold parts, the pre-mold part 108 shown in
The pre-mold part 108 is obtained by inserting a couple of magnetic material parts 109a and 109b into a designated position of the die assembly, and by pre-molding those insert parts with pre-mold part 108a composed of PBT resin by means of injection molding method. In addition, in the similar method to that of the embodiment, after molding, heat treatment is applied to the pre-mold part 108 in the high temperature reservoir at 150° C. lower than the crystalline melting point of the pre-mold part 108a in about 1 hour. The pre-mold part 108 with heat treatment applied is inserted as the insert part, and then, the over-mold processing is applied to the insert part with the over-mold part 101a composed of the same material as the pre-mold part 108, and finally the composite mold part 101 can be obtained as the over-mold part.
Owing to this heat treatment, the internal distortion caused during the molding process in the pre-mold part 108aa before heat treatment can be released as well as the crystallization of the pre-mold part 108aa can be accelerated, which leads to the contraction of the pre-mold part 3a in the direction so as to fasten the magnetic material parts 109a and 109b as shown in
The above described embodiments can be applied to the apparatus forming the rotating body such as motors, and to the sensors for sensing the angles, positions and displacement by using the rotating body and for supplying the electric signal, and further applicable to the actuator and drive apparatus having those sensors. For example, those sensors include throttle valves for adjusting the intake air volume and the throttle position sensors mounted onto the throttle valve, the accelerator pedal position sensor for detecting the accelerator opening, and other sensors for forming those sensors and their control structure in the automobile industry. The above embodiment is not limited to the products mentioned above, but can be applied to those products which can resolve the problems to be solved by the present invention.
As the mold part in the above embodiment is configured as described above, it will be appreciate that there is no gap generated at the interface between the insert part and the resin surrounding the insert part and their firm contact can be established, and thus, the following effects can be obtained.
As the internal distortion in the pre-mold part due to the heat treatment can be relaxed as well as the crystallization of the pre-mold part can be accelerated, the dimension of the mold par after heat treatment can be stabilized and the deformation can be reduced, it will be appreciated that the quality and productivity in automation can be increased for the insert part which requires a high precision positioning process.
As for the wire bonding performance extremely subject to the gap between the insert part and the pre-mold part, it will be appreciated that the both parts can be firmly contacted to each other without gap, and hence stable bonding performance can be established without ultrasonic vibration energy dispersion at the bonding process.
As the between the insert part and the resin part can be established in comparison with the conventional insert parts, it will be appreciate that the application to sensors and on-board circuit parts used in the critical environment in which the conventional parts can not be applied can be established.
As the pre-mold part can be obtained by insert molding process using injection molding method which provides advantage in molding efficiency by using the thermo setting resin having crystallinity, it will be appreciate that higher productivity and lower production cost can be established.
As the pre-mold part can be defined in advance by the mold die assembly, it will be appreciated that the resin parts having an effective shape in order to increase the contact between the insert-part and the resin part surrounding the insert part can be arranged with a high degree of accuracy, and that the pre-mold part can be designed relatively freely without constraint applied to the quality, shape, arrangement and numbers of the insert parts to be inserted into the die assembly.
According to the present invention, it will be appreciated that the electronic parts are arranged on the mold or inside the mold, and the mold part for the electronic apparatus can be realized by providing the electric signal exchange with outside.
The above described embodiments can be applied to the apparatus forming the rotating body such as motors, and to the sensors for sensing the angles, positions and displacement by using the rotating body and for supplying the electric signal, and further applicable to the actuator and drive apparatus having those sensors.
Although the present invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omission and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodied within a scope encompassed and equivalent thereof with respect to the feature set out in the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-196197 | Jul 2004 | JP | national |
