CN214499745U - Output shaft assembly with injection molding bearing and motor applying output shaft assembly - Google Patents

Abstract

The utility model discloses an output shaft assembly with an injection molding bearing and a motor applying the output shaft assembly, which comprises an output shaft, an injection molding bearing and an injection molding gear, wherein the injection molding bearing and the injection molding gear are sleeved on the output shaft, and the injection molding bearing is positioned at the upper end of the injection molding gear; the injection molding bearing and the injection molding gear are integrally molded to form an injection molding body, and the output shaft assembly is formed by insert injection molding of the output shaft in an injection molding body mold. The utility model discloses well gear of moulding plastics and the integrative moulding plastics of bearing of moulding plastics have reduced the fit-up gap between assembly process and part, and radial clearance obtains improving, has solved the bearing pine of moulding plastics that exists at present and has taken off the problem. In addition, the output shaft assembly is formed by insert injection molding of the output shaft in an injection body mold, so that a mechanism for protecting broken teeth in the motor is formed, the mechanical strength of the output shaft assembly can be ensured, the stability of the sliding friction torque of the motor is greatly improved, the product assembly process is simplified, and the cost is reduced.

Description

Output shaft assembly with injection molding bearing and motor applying output shaft assembly

Technical Field

The utility model relates to the technical field of electric machine, especially, relate to a take output shaft assembly of bearing of moulding plastics and use motor of this output shaft assembly.

Background

The general stepping motor mainly comprises a machine shell assembly, a rotor, a stator assembly, an upper polar plate fixing plate assembly, an injection molding body box, an output shaft assembly and a cover plate assembly, wherein the rotor assembly is installed on a middle shaft of the machine shell, the stator assembly is installed inside the machine shell, the upper polar plate fixing plate assembly is installed on the stator assembly, the injection molding body box and the output shaft assembly are installed on the upper polar plate fixing plate assembly, and the cover plate assembly is installed on the machine shell assembly and riveted and fixed with each other.

In the prior art, when an output shaft, a friction gasket and a spring gasket are riveted by a stepping motor, the riveting machine axially presses the friction gasket, the part positioned on the radial outer side is pressed towards the other side through a deformation part, the deformation part and an injection molding body step form linear elastic contact through generated deformation, static friction is generated, the output shaft assembly with the friction mechanism is widely used for protecting an injection molding body structure in the stepping motor, and the friction gasket, the spring gasket and the friction gasket share riveting pressure and then have static friction with the injection molding body, so that the friction gasket, the spring gasket and the injection molding body are kept to idle under instant stress of the injection molding body, the transmission of power is blocked, and the purpose of protecting the injection molding body is achieved. However, this structure has the following problems:

1. after the motor stress protection mechanism works for too many times, the situation that the sliding friction torque is unstable (durability) exists, so that the motor load stress standard is reduced until the motor fails, and the torque performance of the motor is influenced.

2. The output shaft assembly leads to the output shaft to slightly deform under the axial acting force of riveting pressure in the riveting process, the injection molding body can circumferentially expand outwards after being compressed and deformed under bidirectional axial pressure, and the output shaft and the framework boss positioning hole are axially bent to be assembled with the rest speed reduction injection molding bodies of the motor after being engaged and clamped with fixed points due to the deformation of parts in the output shaft assembly, so that mechanical loss is generated, and the performance of the motor is influenced.

3. The whole output assembly has more parts, complex assembly process and high cost.

In order to solve the above problems, in the prior art, there is provided a method for directly injection molding an output shaft and an injection molded body to form a slip mechanism between the output shaft and the injection molded body, as disclosed in CN2486784Y, but after the output shaft and the injection molded body are injection molded to form the slip mechanism, there are still many problems in meeting the requirements of friction force and stability.

In addition, when the output shaft and the cover plate are installed, an injection molding bearing needs to be assembled between the cover plate and the output shaft, the process is complex, the assembly clearance is increased, the radial clearance of an output shaft assembly is enlarged, the gear engagement is jammed, and the noise of the motor is poor.

SUMMERY OF THE UTILITY MODEL

In order to solve among the prior art output shaft assembly process complicacy among the prior art, the bearing of moulding plastics breaks away from easily, and takes place the technical problem of disconnected tooth because of the instantaneous atress of gear easily, the utility model provides an output shaft assembly of bearing of moulding plastics and the motor of using this output shaft assembly solve above-mentioned problem.

The utility model provides an output shaft assembly with an injection molding bearing, which comprises an output shaft, an injection molding bearing and an injection molding gear, wherein the injection molding bearing and the injection molding gear are sleeved on the output shaft, and the injection molding bearing is positioned at the upper end of the injection molding gear; the injection molding bearing and the injection molding gear are integrally molded to form an injection molding body, and the output shaft assembly is formed by insert injection molding of the output shaft in an injection molding body mold.

Furthermore, a first shoulder is arranged on a shaft section of the output shaft, which is in contact with the injection molding bearing, and the ratio of the radial thickness D of the injection molding bearing to the diameter D0 of the first shoulder is 1/10-11/10.

Furthermore, a second shoulder is arranged on a shaft section of the output shaft, which is in contact with the gear, and the ratio of the radial thickness H6 of the injection molding gear to the diameter H7 of the second shoulder is 3/10-9/4.

Preferably, the number of the second shoulder is one or more than one.

Preferably, the output shaft is made of metal.

Preferably, the surface of the output shaft is treated by nickel plating.

Further, the output shaft includes first shaft section, fourth shaft section, second shaft section and the third shaft section that meets in proper order along the axial, the fourth shaft section is located the circumference of the bearing of moulding plastics is inboard, the second shaft section is located the circumference of the gear of moulding plastics is inboard, first shaft section and third shaft section are located respectively the both ends of injection moulding body, first convex shoulder is located the fourth shaft section, the second convex shoulder is located on the second shaft section.

Furthermore, a single-flat or double-flat structure is arranged at one end, far away from the fourth shaft section, of the first shaft section.

Further, a first annular groove is formed between the first shoulder and the first shaft section.

Further, a second annular groove is formed between the second shoulder and the fourth shaft section.

Further, the axial height H2 of the second annular groove is greater than or equal to 0.5mm, and the radial depth H3 of the second annular groove is less than or equal to 1 mm.

Further, the axial height H0 of the first annular groove is greater than or equal to 0.5mm, and the radial depth H1 of the first annular groove is less than or equal to 1 mm.

Furthermore, the one end of keeping away from the second axle section on the third shaft section is provided with the spindle nose step, the diameter H8 of spindle nose step is 1.4 ~ 1.8 mm.

Furthermore, one end of the third shaft section, which is connected with the second shaft section, is provided with a flat milling step, and the diameter of the flat milling step is larger than that of the shaft head step.

Furthermore, the lower end face of the injection molding body is provided with an annular convex rib.

Furthermore, the lower end face of the injection molding body is provided with a sinking step which is sunken upwards, and the injection molding pouring gate is positioned in the sinking step.

Preferably, the injection molding body is injection molded by POM materials.

The utility model also provides a motor, which comprises a casing component, a rotor, a stator component and a gear set, wherein the rotor, the stator component and the gear set are positioned in the casing component; the gear set comprises a plurality of stages of single gears which are in meshed transmission and the output shaft assembly with the injection molding bearing, and the output shaft assembly is positioned at the last stage of the gear set.

Furthermore, the casing subassembly includes casing and apron, the output shaft subassembly passes through the apron stretches out the casing subassembly, be equipped with two mounting holes on the apron, the center of output shaft subassembly and two the center of mounting hole is not on same straight line.

The utility model has the advantages that:

(1) output shaft subassembly, distinguish and have the current bearing of moulding plastics and the riveting of end cover after again with the assembly of output shaft subassembly, the gear of moulding plastics and the integrative moulding plastics of bearing of moulding plastics have reduced the fit-up gap between assembly process and part, radial clearance obtains improving, has solved the bearing of moulding plastics pine that exists at present and has taken off the problem. In addition, the output shaft assembly is formed by insert injection molding of the output shaft in an injection body mold, and friction force and occlusion force are generated between the output shaft and an injection body through insert injection molding, so that the mechanism for protecting broken teeth in the motor is formed, the mechanical strength of the output shaft assembly can be ensured, the stability of the sliding friction torque of the motor is greatly improved, the product assembly process is simplified, and the cost is reduced.

(2) Take output shaft subassembly of bearing of moulding plastics and applied this output shaft subassembly's motor, with the gear contact of moulding plastics be equipped with the second convex shoulder on the shaft section of output shaft, through reasonable control the radial thickness H6 of the gear of moulding plastics with the diameter H7's of second convex shoulder proportional relation guarantees on the basis of output shaft intensity, makes the interlock between output shaft and the injection molding body more evenly balanced, the output shaft subassembly after the hot injection shaping the static friction and the stability (durability) of kinetic friction moment tend to the superiority.

(3) Take output shaft assembly of bearing of moulding plastics and use motor of this output shaft assembly, the lower terminal surface of the injection molding body is provided with cyclic annular protruding muscle, reduce all the other gears in the gear train with the utility model discloses the area of contact of the injection molding body makes the injection molding body reduce rather than the frictional force on other gear surfaces, has reduced mechanical loss.

Drawings

The present invention will be further explained with reference to the drawings and examples.

FIG. 1(a) is a perspective view of an embodiment of an output shaft assembly according to the present invention;

fig. 1(b) is an exploded view of an output shaft assembly according to the present invention;

FIG. 2 is a schematic view of the output shaft as it is being injection molded in an injection mold;

FIG. 3 is a schematic diagram of the gripping force and friction between the output shaft and the injection molded body after the output shaft assembly is injection molded;

FIG. 4(a) is a schematic cross-sectional view of the output shaft assembly with only one second annular groove provided;

FIG. 4(b) is a cross-sectional schematic view of the output shaft assembly (the diameter of the second shoulder is greater than the diameter of the second shoulder in FIG. 4(a))

FIG. 4(c) is a cross-sectional schematic view of the output shaft assembly without the second shoulder;

FIG. 5 is a graph of static and dynamic friction moments versus number of operations for the three output shaft assemblies of FIGS. 4(a), 4(b), and 4 (c);

FIG. 6 is a table of high temperature test sliding friction analysis data for various samples with three surface treatments of nickel plating, blackening and phosphating;

FIG. 7 is a table of high temperature test stiction analysis data for various samples under three surface treatments of nickel plating, blackening, and phosphating;

FIG. 8 is a table of data from low temperature test sliding friction analysis of various samples with three surface treatments of nickel plating, blackening and phosphating;

FIG. 9 is a table of cryogenically tested stiction analysis data for a plurality of samples under three surface treatments of nickel plating, blackening and phosphating;

FIG. 10 is a table of cold and hot stamping test sliding friction analysis data for various samples with both nickel and black plating surface treatments;

FIG. 11 is a table of cold and hot stamping test stiction analysis data for various samples with both nickel and black plating;

FIG. 12 is a table of data from a friction durability test sliding friction analysis of various samples with three surface treatments of nickel plating, blackening and phosphating;

FIG. 13 is a chart of stiction durability test stiction analysis data for a plurality of samples under three surface treatments of nickel plating, blackening and phosphating;

fig. 14 is a schematic cross-sectional view of the output shaft assembly of the present invention (the first shaft section is provided with a single flat structure);

FIG. 15(a) is a schematic cross-sectional view of the output shaft assembly with two second annular grooves;

FIG. 15(b) is a schematic cross-sectional view of the output shaft assembly with three second annular grooves provided;

FIG. 16 is a sizing view of a third shaft segment of the output shaft assembly shown in FIG. 1 (a);

FIG. 17 is a schematic view showing the fitting relationship between the steps of the shaft head and the flanging hole of the fixing plate;

FIG. 18 is an enlarged view at N of FIG. 17;

FIG. 19 is a schematic view of the injection molded article according to the present invention;

fig. 20 is an exploded view of the motor of the present invention;

fig. 21 is a schematic structural view of the gear unit according to the present invention;

fig. 22 is a side view of the motor of the present invention;

fig. 23 is a front view of the motor of the present invention;

fig. 24 is a schematic view of a prior art output shaft assembly when tilted.

In the figure, 1, an output shaft assembly, 101, an output shaft, 1011 a first shaft section, 1012, a second shaft section, 10121, a second shoulder, 10122, a second annular groove, 1013, a third shaft section, 10131, a shaft head step, 10132, a milled flat step, 1014, a fourth shaft section, 10141, a first shoulder, 10142, a first annular groove, 102, an injection molding body, 1021, an injection molding bearing, 1022, an injection molding gear, 10221, an annular convex rib, 10222, a sunken step, 2, a near runner wall, 3, an injection molding body mold, 4, a cavity core layer, 5, a fixing plate flanging hole, 6, a fixing plate flanging boss, 7, an injection molding sprue, 8, a rotor, 9, a stator assembly, 10, a gear set, 11, a housing, 12, a cover plate, a mounting hole, 13, an upper pole plate fixing plate, 14, a middle shaft, 15, a single gear, 16, a motor wiring harness, 1a, an output shaft assembly, 1021a bearing, 1022a, an output gear, 17 a, And assembling the clearance.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

Example one

As shown in fig. 1(a) -4 (a), an output shaft assembly includes an output shaft 101, an injection molding bearing 1021 sleeved on the output shaft 101, and an injection molding gear 1022, wherein the injection molding bearing 1021 is located at an upper end of the injection molding gear 1022; the injection bearing 1021 and the injection gear 1022 are integrally formed into an injection molding body 102 in an injection molding mode, and the output shaft assembly 1 is formed by insert injection molding of the output shaft 101 in the injection molding body mold 3.

As shown in fig. 24, which is an assembly diagram of an output shaft assembly 1a in the prior art, since the bearing 1021a is riveted with the cover plate 12 and then assembled with the output shaft assembly 1a, an assembly gap 17 exists between the bearing 1021a and the output shaft assembly 1a, and the output shaft assembly 1a tilts due to the radial play of the output shaft assembly 1a caused by the existence of the assembly gap 17, and in addition, since a gasket needs to be installed between the bearing 1021a and the output gear 1022a, the axial size of the output gear 1022a is reduced, the area of the meshing part of the output gear 1022a is correspondingly reduced, and the output shaft assembly 1a tilts more easily. The utility model discloses an integrative injection moulding of bearing 1021 and the gear 1022 of moulding plastics has higher uniformity after moulding plastics, has reduced one assembly process, has reduced the part fit-up gap, and radial clearance obtains improving, has solved the bearing 1021 problem of droing of moulding plastics that exists at present, and the while technology process reduces, cost optimization.

Preferably, the injection-molded body 102 is located at a position below the axial middle of the output shaft 101. The lower extreme of output shaft 101 is the location end, and the nearer the location end, the smaller is the offset distance in radial direction of output shaft subassembly 1, and output shaft subassembly 1 radially rocks after the location and reduces and makes and the meshing of the rest gear of motor better, has both guaranteed gear discontinuous tooth intensity, has also avoided the jam phenomenon that takes place between other rest gears in gear 1022 and the motor of moulding plastics, has reduced mechanical loss and has restrained abnormal sound phenomenon.

Additionally, the utility model discloses an inserts makes output shaft 101 and injection molding body 102 become the mechanism of the disconnected tooth of protection in the motor of moulding plastics, can guarantee output shaft subassembly 1's mechanical strength simultaneously, increases enterprise competitiveness.

The principle of the output shaft assembly 1 for realizing the broken tooth protection is introduced as follows: as shown in fig. 2, an output shaft 101 is placed in an injection molding body mold 3, after an insert of the output shaft 101 is hot injected into a plastic part, since the friction coefficient of the outer surface of the output shaft 101 is high after lathing, the melt of the near-flow passage wall 2 in the injection mold has a temperature difference with the injection molding body mold 3 and a cooling speed is high, so that the viscosity of the melt of the near-flow passage wall 2 is increased, the flow rate of the melt in a cavity core layer 4 is far higher than that of a surface layer, the melt is subjected to a shear stress effect between the inner layer and the inner layer, orientation is generated along the flow direction, a certain friction force and a certain biting force are formed between the injection molding body 102 and the output shaft 101 after injection molding, the output shaft 101 can be fixed in the injection molding body 102, the output shaft and the injection molding body 102 cannot rotate radially, and the torque performance of the output shaft assembly 1 is less affected by the number of work. When the output shaft 101 is stressed instantaneously, the instantaneous impact force overcomes the friction force and the biting force between the output shaft 101 and the injection molding body 102, so that the output shaft 101 and the injection molding body 102 slip, and the phenomenon of tooth breakage of other gears 15 in the gear set 10 is avoided. In addition, the consistency between the parts of the output shaft 101 after the insert injection molding process is high. As shown in fig. 3, after the output shaft 101 is insert molded, when the plastic is hot injected into the injection mold 3, it forms a circumferential wrap with the output shaft 101 (i.e. the melt wraps around the fourth shaft section 1014 and the second shaft section 1012 of the output shaft 101), so as to generate a biting force and a frictional force on the contact surface of the injection molded body 102 and the output shaft 101, where F in fig. 3 denotes the biting force and the frictional force.

Preferably, a second shoulder 10121 is arranged on a shaft section of the output shaft 101 which is in contact with the injection gear 1022, and the ratio of the radial thickness H6 of the injection gear 1022 to the diameter H7 of the second shoulder 10121 is 3/10-9/4.

The second shoulder 10121 can reasonably increase the distance from the radially farthest point of the output shaft 101 to the center line of the output shaft 101, so that the contact area between the output shaft 101 and plastic is increased, and the radial rotation resistance (static friction) is improved. On the basis of ensuring the strength of the output shaft assembly 1, the design enables the engagement force between the output shaft 101 and the injection molding body 102 to be more uniform and balanced, and the stability (durability) of the static friction force and the dynamic friction torque of the output shaft assembly 1 after hot injection molding tends to be superior.

The ratio of the radial thickness H6 of the injection gear 1022 to the diameter H7 of the second shoulder 10121 needs to be reasonably controlled, fig. 5 is static friction torque and dynamic friction torque tests performed on the three output shaft 101 structures of fig. 4(a), 4(b) and 4(c), and it can be seen from fig. 5 that the strength of the output shaft assembly 1 is the lowest under the condition that the second shoulder 10121 is not provided, that is, the static friction torque (c) and the dynamic friction torque (c1) of the output shaft assembly 1 corresponding to fig. 4(c) are the lowest, and the torque performance is rapidly reduced along with the increase of the working times; the strength of the output shaft assembly 1 provided with the second shoulder 10121 is significantly greater than that of the output shaft assembly 1 not provided with the second shoulder 10121, that is, the static friction moments (a and b) of the output shaft assembly 1 corresponding to fig. 4(a) and 4(b) are greater than the static friction moment (c) of the output shaft assembly 1 corresponding to fig. 4(c), and the dynamic friction moments (a1 and b1) of the output shaft assembly 1 corresponding to fig. 4(a) and 4(b) are greater than the dynamic friction moment (c1) of the output shaft assembly 1 corresponding to fig. 4 (c); if the diameter of the second shoulder 10121 is too large, the strength of the output shaft assembly 1 is rather reduced, and the static friction moment (a) and the dynamic friction moment (a1) of the output shaft assembly 1 corresponding to fig. 4(a) are greater than the static friction moment (b) and the dynamic friction moment (b1) of the output shaft assembly 1 corresponding to fig. 4 (b).

The reasons for this phenomenon are: in the case of a limited outer diameter H4 of the injection-molded gearwheel 1022 (due to limited gearbox space), if the diameter H7 of the second shoulder 10121 is too large, the radial projection thereof in the injection-molded body 102 will be too large, and the plasticized plastic material will be injected hot because of the small contact surface stroke formed by the radial projection, so that it cannot flow back completely due to the high surface tension of the output shaft 101. The second shoulder 10121 of the output shaft 101 is as symmetrical as possible while ensuring a uniform and thick wall thickness, further increasing the ability of the output shaft 101 to resist radial rotation (static friction) and the sliding friction with the plastic member. When the diameter H7 of the second shoulder 10121 is too small, the output shaft 101 is complicated to machine and has reduced strength.

Preferably, the general thickness H5 of the injection gear 1022 is 3.75-4.75mm, and in this case, the injection gear 1022 has a larger holding force to the output shaft 101, so that the friction force is more stable and the durability is better. In this embodiment, the thickness H5 of the injection molded gear 1022 is 3.75 mm.

Similarly, a first shoulder 10141 is arranged on a shaft section of the output shaft which is in contact with the injection bearing 1021, and the ratio of the radial thickness D of the injection bearing 1021 to the diameter D0 of the first shoulder 10141 is 1/10-11/10, which is caused by: in order to be reasonably assembled with the flanging hole of the fixing plate, the radial thickness D of the injection molding bearing 1021 cannot be too thin, poor injection molding such as material shortage cracking and stress shrinkage deformation can be caused due to the too thin radial thickness D, and if the radial thickness D of the injection molding bearing 1021 is too thick, the outer diameter of an output shaft inside an injection molding body is too small, and the strength is not enough.

The first shoulder 10141 and the second shoulder 10121 may be provided in one piece or in plural pieces, and only one first shoulder 10141 and one second shoulder 10121 are provided in the present embodiment.

In this embodiment, the output shaft 101 is preferably made of a metal material, and the metal structure is convenient to machine, high in machining precision, high in rigidity, small in metal relative expansion coefficient, and less affected by temperature.

Furthermore, in order to protect the surface of the output shaft 101 made of a metal material, the output shaft 101 is often required to be subjected to surface treatment, the conventional process is blackening and phosphating, the embodiment breaks through the bias of the prior art, nickel plating is performed on the surface of the output shaft 101, the surface roughness of the output shaft 101 after machining is improved, the metal piece subjected to the nickel plating treatment is good in antirust performance, the problem of injection molding stress concentration caused by unstable surface roughness of the output shaft 101 after machining is solved, and the friction torque stability of the output shaft assembly 1 after injection molding is good. Fig. 6-13 respectively carry out high and low temperature tests, cold and hot stamping tests and friction durability tests on a plurality of sampled products, and it is obvious from the several figures that the products treated by nickel plating have the best consistency and stability under different tests, so that the output shaft assembly 1 obtained by the nickel plating surface treatment mode has improved antirust performance and better friction torque stability.

In this embodiment, the injection molded body 102 is injection molded by using POM material, and the injection molded body 102 injection molded by POM has high mechanical strength, rigidity and environmental resistance, and also has good dimensional stability, elasticity, self-lubrication and wear resistance, and the output shaft assembly 1 after insert injection molding has high friction torque stability.

Example two

In addition to the first embodiment, as shown in fig. 3 and 4(a), the output shaft 101 includes a first shaft section 1011, a fourth shaft section 1014, a second shaft section 1012 and a third shaft section 1013 which are sequentially connected in the axial direction, the fourth shaft section 1014 is located at the circumferential inner side of the injection bearing 1021, the second shaft section 1012 is located at the circumferential inner side of the injection gear 1022, the first shaft section 1011 and the third shaft section 1013 are respectively located at both ends of the injection molded body 102, the first shoulder 10141 is located on the fourth shaft section 1014, and the second shoulder 10121 is located on the second shaft section 1012.

First shaft section 1011: the end of the first shaft segment 1011 remote from the fourth shaft segment 1014 is provided with a single flat (as shown in figure 14) or double flat configuration (as shown in figure 3) for connection to an external drive end. The output shaft assembly 1 is installed on the motor, and the motor forms transmission structure with the transmission of the moment of being convenient for after the external assembly, increases flat potential on the output shaft assembly 1, can form peripheral radial spacing. The torque transmission is realized through the flat structure, the assembly is simple and convenient, the torque transmission device can be used in cooperation with different product structures, and the stability is good.

Second shaft segment 1012: the second axial section 1012 is provided with a second shoulder 10121 protruding radially outward, the cross section of the shoulder is circular, a second annular groove 10122 is formed between the second shoulder 10121 and the fourth axial section 1014, when there is only one second shoulder 10121 on the second axial section 1012, only one second annular groove 10122 is formed above the second shoulder 10121, when there are a plurality of second shoulders 10121 on the second axial section 1012, the adjacent second shoulders 10121 are spaced apart from each other, so that there is one second annular groove 10122 between the adjacent second shoulders 10121 and between the uppermost second shoulder 10121 and the fourth axial section 1014, respectively, as shown in fig. 4(a), there is only one second annular groove 10122 on the output shaft 101, as shown in fig. 15(a), there are two second annular grooves 10122 on the output shaft 101, as shown in fig. 15(b), and there are three second annular grooves 10122 on the output shaft 101.

Through static friction moment and kinetic friction moment tests of the output shaft assembly 1 under the three output shaft 101 structures of fig. 4(a), fig. 15(a) and fig. 15(b), it is known that when one second annular groove 10122 is provided, the stability (durability) of the output shaft assembly 1 is optimal, mainly because: the output shaft 101 is a metal part, and the expansion coefficient of the metal part is greatly different from that of the plastic (the injection molding body 102), when the output shaft 101 is cooled by injection molding, the shrinkage levels of the two components are different, when the output shaft 101 is subjected to hot injection molding, the outer layer of the plastic product is cooled, solidified and shrunk firstly, while the inner layer of the plastic article may still be a hot melt, the core layer may limit the shrinkage of the surface, resulting in a condition of compressive stress on the core layer, while too much of the second annular groove 10122 causes the distance between adjacent second annular grooves 10122 to decrease, because the surface is in a tensile stress state, the product is easy to crack and bubble, in order to ensure the uniform injection wall thickness in the whole injection molding process, the number of the second annular grooves 10122 on the output shaft 101 is designed to be one under the limitation of small injection space, poor injection caused by the fact that the width of the second annular grooves 10122 is small due to the fact that the number is too large is prevented, and the possibility that the injection molding body 102 cracks is greatly reduced.

To ensure the strength of the output shaft 101 and due to the limitation of the machining process, the axial height H0 and the radial depth H1 of the second annular groove 10122 need to be reasonably controlled (as shown in fig. 4(a)), specifically because: if the axial height H0 of the second annular groove 10122 is too small, the machining difficulty coefficient is too high, and the tool life is shortened, and preferably, the axial height H0 of the second annular groove 10122 is greater than or equal to 0.5 mm; if the radial depth H1 of the second annular groove 10122 is too large, scrap iron is left in the second annular groove 10122, which affects the injection molding of the assembly, and causes unstable friction force and even failure of the output shaft assembly 1, and in addition, it is ensured that the wall thickness of the plastic around the output shaft 101 is large enough, the internal stress around the insert is reduced, and the possibility of cracking of the injection molded body 102 is reduced, and preferably, the radial depth H1 of the second annular groove 10122 is less than or equal to 1 mm.

Fourth shaft segment 1014: the bearing is injected on the periphery of the fourth shaft section 1014, the fourth shaft section 1014 is provided with a first shoulder 10141 which is radially outwards extruded, the cross section of the shoulder is circular, a first annular groove 10142 is formed between the first shoulder 10141 and the first shaft section 1011, the axial height H0 of the first annular groove 10142 is greater than or equal to 0.5mm, and the radial depth H1 of the first annular groove 10142 is less than or equal to 1mm (the design principle of the first annular groove 10142 is the same as that of the second annular groove 10122, and the description is not repeated here).

Third shaft segment 1013: (1) as shown in FIG. 16, a shaft head step 10131 is provided on one end of the third shaft section 1013 away from the second shaft section 1012, and the diameter H8 of the shaft head step 10131 is 1.4-1.8 mm. As shown in fig. 17 and 18, when the output shaft assembly 1 is assembled into a motor, the shaft head step 10131 is positioned with a fixing plate flanging hole 5 of the motor, the fixing plate flanging boss 6 is arranged at the fixing plate flanging hole 5, the smaller the height H10 of the fixing plate flanging boss 6, the larger the stress at the bending position, the bending deformation and the shortened service life of the die are caused, if the height H10 of the fixing plate flanging boss 6 is too large, the interference between the fixing plate flanging boss 6 and a gear 15 in a gear set 10 is caused, so the height of the fixing plate flanging boss 6 is limited, the diameter H8 of the shaft head step 10131 is 1.4-1.8 mm (the relationship between the diameter of the shaft head step 10131 and the flanging boss height is that the larger the diameter of the shaft head step 10131 is, the larger the inner diameter of the fixing plate flanging hole 5 is, the higher the height of the fixing plate flanging boss 6 is determined by the processing technology of the fixing plate flanging hole 5, the fixing plate flanging hole 5 and the boss 6 are formed by punching), the height H11 of the shaft head step 10131 must be higher than the height H10 of the fixed plate flanging boss 6, so that the shaft head step 10131 is prevented from contacting the fixed plate flanging boss 6 to form surface-surface contact, the abrasion and mechanical loss of the shaft head step 10131 are caused, and the whole service life and performance noise of the whole machine are influenced.

(2) As shown in fig. 16, one end of the third shaft section 1013 connected to the second shaft section 1012 is provided with a flat milling step 10132, the flat milling step 10132 is connected to the shaft head step 10131, a diameter of the flat milling step 10132 is greater than a diameter of the shaft head step 10131, the flat milling step 10132 is to mill a plane on a circumferential surface of the cylindrical step structure, and the diameter of the flat milling step 10132 is to mill a diameter of the cylindrical step structure. Preferably, the diameter H9 of the milling flat step 10132 is 1.4-2.5 mm. In the machining process of the output shaft 101, the machining of different positions needs to be carried out after positioning, and under the premise that the strength of the output shaft 101 is ensured, the front end of the third shaft section 1013 is milled flat, so that the part machining positioning effect is achieved, the machining process is simplified, the cost is reduced, and the market competitiveness of the motor is improved.

EXAMPLE III

In addition to the first or second embodiment, as shown in fig. 19, an annular bead 10221 is provided on the lower end surface of the injection molded body 102. After the output shaft assembly 1 is assembled on the motor, because the internal parts of the motor are composed of a gear box and the like, according to different installation modes of the motor, the phenomenon that the lower surface of the injection molded body 102 is in surface contact with the single gear 15 exists, the annular convex rib 10221 is added, so that the injection molded body 102 is in surface-to-surface contact with the single gear 15, the friction resistance between the injection molded body 102 and the adjacent single gear 15 is reduced, the abrasion between the injection molded body 102 and the adjacent single gear 15 is reduced, and the mechanical loss is reduced.

Example four

In addition to the first embodiment, the second embodiment or the third embodiment, as shown in fig. 16 and 19, the lower end surface of the injection molded body 102 has a sunken step 10222 which is sunken upwards, and the injection gate 7 is located in the sunken step 10222. In the third embodiment, the sunken step 10222 is located radially inward of the annular bead 10221.

A sinking step 10222 with a certain depth is arranged on the lower end surface of the injection molding body 102, and an injection molding gate 7 is arranged in the sinking step 10222, so that even if burrs exist at the position of the injection molding gate 7, the interference between the injection molding body 102 and other parts is not influenced.

The gate location determines the flow profile, flow spacing and flow direction of the plastic melt in the mold cavity. If the size of runner is undersize, can make and fill the mould time extension, the injection molding body cools off great difference in the shrink that inhomogeneous arouses to after the fuse-element got into the die cavity, the temperature reduction quickens, and the fuse-element viscosity increases rapidly, causes to fill the mould under the high viscosity, thereby increase cooling internal stress and orientation stress, leads to the injection molding body also to have the hidden danger of scarce material. When the injection gate 7 is disposed at the position with the largest injection wall thickness (the surface of the sinking step 10222), the injection pressure, the holding pressure and the holding time are properly reduced, which is beneficial to reducing the orientation stress of the injection molded body 102. And the burr of the injection molding sprue 7 is lower than the lower surface of the injection molding body 102, so that the contact interference with other parts is prevented.

The selection of 7 reasonable positions of runner of moulding plastics is passed through to this embodiment, and the effectual bad hidden danger of moulding plastics that has avoided moulding plastics to bring improves product stability.

EXAMPLE five

An electrical machine comprising a housing assembly and, located within the housing assembly, a rotor 8, a stator assembly 9 and a gear set 10; the gear set 10 comprises a multi-stage single gear 15 and the output shaft assembly 1, wherein the multi-stage single gear is in meshed transmission with the multi-stage single gear, and the output shaft assembly 1 is located at the final stage of the gear set 10.

The components inside the casing assembly are the same as those of the stepping motor in the prior art, as shown in fig. 20, the rotor 8 is mounted on the middle shaft 14, the stator assembly 9 is mounted inside the casing, the upper pole plate fixing plate 13 assembly is mounted on the stator assembly 9, and the gear set 10 is mounted on the upper pole plate fixing plate 13 assembly, wherein the output shaft assembly 1 of the present embodiment is different from the output shaft assembly 1 in the prior art.

In the gear set 10, the output shaft assembly 1 is disposed at the last stage (as shown in fig. 21), because the output shaft assembly 1 is a friction mechanism, when the output end of the motor is subjected to an impact load, the injection molded body 102 of the output shaft assembly 1 slides and rubs to generate idle rotation, thereby blocking the transmission of power and achieving the purpose of protecting the single gear 15. If the friction mechanism is arranged on other non-final-stage transmission gears, because the final-stage gear is stressed and the teeth are broken without transmitting the load force to the previous-stage gear, the output shaft assembly 1 is arranged on the final stage and can effectively protect the single gear.

The casing assembly comprises a casing 11 and a cover plate 12, the output shaft assembly 1 extends out of the casing assembly through the cover plate 12, two mounting holes 1201 are formed in the cover plate 12, and the center of the output shaft assembly 1 and the centers of the two mounting holes 1201 are not on the same straight line.

The output shaft assembly 1 extending out of the surface of the cover plate 12 is a first shaft section 1011 of the output shaft 101, and is used for being assembled with a client to form a transmission mechanism, so that a power transmission effect is achieved.

The mounting hole 1201 is usually located on the central horizontal line of the motor, the output shaft assembly 1 is located on the upper portion of the central horizontal line of the motor and is not located on the same straight line with the mounting hole, the output shaft assembly 1 and the mounting hole 1201 form a stress surface, the stress of the cover plate 12 can be greatly loaded on the formed stress surface in the fastening process, and the mounting plate (the mounting hole 1201 is located on the mounting plate) of the cover plate 12 cannot be deformed (as shown in fig. 22) due to uneven stress, so that the quality of the motor is improved. In addition, the output shaft assembly 1 and the motor wiring harness 16 are respectively positioned at two sides of the motor (as shown in fig. 23), so that the installation at a client side is convenient.

In the description of the present invention, it is to be understood that the terms "central", "upper", "lower", "horizontal", "inner", "outer", "axial", "radial", "circumferential", and the like, indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are used merely for convenience of description and simplification of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In this specification, the schematic representations of the terms are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims (16)

1. The utility model provides an output shaft subassembly of bearing is moulded plastics in area which characterized in that: the injection molding device comprises an output shaft (101), an injection molding bearing (1021) and an injection molding gear (1022) which are sleeved on the output shaft (101), wherein the injection molding bearing (1021) is positioned at the upper end of the injection molding gear (1022); the injection molding bearing (1021) and the injection molding gear (1022) are integrally molded to form an injection molding body (102), and the output shaft assembly (1) is formed by insert injection molding of the output shaft (101) in the injection molding body mold (3).

2. The output shaft assembly with an injection molded bearing of claim 1 wherein: a first shoulder (10141) is arranged on a shaft section of the output shaft (101) which is in contact with the injection molding bearing (1021), and the ratio of the radial thickness D of the injection molding bearing (1021) to the diameter D0 of the first shoulder (10141) is 1/10-11/10.

3. The output shaft assembly with an injection molded bearing of claim 2, wherein: a second shoulder (10121) is arranged on a shaft section of the output shaft (101) which is in contact with the injection gear (1022), and the ratio of the radial thickness H6 of the injection gear (1022) to the diameter H7 of the second shoulder (10121) is 3/10-9/4.

4. The output shaft assembly with an injection molded bearing of claim 3 wherein: the number of the second shoulder (10121) is one or more than one.

5. The output shaft assembly with an injection molded bearing of claim 1 wherein: the output shaft (101) is made of a metal material, and the surface of the output shaft (101) is subjected to nickel plating treatment.

6. The output shaft assembly with an injection molded bearing of claim 3 wherein: the output shaft (101) comprises a first shaft section (1011), a fourth shaft section (1014), a second shaft section (1012) and a third shaft section (1013) which are sequentially connected along the axial direction, the fourth shaft section (1014) is positioned on the circumferential inner side of the injection molding bearing (1021), the second shaft section (1012) is positioned on the circumferential inner side of the injection molding gear (1022), the first shaft section (1011) and the third shaft section (1013) are respectively positioned at two ends of the injection molding body (102), the first shoulder (10141) is positioned on the fourth shaft section (1014), and the second shoulder (10121) is positioned on the second shaft section (1012).

7. The output shaft assembly with an injection molded bearing of claim 6 wherein: one end of the first shaft section (1011) far away from the fourth shaft section (1014) is provided with a single-flat or double-flat structure.

8. The output shaft assembly with an injection molded bearing of claim 6 wherein: a first annular groove (10142) is formed between the first shoulder (10141) and the first shaft section (1011).

9. The output shaft assembly with an injection molded bearing of claim 6 wherein: a second annular groove (10122) is formed between the second shoulder (10121) and the fourth shaft segment (1014).

10. The output shaft assembly with an injection molded bearing of claim 9 wherein: the axial height H2 of the second annular groove (10122) is greater than or equal to 0.5mm, and the radial depth H3 of the second annular groove (10122) is less than or equal to 1 mm.

11. The output shaft assembly with an injection molded bearing of claim 8, wherein: the axial height H0 of the first annular groove (10142) is greater than or equal to 0.5mm, and the radial depth H1 of the first annular groove (10142) is less than or equal to 1 mm.

12. The output shaft assembly with an injection molded bearing of claim 6 wherein: and a shaft head step (10131) is arranged at one end, far away from the second shaft section (1012), of the third shaft section (1013), and the diameter H8 of the shaft head step (10131) is 1.4-1.8 mm.

13. The output shaft assembly with an injection molded bearing of claim 12 wherein: one end of the third shaft section (1013) connected with the second shaft section (1012) is provided with a milling flat step (10132), and the diameter of the milling flat step (10132) is larger than that of the shaft head step (10131).

14. The output shaft assembly with an injection molded bearing of claim 1 wherein: the lower end face of the injection molding body (102) is provided with an annular convex rib (10221); and a sunken step (10222) which is sunken upwards is arranged at the radial inner side of the annular convex rib (10221), and the injection molding gate (7) is positioned in the sunken step (10222).

15. An electric machine comprising a housing assembly and a rotor (8), stator assembly (9) and gear set (10) located within the housing assembly; the gear set (10) comprises a multi-stage single gear (15) and the output shaft assembly (1) with the injection molded bearing of any one of claims 1-14, which are in mesh transmission, and the output shaft assembly (1) is located at the last stage of the gear set (10).

16. The electric machine of claim 15, wherein: the casing assembly comprises a casing (11) and a cover plate (12), the output shaft assembly (1) extends out of the casing assembly through the cover plate (12), two mounting holes (1201) are formed in the cover plate (12), and the center of the output shaft assembly (1) and the centers of the two mounting holes (1201) are not on the same straight line.

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