An injection molded stepper motor

Abstract

The present invention relates to an injection molded stepper motor, which comprises a stator component, a rotor component, an injection molded front end cover, an injection molded rear end cover, a front bearing, a front bearing chamber, a rear bearing and a rear bearing chamber. The rotor component is installed in the stator component. Both ends of the rotating shaft of the rotor component are respectively connected with the front bearing and the rear bearing. The front bearing is placed in the front bearing chamber, and the rear bearing is placed in the rear bearing chamber. The injection molded front end cover and the injection molded rear end cover are respectively arranged at both ends of the stator component. A first injection molded slot is provided on the side of the injection molded front end cover close to the stator component, and a second injection molded slot is provided on the side of the injection molded rear end cover close to the stator component. Compared with the prior art, the present invention has the advantages of improving the precision of the matching dimensions of the bearing mounting surfaces of the front and rear end covers, preventing the phenomenon of stator-rotor rubbing and stator-rotor sweeping during the operation of the motor, and greatly improving the quality of the motor, etc.

Description

Technical Field

[0001] The present invention relates to a stepping motor, and more particularly to an injection molded stepping motor. Background Art

[0002] The structure of the existing injection molded stepping motor is as Figures 1-3 shown, including a stator component 1, a rotor component 2, a front end cover 3, a rear end cover 4, a front bearing 5, a front bearing chamber 6, a rear bearing 7 and a rear bearing chamber 8. The rotor component 2 is installed in the stator component 1, and both ends of the rotating shaft of the rotor component 2 are respectively connected to the front bearing 5 and the rear bearing 7.

[0003] For the existing injection molded motor, the stator component 1 includes a stator core 11, a stator skeleton 12 and a core winding 13, as Figure 4 shown. After the stator component is completed, injection molding is carried out at the front and rear of the stator component, as Figure 5 shown, to integrally mold the front and rear injection molded end covers of the motor and the stator component to form an injection molded stator component.

[0004] The front bearing 5 and the rear bearing 7 of the motor are respectively placed in the front bearing chamber 6 and the rear bearing chamber 8 (the materials of the front and rear bearing chambers are aluminum or iron). The front and rear bearing chambers are matched with the injection molded front and rear end covers. The fitting accuracy of the installation of the motor stator and rotor depends on the fit between the front and rear bearing chambers and the injection molded front and rear end covers. Since the materials of the front and rear bearing chambers are metals and have good machining properties, high tolerances can be guaranteed, usually in the range of 0 to 0.005 mm. Therefore, the accuracy of the installation fit lies in the inner diameter and tolerance of the injection molded front and rear end covers.

[0005] After the stator component is completed and positioned by the inner diameter of the stator core, the front end cover 3 and the rear end cover 4 of the motor are injection molded at both ends of the stator component 1, as Figure 6 shown. The inner diameter of the stator core is φ1, and the inner diameter of the front and rear injection molded end covers after injection molding is φ2. Since the air gap of the stepping motor is small, generally 0.04 to 0.05 mm, the inner diameter of the stator needs to be honed to ensure the air gap size and consistency. The entire injection molded stator component is honed. After honing, the inner diameter of the stator is φ. The materials of the injection molded front and rear end covers are plastics, nylons or resins and other materials. Since the hardness of these materials is not high, when the honing bar cuts at high speed, the cutting effect on plastics, nylons or resins and other materials is not as good as that on metals, and usually large extrusion and deformation will occur. After the honing process is completed and the injection molded stator cools down, the inner diameter of the front and rear injection molded end covers will be smaller than the inner diameter φ of the stator, and the inner diameter tolerance of the front and rear injection molded end covers is within 0 to 0.1 mm. This will greatly make it difficult to determine the installation fit dimensions of the front and rear bearing chambers, and further cause the problem of non-concentric installation of the front and rear bearings, resulting in uneven air gap of the motor and excessive positioning torque. Seriously, when the motor operates at high temperature, it will also cause the phenomenon of stator-rotor rubbing and sweeping, and there are great quality hidden dangers in the motor. Summary of the Invention

[0006] The object of the present invention is to provide an injection molded stepping motor to overcome the defects existing in the above-mentioned prior art.

[0007] The object of the present invention can be achieved by the following technical solutions:

[0008] An injection molded stepping motor, comprising a stator component, a rotor component, an injection molded front end cover, an injection molded rear end cover, a front bearing, a front bearing chamber, a rear bearing and a rear bearing chamber. The rotor component is installed in the stator component. Both ends of the rotating shaft of the rotor component are respectively connected to the front bearing and the rear bearing. The front bearing is placed in the front bearing chamber, and the rear bearing is placed in the rear bearing chamber. The injection molded front end cover and the injection molded rear end cover are respectively arranged at both ends of the stator component. A first injection molded slot is provided on the side of the injection molded front end cover close to the stator component, and a second injection molded slot is provided on the side of the injection molded rear end cover close to the stator component.

[0009] Preferably, the first injection molded slot and the second injection molded slot have the same structure.

[0010] Preferably, the number of the first injection molded slot and the second injection molded slot is the same.

[0011] Preferably, the width of the slot opening of the injection molded slot is the same as the width of the slot opening of the stator slot of the stator component.

[0012] Preferably, the width of the slot opening of the injection molded slot is 1 mm to 5 mm.

[0013] Preferably, the depth of the slot opening of the injection molded slot is 1 mm to 5 mm.

[0014] Preferably, the injection molded slot is a straight slot.

[0015] Preferably, the injection molded slot is a trapezoidal slot.

[0016] Preferably, the position of the slot opening of the injection molded slot is consistent with the position of the slot opening of the stator slot of the stator component.

[0017] Preferably, the number of the injection molded slots is consistent with the number of the stator slots of the stator component.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] Slots are provided on the inner sides of the front and rear injection molded end covers of the motor. The cutting effect of the honing bar on the segmented injection molding is better than that of the integral circular injection molding. Both the honing size and the accuracy can be guaranteed, improving the accuracy of the mating dimensions of the bearing mounting surfaces of the front and rear end covers, preventing the phenomenon of stator-rotor rubbing and stator-rotor sweeping during the operation of the motor, and greatly improving the quality of the motor. Description of the Drawings

[0020] Figure 1 Schematic front view structure of an existing injection molding motor;

[0021] Figure 2 Schematic three - dimensional structure of an existing injection molding motor;

[0022] Figure 3 Schematic exploded structure of an existing injection molding motor;

[0023] Figure 4 Schematic exploded structure of the stator component of an existing injection molding motor;

[0024] Figure 5 Schematic three - dimensional structure of the stator component of an existing injection molding motor;

[0025] Figure 6 Schematic sectional view structure of the stator component of an existing injection molding motor;

[0026] Figure 7 Schematic exploded structure of the injection molding stator component of the present invention;

[0027] Figure 8 Schematic structure of the injection molding front end cover of the present invention;

[0028] Figure 9 Another schematic structure of the injection molding front end cover of the present invention;

[0029] Figure 10 Schematic three - dimensional structure of the injection molding stator component of the present invention;

[0030] Figure 11 Schematic sectional view structure of the injection molding rear end cover of the present invention;

[0031] Wherein 1: stator component; 2: rotor component; 3: front end cover; 4: rear end cover; 5: front bearing; 6: front bearing chamber; 7: rear bearing; 8: rear bearing chamber; 9: injection molding front end cover; 10: injection molding rear end cover; 11: stator core; 12: stator skeleton; 13: stator winding; 91 - 99: first injection molding slots of the injection molding front end cover, 101 - 109: second injection molding slots of the injection molding rear end cover, 9`: another structure injection molding front end cover, 91`: first injection molding slot of the another structure injection molding front end cover. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0033] In order to improve the dimensional accuracy of the front and rear end covers of the injection molded product after honing as much as possible, ensure that the installation fit tolerance of the motor is within a controllable range, and improve the quality of the motor, as Figure 7 shown, the injection molded stepping motor of the present invention includes a stator component 1, a rotor component 2, an injection molded front end cover 9, an injection molded rear end cover 10, a front bearing 5, a front bearing chamber 6, a rear bearing 7, and a rear bearing chamber 8. The rotor component 2 is installed in the stator component 1. The two ends of the rotating shaft of the rotor component 2 are respectively connected to the front bearing 5 and the rear bearing 7. The front bearing 5 is placed in the front bearing chamber 6, and the rear bearing 7 is placed in the rear bearing chamber 8. The injection molded front end cover 9 and the injection molded rear end cover 10 are respectively arranged at both ends of the stator component 1. The injection molded front end cover 9 is provided with first injection molded slots 91-99 on the side close to the stator component 1, and the injection molded rear end cover 10 is provided with second injection molded slots 101-109 on the side close to the stator component 1.

[0034] As Figure 8 shown, there are nine first injection molded slots 91-99, which are evenly distributed on the injection molded front end cover 9. As Figure 11 shown, there are nine second injection molded slots 101-109, which are evenly distributed on the injection molded rear end cover 10.

[0035] The notch width of the injection molded slot is the same as the notch width of the stator slot of the stator component 1.

[0036] The notch width of the injection molded slot is 1 mm to 5 mm, preferably 3 mm. The notch depth of the injection molded slot is 1 mm to 5 mm, preferably 3 mm.

[0037] As Figure 8 shown, the injection molded slot is a straight slot. As Figure 9 shown, in another embodiment, the injection molded slot is a trapezoidal slot.

[0038] As Figure 10 shown, the notch position of the injection molded slot is the same as the notch position of the stator slot of the stator component 1. The number of the injection molded slots is the same as the number of the stator slots of the stator component 1.

[0039] After the stator component is injection molded, the whole stator component is honed. The inner diameter of the honed stator is φ. Since the injection molded front and rear end covers of the stator are provided with slots, the honing bar has a better cutting effect on the segmented injection molding than the integral circular injection molding, and the honing size and accuracy are greatly improved. It can ensure that the metal inner lining ring and the stator core have the same inner diameter φ and the same tolerance of 0 to 0.005 mm. With such accuracy and tolerance, better installation effects can be obtained during the assembly of the stator and rotor of the stepping motor, and the problems of stator-rotor rubbing and stator-core sweeping during operation can be greatly controlled, thus greatly improving the quality of the motor.

[0040] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An injection molded stepper motor, comprising a stator component (1), a rotor component (2), an injection molded front end cover (9), an injection molded rear end cover (10), a front bearing (5), a front bearing housing (6), a rear bearing (7) and a rear bearing housing (8). The rotor component (2) is installed in the stator component (1). Both ends of the rotating shaft of the rotor component (2) are respectively connected to the front bearing (5) and the rear bearing (7). The front bearing (5) is placed in the front bearing housing (6), and the rear bearing (7) is placed in the rear bearing housing (8). The injection molded front end cover (9) and the injection molded rear end cover (10) are respectively arranged at both ends of the stator component (1), and it is characterized in that, The injection-molded front end cover (9) is provided with first injection-molded slots (91-99) on the side close to the stator component (1), and the injection-molded rear end cover (10) is provided with second injection-molded slots (101-109) on the side close to the stator component (1); the notch positions of the injection-molded slots are the same as those of the stator slots of the stator component (1); the number of the injection-molded slots is the same as that of the stator slots of the stator component (1). After the stator component is injection-molded, the whole stator component is honed so that the metal inner lining ring and the stator core have the same inner diameter φ and the same tolerance; the notch width of the injection-molded slots is 1 mm to 5 mm; the notch depth of the injection-molded slots is 1 mm to 5 mm.

2. The injection molded stepper motor according to claim 1, characterized in that, The structures of the first injection-molded slots (91-99) and the second injection-molded slots (101-109) are the same.

3. An injection molding stepping motor according to claim 1, characterized in that, The numbers of the first injection-molded slots (91-99) and the second injection-molded slots (101-109) are the same.

4. A plastic injection stepping motor according to claim 1, characterized in that, The notch width of the injection-molded slots is the same as that of the stator slots of the stator component (1).

5. An injection molded stepper motor according to claim 1, characterized in that, The injection-molded slots are straight slots.

6. The injection molded stepper motor according to claim 1, wherein The injection-molded slots are trapezoidal slots.

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