STATOR AND TERMINAL FIXING STRUCTURE THEREOF

A terminal fixing structure applied in a stator includes a wire terminal, a bus bar terminal, a metal ring and a solder joint structure. The wire terminal includes a first end, and the first end is a quadrilateral cylinder. The bus bar terminal includes a second end, and the second end is a quadrangular cylinder, wherein a sidewall of the first end and a sidewall of the second end are immediately-adjacent to each other. The metal ring is arranged around the first end and the second end. The solder joint structure connects an end surface of the first end and an end surface of the second end.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to China Application Serial Number 202310335530.0, filed Mar. 31, 2023 which is herein incorporated by reference in its entirety.

BACKGROUND

Field of Disclosure

The present disclosure relates to a terminal fixing structure, and particularly to a terminal fixing structure of a motor stator.

Description of Related Art

In the application of vehicle traction motors, regardless of low voltage or high power requirements, the wires wound in the stator accommodating slot must have sufficient cross-sectional area to withstand the maximum currents. Therefore, wire terminals and bus bar terminals should have such design to meet the current density requirements of the wire.

At present, an electrical connection between a wire terminal and a bus bar terminal is achieved by welding. When a vehicle is running, the welding joint surface between the wire terminal and the bus bar terminal will be subjected to a large mechanical stress due to the vibration generated during the running of the vehicle. Under excessive mechanical stress, the welding joint surface may be broken. In order to avoid the fracture of the welding joint surface, the quality of the solder joints must be ensured, and the specifications of the solder joints will be strictly defined.

Since the quality of solder joints is not easy to be strictly controlled in real time on the production line, it is easy to cause large deviations in the quality of solder joints. Overcoming such problem by improving the quality of solder joints usually accompanied by huge production costs and sacrifice of welding quality. Once the solder joints are unable to counteract the mechanical stress, the solder joints will be cracked, resulting in the malfunction of the stator and the inability to provide running power for the vehicle.

SUMMARY

The present disclosure provides a motor stator and its terminal fixing structure to deal with the needs of the prior art problems.

In one or more embodiments, a terminal fixing structure applied in a stator includes a wire terminal, a bus bar terminal, a metal ring and a solder joint structure. The wire terminal includes a first end, and the first end is a quadrilateral cylinder. The bus bar terminal includes a second end, and the second end is a quadrangular cylinder, wherein a sidewall of the first end and a sidewall of the second end are immediately-adjacent to each other. The metal ring is arranged around the first end and the second end. The solder joint structure connects an end surface of the first end and an end surface of the second end.

In one or more embodiments, a stator includes a stator core, a plurality of wire terminals, a plurality of bus bar terminals, a plurality of metal rings and a plurality of solder joint structures. The stator core includes multiple slot-positions. Each wire terminal includes a wire terminal end, and the wire terminal end is partially located in a corresponding one of the multiple slot-positions, the wire terminal end includes a first end and the first end is a quadrilateral cylinder. The bus bar terminals are located in the stator core, each bus bar terminal includes a bus bar terminal end, the bus bar terminal end comprising a second end and the second end being a quadrilateral cylinder, wherein a sidewall of the first end and a sidewall of the second end are immediately-adjacent to each other. Each metal ring is arranged around a corresponding first end and a corresponding second end. Each solder joint structure connects an end surface of the corresponding first end and an end surface of the corresponding second end.

In one or more embodiments, the wire terminals include an electrical phase terminal or an electrical neutral terminal.

In one or more embodiments, the solder joint structure is in physical contact with the metal ring.

In one or more embodiments, the metal ring has a length in an extension direction of the first end and the second end, and the length is greater than 2 millimeters.

In one or more embodiments, a distance between the sidewall of the first end and the sidewall of the second end that are immediately-adjacent to each other is smaller than 0.5 millimeter.

In one or more embodiments, the metal ring conformally contacts remaining sidewalls except the immediately-adjacent sidewalls of the first end and the second end.

In one or more embodiments, the metal ring is a polygon with rounded corners.

In one or more embodiments, a sidewall of the bus bar terminal has at least one stepped structure to restrict the metal ring.

In one or more embodiments, a cross-sectional area of the bus bar terminal is larger than a cross-sectional area of the wire terminal where the sidewall of the first end and the sidewall of the second end that are immediately-adjacent to each other.

In sum, the stator structure and its terminal fixing structure disclosed herein are surrounded by metal rings on two immediate-adjacent sidewalls to the terminal ends to share the mechanical stress caused by vibration, so that the quality of the solder joint structure can be properly adjusted down, thereby reducing manufacturing difficulty and improving production yield.

DETAILED DESCRIPTION

Reference will now be made in detail to the present embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used through the drawings and the description to refer to the same or like parts.

Reference is made toFIG.1, which illustrates a perspective view of a stator structure100according to one embodiment of the present disclosure. The stator structure100includes a stator core102, a plurality of wire terminals104and a bus bar106. The stator core102is formed by stacking multiple silicon steel sheets such that it is also called silicon steel sheet laminated structure. The stator core102has a rotor accommodation space150for accommodating a rotor (not shown). The stator core102has a plurality of slot-positions102aextending in an axial direction AD and arranged around the rotor accommodation space150so that a plurality of wire terminals104can be installed therein to form the winding of the stator. The bus bar106is used to connect the wire terminals104in series and connected to an external power supply.

Reference is made toFIG.2, which illustrates a perspective view of a stator structure according to one embodiment of the present disclosure. The stator structure has a portion of its bus bar removed to expose a bus bar terminal106a,a bus bar terminal106b,a bus bar terminal106c,a bus bar terminal106dand a bus bar terminal106e.In some embodiments, the bus bar terminal106a,the bus bar terminal106b,the bus bar terminal106c,the bus bar terminal106dand the bus bar terminal106eare all terminals made of conductive materials. In some embodiments, the bus bar terminal106a,the bus bar terminal106b,the bus bar terminal106c,the bus bar terminal106dand the bus bar terminal106eare terminals made of iron, aluminum, copper, tin, steel or alloys thereof.

FIG.3illustrates an enlarged view of a bus bar in a stator structure ofFIG.2according to one embodiment of the present disclosure. The bus bar terminal106aincludes two terminal ends107a,one of which is located at the radially inner edge of the stator core102(closer to the rotor accommodation space150), and the other is located at the radially outer edge of the stator core102(farther away from the rotor accommodation space150), so as to be paired with the corresponding wire terminals104and fixed by a metal ring110. The bus bar terminal106bincludes two terminal ends107b,one of which is located at the radially inner edge of the stator core102(closer to the rotor accommodation space150), and the other is located at the radially outer edge of the stator core102(farther away from the rotor accommodation space150), so as to be paired with the corresponding wire terminals104and fixed by the metal ring110. The bus bar terminal106cincludes two terminal ends107c,one of which is located at the radially inner edge of the stator core102(closer to the rotor accommodation space150), and the other is located at the radially outer edge of the stator core102(farther away from the rotor accommodation space150), so as to be paired with the corresponding wire terminals104and fixed by the metal ring110. The bus bar terminal106dincludes three terminal ends107dthat are all located at the radially inner edge of the stator core102(closer to the rotor accommodation space150), so as to be paired with the corresponding wire terminals104and fixed by the metal ring110. Two of the three ends107dare located side by side, and one of the two side-by-side ends107dis radially aligned with the terminal end107alocated at the radially outer edge of the stator core102. The bus bar terminal106eincludes three terminal ends107elocated at the radially outer edge of the stator core102(farther away from the rotor accommodation space150), so as to be paired with the corresponding wire terminals104and fixed by the metal ring110, two of which are located side by side, and one of the two side-by-side ends107eis radially aligned with the terminal end107clocated at the radially inner edge of the stator core102. In some embodiments, the terminal ends (107a,107b,107c,107d) located on the inner edge of the bus bar terminal are all paired with the wire terminal104on the inner side in the radial direction and fixed by the metal rings110. In some embodiments, the terminal ends (107a,107b,107c,107e) located on the outer edge of the bus bar terminal are all paired with the wire terminal104on the radially outer side thereof and fixed by the metal rings110. In some embodiments, the wire terminal104may be an electrical phase terminal or an electrical neutral terminal. In some embodiments, the bus bar terminal106a,the bus bar terminal106b,and the bus bar terminal106cdo not overlap each other, bus bar terminal106doverlaps the bus bar terminal106aand the bus bar terminal106bin the axial direction, and the bus bar terminal106eoverlapping the bus bar terminal106band the bus bar terminal106cin the axial direction, thereby reducing the volume occupied by the whole bus bar terminals.

Reference is made toFIG.4, which illustrates a fixing structure of a wire terminal and a bus bar terminal in a stator structure according to one embodiment of the present disclosure. The fixed structure includes an end of a wire terminal104paired with an end107of a bus bar terminal. The end of each wire terminal104is a quadrangular cylinder and includes multiple sidewalls105a,an end surface105band slopes105c.In this embodiment, the end surface105bis connected to the four sidewalls105aby the four slopes105c.The end107of each bus bar terminal is a quadrangular cylinder and includes multiple sidewalls108a,an end surface108band at least one rounded corner108c.The end surface108bof this embodiment is connected to two of the sidewalls108aby two rounded corners108c,and directly connected the other two sidewalls108a.In this embodiment, the metal ring110is arranged around three of the sidewalls105aof the end of the wire terminal104and three of the sidewalls108aof the end107of the bus bar terminal106to fasten the wire terminal104and the bus bar terminal106, thereby increasing the ability to resist shock damage. In some embodiments, the metal ring110has a length L in the axial direction AD of the two ends, and the length L is greater than 2 millimeters, so as to generate sufficient mechanical strength. In some embodiments, the metal ring110conformally contacts the sidewalls105aof the end of the wire terminal104and the sidewalls108aof the end107of the bus bar terminal106. In some embodiments, the metal ring110can be processed by a clamping tool so that its inner wall conformally contacts the sidewalls105aof the end of the wire terminal104and the sidewalls108aof the end107of the bus bar terminal106. In some embodiments, the metal ring110can be pre-shaped into a desired structure, and then sleeved to the sidewalls105aof the end of the wire terminal104and the sidewalls108aof the end107of the bus bar terminal106, and the four slopes105cof the wire terminal104and the two rounded corners108cof the end107of the bus bar terminal both help to make the metal ring110slide to the desired position easily. In some embodiments, the metal ring110is a metal ring made of iron, aluminum, copper, tin, steel or alloys thereof. In some embodiments, the metal ring110is made of the same material as the wire terminal104and the bus bar terminal106.

Reference is made toFIG.5, which illustrates the fixing structure inFIG.4with its metal ring removed. This figure shows that the end of a wire terminal104is paired with the end107of a bus bar terminal106, and the metal ring110is not put on the state. The end of the wire terminal104includes multiple sidewalls105a,an end surface105band multiple slopes105c,and in an embodiment that the end surface105bis connected to the four sidewalls105aby the four slopes105c.The end107of the bus bar terminal106includes multiple sidewalls108a,an end surface108band multiple rounded corners108c.The end surface108bof an embodiment is connected to two of the sidewalls108athrough the two rounded corners108c,and directly connected to the other two sidewalls108a.In some embodiments, part of the sidewall108afurther includes a stepped structure108dto restrict the sliding position of the metal ring110. In some embodiments, the stepped structure108dmay be located on one or both of the sidewalls108a.

Reference is made toFIG.6, which illustrates a top view of the fixing structure inFIG.4. The fixing structure includes an end of a wire terminal104paired with an end107of a bus bar terminal106, and a metal ring110is added surrounding the sidewalls105aof the end of the wire terminal104and the sidewalls108aof the end107of the bus bar terminal106. In some embodiments, a sidewall105aat the end of the wire terminal104and a sidewall108aat the end107of the corresponding bus bar terminal106face each other or are immediately-adjacent to each other, and the inner sidewall110bof the metal ring110surrounds and contacts the remaining three non-adjacent sidewalls105aof the wire terminal104, and surrounds and contacts the remaining three non-adjacent sidewalls108aof the end107of the bus bar terminal106, so that the end of the wire terminal104and the end107of the bus bar terminal106has a pair of sidewalls (105a,108a) that face each other and has a distance D therebetween less than 0.5 mm. The metal ring110is used to make the end of the wire terminal104and the end107of the bus bar terminal106to have a restrict force in the direction CR (even if the distance D is less than 0.5 mm), so as to increase the ability of resisting vibration damage. The direction CR is perpendicular to a pair of sidewalls (105a,108a) where the end of the wire terminal104is immediately-adjacent to the end107of the bus bar terminal106. In some embodiments, the metal ring110is a continuous closed-loop metal ring structure without discontinuous gaps. In some embodiments, the metal ring110is made of a pipe, and is a polygon with rounded corners110ain cross-section. This configuration can reduce processing complexity and improve yield. In some embodiments, the cross-sectional area of the end107of the bus bar terminal106is greater than the cross-sectional area of the end of the wire terminal104where the end107of the bus bar terminal106is immediately-adjacent to the end of the wire terminal104, so that the bus bar terminal106has a cross-sectional area that can meet higher current density requirements.

Reference is made toFIG.7, which illustrates a top view of the fixing structure inFIG.5. For ease of illustration, this figure shows a state where the end of a wire terminal104is paired with the end107of a bus bar terminal106and the metal ring110is not put on. The end of the wire terminal104includes multiple sidewalls105a,an end surface105band multiple slopes105c,and in an embodiment that the end surface105bis connected to the four sidewalls105aby the four slopes105c.The end107of the bus bar terminal106includes multiple sidewalls108a,an end surface108band a plurality of rounded corners108c.The end surface108bof an embodiment is connected to two of the sidewalls108athrough the two rounded corners108c,and directly connected to the other two sidewalls108a.In some embodiments (referring toFIG.5), part of the sidewalls108afurther include a stepped structure108dto restrict the sliding position of the metal ring110. It can be seen from the top view that the stepped structure108dis a structure formed by a pair of sidewalls108aat the end107of the bus bar terminal106, and the width between the pair of sidewalls108aincreases from the width W1between the paired rounded corners108cto the width W2between the outer edges of the stepped structure108dso as to restrict the sliding position of the metal ring110.

Reference is made toFIG.8, which illustrates a fixing structure according to one embodiment of the present disclosure. The fixing structure includes the end of a wire terminal104paired with the end107of a bus bar terminal106, and a metal ring110and a solder joint structure113aare added. The solder joint structure113ais used to connect an end surface of the end of the wire terminal104and an end surface of the end of the bus bar terminal106such that the two end surfaces are electrically connected. The metal ring110is used to share the mechanical stress caused by vibration, so that the quality of the solder joint structure113a(penetration depth, porosity, and pore size) can be properly adjusted down, thereby reducing manufacturing difficulty and improving production yield. In some embodiments, the width of the solder joint structure113acan restrict the metal ring110from falling off, and the aforementioned stepped structure108dcan restrict the position where the metal ring110slides (refer toFIGS.5and7), and the metal ring110is restricted between the solder joint structure113aand the stepped structure108d.In some embodiments, the solder joint structure113ais not in contact with the metal ring110.

FIG.9illustrates a fixing structure according to another embodiment of the present disclosure. The fixing structure includes the end of a wire terminal104paired with the end107of a bus bar terminal106, plus a metal ring110and a solder joint structure113b.Compared with the solder joint structure113ainFIG.8, the solder joint structure113bof this embodiment covers a larger area and is in contact with the metal ring110to secure the metal ring110. The metal ring110is used to share the mechanical stress caused by vibration, so that the quality of the solder joint structure113b(penetration depth, porosity, and pore size) can be properly adjusted down, thereby reducing manufacturing difficulty and improving production yield. In some embodiments, the width of the solder joint structure113acan restrict the metal ring110from falling off, and the aforementioned stepped structure108dcan restrict the position where the metal ring110slides (refer toFIGS.5and7), and the metal ring110is restricted between the solder joint structure113aand the stepped structure108d.The metal ring110is confined between the solder joint structure113band the stepped structure108d.

The stator structure and its terminal fixing structure disclosed herein are surrounded by metal rings on two immediate-adjacent sidewalls to the terminal ends to share the mechanical stress caused by vibration, so that the quality of the solder joint structure can be properly adjusted down, thereby reducing manufacturing difficulty and improving production yield.