Linear vibration motor

1. A linear vibration motor, including:

a housing with an accommodation space;

an elastic member in the accommodation space;

a vibration unit suspended in the accommodation space by the elastic member, including a weight with a through hole connected to the elastic member, a pole plate fixed in the through hole, and a magnet fixed to the pole plate;

a coil assembly for driving the vibration unit to vibrate, inserted in the through hole and spaced apart from the magnet;

wherein

the pole plate includes a body part fixed with the weight and a pair of positioning protrusions extending from two ends of the body part toward the coil assembly; and

the magnet includes a pair of positioning holes corresponding to the positioning protrusions, so that the magnet is fixed by an engagement between the positioning protrusions and the positioning holes, the body part of the pole plate is a rectangle having a long axis parallel to a vibration direction; the body part includes two long side walls parallel to a long axis direction thereof and two short side walls parallel to a short axis direction thereof, the long side walls extend parallel to the vibration direction, and the positioning protrusions extend from the long side walls, the positioning protrusions and the positioning holes both have rectangular with round corners cross-sections taken along the long axis direction of the body part.

2. The linear vibration motor as described in claim 1 , wherein, the housing comprises a bottom plate and an upper cover engaging with the bottom plate for enclosing the accommodation space; the elastic member is fixed on an inner side of the upper cover; the vibration unit is suspended in the upper cover, and the coil assembly is fixed on the bottom plate.

3. The linear vibration motor as described in claim 1 , wherein, the weight includes a first wall and a second wall parallel to the long side walls; the elastic member includes a first elastic member and a second elastic member disposed at two sides of the weight along the vibration direction; the first elastic member includes a first elastic arm, a pair of first fixing arms extending from two ends of the first elastic arm in a same direction, and a first connecting arm; the first fixing arms are fixed on the first wall, the first elastic arm is arranged spaced from the weight, and the first connecting arm is fixed on one side of the housing opposite to the second wall; the second elastic member includes a second elastic arm, a pair of second fixing arms extending from two ends of the second elastic arm in a same bending direction, and a second connecting arm; the second fixing arms are fixed on the second wall, the second elastic arm is arranged spaced from the weight, and the second connecting arm is fixed on a side of the housing opposite to the first wall of the weight.

4. The linear vibration motor as described in claim 3 , further including at least two first reinforcing blocks, one of the first reinforcing blocks is located on a side of the housing near the second wall of the weight and fixed on the housing; the other of the first reinforcing blocks is located on a side of the housing near the first wall of the weight and fixed on the housing.

5. The linear vibration motor as described in claim 4 , further including at least two second reinforcing blocks respectively located on a side of the first fixing arms and the second fixing arms close to the housing; the two second reinforcing blocks fix the first fixing arms and the second fixing arms on the first wall and the second wall respectively.