Linear vibration motor

Abstract

A linear vibration motor has a magnet assembly sandwiched between a pair of counterweights, which are further sandwiched between a pair of springs, the magnet assembly, the counterweights and the pair of springs being disposed in a housing. An elongated central shaft passes through the magnet assembly and the pair of counterweights to secure the two. The counterweights have opposite top and bottom surfaces respectively formed with recesses, and the housing has a pair of inward protrusions formed on opposite top and bottom walls to be respectively received in the corresponding recesses to provide reliable support for the moving mass in the vertical direction. The counterweights have respective fixing structures formed on the end walls to secure opposite ends of the springs. The opposite ends of the central shaft can further extend out of the counterweights and pass through the springs to be secured to corresponding end walls of the housing.

Description

[Technical Field]

[0001] This invention relates to a linear vibration motor, and more particularly to a linear vibration motor that operates stably and reliably. [Background Technology]

[0002] Linear vibration motors, as shown in U.S. Patent Application Publication No. US20130169071A, are widely used in cellular phones. However, their structure is complex and assembly is cumbersome.

[0003] Therefore, it is necessary to provide a reliable and easy-to-assemble linear vibration motor to overcome the above-mentioned defects. [Summary of the Invention]

[0004] The technical problem to be solved by the present invention is to provide a linear vibration motor with stable and reliable operation characteristics.

[0005] To solve the above problems, the present invention can adopt the following technical solution: a linear vibration motor, comprising a housing with a receiving space, a coil assembly, a magnet assembly, a counterweight, a spring, and a central shaft housed within the receiving space. The receiving space is formed between two end walls of the housing that are spaced apart from each other in the longitudinal direction. The coil assembly includes a conductive coil located in the receiving space and a flexible cable extending from the housing. The magnet assembly includes at least one pair of magnets, each magnet having a through hole. The counterweight is provided in pairs and clamps the magnet assembly in the longitudinal direction. The counterweight and the magnet assembly together constitute a movable member. A pair of springs are provided and respectively held on the two end walls, and the movable member is clamped in the middle in a stretchable manner in the longitudinal direction. The central shaft extends through the magnet assembly in the longitudinal direction, and the two ends of the central shaft terminate in the pair of counterweights respectively. The central shaft is used to hold the magnet assembly and the counterweights together to restrict the relative movement between the magnet assembly and the counterweights. The movable member formed by the magnet assembly and the counterweights is suspended between the pair of springs.

[0006] Furthermore, each of the end walls forms a limiting structure to limit the spring.

[0007] Furthermore, the limiting structure consists of a pair of inwardly extending tabs spaced apart from each other in a transverse direction perpendicular to the longitudinal direction.

[0008] Furthermore, the tab is torn inward from the end wall to form an opening at the tear, and the linear vibration motor also includes a cap attached to the end wall to cover the opening.

[0009] Furthermore, the limiting structure is an inward protrusion extending in a transverse direction perpendicular to the longitudinal direction.

[0010] Furthermore, the central shaft has a square cross-section, and the through hole of the magnet assembly is a circular through hole through which the central shaft extends.

[0011] Furthermore, the housing includes a first housing and a second housing assembled vertically, the first housing including a top wall and a pair of long side walls, and the second housing including a bottom wall and a pair of end walls.

[0012] Furthermore, the magnet assembly also includes a yoke sandwiched between a pair of magnets in the longitudinal direction, the yoke having high permeability and low coercivity compared to the pair of magnets.

[0013] Furthermore, the spring has a rectangular cross-section.

[0014] Furthermore, the counterweight has opposing grooves in the vertical direction perpendicular to the longitudinal direction, and the housing has a pair of inward protrusions that are accommodated in the corresponding grooves to guide the counterweight to move longitudinally.

[0015] To solve the above problems, the present invention may also adopt the following technical solution: a linear vibration motor, comprising a housing having a receiving space, a coil assembly, a magnet assembly, counterweights, springs, and a central shaft housed within the receiving space, wherein the receiving space is formed between two end walls spaced apart in the longitudinal direction of the housing, the coil assembly includes a conductive coil located in the receiving space and a flexible cable extending from the housing, the magnet assembly includes at least a pair of magnets, each magnet having a through hole, a pair of counterweights are provided and clamp the magnet assembly in the middle in the longitudinal direction, the counterweights and the magnet assembly together constitute a movable member, a pair of springs are provided and respectively held on the two end walls, and clamp the movable member in the middle in a stretchable manner in the longitudinal direction, the central shaft extends in the longitudinal direction of the magnet assembly, the pair of counterweights and the pair of springs, and the opposite ends of the central shaft are respectively fixed on the corresponding end walls.

[0016] Furthermore, one end of each spring is held on a corresponding end wall, while the other end is held on a corresponding counterweight. The end wall or the corresponding counterweight has a limiting structure corresponding to the end of the spring. The limiting structure includes a protrusion located between two spaced plates of the corresponding counterweight or a pair of tabs formed on the corresponding end wall.

[0017] Furthermore, each of the counterweights has a groove, and the housing forms an inward protrusion, each inward protrusion extending into the corresponding groove in a vertical direction perpendicular to the longitudinal direction.

[0018] Compared to existing technologies, the linear vibration motor of the present invention has a magnet assembly sandwiched between a pair of counterweights, which are further sandwiched between a pair of springs. An elongated central shaft passes through the magnet assembly, the pair of counterweights, and the pair of springs, with opposite ends of the central shaft fixed to corresponding end walls of the housing. The central shaft has a square cross-section, while the corresponding through-holes in the magnet assembly and the counterweights are circular. The counterweights have grooves formed in opposite top and bottom surfaces, and the housing has a pair of inward protrusions formed on opposite top and bottom walls to be received in the corresponding grooves, thereby providing reliable support for the counterweights in the vertical direction. Each counterweight forms a protrusion to hold the corresponding spring in place. In an alternative embodiment, the central shaft may terminate within the counterweights for movement with the magnet assembly. [Attached Image Description]

[0019] Figure 1 This is a perspective view of the first embodiment of the linear vibration motor of the present invention.

[0020] Figure 2 yes Figure 1 A stereoscopic view from another perspective.

[0021] Figure 3 yes Figure 1 Exploded view of a linear vibration motor.

[0022] Figure 4 yes Figure 1 Another exploded view of a linear vibration motor.

[0023] Figure 5 yes Figure 4 A breakdown diagram from another perspective.

[0024] Figure 6 yes Figure 1 A further exploded view of a linear vibration motor.

[0025] Figure 7 yes Figure 6 A breakdown diagram from another perspective.

[0026] Figure 8 yes Figure 1 Side view.

[0027] Figure 9 yes Figure 1 A sectional view along line AA.

[0028] Figure 10 yes Figure 1 Sectional view along line BB.

[0029] Figure 11 This is a perspective view of a second embodiment of the linear vibration motor of the present invention.

[0030] Figure 12 yes Figure 11 A stereoscopic view from another perspective.

[0031] Figure 13 yes Figure 11 Exploded view of a linear vibration motor.

[0032] Figure 14 yes Figure 11 Another exploded view of a linear vibration motor.

[0033] Figure 15 yes Figure 14 A breakdown diagram from another perspective.

[0034] Figure 16 yes Figure 11 A further exploded view of a linear vibration motor.

[0035] Figure 17 yes Figure 16 A breakdown diagram from another perspective.

[0036] Figure 18 yes Figure 11 A sectional view along line CC.

[0037] Figure 19 yes Figure 11 A cross-sectional view along line DD.

[0038] Figure 20 This is a perspective view of the third embodiment of the linear vibration motor of the present invention.

[0039] Figure 21 yes Figure 20 A stereoscopic view from another perspective.

[0040] Figure 22 yes Figure 20 Exploded view of a linear vibration motor.

[0041] Figure 23 yes Figure 20 Another exploded view of a linear vibration motor.

[0042] Figure 24 yes Figure 23 A breakdown diagram from another perspective.

[0043] Figure 25 yes Figure 20 A further exploded view of a linear vibration motor.

[0044] Figure 26 yes Figure 25 A breakdown diagram from another perspective.

[0045] Figure 27 yes Figure 20 A cross-sectional view along line EE.

[0046] Figure 28 yes Figure 20 Sectional view along line FF.

[0047] The following detailed description, in conjunction with the accompanying drawings, will further illustrate the present invention. 【Detailed Implementation Methods】

[0048] See Figures 1 to 10 As shown in the first embodiment of the present invention, the linear vibration motor 100 includes a metal housing with a receiving space, a magnet assembly 185 housed in the receiving space, a coil assembly 175, a first counterweight 130, a second counterweight 132, a central shaft 190, a first spring 150, and a second spring 152. The housing is composed of a first housing 110 and a second housing 120 that are substantially symmetrical to each other and welded together along opposite edges. The first housing 110 has a horizontal plate 114 (i.e., a top wall), a long side wall 116, and a short side wall 112 (i.e., an end wall). The second housing 120 has a horizontal plate 124 (i.e., a bottom wall), a long side wall 126, and a short side wall 122 (i.e., an end wall). The short side wall 112 has an inward protrusion 118, which has a through-hole 119 in the longitudinal direction. The short side wall 122 has an inward protrusion 128, which has a through-hole 129 in the longitudinal direction. The horizontal plate 114 has a notch 113 to accommodate a lug 121 formed by the extension of the long sidewall 126, and the horizontal plate 124 has another notch 123 to accommodate another lug 111 formed by the extension of the long sidewall 116.

[0049] Within the housing space formed by the first housing 110 and the second housing 120, the magnet assembly 185 includes a first magnet 140 and a second magnet 142. A yoke 160 is sandwiched between the first magnet 140 and the second magnet 142 along the longitudinal direction. The yoke 160 is a soft magnetic material with higher permeability and lower coercivity compared to the first magnet 140 and the second magnet 142. The first magnet 140 has a circular through-hole 141 in the center along the longitudinal direction, and the second magnet 142 has another circular through-hole 143 in the center along the longitudinal direction. The yoke 160 has a circular through-hole 161 at its center. A first counterweight 130 and a second counterweight 132 sandwich the magnet assembly 185 along the longitudinal direction to jointly form a movable member. The first counterweight 130 has a circular through-hole 131 in its center, and the second counterweight 132 has another circular through-hole 133 in its center. A first spring 150 is mounted on a protrusion 118, and a second spring 152 is mounted on a protrusion 128. The protrusions 118 and 128 serve as limiting structures for the first spring 150 and the second spring 152. The first spring 150 and the second spring 152 have rectangular cross-sections; that is, both the first spring 150 and the second spring 152 are rectangular springs. The protrusions 118 and 128 are inwardly protruding in a transverse direction perpendicular to the longitudinal direction. Preferably, the protrusions 118 and 128 are generally rectangular, thus reliably holding the first and second springs 150 and 152 in place. A pair of counterweights 130 and 132, and a magnet assembly 185 located therebetween, are collectively stretched longitudinally between a pair of rectangular first and second springs 150 and 153.

[0050] A central axis 190 having a square cross-section extends through corresponding through-holes of the magnet assembly 185, that is, through the through-hole 141 of the first magnet 140, the through-hole 143 of the second magnet 142, and the through-hole 161 of the yoke 160, and further through the through-holes 131, 133 of a pair of counterweight blocks 130, 132 and the rectangular first spring 150 and second spring 152. The longitudinal ends of the central axis 190 are respectively fixed in the corresponding round holes 119, 129 of the protrusions 118, 128 by laser welding. It should be noted that in order to effectively accommodate the corresponding ends of the rectangular first spring 150, the first counterweight block 130 is provided with two spaced plates 136 and a protrusion 135 is formed between the two spaced plates 136, and the protrusion 135 is used to receive the corresponding end of the first spring 150. Similarly, a protrusion 137 is formed between the two spaced plates 138 of the second counterweight block 132, and the protrusion 137 is used to receive the corresponding end of the second spring 152. Preferably, the protrusions 135, 137 are substantially rectangular, so that the first and second springs 150, 152 in rectangular shape can be reliably held. In this embodiment, the four corners of the square cross-section of the central axis 190 can be curved or circular, so that the first counterweight block 130, the second counterweight block 132 and the magnet assembly 185 can translate smoothly relative to it. In addition, the through-holes of the first counterweight block 130 and the second counterweight block 132 can be squares with rounded corners to match the shape of the central axis 190. The coil assembly 175 includes a conductive coil 170 and a flexible cable 180 connected to each other. The flexible cable 180 is a flexible printed circuit. Wherein, the conductive coil 170 is located inside the housing to surround the magnet assembly 185, and there is a gap between the conductive coil 170 and the magnet assembly 185, while the flexible cable 180 extends outside the housing for power supply.

[0051] It can be understood that when the coil assembly 175 is operated, the magnet assembly 175 together with a pair of counterweight blocks 130, 132 will oscillate between a pair of springs 150, 152 along the longitudinal or circumferential direction, thereby causing a tactile vibration.

[0052] See Figures 11 to 19, which is the second embodiment of the present invention. This second embodiment is similar to the first embodiment, except that the first counterweight 130 is recessed on its upper and lower surfaces in the vertical direction perpendicular to the longitudinal direction to form opposite grooves 157, and the second counterweight 132 is recessed on its upper and lower surfaces in the vertical direction to form opposite grooves 159. The horizontal plate 114 and the horizontal plate 124 form inward protrusions 117 and 127 in the vertical direction and are received in the corresponding grooves 157 and 159 of the first and second counterweights 130 and 132 with a certain gap to guide the linear movement of the first and second counterweights 130 and 132, thereby stabilizing the overall oscillation of the magnet assembly 185 and the first and second counterweights 130 and 132 between the first spring 150 and the second spring 152. It should be noted that both the first embodiment and the second embodiment show that the movable member composed of the magnet assembly 185 and the first and second counterweights 130 and 132 can move along the central axis 190.

[0053] Refer Figures 20 to 28 As shown, this is the third embodiment of the present invention. Compared with the first and second embodiments, in the third embodiment, the longitudinal ends of the central axis 290 do not extend to the short side walls 112 and 122, but terminate in a pair of counterweights 130 and 132 respectively. The linear vibration motor 200 includes a metal housing, which is composed of a first housing 210 and a second housing 220 fixed together to jointly form an accommodation space. The first housing 210 includes a horizontal plate 212 and a pair of long side walls 214 extending in the longitudinal direction. The second housing 220 includes a horizontal plate 222 and a pair of short side walls 224 (i.e., end walls) extending in the transverse direction perpendicular to the longitudinal direction. Each of the short side walls 224 is respectively formed with a pair of inwardly extending tabs 225 spaced apart from each other in the transverse direction. The tabs 225 serve as the limiting structures of the limiting springs 250 and 252. The tabs 225 are formed by tearing inward from the short side walls 224 and openings are formed at the tearing points. A pair of covers 227 and 228 are respectively attached to the pair of short side walls 224 to cover the openings.

[0054] Similar to the first and second embodiments, the magnet assembly 285 includes a first magnet 240, a second magnet 242, and a yoke 260 sandwiched between the first magnet 240 and the second magnet 242 in the longitudinal direction. The first magnet 240 has a through hole 241, the second magnet 242 has a through hole 243, and the yoke 260 has a through hole 261. A first counterweight 230 and a second counterweight 232 sandwich the magnet assembly 285 in the middle along the longitudinal direction. The first counterweight 230 has a circular blind hole 231, and the second counterweight 232 has a circular blind hole 233. A rectangular first spring 250 and a rectangular second spring 252 are respectively installed on the first counterweight 230 and the second counterweight 232. In the longitudinal direction, the magnet assembly 285 and the first counterweight 230 and the second counterweight 232 are tensioned and sandwiched between the first spring 250 and the second spring 252.

[0055] A movable central shaft 290 with a square cross-section extends through corresponding through holes 241, 243, 261 of the magnet assembly 285 and terminates in blind holes 231, 233 of opposing first counterweights 230 and second counterweights 232. Similar to the first and second embodiments, the first counterweight 230 has a protrusion 235 for restraining the first spring 250, and the second counterweight 232 has a protrusion 237 for restraining the second spring 252. The coil assembly 275 includes a conductive coil 270 and a flexible cable 280, the conductive coil 270 surrounding the magnet assembly 285 and forming a gap between the conductive coil 270 and the magnet assembly 285, and the flexible cable 280 extending to the outside of the housing.

[0056] Understandably, when the coil assembly 275 is operated, the magnet assembly 285, together with the first counterweight 230 and the second counterweight 232, will oscillate longitudinally between the first spring 250 and the second spring 252, thereby generating tactile vibration. It is worth noting that in the first and second embodiments, this tactile vibration is essentially performed only in the longitudinal direction. However, in the third embodiment, because the two ends of the central shaft 290 in the longitudinal direction are no longer fixed to the housing, but are instead embedded within the first counterweight 230 and the second counterweight 232 respectively, forming a combination of the magnet assembly 285 and the first and second counterweights 230 and 232, tactile vibration is further generated in the vertical direction compared to the first and second embodiments.

[0057] The above embodiments are preferred embodiments of the present invention, but not all embodiments. Any equivalent changes to the technical solutions of the present invention made by those skilled in the art through reading this specification are covered by the claims of the present invention.

Claims

1. A linear vibration motor, comprising a housing having a receiving space, a coil assembly housed within the receiving space, a magnet assembly, a counterweight, a spring, and a central shaft, characterized in that: The housing forms the receiving space between two end walls spaced apart in the longitudinal direction. The coil assembly includes a conductive coil located in the receiving space and a flexible cable extending from the housing. The magnet assembly includes at least one pair of magnets, each magnet having a through hole. A pair of counterweights are provided and clamp the magnet assembly in the longitudinal direction. The counterweights and the magnet assembly together constitute a movable member. A pair of springs are provided and respectively held on the two end walls, and clamp the movable member in the longitudinal direction in a stretchable manner. The central shaft extends through the magnet assembly in the longitudinal direction, and its two ends terminate in the pair of counterweights. The central shaft is used to hold the magnet assembly and the counterweights together to restrict the relative movement between the magnet assembly and the counterweights. The movable member formed by the magnet assembly and the counterweights is suspended between the pair of springs.

2. The linear vibration motor as described in claim 1, characterized in that: Each of the end walls forms a limiting structure to limit the spring.

3. The linear vibration motor as described in claim 2, characterized in that: The limiting structure is a pair of inwardly extending tabs spaced apart from each other in a transverse direction perpendicular to the longitudinal direction.

4. The linear vibration motor as described in claim 3, characterized in that: The tab is formed by tearing inward from the end wall and forming an opening at the tear, and the linear vibration motor also includes a cover attached to the end wall to cover the opening.

5. The linear vibration motor as described in claim 2, characterized in that: The limiting structure is an inward protrusion extending in a transverse direction perpendicular to the longitudinal direction.

6. The linear vibration motor as described in claim 1, characterized in that: The central shaft has a square cross-section, and the through hole of the magnet assembly is a circular through hole through which the central shaft extends.

7. The linear vibration motor as described in claim 1, characterized in that: The housing includes a first housing and a second housing assembled vertically. The first housing includes a top wall and a pair of long side walls, and the second housing includes a bottom wall and a pair of end walls.

8. The linear vibration motor as described in claim 1, characterized in that: The magnet assembly also includes a yoke sandwiched between a pair of magnets in the longitudinal direction, the yoke having high permeability and low coercivity compared to the pair of magnets.

9. The linear vibration motor as described in claim 1, characterized in that: The spring has a rectangular cross-section.

10. The linear vibration motor as described in claim 1, characterized in that: The counterweight has opposing grooves in a vertical direction perpendicular to the longitudinal direction, and the housing has a pair of inward protrusions that are accommodated in the corresponding grooves to guide the counterweight to move longitudinally.

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