CN107431425B

CN107431425B - linear vibration motor

Info

Publication number: CN107431425B
Application number: CN201680017393.4A
Authority: CN
Inventors: 片田好纪; 小田岛慎
Original assignee: Nidec Copal Corp
Current assignee: Nidec Precision Corp
Priority date: 2015-04-10
Filing date: 2016-04-07
Publication date: 2019-12-13
Anticipated expiration: 2036-04-07
Also published as: WO2016163446A1; JP2016198733A; CN107431425A; JP6378125B2

Abstract

The displacement of the supporting position of the end part of the spring is solved, and the stability of the operating characteristic of the linear vibration motor is realized. A linear vibration motor (1) is provided with: a movable member (10), the movable member (10) having a magnet (2) and a weight (3); a frame (4), wherein the frame (4) supports the movable element (10) so as to be capable of reciprocating vibration; a coil (5) that is fixed to the frame (4), and that applies a driving force to the magnet (2) to vibrate the movable element (10); and a coil spring (6), wherein the coil spring (6) is provided between the frame (4) and the movable element (10), one or both of the movable element (10) and the frame (4) is/are provided with a support part (20) that supports an end part (6A) of the coil spring (6), the support part (20) has a tapered surface (21) that is inclined at a certain angle with respect to a central axis (6P) of the coil spring (6), and the end part (6A) of the coil spring (6) is supported in contact with the tapered surface (21).

Description

Linear vibration motor

Technical Field

The present invention relates to a linear vibration motor that reciprocally vibrates a movable member by signal input.

background

A vibration motor (or a vibration actuator) is widely used as a device which is built in a mobile electronic device and transmits a signal such as signal reception or warning to a carrier by vibration. In addition, a vibration motor has recently attracted attention as a device for realizing a tactile technique (skin feel feedback) in a human-machine interface such as a touch panel.

In development of various types of vibration motors, linear vibration motors are known which can obtain relatively large vibration by linearly reciprocating a movable element. The linear vibration motor is configured such that a movable element having a magnet and a weight is supported by a spring so as to be capable of reciprocating vibration, and an alternating current having a frequency equal to the natural vibration frequencies of the spring and the movable element is applied to a fixed coil, thereby applying a driving force for reciprocating vibration to the magnet (see patent document 1 below).

documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2012-016153

Disclosure of Invention

Technical problem to be solved by the invention

In a conventional linear vibration motor, a spring is disposed between a movable element and a housing to elastically support the movable element, and an end portion (a positioning ring portion) of the spring is engaged with a convex or concave spring receiving portion provided in the housing or the movable element to position a support position of the spring. At this time, there are the following problems: the position of the spring end relative to the spring-bearing portion can be offset within the tolerances of the inner/outer diameters of the spring end and the tolerances of the relief diameter of the spring-bearing portion.

the above-described offset is generated in the radial direction of the spring end, and therefore, the direction of the spring force is inclined with respect to the vibration direction of the movable element, or the position of the spring end is moved during the vibration of the movable element to change the direction of the spring force, which may adversely affect the operation characteristics of the linear vibration motor.

The present invention is directed to solving the above problems as an example of the technical problem. That is, an object of the present invention is to solve the deviation of the support position of the spring end portion and to stabilize the operation characteristics of the linear vibration motor.

Technical scheme for solving technical problem

In order to achieve the above object, the linear vibration motor of the present invention has the following structure.

The linear vibration motor includes: a movable member having a magnet and a weight; a frame that supports the movable element so as to be capable of reciprocating vibration; a coil fixed to the housing and configured to apply a driving force to the magnet to vibrate the movable element; and a coil spring provided between the housing and the movable element, wherein one or both of the movable element and the housing is provided with a support portion that supports an end portion of the coil spring, the support portion has a tapered surface that is inclined at a predetermined angle with respect to a central axis of the coil spring, and the end portion of the coil spring is supported in contact with the tapered surface.

effects of the invention

The linear vibration motor according to the present invention having the above-described features can support the end of the coil spring that reciprocally vibrates the movable element without positional deviation, and can stabilize the operating characteristics of the linear vibration motor.

Drawings

Fig. 1 is an exploded perspective view of a linear vibration motor according to an embodiment of the present invention.

3 fig. 3 2 3 is 3 an 3 explanatory 3 view 3 of 3 the 3 linear 3 vibration 3 motor 3 according 3 to 3 the 3 embodiment 3 of 3 the 3 present 3 invention 3( 3( 3 a 3) 3 is 3 a 3 front 3 view 3 and 3( 3 b 3) 3 is 3 a 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3) 3. 3

Fig. 3 is an explanatory view showing a support portion of a linear vibration motor according to an embodiment of the present invention ((a) is a convex support portion supporting a coil spring, and (b) is a concave support portion supporting the coil spring).

Fig. 4 is an explanatory view showing a support portion of a linear vibration motor according to another embodiment of the present invention.

3 fig. 3 5 3 is 3 an 3 explanatory 3 view 3 of 3 a 3 linear 3 vibration 3 motor 3 according 3 to 3 another 3 embodiment 3 of 3 the 3 present 3 invention 3( 3( 3 a 3) 3 is 3 a 3 front 3 view 3 and 3( 3 b 3) 3 is 3 a 3 sectional 3 view 3 taken 3 along 3 line 3 a 3- 3 a 3) 3. 3

fig. 6 is an explanatory view showing a mobile electronic device (mobile information terminal) equipped with the linear vibration motor according to the embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, common parts in the drawings are denoted by the same reference numerals, and redundant description of each drawing is omitted.

The linear vibration motor 1 of the embodiment of the present invention includes: a movable member 10, the movable member 10 having a magnet 2 and a weight 3; a frame 4, the frame 4 supporting the movable element 10 to be capable of reciprocating vibration; a coil 5, the coil 5 being fixed to the frame 4; and a coil spring 6, the coil spring 6 being provided between the movable element 10 and the frame 4. In the figure, the X direction represents the vibration direction, the Y direction represents the width direction intersecting the vibration direction, and the Z direction represents the height (thickness) direction.

As the magnet 2, the linear vibration motor 1(1A) shown in fig. 1 and 2 has three magnets 2A, 2B, 2C arranged along the vibration direction. Space yokes 7 are disposed between the magnets 2A, 2B, and 2C, respectively. The magnets 2A, 2B, and 2C are magnetized along the vibration direction (X direction in the figure), and are arranged so that the magnetic poles facing each other are the same. That is, if one magnetic pole of the magnet 2A is an N pole and the other magnetic pole is an S pole along the X direction, the magnetic poles of the magnet 2B disposed adjacent to the magnet 2A with the space yoke 7 therebetween are: the magnetic pole on the side closer to the magnet 2A is the S pole, the magnetic pole on the side opposite to the magnetic pole is the N pole, and the magnetic pole of the magnet 2C disposed next to the magnet 2B with the space yoke 7 interposed therebetween is: the magnetic pole on the side closer to the magnet 2B is the N pole, and the magnetic pole on the side opposite to the magnetic pole is the S pole.

The coil 5 through which the drive current flows is disposed around the space yoke 7 with a gap therebetween, and is fixed to the frame 4. The coil 5 is wound as follows: the magnetic flux from the space yoke 7 toward the magnetic body (the housing 4) disposed around the space yoke 7 passes through the coil 5, or the magnetic flux from the surrounding magnetic body (the housing 4) toward the space yoke 7 passes through the coil 5. Thereby, a driving force (lorentz force) along the X-axis direction is applied to the magnet 2(2A, 2B, 2C) including the space yoke 7. The magnets 2(2A, 2B, 2C) including the space yoke 7 are integrally connected and reinforced by a reinforcing member 8 provided to extend in the X-axis direction.

A pair of weights 3 are attached to both ends in the X direction of the magnet 2 that is integrally connected and reinforced. Thereby, the movable member 10 having the magnet 2 and the weight 3 is formed. In the example shown in fig. 1 and 2, a guide shaft 11 is fixed to the weight 3, and the guide shaft 11 extends in the X direction from both ends of the weight 3.

The frame 4 has a bearing 12 for slidably supporting the guide shaft 11, and thereby supports the movable element 10 to which the guide shaft 11 is fixed so as to be reciprocally vibrated in the X direction. In the illustrated example, the frame 4 is formed by fixing front portions 4D and 4E formed of a pair of plate pieces to a plate body having a bent bottom portion 4A and side portions 4B and 4C, and attaching a flat upper lid portion 4F, and the frame 4 has a box shape that is long in the vibration direction (X direction) and thin in the thickness direction (Z direction).

The coil springs 6 are provided between the movable element 10 and the housing 4 so as to be elastically deformable in compression along the X direction, and in this example, two coil springs 6 are disposed on each of the left and right sides in the X direction, and four coil springs 6 in total are disposed. The four coil springs 6 are disposed at positions symmetrical with respect to the axis along which the guide shaft 11 extends.

both the movable element 10 and the housing 4 are provided with a support portion 20, and the support portion 20 supports the end portion 6A of the coil spring 6. In the illustrated example, the support portion 20 is provided on both the movable element 10 and the housing 4, but the support portion 20 may be provided only on one of the movable element 10 and the housing 4, the one end portion 6A of the coil spring 6 may be supported by the support portion 20, and the other end portion 6A of the coil spring 6 may be fixed to the other of the movable element 10 and the housing 4 by welding or the like. In the illustrated example, the support portion 20 is provided on the front portions 4D and 4E of the housing 4 and on the end of the weight 3 of the movable element 10.

In fig. 3(a), a specific structure of the support portion 20 is shown. The support portion 20 has a tapered surface 21, and the end portion 6A of the coil spring 6 abuts on the tapered surface 21. The support portion 20 of the example shown in fig. 3(a) has a convex portion that enters the end portion 6A of the coil spring 6, and a tapered surface 21 that abuts the inside of the end portion 6A is provided on the outer side surface of the convex portion.

The tapered surface 21 is inclined at a certain angle (taper angle θ) with respect to the central axis 6P of the coil spring 6. The tapered surface 21 is provided around the center axis 6P over the entire circumference or partially around the center axis 6P to such an extent that the end portion 6A of the coil spring 6 can be positioned, and has a constant taper angle θ with respect to the center axis 6P on all surfaces.

When the tapered surface 21 is provided in the support portion 20 and the inner side of the end portion 6A of the coil spring 6 is brought into contact with the tapered surface 21, even when the dimension of the inner diameter W1 of the end portion 6A of the coil spring 6 is deviated from the set value to some extent, the position in contact with the tapered surface 21 can be changed and the end portion 6A can be supported by the tapered surface 21 without deviation as long as the deviation is within the range of the minimum diameter T1 and the maximum diameter T2 of the tapered surface 21. The difference between the maximum diameter T2 and the minimum diameter T1 of the tapered surface 21 can be set appropriately in consideration of the tolerance of the inside diameter W1 of the end portion 6A of the coil spring 6 and the dimensional tolerance of the tapered surface 21.

Fig. 3(b) shows another embodiment of the support portion 20. In this example, the support portion 20 has a recess for accommodating the end portion 6A of the coil spring 6, and a tapered surface 21 that contacts the outside of the end portion 6A of the coil spring 6 is provided on the inner surface of the recess. In this example, as in the above example, the tapered surface 21 is inclined at a predetermined angle (taper angle θ) with respect to the central axis 6P of the coil spring 6.

in this example, by providing the tapered surface 21 in the support portion 20 and bringing the outer side of the end portion 6A of the coil spring 6 into contact with the tapered surface 21, even when the dimension of the outer diameter W2 of the end portion 6A of the coil spring 6 deviates to a certain extent from the set value, the position of contact with the tapered surface 21 can be changed and the end portion 6A can be supported by the tapered surface 21 without any deviation as long as the deviation is within the range between the minimum diameter T1 and the maximum diameter T2 of the tapered surface 21.

The linear vibration motor 1(1A) shown in fig. 1 and 2 applies an alternating current of a frequency equal to the natural vibration frequency of the coil spring 6 and the movable element 10 to the coil 5, thereby applying a driving force for reciprocating vibration to the magnet 2 including the space yoke 7, thereby reciprocating vibrating the movable element 10 in the X direction. At this time, since the end portion 6A of the coil spring 6 is supported by the support portion 20 without being displaced, the direction of the elastic force of the coil spring 6 is fixed, and stable operation characteristics can be exhibited.

In particular, by matching the central axis of the support 20 with the axial direction of the guide shaft 11, the direction of the elastic force of all the coil springs 6 can be made parallel to the axial direction of the guide shaft 11, and stable reciprocating vibration along the axial direction of the guide shaft 11 can be achieved. At this time, the coil spring 6 is elastically deformed along the central axis 6P thereof, and a problem that the coil spring 6 is bent and deformed to contact the housing 4 can be avoided. Further, since the elastic force of the coil spring 6 can be caused to act symmetrically with respect to the guide shaft 11, the problem that the movable element 10 rotates around the axis of the guide shaft 11 at the time of reciprocating vibration can be solved.

unlike the linear vibration motor 1(1B) shown in fig. 1 and 2, the linear vibration motor 1(1B) shown in fig. 4 and 5 has a configuration in which a movable element 10 is supported by a frame 4 so as to be capable of reciprocating vibration via a rolling element (bearing) 13. A plurality of (three in the illustrated example) rolling elements 13 are arranged in a dispersed manner on one surface side of the weight 3 of the mover 10. A groove 3P is formed in one surface of the weight 3 along the vibration direction (X), and the rolling elements 13 are held in the groove 3P. In the upper lid portion 4F of the housing 4, a groove portion 4F1 is formed at a position facing the groove 3P, and the groove 3P and the groove portion 4F1 hold the rolling elements 13 therebetween.

The movable member 10 has a movable frame 14, and two weights 3 and two magnets 2D, 2E are fixed to the movable frame 14. The two magnets 2D, 2E are arranged in the X direction and magnetized in opposite directions to each other along the Z direction. The coil 5 having a pair of linear portions extending in the Y direction with respect to the two magnets 2D, 2E is fixed to the upper lid portion 4F, and the coil 5 fixed to the upper lid portion 4F is disposed so that the coil 5 crosses a magnetic flux from one of the two magnets 2D, 2E to the other of the two magnets 2D, 2E via the upper lid portion 4F, which is a magnetic body.

In the linear vibration motor 1(1B), the support portion 20 is provided at the end of the movable frame 14 and the front portions 4D and 4E of the frame 4, and the end 6A of the coil spring 6 is supported by the support portion 20. In the linear vibration motor 1(1B), an alternating current having a frequency equal to the natural frequencies of the coil spring 6 and the mover 10 is also applied to the coil 5, and thereby a driving force for reciprocating vibration is applied to the magnet 2(2D, 2E), and the mover 10 is caused to reciprocate along the groove 3P or the groove portion 4F 1. At this time, since the end portion 6A of the coil spring 6 is supported by the support portion 20 without being displaced, the direction of the elastic force of the coil spring 6 is fixed, and stable operation characteristics can be obtained.

The form of the linear vibration motor 1 according to the embodiment of the present invention is not limited to the above example, and an embodiment of the present invention having the support portion 20 can be formed as long as it is: the linear vibration motor includes: a movable member 10, the movable member 10 having a magnet 2 and a weight 3; a frame 4, the frame 4 supporting the movable element 10 to be capable of reciprocating vibration; a coil 5 fixed to the housing 4, the coil 5 applying a driving force to the magnet 2 to vibrate the movable element 10; and a coil spring 6, the coil spring 6 being disposed between the frame 4 and the movable element 10, and being elastically deformed by vibration of the movable element 10.

The linear vibration motor 1 according to the embodiment of the present invention can obtain stable reciprocating vibration with a reduced thickness by using the frame 4 having a flat box shape. In particular, even when the frame 4 is made thin, which is close to the thickness of the movable element 10, the contact between the coil spring 6 and the frame 4 can be avoided as much as possible, and the thin linear vibration motor 1 with less noise can be obtained.

Fig. 6 shows a mobile information terminal 100 as an example of an electronic device equipped with the linear vibration motor 1 according to the embodiment of the present invention. The portable information terminal 100 having the linear vibration motor 1 which can obtain stable vibration and can realize thinning and width direction compacting can transmit the operation start and end time of the signal receiving or warning function in the communication function to the user by the stable vibration which is not easy to generate noise. Further, by making the linear vibration motor 1 thin and compact in the width direction, the portable information terminal 100 which is required to have high portability and design properties can be obtained. Further, since the linear vibration motor 1 has a compact shape in which each part is housed in the rectangular parallelepiped housing 4 with a suppressed thickness, it can be installed in a thin mobile information terminal 100 with a high space efficiency.

While the embodiments of the present invention have been described in detail with reference to the drawings, the specific configurations are not limited to the embodiments described above, and the present invention includes design changes and the like within a range not departing from the gist of the present invention. In addition, the above embodiments can be combined by following the respective techniques as long as there is no particular contradiction or problem in the purpose, structure, and the like.

(symbol description)

1(1A, 1B): a linear vibration motor for driving the vibration motor,

2(2A, 2B, 2C, 2D, 2E): a magnetic body which is provided with a magnetic body,

3: weight, 3P: the groove is provided with a plurality of grooves,

4: frame, 4A: bottom surface portion, 4B, 4C: sidewall portions, 4D, 4E: the front part of the human body is provided with a front face part,

4F: upper lid portion, 4F 1: the groove part is provided with a groove part,

5: coil, 6: coil spring, 6A: end, 6P: a central shaft is arranged at the center of the rotary shaft,

7: spacer yoke, 8: the strength member is a member for reinforcing the tire,

10: movable member, 11: guide shaft, 12: a bearing is arranged on the bearing seat, and the bearing seat,

13: rolling element (bearing), 14: the movable frame is provided with a movable frame,

20: support portion, 21: tapered surface, θ: the cone angle.

Claims

1. A linear vibration motor, comprising:

A movable member having a magnet and a weight;

a frame that supports the movable element so as to be capable of reciprocating vibration;

A coil fixed to the housing and applying a driving force to the magnet to vibrate the movable element; and

A coil spring provided between the frame and the movable member,

a support portion for supporting an end portion of the coil spring is provided on one or both of the movable element and the housing,

the support portion has a tapered surface inclined at a predetermined angle with respect to a central axis of the coil spring, and an end portion of the coil spring is supported in contact with the tapered surface,

The linear vibration motor has a guide shaft supported by the frame, the movable element vibrates in an axial direction along the guide shaft,

the coil spring is disposed at a position symmetrical to an axis along which the guide shaft extends.

2. The linear vibration motor of claim 1,

The support portion has a convex portion that enters an end portion of the coil spring, and the tapered surface that the inner side of the end portion contacts is provided on an outer side surface of the convex portion.

3. The linear vibration motor of claim 1,

The support portion has a recess for accommodating an end portion of the coil spring, and the tapered surface is provided on an inner surface of the recess so that an outer side of the end portion is in contact with the tapered surface.

4. the linear vibration motor according to any one of claims 1 to 3,

The movable member is supported by sliding or rolling with respect to the frame.

5. a mobile electronic device, characterized in that,

there is the linear vibration motor of any one of claims 1 to 4.