Vibrator

Abstract

A vibrator for transmitting vibrations to an application device. The vibrator has: a frame including an application device attachment surface for attaching the vibrator to an application device; a magnet unit configured to provide a magnetic field in the air gap; a coil assembly includes a voice coil mounted on a voice coil bobbin, where the voice coil bobbin is attached to a frame at a voice coil bobbin attachment surface on the frame. When the magnet unit is in the static position and the vibrator is static, the voice coil skeleton is configured to position the voice coil in the air gap. When the vibrator is activated by providing a current to the voice coil, the magnet unit is configured to move relative to the voice coil along a movement axis of the vibrator. The magnet unit is suspended from the frame by a suspension arrangement including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, the proximal suspension being closer to a voice coil bobbin attachment surface on the frame than the distal suspension when the vibrator is stationary. One of the proximal suspension and the distal suspension includes an elastomeric material configured to be elastically stretched such that a stiffness of the suspension including the elastomeric material increases as the magnet unit moves along the axis of motion away from the rest position.

Description

[0001] This application claims priority to UK Patent Application No. GB2218833.8, filed on December 14, 2022. Technical Field

[0002] The present invention relates to a vibrator for transmitting vibration to an application device. Background Art

[0003] Vibrators for transmitting vibration to an application device are known. Such devices are sometimes referred to as electric vibrators or electromechanical vibrators.

[0004] A vibrator, if attached to a vehicle seat (e.g., via the frame of the vehicle seat, seat foam, or other connecting components), can be used to transmit vibration to a person sitting on the vehicle seat. Such vibration can be used to provide a tactile warning to the person sitting on the seat, provide a massage to the person sitting on the seat, and / or enhance the auditory experience for the person sitting on the seat (e.g., helping the user to more strongly "feel" the bass).

[0005] Vibrators using two suspensions to provide stability against rocking motion are known, for example, see US4354067 (Yamada) and US4675907 (Itagaki).

[0006] Vibrators using only one (metal) suspension are also known, for example, see US6377145B1 (Kumagai) and US7372968B2 (Buos). In Buos, it is proposed to configure a single suspension to act on the plane where the centroid of the magnet unit is located to reduce rocking motion.

[0007] However, as discussed in more detail below, the present inventors have found that existing vibrator designs with two suspensions are difficult and costly to manufacture. While these problems are alleviated if only one metal suspension is used in the vibrator, the present inventors have found that even when a single metal suspension is installed as described in Buos, such a vibrator is still prone to rocking motion.

[0008] GB2108925.5 (which is excerpted and included as an appendix herein) discloses a vibrator for transmitting vibration to an application device, the vibrator having:

[0009] A frame including an application device attachment surface for attaching the vibrator to an application device;

[0010] A magnet unit configured to provide a magnetic field in an air gap;

[0011] A coil assembly, comprising a voice coil mounted on a voice coil former, wherein the voice coil former is attached to a frame at a voice coil former attachment surface on the frame, and wherein the voice coil former is configured to position the voice coil in an air gap when the vibrator is stationary;

[0012] Wherein the magnet unit is configured to move relative to the voice coil along the movement axis of the vibrator when the vibrator is activated by supplying current to the voice coil;

[0013] Wherein the magnet unit is suspended from the frame by a suspension device, the suspension device including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, and wherein the proximal suspension is closer to the voice coil former attachment surface on the frame than the distal suspension when the vibrator is stationary;

[0014] Wherein one of the proximal suspension and the distal suspension has a stiffness K1, and the other of the proximal suspension and the distal suspension has a stiffness K2, where K2 > K1, and the ratio K1 / K2 is 0.4 or less.

[0015] The inventors of GB2108925.5 found that, compared with using a single suspension, using two suspensions located at different positions along the movement axis helps to reduce rocking motion. Since there are two suspensions, it is not necessary to mount the suspension in the plane where the centroid of the magnet unit is located as described by Buos to reduce rocking motion.

[0016] However, the present inventors found that the vibrator taught by GB2108925.5 degrades over time because the suspension fatigues and becomes inefficient. In addition, the present inventors observed that the suspension with stiffness K1 is prone to tearing when the magnet unit reaches its maximum displacement or when the vibrator is used under high excitation forces.

[0017] US2013 / 0076162A1 proposes a single perforated suspension element made of silicone rubber for connecting the moving mass and the frame. However, US2013 / 0076162A1 is directed to a micro speaker, whose moving mass is much smaller than that of the vibrator. The present inventors found that using a single suspension element made of rubber as described in US2013 / 0076162A1 results in undesirable instability and rocking of the vibrator. In addition, using silicone rubber is not preferred because it is difficult to bond, which increases the manufacturing complexity and cost.

[0018] The present invention is proposed in view of the above considerations. Summary of the Invention

[0019] In a first aspect, the present invention may provide: a vibrator for transmitting vibration to an application device, the vibrator having:

[0020] A frame, which includes an application device attachment surface for attaching the vibrator to the application device;

[0021] A magnet unit configured to provide a magnetic field in an air gap;

[0022] A coil assembly including a voice coil mounted on a voice coil bobbin, wherein the voice coil bobbin is attached to a frame at a voice coil bobbin attachment surface on the frame, and wherein the voice coil bobbin is configured to position the voice coil in the air gap when the magnet unit is in a stationary position and the vibrator is stationary;

[0023] Wherein when the vibrator is activated by applying a current to the voice coil, the magnet unit is configured to move relative to the voice coil along the movement axis of the vibrator;

[0024] Wherein the magnet unit is suspended from the frame by a suspension device including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, and the proximal suspension is closer to the voice coil bobbin attachment surface on the frame than the distal suspension when the vibrator is stationary;

[0025] Wherein one of the proximal suspension and the distal suspension includes an elastomeric material configured to elastically stretch such that the stiffness of the suspension including the elastomeric material increases as the magnet unit moves away from the stationary position along the movement axis.

[0026] The inventors have found that including an elastomeric material in one of the proximal suspension and the distal suspension results in an increase in the amount of mechanical damping applied to the magnet unit by the suspension including the elastomeric material as the magnet unit moves away from the stationary position. Thus, compared to using a non-elastomeric material (such as the fabric suspension in GB2108925.5), the suspension including the elastomeric material can provide additional protection to the other suspension by reducing the stress on the other suspension when the magnet unit is close to its maximum displacement. Therefore, the mechanical damping progression introduced by the suspension including the elastomeric material can reduce the fatigue of the suspension including the elastomeric material, helping the suspension to be less prone to tearing, thereby improving the durability of the vibrator.

[0027] In addition, the gradually increasing stiffness and increased mechanical damping provided by the suspension including the elastomeric material can reduce the quality factor of the vibrator, thereby reducing the maximum displacement of the magnet unit at the resonant frequency. This can reduce the situation of the vibrator "bottoming out", i.e., the magnet unit contacting the frame when reaching the maximum displacement. Therefore, the vibrator can operate at a higher peak voltage without generating abnormal sounds and noise artifacts due to bottoming out. This is an important performance parameter of the vibrator.

[0028] In addition, the gradually increasing stiffness provided by the suspension including the elastomeric material can produce a useful power compression effect, wherein the maximum displacement of the magnet unit is limited, resulting in an upward shift of the resonant frequency of the vibrator at a high peak voltage, thereby increasing the vibration energy that can be transmitted to the application device.

[0029] Using a suspension including an elastomeric material to limit the maximum displacement of the magnet unit also means that a high-performance vibrator with a smaller form factor can be more easily achieved, where the damping effect of the suspension prevents the magnet unit from bottoming out when the frame is small, without the need for other expensive limiting components.

[0030] The other of the proximal suspension and the distal suspension (i.e., the suspension that does not include an elastomeric material) may be simply referred to as the "other" suspension in this article (for the first aspect of the present invention).

[0031] When no current is supplied to the voice coil and the magnet unit is not moving, the vibrator can be considered stationary. The position of the magnet unit when the vibrator is stationary can be referred to as the stationary position of the magnet unit.

[0032] In use, supplying current to the voice coil causes the magnet unit to move along the movement axis and deviate from its stationary position. The distance by which the magnet unit deviates from the stationary position along the movement axis can be referred to as the displacement of the magnet unit. The displacement of the magnet unit along the movement axis (from the stationary position) can be measured through any fixed position of the rigid part of the magnet unit.

[0033] The maximum negative displacement of the magnet unit can be regarded as the maximum distance that the magnet unit moves along the movement axis in the first direction from the stationary position until the magnet unit contacts the frame or the voice coil. The maximum positive displacement of the magnet unit can be regarded as the maximum distance that the magnet unit moves along the movement axis in the second direction (opposite to the first direction) from the stationary position. In this article, the first direction can be referred to as the negative direction, and the second direction can be referred to as the positive direction.

[0034] The application device can be any object or device that can be attached to the vibrator through the attachment surface of the application device on the frame. In some examples, the application device can be a vehicle seat.

[0035] Stiffness is a known parameter of the suspension, which can be measured by applying a controlled increasing and decreasing force to the suspension element and measuring the displacement at any applied force. Techniques for measuring stiffness are known. In the context of the present invention, stiffness can be measured relative to the displacement of the magnet unit from its stationary position (the position where the magnet unit is located when the vibrator is stationary), as Figure 18A and Figure 18B shown, the stiffness tends to increase as the displacement from the stationary position increases.

[0036] The suspension including an elastomeric material can be made entirely of an elastomeric material. For example, the suspension including an elastomeric material can be made of rubber (such as NBR, NR, EPDM). In other examples, the suspension including an elastomeric material can be made of a fabric containing an elastic material configured to stretch when the magnet unit moves relative to the voice coil.

[0037] In some examples, a suspension including an elastomeric material can be a composite component, including elastomeric and non-elastomeric materials.

[0038] A suspension including an elastomeric material can be configured such that the restoring force it provides (in Newtons) increases substantially linearly with the displacement of the magnet unit (from its rest position) within a certain region of the displacement of the magnet unit. In other words, a suspension including an elastomeric material can be configured to follow Hooke's law within a certain region of the displacement of the magnet unit.

[0039] A suspension including an elastomeric material can be configured such that the restoring force it provides (in Newtons) increases substantially linearly with the displacement of the magnet unit (from its rest position) between the maximum negative displacement and the maximum positive displacement of the magnet unit.

[0040] A suspension including an elastomeric material can be configured such that its stiffness is at least twice that when the magnet unit is in its rest position when the magnet unit is at its maximum positive displacement. Similarly, its stiffness is at least twice that at the rest position when the magnet unit is at its maximum negative displacement. Thus, when the magnet unit reaches its maximum displacement, a suspension including an elastomeric material can provide sufficient restoring force, thereby reducing the situation of the vibrator bottoming out and generating unnecessary noise.

[0041] A suspension including an elastomeric material can be annular and positioned to extend circumferentially around the magnet unit.

[0042] A suspension including an elastomeric material can be a flat disc extending circumferentially around the magnet unit.

[0043] In other examples, a suspension including an elastomeric material can be a coiled suspension. For example, a suspension including an elastomeric material can extend circumferentially around the magnet unit and have a curved (e.g., semi-circular) coiled portion when viewed in a plane containing the axis of motion. In some examples, a suspension including an elastomeric material can include two concentric flat portions connected by a curved (e.g., semi-circular) portion, forming a coil when viewed in a plane containing the axis of motion. A suspension including an elastomeric material can have a single-coil geometry. The coiled suspension is preferably shallow. For example, the maximum extent of the coiled suspension measured along the axis of motion does not exceed 40%, preferably does not exceed 30%, more preferably does not exceed 20% (on the same side of the axis of motion) of the width of the unclamped portion measured in a direction perpendicular to the axis of motion when the vibrator is at rest. The width of the unclamped portion of the coiled suspension can extend from the magnet unit to the inner surface of the frame, which corresponds to the outer circumference of the unclamped portion of the suspension.

[0044] By introducing a crimp geometry in a suspension including an elastomeric material, the manufacturing tolerances for positioning magnet units in a vibrator can be increased. Additionally, the crimp geometry can reduce the stress experienced at the connection between the suspension and the magnet unit and at the connection between the suspension and the frame (which typically includes glue applied to the outer periphery of the suspension). Introducing the crimp geometry may introduce an asymmetry and / or non-linearity in the stiffness provided by the suspension including the elastomeric material (when the magnet unit moves in a first (negative) direction from a rest position compared to when it moves in a second (positive) direction). However, by using a shallow crimp geometry, the suspension including the elastomeric material is more likely to elastically stretch within the maximum displacement range of the magnet unit, such that as the magnet unit moves away from the rest position along the axis of motion, the stiffness of the suspension increases compared to using a deep crimp geometry.

[0045] The crimp geometry of a suspension including an elastomeric material can be configured to meet the stiffness criteria defined herein, such as such that when the magnet unit is at maximum positive displacement, the stiffness of the suspension including the elastomeric material is at least twice the stiffness of the suspension including the elastomeric material when the magnet unit is at the rest position, and / or when the magnet unit is at maximum negative displacement, the stiffness of the suspension including the elastomeric material is at least twice the stiffness of the suspension including the elastomeric material when the magnetic unit is in the rest state.

[0046] A suspension including an elastomeric material can be attached to a magnet unit via an attachment ring. The attachment ring helps facilitate the connection between the suspension including the elastomeric material and the magnet unit. In particular, the attachment ring can increase the stiffness of the suspension connection portion, making it easier to handle and position the suspension during speaker assembly for bonding to the magnet unit.

[0047] The attachment ring can be attached to the suspension including the elastomeric material at the inner periphery of the suspension including the elastomeric material and extend circumferentially around the magnet unit. The attachment ring can be made of plastic (such as PC, PC-ABS, PP). The attachment ring can be attached to the suspension including the elastomeric material and the magnet unit by glue. In other examples, the attachment ring can be injection molded onto the magnet unit and attached to the suspension by glue. In this way, attaching the suspension including the elastomeric material to the magnet unit using an attachment ring may be more convenient and less costly because more conventional glue can be used to attach the attachment ring to the magnet unit rather than requiring glue specifically designed to bond with the elastomeric material in the suspension.

[0048] In an alternative example, a suspension including an elastomeric material can be directly attached to a magnet unit. For example, if the suspension including the elastomeric material is made of rubber, it can be directly attached to the magnet unit by rubber vulcanization. In this way, the connection between the suspension and the magnet unit can be simplified because glue specifically designed to bond with the elastomeric material in the suspension is not required.

[0049] In some examples, a suspension including an elastomeric material can be made of an air-impermeable material, where the suspension including the elastomeric material, together with the frame, is configured to enclose an air volume for resisting movement of the magnet unit along the movement axis when the vibrator is activated. In such examples, the suspension including the elastomeric material is preferably a proximal suspension because it is more convenient to enclose an air volume with a proximal suspension.

[0050] In other examples, a suspension including an elastomeric material can be made of a breathable material and / or a material including holes or slots.

[0051] Another suspension can be a metal suspension, i.e., made of metal. By giving it an appropriate geometry, the metal suspension can be configured to dominate or not dominate the overall stiffness of the suspension device according to the design requirements, thus helping to achieve the stiffness requirements described herein.

[0052] The metal suspension can be made of a metal plate. In some examples, the thickness of the metal plate can be 1 mm or less. The metal suspension can be a leaf spring configured to bend when the magnet unit moves relative to the voice coil along the movement axis.

[0053] The metal suspension can have one or more cuts to facilitate proper behavior. One or more cuts can have a spiral shape.

[0054] The metal suspension can be annular and positioned to extend circumferentially around the magnet unit.

[0055] Thus, the metal suspension can include one or more (preferably multiple, preferably at least three) attachment tabs located on its outer periphery, where one or more attachment tabs facilitate the mechanical connection of the distal suspension to the frame. More preferably, the frame includes one or more slots, each slot corresponding to a respective attachment tab on the outer periphery of the metal suspension, where one or more attachment tabs facilitate the mechanical connection of the distal suspension to the frame through a bayonet connection, where the attachment tabs engage with the corresponding slots in the frame. This helps to accurately position the metal suspension when attaching it to the frame.

[0056] In other examples, another suspension can be made of plastic, which is configured to bend when the magnet unit moves relative to the voice coil along the movement axis. In other examples, another suspension can be made of rubber or fabric. In some examples, for example, according to the design requirements, the stiffness of such a rubber or fabric suspension can be higher (or lower) than that of a suspension including an elastomeric material.

[0057] Preferably, the suspension including the elastomeric material is the proximal suspension and the other suspension (e.g., metal) is the distal suspension. This is particularly convenient for the manufacturing process of forming a vibrator from the constituent components, especially when the frame includes a main frame and a sub-frame (see below). In addition, the distal suspension may be exposed depending on how the vibrator is mounted to the application device, so the advantage is that the other suspension (which can be non-elastomeric and thus more durable and made of metal, for example) is exposed rather than the suspension including the elastomeric material. When the other suspension is a metal suspension, it is particularly preferred to have the suspension including the elastomeric material as the proximal suspension (since metal is particularly durable).

[0058] In some examples, it is also feasible that the suspension including the elastomeric material is the distal suspension and the other suspension is the proximal suspension.

[0059] Preferably, one of the proximal suspension and the distal suspension has a stiffness K1 and the other has a stiffness K2, where K2 > K1 when the vibrator is at rest, i.e., when the vibrator is at rest, the stiffness K2 of one of the proximal suspension and the distal suspension is greater than the stiffness K1 of the other.

[0060] In this example, herein, the proximal suspension or the distal suspension having a stiffness K2 may be referred to as the "main" or "dominant" suspension, and the other suspension having a stiffness K1 may be referred to as the "secondary" or "non-dominant" suspension.

[0061] The ratio K1 / K2 is preferably 0.4 or less (when the vibrator is at rest). The advantages of this configuration are described in the extract of GB2108925.5 provided as an appendix. Any features described in the appendix related to the suspension having a stiffness K1 and / or the suspension having a stiffness K2 can optionally be used in combination with any aspect of the present invention, unless clearly not allowed or explicitly avoided.

[0062] The stiffness K1 can be 0.1 N / mm or higher, preferably 0.2 N / mm or higher, more preferably 0.4 N / mm or higher (when the vibrator is at rest).

[0063] The stiffness K1 can be 20 N / mm or lower, preferably 10 N / mm or lower (when the vibrator is at rest).

[0064] In some examples, K1 can be in the range of 0.4 N / mm to 10 N / mm (when the vibrator is at rest).

[0065] In some examples, K1 can be in the range of 2 N / mm to 50 N / mm (when the vibrator is at rest).

[0066] The stiffness K2 can be 1 N / mm or higher, preferably 2 N / mm or higher (when the vibrator is at rest).

[0067] The stiffness K2 can be 100 N / mm or lower, preferably 50 N / mm or lower (when the vibrator is stationary).

[0068] In some examples, K2 can be in the range of 1 N / mm to 100 N / mm (when the vibrator is stationary).

[0069] The mass of the magnet unit can be 40 g or more.

[0070] The suspension having the stiffness K2 can be annular and positioned to extend circumferentially around the magnet unit.

[0071] The ratio K1 / K2 can be 0.35 or smaller (when the vibrator is stationary). The ratio K1 / K2 can be 0.3 or smaller, even 0.25 or smaller (when the vibrator is stationary). The lower the ratio K1 / K2 when the vibrator is stationary, the more dominant the suspension having the stiffness K2 is in providing the stiffness of the suspension device.

[0072] In some examples, the proximal suspension can have the stiffness K1 and the distal suspension can have the stiffness K2. In other examples, the proximal suspension can have the stiffness K2 and the distal suspension can have the stiffness K1.

[0073] Preferably, the suspension including the elastomeric material has the stiffness K1 (when the vibrator is stationary), while the other (e.g., metal) suspension has the stiffness K2 (when the vibrator is stationary).

[0074] Preferably, the suspension having the stiffness K2 (when the vibrator is stationary) is a metal suspension. The inventors have found that using a metal suspension as the suspension having the stiffness K2 and combining it with an elastic suspension as the suspension having the stiffness K1 is particularly advantageous in providing the above beneficial effects because such a combination can provide a vibrator that resists rocking motion and is easy to manufacture. In addition, such a combination provides a vibrator with a resonance frequency that is stable over time.

[0075] To avoid any doubt, the suspension including the elastomeric material can have the stiffness K2 (when the vibrator is stationary), while the other (e.g., metal) suspension can have the stiffness K1 (when the vibrator is stationary).

[0076] Furthermore, in some examples, the proximal suspension and the distal suspension can have the same stiffness when the vibrator is stationary (although it is generally preferred to have a dominant and a non-dominant suspension as described above, and the reasons for this can be understood from the attached appendix).

[0077] The vibrator can have a resonance frequency Fs. The resonance frequency Fs can be regarded as the frequency at which the displacement of the magnet unit along the movement axis reaches the maximum under a given RMS excitation input voltage.

[0078] Fs can be 30 Hz or higher, preferably 40 Hz or higher.

[0079] Fs can be 200 Hz or lower, preferably 100 Hz or lower, more preferably 70 Hz or lower.

[0080] In some examples, Fs can be in the range of 30 Hz to 200 Hz, such as in the range of 30 Hz to 70 Hz.

[0081] The magnet unit may include a U-shaped yoke, which is U-shaped when viewed in cross-section, where the U-shaped yoke has a base end corresponding to the bottom of the U-shape and an open end corresponding to the open end of the U-shape. Preferably, the U-shaped yoke is mounted in the vibrator, and its base end is farther from the voice coil attachment surface than the open end. In other examples, the magnet unit may include a T-shaped yoke, which is inverted T-shaped when viewed in cross-section.

[0082] Preferably, the U-shaped yoke includes an open end attachment surface at the open end, where the inner circumference of the proximal suspension connecting the frame and the magnet unit is attached to the open end attachment surface of the magnet unit.

[0083] The U-shaped yoke may be provided with a shoulder at its open end to provide the open end attachment surface. The shoulder may be an annular groove formed at the open end of the U-shaped yoke.

[0084] Preferably, the U-shaped yoke includes a base end attachment surface at the base end, where the inner circumference of the distal suspension connecting the frame and the magnet unit is attached to the base end attachment surface of the magnet unit.

[0085] The U-shaped yoke may be provided with a shoulder at its base end to provide the base end attachment surface. The shoulder may be an annular groove formed at the base end of the U-shaped yoke.

[0086] The vibrator can be divided into a proximal side and a distal side by a middle plane perpendicular to the movement axis and passing through the voice coil winding (when the vibrator is stationary), where the proximal side of the vibrator is the side where the middle plane includes the voice coil bobbin attachment surface, and the distal side is the other side of the middle plane.

[0087] To avoid any doubt, the middle plane can be located at any position on the movement axis as long as it passes through the voice coil and does not lie at the end of the vibrator.

[0088] Preferably, the proximal suspension is located on the proximal side of the vibrator, and the distal suspension is located on the distal side. This helps to suppress the rocking motion when the vibrator is in use. The base end attachment surface of the U-shaped yoke can be located on the distal side of the vibrator, and the open end attachment surface can be located on the proximal side. However, other arrangements are also possible.

[0089] The application device attachment surface can be located on the proximal side or the distal side of the intermediate plane, or can even be located on the intermediate plane, as the application device attachment surface typically varies according to the application device.

[0090] The frame can include a main frame and a sub-frame connected together, where the main frame includes the application device attachment surface.

[0091] The main frame can include at least one distal suspension attachment surface for connecting a distal suspension. The at least one distal suspension attachment surface can be provided by one or more slots in the main frame, each slot corresponding to a respective attachment tab on the outer periphery of the distal suspension, where one or more attachment tabs facilitate a mechanical connection of the distal suspension to the main frame through a bayonet connection, and where the attachment tabs engage with the corresponding slots in the frame when attaching the suspension to the frame. In such an arrangement, the distal suspension is preferably another (e.g., metal) suspension (rather than a suspension including an elastomeric material).

[0092] The sub-frame can include a voice coil bobbin attachment surface.

[0093] The main frame and / or the sub-frame can include at least one proximal suspension attachment surface for connecting the outer periphery of a proximal suspension. In some embodiments, both the main frame and the sub-frame can include at least one proximal suspension attachment surface for connecting the outer periphery of a proximal suspension, where the outer periphery of the proximal suspension is clamped between at least one proximal suspension attachment surface of the main frame and at least one proximal suspension attachment surface of the sub-frame.

[0094] The dust cover can be part of the sub-frame, e.g., the dust cover can be attached to another frame element to form the sub-frame. The dust cover can be configured to prevent dust from entering the U-shaped yoke of the magnet unit.

[0095] The voice coil can include at least two layers, preferably at least four layers (i.e., the wire forming the voice coil can be wound around the voice coil bobbin to form at least two layers of coils), as this helps to improve the performance of the vibrator.

[0096] The air gap can extend around the movement axis.

[0097] The frame (preferably the sub-frame) can include one or more channels, where each channel is for guiding the wire of the voice coil out of the vibrator.

[0098] One of the proximal suspension and the distal suspension can be airtight, where the airtight suspension and the frame are configured together to contain an air volume for resisting the movement of the magnet unit along the movement axis when the vibrator is activated. The advantages of such an arrangement will be discussed below in connection with the third aspect of the present invention.

[0099] The vibrator according to the first aspect may include any one or more of the features described in the third aspect (e.g., regarding air volume, airtight suspension, one or more ventilation holes, and / or the material covering the ventilation holes).

[0100] For example, the airtight suspension may be a proximal suspension and the other suspension may be a distal suspension. In such examples, the airtight suspension may form a seal that substantially prevents airflow through it.

[0101] In other examples, the airtight suspension may be a distal suspension and the other suspension may be a proximal suspension. In such examples, the airtight distal suspension may form a seal that substantially prevents airflow through it.

[0102] For example, the airtight suspension and the frame may be configured to provide a predetermined damping effect on the movement of the magnet unit. The airtight suspension and the frame may be configured to provide the resonant frequency Fs required for the vibrator.

[0103] For example, the frame and / or the magnet unit may include one or more ventilation holes for allowing air to be exhausted from or enter the air volume, and these ventilation holes may optionally be covered with a material having a specific airflow resistance. In this way, the flow of air in and out of the air volume can be controlled to damp the movement of the magnet unit. The inventors have found that by using ventilation holes and an optional covering material to damp the movement of the magnet unit, the resonant frequency of the vibrator can be reduced compared to when the air volume is completely sealed.

[0104] For example, each ventilation hole may be (respectively) covered with a material having a specific airflow resistance to provide a predetermined resistance to the air being exhausted from or entering the air volume. For example, the material covering the ventilation holes may be fabric, felt, foam element, paper, or any other suitable microporous material having a specific airflow resistance. The airflow resistance of the material covering the ventilation holes may be in the range of 0 to 5000 Pa.s / m, more preferably in the range of 50 Pa.s / m to 2500 Pa.s / m. This helps to provide a controlled amount of damping for the magnet unit and to provide the required resonant frequency for the vibrator. This effect is described in more detail in relation to Figure 22 and Figure 23 the description of.

[0105] For example, the airflow resistance of the material covering the ventilation holes may be from 0 to 5000 Pa.s / m, preferably from 50 Pa.s / m to 2500 Pa.s / m.

[0106] For example, the volume of the air volume may be in the range of 5 cm 3 to 30 cm 3 and preferably from 10 cm 3 to 20 cm3 .

[0107] For example, the surface area of the part configured to move within the air volume in the magnet unit can be in the range of 3 cm 2 to 50 cm 2 and preferably in the range of 8 cm 2 to 20 cm 2 .

[0108] In a second aspect, the present invention can provide a device comprising:

[0109] a vibrator according to the first aspect;

[0110] an application device, wherein the vibrator is attached to the application device through an attachment surface of the application device.

[0111] The application device can be a seat, such as a vehicle seat. In an example, the vibrator can be attached to the seat (such as a vehicle seat) through the frame of the vehicle seat, the foam in the seat, or a rigid panel in the seat, where the rigid panel can form the soundboard of the vibrator.

[0112] The application device can be an acoustic panel, which is configured to generate sound when the vibrator is activated by supplying current to the voice coil. As is well known in the art, an acoustic panel typically has high stiffness and is appropriately damped to generate sound during audio-frequency vibration.

[0113] In a third aspect, the present invention can provide: a vibrator for transmitting vibration to an application device, the vibrator having:

[0114] a frame including an attachment surface for attaching the vibrator to the application device;

[0115] a magnet unit configured to provide a magnetic field in an air gap;

[0116] a coil assembly including a voice coil mounted on a voice coil bobbin, where the voice coil bobbin is attached to the frame at a voice coil bobbin attachment surface on the frame, and where the voice coil bobbin is configured to position the voice coil in the air gap when the vibrator is stationary;

[0117] wherein when the vibrator is activated by supplying current to the voice coil, the magnet unit is configured to move relative to the voice coil along the movement axis of the vibrator;

[0118] wherein the magnet unit is suspended from the frame by a suspension device, the suspension device including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, and the proximal suspension is closer to the voice coil bobbin attachment surface on the frame than the distal suspension when the vibrator is stationary;

[0119] One of the proximal suspension and the distal suspension is an airtight suspension, and the airtight suspension and the frame are jointly configured to include an air volume for resisting the movement of the magnet unit along the movement axis when the vibrator is activated.

[0120] In this way, the air volume can protect the proximal and distal suspensions by reducing the stress on the suspensions, reducing the fatigue of the suspensions and improving the durability of the vibrator.

[0121] In addition, the air volume can be regarded as providing additional stiffness, superimposed on the stiffness already provided by the proximal and distal suspensions. The stiffness introduced by the air volume can reduce the situation of the vibrator "bottoming out", that is, the magnet unit contacts the frame or the voice coil when reaching the maximum displacement. Therefore, the vibrator can operate at a higher peak voltage without generating abnormal noise and noise artifacts due to bottoming out.

[0122] In addition, by changing the size and other characteristics of the air volume, the amount of stiffness provided by the air volume can be adjusted, thereby adjusting the resonant frequency of the vibrator, without having to redesign or replace the suspension or other moving parts for a new application device. For example, as described in detail below, vent holes covered with materials having a specific air flow resistance can be provided in the frame and / or the magnet unit to further adjust the resonant frequency of the vibrator, thereby damping the movement of the magnet unit.

[0123] By making one of the proximal suspension and the distal suspension an airtight suspension, when the airtight suspension and the magnet unit move towards the air volume, the air in the air volume may be compressed. Therefore, the compressed air can resist the movement of the magnet in the first direction (towards the air volume). When the airtight suspension and the magnet unit move away from the air volume in the second direction, the air volume can also provide negative pressure (i.e., suction). Therefore, the negative pressure resists the movement of the magnet in the second direction. In this way, the air volume can act as an air cushion as a third suspension, providing additional stiffness to affect the movement of the magnet unit when it moves in the first and second directions.

[0124] To avoid any doubt, the air volume can further be included by the magnet unit (in addition to the frame and the airtight suspension).

[0125] In this article, the other of the proximal suspension and the distal suspension (i.e., the suspension that is not the airtight suspension) can be simply referred to as the "other" suspension (for the third aspect of the present invention).

[0126] The other suspension can be a metal suspension, that is, made of metal. According to the design requirements, by giving it an appropriate geometry, the metal suspension can be configured to dominate or not dominate the overall stiffness of the suspension device, thus helping to meet the stiffness requirements described herein.

[0127] The metal suspension can be made of a metal plate. In some examples, the thickness of the metal plate can be 1 mm or less. The metal suspension can be a leaf spring configured to bend when the magnet unit moves relative to the voice coil along the movement axis.

[0128] The metal suspension can have one or more cuts to facilitate proper behavior. One or more cuts can have a spiral shape.

[0129] The metal suspension can be annular and positioned to extend circumferentially around the magnet unit.

[0130] Thus, the metal suspension can include one or more (preferably multiple, preferably at least three) attachment tabs located on its outer periphery, where one or more attachment tabs facilitate the mechanical connection of the distal suspension to the frame. More preferably, the frame includes one or more slots, each slot corresponding to a respective attachment tab on the outer periphery of the metal suspension, where one or more attachment tabs facilitate the mechanical connection of the distal suspension to the frame through a bayonet connection, where the attachment tabs engage with the corresponding slots in the frame. This helps with accurate positioning when attaching the metal suspension to the frame.

[0131] In other examples, another suspension can be made of plastic configured to bend when the magnet unit moves relative to the voice coil along the movement axis. In other examples, another suspension can be made of rubber or fabric. In some examples, the stiffness of such a rubber or fabric suspension can be higher (or lower) than that of an airtight suspension, for example, according to design requirements.

[0132] In some examples, the airtight suspension can be the proximal suspension and another suspension can be the distal suspension. In such examples, the airtight suspension can form a seal that substantially prevents air flow through.

[0133] In other examples, the airtight suspension can be the distal suspension and another suspension can be the proximal suspension. In such examples, the airtight distal suspension can form a seal that substantially prevents air flow through.

[0134] The airtight suspension and the frame can be configured to provide a predetermined damping effect on the movement of the magnet unit. The airtight suspension and the frame can be configured to provide the resonant frequency Fs required for the vibrator.

[0135] For example, by appropriately adjusting the size of the air volume, the airtight suspension and the frame can be configured to provide the resonant frequency Fs required for the vibrator. In this way, the compliance (equal to the reciprocal of the air volume stiffness) of the air volume can be increased or decreased to adjust the maximum displacement of the magnet unit and the resonant frequency of the vibrator.

[0136] Therefore, the stiffness of the air volume can be adjusted by adjusting the overall shape of the magnet unit, thereby adjusting the surface area of the portion of the magnet unit configured to move within the air volume to resist the movement of the magnet unit.

[0137] The frame and / or the magnet unit may include one or more ventilation holes for discharging or admitting air into the air volume, wherein each ventilation hole may optionally be covered with a material having a specific air flow resistance. In this way, the flow of air into and out of the air volume can be controlled to damp the movement of the magnet unit. The inventors have found that by using ventilation holes and an optional covering material to damp the movement of the magnet unit, the resonant frequency of the vibrator can be reduced compared to a completely sealed air volume.

[0138] Each ventilation hole may be separately covered with a material having a specific air flow resistance to provide a predetermined resistance to the discharge and admission of air into the air volume. For example, the material covering the ventilation hole may be fabric, felt, foam element, paper or any other suitable micro-perforated material having a specific air flow resistance. The specific air flow resistance of the material covering the ventilation hole may be in the range of 0 to 5000 Pa.s / m, more preferably in the range of 50 Pa.s / m to 2500 Pa.s / m. This helps to provide a controlled amount of damping for the magnet unit and the required resonant frequency for the vibrator. This effect is described in more detail in connection with Figure 22 and Figure 23 the description.

[0139] To avoid any doubt, if there are multiple ventilation holes, each ventilation hole does not need to be covered with the same material or the same piece of material. For example, different ventilation holes may be covered with different materials having different air flow resistances. However, it is preferred that each ventilation hole is separately covered with a material having an air flow resistance in the range of 0 to 5000 Pa.s / m (more preferably in the range of 50 Pa.s / m to 2500 Pa.s / m).

[0140] The airtight suspension, the frame and, if included, the material covering one or more ventilation holes may be configured to provide a predetermined damping effect and / or the required resonant frequency, for example by changing the size or number of ventilation holes in the frame and / or the magnet unit, and / or by changing the material covering the ventilation holes, for example to meet one or more design requirements as needed.

[0141] For example, to reduce the amount of damping provided by the air volume, larger or more ventilation holes may be provided to reduce the restriction of air entering and leaving the air volume. To increase the amount of damping, fewer or smaller ventilation holes may be provided to restrict the passage of air into and out of the air volume. In some examples, the ventilation holes may include valves that the vibrator can tune by opening or closing the valves.

[0142] In other examples, the damping amount provided by the air volume can be increased by covering the specific airflow resistance of the vent material to restrict the passage of air in and out of the air volume. The damping amount provided by the air volume can be reduced by decreasing the specific airflow resistance of the vent material to facilitate the flow of air in and out of the air volume.

[0143] One or more vents can be provided in a portion of the frame (such as a sub-frame) that includes a voice coil bobbin attachment surface. A material having a predetermined specific airflow resistance can be provided in the form of a cover to cover one or more vents in this portion of the frame. In this way, a sufficient amount of air can be configured to flow in and out of the air volume to provide the desired damping level for the magnet unit.

[0144] Alternatively or additionally, one or more vents can be provided on the side of the frame at a position along the axis of movement of the vibrator, between the voice coil bobbin attachment surface and the airtight suspension. One or more vents can be covered with a material having a specific airflow resistance. In some examples, the material can be a foam plug. Providing the vents on the side of the frame is very useful for applications where the airflow in and out of the vents on the voice coil bobbin attachment surface may be blocked. Therefore, the vibrator can be installed in a more confined space while still achieving high performance.

[0145] In other examples, one or more vents can be provided as openings in the magnet unit, such as leading to the rear of the vibrator. The openings in the magnet unit can be covered with a material having a specific airflow resistance to adjust the damping effect of the air volume and the resonant frequency of the vibrator. This arrangement is very useful for vibrators installed in applications where the space around the air volume may be limited.

[0146] The airflow resistance of the material covering each vent can be from 0 to 5000 Pa.s / m, preferably from 50 Pa.s / m to 2000 Pa.s / m.

[0147] The volume of the air volume can be in the range of 5 cm 3 to 30 cm 3 , preferably from 10 cm 3 to 20 cm 3 .

[0148] The surface area of the portion of the magnet unit configured to move within the air volume can be in the range of 3 cm 2 to 50 cm 2 , preferably from 8 cm 2 to 20 cm 2 .

[0149] Preferably, one of the proximal suspension and the distal suspension includes an elastomeric material configured to elastically stretch such that the stiffness of the suspension including the elastomeric material increases as the magnet unit moves away from the rest position along the movement axis.

[0150] If one of the proximal suspension and the distal suspension includes an elastomeric material, the airtight suspension is preferably also the suspension including the elastomeric material. In such an arrangement, the airtight suspension is preferably also the proximal suspension. This is a particularly elegant way of combining an elastic suspension and an air volume into the same vibrator. However, it is also possible that the other suspension (i.e., the suspension that is not the airtight suspension) is the suspension including the elastomeric material, and / or the airtight suspension is the distal suspension.

[0151] In an example where one of the proximal suspension and the distal suspension includes an elastomeric material (e.g., an example where the airtight suspension includes an elastomeric material), any one or more of the features described in the first aspect of the present invention can be used in combination with the vibrator according to the third aspect of the present invention.

[0152] For example, the airtight suspension can be made entirely of an airtight elastomeric material, such as rubber.

[0153] For example, the suspension including the elastomeric material (which can also be the airtight suspension) can be a coiled suspension.

[0154] Preferably, one of the proximal suspension and the distal suspension has a stiffness K1 and the other has a stiffness K2, where K2 > K1 when the vibrator is at rest, i.e., when the vibrator is at rest, the stiffness K2 of one of the proximal suspension and the distal suspension is greater than the stiffness K1 of the other.

[0155] In such examples, the proximal suspension or the distal suspension having the stiffness K2 herein can be referred to as the "main" or "dominant" suspension, and the other having the stiffness K1 can be referred to as the "secondary" or "non - dominant" suspension.

[0156] The ratio K1 / K2 is preferably 0.4 or less (when the vibrator is at rest). The advantages of this configuration are described in the extract of GB2108925.5 provided as an appendix.

[0157] In some examples, the airtight suspension can have a stiffness K1 (when the vibrator is at rest), while the other (e.g., metal) suspension has a stiffness K2 (when the vibrator is at rest). In other examples, the airtight suspension can have a stiffness K2 (when the vibrator is at rest), while the other (e.g., metal) suspension has a stiffness K1 (when the vibrator is at rest).

[0158] Any feature related to the first aspect of the present invention or described in the appendix related to a suspension with stiffness K1 and / or a suspension with stiffness K2 may optionally be used in combination with the third aspect of the present invention, unless it is clearly not allowed or explicitly avoided.

[0159] For example, the stiffness K1 may be 0.1 N / mm or higher, preferably 0.2 N / mm or higher, more preferably 0.4 N / mm or higher (when the vibrator is stationary).

[0160] For example, the stiffness K1 may be 20 N / mm or lower, preferably 10 N / mm or lower (when the vibrator is stationary).

[0161] For example, K1 may be in the range of 0.4 N / mm to 10 N / mm (when the vibrator is stationary).

[0162] For example, K1 may be in the range of 2 N / mm to 50 N / mm (when the vibrator is stationary).

[0163] For example, the stiffness K2 may be 1 N / mm or higher, preferably 2 N / mm or higher (when the vibrator is stationary).

[0164] For example, the stiffness K2 may be 100 N / mm or lower, preferably 50 N / mm or lower (when the vibrator is stationary).

[0165] For example, K2 may be in the range of 1 N / mm to 100 N / mm (when the vibrator is stationary).

[0166] For example, the mass of the magnet unit may be 40 g or more.

[0167] For example, the suspension with stiffness K2 may be annular and positioned to extend circumferentially around the magnet unit.

[0168] For example, the ratio K1 / K2 may be 0.35 or less (when the vibrator is stationary). The ratio K1 / K2 may be 0.3 or less, even 0.25 or less (when the vibrator is stationary). The lower the ratio K1 / K2 when the vibrator is stationary, the more dominant the suspension with stiffness K2 is in providing the stiffness of the suspension device.

[0169] For example, the proximal suspension may have a stiffness K1 and the distal suspension may have a stiffness K2. In other examples, the proximal suspension may have a stiffness K2 and the distal suspension may have a stiffness K1.

[0170] The inventor has found that it is particularly advantageous to use a metal suspension as the suspension with stiffness K2 and, in combination, an airtight suspension (preferably also including an elastic material) as the suspension with stiffness K1 in providing a vibrator that resists rocking motion, is easy to manufacture, and has a resonance frequency that is stable over time.

[0171] In a fourth aspect, the present invention can provide a device including:

[0172] A vibrator according to the third aspect;

[0173] An application device, wherein the vibrator is attached to the application device through an attachment surface of the application device.

[0174] The application device can be a seat, such as a vehicle seat. In an example, the vibrator can be attached to the seat (such as a vehicle seat) through the frame of the vehicle seat, the foam in the seat, or a rigid panel in the seat, where the rigid panel can form the soundboard of the vibrator.

[0175] The application device can be an acoustic panel configured to produce sound when the vibrator is activated by supplying current to the voice coil. As is well known in the art, acoustic panels typically have high stiffness and are appropriately damped to produce sound when vibrating at audio frequencies.

[0176] In an additional aspect of the present invention, a method of configuring a vibrator according to the third aspect of the present invention can be provided.

[0177] The method can include adjusting the size, number, or type of material covering the ventilation holes (such as in the frame) of one or more ventilation holes to provide a predetermined damping effect on the movement of the magnet unit or the resonance frequency required for the vibrator (such as to meet the criteria described herein, such as regarding the resonance frequency of the vibrator).

[0178] The present invention includes combinations of the above aspects and preferred features, unless such combinations are clearly not permitted or are explicitly avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0179] The following will discuss various embodiments and experiments that illustrate the principles of the present invention in conjunction with the drawings, where:

[0180] Figure 11 A cross-section of an exemplary vibrator is shown;

[0181] Figure 12 A cross-section of another exemplary vibrator is shown;

[0182] Figures 13A to 13B A cross-section of another exemplary vibrator is shown;

[0183] Figures 14A to 14B An exploded view and a perspective view of another exemplary vibrator are shown;

[0184] Figures 15A to 15B Shows an exploded view and a perspective view of another exemplary vibrator;

[0185] Figure 16 Shows a cross-section of another exemplary vibrator;

[0186] Figures 17 to 28 Shows the experimental results. Detailed Description

[0187] Aspects and embodiments of the present invention will be discussed below in conjunction with the accompanying drawings. Other aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated herein by reference.

[0188] In the following examples, similar features have been given corresponding reference numerals and the corresponding descriptions may also apply, unless clearly not permitted or explicitly avoided.

[0189] Figure 11 Shows a cross-section of an exemplary vibrator 400 for transmitting vibration to an application device.

[0190] The vibrator 400 includes a frame 410, a magnet unit 430, and a coil assembly 420.

[0191] The frame 410 is formed by a main frame 412 and a sub-frame 414, and includes an application device attachment surface for attaching the vibrator 400 to an application device.

[0192] In this example, the attachment surface is provided by a plurality of attachment structures 412a ( Figure 11 one of which is visible in

[0193] ), which are configured to receive screws to attach the vibrator to the application device (thus, the application device surface can be regarded as the internal thread of the attachment structure 412a, which is used in use to facilitate such attachment).

[0194] The magnet unit 430 of the vibrator 400 includes a U-shaped yoke 434, a magnet 436, and a spacer 438. The shape of the magnet unit 430 provides an annular air gap 432, and the magnet unit 430 provides a magnetic field in the air gap.

[0195] The coil assembly 420 includes a voice coil 422 mounted on a voice coil bobbin 424. The voice coil bobbin 424 is attached to the frame 410 at a voice coil bobbin attachment surface 418 on the frame 410, and is configured to position the voice coil 422 in the air gap 432 when the magnet unit 430 is in the rest position and the vibrator 400 is stationary.

[0196] In use, an electric current is supplied to the voice coil 422 such that a magnetic field is generated by the voice coil, and this magnetic field interacts with the magnetic field provided by the magnet unit 430 (in the air gap 432). This causes the magnet unit 430 to move relative to the voice coil 422 along the movement axis 402 of the vibrator 400. Of course, the movement of the magnet unit 430 relative to the voice coil 422 along the movement axis 402 can also be regarded as the movement of the voice coil 422 relative to the magnet unit 430.

[0197] The magnet unit 430 is suspended from the frame 410 by a suspension device, which includes a proximal suspension 440 and a distal suspension 442. The proximal suspension 440 connects the frame 410 and the magnet unit 430, and the distal suspension 442 connects the frame 410 and the magnet unit 430. The proximal suspension 440 is closer to the voice coil bobbin attachment surface 418 on the frame than the distal suspension 442.

[0198] In this example, the proximal suspension 440 and the distal suspension 442 are attached to a U-shaped yoke 434 of the magnet unit 430. The U-shaped yoke 434 is U-shaped when viewed in cross-section, and includes an annular proximal attachment surface for the proximal suspension 440 at the open end of the U-shaped yoke 434 and an annular distal attachment surface for the distal suspension 442 at the base end of the U-shaped yoke.

[0199] In this example, the proximal suspension 440 is connected to the frame 410 by being clamped between a main frame 412 and a sub-frame 414 and glued to the main frame 412 and the sub-frame 414.

[0200] The proximal suspension 440 and the distal suspension 442 are configured to have different stiffnesses. In this example, the distal suspension 442 has a stiffness K2, and the proximal suspension 440 has a stiffness K1, where K1 < K2. The total stiffness of the suspension device can be expressed as K t = K1 + K2.

[0201] For example, when the vibrator 400 is stationary, the ratio K1 / K2 can be 0.4 or less. Thus, in this example, the main stiffness of the suspension device when the vibrator 400 is stationary is provided by the distal suspension 442. The K2 suspension can be regarded as the dominant suspension in the suspension device. The K1 suspension can be called the secondary suspension, and the K2 suspension can be called the primary suspension.

[0202] In this example, the distal (K2) suspension 442 is a metal suspension. The shown metal suspension 442 has a flat (i.e., sheet-like) configuration and includes cutouts, but other configurations can also be used depending on the material employed. However, the distal suspension 442 can have different configurations. For example, the distal suspension 442 can be one of the different metal suspension configurations described in the appendix regarding Figure 10A and 10B The metal suspension 442 can be made of steel, such as tempered stainless steel, like AISI 301.

[0203] In this example, the distal suspension 442 is attached to the main frame 412 by a bayonet connection, where the attachment tab 444 of the distal suspension 442 engages with the slot 413 of the main frame 412. The attachment tab 444 of the distal suspension 442 is glued to the slot 413 of the main frame 422 when fully inserted into the slot to ensure attachment and add some damping effect.

[0204] In this example, the proximal (K1) suspension 440 is made of an elastomeric material (such as rubber), which is configured to elastically stretch such that the stiffness K1 increases as the magnet unit 430 moves away from the rest position along the movement axis 402.

[0205] In this example, the proximal (K1) suspension 440 is made of an airtight material because it is made of an airtight elastomeric material. Here, the proximal suspension with stiffness K1 together with the frame 410 encloses an air volume 443 for resisting the movement of the magnet unit 430 along the movement axis 402 when the vibrator 402 is activated.

[0206] In this example, the proximal (K1) suspension 440 is a suspension made of rubber in the form of a flat disk circumferentially extending around the magnet unit 430.

[0207] When the proximal suspension 440 and the magnet unit 430 move towards the air volume 443, the air within the air volume 443 can be compressed. Thus, the compressed air can resist the movement of the magnet in the first direction (towards the air volume 443). When the proximal suspension 440 and the magnet unit 430 move away from the air volume 443 in the second direction, the air volume 443 can also exert a negative pressure (i.e., suction force) on the magnet unit 430. In this way, the air volume 443 can act as an air cushion, which serves as a third suspension to provide additional stiffness to affect the movement of the magnet unit 430 when it moves in the first and second directions.

[0208] The air volume 443 can protect the proximal suspension 440 and the distal suspension 442 by reducing the stress on the suspension, reducing the fatigue of the suspension device and improving the durability of the vibrator 400. In addition, by changing the size and acoustic impedance of the air volume 443, the resonant frequency of the vibrator 400 and / or the damping amount provided by the air volume 443 can be adjusted without redesigning or replacing the suspension or other moving parts for a new application device.

[0209] Preferably, as will be exemplified in more detail below, the frame 410 may include one or more ventilation holes for allowing air to escape from and enter the air volume 443, and these ventilation holes are covered with a material having a specific air flow resistance in order to tune the resonant frequency of the vibrator 400 without changing the size / shape of the air volume 443. The vibrator with ventilation holes will be described in more detail below in connection with FIGS. 14a to 15b.

[0210] In other examples, the air volume 443 may be sealed (i.e., without ventilation holes), in which case the volume of the air volume 443 is preferably larger (e.g., 20 - 30 cm 3 ), and the radiator is relatively smaller (e.g., 8 - 10 cm 3 ) to obtain the maximum benefit from the air volume 443 (as discussed in Experimental Data II). Here, the "radiator" refers to the surface area of the magnet unit and a part of the suspension, which is configured to move in the air volume and is responsible for regulating the air pressure in the air volume.

[0211] In other examples, the air volume 443 may not be used to provide additional stiffness, for example, by adding large holes or slots in the proximal (K1) suspension 440, or by making the proximal (K1) suspension 440 containing an elastomeric material a breathable material. In these examples, air can freely pass in and out of the air volume 443 through the proximal (K1) suspension 440, that is, the air volume does not resist the movement of the magnet unit 430 along the movement axis 402.

[0212] In one example, the application device may be a seat frame of a vehicle seat, which has an attachment structure with screw holes, allowing the attachment structure on the vehicle seat to be connected to the attachment structure 412a on the vibrator 400 using screws.

[0213] Figure 12 A cross-section of another exemplary vibrator 500 including a frame 510, a magnet unit 530, and a coil assembly 520 is shown.

[0214] Figure 12 The vibrator in Figure 11 has features corresponding to those of the

[0215] vibrator, and corresponding reference numerals have been given. Figure 11 The difference from theFigure 12 The proximal (K1) suspension 540 in Figure 12 is a coiled suspension having a shallow single - coil geometry. Here, the proximal suspension 540 extends circumferentially around the magnet unit 530 and is formed by two concentric flat portions connected by a curved portion when viewed in a plane containing the movement axis 502. In particular, the curved portion forms a single coil when viewed in a plane containing the movement axis 502.

[0216] By including the coiled geometry in the proximal suspension 540, the manufacturing tolerances when positioning the magnet unit 530 in the vibrator 500 can be increased. Additionally, the coiled geometry can reduce the stress borne at the connection between the proximal suspension 542 and the magnet unit 530. The coiled geometry will introduce asymmetry and / or non - linearity into the stiffness provided by the proximal suspension 540 (as described below with respect to Figure 15b).

[0217] Preferably, the coiled geometry of the suspension 540 is shallow because this helps to minimize the asymmetry of the stiffness K1 of the proximal suspension 540 (compared to using a deep coiled geometry), while ensuring that the suspension 540 stretches within the displacement range of the magnet unit 530. If the coiled geometry of the suspension 540 is too large, the suspension 540 will not stretch within the displacement range of the magnet unit 530, the stiffness of the suspension 540 will be more linear with respect to displacement, and the useful resonance frequency Fs shift achieved as the displacement increases (discussed in more detail below) will not be realized. Preferably, the shallow coiled geometry of the suspension 540 is configured such that the stiffness of the suspension 540 is at least twice that at the rest position when the magnet unit 530 is at its maximum (positive or negative) displacement.

[0218] Figure 12 The shallow coiled geometry is depicted by the parameters "W" and "h". The parameter "W" represents the width of the unclamped portion of the proximal (coiled) suspension 540 (i.e., the portion of the proximal (coiled) suspension 540 that is not clamped or bonded to the magnet unit 530 or the frame 510), measured in a direction perpendicular to the movement axis 502 in a plane containing the movement axis 502 when the vibrator 500 is at rest. As Figure 12 shown, the width W extends from the magnet unit 530 (specifically, the U - shaped yoke 534 of the magnet unit 530) to the inner surface of the frame 510 and corresponds to the outer perimeter of the unclamped portion of the proximal suspension 540 (on the same side of the movement axis 502). The parameter "h" represents the maximum extent of the proximal (coiled) suspension 540 along the movement axis, measured when the vibrator 500 is at rest. Preferably, "h" does not exceed 40% of "W", more preferably does not exceed 30%, and most preferably does not exceed 20% to mitigate the asymmetry of the stiffness of the proximal (K1) suspension 540 (compared to using a deep coiled geometry). In this example, "W" is 5.7 mm and "h" is 0.97 mm.

[0219] Figure 13A A cross-section of another exemplary vibrator 600 including a frame 610, a magnet unit 630, and a coil assembly 620 is shown. FIG. 13b shows a close-up view of the proximal suspension 640.

[0220] Figures 13A to 13B The vibrator 600 in [reference] has the same features as Figure 12 the vibrator 500. However, in this example, the proximal (K1) suspension 640 is attached to the magnet unit 630 by an attachment ring 641.

[0221] The attachment ring 641 is attached to the proximal (K1) suspension 640 at the inner circumference of the proximal (K1) suspension 640 and extends circumferentially around the magnet unit 630. The attachment ring 641 is made of plastic (such as PC, PC-ABS, PP). However, in some examples, the attachment ring 641 can be made of different materials, such as metal or fabric.

[0222] The attachment ring 641 is attached to the proximal (K1) suspension 640 and the magnet unit 630, for example, by glue. In other examples, the attachment ring 641 can be injection molded onto the magnet unit 630 and attached to the proximal (K1) suspension by glue. Using the attachment ring 641 to attach the proximal (K1) suspension 640 to the magnet unit 630 can be more convenient and cost-effective because more conventional glue can be used to attach the attachment ring 641 to the magnet unit 630 instead of requiring glue specifically designed to bond with the elastomeric material in the proximal (K1) suspension 640. In addition, the attachment ring 641 can make the suspension 640 easier to handle and position for attachment to the magnet unit 630 during the assembly of the vibrator 600. Furthermore, changes in the way the suspension 640 is attached to the U-shaped yoke surface can result in changes in the stiffness and damping performance of the suspension 640. The attachment ring 641 helps offset these changes by providing a more consistent connection method for the suspension 640, thereby improving the performance consistency of the vibrator 600.

[0223] Figure 14A An exploded view of another exemplary vibrator 700 including a frame 710, a magnet unit, and a coil assembly is shown. FIG. 14b shows an assembled view of the vibrator 700 of FIG. 14a. Note that in FIGS. 14a to 14b, the vibrator 700 is inverted relative to Figure 11 FIGS. 13, so the proximal suspension 740 is at the top of the vibrator 700 in FIGS. 14a to 14b, and the distal suspension (obscured by the frame 710) is at the bottom of the vibrator 700.

[0224] Figures 14A to 14B The vibrator 700 in [reference] includes Figure 12All features of the vibrator 500, including the proximal (K1) suspension 740, which is a coiled suspension and made of airtight material. However, in this example, the frame 710 includes ventilation holes 717 for allowing air to escape from and enter the air volume contained in the proximal suspension 740 and the frame 710. The ventilation holes 717 are covered with a material having a specific airflow resistance to provide a predetermined resistance to the escape and entry of air from the air volume. In this way, the flow of air in and out of the air volume can be controlled to define the mechanical stiffness and damping provided by the air volume and the material for resisting the movement of the magnet unit. In addition, the use of the ventilation holes 717 and the covering material helps to tune the resonant frequency of the vibrator 400 without changing the size / shape of the air volume.

[0225] In Figures 14A to 14B the example, the ventilation holes 717 are provided at the end of the frame 710 that includes the voice coil bobbin attachment surface.

[0226] The material covering the ventilation holes 717 can be a fabric, felt, foam element, paper, or any other suitable microporous material having a specific airflow resistance. In this example, the material having a predetermined specific airflow resistance is provided in the form of a covering 718 to cover the ventilation holes 717 in this part of the frame 710.

[0227] Figure 15A An exploded view of another exemplary vibrator 800 including a frame 810, a magnet unit, and a coil assembly is shown. Figure 15b shows an assembled view of the vibrator 800 of Figure 15a.

[0228] In Figures 15A to 15B it, the ventilation holes 817 are provided on the side of the frame 810 at a position along the movement axis of the vibrator, between the voice coil bobbin attachment surface and the proximal suspension 840.

[0229] In this example, the ventilation holes 817 are covered with a foam plug 821 having a specific airflow resistance to provide a predetermined resistance to the escape and entry of air from the air volume. Providing the ventilation holes 817 on the side of the frame 810 is very useful for applications where the air flow in and out of the ventilation holes on the voice coil bobbin attachment surface may be blocked. Therefore, the vibrator 800 can be installed in a more confined space while still achieving high performance.

[0230] In other examples, the ventilation holes can be provided as openings in the magnet unit. This arrangement is very useful for vibrators installed in applications where the space around the air volume may be limited.

[0231] Figure 16 A cross-section of another exemplary vibrator 900 including a frame 910, a magnet unit 930, and a coil assembly 920 is shown.

[0232] In this example, the proximal suspension 940 is a fabric suspension, i.e., made of a fabric that does not contain an elastomeric material. The proximal suspension includes corrugations that extend circumferentially around the magnet unit.

[0233] In this example, the proximal (K1) suspension is made of an airtight fabric, and thus together with the frame 910, the proximal suspension 940 encloses an air volume 941 that resists the movement of the magnet unit 930 along the movement axis 902 when the vibrator 900 is activated.

[0234] The frame 910 is provided with ventilation holes 919 for allowing air to enter and exit the air volume. The ventilation holes are covered by a foam plug 921 having a specific airflow resistance to provide a predetermined resistance to the escape and entry of air from the air volume 941. The foam plug 921 is located on the frame 910 between the ventilation hole 919 and the air outlet 919 on the side of the frame 910.

[0235] In this example, the proximal and distal suspensions of the vibrator (as described in the appendix) according to GB2108925.5 provide damping to the magnet unit, and the air volume acts as a third suspension to provide an additional damping effect to the movement of the magnet unit 932.

[0236] In Figure 16 In other variants of the example (not shown), the corrugated proximal suspension 940 can be made of an elastomeric material such as rubber. In such examples, the presence of the corrugations can cause the suspension to act similarly to a conventional fabric suspension, where the corrugations are configured to straighten and bend as the magnet unit moves relative to the movement axis, i.e., without stretching. Thus, in such examples, even if the proximal suspension 940 is made of an elastomeric material, its stiffness does not increase as the magnet unit moves away from the rest position along the movement axis 902, but if the elastic suspension is airtight, the vibrator will still benefit from the air volume 941 resisting the movement of the magnet unit 930 along the movement axis 902 when the vibrator is activated.

[0237] Experimental data

[0238] The following discussion provides experimental data and supporting explanations that will help the reader better understand the present invention. Any theoretical explanations provided herein are for enhancing the reader's understanding, and the inventors do not wish to be bound by these theoretical explanations.

[0239] Experimental Data I

[0240] Figure 17 Shows how the restoring forces (in Newtons) of the distal and proximal suspensions vary with the displacement of the magnet unit from the rest position. The dashed line shows the variation of the restoring force of a vibrator having a fabric proximal suspension according to GB2108925.5 (as described in the appendix). The solid line shows the variation for a vibrator having a Figure 12Variation of the restoring force of the vibrator of the exemplary proximal suspension 540 (including elastomeric material). The proximal suspension 540 including elastomeric material is a coiled suspension made of rubber, as Figure 12 shown.

[0241] Figure 17 The dashed line in

[0242] shows that the force exerted by the fabric suspension is substantially constant within the typical displacement range of the suspension in the vibrator (i.e., between -2 mm and 2 mm). When the displacement exceeds ±2 mm, the restoring force of the fabric suspension increases rapidly until the fabric suspension begins to tear, at which point the restoring force drops rapidly after the displacement exceeds 6 mm. Figure 17 In contrast,

[0243] Figure 18A the solid line in Figure 18A shows that the restoring force (i.e., stiffness) of the proximal suspension made of rubber increases substantially linearly throughout the displacement range. The rubber suspension configuration is configured to stretch, meaning that the restoring force increases linearly throughout the displacement range without tearing. As described in more detail below, this may result in a useful increase in the resonant frequency of the vibrator. Therefore, the magnet unit of the vibrator with a proximal suspension containing an elastic material may also experience an increased amount of mechanical damping at larger displacements, which is very useful for preventing the magnet unit from bottoming out. t = K1 + K2. The combined stiffness of the suspension increases with increasing displacement, providing a restoring force back to the rest position.

[0244] Figure 18B shows Figure 12 a graphical representation of the stiffness distribution of the vibrator 500 having a shallow coiled geometry. In particular, Figure 18B shows how the combined and individual stiffnesses of a rubber suspension (in this example the secondary K1 suspension) and a metal suspension (in this example the primary K2 suspension, where K2 > K1 when the vibrator is at rest) vary with displacement from the rest position (displacement = 0 mm).

[0245] As Figures 18A to 18B shown, the stiffness of each suspension in both arrangements increases with increasing displacement. However, in Figure 18AIn [the figure], the stiffness of the fabric suspension (represented by the lower line) within the displacement range is more constant than that of the rubber suspension of the current invention in Fig. 18b (represented by the lower line), and the stiffness of the latter rubber suspension shows a significant increase with displacement. Therefore, the proximal suspension made of rubber provides more stiffness at larger displacements of the magnet unit, which helps to control the movement of the magnet unit, thereby improving the durability of the vibrator.

[0246] Figure 18B It is also shown how the proximal (rubber) suspension with a curled geometry results in an asymmetric stiffness distribution with respect to the rest position (displacement = 0 mm). In the example shown, the amount by which the stiffness of the proximal (rubber) suspension increases with displacement is greater for positive displacements than for negative displacements. This is the result of the proximal (rubber) suspension being configured in a shallow curl geometry. As Figure 18B shown, when the magnet unit is at the maximum positive displacement, the stiffness K1 of the proximal (rubber) suspension is at least twice that when the magnet unit is at the rest position, and when the magnet unit is at the maximum negative displacement, the stiffness K1 is at least twice that at the rest position.

[0247] Figure 19A Shows the relationship between the maximum displacement and frequency of the magnet unit of a vibrator with a fabric proximal (K1) suspension according to GB2108925.5 (see Appendix) at different RMS excitation voltages.

[0248] Figure 19B Shows Figure 12 the relationship between the maximum displacement and frequency of the magnet unit of a vibrator constructed according to

[0249] Figures 20A to 20B i.e., a vibrator with a rubber proximal (K1) suspension with a single shallow curl geometry at different RMS excitation voltages. Figures 19A to 19B Shows the relationship between the acceleration (in dB ref. 10 -6 m / s 2 squared) and frequency of the vibrators used to generate

[0250] Figure 19A and Figure 20A at different RMS excitation voltages. In each case, the vibrator is attached to a 1 kg freely suspended test mass. The acceleration can be regarded as a measure of the vibration transfer efficiency of the vibrator to the application device. Figure 19A In [the figure], it can be seen that the prior art vibrator exhibits a relatively higher magnet unit displacement at the resonant frequency Fs compared to the vibrator with a rubber proximal (K1) suspension. This causes the vibrator to bottom out at the resonant frequency Fs. This can be seen from the

[0251] artifacts visible at high voltages in Figure 19B and Figure 20BIt is shown that the vibrator with the rubber proximal (K1) suspension exhibits smoother performance over the frequency range without bottoming out. Figure 19B and Figure 20B In addition, Figure 19B and Figure 20B It is shown that the resonant frequency Fs (indicated by the peak position) of the vibrator with the rubber proximal (K1) suspension increases with increasing excitation voltage, which is due to the power compression effect of the rubber suspension. This means that higher vibrator vibration energy can be achieved.

[0252] Figure 21 A vibrator ( Figure 21 The upper middle curve shows that Figure 12 The rubber proximal end (K1) suspension and the curling geometry of the vibrator ( Figure 21 The quality factor of the image (shown in the lower middle curve) varies with displacement.

[0253] The quality factor of a vibrator can be viewed as a representation of the amount of damping of the vibrator's moving mass, where a lower quality factor indicates a higher amount of damping. For a vibrator, a lower quality factor at higher displacements is more desirable (ie, more damping at higher displacements).

[0254] Figure 21 It is shown that the quality factor of the prior art vibrator follows a conventional "U-shape", i.e. an upright "U-shape", which is the expected shape of a conventional vibrator. In contrast, the measured quality factor of the vibrator of the present invention is an inverted "U-shape". This is believed to be due to the increased energy losses of the rubber element with increasing stretch, which increases the mechanical damping at high displacements, combined with the effect of air volume and losses, which introduces additional, but also progressive, mechanical damping.

[0255] Experimental Data II

[0256] Typical vibrators are designed to transfer vibrations to an application device within a frequency range of 20 Hz - 300 Hz. Usually, the vibrator has a relatively high moving mass, ranging between 40 g and 200 g, in order to maximize the force transmitted to the target object. Such a high moving mass results in a very high mechanical quality factor, typically in the range of 9 to 40. This means that the efficiency at the resonant frequency is very high, leading to high acceleration but also high velocity and displacement only within a small frequency band near the resonant frequency. Since vehicle vibrators are usually installed within a compact seat unit, they typically need to be very thin (usually with a thickness in the range of 12 mm to 30 mm), which means that the space available for the motor system to move within the vibrator is limited. Therefore, the present inventors have observed that it may be desirable to limit the displacement of the magnet unit at the resonant frequency by introducing damping to the magnet unit, thereby reducing the quality factor of the vibrator.

[0257] In a vibrator, the total quality factor can be expressed as

[0258] Q ts =(Q ms *Q es ) / (Q ms +Q es )

[0259] where Q ms is the mechanical quality factor, Q es is the electrical quality factor, which is mainly driven by the voice coil resistance R E and the force coefficient B l . From this, it can be understood that there are different ways to reduce the total quality factor, which can be achieved by adjusting either the electrical quality factor or the mechanical quality factor.

[0260] The electrical quality factor is known to have the following relationship with the resonant frequency, moving mass, resistance, and force coefficient:

[0261]

[0262] where ω s is the resonant angular frequency in rad / s, R E is the resistance of the voice coil, M ms is the moving mass, and B l is the force coefficient.

[0263] This shows that improving the damping in the system by adjusting the electrical quality factor means increasing the force coefficient by using larger magnets and coils, which in turn leads to significant additional costs and also poses problems in meeting the above thickness requirements.

[0264] In contrast, according to the teachings of the present invention, the mechanical quality factor of the vibrator can be reduced by introducing an elastic secondary suspension (e.g., made of rubber), thereby reducing the overall quality factor. This suspension operates through stretching. The stretching behavior is believed to contribute to generating losses that increase with the increasing speed of the magnet unit. The speed is increased by driving the motor system with a higher voltage, which means that as the driving voltage increases, the vibrator gradually becomes more damped. Additionally, as the suspension stretches, the restoring force becomes increasingly high according to Hooke's law, resulting in a gradual increase in the resonant frequency, thereby producing power compression, which helps to gradually limit the displacement of the motor system.

[0265] Also according to the teachings of the present invention, the mechanical quality factor of the vibrator can be reduced by introducing air damping, thereby reducing the overall quality factor. This is achieved by making the secondary suspension from an airtight material to form a sealed air volume together with the motor system and the plastic that houses the voice coil. When fully sealed, this air volume can act as a third spring in the system, increasing the stiffness already provided by the primary and secondary suspensions.

[0266] The stiffness of the enclosed air volume can be expressed as

[0267]

[0268] where ρ0 is the air density (Kg / m 3 ), c is the speed of sound in air, S D is the effective radiation area (in this example, including the surface area of the magnet unit and part of the suspension that is responsible for modulating the pressure in the air volume), and Volume is the volume of the housing.

[0269] A fully sealed air volume may have limited applicability within the preferred volume range (5 cm 3 to 30 cm 3 ) in this application because the increase in the resonant frequency may be too high for use as a vibrator. To reduce the resonant frequency, openings can be introduced in the voice coil housing. By covering the openings with a material having a suitable specific airflow resistance R s (preferably in the range of 0 to 5000 Pa.s / m, more preferably in the range of 50 to 2500 Pa.s / m), an additional and controlled amount of damping to the magnet unit can be introduced. This damping is also progressive and increases with the increasing driving voltage (and thus speed).

[0270] In addition to introducing damping, the system causes the effective volume in the housing to vary according to the specific airflow resistance of the material used, so that the resonant frequency of the system can vary between a free-air vibrator (which does not provide additional air volume stiffness when the specific airflow resistance of the covering material is very low or there is no covering material) and a vibrator in which the magnet unit moves in a sealed air volume (i.e., if the specific airflow resistance of the covering is very high, making the vibrator appear completely sealed).

[0271] This effect is illustrated by Figure 22 and Figure 23 which shows the relationship between the displacement and acceleration of the motor system and frequency.

[0272] The vibrator used to generate Figure 22 and Figure 23 has the following parameters: force coefficient Bl 4.8 [T*m], coil resistance Re [6.8 Ohm], moving mass [58 g], total suspension stiffness Kms 5.6 [N / mm], mechanical resistance Rms 1.6 [N.s / m], radiation area SD 12.56 [cm^2]. The vibrator has a secondary suspension made of rubber, including the air volume between the motor system and the voice coil housing, and the volume of the voice coil housing is 10 cm 3 . The vent holes are provided in the voice coil housing in the form of openings, with a surface area Sr of 2.77 cm 2 . Figure 22 and Figure 23 Each line of

[0273] Figure 22 and Figure 23 shows the results when the opening is open ("free air"), sealed ("sealed volume"), and when the vent holes are covered with materials of different specific airflow resistances (1000 Pa.s / m, 2300 Pa.s / m, 5000 Pa.s / m).

[0274] The maximum achievable resonant frequency shift depends on the volume of the enclosed air and can be derived from the following formula:

[0275]

[0276] Where α is the ratio of the acoustic compliance (the reciprocal of the above-mentioned acoustic stiffness) to the mechanical compliance of the primary and secondary suspensions. In the analyzed case, when the specific airflow resistance is 2300 Pa.s / m, the displacement is flattest in frequency, while causing a significant loss of acceleration efficiency near the free-air resonance frequency of 50 Hz.

[0277] Figure 24 and Figure 25 shows the variation of the resonance frequency Fs and the quality factor of the covering ventilation hole material with more specific airflow resistance values (500 Pa.s / m to 5000 Pa.s / m) for a vibrator with an airtight proximal (K1) suspension (as described with respect to Figure 22 and Figure 23 ). The specific airflow resistance of the covering material is shown for different housing volumes (i.e., the size of the air volume enclosed by the proximal (K1) suspension and the frame). All other vibrator parameters are kept constant, as well as the open area (S r ) of the opening in the voice coil housing. The acoustic impedance of a system consisting of an enclosed air volume with a given-sized opening and a covering material with a given specific airflow resistance can be calculated as where R a is the acoustic impedance of the system in Pa.s / m 3 , R s is the specific airflow resistance of the material in Pa.s / m, and S r is the surface area of the material through which air can pass in m 2 . The specific airflow resistance of the material can also be referred to as the surface impedance.

[0278] As described by the above equation regarding K am , the housing volume is inversely proportional to the square of the surface area of the moving mass. Figures 23 to 24 shows the results when the effective radiation area S D is 12.56 cm 2 .

[0279] Figure 24 shows that when the specific airflow resistance of the material changes from 500 Pa.s / m to 2000 Pa.s / m, the resonance frequency F s can increase by 30%. This increase in F s is roughly independent of the change in the housing volume. Starting from 2000 Pa.s / m, the housing volume begins to have a greater influence on the resonance frequency F s , where a small change in the specific airflow resistance of the covering material results in a greater increase in F s . As the acoustic impedance increases, it is believed that the air in the air volume is substantially sealed within the air volume, causing the resonance frequency to stabilize at a fixed value.

[0280] Figure 25 It is shown that the quality factor decreases roughly linearly and is independent of the housing volume until the acoustic impedance reaches 1000 Pa·s / m, after which the housing volume starts to have a higher correlation. When the acoustic impedance exceeds 2000 Pa·s / m, the quality factor starts to increase again after reaching a minimum value. This can be understood because at high acoustic impedance values, the air volume is essentially sealed. This increase is more obvious for larger housing volumes, where the resonance frequency shift is lower.

[0281] Based on Figure 24 and Figure 25 , for the tested vibrators, the preferred range of the specific airflow resistance of the covering material will be from 0 to 5000 Pa·s / m, where values of the specific airflow resistance close to 0 correspond to a substantially open volume. In these examples, the covering material is only used for dust protection. Values of the specific airflow resistance exceeding 5000 Pa·s / m will result in the resonance frequency F s being too high for most application devices (such as vehicle seat application devices), and the quality factor starts to increase again (as Figure 25 shown).

[0282] Based on Figure 23 and Figure 24 , the preferred range of the housing volume can be from 5 cm 3 to 30 cm 3 , more preferably from 10 cm 3 to 30 cm 3 , and the preferred range of the surface area of the moving mass (i.e., the magnet unit) can be from 3 cm 2 to 50 cm 2 , more preferably from 8 cm 2 to 20 cm 2 .

[0283] Experimental Data III

[0284] The following figure ( Figures 26 to 28 ) shows the experimental results of a vibrator with a shallow coil suspension similar to Figure 12 , where the proximal suspension is made of rubber, the distal suspension is made of metal, and the vibrator also includes a vent hole covered with a material having a specific flow resistance (see the parameters below). In these experiments, when the vibrator is stationary, the rubber proximal suspension has a greater stiffness K2, and the metal distal suspension has a smaller stiffness K1 (i.e., in these experiments, when the vibrator is stationary, the proximal suspension containing the elastomeric material is the stiffer suspension, and the other distal suspension is the less stiff suspension). However, as shown below, the inventors have found that the vibrator implemented in this way can also exhibit the above-mentioned advantageous technical effects, as shown by the following results.

[0285] Figure 26 Shows a graphical representation of the stiffness distribution when the vibrator is at rest. In particular, Figure 26 shows how the stiffness of each suspension (rubber proximal suspension and metal distal suspension) varies with displacement from the rest position (displacement = 0 mm).

[0286] The vibrator has the following small-signal parameters: force coefficient Bl 7 [T*m], coil resistance Re [7 Ohm], moving mass [88 g], total suspension stiffness Kms 11 [N / mm], mechanical resistance Rms 7.6 [N.s / m], radiation area SD [12.6 cm 2 . In addition, the enclosed air volume is 10 cm 3 , and the vibrator includes ventilation holes with a total area of 2.72 cm 2 , which are covered with a material having a specific airflow resistance of 430 Pa.s / m.

[0287] In this example, the vibrator is designed to mechanically handle high electrical power, so high stiffness progression and high damping are required.

[0288] As Figure 26 shown, the combined stiffness of the two suspensions increases as the displacement of each suspension increases. This is because the stiffness of the rubber suspension is shown to increase significantly with displacement. In this vibrator, the stiffness contributed by the rubber suspension is more significant than that of the metal suspension, both at the equilibrium position and as the displacement becomes larger, the dominance of the rubber suspension increases. The metal suspension has a lower stiffness than the rubber suspension at rest, showing the expected substantially linear behavior with displacement.

[0289] Figure 27 Shows Figure 26 a comparison of the variation of the quality factor (Qts) with displacement of the vibrator with prior art vibrators (i.e., vibrators having a rubber proximal suspension and a metal distal suspension, where the rubber suspension is stiffer than the metal suspension at rest) and a vibrator having a fabric proximal suspension.

[0290] This figure shows that a rubber suspension configured to be stretched provides higher initial damping compared to a fabric suspension not configured to be stretched. Since Qts is also proportional to the resonant frequency (Fs), the more progressive design in this vibrator results in the Qts curve not inverting (being "U-shaped") as in Figure 21 the previous example. Essentially, the high increase in Fs "masks" the increase in damping. Therefore, in this case the Qts curve does not invert. However, the Qts curve is flatter and lower than the Qts curve of the prior art vibrator.

[0291] Figure 28 Shows Figure 26 the relationship between the maximum displacement of the magnet unit and frequency of the vibrator at different RMS excitation voltages.

[0292] Compared with Figure 19A and Figure 20A the results of the prior art vibrators in Figure 28 it is shown that the vibrator with a rubber proximal suspension exhibits smoother performance in the frequency range without bottoming out. Therefore, Figure 28 the vibrator in

[0293] Summary statement

[0294] Features expressed in the foregoing description, the following claims or the drawings in a specific form or by means of performing the disclosed functions or by a method or process for obtaining the disclosed results may be used alone or in any combination of such features to implement the present invention in various forms.

[0295] Although the present invention has been described in connection with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art after reading this disclosure. Therefore, the above exemplary embodiments of the present invention are considered to be illustrative rather than restrictive. Various changes may be made to the embodiments without departing from the spirit and scope of the present invention.

[0296] To avoid any doubt, any theoretical explanations provided herein are for enhancing the reader's understanding. The inventors do not wish to be bound by these theoretical explanations.

[0297] Any chapter headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0298] Throughout this specification, including the appended claims, unless the context requires otherwise, the words "comprise" and "include" and their variants such as "comprises" and "includes" will be understood to imply the inclusion of the stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0299] It must be noted that, as used in this specification and the appended claims, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from that one particular value and / or to that another particular value. Similarly, when values are expressed as approximations by use of the antecedent "about", it should be understood that the particular value forms another embodiment. The meaning of "about" in a numerical relationship is optional, e.g., meaning ±10%.

[0300] References

[0301] The following publications are cited above to more fully describe and disclose the present invention and the prior art in the field to which the present invention pertains. The complete citations of these references are as follows. The entire contents of all these references are incorporated herein by reference.

[0302] · US4354067 (Yamada)

[0303] · US4675907 (Itagaki)

[0304] · US6377145B1 (Kumagai)

[0305] · US7372968B2 (Buos)

[0306] · GB2108925.5

[0307] · US2013 / 0076162A1

[0308] Appendix - Excerpt from GB2108925.5

[0309] This appendix contains an excerpt from GB2108925.5, which serves as the relevant background of the present invention.

[0310] Overview

[0311] In a first aspect, the present invention can provide: A vibrator for transmitting vibration to an application device, the vibrator having:

[0312] A frame including an attachment surface for attaching the vibrator to the application device;

[0313] A magnet unit configured to provide a magnetic field in an air gap;

[0314] A coil assembly including a voice coil mounted on a voice coil bobbin, wherein the voice coil bobbin is attached to the frame at a voice coil bobbin attachment surface on the frame, and the voice coil bobbin is configured to position the voice coil in the air gap when the vibrator is stationary;

[0315] Wherein when the vibrator is activated by supplying current to the voice coil, the magnet unit is configured to move relative to the voice coil along the movement axis of the vibrator;

[0316] Wherein the magnet unit is suspended from the frame by a suspension device including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, and the proximal suspension is closer to the voice coil bobbin attachment surface on the frame than the distal suspension when the vibrator is stationary;

[0317] Wherein one of the proximal suspension and the distal suspension has a stiffness K1, and the other of the proximal suspension and the distal suspension has a stiffness K2, where K2 > K1, and the ratio K1 / K2 is 0.4 or less.

[0318] The inventor has found that, compared with using a single suspension, using two suspensions located at different positions along the movement axis helps to reduce the rocking motion. Since there are two suspensions, it is not necessary to mount the suspension on the plane where the centroid of the magnet unit is located as in Buos (described in the background art section) to reduce the rocking motion.

[0319] In addition, by making one suspension (with stiffness K2) dominate in providing the stiffness of the suspension device compared to another less stiff suspension (with stiffness K1), the dominant suspension can provide the durability of the suspension device, while the less stiff suspension can provide the stability against rocking motion at a lower cost than using two equally stiff suspensions.

[0320] The vibrator can be regarded as stationary when no current is supplied to the voice coil.

[0321] The application device can be any object or device that can be attached to the vibrator through the attachment surface of the application device on the frame. In some examples, the application device can be a vehicle seat.

[0322] Stiffness is a known parameter of the suspension, which can be measured by applying a controlled increasing and decreasing force to the suspension element and measuring the displacement at any applied force. The techniques for measuring stiffness are known. In the context of the present invention, the stiffness can be measured relative to the displacement of the magnet unit from its stationary position (the position where the magnet unit is located when the vibrator is stationary), as Figure 5 shown, the stiffness increases as the displacement from the stationary position increases. Similarly, the resonant frequency Fs can be measured / calculated based on the magnet unit being in its stationary position.

[0323] The stiffness K1 can be 0.1 N / mm or higher, preferably 0.2 N / mm or higher, more preferably 0.4 N / mm or higher.

[0324] The stiffness K1 can be 20 N / mm or lower, preferably 10 N / mm or lower.

[0325] In some examples, K1 can be in the range of 0.4 N / mm to 10 N / mm.

[0326] The stiffness K2 can be 1 N / mm or higher, preferably 2 N / mm or higher.

[0327] The stiffness K2 can be 100 N / mm or lower, preferably 50 N / mm or lower.

[0328] In some examples, K2 can be in the range of 2 N / mm to 50 N / mm.

[0329] Fs can be 30 Hz or higher, preferably 40 Hz or higher.

[0330] Fs can be 200 Hz or lower, preferably 100 Hz or lower, more preferably 70 Hz or lower.

[0331] In some examples, Fs can be in the range of 30 Hz to 200 Hz, such as in the range of 30 Hz to 70 Hz.

[0332] Preferably, the suspension with stiffness K2 is a metal suspension, i.e., made of metal. By giving it an appropriate geometry, the metal suspension can be made to dominate the overall stiffness of the suspension device, especially when the suspension with stiffness K1 is formed of a cheap material (such as fabric (e.g., muslin)).

[0333] The metal suspension can be made of a metal plate. The thickness of the metal plate can be 1 mm or less.

[0334] The metal suspension can have one or more cuts to facilitate proper behavior. One or more cuts can have a spiral shape.

[0335] The suspension with stiffness K2 is preferably annular and is positioned to extend circumferentially around the magnet unit.

[0336] Thus, the suspension with stiffness K2 can include one or more (preferably multiple, preferably at least three) attachment tabs located on its outer periphery, where one or more attachment tabs facilitate the mechanical connection of the distal suspension to the frame. More preferably, the frame includes one or more slots, each slot corresponding to a respective attachment tab on the outer periphery of the suspension with stiffness K2, where one or more attachment tabs facilitate the mechanical connection of the distal suspension to the frame by a bayonet connection, where the attachment tab engages with the corresponding slot in the frame. This helps to accurately position the suspension with stiffness K2 when attaching it to the frame.

[0337] Preferably, the suspension with stiffness K1 is a fabric suspension, i.e., made of fabric. Preferably, the fabric suspension includes corrugations as this can help strengthen the fabric suspension.

[0338] Of course, those skilled in the art will understand that the stiffness of each suspension depends in part on the material of the suspension, the geometry of the suspension, and the connection of the suspension to the frame.

[0339] The suspension with stiffness K1 can be rotationally symmetric. It can be configured to be used in either direction. The suspension with stiffness K1 can be symmetric in other ways.

[0340] The suspension with stiffness K1 is preferably annular and is positioned to extend circumferentially around the magnet unit. If the suspension with stiffness K1 is a fabric suspension including corrugations, the corrugations preferably extend circumferentially around the magnet unit.

[0341] The present inventors have found that the use of a combination of a metal suspension (as a suspension having a stiffness K2) and a fabric suspension (as a suspension having a stiffness K1) is particularly advantageous in providing the above-mentioned beneficial effects, because such a combination can provide a vibrator that resists rocking motion and is easy to manufacture.

[0342] The ratio K1 / K2 can be 0.35 or less. The ratio K1 / K2 can be 0.3 or less, or even 0.25 or less. The lower the ratio K1 / K2, the more dominant the suspension having a stiffness K2 is in providing the stiffness of the suspension device.

[0343] The proximal suspension can have a stiffness K1, and the distal suspension can have a stiffness K2. This is particularly convenient for the manufacturing process of forming a vibrator from component parts, especially when the frame includes a main frame and a sub-frame (see below). In addition, the distal suspension is the suspension that would be exposed if there is no protection, so it is advantageous to expose the stiffer suspension (more likely to be durable, such as made of metal) rather than the less stiff suspension (possibly made of a soft fabric material and more likely to be damaged). However, it is also possible that the proximal suspension has a stiffness K2 and the distal suspension has a stiffness K1.

[0344] The magnet unit can include a U-shaped yoke, which is U-shaped when viewed in cross-section, where the U-shaped yoke has a base end corresponding to the bottom of the U-shape and an open end corresponding to the open end of the U-shape. Preferably, the U-shaped yoke is mounted in the vibrator with its base end further away from the voice coil attachment surface than the open end.

[0345] Preferably, the U-shaped yoke includes an open end attachment surface at the open end, where the inner circumference of the proximal suspension connecting the frame and the magnet unit is attached to the open end attachment surface of the magnet unit.

[0346] The U-shaped yoke can be provided with a shoulder at its open end to provide the open end attachment surface. The shoulder can be an annular groove formed at the open end of the U-shaped yoke.

[0347] Preferably, the U-shaped yoke includes a base end attachment surface at the base end, where the inner circumference of the distal suspension connecting the frame and the magnet unit is attached to the base end attachment surface of the magnet unit.

[0348] The U-shaped yoke can be provided with a shoulder at its base end to provide the base end attachment surface. The shoulder can be an annular groove formed at the base end of the U-shaped yoke.

[0349] The vibrator can be divided into a proximal side and a distal side by an intermediate plane perpendicular to the axis of motion and passing through the voice coil (when the vibrator is stationary), where the proximal side of the vibrator is the side where the intermediate plane includes the voice coil bobbin attachment surface, and the distal side is the other side of the intermediate plane.

[0350] To avoid any doubt, the intermediate plane can be located anywhere along the axis of movement, provided that it passes through the voice coil and does not lie at the end of the vibrator.

[0351] Preferably, the proximal suspension is located on the proximal side of the vibrator and the distal suspension is located on the distal side. This helps to suppress the rocking motion of the vibrator during use. The base end attachment surface of the U-shaped yoke can be located on the distal side of the vibrator and the open end attachment surface can be located on the proximal side. However, other arrangements are possible.

[0352] The application device attachment surface can be located on the proximal side or the distal side of the intermediate plane, or can even be located on the intermediate plane itself, since the application device attachment surface typically varies depending on the application device.

[0353] The frame can include a main frame and a sub-frame connected together, where the main frame includes the application device attachment surface.

[0354] The main frame can include at least one distal suspension attachment surface for connecting the distal suspension. The at least one distal suspension attachment surface can be provided by one or more slots in the main frame, each slot corresponding to a respective attachment tab on the outer periphery of the distal suspension, where the one or more attachment tabs facilitate a mechanical connection of the distal suspension to the main frame through a bayonet connection, where the attachment tabs engage with the corresponding slots in the frame when attaching the suspension to the frame. In this arrangement, the distal suspension preferably has a stiffness K2.

[0355] The sub-frame can include a voice coil bobbin attachment surface.

[0356] The main frame and / or the sub-frame can include at least one proximal suspension attachment surface for connecting the outer periphery of the proximal suspension. In some embodiments, both the main frame and the sub-frame can include at least one proximal suspension attachment surface for connecting the outer periphery of the proximal suspension, where the outer periphery of the proximal suspension is clamped between at least one proximal suspension attachment surface of the main frame and at least one proximal suspension attachment surface of the sub-frame.

[0357] The dust cover can be part of the sub-frame, for example, the dust cover can be attached to another frame element to form the sub-frame. The dust cover can be configured to prevent dust from entering the U-shaped yoke of the magnet unit.

[0358] The voice coil can include at least two layers, preferably four layers (i.e., the wire forming the voice coil can be wound around the voice coil bobbin to form at least two layers of coils), since this helps to improve the performance of the vibrator.

[0359] The air gap can extend around the axis of movement.

[0360] The frame (preferably the sub-frame) can include one or more channels for guiding the wire of the voice coil out of the vibrator.

[0361] In a second aspect, the present invention may provide an apparatus, comprising:

[0362] a vibrator according to the first aspect;

[0363] an application device, wherein the vibrator is attached to the application device through an attachment surface of the application device.

[0364] The application device may be a seat, such as a vehicle seat. In an example, the vibrator may be attached to the seat (such as a vehicle seat) through a frame of the vehicle seat, foam in the seat, or a rigid panel in the seat, wherein the rigid panel may form a soundboard of the vibrator.

[0365] The application device may be an acoustic panel configured to generate sound when the vibrator is activated by supplying current to a voice coil. As is well known in the art, an acoustic panel typically has high stiffness and is appropriately damped to generate sound when vibrating at audio frequencies.

[0366] In a third aspect, the present invention may provide a method of forming a vibrator according to the first aspect.

[0367] In a preferred example, the method may include:

[0368] attaching a voice coil bobbin to a sub-frame at a voice coil bobbin attachment surface on the sub-frame, wherein the voice coil is mounted to the voice coil bobbin;

[0369] attaching an open end of a U-shaped yoke of a magnet unit to an inner circumference of a proximal suspension, wherein the magnet unit is configured to provide a magnetic field in an air gap;

[0370] attaching an outer circumference of the proximal suspension to the sub-frame (such as at at least one proximal attachment surface of the sub-frame);

[0371] attaching a main frame to the sub-frame to form a frame (optionally while clamping the outer circumference of the proximal suspension between at least one proximal attachment surface of the main frame and at least one proximal attachment surface of the sub-frame);

[0372] attaching an outer circumference of a distal suspension to the main frame (optionally by a mechanical connection, such as the bayonet connection described above); and

[0373] attaching a base end of the U-shaped yoke of the magnet unit to an inner circumference of the distal suspension (such as by glue);

[0374] wherein one of the proximal suspension and the distal suspension has a stiffness K1, and the other of the proximal suspension and the distal suspension has a stiffness K2, where K2 > K1, and the ratio K1 / K2 is 0.4 or less.

[0375] This method provides a particularly simple way of manufacturing a vibrator that is low in manufacturing cost and resistant to rocking motion, especially when the distal suspension has a stiffness K2 and the proximal suspension has a stiffness K1, and in particular when a metal suspension is used as the distal suspension with stiffness K2 and a fabric suspension is used as the proximal suspension with stiffness K1.

[0376] The present invention includes combinations of the above aspects and preferred features, unless such combinations are clearly not permitted or are explicitly avoided.

[0377] BRIEF DESCRIPTION OF THE DRAWINGS

[0378] The following will discuss various embodiments and experiments that illustrate the principles of the present invention in conjunction with the drawings, where:

[0379] Figure 1A A cross-sectional view of the vibrator is shown;

[0380] Figure 1B A perspective cross-sectional view of the vibrator is shown;

[0381] Figure 1C A perspective view of the vibrator is shown;

[0382] Figure 1D An exploded view of the vibrator is shown;

[0383] Figure 1E A bottom view of the vibrator is shown;

[0384] Figure 1F A top view of the vibrator is shown;

[0385] Figure 2 A simplified model of the vibrator is shown;

[0386] Figure 3 Results indicating the resonant frequency shift of the vibrator during use are shown;

[0387] Figure 4 A numerical table indicating the resonant frequency shift of the vibrator during use is shown;

[0388] Figure 5 A graph showing how the stiffness of the suspension element varies with displacement is shown;

[0389] Figure 6 A voice coil assembly is shown;

[0390] Figure 7 A sub-frame is shown;

[0391] Figure 8A A top view of the magnet unit is shown;

[0392] Figure 8B A bottom view of the magnet unit is shown;

[0393] Figure 8C Shows a cross-sectional view of the magnet unit;

[0394] Figure 9 Shows the fabric suspension;

[0395] Figure 10A Shows a series of exemplary metal suspensions;

[0396] Figure 10B Shows an exemplary metal suspension.

[0397] Detailed description

[0398] The various aspects and embodiments of the present invention will be discussed below in conjunction with the accompanying drawings. For those skilled in the art, other aspects and embodiments will be apparent. All documents mentioned herein are incorporated herein by reference.

[0399] Figures 1A to 1F Shows an example of the vibrator 100.

[0400] Figures 1A to 1F Shows a cross-sectional view, a perspective cross-sectional view, a perspective view, an exploded view, a bottom view, and a top view of the vibrator 100 respectively (the directions of the vibrator 100 in the bottom and top views are for reference, note that the direction of the vibrator 100 may be different in actual installation). Figures 1A to 1B in the direction of the vibrator 100, note that the direction of the vibrator 100 may be different in actual installation).

[0401] As Figure 1A , Figure 1B and Figure 1D shown, the vibrator 100 includes a frame 110 composed of a main frame 112 and a sub-frame 114.

[0402] In this example, the sub-frame 114 is composed of a frame element 115 and a dust cover 116, and the dust cover 116 is attached to the frame element 115. In other examples, the frame element 115 and the dust cover may be integrally formed, or the dust cover 116 may be omitted.

[0403] The coil assembly 120 includes a voice coil 122 mounted on a voice coil bobbin 124, and the coil assembly 120 is attached to the sub-frame 114 at the voice coil bobbin attachment surface on the sub-frame 114. In this example, the voice coil bobbin 124 is sandwiched between the frame element 115 and the dust cover 116, so the voice coil bobbin attachment surface 115a (the position where the voice coil bobbin 124 is attached to the sub-frame 114) can be provided by the frame element 115 and / or the dust cover 116.

[0404] The voice coil bobbin 124 is configured to position the voice coil 122 within the air gap 132 provided by the magnet unit 130 (see below). The main frame 112 and / or the sub-frame 114 may include an application device attachment surface for attaching the vibrator 100 to an application device.

[0405] In this particular example, the application device is the seat frame of a vehicle seat, and the application device attachment surface 112a is an annular surface provided by an annular protrusion on the main frame 112. Multiple application device attachment surfaces may be provided.

[0406] The magnet unit 130 of the vibrator 100 includes a U-shaped yoke 134, a magnet 136, and a spacer 138. The shape of the magnet unit 130 provides an annular air gap 132, and the magnet unit 130 provides a magnetic field in the air gap.

[0407] In use, applying a current to the voice coil 122 generates a magnetic field in the voice coil, which interacts with the magnetic field provided by the magnet unit 130 in the air gap, causing the magnet unit 130 to move relative to the voice coil 122 along the movement axis 102 of the vibrator 100. Of course, the movement of the magnet unit 130 relative to the voice coil 122 along the movement axis 102 can also be regarded as the movement of the voice coil 122 relative to the magnet unit 130.

[0408] The magnet unit 130 is suspended from the frame 110 by a suspension device that includes a proximal suspension 140 (connecting the main frame 112 and the magnet unit 130) and a distal suspension 142 (connecting the main frame 112 and the magnet unit 130). The proximal suspension 140 is closer to the voice coil bobbin attachment surface 115a than the distal suspension 142.

[0409] In this example, the proximal suspension 140 and the distal suspension are attached to the U-shaped yoke 134 of the magnet unit 130. The U-shaped yoke 134 is U-shaped in cross-section and includes a proximal attachment surface (for the proximal suspension 140) at the open end of the U-shape and a distal attachment surface (for the distal suspension 142) at the bottom of the U-shape.

[0410] As Figure 1B shown, the U-shaped yoke 134 has a shoulder at its open end to provide an attachment surface for the proximal suspension 140. This helps with bonding.

[0411] As Figure 1B shown, the U-shaped yoke 134 has a shoulder at its base end to provide an attachment surface for the distal suspension 142. This helps with bonding.

[0412] In this example, the proximal suspension 140 is attached to the frame 110 by being clamped between the main frame 112 and the sub-frame 114 and bonded with glue.

[0413] In this example, the distal suspension 142 is attached to the main frame 112 by a bayonet connection, and the attachment tab 144 of the distal suspension 142 engages with the slot 113 of the main frame 112. The attachment tab 144 of the distal suspension 142 is glued to the slot 113 of the main frame 122 when fully inserted into the slot to ensure the connection and add some damping effect.

[0414] The vibrator 100 can be manufactured by the following method:

[0415] Attach the voice coil bobbin 124 to the voice coil bobbin attachment surface on the sub-frame 114 (for example, by gluing the voice coil bobbin 124 to the frame element 115 and the dust cover 116), where the voice coil 122 is mounted on the voice coil bobbin 124;

[0416] Attach the open end (open end attachment surface) of the U-shaped yoke 134 of the magnet unit 130 to the inner circumference of the proximal suspension 140;

[0417] Attach the outer circumference of the proximal suspension 140 to the sub-frame 114 (of the frame element 115);

[0418] Attach the main frame 112 to the sub-frame 114 (of the frame element 115) to form the frame 110, while clamping the outer circumference of the proximal suspension 140 between the main frame 112 and the sub-frame 114 (of the frame element 115);

[0419] Attach the outer circumference of the distal suspension 142 to the main frame 112 (by the above-mentioned bayonet connection); and

[0420] Attach the base end (base end attachment surface) of the U-shaped yoke 134 of the magnet unit 130 to the inner circumference of the distal suspension 142.

[0421] Since the distal suspension 142 is installed by a bayonet connection, the distal suspension 142 can accurately position other components relative to the movement axis 102 of the vibrator 100. In fact, other components can be aligned by positioning the magnet unit 130 and the proximal suspension 140 within the vibrator 100.

[0422] The proximal suspension 140 and the distal suspension 142 are configured to have different stiffnesses. In this example, the distal suspension 142 has a stiffness K2, and the proximal suspension 140 has a stiffness K1, where K1 < K2. The ratio K1 / K2 can be 0.4 or less. Therefore, in this example, the main stiffness of the suspension device is provided by the distal suspension 142. This can be achieved, for example, by forming the proximal suspension 140 from fabric and the distal suspension 142 from metal.

[0423] For example, K2 can range from 3 N / mm (for example, K1 = 1 N / mm, total stiffness (K1 + K2) = 4 N / mm, K1 / K2 = 0.25, resonance frequency Fs = 35 Hz when the moving mass is 86 g) to 28 N / mm (for example, K1 = 10 N / mm, total stiffness (K1 + K2) = 38 N / mm, K1 / K2 = 0.35, Fs = 100 Hz, moving mass 86 g), calculated with a K1 / K2 ratio of 0.2.

[0424] Figure 2 Shows a simplified model of the vibrator 200, which can be used to understand the seat vibrator of FIG. 1. Similar features are denoted by similar reference numerals in this specification.

[0425] Figure 2 The vibrator 200 includes a moving mass 230. The mass of the moving mass 230 is M m . The moving mass 230 is suspended from the frame 210 by a proximal suspension 240 and a distal suspension 242 and is mounted around the voice coil assembly 220. The proximal suspension 240 has a stiffness K1 and the distal suspension 242 has a stiffness K2. The total stiffness of the suspension is K t = K1 + K2, and the resonant frequency Fs of the system can be calculated as (where F s is in Hz, K t is in N / m, and the mass is in kg). The stiffness of the proximal suspension 240 and the distal suspension 242 may vary over time or with use, and thus affect the resonant frequency Fs of the system. Some materials are more prone to such changes than others. For example, the stiffness of a suspension formed of fabric may change more over time than that of a suspension formed of metal.

[0426] Figure 3 Shows the results of an experiment to illustrate such changes. The change in the resonant frequency Fs before and after an accelerated aging test was measured for a case where both the proximal suspension 240 and the distal suspension 242 were formed of fabric for the mass. In this case, the resonant frequency Fs decreased from approximately 67 Hz to approximately 40 Hz, a decrease of more than 40%.

[0427] Using materials with stiffness that does not change easily can reduce or mitigate such shift. For example, the proximal suspension 240 and the distal suspension 242 can be formed of materials such as metal. Metal is a more durable material for forming the suspension. However, a suspension formed of materials such as metal results in a significant cost increase for the device. Thus, while a vibrator including a metal proximal suspension 240 and a metal proximal suspension 242 may provide higher durability, this is offset by the increased material cost and increased manufacturing complexity.

[0428] The present inventors have realized that since Fs depends on the total stiffness of the suspension (i.e., the sum K of the stiffnesses of the components t=(K1 + K2), providing an arrangement of a primary suspension formed from a more durable material (i.e., a suspension providing more than half of the total stiffness) and a secondary suspension formed from a less durable material (i.e., a suspension providing less than half of the total stiffness) can provide an improvement in durability while reducing manufacturing complexity or an increase in material cost, while still achieving an improved stability against swaying motion achieved by using two suspensions. It is believed that the improved durability is at least partly due to the primary suspension helping to protect the secondary suspension from aging, and also because the suspension helps to limit the effects of any aging in the secondary suspension (since changes in the stiffness of the secondary suspension account for a smaller proportion of the total stiffness, and thus the overall change is reduced).

[0429] For example, the stiffness K1 of the secondary suspension can provide less than 29% of the total stiffness K t (K1 / K2 is 0.4 or less), less than 26% (K1 / K2 is 0.35 or less), less than 23% (K1 / K2 is 0.3 or less), or less than 20% (K1 / K2 is 0.25 or less). The lower the ratio K1 / K2, the more dominant the suspension with stiffness K2 is in providing the stiffness of the suspension device, and thus the smaller the effect of any change in stiffness K1 on the total stiffness K t is.

[0430] Figure 4 The results of a comparative experiment are shown. The numerical table indicates the resonant frequencies measured at certain intervals in an accelerated aging test that is the same as the one used to generate the Figure 3 results (note: the steps shown in different rows are part of a single test). Such tests are known in the art, although the details of the tests used may vary from manufacturer to manufacturer.

[0431] In the primary metal / fabric setup, the metal suspension stiffness K2 contributes 82% of the total suspension stiffness, while the fabric suspension stiffness K1 contributes 18% (K1 / K2 = 0.22). Clearly, this arrangement significantly improves the durability of the unit. In particular, the shift in the resonant frequency is reduced from 40% at the completion of the aging test to 11% (see Figure 4 the last row), showing the technical improvement provided by the suspension arrangement.

[0432] Figure 5 A graphical representation of the stiffness distribution of the vibrator 100 shown in FIG. 1 is shown. In particular, Figure 5 it shows how the stiffness of the fabric suspension 140 and the metal suspension 142 varies with the displacement from their respective rest positions. In each case, the stiffness of the suspension increases as the displacement increases, providing a strong restoring force back to the rest position. As shown, for each suspension, the stiffness increases continuously and gradually as the displacement increases, since the displacement is not sufficient to damage the suspension. The combined stiffness of the two suspension elements conforms to the relationship K t=K1+K2, thus verifying this understanding of the contribution of the first and second suspension elements to the overall stiffness of the suspension.

[0433] In the context of the present invention, the stiffness and the resonant frequency Fs may be relative to the magnet unit in its rest position ( Figure 5 The displacement on the surface is measured by (displacement = 0 mm).

[0434] The following description and related Figure 6 10 provides further specific details of the implementation of the seat vibrator 300, which is substantially the same in design as the seat vibrator 100, to aid in understanding the present invention.

[0435] Figure 6 A voice coil assembly 320 is shown, including a voice coil 322 and a voice coil former 324. The voice coil 322 forms a 4-layer thick coil on the voice coil former, terminating in two lead wires 326. Other configurations of the voice coil 322 can also be used, such as different numbers of layers, although at least three layers, preferably four layers, are believed to help optimize performance. The height of the voice coil 322 on the voice coil former (dimension 3201), the height of the lead wire 326 exit point (dimension 3202), and the spacing between the lead wires 326 (dimension 3203) can be varied according to the vibrator installation needs.

[0436] Figure 7 The frame member 315 of the subframe with the voice coil assembly 320 attached is shown. The frame member 315 includes a channel 317 that guides the lead wires 326 of the voice coil assembly 320 through holes 317a to the attachment tabs 328 (although the attachment tabs 328 are Figure 7 315, but the lead wires 326 are attached to an attachment piece 328 that is not visible on the other side of the frame element 315). The attachment piece 328 can be used to attach the voice coil assembly 320 to a power source, such as by soldering the power source to the attachment piece 328. The use of the channel 317 can reduce the requirement for tight manufacturing tolerances of the voice coil assembly 320, such as by making the channel 317 wide enough. The use of the channel 317 also helps guide the lead wires to the outlet hole 317a to land correctly on the attachment piece 328.

[0437] Figure 8A , Figure 8B and Figure 8C A top view, a bottom view, and a cross-sectional view of a magnet unit 330 for a vibrator are shown. Figure 8A The magnet unit 330 is viewed from the base end of the U-shaped yoke 334. Figure 8B When observing the magnet unit 330 from the open end of the U-shaped yoke 334 , the spacer 338 and the air gap 332 can be seen. Figure 8C A cross-sectional view of the magnet unit 330 attached to the frame 312 via the proximal suspension 340 is shown. Figure 8CThe vibrator in [reference] is inverted compared to, for example, the illustration of Figure 1 (i.e., the surface (not shown) to which the voice coil bobbin is attached would be at the top rather than the bottom of the image). In the magnet unit 330, the U-shaped yoke 334 provides most of the moving mass M of the magnet unit 330 m , and the mass of the U-shaped yoke 334 can be varied by changing, for example, the wall thickness of the U-shaped yoke 334. The magnet unit 330 also includes shims 338, magnets 336( Figure 8A and Figure 8B not visible in [reference]), and provides a magnetic field in the air gap 332.

[0438] At the base end of the U-shaped yoke 334, a shoulder provides an attachment surface 3341 for the distal suspension 342 to attach the distal suspension 342 to the base end of the U-shaped yoke 334 by glue.

[0439] At the open end of the U-shaped yoke 334, another shoulder provides an attachment surface 3342 for the proximal suspension 340 to attach the proximal suspension 340 to the open end of the U-shaped yoke 334.

[0440] The shoulders in the U-shaped yoke help facilitate the connection of the suspensions 340, 342 to the U-shaped yoke, for example, by helping to prevent or reduce glue from entering, for example, the air gap 332. The width of the shoulders can be varied to ensure optimal bonding of the proximal and distal suspensions. For example, if the width of surface 3341 or surface 3342 is too small, the connection will be very difficult.

[0441] Figure 9 A partial fabric suspension 340 is shown, which can be used as a proximal suspension in a vibrator. The suspension includes a corrugated portion having corrugations 3402. The corrugations 3402 increase the stiffness of the fabric suspension 340. The fabric suspension 340 is designed and configured to allow the fabric suspension 340 to be mounted in either direction in the vibrator, with the bonding surfaces 3404a and 3404b in the same plane, and having the same stiffness behavior regardless of the mounting direction of the fabric suspension 340. This helps simplify the manufacture of the vibrator.

[0442] Thus, the bonding surfaces 3404a, 3404b to which the fabric suspension is attached to the frame and the magnet unit of the vibrator are at the same level within the fabric suspension 340. In other words, the height dimension 3408 is the same for the upper and lower surfaces as well as the inner and outer surfaces of the fabric suspension 340. Additionally, the fabric suspension 340 is configured to have symmetric stiffness, so its performance is not affected by the direction in the vibrator. Thus, the corrugations 3402 are equally spaced and the dimension 3406 is the same for each corrugation 3402. The length of the corrugations 3402 and the fabric suspension 340 can be set such that they are not fully stretched during normal operation to prevent non-linear changes in stiffness and the resulting less predictable operation, and to prevent excessive stress on the fabric suspension 340, which could damage the fabric suspension 340 over time.

[0443] Figure 10A and Figure 10B shows different configurations of the metal suspensions 342a, 342b, 342c, which can be used as distal suspensions in a vibrator. The metal suspensions 342a, 342b, 342c can be made of steel, such as tempered stainless steel, like AISI 301. The metal suspension 342 has a flat (i.e., sheet-like) configuration and can include cutouts 346, although other configurations can also be used depending on the material employed. The flat-shaped metal suspensions 342a, 342b, 342c can facilitate attachment (e.g., gluing) to the magnet unit of the vibrator. The cutouts 346 can be configured to control the mechanical properties (e.g., strength, stiffness, fatigue resistance) of the metal suspensions 342a, 342b, 342c. The metal suspensions 342b, 342c include attachment tabs 344 for attachment to the frame of the vibrator, for example, by means of the bayonet fitting described above.

[0444] The metal suspensions 342a, 342b, 342c can be formed by cutting a metal sheet (e.g., stainless steel). A suitable thickness of the metal sheet can be, for example, 0.5 mm. This can provide a resonance frequency F of approximately 50 Hz for a moving mass M of about 60 g m to provide a resonance frequency F of approximately 50 Hz s . For ease of operation, preferably, the metal suspensions 342a, 342b, 342c have no burrs or sharp edges to avoid local stress on the components, friction on other components of the vibrator, and / or injury to the person operating the components.

[0445] The metal suspensions 342a, 342b, 342c can be configured to provide a specific stiffness K2, thereby generating the desired resonance frequency Fs of the vibrator. For example, the design parameters include the thickness and type of the metal sheet, the length and width of the cutouts 346, the number of cutouts 346, and the radius of the cutouts 346. The metal regions between the cutouts can be referred to as arms 348. Longer and thinner arms tend to provide a lower overall stiffness K2, and the same is true for an increase in the radius at one end of the arm 348. The lower stiffness of the suspensions 342a, 342b, 342c in terms of material and design can result in lower stress on the arms 348 of the metal suspensions 342a, 342b, 342c, thereby improving fatigue resistance. When the metal suspension 342 vibrates, fatigue occurs and may cause cracks or failures in the metal suspensions 342a, 342b, 342c.

Claims

1. A vibrator for delivering vibration to an application device, the vibrator comprising: A frame including an application device attachment surface for attaching the vibrator to the application device; A magnet unit configured to provide a magnetic field in an air gap; A coil assembly including a voice coil mounted to a voice coil bobbin, wherein the voice coil bobbin is attached to the frame at the voice coil bobbin attachment surface on the frame, and wherein when the magnet unit is in a stationary position and the vibrator is stationary, the voice coil bobbin is configured to position the voice coil in the air gap; Wherein when the vibrator is activated by applying a current to the voice coil, the magnet unit is configured to move relative to the voice coil along the movement axis of the vibrator; Wherein the magnet unit is suspended from the frame by a suspension device, the suspension device including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, and wherein when the vibrator is stationary, the proximal suspension is closer to the voice coil bobbin attachment surface on the frame than the distal suspension; Wherein one of the proximal suspension and the distal suspension includes an elastomeric material configured to elastically stretch such that the stiffness of the suspension including the elastomeric material increases as the magnet unit moves away from the stationary position along the movement axis.

2. The vibrator according to claim 1, wherein, The suspension including the elastomeric material is configured such that: The stiffness of the suspension including the elastomeric material when the magnet unit is at the maximum positive displacement is at least twice the stiffness of the suspension including the elastomeric material when the magnet unit is in the stationary position; and The stiffness of the suspension including the elastomeric material when the magnet unit is at the maximum negative displacement is at least twice the stiffness of the suspension including the elastomeric material when the magnet unit is in the stationary position.

3. The vibrator according to any one of the preceding claims, wherein, The suspension including the elastomeric material is a flat disk extending circumferentially around the magnet unit.

4. The vibrator according to any one of claims 1 to 2, wherein, The suspension including the elastomeric material is a coiled suspension.

5. The vibrator according to claim 4, wherein, The suspension including the elastomeric material has a single coil geometry, wherein when the vibrator is stationary, the maximum extension of the coiled suspension measured along the movement axis does not exceed 40% of the width of the unclamped portion of the coiled suspension measured in a direction perpendicular to the movement axis in a plane containing the movement axis on the same side of the movement axis.

6. The vibrator according to any one of the preceding claims, wherein, The suspension including the elastomeric material is attached to the magnet unit by an attachment ring.

7. The vibrator according to claim 6, wherein, The attachment ring is formed of plastic.

8. The vibrator according to any one of the preceding claims, wherein, The other of the proximal suspension and the distal suspension is a metal suspension.

9. The vibrator according to any one of the preceding claims, wherein, The suspension including the elastomeric material is the proximal suspension, and the other of the proximal suspension and the distal suspension is the distal suspension.

10. The vibrator according to any one of the preceding claims, wherein, The vibrator has a resonant frequency Fs in the range of 30 Hz to 200 Hz.

11. The vibrator according to any one of the preceding claims, wherein, One of the proximal suspension and the distal suspension has a stiffness K1, and the other of the proximal suspension and the distal suspension has a stiffness K2, where K2 > K1 when the vibrator is stationary, and the ratio K1 / K2 is 0.4 or less.

12. The vibrator according to claim 11, wherein, The suspension including the elastomeric material has a stiffness K1, and the other of the proximal suspension and the distal suspension has a stiffness K2.

13. The vibrator according to any one of the preceding claims, wherein, The suspension including the elastomeric material is formed of an airtight material, and the suspension having the elastomeric material and the frame are configured together to enclose an air volume for resisting movement of the magnet unit along the movement axis when the vibrator is activated.

14. The vibrator according to claim 13, wherein, The frame and / or the magnet unit includes one or more ventilation holes for allowing air to be discharged from or enter the air volume.

15. The vibrator according to claim 14, wherein, Each of the ventilation holes is covered with a material having a specific airflow resistance in the range of 0 to 5000 Pa·s / m.

16. A vibrator for transmitting vibration to an application device, the vibrator comprising: A frame including an application device attachment surface for attaching the vibrator to the application device; A magnet unit configured to provide a magnetic field in an air gap; A coil assembly including a voice coil mounted to a voice coil bobbin, where the voice coil bobbin is attached to the frame at the voice coil bobbin attachment surface on the frame, and where the voice coil bobbin is configured to position the voice coil in the air gap when the vibrator is stationary; Wherein when the vibrator is activated by applying a current to the voice coil, the magnet unit is configured to move relative to the voice coil along the movement axis of the vibrator; Wherein the magnet unit is suspended from the frame by a suspension device including a proximal suspension connecting the frame and the magnet unit and a distal suspension connecting the frame and the magnet unit, where the proximal suspension is closer to the voice coil bobbin attachment surface on the frame than the distal suspension when the vibrator is stationary; Wherein one of the proximal suspension and the distal suspension is an airtight suspension, and the airtight suspension and the frame are configured together to enclose an air volume for resisting movement of the magnet unit along the movement axis when the vibrator is activated.

17. The vibrator according to any one of claims 13 to 16, wherein, The frame and / or the magnet unit includes one or more ventilation holes for allowing air to be discharged from or enter the air volume.

18. The vibrator according to claim 17, wherein, Each of the ventilation holes is covered with a material having a specific airflow resistance in the range of 0 to 5000 Pa·s / m.

19. The vibrator according to claim 18, wherein, The material covering the ventilation holes has a specific airflow resistance in the range of 50 Pa·s / m to 2500 Pa·s / m.

20. The vibrator according to any one of claims 13 to 19, wherein The volume range of the air volume is 5 cm 3 to 30 cm 3 .

21. The vibrator according to any one of claims 13 to 20, wherein, The surface area of the part of the magnet unit that moves within the air volume ranges from 3 cm 2 to 50 cm 2 .

22. The vibrator according to any one of claims 13 to 21, wherein, One of the proximal suspension and the distal suspension includes an elastomeric material configured to elastically stretch such that the stiffness of the suspension including the elastomeric material increases as the magnet unit moves away from the stationary position along the movement axis.

23. The vibrator according to any one of claims 13 to 22, wherein, The airtight suspension includes an elastomeric material configured to elastically stretch such that the stiffness of the suspension including the elastomeric material increases as the magnet unit moves away from the stationary position along the movement axis.

24. The vibrator according to any one of claims 13 to 23, wherein, The other of the proximal suspension and the distal suspension is a metal suspension.

25. The vibrator according to any one of claims 13 to 24, wherein, One of the proximal suspension and the distal suspension has a stiffness K1, and the other of the proximal suspension and the distal suspension has a stiffness K2, where K2 > K1 when the vibrator is stationary, and the ratio K1 / K2 is 0.4 or less when the vibrator is stationary.

26. The vibrator according to any one of claims 13 to 24, wherein The airtight suspension has a stiffness K1 when the vibrator is stationary.

27. An apparatus, comprising: A vibrator according to any one of claims 1 to 26; An application device, wherein the vibrator is attached to the application device through an attachment surface of the application device.

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