Linear actuator and adjustable device including such linear actuator

Abstract

A linear actuator, comprising: an upper housing; a mandrel, on the outer surface of which an external thread is formed; a motor, a transmission mechanism including a worm meshing with a worm gear on the mandrel; a mandrel nut, the internal thread of which meshes with the external thread; an inner pipe member arranged in parallel with the mandrel at a certain interval; an outer pipe member arranged in parallel with the inner pipe member at a certain interval, the mandrel nut cooperating with a linear guiding track on the outer pipe member; a rear mounting member, which is an integral member and includes a bearing receiving portion, on the inner circumference of which a circumferential groove is formed and a strip-shaped opening is formed on one side thereof, a braking member holding portion having a circumferential groove is engaged in the strip-shaped opening; a bearing arranged in the bearing receiving portion; a first stopper arranged in the groove; the front end of the mandrel is supported in the inner pipe member. Also relates to an adjustable device including the linear actuator. The rear mounting member in the present disclosure is made into a single component, ensuring the cylindricity and concentricity of the bearing receiving portion.

Description

Technical Field

[0001] The present invention relates to a linear actuator and an adjustable device including such a linear actuator. The linear actuator of the present invention is particularly suitable for use with furniture-type products for adjusting the height, length, width, and / or inclination of furniture-type products. Background Art

[0002] Linear actuators have been widely used in industry and daily life. For example, they can be applied to the adjustment of the length, width, height, and / or inclination of beds used by patients, especially those who are bedridden due to long-term illness or who are undergoing surgery or have undergone surgery. Of course, the application scope of linear actuators is not limited to this, and they can also be applied to other furniture-type products that require height, length, width, and / or inclination adjustment.

[0003] In the case where a linear actuator is applied to the above types of beds or patient lifting devices, once the linear actuator fails (for example, due to the deviation of the cylindricity or concentricity of the accommodation chamber of the rear mounting member that houses the bearing, resulting in the deviation or jamming of the spindle movement), it will pose a great danger to the patients on the above beds or devices.

[0004] Common types of actuators mainly include: an outer pipe fitting of the linear actuator; a spindle provided with an external thread thereon; a reversible motor; a transmission mechanism connected to the reversible motor; a spindle nut formed with an internal thread that meshes with the external thread on the spindle, and a sliding portion formed on the outer circumference of the maximum diameter portion of the spindle nut that cooperates with a guiding track on the inner surface of the outer pipe fitting of the actuator; an actuating element, one end of which is connected to one end of the spindle nut; a front mounting member, the other end of the actuating element is connected to the front mounting member; a rear mounting member; the rear end of the spindle is installed in the rear mounting member through a bearing; a worm gear is arranged on the spindle, and the transmission mechanism includes a worm, the worm gear meshes with the worm, and the power of the reversible motor is transmitted to the spindle through the transmission mechanism and the meshing worm gear and worm, thereby driving the spindle to rotate. The rotational drive of the spindle is converted into the forward and backward linear movement of the spindle nut through the thread fit between the spindle and the spindle nut, thereby causing the actuating element to move forward and backward, and thus pushing or pulling the front mounting member to move relative to the rear mounting member forward and backward.

[0005] However, existing linear actuators have various defects. For example, a linear drive is disclosed in CN1281882C, in which the main shaft is installed in a rear support (i.e., a rear mounting member) through a ball bearing at its rear end. It is clearly known from this prior art that the rear support is a split two-piece type, and recessed portions are formed in each half of the rear support.

[0006] In the assembled state, the two halves of the rear support are joined together relatively to form a complete receiving cavity, thereby receiving the ball bearing in the receiving cavity formed by the corresponding two recessed portions.

[0007] Obviously, such a structure has the following defects:

[0008] 1) These two halves are independently processed and manufactured in different processing procedures, and their processing precisions and processing errors are different. As a result, there are deviations in cylindricity and concentricity between the two parts of the receiving cavity of the cylinder formed by these two halves. When the bearing is installed in the receiving cavity, due to the deviations in cylindricity and concentricity of the two halves, the support loads and wear conditions received by the bearing are different, thereby causing the bearing to operate and wear inconsistently. And there is a situation where the bearing operates abnormally in the form of running off track in the receiving cavity. After a period of working time, due to the uneven wear of the bearing, the bearing will be deformed, which will cause jamming and failure of the bearing in the receiving cavity. As a result, the linear actuator and the equipment using such a linear actuator cannot work properly, which will bring great danger to the patients on the above-mentioned bed or device.

[0009] 2) When the linear actuator of the prior art is assembled, these two halves are fixed together by bolts, welding, bonding or other means. After a long time of work, due to the action of the working load, the connection bolts will become loose or the joint between the two halves will separate, which will generate the risk of misaligning or disengaging the bearing of the mandrel from its normal position. As a result, the linear actuator or the entire equipment cannot work properly. Thus, the working risk and the cost of component replacement are increased.

[0010] Based on this, in industrial applications and daily life, there is a need for an integral single component to form a single integral receiving cavity, so as to improve the cylindricity and concentricity of the receiving cavity, reduce the waste of processing materials, save labor costs, and extend the service life of the linear actuator. Summary of the Invention

[0011] The purpose of the present application is to provide a linear actuator that eliminates the defects and deficiencies in the above-mentioned prior art, which can provide a rear mounting member with the required cylindricity and concentricity, and enable the linear actuator and the adjustable equipment equipped with the linear actuator to operate smoothly and safely.

[0012] The present application relates to a linear actuator, which includes:

[0013] An upper housing;

[0014] A mandrel disposed between a front mounting member and a rear mounting member, on which a worm gear is fixedly mounted, and external threads are formed on a partial outer surface of the mandrel;

[0015] An electric motor and a transmission mechanism, the transmission mechanism includes a worm that meshes with the worm gear, the electric motor is disposed in a motor holder, and the motor holder is connected to the upper housing;

[0016] A mandrel nut disposed on the mandrel, and internal threads of the mandrel nut mesh with the external threads of the mandrel;

[0017] An inner pipe fitting, one end of the inner pipe fitting is attached to the mandrel nut, and the other end is attached to the front mounting member, and the inner pipe fitting is disposed parallel to the mandrel at a certain distance around the mandrel;

[0018] An outer pipe fitting disposed around the inner pipe fitting and parallel to the inner pipe fitting at a certain distance;

[0019] Wherein, the rear mounting member is an integral part made of a plastic material with a certain hardness, the rear mounting member includes a bearing receiving portion extending along the longitudinal axis of the mandrel, circumferential grooves are formed on the inner circumference of the bearing receiving portion and a long strip opening is formed on one side thereof, a brake member holding portion is clamped in the long strip opening, a groove is formed on the inner side of the brake member holding portion, and the groove on the brake member holding portion and the circumferential groove on the bearing receiving portion form an annular groove;

[0020] A bearing disposed in the bearing receiving portion;

[0021] A first stopper disposed in the annular groove formed by the circumferential groove on the bearing receiving portion and the groove on the brake member holding portion.

[0022] Preferably, an auxiliary bearing is provided on a base portion of the worm gear fixedly mounted on the mandrel, and the auxiliary bearing is pressed between the base portion of the worm gear and the upper housing of the linear actuator.

[0023] Preferably, a cavity is formed between the rear portion of the mandrel nut and the mandrel, and a safety nut that is threadedly engaged with the mandrel is disposed in the cavity, and the safety nut is held on the mandrel by the rear portion of the mandrel nut.

[0024] Preferably, a coupling member is fixedly mounted on the rear end portion of the mandrel, the coupling member has a stepped structure, the bearing is mounted on a small diameter portion of the stepped structure, and a winding spring is mounted on a large diameter portion of the stepped structure.

[0025] Preferably, one end of the winding spring that extends outwards is fixed by a clamping portion formed by the brake member holding portion and one side of the long strip-shaped opening, and the other end of the winding spring is fixed to the coupling member.

[0026] Preferably, the clamping portion is formed by a clamping groove on the brake member holding portion and a corresponding clamping groove on the one side of the long strip-shaped opening.

[0027] Preferably, the spindle nut is matched with a linear guiding track on the outer pipe fitting.

[0028] Preferably, the front end of the spindle is supported in the inner pipe fitting by a second stopper.

[0029] Preferably, the rear mounting member includes a mounting portion connected to the bearing accommodating portion and extending along the longitudinal axis of the spindle, and the mounting portion includes two fork legs symmetrically arranged with respect to the longitudinal axis of the spindle.

[0030] This application also relates to an adjustable device, wherein the adjustable device includes the linear actuator according to the foregoing technical content, and the front mounting member and the rear mounting member of the linear actuator are respectively mounted on corresponding mounting portions of the adjustable device to adjust the size or inclination of the adjustable device.

[0031] Preferably, the adjustable device is a rehabilitation bed or an operating bed or a furniture-type device.

[0032] Compared with the prior art, the technical solution according to the present invention can produce remarkable technical effects. For example: Since the rear mounting member in this application is processed from a single workpiece, the coaxiality and cylindricity of the bearing accommodating chamber formed in the rear mounting member are ensured; Since the rear mounting member in this application is processed from a single workpiece, the rigidity of the rear mounting member is increased, and the problem of separation between the combined components existing in the case of being formed by multiple components is avoided, thus eliminating the problems of bearing deviation, uneven wear of the corresponding parts of the bearing and the accommodating chamber, and frequent replacement of components. Further, such a structure in this application significantly reduces the material cost and processing cost.

[0033] In addition, the brake member holding portion and the corresponding long strip-shaped opening in this application play multiple roles: 1) When installing the bearing and the first stopper, the expansion of the long strip-shaped opening is beneficial to the installation of the bearing and the first stopper; 2) The adaptation of the brake member holding portion and the long strip-shaped opening realizes the fixation of the end portion of the winding spring.

[0034] Certain technical aspects of the linear actuator of the present application and the adjustable device incorporating the linear actuator have been outlined above so that the following detailed description can be better understood. Of course, there are additional embodiments to be described below, which will form the subject matter of the claims. In this regard, it should be understood that the linear actuator is not limited, in its application, to the details of the construction and the arrangement of components set forth in the following disclosure or shown in the drawings. Further, it should be understood that the language and terminology used herein are for the purpose of description and should not be regarded as limiting. Thus, the concepts upon which this disclosure is based can readily be utilized as a basis for other structures and systems designed to achieve several purposes of the linear actuator. Accordingly, it should be understood that the claims include such equivalent structures insofar as they do not depart from the spirit and scope of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Specific embodiments of the linear actuator of the present application are described with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout. The content described in this application and shown in the drawings is only for enabling those skilled in the art to better understand and implement the technical solutions disclosed in this application, but the descriptions in the drawings and the specific embodiments are only exemplary, and this application is not limited thereto. Note that in the embodiments described below, sometimes the same reference numerals are used commonly between different drawings to represent the same parts or parts with the same functions, and their repeated descriptions are omitted. In some cases, similar reference numerals and letters are used to represent similar items, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0036] For ease of understanding, the positions, dimensions, ranges, etc. of the various structures shown in the drawings and the like sometimes do not represent the actual positions, dimensions, ranges, etc. Therefore, this disclosure is not limited to the positions, dimensions, ranges, etc. disclosed in the drawings and the like.

[0037] Figure 1 is a perspective view of a linear actuator according to the present invention;

[0038] Figure 2 is a cross-sectional view of the overall structure of a linear actuator according to a specific embodiment of the present application, which shows in detail each component included in the linear actuator and the cooperation and positional relationship between the components;

[0039] Figure 3 briefly shows Figure 2 an exploded view of the bearing at the rear end of the mandrel and the integral rear mount in, showing the main components between the worm gear and the rear mount;

[0040] Figure 4 shows a view after the main components between the worm gear and the rear mount are installed;

[0041] Figure 5 Schematically shows a cross-sectional view taken along line A-A in Figure 1 ;

[0042] Figure 6 Shows a cross-sectional view after installation of the main components between the worm gear and the rear mounting member;

[0043] Figure 7 Is a cross-sectional view showing a circumferential groove provided on the rear mounting member. Detailed Description of the Invention

[0044] Various exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure.

[0045] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present disclosure or its application or use. That is, the devices and methods herein are shown by way of example to illustrate different embodiments of the devices and methods in the present disclosure. However, those skilled in the art will understand that they merely illustrate exemplary ways in which the present disclosure can be implemented, rather than exhaustive ways.

[0046] Techniques, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered as part of the authorization specification.

[0047] In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0048] The preferred embodiments of the present application will now be specifically described with reference to the accompanying drawings. The Figure 1 Is a cross-sectional view of the overall structure of a linear actuator according to a specific embodiment of the present application, where the specific meanings of the reference numerals are as follows:

[0049] 1. - Rear mounting member;

[0050] 1' - Bearing receiving portion;

[0051] 1'' - Rear portion of the rear mounting member;

[0052] 2. - Bearing;

[0053] 3. - First stop;

[0054] 4. - Coupling;

[0055] 4′ - Large diameter part of the coupling

[0056] 4″ - Small diameter part of the coupling

[0057] 5. - Gasket

[0058] 6. - Braking part

[0059] 6′ - Extended end of the winding spring

[0060] 7. - Worm gear

[0061] 8. - Auxiliary bearing

[0062] 9. - Retaining element

[0063] 10. - Mandrel nut

[0064] 11. - Outer pipe fitting

[0065] 12. - Inner pipe fitting

[0066] 13. - Second stop

[0067] 14. - Washer

[0068] 15. - Front mounting part

[0069] 16. - Upper housing

[0070] 17. - Motor

[0071] 18. - Motor connection bolt

[0072] 19. - Motor connection bolt

[0073] 20. - Magnet

[0074] 21. - Clamping part

[0075] 22. - Safety nut

[0076] 23. - Mandrel

[0077] 24. - Sleeve

[0078] 25. - Braking part retaining portion

[0079] 26. - Slot

[0080] 27. - Circumferential groove

[0081] 28. - Motor retaining part.

[0082] For the purpose of convenient description, the present invention is attached Figure 2The "right side" along the longitudinal axis of the mandrel 23 is defined as the front side, and the opposite side is defined as the rear side.

[0083] See the attached Figure 1 , 2 , which generally show the positional cooperation relationship of the linear actuator of the present invention and its various components in the assembled state.

[0084] The linear actuator of the present invention includes: an upper housing 16; a front mount 15 having mounting holes connected to a fixing portion of a corresponding device (such as a rehabilitation bed); a rear mount 1 having mounting holes connected to another fixing portion of the device; a mandrel 23 longitudinally extending between the front mount 15 and the rear mount 1, wherein an external thread is formed on a part of the mandrel 23; a mandrel nut 10 having an internal thread formed thereon, and the internal thread is in threaded engagement with the external thread of the mandrel; an inner pipe member 12 disposed substantially parallel and coaxially outside the mandrel 23 and spaced apart from the mandrel at a certain distance, and the inner pipe member 12 functions as an actuating element, the rear end of which is connected to the mandrel nut 10 and the front end of which is connected to the front mount 15; an outer pipe member 11 surrounding the inner pipe member 12 at a certain distance and disposed substantially parallel and coaxially with the inner pipe member 12, and a track portion along which the mandrel nut 10 moves back and forth is formed on the outer pipe member 11; a motor 17 having an output shaft, and the output shaft is finally connected to a worm, and the worm meshes with a worm gear 7 fixed on the mandrel 23 to drive the mandrel. When the mandrel 23 is driven to rotate, the rotational motion of the mandrel 23 is converted into the back-and-forth linear motion of the mandrel nut 10, and the mandrel nut 10 pushes or pulls the inner pipe member 12, and thereby pushes or pulls the front mount 15, so that the mount 15 extends or retracts, thereby realizing the adjustment of the length, width or inclination of the device connected to the linear actuator.

[0085] As Figure 2 shown, the mandrel nut 10 is in the form of two parts with different diameters, wherein a part cooperating with the track portion on the outer pipe 11 is formed on the large-diameter portion at the rear shown in Figure 2 to facilitate the back-and-forth movement of the mandrel nut 10 along the track portion on the outer pipe member 11. The rear end of the inner pipe member 12 is fixedly installed (for example, by means of threading, adhesive or riveting) on the small-diameter portion at the front of the mandrel nut 10, and thus moves back and forth axially under the action of the mandrel nut 10.

[0086] The linear actuator is provided with a holding element 9, and the holding element 9 connects the rear mount 1 and the outer pipe member 11 together. In addition, a sleeve 24 is provided at the end of the outer pipe member facing the front mount, and the upper housing 16, the holding element 9, the outer pipe member 11, the sleeve 24 and the motor holder 28 are used to encapsulate the various components in the linear actuator.

[0087] A rigid second stopper 13 is sleeved on the right end (outer free end) of the mandrel 23, which limits the linear movement of the mandrel nut 10. A washer 14 is installed on the outer periphery of the second stopper 13, which slidably supports the inner periphery of the inner pipe fitting 12.

[0088] Preferably, the washer 14 is made of polyoxymethylene (POM).

[0089] See the appendix Figure 2 、 6 As shown in the figure, a coupling member 4 is fixedly installed on the threadless end of the mandrel 23 at the rear side of the worm gear 7, and it rotates integrally with the mandrel 23. The coupling member 4 is formed in a stepped shape, that is, divided into two parts with different diameters. The bearing 2 is installed on the small-diameter part 4″ (i.e., the part closest to the rear mounting member 1) of the stepped shape, while the brake member 6 is installed on the large-diameter part 4′ (i.e., the part closest to the worm gear 7) of the stepped shape; wherein, the brake member 6 is preferably a wound spring. The wound spring applies a torque to the mandrel 23 in the direction opposite to its rotation direction to decelerate the mandrel nut 10 when it moves forward to the end of its stroke.

[0090] Wherein, the coupling member 4 can also be formed into other shapes different from the stepped shape, for example, a cylindrical shape with a uniform diameter.

[0091] In the embodiment of the present application, the rear mounting member 1 as a whole is a single part made of a plastic material (such as nylon) with a certain hardness. The single part is formed into a rear part 1″ with a mounting hole and a bearing receiving part 1′ extending forward from the rear part. Wherein, the rear part 1″ with the mounting hole can be formed into two fork legs symmetrical with respect to the longitudinal axis of the mandrel as shown in the figure. However, the present application is not limited thereto. For example, the number of fork legs can be one or more than two, which depends on the installation requirements.

[0092] The bearing receiving part 1′ is a part of the rear mounting member 1, and its whole forms a generally cylindrical shape. As Figure 7 shown, a circumferential groove 27 is formed along the inner circumference of the bearing receiving part 1′, and a long strip-shaped opening along the longitudinal axis of the mandrel is formed on the side of the bearing receiving part 1′. The linear actuator further includes a brake member holding part 25 with a shape and size matching the long strip-shaped opening. A groove corresponding to the circumferential groove 27 formed on the inner circumference of the bearing receiving part 1′ is also formed on the arc-shaped inner side of the brake member holding part 25, and the two grooves form an integral annular groove after assembly.

[0093] As Figure 2 shown, along the axial direction of the linear actuator, on the mandrel and at the rear side of the bearing 2 ( Figure 2On the left side (in the figure) is arranged a gasket 5 for starting and stopping functions. It prevents the bearing from moving backward along the mandrel 23.

[0094] When installing the bearing 2, by applying a force to the bearing receiving portion 1′, since the bearing receiving portion 1′ is made of a material with a certain elasticity and due to the existence of the elongated opening on its side, the bearing receiving portion expands radially, thereby arranging the bearing 2 in place and placing the first stopper 3 in the circumferential groove 27 formed on the inner circumference of the bearing receiving portion. When the linear actuator is installed, the front side of the bearing 2 is restricted by the side of the larger diameter portion 4′ of the two different diameter portions of the coupling member 4 and the first stopper 3, thereby preventing it from moving forward relative to the mandrel 23.

[0095] When the coupling member 4 is a cylindrical shape with a uniform diameter, only the first stopper 3 restricts the forward movement of the bearing 2.

[0096] After the bearing 2 and the first stopper 3 are arranged in place in the bearing receiving cavity, the brake member holding portion 25 is installed into the elongated opening formed on the side of the bearing receiving portion 1′, and the groove on the inner side of the brake member holding portion 25 is made continuous with the groove formed on the inner circumference of the bearing receiving portion, so that the groove on the inner side of the brake member holding portion 25 also accommodates a part of the first stopper 3. This structure ensures the cylindricity and concentricity of the bearing receiving cavity.

[0097] Combined with the attached Figure 2 、 4 Figures 5 and 6, the arrangement and fixation of the brake member 6 in the linear actuator of the present application in the present invention will be described.

[0098] The brake member 6 is preferably a wound spring, but the present application is not limited thereto. The wound spring is installed on the larger diameter portion 4′ of the coupling portion 4 and is between the stopper 3 and the worm wheel 7, and one end of the wound spring is fixed to the larger diameter portion 4′ by fusion welding, brazing or other means, and its extended end 6′ extends outward (see attached Figure 5 Figure), and is fixed in the following manner: One side of the brake member holding portion 25 and one side of the elongated opening formed on the side of the bearing receiving portion form a clamping portion 26, and the clamping portion is preferably formed by corresponding card slots on both of them. The extended end 6′ of the wound spring is held in the clamping portion 26. However, the clamping portion 26 in the present application is not limited to the form of a card slot.

[0099] In particular, the coupling member 4 is not necessary, and the bearing 2 and the brake member 6 can also be directly installed on the mandrel.

[0100] In the attached Figure 4 、 5The situation where the brake member holding portion 25 is installed in the elongated opening to hold in place the radially outwardly extending end of the winding spring is shown.

[0101] Preferably, along the axial direction of the mandrel, a safety nut 22 is disposed around the mandrel 23 at the rear side of the mandrel nut 10. When the mandrel nut 10 wears due to functional failure or long-term application, or slips due to excessive load, the safety nut 22 acts to push against the mandrel nut 10, enabling the mandrel nut to operate safely, thereby extending the operating life of the linear actuator and ensuring the operating safety of the linear actuator.

[0102] Further preferably, a cavity is provided between the large-diameter portion of the mandrel nut 10 and the mandrel 23, and the safety nut 22 is disposed in this cavity and is held on the mandrel 23 by the mandrel nut 10 and rotates together with the mandrel nut 10 on the mandrel 23. For specific reference, please see the appendix Figure 2 .

[0103] In a specific embodiment, the motor 17 is connected to the motor holding member 28 of the linear actuator through motor connection bolts 18, 19.

[0104] In a specific embodiment, an auxiliary bearing 8 is provided on the radially outer portion of the base portion of the worm wheel 7 mounted on the mandrel 23. The auxiliary bearing 8 is pressed between the base portion of the worm wheel 7 and the upper housing 16, thereby maintaining the straightness of the mandrel during the operation of the linear actuator.

[0105] Adjacent to the base of the worm wheel 7, a magnet 20 supported by a clamping member 21 is provided. The magnet 20 is connected to the electronic control device of the linear actuator (such as a printed circuit board (PCB board), not shown in the figure). The electronic control device calculates the number of turns of the mandrel rotation based on the induction of the magnet 20 on the rotation of the mandrel 23, thereby controlling the movement amount of the mandrel nut 10 along the mandrel 23. The magnet 20 is fixed by the clamping member 21.

[0106] Preferably, both the bearing 3 and the auxiliary bearing 8 are ball bearings, but the present application is not limited thereto.

[0107] The present invention also relates to an adjustable device including the above linear actuator. Among them, the front mounting member and the rear mounting member of the linear actuator are respectively fixedly mounted on the corresponding mounting portions of the adjustable device for adjusting the size or inclination of the adjustable device.

[0108] Preferably, the adjustable device is a rehabilitation bed or an operating bed or a furniture-type device.

[0109] The technical solution of the present invention has been described in detail above with reference to the accompanying drawings.

[0110] In the description and claims, words such as "front", "rear", "left", "right", "upper", "lower", etc., if present, are used for descriptive purposes and not necessarily to describe a fixed relative position. It should be understood that such words are interchangeable under appropriate circumstances so that the embodiments of the present disclosure described herein, for example, can operate in other orientations different from those shown or otherwise described herein.

[0111] As used herein, the word "substantially" means including any minor variations caused by design or manufacturing tolerances, environmental effects, and / or other factors.

[0112] It should also be understood that when the term "comprising / including" is used herein, it indicates the presence of the stated features, integers, steps, operations, units, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, units, and / or components and / or combinations thereof.

[0113] Although exemplary embodiments of the present disclosure have been described, those skilled in the art should understand that various changes and modifications can be made to the exemplary embodiments of the present disclosure without departing from the spirit and scope of the present disclosure in essence. Therefore, all such changes and modifications are included within the scope of protection of the present disclosure defined by the claims. The present disclosure is defined by the appended claims, and equivalents of these claims are also included.

Claims

1. A linear actuator, characterized in that, the linear actuator comprises: an upper housing; a spindle disposed between a front mount and a rear mount, a worm gear being fixedly mounted on the spindle, and external threads being formed on a partial outer surface of the spindle; a motor and a transmission mechanism, the transmission mechanism including a worm that meshes with the worm gear, the motor being disposed in a motor holder, and the motor holder being connected to the upper housing; a spindle nut disposed on the spindle, an internal thread of the spindle nut meshing with the external thread of the spindle; an inner pipe fitting, one end of the inner pipe fitting being attached to the spindle nut and the other end thereof being attached to the front mount, the inner pipe fitting being disposed parallel to the spindle at a certain interval around the spindle; an outer pipe fitting disposed parallel to the inner pipe fitting at a certain interval around the inner pipe fitting; wherein, the rear mount is an integral part made of a plastic material with a certain hardness, the rear mount includes a bearing receiving portion extending along the longitudinal axis of the spindle, a circumferential groove being formed on the inner circumference of the bearing receiving portion and a long strip-shaped opening being formed on one side thereof, a brake member holding portion being clamped in the long strip-shaped opening, a groove being formed on the inner side of the brake member holding portion, and the groove on the brake member holding portion and the circumferential groove on the bearing receiving portion forming an annular groove; a bearing disposed in the bearing receiving portion; a first stopper disposed in the annular groove formed by the circumferential groove on the bearing receiving portion and the groove on the brake member holding portion; a brake member held by the brake member holding portion, wherein, the brake member applies a torque in a direction opposite to the rotation direction of the spindle to decelerate the spindle nut when the spindle nut moves forward to the stroke end of the spindle nut.

2. The linear actuator according to claim 1, characterized in that, an auxiliary bearing is provided on a base portion of the worm gear fixedly mounted on the spindle, and the auxiliary bearing is pressed between the base portion of the worm gear and the upper housing of the linear actuator.

3. The linear actuator according to claim 1, characterized in that, a cavity is formed between the rear portion of the spindle nut and the spindle, and a safety nut that is in threaded engagement with the spindle is disposed in the cavity, and the safety nut is held on the spindle by the rear portion of the spindle nut.

4. The linear actuator according to claim 1, characterized in that, the brake member is a wound spring, a coupling member is fixedly mounted on the rear end portion of the spindle, the coupling member has a stepped structure, the bearing is mounted on a small diameter portion of the stepped structure, and the wound spring is mounted on a large diameter portion of the stepped structure.

5. The linear actuator according to claim 4, characterized in that, a clamping portion formed by one side of the brake member holding portion and the long strip-shaped opening fixes an outward extending end of the wound spring, and the other end of the wound spring is fixed on the coupling member.

6. The linear actuator according to claim 5, characterized in that, The clamping part is formed by a clamping groove on the brake part holding part and a corresponding clamping groove on the one side of the long strip-shaped opening.

7. The linear actuator according to claim 1, wherein, the spindle nut is engaged with a linear guiding track on the outer pipe fitting.

8. The linear actuator according to claim 1, wherein, the front end of the spindle is supported in the inner pipe fitting by a second stop.

9. The linear actuator according to claim 1, wherein, the rear mounting member includes a mounting portion connected to the bearing receiving portion and extending along the longitudinal axis of the spindle, and the mounting portion includes two fork legs symmetrically arranged with respect to the longitudinal axis of the spindle.

10. An adjustable device, wherein, the adjustable device includes the linear actuator according to any one of claims 1-9, and the front mounting member and the rear mounting member of the linear actuator are respectively mounted on corresponding mounting portions of the adjustable device to adjust the size or inclination of the adjustable device.

11. The adjustable device according to claim 10, wherein, the adjustable device is a rehabilitation bed or an operating bed or a furniture-type device.

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