CN113708555A - Electric push rod - Google Patents

Electric push rod Download PDF

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Publication number
CN113708555A
CN113708555A CN202010436919.0A CN202010436919A CN113708555A CN 113708555 A CN113708555 A CN 113708555A CN 202010436919 A CN202010436919 A CN 202010436919A CN 113708555 A CN113708555 A CN 113708555A
Authority
CN
China
Prior art keywords
axial part
main shaft
bearing
axial
screw
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202010436919.0A
Other languages
Chinese (zh)
Inventor
周世祥
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Linak Shenzhen Actuator System Ltd
Linak AS
Original Assignee
Linak AS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linak AS filed Critical Linak AS
Priority to CN202010436919.0A priority Critical patent/CN113708555A/en
Publication of CN113708555A publication Critical patent/CN113708555A/en
Pending legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/06—Means for converting reciprocating motion into rotary motion or vice versa
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H37/00—Combinations of mechanical gearings, not provided for in groups F16H1/00 - F16H35/00
    • F16H37/12—Gearings comprising primarily toothed or friction gearing, links or levers, and cams, or members of at least two of these types
    • F16H37/124—Gearings comprising primarily toothed or friction gearing, links or levers, and cams, or members of at least two of these types for interconverting rotary motion and reciprocating motion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/22—Toothed members; Worms for transmissions with crossing shafts, especially worms, worm-gears
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears
    • H02K7/1163—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears where at least two gears have non-parallel axes without having orbital motion
    • H02K7/1166—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears where at least two gears have non-parallel axes without having orbital motion comprising worm and worm-wheel

Abstract

The invention relates to an electric push rod, which comprises a shell, an outer pipe, an inner pipe, a screw spindle, a spindle nut, a motor and a transmission device, wherein the transmission device comprises a worm and a worm wheel; a bearing for supporting the screw main shaft is mounted on an outer surface of the third axial portion of the worm wheel to support the screw main shaft in the housing; one side of the bearing is abutted against the wall surface of the radial extension step between the second axial part and the third axial part, and the other side of the bearing is abutted against an end fastener arranged at the tail end of the main shaft of the screw rod, so that the bearing is clamped and fixed.

Description

Electric push rod
Technical Field
The invention relates to an electric push rod.
Background
An electric push rod, also called a linear actuator, is a driving device that converts a rotary motion into a linear reciprocating motion. The electric push rod can be applied to various environments such as hospitals, offices, factories, families and the like, and is used for moving heavy objects such as beds, tables, chairs, medical equipment, industrial machinery and the like in a push-pull, lifting, tilting and the like manner.
Generally, the electric push rod mainly includes a motor, a screw, a nut, a transmission, a brake, and the like.
In one prior art power putter, in order to prevent relative rotation between the two parts of the transmission, a hollow pin or clamping sleeve made of metal is used, and a key-and-groove engagement is used. The electric push rod has more parts and higher manufacturing cost.
In order to improve the above-mentioned electric putter, there has been proposed a prior art electric putter in which a fastening member is inserted into a hole of one part of a transmission and welded to the other part. The manufacturing process of the electric push rod is complicated and the manufacturing cost is correspondingly high due to the need of forming holes on the components.
In addition, in another prior art electric putter, the transmission consists of a worm wheel and a worm. The worm wheel is fixed to the screw via an intermediate coupling in the form of a sleeve. Because the spare part is more, manufacturing cost is higher too.
Disclosure of Invention
The invention provides an electric push rod, which adopts fewer parts, eliminates stress concentration points which are easy to damage and can solve the problems in the prior art.
According to the present invention, there is provided an electric putter including:
a housing;
an outer tube connected in the housing;
an inner tube disposed within the outer tube;
a screw spindle extending within the inner tube;
the main shaft nut is meshed with the screw main shaft and is connected with the inner pipe;
a motor installed outside the housing;
the transmission device comprises a worm arranged on an output shaft of the motor and a worm wheel directly fixedly arranged on a main shaft of the screw rod through thread meshing, and the worm is meshed with the worm wheel so as to convert the rotary motion of the motor and the main shaft of the screw rod into linear reciprocating motion of a main shaft nut and an inner pipe guided by an outer pipe;
it is characterized in that the preparation method is characterized in that,
the worm wheel is provided with a first axial part, a second axial part and a third axial part which are sequentially arranged in the axial direction of the main shaft of the screw rod, the second axial part is positioned between the first axial part and the third axial part, the diameter of the first axial part is larger than that of the second axial part, the diameter of the second axial part is larger than that of the third axial part, and therefore a radial extending step wall surface is formed between the first axial part and the second axial part and between the second axial part and the third axial part;
a bearing for supporting the screw main shaft is mounted on an outer surface of the third axial portion of the worm wheel to support the screw main shaft in the housing;
one side of the bearing is abutted against the wall surface of the radial extension step between the second axial part and the third axial part, and the other side of the bearing is abutted against an end fastener arranged at the tail end of the main shaft of the screw rod, so that the bearing is clamped and fixed.
According to an embodiment of the invention, the housing rear end further comprises a rear mounting to which the load on the screw spindle is transferred via bearings.
According to one embodiment of the invention, the bearing rotates with the worm gear.
According to an embodiment of the invention, the rear end of the third axial portion is at least partially flush with the rear end of the screw spindle.
According to an embodiment of the invention, the end fastener abuts a tip of the third axial portion and is welded to a tip of the screw spindle.
According to one embodiment of the invention, the end fastener is a multi-lobular star-shaped flat plate.
According to an embodiment of the invention, the housing rear end further comprises a rear mounting abutting the end fastener and/or the bearing.
According to an embodiment of the present invention, the electric putter further includes a brake device fixed to the second axial portion of the worm wheel.
According to an embodiment of the present invention, the brake device includes a brake drum, a front side of which abuts against a radially extending step wall surface between the first axial portion and the second axial portion, and a rear side of which is abutted by the bearing to prevent rotation.
According to an embodiment of the invention, the brake device further comprises a spring arranged around the brake drum, the spring releasing its grip on the brake drum when the spindle nut is moved linearly outwards and the spring being tensioned around the brake drum to apply the braking force when the spindle nut is retracted.
According to the electric push rod provided by the invention, the number of parts can be reduced, the manufacturing process is simplified, the manufacturing cost is saved, and meanwhile, the electric push rod can be stably and effectively operated.
Drawings
Objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description of the embodiments with reference to the accompanying drawings. Furthermore, the various elements of the drawings are not necessarily to scale; on the contrary, the dimensions of the various elements in the figures may be exaggerated or minimized as appropriate to more clearly illustrate the embodiments of the present invention.
The invention is further described with reference to the following figures and examples, in which like reference numerals refer to like elements.
Fig. 1 is a plan view of the electric putter of the present invention with the upper half of the housing removed to show the internal construction of the housing.
Fig. 2 is a longitudinal partial sectional view of the electric putter of fig. 1 along the main axis of the screw, with details omitted in order to show the gist of the invention more clearly.
Fig. 3 is a right side end view of the power putter of fig. 2.
Fig. 4 is an overall external view of the electric putter of the present invention.
Fig. 5 is a longitudinal cross-sectional view of fig. 4 taken along the axis of the main shaft of the screw.
Detailed Description
The terms used herein should be understood and interpreted to have a meaning consistent with their understanding by those skilled in the art, rather than a specific definition that is different from the ordinary meaning as understood by those skilled in the art. Specific definitions will be explicitly indicated in the specification.
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the sizes, materials, shapes, relative arrangement relationships, and the like of the constituent elements described in the embodiments may be appropriately changed according to the configuration, various conditions, and the like of the apparatus to which the present invention is applied. Therefore, the sizes, materials, shapes, relative arrangement relationships, and the like of the constituent elements described in the embodiments are not intended to limit the scope of the present invention to the following embodiments.
Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating relative importance or as indicating a number of technical features.
As shown in fig. 1 and 4, the electric putter of the present invention includes a housing 5, and the housing 5 may be made of plastic. An outer tube 6 is attached in the housing 5, and the outer tube 6 may protrude out of the housing 5. The inner tube is telescopically guided by the outer tube 6 along a longitudinal axis within the outer tube 6. One end of the outer tube 6 may comprise a bushing for guiding the inner tube. Further, a rear mounting 13 is provided at the rear end of the housing 5 and a front mounting 14 is provided at the front end of the inner tube to facilitate mounting of the power putter in use.
The electric putter comprises a motor, e.g. a reversible motor, and may be a direct current motor or an alternating current motor. The motor is arranged at the bottom of the shell, and the axial direction of the output shaft of the motor is vertical to the longitudinal axis of the outer tube 6.
As shown in fig. 2 and 5, the electric putter further comprises a screw spindle 1 extending inside the inner tube. The extension of the motor output shaft is designed as a worm 7 to engage with a worm wheel 2 mounted near the rear end of the spindle 1 of the screw. The worm wheel 2 is fixed so as not to rotate relative to the screw main shaft 1. Thus, when the worm wheel 2 rotates, the screw main shaft 1 also rotates.
The worm wheel 2 and the worm 7 form a transmission device of the electric push rod. However, the present invention is not limited to worm and worm gear transmissions, and other types of transmissions known in the art, such as gear train transmissions, rack and pinion transmissions, etc., may be used.
A spindle nut (not shown) is arranged inside the outer tube 6, having an internal thread to mesh with the external thread of the screw spindle 1. The rear end of the inner tube is fastened to the spindle nut, for example by means of threads or other fastening means. The spindle nut is fixed against rotation relative to the screw spindle 1, the outer tube 6 and the inner tube, either by engagement with the outer tube (direct fixation) or when the electric push rod is fixed to the object to be moved, e.g. a bed (indirect fixation).
Thus, after the motor is started, the worm wheel 2 starts to rotate under the drive of the worm 7 of the motor output shaft, so that the screw spindle 1 rotates, the rotation motion of the screw spindle 1 is converted into the linear motion of the spindle nut guided by the outer tube 6 in the outer tube 6, and the inner tube and the spindle nut perform linear telescopic motion along the longitudinal axis in the outer tube 6. When the motor rotates forwards, the inner pipe extends forwards; when the motor rotates reversely, the inner tube retracts backwards.
According to the electric push rod of the invention, the worm wheel 2 is directly fixed on the screw main shaft 1 and is coaxial with the screw main shaft 1. The worm wheel 2 is directly meshed with the screw spindle 1 through threads without an additional intermediate connecting piece.
In order to prevent the spindle nut from falling off the front end of the screw spindle 1, a stopper may be further provided at the front end of the screw spindle 1.
According to the invention, the worm wheel 2 has a first axial portion 8, a second axial portion 9 and a third axial portion 10 arranged in this order in the axial direction of the spindle 1, the second axial portion 9 being located between the first axial portion 8 and the third axial portion 10. The diameter of the first axial portion 8 is larger than the diameter of the second axial portion 9, and the diameter of the second axial portion 9 is larger than the diameter of the third axial portion 10, so that radially extending stepped wall surfaces are formed both between the first and second axial portions 8 and 9 and between the second and third axial portions 9 and 10. The rear end of the third axial portion 10 is at least partially flush with the rear end of the screw spindle 1.
A bearing 3 supporting the screw spindle 1 is mounted on an outer surface of the third axial portion 10 of the worm wheel 2 for supporting the screw spindle 1 in the housing 5. The bearing 3 may be a ball bearing, for example. The load on the screw spindle 1 is transmitted to the rear mounting 13 via the bearing 3.
According to the present invention, the end fastener 4 provided at the rear end of the screw spindle 1 abuts the rear end of the third axial portion 10 and is welded to the rear end of the screw spindle 1. The end fastener 4 is made of metal and the spindle 1 of the screw is made of metal. The front side of the bearing 3 mounted on the third axial portion 10 abuts against the radially extending stepped wall surface between the second axial portion 9 and the third axial portion 10, and the rear side is abutted by the end fastener 4, whereby the bearing 3 is clamped and fixed. The bearing 3 rotates together with the worm wheel 2.
Thus, the worm wheel 2 is fixed so as not to rotate relative to the screw main shaft 1. After the worm wheel 2 is directly engaged with the screw main shaft 1 by the screw thread as described above, the worm wheel 2 and the screw main shaft 1 are fixed to each other in the axial direction and the circumferential direction with respect to the longitudinal axis of the screw main shaft 1.
As shown in fig. 3, the end fastener 4 is a trilobal star-shaped flat plate. However, the present invention is not limited to this shape. The end fastener 4 may have a multilobal shape with three or more leaves.
The rear mounting 13 abuts the rear side of the end fastener 4 and/or the bearing 3. By clamping on both sides of the bearing 3 in the manner described above, push-pull forces can be transmitted between the front mounting 14 and the rear mounting 13. More specifically, the thrust force acting on the front mount 14 will be transmitted to the rear mount 13 through the inner tube, the spindle nut, the screw spindle 1, the worm wheel 2, the bearing 3.
The electric putter of the present invention may further include a brake device. As an example, as shown in fig. 1, the brake device includes a cylindrical brake drum 11 and a spring 12. The brake drum 11 is fixed to the second axial portion 9 of the worm wheel 2. The front side of the brake drum 11 abuts a radially extending stepped wall surface between the first axial portion 8 and the second axial portion 9, and the rear side is abutted by the bearing 3 to prevent rotation. The spring 12 of the brake device is arranged around the brake drum 11. One end of the spring 12 is bent radially outward and held in a groove of the rear mounting. When the spindle nut is moved linearly outward (i.e., pushing the load), the spring 12 releases the grip on the brake drum 11. When the spindle nut is retracted, the spring 12 is tensioned around the brake drum 11, applying a braking force to the brake drum 11 and thus to the screw spindle 1.
The particular features, structures, materials, or characteristics described above may be combined in any suitable manner in this specification.
While the present invention has been described with reference to the above exemplary embodiments, it will be understood by those skilled in the art that various modifications may be made to the specific embodiments disclosed above, and the present invention is not limited to the above exemplary embodiments. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (10)

1. An electric putter comprising:
a housing;
an outer tube connected in the housing;
an inner tube disposed within the outer tube;
a screw spindle extending within the inner tube;
the main shaft nut is meshed with the screw main shaft and is connected with the inner pipe;
a motor installed outside the housing;
the transmission device comprises a worm arranged on an output shaft of the motor and a worm wheel directly fixedly arranged on a main shaft of the screw rod through thread meshing, and the worm is meshed with the worm wheel so as to convert the rotary motion of the motor and the main shaft of the screw rod into linear reciprocating motion of a main shaft nut and an inner pipe guided by an outer pipe;
it is characterized in that the preparation method is characterized in that,
the worm wheel is provided with a first axial part, a second axial part and a third axial part which are sequentially arranged in the axial direction of the main shaft of the screw rod, the second axial part is positioned between the first axial part and the third axial part, the diameter of the first axial part is larger than that of the second axial part, the diameter of the second axial part is larger than that of the third axial part, and therefore a radial extending step wall surface is formed between the first axial part and the second axial part and between the second axial part and the third axial part;
a bearing for supporting the screw main shaft is mounted on an outer surface of the third axial portion of the worm wheel to support the screw main shaft in the housing;
one side of the bearing is abutted against the wall surface of the radial extension step between the second axial part and the third axial part, and the other side of the bearing is abutted against an end fastener arranged at the tail end of the main shaft of the screw rod, so that the bearing is clamped and fixed.
2. The power putter of claim 1, wherein the housing rear end further includes a rear mount, the load on the screw spindle being transmitted to the rear mount through the bearing.
3. The power putter of claim 1, wherein the bearing rotates with the worm gear.
4. The power putter of claim 1, wherein a rear end of the third axial portion is at least partially flush with a rear end of the screw spindle.
5. The power putter of claim 1, wherein the end fastener abuts a distal end of the third axial portion and is welded to a distal end of the screw spindle.
6. The power putter of claim 1 wherein the end fastener is a multi-lobed star plate.
7. The power putter of claim 1, wherein the housing rear end further includes a rear mount, the rear mount abutting the end fastener and/or the bearing.
8. The power putter of claim 1, further comprising a brake secured to the second axial portion of the worm gear.
9. The power putter of claim 8, wherein the brake includes a brake drum, a front side of the brake drum abutting a radially extending step wall surface between the first and second axial portions, and a rear side being abutted by the bearing to prevent rotation.
10. The power putter of claim 9, wherein the brake further includes a spring disposed about the brake drum, the spring releasing the grip on the brake drum when the spindle nut is moved linearly outward and the spring tensioning about the brake drum to apply the braking force when the spindle nut is retracted.
CN202010436919.0A 2020-05-21 2020-05-21 Electric push rod Pending CN113708555A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010436919.0A CN113708555A (en) 2020-05-21 2020-05-21 Electric push rod

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010436919.0A CN113708555A (en) 2020-05-21 2020-05-21 Electric push rod

Publications (1)

Publication Number Publication Date
CN113708555A true CN113708555A (en) 2021-11-26

Family

ID=78646221

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010436919.0A Pending CN113708555A (en) 2020-05-21 2020-05-21 Electric push rod

Country Status (1)

Country Link
CN (1) CN113708555A (en)

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