One-way freewheel for linear drive motor

Abstract

The application discloses a one-way self-locking device for a linear driving motor, which comprises a friction ring sleeved on the tail end of a motor rotating shaft away from the output end of the motor rotating shaft, a torsion spring sleeved on the friction ring and a fixing base sleeved outside the torsion spring and fixed on a first end cover of the motor, one end of the torsion spring is fixed on the fixing base, and the other end of the torsion spring is fixed on the friction ring; the friction ring is an elastic circular ring composed of a plurality of arc-shaped pieces connected in a head-to-tail mode, the friction ring is in interference fit with the motor rotating shaft and has a pre-tightening friction force; the friction ring and the fixing base are provided with a torsion spring tension structure which is capable of releasing the torsion spring when the motor rotating shaft rotates in one direction and rotating the torsion spring and circularly compressing the friction ring to realize one-way self-locking when the motor rotating shaft rotates in the opposite direction, and the torsion spring gap is sleeved on the friction ring. The one-way self-locking device has the advantages that the friction ring itself has a radial elastic force, the friction surface is complete and continuous, the friction force is stable, and the wear is relatively small.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of linear drive, in particular to a one-way self-locking device for linear drive motor. BACKGROUND

[0002] Linear drive mechanism is widely used, such as in the technical field of electric lifting table, the motor of linear drive mechanism is also called linear drive motor, which drives the screw rod in the screw nut pair to rotate through the worm and the worm gear to realize the lifting or lowering of the table leg, and then drives the lifting or lowering of the table board. In order to slow down the speed in one direction, such as to slow down the speed when lowering to make the lowering process smooth and the customer experience good, and / or to prevent the automatic sinking of the table board due to the overload of the table board when the motor does not rotate, a one-way self-locking device is generally provided. During the lifting process, the one-way self-locking device does not act, so the transmission efficiency is large and the speed is fast; during the lowering process, the one-way self-locking device acts, but the driving force of the motor is greater than the friction force of the self-locking device, the transmission efficiency is relatively weak, and the speed is relatively slow; if the load of the table board is too large or the table board vibrates, the screw rod rotates, which drives the worm gear, the worm and the rotating shaft of the motor to rotate, but at this time the friction force of the self-locking device is greater than the rotating force of the rotating shaft, so the self-locking device is locked to prevent the automatic sinking of the table board.

[0003] The traditional one-way self-locking device for linear drive motor adopts a torsion spring which is sleeved on the rotating shaft at the end of the motor shaft away from the worm to realize the self-locking of the rotating shaft of the motor, but it is easy to cause the torsion spring and the rotating shaft of the motor to generate heat by friction, which causes the torsion spring to anneal and quickly wear out, shortening the service life of the torsion spring; and since the effective contact area between the torsion spring and the rotating shaft of the motor is small during the self-locking process of the torsion spring, the self-locking force is not enough and is easy to fail.

[0004] The skilled person increases a ring-shaped friction member between the torsion spring and the motor shaft, the ring-shaped friction member has a notch, or is composed of several arc-shaped plates, the torsion spring rotates to generate radial pressure on the ring-shaped friction member to realize self-locking or braking. Compared with the traditional one-way self-locking device, the phenomenon of heat generation by friction causing the torsion spring to anneal does not occur, and the service life of the torsion spring is relatively prolonged.

[0005] But the above prior art for linear drive motor on one-way self-locking device still has the following shortcomings: annular friction member is a circular sleeve with a gap or annular friction member is composed of several arc blocks, therefore: 1. From the axial, relative to the traditional torsional spring brake structure, the linear contact area is increased, but from the circumferential, the friction surface is still incomplete, discontinuous, not comprehensive, not uniform, not stable, the force is inconsistent, the self-locking force is still not enough, and the local friction of the line affects the service life of the annular friction member. 2. The annular friction member itself does not have radial elastic force, and relies on the torsional spring to provide pre-warning friction force from beginning to end, and the torsional spring is always in working state and is easy to fatigue, which affects the self-locking effect and service life of the torsional spring. 3. Since the annular friction member itself does not produce radial elastic deformation, the pre-warning force is entirely relied on the torsional spring, so the size and mechanical properties of the torsional spring are required to be very strict and precise, the machining precision is required to be high, the machining difficulty is large, the material cost and machining cost are high, and in order to pursue the friction surface, a structure of multiple arc blocks is generally adopted, but the installation is relatively troublesome. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a one-way self-locking device for linear drive motor, which has radial elastic force, complete and continuous friction surface, stable friction force and relatively small wear.

[0007] The technical solution of the present application is to provide a one-way self-locking device for linear drive motor, which comprises a friction ring fitted on the tail end of the motor rotating shaft away from the output end of the motor rotating shaft, a torsional spring fitted on the friction ring, and a fixed seat fitted outside the torsional spring and fixedly connected to the first end cover of the motor. One end of the torsional spring is fixedly connected to the fixed seat, and the other end of the torsional spring is fixedly connected to the friction ring. The friction ring is an elastic circular ring composed of multiple arc-shaped pieces connected end to end, and the friction ring is in interference fit with the motor rotating shaft to have pre-tightening friction force. The friction ring and the fixed seat have a torsional spring tension structure that releases when the motor rotating shaft rotates in one direction, and tightens and compresses the friction ring when the motor rotating shaft rotates in the opposite direction to realize one-way self-locking.

[0008] After adopting the above structure, the one-way self-locking device for linear drive motor has the following advantages:

[0009] The elastic circular ring is composed of a plurality of arc-shaped pieces connected head to tail, which can produce radial elastic deformation, and the elastic circular ring is in interference fit with the motor shaft to have pre-tightening friction, when the shaft rotates in one direction, the torsion spring is loosened, and only the pre-warning friction of the elastic friction ring exists on the shaft, which basically does not affect the output of the rotating energy of the shaft, and the transmission efficiency is large and the speed is fast; when the shaft rotates in the opposite direction, the torsion spring is tightened and the annular friction ring is compressed to achieve one-way self-locking, but the motor driving force is greater than the friction of the self-locking device during the descending process, the transmission efficiency is relatively weak, and the speed is relatively slow, which meets the requirement of slow and stable descending and improves the good mental experience of the customer; when the motor stops rotating and the load needs to be braked, such as when the load of the table top of the electric lifting table is too large or the table top vibrates, the screw rod rotates, driving the worm, the worm gear and the shaft of the motor to rotate, but the friction between the friction ring under the annular compression of the torsion spring and the shaft of the motor is greater than the rotating force of the shaft, so that the self-locking or braking is achieved to prevent the table top from automatically sinking.

[0010] The friction surface of the friction ring of the one-way self-locking device is complete, continuous, comprehensive, uniform, stable, and consistent in force, the elastic deformation performance of the friction ring is good, the self-locking force of the self-locking device is strong, and stable, continuous and durable friction force is provided for the motor shaft, thereby improving the self-locking performance of the linear drive mechanism.

[0011] The phenomenon of local wear caused by local friction of the friction ring is effectively prevented, and the service life of the friction ring is greatly prolonged. Moreover, the torsion spring does not have a pre-warning force and is movably fitted or clearance fitted outside the friction ring, thereby overcoming the defect that the torsion spring is always in a working state and is prone to fatigue, which affects the self-locking efficiency and service life of the torsion spring, i.e. the self-locking efficiency of the torsion spring is greatly improved and the service life of the torsion spring is greatly prolonged.

[0012] Since the friction ring has a pre-tightening force and does not need the torsion spring to provide a pre-warning force, and the torsion spring only needs to provide a ring force to reduce the inner diameter of the friction ring in the one-way self-locking state, the requirements for the size and mechanical properties of the torsion spring are not very strict and precise, the machining precision requirement is relatively low, the machining difficulty is relatively small, the material cost and machining cost are relatively low, and the installation of the friction ring, the torsion spring and the fixing seat is simple, convenient and labor-saving.

[0013] Further, the torsion spring is clearance fitted on the friction ring. After the above structure is adopted, the requirements for the size and mechanical properties of the torsion spring, the machining precision and the like are further reduced, and the machining difficulty of the torsion spring is relatively small and the material cost and machining cost are further reduced.

[0014] Further, the specific structure of the head-to-tail connection is that two single-arc-shaped pieces are connected at the top to form an n-shaped concave arc-shaped piece, two single-arc-shaped pieces are connected at the bottom to form a U-shaped concave arc-shaped piece, and the two are arranged in sequence and continuously until a complete and continuous elastic circular ring is formed. After the above structure is adopted, the technical effects of the friction ring, such as complete friction surface, continuous and comprehensive in the circumferential and axial directions, uniform and stable, consistent force, good elastic deformation performance of the friction ring, and strong self-locking force of the self-locking device, are further ensured from the shape and structure.

[0015] Further, the n-shaped concave arc-shaped piece is 6-8 pieces, and the U-shaped concave arc-shaped piece is also 6-8 pieces. After the above structure is adopted, the technical effects of the friction ring, such as complete friction surface, continuous and comprehensive in the circumferential and axial directions, uniform and stable, consistent force, good elastic deformation performance of the friction ring, and strong self-locking force of the self-locking device, are further ensured from the number and ring density.

[0016] Further, the lower end of the n-shaped concave arc-shaped piece is a horn opening, and the upper end of the U-shaped concave arc-shaped piece is a horn opening. After the above structure is adopted, the technical effects of the friction ring, such as complete friction surface, continuous and comprehensive in the circumferential and axial directions, uniform and stable, consistent force, good elastic deformation performance of the friction ring, and strong self-locking force of the self-locking device, are further ensured from the mechanical properties.

[0017] Further, the torsional spring tension structure is that the bottom of the friction ring has a radial protrusion, the radial protrusion has a hole for inserting the lower end of the torsional spring, the wall of the central hole of the fixed seat has an axial groove for accommodating the upper end of the torsional spring, the bottom of the central hole of the fixed seat has an arc-shaped accommodation cavity formed between two limiting blocks for the rotation of the radial protrusion of the friction ring within a range of 90°-120°, and when the elastic friction ring with pre-tightening force is rotated in one direction, the torsional spring is loosened and retained by the first limiting block, and when the elastic friction ring with pre-tightening force is rotated in the opposite direction, the torsional spring is tightened and circularly compresses the friction ring and is retained by the second limiting block. After the above structure is adopted, the connection of the two ends of the torsional spring with the fixed seat and the friction ring is more stable and reliable, and the working process of the torsional spring rotating clockwise to loosen or counterclockwise to tighten under the pre-warning force of the friction ring is more stable and reliable. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the one-way self-locking device of the linear drive motor according to the present application (screws are not shown).

[0019] Figure 2 is Figure 1 is an enlarged structural schematic diagram of the one-way self-locking device of the linear drive motor according to the present application (the motor part is omitted).

[0020] Figure 3It is the explosion structure schematic diagram of the one-way self-locking device of the linear drive motor of the present application (screws are not drawn).

[0021] Figure 4 It is Figure 3 The fixed seat in the enlarged structure schematic diagram of the front view.

[0022] Figure 5 It is Figure 3 The torsional spring in the enlarged structure schematic diagram of the front view.

[0023] Figure 6 It is Figure 3 The friction ring in the enlarged structure schematic diagram of the front view.

[0024] Figure 7 It is Figure 3 The friction ring in the enlarged structure schematic diagram of the front view.

[0025] Figure 8 It is the friction ring in another specific structure in the present application.

[0026] The figure shows: 1, tail end, 2, axial groove, 3, fixed seat, 4, motor first end cover, 5, motor stator, 6, motor second end cover, 7, output end, 8, radial protrusion, 9, lower end of torsional spring, 10, second limiting block, 11, first limiting block, 12, arc-shaped accommodating cavity, 13, motor rotating shaft, 14, torsional spring, 15, friction ring, 16, center hole wall, 17, upper end of torsional spring, 18, insertion hole, 19, trumpet mouth, 20, U-shaped inner recessed arc-shaped piece, 21, n-shaped inner recessed arc-shaped piece, 22, integral inner recessed arc-shaped piece. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application will be further described below in conjunction with the accompanying drawings. It is declared here that the description of these specific embodiments is used to help understand the present application, but does not constitute a limitation on the present application. In addition, the technical features involved in each specific embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0028] As Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 shown.

[0029] The invention is a one-way self-locking device for a linear drive motor, comprising a friction ring 15 fitted on the tail end 1 of the motor shaft 13 away from the output end 7 of the motor shaft 13 such as a worm, a torsion spring 14 fitted on the friction ring 15, and a fixing base 3 fitted on the torsion spring 14 and fixed to the first end cover 4 of the motor by means of a plurality of screws (not shown in the drawing). It is understood that the central hole of the fixing base 3 is fitted on the torsion spring 14. The first end cover 4 of the motor is screwed (screws and nuts not shown in the drawing) to the motor stator 5 and the second end cover 6 of the motor. The fixing base 3 is also called a mounting base. The torsion spring 14 is generally a multi-coil torsion spring 14. One end of the torsion spring 14, such as the upper end 17 of the torsion spring, is fixed to the fixing base 3, such as being radially limited in the axial groove 2 described below. The above is the prior art.

[0030] The invention point of the invention is:

[0031] As shown in Figure 1 , Figure 2 , Figure 3 , Figure 6 ,

[0032] The other end of the torsion spring 14, such as the lower end 9 of the torsion spring, is fixed to the friction ring 15, such as being inserted into the insertion hole 18 described below. The friction ring 15 is an elastic circular ring composed of a plurality of arc-shaped pieces connected end to end, and the friction ring 15 is in interference fit with the motor shaft 13 to have a pre-tightening friction force. The friction ring 15 and the fixing base 3 have a torsion spring tension structure that when the motor shaft 13 rotates in one direction, such as clockwise, the torsion spring 14 is loosened, and when the motor shaft 13 rotates in the opposite direction, such as counterclockwise, the torsion spring 14 is tightened and the annular compression friction ring 15 to achieve one-way self-locking. The elastic circular ring is also called a circular ring with elasticity. The friction ring 15 can be made of metal materials such as spring steel sheets, or made of plastic materials, or made of nylon materials.

[0033] The torsion spring 14 is preferably gap-fitted on the friction ring 15. Gap-fitting is also called loose-fitting or movable-fitting.

[0034] As shown in Figure 3 , Figure 6 , Figure 7 ,

[0035] The specific structure of the first and last connection is preferably: two single arc-shaped pieces are connected at the top to form an n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a U-shaped concave arc-shaped piece 20, and they are arranged in sequence and continuously until a complete and continuous elastic circular ring is formed. It is not difficult to understand that it can be regarded as the upper half of the shaft as an n-shaped concave arc-shaped piece, and the lower half of the shaft as a U-shaped concave arc-shaped piece. One single concave arc-shaped piece in each n-shaped concave arc-shaped piece in the upper half is connected as a whole with one single concave arc-shaped piece in the U-shaped concave arc-shaped piece in the lower half, and the other single concave arc-shaped piece in the U-shaped concave arc-shaped piece in the lower half is connected as a whole with one single concave arc-shaped piece in the n-shaped concave arc-shaped piece in the upper half. They are connected in sequence and continuously until a complete and continuous elastic circular ring is formed. The n-shaped is also called an arch-shaped. The concave arc-shaped piece is also called a convex arc-shaped piece.

[0036] The n-shaped concave arc-shaped piece 21 is preferably 6-8 pieces, and the U-shaped concave arc-shaped piece 20 is also preferably 6-8 pieces. As shown in Figure 3 , Figure 6 , Figure 7 all of which are 6 pieces: two single arc-shaped pieces are connected at the top to form a first n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a first U-shaped concave arc-shaped piece 20, two single arc-shaped pieces are connected at the top to form a second n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a second U-shaped concave arc-shaped piece 20, two single arc-shaped pieces are connected at the top to form a third n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a third U-shaped concave arc-shaped piece 20, two single arc-shaped pieces are connected at the top to form a fourth n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a fourth U-shaped concave arc-shaped piece 20, two single arc-shaped pieces are connected at the top to form a fifth n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a fifth U-shaped concave arc-shaped piece 20, and two single arc-shaped pieces are connected at the top to form a sixth n-shaped concave arc-shaped piece 21, two single arc-shaped pieces are connected at the bottom to form a sixth U-shaped concave arc-shaped piece 20 (not labeled in the first to sixth drawings, only for convenience of description).

[0037] Of course, as shown in Figure 8 , the specific structure of the first and last connection also allows one of the concave arc-shaped pieces connected at the top to be a whole concave arc-shaped piece 22 without a vertical slot in the middle of the width, and the concave arc-shaped piece does not form an n-shaped. This structure is also within the scope of protection of the present application.

[0038] As shown in Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 ,

[0039] The torsion spring loose structure is preferably that the bottom of the friction ring 15 has a radial protrusion 8, the radial protrusion 8 has a insertion hole 18 for inserting the lower end 9 of the torsion spring, the center hole wall 16 of the fixed seat 3 has an axial recess 2 for accommodating the upper end 17 of the torsion spring, the bottom end of the center hole wall 16 of the fixed seat 3 has an arc-shaped accommodating cavity 12 formed between the first limiting block 11 and the second limiting block 10 for the radial protrusion 8 of the friction ring 15 to rotate within the range of 90°-120°, when the motor shaft 13 rotates to drive the elastic friction ring 15 with pre-tightening force to rotate in one direction, such as clockwise, the torsion spring 14 is loosened and kept by the first limiting block 11, when the motor shaft 13 rotates to drive the elastic friction ring 15 with pre-tightening force to rotate in the opposite direction, such as counterclockwise, the torsion spring 14 is tightened and annularly presses the friction ring 15 and is kept by the second limiting block 10. As shown in Figure 2 、 Figure 4 , the arc-shaped accommodating cavity 12 is approximately the arc-shaped accommodating cavity 12 for the radial protrusion 8 of the friction ring 15 to rotate within the range of 120°. As shown in Figure 4 , the axial recess 2 can axially penetrate the fixed seat 3 to facilitate the installation of the torsion spring 14.

[0040] As shown in Figure 6 、 Figure 7 、 Figure 8 , the lower end opening of the n-shaped concave arc-shaped piece 21 is a horn opening 19. The upper end opening of the U-shaped concave arc-shaped piece 20 is a horn opening 19.

[0041] As shown in Figure 1 、 Figure 2 、 Figure 3 、 Figure 5 , the working process of the present application is approximately as follows:

[0042] When the motor is powered on and the motor shaft 13 rotates in one direction, such as driving the electric lifting table to rise, the motor shaft 13 rotates to drive the elastic friction ring 15 with pre-tightening force to synchronously rotate in one direction, such as clockwise, the torsion spring 14 is loosened, and when the radial protrusion 8 of the friction ring 15 abuts against the first limiting block 11, the torsion spring 14 is kept in the loosened state, the motor normally operates, there is only the pre-warning friction force of the elastic friction ring 15 on the motor shaft 13, which basically does not affect the rotation energy output of the motor shaft 13, the transmission efficiency is large, and the speed is fast.

[0043] When the motor is powered on and the motor shaft 13 rotates in the opposite direction, the motor shaft 13 drives the friction ring 15 to rotate in the opposite direction, such as counterclockwise, and the torsion spring 14 is tightened. When the radial protrusion 8 abuts against the second limiting block 10, the torsion spring 14 is kept in the tightened state and compresses the friction ring 15 in a ring shape to achieve one-way self-locking. However, the motor driving force is greater than the friction force of the self-locking device during the descending process, the transmission efficiency is relatively weak, and the speed is relatively slow, which meets the requirement of slow and stable descending and improves the good mental experience of the customer.

[0044] When the motor stops rotating and the load is too large to brake, such as when the electric lifting table load is too large or the table plate vibrates, the screw in the electric lifting table nut screw pair rotates, driving the worm gear, worm and motor shaft 13 to rotate. The motor shaft 13 drives the friction ring 15 to rotate in the opposite direction, such as counterclockwise, and the torsion spring 14 is tightened. When the radial protrusion 8 abuts against the second limiting block 10, the torsion spring 14 is kept in the tightened state and compresses the friction ring 15 in a ring shape to achieve one-way self-locking. At this time, the friction force between the friction ring 15 compressed by the torsion spring 14 and the motor shaft 13 is greater than the rotating force of the motor shaft 13, so that the table plate is prevented from automatically sinking.

[0045] It is understood that the drawings are only schematic, and if there is any inconsistency between the drawings and the written description, the written description shall prevail.

[0046] The above description is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A one-way self-locking device for a linear drive motor, comprising a friction ring fitted on the tail end of a motor shaft away from the output end of the motor shaft, a torsion spring fitted on the friction ring, and a fixing seat fitted outside the torsion spring and fixedly connected to a first end cover of the motor, one end of the torsion spring being fixedly connected to the fixing seat, characterized in that: The other end of the torsion spring is fixedly connected to the friction ring; the friction ring is an elastic circular ring composed of multiple arc-shaped plates connected end to end. The friction ring is interference-fitted with the motor shaft and has pre-tightened friction force; there is a torsion spring tensioning structure on the friction ring and the fixed seat. The torsion spring tensioning structure is used to relax the torsion spring when the motor shaft rotates in one direction and tighten the torsion spring when it rotates in the opposite direction, and to press the friction ring in a ring to achieve one-way self-locking. The specific structure of the two single-arc pieces is as follows: the tops of the two single-arc pieces are connected to form an n-shaped concave arc piece, and the bottoms of the two single-arc pieces are connected to form a U-shaped concave arc piece. The n-shaped concave arc piece and the U-shaped concave arc piece are arranged alternately and continuously until a complete and continuous elastic circular ring is formed.

2. The one-way self-locking device for a linear drive motor according to claim 1, characterized in that: The torsion spring is fitted onto the friction ring with a gap.

3. The one-way self-locking device for a linear drive motor according to claim 1, characterized in that: The number of concave arc-shaped pieces forming the n-shape is 6-8, and the number of concave arc-shaped pieces forming the U-shape is also 6-8.

4. The one-way self-locking device for a linear drive motor according to claim 1, characterized in that: The lower opening of the n-shaped concave arc-shaped piece is a flared mouth; the upper opening of the U-shaped concave arc-shaped piece is a flared mouth.

5. The one-way self-locking device for a linear drive motor according to claim 1, characterized in that: The torsion spring tensioning structure includes: a radial protrusion at the bottom of the friction ring, with an insertion hole on the radial protrusion for inserting the lower end of the torsion spring; an axial groove on the central hole wall of the fixing seat for accommodating the upper end of the torsion spring; and an arc-shaped cavity formed between two limiting blocks at the bottom of the central hole wall of the fixing seat, allowing the radial protrusion of the friction ring to rotate within a range of 90°-120°. When the motor shaft rotates and drives the elastic friction ring with preload to rotate in one direction, the torsion spring is relaxed and held by the first limiting block. When the motor shaft rotates and drives the elastic friction ring with preload to rotate in the opposite direction, the torsion spring is tightened and compresses the friction ring in a ring shape, held by the second limiting block.

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