Low-noise electric push rod

Abstract

The invention relates to the technical field of electric push rods, in particular to a low-noise electric push rod. The low-noise electric push rod comprises an end cover and a bottom shell which are assembled with each other, a transmission cavity is formed between the end cover and the bottom shell, a gear transmission assembly is arranged in the transmission cavity, the gear transmission assembly is in power connection with a lead screw arranged in the axial direction of the end cover, a top pipe is arranged on the lead screw, and the top pipe is in power connection with the end cover. The lead screw comprises a first threaded section, an assembling section and a second threaded section which are sequentially arranged in the axial direction, the first threaded section is used for being in threaded fit with a jacking pipe, the assembling section is provided with a supporting assembly, and the second threaded section is sleeved with a driven gear used for being matched with the gear transmission assembly. The second threaded section is provided with a first bearing and a second bearing which are distributed on the two axial sides of the driven gear. The motor-driven push rod has the advantage that the overall operation stability and the mute performance of the motor-driven push rod can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of electric push rods, in particular to a low-noise electric push rod. Background Art

[0002] A Chinese patent application with application number 201510287672.X discloses a driving motor series driving gear structure, including a driving motor, a fixing bolt, a driving gear, a spline sleeve and a trailer body. The lower end of the driving motor is provided with a convex portion for connecting the driving gear, and the trailer body is provided with a boss, and the boss is provided with a bearing. The bearing is fixedly connected to the boss through a retaining ring. The bearing includes an upper bearing and a lower bearing. The inner ring sleeve of the upper bearing and the inner ring sleeve of the lower bearing are arranged opposite to each other up and down. The retaining ring is located in the outer ring groove of the spline sleeve and is clamped on the surface of the lower bearing away from the upper bearing, and the spline sleeve is axially positioned by the plane of the boss contacted by the upper bearing and the retaining ring.

[0003] In the above technical scheme, the axial positioning of the spline sleeve is achieved by the friction force between the inner rings of two bearings symmetrically arranged along the axial direction of the boss and the surface of the spline sleeve, and the spline sleeve is axially positioned in a single direction by a retaining ring, thereby ensuring the power transmission of the driving gear. However, the above technical scheme only realizes the radial support of the power output shaft of the driving motor by the trailer body using two relatively arranged bearings. Since the two bearings are both mounted on the outer surface of the spline sleeve, under the influence of the inevitable form and position tolerances between the bearings and the spline sleeve, between the trailer body and the bearings, and between the driving motor and the power output shaft of the driving motor, when the power output shaft of the driving motor rotates and swings in the circumferential direction during rotation, the two bearings cannot directly clamp the spline sleeve to axially position the spline sleeve, resulting in the power output shaft of the driving motor being affected by the rotation and swinging during operation, resulting in noise.

[0004] However, the above technical problems also exist in other motor drive systems, such as the lead screw and gear transmission assembly in the electric push rod, which are also affected by the vibration caused by the rotation and swing of the lead screw. When the rotation and swing of the lead screw are fed back to the gear transmission assembly, the noise generated by the gear transmission assembly increases. Summary of the invention

[0005] The object of the present invention is to provide an electric push rod which can reduce the vibration effect caused by the rotation and swing of a screw rod, so as to reduce the noise generated by a gear transmission component.

[0006] To achieve the above-mentioned purpose, the present invention discloses a low-noise electric push rod, comprising an end cover and a bottom shell assembled with each other, a transmission cavity is formed between the end cover and the bottom shell, a gear transmission assembly is arranged in the transmission cavity, the gear transmission assembly is dynamically connected to a screw rod arranged along the axial direction of the end cover, a top pipe is arranged on the screw rod, the screw rod comprises a first threaded section, an assembly section and a second threaded section arranged in sequence along the axial direction, the first threaded section is used to cooperate with the top pipe thread, the assembly section is provided with a support assembly, the second threaded section is sleeved with a driven gear for cooperating with the gear transmission assembly, the second threaded section is provided with a first bearing and a second bearing distributed on both sides of the axial direction of the driven gear, the first bearing and the second bearing clamp the driven gear along the axial direction of the screw rod.

[0007] When the electric push rod is working, the gear transmission assembly drives the driven gear to rotate, which in turn drives the lead screw to rotate. The lead screw makes the top pipe reciprocate along a straight line through the first threaded section. Due to the shape and position tolerance, the lead screw will rotate and swing in the circumferential direction when it rotates. The rotation and swing of the lead screw in the circumferential direction makes the driven gear swing along the axis direction of the lead screw. The first bearing and the second bearing limit the driven gear along the axial direction of the lead screw, so that the swing amplitude of the driven gear is reduced.

[0008] The present invention arranges a first bearing and a second bearing on the second threaded section of the screw rod, and clamps the driven gear along the axial direction of the screw rod by the first bearing and the second bearing, thereby limiting the impact of the bouncing of the driven gear caused by the rotation and swing of the screw rod, thereby limiting the swing amplitude of the screw rod in the circumferential direction by the driven gear, reducing the noise generated by the gear transmission component due to the rotation and swing of the screw rod, and the present invention has the advantage of improving the overall running stability and quietness of the electric push rod.

[0009] Preferably, the support assembly includes a sleeve, a third bearing sleeved on the sleeve and a fixing seat for fixing the third bearing, the fixing seat is fixed in the transmission cavity on the inner side of the end cover, a stop portion is provided on the sleeve along the axis direction of the screw rod, a locking nut sleeved on the first threaded segment is provided on one side of the sleeve symmetrical to the stop portion, and the third bearing is located between the locking nut and the stop portion.

[0010] The third bearing is assembled with the assembly section of the screw rod through the shaft sleeve. When the gear transmission assembly drives the screw rod to rotate, the third bearing limits the axial position of the screw rod through the shaft sleeve and supports the radial position of the screw rod.

[0011] Among them, the locking nut and the second thread segment are threadedly matched, and the first thread segment and the second thread segment are designed with positive and negative threads, thereby preventing the locking nut from loosening during the process of the first thread segment driving the top pipe to move.

[0012] Preferably, the fixing seat comprises a large diameter section, a small diameter section and a transition section connected between the large diameter section and the small diameter section, the large diameter section is used to cooperate with the third bearing, the small diameter section is provided with a first mounting groove at one end away from the large diameter section, and the outer ring of the second bearing cooperates with the first mounting groove.

[0013] Compared with a straight cylindrical fixing seat, it can cooperate with the second bearing with a size that is more closely matched to the second bearing, thereby utilizing a second bearing with a smaller diameter to limit the driven gear and saving the cost of the bearings used; compared with a fixing seat with a large diameter section and a small diameter section formed by a thin upper wall and a thick lower wall, the fixing seat in this solution is more convenient for die casting.

[0014] Preferably, the small diameter section is provided with a lateral opening to make way for the gear transmission assembly.

[0015] By providing a lateral opening on the small diameter section, the opening is used as a clearance space for the gear transmission assembly, thereby shortening the distance between the lead screw and the power shaft of the gear transmission assembly, thereby reducing the diameter of the driven gear.

[0016] Preferably, the driven gear includes a sleeve portion for assembling with the second threaded segment and a gear portion arranged on the outer circumferential surface of the sleeve portion, the gear portion is provided with a groove opening toward the fixed seat, and the sleeve portion is symmetrically provided with a second mounting groove and a third mounting groove at both axial ends, the inner ring of the second bearing cooperates with the second mounting groove, and the inner ring of the first bearing cooperates with the third mounting groove.

[0017] The first bearing and the second bearing are respectively fixed on the sleeve portion of the driven gear. Compared with the method of directly installing the first bearing and the second bearing on the second threaded segment, the axial length required for the screw rod to be assembled can be saved, thereby reducing the vibration effect caused by the rotation and swing of the screw rod.

[0018] Preferably, the bottom width of the second mounting groove matches the radial width of the second bearing inner ring, and the bottom width of the third mounting groove matches the radial width of the first bearing inner ring, so as to prevent the bottom of the second mounting groove or the bottom of the third mounting groove from sliding relative to the outer ring of the bearing, causing wear on the gear portion of the driven gear and the outer ring of the bearing, and generating noise between the driven gear and the outer ring of the bearing.

[0019] Preferably, an annular convex strip is provided on the bottom shell, and the outer circle of the first bearing cooperates with the inner wall of the annular convex strip. By setting the annular convex strip inside the bottom shell, the back side of the driven gear relative to the second bearing can be limited by a third bearing with the same specifications as the second bearing.

[0020] Preferably, a positioning pin is provided at one axial end of the large diameter portion away from the small diameter section, and the positioning pin facilitates positioning when the fixing seat is assembled with the end cover surface.

[0021] Preferably, two positioning pins are provided and are symmetrically arranged with the axis of the fixing seat as the center, which further facilitates the correction and positioning during the assembly process of the positioning pin, the fixing seat and the end cover surface.

[0022] Preferably, the second thread segment is a double-plane shaft structure, and the second thread segment cooperates with the driven gear through a plane.

[0023] Compared with the method of opening a keyway at the second thread segment and connecting the driven gear through a key, it is sufficient to directly machine a plane at the second thread segment, thereby reducing the machining cost and thus reducing the overall cost of the device.

[0024] The present invention clamps the driven gear along the axial direction of the screw rod by the first bearing and the second bearing, thereby limiting the vibration of the driven gear caused by the rotation and swing of the screw rod, and has the advantage of improving the overall running stability and quietness of the electric push rod. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A structural schematic diagram of the present invention.

[0026] Figure 2 It is a schematic diagram of the explosion structure of the present invention.

[0027] Figure 3 It is a schematic diagram of the cross-sectional structure of the present invention.

[0028] Figure 4 for Figure 3 A schematic diagram of the enlarged structure at point A in the middle.

[0029] Figure 5 It is a structural schematic diagram of the fixing seat of the present invention.

[0030] Figure 6 It is a schematic structural diagram of the second thread segment of the present invention.

[0031] In the figure: 11, end cover; 12, bottom shell; 121, annular convex strip; 13, gear transmission assembly; 14, screw rod; 141, first threaded section; 142, assembly section; 143, second threaded section; 1431, double-plane shaft structure; 15, driven gear; 151, groove; 152, sleeve section; 153, gear section; 16, fixed seat; 161, large diameter section; 162, small diameter section; 163, transition section; 164, first mounting groove; 165, lateral opening; 166, positioning pin; 17, third bearing; 18, bushing; 19, locking nut; 20, second bearing; 21, first bearing. DETAILED DESCRIPTION

[0032] The present invention will be further described below based on the accompanying drawings and specific embodiments.

[0033] Depend on Figure 1 As shown, this embodiment discloses a low-noise electric push rod, including an end cover 11 and a bottom shell 12 assembled with each other, a transmission cavity is formed between the end cover 11 and the bottom shell 12, Figure 3 As shown, a gear transmission assembly 13 is provided in the transmission cavity, and the gear transmission assembly 13 is connected to a screw rod 14 arranged along the axial direction of the end cover 11. A top pipe is provided on the screw rod 14. Figure 4 As shown, the screw rod 14 includes a first threaded segment 141, an assembly segment 142 and a second threaded segment 143 arranged in sequence along the axial direction. The first threaded segment 141 is used to cooperate with the top pipe thread. The assembly segment 142 is provided with a support assembly. The second threaded segment 143 is sleeved with a driven gear 15 for cooperating with the gear transmission assembly 13. The second threaded segment 143 is provided with a first bearing 21 and a second bearing 20 distributed on both axial sides of the driven gear 15. The first bearing 21 and the second bearing 20 clamp the driven gear 15 along the axial direction of the screw rod 14. The driven gear 15 includes a sleeve portion 152 for assembling with the second threaded section 143 and a gear portion 153 provided on the outer circumferential surface of the sleeve portion 152. The gear portion 153 is provided with a groove 151 with an opening toward the fixed seat 16. The sleeve portion 152 is symmetrically provided with a second mounting groove and a third mounting groove at both axial ends. The groove bottom width of the second mounting groove matches the radial width of the inner ring of the second bearing 20, and the groove bottom width of the third mounting groove matches the radial width of the inner ring of the first bearing 21. Figure 2 As shown, an annular convex strip 121 is provided on the bottom shell 12 , and the outer circle of the first bearing 21 matches with the inner wall of the annular convex strip 121 .

[0034] The supporting assembly includes a sleeve 18, a third bearing 17 sleeved on the sleeve 18 and a fixing seat 16 for fixing the third bearing 17. The fixing seat 16 is fixed in the transmission cavity on the inner side of the end cover 11. A stopper is provided on the sleeve 18 along the axial direction of the screw rod 14. A locking nut 19 sleeved on the first threaded segment 141 is provided on one side of the sleeve 18 symmetrical to the stopper. The third bearing 17 is located between the locking nut 19 and the stopper.

[0035] Depend on Figure 5As shown, the fixing seat 16 includes a large diameter section 161, a small diameter section 162 and a transition section 163 connected between the large diameter section 161 and the small diameter section 162. The large diameter section 161 is used to cooperate with the third bearing 17. Two positioning pins are provided at the axial end of the large diameter portion away from the small diameter section 162. The positioning pins are symmetrically arranged with the axis of the fixing seat 16 as the center. A first mounting groove 164 is provided at the end of the small diameter section 162 away from the large diameter section 161. The outer ring of the second bearing 20 cooperates with the first mounting groove 164. A lateral opening 165 is provided on the small diameter section 162 to make way for the gear transmission assembly 13.

[0036] Depend on Figure 6 As shown, the second thread segment 143 is a double-plane shaft structure 1431 , and the second thread segment 143 cooperates with the driven gear 15 through a plane.

[0037] There is a clearance fit between the inner ring of the third bearing 17 and the sleeve 18, and between the outer ring of the third bearing 17 and the large diameter section 161 of the fixed seat 16. There is a clearance fit between the inner ring of the second bearing 20 and the second mounting groove, and between the outer ring of the second bearing 20 and the small diameter section 162 of the fixed seat 16. There is a clearance fit between the inner ring of the first bearing 21 and the third mounting groove, and between the outer ring of the first bearing 21 and the annular convex strip 121. The first bearing 21, the second bearing 20 and the third bearing 17 are all clearance fits with a single-side clearance of less than 0.01 mm.

[0038] When the electric push rod is working, the driven gear 15 in the gear transmission assembly 13 is driven to rotate, and the driven gear 15 drives the screw rod 14 to rotate through the double-plane shaft structure 1431. The screw rod 14 rotates relative to the screw rod 14 nut in the prior art through the first threaded section 141, and then the top pipe is moved back and forth in a straight line through the thread of the first threaded section 141. Due to the shape and position tolerance, the screw rod 14 will rotate and swing in the circumferential direction when it rotates. The screw rod 14 rotates and swings in the circumferential direction, and the jumping effect of the screw rod 14 causes the driven gear 15 to swing up and down along the axis of the screw rod 14, and due to the assembly gap between the driven gear 15 and the second threaded section 143 of the screw rod 14, its swing amplitude is larger than that of the screw rod 14. At this time, the first bearing 21 in the annular convex strip 121 and the second bearing 20 on the small diameter section 162 limit the driven gear 15 along the axial direction of the screw rod 14, so that the driven gear 15 reduces the swing amplitude and reduces the noise generated by the meshing of the gear transmission assembly 13.

Claims

1. A low-noise electric push rod, comprising an end cover and a bottom shell assembled with each other, a transmission cavity is formed between the end cover and the bottom shell, a gear transmission assembly is arranged in the transmission cavity, the gear transmission assembly is dynamically connected to a screw rod arranged along the axial direction of the end cover, a top tube is arranged on the screw rod, and the characteristics are: The screw rod includes a first threaded section, an assembly section and a second threaded section arranged in sequence along the axial direction, the first threaded section is used to cooperate with the top pipe thread, the assembly section is provided with a support assembly, the second threaded section is sleeved with a driven gear for cooperating with the gear transmission assembly, the second threaded section is provided with a first bearing and a second bearing distributed on both sides of the axial direction of the driven gear, the first bearing and the second bearing clamp the driven gear along the axial direction of the screw rod.

2. A low-noise electric linear actuator according to claim 1, characterized in that: The support assembly includes a sleeve, a third bearing sleeved on the sleeve and a fixing seat for fixing the third bearing, the fixing seat is fixed in the transmission cavity on the inner side of the end cover, a stop portion is provided on the sleeve along the axis direction of the screw rod, a locking nut sleeved on the first threaded segment is provided on one side of the sleeve symmetrical to the stop portion, and the third bearing is located between the locking nut and the stop portion.

3. A low-noise electric linear actuator according to claim 2, characterized in that: The fixing seat includes a large diameter section, a small diameter section and a transition section connected between the large diameter section and the small diameter section. The large diameter section is used to cooperate with the third bearing. The small diameter section is provided with a first mounting groove at one end away from the large diameter section, and the outer ring of the second bearing cooperates with the first mounting groove.

4. The low-noise electric linear actuator according to claim 3, characterized in that: The small diameter section is provided with a lateral opening for making way for the gear transmission assembly.

5. A low-noise electric linear actuator according to claim 2, 3 or 4, characterized in that: The driven gear includes a sleeve portion for assembling with the second threaded section and a gear portion arranged on the outer circumferential surface of the sleeve portion, the gear portion is provided with a groove opening toward the fixed seat, and a second mounting groove and a third mounting groove are symmetrically provided at two axial ends of the sleeve portion, the inner ring of the second bearing cooperates with the second mounting groove, and the inner ring of the first bearing cooperates with the third mounting groove.

6. The low-noise electric linear actuator according to claim 5, characterized in that: The groove bottom width of the second mounting groove matches the radial width of the second bearing inner ring, and the groove bottom width of the third mounting groove matches the radial width of the first bearing inner ring.

7. The low-noise electric linear actuator according to claim 1, characterized in that: The bottom shell is provided with an annular convex strip, and the outer circle of the first bearing matches with the inner wall of the annular convex strip.

8. The low-noise electric linear actuator according to claim 3, characterized in that: A positioning pin is provided at one axial end of the large diameter portion away from the small diameter section.

9. The low-noise electric linear actuator according to claim 8, characterized in that: The positioning pins are provided with two and are symmetrically arranged with the axis of the fixing seat as the center.

10. The low-noise electric linear actuator according to claim 1, characterized in that: The second thread segment is a double-plane shaft structure, and the second thread segment cooperates with the driven gear through a plane.

Images