Overload protection structure for electric push rod

Abstract

The utility model relates to the technical field of electric push rods, in particular to an overload protection structure for an electric push rod. The overload protection structure for the electric push rod comprises a lead screw and a transmission gear used for being in power connection with a gear reducer, the lead screw sequentially comprises a first threaded section, a fixed section and a second threaded section in the axial direction, the first threaded section, the fixed section and the second threaded section are used for driving the push rod to move along the axis of the push rod, and shaft sleeves are arranged on the outer surfaces of the fixed section and the second threaded section in a sleeved mode. The outer surface of the shaft sleeve is provided with a first retaining shoulder and a second retaining shoulder which are arranged at intervals in the axial direction, the transmission gear is arranged between the first retaining shoulder and the second retaining shoulder in a sleeved mode, and one axial end of the transmission gear is provided with an elastic piece used for abutting against the first retaining shoulder or the second retaining shoulder. The utility model has the advantage that the overall cost of the device is reduced on the premise that the transmission performance and the anti-overload performance of the device are ensured.

Description

TECHNICAL FIELD

[0001] The utility model relates to electric push rod technical field, concretely is overload protection structure for electric push rod. BACKGROUND

[0002] The Chinese patent application with the application number 202220419053.7 discloses an electric push rod with overload protection function, which comprises a motor, a gear reduction box, a top pipe, a guide pipe and a lead screw. The output gear of the gear reduction box is connected with the lead screw through an overload protection structure. The overload protection structure comprises a sleeve fixed to the outside of the lead screw. The output gear shaft has a driving disc fixed to one end. The sleeve outside is fixed with a driven disc. The driving disc and the driven disc are synchronously rotated through an elastic abutting part. The elastic abutting part comprises an abutting disc sleeved on the outside of the sleeve and located on the axial outside of the driven disc, and an elastic piece sleeved on the outside of the sleeve and located on the axial outside of the abutting disc. A plurality of accommodating holes are formed on the driven disc in a circular array with the axis as the center. Each accommodating hole is provided with a spherical ball. The axial outer end of the driving disc close to the driven disc is provided with a plurality of grooves which are spherical and can be matched with the surface of the ball.

[0003] In the above technical solution, the abutting disc is elastically abutted between the ball under the action of the elastic piece, and the other end of the ball is embedded in the groove, and the groove bottom forms an elastic abutment, so that the axial transmission of power is realized through the elastic abutting part between the driving disc and the driven disc, and the transmission torque performance is maintained. However, the structure in the above technical solution is relatively complex. Since the output gear and the lead screw do not need to ensure a large torque to realize transmission, and the working time of the electric push rod in the overload state is short, the abutting disc and the driving disc cannot be worn out. Therefore, the reduction of friction force through the ball will increase the cost of parts, thereby increasing the overall cost of the device. UTILITY MODEL CONTENTS

[0004] The utility model aims at providing an overload protection structure for electric push rod which can reduce the overall cost of the device while ensuring the transmission performance and overload protection performance of the device.

[0005] To achieve the above-mentioned purpose, the utility model discloses an overload protection structure for electric push rod, which comprises a lead screw and a transmission gear connected with a gear reduction box. The lead screw comprises a first threaded section, a fixed section and a second threaded section along the axial direction. The fixed section and the second threaded section are provided with an axle sleeve on the outer surface. The axle sleeve is provided with a first stop shoulder and a second stop shoulder arranged along the axial direction. The transmission gear is arranged between the first stop shoulder and the second stop shoulder. The axial end of the transmission gear is provided with an elastic piece abutting against the first stop shoulder or the second stop shoulder.

[0006] When the electric push rod works, the transmission gear rotates, under the elastic force of the elastic member, the transmission gear drives the shaft sleeve to rotate through the friction force between the axial end face and the first stop shoulder or the second stop shoulder and the friction force between the shaft sleeve outer surface, the shaft sleeve drives the lead screw to rotate at the same time with the transmission gear, when the lead screw is overloaded, the reaction force of the lead screw and the shaft sleeve is greater than the torque of the transmission gear to the shaft sleeve, so that the transmission gear slips between the shaft sleeve under the action of the power device, thereby realizing overload protection.

[0007] Wherein, the elastic member can be any one of the existing elastic members capable of being sleeved on the outer surface of the shaft sleeve and applying axial thrust, such as disc spring, compression spring, etc.

[0008] The utility model discloses a simple structure, reduces the number of parts, thereby reduces the production cost, the utility model discloses have the advantage of reducing the overall cost of device under the premise of guaranteeing the transmission performance and the anti overload performance of device.

[0009] As preferred, the outer surface of the shaft sleeve at one end in the direction away from the transmission gear of the second stop shoulder is provided with a third stop shoulder.

[0010] The third stop shoulder is used for axially limiting the parts between the third stop shoulder and the second stop shoulder to prevent axial movement.

[0011] As preferred, the shaft sleeve comprises a first shaft sleeve composed of the first stop shoulder, the second stop shoulder and the first straight cylinder structure and a second shaft sleeve composed of the third stop shoulder and the second straight cylinder structure, and a bearing is arranged between the third stop shoulder and the second stop shoulder.

[0012] By setting the shaft sleeve as a combination of the first shaft sleeve and the second shaft sleeve, the parts can be assembled between the first stop shoulder, the second stop shoulder and the third stop shoulder.

[0013] As preferred, the elastic member is arranged between the first stop shoulder and the transmission gear, and the first stop shoulder is a locking nut.

[0014] The locking nut is used as the first stop shoulder to realize detachable connection with the first shaft sleeve, and the elastic member can ensure the pre-tightening force of the locking nut to prevent loosening and ensure the transmission performance of the transmission gear.

[0015] As preferred, the inner surface of the first shaft sleeve is provided with an internal thread matched with the second threaded segment.

[0016] The first shaft sleeve is assembled with the second threaded section of the screw rod in a threaded manner, preventing slipping between the shaft sleeve and the screw rod, and further ensuring the transmission performance of the transmission gear.

[0017] As preferred, the first straight cylinder structure comprises a first connecting section and a second connecting section respectively located at the axial two ends of the second shoulder, the first connecting section is used for assembling the transmission gear, and the second connecting section is used for assembling the bearing fixed to the outer surfaces of the second straight cylinder structure and the second connecting section.

[0018] The bearing is axially limited by the second shaft shoulder and the third shaft shoulder on the first shaft sleeve and the second shaft sleeve, preventing the bearing from axially moving.

[0019] As preferred, the first straight cylinder structure further comprises an engaging section located at the end of the first connecting section away from the second shoulder, and the engaging section is used in cooperation with the locking nut.

[0020] The engaging section is arranged on the first straight cylinder structure, so that the locking nut can be assembled at any axial position of the first straight cylinder structure, thereby adjusting the thrust of the elastic member in cooperation with the transmission gear.

[0021] As preferred, a step surface is further arranged between the second connecting section and the second shoulder.

[0022] The step surface arranged between the second connecting section and the second shoulder serves as a clearance, avoiding relative wear between the bearing outer ring and the second shoulder, and ensuring the service life of the bearing outer ring and the first shaft sleeve.

[0023] The utility model discloses a structure only comprising a screw rod, a shaft sleeve, a transmission gear and an elastic member, so that the transmission gear slips between the shaft sleeve under the action of the power device, realizes overload protection under the premise of ensuring the transmission performance of the device, and has the advantages of reducing the overall cost of the device under the premise of ensuring the transmission performance and overload protection performance of the device. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structural schematic view of the utility model.

[0025] Figure 2 It is a three-dimensional sectional structural schematic view of the utility model.

[0026] Figure 3 It is Figure 2 It is an enlarged schematic view of the structure at A in the middle.

[0027] In the figure: 11, lead screw; 111, first threaded section; 112, fixed section; 113, second threaded section; 12, first shaft sleeve; 121, first straight cylinder structure; 1211, first connecting section; 1212, second connecting section; 1213, meshing section; 122, second shoulder; 13, second shaft sleeve; 131, second straight cylinder structure; 132, third shoulder; 14, bearing; 15, transmission gear; 16, disc spring; 17, locking nut. DETAILED DESCRIPTION

[0028] The utility model will be further described below according to the drawings and specific embodiments.

[0029] As shown in the figure, Figure 1 The embodiment discloses an overload protection structure for electric push rod, including lead screw 11 and transmission gear 15 for power connection with gear reduction box, lead screw 11 includes first threaded section 111 for driving push rod to move along its own axis, fixed section 112 and second threaded section 113 along the axial direction in sequence, first threaded section 111 is used for being connected with the top rod in electric push rod Thread, fixed section 112 and second threaded section 113 outer surface are provided with the shaft sleeve, the outer surface of shaft sleeve is provided with the first shoulder and the second shoulder 122 that are arranged at intervals along the axial direction, transmission gear 15 is sleeved between the first shoulder and the second shoulder 122, the axial one end of transmission gear 15 is equipped with the elastic element for being opposite the first shoulder, the first shoulder is locking nut 17, and the elastic element is disc spring 16, and the outer surface one end of shaft sleeve in the direction away from transmission gear 15 of second shoulder 122 is equipped with third shoulder 132.

[0030] As shown in the figure, Figure 2 Shaft sleeve includes first shaft sleeve 12 that is composed of second shoulder 122 and first straight cylinder structure 121 and second shaft sleeve 13 that is composed of third shoulder 132 and second straight cylinder structure 131, the inner surface of first shaft sleeve 12 is equipped with the internal thread matched with second threaded section 113, bearing 14 is arranged between third shoulder 132 and second shoulder 122, and disc spring 16 is arranged between locking nut 17 and transmission gear 15, and the transmission distance of the thrust of disc spring 16 can be reduced by arranging disc spring 16 between locking nut 17 and transmission gear 15, so as to guarantee the application effect of the pre-tightening force of locking nut 17.

[0031] As shown in the figure, Figure 2 , Figure 3As shown, the first straight cylinder structure 121 includes a first connecting section 1211, a second connecting section 1212 and a meshing section 1213 located at the end of the first connecting section 1211 away from the second shoulder 122, respectively. The first connecting section 1211 is used for assembling the transmission gear 15, and the second connecting section 1212 is used for assembling the bearing 14. The bearing 14 is fixed to the outer surface of the second straight cylinder structure 131 and the second connecting section 1212. A stepped surface is further arranged between the second connecting section 1212 and the second shoulder 122. The meshing section 1213 is used in cooperation with the locking nut 17, so that the locking nut 17 can be assembled at any axial position on the first straight cylinder structure 121, thereby adjusting the thrust of the elastic member in cooperation with the transmission gear 15.

[0032] When the electric push rod works, the motor in the electric push rod starts to work. The motor drives the transmission gear 15 to rotate through the transmission gear set. Under the action of the elastic force of the elastic member, the transmission gear 15 drives the first shaft sleeve 12 to rotate through the friction between the axial end face and the locking nut 17 and the friction between the outer surface and the first connecting section 1211. The first shaft sleeve 12 rotates with the transmission gear 15, and at the same time, the lead screw 11 rotates with the first shaft sleeve 12. At this time, the lead screw 11 rotates synchronously with the first shaft sleeve 12 and the second shaft sleeve 13, and is rotationally supported by the bearing 14. When the lead screw 11 is overloaded, the reaction force of the lead screw 11 and the first shaft sleeve 12 is greater than the torque of the transmission gear 15 to the first shaft sleeve 12, so that the transmission gear 15 slips between the outer surface and the first connecting section 1211 under the action of the power device, thereby realizing the overload protection of the motor and preventing the motor from burning out.

Claims

1. An overload protection structure for an electric push rod, comprising a screw rod and a transmission gear for power connection with a gear reduction box, the screw rod comprising, in sequence along an axial direction, a first threaded section for driving the push rod to move along an axis of the push rod, a fixed section, and a second threaded section, characterized in that: The outer surface of the fixed section and the second threaded section is sleeved with a shaft sleeve, the outer surface of the shaft sleeve is provided with a first stop shoulder and a second stop shoulder which are arranged at intervals in the axial direction, the transmission gear is sleeved between the first stop shoulder and the second stop shoulder, and an elastic member for abutting against the first stop shoulder or the second stop shoulder is arranged at one end of the transmission gear in the axial direction.

2. The overload protection structure for an electric trolley according to claim 1, characterized by: A third stop shoulder is arranged at one end of the outer surface of the shaft sleeve in the direction away from the transmission gear.

3. The overload protection structure for an electric trolley according to claim 2, characterized by: The shaft sleeve comprises a first shaft sleeve composed of the first stop shoulder, the second stop shoulder and a first straight cylinder structure, and a second shaft sleeve composed of the third stop shoulder and a second straight cylinder structure, and a bearing is arranged between the third stop shoulder and the second stop shoulder.

4. The overload protection structure for an electric trolley according to claim 2 or 3, characterized in that: The elastic member is arranged between the first stop shoulder and the transmission gear, and the first stop shoulder is a locking nut.

5. The overload protection structure for an electric trolley according to claim 4, characterized by: The inner surface of the first shaft sleeve is provided with an internal thread matched with the second threaded section.

6. The overload protection structure for an electric trolley according to claim 5, characterized by: The first straight cylinder structure comprises a first connecting section and a second connecting section which are respectively arranged at the two ends of the second stop shoulder in the axial direction, the first connecting section is used for assembling the transmission gear, the second connecting section is used for assembling the bearing, and the bearing is fixed to the outer surfaces of the second straight cylinder structure and the second connecting section.

7. The overload protection structure for an electric trolley according to claim 6, characterized by: The first straight cylinder structure further comprises an engaging section arranged at one end of the first connecting section away from the second stop shoulder, and the engaging section is used in cooperation with the locking nut.

8. The overload protection structure for an electric trolley according to claim 6, characterized by: A stepped surface is further arranged between the second connecting section and the second stop shoulder.

Images