An electric push rod

Abstract

The utility model particularly relates to an electric push rod. An electric push rod comprises a housing, a screw rod, a screw nut, a jack pipe and a guide tube, and a driver. A micro switch assembly is arranged between the screw nut and the driver. The micro switch assembly comprises a circuit board and a first micro switch and a second micro switch both fixed on the same axial side of the circuit board. The screw nut is provided with a first triggering member for triggering the first micro switch. A radially movable elastic moving member is arranged between the second micro switch and the screw nut. The elastic moving member is matched with a pull rod. One axial end of the pull rod is provided with a second triggering member that contacts and cooperates with the elastic moving member. The second triggering member has an overlapping portion with the first micro switch and the second micro switch in the radial direction. The other axial end of the pull rod is provided with a protrusion for linkage with the screw nut. The utility model has the advantage of being able to reduce the axial base installation distance of a linear electric push rod.

Description

Technical Field

[0001] The utility model particularly relates to an electric push rod. Background Art

[0002] The Chinese patent application number 201310689341.X discloses a linear electric push rod with a micro switch limiter, including a linear electric push rod assembly and a micro switch limiter that can control the stroke of the electric push rod. The micro switch limiter includes a circuit board and an upper limit micro switch and a lower limit micro switch located on both sides of the circuit board. The lower limit micro switch is triggered after the lead screw nut of the electric push rod moves downward to the limit position; the upper limit micro switch is equipped with a flat pull rod, and a boss is provided at the end of the flat pull rod. When the lead screw nut of the electric push rod moves upward to the boss, the flat pull rod will be pulled, so that the upper limit micro switch is triggered.

[0003] In the above solution, the upper limit micro switch and the lower limit micro switch are located on both axial sides of the circuit board, which will increase the axial length of the entire linear electric push rod and waste the basic installation distance of the linear push rod as a whole. Utility Model Content

[0004] The utility model aims to provide an electric push rod which can reduce the axial base installation distance of a linear electric push rod.

[0005] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: an electric push rod, comprising a shell, a screw, a screw nut, a jacking tube and a guide tube, a driver for driving the screw to rotate is arranged in the shell, a micro switch assembly is arranged between the screw nut and the driver, the micro switch assembly comprises a circuit board, a first micro switch and a second micro switch, the first micro switch and the second micro switch are both fixed on the same axial side of the circuit board, a first triggering member for triggering the first micro switch is arranged at one end of the screw nut facing the circuit board; a radially movable elastic moving member is arranged between the second micro switch and the screw nut, the elastic moving member is matched with a pull rod, a second triggering member contacting and cooperating with the elastic moving member is arranged at one axial end of the pull rod, the second triggering member has an overlapping portion in the radial direction with the first micro switch and the second micro switch, and a protrusion for linkage with the screw nut is arranged at the other axial end of the pull rod; when the pull rod is pulled by the screw nut, the second triggering member moves axially to make the elastic moving member move radially and trigger the second micro switch.

[0006] When this solution is in use, the driver drives the screw to rotate, and the rotation of the screw drives the axial movement of the screw nut. The top tube is fixedly connected to the screw nut, and the top tube will perform telescopic movement. When the screw nut moves downward to the limit position, the first trigger of the screw nut will contact the trigger point of the first micro switch, so that the driver will no longer drive the screw nut to continue to move downward. When the screw nut moves upward to the limit position, the screw nut will contact the protrusion, so that the pull rod is pulled by the screw nut and moves upward together with the screw nut. The pulling of the pull rod causes the second trigger to also move upward (axially), squeeze the elastic moving part, and the elastic moving part moves radially, thereby contacting the trigger point of the second micro switch, so that the driver no longer drives the screw nut to continue to move upward. After the driver rotates in the opposite direction, the screw nut is reset, the second trigger reduces the squeezing of the elastic moving part, and the elastic moving part is reset, so that it does not contact the second micro switch.

[0007] The fixing method among the housing, the screw rod, the screw nut, the jack pipe and the guide tube is the fixing method of the housing, the screw rod, the screw nut, the jack pipe and the guide tube of any existing linear electric push rod. The first micro switch and the second micro switch are any existing micro switches that can be used to control the stroke of the electric push rod. How the upward movement (axial movement) of the second trigger member causes the elastic movable member to move radially, the second trigger member can be set in a spherical shape or a disc shape, when the second trigger member moves axially, it can squeeze the elastic movable member, or the second trigger member and the elastic movable member can be in inclined contact, and the movement of the second trigger member can also squeeze the elastic movable member, so that the elastic movable member moves radially.

[0008] In this solution, the first micro switch and the second micro switch are all arranged on the same side of the circuit board, thereby reducing the axial space occupied by the entire micro switch assembly, thereby optimizing the axial base installation distance of the linear push rod and making the entire linear push rod shorter.

[0009] Preferably, the contact surface between the elastic moving member and the second triggering member is an inclined surface.

[0010] The second triggering member and the elastic moving member are both provided with inclined surfaces, and the movement of the elastic moving member is achieved through the contact and cooperation between the inclined surfaces, so that the axial distance can be reduced.

[0011] Preferably, the elastic movable part is arranged on a first fixed plate, the first fixed plate is fixedly connected to the shell, the first fixed plate is provided with a slide groove cooperating with the elastic movable part, the elastic movable part includes an elastic part and a movable part, the elastic part is radially arranged and the two ends are respectively in contact with the groove wall of the slide groove and the movable part, the movable part is slidably matched with the slide groove, and the slide groove limits the axial position of the movable part.

[0012] The axial position of the moving member is limited by the sliding groove, so that the moving member will not deviate when being squeezed by the second triggering member. Wherein, the first fixing plate is fixedly connected to the housing directly or indirectly.

[0013] Preferably, the second micro switch comprises a housing, a contact and a paddle for triggering the contact, one end of the paddle is rotatably connected to the housing, and the moving member is located on the axial side of the rotationally connected end of the paddle and the housing.

[0014] The moving part is arranged on the axial side of the rotating connection end between the paddle and the housing, so that a slight radial movement of the moving part can realize a relatively large swing of the paddle, thereby triggering the contact, and the axial space occupied by the entire moving part can be reduced.

[0015] Preferably, the circuit board is provided with an axially penetrating guide hole, the second trigger member is provided with a guide section extending into the clearance hole, the guide section is slidably matched with the guide hole, and the guide hole can limit the circumferential rotation of the guide section.

[0016] The guide section can prevent the second triggering member from being offset, thereby ensuring that the position of the second triggering member moves axially.

[0017] Preferably, the guide section is provided with an axially extending internal threaded hole, and the end of the pull rod connected to the second trigger member is provided with an external threaded structure threadably matched with the internal threaded hole.

[0018] The guide section has an axial length, and the internal threaded hole is arranged in the guide section to ensure that the internal threaded hole has a certain axial length, so that the pull rod will not be loose after the threaded engagement with the second trigger member. At the same time, the pull rod can be replaced with the second trigger member, and pull rods of different lengths can make the electric push rod have different strokes.

[0019] Preferably, the circuit board is fixed on a second fixing plate, the first fixing plate and the second fixing plate are spaced apart in the axial direction and the micro switch assembly is arranged therebetween.

[0020] The micro switch assembly is fixed by providing a second fixing plate.

[0021] Preferably, the screw nut is provided with an axially penetrating clearance hole, and the pull rod passes through the clearance hole and is slidably engaged with the clearance hole.

[0022] The clearance hole can limit the pull rod in radial direction. Compared with the flat pull rod in the prior art in the background technology, the pull rod of this solution can be set in a cylindrical shape, which has higher strength.

[0023] The utility model has the advantage of being able to reduce the axial installation distance of the linear electric push rod. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0025] Figure 2 for Figure 1 sectional view of .

[0026] Figure 3 for Figure 2 Enlarged view of point A after removing the screw rod.

[0027] Figure 4 This is a cross-sectional view of the micro switch assembly after the screw rod is removed.

[0028] Figure 5 This is a cross-sectional view of the micro switch assembly after removing the screw rod, guide tube and housing.

[0029] Figure 6 This is a schematic diagram of the structure of the micro switch assembly after the screw rod is removed.

[0030] Figure 7 It is a schematic diagram of the structure at the elastic moving part.

[0031] Figure 8 It is a schematic diagram of the structure at the elastic moving part.

[0032] Figure numbers: 1. shell; 11. guide tube; 12. jacking tube; 13. screw; 14. screw nut; 15. driver; 16. reducer; 17. bearing; 18. rotating block; 2. first micro switch; 21. first trigger member; 3. second micro switch; 31. second trigger member; 311. pull rod; 312. protrusion; 32. elastic moving member; 321. elastic member; 322. moving member; 33. guide section; 331. internal threaded hole; 41. first fixed plate; 411. connecting column; 412. matching part; 42. second fixed plate; 43. third fixed plate; 44. locking hole; 5. circuit board; 6. paddle; 7. contact. DETAILED DESCRIPTION

[0033] The utility model is further described below based on the accompanying drawings and specific embodiments.

[0034] like Figure 1 , Figure 2 and Figure 3As shown, this embodiment discloses an electric push rod, including a housing 1, a guide tube 11, a top tube 12, a screw 13, and a screw nut 14. A driver 15 is provided in the housing 1. The driver 15 is a motor. The output end of the driver 15 is connected to a reducer 16. The output end of the reducer 16 is connected to the screw 13 and drives the screw 13 to rotate. The guide tube 11 and the housing 1 are threadedly matched. The screw nut 14 is located in the top tube 12. A plurality of annular evenly spaced outer protrusions are provided on the circumferential outer wall of the screw nut 14. A plurality of annular evenly spaced grooves extending in the axial direction are provided on the hole wall of the top tube 12. The outer protrusions and the grooves are slidably matched to limit the circumferential rotation of the screw nut 14. A rotating block 18 is threadedly matched on the circumferential outer side of the screw 13. The rotating block 18 is rotatably connected to the housing 1 through a bearing 17. The rotating block 18 is located on the axial side of the reducer 16. The rotating block 18 supports the screw 13 in the radial direction.

[0035] like Figure 2 , Figure 5 and Figure 6 As shown, a micro switch assembly is provided between the screw nut 14 and the reducer 16, and the micro switch assembly includes a circuit board 5, a first micro switch 2 and a second micro switch 3 fixed on the circuit board 5 and located on the same axial side of the circuit board 5, and a first fixing plate 41, a second fixing plate 42 and a third fixing plate 43 arranged at intervals in the axial direction. The circuit board 5, the first fixing plate 41, the second fixing plate 42 and the third fixing plate 43 are all provided with a through hole that axially penetrates and makes way for the screw. The threaded fit between the conduit 11 and the housing 1 enables the third fixing plate 43 to be fixed between the axial end of the conduit 11 and the rotating block 18; the first fixing plate 41 is provided with a connecting column 411 extending axially toward the second fixing plate 42 side, and the connecting column 411 can press the circuit board 5 so that the circuit board 5 is supported on the second fixing plate 42. A locking hole 44 is provided between the connecting column 411 , the second fixing plate 42 and the third fixing plate 43 , and a screw (not shown) passes through the locking hole 44 to fix the circuit board 5 , the first fixing plate 41 , the second fixing plate 42 and the third fixing plate 43 .

[0036] like Figure 3 and Figure 6 As shown, the first micro switch 2 and the second micro switch 3 are located between the first fixing plate 41 and the circuit board 5, the lead screw nut 14 is provided with a first trigger member 21 extending axially toward the first fixing plate 41, and the first fixing plate 41 is provided with a notch axially penetrating therethrough to make way for the first trigger member 21. When the lead screw nut 14 descends to the extreme position, the first trigger member 21 squeezes the paddle 6 of the first micro switch 2 to trigger the first micro switch 2.

[0037] like Figure 4 , Figure 6 , Figure 7 and Figure 8 As shown, the first fixed plate 41 is provided with a radially extending matching portion 412 on the axial side facing the circuit board 5, and the matching portion 412 is provided with a radially extending sliding groove (not shown in the figure). An elastic moving member 32 is slidably arranged in the sliding groove, and the elastic moving member 32 includes an elastic member 321 and a moving member 322 fixed to the elastic member 321, and the elastic member 321 is a compression spring; the opposite sides of the moving member 322 are provided with a notch (not shown in the figure) that opens to the outside and extends in the radial direction, and the matching portion 412 extends into the notch to limit the axial position of the moving member 322. The elastic moving member 32 is matched with a second trigger member 31, and the second trigger member 31 and the moving member 322 are in contact and matched, and the contacting surfaces of the two are both inclined surfaces. The second trigger member 31 is provided with an axially extending guide section 33, and the circuit board 5 is provided with a guide hole (not shown in the figure) that is axially opened and slidably matched with the guide section 33, and the cross-sectional shape of the circumferential outer edge of the guide section 33 and the circumferential inner edge of the guide hole are both rectangular to limit the circumferential rotation of the guide section 33. The guide section 33 is provided with an axially extending internal threaded hole 331, one end of the pull rod 311 is provided with an external threaded structure and threadedly matched with the internal threaded hole 331; the other end of the pull rod 311 is provided with a radially extending protrusion 312. The screw nut 14 and the first fixing plate 41 are both provided with an axially penetrating clearance hole, the pull rod 311 passes through the clearance hole and slides with the clearance hole, wherein the size of the protrusion 312 is larger than the aperture of the clearance hole. The first micro switch 2 and the second micro switch 3 both include a housing, a paddle 6 and a contact 7, one end of the paddle 6 is rotatably connected to the housing, and the moving member 322 is located on the axial side of the rotating end of the paddle 6 and the housing. When the screw nut goes up to the limit position, the pull rod 311 is pulled by the screw nut 14, and the second trigger member 31 moves axially to squeeze the moving member 322, so that the moving member 322 squeezes the paddle 6, and the paddle 6 squeezes the contact 7 to trigger the second micro switch 3.

[0038] The first micro switch 2 and the second micro switch 3 completely overlap in the radial direction; the second trigger member 31 is arranged to overlap with the second micro switch 3 and the first micro switch 2 in the radial direction.

[0039] In actual use, when the screw 13 is driven, the screw nut 14 moves downward, and the first trigger member 21 contacts and cooperates with the paddle 6 of the first micro switch 2, thereby triggering the first micro switch 2, so that the driver 15 stops driving the screw 13 to rotate. When the driver 15 drives the screw 13 to rotate in the opposite direction, the screw nut 14 moves upward, and the screw nut 14 contacts the protrusion 312 of the pull rod 311, and the pull rod 311 is pulled axially, and the second trigger member 31 moves axially to squeeze the moving member 322, and the moving member 322 moves radially to squeeze the paddle 6 of the second micro switch 3, thereby triggering the second micro switch 3, so that the driver 15 stops driving the screw 13 to rotate.

Claims

1. An electric push rod, comprising a housing, a screw rod, a screw rod nut, a jacking tube and a guide tube, wherein a driver for driving the screw rod to rotate is arranged in the housing, and a micro switch assembly is arranged between the screw rod nut and the driver, characterized in that: The microswitch assembly includes a circuit board, a first microswitch and a second microswitch, the first microswitch and the second microswitch are both fixed on the same axial side of the circuit board, and a first triggering member for triggering the first microswitch is provided at one end of the lead screw nut facing the circuit board; a radially movable elastic moving member is provided between the second microswitch and the lead screw nut, and the elastic moving member is matched with a pull rod, and a second triggering member contacting and cooperating with the elastic moving member is provided at one axial end of the pull rod, and the second triggering member has an overlapping portion in the radial direction with the first microswitch and the second microswitch, and a protrusion for linkage with the lead screw nut is provided at the other axial end of the pull rod; when the pull rod is pulled by the lead screw nut, the second triggering member moves axially to make the elastic moving member move radially and trigger the second microswitch.

2. The electric linear actuator according to claim 1, characterized in that: The contact surface between the elastic moving member and the second triggering member is an inclined surface.

3. The electric linear actuator according to claim 1, characterized in that: The elastic movable member is arranged on a first fixed plate, the first fixed plate is fixedly connected to the shell, the first fixed plate is provided with a slide groove cooperating with the elastic movable member, the elastic movable member includes an elastic member and a movable member, the elastic member is radially arranged and the two ends are respectively in contact with the groove wall of the slide groove and the movable member, the movable member is slidably matched with the slide groove, and the slide groove limits the axial position of the movable member.

4. The electric linear actuator according to claim 3, characterized in that: The second micro switch comprises a housing, a contact and a paddle for triggering the contact, one end of the paddle is rotatably connected to the housing, and the moving member is located on the axial side of the rotatably connected end of the paddle and the housing.

5. The electric linear actuator according to any one of claims 1 to 4, characterized in that: The circuit board is provided with an axially penetrating guide hole, and the second trigger member is provided with a guide section extending into the clearance hole. The guide section is slidably matched with the guide hole, and the guide hole can limit the circumferential rotation of the guide section.

6. The electric linear actuator according to claim 5, characterized in that: The guide section is provided with an axially extending internal threaded hole, and one end of the pull rod connected to the second trigger member is provided with an external threaded structure threadably matched with the internal threaded hole.

7. The electric linear actuator according to claim 3, characterized in that: The circuit board is fixed on the second fixing plate. The first fixing plate and the second fixing plate are spaced apart in the axial direction and the micro switch assembly is arranged between the first fixing plate and the second fixing plate.

8. The electric linear actuator according to any one of claims 1 to 4, characterized in that: The screw nut is provided with an axially penetrating clearance hole, and the pull rod passes through the clearance hole and is slidably matched with the clearance hole.

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