Multi-stage electric actuator

Abstract

The present invention provides a multi-stage electric push rod, which is composed of three-stage push rods. The first-stage push rod is a fixed part, in which circuits, batteries, motors and other components are stored. The second-stage push rod is an extendable part, which is sleeved on the outside of the first-stage push rod through a clearance fit. The first-stage push rod is connected and drives the second-stage push rod through two ropes. The third-stage push rod is also an extendable part, which is sleeved on the outside of the second-stage push rod through a clearance fit. The first-stage push rod is connected and drives the third-stage push rod through two ropes. The three-stage push rod of the electric push rod realizes relative motion through a moving pair, and the principle is similar to the telescopic arm of a crane, with a large telescopic range and easy storage.

Description

Technical Field

[0001] The present invention relates to the technical field of realizing the conversion from rotary motion to linear reciprocating motion by controlling a rotary motor, and in particular to a structure in which a push rod can be rapidly and widely extended by cooperating ropes and pulleys between multi-stage push rods. Background Art

[0002] Traditional drives are divided into hydraulic drives, electric drives, and pneumatic drives. As a typical electric drive device, electric linear actuators are widely used in the mechanical field and are used as actuators in various process flows to facilitate long-distance, high-precision, and automated control of machinery.

[0003] The electric push rod is composed of a drive motor, a reduction gear, a screw, a nut, a guide sleeve, a push rod, a slide, a spring, a housing, a turbine, a micro-control switch, etc. The electric push rod is powered by the electric motor, the reduction gear has a deceleration function, and the screw rotates on the lead screw nut to convert the motor's rotational motion into linear motion. The push rod's telescopic motion can be achieved by controlling the forward and reverse rotation of the motor. The stroke and moving rate of the electric push rod are achieved by controlling the length of the lead screw and the speed of the motor. To achieve other motion requirements, such as completing the entire stroke in steps (i.e., stop-and-go), an encoder is used. Complex movements such as rotation and shaking can be achieved through various levers, rockers or connecting rods.

[0004] At present, all electric push rods are single-section telescopic structures, and the stroke is usually between 100 and 400 mm. Special strokes need to be designed separately, and the no-load running speed is 4mm to 35mm / s. Due to these characteristics of electric push rods, electric push rods will have many inconveniences in some application scenarios. For example, in application scenarios with long spans, the push rod needs to be designed to be very long. Due to the special design, it may have an adverse effect on the timeliness and cost of application. At the same time, because the telescopic rod is too long, the motor speed is too small, which will cause the motor to extend more slowly. If it is too large, it will cause the motor to overheat and affect the life of the motor. In addition, the traditional electric push rod overload protection method is to consider the specified range when selecting the thrust of the electric push rod, but the electric push rod itself does not have the function of overload protection, so when overloaded, it will directly cause difficult to repair damage to the electric push rod.

[0005] At present, the improvement of the function of the electric push rod is mainly achieved by combining and controlling it with a rocker, lever, etc. There is only local structural optimization of the electric push rod itself, such as the selection of different types of screws, but innovative optimization of the structure is not involved at present. Summary of the invention

[0006] The purpose of the present invention is to provide a multi-stage electric push rod in order to achieve the effects of rapid extension and retraction, large extension range, overload protection and the like of the electric push rod.

[0007] The purpose of the present invention is achieved in this way: the multi-stage electric push rod is composed of three-stage push rods, the first-stage push rod is a fixed part, and the circuit, battery, motor and other components are stored inside; the second-stage push rod is an extendable part, which is sleeved on the outside of the first-stage push rod through a clearance fit, and the first-stage push rod is connected to and drives the second-stage push rod through two ropes; the third-stage push rod is also an extendable part, which is sleeved on the outside of the second-stage push rod through a clearance fit, and the first-stage push rod is connected to and drives the third-stage push rod through two ropes.

[0008] Furthermore, the first-stage push rod is the main part of the entire electric push rod, including the circuit battery compartment and the driving device part. The circuit battery compartment has space for placing the circuit board and the battery, which is convenient for the electric push rod to realize remote control. The circuit battery compartment part is connected to the motor housing and the motor cover by screws, and the motor housing and the motor cover are also connected by screws. The driving part includes a motor, a lead screw, a slide, a rope, etc., and the slide consists of a lead screw nut, a lead screw nut shell, and a pulley. The motor is controlled by the circuit board to control the speed, direction, intermittent, etc. The rotation of the motor drives the lead screw to rotate, and the lead screw nut shell limits the axial rotation of the lead screw nut, so that the slide as a whole moves along the axial direction of the lead screw. The pulley installed on the slide has the function of a movable pulley. The two ropes are respectively connected to the end of the first-stage push rod and the top of the motor. A notch is opened on one side of the first-stage push rod. The two ropes bypass the pulley from two directions, pass through the notch, and are connected to the second-stage push rod. There is a rope fixing block on the other side of the first-stage push rod, which is fixed with two other ropes, which bypass the pulley of the second-stage push rod and connect the third-stage push rod.

[0009] Furthermore, the second-stage push rod is composed of a tube body and a two-part pulley structure. The second-stage push rod is sleeved outside the first-stage push rod and serves as the push rod of the entire electric push rod. There are two places for fixing ropes on one side of the second-stage push rod to fix the ropes that bypass the pulleys of the first-stage push rod to ensure the extension and retraction movement of the second-stage push rod relative to the first-stage push rod. A mandrel is installed at each end of the other side, and a pulley is installed on the mandrel. Due to the movement of the second-stage push rod, it has the function of a movable pulley. The two ropes led out of the rope fixing block of the first-stage push rod bypass the two pulleys and are connected to the third-stage push rod, realizing the movement of the third-stage push rod relative to the second-stage push rod.

[0010] Furthermore, the third-stage push rod is mainly composed of a main body, a secondary body, and two clamping rings, and serves as the push rod of the entire electric push rod. The main body and the secondary body are connected by the clamping ring, and there is a rope fixing block structure on the secondary body, where two ropes drawn from the first-stage push rod fixing block and bypassing the pulley of the second-stage push rod are fixed, and the movement of the slide drives the movement of the second-stage push rod, and the movement of the second-stage push rod drives the movement of the third-stage push rod, and the displacement of the slide is magnified twice on the second-stage push rod and four times on the third-stage push rod, producing the effect of equal extension and retraction of the second and third-stage push rods.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the three-stage push rod of the electric push rod realizes relative movement through a moving pair, and the principle is similar to the telescopic arm of a crane, with a large telescopic range and easy storage. The ratio of its length when fully retracted to its length when fully extended is 1:2.39, and the maximum extendable length is 607.83mm. The three-stage push rod of the electric push rod can move synchronously, and the moving distance of the lead screw nut: the moving distance of the second-stage push rod: the moving distance of the third-stage push rod is 1:2:4. The telescopic speed of the push rod is 4 times the moving speed of the nut, which can realize rapid telescopic extension of the push rod. The three-stage push rods realize relative movement through a movable pulley structure, and the rope connection makes the structure have a certain elasticity. When the load is too large, the overload protection function can be realized by the breaking of the rope. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the overall structure of the invention;

[0013] Figure 2 , Figure 3 Schematic diagram of the overall structure of the first-stage push rod;

[0014] Figure 4 It is the overall structural diagram of the second-stage push rod;

[0015] Figure 5 It is the overall structure diagram of the third-stage push rod;

[0016] Figure 6 , Figure 7 It is a schematic diagram of the driving structure of the first to second stage push rod;

[0017] Figure 8 , Fig. 9 It is a schematic diagram of the first to third stage push rod driving structure;

[0018] In the figure, 1 is the first-stage push rod; 2 is the second-stage push rod; 3 is the third-stage push rod; 4 is the circuit battery compartment; 5 is the motor housing; 6 is the motor cover; 7 is the lead screw nut and the lead screw nut housing; 8 is the lead screw; 9 is the motor; 10 is the first-stage push rod pulley; 11 is the rope fixing block; 12 is the second-stage push rod tube body; 13 is the second-stage push rod small-diameter end spindle and pulley assembly; 14, 15 is the second-stage push rod large-diameter end spindle and pulley assembly; 16 is the third-stage push rod auxiliary tube body; 17 is the retaining ring; 18 is the third-stage push rod main body; 19 is the aluminum sleeve; 20 is the second-stage push rod extension rope; 21 is the second-stage push rod retraction rope; 22 is the third-stage push rod retraction rope; 23 is the third-stage push rod extension rope. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0020] like Figure 1 As shown, the multi-stage electric push rod is composed of a first-stage push rod 1, a second-stage push rod 2 and a third-stage push rod 3.

[0021] like Figure 2 , Figure 3 As shown, a control circuit is placed in the battery circuit compartment 4, and the circuit is connected to the motor 9 to control it to rotate, driving the lead screw 8 to rotate, and the lead screw nut and the lead screw nut housing 7 are restricted from rotating in the motor housing 5. Under the rotation of the lead screw 8, the lead screw nut and the lead screw nut housing 7 and the first-stage push rod pulley 10 form a slide structure, which translates along the axial direction of the lead screw. The pulley 10 has two grooves that can pass around two ropes. There is a notch on one side of the first-stage push rod, and a rope fixing block 11 is installed on the other side. The rope passes through the hole on the fixing block, and the passed part is pinched with an aluminum sleeve 19 to achieve the effect of fixing the rope.

[0022] like Figure 4 As shown, one end of the second-stage push rod is provided with a pulley structure 14, 15 and 13 respectively.

[0023] like Figure 5 As shown, the third-stage push rod is composed of an auxiliary tube body 16, a clamp ring 17 and a main tube body 18. The main tube body and the auxiliary tube body are fixed together by the clamp ring, and a fixing block structure for fixing the rope is provided inside the auxiliary tube body.

[0024] The second level push rod movement principle: Figure 6 , Figure 7 As shown, the starting end of the second-stage push rod extension rope 20 is fixed at the middle part of the first-stage push rod 1, that is, the starting end of the slide groove stroke, bypasses the first-stage push rod pulley 10, and its end is connected to the large-diameter end of the second-stage push rod tube body 12, that is, the end with a larger tube diameter, and both are fixed by pinching with an aluminum sleeve 19. The first-stage push rod pulley 10 serves as a movable pulley. During the movement of the slide toward the end of the stroke, the pulley 10 pulls the rope 20, and the end of the rope 20 pulls the second-stage push rod to extend, and the extension speed and distance are both twice the movement of the slide; the starting end of the second-stage push rod retraction rope 21 is fixed at the end of the slide groove stroke, bypasses the first-stage push rod pulley 10, and is connected to the small-diameter end of the second-stage push rod tube body 12, that is, the end with a smaller tube diameter, and both are fixed by pinching with an aluminum sleeve 19. During the movement of the slide toward the starting end, the pulley 10 pulls the rope 21, and the end of the rope 21 pulls the second-stage push rod to retract, and the retraction speed and distance are both twice the movement of the slide.

[0025] The third level of push rod movement principle: Figure 8 , Fig. 9As shown, the starting ends of the extension rope 23 and the retraction rope 22 of the third-stage push rod are fixed on the rope fixing block 11 of the first-stage push rod, the extension rope 23 bypasses the pulley structure 14, 15 at the small diameter end of the second-stage push rod, and the end is connected to the rope fixing block structure on the inner side of the third-stage push rod auxiliary tube body 16, and both ends are pinched and fixed with aluminum sleeves 19. The movement of the second-stage push rod extending makes the pulley structures 14, 15 have the function of movable pulleys. During the extension process, the pulley 15 pulls the rope 23, and the rope 23 pulls the third-stage push rod auxiliary tube body to extend, thereby driving the entire third-stage push rod to extend, and its extension speed and distance are both twice that of the extension of the second tube body; the retraction rope 22 bypasses the pulley structure 13 at the root of the second-stage push rod, and the end is connected to the third-stage push rod. The retraction movement of the second-stage push rod makes the pulley structure 13 have the function of a movable pulley, and during the retraction process, the rope 22 is pulled, and the rope 22 pulls the third-stage push rod to retract, and the retraction speed and distance are both twice that of the retraction of the second-stage push rod. Finally, the speed and distance of extension and retraction of the third-stage push rod are four times that of the first-stage push rod slide, and the second-stage and third-stage push rods extend and retract in equal proportion.

Claims

1. Multi-stage electric linear actuator, characterized by: It includes a first-stage push rod, a second-stage push rod and a third-stage push rod. The first-stage push rod is a fixed part, in which a circuit, a battery and a motor are stored. The second-stage push rod is an extendable part, which is sleeved on the outside of the first-stage push rod through a clearance fit. The first-stage push rod is connected to and drives the second-stage push rod through two ropes. The third-stage push rod is an extendable part, which is sleeved on the outside of the second-stage push rod through a clearance fit. The first-stage push rod is connected to and drives the third-stage push rod through two ropes. The first-stage push rod includes a circuit battery compartment and a driving device part. The circuit battery compartment is provided with a space for placing a circuit board and a battery. The circuit battery compartment part is connected to the motor housing and the motor cover by screws, and the motor housing and the motor cover are also connected by screws; the driving part includes a motor, a lead screw, a slide, and a rope. The slide includes a lead screw nut, a lead screw nut shell, and a pulley; the motor is controlled by the circuit board, and the rotation of the motor drives the lead screw to rotate. The lead screw nut shell limits the axial rotation of the lead screw nut, thereby making the slide as a whole move along the axial direction of the lead screw. The pulley installed on the slide has the function of a movable pulley, and two ropes are respectively connected to the end of the first-stage push rod and above the motor. A notch is opened on one side of the first-stage push rod. The two ropes pass around the pulley from two directions, pass through the notch, and are connected to the second-stage push rod; a rope fixing block is provided on the other side of the first-stage push rod, and two other ropes are fixed thereon, which respectively pass around the pulley on the second-stage push rod and are connected to the third-stage push rod; The second-stage push rod includes a tube body and a two-part pulley structure. The second-stage push rod is sleeved outside the first-stage push rod. There are two rope fixing locations on one side of the second-stage push rod to fix the rope that bypasses the pulley of the first-stage push rod, so as to ensure the extension and retraction movement of the second-stage push rod relative to the first-stage push rod; both ends of the other side of the second-stage push rod are respectively equipped with a spindle, and a pulley is mounted on the spindle. Due to the movement of the second-stage push rod, it has the function of a movable pulley. The two ropes led out of the rope fixing block of the first-stage push rod bypass the two pulleys and are connected to the third-stage push rod, so as to realize the movement of the third-stage push rod relative to the second-stage push rod; The third-stage push rod includes a main body, a sub-tube body, and two clamping rings. The main body and the sub-tube body are connected by the clamping rings. There is a rope fixing block structure on the sub-tube body. Two ropes led out from the first-stage push rod fixing block and bypassed around the second-stage push rod pulley are fixed here. The movement of the slide drives the movement of the second-stage push rod, and the movement of the second-stage push rod drives the movement of the third-stage push rod. The displacement of the slide is magnified twice on the second-stage push rod and four times on the third-stage push rod, resulting in the effect of proportional extension and retraction of the second and third-stage push rods.

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