Electric cylinder with force feedback function

Abstract

The utility model relates to an electric cylinder with a force feedback function, which comprises an outer tube extending left and right and a nut assembled in the outer tube in a guiding and sliding manner, a push rod is fixedly mounted on the nut, and the push rod extends out of the right end of the outer tube; the lead screw and the gearbox are installed in the nut in a penetrating mode, the gearbox comprises a box body fixedly arranged at the left end of the outer pipe, a driving gear and a driven gear, the driving gear and the driven gear are arranged in the box body, the lead screw is fixedly sleeved with the driven gear, and a protruding ring protruding leftwards is arranged on the inner side, close to the center, of the driven gear. A flange sleeve is fixed on the left side of the box body; a fixed support lug is fixed on the left side of the flange sleeve; a pressure sensor is arranged in the fixed supporting lug, and the left side of the pressure sensor abuts against the fixed supporting lug; the electric cylinder further comprises a thrust bearing, the thrust bearing comprises an inner ring arranged outside the convex ring in a sleeving mode, the driven gear abuts against the inner ring leftwards, the electric cylinder further comprises an outer ring installed in the flange sleeve, and the outer ring directly or indirectly abuts against the pressure sensor leftwards.

Description

Technical Field

[0001] The utility model relates to a device for converting rotary motion into linear motion, in particular to an electric cylinder with a force feedback function. Background Art

[0002] The principle of an electric cylinder is to accurately and quantitatively transfer the rotary motion of a servo motor to a lead screw through a transmission mechanism, convert the rotary motion of the lead screw into the linear motion of a push rod through a lead screw nut mechanism, and push an object by the push rod. However, there are still imperfections in the actual application of the electric cylinder. For example, when the push rod extends to push an object, the object may be stuck and unable to be pushed, but the electric cylinder still continues to work, ultimately resulting in damage to the electric cylinder or the object.

[0003] To solve such problems, in the prior art, there is a method of arranging a pressure sensor at the end of the push rod. When the push rod pushes an object, the pressure sensor is pressed to output a pressure signal, and the start and stop of the electric cylinder are controlled according to the pressure signal. For example, the utility model patent with the authorization announcement number CN204808084U adopts this method.

[0004] The disadvantage of this method in the prior art is that during use, the pressure sensor is arranged at the end of the push rod and moves back and forth frequently with the push rod during use, which is not conducive to the wiring of the pressure sensor. Summary of the Utility Model

[0005] The utility model provides an electric cylinder with a force feedback function to solve the technical problem of inconvenient wiring caused by the frequent reciprocating movement of the pressure sensor with the push rod in the prior art.

[0006] To solve the above problems, the electric cylinder with a force feedback function provided by the utility model adopts the following technical solution: An electric cylinder with a force feedback function, comprising:

[0007] An outer tube extending left and right and a nut slidably and guidingly assembled in the outer tube. A push rod is fixedly installed on the nut and extends out from the right end of the outer tube;

[0008] A lead screw, inserted into the nut; further comprising:

[0009] A gear box, including a box body fixedly arranged at the left end of the outer tube and a driving gear and a driven gear arranged in the box body. The driven gear is fixedly sleeved outside the lead screw, and a convex ring protruding leftward is arranged on the inner side of the driven gear close to the center;

[0010] A fixed support ear and a flange sleeve. The flange sleeve is fixedly installed on the left side of the box body, and the fixed support ear is fixedly installed on the left side of the flange sleeve;

[0011] A pressure sensor, located in the fixed support ear, and the left side of the pressure sensor abuts against the fixed support ear;

[0012] The thrust bearing includes an inner ring sleeved outside the convex ring, the driven gear presses against the inner ring towards the left, and also includes an outer ring installed in the flange sleeve, and the outer ring presses directly or indirectly against the pressure sensor towards the left.

[0013] The beneficial effects are as follows: When the electric cylinder works, the push rod extends and drives the movable lug to move. The load received by the movable lug is sequentially transmitted to the pressure sensor through the push rod, nut, lead screw, driven gear, and thrust bearing. The pressure sensor can measure the magnitude of the external load of the electric cylinder. Since the pressure sensor is arranged at the left end of the electric cylinder and does not need to move frequently with the push rod, it is convenient for wiring. In the present utility model, a thrust bearing is used to transmit the axial load, and the thrust bearing has good performance in bearing the axial load. In the present utility model, the driven gear is fixedly connected to the lead screw and also fixedly connected to the inner ring at the same time. The outer ring and the driven gear not only play a role in driving the lead screw to rotate but also can transmit the axial load.

[0014] Further, a partition plate is provided on the pressure sensor and is located between the pressure sensor and the outer ring. The partition plate is slidably assembled in the flange sleeve along the left-right direction.

[0015] Further, a positioning step is provided on the lead screw towards the left, and the right side of the driven gear abuts against the positioning step.

[0016] A pressing ring is also threadedly assembled on the lead screw. The pressing ring is used to press the convex ring to cooperate with the positioning step to clamp the driven gear. The pressing ring is located inside the inner ring. The pressing ring and the positioning step cooperate to clamp and fix the driven gear, so that the driven gear and the lead screw move synchronously, thereby being able to transmit the axial load in real time.

[0017] Further, the right side surface of the driven gear is grooved and fixedly installed with a rotary seal. The rotary seal has a sealing lip that contacts the box body to achieve sealing.

[0018] Further, a power mechanism is fixedly installed on the right side of the box body. There are two power mechanisms and they are evenly distributed around the central axis of the outer tube.

[0019] Further, the lead screw is a ball screw, the nut is a ball nut that cooperates with the ball screw, and the power mechanism includes a speed-limiting brake.

[0020] Further, an absolute encoder is provided on the left side of the box body. The absolute encoder is arranged opposite to the driving gear left and right and is fixedly connected coaxially. Description of the Drawings

[0021] By reading the following detailed description with reference to the accompanying drawings, the above and other objects, features, and advantages of the exemplary embodiments of the present utility model will become readily understandable. In the drawings, several embodiments of the present utility model are shown in an exemplary rather than restrictive manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein:

[0022] Figure 1 Schematic diagram of an electric cylinder with a force feedback function in a state where the push rod is not extended;

[0023] Figure 2 Front view of an electric cylinder with a force feedback function;

[0024] Figure 3 For Figure 2 Cross-sectional view of section A-A in

[0025] Figure 4 For Figure 3 Enlarged view at B in

[0026] Figure 5 For Figure 3 Enlarged view at C in

[0027] Figure 6 Schematic diagram of an electric cylinder with a force feedback function after removing some structures;

[0028] Figure 7 For Figure 6 Enlarged view at D in

[0029] Figure 8 Schematic diagram of an electric cylinder with a force feedback function in a state where the push rod is extended.

[0030] Explanation of reference numerals:

[0031] 1. Outer tube; 2. Nut; 3. Push rod; 4. Movable ear; 5. Lead screw; 6. Gearbox; 7. Fixed ear; 8. Thrust bearing; 81. Inner ring; 82. Outer ring; 9. Pressure sensor; 10. Reducer; 11. Speed limit brake; 12. Servo motor; 13. Housing; 14. Driving gear; 15. Driven gear; 16. Rotary seal; 17. Positioning step; 18. Compression ring; 19. Partition; 20. Absolute encoder; 21. Connecting flange; 22. Flange sleeve; 23. Fixed sleeve; 24. Convex ring. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present utility model.

[0033] Next, the principles and spirits of the present utility model will be elaborated in detail with reference to several representative embodiments of the present utility model.

[0034] An embodiment of an electric cylinder with a force feedback function:

[0035] As Figure 1-8 shown, an electric cylinder with a force feedback function (hereinafter simply referred to as an electric cylinder) includes an outer tube 1, a nut 2, a push rod 3, a movable ear 4, a lead screw 5, a gearbox 6, a fixed ear 7, a thrust bearing 8, a pressure sensor 9, and a power mechanism. There are two sets of power mechanisms, and the two sets of power mechanisms are evenly distributed around the central axis of the outer tube 1.

[0036] As Figures 2 to 5 shown, the outer tube 1 is a tube body extending in the left-right direction and open at both ends. The right end of the outer tube 1 allows the push rod 3 to extend and retract. It should be noted that "left" and "right" are only artificially defined for convenience of description and do not limit the specific structure of the electric cylinder. A fixed sleeve 23 is fixedly installed at the right end of the outer tube 1. The inner wall of the fixed sleeve 23 is grooved and a seal is installed. The seal contacts the outer peripheral surface of the push rod 3 to achieve sealing. A connecting flange 21 is welded to the left end of the outer tube 1.

[0037] The nut 2 is guided and slidably assembled in the outer tube 1 and will not rotate relative to the outer tube 1. Specifically, a chute is provided on the inner wall of the outer tube 1, and a guide block that is in guiding cooperation with the chute is fixed outside the nut 2. Here, the nut 2 is a ball nut.

[0038] The push rod 3 is fixedly installed at the right end of the nut 2, and the movable ear 4 is fixedly installed at the right end of the push rod 3. The nut 2 drives the push rod 3 and the movable ear 4 to move left and right. Among them, the inside of the push rod 3 is hollow to accommodate the lead screw 5. The movable ear 4 is threadedly installed at the right end of the push rod 3. Among them, the connection method and working method of the outer tube 1, the nut 2, the push rod 3, and the movable ear 4 are the same as those in the prior art and will not be elaborated here.

[0039] The lead screw 5 is inserted into the nut 2, and at the same time, the lead screw 5 penetrates into the push rod 3. The lead screw 5 and the nut 2 cooperate with each other. When the lead screw 5 rotates, it can drive the nut 2 to move left and right. Here, the lead screw 5 is a ball screw. The left end of the lead screw 5 passes through the outer tube 1.

[0040] The gearbox 6 is located at the left end of the outer tube 1. Specifically, the gearbox 6 includes a housing 13 fixedly installed at the left end of the outer tube 1, and the right end of the housing 13 is connected to the connecting flange 21 at the left end of the outer tube 1 by bolts. A bearing is installed between the lead screw 5 and the housing 13 to position the rotation of the lead screw 5.

[0041] An active gear 14 and a driven gear 15 are rotatably installed in the housing 13. The active gear 14 and the driven gear 15 mesh with each other. Among them, the active gear 14 is a small gear and the driven gear 15 is a large gear to achieve torque reduction. The driven gear 15 is sleeved outside the lead screw 5, and there is non-rotating between the driven gear 15 and the lead screw 5. The driven gear 15 can drive the lead screw 5 to rotate. Specifically, non-rotating assembly between the driven gear 15 and the lead screw 5 can be achieved through splines and key grooves. To make the driven gear 15 and the lead screw 5 relatively fixed in the left-right direction, a positioning step 17 facing left is provided on the lead screw 5, the right end of the driven gear 15 abuts against the positioning step 17, and a compression ring 18 is threadedly installed on the lead screw 5. The compression ring 18 presses against the left end of the driven gear 15, and the driven gear 15 is pressed by the compression ring 18 and the positioning step 17.

[0042] As Figure 4 shown, a groove is opened on the right side of the driven gear 15 and a rotary seal 16 is installed. The sealing lip of the rotary seal 16 contacts the housing 13 to achieve sealing. The left side of the driven gear 15 has a convex ring 24 protruding leftward.

[0043] An absolute encoder 20 is fixedly installed at the left end of the housing 13. The absolute encoder 20 is directly opposite to the active gear 14 left and right, and can detect the number of rotation turns of the active gear 14, and thus can record the running position of the push rod 3 in real time. The absolute encoder 20 here is a mechanical multi-turn absolute encoder, which is fixed and coaxial with the active gear 14 to record the number of rotation turns of the active gear 14. The active gear 14 and the driven gear 15 are meshed and driven at a fixed speed ratio, indirectly recording the number of rotation turns of the driven gear 15 and the lead screw 5. The lead screw 5 and the nut 2 have a fixed lead, and the displacement of the nut 2 and the push rod 3 is calculated to record the running position of the push rod 3. This kind of encoder does not need to replace the battery regularly, and is more resistant to impact and vibration, expanding the application scenarios of the electric cylinder. The absolute encoder 20 is prior art and will not be elaborated here.

[0044] As Figure 4 shown, the fixed support ear 7 is fixedly installed on the left side of the housing 13 through a flange sleeve 22. Specifically, a threaded hole is opened on the left side of the housing 13, and bolt through holes are opened on the fixed support ear 7 and the flange sleeve 22. The bolt passes through the fixed support ear 7 and the flange sleeve 22 and then penetrates into the threaded hole to fix the fixed support ear 7, the flange sleeve 22 and the housing 13 together.

[0045] The thrust bearing 8 is installed between the flange sleeve 22 and the convex ring 24. Specifically, the inner ring 81 of the thrust bearing 8 is sleeved outside the convex ring 24, and the outer ring 82 of the thrust bearing 8 is installed inside the flange sleeve 22. Among them, the left end face of the outer ring 82 is located on the left side of the lead screw 5 and the pressing ring 18, so that the thrust bearing 8 can apply pressure to the pressure sensor 9.

[0046] The pressure sensor 9 is located inside the flange sleeve 22; in the left-right direction, the pressure sensor 9 is located between the convex ring 24 and the thrust bearing 8. When the thrust bearing 8 receives a leftward acting force, it will press against the pressure sensor 9 to detect the pressure received. Specifically, a partition plate 19 is fixedly installed on the pressure sensor 9. The partition plate 19 is located between the pressure sensor 9 and the thrust bearing 8, and the partition plate 19 is fixedly connected to the pressure sensor 9 by bolts. The partition plate 19 is assembled in the flange sleeve 22 to slide in the left-right direction. Specifically, a slider is fixed on the outside of the partition plate 19, and a sliding groove is provided in the flange sleeve 22. The guiding sliding of the partition plate 19 is realized through the cooperation of the slider and the sliding groove. The left end of the pressure sensor 9 is pressed against the fixed support ear 7. Among them, the pressure sensor 9 can select a pressure sensor already available on the market.

[0047] The power mechanism includes a speed reducer 10, a speed limit brake 11, and a servo motor 12 that are connected together. The speed reducer 10 is fixedly installed on the right side surface of the box body 13, and the output shaft of the speed reducer 10 is connected to the driving gear 14. The speed limit brake 11 is connected to the right side of the speed reducer 10. When encountering an accidental control failure of the system, the speed limit brake 11 can limit the telescopic speed of the electric cylinder to ensure the safety of the equipment and personnel. The servo motor 12 is connected to the right side of the speed limit brake 11. The speed reducer 10, the speed limit brake 11, and the servo motor 12 are all existing technologies and will not be elaborated here.

[0048] During use, two servo motors 12 are synchronously controlled. The rotation speed and torque are transmitted to each speed reducer 10 through each speed limit brake 11. After the speed reduction and torque increase of the gearbox 6, the lead screw 5 is finally driven to rotate. When the nut 2 is restricted from rotating by the outer tube 1, the push rod 3 makes a linear motion. When the servo motor 12 rotates forward, the push rod 3 extends, as Figure 8 shown; when the servo motor 12 rotates in reverse, the push rod 3 retracts.

[0049] The axial load received by the movable support ear 4 from the outside is transmitted to the pressure sensor 9 through the push rod 3, the nut 2, the lead screw 5, the driven gear 15, and the thrust bearing 8. The pressure sensor 9 can measure the magnitude of the external load of the electric cylinder. Since the pressure sensor 9 is installed at the fixed end of the electric cylinder, it does not need to move frequently with the push rod 3, which is convenient for wiring.

[0050] When the rotational speed of the speed limit brake 11 is lower than its starting operating speed, the speed limit brake 11 does not operate; when a system accidental control failure occurs, since the ball screw cannot self-lock, under the action of an external force, the screw 5 drives the nut 2 to rotate in the reverse direction, and after the speed is increased in reverse through the gearbox 6, when the rotational speed of the speed limit brake 11 is higher than its starting operating speed, the speed limit brake 11 starts to brake and limit the speed.

[0051] In the present utility model, since the power mechanism is installed on the right side of the box body 13, a folded double-power symmetrical arrangement is achieved, and the appearance is beautiful. Due to the form of realizing the double-power mechanism drive, the power output realizes double redundancy, improving the reliability and braking safety of the electric cylinder, and the servo motor 12, the speed limit brake 11, and the speed reducer 10 can be replaced with load, improving the convenience of maintenance.

[0052] In other embodiments, if only to realize the real-time monitoring of the load borne by the electric cylinder, only one set of power mechanisms may be provided.

[0053] In other embodiments, the fixing method between the driven gear and the screw can be changed. For example, the driven gear and the screw can be fixed together by welding or other means.

[0054] In addition, in the description of this specification, the meaning of "a plurality of" is at least two, such as two, three or more, etc., unless otherwise clearly and specifically defined.

Claims

1. An electric cylinder with force feedback function, comprising: An outer tube (1) extending left and right and a nut (2) which is slideably assembled in the outer tube (1) and a push rod (3) is fixedly mounted on the nut (2) and extends from the right end of the outer tube (1); The lead screw (5) is inserted into the nut (2); and is characterized in that it further comprises: The gear box (6) comprises a box body (13) fixedly arranged at the left end of the outer tube (1), and a driving gear (14) and a driven gear (15) arranged in the box body (13); the driven gear (15) is fixedly sleeved on the outside of the lead screw (5); and the driven gear (15) has a convex ring (24) protruding to the left on the inner side near the center; A fixed support ear (7) and a flange sleeve (22), wherein the flange sleeve (22) is fixedly mounted on the left side of the box body (13), and the fixed support ear (7) is fixedly mounted on the left side of the flange sleeve (22); A pressure sensor (9) is located in the fixed support ear (7), and the left side of the pressure sensor (9) abuts against the fixed support ear (7); The thrust bearing (8) includes an inner ring (82) mounted on the outside of the convex ring (24), the driven gear (15) pressing on the inner ring (82) toward the left, and an outer ring (81) installed in the flange sleeve (22), the outer ring (81) pressing on the pressure sensor (9) toward the left directly or indirectly.

2. The electric cylinder with force feedback function according to claim 1, characterized in that: The pressure sensor (9) is provided with a partition (19) located between the pressure sensor (9) and the outer ring (81), and the partition (19) is guided and slidably assembled in the flange sleeve (22) along the left-right direction.

3. The electric cylinder with force feedback function according to claim 1, characterized in that: The lead screw (5) is provided with a leftward positioning step (17), and the right side of the driven gear (15) abuts against the positioning step (17); The lead screw (5) is also threadedly mounted with a clamping ring (18), which is used to press the convex ring (24) to cooperate with the positioning step (17) to clamp the driven gear (15); the clamping ring (18) is located on the inner side of the inner ring (82).

4. The electric cylinder with force feedback function according to claim 1, characterized in that: A groove is formed on the right side surface of the driven gear (15) and a rotating seal (16) is fixedly mounted thereon. The rotating seal (16) has a sealing lip that contacts the housing (13) to achieve sealing.

5. The electric cylinder with force feedback function according to any one of claims 1 to 4, characterized in that: A power mechanism is fixedly mounted on the right side of the box body (13), and two power mechanisms are arranged and evenly distributed around the central axis of the outer tube (1).

6. The electric cylinder with force feedback function according to claim 5, characterized in that: The lead screw (5) is a ball screw, the nut (2) is a ball nut matched with the ball screw, and the power mechanism includes a speed limiting brake (11).

7. The electric cylinder with force feedback function according to any one of claims 1 to 4, characterized in that: An absolute value encoder (20) is provided on the left side of the box body (13), and the absolute value encoder (20) is arranged opposite to the driving gear (14) on the left and right and is coaxially fixedly connected.

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