Electric cylinder with built-in force sensor

Abstract

The utility model belongs to the technical field of mechanical transmission, and particularly relates to an electric cylinder with a built-in force sensor, which comprises a lead screw assembly, a force sensor assembly and a force sensor assembly, the lead screw assembly comprises a nut and a screw rod, and the nut is movably sleeved on the outer side of the screw rod; the piston rod is fixedly connected with the nut; the bearing seat is arranged on the screw rod in a sleeving mode, the front end and the rear end of the bearing seat in the axial direction are connected with first bearings correspondingly, and the first bearings are connected with the screw rod; and the force sensor is arranged on the screw rod in a sleeving manner, and the force sensor is connected with the bearing seat. The axial tension and the axial pressure from the screw rod are transmitted to the bearing seat through the two first bearings respectively, and then the tension and the pressure are transmitted to the force sensor through the bearing seat respectively, so that output of pressure signals and pressure signals is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of mechanical transmission, and in particular relates to an electric cylinder with a built-in force sensor. Background Art

[0002] In industrial applications, electric cylinders are an important transmission device and are widely used in various automated production lines and mechanical equipment. In order to achieve high-precision force output and ensure the stability and accuracy of the electric cylinder during the entire movement process, the configuration of the pressure sensor is particularly important. In existing electric cylinders with force sensor structures, the force sensor is usually located outside the cylinder barrel. The external force sensor can only detect the pressure when the telescopic rod of the electric cylinder is extended. When the telescopic rod of the electric cylinder is retracted, the external force sensor will not detect the tension of the telescopic rod. In addition, when the electric cylinder is working, the external force sensor will move back and forth with the piston rod, causing the cable of the force sensor to move accordingly. During use, the cable will deform multiple times after multiple reciprocating movements, causing damage to the cable, which in turn affects the normal use of the entire transmission equipment. Utility Model Content

[0003] The technical problem to be solved by the utility model is that the existing electric cylinder with an external force sensor structure is easily damaged and can only detect pressure signals but cannot detect tension signals.

[0004] To this end, the utility model provides an electric cylinder with a built-in force sensor, which transmits the tension and pressure to the force sensor through the bearing seats via two first bearings, thereby realizing the output of the pressure signal and the pressure signal.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] An electric cylinder with a built-in force sensor, comprising:

[0007] A screw assembly, the screw assembly comprising a nut and a screw, the nut being movably sleeved on the outside of the screw;

[0008] A piston rod, wherein the piston rod is fixedly connected to the nut;

[0009] A bearing seat, wherein the bearing seat is sleeved on the screw rod, and the front and rear ends of the bearing seat are respectively connected to first bearings in the axial direction, and the first bearing is connected to the screw rod;

[0010] A force sensor is sleeved on the screw rod and connected to the bearing seat.

[0011] Furthermore, it also includes:

[0012] A second bearing is sleeved on the screw rod.

[0013] Furthermore, the first bearing is a thrust cylindrical roller bearing, and the second bearing is a cylindrical roller bearing.

[0014] Furthermore, a bearing pressure ring is sleeved on the screw rod, a first step surface is formed on the bearing pressure ring, a second step surface is formed on the bearing seat, and the first bearing is located between the first step surface and the second step surface.

[0015] Furthermore, a third step surface is formed on the screw rod, and a locking nut is also sleeved on the screw rod. The locking nut abuts against the bearing pressure ring located on the rear side of the bearing seat, and the third step surface abuts against the bearing pressure ring located on the front side of the bearing seat.

[0016] Furthermore, it also includes:

[0017] A linear bearing and a cylinder, wherein the cylinder is sleeved on the outer side of the piston rod, the linear bearing is arranged between the piston rod and the cylinder, and the linear bearing is connected to the inner wall of the cylinder.

[0018] Furthermore, it also includes:

[0019] A front end cover is arranged at the front end of the cylinder, a limiting member is fixedly arranged on the inner wall of the cylinder, and the front end cover and the limiting member are respectively abutted against two axial ends of the linear bearing.

[0020] Furthermore, it also includes:

[0021] The base is sleeved on the outer side of the screw rod, and the base and the cylinder are connected to two axial ends of the force sensor.

[0022] Furthermore, the second bearing is located between the base and the screw rod.

[0023] Furthermore, it also includes:

[0024] A driving assembly and a reduction assembly, wherein the screw rod is connected to the driving assembly via the reduction assembly.

[0025] The beneficial effects of the utility model are:

[0026] 1. The axial tension and axial pressure from the screw are transmitted to the bearing seat through the two first bearings respectively, and then the tension and pressure are transmitted to the force sensor through the bearing seat respectively to realize the output of pressure signal and pressure signal.

[0027] 2. Adding a second bearing to the screw to share the radial force transmitted by the screw can improve the radial load bearing capacity and accuracy of the electric cylinder while smoothly outputting pressure signals and tension signals.

[0028] 3. The sliding sleeve in the existing electric cylinder is replaced with a linear bearing, thereby changing the sliding friction between the piston rod and the piston rod to rolling friction, reducing the resistance when the piston rod moves and improving the efficiency of the electric cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Figure 1 It is a structural schematic diagram of a preferred embodiment of an electric cylinder with a built-in force sensor of the utility model;

[0031] Figure 2 It is an enlarged schematic diagram of part A of a preferred embodiment of an electric cylinder with a built-in force sensor of the utility model;

[0032] Figure 3 It is an enlarged schematic diagram of part B of the optimal embodiment of an electric cylinder with a built-in force sensor of the utility model.

[0033] In the figure:

[0034] 1. Nut; 2. Screw; 3. Piston rod; 4. Bearing seat; 5. First bearing; 6. Force sensor; 7. Second bearing; 8. Bearing pressure ring; 9. First step surface; 10. Second step surface; 11. Third step surface; 12. Locking nut; 13. Linear bearing; 14. Cylinder; 15. Front cover; 16. Limiting piece; 17. Base; 18. Piston rod head; 19. Piston rod head seat; 20. Drive assembly; 21. Speed ​​reduction assembly. DETAILED DESCRIPTION

[0035] Now the utility model is further described in detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the utility model in a schematic manner, and therefore only show the components related to the utility model.

[0036] In the description of the present utility model, it is necessary to understand that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0037] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] like Figures 1 to 3 As shown, an electric cylinder with a built-in force sensor includes: a screw assembly, the screw assembly includes a nut 1 and a screw 2, the nut 1 is movably sleeved on the outside of the screw 2; a piston rod 3, the piston rod 3 is fixedly connected to the nut 1; a bearing seat 4, the bearing seat 4 is sleeved on the screw 2, and the front and rear ends of the bearing seat 4 are respectively connected to first bearings 5 ​​in the axial direction, the first bearing 5 is connected to the screw 2, the first bearing 5 is suitable for bearing and transmitting axial loads, and the front and rear ends of the bearing seat 4 are pressed by the two first bearings 5 ​​to ensure the reliability of the bidirectional load; a force sensor 6, the force sensor 6 is sleeved on the screw 2, and the force sensor 6 is connected to the rear side of the bearing seat 4 (for example, by screws).

[0039] It should be noted that the working principle of this embodiment is divided into the following two cases:

[0040] In the first case, when the piston rod 3 is subjected to pressure, the pressure is sequentially transmitted to the nut 1, the screw 2, the first bearing 5, and the bearing seat 4, so that the pressure of the bearing seat 4 on the force sensor 6 increases, and the force sensor 6 can detect the magnitude of the pressure. When the nut 1 is subjected to pressure, it will move backwards a certain distance, and the screw 2 will rotate a certain angle at this time, and the relative rotation between the screw 2 and the bearing seat 4 can be achieved through the first bearing 5.

[0041] In the second case, when the piston rod 3 is subjected to tension, the tension is sequentially transmitted to the nut 1, the screw 2, the first bearing 5, and the bearing seat 4, so that the tension of the bearing seat 4 on the force sensor 6 increases, and the force sensor 6 can detect the magnitude of the tension. When the nut 1 is pulled, it will move forward a certain distance, and the screw 2 will rotate a certain angle at this time. The relative rotation between the screw 2 and the bearing seat 4 can be achieved through the first bearing 5.

[0042] Through structural improvement, the utility model can enable the force sensor 6 to detect pressure signals and tension signals and cope with more working conditions.

[0043] The electric cylinder with built-in force sensor also includes a second bearing 7, and the second bearing 7 is sleeved on the screw 2. Specifically, the first bearing 5 is a thrust cylindrical roller bearing, and the second bearing 7 is a cylindrical roller bearing. It should be noted that in the present embodiment, two different types of bearings are selected. Since both pressure and tension are axial forces, the use of thrust cylindrical roller bearings can better transmit axial loads, which is beneficial to improve the measurement accuracy of the force sensor 6. Since thrust cylindrical roller bearings cannot withstand radial loads, by adding cylindrical roller bearings, the radial load of the screw 2 can be borne. Compared with the prior art that only uses cylindrical roller bearings, the first bearing 5 of the utility model is used to withstand axial loads, and the second bearing 7 is used to withstand radial loads transmitted by the screw 2, thereby improving the working stability of the electric cylinder and the force detection accuracy.

[0044] That is to say, the specific path of axial load transmission in this embodiment is: piston rod 3→nut 1→screw 2→first bearing 5→bearing seat 4→force sensor 6; the specific path of radial load transmission in this embodiment is: piston rod 3→nut 1→second bearing 7. The load transmitted by the piston rod 3 is decomposed into axial load and radial load through the first bearing 5 and the second bearing 7, so as to ensure the radial load bearing capacity and accuracy of the electric cylinder under the premise of smoothly outputting pressure signal and tension signal.

[0045] Specifically, the first bearing 5 includes a first inner ring and a first outer ring. The first inner ring is defined as the side close to the bearing seat 4, and the first outer ring is defined as the side far from the bearing seat 4. A plurality of first cylindrical rollers are provided between the first inner ring and the first outer ring. The first cylindrical rollers are used to realize the relative rotation between the first outer ring and the first inner ring. There are two first bearings 5, which are respectively located at the front end and the rear end of the bearing seat 4. In the first bearing 5 located at the front end of the bearing seat 4, the first outer ring is located at the front side of the first inner ring. In the first bearing 5 located at the rear end of the bearing seat 4, the first outer ring is located at the rear side of the first inner ring. As a result, the first bearing 5 can better transmit the bearing load.

[0046] The second bearing 7 includes a second inner ring and a second outer ring, and a plurality of second cylindrical rollers are arranged between the second inner ring and the second outer ring, and the second cylindrical rollers are used to realize the relative rotation between the second outer ring and the second inner ring. In the second bearing 7, the first inner ring is located inside the inner ring of the second outer ring. Thus, the second bearing 7 can better transmit radial loads.

[0047] For example, two bearing pressing rings 8 are sleeved on the screw 2, a first step surface 9 is formed on the bearing pressing ring 8, and a second step surface 10 is formed on the bearing seat 4. The number of the second step surfaces 10 is two, and the two second step surfaces 10 are respectively located at the front and rear ends of the bearing seat 4, the first step surface 9 and the second step surface 10 are arranged oppositely, the first bearing 5 is arranged between the first step surface 9 and the second step surface 10, and the two bearing pressing rings 8 are respectively located at the front and rear sides of the bearing seat 4 in the axial direction. Among them, the first step surface 9 located at the front side of the bearing seat 4 and the second step surface 10 located at the front end of the bearing seat 4 limit the first bearing 5 located at the front side of the bearing seat 4; the first step surface 9 located at the rear side of the bearing seat 4 and the second step surface 10 located at the rear end of the bearing seat 4 limit the first bearing 5 located at the rear side of the bearing seat 4. In addition, the first step surface 9 and the second step surface 10 can better transmit pressure or tension to the bearing seat 4.

[0048] When the screw 2 rotates, it can drive the bearing pressure ring 8 to rotate, and then drive the first outer ring to rotate, while the first inner ring is stationary.

[0049] For example, a third step surface 11 is formed on the screw 2, and a locking nut 12 is fixedly sleeved on the screw 2. The locking nut 12 abuts against the bearing pressure ring 8 located on the rear side of the bearing seat 4, and the third step surface 11 abuts against the bearing pressure ring 8 located on the front side of the bearing seat 4. In this way, the two first bearings 5 ​​and the bearing seat 4 can be limited in the axial direction of the screw 2, so as to better transmit the tension or pressure to the force sensor 6 for detection.

[0050] For example, the electric cylinder with a built-in force sensor also includes a linear bearing 13 and a cylinder barrel 14. The cylinder barrel 14 is sleeved on the outside of the piston rod 3, and the linear bearing 13 is arranged between the piston rod 3 and the cylinder barrel 14. The linear bearing 13 is axially fixedly connected to the inner wall of the cylinder barrel 14. During operation, rolling friction occurs between the linear bearing 13 and the piston rod 3. Compared with the sliding friction between the sliding sleeve and the piston rod 3 in the prior art, the resistance between the linear bearing 13 and the piston rod 3 in this embodiment is smaller, which can greatly improve the efficiency of the electric cylinder.

[0051] For example, the electric cylinder with a built-in force sensor also includes a front end cover 15, which is arranged at the front end of the cylinder barrel 14. A limiting member 16 is fixedly arranged on the inner wall of the cylinder barrel 14. The limiting member 16 includes but is not limited to an elastic retaining ring for a hole. The front end cover 15 and the limiting member 16 are respectively abutted against the two axial ends of the linear bearing 13, which are suitable for ensuring that the linear bearing 13 is fixed relative to the cylinder barrel 14.

[0052] For example, the electric cylinder with a built-in force sensor also includes a base 17, which is sleeved on the outside of the screw 2. The base 17 and the cylinder barrel 14 are respectively connected to the two axial ends of the force sensor 6 to ensure that the force sensor 6 is fixed relative to the cylinder barrel 14. When the piston rod 3 is subjected to tension or pressure, the force sensor 6 can accurately detect the tension and pressure exerted on the screw 2.

[0053] For example, the electric cylinder with a built-in force sensor also includes a piston rod head 18 and a piston rod head seat 19. The piston rod head 18 is embedded in the piston rod 3, and the piston rod head seat 19 is arranged at the end of the piston rod 3 away from the bearing seat 4. The piston rod head 18 and the piston rod head seat 19 are fixedly connected, and the end face of the piston rod head 18 and the end face of the piston rod head seat 19 are abutted against each other and are connected by screws.

[0054] For example, the second bearing 7 is located between the base 17 and the screw rod 2, and is used to bear the radial load transmitted by the screw rod 2 through the second bearing 7, ensuring that the first bearing 5 only bears the axial load.

[0055] For example, the drive assembly 20 and the reduction assembly 21, the screw 2 is connected to the drive assembly 20 through the reduction assembly 21, and the drive assembly 20 is used to drive the screw 2 to rotate through the reduction assembly 21. The drive assembly 20 can drive the screw 2 to rotate through the reduction assembly 21, thereby realizing the telescopic movement of the piston rod 3.

[0056] In summary, the piston rod 3 is subjected to pressure or tension, and transmits the pressure or tension to the nut 1, and the nut 1 further transmits the pressure or tension to the screw 2, while driving the screw 2 to rotate around the axis, and the screw 2 transmits the pressure or tension to the first bearing 5, which transmits the pressure or tension to the bearing seat 4, and further transmits the pressure or tension to the force sensor 6 for detection, thereby realizing the detection of the tension and pressure on the piston rod 3.

[0057] Based on the above ideal embodiments of the utility model, the relevant staff can make various changes and modifications without departing from the technical concept of the utility model through the above description. The technical scope of the utility model is not limited to the content of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An electric cylinder with a built-in force sensor, characterized in that: include: A screw assembly, the screw assembly comprising a nut (1) and a screw (2), the nut (1) being movably sleeved on the outside of the screw (2); A piston rod (3), wherein the piston rod (3) is fixedly connected to the nut (1); A bearing seat (4), the bearing seat (4) being sleeved on the screw rod (2), the front and rear ends of the bearing seat (4) being connected to first bearings (5) respectively in the axial direction, and the first bearing (5) being connected to the screw rod (2); A force sensor (6), wherein the force sensor (6) is sleeved on the screw rod (2), and the force sensor (6) is connected to the bearing seat (4).

2. The electric cylinder with built-in force sensor according to claim 1, characterized in that: Also includes: A second bearing (7), wherein the second bearing (7) is sleeved on the screw rod (2).

3. The electric cylinder with built-in force sensor according to claim 2, characterized in that: The first bearing (5) is a thrust cylindrical roller bearing, and the second bearing (7) is a cylindrical roller bearing.

4. The electric cylinder with built-in force sensor according to claim 1, characterized in that: A bearing pressure ring (8) is sleeved on the screw rod (2), a first step surface (9) is formed on the bearing pressure ring (8), a second step surface (10) is formed on the bearing seat (4), and the first bearing (5) is located between the first step surface (9) and the second step surface (10).

5. The electric cylinder with built-in force sensor according to claim 1, characterized in that: A third step surface (11) is formed on the screw rod (2), and a locking nut (12) is also sleeved on the screw rod (2). The locking nut (12) abuts against a bearing pressure ring (8) located at the rear side of the bearing seat (4), and the third step surface (11) abuts against a bearing pressure ring (8) located at the front side of the bearing seat (4).

6. The electric cylinder with built-in force sensor as claimed in claim 2, characterized in that: Also includes: A linear bearing (13) and a cylinder (14), wherein the cylinder (14) is sleeved on the outside of the piston rod (3), the linear bearing (13) is arranged between the piston rod (3) and the cylinder (14), and the linear bearing (13) is connected to the inner wall of the cylinder (14).

7. The electric cylinder with built-in force sensor according to claim 6, characterized in that: Also includes: A front end cover (15) is arranged at the front end of the cylinder (14), a limiting member (16) is fixedly arranged on the inner wall of the cylinder (14), and the front end cover (15) and the limiting member (16) are respectively abutted against two axial ends of the linear bearing (13).

8. The electric cylinder with built-in force sensor according to claim 6, characterized in that: Also includes: A base (17), wherein the base (17) is sleeved on the outer side of the screw rod (2), and the base (17) and the cylinder barrel (14) are connected to two axial ends of the force sensor (6).

9. The electric cylinder with built-in force sensor according to claim 8, characterized in that: The second bearing (7) is located between the base (17) and the screw rod (2).

10. The electric cylinder with built-in force sensor according to claim 1, characterized in that: Also includes: A driving assembly (20) and a reduction assembly (21), wherein the screw rod (2) is connected to the driving assembly (20) via the reduction assembly (21).

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