Double-working-condition electric cylinder based on reverse planetary roller screw

Abstract

The invention discloses a double-working-condition electric cylinder based on a reverse planetary roller screw, which belongs to the technical field of electric cylinders and comprises a cylinder body, a motor, a bearing assembly, a speed reducer, a clutch and a reverse planetary roller screw pair assembly. The motor, the bearing assembly, the speed reducer, the clutch and the reverse planetary roller screw pair assembly are arranged in the cylinder body; the reverse planetary roller screw assembly is rotationally connected to the inner wall of the cylinder body through a bearing assembly, and one end penetrates through the speed reducer, the clutch and the cylinder body and extends out of the cylinder body; the motor provides power for the reverse planetary roller screw pair assembly through the speed reducer; one side of the clutch is connected with the speed reducer, and the other side of the clutch is connected with the reverse planetary roller screw assembly; the speed reducer and the reverse planetary roller lead screw pair assembly are connected with the clutch to provide two working condition modes, and the clutch is used for switching between the two working condition modes. According to the invention, two working conditions of low-speed high load and high-speed low load can be realized so as to adapt to different application occasions.

Description

Technical Field

[0001] The invention belongs to the technical field of electric cylinders, and more specifically relates to a dual-working-mode electric cylinder based on a reverse planetary roller screw. Background Art

[0002] The electric cylinder is a common device that converts the rotary motion of the motor into the linear motion of the push rod. With the continuous expansion of its application field, some special occasions have put forward new requirements for the performance of the electric cylinder, such as higher operating stability, higher motion accuracy, more flexible motion mode, etc. In some application fields, the extension and retraction of the electric cylinder require different speeds and different thrusts. Existing electric cylinders such as CN111130263A propose an electric cylinder with a stator winding in the form of dual independent windings, which can still complete the corresponding functional actions under typical fault conditions; CN118554688A proposes a two-stage precision electric cylinder that realizes precision motion through a two-stage electric cylinder nesting solution. Both patents achieve different speeds by controlling the motor speed and achieve different thrusts by controlling the current. Due to the characteristics of the motor, its speed and current have certain limitations and cannot achieve a wide range of thrust changes.

[0003] Therefore, how to provide a dual-mode electric cylinder that can realize both low-speed and high-load working conditions and high-speed and low-load working conditions is a problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides a dual-working condition electric cylinder based on a reverse planetary roller screw, which adopts two different driving modes: directly driving the screw pair by a clutch selection motor and driving the screw pair through a reducer, to achieve two working conditions: low speed and high load and high speed and low load, so as to adapt to different application scenarios.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A dual-working-mode electric cylinder based on a reverse planetary roller screw comprises a cylinder body, a motor, a bearing assembly, a reducer, a clutch and a reverse planetary roller screw subassembly; the motor, bearing assembly, reducer, clutch and reverse planetary roller screw subassembly are arranged inside the cylinder body; the reverse planetary roller screw subassembly is rotatably connected to the inner wall of the cylinder body through the bearing assembly, one end of the reverse planetary roller screw subassembly passes through the reducer, the clutch and one end of the cylinder body and protrudes from the cylinder body to provide linear motion power to the outside; the motor provides power to the reverse planetary roller screw subassembly through the reducer; one side of the clutch is connected to the reducer, and the other side is connected to the reverse planetary roller screw subassembly; the connection between the reducer and the reverse planetary roller screw subassembly and the clutch provides two working modes, and the clutch is used to switch between the two working modes.

[0007] Furthermore, a front end cover and a rear end cover are respectively provided at the front and rear ends of the cylinder body; the front end cover and the rear end cover are both fixedly connected to the cylinder body by screws.

[0008] Furthermore, the motor rotor of the motor is rotatably connected to the inner wall of the cylinder body through the bearing assembly, and one end is fixedly connected to the reducer.

[0009] Furthermore, the reducer includes an input flange shaft, a reduction gear assembly and an output flange shaft; the reduction gear assembly is fixedly mounted on the inner wall of the cylinder body, one end of the inner wall of the ring is connected to the hollow input flange shaft, and the other end is connected to the hollow output flange shaft, so as to reduce the transmission speed; the input flange shaft is fixedly connected to the motor rotor.

[0010] Furthermore, the clutch comprises a driving assembly and a working assembly, wherein the driving assembly is connected to the cylinder body on the outside and connected to the working assembly on the inside; the working assembly is a circular ring structure, passing through the input flange shaft and the output flange shaft.

[0011] Furthermore, a plurality of external teeth are evenly fixed on the outer wall of the working component in the circumferential direction; a plurality of first through grooves of the same number as the external teeth are arranged along the circumferential direction of the inner wall of the input flange shaft; a plurality of second through grooves of the same number as the first through grooves are arranged along the circumferential direction of the inner wall of the output flange shaft; and the external teeth are respectively engaged with the first through grooves and the second through grooves during the movement of the working component.

[0012] Furthermore, a plurality of internal teeth having the same number as the external teeth are evenly fixed on the inner side wall of the working component in a circumferential direction; the nut of the reverse planetary roller screw subassembly is limited inside the cylinder body by the bearing assembly; a plurality of long grooves and third slot holes having the same number as the internal teeth and corresponding positions are provided on the outer wall of the nut; the internal teeth are respectively engaged with the long grooves and the third slot holes during the movement of the working component.

[0013] Further, when the outer teeth are embedded in the second through groove, the inner teeth are embedded in the long groove; when the outer teeth are embedded in the first through groove, the inner teeth are embedded in the third slot hole.

[0014] Furthermore, the annular groove between the long groove and the third slot hole is used as a switching groove or a neutral position.

[0015] The beneficial effects of the present invention are:

[0016] The present invention adopts a combination of a frameless torque motor and a reducer to reduce the axial and radial dimensions of the electric cylinder, making the structure more compact while being able to withstand extremely high loads; it adopts two different driving modes, namely, a clutch selecting motor directly driving the reverse planetary roller screw subassembly and a reducer driving the reverse planetary roller screw subassembly, to achieve two working conditions: low speed and high load and high speed and low load, thereby being able to adapt to different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0018] Figure 1 It is a front cross-sectional view of the present invention.

[0019] Figure 2 It is a schematic diagram of the structure of the working components under low speed and high load conditions of the present invention.

[0020] Figure 3 It is a schematic diagram of the structure of the working components under high-speed and low-load conditions of the present invention.

[0021] Figure 4 It is a schematic diagram of the connection structure of the working assembly, reducer and nut of the present invention.

[0022] Among them, in the figure:

[0023] 1-cylinder body; 11-rear end cover; 12-front end cover; 21-motor stator; 22-motor rotor; 23-encoder; 24-driver; 3-bearing assembly; 31-first bearing; 32-second bearing; 33-third bearing; 34-fourth bearing; 4-reducer; 41-input flange shaft; 411-first through groove; 42-reduction gear assembly; 43-output flange shaft; 431-second through groove; 5-clutch; 51-drive assembly; 52-working assembly; 521-external teeth; 522-internal teeth; 6-reverse planetary roller screw subassembly; 61-nut; 62-screw; 63-roller; 64-roller retaining ring; 65-circlip. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] Please see attached Figure 1-4 The present invention provides a dual-mode electric cylinder based on a reverse planetary roller screw, comprising a cylinder body 1, a motor, a bearing assembly 3, a reducer 4, a clutch 5 and a reverse planetary roller screw subassembly 6. The motor, the bearing assembly 3, the reducer 4, the clutch 5 and the reverse planetary roller screw subassembly 6 are arranged inside the cylinder body 1.

[0026] The front and rear ends of the cylinder body 1 are respectively provided with a front cover 12 and a rear cover 11; the front cover 12 and the rear cover 11 are both fixedly connected to the cylinder body 1 by screws.

[0027] The bearing 3 includes a first bearing 31 , a second bearing 32 , a third bearing 33 and a fourth bearing 34 .

[0028] The motor provides power to the reverse planetary roller screw assembly 6 through the reducer 4. The motor includes a motor stator 21, a motor rotor 22, an encoder 23 and a driver 24.

[0029] The motor stator 21 and the encoder 23 are coaxially fixed on the inner wall of the cylinder body 1; the motor rotor 22 is rotatably connected to the inner wall of the cylinder body 1 through the second bearing 32 and the third bearing 33; the encoder 23 is arranged on one side of the motor rotor 22; the driver 24 is arranged on the rear end cover 11; the connection relationship between the motor stator 21, the motor rotor 22, the encoder 23 and the driver 24 and their internal circuit layout are existing technologies and will not be repeated here.

[0030] The reducer 4 includes an input flange shaft 41, a reduction gear assembly 42 and an output flange shaft 43; the reduction gear assembly 42 is a prior art and will not be described in detail here. The reduction gear assembly 42 is fixedly mounted on the inner wall of the cylinder body 1, and one end of the inner wall of the ring is connected to the hollow input flange shaft 41, and the other end is connected to the hollow output flange shaft 43; the other end of the input flange shaft 41 is fixedly connected to the motor rotor 22; the motor rotor 22 transmits the motor power to the input flange shaft 41, and the input flange shaft 41 reduces the speed through the reduction gear assembly 42 and transmits it to the output flange shaft 43, and the generated high speed and low torque is converted into a low speed and high torque output.

[0031] One side of the clutch 5 is connected to the reducer 4, and the other side is connected to the reverse planetary roller screw subassembly 6; the reducer 4 provides two working modes, and the clutch 5 is used to switch between the two working modes. The clutch 5 includes a driving component 51 and a working component 52, the driving component 51 is connected to the cylinder 1 on the outside, and connected to the working component 52 on the inside; the connection drive between the driving component 51 and the working component 52 can be driven by electromagnet actuation and spring reset, or by pneumatic, hydraulic, screw, gear rack and other linear mechanical driving methods.

[0032] The working assembly 52 is a circular ring structure, and a plurality of external teeth 521 are evenly fixed on the outer wall in the circumferential direction, and a plurality of internal teeth 522 are evenly fixed on the inner wall in the circumferential direction; the external teeth 521 are arranged correspondingly with the internal teeth 522, and the number is the same. The input flange shaft 41 and the output flange shaft 43 are arranged along the circumferential direction of their inner walls with a plurality of first through grooves 411 and second through grooves 431; the first through grooves 411 and the second through grooves 431 are the same in number and arranged in corresponding positions. The positions and numbers of the first through grooves 411 and the second through grooves 431 are the same as the positions and numbers of the external teeth 521, so that when one end of the working assembly 52 provided with the external teeth 521 passes through the output flange shaft 43, the external teeth 521 can be embedded in the second through grooves 431, and also when one end of the working assembly 52 provided with the external teeth 521 passes through the input flange shaft 41 and the output flange shaft 43, the external teeth 521 can pass through the second through grooves 431 and be embedded in the first through grooves 411. Under the drive of the driving assembly 51 , the outer teeth 521 can be switched and embedded between the first through slot 411 and the second through slot 431 .

[0033] The two ends of the reverse planetary roller screw subassembly 6 are rotatably connected to the inner wall of the cylinder body 1 through the bearing assembly 3, and one end passes through the reducer 4, the clutch 5 and the cylinder body 1 and extends out of the cylinder body 1 to provide linear motion power to the outside. The reverse planetary roller screw subassembly 6 includes a nut 61, a screw 62, a roller 63, a roller retaining ring 64 and a retaining spring 65. The connection relationship and operating principle of each component are prior art and are not described here. The two ends of the outer side of the nut 61 are limited to the inside of the cylinder body 1 by the first bearing 31 and the fourth bearing 34.

[0034] The outer wall of the nut 61 is provided with a plurality of long slots 612 and third slots 611, which are equal in number and position to the inner teeth 522, and an annular groove 613 between the long slots 612 and the third slots 611; the working assembly 52 is sleeved on the nut 61, and its inner teeth 522 are embedded in the long slots 612, and can move along the long slots 612 toward the third slots 611. When the outer teeth 521 are embedded in the second through slots 431, the inner teeth 522 are embedded in the long slots 612; when the outer teeth 521 are embedded in the first through slots 411, the inner teeth 522 are embedded in the third slots 611. With the annular groove 613, when the outer teeth 521 switch between the first through slots 411 and the second through slots 431, the inner teeth 522 can perform a short speed switch. During the movement, the inner teeth 522 are located in the long slot 612 and in the three-slot hole 611 under two working conditions, so that the nut 61 has different rotation speeds respectively. The annular groove 613 can be used as a switching slot or as a neutral gear so that the motor power is not transmitted to the nut 61.

[0035] The inner teeth 522 and the outer teeth 521 are both provided with chamfers along the moving direction of the working unit 52 , so as to facilitate embedding in the first through groove 411 and the second through groove 431 , as well as the long groove 612 and the third slot 611 .

[0036] The operation process of the present invention is as follows: under the action of the driving unit 51, the working unit 52 moves axially. When the working unit 52 moves to the front end position, the outer teeth 521 are engaged with the first through groove 411, and the inner teeth 522 are engaged with the third slot 611. At this time, the power of the motor is output from the motor rotor 22 to the nut 61 through the input flange shaft 41 and the outer teeth 521, and the electric cylinder is in a high-speed and low-load working condition; when the working unit 52 moves to the rear end position, the outer teeth 521 are engaged with the second through groove 431, and the inner teeth 522 are engaged with the long groove 612. At this time, the power of the electric cylinder is output from the motor rotor 22 to the nut 61 through the output flange shaft 43 and the outer teeth 521, and the electric cylinder is in a low-speed and high-load working condition. The electric cylinder of the present invention can provide two working conditions to adapt to different application occasions.

[0037] The dual-working mode electric cylinder of the present invention also includes a controller, which is electrically connected to the encoder 23 to transmit the motor signal to the controller; the controller is electrically connected to the drive component 51 to control the drive component 51 to drive the working component 52 to move axially, thereby switching the working mode.

[0038] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0039] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A dual-mode electric cylinder based on a reverse planetary roller screw, characterized in that: The invention comprises a cylinder body (1), a motor, a bearing assembly (3), a reducer (4), a clutch (5) and a reverse planetary roller screw subassembly (6); the motor, the bearing assembly (3), the reducer (4), the clutch (5) and the reverse planetary roller screw subassembly (6) are arranged inside the cylinder body (1); the reverse planetary roller screw subassembly (6) is rotatably connected to the inner wall of the cylinder body (1) through the bearing assembly (3), and one end of the reverse planetary roller screw subassembly (6) passes through the reducer (4), the clutch (5) and the cylinder body (1). One end extends out of the cylinder body (1) to provide linear motion power to the outside; the motor provides power to the reverse planetary roller screw subassembly (6) through the reducer (4); one side of the clutch (5) is connected to the reducer (4), and the other side is connected to the reverse planetary roller screw subassembly (6); the connection between the reducer (4) and the reverse planetary roller screw subassembly (6) and the clutch (5) provides two working modes, and the clutch (5) is used to switch between the two working modes.

2. According to claim 1, a dual-mode electric cylinder based on a reverse planetary roller screw is characterized in that: The cylinder body (1) is provided with a front end cover (12) and a rear end cover (11) at the front and rear ends respectively; the front end cover (12) and the rear end cover (11) are both fixedly connected to the cylinder body (1) by screws.

3. According to claim 1, a dual-mode electric cylinder based on a reverse planetary roller screw is characterized in that: The motor rotor (22) of the motor is rotatably connected to the inner wall of the cylinder body (1) via the bearing assembly (3), and one end is fixedly connected to the reducer (4).

4. According to claim 3, a dual-mode electric cylinder based on a reverse planetary roller screw is characterized in that: The reducer (4) comprises an input flange shaft (41), a reduction gear assembly (42) and an output flange shaft (43); the reduction gear assembly (42) is fixedly arranged on the inner wall of the cylinder body (1), one end of the inner wall of the ring is connected to the hollow input flange shaft (41), and the other end is connected to the hollow output flange shaft (43), so as to reduce the transmission speed; the input flange shaft (41) is fixedly connected to the motor rotor (22).

5. According to claim 4, a dual-mode electric cylinder based on a reverse planetary roller screw is characterized in that: The clutch (5) comprises a driving assembly (51) and a working assembly (52); the driving assembly (51) is connected to the cylinder body (1) on the outside and connected to the working assembly (52) on the inside; the working assembly (52) is a circular ring structure and passes through the input flange shaft (41) and the output flange shaft (43).

6. According to claim 5, a dual-mode electric cylinder based on a reverse planetary roller screw is characterized in that: A plurality of external teeth (521) are evenly fixedly arranged on the outer wall of the working component (52); a plurality of first through grooves (411) whose number is the same as that of the external teeth (521) are arranged along the circumference of the inner wall of the input flange shaft (41); a plurality of second through grooves (431) whose number is the same as that of the first through grooves (411) are arranged along the circumference of the inner wall of the output flange shaft (43); and the external teeth (521) are respectively engaged with the first through grooves (411) and the second through grooves (431) during the movement of the working component (52).

7. A dual-mode electric cylinder based on a reverse planetary roller screw according to claim 6, characterized in that: A plurality of internal teeth (522) having the same number as the external teeth (521) are evenly fixedly arranged on the inner side wall of the working component (52); the nut (61) of the reverse planetary roller screw subassembly (6) is limited in the cylinder body (1) by the bearing assembly (3); a plurality of long grooves (612) and third slot holes (611) having the same number as the internal teeth (522) and corresponding positions are arranged on the outer wall of the nut (61); the internal teeth (522) are respectively engaged with the long grooves (612) and the third slot holes (611) during the movement of the working component (52).

8. The dual-mode electric cylinder based on a reverse planetary roller screw according to claim 7, characterized in that: When the outer teeth (521) are embedded in the second through groove (431), the inner teeth (522) are embedded in the long groove (612); when the outer teeth (521) are embedded in the first through groove (411), the inner teeth (522) are embedded in the third slot hole (611).

9. The dual-mode electric cylinder based on a reverse planetary roller screw according to claim 7, characterized in that: The annular groove (613) between the long groove (612) and the third slot hole (611) is used as a switching groove or a neutral position.

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