A kind of parent-child screw servo electric cylinder

Abstract

The present invention discloses a parent-child screw servo electric cylinder, which is provided with a spline shaft installed in a piston rod, and a spline sleeve which can slide relative to the spline shaft and rotate with the rotation of the spline shaft is arranged on the spline shaft, so that the piston rod and the spline sleeve are coaxially interference fit; an external thread is arranged on the outer wall of the piston rod, and an external nut member which is transmission-matched with the piston rod thread is arranged on the rod body provided with the external thread; and a first servo motor which is transmission-connected with the spline shaft and a second servo motor which is transmission-connected with the external nut member are arranged. When the second servo motor drives the external nut member to rotate and drive the piston rod to make a rapid linear motion, pressure is applied to the piston rod from the outer peripheral wall of the piston rod, and pressure is applied to the piston rod from the outer peripheral wall of the piston rod in cooperation with the first servo motor driving the spline sleeve to rotate, thereby increasing the torque on the piston rod while the piston rod makes a rapid linear motion, and realizing the pressurized motion of the electric cylinder at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of servo electric cylinders, and in particular to a parent-child screw servo electric cylinder. Background Art

[0002] Currently, commonly used servo electric cylinders include two types: single-screw servo electric cylinders and conventional servo electric cylinders. Single-screw servo electric cylinders use a single screw as the driving source; conventional servo electric cylinders use synchronous wheels and synchronous belts to drive the lead screw, so that the lead screw converts rotation into linear motion. With the development of industry, conventional electric cylinders cannot have two speed and force process requirements at the same time. In order to meet market demand, make electric cylinders more widely used, and effectively avoid some problems caused by conventional electric cylinders, it is necessary to study and improve servo electric cylinders. Summary of the invention

[0003] In view of the problems existing in the prior art, the main purpose of the present invention is to provide a parent-child screw servo electric cylinder, so that the servo electric cylinder can achieve both rapid movement and boosted movement.

[0004] To achieve the above-mentioned purpose, the parent-child screw servo electric cylinder proposed in the present invention comprises a first servo motor, a piston rod, a second servo motor and an outer nut member;

[0005] A spline shaft is arranged inside the piston rod, and a spline sleeve is arranged on the spline shaft, which can slide relative to the spline shaft and rotate with the rotation of the spline shaft, and the piston rod and the spline sleeve are coaxially interference fit;

[0006] The outer wall of the piston rod is provided with an external thread, and the external nut is sleeved on the rod body of the piston rod provided with the external thread and cooperates with the piston rod through thread transmission;

[0007] The first servo motor is drivingly connected to the spline shaft, and the second servo motor is drivingly connected to the outer nut member;

[0008] In the rapid motion state, the second servo motor drives the outer nut member to rotate, and the outer nut member cooperates with the threaded transmission of the piston rod to drive the piston rod to perform rotational motion and rapid linear motion along the axial direction of the piston rod;

[0009] In the boost motion state, the first servo motor and the second servo motor operate simultaneously, and the second servo motor drives the outer nut to rotate to apply pressure to the piston rod from the outer circumferential wall of the piston rod, and the first servo motor drives the spline sleeve to rotate to apply pressure to the piston rod from the outer circumferential wall of the piston rod, thereby increasing the torque applied to the piston rod while the piston rod makes rapid linear motion, thereby completing the boost motion of the electric cylinder.

[0010] Optionally, the spline shaft is provided with a spline groove arranged along its axial direction, and the spline sleeve is provided with a rolling element, and the rolling element is partially stuck in the spline groove and can roll in the spline groove.

[0011] Optionally, the first servo motor is drivingly connected to the spline shaft via a transmission member.

[0012] Optionally, the transmission member is a shaft gear, the shaft body of the shaft gear is coaxially connected to the spline shaft, and the gear body is meshed and transmission-coordinated with a gear provided on the output shaft of the first servo motor.

[0013] Optionally, the transmission member is a first synchronous belt, and a first synchronous pulley and a second synchronous pulley are respectively provided on the spline shaft and the output shaft of the first servo motor, and the first synchronous pulley and the second synchronous pulley are connected through the first synchronous belt transmission.

[0014] Optionally, teeth are provided on the outer peripheral wall of the outer nut member, and a transmission gear is provided on the output shaft of the second servo motor, and the transmission gear is meshed and transmission-coordinated with the teeth of the outer nut member.

[0015] Optionally, a third synchronous pulley is sleeved on the outer nut member, a fourth synchronous pulley is disposed on the output shaft of the second servo motor, and the third synchronous pulley and the fourth synchronous pulley are connected via a second synchronous belt transmission.

[0016] Optionally, two fixing seats are further included, which are located on both sides of the outer nut member and sleeved on the piston rod, and a plane bearing is provided between the fixing seat and the outer nut member.

[0017] Optionally, two guide sleeves are further included, and the two guide sleeves are sleeved on the piston rod and coaxially slidably matched with the piston rod.

[0018] The present invention has a spline shaft installed in the piston rod, and a spline sleeve is provided on the spline shaft, which can slide relative to the spline shaft and rotate with the rotation of the spline shaft, so that the piston rod and the spline sleeve are coaxially interference fit; an external thread is provided on the outer wall of the piston rod, and an external nut member that is transmission-matched with the piston rod thread is provided on the rod body provided with the external thread; and a first servo motor transmission-connected to the spline shaft and a second servo motor transmission-connected to the external nut member are provided.

[0019] In the rapid motion state, the second servo motor drives the outer nut member to rotate, and the outer nut member cooperates with the threaded transmission of the piston rod to drive the piston rod to perform rotational motion and rapid linear motion along the axial direction of the piston rod;

[0020] In the boost motion state, the first servo motor and the second servo motor operate simultaneously, and the second servo motor drives the outer nut to rotate to apply pressure to the piston rod from the outer circumferential wall of the piston rod, and the first servo motor drives the spline sleeve to rotate to apply pressure to the piston rod from the outer circumferential wall of the piston rod, thereby increasing the torque applied to the piston rod while the piston rod makes rapid linear motion, thereby completing the boost motion of the electric cylinder.

[0021] By adopting the mother-and-child screw servo electric cylinder provided by the present invention, it is possible to realize both rapid movement and pressurized movement, thereby adapting to die-casting equipment with high requirements on force and speed, and providing a basis for servo electric cylinders to replace hydraulic cylinders of traditional die-casting equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of the parent-child screw servo electric cylinder of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the accompanying 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 making creative work are within the scope of protection of the present invention.

[0024] Please refer to the instruction manual Figure 1 In an embodiment of the present invention, a parent-child screw servo electric cylinder is proposed. The servo electric cylinder includes a first servo motor 1, a piston rod 2, an outer nut member 4 and a second servo motor 5.

[0025] A hollow area is arranged at the center of the piston rod 2, in which a spline shaft 3 is arranged coaxially with the piston rod 2, and a spline sleeve 31 is arranged on the spline shaft 3, which can slide relative to the spline shaft 3 and rotate with the rotation of the spline shaft 3. The inner wall of the piston rod 2 and the outer wall of the spline sleeve 31 are tightly assembled together by interference fit.

[0026] It should be noted that the spline pair formed by the spline shaft 3 and the spline sleeve 31 used in this embodiment may also adopt an existing ball spline pair.

[0027] The outer wall of the piston rod 2 is processed with an external thread 2a, and the external nut 4 is sleeved on the rod body of the piston rod 2 provided with the external thread 2a and cooperates with the piston rod 2 through thread transmission.

[0028] The first servo motor 1 is drivingly connected to the spline shaft 3 , and the second servo motor 5 is drivingly connected to the outer nut member 4 .

[0029] In this embodiment, the servo electric cylinder further includes two fixing seats 8, which are located on both sides of the outer nut member 4 and sleeved on the piston rod 2. The body of the fixing seat 8 is fixedly connected to the inner wall of the cylinder body of the servo electric cylinder (not shown), and a plane bearing 7 is provided between the fixing seat 8 and the outer nut member 4. In this way, the outer nut member 4 is fixed to prevent the outer nut member 4 from axial displacement.

[0030] In this embodiment, two guide sleeves 6 coaxially slidingly matched with the piston rod 2 are sleeved on the piston rod 2, and the two guide sleeves 6 are fixedly connected to the inner wall of the cylinder body of the servo electric cylinder, thereby maintaining the stability of the rapid linear motion of the piston rod 2.

[0031] When the piston rod 2 of the electric cylinder needs to move quickly, the second servo motor 5 drives the outer nut 4 to rotate, and the threaded transmission of the outer nut 4 and the piston rod 2 drives the piston rod 2 to rotate and simultaneously make rapid linear motion along the axial direction of the piston rod 2.

[0032] When the piston rod 2 of the electric cylinder needs to move quickly and provide sufficient operating force at the same time, that is, the piston rod 2 moves quickly and performs boosting movement. At this time, the first servo motor 1 and the second servo motor 5 act simultaneously, and the second servo motor 5 drives the outer nut member 4 to rotate and drive the piston rod 2 to make rapid linear movement and apply pressure to the piston rod 2 from the outer peripheral wall of the piston rod 2, and cooperates with the first servo motor 1 to drive the spline sleeve 31 to rotate and apply pressure to the piston rod 2 from the outer peripheral wall of the piston rod 2, thereby increasing the torque and pressure area of ​​the piston rod 2, and then when the piston rod 2 reaches rapid movement, the first servo motor 1 increases the operating force of the piston rod 2, so that the electric cylinder can complete both rapid movement and boosting movement.

[0033] In this way, by adopting the parent-screw servo electric cylinder provided by the above solution, the electric cylinder can achieve both rapid movement and pressurized movement, thereby adapting to die-casting equipment with high requirements for force and speed, and providing a basis for servo electric cylinders to replace hydraulic cylinders of traditional die-casting equipment.

[0034] Moreover, by controlling the rotation of the first servo motor 1 and the second servo motor 5, the piston rod 2 can also make linear motion with different forces and speeds, wherein the running speed of the piston rod 2 is completed by the second servo motor 5, and the running force of the piston rod 2 is completed by the first servo motor 1 and the second servo motor 5, so that it can be applied to die-casting equipment to replace the hydraulic cylinder of traditional press-fitting equipment.

[0035] Moreover, the parent-child screw servo electric cylinder provided by the present invention only needs to process the external thread 2a on the outer peripheral wall of the original piston rod 2, and set an external nut part 4 on the rod body with the external thread 2a, and set a second servo motor 5 to drive the external nut part 4 to rotate, and then cooperate with the internal spline pair of the piston to realize the pressurization of the piston rod 2. The structure is simple and easy to implement.

[0036] Optionally, in this embodiment, the spline shaft 3 is provided with a spline groove (not shown) arranged along its axial direction, and a rolling element (not shown) is provided in the spline sleeve 31, and the rolling element is partially stuck in the spline groove and can roll in the spline groove. Thus, when the spline shaft 3 rotates, the spline sleeve 31 can be driven to rotate together, and when the spline shaft 3 does not rotate, the spline sleeve 31 can also slide relative to the spline shaft 3.

[0037] Alternatively, if Figure 1 As shown, in this embodiment, the output shaft of the first servo motor 1 is connected to the spline shaft 3 through a transmission member 32. One end of the spline shaft 3 extends outward along its axial direction and protrudes from the piston rod 2, and the transmission member 32 is coaxially arranged on the protruding portion of the piston rod 2. When the output shaft of the first servo motor 1 rotates, the spline shaft 3 is driven to rotate through the transmission member 32, and pressure is applied to the piston rod 2 from the inner side wall of the piston rod 2, and the outer nut member 4 cooperates to increase the operating force of the piston rod 2.

[0038] Specifically, the transmission member 32 is a shaft gear, the shaft body of the shaft gear is coaxially connected to the spline shaft 3 , and the gear body is meshed and transmission-matched with a gear provided on the output shaft of the first servo motor 1 .

[0039] In some other embodiments, a synchronous belt may also be used as a transmission member between the first servo motor 1 and the spline shaft 3. When the synchronous belt is used as the transmission member, a first synchronous pulley and a second synchronous pulley are respectively provided on the spline shaft 3 and the output shaft of the first servo motor 1, and a first synchronous belt is provided between the first synchronous pulley and the second synchronous pulley, thereby realizing transmission cooperation between the first servo motor 1 and the spline shaft 3 through the first synchronous belt.

[0040] Optionally, in this embodiment, teeth are provided on the outer peripheral wall of the outer nut member 4, and a transmission gear is provided on the output shaft of the second servo motor 5, thereby, the transmission cooperation between the second servo motor 5 and the outer nut member 4 is achieved by meshing between the transmission gear and the teeth of the outer nut member 4.

[0041] In some other embodiments, a synchronous belt may be used as a transmission connection between the second servo motor 5 and the outer nut member 4. When the synchronous belt is used as a transmission member, a third synchronous pulley is sleeved on the outer nut member 4, a fourth synchronous pulley is provided on the output shaft of the second servo motor 5, and a second synchronous belt is provided between the third synchronous pulley and the fourth synchronous pulley, thereby realizing the transmission cooperation between the second servo motor 5 and the outer nut member 4 through the second synchronous belt.

[0042] In addition, a synchronous pulley groove may be provided on the outer peripheral wall of the outer nut member 4 to avoid the tediousness of providing a synchronous pulley on the outer nut member 4 .

[0043] The above description is only a preferred embodiment of the present invention and is not intended to be construed as limiting the present invention. Any minor modifications, equivalent substitutions and improvements made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A parent-child screw servo electric cylinder, comprising a first servo motor and a piston rod; characterized in that: Also includes a second servo motor and an outer nut member; A spline shaft is arranged inside the piston rod, and a spline sleeve is arranged on the spline shaft, which can slide relative to the spline shaft and rotate with the rotation of the spline shaft, and the piston rod and the spline sleeve are coaxially interference fit; The outer wall of the piston rod is provided with an external thread, and the external nut is sleeved on the rod body of the piston rod provided with the external thread and cooperates with the piston rod through thread transmission; The first servo motor is drivingly connected to the spline shaft, and the second servo motor is drivingly connected to the outer nut member; In the rapid motion state, the second servo motor drives the outer nut member to rotate, and the outer nut member cooperates with the threaded transmission of the piston rod to drive the piston rod to perform rotational motion and rapid linear motion along the axial direction of the piston rod; In the boost motion state, the first servo motor and the second servo motor operate simultaneously, and the second servo motor drives the outer nut to rotate to apply pressure to the piston rod from the outer circumferential wall of the piston rod, and the first servo motor drives the spline sleeve to rotate to apply pressure to the piston rod from the outer circumferential wall of the piston rod, thereby increasing the torque applied to the piston rod while the piston rod makes rapid linear motion, thereby completing the boost motion of the electric cylinder.

2. The parent-child screw servo electric cylinder according to claim 1, characterized in that: The spline shaft is provided with a spline groove arranged along its axial direction, and the spline sleeve is provided with a rolling element. The rolling element is partially stuck in the spline groove and can roll in the spline groove.

3. The parent-child screw servo electric cylinder according to claim 1, characterized in that: The first servo motor is drivingly connected to the spline shaft via a transmission member.

4. The parent-child screw servo electric cylinder according to claim 3, characterized in that: The transmission member is a shaft gear, the shaft body of the shaft gear is coaxially connected to the spline shaft, and the gear body is meshed and transmission-matched with a gear arranged on the output shaft of the first servo motor.

5. The parent-child screw servo electric cylinder according to claim 3, characterized in that: The transmission member is a first synchronous belt. A first synchronous pulley and a second synchronous pulley are respectively arranged on the spline shaft and the output shaft of the first servo motor. The first synchronous pulley and the second synchronous pulley are connected through the first synchronous belt transmission.

6. The parent-child screw servo electric cylinder according to claim 1, characterized in that: The outer peripheral wall of the outer nut member is provided with teeth, and the output shaft of the second servo motor is provided with a transmission gear, and the transmission gear is meshed and transmission-coordinated with the teeth of the outer nut member.

7. The parent-child screw servo electric cylinder according to claim 1, characterized in that: A third synchronous belt pulley is sleeved on the outer nut member, a fourth synchronous belt pulley is arranged on the output shaft of the second servo motor, and the third synchronous belt pulley and the fourth synchronous belt pulley are connected through a second synchronous belt transmission.

8. The parent-child screw servo electric cylinder according to any one of claims 1 to 7, characterized in that: It also includes two fixing seats, which are located on both sides of the outer nut member and sleeved on the piston rod. A plane bearing is provided between the fixing seat and the outer nut member.

9. The parent-child screw servo electric cylinder according to claim 8, characterized in that: It also includes two guide sleeves, which are sleeved on the piston rod and coaxially slidably matched with the piston rod.

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