A linear drive device

Abstract

The utility model provides a kind of linear drive device, including hollow servo motor, screw rod, nut assembly, first bearing and second bearing, hollow servo motor includes shell, stator, rotor and hollow output shaft, rotor fixed sleeve is set in the outer peripheral wall of hollow output shaft, hollow output shaft output end is fixedly connected with nut assembly, nut assembly sleeve is set in the outer peripheral wall of screw rod and is connected with screw rod thread, the inner ring of first bearing is fixedly sleeved in the outer peripheral wall of hollow output shaft, the outer ring of first bearing is fixedly connected with shell, the inner ring of second bearing is fixedly sleeved in the outer peripheral wall of nut assembly, the outer ring of second bearing is fixedly connected with shell, this structure makes the axial linear motion of screw rod in the hole of hollow output shaft more stable, screw rod cannot appear motion deviation under the restriction of the hole of hollow output shaft, and does not need shaft coupling and bearing seat, entire structure is simple and stable, reliable in operation, and reduce production cost.

Description

Technical Field

[0001] This utility model belongs to the field of precision press-fitting technology, and in particular relates to a linear drive device. Background Technology

[0002] Traditional linear drive devices used in the precision press-fitting industry often employ nut and lead screw assemblies to convert the rotary motion of a servo motor into linear motion. However, the output shaft of the servo motor in this type of device is a solid shaft, requiring a coupling to connect the output shaft of the servo motor to the lead screw. This makes installation cumbersome and costly, and the rigidity is not high. Bearing housings are needed to make the linear motion of the lead screw more stable, which further increases the installation difficulty and production cost. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a linear drive device that can drive the linear motion of the lead screw with a simpler and more stable structure, and greatly reduce production.

[0004] To achieve the above objectives, the technical solution adopted in this application embodiment is: a linear drive device, including a hollow servo motor, a lead screw, a nut assembly, a first bearing, and a second bearing. The hollow servo motor includes a housing, a stator, a rotor, and a hollow output shaft arranged sequentially from the outside to the inside. The rotor is fixedly sleeved on the outer peripheral wall of the hollow output shaft. The output end of the hollow output shaft is fixedly connected to one end of the nut assembly. The nut assembly is sleeved on the outer peripheral wall of the lead screw and threadedly connected to the lead screw. The nut assembly is used to drive the lead screw to move linearly along its axial direction in the inner hole of the hollow output shaft. The inner ring of the first bearing is fixedly sleeved on the outer peripheral wall of the hollow output shaft, and the outer ring of the first bearing is fixedly connected to the housing. The inner ring of the second bearing is fixedly sleeved on the outer peripheral wall of the nut assembly, and the outer ring of the second bearing is fixedly connected to the housing.

[0005] Specifically, both the first and second bearings are single-row tapered roller bearings, and the contact angle α of the single-row tapered roller bearing is 10-29°.

[0006] Specifically, the nut assembly includes a nut and a connector. The connector is sleeved on the outer peripheral wall of the nut and has an interference fit with the outer peripheral wall of the nut. One end of the connector adjacent to the hollow output shaft is fixedly connected to the output end of the hollow output shaft. A boss is provided on the outer peripheral wall of the end of the nut away from the hollow output shaft. The end of the connector away from the hollow output shaft is fixedly connected to the boss by a screw.

[0007] Specifically, the nut assembly includes a nut, a connector, and a bolt. The outer peripheral wall of the connector has a threaded hole that is radially arranged and mates with the bolt. The connector is sleeved on the outer peripheral wall of the nut. The bolt is threadedly connected to the threaded hole to fix the connector to the outer peripheral wall of the nut. A boss is provided on the outer peripheral wall of the end of the nut away from the hollow output shaft. The end of the connector adjacent to the hollow output shaft is fixedly connected to the output end of the hollow output shaft. The end of the connector away from the hollow output shaft is connected to the boss by a screw.

[0008] Specifically, the nut assembly includes a nut and a connector. The outer peripheral wall of the end of the nut away from the hollow output shaft is provided with a boss, which is elliptical, racetrack-shaped, or polygonal. The end of the connector adjacent to the hollow output shaft is fixedly connected to the output end of the hollow output shaft. The end of the connector away from the hollow output shaft is provided with a groove that engages with the boss. The connector is sleeved on the outer peripheral wall of the nut.

[0009] Specifically, the inner hole of the hollow output shaft is a through hole.

[0010] Specifically, the lead screw is cylindrical.

[0011] Specifically, a first snap-fit ​​portion is provided on the end face of the output end of the hollow output shaft, and a second snap-fit ​​portion is provided on the end face of the nut assembly adjacent to one end of the hollow output shaft.

[0012] This invention uses a connector to fix the hollow output shaft and nut assembly together, and then uses a first bearing and a second bearing to provide support for the combination of the hollow output shaft and nut assembly. This makes the axial linear movement of the lead screw in the inner hole of the hollow output shaft more stable. The lead screw will not have any movement deviation under the restriction of the inner hole of the hollow output shaft. It does not require additional couplings and bearing seats. The whole structure is simple and stable, reliable in operation, and reduces production costs. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view of a linear drive device provided in an embodiment of this utility model.

[0014] Figure 2 This is an overall structural diagram of a linear drive device provided in an embodiment of the present invention.

[0015] Figure 3 This is an overall structural diagram of a linear drive device provided in another embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0017] like Figure 1 As shown in the figure, a linear drive device according to an embodiment of the present invention includes a hollow servo motor 1, a lead screw 2, a nut assembly 3, a first bearing 4, and a second bearing 5. The hollow servo motor 1 includes a housing 11, a stator 12, a rotor 13, and a hollow output shaft 14 arranged sequentially from the outside to the inside. The rotor 13 is fixedly sleeved on the outer peripheral wall of the hollow output shaft 14. The output end of the hollow output shaft 14 is fixedly connected to one end of the nut assembly 3. The nut assembly 3 is sleeved on the outer peripheral wall of the lead screw 2 and threadedly connected to the lead screw 2. The nut assembly 3 is used to drive the lead screw 2 to move linearly along its axial direction in the inner hole of the hollow output shaft 14. The inner ring of the first bearing 4 is fixedly sleeved on the outer peripheral wall of the hollow output shaft 14, and the outer ring of the first bearing 4 is fixedly connected to the housing 11. The inner ring of the second bearing 5 is fixedly sleeved on the outer peripheral wall of the nut assembly 3, and the outer ring of the second bearing 5 is fixedly connected to the housing 11.

[0018] During operation, the rotor 13 of the hollow servo motor 1 drives the hollow output shaft 14 to rotate together. The hollow output shaft 14 drives the nut assembly 3 to rotate. The nut assembly 3 drives the lead screw 2, which is threadedly connected to it, to move axially in the inner hole of the hollow output shaft 14. This configuration is simple in structure and reliable in operation. Furthermore, by setting the first bearing 4 and the second bearing 5 on the housing 11 to provide support for the combination of the hollow output shaft 14 and the nut assembly 3, the axial linear movement of the lead screw 2 in the inner hole of the hollow output shaft 14 is more stable. The lead screw 2 will not have any movement deviation under the constraint of the inner hole of the hollow output shaft 14, and no additional couplings and bearing seats are required. The entire structure is simple and stable, reducing production costs.

[0019] The linear drive device of this utility model adopts a direct drive and direct connection method, which has a simple structure, high precision, improves assembly efficiency, reduces production costs, and saves space.

[0020] Specifically, the first bearing 4 and the second bearing 5 are both single-row tapered roller bearings. The contact angle α of the single-row tapered roller bearing is 10-29°. This setting allows the single-row tapered roller bearing with extremely high rigidity to provide greater support for the combination of the hollow output shaft 14 and the lead screw nut 3, thereby making the linear motion of the lead screw 2 in the inner hole of the hollow output shaft 14 more stable.

[0021] Specifically, such as Figure 2As shown, the nut assembly 3 includes a nut 31 and a connector 32. The connector 32 is sleeved on the outer peripheral wall of the nut 31 and is interference-fitted with the outer peripheral wall of the nut 31. One end of the connector 32 adjacent to the hollow output shaft 14 is fixedly connected to the output end of the hollow output shaft 14. A boss 311 is provided on the outer peripheral wall of the end of the nut 31 away from the hollow output shaft 14. The end of the connector 32 away from the hollow output shaft 14 is connected to the boss 311 by a screw. With this arrangement, the nut 31 can be rotated more stably by the connector 32, and when the nut 31 is long, it is convenient for the hollow output shaft 14 to be fastened to the nut 31 by the connector 32.

[0022] Specifically, such as Figure 2 As shown, the nut assembly 3 includes a nut 31, a connector 32, and a bolt (not shown). The outer peripheral wall of the connector 32 is provided with a screw hole 321 that mates with the bolt (not shown). The connector 32 is sleeved on the outer peripheral wall of the nut 31. The bolt is threadedly connected to the screw hole 321 to fix the connector 32 to the outer peripheral wall of the nut 31. The outer peripheral wall of the end of the nut 31 away from the hollow output shaft 14 is provided with a boss 311. The end of the connector 32 adjacent to the hollow output shaft 14 is fixedly connected to the output end of the hollow output shaft 14. The end of the connector 32 away from the hollow output shaft 14 is connected to the boss 311 by a screw. This arrangement allows the connector 32 to drive the nut 31 to rotate more stably, and when the nut 31 is long, it is convenient for the hollow output shaft 14 to be fastened to the nut 31 through the connector 32.

[0023] Specifically, such as Figure 3 As shown, the nut assembly 3 includes a nut 31 and a connector 32. A boss 311, which can be elliptical, racetrack-shaped, or polygonal, is provided on the outer peripheral wall of the end of the nut 31 furthest from the hollow output shaft 14. One end of the connector 32 is fixedly connected to the output end of the hollow output shaft 14, and the other end of the connector 32 has a groove 322 that engages with the boss 311. The connector 32 is fitted onto the outer peripheral wall of the nut 31. This arrangement allows the connector 32 to more stably drive the nut 31 to rotate, and when the nut 31 is long, it facilitates the fastening of the hollow output shaft 14 to the nut 31 via the connector 32.

[0024] Specifically, the inner hole of the hollow output shaft 14 is a through hole. This design allows for sufficient clearance for the lead screw 2 when its linear displacement is large.

[0025] Specifically, lead screw 2 is cylindrical, which facilitates heat dissipation.

[0026] Specifically, a first snap-fit ​​portion (not shown) is provided on the end face of the output end of the hollow output shaft 14, and a second snap-fit ​​portion (not shown) is provided on the end face of the nut assembly 3 adjacent to one end of the hollow output shaft 14. This arrangement facilitates the fixed connection and assembly of the hollow output shaft 14 and the lead screw nut 3.

[0027] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A linear drive device, comprising a hollow servo motor (1), a lead screw (2), a nut assembly (3), a first bearing (4), and a second bearing (5), characterized in that: The hollow servo motor (1) includes a housing (11), a stator (12), a rotor (13), and a hollow output shaft (14) arranged sequentially from the outside to the inside. The rotor (13) is fixedly sleeved on the outer peripheral wall of the hollow output shaft (14). The output end of the hollow output shaft (14) is fixedly connected to one end of the nut assembly (3). The nut assembly (3) is sleeved on the outer peripheral wall of the lead screw (2) and threadedly connected to the lead screw (2). The nut assembly (3) is used to drive the lead screw (2) to move linearly along its axial direction in the inner hole of the hollow output shaft (14). The inner ring of the first bearing (4) is fixedly sleeved on the outer peripheral wall of the hollow output shaft (14). The outer ring of the first bearing (4) is fixedly connected to the housing (11). The inner ring of the second bearing (5) is fixedly sleeved on the outer peripheral wall of the nut assembly (3). The outer ring of the second bearing (5) is fixedly connected to the housing (11).

2. The linear drive device according to claim 1, characterized in that: The first bearing (4) and the second bearing (5) are both single-row tapered roller bearings, and the contact angle α of the single-row tapered roller bearing is 10-29°.

3. A linear drive device according to claim 1, characterized in that: The nut assembly (3) includes a nut (31) and a connector (32). The connector (32) is sleeved on the outer peripheral wall of the nut (31) and has an interference fit with the outer peripheral wall of the nut (31). One end of the connector (32) adjacent to the hollow output shaft (14) is fixedly connected to the output end of the hollow output shaft (14). A boss (311) is provided on the outer peripheral wall of the end of the nut (31) away from the hollow output shaft (14). The end of the connector (32) away from the hollow output shaft (14) is fixedly connected to the boss (311) by screws.

4. A linear drive device according to claim 1, characterized in that: The nut assembly (3) includes a nut (31), a connector (32), and a bolt. The outer peripheral wall of the connector (32) has a threaded hole (321) arranged radially therein and cooperating with the bolt. The connector (32) is sleeved on the outer peripheral wall of the nut (31). The bolt is threaded to the threaded hole (321) to fix the connector (32) on the outer peripheral wall of the nut (31). A boss (311) is provided on the outer peripheral wall of the end of the nut (31) away from the hollow output shaft (14). The end of the connector (32) adjacent to the hollow output shaft (14) is fixedly connected to the output end of the hollow output shaft (14). The end of the connector (32) away from the hollow output shaft (14) is connected to the boss (311) by a screw.

5. A linear drive device according to claim 1, characterized in that: The nut assembly (3) includes a nut (31) and a connector (32). The outer peripheral wall of the nut (31) away from the hollow output shaft (14) is provided with a boss (311). The boss (311) is elliptical, racetrack-shaped or polygonal. The end of the connector (32) adjacent to the hollow output shaft (14) is fixedly connected to the output end of the hollow output shaft (14). The end of the connector (32) away from the hollow output shaft (14) is provided with a slot (322) that engages with the boss (311). The connector (32) is sleeved on the outer peripheral wall of the nut (31).

6. A linear drive device according to claim 1, characterized in that: The inner hole of the hollow output shaft (14) is a through hole.

7. A linear drive device according to claim 1, characterized in that: The lead screw (2) is cylindrical.

8. A linear drive device according to claim 1, characterized in that: The output end of the hollow output shaft (14) is provided with a first snap-fit ​​portion, and the nut assembly (3) is provided with a second snap-fit ​​portion on the end face of one end adjacent to the hollow output shaft (14).

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