High speed nut rotation feed lead screw device

Abstract

The present invention discloses a high-speed nut rotating feed lead screw device including a lead screw, a lead screw nut, a bearing unit and a driving unit, the lead screw is fixed to a machine tool through a lead screw base, the bearing unit includes a bearing inner fixed sleeve, a bearing outer fixed sleeve and a bearing assembly mounted therebetween, one end of the bearing inner fixed sleeve is fixedly connected to one end of the lead screw nut and the other end is fixedly connected to the driving unit. The lead screw nut is installed on the lead screw, the driving unit includes a first pulley, a second pulley, a timing belt and a driving motor, the first pulley is connected to the driving motor, the second pulley is fitted on the lead screw and connected to the bearing inner fixed sleeve, and the first pulley and the second pulley are connected by a timing belt. The high-speed nut rotating feed lead screw device disclosed in the present invention has the advantages of simple structure, small volume, easy heat dissipation, fast operating speed, etc.

Description

[Technical field]

[0001] The present invention relates to the feed drive technical field of a numerically controlled machine tool, and in particular to a high-speed nut rotation feed lead screw device. [Background technology]

[0002] In the field of numerically controlled machine tools, the lead screw drive is a design structure that is often adopted, especially the feed motion of the slide table or spindle of the machine tool. However, the conventional lead screw drive generally uses a drive motor to connect to the lead screw, which drives the lead screw to rotate, and the lead screw nut is fixedly connected to the moving member, and under the rotation of the lead screw, the lead screw nut is driven to move along a straight line to realize the driving of the moving member. However, the conventional lead screw drive has the following disadvantages: The volume and mass of the lead screw are large, and therefore its inertia is also large. When driving the lead screw to rotate, a drive motor with high output is required, which increases the volume and cost of the entire drive. At the same time, the conventional lead screw drive needs to install a bearing unit outside the lead screw nut, which increases the radial dimension of the lead screw nut assembly and increases the volume of the entire lead screw drive. At the same time, because the bearing unit is installed outside the lead screw nut, the heat generated between the lead screw nut and the lead screw is difficult to dissipate, which affects the performance and service life of the lead screw nut. Summary of the Invention

[0003] SUMMARY OF THE PRESENT DISCLOSURE In order to address the above-mentioned problems, the present invention provides a high-speed nut rotation feed lead screw device.

[0004] The technical solutions adopted in the present invention are as follows:

[0005] A high-speed nut rotating feed lead screw device including a lead screw, a lead screw nut, a bearing unit and a drive unit, The lead screw is fixed to a machine tool via a lead screw base, the bearing unit includes an inner-bearing fixed sleeve, an outer-bearing fixed sleeve, and a bearing assembly, the outer-bearing fixed sleeve is fitted in the inner-bearing fixed sleeve, a bearing mounting space is formed between the outer-bearing fixed sleeve and the inner-bearing fixed sleeve, the bearing assembly is mounted in the bearing mounting space, one end of the inner-bearing fixed sleeve is a lead screw nut connecting end for fixing and connecting to one end of a lead screw nut, and the other end of the inner-bearing fixed sleeve is a drive unit connecting end for fixing and connecting to a drive unit, The lead screw nut is installed on the lead screw, and one end of the lead screw nut is fixedly connected to the lead screw nut connecting end of the bearing inner fixing sleeve; The drive unit includes a first pulley, a second pulley, a timing belt and a drive motor, the first pulley is connected to the drive motor, the second pulley is fitted to the lead screw and fixedly connected to the drive unit connection end of the bearing inner fixed sleeve, and the first pulley and the second pulley are connected via a timing belt.

[0006] Furthermore, a bearing seal ring is provided at one end adjacent to the lead screw nut connection end between the bearing inner fixed sleeve and the bearing outer fixed sleeve.

[0007] Furthermore, the bearing outer fixed sleeve is further provided with an oil injection passage communicating with the bearing seal ring.

[0008] Furthermore, a torque limiter is further provided between the drive motor and the first pulley.

[0009] Further, the bearing assembly includes two sets of symmetrically mounted angular contact ball bearings, each set of angular contact ball bearings including at least one angular contact ball bearing.

[0010] Furthermore, the sleeve fixed in the bearing has a stepped shaft sleeve structure, and one end of the sleeve fixed in the bearing adjacent to the drive unit connection end is provided with a male thread, and the bearing assembly is fixed to the sleeve fixed in the bearing by a lock nut.

[0011] The bearing further includes a pressing cover, which is fixedly connected by screws to one end of the slide table adjacent to the drive unit connection end and to one end of the bearing outer fixed sleeve adjacent to the drive unit connection end.

[0012] Furthermore, the lead screw is further provided with a cooling passage arranged along the axial direction of the lead screw.

[0013] Compared with the prior art, the beneficial effects of the high-speed nut rotating feed lead screw device disclosed in the present invention are as follows: In the lead screw device disclosed in the present invention, the driving unit directly drives and rotates the lead screw nut, and the lead screw nut drives and moves the slide table, so that the volume of the lead screw nut is small, the weight is light, and the inertia is small, so that a driving motor with a small output can be adopted to drive it, and the volume and cost of the device are reduced. At the same time, the motion inertia of the entire device is small, so that the high-speed rotating feed of the lead screw nut can be realized. In addition, since the lead screw nut and the bearing unit are arranged along the axial direction of the lead screw, the overall outer diameter of the lead screw nut and the bearing unit is small, so that the volume of the lead screw device is reduced; and at the same time, since the lead screw nut and the bearing unit are arranged along the axial direction of the lead screw, it is easy to dissipate heat, and the performance and service life of the lead screw are improved. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a structural diagram of a high-speed nut rotating feed lead screw device disclosed in the present invention. [Diagram 2] 2 is an enlarged schematic view of a portion enclosed by a dashed line in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] FIG. 1 and FIG. 2 show a high-speed nut rotating feed lead screw device including a lead screw 1, a lead screw nut 2, a bearing unit 3 and a drive unit 4 disclosed in the present invention. Both ends of the lead screw 1 are fixed to a machine tool via a lead screw base 10. The bearing unit 3 includes an inner-bearing fixed sleeve 30, an outer-bearing fixed sleeve 31, and a bearing assembly 32, the outer-bearing fixed sleeve 31 is fitted in the inner-bearing fixed sleeve 30, a bearing mounting space 33 is formed between the outer-bearing fixed sleeve 31 and the inner-bearing fixed sleeve 30, the bearing assembly 32 is mounted in the bearing mounting space 33, one end of the inner-bearing fixed sleeve 30 is a lead screw nut connecting end 34 for fixing and connecting to one end of the lead screw nut 2, and the other end is a drive unit connecting end 35 for fixing and connecting to the drive unit 4, The lead screw nut 2 is installed on the lead screw 1, and one end is fixedly connected to the lead screw nut connecting end 34 of the bearing inner fixing sleeve 30. Preferably, the lead screw and the lead screw nut are selected to have a standard lead screw structure for convenience of purchase, thereby reducing the design and manufacturing costs of the machine tool; The driving unit 4 includes a first pulley 40, a second pulley 41, a timing belt 42 and a driving motor 43, the first pulley 40 is connected to the driving motor 43, the second pulley 41 is fitted on the lead screw 1 and fixedly connected to the driving unit connecting end 35 of the bearing inner fixed sleeve 30, and the first pulley 40 and the second pulley 41 are connected via a timing belt 42, and in this embodiment, a servo motor is used as the driving motor.

[0016] Specifically, a lead screw nut connection flange 20 is provided at one end of the lead screw nut 2 facing the bearing unit 3, the bearing-fixed sleeve 30 has a stepped shaft sleeve structure, a male thread is provided at one end of the bearing-fixed sleeve 30 adjacent to the drive unit connection end 35, the bearing assembly 32 is fixed to the bearing-fixed sleeve 30 by a lock nut 39, i.e., the lock nut abuts against the inner ring of the bearing, thereby restricting the bearing to the bearing-fixed sleeve, and a bearing-fixed sleeve connection flange 300 is provided at one end of the bearing-fixed sleeve 30 facing the lead screw nut 2, and the lead screw nut connection flange The flange 20 and the bearing inner fixed sleeve connection flange 300 are fixedly connected by screws, and a pressing cover 38 is further provided at one end where a lock nut is provided, and the pressing cover 38 is fixedly connected by screws to one end adjacent to the drive unit connection end of the slide table and to one end adjacent to the drive unit connection end of the bearing outer fixed sleeve 31, respectively. The pressing cover abuts against one end of the outer ring of the bearing, thereby serving to restrict the inner ring of the bearing to the bearing outer fixed sleeve. A through hole is provided in the middle of the second pulley 41, and the second pulley is fitted onto the lead screw through the through hole and fixedly connected to the bearing inner fixed sleeve by screws.

[0017] The lead screw device disclosed in the present invention uses a driving unit to directly drive and rotate the lead screw nut, which then drives and moves the slide table, so that the lead screw nut has a small volume, light weight and small inertia, and can be driven by a driving motor with a small output, thereby reducing the volume and cost of the device, and at the same time, the small motion inertia of the entire device can realize high-speed rotation and feeding of the lead screw nut. In addition, since the lead screw nut and the bearing unit are arranged along the axial direction of the lead screw, the overall outer diameter of the lead screw nut and the bearing unit is small, and a bearing with a particularly small diameter can be used, which further reduces the moment of inertia and thereby reduces the volume of the lead screw device; at the same time, since the lead screw nut and the bearing unit are arranged along the axial direction of the lead screw, the lead screw nut is fully exposed, which makes it easy for the lead screw nut to dissipate heat, and improves the performance and service life of the lead screw; In addition, since the lead screw nut is connected through the bearing unit and both ends of the lead screw are fixed, the lead screw is equivalent to having three support points, and the driving force applied by the driving unit and the lead screw nut are close to each other, which improves the rigidity of the lead screw and allows the lead screw nut to rotate at a high speed, which greatly improves the safe rotation speed between the lead screw and the lead screw nut, and further improves the operating performance of the machine tool.

[0018] In addition, a bearing seal ring 36 is provided at one end adjacent to the lead screw nut connection end 34 between the bearing inner fixed sleeve 30 and the bearing outer fixed sleeve 31, and the bearing outer fixed sleeve 31 is further provided with an oil injection passage 37 communicating with the bearing seal ring 36. By installing the bearing seal ring structure and the oil injection passage, sealing for the bearing assembly can be realized, so as to ensure the performance of the bearing and the performance of the entire lead screw device, and to extend its service life.

[0019] Furthermore, a torque limiter 44 is further provided between the drive motor 43 and the first pulley 40. By installing the torque limiter, if an overload occurs on the machine tool due to a collision or other cause, the torque limiter is activated to protect the drive unit from damage.

[0020] Further, the bearing assembly 32 includes two sets of angular contact ball bearings installed symmetrically, each set of angular contact ball bearings including at least one angular contact ball bearing. In this embodiment, each set has two angular contact ball bearings, and the two sets of angular contact ball bearings are separated by a spacer. The use of the angular contact ball bearings can not only withstand the axial force generated between the lead screw and the lead screw nut, but also the radial force generated by the drive motor through the timing belt, thereby ensuring the performance between the lead screw nut and the lead screw and improving the service life. Preferably, an angular contact ball bearing with a contact angle of 60 degrees is used.

[0021] In addition, the lead screw 1 is further provided with a cooling passage 11 arranged along the axial direction of the lead screw. Specifically, a cooling passage is machined in the center of the lead screw along the axial direction to penetrate both ends of the lead screw. By injecting coolant into the cooling passage, the arrow in the figure indicates the flow direction of the coolant, the lead screw and the lead screw nut can be further cooled, and the performance and service life of the lead screw and the lead screw nut can be guaranteed.

[0022] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent replacements or modifications made by those skilled in the art based on the technical solutions and inventive concepts of the present invention within the technical scope disclosed in the present invention should be included in the protection scope of the present invention. [Explanation of symbols]

[0023] 1 Lead screw 10 Lead screw base 11 Cooling Channel 2 Lead screw nut 20 Lead screw nut connection flange 3 Bearing Unit 30 Bearing inner fixing sleeve 300 Bearing inner fixed sleeve connection flange 31 Bearing outer fixed sleeve 32 Bearing Assembly 33 Bearing installation space 34 Lead screw nut connection end 35 Drive unit connection end 36 Bearing seal ring 37 Oil injection passage 38 Presser cover 39 Lock nut 4 Drive unit 40 No. 1 pulley 41 No. 2 pulley 42 Timing belt 43 Drive motor 44 Torque limiter

Claims

1. A high-speed nut rotating feed lead screw device including a lead screw, a lead screw nut, a bearing unit and a drive unit, The lead screw is fixed to a machine tool via a lead screw base, the bearing unit includes an inner-bearing fixed sleeve, an outer-bearing fixed sleeve, and a bearing assembly, the outer-bearing fixed sleeve is fitted in the inner-bearing fixed sleeve, a bearing mounting space is formed between the outer-bearing fixed sleeve and the inner-bearing fixed sleeve, the bearing assembly is mounted in the bearing mounting space, one end of the inner-bearing fixed sleeve is a lead screw nut connecting end for fixing and connecting to one end of a lead screw nut, and the other end of the inner-bearing fixed sleeve is a drive unit connecting end for fixing and connecting to a drive unit, The lead screw nut is installed on the lead screw, and one end of the lead screw nut is fixedly connected to the lead screw nut connecting end of the bearing inner fixing sleeve; The high-speed nut rotating feed lead screw device, characterized in that the drive unit includes a first pulley, a second pulley, a timing belt and a drive motor, the first pulley is connected to the drive motor, the second pulley is fitted to the lead screw and is fixedly connected to the drive unit connection end of the bearing inner fixed sleeve, and the first pulley and the second pulley are connected via a timing belt.

2. 2. The high-speed nut rotating feed lead screw device according to claim 1, further comprising a bearing seal ring provided at one end adjacent to the lead screw nut connecting end between the bearing inner fixed sleeve and the bearing outer fixed sleeve.

3. 3. The high-speed nut rotating feed lead screw device according to claim 2, wherein the bearing outer fixed sleeve is further provided with an oil injection passage communicating with the bearing seal ring.

4. 4. The high-speed nut rotating feed lead screw device according to claim 1, further comprising a torque limiter provided between the driving motor and the first pulley.

5. 5. The high-speed nut rotating feed lead screw device as claimed in claim 4, characterized in that the bearing assembly includes two sets of symmetrically installed angular contact ball bearings, each set of angular contact ball bearings including at least one angular contact ball bearing.

6. 2. The high-speed nut rotating feed lead screw device according to claim 1, characterized in that the sleeve fixed in the bearing has a stepped shaft sleeve structure, a male thread is provided at one end of the sleeve fixed in the bearing adjacent to the drive unit connection end, and the bearing assembly is fixed to the sleeve fixed in the bearing by a lock nut.

7. 7. The high-speed nut rotating feed lead screw device according to claim 6, further comprising a retaining cover, the retaining cover being fixedly connected by screws to one end of the slide table adjacent to the drive unit connection end and one end of the bearing outer fixed sleeve adjacent to the drive unit connection end.

8. The high-speed nut rotating feed lead screw device according to any one of claims 1 to 3, characterized in that the lead screw is further provided with a cooling passage arranged along the axial direction of the lead screw.

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