Lead screw pre-stretching mechanism for numerical control machine tool

Abstract

The invention belongs to the technical field of numerical control machine tool equipment, and particularly relates to a lead screw pre-stretching mechanism for a numerical control machine tool. The device comprises a bearing seat, a lead screw and a tensioning nut used for pre-stretching the lead screw, one end of the lead screw is rotationally installed in the bearing seat through a pair of bearings, an installation hole used for installing the lead screw is formed in the bearing seat, an installation groove used for installing the bearings is formed in one side of the installation hole, and a spacer ring seat is connected into the installation groove; a bearing gland is fixedly mounted at one end of the bearing seat, and is matched with the spacer ring seat to seal the mounting groove; a supporting structure is installed in the installation hole and used for supporting the bearing, and the lead screw is in threaded connection with a locking nut used for pressing the supporting structure. According to the pre-stretching mechanism, the supporting structure is installed in the bearing seat to support the inner ring of the bearing, the problem that one side face of the inner ring of the bearing is damaged due to large axial force is avoided, the effect of protecting the bearing is achieved, and the overall structural strength of the pre-stretching mechanism is improved.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool technology, and in particular to a lead screw pretensioning mechanism for CNC machine tools. Background Technology

[0002] In the feed transmission system of machine tools, lead screws are often used as transmission elements to convert the rotary motion of servo motors into linear movement of motion actuators (tool holders or worktables, etc.). The lead screw is mainly installed in a pre-stretched state through a lead screw pre-tensioning mounting device. Since the lead screw generates heat during operation, its temperature changes cause thermal expansion and contraction, which has a significant impact on the transmission accuracy of the lead screw. By pre-stretching the lead screw, the elongation caused by temperature changes can be compensated to a certain extent.

[0003] The existing machine tool lead screw pretensioning structure is connected to the lead screw by a pretension nut. Rotating the pretension nut can pretension the lead screw. When the lead screw is tensioned, the pretension nut applies a large axial force to the inner ring, outer ring and bearing housing of the bearing. The large axial force may cause damage to the bearing. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a lead screw pretensioning mechanism for CNC machine tools. By installing a support structure inside the bearing housing to support the inner ring of the bearing, the axial force borne by the bearing is shared, thereby solving the problems in the prior art.

[0005] To achieve the above-mentioned technical objectives, the specific technical solution of the present invention is as follows: The present invention proposes a lead screw pre-tensioning mechanism for CNC machine tools, comprising: a bearing housing, a lead screw, and a tensioning nut for pre-tensioning the lead screw. One end of the lead screw is rotatably mounted in the bearing housing via a pair of bearings. The bearing housing has a mounting hole for mounting the lead screw, and a mounting groove for mounting the bearing is provided on one side of the mounting hole. A spacer seat is connected in the mounting groove, wherein the spacer seat is located between the tensioning nut and the bearing, and the two end faces of the spacer seat are in contact with the tensioning nut and the inner ring surface of the bearing, respectively. A bearing cap is fixedly mounted on one end of the bearing housing, and the bearing cap and the spacer seat cooperate to seal the mounting groove. A support structure is installed in the mounting hole for supporting the bearing. The support structure and the spacer seat are respectively located on both sides of the bearing, and a locking nut for tightening the support structure is threaded onto the lead screw. One end surface of the lead screw has a first threaded portion and a second threaded portion, wherein the locking nut is threadedly connected to the first threaded portion, and the tensioning nut is threadedly connected to the second threaded portion.

[0006] As a preferred embodiment of the present invention, the support structure includes a pressure ring, a disc spring, and a pressure sleeve. One end of the pressure sleeve contacts the surface of the inner ring of the bearing, the pressure ring contacts the locking nut, and the disc spring is disposed between the pressure ring and the pressure sleeve.

[0007] As a preferred embodiment of the present invention, the pressure ring has an annular groove on its circumferential surface, and a sealing ring is connected inside the annular groove for sealing between the pressure ring and the mounting hole; the disc springs are provided in two symmetrically distributed.

[0008] As a preferred embodiment of the present invention, the pressure sleeve is provided with a pair of first bearing rings at both ends, and a plurality of first reinforcing rods are uniformly provided on the surface of the pressure sleeve along its circumference.

[0009] As a preferred embodiment of the present invention, one end of the spacer seat is provided with a second bearing ring, which contacts the inner ring surface of the bearing, and the other end of the spacer seat is provided with an abutment ring, which contacts the tensioning nut.

[0010] As a preferred embodiment of the present invention, a fixing ring is fixedly connected to the contact ring, and a folding ring is provided on the fixing ring. A first connecting ring is fixedly connected to the surface of the bearing cover, and the first connecting ring is connected between the folding ring and the inner wall of the mounting groove.

[0011] As a preferred embodiment of the present invention, a second connecting ring is fixedly connected to the surface of the bearing cap, and a sealing groove is formed between the first connecting ring and the second connecting ring, and the folding ring is sealed and connected in the sealing groove.

[0012] As a preferred embodiment of the present invention, a ring-shaped sealing gasket is connected inside the sealing groove, and the sealing gasket is disposed between the folding ring and the second connecting ring.

[0013] As a preferred embodiment of the present invention, the surface of the spacer seat is provided with a plurality of second reinforcing rods evenly distributed along its circumference.

[0014] The beneficial effects of this invention are as follows: 1. This invention provides support for the inner ring of the bearing by installing a support structure inside the bearing housing, thereby preventing damage to one side of the inner ring from excessive axial force and protecting the bearing. This also improves the overall structural strength of the pre-tensioning mechanism.

[0015] 2. The support structure of the present invention is provided with a pressure ring, a disc spring and a pressure sleeve. The disc spring can better balance the axial force on the inner ring of the bearing, and the support structure is locked and limited by the locking nut, which ensures the support force of the support structure on the inner ring of the bearing. The support force of the support structure on the inner ring of the bearing can be adjusted by the locking nut to match the different extension amounts of the lead screw.

[0016] 3. The present invention, through the cooperation of locking nut and support structure, transfers part of the axial force received by the bearing and bearing housing to the lead screw, thereby reducing the pressure on the bearing and bearing housing and playing a role in protecting the bearing and bearing housing. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention.

[0018] Figure 2 This is an exploded view of the present invention.

[0019] Figure 3 This is a cross-sectional schematic diagram of the present invention.

[0020] Figure 4 This is a schematic diagram of the bearing housing structure proposed in this invention.

[0021] Figure 5 This is a schematic diagram of the support structure proposed in this invention.

[0022] Figure 6 This is a schematic diagram of the spacer seat proposed in this invention.

[0023] Figure 7 for Figure 6 Another perspective diagram.

[0024] Figure 8 This is a schematic diagram of the bearing cap structure proposed in this invention.

[0025] The corresponding names of the reference numerals in the figure are as follows: 1. Bearing housing; 101. Mounting hole; 102. Mounting groove; 2. Lead screw; 201. First threaded part; 202. Second threaded part; 3. Support structure; 31. Pressure ring; 311. Sealing ring; 312. Annular groove; 32. Disc spring; 33. Pressure sleeve; 331. First bearing ring; 332. First reinforcing rod; 4. Locking nut; 5. Bearing; 6. Spacer seat; 601. Second bearing ring; 602. Fixing ring; 603. Second reinforcing rod; 604. Contact ring; 605. Folding ring; 7. Bearing cover; 701. First connecting ring; 702. Second connecting ring; 703. Sealing groove; 8. Sealing gasket; 9. Tensioning nut. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0027] Example: This example discloses a lead screw pretensioning mechanism for CNC machine tools, such as... Figures 1-8As shown, the assembly includes: a bearing housing 1, a lead screw 2, and a tension nut 9 for pre-tensioning the lead screw 2. One end of the lead screw 2 is rotatably mounted in the bearing housing 1 via a pair of bearings 5, which are installed face-to-face. The bearing housing 1 has a mounting hole 101 for mounting the lead screw 2, and a mounting groove 102 for mounting the bearings 5 ​​is provided on one side of the mounting hole 101. The diameter of the mounting groove 102 is larger than the diameter of the mounting hole 101. A spacer seat 6 is connected in the mounting groove 102. The spacer seat 6 is located between the tension nut 9 and the bearings 5, and its two end faces contact the tension nut 9 and the inner ring surface of the bearing 5, respectively. The spacer seat 6 is used to press the inner ring of the bearing 5. One end of the bearing is fixed with a bearing cap 7 by bolts. Under the pressure of the tension nut 9, the bearing cap 7 presses against the outer ring of the bearing 5. The bearing cap 7 and the spacer seat 6 cooperate to seal the mounting groove 102. When the lead screw 2 rotates, it drives the inner ring of the bearing 5, the spacer seat 6 and the tension nut 9 to rotate together. The surface of one end of the lead screw 2 is provided with a first thread 201 and a second thread 202. The tension nut 9 is threadedly connected to the second thread 202. By rotating the tension nut 9, the tension nut 9 applies axial pressure to the spacer seat 6. The spacer seat 6 applies axial pressure to the inner ring of the bearing 5, thereby stretching the lead screw 2 to compensate for the elongation caused by the heat of the lead screw.

[0028] like Figure 3 and Figure 5As shown, a support structure 3 is installed in the mounting hole 101 to support the inner ring of the bearing 5. The support structure 3 and the spacer seat 6 are respectively located on both sides of the bearing 5, and a locking nut 4 for pressing the support structure 3 is threaded onto the lead screw 2. The locking nut 4 is threaded to the first threaded part 201. The support structure 3 includes a pressure ring 31, a disc spring 32, and a pressure sleeve 33. The pressure sleeve 33 is connected to the lead screw 2. When the lead screw 2 rotates, it drives the pressure sleeve 33, the disc spring 32, the pressure ring 31, and the locking nut 4 to rotate together. One end of the pressure sleeve 33 contacts the surface of the inner ring of the bearing 5, and the pressure ring 31 contacts the locking nut 4. The disc spring 32 is located between the pressure ring 31 and the pressure sleeve 33. There are two disc springs 32, which are symmetrically distributed. The deformation generated by the disc spring 32 can continuously support the inner ring of the bearing 5, providing a lasting support force and preventing the support structure 3 from loosening. In this embodiment, the locking nut 4 is rotated to apply axial pressure to the pressure ring 31. The pressure ring 31 transmits the axial pressure to the pressure sleeve 33 through the disc spring 32, so that the inner ring of the bearing 5 is subjected to forces in opposite directions on both sides, thereby supporting and protecting the inner ring of the bearing 5. The beneficial effect of this embodiment compared with the prior art is that by providing a support structure 3 in the bearing housing 1 to support the inner ring of the bearing 5, the axial pressure applied by the tension nut 9 is shared, thus protecting the bearing 5. Moreover, the support force of the support structure 3 on the inner ring of the bearing can be adjusted by the locking nut 4 to match different tension amounts of the lead screw 2. In this embodiment, when the lead screw 2 is installed, the tension nut 9 is tightened to pre-tension the lead screw 2. At the same time as the tensioning, the locking nut 4 automatically applies pressure to the disc spring 32, and the disc spring 32 automatically deforms, automatically increasing the support force on the inner ring of the bearing 5.

[0029] Preferably, the pressure ring 31 has an annular groove 312 on its circumference, and a sealing ring 311 is connected inside the annular groove 312. The sealing ring 311 seals the pressure ring 31 and the mounting hole 101 to prevent dust from entering or oil from leaking.

[0030] Preferably, the pressure sleeve 33 is provided with a pair of first bearing rings 331 at both ends, which increases the force-bearing area of ​​the pressure sleeve 33, and a number of first reinforcing rods 332 are uniformly provided on the surface of the pressure sleeve 33 along its circumference, which enhances the structural strength of the pressure sleeve 33 and prevents the pressure sleeve 33 from deforming.

[0031] like Figures 6-8As shown, one end of the spacer seat 6 is provided with a second bearing ring 601, which contacts the inner ring surface of the bearing 5 and increases the contact area between the spacer seat 6 and the inner ring of the bearing 5. The other end of the spacer seat 6 is provided with an abutment ring 604, which contacts the tension nut 9. A fixing ring 602 is fixedly connected to the abutment ring 604, and a folding ring 605 is vertically provided on the side of the fixing ring 602. A first connecting ring 701 is fixedly connected to the surface of the bearing cover 7, and the first connecting ring 701 connects the folding ring 605 and the mounting groove 1. Between the inner walls of bearing 5 and bearing 6, the first connecting ring 701 presses against the outer ring of bearing 5, thus securing bearing 5. A second connecting ring 702 is fixedly connected to the surface of bearing cap 7. A sealing groove 703 is formed between the first connecting ring 701 and the second connecting ring 702. A folding ring 605 is connected in the sealing groove 703, and a ring-shaped sealing gasket 8 is connected in the sealing groove 703. The sealing gasket 8 is located between the folding ring 605 and the second connecting ring 702. The sealing gasket 8 seals the bearing cap 7 and the spacer seat 6 to prevent oil leakage.

[0032] Preferably, a plurality of second reinforcing rods 603 are uniformly provided on the surface of the spacer ring seat 6 along its circumference to improve the overall structural strength of the spacer ring seat 6 and prevent the spacer ring seat 6 from deforming under pressure.

[0033] Working principle: In this embodiment, a support structure 3 is installed inside the bearing housing 1, and the support structure 3 is pressed by the locking nut 4. The disc spring 32 deforms, so that the support structure 3 can provide a sustained support force to one side of the inner ring of the bearing 5, so as to counteract the axial pressure applied by the tension nut 9 to the other side of the inner ring of the bearing 5, thus protecting the bearing 5. In addition, the axial pressure on the bearing 5 and the bearing housing 1 is transmitted to the lead screw 2 through the support structure 3. The lead screw 2 shares part of the pressure on the bearing 5 and the bearing housing 1, which disperses the pressure, improves the overall structural strength of the pre-tensioning mechanism, and improves the service life of the lead screw 2 and the bearing 5.

[0034] Finally, it should be noted that in the description of this invention, the terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lead screw pretensioning mechanism for CNC machine tools, comprising: The bearing housing (1), the lead screw (2), and the tension nut (9) for pre-tensioning the lead screw (2), wherein one end of the lead screw (2) is rotatably mounted in the bearing housing (1) via a pair of bearings (5), characterized in that: The bearing housing (1) is provided with a mounting hole (101) for mounting the lead screw (2), and a mounting groove (102) for mounting the bearing (5) is provided on one side of the mounting hole (101). A spacer seat (6) is connected in the mounting groove (102). The spacer seat (6) is located between the tension nut (9) and the bearing (5). The two end faces of the spacer seat (6) are in contact with the tension nut (9) and the inner ring surface of the bearing (5), respectively. The bearing housing (1) is fixedly installed with a bearing cover (7) at one end, and the bearing cover (7) cooperates with the spacer seat (6) to seal the mounting groove (102); A support structure (3) is installed in the mounting hole (101) to support the bearing (5). The support structure (3) and the spacer seat (6) are respectively located on both sides of the bearing (5), and a locking nut (4) for pressing the support structure (3) is threaded on the screw (2). The lead screw (2) has a first threaded part (201) and a second threaded part (202) on one end surface. The locking nut (4) is threaded to the first threaded part (201), and the tensioning nut (9) is threaded to the second threaded part (202).

2. The lead screw pre-tensioning mechanism for CNC machine tools according to claim 1, characterized in that, The support structure (3) includes a pressure ring (31), a disc spring (32) and a pressure sleeve (33). One end of the pressure sleeve (33) contacts the inner ring surface of the bearing (5), the pressure ring (31) contacts the locking nut (4), and the disc spring (32) is located between the pressure ring (31) and the pressure sleeve (33).

3. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 2, characterized in that, The pressure ring (31) has an annular groove (312) on its circumference, and a sealing ring (311) is connected inside the annular groove (312) to seal between the pressure ring (31) and the mounting hole (101); the disc spring (32) has two and is symmetrically distributed.

4. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 2, characterized in that, The pressure sleeve (33) has a pair of first bearing rings (331) at both ends, and a number of first reinforcing rods (332) are evenly arranged on the surface of the pressure sleeve (33) along its circumference.

5. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 4, characterized in that, One end of the spacer seat (6) is provided with a second bearing ring (601), which contacts the inner ring surface of the bearing (5). The other end of the spacer seat (6) is provided with an abutment ring (604), which contacts the tension nut (9).

6. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 5, characterized in that, A fixing ring (602) is fixedly connected to the contact ring (604), and a folding ring (605) is provided on the fixing ring (602). A first connecting ring (701) is fixedly connected to the surface of the bearing cover (7), and the first connecting ring (701) is connected between the folding ring (605) and the inner wall of the mounting groove (102).

7. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 6, characterized in that, The bearing cap (7) is fixedly connected to a second connecting ring (702), and a sealing groove (703) is formed between the first connecting ring (701) and the second connecting ring (702). The folding ring (605) is sealed and connected in the sealing groove (703).

8. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 7, characterized in that, The sealing groove (703) is connected to a ring-shaped sealing gasket (8), which is located between the folding ring (605) and the second connecting ring (702).

9. A lead screw pre-tensioning mechanism for CNC machine tools according to claim 8, characterized in that, The surface of the spacer seat (6) is uniformly provided with a number of second reinforcing rods (603) along its circumference.

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