Hollow lead screw cooling system connecting structure and numerical control machine tool

Abstract

The hollow lead screw cooling system connecting structure comprises a connector, one end of the connector is provided with a protrusion with external threads, and the external threads of the protrusion are connected with internal threads of an inner hole in the tail end of a lead screw in a matched mode; a high-precision outer circle is arranged on the periphery of the protrusion and is in clearance fit with a high-precision inner hole in an opening in the tail end of the lead screw, and the coaxiality is guaranteed. A sealing ring groove is formed between the external thread and the high-precision outer circle, and a sealing ring is arranged in the sealing ring groove to achieve sealing with the lead screw. A middle oil return channel and a backflow hole communicated with the hollow inner hole of the lead screw and the rotary joint are arranged in the connector, a middle oil inlet channel of the rotary joint penetrates through the hollow inner hole of the lead screw through a hose, extends to the position near the motor end and is provided with an outlet, and constant-temperature cooling oil flows out of the outlet of the hose and flows back through the oil return channel to form a cooling oil circulation path. According to the connector designed by the utility model, a common universal two-way rotary joint in the market can be used for feeding and discharging the cooling oil of the hollow screw rod, and a special rotary joint is not needed.

Description

Technical Field

[0001] This utility model relates to the technical field of lead screw cooling connection structure, and in particular to a connection structure for a hollow lead screw cooling system and a CNC machine tool. Background Technology

[0002] Currently, hollow oil-cooled lead screws used in CNC machine tools on the market can significantly reduce the thermal expansion of the lead screw during operation and improve the accuracy of the machine tool by using constant-temperature cooling oil to remove the heat generated by the rotation of the lead screw.

[0003] There are two existing methods to achieve cooling oil passing through the lead screw:

[0004] 1. Cooling oil enters from one end of the lead screw and exits from the other end. This method uses a rotary joint at both ends of the lead screw, with the rotary joint at the end closest to the drive motor and coupling being integrated with the coupling.

[0005] 2. A special rotary joint is used to allow cooling oil to enter from one end of the lead screw and exit from the same end of the lead screw.

[0006] Since one end of the lead screw needs to be connected to the drive motor via a coupling, if a rotary joint is also required, the coupling structure will become complicated, requiring both transmission and oil passage, resulting in higher costs.

[0007] Because the hollow lead screw has only one hole inside, a special rotary joint must be used if the cooling oil is to enter and exit from the same end. This rotary joint is troublesome to install, has high technical requirements, and the distance between the end face of the hollow lead screw and the end face of the machine tool bearing seat must be strictly controlled. If maintenance such as bearing replacement is encountered during machine tool use, the installation status of the special rotary joint will be affected during the disassembly and assembly process. Therefore, this rotary joint is easily damaged, resulting in oil leakage and other damage.

[0008] In summary, these factors seriously hinder the widespread use of hollow oil-cooled screws. Utility Model Content

[0009] The technical solution of this utility model to solve the above-mentioned technical problems is to provide a connection structure for a hollow lead screw cooling system, including a connector, one end of which is provided with a protrusion with an external thread. The external thread of the protrusion is adapted to connect with the internal thread of the inner hole at the tail end of the lead screw. The outer periphery of the protrusion is provided with a high-precision outer circle, which is clearance-fitted with the high-precision inner hole in the opening at the tail end of the lead screw to ensure coaxiality. A sealing ring groove is provided between the external thread and the high-precision outer circle, and a sealing ring is built in to achieve sealing with the lead screw.

[0010] The other end of the connector is provided with a threaded hole for fixing the rotary joint;

[0011] The spindle of the rotary joint is connected to the oil inlet hose, which passes through the middle oil return channel of the connector and through the hollow inner hole of the lead screw, extending to the vicinity of the motor end;

[0012] The outer diameter of the hose is smaller than the inner diameter of the connector's central oil return hole and the hollow lead screw. The gap between the hose's outer diameter and the connector's central oil return hole, as well as between the hose and the hollow lead screw's inner diameter, serves as an oil return channel, carrying away heat from the lead screw during the oil return process. The connector has an internal oil return channel that connects to the rotary joint's return hole, forming a cooling oil circulation path.

[0013] Furthermore, the connector is provided with anti-rotation screw holes, which are used to tighten the lead screw with screws to prevent the connector from loosening when the lead screw frequently starts and stops at high speed during operation.

[0014] A CNC machine tool, comprising:

[0015] Drive motor;

[0016] A lead screw, wherein the drive motor is connected to one end of the lead screw via a coupling;

[0017] A bearing housing, which is supported at the tail end of the lead screw;

[0018] As described above, in the hollow screw cooling system connection structure, the connector of the hollow screw cooling system connection structure is connected to the end of the screw away from the drive motor.

[0019] Furthermore, the bearing housing includes: a housing body, a bearing cover, and a bearing. The bearing is installed in the mounting hole of the housing body, the bearing cover abuts against the outer ring of the bearing, and the lead screw locking nut is disposed in the mounting hole to press the inner ring of the bearing, thereby adjusting the bearing preload and fixing the axial position of the lead screw.

[0020] The technical solution of this utility model, through the design of a connector, allows the use of a common universal dual-path rotary joint for the inlet and outlet of cooling oil in hollow lead screws, eliminating the need for a specially made rotary joint. The connector + universal rotary joint in this solution not only has a long service life but is also easier to install. The connector is not connected to the bearing housing, so there is no need to control the distance between the end face of the lead screw and the end face of the bearing housing. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the connection structure of the hollow screw cooling system described in this utility model;

[0023] Figure 2 This is a schematic diagram of the connection structure of the hollow lead screw cooling system of this utility model, adapted to the lead screw and universal rotary joint;

[0024] Figure 3 This is a schematic diagram of a certain axial structure of the CNC machine tool described in this utility model.

[0025] Explanation of icon numbers:

[0026] Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0029] Furthermore, in this utility model, the use of terms such as "first" and "second" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "several" or "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0030] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0032] This utility model proposes a connection structure for a hollow screw cooling system and a CNC machine tool. The aim is to design a connection structure that can use a common universal dual-path rotary joint for the inlet and outlet of cooling oil in the hollow screw, and it is easy to install.

[0033] The specific structure of the hollow screw cooling system connection structure proposed in this utility model will be described below in a specific embodiment:

[0034] Example 1:

[0035] A connection structure for a hollow screw cooling system, such as Figure 1 , Figure 2 As shown, it includes a connector 10, one end of which is provided with a protrusion with an external thread 11. The external thread 11 of the protrusion is adapted to connect with the internal thread of the inner hole of the tail end of the lead screw 50. The outer periphery of the protrusion is provided with a high-precision outer circle 12, which is clearance-fitted with the high-precision inner hole in the opening of the tail end of the lead screw 50 to ensure coaxiality. A sealing ring groove 13 is provided between the external thread 11 and the high-precision outer circle 12, and a sealing ring 70 is built in to achieve sealing with the lead screw 50.

[0036] The other end of the connector 10 is provided with a threaded hole 14 for fixing the rotary joint 30;

[0037] The central oil inlet channel of the rotary joint 30 extends to the motor end through a hose passing through the hollow inner hole of the lead screw;

[0038] The connector 10 has an internal intermediate oil return channel 15. One end of the intermediate oil return channel 15 of the connector 10 is connected to the inner hole of the hollow screw, and the other end is connected to the return hole of the rotary joint, forming a complete oil return channel.

[0039] The spindle of the rotary joint 30 is connected to the flexible hose 20. The flexible hose 20 passes through the central oil return hole 15 of the connector and extends through the hollow inner hole of the lead screw 50 to the vicinity of the motor end. The cooled and constant-temperature oil exits from the hose outlet near the motor end through the hose and flows back through the gap between the hose and the hollow inner hole of the lead screw. During the return flow, the heat of the lead screw is carried away. Then, it connects to the return hole of the rotary joint 30 through the oil return channel 15 of the connector, forming a cooling oil circulation path.

[0040] Specifically, the rotary joint 30 has an oil inlet 31 and an oil return hole 32. The oil inlet 31 is connected to the hose 20, and the oil return hole 32 is connected to the intermediate oil return hole 15. A sealing ring 80 is provided between the rotary joint 30 and the connector 10.

[0041] Furthermore, the connector 10 is provided with an anti-rotation screw hole 16 for tightening the lead screw 50 with a screw.

[0042] Working principle: The constant temperature cooling oil is output through the oil outlet of the constant temperature oil cooler and enters the shaft of the rotary joint 30 through the oil inlet of the rotary joint 30 via the oil pipe. The constant temperature cooling oil entering the rotary joint 30 enters the oil inlet hose 20 through the connector of the oil inlet hose 20 and reaches the depth of the center hole of the lead screw 50 (near the end of the drive motor 40) along the oil inlet hose 20. The outlet of the hose 20 is open. After the constant temperature cooling oil flows out of the hose 20, it flows back in the gap between the outer wall of the hose 20 and the inner wall of the center hole of the lead screw 50. During the flow of the cooling oil, the heat of the lead screw 50 is transferred to the cooling oil. The returning cooling oil passes through the middle oil return channel 15 of the connector 10 and enters the cooling oil return hole of the rotary joint 30. After passing through the rotary joint 30, it comes out from the cooling oil outlet of the rotary joint 30 and flows back into the constant temperature oil cooler through the oil pipe for cooling and constant temperature. Then, the oil flows out of the constant temperature oil cooler outlet again, passes through the oil pipe, and re-enters the oil inlet of the rotary joint 30, circulating repeatedly. This ensures that the heat generated during the operation of the lead screw 50 is carried away in time, preventing changes in accuracy caused by thermal expansion.

[0043] Example 2:

[0044] A type of CNC machine tool, such as Figure 3 As shown, it includes:

[0045] Drive motor 40;

[0046] The lead screw 50 and the drive motor 40 are connected to one end of the lead screw 50 via a coupling.

[0047] Bearing housing 60, bearing housing 60 is supported at the tail end of lead screw 50;

[0048] As in Embodiment 1 above, the connector 10 of the hollow screw cooling system connection structure is connected to the end of the screw 50 away from the drive motor 40.

[0049] Furthermore, the bearing housing 60 includes: a housing body 61, a lead screw locking nut 62, a bearing cover 63, and a bearing 64. The bearing 64 is installed in the mounting hole of the housing body 61, the bearing cover 63 abuts against the outer ring of the bearing 64, and the lead screw locking nut 62 is disposed in the mounting hole to press the inner ring of the bearing, which is used to adjust the preload of the bearing 64 and fix the axial position of the lead screw 50.

[0050] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A connection structure for a hollow screw cooling system, characterized in that, include: The connector has a protrusion with an external thread at one end, which is adapted to connect with the internal thread of the inner hole at the tail end of the lead screw; the outer circumference of the protrusion has a high-precision outer circle, which is clearance-fitted with the high-precision inner hole in the opening at the tail end of the lead screw to ensure coaxiality; a sealing ring groove is provided between the external thread and the high-precision outer circle, and a sealing ring is built in to achieve sealing with the lead screw. The other end of the connector is provided with a threaded hole for fixing the rotary joint; The central oil inlet channel of the rotary joint extends to the motor end through a hose passing through the hollow inner hole of the lead screw; The connector has an internal intermediate oil return channel that connects the hollow inner hole of the lead screw with the return hole of the rotary joint, forming a cooling oil circulation path.

2. The connection structure of the hollow screw cooling system according to claim 1, characterized in that, The connector is provided with anti-rotation screw holes for tightening the lead screw with screws.

3. A CNC machine tool, characterized in that, include: Drive motor; A lead screw, wherein the drive motor is connected to one end of the lead screw via a coupling; A bearing housing, which is supported at the tail end of the lead screw; and The hollow screw cooling system connection structure as described in claim 1, wherein the connector of the hollow screw cooling system connection structure is connected to the end of the screw away from the drive motor.

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