Hydraulic damping dynamic pre-tightening mechanism for motorized spindle

Abstract

The invention discloses an electric spindle hydraulic damping dynamic pre-tightening mechanism, and relates to the technical field of electric spindle inner bearing pre-tightening. The problem that radial expansion is unstable due to abrasion in the using process of a spiral coil is solved. The device specifically comprises a machine shell, the two ends of the machine shell are connected with a first end cover and a second end cover through bolts respectively, the side, close to the first end cover, of the machine shell is sleeved with a flange, a clamping key nut is arranged in the middle of the end face of the first end cover, and a connecting base is fixedly connected to the middle of the end face of the second end cover. When the motorized spindle is at a low rotating speed, the calorific value of the bearing is small, and the pre-tightening force of the bearing is large through oil gas input, when the motorized spindle is at a high rotating speed, the calorific value of the bearing is large, and the pre-tightening force of the bearing is small through oil gas output, so that the hydraulic damping dynamic pre-tightening adjusting function of the motorized spindle is achieved; the safety of the electric spindle inner bearing is protected, the working stability of the electric spindle inner bearing is promoted, and the service life of the electric spindle inner bearing is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of pre-tightening inner bearings of electric spindles, in particular to a hydraulic damping dynamic pre-tightening mechanism of an electric spindle. Background Art

[0002] The hydraulic damping dynamic preload of the electric spindle is a preload system for the spindle of a machine tool. Its main function is to provide additional preload force through hydraulic damping when the spindle rotates at high speed, so as to improve the rigidity and stability of the spindle, reduce vibration and noise, and improve processing accuracy and surface quality. In the traditional spindle system of a machine tool, spring or air pressure preload is usually used to provide the preload force of the spindle, but this method has some limitations, such as the preload force is not easy to adjust and the stability is poor. The hydraulic damping dynamic preload system of the electric spindle provides the preload force through the hydraulic device, which can realize the real-time adjustment and control of the preload force, so that the spindle can be more stable and reliable when rotating at high speed. In addition, the hydraulic damping dynamic preload system of the electric spindle can also adjust the size of the preload force in real time according to the speed and load of the spindle to ensure that the spindle can obtain the best performance under different working conditions. This system can effectively improve the dynamic characteristics of the spindle, improve processing efficiency and quality, and is widely used in high-speed and high-precision processing machine tools.

[0003] After searching, the invention of Chinese patent application number CN2019110250468 discloses an electric spindle bearing preload device, an electric spindle and a machine tool. The electric spindle bearing preload device includes a fixing part, a preload part, a spiral coil and a coil controller, and the coil controller is electrically connected to the spiral coil; the preload part can move relative to the fixing part along the axial direction of the fixing part, and in the axial direction of the fixing part, the preload part has a bearing abutment surface facing away from the fixing part; in the axial direction of the fixing part, the spiral coil is arranged between the fixing part and the preload part, and the extension direction of the spiral coil is perpendicular to the axial direction of the fixing part. The electric spindle includes an electric spindle bearing preload device. The machine tool includes an electric spindle. After the spiral coil is energized, it will expand radially, and the radial ends of the spiral coil tube will abut on the fixing part and the preload part respectively. The radial expansion of the spiral coil causes a change in the abutment force on the preload part, and then causes a change in the preload force on the outer ring of the bearing. The electric spindle bearing preload device, electric spindle and machine tool in the above invention have the following shortcomings:

[0004] Although the radial expansion of the spiral coil in the above-mentioned device causes changes in the abutment force on the preloaded part and changes in the preload force on the outer ring of the bearing, the spiral coil may have unstable radial expansion due to wear during use, which leads to instability in the preload force, causing fluctuations in the preload force, causing problems with bearing stability, and affecting the efficiency of the bearing. Therefore, there is an urgent need for an electric spindle hydraulic damping dynamic preload mechanism. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings in the prior art and to propose an electric spindle hydraulic damping dynamic preload mechanism.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The electric spindle hydraulic damping dynamic preload mechanism comprises a casing, wherein two ends of the casing are respectively connected with an end cover 1 and an end cover 2 by bolts, and a flange is sleeved on a side of the casing close to the end cover 1, a key nut is arranged in the middle of the end face of the end cover 1, a connecting seat is fixedly connected in the middle of the end face of the end cover 2, and a dynamic preload adjustment mechanism is arranged inside the side of the casing close to the end cover 2;

[0008] The circumferential outer wall of the second end cover close to the circumferential side of the connecting seat is respectively provided with an oil and gas inlet and an oil and gas outlet connected with the oil pipe of the hydraulic system.

[0009] Preferably: the dynamic preload adjustment mechanism includes an outlet channel, a transition sleeve, a bearing seat, an oil-gas gap and an inlet channel, and the outlet channel is opened in the top inner wall where the casing and the end cover are in contact with each other.

[0010] Furthermore, the inlet channel is opened in the bottom inner wall where the casing and the end cover are in contact with each other, and the transition sleeve is fixedly connected to the inside of the casing.

[0011] On the basis of the above-mentioned scheme: the bearing seat is arranged in the inner circumference of the transition sleeve, and the oil-gas gap is respectively arranged at the place where the transition sleeve and the bearing seat are fitted to each other.

[0012] A better solution among the above solutions is that: the outlet channel is connected to the oil and gas outlet, and the diameter of the oil and gas outlet is larger than the diameter of the outlet channel.

[0013] As a further solution of the present invention: the inlet channel is connected to the oil and gas inlet, and the diameter of the oil and gas inlet is larger than the diameter of the inlet channel.

[0014] At the same time, the transition sleeve and the bearing seat are mutually clamped.

[0015] The beneficial effects of the present invention are:

[0016] The electric spindle hydraulic damping dynamic preload mechanism, when the electric spindle sends a low-speed rotation signal through the drive system, the hydraulic system injects a large amount of oil into the oil and gas inlet, and the oil enters the bearing seat through the inlet channel. During this period, the oil pressure is measured by the pressure sensor of the hydraulic system oil pipe. Since the bearing is at a low speed, the bearing heat is small, and it is difficult to form an oil film in the oil gap between the bearing and the shaft, which increases the friction. By injecting oil into the bearing to increase the bearing preload, the bearing is guaranteed to better bear the load and reduce wear. When the electric spindle sends a high-speed rotation signal through the drive system, the hydraulic system outputs A certain amount of oil is released from the outlet channel, and the oil flows back into the hydraulic system through the oil and gas outlet. During this period, the oil pressure is measured by the pressure sensor of the hydraulic system oil pipe. At the same time, since the bearing is at a high speed, the bearing generates a lot of heat. Through the action of large centrifugal force, the oil inside the bearing forms an oil film, and the hydraulic system extracts a certain amount of oil from the bearing, which promotes the flow and dispersion of the lubricating oil in the bearing, forming a more stable and complete lubricating oil film, and the oil film is separated from the friction surface, which reduces the friction coefficient, reduces the friction force, and reduces the bearing wear. At this time, the preload force in the bearing is reduced due to the extraction of hydraulic oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a left-side structural schematic diagram of the electric spindle hydraulic damping dynamic preload mechanism proposed by the present invention;

[0018] Figure 2 It is a right side structural schematic diagram of the hydraulic damping dynamic preload mechanism of the electric spindle proposed by the present invention;

[0019] Figure 3 It is a schematic diagram of the right end surface structure of the hydraulic damping dynamic preload mechanism of the electric spindle proposed by the present invention;

[0020] Figure 4 It is a schematic diagram of the left end surface structure of the hydraulic damping dynamic preload mechanism of the electric spindle proposed by the present invention;

[0021] Figure 5 This is a partial cross-sectional structural schematic diagram of the electric spindle hydraulic damping dynamic preload mechanism proposed by the present invention.

[0022] In the figure: 1. Casing; 2. End cover 1; 3. Flange; 4. End cover 2; 5. Connecting seat; 6. Oil and gas inlet; 7. Oil and gas outlet; 8. Key nut; 9. Outlet channel; 10. Transition sleeve; 11. Bearing seat; 12. Oil and gas gap; 13. Inlet channel. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0024] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0025] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected or set, or detachably connected or set, or integrally connected or set. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] The hydraulic damping dynamic preload mechanism of the electric spindle, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, it includes a casing 1, and the two ends of the casing 1 are respectively connected with an end cover 1 2 and an end cover 2 4 by bolts, and a flange 3 is sleeved on the side of the casing 1 close to the end cover 1 2, a key nut 8 is arranged in the middle of the end face of the end cover 1 2, and a connecting seat 5 is fixedly connected in the middle of the end face of the end cover 2 4;

[0028] The circumferential outer wall of the end cover 2 4 near the connecting seat 5 is respectively provided with an oil and gas inlet 6 and an oil and gas outlet 7 connected to the hydraulic system oil pipe, and a dynamic preload adjustment mechanism is provided inside the casing 1 near the end cover 2 4 .

[0029] In order to achieve dynamic adjustment of bearing preload, such as Figure 5As shown, the dynamic preload adjustment mechanism includes an outlet channel 9, a transition sleeve 10, a bearing seat 11, an oil-gas gap 12 and an inlet channel 13, and the outlet channel 9 is opened in the top inner wall where the casing 1 and the end cover 4 are in contact, the outlet channel 9 is connected with the oil-gas outlet 7, and the diameter of the oil-gas outlet 7 is larger than the diameter of the outlet channel 9, and the inlet channel 13 is connected with the oil-gas inlet 6, and the diameter of the oil-gas inlet 6 is larger than the diameter of the inlet channel 13, and the transition sleeve 10 and the bearing seat 11 are mutually engaged; when the hydraulic system injects lubricating oil into the bearing seat 11, the oil enters the inlet channel 13 through the oil-gas inlet 6, and enters the inside of the bearing seat 11 through the oil-gas gap 12 above the inlet channel 13, and conversely, the oil in the bearing seat 11 flows into the outlet channel 9 through the oil-gas gap 12 at the top of the bearing seat 11, and flows out of the casing 1 through the oil-gas outlet 7.

[0030] The inlet channel 13 is opened in the bottom inner wall where the casing 1 and the end cover 4 are in contact with each other, and the transition sleeve 10 is fixedly connected to the inside of the casing 1, the bearing seat 11 is arranged in the inner circumference of the transition sleeve 10, and the oil-gas gap 12 is respectively arranged at the place where the transition sleeve 10 and the bearing seat 11 are in contact with each other.

[0031] When the electric spindle sends a low-speed rotation signal through the drive system, the hydraulic system injects a large amount of oil into the oil and gas inlet 6, and the oil enters the bearing seat 11 through the inlet channel 13. During this period, the oil pressure is measured by the pressure sensor of the hydraulic system oil pipe. Since the bearing is at a low speed, the heat generated by the bearing is small, and it is difficult to form an oil film in the oil gap between the bearing and the shaft, which increases the friction. By injecting oil into the bearing to increase the bearing preload, the bearing can better bear the load and reduce wear.

[0032] When the electric spindle receives a high-speed rotation signal through the drive system, the hydraulic system releases a certain amount of oil through the outlet channel 9, and the oil flows back into the hydraulic system through the oil and gas outlet 7. During this period, the oil pressure is measured by the pressure sensor of the hydraulic system oil pipe. At the same time, since the bearing is at a high speed, the bearing generates a lot of heat. Through the action of large centrifugal force, the oil inside the bearing forms an oil film, and the hydraulic system extracts a certain amount of oil from the bearing, which promotes the flow and dispersion of the lubricating oil in the bearing, forming a more stable and complete lubricating oil film, and the oil film is separated from the friction surface, which reduces the friction coefficient, reduces the friction force, and reduces the bearing wear. At this time, the preload in the bearing is reduced due to the extraction of hydraulic oil.

[0033] To sum up, when the electric spindle is at a low speed, the bearing generates less heat, and the bearing preload force is increased through oil and gas input. When the electric spindle is at a high speed, the bearing generates more heat, and the bearing preload force is reduced through oil and gas output. In this way, the electric spindle hydraulic damping dynamic preload adjustment function is realized, which plays a role in protecting the safety of the electric spindle inner bearing, promoting the working stability of the electric spindle inner bearing, and extending the service life of the electric spindle inner bearing.

[0034] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An electric spindle hydraulic damping dynamic preload mechanism, comprising a housing (1), characterized in that: The two ends of the casing (1) are respectively connected to an end cover 1 (2) and an end cover 2 (4) by bolts, and a flange (3) is sleeved on a side of the casing (1) close to the end cover 1 (2), a key nut (8) is arranged in the middle of the end surface of the end cover 1 (2), a connecting seat (5) is fixedly connected in the middle of the end surface of the end cover 2 (4), and a dynamic preload adjustment mechanism is arranged inside a side of the casing (1) close to the end cover 2 (4); The circumferential outer wall of the second end cover (4) close to the circumferential side of the connecting seat (5) is respectively provided with an oil and gas inlet (6) and an oil and gas outlet (7) connected to the oil pipe of the hydraulic system.

2. The electric spindle hydraulic damping dynamic preload mechanism according to claim 1 is characterized in that: The dynamic preload adjustment mechanism comprises an outlet channel (9), a transition sleeve (10), a bearing seat (11), an oil-gas gap (12) and an inlet channel (13), and the outlet channel (9) is opened in the top inner wall where the casing (1) and the second end cover (4) are in contact.

3. The electric spindle hydraulic damping dynamic preload mechanism according to claim 2 is characterized in that: The inlet channel (13) is opened in the bottom inner wall where the casing (1) and the second end cover (4) are in contact with each other, and the transition sleeve (10) is fixedly connected to the inside of the casing (1).

4. The electric spindle hydraulic damping dynamic preload mechanism according to claim 2, characterized in that: The bearing seat (11) is arranged in the inner circumference of the transition sleeve (10), and the oil-gas gap (12) is respectively arranged at the joints between the transition sleeve (10) and the bearing seat (11).

5. The electric spindle hydraulic damping dynamic preload mechanism according to claim 2, characterized in that: The outlet channel (9) is connected to the oil and gas outlet (7), and the diameter of the oil and gas outlet (7) is larger than the diameter of the outlet channel (9).

6. The electric spindle hydraulic damping dynamic preload mechanism according to claim 2, characterized in that: The inlet channel (13) is connected to the oil and gas inlet (6), and the diameter of the oil and gas inlet (6) is larger than the diameter of the inlet channel (13).

7. The electric spindle hydraulic damping dynamic preload mechanism according to claim 1, characterized in that: The transition sleeve (10) and the bearing seat (11) are mutually clamped.

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