Automatically adjustable tailstock with adjusting clamping force and machine tool equipped with it

Abstract

The present invention discloses a tailstock capable of automatically adjusting the top tightening force and a machine tool having the same, which relates to the technical field of mechanical processing and is used for adjusting the top tightening force applied to a workpiece in real time, and comprises: a seat body provided with a transmission rod and a telescopic shaft connected in a transmission manner, and a top is installed at one end of the telescopic shaft; a force sensor provided between the transmission rod and the telescopic shaft and connected to the transmission rod and the telescopic shaft respectively, and used for obtaining the real-time top tightening force of the top; a programmable logic controller electrically connecting the force sensor and the seat body, and used for determining the theoretical top tightening force applied by the transmission rod according to the acquired aspect ratio of the workpiece, and adjusting the transmission rod to apply the theoretical top tightening force. The tailstock capable of automatically adjusting the top tightening force and the machine tool having the same of the present invention can automatically adjust the top tightening force applied to the workpiece by the tailstock according to the change of the aspect ratio of the workpiece during the processing, thereby improving the qualified rate of the workpiece processing.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical processing, and relates to a tailstock capable of automatically adjusting the top tightening force and a machine tool having the tailstock. Background Art

[0002] With the development of science and technology and market competition, the precision of mechanical processing is becoming increasingly demanding, and the precision of the parts that make up the machinery is also increasing. Manufacturers use machine tools to process parts to ensure the precision of the parts. Among them, the tailstock of the machine tool uses its top to tighten the workpiece when processing shaft parts to ensure the stability of the processing. It is necessary to install a top extension on the tailstock spindle to tighten the workpiece, or to use a clamping mechanism to clamp the workpiece to achieve the positioning of the workpiece and ensure the stability of the processing. The operation of tightening or loosening the workpiece with the top is usually controlled by a hydraulic cylinder.

[0003] In the related art, when a machine tool processes a workpiece with a larger aspect ratio, it generally uses a chuck at one end to clamp it and a top at the other end to press the workpiece for processing. After the tailstock of the machine tool presses the workpiece, the pressing force on the workpiece is a constant value. However, during the workpiece processing, the aspect ratio is constantly changing. When the aspect ratio changes to a certain value and the pressing force remains unchanged, the workpiece will produce a certain deflection under the action of a larger pressing force during the processing, causing the processing accuracy to exceed the tolerance range, and even causing the parts to be scrapped, increasing costs.

[0004] How to use machine tools to change the clamping force as the aspect ratio of the workpiece changes during the processing of workpieces with a larger aspect ratio to ensure the processing accuracy of the workpiece has always been a key research direction for technical personnel in this field. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a tailstock and a machine tool capable of automatically adjusting the clamping force, so as to adjust the clamping force of a workpiece in real time.

[0006] According to a first aspect of the present invention, there is provided a tailstock for automatically adjusting the top tightening force, comprising: a seat body, comprising a transmission rod and a telescopic shaft in transmission connection, a center being mounted on one end of the telescopic shaft; a force sensor, arranged between the transmission rod and the telescopic shaft and respectively connected to the transmission rod and the telescopic shaft, for obtaining the real-time top tightening force of the center; a programmable logic controller, electrically connected to the force sensor and the seat body, for determining the theoretical top tightening force applied by the transmission rod according to the acquired aspect ratio of the workpiece, and adjusting the transmission rod to apply the theoretical top tightening force.

[0007] Preferably, the tightening force applied by the transmission rod to the workpiece determined by the programmable logic controller is calculated according to the following formula: F = F0 + K0 * (L n / D n) Where F is the theoretical tightening force applied by the transmission rod to the workpiece, F0 is the pre-tightening force applied by the transmission rod to the workpiece, K0 is the deformation coefficient of the workpiece, L n / D n is the aspect ratio of each section during the workpiece processing, L n is the length of each section of the workpiece, D n is the diameter of each section of the workpiece, n is a positive integer and n≥1.

[0008] In any of the above schemes, preferably, L n / D n is the maximum value of the aspect ratio of each section during the workpiece processing, L n D is the length of the section corresponding to the maximum aspect ratio of the workpiece. n It is the diameter of the section corresponding to the maximum aspect ratio of the workpiece.

[0009] In any of the above schemes, preferably, the force sensor is a columnar tension and pressure sensor, the transmission rod is threadedly connected to the force sensor, and the telescopic shaft is detachably connected to the force sensor via a screw.

[0010] In any of the above schemes, preferably, the seat body is provided with a telescopic cylinder, the telescopic cylinder is provided with a cavity with openings at both ends, the first end of the telescopic shaft is placed in the cavity and is detachably connected to the force sensor, and the second end of the telescopic shaft is detachably installed with a top point and exposed from the front end of the telescopic cylinder.

[0011] In any of the above schemes, preferably, one end of the telescopic cylinder close to the force sensor is detachably connected to a mounting plate, and the transmission rod passes through the mounting plate and is connected to the force sensor.

[0012] In any of the above schemes, preferably, the mounting plate is also detachably connected with a power component, the power component is electrically connected to the programmable logic controller, and the power component includes one of a hydraulic cylinder, a pneumatic cylinder, and a servo motor.

[0013] In any of the above schemes, it is preferred that the power component is a hydraulic cylinder, which is provided with a rear oil hole and a front oil hole, and the transmission rod is driven to reciprocate along the axis direction of the cavity by supplying and releasing oil through the rear oil hole and the front oil hole.

[0014] In any of the above schemes, preferably, the tailstock for automatically adjusting the tightening force also includes a base and a fixing member, wherein the seat body and the base are detachably connected, and the base and the fixing member are movably connected; the base is provided with a track groove, and the fixing member is movably connected to the base near the track groove.

[0015] According to a second aspect of the present invention, there is provided a machine tool, comprising: a base, provided with a tailstock track, the tailstock track being movably connected to a tailstock for automatically adjusting the top tightening force as in the first aspect and any one of the preferred embodiments; a chuck, fixed to the base, for fixing the end of a workpiece; a numerical control system, electrically connected to a programmable logic controller and a force sensor of the tailstock for automatically adjusting the top tightening force, and correcting the real-time top tightening force of the tailstock for automatically adjusting the top tightening force based on obtaining the theoretical top tightening force of the programmable logic controller and the real-time top tightening force of the force sensor.

[0016] Through the above design, the present invention can at least achieve the following beneficial effects:

[0017] The tailstock and machine tool for automatically adjusting the top tightening force of the present invention obtain the real-time top tightening force of the workpiece by arranging a force sensor between the transmission rod and the telescopic shaft; obtain the theoretical top tightening force of the workpiece by determining the aspect ratio data of the part of the workpiece that has been processed during the processing; the programmable logic controller adjusts the real-time top tightening force applied by the tailstock according to the theoretical top tightening force, thereby avoiding damage to the workpiece structure caused by the top tightening force applied by the tailstock to the workpiece remaining unchanged, and improving the qualified rate of workpiece processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of an embodiment of a tailstock for automatically adjusting the top tightening force of the present invention;

[0019] Figure 2 AA cross-sectional structural diagram of another embodiment of the tailstock for automatically adjusting the top tightening force of the present invention;

[0020] Figure 3 It is a structural schematic diagram of an embodiment of a machine tool of the present invention;

[0021] Figure 4 It is a connection diagram of the partial structure of another embodiment of the machine tool of the present invention.

[0022] Description of the numbers in the figure:

[0023] 1-base; 11-transmission rod; 12-telescopic shaft; 121-first end; 122-second end; 13-top; 14-telescopic cylinder; 141-cavity; 2-force sensor; 3-programmable logic controller; 4-mounting plate; 5-power piece; 51-rear oil hole; 52-front oil hole; 6-base; 61-track groove; 7-fixing piece; 10-base; 20-chuck; 30-workpiece; 40-CNC system. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] In addition, in the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be directly connected or indirectly connected through an intermediate component. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0026] The embodiment of the present invention aims to solve the technical problems existing in the above-mentioned related technologies and provide a tailstock that automatically adjusts the clamping force according to the aspect ratio of the workpiece. In actual operation, when turning workpieces such as stepped shafts, a cylindrical blank is generally clamped on the tailstock of a machine tool and a tool head is used for turning. During the turning process, the diameter of the blank is changed along its axial direction, and finally the desired stepped shaft workpiece is processed. In the related technology, the clamping force applied to the blank is a fixed value. During the processing, the local diameter of the blank is reduced, so that the clamping force that can be borne by the part without deformation is reduced, causing the part with reduced diameter to deform, affecting the quality of the workpiece finally processed and formed.

[0027] According to the process of the present invention, the aspect ratio L of the blank is n / D n The value of determines the maximum tightening force F that the blank can withstand without deformation, where L n The diameter of the stepped shaft is D n The length of the part along the axis of the blank, D n For example, the length of a stepped shaft is L. During the processing of a blank of length L, the blank is turned into segments of different diameters by the cutter head of the machine tool along the axial direction. The number of segments with different diameters is 1, 2, 3...n, n+1, n+2..., then L=L1+L2+L3+...L n +L n+1 +L n+2 ..., adjacent segments are connected as a whole, and the nth segment can be the segment corresponding to the maximum aspect ratio among all the processed segments. n / D n The value of can change during the blank processing. The blank diameter is the same. After processing n-1 sections, the maximum length-to-diameter ratio of the blank may be L n-1 / D n-1 , then L n-1 / D n-1 As the length-to-diameter ratio for calculating the theoretical tightening force. When starting to process the nth section, Ln-1 / D n-1 As the length-to-diameter ratio for calculating the theoretical tightening force, as the length of the nth segment increases, L n / D n The value of will increase as the turning process of the nth segment progresses, for example, L n More than L n-1 or D n When the value of L n / D n The value is greater than L n-1 / D n-1 , then L n / D n As the length-to-diameter ratio for calculating the theoretical tightening force. n , L n It can be the coordinate data of the tool head obtained from the CNC system of the machine tool, D n It can be the value of the x-axis, L n It can be determined by the value of the z-axis. For example, if the end of the blank is placed at the zero point of the z-axis in the coordinate system, the length value L1 of the first segment can be the absolute value of the z-axis value. When processing the nth segment, the z value of the position of the tool head minus the z value of the position of the tool head at the end of the n-1th segment can be used. The absolute value of the difference between the two is the length of the current processing segment. If the lengths of each segment in the coordinate system can be recorded as Z1, Z2, Z3...Z n , Z n+1 ...and other values, the total length can be L = Z1 + Z2 + Z3 ... Z n +Z n+1 ….

[0028] Since the stepped shaft workpiece is composed of multiple sections, each section has a different diameter and may also have a different length. Therefore, in the process of machining the workpiece, the value of the real-time tightening force applied to the blank in the embodiment of the present invention can be the minimum value of the maximum tightening force that can be borne by the above sections, and the minimum value can change in real time with the machining process. For example, a stepped shaft is composed of three sections with different diameters. According to the aspect ratio L n / D n The calculation shows that the maximum tightening force that the first section of the stepped shaft of this material can withstand is 1000N, the maximum tightening force that the second section can withstand is 900N, and the maximum tightening force that the third section can withstand is 950N. After turning the first section, the second section of the blank is processed. During this process, the tightening force on the blank needs to be gradually reduced to 900N as the second section is processed. Processing the third section alone can increase the tightening force applied to the blank to 950N, but the blank is an integrated structure. Considering that exceeding 900N will cause the second section to be deformed, the final tightening force applied to the blank is still maintained at 900N. The tailstock for automatically adjusting the tightening force of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings.

[0029] Figure 1 It is a structural schematic diagram of an embodiment of a tailstock for automatically adjusting the top tightening force of the present invention; Figure 2 FIG. 2 is a schematic diagram of the AA cross-sectional structure of another embodiment of the tailstock of the present invention which automatically adjusts the top tightening force. Figure 1 and Figure 2 As shown, the tailstock for automatically adjusting the top tightening force of this embodiment may include a seat body 1, a force sensor 2 and a programmable logic controller 3, wherein the seat body 1 may include a transmission rod 11 and a telescopic shaft 12 in transmission connection, and a top 13 is installed at one end of the telescopic shaft 12. The force sensor 2 may be arranged between the transmission rod 11 and the telescopic shaft 12, and respectively connect the transmission rod 11 and the telescopic shaft 12, so as to obtain the real-time top tightening force of the top 13. The programmable logic controller 3 may electrically connect the force sensor 2 and the seat body 1, so as to determine the theoretical top tightening force applied by the transmission rod 11 according to the acquired aspect ratio of the workpiece 30, and adjust the transmission rod 11 to apply the theoretical top tightening force.

[0030] In this embodiment, the tip 13 acts on one end of the elongated workpiece 30 to be processed, and presses the workpiece 30 against the machine tool to ensure that the central axis of the workpiece 30 does not move during the processing of the workpiece 30. The magnitude of the real-time pressing force applied to the workpiece 30 can be measured by the force sensor 2. During the processing of the workpiece 30, the diameter of the workpiece 30 or the partial diameter of the workpiece 30 decreases due to the turning operation. If the magnitude of the pressing force applied by the tip 13 to the workpiece 30 remains unchanged, the workpiece 30 is likely to deform at the position where the diameter decreases. In this embodiment, by obtaining the diameter size of each position of the workpiece 30 along its axial direction and the length of the workpiece 30 and other data, the aspect ratio of each position along the axial direction of the workpiece 30 is calculated, and the maximum pressing force that each position along the axial direction of the workpiece 30 can bear is determined as the theoretical pressing force according to the aspect ratio. In addition, the theoretical pressing force is the minimum value of the maximum pressing force that each position along the axial direction of the workpiece 30 can bear, so as to ensure that each position of the workpiece 30 does not deform under the action of the theoretical pressing force, and ensure the qualified rate of the workpiece 30 processing.

[0031] The transmission rod 11, the telescopic shaft 12, the force sensor 2 and the top 13 are coaxially arranged, which can improve the accuracy of the real-time clamping force obtained by the force sensor 2. The real-time clamping force is equal to the clamping force transmitted to the top 13 through the transmission rod 11 and the telescopic shaft 12. If the force transmission is not coaxial, deviation is likely to occur, and the clamping force applied by the top 13 to the workpiece 30 is smaller than the real-time clamping force measured by the force sensor 2, which is likely to cause radial position deviation during the turning process of the workpiece 30 due to the small clamping force of the top 13 actually applied to the workpiece 30, affecting the machining accuracy of the workpiece 30, and even making the workpiece 30 scrapped.

[0032] In this embodiment, the tailstock top tightening force formula model can be edited or input in the programmable logic controller 3 (PLC) to determine the theoretical top tightening force applied by the top 13 to the workpiece 30, so as to achieve different top tightening forces when processing the workpiece 30 with different aspect ratios. During the processing of the workpiece 30, the programmable logic controller 3 can automatically obtain the length and height values ​​of the workpiece 30, and the height value can be data such as the diameter or radius of the workpiece 30, and the acquisition method can be that the programmable logic controller 3 calculates the coordinate value of the turning tool in the numerical control system 40 of the machine tool. The programmable logic controller 3 can be an interface connected to the numerical control system 40 of the machine tool by a plug-in, and the length and diameter of the blank at the turning position are determined by obtaining the tool head coordinate data. The programmable logic controller 3 is electrically connected to the force sensor 2 and the power member 5, obtains the actual top tightening force measured by the force sensor 2, and compares it with the theoretical top tightening force, and adjusts the power member 5 according to the comparison result, so that the actual top tightening force applied by the power member 5 is adjusted to be equal to the theoretical top tightening force.

[0033] In some embodiments, the tightening force applied by the transmission rod to the workpiece 30 determined by the programmable logic controller 3 can be calculated according to the following formula: F = F0 + K0 * (L n / D n ) Wherein, F is the theoretical tightening force applied by the transmission rod to the workpiece 30, F0 is the pre-tightening force applied by the transmission rod to the workpiece 30, K0 is the deformation coefficient of the workpiece 30, L n / D n is the maximum value of the aspect ratio of each section during the machining of the workpiece 30, L n D is the length of the section corresponding to the maximum aspect ratio of the workpiece. n is the diameter of the section corresponding to the maximum aspect ratio of the workpiece, n is a positive integer and n≥1. The above deformation coefficient can be compared with the aspect ratio L of each section of the workpiece 30. n / D n Inversely proportional, that is, L n / D n The larger the value of K0*(L n / D n ) The smaller the value calculated, K0 can be determined based on the material of the workpiece 30 and the aspect ratio of the part of the workpiece that has been processed. The preload force F0 applied to the workpiece 30 can ensure that the workpiece 30 will not fall off the machine tool. The specific value can be determined according to the workpiece 30 of different materials and different sizes, and this embodiment is not specifically limited here. The programmable logic controller 3 is electrically connected to the power part 5 of the seat body 1 to adjust the preload force according to the L during the processing of the blank. n / D n The actual tightening force applied by the power member 5 is adjusted to be equal to the theoretical tightening force value.

[0034] In some embodiments, the force sensor 2 is a columnar tension and pressure sensor, the transmission rod 11 is threadedly connected to the force sensor 2, and the telescopic shaft 12 is detachably connected to the force sensor 2 by screws. The columnar tension and pressure sensor uses an elastic body as an intermediary, and the force acts on the resistors on both sides of the sensor to change its resistance, which is then converted into an electrical signal through a corresponding circuit. It has high accuracy, a wide measurement range, a long service life, a simple structure, and good frequency response characteristics. In this embodiment, the way in which the transmission rod 11 and the telescopic shaft 12 are connected to the force sensor 2 can also be interchanged, the purpose of which is to ensure that the transmission rod 11, the telescopic shaft 12 and the force sensor 2 avoid axial displacement, thereby affecting the measurement accuracy of the force sensor 2. In addition, the transmission rod 11 is threadedly connected to the force sensor 2, and the telescopic shaft 12 is detachably connected to the force sensor 2 by screws, so that the transmission rod 11 or the telescopic shaft 12 or the force sensor 2 can be easily replaced, so that any of the structures can be replaced separately after damage, thereby reducing the maintenance cost of the tailstock of the automatic tightening force adjustment of this embodiment.

[0035] Furthermore, in some embodiments, Figure 2 As shown, the base body 1 is provided with a telescopic cylinder 14, and the telescopic cylinder 14 is provided with a cavity 141 with openings at both ends, the first end 121 of the telescopic shaft 12 is placed in the cavity 141 and detachably connected to the force sensor 2, and the second end 122 of the telescopic shaft 12 is detachably mounted with a tip 13 and exposed from the front end of the telescopic cylinder 14. In this embodiment, the diameter of the cavity 141 of the telescopic cylinder 14 can be the same as the diameter of the telescopic shaft 12, further ensuring that the telescopic shaft 12 can only move along the axial direction of the telescopic shaft 12, avoiding inaccurate measurement results of the force sensor 2 caused by displacement in the radial direction, and can play a certain protective role on the force sensor 2, avoiding pollution and structural damage to the force sensor 2 caused by external impact.

[0036] In some embodiments, the end of the telescopic cylinder 14 close to the force sensor 2 is detachably connected to the mounting plate 4, and the transmission rod 11 passes through the mounting plate 4 and is connected to the force sensor 2; the mounting plate 4 is also detachably connected to the power member 5, and the power member 5 is electrically connected to the programmable logic controller 3, and the power member 5 may include one of a hydraulic cylinder, a pneumatic cylinder, and a servo motor. Specifically, the programmable logic controller 3 can be electrically connected to the controller of the hydraulic cylinder or the controller of the pneumatic cylinder or the controller of the servo motor. In this embodiment, the power member 5, as a part of the seat body 1, can be detachably fixed on the mounting plate 4, provide power for the transmission rod 11, generate a tightening force on the force sensor 2, and then transmit it to the top 13 to tighten the workpiece 30. The transmission rod 11 can pass through the mounting plate 4 and extend into the above-mentioned cavity 141 to connect to the force sensor 2. A sealing ring can also be set on the mounting plate 4 to seal the part of the transmission rod 11 passing through the mounting plate 4 to prevent external pollution from entering the cavity 141.

[0037] The type of the power member 5 in this embodiment can be selected according to actual needs, and this embodiment does not specifically limit it. The power member 5 is a hydraulic cylinder, which is provided with a rear oil hole 51 and a front oil hole 52. The rear oil hole 51 and the front oil hole 52 cooperate to supply and discharge oil to drive the transmission rod 11 to reciprocate along the axis direction of the cavity 141. Specifically, Figure 2 As shown, oil can be injected into the hydraulic cylinder through the rear oil hole 51. By continuously injecting oil, the space occupied by the hydraulic oil at the left end of the hydraulic cylinder gradually increases, thereby pushing the transmission rod 11 to move the clamping force sensor 2 to the right, and transmitting the clamping force to the top 13 to clamp the workpiece 30. Similarly, it is applicable to the cylinder. The power part 5 can also be selected as a servo motor. The servo motor can realize closed-loop control of position, speed and torque, has good high-speed performance, strong overload resistance, stable performance, and is suitable for occasions with high-speed response requirements. The dynamic response time of acceleration and deceleration is short and the noise is low.

[0038] In some embodiments, the tailstock for automatically adjusting the tightening force further includes a base 6 and a fixing member 7, wherein the base body 1 is detachably connected to the base 6, and the base 6 is movably connected to the fixing member 7; the base 6 is provided with a track groove 61, and the fixing member 7 is movably connected to the base 6 near the track groove 61. In this embodiment, the base body 1 can be detachably connected to the base 6, specifically, it can be connected by bolts and nuts, or it can be detachably connected by connecting members such as screws and pins, and this embodiment is not specifically limited here. In this embodiment, the base body 1 and the base 6 are set to be detachably connected, and different bases 6 can be configured according to different installation environments, such as height and installation angle, so that the base body 1 can be installed on different machine tools or other equipment to achieve the operation of tightening the workpiece 30.

[0039] Furthermore, by setting a track groove 61 on the base 6 and configuring a fixing member 7 for the base 6, the base 6 can be installed along the set track, and the base 6 can be fastened and installed on the target machine tool or equipment through the fixing member 7, thereby improving the stability of the tailstock fixation of the automatic adjustment of the clamping force in this embodiment, thereby improving the processing accuracy of the workpiece 30 and the qualified rate of the workpiece 30.

[0040] Based on the same or similar design concept, a second aspect of an embodiment of the present invention provides a machine tool. Figure 3 It is a structural schematic diagram of an embodiment of a machine tool of the present invention; Figure 4 FIG. 1 is a schematic diagram of the connection of the partial structure of another embodiment of the machine tool of the present invention. Figure 3 and Figure 4 , and combined with Figure 1 and Figure 2The machine tool of this embodiment may include a base 10, a chuck 20 and a numerical control system 40, wherein the base 10 may be provided with a tailstock track 11, and the tailstock track 11 is movably connected with a tailstock for automatically adjusting the top tightening force as in any one of the first aspect and each preferred embodiment described above. The chuck 20 may be fixed to the base 10 to fix the end of the workpiece 30; the numerical control system 40 may be electrically connected to the programmable logic controller 3 and the force sensor 2 of the tailstock for automatically adjusting the top tightening force, and based on obtaining the theoretical top tightening force of the programmable logic controller 3 and the real-time top tightening force of the force sensor 2, the real-time top tightening force of the tailstock for automatically adjusting the top tightening force is corrected.

[0041] Before machining the workpiece 30, the tailstock with automatic adjustment of the tightening force is installed on the tailstock guide rail of the machine tool of this embodiment through the track groove 61 of the base 6. After the base 6 is adjusted to a specified position along the tailstock guide rail, the screws provided on the fixing member 7 are tightened to lock the base 6 on the tailstock guide rail of the machine tool. Figure 3 As shown, the left end of the workpiece 30 is clamped by the component chuck 20, and the right end is tightened by the component top 13. The top 13 is installed on the telescopic shaft 12, and the telescopic shaft 12 is connected to the force sensor 2 of the columnar tension and pressure sensor by screws. The columnar tension and pressure sensor is threadedly connected to the right end of the transmission rod 11, the mounting plate 4 connects the power component 5 and the telescopic cylinder 14, and the rear oil hole 51 and the front oil hole 52 are connected to the oil circuit, thereby driving the transmission rod 11. Since the columnar tension and pressure sensor is between the component transmission rod 11 and the telescopic shaft 12, it can measure the real-time tightening force of the top.

[0042] By installing a column-type tension and pressure sensor between the transmission rod 11 and the telescopic shaft 12 and connecting it to the numerical control system 40 connected to PLC3 and the machine tool, the data can be displayed on the system panel of the numerical control system 40, and the real-time tightening force and the theoretical tightening force determined by PLC3 can be displayed in real time on the button interface reserved for the numerical control system 40. By comparing the real-time tightening force measured by the force sensor 2 displayed in real time and the theoretical tightening force calculated by the preset program model in PLC3, it is possible to realize real-time correction of the real-time tightening force value applied by the power part 5 to the transmission rod 11 and transmitted to the top 13 through the force sensor 2 and the telescopic shaft 12, thereby improving the qualification rate of the workpiece 30 processed by the machine tool of this embodiment.

[0043] It is known from common technical knowledge that the present invention can be implemented by other embodiments that do not deviate from its essence or essential features. Therefore, the above disclosed embodiments are only illustrative in all respects and are not exclusive. All changes within the scope of the present invention or within the scope equivalent to the present invention are included in the present invention.

Claims

1. A tailstock with automatic adjustment of the tightening force, characterized in that: include: The seat body (1) is provided with a transmission rod (11) and a telescopic shaft (12) which are transmission-connected, and a tip (13) is installed at one end of the telescopic shaft (12); A force sensor (2) is disposed between the transmission rod (11) and the telescopic shaft (12), and is respectively connected to the transmission rod (11) and the telescopic shaft (12), and is used to obtain a real-time tightening force of the top tip (13); a programmable logic controller (3), electrically connected to the force sensor (2) and the seat body (1), and used to determine the theoretical tightening force applied by the transmission rod (11) according to the acquired aspect ratio of the workpiece, and to adjust the transmission rod (11) to apply the theoretical tightening force; The tightening force applied by the transmission rod to the workpiece, determined by the programmable logic controller (3), is calculated according to the following formula: F=F0+K0*(L n / D n ) Wherein, F is the theoretical tightening force applied by the transmission rod to the workpiece, F0 is the pre-tightening force applied by the transmission rod to the workpiece, K0 is the deformation coefficient of the workpiece, and L n / D n is the aspect ratio of each section during the workpiece processing, L n is the length of each section of the workpiece, D n is the diameter of each section of the workpiece, n is a positive integer and n≥1.

2. The tailstock for automatically adjusting the top tightening force according to claim 1, characterized in that: L n / D n is the maximum value of the aspect ratio of each section during the workpiece processing, L n D is the length of the section corresponding to the maximum aspect ratio of the workpiece. n It is the diameter of the section corresponding to the maximum aspect ratio of the workpiece.

3. The tailstock for automatically adjusting the top tightening force according to claim 1, characterized in that: The force sensor (2) is a columnar tension and pressure sensor, the transmission rod (11) is threadedly connected to the force sensor (2), and the telescopic shaft (12) is detachably connected to the force sensor (2) via a screw.

4. The tailstock for automatically adjusting the top tightening force according to any one of claims 1 to 3, characterized in that: The seat body (1) is provided with a telescopic cylinder (14), the telescopic cylinder (14) being provided with a cavity (141) with front and rear ends being open, the first end (121) of the telescopic shaft (12) being disposed in the cavity (141) and being detachably connected to the force sensor (2), and the second end (122) of the telescopic shaft (12) being detachably mounted with the tip (13) and being exposed from the front end of the telescopic cylinder (14).

5. The tailstock for automatically adjusting the top tightening force according to claim 4 is characterized in that: One end of the telescopic cylinder (14) close to the force sensor (2) is detachably connected to a mounting plate (4), and the transmission rod (11) passes through the mounting plate (4) and is connected to the force sensor (2).

6. The tailstock for automatically adjusting the top tightening force according to claim 5, characterized in that: The mounting plate (4) is also detachably connected to a power component (5), the power component (5) being electrically connected to the programmable logic controller (3), the power component (5) comprising one of a hydraulic cylinder, a pneumatic cylinder, and a servo motor.

7. The tailstock for automatically adjusting the top tightening force according to claim 6, characterized in that: The power member (5) is a hydraulic cylinder, which is provided with a rear oil hole (51) and a front oil hole (52). The rear oil hole (51) and the front oil hole (52) cooperate to supply and release oil to drive the transmission rod (11) to reciprocate along the axis of the cavity (141).

8. The tailstock for automatically adjusting the top tightening force according to any one of claims 1 to 3, characterized in that: The tailstock for automatically adjusting the tightening force further comprises a base (6) and a fixing member (7), wherein: The seat body (1) is detachably connected to the base (6), and the base (6) is movably connected to the fixing member (7); The base (6) is provided with a track groove (61), and the fixing member (7) is movably connected to the base (6) near the track groove (61).

9. A machine tool, characterized in that: include: A base (10) is provided with a tailstock track, wherein the tailstock track is movably connected to a tailstock with automatic adjustment of the tightening force as claimed in any one of claims 1 to 8; A chuck (20) fixed to the base (10) and used to fix an end of a workpiece; A numerical control system (40) is electrically connected to a programmable logic controller (3) and a force sensor (2) of the tailstock for automatically adjusting the pressing force, and corrects the real-time pressing force of the tailstock for automatically adjusting the pressing force based on the theoretical pressing force of the programmable logic controller (3) and the real-time pressing force of the force sensor (2).

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