JP2009214276A - Cylindrical grinding machine and cylindrical grinding method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a cylindrical grinding method capable of selectably switching a center support structure of a workpiece to a dead center system and a live center system, superior in general-purpose properties, and significantly shortening the cycle time with high precision. <P>SOLUTION: A spindle center 10 is rotatably pivoted by a spindle head 1 and is connected and driven with/by a drive motor 13, being a spindle rotation drive source, and a workpiece rotation part 11 is provided for driving workpiece W to rotate. A tailstock center 20 is rotatably pivoted by a tailstock 2 and connected and driven with/by the drive motor 24, and a tailstock pressure adjustment part 21 is provided for adjusting a tailstock pressure in an axial direction of the tailstock 2. Both centers 10 and 20 are designed to function as a live center or a dead center automatically and selectively, thereby developing a cylindrical grinding method superior in general-purpose properties and capable of significantly shortening the cycle time with high precision. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a cylindrical grinder and a grinding method thereof, and more specifically, a cylindrical grinder having a center structure that switches and changes a support state of a cylindrical workpiece according to grinding processing conditions, and a cylindrical grinding method using the cylindrical grinder About.

  A cylindrical grinder is the most common grinder that supports the axial positions of both ends of a cylindrical workpiece (hereinafter referred to as a workpiece) and grinds the outer diameter surface of the workpiece. A headstock having a spindle center for supporting the shaft center position, a tailstock having a tailstock center for supporting the shaft center position of the other end of the work, and a cylinder of the work supported by the center and the tailstock. A grinding wheel with a grinding wheel that grinds the outer diameter surface, and is configured to grind the outer diameter surface of the workpiece with a grinding wheel that rotates at a high speed while rotating the workpiece at a low speed. Traverse grinding that grinds the workpiece outer diameter surface with a grinding wheel while traversing the car in the workpiece axis direction, and plunge cut grinding that cuts the grinding wheel against the workpiece and grinds the workpiece outer diameter surface Done

  By the way, as a center support method of the workpiece in this cylindrical grinding, (a) a so-called dead center or fixed center system in which the spindle center and the tailstock center are fixed in a non-rotatable manner and the workpiece is rotationally driven, (b) the above In the so-called live center or rotation center system in which the spindle center and the tailstock center are rotatable and these centers are driven to rotate together with the workpiece, (c) in the dead center system, the spindle center and the core fixed in a non-rotatable manner. There are methods in which the push center can be replaced with a rotatable spindle center and a tailstock center, but each has the following problems.

(A) In the dead center system, since the spindle center and the tailstock center do not rotate, it is difficult for the workpiece to run out and high grinding accuracy can be expected. Rotation is likely to generate heat and wear on the support portion, which makes it impossible to increase the tailstock load on the workpiece and to perform heavy cutting (grinding) processing.

(B) In the live center method, contrary to the dead center method, the spindle center and the tailstock center rotate, so there is no heat generation or wear between the workpiece and heavy cutting (grinding) processing. On the other hand, the rotational blurring between the spindle center and the tailstock center tends to induce runout of the workpiece, and therefore high grinding accuracy cannot be expected.

(C) In the dead center method, if the live center method can be adopted by recombination, time and labor are required for recombination work, and workability is very poor.

  In this regard, as described in Patent Document 1, cylindrical grinding having a structure in which the tailstock center of the tailstock is selectively switched between a non-rotating dead center and a rotatable live center. A board has also been developed and proposed.

  However, the live center in this cylindrical grinder is a type in which the tailstock center of the tailstock is freely rotatable and is rotated by the spindle center of the headstock and further the rotation of the workpiece. Relative rotation may occur, and the live load and the dead center have the same tailstock load on the workpiece, which is not sufficient because of the following problems: There wasn't.

That is, if the tailstock load is large and high, there will be a problem that the center support will generate heat and wear at the dead center. On the other hand, if the tailstock load is small and light, the center will be Insufficient support rigidity between workpieces, high load cannot be applied during processing, and heavy cutting (grinding) processing cannot be performed.
JP 2000-246504 A

  The present invention has been made in view of such conventional problems, and an object thereof is to selectively switch the center support configuration of a workpiece in cylindrical grinding between a dead center method and a live center method. An object of the present invention is to provide a cylindrical grinding machine that has a configuration capable of being used, is versatile, and can realize cylindrical grinding with high accuracy and greatly reduced cycle time.

  Another object of the present invention is to provide a cylindrical grinding method capable of performing efficient cylindrical grinding with high accuracy, a short cycle time, and high efficiency by the above cylindrical grinding machine.

  In order to achieve the above object, the cylindrical grinding machine of the present invention supports the axial positions of both ends of the workpiece and grinds the outer diameter surface of the workpiece, and supports the axial position of one end of the workpiece. Grinding the spindle outer surface having a spindle center, the tailstock having a tailstock center for supporting the center position of the other end of the workpiece, and the cylindrical outer diameter surface of the workpiece supported by the spindlestock and the tailstock. A grinding wheel platform including a grinding wheel, wherein the spindle center is rotatably supported and connected to a spindle rotation driving source, and a workpiece rotating means for rotating the workpiece is provided. In the tailstock, the tailstock center is rotatably supported and connected to the tailstock shaft rotation drive source, and a tail pressure adjusting means for adjusting a tailstock pressure in the axial direction of the tailstock. Provided above main The center and the tailstock center are selectively configured to function as a live center that supports the workpiece while rotating and driving in synchronization with each other, or as a dead center that supports the workpiece in a state where the rotation is stopped. It is characterized by that.

As a preferred embodiment, the configurations listed below can be adopted.
(1) A control means for controlling the headstock, the tailstock, and the drive source in the headstock in conjunction with each other is provided. The control means synchronizes the spindle center and the tailstock center with each other during heavy grinding. In addition to functioning as the live center that supports the workpiece while rotating, the spindle center and the tailstock center function as the dead center that supports the workpiece while the spindle center and the tailstock center stop rotating during finish grinding. The drive source is controlled.

(2) The workpiece rotating means is a scraping drive device that rotationally drives the workpiece via a scrape attached to an end of the workpiece on the headstock side.

(3) The tail pressing adjustment means is configured to switch and adjust the axial centering load of the tailstock center in the tailstock between heavy grinding and finish grinding.

(4) The center pressing adjustment means includes a center pressing adjusting spring and a hydraulic cylinder that press the tail center against the tailstock in the axial direction, and the center pressing adjusting spring includes the finish grinding. At the same time, the tailstock center is elastically biased with a predetermined pressure in the axial direction, and the hydraulic cylinder biases the tailstock center with a predetermined pressure in the axial direction during heavy grinding. It is supposed to be configured.

(5) The center pressing adjustment spring constantly elastically urges the center pressing center in the axial direction with a predetermined pressure, and the hydraulic cylinder is configured to release the center pressing adjustment spring during the heavy grinding. In cooperation with the biasing action, the tailstock center is additionally biased with a predetermined pressure in the axial direction.

(6) In the hydraulic cylinder, the spindle center and the tailstock center are rotationally driven in synchronization with each other by the control means for controlling the spindle stock, the tailstock and the drive source in the spindle stock in conjunction with each other. However, it operates when functioning as a live center for supporting the workpiece, and urges the tailstock center with a predetermined pressure in the axial direction so that the spindle center and the tailstock center stop rotating. Deactivates when functioning as a supporting dead center.

(7) In the tailstock, the tailstock is rotatably supported by the tailstock housing and is movable in the axial direction, and the tailstock center is coaxially removed from the tip of the tailstock. The tailstock shaft is drive-coupled to the tailstock shaft rotation drive source, the tailstock shaft rotation drive source is electrically connected to the control means, and the rear end of the tailstock shaft The centering pressure adjusting spring for pressing the tailstock shaft axially forward with respect to the tailstock housing is provided at a portion, and the tailstock shaft is disposed on the outer periphery of the tailstock shaft. The hydraulic cylinder for reciprocating in the axial direction with respect to the hydraulic cylinder is provided, and the hydraulic source of the hydraulic supply device for reciprocating the piston of the hydraulic cylinder in the front-rear direction and the pressure oil control valve are electrically connected to the control means. Yes.

(8) The tailstock is supported by the tailstock housing so as to be rotatable and movable in the axial direction via a hydrostatic bearing.

(9) The mounting structure of the two centers in the headstock and the tailstock is provided with a tapered shank hole and a mounting end surface at the tip of the rotatable rotating shaft, respectively. Is configured such that either one of the taper fitting mounting structure using the taper shank hole and the end surface mounting structure using the mounting end surface can be selectively employed.

  The first cylindrical grinding method of the present invention is a cylindrical grinding method in which the cylindrical centering machine supports the axial positions of both ends of the workpiece and grinds the outer diameter surface of the workpiece. Using the tailstock center as a live center, the outer diameter surface of the workpiece is heavily ground by the grinding wheel.

  Further, the second cylindrical grinding method of the present invention is a cylindrical grinding method for grinding the outer diameter surface of the workpiece while supporting the axial center positions of both ends of the workpiece by the cylindrical grinding machine. In addition, the outer diameter surface of the workpiece is finish-grinded by the grinding wheel using the tailstock center as a dead center.

  Further, the third cylindrical grinding method of the present invention is a cylindrical grinding method for grinding the outer diameter surface of the work by supporting the axial positions of both ends of the work by the same cylindrical grinding machine, and the spindle center. After the outer diameter surface of the workpiece is heavily ground by the grinding wheel using the grinding wheel as a live center, the outer diameter surface of the workpiece is finished by the grinding wheel using the spindle center and the tailstock center as a dead center. It is characterized by grinding.

  As a preferred embodiment, prior to the heavy grinding, the spindle center and the tailstock center are used as a live center, and both the centers are subjected to in-machine grinding by the grinding wheel so as to prevent live shake of these centers. .

  According to the cylindrical grinding machine of the present invention, a spindle stock having a spindle center for supporting the axial center position of one end of the workpiece, a tailstock having a tailstock center for supporting the axial center position of the other end of the workpiece, and these And a grinding wheel head including a grinding wheel for grinding a cylindrical outer diameter surface of a work supported by the spindle table and the tailstock. In the spindle table, the spindle center is rotatably supported and driven to rotate the spindle. And a work rotating means for driving the work to rotate. In the tailstock, the tailstock center is rotatably supported and connected to a tailstock rotation driving source. A tail pressing adjustment means for adjusting a tail pressing force (tail pressing load) in the axial direction of the tailstock is provided, and the spindle center and the tailstock center are selectively rotated in synchronization with each other. Set the work It is configured to function as a live center that supports the workpiece or as a dead center that supports the workpiece in a state where the rotation is stopped, so that the effects listed below are obtained, versatility, and high accuracy. It is possible to provide a cylindrical grinder capable of realizing cylindrical grinding with a significantly shortened cycle time.

(1) Since the spindle center of the headstock and the tailstock of the tailstock can be selectively switched as a live center or a dead center, it is called heavy grinding and finish grinding with a single cylindrical grinder. Grinding with different processing conditions can be executed.

  In other words, in the live center system in which the spindle center and the tailstock of the tailstock function as a live center, the spindle center and the tailstock center rotate, and there is no generation of heat and wear between the workpiece that supports the center. This makes it possible to perform heavy grinding with high rigidity and high load support and a large cutting amount and a large grinding load. On the other hand, the spindle center and the tailstock of the tailstock function as a dead center. In the center system, the spindle center and tailstock center are non-rotating, so there is no center runout during center rotation due to the assembly accuracy of these centers, and this causes center runout in the workpiece that supports the center. It is difficult to perform finish grinding that requires high grinding accuracy.

(2) Since the spindle center of the headstock and the tailstock of the tailstock can be selectively switched as a live center or a dead center by a simple switching operation, conventional time and labor are required. This eliminates the need for center rework with poor workability, and enables efficient switching between heavy grinding and finish grinding.

  For example, the spindle head, the tailstock, and the control means for controlling the driving source in the headstock in conjunction with each other are provided, and the spindle center and the tailstock center function as a live center and a dead center by automatic switching by the control means. By controlling in this way, it is possible to automatically switch between a live center and a dead center within a series of cylindrical grinding cycles, and it is possible to perform cylindrical grinding with high accuracy and greatly shortening the cycle time.

(3) Since the spindle center and the tailstock center can be switched from the live center to the dead center while maintaining the center support state of the work, the center of the work does not shift due to the change of the center support method. From this point, high grinding accuracy can be obtained.

(4) Since both the spindle center and the tailstock center as a live center are driven to rotate positively and synchronously by a rotation drive source, relative rotation can occur between the workpiece and the center. Therefore, it is possible to effectively and reliably avoid the generation of heat and wear at the center support portion.

(5) Since a tail pressing adjustment means is provided to adjust the tailstock pressure (tailstock load) in the axial direction of the tailstock, the tailstock load on the work as a live center or dead center is set to an optimum value. As a result, there is a problem that the tailstock load becomes large and high at the dead center, and heat develops and wears at the center support part, or the tailstock load is small and light at the live center. Thus, the occurrence of problems such as insufficient support rigidity between the center and the workpiece is effectively prevented.

  Further, according to the cylindrical grinding method of the present invention using the cylindrical grinder, the main spindle center and the tailstock center are used as a live center for heavy grinding of the outer surface of the workpiece, and the spindle center and the tailstock center are dead. As the center, the outside grinding surface of the workpiece is individually ground, and by the automatic switching by the control means, the spindle center and the tailstock center are used as the live center, and the grinding wheel is used to set the outside diameter surface of the workpiece. After heavy grinding, the outer diameter surface of the workpiece is finish-grinded by the grinding wheel using the spindle center and the tailstock center as a dead center, so that the above-described effects are effectively exhibited and a series of cylindrical grinding processes It is possible to automatically switch between the live center and dead center within the cycle, and the cycle time is short and efficient with high accuracy. It is possible to execute the cylinder grinding.

  Further, prior to the heavy grinding, the spindle center and the tailstock center are used as a live center, and both the centers are ground in the machine by the grinding wheel so as to prevent the live shake of these centers. Even if the center of the center or the center of the tailstock is eccentric with respect to the center of rotation, the center of rotation of the work supported by these live centers will be parallel to the axis of the grinding wheel. The eccentricity of the shaft center does not affect the cylindrical grinding of the workpiece by the grinding wheel, and the same precision as the finishing grinding by the dead center method while taking advantage of the heavy grinding with the specified accuracy and the advantages of heavy grinding. Can also be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1
A cylindrical grinder according to the present invention is shown in FIGS. 1 to 6, and this cylindrical grinder grinds the outer diameter surface Wa of the workpiece W while supporting the axial center positions of both ends of the cylindrical workpiece W in the center. Specifically, the headstock 1 and the tailstock 2 constituting the center support portion of the workpiece W, the grindstone base 3 constituting the grinding portion of the workpiece W, the center support portions 1 and 2 and the grinding processing. The control part (control means) 4 which controls the part 3 in conjunction is provided as a main part.

  Specifically, as shown in FIGS. 1A and 1B, a table 6 is provided at the front portion on the apparatus bed 5 so as to be movable in the left-right X direction (traverse direction). The center support portions (spindle head and tailstock) 1 and 2 are installed, and the grinding portion (grinding stone stand) 3 is placed in the front-rear direction Y, that is, the traverse direction X of the table 6 at the rear position of the table 6. On the other hand, it is configured to be movable in the direction of the vertical cut. Although not specifically shown, the table is reciprocated in the traverse direction X by a traverse device (not shown), and the grindstone table 3 is reciprocated in the cutting direction X of the grinding wheel by a notch not shown. The The drive source of the traverse device and the cutting device is electrically connected to the control unit 4.

  The center support parts 1 and 2 have both functions as a live center method suitable for heavy grinding and a dead center method suitable for finish grinding. It is set as the structure which can be demonstrated.

  The headstock 1 supports one end of the workpiece W as a center and gives a rotational force to the workpiece W. Specifically, as shown in FIG. 2, the spindle center that supports the axial center position of one end of the workpiece W. 10 and a work rotating part (work rotating means) 11 for rotationally driving the work W.

  The spindle center 10 is provided with a tapered end portion 10a that is inserted into and engaged with a center hole Wb provided at the axial center of one end of the workpiece W. Although not specifically shown, the spindle center 10 rotates to the spindle stock 1. The main shaft 12 is detachably mounted and fixed to the tip end of the main shaft 12 that is supported so that the main shaft 12 can be removed and replaced. Drive coupled. The drive motor 14 is a servo motor, and is electrically connected to the control unit 4.

  Specifically, the workpiece rotating unit 11 is composed of a scraping drive device that rotationally drives the workpiece W via a scraper 11a attached to an end of the workpiece W on the headstock 1 side. In this rake drive device 11, a rotary drive unit 15 is supported on the outer periphery of the tip end portion of the main shaft 12 so as to be concentric and rotatable with the main shaft 12, and via a power transmission mechanism 16 such as a power transmission belt or a gear mechanism. The driving motor 17 is a work rotation driving source. The drive motor 17 is a servo motor, and is electrically connected to the control unit 4. In addition, the rotational drive unit 15 is integrally provided with a keratin driving bar 11b extending horizontally to the front, and the knitting driving bar 11b is attached to and fixed to the sever 11a detachably attached to the workpiece W. It is set as the structure engaged in a rotation direction.

  The tailstock 2 supports the other end of the work W as a center. Specifically, as shown in FIG. 2, the tailstock 2 includes a tailstock center 20 that supports the axial position of the other end of the work W, A center pressing adjusting portion (center pressing adjusting means) 21 for adjusting the axial pressing force (tail pressing load) in the axial direction of the pedestal 2 is provided.

  The tailstock center 20 is provided with a tapered end portion 20a that is inserted into and engaged with a center hole Wc provided at the axial center position of the other end of the work W, and is rotatably supported by the tailstock 2. It is attached and fixed to the tip 22a of the tailstock shaft 22 so that it can be removed and replaced. The tailstock 22 is rotatably supported by the tailstock 2 and is drivingly connected to a drive motor 24 that is a tailstock spindle rotation drive source via a power transmission mechanism 23 such as a power transmission belt or a gear mechanism. ing. The drive motor 24 is a servo motor, and is electrically connected to the control unit 4.

  Specifically, the tail pressing adjustment unit 21 is configured to switch and adjust the axial centering load of the tailstock center 20 in the tailstock 2 between heavy grinding and finish grinding. 1 comprises a center pressing adjustment spring 25 that presses and moves the tailstock shaft 22 forward in the axial direction, and a hydraulic cylinder 26 that reciprocates the tailstock shaft 22 in the axial direction.

  A specific internal structure of the tailstock 2 of the illustrated embodiment is shown in FIG. 3, and will be described in detail below including the specific structure of the tailstock adjusting unit 21.

  The tailstock 2 includes the above-described components 21 (25, 26), 22, and 24 in a tailstock housing 30 fixed on the table 6.

  The tailstock 22 is supported by the tailstock housing 30 through the front and rear radial bearing portions 31a and 31b of the hydrostatic bearing 31 so as to be rotatable and movable in the axial direction. The tailstock center 20 is coaxially and detachably attached to the tapered shank hole 22b of the distal end portion 22a through the tapered shank 20b of the proximal end portion (taper fitting mounting structure). . Although not specifically shown, the attachment structure of the spindle center 10 to the rotation spindle 12 is also a taper fitting attachment structure similar to the tailstock 22.

  A tailstock shaft rotation drive unit 32 is drive-coupled to the rear end portion of the tailstock shaft 22 by a key fitting 33 so as to be relatively movable in the axial direction and integrally rotatable in the rotational direction. At the same time, the tailstock shaft rotation drive unit 32 is in the form of a power transmission pulley, and the output shaft of the drive motor 24 fixed to the tailstock housing 30 via the power transmission belt 34a and the power transmission pulley 34b. Drive-connected to 24a. The tailstock rotation drive unit 32 is rotatably supported on the outer periphery of the rear end of a cylinder body 40 of a hydraulic cylinder 26 of the center pressure adjusting unit 21 described later via radial bearings 43 and 43.

  The center pressure adjusting spring 25 constituting the center pressure adjusting portion 21 is formed of a compression spring, and is interposed at the rear end portion of the tailstock shaft 22 so that the tailstock shaft 22 is axially forward with respect to the tailstock housing 30. It is made the structure which presses to. As will be described later, the center pressing adjustment spring 25 mainly functions as a means for adjusting a tail pressing load during finish grinding.

  Specifically, a cylindrical concave portion 35 extending along the axial center is provided at the rear end portion of the tailstock shaft 22 so as to be open rearwardly, and in the cylindrical concave portion 35, the center pressing adjusting spring 25 is provided with a spring receiving shaft. The interior is held through 36. The center pressing adjustment spring 25 has a tip end portion 25 a abuttingly engaged with a tip receiving seat 37 of the spring receiving shaft 36, and a rear end portion 25 b provided in the tailstock housing 30. Is in contact with and engaged. The spring receiving shaft 36 is connected to the bottom of the cylindrical recess 35 of the tailstock shaft 22 via a radial bearing 39 so as to be relatively rotatable and integrally connected in the axial direction. An end portion 36b is inserted and supported so as to be slidable inside a cylindrical adjustment handle 38a of the adjustment portion 38. The spring pressure adjusting portion 38 is supported by being screwed and supported by a nut member 38b attached and fixed to the tailstock housing 30 with the adjusting handle 38a.

  As a result, the center pressing adjustment spring 25 constantly urges and biases the tail pressing shaft 22 with a predetermined pressure forward in the axial direction, and rotates the adjustment handle 38a of the spring pressure adjusting unit 38 to rotate the spring. The urging force (center pressing force) can be adjusted as appropriate.

  The hydraulic cylinder 26 is provided on the outer peripheral portion of the tailstock shaft 22 and has a structure for reciprocating the tailstock shaft 22 relative to the tailstock housing 30 in the axial direction. That is, the hydraulic cylinder 26 moves forward and backward of the tailstock center 20 when the workpiece W is attached to and detached from the center support portions 1 and 2, and the tailstock load when the workpiece W is center-supported by the center support portions 1 and 2. Combines both functions of the adjustment operation. As will be described later, the hydraulic cylinder 26 functions as a means for adjusting the tailstock load during heavy grinding.

  Specifically, the cylinder body 40 of the hydraulic cylinder 26 is configured by disposing the tailstock shaft 22 to be actuated at the axial center position. That is, a cylindrical cylinder main body 40 is integrally provided in the tailstock housing 30, and an operating piston 41 is provided in the cylinder main body 40 so as to be able to reciprocate in the front-rear direction. In addition, the tailstock 22 is connected to the hydrostatic bearing 31 so as to be relatively rotatable and integrally driven in the axial direction.

  In other words, the working piston 41 has a cylindrical shape that moves in the front-rear direction in a cylindrical space formed between the cylinder body 40 and the tailstock 22, and the center portion in the front-rear direction has a hydrostatic bearing. Through the 31 thrust bearing portions 31c and 31c, the annular engaging flange 22c of the tailstock shaft 22 is relatively rotatable and integrally engaged in the axial direction. For this purpose, a bearing flange 42 is integrally coupled to the inner diameter portion of the working piston 41, and the bearing surfaces 42a and 42b of the bearing flange 42 are opposed to the front and rear surfaces of the engagement flange 22c of the tailstock shaft 22, The thrust bearing portions 31c and 31c are formed between these opposing surfaces, respectively.

  Front and rear cylinder chambers 40a and 40b are formed at the front and rear positions of the operating piston 41 in the cylinder body 40, and pressure oil from the cylinder hydraulic pressure supply device 46 is selectively and alternately introduced into the front and rear cylinder chambers 40a and 40b. By being supplied, the working piston 41 and the tailstock 22 reciprocate in the front-rear direction.

  In this connection, a dog 44 is attached to the rear end of the tailstock 22 and front and rear proximity switches 45 a and 45 b for detecting the dog 44 are provided as limit switches in the vicinity of the dog 44. . Both the front and rear proximity switches 45a and 45b are electrically connected to the control unit 4, and thereby the forward end position and the backward movement in the back and forth movement of the tailstock shaft 22, that is, the tailstock center 2, by the hydraulic cylinder 26. The end position is regulated.

  Although not specifically shown, the cylinder hydraulic pressure supply device 46 has a conventionally known basic structure, and a hydraulic pump of a hydraulic source and a pressure oil control valve of a hydraulic circuit are electrically connected to the control unit 4. ing.

  The hydraulic cylinder 26 is operated when the control unit 4 attaches / detaches the workpiece W to / from the spindle center 10 and the tailstock center 20 to move the tailstock center 20 forward and backward, and the spindle center 10 and the center. The push center 20 operates when it functions as a live center that supports the workpiece W while being rotationally driven in synchronization with each other, and urges the tailstock center 20 forward with a predetermined pressure in the axial direction. When the spindle center 10 and the tailstock center 20 function as a dead center for supporting the workpiece W in a state where the rotation is stopped, the spindle center 10 and the tailstock center 20 are stopped.

  Further, as described above, the hydrostatic bearing 31 is a hydraulic hydrostatic bearing including the front and rear radial bearing portions 31a and 31b and the thrust bearing portions 31c and 31c, and the front and rear radial bearing portions 31a and 31b are the cores. The push shaft 22 is rotatably supported on the tailstock housing 30, and the thrust bearing portions 31c and 31c are configured to rotate the tailstock shaft 22 with respect to the operating piston 41 of the hydraulic cylinder 26 and integrally in the axial direction. To support.

  The bearing hydraulic pressure supply device 47 of the hydrostatic bearing 31 has a conventionally known basic structure (not shown), and a hydraulic pump of the hydraulic source and a pressure oil control valve of the hydraulic circuit are provided in the control unit 4. Electrically connected.

  In the center support portions 1 and 2 configured as described above, as described above, the spindle center 10 and the tailstock center 20 are configured to selectively function as a live center or a dead center.

  Next, functional configurations of the live center and the dead center will be described with reference to FIG.

(A) Live center method:
In the live center system, as shown in FIG. 4A, the spindle center 10 and the tailstock center 20 function as a live center, and the spindle center 10 and the tailstock center 20 are rotationally driven in synchronization with each other. While supporting the workpiece W in the center.

  That is, in the live center system, the drive motor 14 that is the main shaft rotation drive source and the drive motor 24 that is the tailstock rotation drive source are synchronized with each other and with respect to the drive motor 17 that is the workpiece rotation drive source. Thus, the spindle center 10 and the tailstock center 20 support the workpiece W while being rotationally driven.

  Further, when the spindle center 10 and the tailstock center 20 rotate in synchronization with the workpiece W supported by the center, there is no relative rotation with the workpiece W, and no heat generation or wear occurs between the workpiece W and the workpiece W. For this reason, a large tail pushing load can be taken. Therefore, the hydraulic cylinder 26 of the center pressing adjusting portion 21 is hydraulically driven, and the tail center 20 is moved forward, whereby the center supporting center of the workpiece W is supported. The pressing load is set to a predetermined large value.

  Strictly speaking, the tailstock load in this case is the cooperative action of the center pressing adjustment spring 25 that always elastically biases the tailstock center 20 forward (the elastic biasing action of the center pressing adjustment spring 25). In cooperation, the hydraulic cylinder 26 is set by additional biasing of the tailstock center 20 forward with a predetermined pressure in the axial direction, but is substantially set by drive control of the hydraulic cylinder 26.

  In the live center type center support portions 1 and 2, the spindle center 10 and the tailstock center 20 rotate. Therefore, the rotational vibration caused by the assembling accuracy of the centers 10 and 20 may cause the workpiece runout. However, there is no heat generation or wear between the workpiece W and high support stiffness of the workpiece W can be secured by a large tailstock load. Is suitable for heavy grinding (for example, rough grinding) having a large grinding load and a large grinding load (see the upper part of Table 1).

(B) Dead center method:
In the dead center method, as shown in FIG. 4 (b), the spindle center 10 and the tailstock center 20 function as a dead center, and the spindle center 10 and the tailstock center 20 hold the workpiece W in a state where the rotation is stopped. Support the center.

  That is, in the dead center system, the drive motor 14 that is the main shaft rotational drive source and the drive motor 24 that is the tailstock rotational drive source are stopped, and only the drive motor 17 that is the rotational drive source is rotationally driven. The center 10 and the tailstock center 20 support the workpiece W in the center while the rotation is stopped.

  Further, if the workpiece W is center-supported in a state where the spindle center 10 and the tailstock center 20 are stopped, relative rotation with the rotating workpiece W occurs, and heat and wear are generated between the workpiece W and the workpiece W. . For this reason, it is not possible to make a large load on the tail, and therefore, the hydraulic cylinder 26 of the center pressing adjustment unit 21 stops driving, and the center pressing adjustment spring 25 constantly urges the tail pressing center 20 forward. Only the tailstock load acts, whereby the center support tailload of the workpiece W is set to a predetermined small value.

  In the center support portions 1 and 2 of the dead center system, since the spindle center 10 and the tailstock center 20 are stopped from rotating, heat is generated and worn between the workpiece W and a small tailstock. Although the support rigidity of the workpiece W is low due to the load, on the other hand, there is no rotational vibration caused by the assembly accuracy of the centers 10 and 20, and no high-speed grinding accuracy is induced in the workpiece W supporting the center. It is suitable for finish grinding that requires high grinding accuracy with a small cutting depth and a small grinding load (see the lower part of Table 1).

  In the cylindrical grinding machine of the present embodiment, the spindle center 10 and the tailstock center 20 are configured to selectively function as a live center or a dead center, so that the processing from the live center method to the dead center is performed. When the system is converted to machining by the system, the spindle center 10 and the tailstock center 20 are respectively driven and controlled so as to stop at a fixed position in the rotational direction of the rotating spindle 12 and the tailstock 22 (shaft rotation fixed position stop). It is supposed to be configured.

  That is, the spindle center 10 and the rotation spindle 12 in the spindle stock 1 and / or the tailstock center 20 and the tailstock shaft 22 in the tailstock 2 are arranged so that their axial centers substantially coincide with each other. It is extremely difficult to build in and is usually slightly eccentric.

For example, as shown in FIG. 5 (a), the headstock 1, when the tip of the axis X _10, i.e. the main axis center 10 of the spindle center 10 is eccentric with respect to the axis X ₁₂ of the rotary spindle 12, and / or Consider a case in the tailstock 2 where the shaft center X _{20 of the} tailstock center 20, that is, the tip of the tailstock center 20 is eccentric with respect to the shaft center X _{22 of the} tailstock shaft ₂₂ .

In the live center spindle center 10 and the tailstock center 20 is rotated, as shown in FIG. 6 (a), the rotation center X _W also the grinding wheel of a workpiece W which is rotatably supported by the both centers 10, 20 There the inclined state with respect to the axis X ₅₀ of 50, both rotational shake of the center 10, 20 as the workpiece W runout (X _W), and the inability to expect a high grinding accuracy is as described above.

If the spindle center 10 and the tailstock center 20 are configured to selectively function as a live center or a dead center as in the present embodiment, the system conversion from live center processing to dead center processing is performed. When the two centers 10 and 20 are stopped at arbitrary positions in the rotation direction of the rotation main shaft 12 and the tailstock shaft 22 when, for example, shown in (i) and (ii) of FIG. as such, the main axis center 10 and the rotary spindle 12, and / or eccentricity of the tailstock center 20 and tailstock shaft 22 induces an inclined state with respect to the axis X ₅₀ of the grinding wheel 50 of the rotation center X _W of the workpiece W and will have, moreover, the inclined state with respect to the axis X ₅₀ of the grinding wheel 50 of the rotation center X _W of the workpiece W is also not fixed posture disjointed, high grinding accuracy is an advantage of the dead center type is obtained There.

  In view of this point, in the present embodiment, the spindle center 10 and the rotating spindle 12 and / or the tailstock center 20 and the tailstock are changed when the live center method is changed to the dead center method. As shown in FIG. 5C, the spindle center 10 and the tailstock center 20 are stopped at fixed positions in the rotational direction of the rotary spindle 12 and the tailstock 22 so that the eccentricity of the shaft 22 does not affect the grinding accuracy. It is configured to be driven and controlled so as to (stop shaft rotation fixed position).

Specifically, in a state converted to a dead center system in which the spindle center 10 and the tailstock center 20 are fixed, a straight line connecting the centers 10 and 20 is a grinding wheel 50 as shown in FIG. be parallel with the axis X ₅₀ of a result, the rotation center X _W of the workpiece W also becomes parallel to the axis X ₅₀ of the grinding wheel 50, the axis of the eccentric main shaft center 10 and / or the tailstock center 20 A predetermined grinding accuracy can be ensured without affecting the cylindrical grinding of the workpiece W by the grinding wheel 50.

  In the illustrated embodiment, the selective switching between the live center and the dead center by the center pressing adjustment unit 21 is basically performed by automatic switching by the control unit 4 as will be described later. This is also done by manually operating the switch.

  The grinding wheel base 3 includes a grinding wheel 50 that grinds the cylindrical outer diameter surface Wa of the workpiece W supported by the center support portions 1 and 2. As shown in FIG. 1, the grinding wheel 50 has an outer peripheral surface 50a that is a cylindrical grinding wheel surface, and has a generally known general basic structure (not shown). In other words, the grinding wheel 50 is detachably mounted and fixed to the grinding wheel shaft 51. The grinding wheel shaft 51 is rotatably supported by the grinding wheel chassis 3 and rotated by a drive motor or the like via a power transmission belt or a gear mechanism. Drive coupled to the drive source. The rotational drive source of the grinding wheel 50 is a servo motor, and is electrically connected to the control unit 4.

  The control unit 4 controls each drive source in the headstock 1, the tailstock 2 and the grindstone table 3 in conjunction with each other, and specifically includes a CPU, a ROM, a RAM, an I / O port, and the like. It is a CNC device composed of a microcomputer.

  As described above, the control device 6 includes drive sources (drive motors 14, 17, 24, etc., and drive sources of the hydraulic pressure supply devices 46, 47) in the headstock 1, the tailstock 2, and the grindstone table 3. Various sensors such as the proximity switches 45a and 45b are electrically connected, and a control program for executing a cylindrical grinding process (cylindrical grinding method) described below is preliminarily or numerically controlled as an operation panel (not shown). Input is appropriately and set by a keyboard or the like.

  Thus, in the cylindrical grinding machine configured as described above, the workpiece W is rotated at a high speed while being rotated at a low speed by the workpiece rotating portion 11 while being supported by the center support portions 1 and 2 at the center. 50, the outer diameter surface Wa is subjected to cylindrical grinding such as traverse grinding or plunge cut grinding. As described above, the live center method (method in which the spindle center 10 and the tailstock center 20 function as a live center) is used. Rough grinding (heavy grinding) of the outer diameter surface Wa of the workpiece W and finish grinding of the outer diameter surface Wa of the workpiece W by a dead center method (method in which the spindle center 10 and the tailstock center 20 function as a dead center). Are performed independently, and the workpiece W is removed from the center support parts 1 and 2 by automatic switching by the control part 4 described above. While the center support without, grinding of the two kinds of processing conditions are different, such as requests grinding accuracy of rough grinding and finish grinding on the workpiece W is continuously performed.

  That is, (1) In the rough grinding process, the drive motor 17 that is a work rotation drive source is driven to rotate, and the drive motor 14 that is a spindle rotation drive source and the drive motor 24 that is a tailstock rotation drive source are The main shaft center 10 and the tailstock center 20 of the center support portions 1 and 2 are synchronized with the drive motor 17 so that they are synchronized with each other and are rotated at a low speed by the rotation drive portion 15. The grinding wheel 50 that rotates at high speed and rotates at high speed while supporting the workpiece W as a live center (supporting load → large, support stiffness of the workpiece W → large), and heavy grinding the outer diameter surface Wa of the workpiece W Processing (cutting amount → large, grinding load → large) is performed.

  (2) When the rough grinding process is completed, the spindle center 10 of the center support portions 1 and 2 is controlled by the control portion 4 in a state where the workpiece W is supported as it is without being removed from the center support portions 1 and 2. In addition, the support system of the tailstock center 20 is automatically switched from the live center to the dead center.

(3) In the finish grinding process, the drive motor 17 that is the work rotation drive source is driven to rotate, and the drive motor 14 that is the spindle rotation drive source and the drive motor 24 that is the tailstock rotation drive source are stopped. Thus, the spindle center 10 and the tailstock center 20 of the center support portions 1 and 2 support the work W as a dead center in a state where the rotation is stopped (the tailstock load → small, the support rigidity of the work W → small). The grinding wheel 50 that rotates at high speed performs finish grinding (cutting amount → small, grinding load → small) on the outer diameter surface Wa of the workpiece W.

  FIG. 6 shows operation timings of the work rotation drive source (drive motor) 17, the main shaft rotation drive source (drive motor) 14, and the tailstock shaft rotation drive source (drive motor) 24 in the above cylindrical grinding process.

  As described above, according to the cylindrical grinding machine of the present embodiment, the headstock 1 including the spindle center 10 that supports the center position of one end of the workpiece W and the center position of the other end of the workpiece W as the center. A tailstock 2 having a tailstock center 20 to be supported, and a grinding wheel base 3 having a grinding wheel 50 for grinding the cylindrical outer diameter surface Wa of the workpiece W supported by the spindle stock 1 and the tailstock 2 are provided. In the headstock 1, the spindle center 10 is rotatably supported and is connected to a drive motor 14 which is a spindle rotation drive source, and a work rotating unit 11 for rotating the work W is provided. In the tailstock 2, the tailstock center 20 is rotatably supported and connected to a drive motor 24 which is a tailstock shaft rotation drive source, and the tailstock pressure in the axial direction of the tailstock 2 is also shown. (Tailstock The spindle center 10 and the tailstock center 20 are automatically and selectively driven as a live center that supports the workpiece W while being rotationally driven in synchronization with each other. Or, since it is configured to function as a dead center that supports the workpiece W in a state where the rotation is stopped, the following effects can be obtained, and it is versatile and greatly increases the cycle time with high accuracy. Shortened cylindrical grinding can be realized.

(I) Since the spindle center 10 of the headstock 1 and the tailstock center 20 of the tailstock 2 can be selectively switched as a live center or a dead center, heavy grinding processing ( For example, grinding processing with different processing conditions such as required grinding accuracy such as rough grinding) and finish grinding can be executed.

  That is, in the live center system in which the spindle center 10 and the tailstock 20 of the tailstock 2 function as a live center, the spindle center 10 and the tailstock center 20 rotate to generate heat between the workpiece W supported by the center.・ There is no wear, and this makes it possible to perform heavy grinding with a large cutting depth and a large grinding load with high rigidity and high load support, while the spindle center 10 and the tailstock 2 have tailstocks. In the dead center system in which the center 20 functions as a dead center, the spindle center 10 and the tailstock center 20 do not rotate, so there is no runout during center rotation due to the assembly accuracy of these centers. In addition, it is possible to perform finish grinding in which high-precision grinding accuracy is required because the workpiece W that supports the center hardly causes runout.

(Ii) Since the spindle center 10 of the headstock 1 and the tailstock 20 of the tailstock 2 can be selectively switched as a live center or a dead center by a simple switching operation, Center reassigning work that requires labor is not required at all, and heavy grinding and finish grinding can be efficiently switched and executed.

  That is, a spindle 4, a tailstock 2, and a control unit 4 that controls the drive sources in the spindle stock 1 in conjunction with each other are provided. By this automatic switching by the control unit 4, the spindle center 10 and the tailstock 20 are live. By controlling to function as a center and a dead center, it is possible to automatically switch between a live center and a dead center within a series of cylindrical grinding cycles, and perform high-precision cylindrical grinding that greatly reduces cycle time. It becomes possible to do.

(Iii) Since the spindle center 10 and the tailstock center 20 can be switched from the live center to the dead center while maintaining the center support state of the work W, the center shift of the work W due to the change of the center support method occurs. In this respect, high grinding accuracy can be obtained.

(Iv) Since both the spindle center 10 and the tailstock center 20 as a live center are driven to rotate positively and synchronously by a rotation driving source, relative rotation between the spindle W and the workpiece W supported by the center is possible. The possibility of occurrence is extremely low, and the generation of heat and wear at the center support portion can be effectively and reliably avoided.

(V) Since the center pressing adjusting portion 21 for adjusting the axial pressing force (the tail pressing load) in the axial direction of the tailstock 2 is provided, the tail pressing load on the work W as the live center or the dead center is optimized respectively. As a result, there is a problem that the tailstock load becomes large and high at the time of dead center and develops heat generation and wear of the center support part. Occurrence of the problem that the support rigidity between the center and the workpiece W becomes insufficient due to a small and light load is effectively prevented.

Embodiment 2
This embodiment is shown in FIG. 7, and is configured to perform in-machine center grinding in the cylindrical grinding machine of the first embodiment.

For example, as shown in FIG. 8 (a), the headstock 1, when the tip of the axis X _10, i.e. the main axis center 10 of the spindle center 10 is eccentric with respect to the axis X ₁₂ of the rotary spindle 12, and / or Consider a case in the tailstock 2 where the shaft center X _{20 of the} tailstock center 20, that is, the tip of the tailstock center 20 is eccentric with respect to the shaft center X _{22 of the} tailstock shaft ₂₂ .

If the spindle center 10 and the tailstock 20 are fixed dead centers, the spindle stock 1 and / or the tailstock 2 are moved by a minute distance, and as shown in FIG. by collimating the straight line connecting 20 and the axis X ₅₀ of the grinding wheel 50, the rotation center X _W of the workpiece W will be parallel to the axis X ₅₀ of the grinding wheel 50, the spindle center 10 described above and The eccentricity of the shaft center of the tailstock center 20 does not affect the cylindrical grinding of the workpiece W by the grinding wheel 50, and grinding with a predetermined accuracy is possible.

On the other hand, if the spindle center 10 and the tailstock center 20 are rotationally driven, the eccentricity correction as in the case of the above-described dead center cannot be performed, as shown in FIG. As described above, the straight line X connecting the centers 10 and 20 is inclined with respect to the axis X ₅₀ of the grinding wheel 50, that is, the rotation center X of the workpiece W supported by the centers 10 and 20 for rotation. _W is also in an inclined state with respect to the axis X ₅₀ of the grinding wheel 50.

Then, in the cylindrical grinding of a live center type in a state where the straight line connecting this manner both centers 10, 20 is inclined with respect to the axis X ₅₀ of the grinding wheel 50, rotational camera shake of both centers 10, 20 as it is The workpiece W becomes runout (X _W ), and grinding with the desired accuracy cannot be performed.

  In the present embodiment, in order to eliminate such problems in cylindrical grinding by the live center method, the spindle center 10 and the tailstock center 20 are prior to heavy grinding of the outer diameter surface Wa of the workpiece W by the live center method. Is used as a live center, and both the centers 10 and 20 are ground in an in-machine with a grinding wheel 60 for grinding an in-machine center (both end portions are tapered grinding wheel surfaces 60a and 60b). To prevent live shake.

That is, for example, as shown in FIG. 7A, the shaft centers X ₁₀ and X ₂₀ of the main spindle center 10 and the tailstock center 20 are respectively relative to the shaft centers X ₁₂ and X _{22 of the} rotary main shaft 12 and the tailstock shaft ₂₂ . In the case of eccentricity, first, the grinding wheel 60 for in-machine center grinding is attached to the grinding wheel shaft 51 of the grinding wheel base 1, and the taper of the rotating grinding wheel 60 is rotated while the tailstock center 20 is rotationally driven by the drive motor 24. The shape grinding wheel surface 60b grinds the tip portion of the tailstock center 20 (see FIG. 7A), and then the taper shape of the grinding wheel 60 that rotates while driving the spindle center 10 by the drive motor 14 is rotated. The grindstone surface 60b grinds the tip of the tailstock center 20 (not shown).

This machine center grinding, the tip portion 10a of the both centers 10, 20, 20a, as shown in FIG. 7 (b), tapered to match the axis X _12, X ₂₂ of the rotary spindle 12 and the tailstock 22 The taper shape is corrected.

Thus, in the heavy grinding process in the cylindrical grinder subjected to in-machine center grinding as described above, the workpiece W is rotated and supported by the spindle center 10 and the tailstock center 20 which are live centers (the tailstock load → Large, support rigidity of the workpiece W → large), and the outer diameter surface Wa is ground by the grinding wheel 50 that rotates at high speed (cutting amount → large, grinding load → large), as shown in FIG. Even if the shaft centers X ₁₀ and X _{20 of the} main spindle center 10 and the tailstock center 20 are eccentric with respect to the shaft centers X ₁₂ and X _{22 of the} rotary main shaft 12 and the tailstock shaft ₂₂ , these live centers 10. , 20 of the tip portion 10a, the rotation center X _W of the workpiece W supported by the 20a becomes to be parallel to the axis X ₅₀ of the grinding wheel 50, without causing the rotation shake of the workpiece W, as a result, the center 10, 20 axis The eccentricity of X ₁₀ and X ₂₀ does not affect the cylindrical grinding of the workpiece W by the grinding wheel 50, not to mention heavy grinding with a predetermined accuracy, and further, while taking advantage of the heavy grinding, the dead center It is also possible to obtain the same accuracy as finish grinding by the method.

Further, in the cylindrical grinder of the present embodiment, as described above, by performing in-machine center grinding, the tip portions 10a and 20a of the spindle center 10 and the tailstock center 20 are as shown in FIG. As a result of the correction to the tapered shape corresponding to the axial centers X ₁₂ and X ₂₂ of the rotating main shaft 12 and the tailstock shaft ₂₂ , in the first embodiment, the system is converted from the live center system to the dead center system. The drive control that has been performed at the time of the rotation, that is, the axial rotation fixed position stop of the main spindle center 10 and the tailstock center 20 (stopping at the fixed position in the rotation direction of the rotary main spindle 12 and the tailstock 22) becomes unnecessary. .
Other configurations and operations are the same as those of the first embodiment.

Embodiment 3
This embodiment is shown in FIG. 9, and the mounting structure of the spindle center 10 and the tailstock center 20 is modified in the cylindrical grinding machine of the first embodiment.

  That is, the mounting structure of the spindle center 10 and the tailstock center 20 is the taper fitting mounting structure as shown in FIG. 3 in the first and second embodiments as described above. As shown in FIG. 9, either one of the taper fitting mounting structure A and the end surface mounting structure B can be selectively employed.

  In the taper fitting mounting structure, as shown in FIG. 9A, the base mounting portion 10b (20b) of the spindle center 10 (tailstock center 20) is formed in a tapered shank shape as shown in the figure, and this is supported. Then, a taper shank hole 12b (22b) is opened at the center of the tip 12a (22a) of the rotating main shaft 12 (the tailstock shaft 22), and these 10b (20b) and 12b (22b) are detachably fitted. It is configured to be fixed together.

On the other hand, as shown in FIG. 9 (b), the end face mounting structure is such that the base portion of the spindle center 10 (the tailstock center 20) is integrally formed with the flat mounting flange portion 10c (20c). Te, and the distal end surface 12c of the rotary spindle 12 (the tailstock 22) (22c) is formed in the axis X ₁₂ flat mounting end surface orthogonal to (X ₂₂₎ of the rotary spindle 12 (the tailstock 22), the A configuration in which the mounting flange portion 10c (20c) is detachably tightened and fixed by mounting bolts 70, 70,... In a state where the mounting flange portion 10c (20c) is in contact with and engaged with the front end surface 12c (22c) of the rotary main shaft 12 (tailstock shaft 22). It is said that.

Therefore, in the mounting structure of the spindle center 10 and the tailstock center 20 configured as described above, both the taper fitting mounting structure A and the end surface mounting structure B as shown in Table 2 are taken into consideration. Either one of the attachment structures A and B can be selectively employed as appropriate according to the purpose.
Other configurations and operations are the same as those of the first embodiment.

  The above-described embodiment is merely a preferred embodiment of the present invention, and the present invention is not limited thereto, and various design changes can be made within the scope.

The external appearance structure of the cylindrical grinding machine which is Embodiment 1 of this invention is shown, Fig.1 (a) is a front view, FIG.2 (b) is a top view. It is a schematic block diagram which shows the main structures of the cylindrical grinding machine. It is front sectional drawing which shows the specific internal structure of the tailstock of the cylindrical grinding machine. FIG. 4A shows an operation configuration of a live center system, and FIG. 4B shows an operation configuration of a dead center system. FIG. 5A is a view for explaining a work support state when the spindle center and / or the centering center is eccentric in the cylindrical grinding machine when the live center method is changed to the dead center method. ) Is a front view showing an example of the support state of the workpiece by the live center method, and FIG. 5B is a view of the rotation direction of the rotating spindle and the tailstock when the method is converted to the dead center method while the workpiece is supported. FIG. 5C is a front view showing two examples of the support state of the workpiece when both centers are stopped at an arbitrary position, and FIG. 5C shows the rotation when the system is converted to the dead center method while the workpiece is still supported. It is a front view which shows an example of the support state of the workpiece | work when both centers are stopped in the fixed position of the rotation direction of a main shaft and a tailstock shaft. It is a thousand figure which shows the operation timing of the drive motor for the spindle rotation work motor, the spindle rotation drive motor, and the tailstock spindle rotation drive motor in the cylindrical grinding process by the cylindrical grinder. FIG. 7A is a diagram for explaining in-machine center grinding in the cylindrical grinder according to the second embodiment of the present invention, and FIG. 7A shows a case where the spindle center and the tailstock center are eccentric with respect to the spindle and the tailstock. FIG. 7B is a front view showing a state where the center of the tailstock is ground in the machine, FIG. 7B is a front view showing a state where the eccentricity of the spindle center and the center of the center is corrected by the center grinding in the machine, and FIG. It is a front view which shows the state which carries out the cylindrical grinding of the workpiece | work by the live center system using the spindle center and the centering center which were eccentrically corrected. FIG. 8A is a view for explaining a case where the main spindle center and the tailstock center are eccentric in the cylindrical grinder, and FIG. 8A shows the support of the workpiece when the main spindle center and the tailstock center are eccentric with respect to the main spindle and the tailstock shaft. FIG. 8B is a front view showing a state in which the support state of the workpiece is corrected by the dead center method, and FIG. 8C is a rotation by the live center method while the workpiece is supported. It is a front view which shows the state to support. FIG. 9A is a view showing a mounting structure of a spindle center and a tailstock center in a cylindrical grinding machine according to a third embodiment of the present invention. FIG. 9A is a front view showing a partially cut-away taper fitting structure, and FIG. ) Is a front view showing a part of the end face mounting structure.

Explanation of symbols

W Work Wa Work outer diameter surface A Taper fitting mounting structure B End surface mounting structure 1 Headstock 2 Tailstock 3 Grinding wheel base 4 Control unit (control means)
5 Equipment Bed 6 Table 10 Spindle Center 10a Spindle Center Tip 10b Spindle Center Taper Shank 10c Spindle Center Mounting Flange 11 Work Rotating Unit (Work Rotating Means)
12 Rotating spindle 12b Tapered shank hole 12c of rotating spindle 12c End face 13 of rotating spindle 13 Drive motor (spindle rotation drive source)
15 Rotation Drive Unit 16 Drive Motor (Work Rotation Drive Source)
20 Tail Center 20a Tip Center 20b Tail Center Taper Shank 20c Tail Center Mounting Flange 21 Center Press Adjustment Unit (Center Press Adjustment Unit)
22 Tailstock shaft 22b Taper shank hole 22c of tailstock shaft Mounting end surface 24 of tailstock shaft Drive motor (Tailstock shaft rotation drive source)
25 Center pressure adjusting spring 26 Hydraulic cylinder 31 Hydrostatic bearing 46 Cylinder hydraulic supply device 47 Bearing hydraulic supply device 50 Grinding wheel 60 Grinding wheels 60a, 60b for in-machine center grinding Taper-shaped grinding wheel surface

Claims (14)

A cylindrical grinding machine that supports the axial positions of both ends of the workpiece and grinds the outer diameter surface of the workpiece,
A headstock with a spindle center that supports the axial position of one end of the workpiece;
A tailstock with a tailstock center that supports the axial position of the other end of the workpiece;
A grinding wheel head equipped with a grinding wheel for grinding a cylindrical outer diameter surface of a workpiece supported by the spindle stock and the tailstock.
In the headstock, the spindle center is rotatably supported and connected to a spindle rotation drive source, and is provided with a work rotation means for driving the workpiece to rotate.
In the tailstock, the tailstock center is rotatably supported and is drivingly connected to a tailstock shaft rotation drive source, and a tail pressure adjusting means for adjusting a tailstock pressure in the axial direction of the tailstock is provided. And
The spindle center and the tailstock center selectively function as a live center that supports the workpiece while being rotationally driven in synchronization with each other, or as a dead center that supports the workpiece while the rotation is stopped. A cylindrical grinding machine characterized by Control means for controlling the spindle head, the tailstock and the driving source in the spindle stock in conjunction with each other,
The control means functions as the live center for supporting the workpiece while the spindle center and the tailstock center are rotationally driven in synchronization with each other during heavy grinding, and the spindle center and 2. The cylindrical grinding machine according to claim 1, wherein the driving source is controlled so as to function as the dead center for supporting the workpiece in a state where the tailstock center is stopped. 3. 3. The cylinder according to claim 1, wherein the workpiece rotating means is a chip driving device that rotationally drives the workpiece via a chip attached to an end portion of the workpiece on the headstock side. Grinder. 3. The structure according to claim 1, wherein the tail pressing adjustment unit is configured to switch and adjust the axial centering load of the tailstock center in the tailstock between heavy grinding and finish grinding. 4. Cylindrical grinding machine. The center press adjusting means comprises a center press adjusting spring and a hydraulic cylinder for pressing the tail center against the tailstock in the axial direction,
The center pressing adjustment spring elastically urges the tail center with a predetermined pressure in the axial direction during the finish grinding, and the hydraulic cylinder presses the center center with the predetermined pressure during the heavy grinding. The cylindrical grinding machine according to claim 4, wherein the cylindrical grinding machine is configured to be biased with a predetermined pressure in the axial direction. The center pressing adjustment spring constantly and elastically biases the center pressing center with a predetermined pressure in the axial direction, and the hydraulic cylinder performs a resilient biasing action of the center pressing adjustment spring during the heavy grinding. The cylindrical grinding machine according to claim 5, wherein the cylindrical grinder is configured to additionally urge the tailstock center with a predetermined pressure in the axial direction in cooperation with the centering force. The hydraulic cylinder includes a work piece while the spindle center and the tailstock center are rotationally driven in synchronization with each other by a control unit that controls the spindle stock, the tailstock and the drive source in the spindle stock in conjunction with each other. Is activated when it functions as a live center that supports the workpiece, and the centering center is urged with a predetermined pressure in the axial direction, and the workpiece center is supported with the spindle center and the tailstock center stopped rotating. 6. The cylindrical grinder according to claim 5, wherein the cylinder grinder is stopped when functioning as a dead center. In the tailstock, the tailstock is supported by the tailstock housing so as to be rotatable and movable in the axial direction, and the tailstock center is detachably attached to the tip of the tailstock. And
The tailstock is drivingly coupled to the tailstock rotation drive source, and the tailstock rotation drive source is electrically connected to the control means,
The tail pressing adjustment spring that presses the tailstock shaft axially forward with respect to the tailstock housing is provided at a rear end portion of the tailstock shaft,
The hydraulic cylinder for reciprocating the tailstock shaft in the axial direction with respect to the tailstock housing is provided on the outer periphery of the tailstock shaft,
The cylindrical grinding machine according to claim 7, wherein a hydraulic pressure source and a pressure oil control valve of a hydraulic pressure supply device for reciprocating the piston of the hydraulic cylinder in the front-rear direction are electrically connected to the control means. 9. The cylindrical grinding machine according to claim 8, wherein the tailstock is supported by the tailstock housing so as to be rotatable and movable in an axial direction via a hydrostatic bearing. The mounting structure of both the centers in the headstock and the tailstock is provided with a tapered shank hole and a mounting end surface at the tip of the rotating shaft that is rotatable,
Thereby, both the centers are configured to be able to selectively adopt either a taper fitting mounting structure using the tapered shank hole or an end surface mounting structure using the mounting end surface. The cylindrical grinding machine according to claim 1, wherein A cylindrical grinding method for grinding an outer diameter surface of a workpiece by supporting the axial positions of both ends of the workpiece by the cylindrical grinding machine according to any one of claims 1 to 10,
A cylindrical grinding method, wherein the spindle center and the tailstock center are used as a live center, and the outer diameter surface of the workpiece is subjected to heavy grinding with the grinding wheel. A cylindrical grinding method for grinding an outer diameter surface of a workpiece by supporting the axial positions of both ends of the workpiece by the cylindrical grinding machine according to any one of claims 1 to 10,
A cylindrical grinding method, wherein the main spindle center and the tailstock center are used as dead centers, and the outer diameter surface of the workpiece is finish ground by the grinding wheel. A cylindrical grinding method for grinding an outer diameter surface of a workpiece by supporting the axial positions of both ends of the workpiece by the cylindrical grinding machine according to any one of claims 1 to 10,
The spindle center and the tailstock center are used as a live center, and the outer diameter surface of the workpiece is subjected to heavy grinding using the grinding wheel, and then the spindle center and the tailstock center are used as a dead center, and the grinding wheel is used to remove the workpiece. A cylindrical grinding method characterized by finish grinding an outer diameter surface. Prior to the heavy grinding, the spindle center and the tailstock center are used as live centers, and both the centers are ground in the machine by the grinding wheel so as to prevent live shake of these centers. Item 14. The cylindrical grinding method according to Item 11 or 13.

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