阅读说明：本技术 内球面磨床 (Internal spherical surface grinding machine ) 是由 许波 尚洪宝 刘平 李黎 李�荣 于 2019-08-21 设计创作，主要内容包括：一种内球面磨床,包括床身,床身上端安装摇摆臂,摇摆臂为由垂直轴、水平延伸部构成,水平延伸部上设有第一导轨,垂直轴下端通过第一带传动机构与正反转伺服电机连接,第一导轨上滑动配合磨盘主轴基座,磨盘主轴基座的磨盘主轴右端通过第二带传动机构与第一电机连接,磨盘通过安装轴与磨盘主轴左端连接固定,磨盘外圆周的斜面安装部设有多个磨条,水平延伸部上端固定驱动磨盘主轴基座的第一伺服电机,该伺服电机电机轴与第一螺杆连接,床身上端安装的第二导轨上滑动配合头架主轴基座,头架主轴左端通过第三带传动机构与第二电机连接,头架主轴右端固定工件夹具,床身上端安装驱动头架主轴基座的第二伺服电机,该伺服电机电机轴与第二螺杆连接。(An inner spherical surface grinding machine comprises a machine body, wherein a swing arm is arranged at the upper end of the machine body, the swing arm is composed of a vertical shaft and a horizontal extension part, a first guide rail is arranged on the horizontal extension part, the lower end of the vertical shaft is connected with a forward and reverse rotation servo motor through a first belt transmission mechanism, a grinding disc main shaft base is in sliding fit with the first guide rail, the right end of a grinding disc main shaft of the grinding disc main shaft base is connected with the first motor through a second belt transmission mechanism, a grinding disc is fixedly connected with the left end of the grinding disc main shaft through a mounting shaft, a plurality of grinding strips are arranged at the inclined surface mounting part of the outer circumference of the grinding disc, the first servo motor for driving the grinding disc main shaft base is fixed at the upper end of the horizontal extension part, a motor shaft is connected with a first screw rod, a headstock main shaft base is in sliding fit with, and a second servo motor for driving the headstock spindle base is arranged at the upper end of the lathe bed, and a motor shaft of the servo motor is connected with a second screw rod.)

1. The utility model provides an interior sphere grinding machine, includes lathe bed (25), its characterized in that: the grinding disc grinding machine is characterized in that a swing arm (8) is installed at the upper end of the machine body (25), the swing arm (8) is of a T-shaped structure formed by a vertical shaft (8-1) and a horizontal extending part (8-2) arranged at the upper end of the vertical shaft (8-1), a first guide rail (24) is arranged on the horizontal extending part (8-2), the vertical shaft (8-1) is matched with the machine body (25) through a bearing, the lower end of the vertical shaft (8-1) is connected with a forward and reverse rotation servo motor (11) through a first belt transmission mechanism (9), a grinding disc main shaft base (21) is matched with the first guide rail (24) in a sliding mode, the right end of a grinding disc main shaft (17) of the grinding disc main shaft base (21) is connected with a first motor (19) through a second belt transmission mechanism (18), and the axial lead of the grinding disc main shaft (17) is vertically intersected with the extension, a grinding disc (15) is fixedly connected with the left end of a grinding disc main shaft (17) through a mounting shaft (16), an inclined plane mounting part (15-1) is arranged on the outer circumference of the grinding disc (15) in a surrounding mode, a plurality of grinding strips (14) which are uniformly distributed on the circumference and used for grinding the inner spherical surface of a workpiece are arranged on the inclined plane mounting part (15-1), the rear extension end of the axial lead of each grinding strip (14) is intersected with the axial lead of the grinding disc main shaft (17) at the same point, a first servo motor (31) is fixed at the upper end of a horizontal extension part (8-2) of a swing arm (8), a motor shaft of the first servo motor (31) is fixedly connected with a first screw rod (6), the first screw rod (6) is in threaded fit connection with the grinding disc main shaft base (21), a second guide rail (7) is mounted at the upper end of a lathe bed (25), and the second guide rail (, the left end of a headstock main shaft (22) of the headstock main shaft base (4) is connected with a second motor (1) through a third belt transmission mechanism (2), a workpiece clamp (12) is fixedly mounted at the right end of the headstock main shaft (22), the axial lead of the headstock main shaft (22) and the axial lead of a grinding disc main shaft (17) are on the same horizontal plane and are vertically intersected with the axial lead extension line of a vertical shaft (8-1) of a swing arm (8), a second servo motor (30) is mounted at the upper end of a lathe bed (25), a motor shaft of the second servo motor (30) is fixedly connected with a second screw rod (5), and the second screw rod (5) is in threaded fit connection with the headstock main shaft base (4).

2. The internal sphere grinding machine of claim 1, wherein: the grinding disc is characterized in that a plurality of fixing holes (15-3) for mounting grinding bars (14) are uniformly distributed on the inclined surface mounting part (15-1) of the grinding disc (15), and the grinding bars (14) are inserted into the fixing holes (15-3) and are compressed and fixed through screws.

3. The internal sphere grinding machine of claim 1, wherein: the grinding disc (15) is provided with a central hole (15-2), and the left end of the mounting shaft (16) penetrates through the central hole (15-2) of the grinding disc (15) and is matched with a locking nut (23) to fix the grinding disc (15).

4. The internal sphere grinding machine of claim 1, wherein: the axis of the grinding disc main shaft (17) is provided with a Morse taper hole, the right end of the mounting shaft (16) is provided with a Morse taper shaft section, and the shaft section is inserted into the Morse taper hole to form Morse taper connection between the mounting shaft (16) and the grinding disc main shaft (17).

5. The internal sphere grinding machine of claim 1, wherein: the vertical shaft (8-1) of the swing arm (8) is arranged in a through hole (25-1) formed in the middle of the upper end of the bed body (25) through a bearing, the vertical shaft (8-1) is limited by a shaft shoulder, an end cover (27) is arranged at the lower end, located at the through hole (25-1), of the bed body (25), the end cover (27) abuts against the bearing to form limiting, and a center hole for the vertical shaft (8-1) to extend out is formed in the circle center of the end cover (27).

6. The internal sphere grinding machine of claim 1, wherein: millstone main shaft (17), headstock main shaft (22) support respectively through the bearing in bearing mounting hole (28) that set up on the base, a limiting plate (26) is fixed respectively to the left and right sides wall of each base, limiting plate (26) support the bearing and form spacingly, and each limiting plate (26) all is equipped with the hole of stepping down the main shaft.

7. The internal sphere grinding machine of claim 1, wherein: the first motor (1) is fixedly supported on a mounting bracket (29) through bolts, and the lower end of the mounting bracket (29) is fixedly connected with the grinding disc main shaft base (21).

8. The internal sphere grinding machine of claim 1, wherein: and the second motor (19) is fixed on the headstock spindle base (4) through a bolt.

9. The internal sphere grinding machine of claim 1, wherein: the workpiece clamp (12) is a three-jaw chuck or a four-jaw chuck.

Technical Field

The invention relates to a grinding machine, in particular to an internal spherical surface grinding machine.

Background

the ball valve is a key valve for cutting off media in a pipeline and comprises a ball body and a valve seat, wherein a sealing surface between the ball body and the valve seat is a spherical surface, and the sealing surface of the valve seat is an inner spherical surface. At present, the inner spherical surface of the valve seat seal is usually machined by turning the inner spherical surface through a lathe after being hardened, and because the machining precision of the lathe is not high, the size precision, the true sphericity and the roughness of the machined sealing surface can not meet the design precision requirement. Therefore, in order to achieve a good sealing effect, the ball body and the valve seat need to be manually ground, the processing period of the processing mode is long, the production efficiency is reduced, the number of required workers is large, and the production cost is increased. In addition, for the valve seat made of the supersonic spraying hard alloy, the bonding strength of the hard alloy layer of the valve seat and the substrate is low, and the sprayed hard alloy layer is also thin, so that the inner spherical surface of the valve seat cannot be turned on a lathe, and only a sealing surface can be machined in a grinding mode. At present, a sealing angle is ground, and then a valve seat and a ball body are mutually ground manually, so that the sealing requirement of the ball valve is met. The processing mode has the advantages of larger labor amount, longer processing time, greatly reduced production efficiency, great harm to batch production and reduced market competitiveness of manufacturers.

Disclosure of Invention

The invention aims to provide an inner spherical surface grinding machine aiming at the defects of the prior art, which can automatically process the inner spherical surface of a workpiece, greatly reduce the number of workers, reduce the production cost, have high grinding efficiency and precision of the inner spherical surface and improve the processing efficiency.

The technical scheme of the invention is as follows: an inner spherical surface grinding machine comprises a machine body, wherein a swing arm is arranged at the upper end of the machine body, the swing arm is of a T-shaped structure consisting of a vertical shaft and a horizontal extension part arranged at the upper end of the vertical shaft, a first guide rail is arranged on the horizontal extension part, the vertical shaft is matched with the machine body through a bearing, the lower end of the vertical shaft is connected with a forward and reverse servo motor through a first belt transmission mechanism, a grinding disc main shaft base is matched on the first guide rail in a sliding way, the right end of a grinding disc main shaft of the grinding disc main shaft base is connected with the first motor through a second belt transmission mechanism, the axial lead of the grinding disc main shaft is vertically crossed with the axial extension line of the vertical shaft of the swing arm, a grinding disc is fixedly connected with the left end of the grinding disc main shaft through a mounting shaft, an inclined surface mounting part is arranged, the rear extension end of the axial lead of each grinding strip is intersected with the axial lead of the main shaft of the grinding disc at the same point, a first servo motor is fixed at the upper end of the horizontal extension part of the swing arm, a motor shaft of the first servo motor is fixedly connected with a first screw rod which is in threaded fit connection with the grinding disc main shaft base, the upper end of the lathe bed is provided with a second guide rail which is in sliding fit with the headstock main shaft base, the left end of the headstock main shaft base is connected with a second motor through a third belt transmission mechanism, the right end of the headstock main shaft is fixedly provided with a workpiece clamp, the axis of the headstock main shaft and the axis of the grinding disc main shaft are on the same horizontal plane, and is vertically crossed with the extended line of the axis of the vertical shaft of the swing arm, a second servo motor is arranged at the upper end of the lathe bed, the motor shaft of the second servo motor is fixedly connected with a second screw rod, and the second screw rod is in threaded fit connection with the headstock spindle base.

The grinding disc is characterized in that a plurality of fixing holes for installing grinding strips are uniformly distributed on the inclined surface installing part of the grinding disc in the circumferential direction, and the grinding strips are inserted into the fixing holes and are pressed and fixed through screws.

The mill is equipped with a centre of circle hole, the installation axle left end passes the mill centre of circle hole and a lock nut cooperation fixed mill.

The grinding disc spindle is characterized in that a Morse taper hole is formed in the axis of the grinding disc spindle, a Morse taper shaft section is arranged at the right end of the mounting shaft and inserted into the Morse taper hole, and Morse taper connection of the mounting shaft and the grinding disc spindle is formed.

The vertical shaft of the swing arm is arranged in a through hole formed in the middle of the upper end of the lathe bed through a bearing, the vertical shaft passes through a shaft shoulder limiting bearing, an end cover is arranged at the lower end of the through hole of the lathe bed and abuts against the bearing to form limiting, and a center hole for the vertical shaft to extend out is formed in the circle center of the end cover.

The grinding disc main shaft and the headstock main shaft are supported in bearing mounting holes formed in the bases through bearings respectively, a limiting plate is fixed to the left side wall and the right side wall of each base respectively, the limiting plates abut against the bearings to form limiting, and holes for yielding the main shafts are formed in each limiting plate.

The first motor is fixedly supported on a mounting bracket through bolts, and the lower end of the mounting bracket is fixedly connected with the grinding disc main shaft base.

And the second motor is fixed on the headstock spindle base through a bolt.

The workpiece clamp is a three-jaw chuck or a four-jaw chuck.

Adopt above-mentioned technical scheme: the grinding disc grinding machine comprises a machine body, wherein a swing arm is arranged at the upper end of the machine body, the swing arm is of a T-shaped structure consisting of a vertical shaft and a horizontal extension part arranged at the upper end of the vertical shaft, a first guide rail is arranged on the horizontal extension part, the vertical shaft is matched with the machine body through a bearing, the lower end of the vertical shaft is connected with a forward and reverse servo motor through a first belt transmission mechanism, a grinding disc main shaft base is matched and glidingly matched with the first guide rail, the right end of a grinding disc main shaft of the grinding disc main shaft base is connected with the first motor through a second belt transmission mechanism, the axial lead of the grinding disc main shaft is vertically crossed with the axial lead extension line of the vertical shaft of the swing arm, a grinding disc is fixedly connected with the left end of the grinding disc main shaft through a mounting shaft, an inclined plane mounting part is arranged around the outer circumference of the grinding disc, a plurality of grinding bars which, the upper end of the horizontal extension part of the swing arm is fixedly provided with a first servo motor, a motor shaft of the first servo motor is fixedly connected with a first screw rod, the first screw rod is in threaded fit connection with the grinding disc main shaft base, the upper end of the lathe body is provided with a second guide rail, the second guide rail is in sliding fit with the headstock main shaft base, the left end of a headstock main shaft of the headstock main shaft base is connected with a second motor through a third belt transmission mechanism, the right end of the headstock main shaft is fixedly provided with a workpiece clamp, the axial lead of the headstock main shaft and the axial lead of the grinding disc main shaft are on the same straight line, the upper end of the lathe body is provided with a second servo motor, the motor shaft of the second servo motor is fixedly connected with a second screw rod, and the second screw. Wherein each motor all is connected with controller PLC electricity, through PLC alright control the work of each motor for but this grinding machine automatic processing work piece's interior sphere, automatic processing significantly reduced workman's quantity, only need the operative employee of a grinding machine can, greatly reduced manufacturing cost. When the numerical control lathe works, a workpiece to be machined is fixed on the workpiece clamp, and then the headstock spindle base is driven by the second servo motor to slide on the second guide rail, so that the workpiece stays at a proper grinding position. Then according to the grinding width of the inner spherical surface of the workpiece, the swing angle of the forward and reverse rotation servo motor is set, a proper grinding disc is selected, the grinding strips with required quantity are installed on the grinding disc, and then the grinding disc is installed on the installation shaft. Then, the grinding disc main shaft base is driven by the first servo motor to slide on the first guide rail, so that the grinding disc stays at a proper grinding position, and at the moment, each grinding strip is perpendicular to the inner spherical surface of the workpiece. After the adjustment is completed, the positive and negative rotation period of the positive and negative rotation servo motor is set through the PLC, and then the first motor, the second motor and the positive and negative rotation servo motor are started to work. At the moment, the second motor drives the workpiece to rotate, the first motor drives the grinding disc to rotate, the forward and reverse servo motors drive the swing arm to swing around the axial lead of the vertical shaft so that the grinding disc swings in an arc shape, and the workpiece moves along the second guide rail through the driving feeding of the second servo motor in the grinding process, so that the grinding depth of the workpiece can be adjusted; the grinding disc moves along the first guide rail through the driving feeding of the first servo motor, the grinding radius of the inner spherical surface of the workpiece can be properly adjusted, and the grinding disc can be used for abrasive wear compensation, so that the automatic processing of the inner spherical surface of the workpiece is realized. The grinding machine has high machining precision, and the size precision, the true sphericity and the roughness of the machined inner spherical surface can meet the precision requirement of a workpiece. Moreover, the processing efficiency is high, the processing period is greatly shortened, the batch production is facilitated, the production efficiency is improved, the qualification rate of the produced product is higher compared with that of manual grinding, and the market competitiveness is improved. The grinding machine is suitable for processing the inner spherical surface of the ball valve seat, the ball valve seat made of the supersonic spraying hard alloy can be directly ground, the precision of the ground inner spherical surface of the valve seat is high, and the high sealing performance of the ball valve is ensured. In addition, because the grinding bars are always vertical to the inner spherical surface of the workpiece, the grinding bars do not need to be trimmed in the grinding process, and the ideal grinding effect can be achieved.

The grinding disc is characterized in that a plurality of fixing holes for installing grinding strips are uniformly distributed on the inclined surface installing part of the grinding disc in the circumferential direction, and the grinding strips are inserted into the fixing holes and are pressed and fixed through screws. The grinding strip is simple and convenient to mount and dismount, and when the inner spherical surfaces of different workpieces are machined, the corresponding grinding disc is selected according to the diameter of the inner spherical surface.

The mill is equipped with a centre of circle hole, the installation axle left end passes the mill centre of circle hole and a lock nut cooperation fixed mill. The connection between the grinding disc and the mounting shaft is simple, and the grinding disc is axially limited on the mounting shaft through a shaft shoulder.

the grinding disc spindle is characterized in that a Morse taper hole is formed in the axis of the grinding disc spindle, a Morse taper shaft section is arranged at the right end of the mounting shaft and inserted into the Morse taper hole, and Morse taper connection of the mounting shaft and the grinding disc spindle is formed. The mounting shaft and the main shaft of the grinding disc form quick clamping, so that the grinding disc and the grinding strip can be conveniently replaced, and the processing efficiency is improved.

The vertical shaft of the swing arm is arranged in a through hole formed in the middle of the upper end of the lathe bed through two bearings, an axial limiting sleeve is arranged between the two bearings, the vertical shaft is limited by a shaft shoulder, an end cover is arranged at the lower end of the through hole of the lathe bed and abuts against the bearings to form limiting, and a center hole for the vertical shaft to extend out is formed in the circle center of the end cover. The swing arm is in running fit with the bed body, and the swing arm is well matched with the bed body.

The grinding disc main shaft and the headstock main shaft are supported in bearing mounting holes formed in the base through two bearings respectively, an axial limiting sleeve is arranged between the two bearings, a limiting plate is fixed to the left side wall and the right side wall of each base respectively, the limiting plates abut against the bearings to form limiting, and holes of yielding main shafts are formed in each limiting plate. The grinding disc main shaft and the head frame main shaft are rotatably arranged on the base, and the support rigidity and the strength of the main shafts on the base are good.

The first motor is fixedly supported on a mounting bracket through bolts, the lower end of the mounting bracket is fixedly connected with the grinding disc main shaft base, and the mounting bracket facilitates the mounting of the first motor.

The second motor is fixed on the headstock spindle base through a bolt, and the second motor is convenient to mount.

The workpiece fixture is a three-jaw chuck or a four-jaw chuck, and the three-jaw chuck or the four-jaw chuck consists of a chuck body, a movable jaw and a jaw driving mechanism, so that the center can be quickly found, and the clamping time of the workpiece is saved.

The inner spherical surface of the workpiece can be automatically processed by the inner spherical surface grinding machine, the number of workers is greatly reduced by automatic processing, only one operator of the grinding machine is needed, and the production cost is greatly reduced. The grinding machine has high machining precision, and the size precision, the true sphericity and the roughness of the machined inner spherical surface can meet the grinding precision requirement. Moreover, the processing efficiency is high, the processing period is greatly shortened, the batch production is facilitated, the production efficiency is improved, the qualification rate of the produced product is higher compared with that of manual grinding, and the market competitiveness is improved.

The invention is further described with reference to the drawings and the specific embodiments in the following description.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the swing arm;

Fig. 3 is a schematic structural diagram of the grinding disc.

In the drawing, 1 is a second motor, 2 is a third belt transmission mechanism, 3 is a third driven pulley, 4 is a headstock spindle base, 5 is a second screw, 6 is a first screw, 7 is a second guide rail, 8 is a swing arm, 8-1 is a vertical shaft, 8-2 is a horizontal extension portion, 9 is a first belt transmission mechanism, 10 is a first driven pulley, 11 is a forward and reverse servo motor, 12 is a workpiece holder, 13 is a valve seat, 14 is a grinding strip, 15 is a grinding disc, 15-1 is a bevel mounting portion, 15-2 is a circular center hole, 15-3 is a fixed hole, 16 is a mounting shaft, 17 is a grinding disc spindle, 18 is a second belt transmission mechanism, 19 is a first motor, 20 is a second driven pulley, 21 is a grinding disc spindle base, 22 is a headstock spindle, 23 is a lock nut, 24 is a first guide rail, 25 is a lathe bed, 25-1 is a through hole, 26 is a limit plate, 27 is an end cover, 28 is a bearing mounting hole, 29 is a mounting bracket, 30 is a second servo motor, and 31 is a first servo motor.

Detailed Description

Referring to fig. 1 to 3, the internal sphere grinding machine comprises a machine body 25, wherein a swing arm 8 is mounted at the upper end of the machine body 25, and the swing arm 8 is of a T-shaped structure formed by a vertical shaft 8-1 and a horizontal extension part 8-2 arranged at the upper end of the vertical shaft 8-1. The horizontal extension part 8-2 is provided with a first guide rail 24, the vertical shaft 8-1 is matched with a through hole 25-1 arranged in the middle of the upper end of the bed body 25 through two bearings, the upper end of the vertical shaft 8-1 is limited by a shaft shoulder, the lower end of the bed body 25, which is positioned at the through hole 25-1, is provided with an end cover 27 through a bolt, the end cover 27 abuts against the bearing to form limitation, the center of the end cover 27 is provided with a central hole for the vertical shaft 8-1 to extend out, the swing arm 8 is rotatably matched in the through hole 25-1 of the bed body 25, and the swing arm 8 is matched with the. The lower end of the vertical shaft 8-1 is connected with a positive and negative rotation servo motor 11 through a first belt transmission mechanism 9, a first driven belt pulley 10 of the first belt transmission mechanism 9 is circumferentially fixed with the lower end of the vertical shaft 8-1 through a key, a nut for limiting the first driven belt pulley 10 is installed at the lower end of the vertical shaft 8-1, a driving belt pulley of the first belt transmission mechanism 9 is fixedly connected with a motor shaft of the positive and negative rotation servo motor 11, and the positive and negative rotation servo motor 11 is fixed on the lathe bed 25 through a bolt. The grinding disc main shaft base 21 is matched with the first guide rail 24 in a sliding mode, the right end of a grinding disc main shaft 17 of the grinding disc main shaft base 21 is connected with the first motor 19 through the second belt transmission mechanism 18, and the first motor 19 is a stepless speed regulating motor. The first motor 19 is fixedly supported on a mounting bracket 29 through bolts, the lower end of the mounting bracket 29 is fixedly connected with the grinding disc main shaft base 21, and the mounting bracket 29 facilitates the mounting of the first motor 19. A second driven belt pulley 20 of the second belt transmission mechanism 18 is circumferentially fixed with the right end of the grinding disc main shaft 17 through a key, and a driving belt pulley of the second belt transmission mechanism 18 is fixedly connected with a motor shaft of the first motor 19. The axial lead of the grinding disc main shaft 17 is vertically crossed with the axial extension line of the vertical shaft 8-1 of the swing arm 8, a grinding disc 15 is fixedly connected with the left end of the grinding disc main shaft 17 through a mounting shaft 16, the axial lead of the grinding disc main shaft 17 is provided with a Morse taper hole, the right end of the mounting shaft 16 is provided with a Morse taper shaft section, and the shaft section is inserted into the Morse taper hole to form Morse taper connection of the mounting shaft 16 and the grinding disc main shaft 17. Alternatively, other conventionally used quick-clamping connections between the mounting shaft 16 and the disc spindle 17 may be used. The present embodiment selects to connect the mounting shaft 16 with the grinding disc main shaft 17 by morse taper. The mounting shaft 16 and the grinding disc main shaft 17 form quick clamping, so that the grinding disc 15 is convenient to replace, and the processing efficiency is improved. The grinding disc 15 is provided with a central hole 15-2, and the left end of the mounting shaft 16 penetrates through the central hole 15-2 of the grinding disc 15 and is matched with a locking nut 23 to fix the grinding disc 15. The connection between the grinding disc 15 and the mounting shaft 16 is also simple, and the grinding disc 15 is axially limited on the mounting shaft 16 by a shaft shoulder. The outer circumference of the grinding disc 15 is provided with an inclined plane mounting part 15-1 in a surrounding way, and the inclined plane mounting part 15-1 is provided with a plurality of grinding bars 14 for grinding the inner spherical surface of the valve seat 13. The bevel mounting part 15-1 of the grinding disc 15 is provided with a plurality of fixing holes 15-3 for mounting the grinding strips 14, the grinding strips 14 are uniformly distributed on the circumference, the grinding strips are inserted into the fixing holes 15-3 and are compressed and fixed through screws, the screws are in threaded fit with threaded holes arranged on the bevel mounting part 15-1, and each threaded hole is perpendicular to the fixing hole 15-3. The installation and the dismantlement of abrasive stick 14 are simple and convenient, have made things convenient for the change of abrasive stick 14, when processing different disk seats 13 inner spherical surfaces, the size according to inner spherical surface diameter selects corresponding mill 15 can. The rear extending end of the axial lead of each grinding strip 14 is intersected with the axial lead of the grinding disc main shaft 17 at the same point, a first servo motor 31 is fixed at the upper end of a horizontal extending part 8-2 of the swing arm 8, a motor shaft of the first servo motor 31 is fixedly connected with a first screw rod 6, and the first screw rod 6 is in threaded fit connection with a nut fixed on the grinding disc main shaft base 21. The headstock spindle 22 of the headstock spindle base 4 is connected at the left end thereof with the second motor 1 through the third belt transmission mechanism 2, the second motor 1 is a stepless speed regulating motor, the second motor 1 is fixed on the headstock spindle base 4 through bolts, and the second motor 1 is also convenient to mount. The third driven pulley 3 of the third belt transmission mechanism 2 is circumferentially and fixedly connected with the headstock spindle 22 through a key, and the driving pulley of the third belt transmission mechanism 2 is fixedly connected with the motor shaft of the second motor 1. The workpiece fixture 12 is fixedly mounted at the right end of the headstock spindle 22, and the workpiece fixture 12 is a three-jaw chuck or a four-jaw chuck, or may also be a tool fixture which is conventionally used on a machine tool, and is selected as the workpiece fixture of the three-jaw chuck in the embodiment. The three-jaw chuck consists of a chuck body, movable jaws and a jaw driving mechanism, can quickly find the center, and saves the clamping time when the valve seat 13 is ground. The axis of the headstock spindle 22 and the axis of the grinding disc spindle 17 are on the same horizontal plane and are vertically crossed with the axis extension line of the vertical shaft 8-1 of the swing arm 8. The grinding disc main shaft 17 and the headstock main shaft 22 are supported in bearing mounting holes 28 arranged on corresponding bases through two bearings respectively, axial limiting sleeves are sleeved on the main shafts respectively and located between the two bearings, limiting plates 26 are fixed on the left side wall and the right side wall of each base respectively, and the limiting plates 26 abut against the bearings supporting the main shafts to limit the bearings. Each limit plate 26 is provided with a hole of an abdicating main shaft, the grinding disc main shaft 17 and the headstock main shaft 22 are rotatably arranged on the corresponding base, and the support rigidity and the strength of each main shaft on the base are good. The upper end of the lathe bed 25 is provided with a second servo motor 30, a motor shaft of the second servo motor 30 is fixedly connected with a second screw rod 5, and the second screw rod 5 is in threaded fit connection with a nut fixed on the headstock spindle base 4. The positions of the grinding disc main shaft base 21 and the headstock main shaft base 4 are simple and convenient to adjust and can be controlled by a PLC (programmable logic controller), and the positions of the grinding disc main shaft base 21 and the headstock main shaft base 4 are more accurate. Each motor is electrically connected with the controller PLC, and the work of each motor can be controlled through the PLC.

The inner spherical surface of the workpiece valve seat 13 can be automatically processed by the inner spherical surface grinding machine, the number of workers is greatly reduced by automatic processing, only one operator of the grinding machine is needed, and the production cost is greatly reduced. During working, the valve seat 13 to be machined is fixed on the three-jaw chuck, the second servo motor 30 is controlled by the PLC to work, the second screw 5 is driven to rotate, and therefore the headstock spindle base 4 in threaded fit with the second screw 5 is driven to slide on the second guide rail 7, and the valve seat 13 is stopped at a proper grinding position. The spherical centers of the inner spherical surfaces of the valve seats 13 with different sizes are always fixed at the intersection point of the extension line of the vertical shaft 8-1 axis of the swing arm 8 and the extension line of the axis of the grinding disc main shaft 17. Then, according to the grinding width of the inner spherical surface of the valve seat 13, the forward and reverse rotation period of the forward and reverse rotation servo motor 11 is set through the PLC, namely, the swing angle of the forward and reverse rotation servo motor 11 is set, a proper grinding disc 15 is selected, the grinding strips 14 in required number are installed on the grinding disc 15, and then the grinding disc 15 is installed on the installation shaft 16, wherein the number of the grinding strips is preferably 2-8. Then, the first servo motor 31 is controlled by the PLC to work, and the first screw 6 is driven to rotate, so that the grinding disc spindle base 21 in threaded fit with the first screw 6 is driven to slide on the first guide rail 24, and the grinding disc spindle base 21 is stopped at a proper grinding position. At this time, each of the bars 14 is perpendicular to the inner spherical surface of the valve seat 13. After the adjustment is completed, the first motor, the second motor and the forward and reverse rotation servo motor 11 are started to work. At the moment, the second motor 1 drives the valve seat 13 to rotate, the first motor 19 drives the grinding disc 15 to rotate, the forward and reverse rotation servo motor 11 drives the swing arm 8 to swing around the axis line of the vertical shaft 8-1 so as to enable the grinding disc 15 to do circular arc swing, and in the grinding process, the workpiece is driven to move along the second guide rail 7 through the driving feeding of the second servo motor 30, so that the grinding depth of the workpiece can be adjusted; the grinding radius of the inner spherical surface of the workpiece can be properly adjusted by moving the grinding disc 15 along the first guide rail 24 by the driving feed of the first servo motor 31, and the grinding disc can be used for abrasive wear compensation, thereby realizing the automatic processing of the inner spherical surface of the valve seat 13. The grinding machine has high machining precision, and the size precision, the true sphericity and the roughness of the machined inner spherical surface can meet the grinding precision requirement. Moreover, the processing efficiency is high, the processing period is greatly shortened, the batch production is facilitated, the production efficiency is improved, the qualification rate of the produced product is higher compared with that of manual grinding, and the market competitiveness is improved. The grinding machine is suitable for processing the inner spherical surface of the ball valve seat and grinding other inner spherical surface parts, can directly grind the ball valve seat made of the supersonic spraying hard alloy, has high precision of the ground inner spherical surface of the valve seat 13, and ensures the high sealing performance of the ball valve. And because the grinding strip 14 is always vertical to the inner spherical surface of the valve seat, the grinding strip 14 does not need to be trimmed in the grinding process, and the ideal grinding effect can be achieved.