A pressure wheel device without center hole

Abstract

The utility model belongs to the technical field of grinding machines, and particularly refers to a center hole-free pressure wheel device; it comprises a first guide wheel seat and a second guide wheel seat which are arranged side by side, a first spindle is rotatably arranged in the first guide wheel seat, and a second spindle is rotatably arranged in the second guide wheel seat, one end of the first spindle and the second spindle are driven to rotate synchronously by a first driving mechanism, and the other end is respectively provided with a first guide wheel and a second guide wheel, a placement position for a workpiece is formed between the first guide wheel and the second guide wheel, a workpiece adjustment frame is arranged on the first guide wheel seat and the second guide wheel seat, a limiting rod which abuts against one end of the workpiece is arranged on the workpiece adjustment frame, a second driving mechanism is arranged on one side of the first guide wheel seat or the second guide wheel seat, the second driving mechanism is connected to the pressure wheel seat, and a pressure wheel which can be pressed onto the workpiece is arranged on the pressure wheel seat; the utility model can be used in conjunction with an ordinary external cylindrical grinder to process a workpiece without a center hole, and can greatly reduce the processing cost compared with the need to use centerless grinding in the prior art.

Description

Technical field:

[0001] The utility model belongs to the technical field of grinding machines, in particular to a pressure wheel device without a center hole. Background technology:

[0002] Cylindrical grinders are machines that can process various cylindrical, conical and other shaped external surfaces and shoulder end faces. Usually, ordinary cylindrical grinders can process workpieces with center holes. Workpieces without center holes need to be processed using centerless grinders, but the price of centerless grinders is high, which undoubtedly increases the processing cost. Most centerless grinders cannot process stepped shafts without center holes. Even if they can be processed, there are defects such as small processing range and high cost, and the applicability is not wide. Summary of the invention:

[0003] The utility model aims to provide a center-hole-free pressing wheel device which can be used in conjunction with a common cylindrical grinder to process a workpiece without a center hole, especially a stepped shaft without a center hole.

[0004] The utility model is achieved in this way:

[0005] A center hole-free pressure wheel device comprises a first guide wheel seat and a second guide wheel seat which are arranged side by side, a first spindle is rotatably arranged in the first guide wheel seat, and a second spindle is rotatably arranged in the second guide wheel seat, the first spindle and the second spindle are arranged in parallel, one end of the first spindle and the second spindle are driven to rotate synchronously by a first driving mechanism, and the other end is respectively provided with a first guide wheel and a second guide wheel, a placement position for a workpiece is formed between the first guide wheel and the second guide wheel, a workpiece adjustment frame is arranged on the first guide wheel seat and the second guide wheel seat, a limiting rod which abuts against one end of the workpiece is arranged on the workpiece adjustment frame, a second driving mechanism is arranged on one side of the first guide wheel seat or the second guide wheel seat, the second driving mechanism is connected to the pressure wheel seat, and a pressure wheel which can be pressed on the workpiece is arranged on the pressure wheel seat.

[0006] In the above-mentioned pressure wheel device without a center hole, a support rod is also provided on the base, and the support rod is located between the first guide wheel seat and the second guide wheel seat.

[0007] In the above-mentioned center hole-free pressure wheel device, the first driving mechanism includes a first driven wheel, a second driven wheel, and a driving motor. A driving wheel is arranged on the driving motor. The driving wheel, the first driven wheel, and the second driven wheel are connected by a synchronous belt transmission. The driving motor drives the driving wheel to rotate, and drives the first driven wheel and the second driven wheel to rotate through the synchronous belt.

[0008] In the above-mentioned center-hole-free pressure wheel device, the workpiece adjustment frame includes a workpiece adjustment plate, strip holes are provided at both ends of the workpiece adjustment plate, the long axis of the strip hole is provided perpendicular to the first main axis, the workpiece adjustment plate is screwed to the first guide wheel seat and the second guide wheel seat by screws passing through the strip holes, and the workpiece adjustment plate can adjust the position along the long axis direction, a workpiece adjustment block is provided on the workpiece adjustment plate, a through hole matching the shape of the limit rod is provided on the workpiece adjustment block, and threaded holes connecting the through holes are provided on the workpiece adjustment plate and the workpiece adjustment block, the screws are screwed in the threaded holes and the inner ends thereof abut against the limit rod to lock the limit rod.

[0009] In the above-mentioned center hole-free pressing wheel device, a roller is arranged at one end of the limiting rod, and a roller sleeve is sleeved outside the roller to abut against the workpiece.

[0010] In the above-mentioned center hole-free pressure wheel device, the second driving mechanism includes a lower guide rail bracket, a lower guide rail and a first cylinder are arranged on the lower guide rail bracket, the lower guide rail is arranged perpendicular to the first main axis, the upper guide rail bracket is slidably connected to the lower guide rail, the piston rod of the first cylinder is connected to the upper guide rail bracket, the upper guide rail and the second cylinder arranged along the up and down directions are arranged on the upper guide rail bracket, the piston of the second cylinder is arranged along the up and down directions, the drag plate is slidably arranged on the upper guide rail, the pressure wheel block is fixed on the drag plate, the drag plate is driven up and down by the second cylinder, the upper end of the pressure wheel seat is connected to the pressure wheel block, and the pressure wheel is arranged at the lower end.

[0011] In the above-mentioned center hole-free pressure wheel device, the first main shaft and the second main shaft include an axle body, a first shaft body and a second shaft body at the rear end of the axle body, and a third shaft body and a fourth shaft body are sequentially arranged at the front end of the axle body, the diameter of the axle body is greater than the diameter of the first shaft body and the diameter of the second shaft body, a first step surface is formed between the axle body and the first shaft body, a second step surface is formed between the first shaft body and the second shaft body, the diameter of the axle body is less than the third shaft body, and a third step surface is formed between the axle body and the third shaft body.

[0012] In the above-mentioned pressure wheel device without a center hole, a rear bearing, a rear bearing retaining ring, a rear locking ring and a rear limit piece are sequentially mounted on the first shaft body from front to rear, and a rear end cover is arranged on the rear end faces of the first guide wheel seat and the second guide wheel seat, and the rear bearing retaining ring passes through the rear end cover and rests on the rear bearing, and a plurality of threaded holes are evenly distributed circumferentially on the rear locking ring, and screws are screwed into the threaded holes and rest on the rear bearing retaining ring, and a sealing ring is arranged between the rear bearing retaining ring and the rear end cover, and the rear limit piece is tightly against the rear end of the rear locking ring.

[0013] In the above-mentioned center hole-free pressure wheel device, the front end of the shaft body is provided with a front bearing, a front bearing retaining ring, a front locking ring and a front limit piece in sequence from front to rear. The front locking ring is provided with a plurality of threaded holes evenly distributed circumferentially. The screws are threaded in the threaded holes and abut against the front bearing retaining ring. The front limit piece is close to the rear end of the front locking ring.

[0014] In the above-mentioned pressure wheel device without a center hole, the fourth axis is a frustum of a cone, and a conical hole matching the frustum of the cone is arranged in the first guide wheel or the second guide wheel. The first guide wheel or the second guide wheel is mounted on the fourth axis and fixedly connected to the end face of the fourth axis by gaskets and screws.

[0015] The outstanding advantages of the utility model compared with the prior art are:

[0016] 1. The utility model can be used in conjunction with an ordinary cylindrical grinder to process workpieces without center holes. Compared with the prior art, which requires the use of centerless grinding, especially for stepped shafts without center holes, the processing cost can be greatly reduced and the applicability can be improved;

[0017] 2. The distance between the first guide wheel seat and the second guide wheel seat of the utility model is adjustable, and the first guide wheel and the second guide wheel can also be replaced to match the processing of different workpieces, thereby improving the versatility of processing;

[0018] 3. One end of the workpiece of the utility model abuts against the limit rod and is supported by the support rod, and the other end is pressed by the pressure wheel, so that high-precision positioning of the workpiece is achieved and high processing accuracy is achieved. Description of the drawings:

[0019] Figure 1 It is a three-dimensional schematic diagram of the utility model;

[0020] Figure 2 It is a top view of the utility model;

[0021] Figure 3 It is a cross-sectional schematic diagram of the utility model;

[0022] Figure 4 It is the front view of the utility model;

[0023] Figure 5 It is a left view of the utility model;

[0024] Figure 6 yes Figure 5 A magnified schematic diagram of part A;

[0025] Figure 7 It is a right view of the utility model;

[0026] Figure 8 It is a schematic diagram of the utility model being arranged on a slide;

[0027] Fig. 9 It is a schematic diagram of the first main axis of the utility model;

[0028] Fig.10 It is a schematic diagram of the limit rod of the utility model being installed on the workpiece adjustment frame.

[0029] In the figure: 1, base; 2, first guide wheel seat; 3, second guide wheel seat; 4, first spindle; 5, first guide wheel; 6, second guide wheel; 7, workpiece; 8, workpiece adjustment frame; 9, limit rod; 10, pressure wheel seat; 11, pressure wheel; 12, first driven wheel; 13, second driven wheel; 14, drive motor; 15, synchronous belt; 16, workpiece adjustment plate; 17, strip hole; 18, workpiece adjustment block; 19, threaded hole; 20, roller sleeve; 21, lower guide rail bracket; 22, lower guide rail; 23, upper guide rail bracket; 24, first cylinder; 25, lower push plate; 26, second cylinder; 27. Push plate; 28. Drag plate; 29. ​​Pressure wheel block; 30. Axle body; 31. First axle body; 32. Second axle body; 33. Third axle body; 34. Fourth axle body; 35. First step surface; 36. Second step surface; 37. Third step surface; 38. Rear bearing; 39. Rear bearing retaining ring; 40. Rear locking ring; 41. Rear limit piece; 42. Rear end cover; 43. Sealing ring; 44. Front bearing; 45. Front bearing retaining ring; 46. Front locking ring; 47. Front limit piece; 48. Gasket; 49. Support rod; 50. Pressure wheel core shaft; 51. Pressure wheel end cover; 51. Slide table. Specific implementation method:

[0030] The present invention is further described below with specific embodiments:

[0031] like Figure 1-10 As shown, the utility model provides a center-hole-free pressure wheel device, which includes a first guide wheel seat 2 and a second guide wheel seat 3 arranged side by side on a base 1, a first spindle 4 is rotatably arranged in the first guide wheel seat 2, and a second spindle is rotatably arranged in the second guide wheel seat 3, the first spindle 4 and the second spindle are arranged in parallel, one end of the first spindle 4 and the second spindle are driven to rotate synchronously by a first driving mechanism, and the other end is respectively provided with a first guide wheel 5 and a second guide wheel 6, a placement position for a workpiece 7 is formed between the first guide wheel 5 and the second guide wheel 6, a workpiece adjustment frame 8 is arranged on the first guide wheel seat 2 and the second guide wheel seat 3, a limiting rod 9 is arranged on the workpiece adjustment frame 8, a supporting rod 49 for supporting one end of the workpiece 7 is arranged on the base 1, a second driving mechanism is arranged on one side of the first guide wheel seat 2 or the second guide wheel seat 3, the second driving mechanism is connected to the pressure wheel seat 10, and the pressure wheel seat 10 is provided with a pressure wheel 11 that can be pressed on the workpiece 7. The pressure wheel 11 is driven by the second driving mechanism to move to the upper side of the placement position and then presses down on the workpiece 7. In the present utility model, the pressure wheel 11 adopts a bearing. The specific connection structure between the pressure wheel 11 and the pressure wheel seat 10 is as follows: Figure 6 As shown, a groove with an opening facing downward is provided at the lower end of the pressure wheel seat 10 , and the pressure wheel 11 is arranged in the groove through the pressure wheel core shaft 50 and the pressure wheel end cover 51 .

[0032] The utility model is installed on a common cylindrical grinder. When in use, one end of the workpiece 7 is placed against the limit rod 9, and the other end is placed in the placement position between the first guide wheel 5 and the second guide wheel 6. The part of the workpiece 7 that needs to be ground extends out of the first guide wheel 5 and the second guide wheel 6. If necessary, one end of the workpiece 7 is also supported by the support rod 49. The second driving mechanism drives the pressure wheel 11 to move above the other end of the workpiece 7, and finally drives the pressure wheel 11 to be pressed on the other end of the workpiece 7. Cooperate with the measuring instrument to ensure that the axial position of the workpiece 7 meets the processing requirements. The action of the first driving mechanism drives the first spindle 4 and the second spindle to rotate, and finally drives the first guide wheel 5 and the second guide wheel 6 to rotate synchronously. The first guide wheel 5, the second guide wheel 6, and the pressure wheel 11 drive the workpiece 7 to rotate, and the grinding wheel grinds the grinding part of the workpiece 7 until the grinding work is completed.

[0033] It should be noted that the distance between the first guide wheel seat 2 and the second guide wheel seat 3 of the utility model can be adjusted by setting strip holes whose axes are perpendicular to the first main shaft 4 and the second main shaft on the first guide wheel seat 2 and the second guide wheel seat 3, and the first guide wheel 5 and the second guide wheel 6 can also be replaced to cooperate with the processing of different workpieces, thereby improving versatility.

[0034] The utility model can realize the clamping of workpieces without center holes, so that ordinary cylindrical grinders can realize the processing of workpieces without center holes, especially stepped shafts without center holes. Compared with the prior art, which requires the use of centerless grinders to process workpieces without center holes, the processing cost is greatly reduced.

[0035] like Figure 1-Figure 3 , Figure 5 , Figure 7 and Figure 8 As shown, the first driving mechanism includes a first driven wheel 12, a second driven wheel 13, and a driving motor 14. A driving wheel is arranged on the driving motor 14. The driving wheel, the first driven wheel 12, and the second driven wheel 13 are connected through a synchronous belt 15. The driving motor 14 drives the driving wheel to rotate, and drives the first driven wheel 12 and the second driven wheel 13 to rotate through the synchronous belt 15.

[0036] In addition, the first driving mechanism of the present invention can also be implemented by a gear transmission mechanism.

[0037] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Fig.10As shown, the workpiece adjustment frame 8 includes a workpiece adjustment plate 16, and strip holes 17 are provided at both ends of the workpiece adjustment plate 16. The long axis of the strip hole 17 is perpendicular to the first spindle 4. The workpiece adjustment plate 16 is screwed to the first guide wheel seat 2 and the second guide wheel seat 3 through screws passing through the strip holes 17, and the workpiece adjustment plate 16 can adjust the position along the long axis direction. A workpiece adjustment block 18 is provided on the workpiece adjustment plate 16, and a through hole matching the shape of the limit rod 9 is provided on the workpiece adjustment block 18. A threaded hole 19 connected to the through hole is provided on the workpiece adjustment plate 16 and the workpiece adjustment block 18. The screw is screwed in the threaded hole 19 and its inner end abuts against the limit rod 9 to lock the limit rod 9. The limit plate 9 can adjust its position along its axial direction to facilitate the use with workpieces 7 of different lengths.

[0038] In order to reduce the friction during rotation, a roller is provided at one end of the stop rod 9, and a roller sleeve 20 is sleeved on the outer surface of the roller to abut against the workpiece 7. Generally speaking, the roller adopts a bearing, the inner ring of the bearing is connected to one end of the stop rod 9, and the outer ring is connected to the inner hole wall of the roller sleeve 20. When the workpiece 7 rotates, since one end of the workpiece 7 abuts against the roller sleeve 20, the roller sleeve 20 and the workpiece 7 can keep rotating synchronously.

[0039] As mentioned above, the position of the pressing wheel 11 of the present invention is driven and moved by the second driving mechanism. Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, the second driving mechanism is arranged on a lower guide rail bracket 21 on the base 1, and a lower guide rail 22 is arranged on the lower guide rail bracket 21, and the lower guide rail 22 is arranged perpendicular to the first main shaft 4, and an upper guide rail bracket 23 is slidably provided on the lower guide rail 22 through a slider, and a first cylinder 24 is also arranged on the lower guide rail bracket 21, and the piston rod of the first cylinder 24 is connected with the lower guide rail bracket 21 through a lower push plate 25, and an upper guide rail arranged along the up and down direction is arranged on the upper guide rail bracket 23, and a second cylinder 26 is also arranged on the upper guide rail bracket 23, and the piston of the second cylinder 26 is arranged along the up and down direction and connected with a drag plate 28 through an upper push plate 27, and the drag plate 28 is slidably provided on the upper guide rail through a slider, and a pressure wheel block 29 is fixed on the drag plate 28, and the drag plate 28 is driven by the second cylinder 26 to move up and down, and the upper end of the pressure wheel seat 10 is connected with the pressure wheel block 29, and the lower end is provided with a pressure wheel 11. The first cylinder 24 drives the pressing wheel 11 to reciprocate along the lower guide rail 22 , and the second cylinder 26 drives the pressing wheel 11 to reciprocate up and down, thereby adjusting the position of the pressing wheel 11 .

[0040] In addition, the first cylinder 24 and the second cylinder 26 of the present invention can be replaced by a screw motor mechanism.

[0041] The structures of the first main shaft 4 and the second main shaft of the utility model are described in detail below. The first main shaft 4 and the second main shaft adopt the same structure, such as Fig. 9 As shown, it includes an axle body 30, a first axle body 31 and a second axle body 32 at the rear end of the axle body 30, and a third axle body 33 and a fourth axle body 34 are sequentially arranged at the front end of the axle body 30, the diameter of the axle body 30 is greater than the diameter of the first axle body 31> the diameter of the second axle body 32, a first step surface 35 is formed between the axle body 30 and the first axle body 31, a second step surface 36 is formed between the first axle body 31 and the second axle body 32, the diameter of the axle body 30 is less than the third axle body 33, and a third step surface 37 is formed between the axle body 30 and the third axle body 33.

[0042] The first main shaft 4 and the second main shaft of the utility model are rotatably connected to the first guide wheel seat 2 and the second guide wheel seat 3 through the front bearing 44 and the rear bearing 38 respectively, and have strong rigidity.

[0043] like Figure 3 As shown, the first shaft body 31 is sequentially provided with a rear bearing 38, a rear bearing retaining ring 39, a rear locking ring 40 and a rear limiting member 41 from front to rear, the rear end faces of the first guide wheel seat 3 and the second guide wheel seat 4 are fixed with a rear end cover 42 by screws, the rear bearing retaining ring 39 passes through the rear end cover 42 and abuts against the rear bearing 38, a plurality of threaded holes are evenly distributed circumferentially on the rear locking ring 40, the screws are screwed into the threaded holes and abut against the rear bearing retaining ring 39, a sealing ring 43 is provided between the rear bearing retaining ring 39 and the rear end cover 42, and the rear limiting member 41 is closely abutted against the rear end of the rear locking ring 40, so that the rear bearing 38, the rear bearing retaining ring 39 and the rear locking ring 40 are sequentially abutted and limited between the first step surface 35 and the rear limiting member 41.

[0044] The front end of the shaft body 30 is provided with a front bearing 44, a front bearing retaining ring 45, a front locking ring 46 and a front limit piece 46 in sequence from front to rear. The front locking ring 46 has a plurality of threaded holes evenly distributed circumferentially. The screws are screwed into the threaded holes and abut against the front bearing retaining ring 45. The front limit piece 46 is tightly abutted against the rear end of the front locking ring 46. In this way, the front bearing 44, the front bearing retaining ring 45 and the front locking ring 46 are successively abutted and limited between the third step surface 37 and the front limit piece 47.

[0045] It should be noted that the rear limiter 41 and the front limiter 47 are wire retaining rings. In addition, the utility model can fine-tune the axial preload accuracy of the first spindle 4 and the second spindle through the structure of the rear locking ring 40 and the front locking ring 46.

[0046] The first driven wheel 12 and the second driven wheel 13 are respectively arranged on the second shaft body 32 on the first main shaft 4 and the second main shaft.

[0047] In addition, the fourth shaft body 34 of the utility model is a frustum of a cone, and a conical hole matching the frustum of a cone is provided in the first guide wheel 5 or the second guide wheel 6. The first guide wheel 5 or the second guide wheel 6 is mounted on the fourth shaft body 34 and fixedly connected to the end face of the fourth shaft body 34 by a gasket 48 and a screw.

[0048] The base 1 of the utility model is slidably arranged on the slide table 48, so as to facilitate the overall adjustment of the position of the utility model on a common cylindrical grinder.

[0049] The above embodiment is only one of the preferred embodiments of the present utility model, and is not intended to limit the scope of implementation of the present utility model. Therefore, any equivalent changes made based on the shape, structure, and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A pressure wheel device without a center hole, characterized in that: The invention comprises a first guide wheel seat (2) and a second guide wheel seat (3) which are arranged side by side. A first spindle (4) is rotatably arranged in the first guide wheel seat (2), and a second spindle is rotatably arranged in the second guide wheel seat (3). The first spindle (4) and the second spindle are arranged in parallel. One end of the first spindle (4) and the second spindle are driven to rotate synchronously by a first driving mechanism, and the other end is respectively provided with a first guide wheel (5) and a second guide wheel (6). A placement position for a workpiece (7) is formed between the first guide wheel (5) and the second guide wheel (6). A workpiece adjustment frame (8) is arranged on the first guide wheel seat (2) and the second guide wheel seat (3). A limiting rod (9) is arranged on the workpiece adjustment frame (8) and abuts against one end of the workpiece (7). A second driving mechanism is arranged on one side of the first guide wheel seat (2) or the second guide wheel seat (3). The second driving mechanism is connected to a pressure wheel seat (10). A pressure wheel (11) which can be pressed on the workpiece (7) is arranged on the pressure wheel seat (10).

2. A center hole-free pressing wheel device according to claim 1, characterized in that: A support rod (49) is also provided on the base, and the support rod (49) is located between the first guide wheel seat (2) and the second guide wheel seat (3).

3. A center hole-free pressing wheel device according to claim 1 or 2, characterized in that: The first driving mechanism comprises a first driven wheel (12), a second driven wheel (13), and a driving motor (14); a driving wheel is arranged on the driving motor (14); the driving wheel, the first driven wheel (12), and the second driven wheel (13) are connected by a synchronous belt (15); the driving motor (14) drives the driving wheel to rotate, thereby driving the first driven wheel (12) and the second driven wheel (13) to rotate through the synchronous belt (15).

4. A center hole-free pressing wheel device according to claim 1 or 2, characterized in that: The workpiece adjustment frame (8) comprises a workpiece adjustment plate (16), both ends of which are provided with strip holes (17), the long axis of the strip hole (17) being arranged perpendicular to the first main axis (4), the workpiece adjustment plate (16) being screwed onto the first guide wheel seat (2) and the second guide wheel seat (3) by means of screws passing through the strip holes (17), and the workpiece adjustment plate (16) can be adjusted in position along the long axis direction, a workpiece adjustment block (18) is arranged on the workpiece adjustment plate (16), a through hole matching the shape of the limit rod (9) is arranged on the workpiece adjustment block (18), threaded holes (19) communicating with the through holes are arranged on the workpiece adjustment plate (16) and the workpiece adjustment block (18), the screws are screwed into the threaded holes (19) and the inner ends of the screws abut against the limit rod (9) to lock the limit rod (9).

5. A center hole-free pressing wheel device according to claim 4, characterized in that: A roller is provided at one end of the limiting rod (9), and a roller sleeve (20) is sleeved outside the roller and abuts against the workpiece (7).

6. A center hole-free pressing wheel device according to claim 1 or 2, characterized in that: The second driving mechanism comprises a lower guide rail bracket (21), on which a lower guide rail (22) and a first cylinder (24) are arranged, the lower guide rail (22) is arranged perpendicular to the first main shaft (4), the upper guide rail bracket (23) is slidably connected to the lower guide rail (22), the piston rod of the first cylinder (24) is connected to the upper guide rail bracket (23), the upper guide rail and the second cylinder (26) arranged in the up-down direction are arranged on the upper guide rail bracket (23), the piston of the second cylinder (26) is arranged in the up-down direction, the drag plate (28) is slidably arranged on the upper guide rail, the pressure wheel block (29) is fixedly arranged on the drag plate (28), the drag plate (28) is driven by the second cylinder (26) to move up and down, the upper end of the pressure wheel seat (10) is connected to the pressure wheel block (29), and the lower end is provided with a pressure wheel (11).

7. A center hole-free pressing wheel device according to claim 1 or 2, characterized in that: The first main shaft (4) and the second main shaft comprise a shaft body (30), a first shaft body (31) and a second shaft body (32) at the rear end of the shaft body (30), and a third shaft body (33) and a fourth shaft body (34) are sequentially arranged at the front end of the shaft body (30); the diameter of the shaft body (30) is greater than the diameter of the first shaft body (31) and the diameter of the second shaft body (32); a first step surface (35) is formed between the shaft body (30) and the first shaft body (31); a second step surface (36) is formed between the first shaft body (31) and the second shaft body (32); the diameter of the shaft body (30) is less than the third shaft body (33); and a third step surface (37) is formed between the shaft body (30) and the third shaft body (33).

8. A center hole-free pressing wheel device according to claim 7, characterized in that: The first shaft body (31) is provided with a rear bearing (38), a rear bearing retaining ring (39), a rear locking ring (40) and a rear limit piece (41) in sequence from front to rear; the rear end surfaces of the first guide wheel seat (2) and the second guide wheel seat (3) are provided with a rear end cover; the rear bearing retaining ring (39) passes through the rear end cover and abuts against the rear bearing (38); a plurality of threaded holes are evenly distributed circumferentially on the rear locking ring (40); screws are screwed into the threaded holes and abut against the rear bearing retaining ring (39); a sealing ring (43) is provided between the rear bearing retaining ring (39) and the rear end cover; and the rear limit piece (41) is closely abutted against the rear end of the rear locking ring (40).

9. The pressure wheel device without a center hole according to claim 7, characterized in that: The front end of the shaft body (30) is provided with a front bearing (44), a front bearing retaining ring (45), a front locking ring (46) and a front stopper (47) in sequence from front to rear. The front locking ring (46) is provided with a plurality of threaded holes evenly distributed circumferentially. Screws are screwed into the threaded holes and abut against the front bearing retaining ring (45). The front stopper (47) abuts against the rear end of the front locking ring (46).

10. The pressure wheel device without a center hole according to claim 7, characterized in that: The fourth shaft body (34) is a truncated cone, and a conical hole matching the truncated cone is arranged in the first guide wheel (5) or the second guide wheel (6). The first guide wheel (5) or the second guide wheel (6) is mounted on the fourth shaft body (34) and fixedly connected to the end face of the fourth shaft body (34) by means of a gasket (48) and a screw.

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