Precise gear transmission disc type multi-station automatic exchange milling head library structure

Abstract

The invention provides a precise gear transmission disc type multi-station automatic exchange milling head library structure, and relates to the technical field of composite gantry machine tools, the precise gear transmission disc type multi-station automatic exchange milling head library structure comprises a milling head library chassis seat and a milling head driving group, the upper end of the milling head library chassis seat is provided with a plurality of chassis seat side panels, and the upper ends of the chassis seat side panels are integrally provided with a station rotating table; a bearing limiting table is integrally arranged at the upper end of the station rotating table, and a milling head rotating table is arranged at the upper end of the bearing limiting table; a servo motor is started to drive conversion driving teeth at the upper end to be meshed with an exchange rotating fluted disc to rotate, so that the exchange rotating fluted disc drives a milling head rotating table at the upper end to rotate, a milling head driving set at the upper end can reach an accurate station through accurate driving of the servo motor, and an external driving source is connected; the milling head is replaced in the mode, compared with the prior art, the occupied space of the whole machine tool is smaller, replacement is more convenient, abrasion of a replacement structure is reduced, and the maintenance period is longer.

Description

Technical Field

[0001] The present invention relates to the technical field of compound gantry machine tools, and particularly to a precision gear-driven disc-type multi-station automatic exchange milling head library structure. Background Art

[0002] In the field of compound gantry machine tools, it is becoming increasingly common to configure a gantry with multiple accessory milling heads, and the demand for a multi-station automatic exchange accessory milling head library is also increasing. For example, for the gantry machine tool protection device and gantry machine tool with the application number CN202211064718.8, traditional accessory milling head libraries mostly adopt a linear reciprocating pushing method or a fixed placement method. In the case of exchanging multiple accessory milling heads, the former not only requires a long movement stroke but also needs to increase the Y-axis stroke of the gantry machine tool, resulting in a relatively large change in the overall structure of the machine tool; the latter generally needs to be placed at one end or both ends of the workbench to expand the number of head library positions, but this method occupies a large stroke in the workbench direction and affects the normal machining range of the machine tool. Summary of the Invention

[0003] Aiming at the deficiencies of the prior art, the present invention provides a precision gear-driven disc-type multi-station automatic exchange milling head library structure, which solves the problems raised in the background art.

[0004] To achieve the above objectives, the present invention is realized through the following technical solutions: A precision gear-driven disc-type multi-station automatic exchange milling head library structure, including a milling head library chassis seat and a milling head drive group. A plurality of chassis seat side panels are provided at the upper end of the milling head library chassis seat. A station rotating table is integrally provided at the upper end of the chassis seat side panel. A bearing limit table is integrally provided at the upper end of the station rotating table. A milling head rotating table is provided at the upper end of the bearing limit table; The milling head drive group is fixedly installed on the upper surface of the milling head rotating table.

[0005] Preferably, a panel stabilizing steel beam is provided at the interval between the chassis seat side panels. A rotating bearing supporting table is integrally provided inside the bearing limit table. A rotating table bearing seat is provided between the rotating bearing supporting table and the milling head rotating table.

[0006] Preferably, an exchange rotating gear disk is integrally provided at the lower end of the milling head rotating table. A servo motor installation table is integrally provided inside the station rotating table; One side of the lower surface of the servo motor installation table is fixedly installed with a servo motor hoisting plate. A servo motor is fixedly installed at the lower end of the servo motor hoisting plate. A conversion drive gear is coaxially and fixedly installed on the output shaft of the servo motor. A motor installation groove is provided on one of the chassis seat side panels and at the rear end of the servo motor.

[0007] Preferably, the conversion drive gears are meshed with each other.

[0008] Preferably, the milling head drive group includes: a milling head frame bottom plate, a milling head frame triangular iron, a milling head frame hoop, a milling head frame top plate, a seal sleeve base groove, a seal sleeve base, a milling head rotating bearing seat, an inner rotating box, a lower extension shaft sleeve, a drive shaft connection box group, and a mounting fixing ring; At the four corners of the upper surface of the milling head frame bottom plate, milling head frame triangular irons are fixedly installed. Between the milling head frame triangular irons, a number of milling head frame hoops are arranged. At the upper end of the milling head frame triangular irons, a milling head frame top plate is fixedly installed. In the middle of the milling head frame top plate, a seal sleeve base groove is provided; An installation fixing ring is integrally provided on the inner wall of the seal sleeve base groove. The seal sleeve base is fixedly installed on the installation fixing ring. A milling head rotating bearing seat is provided at the upper end of the seal sleeve base; The milling head frame top plate is fixedly installed with an inner rotating box at the lower end. The inner rotating box is integrally provided with a lower extension shaft sleeve at the lower end. The lower extension shaft sleeve is fixedly installed with a drive shaft connection box group at the lower end.

[0009] Preferably, a milling cutter clamping head is rotatably installed at the upper end of the milling head rotating bearing seat. A rotating milling cutter is arranged in the middle of the milling cutter clamping head.

[0010] Preferably, a milling head transmission shaft is coaxially and fixedly installed at the lower end of the milling cutter clamping head. A variable diameter shaft is coaxially and fixedly connected to the lower end of the milling head transmission shaft.

[0011] Preferably, the drive shaft connection box group includes: a connection box main cylinder, a connection box top cylinder, a drive connection groove, a drive connection sleeve, a drive connection spline groove, a sleeve limit ring, a sliding inner spline sleeve, a top spring platform, and a transverse fixed shaft; The connection box main cylinder is integrally provided with a connection box top cylinder at the upper end. A drive connection groove is provided at the front end of the connection box main cylinder. A drive connection sleeve is rotatably arranged in the drive connection groove. A drive connection spline groove is provided at the front end of the drive connection sleeve; The inner wall of the front end of the connection box main cylinder is integrally provided with a sleeve limit ring. A sliding inner spline sleeve is integrally provided at the rear end of the drive connection sleeve and inside the sleeve limit ring. A top spring platform is integrally provided in the middle of the inner end of the sliding inner spline sleeve. A transverse fixed shaft is rotatably installed at the bottom of the connection box main cylinder.

[0012] Preferably, a first transmission bevel gear is integrally provided coaxially in the middle of the transverse fixed shaft. A sliding outer spline sleeve is integrally provided at the outer end of the transverse fixed shaft. A floating top spring is arranged inside the sliding outer spline sleeve.

[0013] Preferably, a top shaft limiting disc is integrally provided on the inner wall of the top cylinder of the connection box. A driving top shaft is rotatably installed in the middle of the top shaft limiting disc. A second driving bevel gear is integrally provided coaxially at the lower end of the driving top shaft; A first driving bevel gear is meshed between the first driving bevel gear and the second driving bevel gear; The upper end of the driving top shaft is integrally provided coaxially with a variable diameter shaft.

[0014] The present invention provides a precision gear transmission disc-type multi-station automatic exchange milling head library structure. It has the following beneficial effects: (1) In the present invention, by starting the servo motor to drive the conversion drive teeth at the upper end to engage and rotate the exchange rotating tooth disc, the exchange rotating tooth disc drives the milling head rotating table at the upper end to rotate. Through the precise drive of the servo motor, the milling head drive group at the upper end can reach the accurate working position and connect to an external drive source. By replacing the milling head in the above manner, it occupies less space in the overall machine tool compared with the prior art, is more convenient to replace, reduces the wear of the replacement structure, and has a longer maintenance cycle; (2) In the present invention, by inserting the drive source into the drive connection spline groove and through the sliding sleeve between the sliding inner spline sleeve and the sliding outer spline sleeve at the rear end, it can protect the external drive shaft from being damaged when the connection fails. It is reset by the floating top spring at the rear end, and then the first driving bevel gear meshes with the second driving bevel gear at the upper end to rotate, so as to drive the driving top shaft at the upper end to rotate; (3) In the present invention, the driving top shaft drives the variable diameter shaft at the upper end, and then drives the milling head drive shaft to rotate, so as to drive upward and drive the milling cutter clamping head to rotate, so that the rotating milling cutter at the upper end can rotate and work. The oil stain can be prevented from entering the inside of the milling head rotating bearing seat through the sealing sleeve base at the lower end, affecting the lubricated rotation. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a schematic side view structure of the present invention; Figure 3 For the present invention Figure 2 The sectional structure schematic diagram of the a-a line in; Figure 4 It is a schematic diagram of the structure of the milling head drive group in the present invention; Figure 5 It is a schematic side view structure of the milling head drive group in the present invention; Figure 6 For the present invention Figure 5 The sectional structure schematic diagram of the b-b line in; Figure 7 It is a schematic diagram of the structure of the drive shaft connection box group in the present invention; Figure 8 It is a schematic side view structure diagram of the drive shaft connection box group in the present invention; Figure 9 For the present invention Figure 8 It is a schematic cross-sectional structure diagram of the c-c line in the present invention.

[0016] Wherein, 1. Milling head library chassis base; 2. Chassis base side panel; 3. Station rotating table; 4. Bearing limiting table; 5. Milling head rotating table; 6. Milling head drive group; 601. Milling head frame bottom plate; 602. Milling head frame triangular iron; 603. Milling head frame hoop; 604. Milling head frame top plate; 605. Sealing sleeve base groove; 606. Sealing sleeve base; 607. Milling head rotating bearing seat; 608. Milling cutter clamping head; 609. Rotating milling cutter; 610. Inner rotating box; 611. Lower extension shaft sleeve; 612. Drive shaft connection box group; 6121. Connection box main cylinder; 6122. Connection box top cylinder; 6123. Top shaft limiting disc; 6124. Transmission top shaft; 6125. Drive connection groove; 6126. Drive connection sleeve; 6127. Drive connection spline groove; 6128. Sleeve limiting ring; 6129. Sliding inner spline sleeve; 61210. Top spring platform; 61211. Sliding outer spline sleeve; 61212. Transverse fixed shaft; 61213. First transmission bevel gear; 61214. Floating top spring; 61215. Second transmission bevel gear; 613. Installation fixing ring; 614. Milling head transmission shaft; 615. Reducing shaft; 7. Panel stabilizing steel frame; 8. Servo motor installation platform; 9. Rotating bearing supporting table; 10. Servo motor hoisting plate; 11. Servo motor; 12. Conversion drive gear; 13. Motor installation groove; 14. Exchange rotating gear disc; 15. Rotating table bearing seat. Specific embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] Such as Figures 1 to 3As shown in the figure, an embodiment of the present invention provides a precision gear-driven disc-type multi-station automatic exchange milling head library structure, including a milling head library chassis base 1 and a milling head drive group 6. A plurality of chassis base side panels 2 are arranged at the upper end of the milling head library chassis base 1. A station rotating table 3 is integrally arranged at the upper end of the chassis base side panel 2. A bearing limit table 4 is integrally arranged at the upper end of the station rotating table 3. A milling head rotating table 5 is arranged at the upper end of the bearing limit table 4. The milling head drive group 6 is fixedly installed on the upper surface of the milling head rotating table 5. A panel stabilizing steel frame 7 is arranged at the interval between the chassis base side panels 2. A rotating bearing supporting table 9 is integrally arranged inside the bearing limit table 4. A rotating table bearing seat 15 is arranged between the rotating bearing supporting table 9 and the milling head rotating table 5. An exchange rotating gear disc 14 is integrally arranged at the lower end of the milling head rotating table 5. A servo motor installation table 8 is integrally arranged inside the station rotating table 3. A servo motor hoisting plate 10 is fixedly installed on one side of the lower surface of the servo motor installation table 8. A servo motor 11 is fixedly installed at the lower end of the servo motor hoisting plate 10. A conversion drive gear 12 is coaxially fixedly installed on the output shaft of the servo motor 11. A motor installation groove 13 is opened on one of the chassis base side panels 2 and at the rear end of the servo motor 11. The conversion drive gear 12 is meshed and connected with the conversion drive gear 12.

[0019] In the above technical solution, by starting the servo motor 11 to drive the upper conversion drive gear 12 to mesh and rotate the exchange rotating gear disc 14, thereby the exchange rotating gear disc 14 drives the upper milling head rotating table 5 to rotate. Through the precise drive of the servo motor 11, the upper milling head drive group 6 can reach the accurate station and connect to an external drive source. By replacing the milling head in the above manner, first, it occupies less space in the overall machine tool compared with the prior art, the replacement is more convenient, the wear of the replacement structure is reduced, and the maintenance cycle is longer.

[0020] Such as Figure 1 、 Figures 4 to 6As shown in the figure, the milling head drive group 6 includes: a milling head frame bottom plate 601, a milling head frame triangular iron 602, a milling head frame hoop 603, a milling head frame top plate 604, a seal sleeve base groove 605, a seal sleeve base 606, a milling head rotating bearing seat 607, an inner rotating box 610, a lower extension shaft sleeve 611, a drive shaft connection box group 612, and a mounting and fixing ring 613. At the four corners of the upper surface of the milling head frame bottom plate 601, milling head frame triangular irons 602 are fixedly installed. Between the milling head frame triangular irons 602, several milling head frame hoops 603 are provided. At the upper end of the milling head frame triangular iron 602, a milling head frame top plate 604 is fixedly installed. In the middle of the milling head frame top plate 604, a seal sleeve base groove 605 is formed. On the inner wall of the seal sleeve base groove 605, a mounting and fixing ring 613 is integrally provided. On the mounting and fixing ring 613, a seal sleeve base 606 is fixedly installed. At the upper end of the seal sleeve base 606, a milling head rotating bearing seat 607 is provided. At the lower end of the milling head frame top plate 604, an inner rotating box 610 is fixedly installed. At the lower end of the inner rotating box 610, a lower extension shaft sleeve 611 is integrally provided. At the lower end of the lower extension shaft sleeve 611, a drive shaft connection box group 612 is fixedly installed. At the upper end of the milling head rotating bearing seat 607, a milling cutter clamping head 608 is rotatably installed. In the middle of the milling cutter clamping head 608, a rotating milling cutter 609 is provided. At the lower end of the milling cutter clamping head 608, a milling head transmission shaft 614 is coaxially fixedly installed. At the lower end of the milling head transmission shaft 614, a stepped shaft 615 is coaxially fixedly connected.

[0021] In the above technical solution, it is transmitted to the upper stepped shaft 615 through the transmission top shaft 6124 and then transmitted to the milling head transmission shaft 614 to rotate, so that it can be transmitted upward to drive the milling cutter clamping head 608 to rotate, and then the upper rotating milling cutter 609 can be driven to rotate and work. Through the lower seal sleeve base 606, it can prevent oil and grease from entering the inside of the milling head rotating bearing seat 607 and affecting the lubricated rotation.

[0022] Such as Figure 4 、 Figures 7 to 9As shown in the figure, the drive shaft connection box group 612 includes: a connection box main cylinder 6121, a connection box top cylinder 6122, a drive connection groove 6125, a drive connection sleeve 6126, a drive connection spline groove 6127, a sleeve limit ring 6128, a sliding internal spline sleeve 6129, a top spring platform 61210, and a transverse fixed shaft 61212; the upper end of the connection box main cylinder 6121 is integrally provided with a connection box top cylinder 6122, the front end of the connection box main cylinder 6121 is provided with a drive connection groove 6125, a drive connection sleeve 6126 is rotatably arranged in the drive connection groove 6125, and a drive connection spline groove 6127 is provided at the front end of the drive connection sleeve 6126; the front end inner wall of the connection box main cylinder 6121 is integrally provided with a sleeve limit ring 6128, and a sliding internal spline sleeve 6129 is integrally provided at the rear end of the drive connection sleeve 6126 and inside the sleeve limit ring 6128, a top spring platform 61210 is integrally provided in the middle of the inner end of the sliding internal spline sleeve 6129, a transverse fixed shaft 61212 is rotatably installed at the bottom of the connection box main cylinder 6121, a first transmission bevel gear 61213 is integrally provided coaxially in the middle of the transverse fixed shaft 61212, a sliding external spline sleeve 61211 is integrally provided at the outer end of the transverse fixed shaft 61212, a floating top spring 61214 is arranged inside the sliding external spline sleeve 61211, a top shaft limit disc 6123 is integrally provided on the inner wall of the connection box top cylinder 6122, a transmission top shaft 6124 is rotatably installed in the middle of the top shaft limit disc 6123, and a second transmission bevel gear 61215 is integrally provided coaxially at the lower end of the transmission top shaft 6124; the first transmission bevel gear 61213 and the second transmission bevel gear 61215 are meshed; the upper end of the transmission top shaft 6124 is integrally provided coaxially with the variable diameter shaft 615.

[0023] In the above technical solution, by inserting the drive source into the drive connection spline groove 6127 and through the sliding sleeve between the rear sliding internal spline sleeve 6129 and the sliding external spline sleeve 61211, it can be protected from being damaged when the external drive shaft connection fails. It is reset by the rear floating top spring 61214, and then the upper transmission top shaft 6124 is driven to rotate by the meshing of the first transmission bevel gear 61213 with the second transmission bevel gear 61215 at the upper end.

[0024] Working principle: In the present invention, by starting the servo motor 11 to drive the upper conversion drive gear 12 to mesh with and rotate the exchange rotating gear disc 14, the exchange rotating gear disc 14 drives the upper milling head rotating table 5 to rotate. Through the precise drive of the servo motor 11, the upper milling head drive group 6 can reach the accurate working position and connect with an external drive source. By the above method of replacing the milling head, it occupies less space in the overall machine tool compared with the prior art, is more convenient to replace, reduces the wear of the replacement structure, and has a longer maintenance cycle. Among them, by inserting the driving source into the driving connection spline groove 6127, and through the sliding sleeve between the sliding internal spline sleeve 6129 and the sliding external spline sleeve 61211 at the rear end, it can protect the external drive shaft from being damaged when the connection fails. It is reset by the floating top spring 61214 at the rear end, and then the first driving bevel gear 61213 meshes with the second driving bevel gear 61215 at the upper end to rotate, so as to drive the driving top shaft 6124 at the upper end to rotate; Among them, it is transmitted to the variable-diameter shaft 615 at the upper end through the driving top shaft 6124, and transmitted to the milling head drive shaft 614 to rotate, so as to be transmitted upward, drive the milling cutter clamping head 608 to rotate, and thus enable the rotary milling cutter 609 at the upper end to rotate and work. The sealing sleeve base 606 at the lower end can prevent oil and grease from entering the inside of the milling head rotating bearing seat 607, affecting the lubricated rotation.

[0025] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made on the basis of the above description. It is impossible to list all the implementation manners here. Any obvious changes or variations derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A precision gear-driven disc-type multi-station automatic exchange milling head magazine structure, comprising a milling head magazine chassis (1) and a milling head drive group (6), characterized in that: A plurality of chassis seat side panels (2) are arranged at the upper end of the milling head storage chassis seat (1); a workstation rotating platform (3) is integrally arranged at the upper end of the chassis seat side panels (2); a bearing limit platform (4) is integrally arranged at the upper end of the workstation rotating platform (3); and a milling head rotating platform (5) is arranged at the upper end of the bearing limit platform (4); The milling head driving group (6) is fixedly mounted on the upper end surface of the milling head rotating platform (5).

2. According to claim 1, a precision gear transmission disc type multi-station automatic exchange milling head library structure is characterized in that: Panel stabilizing steel frames (7) are provided at intervals between the side panels (2) of the chassis seat, a rotating bearing support platform (9) is integrally provided on the inner side of the bearing limit platform (4), and a rotating platform bearing seat (15) is provided between the rotating bearing support platform (9) and the milling head rotating platform (5).

3. According to claim 2, a precision gear transmission disc type multi-station automatic exchange milling head library structure is characterized in that: The lower end of the milling head rotating platform (5) is integrally provided with an exchange rotating gear disc (14), and the inner side of the workstation rotating platform (3) is integrally provided with a servo motor mounting platform (8); A servo motor hanging plate (10) is fixedly mounted on one side of the lower end surface of the servo motor mounting platform (8), a servo motor (11) is fixedly mounted on the lower end of the servo motor hanging plate (10), a conversion drive gear (12) is coaxially fixedly mounted on the output shaft of the servo motor (11), and a motor mounting groove (13) is provided on one of the chassis seat side panels (2) and located at the rear end of the servo motor (11).

4. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 3 is characterized in that: The conversion drive teeth (12) are meshingly connected with the conversion drive teeth (12).

5. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 4 is characterized in that: The milling head drive group (6) comprises: a milling head frame bottom plate (601), a milling head frame triangle iron (602), a milling head frame hoop (603), a milling head frame top plate (604), a sealing sleeve base groove (605), a sealing sleeve base (606), a milling head rotating bearing seat (607), an inner rotating box (610), a lower extension sleeve (611), a drive shaft connection box group (612), and an installation fixing ring (613); Milling head frame triangles (602) are fixedly mounted at the four corners of the upper surface of the milling head frame bottom plate (601), a plurality of milling head frame hoops (603) are arranged between the milling head frame triangles (602), a milling head frame top plate (604) is fixedly mounted on the upper end of the milling head frame triangles (602), and a sealing sleeve base groove (605) is provided in the middle of the milling head frame top plate (604); An installation fixing ring (613) is integrally provided on the inner wall of the sealing sleeve base groove (605), a sealing sleeve base (606) is fixedly installed on the installation fixing ring (613), and a milling head rotating bearing seat (607) is provided at the upper end of the sealing sleeve base (606); An inner rotating box (610) is fixedly mounted on the lower end of the milling head frame top plate (604), a lower extending shaft sleeve (611) is integrally provided on the lower end of the inner rotating box (610), and a driving shaft connecting box assembly (612) is fixedly mounted on the lower end of the lower extending shaft sleeve (611).

6. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 5 is characterized in that: A milling cutter clamping head (608) is rotatably mounted on the upper end of the milling head rotating bearing seat (607), and a rotating milling cutter (609) is arranged in the middle of the milling cutter clamping head (608).

7. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 6 is characterized in that: A milling head transmission shaft (614) is coaxially fixedly mounted on the lower end of the milling cutter clamping head (608), and a reducing shaft (615) is coaxially fixedly connected to the lower end of the milling head transmission shaft (614).

8. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 7 is characterized in that: The drive shaft connection box assembly (612) comprises: a connection box main cylinder (6121), a connection box top cylinder (6122), a drive connection groove (6125), a drive connection sleeve (6126), a drive connection spline groove (6127), a sleeve limiting ring (6128), a sliding inner spline sleeve (6129), a top spring platform (61210), and a transverse fixed shaft (61212); The upper end of the connection box main cylinder (6121) is integrally provided with a connection box top cylinder (6122); the front end of the connection box main cylinder (6121) is provided with a drive connection groove (6125); a drive connection sleeve (6126) is rotatably provided in the drive connection groove (6125); and a drive connection spline groove (6127) is provided at the front end of the drive connection sleeve (6126); A sleeve limiting ring (6128) is integrally provided at the front end of the inner wall of the connecting box main cylinder (6121), a sliding internal spline sleeve (6129) is integrally provided at the rear end of the driving connecting sleeve (6126) and located inside the sleeve limiting ring (6128), a top spring platform (61210) is integrally provided in the middle of the inner end of the sliding internal spline sleeve (6129), and a transverse fixed shaft (61212) is rotatably installed at the bottom of the connecting box main cylinder (6121).

9. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 8 is characterized in that: The middle of the transverse fixed shaft (61212) is coaxially and integrally provided with a first transmission bevel gear (61213), the outer end of the transverse fixed shaft (61212) is integrally provided with a sliding external spline sleeve (61211), and a floating top spring (61214) is provided inside the sliding external spline sleeve (61211).

10. The precision gear transmission disc type multi-station automatic exchange milling head library structure according to claim 9 is characterized in that: A top shaft limiting plate (6123) is integrally provided on the inner wall of the top cylinder (6122) of the connection box, a transmission top shaft (6124) is rotatably mounted in the middle of the top shaft limiting plate (6123), and a second transmission bevel gear (61215) is coaxially and integrally provided on the lower end of the transmission top shaft (6124); The first transmission bevel gear (61213) and the second transmission bevel gear (61215) are meshed with each other; The upper end of the transmission top shaft (6124) is coaxially and integrally arranged with the reducing shaft (615).

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