CN217727000U

CN217727000U - Milling machine for cold-rubbing forming of spline

Info

Publication number: CN217727000U
Application number: CN202222066401.XU
Authority: CN
Inventors: 范啸峰; 余淼良; 孙娜萍
Original assignee: Hangzhou Lin'an Xiongfeng Machinery Co ltd
Current assignee: Hangzhou Lin'an Xiongfeng Machinery Co ltd
Priority date: 2022-08-05
Filing date: 2022-08-05
Publication date: 2022-11-04
Anticipated expiration: 2032-08-05

Abstract

The application discloses cold forming milling machine of rubbing with hands of spline, including the lathe that is used for rubbing with the hands the spline, the lathe is equipped with the transport mechanism who is used for conveying the work piece and is close to the lathe, the lathe is equipped with the moving mechanism who is used for controlling the work piece and removes to the lathe inside, the lathe be equipped with for the clamping mechanism of the different diameter work pieces of butt, clamping mechanism is including supporting cover one and supporting cover two, support cover one and supporting cover two and all offer the through-hole that is used for the work piece tip to stretch into, the slope of through-hole inner wall sets up, the one end that two through-hole internal diameters are minimum is located the one end that supports cover one and support cover two and keep away from each other, support cover one and support cover two and be connected with respectively and be used for driving and support cover one and support cover two and be close to or keep away from the drive assembly two and the drive assembly two of work piece both ends, the one end that transport mechanism was kept away from to the moving mechanism is connected with the unloading mechanism that is used for processing the work piece unloading of accomplishing. Use this application, carry out the centre gripping to the work piece of different diameters, it is more convenient to use.

Description

Milling machine for cold-rubbing forming of spline

Technical Field

The application relates to the field of machining equipment, in particular to a milling machine for cold-rubbing forming of splines.

Background

The spline connection has wide application in the mechanical manufacturing industry, and has the characteristics of high centering precision, good guiding performance, large bearing capacity, capability of transmitting larger torque and the like. The cold twist forming of the spline forms teeth through plastic deformation, does not generate cutting scraps, and is a chipless rolling and precise plastic forming processing technology.

The publication number is CN 111167982A's patent discloses a gear rolling machine for spline, which comprises a housin, be equipped with the gear rolling piece of symmetric distribution in the casing, be equipped with the driving source that the drive gear rolling piece removed on the casing, one side of casing is equipped with transmission device, one side of transmission device is equipped with sharp electric jar, sharp electric jar is equipped with the support clamping piece, transmit the work piece through transmission device, the support clamping piece presss from both sides tightly the work piece, it removes to support the clamping piece through sharp electric jar drive, the work piece stretches into the feed port and extends to between two gear rolling pieces, remove to opposite square through two gear rolling pieces of driving source drive, gear rolling is carried out to the work piece, form the spline, the support clamping piece removes, make the work piece behind the gear rolling shift out the casing, take off the work piece.

In view of the above-mentioned related art, the supporting and clamping member cannot clamp workpieces of different diameters, and the supporting and clamping member needs to be replaced when the diameter of the workpiece is changed, which is troublesome.

SUMMERY OF THE UTILITY MODEL

In order to clamp workpieces with different diameters conveniently, the milling machine for cold rolling forming of the spline is provided, and the milling machine is mainly realized through the following technical scheme.

Milling machine for forming cold-rubbing spline, including the lathe that is used for rubbing the spline, the lathe is equipped with the transmission device who is used for conveying the work piece and is close to the lathe, the lathe is equipped with the moving mechanism who is used for controlling the work piece and removes to the lathe inside, the lathe be equipped with for the clamping mechanism of the different diameter work piece of butt, clamping mechanism is including supporting cover one and supporting cover two, support cover one and support cover two and all offer the through-hole that is used for the work piece tip to stretch into, the through-hole inner wall slope sets up, the one end that two through-hole internal diameters are minimum is located the one end that support cover one and support cover two of one-to-one kept away from each other, support cover one and support cover two and be connected with respectively and be used for driving support cover one and support cover two and be close to or keep away from the drive assembly two at work piece both ends, the one end that transmission device was kept away from to the moving mechanism is connected with the unloading mechanism that is used for processing the work piece unloading of accomplishing.

According to the technical scheme, the workpiece is transmitted to the moving mechanism by the transmission mechanism, the workpiece is conveyed to the inside of the machine tool by the moving mechanism, the first supporting sleeve and the second supporting sleeve are respectively sleeved at two axial ends of the workpiece, the inner walls of the through holes of the first supporting sleeve and the second supporting sleeve are gradually inclined, the workpieces with different diameters can be sleeved in a certain range, two ends of the workpiece with the large diameter are respectively abutted to one end, with the larger inner diameter, of the through hole in the first supporting sleeve and the second supporting sleeve, two ends of the workpiece with the small diameter are respectively abutted to the position, with the smaller inner diameter, of the through hole in the first supporting sleeve and the second supporting sleeve, so that the workpieces with different diameters are abutted to each other.

Optionally, the transmission mechanism includes a frame, the frame is rotationally connected with two belt pulleys, the two belt pulleys are in transmission connection with the same belt, a side wall of the frame is fixedly connected with a motor, and an output shaft of the motor penetrates through the side wall of the frame and is coaxially and fixedly connected to the belt pulleys in one-to-one correspondence.

Through above-mentioned technical scheme, the motor passes through the belt pulley and drives belt transmission, and the belt conveys the work piece to moving mechanism.

Optionally, the moving mechanism comprises a support frame, the support frame is connected with a support seat in a sliding manner, the support frame is connected with a third air cylinder for driving the support seat to move in the horizontal direction, the support seat is connected with a support piece for placing a workpiece, and the support piece is connected with a lifting air cylinder for driving the support piece to move in the vertical direction.

Through the technical scheme, the third cylinder drives the supporting seat and the supporting piece to get in and out of the machine tool, the lifting cylinder adjusts the heights of the axes of the workpieces with different diameters through the supporting piece, so that the heights of the axes of the workpieces are consistent with the heights of the axes of the first supporting sleeve and the second supporting sleeve, and two ends of the workpieces are conveniently sleeved on the first supporting sleeve and the second supporting sleeve respectively.

Optionally, the lifting air cylinders are provided with two lifting air cylinders and are respectively a first lifting air cylinder and a second lifting air cylinder, the cylinder bodies of the first lifting air cylinder and the second lifting air cylinder are hinged to the supporting seat, the first lifting air cylinder is connected to one end, close to the rack, of the supporting seat, the second lifting air cylinder is connected to one end, far away from the rack, of the supporting seat, and output shafts of the first lifting air cylinder and the second lifting air cylinder are hinged to one side, close to the supporting seat, of the supporting piece.

Through above-mentioned technical scheme, the output shaft of lift cylinder one and lift cylinder two stretches out simultaneously and retracts and is used for adjusting the height of support piece, and the support piece slope makes lift cylinder one and lift cylinder two slope thereupon for work piece on the support piece rolls and carries out the unloading to unloading mechanism and collect.

Optionally, the support member is arcuately disposed to contact a surface of the workpiece.

Through above-mentioned technical scheme, the work piece all belongs to the cylinder, and the arc can make the work piece laminate in support piece better, reduces the possibility that the work piece dropped from support piece.

Optionally, the first driving assembly comprises a linear electric cylinder, the linear electric cylinder is fixedly connected to one side of the support frame, which is far away from the machine tool, a first air cylinder is fixedly connected to a sliding block of the linear electric cylinder, a first support column is fixedly connected to an output shaft of the first air cylinder, and a first support sleeve is rotatably connected to the first support column; the second driving assembly comprises a second air cylinder, the second air cylinder is fixedly connected to one side, far away from the support frame, of the machine tool, an output shaft of the second air cylinder penetrates through the side wall of the machine tool and is fixedly connected with a second support column, and the second support sleeve is rotatably connected to the second support column.

Through the technical scheme, the first cylinder drives the support sleeve to move towards the workpiece through the support column, so that the support sleeve is sleeved on the end part of the workpiece, the second cylinder drives the support sleeve to move through the second support column, the support sleeve is sleeved on the end part of the workpiece, the first support sleeve and the second support sleeve are sleeved on the workpiece simultaneously, the workpiece is supported, and meanwhile the working position of the workpiece can be limited.

Optionally, the blanking mechanism comprises a blanking plate and a collecting box, the blanking plate is fixedly connected to one side, far away from the rack, of the support frame, one side, contacting with the workpiece, of the blanking plate is arranged in an inclined mode, and the collecting box is connected to the lowest position of the inclined plane of the blanking plate.

Through the technical scheme, the workpieces sliding from the supporting piece continue to slide from the discharging plate and enter the collecting box for collection, and due to the inclined design of the discharging plate, the workpieces can slide downwards by means of self gravity, and meanwhile, the possibility that the workpieces are damaged due to falling and impacting at high altitude is reduced.

Optionally, the two side walls of the end, close to the support member, of the machine frame are fixedly connected with transition pieces, one side, far away from the machine frame, of each transition piece is close to the side wall of the support member, and one side, far away from the support member, of each transition piece is close to the belt.

Through above-mentioned technical scheme, there is certain interval between belt and the support piece, and the transition has effectively reduced the possibility that the work piece dropped from the in-process work piece that the belt removed to support piece.

In conclusion, the inclined surfaces of the through holes in the first support sleeve and the second support sleeve are convenient for sleeving workpieces with different diameters in a certain range; the lifting movement of the supporting piece is convenient for adjusting the height of the axis of the workpiece, so that the height of the axis of the workpiece is consistent with that of the axis of the supporting sleeve, and the workpiece is conveniently and accurately sleeved with the first supporting sleeve and the second supporting sleeve; the workpieces roll down from the supporting piece to the blanking plate, and the workpieces roll down from the inclined blanking plate by means of self gravity to enter the collecting box for collection.

Drawings

Fig. 1 is a schematic view of the overall structure of the present application.

Fig. 2 is a cross-sectional view of the present application.

Fig. 3 is an enlarged view at a in fig. 2.

Fig. 4 is a sectional view showing the connection between the support member and the support seat according to the present invention.

Fig. 5 is an enlarged view at C in fig. 5.

Fig. 6 is an enlarged view at B in fig. 2.

Description of the reference numerals:

1. a machine tool; 2. a transport mechanism; 3. a moving mechanism; 4. a clamping mechanism; 5. a first support sleeve; 6. a second support sleeve; 7. a through hole; 8. a first driving component; 9. a second driving component; 10. a blanking mechanism; 11. a frame; 12. a belt pulley; 13. a belt; 14. a motor; 15. a support frame; 16. a supporting seat; 17. a third air cylinder; 18. a support member; 19. a lifting cylinder; 20. a first lifting cylinder; 21. a second lifting cylinder; 22. a linear electric cylinder; 23. a first cylinder; 24. a first supporting column; 25. a second air cylinder; 26. a second supporting column; 27. a blanking plate; 28. a collection box; 29. a transition piece; 31. A housing; 32. a gear rubbing piece; 33. a toothed rubbing plate; 34. a cylinder IV; 35. a chute; 36. a slider; 37. and a concave hole.

Detailed Description

The present application is described in further detail below with reference to the attached drawings.

The utility model provides a spline is cold to rub milling machine for shaping with hands, refer to fig. 1 and fig. 2, including the lathe 1 that is used for rubbing the spline with hands, lathe 1 is vertical to be set up in ground, lathe 1 includes casing 31, casing 31 internal connection has the tooth piece 32 of rubbing with hands, the vertical and symmetry of tooth piece 32 of rubbing with hands sets up two, the side fixedly connected with that tooth piece 32 of rubbing with hands is close to mutually rubs pinion rack 33, two tooth pieces 32 of rubbing with hands are connected with the cylinder four 34 that is used for rubbing tooth piece 32 to go up and down, two are rubbed tooth piece 32 synchronous relative motion with hands, be close to each other simultaneously and keep away from each other simultaneously, rub pinion rack 33 and extrude the formation spline to the work piece.

Referring to fig. 1, machine tool 1 is provided with transmission device 2, transmission device 2 includes frame 11, the length direction of frame 11 is unanimous with machine tool 1's length direction, 11 length direction's of frame both ends are all rotated and are connected with belt pulley 12, two belt pulley 12 transmissions are connected with

same root belt

13, 11 lateral wall fixedly connected with motors 14 of frame, 11 lateral wall of frame and coaxial fixed connection in belt pulley 12's inner circle are worn to locate by motor 14's output shaft, the work piece is placed on belt 13, motor 14 passes through belt pulley 12 and drives belt 13 motion, and then transmit near machine tool 1 with the work piece.

Referring to fig. 2 and 3, the one end that 11 length direction of frame is close to lathe 1 is provided with moving mechanism 3, moving mechanism 3 includes support frame 15, the vertical setting of support frame 15, support frame 15 fixed connection is in ground, the length direction of support frame 15 is unanimous with the width direction of belt 13, the one end sliding connection that ground was kept away from to support frame 15 has supporting seat 16, supporting seat 16 slides along the length direction of support frame 15, spout 35 has been seted up to one side that support frame 15 is close to supporting seat 16, the length direction of spout 35 is unanimous with the length direction of support frame 15, supporting seat 16 integrated into one piece has slider 36, slider 36 sliding connection is in spout 35 and slides along the length direction of spout 35, lathe 1's three 17 of one end fixedly connected with cylinder are kept away from to spout 35, the output shaft fixed connection of three 17 of cylinder is in slider 36.

Referring to fig. 4 and 5, a support 18 is connected to one side, away from the support frame 15, of the support base 16 in a sliding manner, the support 18 slides in the vertical direction, two concave holes 37 are formed in one side, close to the support 18, of the support base 16, a first lifting cylinder 20 and a second lifting cylinder 21 are hinged in the two concave holes 37 respectively, the first lifting cylinder 20 is hinged to one end, close to the belt 13, of the support 18, the second lifting cylinder 21 is hinged to one end, away from the belt 13, of the support 18, output shafts of the first lifting cylinder 20 and the second lifting cylinder 21 are hinged to one side, close to the support base 16, of the support 18, and the upper surface of the support 18 is designed in an arc shape; frame 11 is close to support piece 18 one end fixedly connected with transition piece 29, and one side that frame 11 was kept away from to transition piece 29 is close to support piece 18, and support piece 18 one side is kept away from to transition piece 29 is close to belt 13 and is the arc setting, the transmission of the belt 13 of being convenient for.

The first lifting cylinder 20 and the second lifting cylinder 21 can control the height of the support part 18 by lifting simultaneously so as to adjust the axial height of the workpiece, so that workpieces with different diameters can be coaxially connected with the clamping mechanism 4; the first lifting cylinder extends independently, so that the support 18 is inclined to facilitate the workpiece to roll off the support 18 for blanking; the arc shape of the upper surface of the support member 18 enables the support member 18 to better conform to the outer wall of the workpiece, and the workpiece is not easy to fall off the support member 18; the transition piece 29 facilitates the transfer of work pieces from the belt 13 to the support member 18, and the arcuate configuration of the side walls of the transition piece 29 facilitates the driving of the belt 13, reducing the likelihood that the transition piece 29 will affect the driving of the belt 13.

Referring to fig. 2 and 6, a linear electric cylinder 22 is fixedly connected to one side of a support base 16, which is far away from a machine tool 1, the length direction of the linear electric cylinder 22 is perpendicular to the length direction of a support frame 15, a clamping mechanism 4 is fixedly connected to a sliding block of the linear electric cylinder 22, the clamping mechanism 4 comprises a support sleeve I5 and a support sleeve II 6, the support sleeve I5 and the support sleeve II 6 are respectively sleeved at two axial ends of a workpiece, a support column I24 is rotatably connected to one end, which is far away from the workpiece, of the support sleeve I5, a cylinder I23 is coaxially and fixedly connected to one end, which is far away from the support sleeve I5, of the support column I24, a cylinder I23 is coaxially and fixedly connected to one end, which is far away from the workpiece, of the support sleeve II 6 is rotatably connected to one end, which is far away from the cylinder II 26, of the machine tool 1 is fixedly connected to one side, which is close to the support column II 26, an output shaft of the cylinder II 25 is penetrated through a side wall of the machine tool 1 and coaxially and fixedly connected to the support column II 26, and one end, which is far away from the workpiece, is rotatably connected to one end, which is far away from the support sleeve II 26, which is far away from the cylinder II 26.

When a workpiece enters the supporting part 18, the first air cylinder 23 is arranged at one end, far away from the supporting part 18, of the linear electric cylinder 22, the influence of the first supporting column 24 and the first supporting sleeve 5 on the workpiece entering the supporting part 18 is reduced, the supporting base 16 drives the supporting part 18 to move the workpiece to the working position inside the machine tool 1, the first air cylinder 23 and the second air cylinder 25 are respectively started, the first air cylinder 23 and the second air cylinder 25 respectively drive the first supporting sleeve 5 and the second supporting sleeve 6 to move through the first supporting column 24 and the second supporting column 26, the first supporting sleeve 5 and the second supporting sleeve 6 are respectively sleeved on the two axial ends of the workpiece, when the two tooth rubbing pieces 32 move mutually, the tooth rubbing plate 33 extrudes the workpiece to drive the workpiece to roll, the first supporting sleeve 5 and the second supporting sleeve 6 simultaneously rotate along with the workpiece, and the workpiece is subjected to cold rubbing forming of the spline.

Referring to fig. 6, the through holes 7 are formed in the first supporting sleeve 5 and the second supporting sleeve 6, the inner walls of the through holes 7 are arranged in an inclined mode, one end, with the largest inner diameter, of each of the two through holes 7 is located at one end, close to the first supporting sleeve 5 and the second supporting sleeve 6, of the corresponding one-to-one, one end, with the smallest inner diameter, of each of the two through holes 7 is located at one end, far away from the first supporting sleeve 5 and the second supporting sleeve 6, of the corresponding one-to-one, and workpieces with different diameters in a certain range can be conveniently sleeved on the inclined surfaces of the first supporting sleeve 5 and the second supporting sleeve 6.

Referring to fig. 1, one side of a support frame 15, which is far away from a rack 11, is fixedly connected with a blanking mechanism 10, the blanking mechanism 10 comprises a blanking plate 27 and a collection box 28, the blanking plate 27 is arranged in an inclined manner, the highest position of an inclined plane of the blanking plate 27 is located at the joint of the support frame 15 and the blanking plate 27, the lowest position of the inclined plane of the blanking plate 27 is connected to the collection box 28, after a workpiece subjected to gear rolling is transported out through a support, an output shaft of a lifting cylinder 20 extends out to enable the support 18 to be inclined, the workpiece rolls down to the blanking plate 27 from the support 18, and the workpiece rolls from the blanking plate to the collection box 28 through self gravity on the blanking plate 27 to be collected.

The implementation principle of the implementation column of the application is as follows: the motor 14 is started, the motor 14 drives the belt 13 to transmit through the belt pulley 12, the belt 13 transmits the workpieces to the supporting piece 18 one by one, the supporting base 16 drives the supporting piece 18 to move towards the inside of the machine tool 1, and then the workpieces are moved to the working position, the supporting sleeve I5 and the supporting sleeve II 6 drive the supporting sleeve I5 and the supporting sleeve II 6 to approach to each other through the supporting column I24 and the supporting column II 26 respectively in the cylinder I23 and the cylinder II 25 respectively, when the workpieces are moved to the working position, the supporting sleeve I5 and the supporting sleeve II 6 simultaneously sleeve the two axial ends of the workpieces, so that the axial position of the workpieces is fixed, the supporting base 16 drives the supporting piece 18 to return to the initial position, the cylinder IV 34 of the tooth rubbing piece 32 is started, the tooth rubbing piece 32 approaches to each other, and the tooth rubbing plate 33 extrudes the workpieces.

After the gear rolling is finished, the gear rolling parts 32 are far away from each other, the supporting seat 16 drives the supporting part 18 to move towards the inside of the shell 31 until the supporting part 18 contacts with a workpiece, the supporting sleeve I5 and the supporting sleeve II 6 are far away from each other at the same time, the supporting sleeve I5 and the supporting sleeve II 6 loosen the workpiece, the workpiece falls on the supporting part 18, the supporting seat 16 moves outwards to an initial position, the output shaft of the lifting cylinder I20 extends out to enable the supporting part 18 to incline, the workpiece slides to the blanking plate 27 from the supporting part 18, the workpiece continuously rolls downwards to enter the collecting box 28 by means of the gravity of the workpiece on the inclined surface of the blanking plate 27, the workpiece is collected, the whole process of cold rolling forming of splines of the workpiece is finished, and the steps are repeated, so that the splines of a plurality of workpieces can be cold rolled and formed.

The above embodiments are preferred embodiments of the present application, and the protection scope of the present application is not limited by the above embodiments, so: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. Cold forming milling machine of rubbing with hands of spline is including being used for rubbing lathe (1) of spline, its characterized in that: lathe (1) is equipped with transport mechanism (2) that is used for conveying the work piece and is close to lathe (1), lathe (1) is equipped with and is used for controlling work piece to lathe (1) inside moving body (3) that removes, lathe (1) be equipped with and be used for the clamping mechanism (4) of butt different diameter work piece, clamping mechanism (4) are including supporting cover one (5) and supporting cover two (6), support cover one (5) and supporting cover two (6) and all offer through-hole (7) that are used for the work piece tip to stretch into, through-hole (7) inner wall slope sets up, the one end that two through-hole (7) internal diameters are minimum is located the one end that the support cover one (5) and support cover two (6) of one-to-correspond kept away from each other, support cover one (5) and support cover two (6) and be connected with respectively and be used for driving support cover one (5) and support cover two (6) drive assembly one (8) and drive assembly two (9) that are close to or keep away from both ends of work piece, the unloading mechanism (10) that the one end that transport mechanism (3) kept away from is connected with the work piece that is used for processing is accomplished.

2. The milling machine for cold twist forming of splines according to claim 1, characterized in that: transmission device (2) are including frame (11), and frame (11) rotate and are connected with two belt pulleys (12), and two belt pulley (12) transmissions are connected with same belt (13), and frame (11) lateral wall fixedly connected with motor (14), and frame (11) lateral wall and coaxial fixed connection in belt pulley (12) that correspond are worn to locate by the output shaft of motor (14).

3. The milling machine for cold roll forming of splines according to claim 1, wherein: the moving mechanism (3) comprises a support frame (15), the support frame (15) is connected with a support seat (16) in a sliding mode, the support frame (15) is connected with a cylinder III (17) for driving the support seat (16) to move in the horizontal direction, the support seat (16) is connected with a support piece (18) for placing a workpiece, and the support piece (18) is connected with a lifting cylinder (19) for driving the support piece (18) to move in the vertical direction.

4. The milling machine for cold twist forming of splines according to claim 3, characterized in that: lifting cylinder (19) set up two and be lifting cylinder (20) and lifting cylinder two (21) respectively, the body of lifting cylinder (20) and lifting cylinder two (21) all articulates in supporting seat (16), lifting cylinder (20) are connected in the one end that supporting seat (16) are close to frame (11), lifting cylinder two (21) are connected in the one end that supporting seat (16) kept away from frame (11), the output shaft of lifting cylinder (20) and lifting cylinder two (21) all articulates in one side that supporting piece (18) are close to supporting seat (16).

5. The milling machine for cold twist forming of splines according to claim 3, characterized in that: the surface of the support (18) contacting the workpiece is arranged in an arc shape.

6. The milling machine for cold twist forming of splines according to claim 1, characterized in that: the first driving assembly (8) comprises a linear electric cylinder (22), the linear electric cylinder (22) is fixedly connected to one side, away from the machine tool (1), of the support frame (15), a sliding block of the linear electric cylinder (22) is fixedly connected with a first air cylinder (23), an output shaft of the first air cylinder (23) is fixedly connected with a first support column (24), and a first support sleeve (5) is rotatably connected to the first support column (24); the second driving assembly (9) comprises a second air cylinder (25), the second air cylinder (25) is fixedly connected to one side, away from the supporting frame (15), of the machine tool (1), an output shaft of the second air cylinder (25) penetrates through the side wall of the machine tool (1) and is fixedly connected with a second supporting column (26) in a coaxial mode, and the second supporting sleeve (6) is rotatably connected to the second supporting column (26).

7. The milling machine for cold roll forming of splines according to claim 1, wherein: unloading mechanism (10) are including unloading board (27) and collecting box (28), and unloading board (27) fixed connection keeps away from the one side of frame (11) in support frame (15), and the one side slope setting of unloading board (27) contact work piece, and collecting box (28) are connected in the lowest of unloading board (27) inclined plane.

8. The milling machine for cold twist forming of splines according to claim 2, characterized in that: the two side walls of one end, close to the support piece (18), of the rack (11) are fixedly connected with transition pieces (29), one side, far away from the rack (11), of each transition piece (29) is close to the side wall of the support piece (18), and one side, far away from the support piece (18), of each transition piece (29) is close to the belt (13).