CN210629259U

CN210629259U - Electric cylinder turns back

Info

Publication number: CN210629259U
Application number: CN201921550841.4U
Authority: CN
Inventors: 周井志
Original assignee: Shanghai Wende Automation Technology Co Ltd
Current assignee: Shanghai Wende Automation Technology Co Ltd
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2020-05-26
Anticipated expiration: 2029-09-17

Abstract

The utility model relates to a turn-back electric cylinder, which comprises a base, a motor arranged on the base, a belt pulley component driven by the motor to rotate, a cylinder body fixed on the base and positioned at one side of the motor, and a transmission mechanism driven by the belt pulley component; the transmission mechanism comprises a screw rod, a transmission rod in threaded fit with the screw rod and a guide assembly for guiding the transmission rod; the cylinder body is close to the one end of base and is provided with the bearing frame, the bearing frame is fixed in the base, be provided with the carrier assembly in the bearing frame, the carrier assembly includes the bearing, and set up in the first carrier ring of bearing inner circle, first carrier ring includes first sleeve, and set up perpendicularly in first telescopic first carrier ring, the periphery side of lead screw is located to first sleeve cover, first carrier ring joint is between lead screw and bearing, the up end butt in the lead screw of first carrier ring, the lower terminal surface butt in the bearing of first carrier ring. The utility model discloses have the life of extension lead screw, reduce the effect of the change frequency of lead screw.

Description

Electric cylinder turns back

Technical Field

The utility model belongs to the technical field of mechanical transmission equipment's technique and specifically relates to an electronic jar of turning back is related to.

Background

The electric cylinder can be divided into a linear electric cylinder and a folding electric cylinder, and the working principle is as follows: the rotary motion of the motor is converted into the linear motion of the screw rod, and the transmission precision is controlled by accurately controlling the revolution.

The motor of the linear electric cylinder is connected with the electric cylinder, namely the electric cylinder and the motor are in the same straight line; the motor of the folding electric cylinder is arranged in parallel with the electric cylinder, and the middle of the folding electric cylinder is connected through a belt pulley. In general, the total length of the folding electric cylinder is shorter, and the length of the linear electric cylinder is longer, so that the folding electric cylinder saves more installation space than the linear electric cylinder when being installed. Therefore, the application of the folding electric cylinder is wider.

The existing Chinese utility model with patent publication number CN206790277U discloses a folding electric cylinder, which comprises a base, a screw rod, a pressure rod, a motor and a shell for accommodating the screw rod and the pressure rod, wherein an output shaft of the motor is in driving connection with one end of the screw rod so as to enable the pressure rod matched with the screw rod to reciprocate along the axial direction of the screw rod; the casing includes preceding cylinder liner, back cylinder liner, cylinder body and a plurality of loop bars, preceding cylinder liner with back cylinder liner respectively with the both ends lock of cylinder body, the loop bar is in order can dismantle the mode and along the periphery wall interval of cylinder body is fixed in preceding cylinder liner with between the back cylinder liner, the loop bar with the cooperation is hugged closely to the cylinder body outer wall.

Through the technical scheme, the folding electric cylinder is formed by enclosing the front cylinder sleeve, the cylinder body and the rear cylinder sleeve, and the front cylinder sleeve, the rear cylinder sleeve and the cylinder body are fixedly locked through the loop bar, so that the folding electric cylinder is convenient to assemble, disassemble and maintain, and all parts of the shell can be disassembled, can be independently subjected to die sinking processing, are independently verified and detected, and are independently repaired, so that the labor cost, the processing cost and the maintenance cost are greatly saved, and the overall cost of the folding electric cylinder is reduced.

However, in the above technical scheme, the bearing capacity of the lead screw is poor, and after the electric cylinder works for a long time, the lead screw is easily damaged due to overload, so that the lead screw needs to be frequently replaced to ensure the normal work of the electric cylinder.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an electronic jar of turning back through the bearing capacity who shares the lead screw to the life of extension lead screw reduces the change frequency of lead screw.

The above utility model discloses an above-mentioned utility model purpose can realize through following technical scheme:

a turn-back electric cylinder comprises a base, a motor, a belt pulley assembly, a cylinder body and a transmission mechanism, wherein the motor is mounted on the base; the transmission mechanism comprises a screw rod, a transmission rod and a guide assembly, wherein one end of the screw rod is connected with the belt assembly, the transmission rod is in threaded fit with the screw rod, and the guide assembly guides the transmission rod; the cylinder body is close to the one end of base and is provided with the bearing frame, the bearing frame is fixed in the base, be provided with bearing assembly in the bearing frame, bearing assembly include the bearing and set up in the first carrier of bearing inner race holds the piece, first carrier include first sleeve and set up perpendicularly in the first carrier ring of first sleeve one end, first sleeve cover is located the periphery side of lead screw, first carrier ring joint in the lead screw with between the bearing, the up end butt of first carrier ring in the lead screw, the lower terminal surface butt of first carrier ring in the bearing.

By adopting the technical scheme, the screw rod comprises two sections with different diameters, and the diameter of the screw rod is gradually reduced towards the direction close to the base, wherein the upper end face of the first bearing ring is abutted against one side with the larger diameter of the screw rod and can support the screw rod, so that the axial force of the screw rod is shared; in addition, the lower end face of the first bearing ring is abutted to the bearing, and meanwhile, the bearing can share the axial force of the first bearing ring, namely the axial force of the screw rod, so that the axial force borne by the screw rod is reduced, and the service life of the screw rod is prolonged.

The utility model discloses further set up to: and a fixed seat is arranged below the bearing close to the base, is fixedly arranged on the outer peripheral side of the screw rod and is positioned in the base, and is abutted against the bearing close to the base.

Through adopting above-mentioned technical scheme, set up the fixing base, the fixing base supports in the bearing below that is close to the base setting, can carry on spacingly to the bearing that is close to the base setting to prevent to be close to the bearing gliding of base setting, simultaneously, the axial bearing capacity of increase bearing, the life of extension lead screw.

The utility model discloses further set up to: the bearing seat is characterized in that the inner ring of the bearing seat is provided with a limiting ring, and the bearings positioned on the upper side and the lower side of the limiting ring are respectively abutted against the upper end face and the lower end face of the limiting ring.

By adopting the technical scheme, the limiting ring is arranged, and the limiting ring and the fixed seat can simultaneously support the bearing so as to reduce the axial force action of the first bearing ring; the service life of the first bearing piece is prolonged, so that the first bearing piece, the bearing and the fixing seat share the axial force of the screw rod, and the service life of the screw rod is prolonged.

The utility model discloses set up further to the direction subassembly includes the adapter sleeve, adapter sleeve fixed connection in the one end of transfer line, the transfer line with the one end that the adapter sleeve is connected is provided with and is annular breach, the longitudinal section of breach is "┐" style of calligraphy, the adapter sleeve inlays to be located the breach just adapter sleeve screw-thread fit in the periphery side of transfer line.

By adopting the technical scheme, the end, matched with the connecting sleeve, of the transmission rod is provided with the notch with the longitudinal section in the shape of ┐, the connecting sleeve is embedded in the notch, the connecting sleeve is in threaded fit with the transmission rod, and the connecting sleeve is embedded in the notch of the transmission rod, so that the connecting sleeve can support the transmission rod, and the transmission rod is in threaded fit with the screw rod, therefore, the transmission rod and the screw rod can be seen as a whole, namely the connecting sleeve can support the screw rod, the axial force of the screw rod is shared, and the service life of the screw rod is.

The utility model discloses further set up to: the direction subassembly still includes the installation cover, the installation cover with adapter sleeve integrated into one piece, the installation cover with it holds carrier to be provided with the second between the lead screw, the second holds carrier and includes the second sleeve and set up perpendicularly in the second of second sleeve one end bears the ring, the second sleeve is located the installation cover with between the lead screw, the second bears the ring support in the installation cover is kept away from the one end of adapter sleeve.

By adopting the technical scheme, the second bearing part comprises a second sleeve and a second bearing ring, wherein the second bearing ring is vertically arranged at one end of the second sleeve, the second sleeve is sleeved on the outer peripheral side of the screw rod, and the second bearing ring is supported at one end, far away from the connecting sleeve, of the mounting sleeve, so that the second bearing ring can share the axial force for the mounting sleeve; the mounting sleeve is integrally formed on the connecting sleeve, the connecting sleeve is fixedly connected with the transmission rod, and the transmission rod is fixedly connected with the screw rod, so that the second bearing ring can share axial force for the screw rod, the load of the screw rod is reduced, and the service life of the screw rod is prolonged.

The utility model discloses further set up to: the second bearing ring is detachably fixed on the mounting sleeve through a fastening bolt, a cushion pad is arranged between the second bearing ring and the bearing seat, and the cushion pad is located below the fastening bolt.

By adopting the technical scheme, the cushion pad is arranged, so that the possibility of strong impact between the fastening bolt and the bearing seat when the electric cylinder is turned back can be reduced, and the possibility of damage to the second bearing ring caused by the fastening bolt when the electric cylinder is turned back is reduced; the service life of the second bearing ring is prolonged, so that the second bearing ring shares part of load of the screw rod, and the service life of the screw rod is further prolonged.

The utility model discloses further set up to: the connecting sleeve and the mounting sleeve are respectively provided with a wear-resistant ring, the outer diameter of the connecting sleeve and the mounting sleeve is smaller than the inner diameter of the cylinder body, and the outer side wall of the wear-resistant ring is abutted against the inner side wall of the cylinder body.

By adopting the technical scheme, the connecting sleeve and the mounting sleeve are respectively provided with the wear-resistant ring, and the wear-resistant rings are abutted against the inner side wall of the cylinder body, so that the stability of the transmission rod during transmission can be ensured, and the effect of reducing noise is achieved; in addition, the wear-resisting ring is abutted to the inner side wall of the cylinder body, but the connecting sleeve is not directly abutted to the inner side wall of the cylinder body, so that the service life of the connecting sleeve and the mounting sleeve is prolonged, the load of the screw rod is shared, and the service life of the screw rod is prolonged.

The utility model discloses further set up to: the lateral wall of installation cover is provided with the guide block, the cylinder body is provided with along the length direction of cylinder body with the guide block assorted, for the gliding guide way of guide block.

Through adopting above-mentioned technical scheme, it is spacing at the spacing inslot with the guide block to the installation cover with guide block fixed connection can't rotate, and adapter sleeve and installation cover integrated into one piece, and adapter sleeve and transfer line pass through screw-thread fit and realize fixed connection, thereby the transfer line can't rotate, and when motor drive pulley subassembly drove the lead screw and rotates, the transfer line can only be along the length direction of guide way and make linear motion.

The utility model discloses further set up to: the transfer line is kept away from the one end of adapter sleeve is connected with the piston rod, the piston rod is located the outside of cylinder body, the cylinder body is kept away from the one end of base is provided with fixed cover, fixed cover with be provided with the uide bushing between the transfer line, the inside wall of uide bushing with the lateral wall looks butt of transfer line.

Through adopting above-mentioned technical scheme, the one end that the base was kept away from to the cylinder body sets up fixed cover, and the interior periphery side of fixed cover sets up the uide bushing, and the uide bushing cover is established at the lateral wall of transfer line and with the lateral wall looks butt of transfer line to the uide bushing can further lead for the transfer line, makes the piston rod move along linear direction.

To sum up, the utility model discloses a beneficial technological effect does: the screw rod comprises two sections with different diameters, and the diameter of the screw rod is gradually reduced towards the direction close to the base, wherein the upper end face of the first bearing ring is abutted against one side with the larger diameter of the screw rod and can support the screw rod, so that the axial force of the screw rod is shared; in addition, the lower end face of the first bearing ring is abutted to the bearing, and meanwhile, the bearing can share the axial force of the first bearing ring, namely the axial force of the screw rod, so that the axial force borne by the screw rod is reduced, the service life of the screw rod is prolonged, and the replacement frequency of the screw rod is reduced.

Drawings

Fig. 1 is a partial sectional view of the present embodiment.

Fig. 2 is a sectional view of the entire structure of the present embodiment.

Fig. 3 is a partially enlarged schematic view of a portion a in fig. 2.

Fig. 4 is a partially enlarged schematic view of a portion B in fig. 2.

In the figure, 1, a base; 11. a fixed seat; 2. a motor; 3. a pulley assembly; 31. a synchronizing wheel; 32. a synchronous belt; 4. a cylinder body; 41. a bearing seat; 411. a limiting ring; 42. fixing a sleeve; 421. a guide sleeve; 43. a guide groove; 51. a bearing; 52. a first bearing member; 521. a first sleeve; 522. a first load ring; 6. a screw rod; 7. a transmission rod; 81. connecting sleeves; 82. installing a sleeve; 821. a guide block; 83. a wear ring; 84. a second bearing member; 841. a second sleeve; 842. a second load ring; 9. a piston rod; 10. a cushion pad.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 1 and 2, the foldback electric cylinder disclosed in this embodiment includes a base 1, a motor 2 fixedly mounted on the base 1 through bolts, a pulley assembly 3 driven by the motor 2 to rotate, a cylinder block 4 disposed in parallel with the motor 2, and a transmission mechanism located in the cylinder block 4 and driven by the pulley assembly 3 to perform transmission. Wherein, the two ends of the cylinder body 4 are respectively connected with a bearing seat 41 and a fixing sleeve 42, the bearing seat 41 is fixed on the base 1, and the fixing sleeve 42 is far away from the base 1.

Pulley assembly 3 comprises two synchronizing wheels 31 connected by a synchronizing belt 32; the transmission mechanism comprises a screw rod 6 positioned in the cylinder body 4, a transmission rod 7 in threaded connection with the outer periphery side of the screw rod 6, and a guide assembly for guiding the linear transmission of the transmission rod 7. One synchronizing wheel 31 is fixedly connected with an output shaft of the motor 2, and the other synchronizing wheel 31 is fixedly connected with the screw rod 6, so that the motor 2 can be driven to rotate to drive the synchronizing wheel 31 to rotate, the synchronizing wheel 31 drives the screw rod 6 to rotate, and then the transmission rod 7 is driven to transmit along the linear direction under the guiding action of the guiding assembly. In addition, one end of the transmission rod 7, which is far away from the base 1, is connected with a piston rod 9, and the piston rod 9 is in threaded connection with the transmission rod 7, so that the piston rod 9 can move linearly along with the transmission rod 7. In order to further guide the transmission rod 7 and ensure that the piston rod 9 moves along the linear direction, a guide sleeve 421 is arranged between the fixed sleeve 42 and the transmission rod 7, and the inner side wall of the guide sleeve 421 is abutted to the outer side wall of the transmission rod 7.

The guide assembly includes a connection sleeve 81 screwed to one end of the transmission rod 7, a mounting sleeve 82 integrally formed with the connection sleeve 81, and a guide block 821 provided on an outer peripheral side of the mounting sleeve 82. In this embodiment, the guide blocks 821 are provided in two sets, and the two sets of guide blocks 821 are symmetrically provided. Further, the guide groove 43 is provided on the inner wall of the cylinder 4 corresponding to the guide block 821, the guide groove 43 is provided along the longitudinal direction of the cylinder 4, the guide block 821 is positioned in the guide groove 43, and the guide block 821 is slidably connected to the guide groove 43. The guide block 821 limits the guide block 821 in the guide groove 43 through the guide block 821, so that the connecting sleeve 81 and the mounting sleeve 82 cannot rotate along with the screw rod 6, and the transmission rod 7 cannot rotate because the connecting sleeve 81 is fixedly connected with the transmission rod 7, so that the transmission rod 7 transmits along a linear direction when the screw rod 6 rotates. In order to reduce the friction force when the guide block 821 slides, in the embodiment, the guide block 821 is a copper block, which has the advantages of wear resistance and small friction force.

The end of the transmission rod 7 connected with the connecting sleeve 81 is provided with an annular gap, the longitudinal section of the gap is shaped like ┐, the connecting sleeve 81 is embedded in the gap, the inner ring of the connecting sleeve 81 is in threaded fit with the outer periphery of the transmission rod 7, and the connecting sleeve 81 is embedded in the gap of the transmission rod 7, so that the connecting sleeve 81 can support the transmission rod 7.

Referring to fig. 2 and 3, a second bearing member 84 is sleeved between the mounting sleeve 82 and the lead screw 6, and the second bearing member 84 includes a second sleeve 841 and a second bearing ring 842 perpendicular to the second sleeve 841 and disposed at one end of the second sleeve 841. The second sleeve 841 is integrally formed with the second carrying ring 842, and the second sleeve 841 and the second carrying ring 842 have a cross-section of a '+' shape. The second sleeve 841 is located between the mounting sleeve 82 and the screw rod 6, and the second sleeve 841 is sleeved on the outer peripheral side of the screw rod 6; the second bearing ring 842 is supported at an end of the mounting sleeve 82 away from the connection sleeve 81, and is beneficial for supporting the mounting sleeve 82. In addition, the second bearing ring 842 is detachably fixed to the mounting sleeve 82 through fastening bolts, and a cushion pad 10 is disposed between the second bearing ring 842 and the base 1, and the cushion pad 10 is located below the fastening bolts. When the electric cylinder turns back, the problem that the fastening bolt directly collides with the base 1 to cause the fastening bolt to act on the second bearing ring 842 to damage the second bearing ring 842 can be prevented.

In order to prevent the problem that the connecting sleeve 81 and the mounting sleeve 82 generate friction on the inner wall of the cylinder body 4 in the transmission process, the outer diameters of the connecting sleeve 81 and the mounting sleeve 82 are smaller than the inner diameter of the cylinder body 4, but noise of the transmission rod 7 in the transmission process is easy to increase, so that wear-resistant rings 83 are respectively embedded on the outer peripheral sides of the connecting sleeve 81 and the mounting sleeve 82, and the wear-resistant rings 83 abut against the inner side wall of the cylinder body 4, so that stability of the transmission rod 7 in the transmission process can be ensured, and the noise is reduced. In addition, in this embodiment, the wear-resistant ring 83 is made of a wear-resistant nylon material, which is beneficial to prolonging the service life of the wear-resistant ring 83.

Referring to fig. 2 and 4, a bearing assembly is arranged in the bearing seat 41, the bearing assembly includes a bearing 51 mounted on an inner ring of the bearing seat 41, and a first bearing 52 arranged on an inner ring of the bearing 51, the first bearing 52 includes a first sleeve 521 sleeved on an outer peripheral side of the screw rod 6, and a first bearing ring 522 integrally formed with the first sleeve 521, the first bearing ring 522 is arranged perpendicular to the first sleeve 521, and longitudinal sections of the first bearing ring 522 and the first sleeve 521 are shaped like a letter "┐", wherein the screw rod 6 includes two sections with different diameters, and the diameter of the screw rod 6 is gradually reduced toward a direction close to the base 1, in addition, an upper end surface of the first bearing ring 522 abuts against a side with a larger diameter of the screw rod 6, and a lower end surface of the first bearing ring abuts against an end surface of the bearing 51, so that the first bearing ring 522 can support the screw rod 522, thereby dispersing an axial force of the screw rod 522.

In this embodiment, the number of the bearings 51 is two, the inner ring of the bearing seat 41 is provided with the limit ring 411, the two bearings 51 are respectively located on the upper end surface and the lower end surface of the limit ring 411, and the two bearings 51 are abutted to the limit ring 411. The first bearing ring 522 is clamped on the upper end face of the bearing 51 far away from the base 1, the fixing seat 11 is arranged below the bearing 51 close to the base 1, and the fixing seat 11 is in threaded fit with the outer peripheral side of the screw rod 6. In order to prevent the fixing seat 11 from sliding downwards, the fixing seat 11 is limited on the screw rod 6 through a bolt. In addition, the fixed seat 11 abuts against the bearing 51 close to the base 1, which is beneficial to providing support for the bearing 51 close to the base 1.

The implementation principle of the embodiment is as follows: the screw rod 6 comprises two sections with different diameters, and the diameter of the screw rod 6 is gradually reduced towards the direction close to the base 1, wherein the upper end face of the first bearing ring 522 is abutted against one side with the larger diameter of the screw rod 6, and can support the screw rod 6, so that the axial force of the screw rod 6 is shared; in addition, the lower end surface of the first bearing ring 522 is abutted to the bearing 51, and meanwhile, the bearing 51 can share the axial force of the first bearing ring 522, namely, share the axial force of the screw rod 6, so that the axial force borne by the screw rod 6 is reduced, the service life of the screw rod 6 is prolonged, and the replacement frequency of the screw rod 6 is reduced.

The embodiment of this specific implementation mode is the preferred embodiment of the present invention, not limit according to this the utility model discloses a protection scope, so: all equivalent changes made according to the structure, shape and principle of the utility model are covered within the protection scope of the utility model.

Claims

1. A turn-back electric cylinder comprises a base (1), a motor (2) arranged on the base (1), a belt pulley assembly (3) driven by the motor (2) to rotate and arranged on the base (1), a cylinder body (4) fixed on the base (1) and located on one side of the motor (2), and a transmission mechanism located in the cylinder body (4) and driven by the belt pulley assembly (3); the transmission mechanism comprises a screw rod (6) with one end connected with the belt assembly, a transmission rod (7) in threaded fit with the screw rod (6), and a guide assembly for guiding the transmission rod (7); the method is characterized in that: one end of the cylinder body (4) close to the base (1) is provided with a bearing seat (41), the bearing seat (41) is fixed on the base (1), a bearing assembly is arranged in the bearing seat (41), the bearing assembly comprises a bearing (51) and a first bearing piece (52) arranged at the inner ring of the bearing (51), the first bearing piece (52) comprises a first sleeve (521) and a first bearing ring (522) vertically arranged at one end of the first sleeve (521), the first sleeve (521) is sleeved on the outer peripheral side of the screw rod (6), the first bearing ring (522) is clamped between the screw rod (6) and the bearing (51), the upper end face of the first bearing ring (522) is abutted against the screw rod (6), and the lower end face of the first bearing ring (522) is abutted against the bearing (51).

2. A reentry electric cylinder according to claim 1, wherein: a fixed seat (11) is arranged below the bearing (51) close to the base (1), the fixed seat (11) is arranged on the outer peripheral side of the screw rod (6) and is positioned in the base (1), and the fixed seat (11) is abutted against the bearing (51) close to the base (1).

3. A reentry electric cylinder according to claim 1, wherein: the inner ring of the bearing seat (41) is provided with a limiting ring (411), and the bearings (51) positioned on the upper side and the lower side of the limiting ring (411) are respectively abutted to the upper end face and the lower end face of the limiting ring (411).

4. A turn-back electric cylinder according to claim 1, wherein the guide assembly comprises a connecting sleeve (81), the connecting sleeve (81) is fixedly connected to one end of the transmission rod (7), an annular gap is arranged at one end of the transmission rod (7) connected with the connecting sleeve (81), the longitudinal section of the gap is shaped like ┐, the connecting sleeve (81) is embedded in the gap, and the connecting sleeve (81) is in threaded fit with the outer peripheral side of the transmission rod (7).

5. A reentry electric cylinder according to claim 4, wherein: the direction subassembly still includes installation cover (82), installation cover (82) with adapter sleeve (81) integrated into one piece, installation cover (82) with it holds carrier (84) to be provided with the second between lead screw (6), second hold carrier (84) including second sleeve (841) and set up perpendicularly in the second of second sleeve (841) one end bears ring (842), second sleeve (841) are located installation cover (82) with between lead screw (6), second bear ring (842) support in installation cover (82) is kept away from the one end of adapter sleeve (81).

6. A reentry electric cylinder according to claim 5, wherein: the second bearing ring (842) is detachably fixed on the mounting sleeve (82) through a fastening bolt, a cushion pad (10) is arranged between the second bearing ring (842) and the bearing seat (41), and the cushion pad (10) is positioned below the fastening bolt.

7. A reentry electric cylinder according to claim 5, wherein: the connecting sleeve (81) and the mounting sleeve (82) are respectively provided with a wear-resistant ring (83), the outer diameters of the connecting sleeve (81) and the mounting sleeve (82) are smaller than the inner diameter of the cylinder body (4), and the outer side wall of the wear-resistant ring (83) is abutted to the inner side wall of the cylinder body (4).

8. A reentry electric cylinder according to claim 5, wherein: the outer side wall of the mounting sleeve (82) is provided with a guide block (821), and the cylinder body (4) is provided with a guide groove (43) which is matched with the guide block (821) and used for the guide block (821) to slide along the length direction of the cylinder body (4).

9. A reentry electric cylinder according to claim 4, wherein: keep away from transfer line (7) the one end of adapter sleeve (81) is connected with piston rod (9), piston rod (9) are located the outside of cylinder body (4), cylinder body (4) are kept away from the one end of base (1) is provided with fixed cover (42), fixed cover (42) with be provided with uide bushing (421) between transfer line (7), the inside wall of uide bushing (421) with the lateral wall looks butt of transfer line (7).