CN215657214U

CN215657214U - Pipe bending device

Info

Publication number: CN215657214U
Application number: CN202120231252.0U
Authority: CN
Inventors: 袁利娜
Original assignee: Avic Power Zhuzhou Aviation Parts Manufacturing Co ltd
Current assignee: Hunan Xingtu Aerospace And Spacecraft Manufacturing Co ltd
Priority date: 2021-01-27
Filing date: 2021-01-27
Publication date: 2022-01-28
Anticipated expiration: 2031-01-27

Abstract

The utility model discloses a pipe bending device, which comprises a forming supporting plate, a positioning part and a pipe bending part, wherein the side surface of the forming supporting plate, which is close to the pipe bending part, is a supporting surface with an arc corner, a first arc groove for matching with a pipe is concavely arranged on the supporting surface, the pipe bending part comprises a guide plate, a roller component and a driving part, at least one side of the first arc groove is provided with the guide plate, the guide plate is provided with a guide groove matched with the surface shape of the supporting surface, the pipe is supported by the first arc groove on the forming supporting plate, the non-bending section of the pipe is fixedly positioned, the roller component is driven by the driving part to move along the guide groove, and then the roller component rolls the pipe arranged in the first arc groove on the supporting surface, so that the pipe between the first arc groove and the second arc groove is bent and formed. According to the pipe bending device, the pipe is not damaged in the actual bending deformation process, the rejection rate is low, and the processing efficiency is high.

Description

Pipe bending device

Technical Field

The utility model relates to the technical field of aero-engine pipeline processing equipment, in particular to a pipe bending device.

Background

As shown in figure 1, a part D of a working nozzle holder assembly of an engine of a certain type is an L-shaped part with an arc corner, and the part D is a small-diameter pipe. When the working nozzle holder assembly of the engine of the type is assembled, the process requires that the first end of the part D is inserted into the part B for brazing, the fit clearance is 0.06-0.08 mm, and the end face of the second end of the part D cannot exceed the starting face of the part C. The aperture of the matching hole of the part B and the part D is phi 3.3(0.05, 0.02) mm, so the part D needs to ensure the size of phi 3.3(-0.05, -0.08 mm) in the processing process. But the dimension of the actually processed part D was measured to be Φ 3.18 to Φ 3.27 mm.

In the prior art, when a part D is bent, a small-diameter pipe is firstly placed into a vice, and the small-diameter pipe is generally clamped by a cowhide or an aluminum plate and is placed into the vice together in order to prevent the small-diameter pipe from being damaged; and then, knocking one end of the pipe by using the wood hammer or the rubber hammer, and comparing by using a sample plate to see whether the pipe is bent in place. The method for bending the small-caliber pipe has the following defects: the small-caliber pipe has larger internal and external shape change ratio in the bending process; different operators have different proficiency degrees, and the bending quality is greatly influenced by human factors; the ovality of the small-caliber pipe after bending is large, knocking marks are formed on the surface of the pipe in the subsequent correction process, and the rejection rate is high.

SUMMERY OF THE UTILITY MODEL

The utility model provides a pipe bending device, which solves the technical problems that the processing quality is greatly influenced by human factors and the rejection rate is high when the existing pipe with a small pipe diameter is bent.

In order to achieve the purpose, the technical scheme adopted by the utility model is as follows:

a pipe bending device comprises a forming supporting plate for bearing a pipe, a positioning part for positioning the pipe on the forming supporting plate and a pipe bending part for rolling the pipe on the forming supporting plate to bend and form the pipe, wherein the side surface of the forming supporting plate close to the pipe bending part is a supporting surface with an arc corner, a first arc groove for being matched with the pipe is concavely arranged on the supporting surface, the pipe bending part comprises a guiding plate, a roller component and a driving part, at least one side of the first arc groove is provided with the guiding plate, the guiding plate is provided with a guiding groove matched with the surface shape of the supporting surface, the roller component is movably matched with the guiding groove to enable the roller component to be supported on the guiding plate and arranged opposite to the first arc groove, a second arc groove for being matched with the pipe is concavely arranged on the outer circumferential surface of the roller component, the second arc groove is correspondingly arranged with the first arc groove and combined to form a matching hole matched with the outer circumference of the pipe, the pipe is loaded through the first arc groove on the forming supporting plate, the non-bending section of the pipe is fixedly positioned, the driving part drives the roller assembly to move along the guide groove, and then the roller assembly rolls the pipe arranged in the first arc groove on the supporting surface, so that the pipe between the first arc groove and the second arc groove is bent and formed.

Furthermore, the supporting surface comprises a supporting surface, an arc corner connecting surface and a bending forming bearing surface which are sequentially arranged, and a first continuous through arc groove is arranged on the supporting surface, the arc corner connecting surface and the bending forming bearing surface.

Furthermore, guide plates are arranged on two sides of the first arc groove, a positioning pressing plate for clamping and positioning the pipe on the supporting surface is adopted by the positioning portion, the positioning pressing plate is detachably connected with the forming supporting plate, a matching groove matched with the pipe is concavely arranged on the side face, close to the forming supporting plate, of the positioning pressing plate, and the non-bending section of the pipe is clamped and positioned on the supporting surface of the forming supporting plate through the positioning pressing plate.

Further, the pipe bending apparatus further comprises a mandrel assembly for supporting the pipe from an interior of the pipe, the mandrel assembly comprising a first mandrel for supporting the pipe from a first end of the pipe and a second mandrel for supporting the pipe from a second end of the pipe.

Further, the first core rod is in a step shape in appearance, the first core rod comprises a first small-diameter section and a first large-diameter section, the first small-diameter section is used for being inserted into the first end of the pipe and located at a position outside the bending area of the pipe, the first large-diameter section is used for being in butt fit with the end face of the first end of the pipe, the second core rod is in a step shape in appearance, and the second core rod comprises a second small-diameter section and a second large-diameter section, the second small-diameter section is used for being inserted into the second end of the pipe and located at a position outside the bending area of the pipe, and the second large-diameter section is used for being in butt fit with the end face of the second end of the pipe.

Further, the drive division is including locating the rocking arm in the guide board outside, the first end of rocking arm is articulated with the shaping layer board, the second end of rocking arm outwards extends and surpasss out the shape face of propping of shaping layer board and guide the board setting, set up the kidney slot of laying along the axial of rocking arm on the rocking arm, the one end that wheel components is close to the rocking arm outwards extends and stretches into to the kidney inslot, swing so that the lateral wall in kidney slot supports and holds wheel components around articulated axis through the rocking arm, and force wheel components along the guide groove motion, and then make wheel components swing along with the rocking arm is synchronous under the drive of rocking arm.

Further, the driving part also comprises a sleeve which is inserted and matched with the second end of the rocker arm so as to prolong the force application moment on the rocker arm.

Furthermore, the roller assembly comprises an assembly shaft and a rolling wheel which are coaxially arranged, the rolling wheel is supported on the assembly shaft, a second arc groove is concavely arranged on the outer circumferential surface of the rolling wheel, the rolling wheel is in rolling fit with the supporting surface, two ends of the assembly shaft extend outwards and are respectively arranged in the guide grooves on the corresponding side, the assembly shaft is in sliding fit or rolling fit with the guide grooves on the corresponding side, and one end, close to the rocker arm, of the assembly shaft penetrates through the guide grooves and extends into the kidney-shaped groove.

Further, the molding supporting plate comprises a bottom plate and a molding block which are detachably connected, one side of the molding block is detachably connected with the bottom plate, the side face, far away from the bottom plate, of the molding block is a supporting face, and an assembling boss which extends outwards and is used for assembling and positioning is arranged on the surface, far away from the molding block, of the bottom plate.

Furthermore, the surface of the bottom plate, which is close to the molded block, is concavely provided with a fixing groove matched with the molded block in an inserted manner, and one side of the molded block is inserted and arranged in the fixing groove and is fixedly connected with the bottom plate through a fastening bolt.

The utility model has the following beneficial effects:

the pipe bending device comprises a forming supporting plate, a positioning part and a pipe bending part, wherein the non-bending section of the pipe is fixed on the forming supporting plate through the positioning part, the positioning part is arranged on one side of the pipe bending part, and the pipe is swung along the bending direction through the pipe bending part and rolled on the forming supporting plate so as to be bent and formed. The side surface of the forming supporting plate is a supporting surface with an arc corner, a first arc groove is formed in the supporting surface, so that a pipe can be conveniently assembled on the supporting surface of the forming supporting plate and positioned, the pipe is supported from one side of the pipe through the forming supporting plate, and the pipe is prevented from being damaged due to stress concentration when the pipe is subjected to bending force of a bending part of the pipe; the pipe bending part comprises a guide plate, a roller assembly and a driving part, the roller assembly is guided to move along a bending path and is matched with a supporting surface through the guide plate, so that the rolled pipe is positioned between a first arc groove and a second arc groove, an operator only needs to make the roller assembly move in the guide groove in an oriented mode through force application to the driving part, the processing quality is influenced by human factors little when the pipe is bent and processed, the pipe is not damaged in the actual bending deformation process, the rejection rate is low, and the processing efficiency is high.

In addition to the objects, features and advantages described above, other objects, features and advantages of the present invention are also provided. The present invention will be described in further detail below with reference to the drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the utility model and, together with the description, serve to explain the utility model and not to limit the utility model. In the drawings:

FIG. 1 is a schematic diagram of a working nozzle block assembly for a model engine;

FIG. 2 is a schematic structural view of a pipe bending apparatus according to a preferred embodiment of the present invention;

fig. 3 is a partial structural schematic diagram of fig. 2.

Illustration of the drawings:

100. a pipe bending device; 10. forming a supporting plate; 11. a supporting surface; 12. molding blocks; 13. a base plate; 20. a pipe bending part; 21. a guide plate; 211. a guide groove; 22. a roller assembly; 221. assembling a shaft; 222. rolling wheels; 23. a drive section; 231. A rocker arm; 2311. a kidney-shaped groove; 232. a sleeve; 30. positioning a pressing plate; 40. a mandrel assembly; 41. a first core rod; 42. A second core rod.

Detailed Description

The embodiments of the utility model will be described in detail below with reference to the accompanying drawings, but the utility model can be embodied in many different forms, which are defined and covered by the following description.

FIG. 1 is a schematic diagram of a working nozzle block assembly for a model engine; FIG. 2 is a schematic structural view of a pipe bending apparatus according to a preferred embodiment of the present invention; fig. 3 is a partial structural schematic diagram of fig. 2.

As shown in fig. 2 and fig. 3, the pipe bending apparatus of this embodiment includes a forming support plate for supporting a pipe, a positioning portion for positioning the pipe on the forming support plate, and a pipe bending portion for rolling the pipe on the forming support plate to bend the pipe, a side surface of the forming support plate close to the pipe bending portion is a supporting surface with a circular arc corner, a first circular arc groove for matching with the pipe is concavely provided on the supporting surface, the pipe bending portion includes a guide plate, a roller assembly, and a driving portion, the guide plate is provided on at least one side of the first circular arc groove, the guide plate is provided with a guide groove matching with the surface shape of the supporting surface, the roller assembly is movably matched with the guide groove to support the roller assembly on the guide plate and be arranged opposite to the first circular arc groove, a second circular arc groove for matching with the pipe is concavely provided on an outer circumferential surface of the roller assembly, the second arc groove and the first arc groove are correspondingly arranged and combined to jointly form a matching hole matched with the outer circumference of the pipe, the pipe is loaded through the first arc groove on the forming supporting plate, the non-bending section of the pipe is fixedly positioned, the roller assembly is driven to move along the guide groove through the driving part, and then the roller assembly rolls the pipe arranged in the first arc groove on the supporting surface, so that the pipe between the first arc groove and the second arc groove is formed in a bending mode.

Optionally, the pipe bending part is arranged close to the arc corner of the forming support plate. The guide board can be split type design with the shaping layer board, and the guide board is fixed to be located on the wall body of shaping layer board one side, perhaps, the guide board is made with shaping layer board integrated into one piece, and the upside of shaping layer board is located to the guide board.

Optionally, according to the actual condition of the pipe in the bending process and the deformation of the pipe in the actual bending process, the angle 65 ° between the side walls at the two sides of the arc corner rebounds by 5 °, and the actual radius of the arc at the arc corner is 6 mm.

Furthermore, the supporting surface comprises a supporting surface, an arc corner connecting surface and a bending forming bearing surface which are sequentially arranged, and a first continuous through arc groove is arranged on the supporting surface, the arc corner connecting surface and the bending forming bearing surface. Optionally, in this embodiment, the pipe is supported by the supporting surface and fixed under the action of the positioning portion, and when the pipe is stressed to be bent, the outer wall surface of the bent portion of the pipe is gradually attached to the arc corner connecting surface until the bent section abuts against the bending forming abutting surface.

Furthermore, guide plates are arranged on two sides of the first arc groove, a positioning pressing plate for clamping and positioning the pipe on the supporting surface is adopted by the positioning portion, the positioning pressing plate is detachably connected with the forming supporting plate, a matching groove matched with the pipe is concavely arranged on the side face, close to the forming supporting plate, of the positioning pressing plate, and the non-bending section of the pipe is clamped and positioned on the supporting surface of the forming supporting plate through the positioning pressing plate. Both sides through first circular arc recess all are equipped with the guide board, be equipped with the guiding groove of laying along the crooked direction of circular arc corner on the guide board, the guiding groove is outside the shaping layer board, wheel components's both ends respectively with the guiding groove sliding fit who corresponds the side, so that wheel components supports and lays relatively with first circular arc recess on two guide boards, be favorable to guaranteeing that wheel components locates steadily in the guiding groove, and wheel components can not the beat when relative guide board activity, and then the machining precision when having improved crooked tubular product. Specifically, in the present embodiment, the positioning pressure plate and the forming pallet are fastened and connected by bolts.

Further, the pipe bending apparatus further comprises a mandrel assembly for supporting the pipe from an interior of the pipe, the mandrel assembly comprising a first mandrel for supporting the pipe from a first end of the pipe and a second mandrel for supporting the pipe from a second end of the pipe. Optionally, the first core rod and the second core rod are in clearance fit with the inner hole of the pipe groove respectively, and the first core rod and the second core rod are arranged to support the pipe from the inside of the pipe, so that the circumferential surface of the pipe is prevented from being stressed and deformed when the pipe is positioned or bent.

Preferably, in order to avoid the first core rod and the second core rod from being lost, the first large-diameter section of the first core rod is connected with the forming supporting plate through a tether, and the second large-diameter section of the second core rod is connected with the forming supporting plate through the tether.

Optionally, in this embodiment, the pipe bending apparatus further includes a pre-positioning block for pre-positioning the non-bending section of the pipe, and the pre-positioning block is detachably connected to the molding block of the molding support plate through a screw, so as to pre-position the pipe by abutting against the end face of the non-bending section of the pipe. Specifically, the side wall surfaces of the pre-positioning blocks and the profile blocks, which are far away from the arc corners, are attached to each other and protrude out of the supporting surface, so that the pipe is abutted against the end surface of the non-bending section of the pipe to realize pre-positioning of the pipe.

Preferably, the first core rod is in a step shape, the first core rod comprises a first small-diameter section which is used for being inserted into the first end of the pipe and is positioned outside the bending area of the pipe and a first large-diameter section which is used for being in butt fit with the end face of the first end of the pipe, the second core rod is in a step shape, and the second core rod comprises a second small-diameter section which is used for being inserted into the second end of the pipe and is positioned outside the bending area of the pipe and a second large-diameter section which is used for being in butt fit with the end face of the second end of the pipe. Optionally, in this embodiment, the first core rod is further configured to perform a pre-positioning on the tube, specifically, when the tube is assembled on the forming pallet, first, the large diameter section of the first core rod abuts against an end surface of the non-bending section of the tube and abuts against a side wall surface of a block of the forming pallet, and then the non-bending section of the tube is clamped and positioned on the supporting surface of the forming pallet by the positioning pressing plate.

Further, the drive division is including locating the rocking arm in the guide board outside, the first end of rocking arm is articulated with the shaping layer board, the second end of rocking arm outwards extends and surpasss out the shape face of propping of shaping layer board and guide the board setting, set up the kidney slot of laying along the axial of rocking arm on the rocking arm, the one end that wheel components is close to the rocking arm outwards extends and stretches into to the kidney inslot, swing so that the lateral wall in kidney slot supports and holds wheel components around articulated axis through the rocking arm, and force wheel components along the guide groove motion, and then make wheel components swing along with the rocking arm is synchronous under the drive of rocking arm. Include the rocking arm through setting up the drive division, can make roller components roll extrusion tubular product and with tubular product bending through to the rocking arm application of force after with tubular product location, easy operation, the second end through the rocking arm outwards extends and surpasss out the shaping face and the guide board setting of propping of shaping layer board, is favorable to avoiding the interference of shaping layer board and guide board to the rocking arm.

Further, in order to increase the force application torque, the driving part further comprises a sleeve which is inserted and matched with the second end of the rocker arm so as to prolong the force application torque to the rocker arm.

Furthermore, the roller assembly comprises an assembly shaft and a rolling wheel which are coaxially arranged, the rolling wheel is supported on the assembly shaft, a second arc groove is concavely arranged on the outer circumferential surface of the rolling wheel, the rolling wheel is in rolling fit with the supporting surface, two ends of the assembly shaft extend outwards and are respectively arranged in the guide grooves on the corresponding side, the assembly shaft is in sliding fit or rolling fit with the guide grooves on the corresponding side, and one end, close to the rocker arm, of the assembly shaft penetrates through the guide grooves and extends into the kidney-shaped groove. Specifically, in this embodiment, the assembly shaft is in sliding fit with the guide groove on the corresponding side, and the rolling wheel is in rolling fit with the support surface, so that in the process that the assembly shaft slides in the kidney-shaped groove, the rolling wheel synchronously moves along with the assembly shaft and rolls and assembles the pipe on the molding support plate.

Further, the molding supporting plate comprises a bottom plate and a molding block which are detachably connected, one side of the molding block is detachably connected with the bottom plate, the side face, far away from the bottom plate, of the molding block is a supporting face, and an assembling boss which extends outwards and is used for assembling and positioning is arranged on the surface, far away from the molding block, of the bottom plate. The forming supporting plate comprises a bottom plate, an assembling boss is arranged on the bottom plate, and the forming supporting plate is conveniently positioned and fastened on the operating table through the assembling boss on the bottom plate.

The pipe bending device of the utility model is used specifically:

as shown in fig. 2 and 3, the tube is supported by the opening of the large diameter section of the first core rod, the small diameter sections of the first core rod and the second core rod give way to the bending radius of the tube, the bottom plate is connected with the profile block through a screw, and the square groove is formed in the bottom plate and is in interference fit with the profile block.

When in work: the pipe bending machine is characterized in that the pipe is clamped with a vice through an assembling boss on a bottom plate, a rocker arm is placed at the position shown in figure 2, a pipe is placed on a molded surface between a molded block and a roller, two ends of the pipe are respectively inserted with a core rod, pre-positioning is carried out through a second core rod, the pipe is pressed tightly by a positioning pressing plate, the center of the molded surface on the molded block, the center of the molded surface on a roller component and the center of the pipe are on the same central line, and the pipe is bent by the rocker arm along the track of a guide groove on a guide plate through the sliding of the roller.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pipe bending device is characterized in that,

comprises a forming supporting plate (10) for bearing a pipe, a positioning part for positioning the pipe on the forming supporting plate (10) and a pipe bending part (20) for rolling the pipe on the forming supporting plate (10) to bend the pipe, wherein the side surface of the forming supporting plate (10) close to the pipe bending part (20) is a supporting surface (11) with an arc corner, a first arc groove matched with the pipe is concavely arranged on the supporting surface (11),

the pipe bending part (20) comprises a guide plate (21), a roller component (22) and a driving part (23), wherein the guide plate (21) is arranged on at least one side of the first arc groove, a guide groove (211) matched with the surface shape of the supporting surface (11) is arranged on the guide plate (21), the roller component (22) is movably matched with the guide groove (211) so that the roller component (22) is supported on the guide plate (21) and is oppositely arranged with the first arc groove, a second arc groove matched with the pipe is concavely arranged on the outer circumferential surface of the roller component (22), the second arc groove and the first arc groove are correspondingly arranged and combined to jointly form a matching hole matched with the outer circumference of the pipe,

the first arc groove on the forming supporting plate (10) bears a pipe and enables a non-bending section of the pipe to be fixedly positioned, the driving portion (23) drives the roller assembly (22) to move along the guide groove (211), and then the roller assembly (22) rolls the pipe in the first arc groove on the supporting surface (11), so that the pipe between the first arc groove and the second arc groove is formed in a bending mode.

2. Pipe bending device according to claim 1,

the supporting surface (11) comprises a supporting surface, an arc corner connecting surface and a bending forming supporting surface which are sequentially arranged, and the first arc groove which is continuously communicated is arranged on the supporting surface, the arc corner connecting surface and the bending forming supporting surface.

3. Pipe bending device according to claim 2,

the guide plates (21) are arranged on both sides of the first arc groove,

the positioning part adopts a positioning pressure plate (30) for clamping and positioning the pipe on the supporting surface,

the positioning pressing plate (30) is detachably connected with the forming supporting plate (10), a matching groove matched with the pipe is concavely arranged on the side face, close to the forming supporting plate (10), of the positioning pressing plate (30), and the non-bending section of the pipe is clamped and positioned on the supporting face of the forming supporting plate (10) through the positioning pressing plate (30).

4. Pipe bending device according to claim 1,

the pipe bending apparatus further comprises a mandrel assembly (40) for supporting the pipe from the interior of the pipe,

the mandrel assembly (40) includes a first mandrel (41) for supporting a tubular from a first end of the tubular and a second mandrel (42) for supporting a tubular from a second end of the tubular.

5. The pipe bending apparatus according to claim 4,

the first core rod (41) is in a step shape, the first core rod (41) comprises a first small-diameter section which is used for being inserted into the first end of the pipe and is positioned outside the bending area of the pipe and a first large-diameter section which is used for being abutted and matched with the end surface of the first end of the pipe,

the second core rod (42) is in a step shape, and the second core rod (42) comprises a second small-diameter section and a second large-diameter section, wherein the second small-diameter section is used for being inserted into the second end of the pipe and is positioned outside the bending area of the pipe, and the second large-diameter section is used for being abutted and matched with the end face of the second end of the pipe.

6. Pipe bending device according to claim 1,

the driving part (23) comprises a rocker arm (231) arranged on the outer side of the guide plate (21), the first end of the rocker arm (231) is hinged to the molding supporting plate (10), the second end of the rocker arm (231) extends outwards and exceeds the supporting surface (11) of the molding supporting plate (10) and the guide plate (21), a kidney-shaped groove (2311) distributed along the axial direction of the rocker arm (231) is formed in the rocker arm (231), one end, close to the rocker arm (231), of the roller component (22) extends outwards and extends into the kidney-shaped groove (2311),

the side wall of the kidney-shaped groove (2311) is abutted against the roller assembly (22) by swinging the rocker arm (231) around a hinge axis, the roller assembly (22) is forced to move along the guide groove (211), and the roller assembly (22) is driven by the rocker arm (231) to synchronously swing along with the rocker arm (231).

7. The pipe bending apparatus according to claim 6,

the driving part (23) further comprises a sleeve (232) which is inserted and matched with the second end of the rocker arm (231) so as to prolong the force application moment on the rocker arm (231).

8. The pipe bending apparatus according to claim 6,

the roller assembly (22) comprises an assembling shaft (221) and a rolling wheel (222) which are coaxially arranged, the rolling wheel (222) is supported on the assembling shaft (221), the outer circumferential surface of the rolling wheel (222) is concavely provided with a second arc groove, the rolling wheel (222) is in rolling fit with the supporting surface (11),

two ends of the assembling shaft (221) extend outwards and are respectively arranged in the guide grooves (211) on the corresponding side, the assembling shaft (221) is in sliding fit or rolling fit with the guide grooves (211) on the corresponding side, and one end, close to the rocker arm (231), of the assembling shaft (221) penetrates through the guide grooves (211) and extends into the kidney-shaped groove (2311).

9. Pipe bending device according to claim 1,

the molding supporting plate (10) comprises a bottom plate (13) and a molding block (12) which are detachably connected, one side of the molding block (12) is detachably connected with the bottom plate (13), the side surface of the molding block (12) far away from the bottom plate (13) is the supporting surface (11),

and an assembling boss which extends outwards and is used for assembling and positioning is arranged on the surface of the bottom plate (13) far away from the section block (12).

10. Pipe bending device according to claim 9,

the surface of the bottom plate (13) close to the molding block (12) is concavely provided with a fixing groove matched with the molding block (12) in an inserted mode, and one side of the molding block (12) is inserted into the fixing groove and is fixedly connected with the bottom plate (13) through a fastening bolt.