CN210023507U - Lower die and lower die assembly for bending machine - Google Patents

Abstract

The utility model discloses a lower mould and lower mould subassembly for bender belongs to bender mould field. The device comprises a lower die, a die holder, an adjusting block, a top block, a stop block, a cover plate, a plurality of groups of wedge blocks and a base, wherein the lower die, the die holder, the adjusting block, the cover plate, the plurality of groups of wedge blocks and the base are fixedly connected in sequence from top to bottom; the die holder is provided with an installation platform matched with the installation groove and used for installing a lower die; the adjusting block, the jacking block and the stop block are matched in relative positions and used for adjusting the horizontal position of the adjusting block; the inclined planes of the multiple groups of wedge blocks are concave-convex in wave shape and used for carrying out deflection compensation on the workpiece. The utility model discloses a lower mould can be bent the panel of different thickness under the prerequisite of not changing the lower mould, and avoids complicated upper and lower mould calibration, carries out the deflection compensation to the work piece simultaneously, simple structure, reasonable in design, easily manufacturing.

Description

Lower die and lower die assembly for bending machine

Technical Field

The utility model belongs to bender mould field, more specifically say, relate to a lower mould and lower mould subassembly for bender.

Background

The bending machine mould is a tool for forming and processing the plate material by the bending machine, the tool is composed of various parts, different moulds are composed of different parts, the processing of the appearance of an article is realized mainly by changing the physical state of the formed material, and the bending machine mould is used for enabling a blank to be a tool for forming a workpiece with a specific shape and a specific size under the action of the pressure of the bending machine. The bending machine die comprises an upper die and a lower die of a bending machine and is used for stamping and forming and separating a plate, the die for forming is provided with a cavity, and the die for separating is provided with a cutting edge. The lower die is generally a cuboid, and notches with various sizes can be opened on the lower die, and the sizes of the notches are different according to needs.

The bending force of the bending machine is completed by driving the tool rest to drive the bending die through the oil cylinder, the upper die is installed on the tool rest and moves up and down along with the tool rest, the lower die is fixed on the workbench, and the tool rest drives the upper die to move relative to the lower die to realize the bending motion. The processing width of the plate bending machine is also increased along with the change of raw materials, the width of the die reaches 3-4 m, the die with the size is heavy and high in cost, and the upper die and the lower die are often required to be replaced when plates with different thicknesses are processed.

After replacement, the upper die blade is required to be aligned with the notch of the lower die, the upper die is installed on the tool rest during operation, then the lower die is placed on the workbench, and the position is continuously adjusted to be aligned. Generally, the manual work is promoted the bed die and is removed at present through workman's visual observation, perhaps strikes the bed die adjustment through the metal block, and the bed die is generally heavier, and the people pushes away comparatively hard, and the adjustment time is longer, strikes the adjustment not only slow, and the noise is big, and can cause the damage to the bed die surface.

For example, chinese patent application No. 201210314815.8, the publication of utility model patent with publication date of 2012, 12 and 12, discloses a lower die of a bending machine and an auxiliary mechanism thereof. The lower die is provided with at least two-sided V-shaped grooves, the auxiliary mechanism is fixed on two sides of one V-shaped groove and comprises a movable positioning plate, a spring, a bushing, a guide screw and a base, the guide screw is vertically connected with the movable positioning plate, the bushing is arranged between the guide screw and the movable positioning plate, the guide screw penetrates through the spring and presses the spring under the movable positioning plate, and the bottom of the guide screw is fixed on the base; the auxiliary mechanism is also provided with rollers which are arranged on two sides of the top of another V-shaped groove, and the inclined surface of the V-shaped groove is tangent or intersected with the circumferential surface of the roller. However, when the double-sided V-groove lower die is subjected to face changing, the auxiliary mechanisms on the two sides of the V-groove for the previous bending work need to be detached, and after the V-groove on the other side of the lower die is turned over to be a horizontal plane, the auxiliary mechanisms are mounted on the two sides of the V-groove used in the current bending work again, which is very troublesome; generally, the lower die is very stressed in bending work, the lower die is fixed on a base of an auxiliary mechanism through screws, the base is easy to damage, in the bending work, once the screws are damaged, the bending precision cannot be guaranteed, hidden dangers exist in the bending process, labor is wasted, the lower die is unstable in installation, and workers are easy to hurt.

On the other hand, when the bending machine bends a plate, the bending machine inevitably generates downward elastic deformation due to insufficient rigidity of a workbench, so that the same deformation of a die arranged at the upper end of the workbench is caused, the depth of the upper die entering the lower die is reduced, the pressure distribution between the dies is uneven during bending, the pressure at two ends in the length direction of the die is larger than that at the middle, although the deformation amount is extremely small, for a high-precision bending workpiece, the workpiece is still easy to generate deflection deformation, the full-length consistency of the angle cannot be ensured, the middle of the bending angle of the workpiece is larger than that at two ends, and the middle of the linearity is smaller than that at two ends. Therefore, when designing the bending machine die, it is necessary to take corresponding measures to compensate or reduce the bending deformation generated by the bending machine die.

Therefore, in order to process plate materials with different thicknesses, to avoid the need to perform the alignment of the upper and lower dies again for the purpose of changing the dies, and to reduce the flexural deformation of the lower die, it is necessary to develop a lower die for a bending machine and a lower die assembly.

Disclosure of Invention

1. Problems to be solved

The utility model provides a lower mould for bending machine, the problem of different lower moulds need be changed to the panel of the different thickness of bending to its aim at solution current bender mould.

The utility model discloses a lower mould for bending machine still further solves the problem of lower mould location difficulty.

The utility model also provides a lower die assembly for bender, its aim at solve bender workstation direct contact lower mould and receive the impact of bending force big, cause the problem of its damage.

The utility model provides a bender is with lower mould subassembly still further solves the amount of deflection bending that produces because of the lower mould, and the crooked problem of the amount of deflection that makes the corresponding production of work piece guarantees the full length uniformity of work piece bending angle and the straightness accuracy of work piece.

2. Technical scheme

In order to solve the above problems, the utility model adopts the following technical proposal.

A lower die for a bending machine is provided with two bending grooves on at least one side surface, the depths of the two bending grooves are different, and mounting grooves are formed in the opposite side surfaces of the two bending grooves on the side surface of the lower die; the distances from the symmetrical middle lines of the two bending grooves to the symmetrical middle line of the mounting groove are equal.

Further, the cross section of the lower die is polygonal and has even number of sides, that is, the cross section of the lower die is quadrilateral, hexagonal, octagonal, etc., preferably the cross section of the lower die is quadrilateral.

In a possible embodiment of the present invention, the lower mold is a rectangular parallelepiped, and the two adjacent side surfaces thereof are provided with bending grooves and the other two side surfaces thereof are provided with mounting grooves.

In a possible embodiment of the present invention, the bending groove is a V-shaped groove, and the mounting groove is a rectangular groove.

Furthermore, the bottom of the bending groove is provided with an avoiding groove which is used as an avoiding space for releasing stress at the bending part of the workpiece.

A lower die assembly for a bending machine comprises the lower die for the bending machine and a die holder; the die holder is provided with an installation platform matched with the installation groove of the lower die.

In a possible embodiment of the present invention, the mounting table has an upper surface provided with a wear-resistant layer for reducing the friction loss of the mounting table, and a lower mounting groove is also provided with a wear-resistant layer for reducing the loss caused by the friction between the mounting groove and the mounting table.

In a possible embodiment of the present invention, the device further comprises a cover plate, a base and a plurality of wedge blocks; the die holder is arranged on a cover plate, the cover plate is positioned on the base, and the multiple groups of wedges are arranged in a deflection compensation groove of the cover plate along the length direction and are supported on the base; each group of wedge blocks comprises two wedge blocks matched with each other through inclined planes, the inclined planes of the two wedge blocks are matched with each other in a non-planar contact mode, the non-planar contact mode is that the inclined planes are matched and clamped with each other through uneven structures, and the non-planar contact mode comprises but is not limited to zigzag matching, rectangular buckle matching and wave matching, so that the mutually matched tightness of the inclined planes of the two wedge blocks is guaranteed.

In a possible embodiment of the present invention, the inclined plane of the wedge is preferably concave-convex in wave shape.

In a possible embodiment of the present invention, the device further comprises an adjusting block; the adjusting block is arranged on the cover plate, and the die holder is arranged on the adjusting block; the front side face and the rear side face of the upper end of the cover plate are respectively provided with a stop block, a jacking block is arranged between the stop block and the adjusting block on the upper end face of the cover plate, and a jacking screw capable of jacking the jacking block is arranged in the stop block.

In a possible embodiment of the present invention, the cover plate and the base are fixedly connected by a fixing plate.

In a possible embodiment of the present invention, the hole for installing the disc spring is formed on the lower end surface of the base, and the buffer screw passes through the disc spring and then connects the cover plate.

3. Advantageous effects

Compared with the prior art, the beneficial effects of the utility model are that:

(1) the lower die of the utility model is provided with two bending grooves on the side surface, when only one side surface of the lower die is provided with two bending grooves, one bending groove can be selected to bend a workpiece into a corresponding angle according to the thickness of a processed plate under the premise of replacing the lower die; when two bending grooves are formed in the two adjacent side surfaces of the lower die, the distances from the symmetrical center lines of the bending grooves to the symmetrical center lines of the mounting grooves are equal, and the next bending operation can be performed only by turning the lower die by 90 degrees without recalibrating the upper die and the lower die, so that the labor force is reduced, the cost is reduced, and the working efficiency is improved;

(2) the cross section of the lower die of the utility model is a polygon with even number sides, so that the side surface of the lower die, which is provided with the bending groove, is provided with a mounting groove corresponding to the side surface parallel to the bending groove, the cross section of the lower die is preferably rectangular, and the rectangular lower die can be stably placed on a workbench or a mounting table of a bending machine;

(3) the avoidance groove is arranged at the bottom of the bending groove of the lower die, and the bending part of the plate can generate very large stress due to very large stress at the bending part, especially when a thicker plate workpiece is bent, and if the bottom of the bending groove is a sharp groove with a smaller space, the bending part of the plate can extrude with the wall of the sharp groove to generate wave deformation or unevenness or springback of the bending part and the like, so that the quality of the bent workpiece is influenced; the bottom of the bending groove is provided with a certain space avoidance groove which can be used for releasing the stress at the bending position of the workpiece, and the bending position of the workpiece is a normal arc transition angle;

(4) the utility model discloses a lower mould subassembly is equipped with the multiunit voussoir and carries out the deflection compensation to the lower mould, when the work piece of processing is too long (that is the width of bending is too long), both ends angle is up to standard, and the middle bending is too big or undersize, just need carry out the deflection compensation, need jack-up camber upwards through calculating the lower mould promptly, the removal of reuse wedge, the joint point position of wedge and lower voussoir is changed, adjust the whole height of wedge, and then realize the compensation of lower mould deflection deformation, in order to satisfy the shaping requirement of different precision sheet metals, can also further finely tune the compensation to the deflection change that arouses because unpredictable operating mode on the basis of satisfying theoretical work piece bending deflection compensation, greatly improve the bending precision, the bending precision of the work piece of processing has been improved;

(5) the inclined plane matching of each group of wedge blocks in the lower die assembly is non-planar contact matching, and comprises the steps that the inclined plane is concave-convex and wavy, the inclined plane is zigzag or the inclined plane is rectangular buckle matching, so that the fastening matching connection of the upper wedge block and the lower wedge block is ensured, and the planar relative sliding cannot occur, thereby affecting the bending precision;

(6) the lower die component of the utility model is provided with an adjusting block positioned between the die holder and the cover plate and ejector blocks at two sides of the adjusting block, the position of the lower die is correspondingly and transversely adjusted by moving the adjusting block, the thickness of the ejector block is changed, and the ejector block is tightly ejected by an ejecting screw to limit the position of the adjusting block;

(7) the utility model discloses a lower die component is provided with a buffer screw passing through a disc spring on a base, wherein the disc spring adopts a superposition combination, and has good buffer and shock absorption capacity due to the surface friction resistance effect, and the effects of absorbing impact and dissipating energy are obvious; in the combined spring which bears a large load, the size of each disc is not large, which is beneficial to manufacturing and heat treatment, and when some discs are damaged, only individual replacement is needed, thereby being beneficial to maintenance and repair.

Drawings

FIG. 1 is an end view of the lower mold of the present invention;

FIG. 2 is a schematic structural view of a lower mold assembly without a lower mold according to the present invention;

FIG. 3 is a schematic structural view of the die holder of the present invention;

FIG. 4 is a schematic structural view of the cover plate of the present invention;

FIG. 5 is a front view of a set of wedges of the present invention engaged;

FIG. 6 is an enlarged view of a portion of area A of FIG. 2;

fig. 7 is a usage state diagram of the lower mold assembly of the present invention.

In the figure:

1. an upper die; 2. a lower die; 201. a first V-shaped groove; 202. a second V-shaped groove; 203. a third V-shaped groove; 204. a fourth V-shaped groove; 205. an avoidance groove; 206. mounting grooves; 3. a die holder; 4. an installation table; 401. a wear layer; 5. an adjusting block; 6. a top block; 7. a stopper; 701. jacking the screw tightly; 8. a cover plate; 801. a deflection compensation slot; 9. a wedge block; 901. an upper wedge block; 902. a lower wedge block; 10. a fixing plate; 11. a base; 12. a set screw; 13. a buffer screw; 14. a disc spring; 15. and (5) a workpiece.

Detailed Description

For a further understanding of the present invention, reference will be made to the following detailed description taken in conjunction with the accompanying drawings and examples.

Example 1

The lower die for the bending machine of the present embodiment is a rectangular parallelepiped lower die 2, and includes a bending groove and a mounting groove 206.

The lower mold 2 of the present embodiment includes two bending grooves and one mounting groove 206, wherein the distance from the symmetrical center line of the two bending grooves to the symmetrical center line of the mounting groove 206 is L, and L is 13cm in the present embodiment. Specifically, the two bending grooves are formed in the same side face of the lower die 2, the opening angles of the two bending grooves are equal and are 82 degrees, the opening widths of the two bending grooves are different and are respectively 10cm and 16cm, and the two bending grooves can be used for bending plate workpieces with different thicknesses; the mounting groove 206 is formed in the side surface of the lower die 2 opposite to the side surface where the bending groove is formed, and the shape of the mounting groove is matched with that of a mounting table on the bending machine; the other two side surfaces of the lower die 2 are planes and are parallel to each other.

According to the thickness of the plate workpiece, selecting a corresponding proper bending groove as a working groove for the bending operation, when the plate workpieces with other thicknesses need to be bent, horizontally moving the upper die 1 by 26cm leftwards or rightwards, and adjusting and positioning to be aligned with the other bending groove of the lower die 2, namely, to be aligned with the working groove for the bending operation at the moment. Need not change lower mould 2, practice thrift the labour, improve work efficiency.

It is worth to be noted that, according to the requirement of the bending shape in the actual production, when the bending groove shape of the present embodiment is other shapes than the V-shape, such as the arc-shaped bending groove, the rectangular bending groove, etc., all are the expression forms of the present embodiment, and the present invention is within the protection scope of the present invention.

Example 2

As shown in fig. 1, the lower die for a bending machine of the present embodiment is a rectangular parallelepiped lower die 2, and includes a bending groove and an installation groove 206.

The bending groove of this embodiment includes four V-shaped bending grooves, which are a first V-shaped groove 201, a second V-shaped groove 202, a third V-shaped groove 203 and a fourth V-shaped groove 204, respectively, the first V-shaped groove 201 and the second V-shaped groove 202 are opened on one side surface of the lower mold 2, and the side surface of the lower mold 2 adjacent to the side surface is opened with the third V-shaped groove 203 and the fourth V-shaped groove 204. Wherein, the opening angle homogeneous phase of four V-arrangement bending grooves is equal, and this embodiment adopts opening angle to be 82, but its size diverse, the concrete expression is: the opening width of the first V-shaped groove 201 is 20cm, and the corresponding symmetrical center line is d; the opening width of the second V-shaped groove 202 is 5cm, and the corresponding symmetrical center line is c; the opening width of the third V-shaped groove 203 is 16cm, and the corresponding symmetrical center line is c; the opening width of the fourth V-shaped groove 204 is 10cm, and the corresponding symmetrical middle line is j; the bottoms of the four V-shaped bending grooves are provided with square avoiding grooves 205, and the avoiding grooves 205 are used for releasing stress at the bending part of the workpiece 15 to avoid deformation.

The mounting grooves 206 of the present embodiment include two mounting grooves 206 with the same size, which are respectively located on the other two sides of the lower mold 2, and the symmetrical center lines of the two mounting grooves 206 are a and b, respectively, wherein the distances from the symmetrical center line a to the symmetrical center lines c and d are equal to L, the distances from the symmetrical center line b to the symmetrical center lines j and k are equal to L, and L is 13 cm.

In the embodiment, different bending grooves can be selectively replaced according to the thickness of the plate workpiece 15, and when the required bending groove and the bending groove used in the previous bending work are arranged on the same side surface of the lower die 2, the replacement operation is basically the same as that described in embodiment 1; when the required bending groove and the bending groove used in the previous bending operation are opened on different side surfaces of the lower die 2, the lower die 2 is turned by 90 degrees, and the mounting groove 206 is replaced, so that the required bending groove is located at the horizontal working position, and the next bending operation can be performed without repositioning the upper die 1 and the lower die 2 or performing the positioning of the upper die 1 as in embodiment 1.

For example, after the first V-shaped groove 201 is used as a bending work groove, according to the actual production situation, when the next batch of bending workpieces 15 needs to use the third V-shaped groove 203, the lower die 2 is turned clockwise by 90 ° around the center thereof, and the upper die 1 and the lower die 2 are still aligned, so that the bending work of the batch of workpieces 15 can be directly performed; when the next batch of bent workpieces 15 needs to use the fourth V-shaped groove 204, the lower die 2 is turned clockwise by 90 degrees around the center thereof, the upper die 1 is moved to the left by 26cm, the upper die and the lower die are calibrated, and the bending work of the batch of workpieces 15 is started.

It should be noted that the end surface of the lower die 2 of this embodiment can also be made into even-numbered polygons such as hexagon and octagon, and the plate workpieces with different thicknesses can be processed by turning over the lower die 2 according to this embodiment without complicated upper and lower die calibration work. However, since the end surface of the lower die 2 is rectangular, that is, the lower die 2 has a rectangular parallelepiped shape, the lower die 2 is more excellent in mounting stability.

Simultaneously, according to the needs of the shape of bending in the actual production, when the bending groove shape of this embodiment is other shapes outside the V-arrangement, like arc bending groove, rectangle bending groove etc. are the expression form of this embodiment the utility model discloses a within the scope of protection.

Example 3

The lower die assembly for the bending machine of the present embodiment includes a lower die 2, a die holder 3, a cover plate 8, a wedge 9, and a base 11, where the lower die 2 is described in accordance with the lower die 2 in embodiment 2.

Specifically, as shown in fig. 3, the die holder 3 includes an upwardly projecting mounting table 4, and the mounting table 4 is used to mount the lower die 2 in cooperation with the mounting groove 206. Because the lower die 2 in the bending work is subjected to very large bending force, in the actual work, in order to reduce the abrasion between the lower die 2 and the die holder 3 and further cause the instable installation of the lower die 2, a wear-resistant layer 401 is coated on the upper surface of the installation table 4, and the surface of the installation groove 206 is subjected to surface treatment to enhance the wear-resistant performance of the surfaces of the installation table 4 and the installation groove 206, so that the service life of the installation table is prolonged.

A cover plate 8 is arranged below the die holder 3, the structure of the cover plate 8 is shown in fig. 4, a deflection compensation groove 801 is formed in the lower bottom surface of the cover plate 8, a plurality of groups of wedges 9 are placed in the deflection compensation groove 801, each group of wedges 9 comprises an upper wedge 901 and a lower wedge 902, and the inclined surfaces of the upper wedge 901 and the lower wedge 902 are matched in a wavy manner, as shown in fig. 5; the height of a group of wedge blocks is adjusted by changing the relative matching position of the wavy clamping grooves and the buckles on the inclined surfaces of the upper wedge block and the lower wedge block, so that the deflection compensation is carried out on the workpiece 15.

The specific setting process of deflection compensation is as follows:

(1) firstly, placing a workpiece sample to be bent on a workbench of a lower die assembly without a plurality of groups of wedge blocks 9, normally bending the workpiece sample, and taking down the workpiece sample after the bending operation is finished;

(2) measuring the deformation amount of 9 points at equal intervals on the workpiece sample obtained in the step (1), and calculating the required compensation height △ h of the corresponding positions of each group of wedges;

(3) and (3) correspondingly placing each group of wedge blocks in the flexibility compensation groove 801 of the cover plate 8 according to the required compensation height △ h calculated in the step (2) for flexibility compensation.

The base 11 is arranged below the cover plate 8 and used for fixing the cover plate 8, a plurality of holes for mounting disc springs 14 are formed in the lower end face of the base 11, buffer screws 13 are inserted into the disc springs 14, and the buffer screws 13 are inserted into corresponding threaded holes in the lower bottom face of the cover plate 8 and used for fixedly connecting the base 11 and the cover plate 8; the front and back sides of the base 11 and the cover plate 8 are respectively provided with a fixing plate 10, so that the fixed connection between the base 11 and the cover plate 8 is further strengthened.

The base 11 is fixed on the workbench of the bending machine through a fixing screw 12, wherein a threaded hole for installing the fixing screw 12 is formed in the lower bottom surface of the base 11, a notch for placing the fixing screw 12 is formed in the side surface of the base 11, a gasket with an opening can be additionally arranged between the fixing screw 12 and the base 11 as required, and the fastening connection between the base 11 and the workbench of the bending machine is further enhanced.

Example 4

The lower die assembly for a bending machine of the present embodiment is substantially the same as that of embodiment 3, except that: an adjusting block 5 is additionally arranged between the die holder 3 and the cover plate 8 and used for finely adjusting the horizontal position of the lower die 2, as shown in fig. 2 and 7.

The adjusting block 5 is positioned below the die holder 3 and is placed on the cover plate 8, the front side surface and the rear side surface of the upper end of the cover plate 8 are respectively provided with a stop dog 7 through bolts, and the stop dog 7 is provided with a jacking screw 701 which can jack the adjusting block 5 tightly and finely adjust the horizontal position of the adjusting block.

According to the needs of the actual work of bending and the size of regulating block 5, still can set up kicking block 6 between dog 7 and regulating block 5, and tight screw 701 in top pushes up regulating block 5 on acting on kicking block 6, prevents to push up that tight screw 701 direct action has the damage to it on regulating block 5, further strengthens regulating block 5's steadiness simultaneously.

The present invention and its embodiments have been described above schematically, and the description is not limited thereto, and what is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. Therefore, if the person skilled in the art receives the teaching of the present invention, without departing from the inventive spirit of the present invention, the person skilled in the art should also design the similar structural modes and embodiments without creativity to the technical solution, and all shall fall within the protection scope of the present invention.

Claims (10)

1. The utility model provides a lower mould for bending machine, has two bending grooves on its at least one side, its characterized in that: mounting grooves (206) are arranged on the opposite side surfaces of the two bending grooves on the side surface of the lower die (2); the distances from the symmetrical middle lines of the two bending grooves to the symmetrical middle line of the mounting groove (206) are equal.

2. The lower die for a bending machine according to claim 1, characterized in that: the cross section of the lower die (2) is polygonal and is provided with even number of sides.

3. The lower die for a bending machine according to claim 2, wherein: the lower die (2) is in a cuboid shape, bending grooves are formed in two adjacent side faces of the lower die, and mounting grooves (206) are formed in the other two side faces of the lower die.

4. The lower die for a bending machine according to any one of claims 1 or 3, wherein: the bending groove is a V-shaped groove, and the mounting groove (206) is a rectangular groove.

5. The lower die for a bending machine according to claim 4, wherein: and an avoiding groove (205) is formed at the bottom of the bending groove.

6. The utility model provides a bender is with lower mould subassembly which characterized in that: comprising a lower die for a bending machine according to claims 1 to 5, and a die holder (3); the die holder (3) is provided with an installation platform (4) matched with the installation groove (206) of the lower die (2).

7. A lower die assembly for a bending machine according to claim 6, wherein: the device also comprises a cover plate (8), a base (11) and a plurality of groups of wedges (9); the die holder (3) is arranged on a cover plate (8), the cover plate (8) is positioned on a base (11), and a plurality of groups of wedges (9) are arranged in a deflection compensation groove (801) of the cover plate (8) along the length direction and are supported on the base (11); each group of wedge blocks (9) comprises two wedge blocks (9) matched with each other in an inclined plane, and the inclined planes of the two wedge blocks (9) are matched in a non-planar contact way.

8. A lower die assembly for a bending machine according to claim 7, wherein: the inclined plane of the wedge block (9) is concave-convex shaped into a wave shape.

9. A lower die assembly for a bending machine according to claim 7, wherein: also comprises a regulating block (5); the adjusting block (5) is arranged on the cover plate (8), and the die holder (3) is arranged on the adjusting block (5); the front side surface and the rear side surface of the upper end of the cover plate (8) are respectively provided with a stop block (7), an ejector block (6) is arranged between the stop block (7) and the adjusting block (5) on the upper end surface of the cover plate (8), and an ejection screw (701) capable of ejecting the ejector block (6) tightly is arranged in the stop block (7).

10. A lower die assembly for a bending machine according to any one of claims 7 to 9, wherein: the lower end face of the base (11) is provided with a hole provided with a disc spring (14), and the buffering screw (13) penetrates through the disc spring (14) and then is connected with the cover plate (8).

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