JP2024111531A - Bending machine - Google Patents

Abstract

[Problem] To provide a press brake with a structure that is not easily affected by thrust loads. [Solution] The press brake 1 includes a lower table 5, an upper table 7 supported so as to be movable in the vertical direction, a ball screw mechanism 55 that converts the rotational motion of a rotationally driven output part into linear motion along the vertical direction and outputs the motion, a connection block 60 that connects the ball screw mechanism 55 and the upper table 7, a roller guide 4 that is fixed to a side plate 2 so as to face the connection block 60 in the front-rear direction and extends in the vertical direction, and a pair of linear guide parts 63 that are respectively attached to the connection block 60 and are arranged opposite to each other so as to sandwich the left and right side surfaces of the roller guide 4. Between the roller guide 4 and the connection block 60, a gap Gp is provided that separates the roller guide 4 and the connection block 60 in the front-rear direction. [Selected Figure] Figure 1

Description

The present invention relates to a bending machine.

A press brake is known as one type of bending machine. A press brake bends a workpiece by moving a movable table, on which dies such as punches are attached, up and down relative to a fixed table, on which dies such as dies are attached. A known method of driving the movable table is to use an electric motor such as a servo motor.

Patent document 1 discloses a technology in which a servo motor rotates a ball screw mechanism to move a movable table connected to the ball screw mechanism in the vertical direction.

Chinese Patent Publication No. 112692113

Press brakes are equipped with a linear guide mechanism that guides the vertical movement of the movable table. However, depending on the type of bending process, such as hemming, a thrust load in the forward and backward directions acts on the movable table. The effects of this thrust load also extend to the linear guide mechanism. Requiring a high allowable load for the linear guide mechanism leads to increased costs and a larger structure. For this reason, a new solution to the effect of thrust loads on the linear guide mechanism is required.

The bending machine according to one aspect of the present invention includes a fixed table supported on the front side of a side plate, a movable table that is disposed vertically opposite the fixed table and supported on the front side of the side plate so as to be movable in the vertical direction, a conversion mechanism that converts the rotational motion of a rotationally driven output section into linear motion along the vertical direction and outputs the motion, a connection section that connects the conversion mechanism and the movable table and moves the movable table vertically by the vertical linear motion of the conversion mechanism, a guide body that is fixed to the side plate so as to face the connection section in the front-rear direction and extends in the vertical direction, and a pair of linear guide sections that are attached to the connection sections and disposed opposite to each other so as to sandwich the left and right side surfaces of the guide body, and a gap is provided between the guide body and the connection section to separate the guide body from the connection section in the front-rear direction.

According to one aspect of the present invention, a gap is provided between the guide body and the connection portion. Even if the connection portion moves rearward due to a thrust load, the connection portion can be prevented from interfering with the guide body. Furthermore, the pair of linear guide portions slide in the front-rear direction relative to the side surface of the guide body, allowing the thrust load acting on the pair of linear guide portions to be released. The pair of linear guide portions can move smoothly in the vertical direction even when subjected to a thrust load.

According to one aspect of the present invention, the movable table can be moved smoothly in the vertical direction. Therefore, this effect can be obtained without using a mechanism with a high allowable load.

FIG. 1 is a cross-sectional view of a main part of a press brake as viewed from above. FIG. 2 is a front view showing the configuration of the press brake. FIG. 3 is an enlarged exploded perspective view showing a main portion of the press brake.

Below, we will explain the bending machine according to this embodiment by using a press brake as an example, with reference to the drawings.

Figure 1 is a cross-sectional view of the main parts of a press brake as seen from above. In this specification, the definitions of directions are left-right, front-rear, and up-down. The left-right and front-rear directions correspond to two directions that are orthogonal to the horizontal direction, and the up-down direction corresponds to the vertical direction. In Figure 1, the front side of the paper corresponds to the upward direction, and the back side of the paper corresponds to the downward direction. These directions are used merely for convenience in explaining the press brake according to this embodiment.

The press brake 1 according to this embodiment includes a lower table 5 supported on the front side of the side plate 2, an upper table 7 arranged vertically opposite the lower table 5 and supported on the front side of the side plate 2 so as to be movable in the vertical direction, a ball screw mechanism 55 that converts the rotational motion of the rotationally driven output part into linear motion along the vertical direction and outputs it, a connection block 60 that connects the ball screw mechanism 55 and the upper table 7 and moves the upper table 7 in the vertical direction by the vertical linear motion of the ball screw mechanism 55, a roller guide 4 that is fixed to the side plate 2 so as to face the connection block 60 in the front-rear direction and extends in the vertical direction, and a pair of linear guide parts 63 that are attached to the connection block 60 and are arranged opposite to each other so as to sandwich the left and right side surfaces of the roller guide 4. Between the roller guide 4 and the connection block 60, a gap Gp is provided that separates the roller guide 4 and the connection block 60 in the front-rear direction.

The press brake 1 will be described in detail below with reference to Figures 1 to 3. Figure 2 is a front view showing the overall configuration of the press brake. Figure 3 is an exploded perspective view showing an enlarged view of the main parts of the press brake.

As shown in FIG. 2, the press brake 1 performs bending processing on a plate-shaped workpiece such as sheet metal by cooperation between an upper tool P such as a punch and a lower tool D such as a die. The press brake 1 includes left and right side plates 2, a lower table 5 which is a fixed table, an upper table 7 which is a movable table, left and right table drive devices 20, and a control device 100.

The left and right side plates 2 are arranged opposite each other and spaced apart in the left-right direction.

The lower table 5 extends in the left-right direction and is supported on the lower front sides of the left and right side plates 2. A lower die holder 6 that detachably holds a lower die D is provided in the left-right direction above the lower table 5. The lower die holder 6 has a holder groove formed in the left-right direction for holding the base (shank) of the lower die D.

The upper table 7 extends in the left-right direction and is supported on the upper front sides of the left and right side plates 2 so as to face the lower table 5. The upper table 7 is configured to be freely movable in the up-down direction relative to the left and right side plates 2.

An upper die holder 8 that detachably holds the upper die P is provided on the lower side of the upper table 7 in the left-right direction. The upper die holder 8 has a holder groove formed in the left-right direction for holding the base (shank) of the upper die P.

The left and right table drive devices 20 are fixed to the upper parts of the left and right side plates 2, respectively. Each table drive device 20 moves the upper table 7 in the vertical direction. The table drive device 20 is mainly composed of an electric motor 25, a reduction gear unit 30, and a ball screw mechanism 55.

The electric motor 25 is, for example, a servo motor, and has an electric motor shaft that rotates around an axis. The reduction gear unit 30 has an output section that reduces the rotation of the electric motor shaft at a predetermined reduction ratio and outputs the reduced rotation. The output section of the reduction gear unit 30 is connected to the ball screw mechanism 55.

The ball screw mechanism 55 is a conversion mechanism that converts the rotational motion of the output part of the reduction gear unit 30 into linear motion, thereby moving the upper table 7 in the vertical direction. The ball screw mechanism 55 includes a ball screw nut 56 and a ball screw shaft 57. The ball screw nut 56 is supported inside the housing of the ball screw mechanism 55 via a bearing part. The ball screw nut 56 is connected to the output part of the reduction gear unit 30, and rotates in accordance with the rotation of the output part. The ball screw shaft 57 is screwed into the ball screw nut 56, and moves in the vertical direction as the ball screw nut 56 rotates forward and backward.

A connection block 60 is connected to the lower end of the ball screw mechanism 55, specifically the lower end of the ball screw shaft 57. A hanging bolt 61 that hangs down in the vertical direction is attached to the lower end of the connection block 60, and the hanging bolt 61 supports a support shaft 62 that passes through the upper table 7 in the front-rear direction. The ball screw shaft 57 is connected to the upper table 7 via the connection block 60, which includes the hanging bolt 61 and the support shaft 62. In other words, the connection block 60 connects the ball screw mechanism 55 and the upper table 7, and moves the upper table 7 in the vertical direction by the vertical linear motion of the ball screw mechanism 55.

A control device 100, such as an NC (Numerical Control) device that controls the operation of the press brake 1, is supported via a connecting arm on the left side plate 2. The control device 100 controls the electric motor 25, the reduction gear unit 30, etc.

In a press brake 1 configured in this way, the workpiece is positioned on the lower die D attached to the lower die holder 6 of the lower table 5. When the upper table 7, on which the upper die P is attached to the upper die holder 8, is lowered toward the lower table 5, the workpiece is pressurized between the upper die P and the lower die D. As a result, the upper die P and the lower die D work together to bend the workpiece at the desired bending angle.

The drive system that drives the upper table 7 will be described below with reference to Figures 1 and 3. In the following explanation, the drive system on the left side will be described, but the drive system on the right side is similar.

As shown in FIG. 3, a roller guide 4 is provided on the front side of the side plate 2. The roller guide 4 is fixed to the side plate 2 so as to face the connection block 60. The roller guide 4 extends in the vertical direction corresponding to the vertical movable range of the connection block 60. The roller guide 4 has a prismatic shape with a rectangular cross section.

A pair of linear guides 63 are attached to the rear side of the connection block 60. The pair of linear guides 63 are arranged opposite each other so as to sandwich the left and right sides of the roller guide 4.

Each linear guide section 63 is composed of a roller follower 63a and a shaft body 63b. The roller follower 63a is a rotating member equipped with a bearing structure such as a follower bearing. The roller follower 63a is rotatably supported by the shaft body 63b so that the outer circumferential surface of the roller follower 63a contacts the side surface of the roller guide 4. The shaft body 63b is attached to the connection block 60 and extends in the front-rear direction. The roller follower 63a is fitted onto the outer periphery of the shaft body 63b.

In this embodiment, the shaft body 63b is configured as an eccentric shaft. The shaft body 63b, which is an eccentric shaft, is provided with an eccentric portion that is eccentric by a predetermined amount radially outward from the rotation axis along the front-rear direction. By rotating the shaft body 63b around the rotation axis, the position of the eccentric portion is offset in the left-right direction. This allows the rotation axis of the roller follower 63a to be offset in the left-right direction.

When the roller follower 63a is assembled to the connection block 60, a gap may occur between the roller follower 63a and the side of the roller guide 4 due to manufacturing errors, dimensional tolerances, etc. In this case, the roller follower 63a can be brought into contact with the side of the roller guide 4 by offsetting the rotation axis of the roller follower 63a in the left-right direction using the shaft body 63b.

As shown in FIG. 1, a gap Gp is provided between the roller guide 4 and the connection block 60, separating the roller guide 4 and the connection block 60 in the front-to-rear direction. This gap Gp is set, for example, in the range of 5 mm to 15 mm. Since the thrust load F, which will be described later, acts more strongly as the pressing force of the press brake 1 increases, it is preferable to set a larger gap Gp for press brakes 1 with higher pressing capacity.

In addition, the roller guide 4 is in contact with a rotatable roller follower 63a. Therefore, the rotation of the roller follower 63a can smoothly guide the movement of the connection block 60 in the vertical direction.

As shown in FIG. 1, a pair of first guide rollers 7a and a pair of second guide rollers 7b are provided on the rear surface of the upper table 7. The pair of second guide rollers 7b are disposed below the pair of first guide rollers 7a. Of the pair of second guide rollers 7b, one of the second guide rollers 7b is not shown in FIG. 1 for convenience of illustration.

A first support plate 3a is attached to the front side of the side plate 2 via a support member 3. The first support plate 3a is arranged parallel to the upper table 7 and extends in the vertical direction. A pair of first guide rollers 7a are arranged opposite each other so as to sandwich the front and rear plate surfaces of the first support plate 3a. Each first guide roller 7a is rotatably supported on a shaft extending in the left-right direction.

A second support plate 3b is attached to the side plate 2. The second support plate 3b is arranged parallel to the upper table 7 and extends in the vertical direction. A pair of second guide rollers 7b are arranged opposite each other so as to sandwich the front and rear plate surfaces of the second support plate 3b. Each second guide roller 7b is rotatably supported by a shaft extending in the left-right direction.

The pair of first guide rollers 7a and the pair of second guide rollers 7b move up and down along the first support plate 3a and the second support plate 3b provided on the side plate 2. The pair of first guide rollers 7a and the pair of second guide rollers 7b are guided by the first support plate 3a and the second support plate 3b, so that the inclination of the upper table 7 moving in the up and down direction can be regulated. In other words, the position of the upper table 7 can be maintained vertically.

In the press brake 1 configured as described above, depending on the type of bending process such as hemming, a thrust load F acts on the upper table 7 in the front-rear direction. At this time, the thrust load F can be received by the first support plate 3a and the second support plate 3b, and the pair of first guide rollers 7a and the pair of second guide rollers 7b. Specifically, the thrust load F is received by the first support plate 3a and the second support plate 3b warping and the pair of first guide rollers 7a and the pair of second guide rollers 7b bending.

In particular, the pair of second guide rollers 7b are located closer to the processing position. Therefore, the thrust load F is received by the second support plate 3b and the pair of second guide rollers 7b.

As described above, a gap Gp is provided between the roller guide 4 and the connection block 60. Therefore, even if the connection block 60 moves rearward due to the thrust load F, the connection block 60 can be prevented from interfering with the roller guide 4. Furthermore, the roller followers 63a move in the front-rear direction so as to slide against the side surface of the roller guide 4, so that the thrust load acting on the pair of linear guide portions 63 can be released. This allows the pair of linear guide portions 63 to move smoothly in the vertical direction even when subjected to a thrust load. Therefore, the above effect can be obtained without using a mechanism with a high allowable load.

In this embodiment, each linear guide section 63 is attached to the connection block 60 and includes a shaft body 63b extending in the front-rear direction, and a roller follower 63a rotatably supported on the shaft body 63b so as to contact the side of the roller guide 4.

With this configuration, the roller follower 63a in contact with the side of the roller guide 4 rotates, allowing the upper table 7 to move smoothly. Because the contact area between the roller follower 63a and the side of the roller guide 4 is small, the roller follower 63a can slide along the side of the roller guide 4. This allows the thrust load acting on the pair of linear guide sections 63 to be effectively released.

Note that although the roller follower 63a is shown as an example of a rotating member, this embodiment is not limited to this. Also, instead of a rotating member such as the roller follower 63a, the linear guide portion 63 may be a pad that comes into surface contact with the side surface of the roller guide 4 and slides on the side surface.

In this embodiment, the shaft body 63b is an eccentric shaft that can offset the rotation axis of the roller follower 63a in the left-right direction.

This configuration makes it possible to fill the gap that occurs between the left and right side surfaces of the roller guide 4 and the pair of linear guide parts 63 when the pair of linear guide parts 63 is assembled. This allows the pair of linear guide parts 63 to come into contact with the left and right side surfaces of the roller guide 4 without any gaps.

In this embodiment, the press brake 1 further includes a pair of second guide rollers 7b that are attached to the upper table 7 and can rotate relative to each other. The pair of second guide rollers 7b are arranged opposite each other so as to sandwich the front and rear plate surfaces of the second support plate 3b that is attached to the side plate 2 in parallel with the upper table 7.

With this configuration, the thrust load acting on the upper table 7 can be received by the pair of second guide rollers 7b and the second support plate 3b. This allows the thrust load to be dispersed, thereby suppressing the thrust load acting on the pair of linear guide parts 63.

As described above, this embodiment has been described, but the description and drawings forming a part of this embodiment should not be understood as limiting this embodiment. Various alternative embodiments, examples, and operating techniques will be apparent to those skilled in the art from this embodiment.

REFERENCE SIGNS LIST 1 Press brake 2 Side plate 3 Support member 3a First support plate 3b Second support plate 4 Roller guide 5 Lower table (fixed table)
6 Lower die holder 7 Upper table (movable table)
7a First guide roller 7b Second guide roller 8 Upper die holder 20 Table drive device 25 Electric motor 30 Speed reducer unit 55 Ball screw mechanism (conversion mechanism)
60 Connection block (connection part)
63 Linear guide portion 63a Roller follower 63b Shaft body (eccentric shaft)
100 Control device

Claims (4)

a fixed table supported on a front side of the side plate;
a movable table disposed opposite to the fixed table in the vertical direction and supported on the front side of the side plate so as to be movable in the vertical direction;
a conversion mechanism that converts the rotational motion of the rotationally driven output section into linear motion along an up-down direction and outputs the linear motion;
a connection part that connects the conversion mechanism and the movable table and moves the movable table in the vertical direction by the vertical linear motion of the conversion mechanism;
a guide body that is fixed to the side plate so as to face the connection portion in the front-rear direction and extends in the up-down direction;
a pair of linear guide parts attached to the connection parts, respectively, and arranged opposite to each other so as to sandwich the left and right side surfaces of the guide body;
A gap is provided between the guide body and the connection portion to separate the guide body and the connection portion in the front-rear direction. Each of the linear guide portions is
A shaft body attached to the connection portion and extending in the front-rear direction;
The bending machine according to claim 1 , further comprising: a rotating member rotatably supported by the shaft body so as to contact a side surface of the guide body. The shaft body is
3. The bending machine according to claim 2, wherein the rotation axis of the rotating member is an eccentric axis that can be offset in the left-right direction. A pair of guide rollers attached to the movable table and rotatable relative to each other are further provided,
The pair of guide rollers are
4. The bending machine according to claim 1, wherein a support plate is attached to the side plate in parallel with the movable table, and the support plate is disposed opposite the movable table so as to sandwich front and rear plate surfaces of the support plate therebetween.

Images