JP2000126899A - Screw press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent seizure and also to equalize the load allovcation to each screw thread of a nut. SOLUTION: A flywheel 12 is forward rotated by a flywheel mechanism 100, this forward rotational force is transmitted to a screw shaft 1 and, when the screw shaft 1 is forward rotated, the nut 3 which is fit to the screw shaft 1 is lowered. Thus, a die 7 is lowered toward a die 9 and press working is performed. When the press working is completed, the nut 3 is elevated by oppositely rotating the screw shaft 1 by a screw reversing mechanism 200. The nut 3 is divided into two by being cut in the radious direction in the middle part in the axial direction. Thus, deffects at the time of casting the nut 3 are reduced, the accuracy of thread cutting is improved and seizure is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw-type press machine, which is designed to prevent seizure between a screw shaft and a nut and to level the load shared by each thread of the nut. is there.

[0002]

2. Description of the Related Art As a large press machine for forging, there is a screw press machine. In this screw-type press machine, a nut is screwed onto a rotatable screw shaft. The rotation of the nut is restricted, and the nut is slidably arranged vertically along the screw shaft along with the rotation of the screw shaft. For this reason, the nut descends along the screw shaft when the screw shaft rotates forward, and rises along the screw shaft when the screw shaft rotates reversely. The upper mold is attached to the nut via a nut outer cylinder, a ram, an upper die holder, and the like. A lower mold is arranged below the upper mold.

The flywheel is rotated by a flywheel drive mechanism. When the rotational force of the flywheel is transmitted to the screw shaft and the screw shaft is rotated forward, the nut descends and the upper mold is moved. Forging can be performed by descending toward the lower mold and pressing the work between the upper and lower molds.

[0004] When the upper mold reaches the bottom dead center and press working is completed, the screw shaft is rotated reversely by the screw shaft reversing mechanism. The reverse rotation of the screw shaft raises the nut and the upper mold.

[0005]

The inventor of the present invention has designed and manufactured an ultra-large screw press machine. In such an ultra-large screw type press machine, when a work is pressed, an extremely large sliding contact force acts between the screw shaft and the nut. It has been found that consideration must be given to leveling the shared load of each thread. In a conventional screw-type press machine, a large sliding contact force is not generated, so there was no need to devise such a viewpoint.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a screw-type press machine capable of preventing seizure between a screw shaft and a nut and leveling a shared load of each thread of the nut. And

[0007]

According to the present invention, there is provided a screw shaft having a screw formed on a peripheral surface thereof, the screw shaft being rotatably erected, and being screwed to the screw of the screw shaft. A nut that descends along the screw shaft when the screw shaft rotates forward and rises along the screw shaft when the screw shaft rotates reversely; and a nut that rotates forward around the screw shaft around the screw shaft. A flywheel that transmits torque to the screw shaft until the nut descends from the top dead center to the bottom dead center; and, when the nut reaches the bottom dead center, the screw shaft is rotated in reverse to rotate the nut. In the screw press machine having a screw shaft reversing mechanism for raising the screw to the top dead center, the nut is at least one position along the axial direction, Is cut in the radial direction, characterized in that it is divided into a plurality.

[0008] Further, according to the structure of the present invention, a screw shaft is formed on a peripheral surface of the screw shaft, the screw shaft is rotatably erected, and is screwed to the screw of the screw shaft. A nut that descends along a shaft and rises along the screw shaft when the screw shaft rotates in reverse, a nut outer cylinder fixed to the nut while wrapping the nut from the outer periphery, and a screw around the screw shaft A flywheel that is located on the outer peripheral side of the shaft and rotates forward, transmitting a rotational force to the screw shaft until the nut falls from the top dead center to the bottom dead center, and when the nut reaches the bottom dead center, In a screw press machine having a screw shaft reversing mechanism that raises the nut to the top dead center by rotating the screw shaft in the reverse direction, the nut and the front The position of the boundary surface between the nut barrel,
A pin hole that extends in the axial direction from the end surface of the nut and the nut outer cylinder and has a diameter that is reduced in a stepwise manner toward the depth direction of the hole is formed, and in each hole having a different diameter of the pin hole,
It is characterized by having a detent structure formed by inserting pins having a diameter corresponding to the diameter of the hole.

[0009] Further, according to the present invention, there is provided a screw shaft formed with a screw formed on a peripheral surface and rotatably erected, and screwed to the screw of the screw shaft. A nut that descends along the shaft and rises along the screw shaft when the screw shaft rotates in the reverse direction, and a nut that is located on the outer peripheral side of the screw shaft around the screw shaft and rotates forward, and the nut moves downward from the top dead center. A flywheel that transmits torque to the screw shaft until it descends to a dead center, and a screw shaft that raises the nut to a top dead center by rotating the screw shaft in reverse when the nut reaches a bottom dead center. In a screw press having an inversion mechanism, the thickness of the teeth of the screw of the screw shaft with respect to the thickness of the teeth of the nut,
It is characterized by being set to 0.7 to 0.85.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<Overview of Screw Press Machine>
First, an overall outline of a screw-type press machine according to an embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the screw shaft 1 is rotatably attached to a press casing 2 and stands upright. A screw 1 a is formed on the lower peripheral surface of the screw shaft 1.

The nut 3 is screwed into the screw 1a of the screw shaft 1. A nut outer cylinder 4 is fixed to the nut 3 so as to wrap the outer peripheral surface of the nut 3, and a ram 5 is fixed to the nut outer cylinder 4.
Has been fixed. The structure of the nut 3 and the nut 3
The details of the detent structure will be described later. Further, details of the screw shape of the screw 1a of the screw shaft 1 and the screw shape of the nut 3 will be described later.

The ram 5 is arranged so as to be slidable vertically along the press casing 2 while the rotation thereof is restricted. Therefore, the rotation of the nut 3 connected to the ram 5 is also restricted, and the nut 3 moves in the vertical direction according to the rotation of the screw shaft 1. That is, the nut 3 descends along the screw shaft 1 when the screw shaft 1 rotates forward, and rises along the screw shaft 1 when the screw shaft 1 rotates reversely.

An upper die holder 6 is provided at a lower end of the ram 5, and an upper die 7 is attached to the upper die holder 6. A lower die holder 8 is provided below the upper mold 7.
Is mounted on the mold 9.

The ram 5 is provided with a bracket 10, and a hydraulic ram balance cylinder 11 is connected to the bracket 10. The ram balance cylinder 11 gives the ram 5 a force that constantly urges the ram 5 upward. This ram balance cylinder 11 is
The ram 5 is constantly urged upward by an oil pressure of about 90% of the weight of the ram 5.

On the other hand, the annular flywheel 12 is rotatably disposed on the press casing 2 so as to be located on the outer peripheral side of the screw shaft 1 around the screw shaft 1. The flywheel 12 receives power from the flywheel drive mechanism 100 via belt transmission and rotates in one direction (forward rotation direction). The flywheel drive mechanism 100 is a drive mechanism using an electric motor as a drive source, and details thereof will be described later.

A clutch disc 13 is fixed to the upper part of the screw shaft 1. A clutch shoe 14 is inserted and arranged at a plurality of positions on the disk surface of the clutch disc 13 in the circumferential direction. A top disk 15 and a bottom disk 16 are arranged with the clutch shoe 14 interposed therebetween. The top disk 15 is urged upward by a spring 17 and the bottom disk 1
6 is fixed to the flywheel 12.

A plunger 18 is arranged on the upper surface of the top disk 15. When pressure oil is supplied to the plunger 18 from above, the plunger 18 moves downward,
The top disk 15 is pushed downward against the spring force of the spring 17. When the top disk 15 is pushed downward in this manner, the clutch shoe 14 is sandwiched between the top disk 15 and the bottom disk 16, and the clutch is turned on. When such a clutch is turned on, the positive rotational force of the flywheel 12 is transmitted to the clutch disc 13 and thus to the screw shaft 1.

When the supply of the pressure oil to the plunger 18 is stopped, the top disk 15 is moved upward by the spring 17 to be separated from the clutch shoe 14 and the clutch is turned off. When the clutch is turned off, the flywheel 1
Transmission of the forward rotation power from 2 to the screw shaft 1 is shut off.

In the screw shaft 1, a brake disk 19 is fixed above the clutch disk 13, and a hydraulic brake 20 is arranged so as to sandwich the brake disk 19. When pressure oil is supplied to the hydraulic brake 20, the hydraulic brake 20 sandwiches the brake disk 19, and the brake can be applied to the rotation of the brake disk 19 and thus the screw shaft 1.

At the top of the screw shaft 1, a screw shaft reversing mechanism 200 is arranged. The screw shaft reversing mechanism 200 is a mechanism using a rack, a pinion, and a hydraulic cylinder, although a detailed structure will be described later. The screw shaft reversing mechanism 200 is a mechanism for rotating the screw shaft 1 in the reverse direction after the die 7 reaches the bottom dead center and the pressing of the work is completed.

Here, the flywheel drive mechanism 100 will be described with reference to FIGS.

As shown in FIGS. 1 and 2, the power (rotational force) of a motor 101, which is a drive source of a flywheel drive mechanism 100, is controlled by a torque converter 1 having a built-in clutch.
02. The power output from the torque converter 102 is transmitted to the bevel reducer 10 via the universal joint 103.
4 is transmitted. The power output from the bevel reducer 104 is transmitted to the pulley device 106 via the universal joint 105. The pulley device 106 has a pulley 106a and a built-in air clutch. The pulley 106a of the pulley device 106 and the flywheel 12
, Three belts 107 are wound around.

Turn on the clutch of the torque converter 102
State, and the air clutch of the pulley device 106 is turned on, and the motor 101 is rotationally driven,
The flywheel 12 can be rotated by applying a rotational force to the flywheel 12 by the belt transmission of the belt 107.

Next, the screw shaft reversing mechanism 200 will be described with reference to FIGS.

As shown in FIGS. 1 and 3, the pinion 201 of the screw shaft reversing mechanism 200 is coaxially fixedly mounted on the top of the screw shaft 1. This pinion 201
, A pair of racks 202a and 202b are screwed. The pair of racks 202a and 202b
1 are interposed therebetween, and are supported by guide rollers R arranged vertically and can move in the horizontal direction.

[0027] Hydraulic cylinders 203a and 203b are connected to the racks 202a and 202b, respectively. The hydraulic oil is constantly supplied to the two hydraulic cylinders 203a and 203b from a hydraulic source 204. Further, an accumulator 205, a check valve 206, and the like are arranged in the hydraulic piping system.

When the large inertial force of the flywheel 12 is not transmitted to the screw shaft 1, the hydraulic cylinders 203a and 203b are extended and the racks 202a and 202 are extended.
b moves forward F, and the pinion 201 rotates in the reverse direction. The screw shaft 1 also rotates reversely by the reverse rotation of the pinion 201.

When the screw shaft 1 rotates forward due to the large inertial force of the flywheel 12 and the pinion 201 rotates forward, the racks 202a and 202b move backward B,
The hydraulic cylinders 203a and 203b contract. That is, since the inertia force of the flywheel 12 is extremely large as compared with the force of the hydraulic cylinders 203a and 203b, the inertia force of the flywheel 12 is large even if the hydraulic oil is constantly supplied to the hydraulic cylinders 203a and 203b. When the screw shaft 1 is rotating forward by force, the hydraulic cylinders 203a and 203b contract.

In the screw shaft reversing mechanism 200 having such a configuration, the screw shaft 1 rotates forward due to the large inertial force of the flywheel 12, and the ram 5 (nut 3) moves from the top dead center to the bottom dead center. In this case, the pinion 201 rotates forward and the leading ends of the racks 202a and 202b move backward B from the ram top dead center position P1 toward the ram bottom dead center position P2. Therefore, the hydraulic cylinders 203a, 203a
03b shrinks. In this case, the hydraulic cylinder 203
Although a and 203b are given a force in the direction of extension by the pressurized oil, they contract due to the large inertial force of the flywheel 12.

When the ram 5 (nut 3) reaches the bottom dead center and press working is completed, the supply of pressure oil to the plunger 18 is stopped, the clutch shoe 14 is turned off, and the flywheel 12 The transmission of the rotational force to the motor is released. Then, the contracted hydraulic cylinders 203a, 203b immediately start to extend, and the racks 202a, 202b immediately move forward F. That is, since the hydraulic cylinders 203a and 203b are always given a force in the direction of extension by the pressurized oil, if the large inertial force by the flywheel 12 is no longer transmitted, the hydraulic cylinders 203a and 203b immediately extend and the rack 202a , 202b move forward F immediately.

As the racks 202a and 202b move forward, the pinion 201 rotates in the reverse direction, and this pinion 20
By the reverse rotation of 1, the screw shaft 1 also rotates in the reverse direction. When the screw shaft 1 rotates in the reverse direction, the nut 3 (including the ram 5) rises. When the ram 5 (nut 3) reaches the top dead center and the tips of the racks 202a and 202b reach the ram top dead center position P1, the screw shaft 1 is operated by the hydraulic brake.
Is stopped, and the forward movement F of the racks 202a and 202b is stopped.

Next, an outline of the entire press operation of the screw press machine having the above configuration will be described. The flywheel 12 is driven by the flywheel drive mechanism 100.
Is rotated at a specified speed in the forward rotation direction. In this state, pressurized oil is supplied to the plunger 18 and the top disk 15 and the bottom disk 16 sandwich the clutch shoe 14 to turn the clutch ON. Then, the positive rotation force of the flywheel 12 is transmitted to the screw shaft 1, and the screw shaft 1 rotates forward.

When the screw shaft 1 rotates forward, the nut 3
Descends. That is, the upper mold 7 connected to the nut 3 descends toward the lower mold 9. When the mold 7 reaches the bottom dead center, the work set between the mold 7 and the mold 9 is pressed.

It should be noted that the ram balance cylinder 11 is
Is always urged upward, but compared to the force of pressing the nut 3 downward due to the inertial force of the flywheel 12,
Since the force of the ram balance cylinder 11 is extremely small, the lowering of the nut 3 is performed smoothly.

When the mold 7 reaches the bottom dead center, that is, when the press working is completed, the forward rotation speed of the screw shaft 1 is rapidly reduced, whereas the forward rotation speed of the flywheel 12 is substantially the specified speed. As a result, slippage occurs between the clutch shoe 14 and the upper and lower discs 15 and 16. By detecting the occurrence of the slip with the slip sensor, it is detected that the mold 7 has reached the bottom dead center, that is, that the press working has been completed.

When the mold 7 reaches the bottom dead center, that is, when it is detected that the press working is completed, the plunger 18
The supply of the pressure oil to the clutch shoe 14 is stopped, and the clutch shoe 14 is turned off. When the mold 7 reaches the bottom dead center,
That is, at the time when the press working is completed, the press casing 2 is in a state in which the press casing 2 is maximally extended in the vertical direction by the downward force of the ram 5. Therefore, when the clutch shoe 14 is set to the clutch OFF state, a force for contracting the extended press casing 2 and an upward urging force of the ram balance cylinder 11 are applied to the ram 5 and the nut 3. At this point, the screw shaft 1 is reversely rotated by the screw shaft reversing mechanism 200.

Thus, the screw shaft 1 rotates in the reverse direction, and the nut 3 (the ram 5, the mold 7, and the like) moves upward. In this case, the force of the extended press casing 2 to shrink and the upward urging force of the ram balance cylinder 11 are applied to the ram 5 and the nut 3, and the upward movement of the nut 3 is performed smoothly. When the nut 3 moves upward, the screw shaft 1 is braked by the hydraulic brake 20 so that the nut 3 stops at the upper limit position.

When the press working is performed again, the above operation is performed with the clutch shoe 14 in the clutch ON state in the same manner as described above.

By performing such an operation a plurality of times, continuous forging can be performed on the work.

<Description of Nut Structure and Nut Detent Structure> Next, the structure of the nut 3 and the detent structure of the nut 3 will be described with reference to FIGS.

As shown in FIGS. 4 and 5, the nut 3 is
At the central part along the axial direction, it is cut in the radial direction and divided into two parts. Conversely, the upper nut 3a and the lower nut 3b are connected side by side in the axial direction to form one nut 3. In FIGS. 4 and 5, 3
c indicates a dividing line of the nut 3.

A screw is formed on the outer peripheral surface of the nut 3 (3a, 3b), and a screw is also formed on the inner peripheral surface of the nut outer cylinder 4. The nut 3 (3a, 3b) is It is screwed into the inner peripheral surface of the cylinder 4. And, on the boundary surface between the nut 3 and the nut outer cylinder 4, a detent structure 3 using a pin is provided.
00 is attached to restrict the relative rotation between the nut 3 and the nut outer cylinder 4. This detent structure 300
Are mounted to extend from the end faces of the nut 3 and the nut outer cylinder 4 in the axial direction, and are mounted at a plurality of locations on the boundary surface which is annular when viewed from the end face side. The details of the detent structure 300 will be described later.

A ram 5 is fixed to the outer peripheral surface of the nut outer cylinder 4. A detent structure 400 using pins is attached to a boundary surface between the nut outer cylinder 4 and the ram 5 to restrain relative rotation between the nut outer cylinder 4 and the ram 5.

Here, the procedure for manufacturing the nut 3 will be described.
First, a cylindrical member made of brass is formed, and a screw is cut on the outer peripheral surface of the cylindrical member. Two cylindrical members made of brass whose outer peripheral surface is threaded are screwed into the inner peripheral surface of the nut outer cylinder 4, and the rotation preventing structure 300 is attached to restrict rotation. Then, screws are formed on the inner peripheral surfaces of the two cylindrical members connected to the nut outer cylinder 4 by the rotation preventing structure 300. Thus, the nut 3 (3a,
3b) is produced.

As described above, since the nut 3 has the divided structure and the cylindrical members serving as the nuts 3a and 3b are individually cast and lightened, the probability of occurrence of casting defects is reduced and the life of the nut 3 is extended. .

Next, the detent structure 300 for the nut 3 will be described with reference to FIGS.

As shown in FIGS. 5 and 6, a nut outer cylinder 4 is fixed to the nut 3 while wrapping the nut 3 from the outer peripheral side. In the rotation preventing structure 300, a pin hole 301 is formed in a boundary surface between the nut 3 and the nut outer cylinder 4, and a pin 302 is inserted into the pin hole 301. Pin hole 301
Are three pin holes 301a and 301 whose diameters are reduced in a step-like manner in the depth direction of the pin holes 301.
b, 301c are communicated. Three pins 302a, 302b, 302c of the pin 302
Are arranged in the vertical direction (the depth direction of the pin holes),
1 are inserted into the three pin holes 301a, 301b, 301c, respectively. That is, the small diameter pin 302c is inserted into the small diameter pin hole 301c, and the medium diameter pin hole 301b is inserted.
A medium-diameter pin 302c is inserted into the
A large-diameter pin 302a is inserted into 1a.

Here, a method of forming the pin holes 301 will be described with reference to FIG. First, as shown in FIG. 7A, a large-diameter pin hole 301a is formed by a large-diameter drill. Next, as shown in FIG.
Guide bush GB1 is inserted into the inside. Next, FIG.
As shown in (c), a medium-diameter pin hole 301b is formed by a medium-diameter drill through the guide bush GB1. Next, as shown in FIG. 7D, the guide bush GB2 is inserted into the pin hole 301b. Next, as shown in FIG. 7E, a small-diameter pin hole 301c is formed by a small-diameter drill through the guide bushes GB1 and GB2. Then, the pin holes 301 are formed by taking out the guide bushes GB1 and GB2.

In this detent structure 300, each pin 30
Since the pins 2a, 302b, and 302c are continuous, the pin 302 as a whole has a small diameter but is long in the axial direction. For this reason, it is not necessary to use a large pin having a large diameter, and as a result, the nut 3 and the nut outer cylinder 4 can be made thin to sufficiently restrain relative rotation.

A small diameter pin 302c is inserted into the small diameter pin hole 301c, a medium diameter pin 302b is inserted into the medium diameter pin hole 301b, and a large diameter pin 302a is inserted into the large diameter pin hole 301a. Is inserted, even if the mutual centers of the pin holes 301a, 301b, 301c are misaligned, the pins 302a, 302b,
Since the core of 302c is also displaced, each of the pins 302a, 302
b and 302c are the pin holes 301a, 301b and 301c, respectively.
Is inserted without gap. Therefore, the torque transmitted between the nut 3 and the nut outer cylinder 4 can be transmitted reliably.

The torque transmitted from the nut outer cylinder 4 to the nut 3 and acting in the rotational direction (circumferential direction) is
From the central portion in the axial direction to both end portions. For this reason,
The torque acting in the rotational direction is first transmitted via a small diameter pin 302c near the center.

If an extremely large torque in the rotating direction is generated for some reason and the small-diameter pin 302c yields (deforms beyond the elastic limit), the torque distribution changes from the initial state, and the medium-diameter pin 302b The torque is transmitted via. Further, if an extremely large torque in the rotating direction is generated for some reason and the medium-diameter pin 302b yields (deforms beyond the elastic limit), the torque is transmitted through the large-diameter pin 302a.

With this configuration, even if a large torque acts, the torque can be transmitted elastically by the pins 302c, 302b, and 302a. The whole is nut 3
You will no longer dig into it. That is, for example, the pin 302
c yields and the torque distribution changes, so that a large torque is applied to the large-diameter pin, the small-diameter pin does not bite, and the torque is elastically transmitted by the other pins.

If a single pin is used, if a part of the pin yields, the yielded portion spreads out sequentially and the whole pin bites into the nut 3, so that the nut 3 needs to be replaced. It will be difficult.

<Description of Screw Shape of Nut and Screw Shape of Screw Shaft> Next, regarding the screw shape of the nut 3 and the shape of the screw 1a of the screw shaft 1, the engaging portion between the screw shaft 1 and the nut 3 is enlarged. This will be described with reference to FIG.

The screw shapes of the screw shaft 1 and the nut 3 shown in FIG. 8 have been developed for use in an ultra-large screw press machine. The screw shaft 1 is made of NiCrMo steel which has high toughness and is hardly deformed, and the nut 3 is made of brass which has low elasticity and is easily deformed.

The tooth thickness (axial length) H1 of the screw 1a of the screw shaft 1 with respect to the tooth thickness (axial length) H3 of the nut 3, that is, the ratio (H1 / H3),
It is set to 0.7 to 0.85. By the way, in a conventional (not super-large) screw press machine, the ratio (H1 / H
3) was simply set to 1.

In a normal state, the screw shaft 1 and the nut 3 are in contact with each other with the position S1 being a pitch circle diagram. In the nut 3, the length L1 from the screw bottom to the position S1 in the radial direction is made longer than the length L2 from the position S1 to the screw tip to improve the strength of the screw teeth of the nut 3. .

Further, the radius of curvature of the boundary portion 3R between the male screw (thread convex portion) and the female screw (thread concave portion) of the nut 3 is increased to prevent stress concentration on the boundary portion 3R.

If a larger force than usual is applied from the screw shaft 1 to the nut 3, the screw teeth of the nut 3 bend downward and the screw teeth of the screw shaft 1 bend upward. .

When such bending occurs, the contact center position between the screw shaft 1 and the nut 3 moves from S1 to, for example, S2, but the ratio (H1 / H3) is 0.7 to 0.85.
And the length L1 from the screw bottom to the position S1 is
The length from the position S1 to the screw tip is longer than the length L2, and the radius of curvature of the boundary portion 3R is increased.
In order to prevent stress concentration on R, despite the difference in elasticity between the screw shaft 1 and the nut 3,
The upward bending angle of the screw shaft 1 and the downward bending angle of the nut 3 become equal.

Therefore, the screw shaft 1 and the nut 3
, The parallelism between the surface of the screw teeth of the screw shaft 1 and the surface of the screw teeth of the nut 3 is substantially the same as in the normal case. . For this reason, even when a force larger than usual is applied, the oil film (squeeze oil film) supplied between the screw shaft 1 and the nut 3 does not break, and the screw shaft 1
And the nut 3 can be prevented from burning.

If a greater force than the above is applied and the parallelism between the screw tooth surface of the screw shaft 1 and the screw tooth surface of the nut 3 is lost, a squeeze oil film flows out and the screw The shaft 1 and the nut 3 may be seized.

When a larger force than usual is applied from the screw shaft 1 to the nut 3, the nut 3
Of the screw teeth, the screw teeth with concentrated force bend downward,
The force is dispersed to other screw teeth by the amount of bending, and there is also an effect of equalizing the force as a whole.

[0066]

As described above in detail with the embodiments, according to the present invention, a screw shaft is formed on the peripheral surface and is rotatably erected, and is screwed to the screw of the screw shaft. A nut that descends along the screw shaft when the screw shaft rotates forward and rises along the screw shaft when the screw shaft rotates reversely, and is located on the outer peripheral side of the screw shaft around the screw shaft. By rotating forward, the flywheel transmitting torque to the screw shaft until the nut descends from top dead center to bottom dead center, and when the nut reaches bottom dead center, by reversely rotating the screw shaft, In a screw press machine having a screw shaft reversing mechanism for raising the nut to the top dead center, the nut is provided at least at one position along the axial direction. There have, is cut in the radial direction, it has a structure that is divided into a plurality.

Since the nut has a divided structure as described above,
The probability of occurrence of casting defects is reduced, and the processing accuracy of the nut screw is improved. Therefore, the occurrence of seizure with the screw shaft is prevented, and the life of the nut is extended.

Further, in the present invention, a screw shaft is formed on a peripheral surface and is rotatably erected, and is screwed to the screw of the screw shaft. When the screw shaft rotates forward, the screw shaft is rotated. A nut that descends along and rises along the screw shaft when the screw shaft rotates in reverse, a nut outer cylinder fixed to the nut while wrapping the nut from the outer peripheral side, and a screw shaft around the screw shaft. A flywheel that is located on the outer peripheral side and rotates forward, transmitting a rotational force to the screw shaft until the nut descends from the top dead center to the bottom dead center, and when the nut reaches the bottom dead center, the screw shaft A screw-type press machine having a screw shaft reversing mechanism that raises the nut to the top dead center by rotating the nut reversely,
A pin hole is formed at a boundary surface between the nut and the nut outer cylinder, the pin hole extending in the axial direction from the end surface of the nut and the nut outer cylinder, and further, the diameter decreases stepwise toward the depth direction of the hole. Then, a pin with a diameter corresponding to the diameter of the pin hole is inserted into each of the pin holes having different diameters, and a detent structure is provided.

With such a configuration, the pin as a whole has a small diameter but is long in the axial direction, and the nut and the nut outer cylinder can have a thin structure. Further, each nut hole and each pin are elastically in close contact with each other, so that torque can be transmitted reliably.

Further, in the present invention, a screw shaft formed with a screw formed on the peripheral surface and rotatably erected, is screwed to the screw of the screw shaft, and when the screw shaft rotates forward, the screw shaft becomes A nut that descends along and rises along the screw shaft when the screw shaft rotates in the reverse direction, and the nut is positioned on the outer peripheral side of the screw shaft around the screw shaft and rotates forward, and the nut is moved from top dead center to bottom dead center. A flywheel that transmits torque to the screw shaft until the screw shaft descends, and a screw shaft reversing mechanism that raises the nut to the top dead center by rotating the screw shaft in reverse when the nut reaches the bottom dead center. And the thickness of the screw teeth of the screw shaft with respect to the thickness of the teeth of the nut is set to 0.
7 to 0.85.

With this configuration, even when a larger force than usual is applied from the screw shaft toward the nut, the parallelism between the screw tooth surface of the screw shaft and the screw tooth surface of the nut is: It is almost the same as usual.
For this reason, even when a force larger than usual is applied, the oil film (squeeze oil film) supplied between the screw shaft and the nut is not broken, and seizure between the screw shaft and the nut is prevented. be able to.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a screw-type press machine.

FIG. 2 is a configuration diagram showing a flywheel drive mechanism.

FIG. 3 is a configuration diagram showing a screw shaft reversing mechanism.

FIG. 4 is a partially broken perspective view showing a nut and a nut outer cylinder.

FIG. 5 is a sectional view showing a nut and a nut outer cylinder.

FIG. 6 is a cross-sectional view showing a rotation preventing structure.

FIG. 7 is an explanatory view showing a procedure for forming a pin hole.

FIG. 8 is an enlarged configuration diagram showing an occlusion portion between a screw shaft and a nut.

[Explanation of symbols]

 Reference Signs List 1 screw shaft 1a screw 2 press casing 3, 3a, 3b nut 3c dividing line 4 nut outer cylinder 5 ram 6 upper die holder 7 mold 8 lower die holder 9 mold 10 bracket 11 ram balance cylinder 12 flywheel 13 clutch disc 14 Clutch shoe 15 Top disc 16 Bottom disc 17 Spring 18 Plunger 19 Brake disc 20 Hydraulic brake 100 Flywheel drive mechanism 101 Motor 102 Torque converter 103 Universal joint 104 Bevel reducer 105 Universal joint 106 Pulley device 106a Pulley 200 Screw axis reversing mechanism 201 Pinion 202a, 202b Racks 203a, 203b Hydraulic cylinder 204 Hydraulic source 205 Accumulator 206 Check valve 300 Non-rotating structure 3 01, 301a, 301b, 301c Pin hole 302, 302a, 302b, 302c Pin 400 Detent pin

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Minoru Hirota 2-1-1 Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Works, Mitsubishi Heavy Industries, Ltd. No. 6-22, Mitsubishi Heavy Industries, Ltd.Hiroshima Plant 2-chome 8-19 Takashi Engineering Co., Ltd. F-term (reference) 4E090 AA01 AB01 BA02 BB01 BB03 CC04 CC10 HA05

Claims (3)

[Claims] A screw shaft having a screw formed on a peripheral surface thereof, the screw shaft being rotatably erected, being screwed with the screw of the screw shaft, and descending along the screw shaft when the screw shaft rotates forward. A nut that rises along the screw shaft when the screw shaft rotates in the reverse direction; and a nut that is positioned on the outer peripheral side of the screw shaft around the screw shaft and rotates forward, and the nut descends from top dead center to bottom dead center. A flywheel that transmits torque to the screw shaft, and a screw shaft reversing mechanism that raises the nut to top dead center by rotating the screw shaft in reverse when the nut reaches the bottom dead center. In the screw press machine, the nut is cut in a radial direction at at least one location along an axial direction and is divided into a plurality of pieces. Screw press machine, characterized. 2. A screw shaft having a screw formed on its peripheral surface and rotatably erected, and screwed to the screw of the screw shaft, and descends along the screw shaft when the screw shaft rotates forward. A nut that rises along the screw shaft when the screw shaft rotates in the reverse direction, a nut outer cylinder fixed to the nut while wrapping the nut from the outer peripheral side, and an outer peripheral side of the screw shaft around the screw shaft. A flywheel that is positioned and rotates forward, transmitting torque to the screw shaft until the nut descends from top dead center to bottom dead center; and, when the nut reaches bottom dead center, reversely rotates the screw shaft. A screw-type press machine having a screw shaft reversing mechanism for raising the nut to the top dead center by causing the nut and the nut outer cylinder to At the position of the interface, a pin hole that extends in the axial direction from the end surface of the nut and the nut outer cylinder and has a diameter that decreases stepwise as it goes in the depth direction of the hole is drilled. A screw-type press machine comprising a detent structure in which a pin having a diameter corresponding to the diameter of the hole is inserted into the hole. 3. A screw shaft having a screw formed on a peripheral surface thereof, the screw shaft being rotatably erected, being screwed with the screw of the screw shaft, and descending along the screw shaft when the screw shaft rotates forward. A nut that rises along the screw shaft when the screw shaft rotates in the reverse direction; and a nut that is positioned on the outer peripheral side of the screw shaft around the screw shaft and rotates forward, and the nut descends from top dead center to bottom dead center. A flywheel that transmits torque to the screw shaft, and a screw shaft reversing mechanism that raises the nut to top dead center by rotating the screw shaft in reverse when the nut reaches the bottom dead center. In the screw press machine, the thickness of the screw teeth of the screw shaft with respect to the thickness of the nut teeth is set to 0.7 to 0.85. Screw-type press machine that.