JP2001205495A - Crank press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact crank press capable of reducing brake capacity. SOLUTION: This crank press for transmitting the driving power of an electric motor 9 through a clutch 7 to a crank shaft 1, lowering a slide 3, decelerating the elevation of the slide 3 by a brake 6 connected to the crank shaft 1 and stopping the slide 3 at a top dead center in each cycle is composed of a hydraulic pump motor 10 connected through a gear to the crank shaft 1, an accumulator 13 connected to the hydraulic pump motor 10 by hydraulic circuits (a), b and c, first and second switch valves SV3 and SV4 for switching an energy absorbing state for sending hydraulic oil through the hydraulic pump motor 10 to the accumulator 13 and the state of returning the hydraulic oil to a tank and an oil path d for operating the clutch 7 from the accumulator 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a crank press. More specifically, the present invention relates to a crank press used for forging or sheet metal working.

[0002]

2. Description of the Related Art FIG. 4 is a basic structural view of a crank press. The crankshaft 1 is rotated by an electric motor or the like, and a slide 3 is connected to the crankshaft 1 via a connecting rod 2. An upper mold is attached to the lower surface of the slide 3, and a material is put between the upper mold and a lower mold on a bed (not shown).
By lowering the slide 3, the material is forged or formed. Also, slide 3
The piston rod 4a of the balance cylinder 4 is connected,
The compressed air of the accumulator 5 is supplied to the cylinder 4b of the balance cylinder 4, so that the slide 3 is always pulled up. Then, in this state, the crankshaft 1 is driven and rotated, and the slide 3 is moved downward via the connecting rod 2.

In a general-purpose hot forging crank press, an operation method of stopping at a top dead center in each cycle is adopted. In order to enable such an operation, a conventional crank press is shown in FIG. The configuration is taken. A brake 6 is connected to one end of the crankshaft 1, and the brake 6 is switched between an active state and a non-active state by pneumatic pressure via a brake control valve SV1. A clutch 7 and a flywheel 8 are connected to the other end of the crankshaft 1, and the flywheel 8 is rotated by an electric motor 9 via a belt or the like. The clutch 7 is switched between the connected state and the disconnected state by pneumatic pressure by the clutch control valve SV2.

The operation of the crank press will be described with reference to FIG. Now, when the slide 3 is stopped at the top dead center and a press start command is issued, the brake control valve
When the brake 6 is released by the SV1 and the clutch 7 is connected by the clutch control valve SV2, the crankshaft 1 is rotated by the power of the electric motor 9, and the slide 3 starts to descend. When the slide 3 reaches the bottom dead center, the clutch 7 is disconnected by the clutch control valve SV2, and the slide 3 rises due to inertia. While the slide 3 is being lifted, the brake 6 is applied by the brake control valve SV1, and the slide 3 stops at the top dead center and remains stopped until the start of the next stroke. By repeating the above operation, the press operation of stopping once at the top dead center in each cycle is continuously performed.

[0005]

However, in the above-described conventional crank press, when the slide 3 is stopped at the top dead center, the lifting force of the balance cylinder 4 instantaneously absorbs the added large energy and stops. Therefore, a large-capacity brake 6 is required, and the installation of a large-capacity compressor and an air tank to secure an air source necessary for engaging and disengaging the clutch, and noise caused by exhaust when the clutch operates. There was a problem that it became large.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a crank press which can reduce the load on a brake, eliminate the need for installing a large capacity air tank, and reduce the exhaust noise.

[0007]

According to a first aspect of the present invention, there is provided a crank press in which power of an electric motor is transmitted to a crankshaft via a clutch to lower a slide, and a brake connected to the crankshaft slows down the slide. In each cycle, a crank press for stopping the slide at the top dead center, provided with energy absorbing means for converting a part of the kinetic energy at the time of slide ascending into hydraulic energy and absorbing the energy,
An operating circuit of the clutch is connected to a hydraulic circuit constituting the energy absorbing means. The crank press according to claim 2 is the invention according to claim 1,
The energy absorbing means is connected to a gear that rotates with the crankshaft, and receives a rotational force from the crankshaft, a hydraulic pump / motor, an accumulator connected to the hydraulic pump / motor via a hydraulic circuit, and hydraulic fluid. It is characterized by comprising switching means for switching between a state of absorbing energy sent to the accumulator via a hydraulic pump / motor and a state of returning hydraulic oil to the tank. The crank press according to claim 3 is the invention according to claim 1,
The energy absorbing means switches between an accumulator connected to the opposite rod side chamber of the balance cylinder incorporated in the crank press by a hydraulic circuit, an energy absorbing state for sending hydraulic oil to the accumulator, and a state for returning hydraulic oil to the tank. Means.

According to the first aspect of the present invention, kinetic energy is consumed by converting the kinetic energy at the time of ascending the slide to hydraulic energy and storing it, so that the capacity of the brake for stopping the slide can be reduced. Since the hydraulic oil for the clutch is taken from the hydraulic circuit of the energy absorbing means, a large-capacity compressor and air tank for operating the clutch is not required, and no exhaust noise is generated. According to the second aspect of the present invention, the crankshaft and the hydraulic pump / motor are connected by a gear so that torque can be transmitted.
When the slide is raised, the hydraulic pump / motor functions as a pump to accumulate hydraulic oil in the accumulator and convert kinetic energy into hydraulic energy, so that the brake capacity can be reduced. According to the third aspect of the present invention, the balance cylinder functions as a pump when the slide is lifted, hydraulic fluid can be stored in the accumulator, and kinetic energy can be converted into hydraulic energy, so that the brake capacity can be reduced. Further, since the cylinder is used as the energy absorbing means, the operation efficiency is improved as compared with the hydraulic pump / motor.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a hydraulic circuit diagram of a crank press according to a first embodiment of the present invention, and FIG. 2 is a time chart of each control valve in the crank press.

In FIG. 1, the crankshaft 1, connecting rod 2, brake 6, clutch 7, flywheel 8, motor 9, brake control valve SV1 and clutch control valve SV2 are shown in FIG.
Is similar to the conventional example shown in FIG. Although not shown in FIG. 1, the slide 3 and the balance cylinder 4 are provided similarly to the basic structure example shown in FIG.

This embodiment is characterized in that the following hydraulic circuit portion is added to the above configuration, and the added portion will be described next. A gear 11 coupled to the crankshaft 1
A gear 12 connected to the drive shaft of the hydraulic pump / motor 10 meshes. The hydraulic pump / motor 10 constitutes an energy absorbing unit, and is a hydraulic device that functions as a hydraulic pump and also functions as a hydraulic motor. In other words, when it receives a driving force from the crankshaft 1 side, it operates as a hydraulic pump, and when it receives supply of pressurized oil and rotates, it operates as a hydraulic motor that applies rotational force to the crankshaft 1 side. Specific examples of the hydraulic pump / motor 10 include a gear pump type, a vane pump type, and a piston pump type.

Two hydraulic paths a and b are connected to a hydraulic oil supply / discharge port of the hydraulic pump / motor 10, and an accumulator 13 is connected to the two hydraulic paths a and b via an oil path c. Have been. The first switching valve SV3 is connected to the oil passage a.
The oil passage b is provided with a second switching valve SV4. With the first switching valve SV3 and the second switching valve SV4,
The switching means described in the claims is configured.

The first switching valve SV3 and the second switching valve SV4
Are solenoid-driven four-port, two-position switching valves. The hydraulic pump / motor 10 communicates with the accumulator 13 at the I position switched by the solenoid, and the oil passage c of the accumulator 13 at the spring biased II position. Are shut off from the oil passages a and b, and the pressure oil in the accumulator 13 is held. Also, while the solenoid is demagnetized, it is always kept at the position II by a spring.

A check valve 15 is provided in the oil passage b in such a direction as to allow the supply of the pressurized oil to the accumulator 13 and prevent the discharge of the pressurized oil from the accumulator 13. Further, an oil passage d branches off from an oil passage c to which the accumulator 13 is connected, and serves as a hydraulic pressure supply passage for clutch operation. A clutch control valve SV2 is interposed in the oil passage d. Therefore, when the clutch control valve SV2 is opened, the clutch 7 can be switched and controlled by the pressure oil in the accumulator 13. Therefore, in the present embodiment, a bulky compressor and a large air tank are not required, so that the crank press can be made compact and a press that does not generate exhaust noise can be provided.

The hydraulic pump 16 and the opening / closing valve 17 in the oil passage d connected to the oil passages a and b are used for supplying hydraulic oil at the beginning of operation and for replenishment in case of oil leakage. Reference numeral 18 denotes a pressure switch for checking the accumulated pressure in the accumulator 13. When the pressure in the accumulator 13 becomes equal to or less than a specified value, the pressure switch 18 is operated, the hydraulic pump 16 is started, and the on-off valve 17 is opened.
Is opened, and hydraulic oil can be supplied to the accumulator 13 and the oil passage c.

Next, a method of operating the crank press will be described with reference to FIG. (1) First, when lowering the slide, brake control valve
The brake 6 is released by SV1 and then the first switching valve SV
3 Switch to the I position. Then, the accumulator 13
The internal pressure oil flows through the oil passages c → a → b and rotates the hydraulic pump / motor 10. The check valve 15 does not allow the pressure oil to flow from the oil passage c to the oil passage b. Since the rotational torque of the hydraulic pump / motor 10 is transmitted to the crankshaft 1 via the gears 12 and 11, the press starts. That is,
The press is started by the hydraulic energy in the accumulator 13. Clutch control valve at the same time as the first switching valve SV3
SV2 is also switched, and the pressure oil in the accumulator 13 is supplied to the clutch 7 to connect the clutch 7. Thus, the crankshaft 1 is rotated by the energy stored in the flywheel 8 and the energy of the electric motor 9. That is, the driving of the crankshaft 1 is performed by the accumulator 1
3 and the energy of the electric motor 9 are combined. The first switching valve SV3 is demagnetized when steady rotation is obtained, and the oil passage c of the accumulator 13 is shut off. In this state, the hydraulic pump motor 10
Each port is connected to the tank 14 and rotates accordingly. In this way, the slide is lowered to the bottom dead center and stamping is performed. When the slide reaches the bottom dead center, the clutch 7 is disconnected by the clutch control valve SV2.

(2) After the stamping, the slide starts to rise, but the second switching valve SV4 is switched to the position I while the slide is rising. In this state, since the slide 3 moves up due to inertia, the hydraulic pump / motor 10 is rotated by the eccentric shaft 1 via the gears 11 and 12, and the tank 1
Hydraulic oil in 4 is sucked in through oil passage a and supplied to accumulator 13 through oil passages b and c. Since the check valve 15 in the oil passage b is in the forward direction, the flow of the hydraulic oil is allowed. In this way, the working oil is supplied to the accumulator 13 by the kinetic energy of the slide. That is,
It accumulates pressure to convert kinetic energy to hydraulic energy.

Immediately before the slide reaches the top dead center, the brake control valve SV1 is switched, the second switching valve SV4 is excited, and at the same time, the brake control valve SV1 is also demagnetized and the brake 6 starts to work. Stop. Even after the slide reaches the top dead center, it is held by the brake 6 and the slide is stopped at the top dead center for a desired time. In the next cycle, the above (1) and (2) may be repeated again.

In the crank press of the present embodiment,
There are the following advantages. 1: To convert the slide kinetic energy before press stop to hydraulic energy and store it in the accumulator 13,
Since the energy consumed thereby has a braking effect, the capacity of the brake can be reduced. 2: When the press is started (at the start of descent), the hydraulic energy stored by the kinetic energy at the time of sliding up can be used, so that the capacity of the electric motor for driving the press can be reduced. 3: The clutch transmission at the time of clutch connection is changed from dynamic friction to close to static friction, and wear of the clutch lining can be suppressed. 4: The clutch and brake can be disconnected smoothly when the press is started and stopped, and the generation of vibration and noise is reduced. 5: Since a bulky compressor and a large-capacity air tank are not required, the crank press can be made compact, and a press free of exhaust noise can be obtained.

Next, another embodiment of the energy absorbing means in the present invention will be described with reference to FIG. 10A is a hydraulic pump / cylinder in which a piston rod is connected to the crankshaft 1. The connection point of the piston rod can be connected to the connecting rod 2 in addition to the crankshaft 1 described above. One end of an oil passage b is connected to the opposite rod side chamber 4 ′ of the balance cylinder 4. In this embodiment, one end of each of oil passages a and b has a hydraulic pump / cylinder 10A and a balance cylinder 4A.
The other points are the same as those of the embodiment of FIG. 1 except that they are divided and connected. In this embodiment, since the energy absorbing means includes a cylinder as a component, there is an effect that the operation efficiency can be further improved as compared with the hydraulic pump / motor of the embodiment of FIG.

[0021]

According to the first aspect of the present invention, the capacity of the brake for stopping the slide can be reduced, and the hydraulic oil for the clutch is obtained from the hydraulic circuit of the energy absorbing means. This eliminates the need for a compact crank press and eliminates exhaust noise. According to the second aspect of the present invention, the mutual conversion between the kinetic energy and the hydraulic energy is performed, so that the capacity of the brake can be reduced. According to the third aspect of the invention, since the kinetic energy and the hydraulic energy are mutually converted, the capacity of the brake can be reduced. Further, since the balance cylinder is used as the energy absorbing means, the operation efficiency is improved as compared with the hydraulic pump / motor.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a crank press according to an embodiment of the present invention.

FIG. 2 is a time chart of each control valve in the crank press.

FIG. 3 is another hydraulic circuit diagram of the energy absorbing means in the present invention.

FIG. 4 is a basic structural diagram of a crank press.

FIG. 5 is a configuration diagram around a brake / clutch of a conventional crank press.

FIG. 6 is an operation time chart of a conventional crank press.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Connecting rod 6 Brake 7 Clutch 10 Hydraulic pump / motor 13 Accumulator SV1 Brake control valve SV2 Clutch control valve SV3 First switching valve SV4 Second switching valve

Claims (3)

[Claims] 1. The power of an electric motor is transmitted to a crankshaft via a clutch to lower a slide, and a brake connected to the crankshaft is used to slow down the rise of the slide. A crank press for stopping, provided with energy absorbing means for converting and absorbing a part of kinetic energy at the time of sliding up to hydraulic energy, and connecting an operating circuit of the clutch to a hydraulic circuit constituting the energy absorbing means. A crank press characterized by the following. 2. A hydraulic pump / motor connected to a gear rotating with the crankshaft and receiving a rotational force from the crankshaft; and an accumulator connected to the hydraulic pump / motor by a hydraulic circuit. 2. The crank press according to claim 1, further comprising switching means for switching between an energy absorbing state in which hydraulic oil is sent to the accumulator via the hydraulic pump / motor and a state in which hydraulic oil is returned to the tank. 3. The energy absorbing means includes an accumulator connected to an opposite rod side chamber of a balance cylinder incorporated in a crank press by a hydraulic circuit, an energy absorbing state for sending hydraulic oil to the accumulator, and returning the operating oil to a tank. 2. The crank press according to claim 1, further comprising switching means for switching between the state and the state.