JPS6150720B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ram type hydraulic press machine capable of pressurizing a mold at high pressure and high speed.

A ram-type hydraulic press machine used to pressurize powders, etc., has cylinder rams on both sides of a cylinder ram made with a large diameter to generate high pressure, as shown in Japanese Utility Model Publication No. 40-33563, for example. A pair of sub-cylinders made with a small diameter for rapid movement are separately provided so that the pressure plate for attaching the upper die can move up and down at high speed by the operation of the sub-cylinders. The first press machine of this kind
An example is shown in the figure. In the figure, a is a pressure plate that moves up and down, b is a frame, c is a pair of small diameter sub-cylinders provided to move the pressure plate up and down at high speed, and d
is a ram fixedly installed on the pressure plate a, e is a large-diameter cylinder hole into which the ram is loosely inserted, and f is a ram chamber constituted by the ram and the cylinder hole. g is a pre-fill valve (also called a surge valve or surge check valve) provided on frame b, h is a double-acting cylinder that moves the valve body i, j is an auxiliary oil tank, and k is opened and closed by the valve body i. Auxiliary oil tank
and a communication port between the high pressure chamber f, and l is an inlet for high pressure oil. In this press machine, when the sub-cylinder c is extended and the pressure plate a is lowered with the communication port k open, the ram chamber f becomes negative pressure, hydraulic oil is sucked from the auxiliary oil tank j, and then the double-acting cylinder The communication port k is closed by the operation of h, and high pressure oil is supplied from the inlet port l to the ram chamber f.
However, even when attempting to open the communication port k, the high pressure in the ram chamber f is applied to the valve body i, so that the pressure plate a is forced down by the double-acting cylinder h. does not open easily, and for this reason, in the past, the communication port k could only be opened after some hydraulic oil was drained from the inlet port l to lower the pressure in the ram chamber f. This has the disadvantage of causing time loss and slowing down the operation. In addition, in all conventional pre-fill valves, the valve element i does not narrow the flow path cross section of the hydraulic oil, so this creates resistance when the hydraulic oil flows back and forth between the auxiliary oil tank j and the ram chamber f. This was one of the factors that made it difficult to increase the vertical movement of the platen a.

On the other hand, in this type of press machine, a known pressure intensifier is interposed in the piping connecting the hydraulic pump (not shown) and the inlet l of the ram chamber f, so that even higher pressurizing force can be obtained during molding. However, this requires space for installing a pressure intensifier next to the press machine, and also requires piping that can withstand high pressure, which has the drawback of being easily damaged.

In order to eliminate this drawback, Jikoko Sho 53-1094
A device in which a pressure intensifier is integrally formed within the ram is known, such as the device shown in No. Since the piping from the hydraulic pump had to be connected to the piping (also known as .), it could not be constructed without using flexible piping such as rubber, which was difficult as a reinforcement measure against damage.

The present invention was made with the aim of eliminating these drawbacks of conventional ram type hydraulic press machines, increasing the operating speed, and simplifying and compacting the configuration. A large-diameter cylinder hole is formed in the center of the frame, and a ram fixed vertically to the pressure plate is loosely inserted into the cylinder hole, and the cylinder hole and the ram form a ram chamber. The prefill valve provided on the frame is configured such that by moving the spool up and down, a valve portion formed at the lower end opens and closes the communication port between the ram chamber and the auxiliary oil tank, and The cylindrical part above the spool forms a pressurizing chamber into which the ram chamber is inserted airtightly, and the pressurizing chamber and the ram chamber are communicated through a through hole formed in the center of the spool. It consists of a cylinder with a protruding piston shaft.

An embodiment of the present invention will be described below with reference to FIGS. 2 to 5.

Frame 1 is supported horizontally by columns (not shown) vertically erected on a device base (not shown), and frame 2 is a frame 2 on which the upper mold of the mold is fixed. The platen is shown. The pressure plate 2 and the frame 1 are connected via a pair of sub-cylinders 3, 3 made to have a small diameter for high-speed operation, and a hydraulic power source ( When low pressure oil is supplied from a switching valve (not shown) through a switching valve (not shown), the pistons of the sub cylinders 3, 3 move, causing the pressure plate 2 to move up and down at high speed. 6 is a large-diameter cylinder hole formed in the center of the frame, and a large-diameter ram 7 fixed vertically on the pressure plate 2 is loosely inserted into the large-diameter cylinder hole. A ram chamber 8 is formed on the ram 7 by the cylinder hole 6 and the ram 7. Reference numeral 9 denotes a pre-filled valve provided on the frame 1, and the pre-filled valve has a cylindrical spool 10 disposed in a hard hole so as to be movable up and down, and a valve portion 11 formed at the lower end of the spool 10 in a valve chamber 12. The valve portion 11 faces the communication port 13 with the ram chamber 8. 14
is an auxiliary oil tank that is always in communication with the valve chamber 12, and the inside of the tank is open to atmospheric pressure. A flange-shaped piston portion 15 is integrally formed on the outer periphery of the spool 10,
A cylinder chamber 17 connected to the refueling boat 16 is formed on the upper side of the piston portion 15, and the refueling boat 1 is formed on the lower side.
A cylinder chamber 19 that is continuous with 8 is formed. Also, a cylindrical portion 20 above the piston portion 15 of the spool 10
The diameter B of the cylindrical portion 20 is formed to be the same as the diameter A of the communication port 13, and the cylindrical portion 20 is held airtight by sliding a U-button 21 on the outer periphery of the pressurizing chamber 22 (Fig. 4). , see Figure 5). A series of through holes 23, 2 are formed in the center of the spool 10, with a small diameter in the lower half and a large diameter in the upper half.
4 is provided, and the pressurizing chamber 2 is provided through the through holes 23 and 24.
2 and the ram chamber 8 are communicated with each other. 25 is a pressure increasing cylinder fixed to the upper part of this prefill valve 9;
A piston shaft 27 extending downward from the piston 26 of the cylinder passes through the center opening of the seal member 28 and loosely inserts into the pressurizing chamber 22 . Reference numeral 29 indicates an oil supply port that is connected to the upper chamber of the piston 26 of the pressure increasing cylinder 25, and 30 is an oil supply port that is connected to the lower chamber of the piston 26. Note that 31 indicates an oil supply port communicating with the ram chamber 8. The piston shaft 27 is formed to have a diameter slightly smaller than the inner diameter of the through hole 24, and can loosely fit into the through hole 24 in a non-airtight manner.

Next, to explain the operation of this press machine, in Fig. 2, the pressure plate 2 is in the raised position, the communication port 13 is open, and the ram chamber 8 is in communication with the auxiliary oil tank 14. At this time, the sub cylinder When pressure oil is supplied from the hydraulic source to the piping 4 of 3, 3, the pressure plate 2 descends at high speed, and the upper mold attached to the pressure plate 2 joins the lower mold. At this time, as the ram 7 descends, the inside of the ram chamber 8 becomes negative pressure, so oil in the auxiliary oil tank 14 is sucked into the ram chamber 8 through the communication port 13. (This state is shown in Figure 3). Subsequently, pressurized oil is supplied to the oil supply port 16 and the pressure is applied to the upper surface of the piston part 15, thereby lowering the spool 10 and opening the valve part 11 to the communication port 1.
3 to cut off communication with the auxiliary oil tank 14, pressurized oil is supplied to the oil supply port 31 to raise the oil pressure in the ram chamber 8 to a certain level. (Figure 4 shows this state). Thereafter, the oil supply port 31 is closed and pressurized oil is supplied to the oil supply port 29 to lower the piston 26 as shown in FIG. 5 and advance the piston shaft 27 into the pressurizing chamber 22. Pressurized chamber 22
As mentioned above, the ram chamber 8 communicates with the ram chamber 8 through the through holes 23 and 24, so the ram chamber 8 becomes high pressure and presses down the ram 7, so that the upper die fixed to the pressure plate 2 is strongly pressed against the lower die. Can be crimped. When the desired press forming process is completed, pressurized oil is supplied to the oil supply port 18 to raise the spool 10 and open the communication port 13.
In this case, the diameter A of the communication port 13 and the diameter B of the cylindrical portion 20 are equal, and the ram chamber 8 and the pressurizing chamber 22 are always in communication, so that when the communication port 13 is closed as shown in FIG. The pressure applied to the lower end face and the pressure applied to the upper end face are equal. That is,
Even if the pressure in the ram chamber 8 increases, it remains at the same pressure as the pressure chamber 22, so equal pressure is always applied to both end faces of the spool 10, and the two pressures cancel each other out. For this reason, the spool 10 always moves up and down slightly and the oil supply port 16 or 1
The communication port 13 can be easily opened and closed by normal pressure oil supply applied to the port 8.

Note that the oil supply port 31 supplies hydraulic oil from a hydraulic source at normal pump pressure to prepress the ram chamber 8, but this preload is supplied to the pressurizing chamber 2 of the piston shaft 27
2. When the volume of advancement into the interior is large, it is not necessarily necessary as a process. Also, the through hole 24 is formed to have a larger diameter than the through hole 23 so that the piston shaft 27 can fit loosely therein, but this means that the pressure chamber 22 is higher than the example diagram and is above the spool 10. It is not necessary when the end face and the lower end of the piston shaft 27 do not collide. However, by configuring them so that they fit loosely into each other in this way, it is possible to further reduce the size.

As described above with respect to the embodiments, the ram type hydraulic press machine according to the present invention forms a pressurizing chamber into which the cylindrical part above the spool is inserted airtightly, and the pressurizing chamber and the ram chamber are connected to each other by the spool. It communicates through a through hole formed in the center, and the piston shaft of the pressure increasing cylinder protrudes into the pressurizing chamber, so the pressure applied to both end surfaces of the spool is always balanced regardless of the pressure in the ram chamber, and the spool is lightened. It can move up and down, making it easy to open and close the communication port, increasing the speed of press machine operation, and at the same time, there is no need to use flexible hydraulic piping connected to the pressure boosting cylinder, resulting in excellent durability. Furthermore, the present invention is advantageous in that it does not require a separate pressure intensifier, has a compact configuration, and can provide a hydraulic press with a high pressurizing force.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the main parts of a conventional ram-type hydraulic press machine, FIG. 2 is a longitudinal cross-sectional view of the main parts of a ram-type hydraulic press machine showing an embodiment of the present invention, 4 and 5 are longitudinal sectional views showing the operating state thereof. DESCRIPTION OF SYMBOLS 1... Frame, 2... Pressure plate, 3, 3... Sub cylinder, 6... Large diameter cylinder hole, 7... Ram, 8... Ram chamber, 9... Prefill valve, 10...
...Spool, 11...Valve section, 12...Valve chamber, 13
... Communication port, 14 ... Auxiliary oil tank, 15 ... Piston part, 20 ... Cylindrical part, 22 ... Pressure chamber, 2
3, 24...through hole, 25...pressure increase cylinder,
27...Piston shaft.

Claims (1)

[Claims] 1. A pressure plate is arranged to be movable up and down with respect to a frame via a sub-cylinder, a large diameter cylinder hole is formed in the center of the frame, and a ram fixed perpendicular to the pressure plate is installed in the cylinder hole. The pre-filled valve provided on the frame is loosely inserted so that the cylinder hole and the ram form a ram chamber, and by moving the spool up and down, the valve portion formed at the lower end of the pre-filled valve is connected to the ram chamber and the auxiliary oil tank. The communication port is configured to open and close, and the cylindrical portion above the spool forms a pressurizing chamber into which the ram chamber is inserted airtightly, and the pressurizing chamber and the ram chamber are connected through a through hole formed in the center of the spool. A ram type hydraulic press machine, characterized in that a piston shaft of a pressure increasing cylinder is communicated with the pressurizing chamber and further projects into the pressurizing chamber.