JPH0550299A - Dry type cold hydrostatic pressure pressurizing device - Google Patents

Abstract

PURPOSE:To surely prevent a lock by holding axial force at the time of pressure forming by a backup cylinder, and also, eliminating an inclination of a piston of the backup cylinder. CONSTITUTION:In a press frame 20, a high pressure vessel 21 and a backup cylinder 29 are vertically provided. In a piston 30 of the backup cylinder 29, a large diameter piston part 33 and a small diameter piston part 34 are provided concentrically, and in a cylinder 31 in which the piston 30 is fitted so as to be freely slidable vertically, a large diameter cylinder part 37 corresponding to the large diameter piston part 33 and a small diameter cylinder part 38 corresponding to the small diameter piston part 34 are provided concentrically. Also, a large diameter cylinder chamber 45 and a small diameter cylinder chamber 46 are allowed to communicate with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry cold isostatic pressing device.

[0002]

2. Description of the Related Art Conventionally, a dry cold isostatic pressing apparatus for molding fine powder such as ceramics or metal powder into a uniform and high density is conventionally constructed as shown in FIG. That is, in FIG. 3, 1 is a retractable press frame in the form of a short frame. Reference numeral 2 is a cylindrical high-pressure container, and an upper lid 3 and a lower lid 4 are fitted on the opening sides of the upper and lower ends, and these lids 3, 4 are
An upper punch 5 and a lower punch 6 are provided through the.
7 is a molded rubber mold, which is interposed between the upper and lower lids 3 and 4 in the high-pressure container 2. It is designed to pressurize 9.

A backup cylinder 9 is interposed between the lower punch 6 and the lower side of the press frame 1 so as to hold the molding pressure (axial force) generated in the high-pressure container 2. The backup cylinder 9 is composed of a lower pressing plate 10, a cylinder 11 fitted to a support portion of the lower pressing plate 10, and a piston 12 fitted to the cylinder 11 so as to be vertically slidable. A plurality of rods 13 and coil springs 14 are circumferentially provided between the lower pressing plate 10 and the flange portions 10a, 12a of the piston 12 so as to urge the piston 12 downward. Reference numeral 15 is a pressure inlet.

[0004]

When the press frame 1 is swung and retracted, the pressure of the backup cylinder 9 is released, and the piston 12 is pulled downward by the spring 14 so that the space between the inner surface of the press frame 1 and the upper punch 5, etc. Secure a vertical gap.
In this type of device, since the entire device needs to be compact (the height is made low), the height H of the backup cylinder 9 is kept low, and the stroke is 5
It is suppressed to about mm. Therefore, backup cylinder 9
The ratio of the piston height l to the piston diameter D becomes smaller (currently about 0.14), and the backup cylinder 9 may be twisted and locked.

Further, in the backup cylinder 9, a pressure medium of 700 kgf / cm ² is used in order to make the inner diameter of the cylinder as small as possible to make it compact. Therefore, at the time of pressure molding, the cylinder 12 bulges about 0.3 to 0.8 in its diameter, and the cylinder 12 cannot guide the piston 12. In view of such a point, an object of the present invention is to enable the backup cylinder to retain the axial force at the time of pressure molding, and to prevent the inclination of the piston of the backup cylinder to reliably prevent the lock.

[0006]

SUMMARY OF THE INVENTION The present invention is a dry cold isostatic pressurizing device having a press frame 20 and a high pressure container 21 and a backup cylinder 29 which are vertically arranged in a press frame 20. The piston 30 of the backup cylinder 29 has a large diameter. The piston part 33 and the small-diameter piston part 34 are concentrically provided, and the large-diameter piston part is attached to the cylinder 31 into which the piston 30 is vertically slidably fitted.
A large diameter cylinder portion 37 corresponding to 33 and a small diameter cylinder portion 38 corresponding to the small diameter piston portion 34 are concentrically provided, and a large diameter cylinder chamber 45 and a small diameter cylinder chamber 46 are communicated with each other.

[0007]

Since the small-diameter piston portion 34 and the small-diameter cylinder portion 38 are provided, these can effectively guide the piston 30 and prevent its inclination. Further, since the large diameter cylinder chamber 45 and the small diameter cylinder chamber 46 are communicated with each other, the axial force applied to the piston 30 during molding can be reliably retained.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1 and FIG. 2, 20 is a press frame formed in the shape of a short frame. 21 is a cylindrical high-pressure container,
An upper lid 22 and a lower lid 23 are fitted on both upper and lower ends, and an upper punch 24 and a lower punch 25 are provided via the lids 22 and 23. 26 is a molded rubber mold in which the powder 27 is put. 28 is a pressure rubber type.

Reference numeral 29 is a backup cylinder, which is a high-pressure container 21.
It is interposed between the lower punch 25 on the lower side and the lower side of the press frame 20 so as to hold the molding pressure (axial force) generated in the high-pressure container 21. The backup cylinder 29 is
It includes a piston 30, a cylinder 31, and a lower pressing plate 32. The piston 30 includes a large-diameter piston portion 33 and a small-diameter piston portion 34 concentrically provided in the center of the large-diameter piston portion 33.
It consists of and. The small-diameter piston part 34 is fitted from below into a recess 35 formed in the central part of the large-diameter piston part 33, and is fixed to the large-diameter piston part 33 by bolts 36.

The cylinder 31 is composed of a large diameter cylinder portion 37 into which the large diameter piston portion 33 is slidably fitted, and a small diameter cylinder portion 38 into which the small diameter piston portion 34 is slidably fitted. The lower pressing plate 32 is concentrically provided with a support portion 39 that vertically corresponds to the large-diameter piston portion 33, and a large-diameter cylinder portion 37 is externally fitted to the outer periphery of the support portion 39 and fixed by a retaining ring 40 and a bolt 41. ing. A recess 42 is formed in the center of the support portion 39 of the lower pressing plate 32, and the small diameter cylinder portion 38 is formed in the recess 42.
Are fitted inside and fixed by bolts 43.

A pressure introducing port 44 is formed in the lower pressing plate 32, and a communication passage 47 for communicating a large diameter cylinder chamber 45 and a small diameter cylinder chamber 46 is formed in the small diameter piston portion 34. 48 and 49 are sealing materials, 50 is lower support plate, 51 is rod, 52
Is a coil spring. In the above-mentioned configuration, the pressure medium is introduced from the pressure inlet port 44 at the time of pressure molding, and the large / small cylinder chamber 4
Supply the pressure medium to 5,46 and raise the piston 30.
Since the molding pressure (axial force) generated in the high-pressure container 21 is held in this state, the axial force can be reliably received by the front surface of the piston 30.

When the press frame 20 is swung and retracted, the pressure medium is removed and the piston 30 is lowered by the spring 52. At the time of pressure molding, the pressure medium is supplied to the large and small cylinder chambers 45 and 46 to retain the axial force as described above, but the small diameter cylinder part 38 has a smaller inner diameter than the large diameter cylinder part 37. Even if the pressure medium in the small diameter cylinder chamber 46 acts, the small diameter cylinder portion 38 is slightly deformed. Further, the small diameter cylinder portion 38 is fitted in the support portion 39 of the lower pressing plate 32, and the outer peripheral side is surrounded by the support portion 39, so that the deformation thereof is further slight.

Therefore, since the small diameter piston portion 34 is vertically slidably fitted in the small diameter cylinder portion 38 which is slightly deformed as described above, these effectively act as a guide for the piston 30 and tilt the piston 30. Guide up and down without fail. Therefore, the piston 30 can be prevented from being locked. In the embodiment, the large-diameter piston portion 33 of the piston 30 is
The small-diameter piston portion 34 and the small-diameter piston portion 34 are separate bodies, but they may be integrated. In addition, the large diameter cylinder portion 37 of the cylinder 31,
The small diameter cylinder portion 38 may be integrated with the lower pressing plate 32, or only the small diameter cylinder portion 38 may be provided separately from the lower pressing plate 32.

[0014]

According to the present invention, a backup cylinder
29 piston 30 with large diameter piston part 33 and small diameter piston part 34
Are provided concentrically with each other, a cylinder 31 into which the piston 30 is vertically slidably fitted, a large diameter cylinder portion 37 corresponding to the large diameter piston portion 33, and a small diameter cylinder portion 38 corresponding to the small diameter piston portion 34. And are installed concentrically and have a large diameter cylinder chamber
Since the 45 and the small-diameter cylinder chamber 46 are communicated with each other, the axial force at the time of pressure molding can be retained, and the inclination of the piston 30 can be eliminated to reliably prevent the lock.

[Brief description of drawings]

FIG. 1 is an overall sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part showing an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 20 Press frame 21 High pressure container 29 Backup cylinder 30 Piston 31 Cylinder 32 Lower pressing plate 33 Large diameter piston section 34 Small diameter piston section 37 Large diameter cylinder section 38 Small diameter cylinder section 45 Large diameter cylinder chamber 46 Small diameter cylinder chamber 47 Communication passage

Claims (1)

[Claims] 1. A dry cold isostatic pressurizing device comprising a press frame (20) having a high-pressure container (21) and a backup cylinder (29) provided above and below the piston (30) of the backup cylinder (29). A cylinder in which the large-diameter piston part (33) and the small-diameter piston part (34) are concentrically provided, and the piston (30) is vertically slidably fitted.
(31) has a large diameter cylinder that corresponds to the large diameter piston (33).
(37) and the small diameter cylinder part corresponding to the small diameter piston part (34)
(38) is provided concentrically, and the large diameter cylinder chamber (45) and the small diameter cylinder chamber (46) are communicated with each other, a dry cold isostatic pressurizing device.