JPH04237600A - Compression molding machine - Google Patents

Abstract

PURPOSE:To obtain a desired function with a simple construction by interlocking a center mold for molding via rack gears and a pinion gear to a movable punch. CONSTITUTION:An upper punch 2 for molding is fixed to the under surface of a hydraulic cylinder 1 of the compression molding machine. A cavity 6 for housing raw materials for molding is formed between the center mold 3 provided in the peripheral side part of the stroke of the upper punch 2 and a lower punch 5 for molding on a lower base plate 4. The rack gear 7 is fixed to the hydraulic cylinder 1 and the rack gear 8 is fixed to the base plate 4. The pinion gear 9 is provided between the two rack gears 7 and 8. The pinion gear 9 and the center mold 3 are coupled by a connecting plate 10. The center mold 3 for molding is interlocked to the movable punch 2 via the rack gears 7, 8 and the pinion gear 9. The product having high quality is produced in this way.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a with-drawal type compression molding machine. This molding machine is applicable to compression molding of all kinds of materials, both natural and artificial, including inorganic materials such as metals, stones, ceramics, and carbon, and organic materials such as wood, elastomers, thermosetting resins, and thermoplastic resins. Although it is possible, it is particularly suitable for compression molding of powders of these materials.

0002

2. Description of the Related Art Generally, when powder is uniaxially pressed, the pressure force is not uniformly transmitted within the molded product. As a result, the density of the molded product becomes uneven, the predetermined density of the molded product cannot be obtained, or the molded product has poor appearance such as cracks. To solve these problems, a method called withdrawal press has recently been proposed. Below, the basic operation of this method will be explained according to Fig. 2. When the movable upper punch a descends to perform compression molding of the powder b, the molding middle mold c moves slightly downward in conjunction with the movement of the upper punch a. However, a compression method in which a forming operation is finally performed such that the middle mold c moves by Δh2 with respect to the stroke distance Δh1 of the upper punch a is called a with-drawal press. At that time, Δh
It is said that 2/Δh1=1/2 is the optimal condition. In the figure, d is the lower punch fixed to the substrate, e is the powder b
This is a molded product obtained by compression molding.

[0003] Uniaxial pressure type compression molding machines are roughly classified by pressure driving force into mechanical presses using cam drives and hydraulic presses using hydraulic cylinders, but the with-drawal press method employs both. . Note that the driving force for medium-sized presses is mainly cam drive in the case of mechanical presses, and mainly hydraulic drive in the case of hydraulic presses.

0004

[Problems to be Solved by the Invention] In the case of a hydraulic with-draw press, while it has the advantage that the pressurizing force is large and constant, it has two hydraulic cylinders for driving the movable punch and a hydraulic cylinder for driving the medium-sized punch. This required a very large hydraulic circuit, making the entire device complex and expensive. On the other hand, mechanical presses have the advantage that the height of the press-molded product is constant due to its mechanism, but if the raw material powder is not supplied in a fixed amount at a time, the density of the molded product will not be constant, and the pressure Since the pressing force is lower than that of a press, there is a problem that the molded product cannot be made to have a high density, so it is not generally applied to the production of high-quality products.

[0005] Therefore, an object of the present invention is to make it possible to perform a predetermined function by extremely simple and inexpensive means.
To provide a with-drawal type compression molding machine.

[0006]

[Means for Solving the Problems] This compression molding machine is a with-drawal type compression molding machine, and is characterized in that a medium die for molding is linked to a movable punch via a rack gear and a pinion gear. be.

[0007]

According to this compression molding machine, the middle mold for molding is interlocked with the movable punch via the rack gear and the pinion gear, so that the middle mold and the movable punch perform a with-drawal molding operation. Further, when the molding machine is a hydraulic press, the hydraulic system is only a drive system for the punch, and the structure as a whole is very simple, but it has a predetermined function.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the compression molding machine of the present invention will be explained below based on the embodiment shown in FIG. 1, which is applied to a hydraulic press. In the figure, 1 is a hydraulic cylinder, 2 is an upper forming punch fixed to the lower surface of the hydraulic cylinder, and moves vertically with the movement of the cylinder.
A cavity 6 for accommodating the molding raw material is formed between the molding punch 5 and the molding lower punch 5 fixedly installed on the lower base 4. On the other hand, a single or multiple rack gears 7 are fixed to the circumferential side of the hydraulic cylinder 1 via a heat plate attached to the cylinder as necessary, and the lower part of the rack gear 7 hangs downward to accommodate a medium-sized rack gear 3. It reaches the circumferential side. Further on the circumferential side of this rack gear 7, one or more other rack gears 8 are installed at intervals on the base 4. A single or plural pinion gears 9 are provided between both rack gears 7 and 8, and the tips of their teeth mesh with each other, and the shaft center of the pinion gear 9 and the medium 3
are connected by a connecting plate 10. In addition, instead of the above structure, this pinion gear may be a speed change or reduction gear that combines multiple gears, and the combination structure of this gear and both rack gears may also be a combination of two or more sets of these gears, or multiple pinion gears. This includes various modifications and improvements, such as those in which both rack gears are engaged.

In the above embodiment, when the pinion gear 9 is single, when the hydraulic cylinder 1 descends, the rack gear 7 also descends together with the upper punch 2, and due to this movement, the pinion gear 9 also descends while rotating. As a result of this lowering, the middle mold 3 also descends via the connecting plate 10. At this time, the descending speed of the middle die 3 is always 1/2 of the descending speed of the upper punch.
Therefore, this molding machine performs a with-drawal molding operation. In this case, apparently, upper and lower punches 2,
5 are approaching and leaving at relatively the same speed. However, the speed ratio between the middle punch 3 and the upper punch 2 is not particularly limited to 1/2, and the speed ratio can be increased to 1/2 or more or lower by using a transmission, reducer, irregularly shaped gears, etc. (not shown). It may be.

[0010] As shown in the above embodiment, the compression molding machine of the present invention is particularly capable of performing with-drawing operation by attaching a simple device to a general-purpose single-shaft single-side pressure hydraulic molding machine and modifying it. However, the effect of installing this mechanism is not limited to the above-mentioned hydraulic press, but can be similarly brought about by mechanical presses or other types of press machines, so the compression molding of the present invention It is self-evident that the machine also includes all these methods.

[0011]

[Effects of the Invention] In the compression molding machine of the present invention, for example, when this is a uniaxial pressure type compression molding machine having a single hydraulic cylinder, the entire hydraulic system is very simple, with only the punch drive system. Although it is a structure, it still has a predetermined function. Therefore, the present invention is industrially extremely effective and innovative.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view schematically showing a compression molding machine according to the present invention.

FIG. 2 (1) to (5) are explanatory diagrams showing the steps of a compression molding machine according to the prior art.

[Explanation of symbols]

2...Movable punch, 3...Medium size, 7, 8...Rack gear, 9...Pinion gear.

Claims (1)

[Claims] 1. A with-drawal type compression molding machine, characterized in that a medium die for molding is interlocked with a movable punch via a rack gear and a pinion gear.