JPH0239903A - Powder molding machine - Google Patents

Abstract

PURPOSE:To prevent compressed powder from accumulating and fixing on a tooth face, remove the same easily always to be received on a new tooth surface, receive good bitings and releasings and also prevent the power from heating variation end energy loss by specifying unsymmetrical surface constitution of a saw type molding tooth of a roll. CONSTITUTION:A forced feeding surface 4 cut from a surface into the inner section by an angle alpha forming 5-35 deg. from a line C connecting the centers of both molding rolls up to the turning direction is formed, and a compressive molding surface 5 cut from both ends of said forced feeding surface cut to the surface by an angle beta forming 55-85 deg. similarly to the turning direction is formed. A number of saw type forming teeth 6 of inequililateral triangle shape uniformly dividing an outer peripheral surface 7 of the roll are formed by both of said surfaces. As most of the maximum compressive force generated in the center line C direction is applied to the formed surface while only a little compressive force is applied to the forced feeding surface 4, the raw material powder is not retained in the compressive forming section to a molded material S easily. The molding teeth, therefore, are not buried at all to keep always sharp biting.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a powder molding machine that compresses and molds raw material powder using a pair of molding rolls that rotate in opposite directions.

[Prior Art] In addition to the smooth roll 1a shown in FIG. 4, the forming rolls of this type of powder forming machine have square, triangular, and semicircular shapes on the surface of the forming roll as shown in FIGS. 5A-B-C. ib, 1c, and 1d, which have concave grooves arranged at equal intervals, were generally adopted.

In a powder forming machine using a smooth roll 1a, the biting angle θ of the forming roll is determined by the coefficient of friction between the raw material powder and the roll material.

In Fig. 4, the raw material powder surrounded by the cylinder 3a is Ya.
It is bitten from the point and compression molded at the point Xa. Therefore, Ya
Since the raw material powder Pa located between -Za is not bitten by the forming rolls, it slips on the surfaces of the rotating forming rolls 1a and 2a, resulting in loss of power. In addition, there was an adverse effect such as changes in the properties of the raw material powder due to frictional heat between the surface of the forming roll and the raw material powder.

In order to improve this, the fifth method was to create gear-like or saw-like forming teeth by carving cuts evenly on the outer periphery of the forming roll.
Figures A, B, and C all attempt to solve the above-mentioned problem of smooth rolls by biting teeth on the surface.

[Problems to be Solved by the Invention] A forming roll with forming teeth as shown in FIG. However, the compressive force caused by the powder that is gradually compressed from above inside the cylinder and reaches the surface of the forming roll acts equally on the entire surface of the cut forming tooth.

For this reason, the powder that has fit inside the molded teeth is further consolidated due to the external pressure that is applied one after another, and even after passing the maximum compression point Xa and being released from the pressure, it is easily held in the south direction. The molded teeth did not peel off, and in the end, all of the molded teeth were buried, leaving it no different from a simple smooth roll. Removing the powder agglomerates stuck between the tooth grooves and restoring the tooth profile requires extremely complicated work, so to solve the problem of smooth rolls,
I have to say that it is extremely inadequate.

In order to solve the above-mentioned problems, the present invention aims to provide a powder molding machine in which a molding roll is provided with molding teeth that do not easily become embedded and formless due to the compressive force of the powder that is applied. do.

[Means for Solving the Problems] The powder forming machine according to the present invention forms an angle of 5° to 35° in the width direction of the outer circumferential surface of the forming roll from a line connecting the centers of the box forming rolls in the direction of rotation. A large number of serrated molded teeth with a scalene triangular cross section are formed evenly on the circumference, forming an angle α and cutting from the surface to the inside, and also forming an angle β of 55° to 85° in the rotation direction and cutting from the inside to the surface. The above problem was solved by engraving.

[Operation/Example] The operation of the present invention will be explained based on FIG. 1 and FIG. 2 showing an example. In a powder forming machine in which a cylindrical body 3 is mounted above a pair of forming rolls 1 and 2 that are parallel to each other and rotate in opposite directions, a line C connecting the centers of the box forming rolls is traced back in the direction of roll rotation. A pressure wire forming surface that forms a forced feeding surface 4 that cuts inward from the surface at an angle α of 5° to 35°, and cuts back to the surface from both sides at an angle β of 55° to 85° in the same direction of rotation. 5, and a large number of scalene triangular saw-shaped molded teeth 6 are equally divided into the outer circumferential surface 7 of the roll on both sides. Now, when the powder P is supplied into the cylinder 3 and the forming rolls 1 and 2 are rotated, the powder P is bitten by the forming rolls and guided downward, but this action will be explained with reference to Fig. 2.
Since the biting of the raw material powder starts from point 7, it is located above the biting point Ya of the smooth roll, and the raw material powder between Y-2 is fed by the forced feeding surface 4, so new raw material powder is always fed. comes into contact with the forming roll surface and does not change the properties of the raw material powder due to the generation of frictional heat.

Moreover, in the case of the serrated molded tooth according to the present invention, unlike the conventional serrated molded tooth (Fig. 5 A, B, and C), the maximum compressive force generated in the direction of the center line C is mostly compressive. joins the molding surface,
Since only a small compressive force is applied to the forced feeding surface, the greatest feature is that it eliminates the retention of raw material powder in the compression molding section and makes it easier to peel off the molded product S. Therefore, the molded teeth do not become embedded and always maintain a sharp biting action, so the relationship shown in FIG. 2 continues unabated for a long time.

Note that FIG. 3 is a side view showing another embodiment, in which the serrated teeth 6 do not span the entire width of the roll outer circumferential surface 7, leaving some smooth surfaces at both ends.

[Effects of the Invention] As described above, the present invention has a unique effect due to the asymmetrical surface configuration of the serrated molded teeth, so that the compressed powder does not accumulate and stick to the tooth grooves, but easily peels off and is always replaced with a new tooth groove. It picks up the powder and repeats sharp biting and release to prevent thermal changes and energy loss in the powder, thereby solving the intended problem.

The angle α (5° to 35°) and angle β (55°) specified here are
(° to 85°) is an empirical value obtained by repeating patient experiments, but these angles can be changed depending on the properties of the raw material powder to ensure a better molding effect. -For forming raw material powder in a membrane, α+β is 90' to 110
The molding effect is achieved around 30°.

[Brief explanation of the drawing]

FIG. 1 is a partial front view showing the embodiment of the present application, FIG. 2 is a front view similarly explaining its operation, FIG. 3 is a side view showing another embodiment, and FIG. 4 is an explanation of the operation of the conventional technique. front view,
FIGS. 5A-5C are front partial views showing different conventional techniques. 1. Body... Forming roll, 3... Cylindrical body 4.
... Forced feeding surface, 5 ... Compression molding surface 6.
... Serrated molded teeth, 7 ... Roll outer peripheral surface C
... Line connecting the center of the roll, P ... Powder S ... Molded object

Claims (1)

[Claims] In a powder molding machine that includes a pair of forming rolls that are parallel to each other and rotate in opposite directions, and a cylindrical body that guides raw material powder between the forming rolls, both forming rolls are arranged in the width direction of the outer peripheral surface of the forming rolls. 5 going back in the direction of rotation from the line connecting the centers of
A serrated molded tooth with a scalene triangular cross section cuts from the surface to the inside by forming an angle α of 35° to 35°, and cuts from the inside to the surface by forming an angle β of 55° to 85° in the direction of rotation. A powder molding machine characterized by a large number of engravings evenly distributed on the circumference.