JP3563555B2 - Molded product unloading device in powder molding machine - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a device for carrying out a molded product having a shape that is easy to fall down, such as a cylindrical shape, from a powder molding machine without damaging it, and is mainly used in the field of powder metallurgy, but is also applicable to powder molded products in other fields. Applicable.
[0002]
[Prior art]
The powder molding in powder metallurgy will be briefly described by taking a sintered gear as an example (see FIG. 4). A die cavity formed by a die 10 for forming a gear tooth profile, a lower punch 20 and a core rod 30 for forming a shaft hole of the gear. By compressing the raw material powder filled into the space between the upper punch 40 and the lower punch 20, a product (molded product) having a desired shape can be obtained.
[0003]
In molding the powder, the die and the lower punch move up and down relatively to make the green density uniform, but depending on which of them is fixed to the press, the method of assembling the die set can be fixed to the die or lower. The movable punch type is roughly classified into a lower punch fixed and a die movable type generally called a withdrawal die set. Both types have no difference in the basic principle of powder molding.
[0004]
FIG. 4 shows one cycle of powder molding. In practice, the latter method is often used, but the drawing shows the former case of the fixed die and the movable lower punch, due to space limitations. (A) in the figure is a state in which the powder filled in the die 10 is subjected to compression molding, and after the upper punch 40 is raised from the figure and the lower punch 20 is raised to the upper surface of the die plate 51, (B) The molded article is extruded from the die as shown in FIG.
[0005]
Then, when the feeder 60 of the raw powder is moved from the standby position onto the die, the molded product is pushed away from the die to the right side of the die plate by the leading edge of the feeder. At the same time, the lower punch 20 is lowered to a predetermined filling depth (C to D), the powder is filled in the die, and the next compression molding is performed. During this repetition, the molded product displaced from the top of the die sequentially moves to the right end of the die plate, and then slides down on the chute 70 and is carried out of the powder molding machine. A flexible tube and a raw material hopper are connected to the powder supply port 61 of the feeder 60, and a drive source such as hydraulic pressure is connected to the drive rod 62, but they are omitted because they are obvious. In other drawings, the drive rod 62 is left to indicate the direction of the feeder, but the powder supply port may be omitted due to space limitations.
[0006]
[Problems to be solved by the invention]
Such a conventional carrying-out means has no problem when the object to be formed has a shape in which the bottom area is large compared to the height and hard to fall down, as in the gear illustrated in FIG. 3 (B). In the case of elongated molded products such as oil-impregnated bearings, they tend to fall over when they are pushed away from the die by the feeder or after moving to the chute, and if they fall down, they may be damaged or latent cracks may remain in the sintered product . For this reason, there has been a demand for a means capable of carrying out a molded product having a shape that easily falls without falling over.
[0007]
[Means for Solving the Problems]
The present invention extends the reciprocating stroke of the feeder 60, waits in the middle of the die plate for a restraining plate that can move forward and backward along with the operation of the feeder, and sandwiches the molded product between the leading edge of the feeder and the restraining plate. It is possible to eliminate the opportunity to fall on the die plate by moving the player in one operation to the top of the chute. Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
In FIG. 1, a pressing plate 81 positioned between a die (not shown) and a chute 70 so as to face the front edge of the feeder 60 horizontally slides through the chute 70 or a bracket 71 connected to the gantry thereof. The moving guide rod 82 and the compression spring 83 are supported so as to be able to advance and retreat in the same direction as the operation of the feeder 60. Numeral 84 is a nut for retaining, which also serves to finely adjust the spring pressure.
[0009]
As shown in (a), the molded product moves to the right while being pushed by the front edge of the feeder, and eventually touches the retaining plate 81, and the retaining plate pushes the molded product between the feeder and the repulsive force of the compressed spring 83. Retreat while holding the pinch. Then, as shown in (b), the lower end of the molded product is separated from the die plate, and the feeder is stopped where it floats above the chute 70. The strength of the compression spring 83 is sufficient to prevent the molded product from slipping off in this state (b).
[0010]
Next, when the feeder 60 starts to retreat, the molded product is released at that moment and slips down, and the lower end rides on the chute 70. Combined with the action of the pressing plate, which starts to return almost at the same time, pressing the upper part of the molded article, the molded article safely slides down the chute 70 with the lower end first. Thus, when the feeder 60 and the holding plate 81 return to their original positions, one cycle from molding to carrying out is completed. However, it is conventional that the die is filled with powder while the feeder reciprocates. Incidentally, the pressing plate may be advanced or retracted by hydraulic pressure or pneumatic pressure instead of the compression spring. In the case where the stroke of the advance / retreat is short, a highly elastic foam of a closed cell type may be used.
[0011]
As shown in FIG. 2, when a support member 63 having a recess conforming to the shape of the molded product is attached to the front edge of the feeder 60, gripping of the molded product and prevention of falling thereof can be ensured. It is more preferable that the support member be made of a cushioning material, since a shock to the molded product is prevented. If the chute 70 is provided with a groove that conforms to the shape of the molded product, the molded product can be sent to the next step in a fixed direction.
[0012]
【The invention's effect】
As described above in detail, according to the present invention, although the time required for one cycle is increased by an amount corresponding to the extension of the stroke of the feeder as compared with the related art, it is possible to safely carry out a molded product having a shape that easily collapses without damaging the molded product. There is a significant advantage in that the yield and product reliability are significantly improved. Therefore, the present invention is particularly useful for manufacturing a severely-sintered component such as a valve guide of an automobile engine.
[Brief description of the drawings]
FIG. 1 is a drawing for explaining one embodiment of the present invention, which relates to the molded product of FIG.
FIG. 2 is a view for explaining a detailed embodiment in one embodiment of the present invention.
FIG. 3 is a drawing illustrating the shape of a product (powder molded product).
FIG. 4 is a diagram illustrating the general principle of powder molding.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Die, 20 ... Lower punch, 30 ... Core rod, 40 ... Upper punch 51 ... Die plate, 70 ... Chute, 71 ... Bracket 60 ... Feeder, 61 ... Powder supply port, 62 ... Drive rod, 63 ... Support member 81 ... Holding plate, 82: guide rod, 83: compression spring, 84: nut.

Claims (4)

In a powder molding machine configured to move the molded product extruded from the die to the chute 70 provided at the end of the die plate at the leading edge of the feeder 60 reciprocating on the die plate 51, the molded product is opposed to the feeder 60. A holding plate 81 for restraining and holding the molded product is provided so as to be able to advance and retreat with the operation of the feeder, and the feeder 60 is advanced to a position where the lower end of the molded product is separated from the die plate 51, and at the same time as the retreat starts, the molded product is started. Characterized in that the device is released from the restraint and moves to the chute 70. The powder molding according to claim 1, wherein the means for supporting the pressing plate (81) so as to be able to move back and forth is a guide rod (82) and a compression spring (83) sliding horizontally through the chute (70) or a bracket (71) connected to the mount. Product unloading device in the machine. The molded product unloading device according to claim 1, wherein the means for moving the holding plate (81) is a hydraulic or pneumatic cylinder provided on a chute (70) or a bracket (71) connected to the mount. The molded product unloading device in a powder molding machine according to claim 1, wherein a support member 63 having a recess adapted to the shape of the molded product is attached to a front edge of the feeder 60.

Images