JPH0541360B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a hydraulic powder compacting press device for producing a powder compact by pressure compacting metal powder, and in particular, a hydraulic powder compacting press device for reducing weight variation of filled powder, The present invention relates to a technology for applying an underfill filling method to a hydraulic powder molding press device in order to improve product accuracy.

(Prior Art) Conventionally, in a powder forming press device for pressure forming metal powder, metal powder is filled into a cavity defined by a die, a lower punch, and, if necessary, a core rod. The metal powder inside the cavity is pressure-formed using a punch, and during powder molding,
When the upper punch descends and comes into contact with the powder filled in the cavity, the filled powder scatters or overflows onto the die, reducing the powder weight of the compact and causing product variations. be. This phenomenon is particularly noticeable when the upper punch has a protrusion, and has become a major problem in the case of products with strict precision such as gears.

In order to solve this problem, in a mechanical powder forming press, a powder feeder fills the powder into the cavity, slides it over the die, scrapes off a predetermined amount of powder on the cavity, and then presses the powder onto the top of the die. is raised relative to the top surface of the powder in the cavity to position the top surface of the filled powder in the cavity below the top surface of the die, thereby bringing the descending upper punch into contact with the powder in the cavity at a position below the top surface of the die. This filling method is used as an underfill method.

Conventionally, in mechanical press molding equipment, in order to carry out the powder filling method using the underfill method described above, after filling the powder into the cavity, the lower punch is lowered by a predetermined amount using air pressure, and after the powder is formed, it is lowered by a cam. A common method is to return the punch to its original position.

As molding shapes become more complex in powder molding and methods to improve the functionality of presses become stronger, an underfill mechanism is required not only for mechanical press equipment but also for hydraulic press equipment. It was difficult to incorporate a mechanism similar to a mechanical press into the device.

(Problems to be Solved by the Invention) The present invention seeks to improve a hydraulic powder molding press apparatus so that an underfill method can be applied in order to eliminate weight variations in powder compacts and improve product precision. It is something.

(Means for Solving the Problem) Therefore, according to the present invention, as shown in FIGS. 1 and 2, upper and lower rams 1 and 2 operated by hydraulic pressure, and an upper a punch 3; a die 5 having a die hole 4 cooperating with the upper punch 3 and supported by the lower ram 2; In a hydraulic powder molding press device comprising a lower punch 8 inserted from the side to define a cavity 7 in the die hole 4, a lower base plate 9 is provided at a position below the upper base plate, and a lower tom 2 is attached to the lower base plate. An annular upper tooth member 11 is attached to the lower base plate concentrically with the lower ram 2, and has a plurality of upper teeth 10 spaced apart in the circumferential direction and arranged on the lower surface as a lift-up device for underfill. An annular lower tooth member 13 having lower teeth 12 on the upper surface which can mesh with the upper teeth 10 of the annular upper tooth member 11 is fixedly attached to the lower base plate 9 at a position below the annular upper tooth member 11. Means 14 for supporting and rotating the annular lower toothed member around the center axis of the lower ram 2 is provided, and a flange 15 for pushing up the lower toothed member is provided on the lower ram 2 at a position below the annular lower toothed member 13.

(Function) According to the above-described configuration, when the upper ram 1 is at the upper limit position as shown by curve A in FIG.
is raised from the product extraction position _b1 as shown by curve B, whereby the lower punch 8 is relatively lowered into the die hole 4 of the die 5 to form a cavity 7, and the flange 15 is attached to the annular lower tooth member 13. Due to the contact, the upward movement of the lower ram 2 is temporarily stopped at position _b2 . During this rising process of the lower ram 2, a feeder (not shown) operates as shown by curve C to supply and fill the cavity 7 with metal powder, and the feeder slides on the upper surface of the die 5 to fill a predetermined filling amount. After being worn out on the cavity 7, for example, as shown in FIG. 3, a hydraulic cylinder 30 connected to a hydraulic circuit shown in FIG. The lower tooth member 13 is operated by
by rotating the tooth 12 of the annular upper tooth member 11.
As shown in FIG. Then,
The lower ram 2 is raised to position b ₃ , whereby the upper surface of the metal powder in the cavity 7 falls below the upper surface of the die 4 and becomes underfilled, and the upper ram 1 is raised to position a ₁
The upper punch 3 presses and forms the metal powder in the cavity 7 with the lower punch 8 as shown in FIG.

As shown in FIG. 6, in the compression process, when the powder is pressure-molded by lowering the upper punch 3,
Due to the frictional pressure between the powder and the die 5, the die 5 and the lower ram 2 move downward as pressure is applied, the upward pressure applied to the lower tooth member 13 is released, and the teeth 12 of the lower tooth member 13 are moved to the upper tooth member 11. Separated from tooth 10. After the powder compaction is completed and the green compact is extracted from the die 5, the hydraulic cylinder is operated again to move the tooth tips of the upper and lower tooth members to opposing positions in preparation for powder filling.

The tooth profile of the upper and lower tooth members is preferably an angular tooth profile having an inclination angle so that the tips of the teeth can stably abut each other when the flange is pushed up.

In this way, the operation of the lower ram can be hydraulically controlled to perform underfilling.

(Embodiment) Figures 1 to 3 show one embodiment of the present invention, and in the illustrated example, upper and lower rams 1 and 2 of hydraulic cylinder devices 20 and 21 operated by hydraulic pressure,
an upper punch 3 attached to the upper punch 3; a die 5 supported by four support rods 23 via a T-shaped joint 22 at the upper end of the lower ram 2; Fixed lower punch 8 mounted on upper base plate 6 fixed in position
A hydraulic press device in which a cavity 7 is defined by a die hole 4 of a die 5, a lower punch 8 inserted into the die hole 4 from below, and a core rod provided as necessary. A lower base plate 9 is fixedly provided at a predetermined position on the base 24 at a position below the upper base plate, and the lower ram 2 passes through the center through hole 25 of the lower base plate 9 so as to be freely vertically moved.

A large diameter hole 26 is provided at the bottom of the through hole 25 of the lower base plate 9, and a plurality of protrusions or upper teeth 10 are arranged at equal intervals in the circumferential direction at an upper position within the large diameter hole 26. Annular upper tooth member 11 provided
is fixed to the lower base plate 9, and a plurality of protrusions or lower teeth 12 capable of meshing with the upper teeth 10 of the annular upper tooth member 11 are arranged on the upper surface at equal intervals in the circumferential direction. The tooth member 13 is supported in the large diameter hole 26 of the lower base plate 9 at a position below the annular upper tooth member 11 so as to be vertically movable and rotatable.
7 is provided, and the upper surface of the lower tooth member pushing-up flange 15 constituted by an adjustment nut provided on the lower ram 2 at a lower position of the annular lower tooth member 13 so that the vertical position can be adjusted comes into contact with the ball bearing 27. The lower tooth member 13 is allowed to freely rotate relative to the flange 15.

In the illustrated example, a pinion tooth 28 is formed on the outer periphery of the annular lower tooth member 13 as a means 14 for rotating the annular lower tooth member 13 around the center axis of the lower ram 2, and a rack 29 that meshes with the pinion tooth 28 is provided. A rack 29 is slidably provided on the lower base plate 9, and the rack 29 is actuated by a hydraulic cylinder device 30 to rotate the annular lower tooth member 13 through the pinion teeth 28, thereby rotating the lower tooth 12 provided on the upper surface of the annular lower tooth member 13 into an annular shape. Positioned between the upper teeth 10 provided on the lower surface of the upper tooth member 11, the lower tooth member pushing-up flange 15 pushes up the annular lower tooth member 13 and moves the lower teeth 12 between the upper teeth of the annular upper tooth member 11. In this way, the lower ram 2 is raised by a predetermined amount by hydraulic operation, and the upper surface of the powder filled in the cavity 7 is lowered by a predetermined amount from the upper surface of the die 5. ing.

FIG. 7 shows a hydraulic circuit that controls the rotation of the lower tooth member 13 by hydraulic pressure. When the feeder retreats, the solenoid 31 turns on, and the underfill hydraulic cylinder 30 retreats, causing the upper and lower tooth members 1
When the teeth 10 and 12 of No. 1 and 13 are positioned in a state where they can engage, and when they return to the origin, the solenoid 32 is turned on to advance the hydraulic cylinder 30, and the teeth 10 and 1
Position the two tooth tips so that they face each other. These operations are set to be synchronized with the press operations.

(Effects of the Invention) According to the present invention, it is possible to fill powder using the underfill method in a hydraulic powder molding press device in the same way as a conventional mechanical powder molding press device, and it is possible to perform powder compaction using a hydraulic powder molding press device. It has become possible to significantly improve product accuracy.

[Brief explanation of drawings]

FIG. 1 is a schematic front view showing a part of the hydraulic powder molding press device according to the present invention in cross section, FIG. 2 is an enlarged partial sectional view of the underfill lift-up device shown in FIG. 1, and FIG. A cross-sectional view of the underfill operating section taken along the - line in the figure in the direction of the arrow, Figures 4 to 6 are explanatory diagrams of the operation of the device shown in Figure 1, and Figure 7 is the underfill lift-up shown in Figure 2. It is a hydraulic control circuit diagram of the hydraulic cylinder device of the apparatus. 1... Upper ram, 2... Lower ram, 3... Upper punch, 4... Die hole, 5... Die, 6... Upper base plate, 7... Cavity, 8... Lower punch, 9... Lower part. Base plate, 10...upper teeth,
11... Annular upper tooth member, 12... Lower tooth, 13...
Annular lower tooth member, 14...Lower tooth member rotation means, 15
...Flange for pushing up the lower tooth member.

Claims (1)

[Scope of Claims] 1. Upper and lower rams operated by hydraulic pressure, an upper punch attached to the upper ram, and a die having a die hole that cooperates with the upper punch and supported by the lower ram,
In a hydraulic powder forming press device, the lower punch is fixed to the upper base plate located below the die and is inserted into the die hole from below to define a cavity in the die hole. A lower base plate is provided at the lower base plate, the lower ram is vertically penetrated through the lower base plate in a vertically movable manner, and an annular upper tooth member having a plurality of upper teeth spaced apart in the circumferential direction and disposed on the lower surface is connected to the lower ram. An annular lower tooth member concentrically fixed to the base plate and having lower teeth on the upper surface that can mesh with the upper teeth is rotatably supported by the lower base plate,
A means for hydraulically rotating the annular lower toothed member around the central axis of the lower ram is provided, and a flange for pushing up the lower toothed member is provided on the lower ram at a position below the annular lower toothed member. Hydraulic powder forming press equipment. 2. The press according to claim 1, wherein the hydraulic rotation means is constituted by a pinion tooth provided on the outer periphery of the annular lower tooth member, a rack meshing with the pinion tooth, and a hydraulic cylinder device connected to the rack. Device. 3. The lower tooth member is rotated by the hydraulic rotation means of the press device according to claim 1 so that the tooth tips of the upper and lower tooth members are placed in opposing positions, and then the lower ram is raised and the lower tooth member is pushed up by the flange. After filling the powder into the cavity of the die, the lower tooth member is rotated by a hydraulic rotating means to bring the teeth of the upper and lower tooth members into a position where they can engage, and the lower tooth member is pushed up by an amount corresponding to the height of the teeth to lower the lower ram. An underfill method for hydraulic press equipment in which the die rises as it rises, resulting in an underfill state.