JPH0790317B2 - Extrusion molding equipment for forged parts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to extrusion of a forged part used in a sizing step performed to improve the processing accuracy of the outer peripheral surface of a rough member formed by hot forging or warm forging. The present invention relates to a molding device.

(Prior Art) Since forged parts are tough and reliable, they are widely used in major mechanical parts such as engines and gears.

There are hot forging, warm forging, and cold forging in the forging parts processing method, and hot forging is usually performed in the temperature range of 800 ℃ ~ 1300 ℃, and the shape of the processed product depends on the workability of the material. It is widely used because of its unlimited size. Cold forging is performed at room temperature and has advantages such as high productivity and increased component strength. In addition, warm forging is a temperature range that is higher than the temperature range of cold forging in order to shorten the process and enable the processing of large parts, and in addition to the temperature range of hot forging in order to improve dimensional accuracy. It is carried out for the purpose of processing in the intermediate temperature range (500 ° C to 800 ° C) where both are low.

By the way, when manufacturing workpieces such as gears, in addition to the method of temporarily forging the material into a substantially cylindrical shape, grinding the outer periphery with a hobbing machine, shaving to obtain a finished product, Obtain a rough member that has been subjected to tooth formation,
After that, in order to improve the accuracy of the outer dimension, the rough-shaped member is ground by a hobbing machine during cold and shaving is performed to obtain a finished product. However, in such a method, forging is performed while hot or warm, so that the obtained rough member causes heat shrinkage, resulting in poor dimensional accuracy and grinding with a hobbing machine to obtain a finished product. It was necessary to perform sufficient processing.

Therefore, after obtaining a tooth-shaped molded rough member by hot or warm forging, in order to improve the dimensional accuracy of this rough member, sizing is performed using an extrusion molding device during cold, , A method of eliminating grinding with a hobbing machine to improve productivity and processing accuracy has been proposed, and an example of the method has been proposed by the applicant of the present invention to produce a warm or hot forged part (Showa 63 (Patent application submitted on November 11, 2014)
Is disclosed in the specification and drawings.

Here, in the hot forging step, a rough member is formed,
In the lubrication process, the metal soap layer is formed on the surface of the rough-shaped member, and then it is supported on the lower die mount side of the press in the sizing process in the cold state and at the center of itself. The outer peripheral surface of the rough member is ground by using a die in which a cutting blade for grinding the outer peripheral surface of the rough member is formed on the inner peripheral wall of the processed hole.

That is, in this sizing process, the outer peripheral surface of the rough member is ground during cold by the cutting blade of the central processing hole of the die to ensure a predetermined dimensional accuracy. By this processing, molding is performed so as to maintain the processing accuracy of the rough-shaped member within the allowance in the shaving processing that will be performed later.

According to such a processing method, productivity can be increased. Moreover, in such a cold sizing process, if the dimension of the cutting edge of the die is secured to the required accuracy, the outer peripheral surface of the workpiece is also formed with the required processing precision.

(Problems to be Solved by the Invention) By the way, the external dimensions of a molded product such as a gear manufactured in this manner depend on the dimensional accuracy of the cutting edge of the die used in the sizing process.

However, the ambient temperature of the die in the extrusion molding apparatus changes depending on the season and the like. Therefore, when the dimension of the die, that is, the cutting edge, such as the pitch circle, changes according to the increase or decrease in temperature according to the ambient temperature, the outer dimension of the workpiece also increases or decreases. For example, according to the measurement by the present inventor, a relatively large spur gear (when the outer shape is about 100 mm) causes a deviation of 1 μ per 1 ° C. of temperature.

Further, when the molded product is mounted at a predetermined position after completion, it may be desirable to slightly increase or decrease the outer shape thereof depending on the relative positional relationship with other members facing each other.

In this way, when it is necessary to finely adjust the dimensional deviation of the cutting edge due to the ambient temperature in adjusting the dimension of the molded product to the standard dimension, or when the external dimension of the molded article is compared with the standard dimension. In some cases, it may be necessary to increase / decrease and finely adjust the molding.

For this reason, it is necessary to finely adjust the outer dimensions of the cutting edge of the die by, for example, about 0.1 mm to 0.2 mm from the reference value.

However, conventionally, when the outer shape of the molded product is adjusted to be increased or decreased as necessary, it is necessary to newly manufacture a die having desired dimensional accuracy, which is a cost problem.

An object of the present invention is to provide an extrusion molding apparatus for a forged component that can maintain the dimensional accuracy of a molded product at a desired amount by finely adjusting the outer dimensions of the die itself used for sizing.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a press for performing a pressurizing operation by bringing the respective mounting bases of the upper die and the lower die into contact with each other, and mounting the lower die of the press. The die is supported on the table side and has a cutting edge for grinding the outer peripheral surface of the rough member formed on the inner peripheral wall of its own central processing hole, and is separately supported by each of the upper die and lower die mounts. In the extrusion molding apparatus for a forged component for sizing the rough-shaped member sandwiched by a pair of sandwiching members for sandwiching the rough-shaped member from above and below, a position facing the processed hole of the die. A heater for heating, a temperature sensor for detecting the temperature of the die heated by the heater, and a die temperature setting means for designating a desired temperature by the temperature of the die to finely adjust the dimensions of the die. , Above die temperature A heater drive circuit for supplying electric power to the heater based on the temperature designated by the setting means and the temperature information from the temperature sensor to control the die so as to maintain the die at the designated temperature, and the die temperature and the thermal expansion of the die in advance. A storage circuit for storing correlation data with a die size value based on the above.

(Operation) Since the heater heats the die and the heater driving means can keep the die at a required temperature, the die is thermally expanded and contracted by an amount corresponding to the temperature, and its outer dimension is adjusted to be increased or decreased. The rough-shaped member ground by the cutting blade of is formed into a molded product having desired dimensional accuracy.

(Example) The extrusion molding apparatus for forged parts shown in FIG. 1 manufactures a spur gear G as a molded product. Note that FIG. 2 shows a state in which the right half of the rough-shaped member A to be described later is not subjected to the sizing processing, and the left half is in a state after the sizing processing.

Here, the rough-shaped member A of the spur gear G is previously prepared by hot forging.
Is molded in advance, and the rough-shaped member A supplied therefrom is subjected to a sizing process in an extrusion molding device for a forged part to obtain a spur gear G which is a molded product.

The forging device used here may be a well-known one, and an example thereof is disclosed in the above-mentioned method for manufacturing warm or hot forged parts (patent application filed on November 11, 1988).

Such a forging device compresses a heated material from above and below, thereby forming a tooth profile Aa on the outer peripheral portion and a rib Ab having an I-shaped radial cross section inside the tooth profile Aa. What is configured to mold the rough member A is used.

As shown in FIG. 1, the extrusion molding apparatus for forged parts generally has a structure as a press 1, and relatively moves the upper die 2 and the lower die 3 in the vertical direction. In particular, an upper die 2, a lower die 3, a hydraulic cylinder 4 for raising and lowering the upper die 2, a pair of guides for supporting the upper and lower ends of the upper and lower base frames and guiding the upper die 2 respectively. It comprises a shaft 5, a heater 7 for heating the die 6 in the lower die 3, and a heater driving means 8 connected to the heater 7.

The upper die 2 is connected to the piston of the hydraulic cylinder 4 and has an upper mount 9 whose both ends are slidably supported by the guide shaft 5, and an upper clamp whose upper end is integrally supported by the upper mount 9. The upper punch 10 as a member.

On the other hand, the lower die 3 is supported by the lower mount 11 fixed to the lower base frame of the press 1, the lower punch 12 as a lower holding member supported by the lower mount 11, and the lower mount 11. The tooth profile Aa of the outer peripheral surface of the rough member A (second
(See the drawing), the die 6 is formed with a cutting blade 14 having an inner tooth shape slightly larger than the tooth profile Aa.

The upper and lower punches 10 and 12 move up and down in the central processing hole 13, and the lower punch 12 is provided with a compression spring 18 at the lower part thereof so as to be able to move up and down. Moreover, both punches 10,12
The outer diameter is determined such that the outer peripheral dimension of the end is somewhat smaller than the valley of the tooth profile Aa of the rough member A so as not to interfere with the cutting blade 14 while holding the rough member A. ing. In this case, the rib Ab of the rough member A is formed in an I-shaped cross section.

The upper and lower punches 10 and 12 have convex end portions that engage with the annular recesses A1 and A2 on the upper and lower side surfaces of the rough member A, and these end surfaces are formed by the forging die used in the forging process. The upper surface (or at least the same as the outer peripheral portion) of a certain lower die and the lower surface of the upper die are formed in substantially the same shape.

The right side of FIG. 2 is a state in which the rough member A is sandwiched between the upper punch and the lower punch and is inserted into the guide tooth portion 141, and the left side is the right state in which both punches 10 and 12 are moved downward. The state of the rough-shaped member A after moving and passing the cutting blade 14 and sizing the tooth profile is shown.

As shown in FIG. 2, on the inner peripheral wall of the central processing hole 13 of the die 6, there is formed a guide tooth portion 141 having an inner tooth shape slightly larger than the tooth profile Aa from the upper position, and a tapered portion extending downward by this. 142
And a cutting blade 14 that extends downward and thereby substantially forms the tooth profile Aa are sequentially formed.

Here, when the die 6 is processed at room temperature (20 ° C.), the pitch circle diameter Dp, which is one of the outer dimensions of the cutting blade 14, is formed.
Is smaller than the reference pitch circle diameter Dpa by a required amount −Xμ. That is, in order to match the pitch circle diameter Dp of the die 6 with the reference pitch circle diameter Dpa, the heat expansion treatment described later is required.

As shown in FIG. 2, the die 6 is formed with an annular groove 15 on the lower surface side of the die 6 at a position surrounding the central processing hole 13, the heater 7 is fitted therein, and moreover, the main portion of the die 6 is formed. Is equipped with a temperature sensor 16 for detecting the temperature of the die 6 heated by the heater.

The heater 7 here is configured as a metal lock heater in which a heating element (sheath heater) is housed in a cylindrical metal case, and its lead wire 701 is connected to a heater drive circuit 804 in the controller 8. Further, the temperature sensor 16 is configured to input the temperature information to the input / output circuit 803 in the controller 8. Reference numeral 17 indicates a temperature designation switch as die temperature setting means for inputting designated temperature information to the controller 8.

The controller 8 includes a control circuit 801, a storage circuit 802 in which a predetermined temperature control program (see FIG. 4) is written,
An input / output circuit 803 that receives an input signal and outputs a control signal
And the heater drive circuit 804 and the A / D converter 805 described above.

The operation of such an extrusion molding apparatus for forged parts will be described together with the step of manufacturing a spur gear G as a molded product (see FIG. 5).

First, the case hardened steel as a raw material is heated to a predetermined temperature (about 1250 ° C.), and is primarily formed into a substantially forging shape. Further, the primary-molded material is put between the female die and the male die of the forging device (not shown) and compressed, whereby the outer periphery of the tooth profile is larger than that of the completed tooth profile Aa by a required amount and the center of the tooth profile is larger. Spur gear G with rib Ab
The rough-shaped member A for use is secondarily formed, and the hot forging step is completed.

Then, a metal soap layer is formed on the surface of the rough member A.

That is, the rough member A is sequentially dipped from the zinc phosphate solution into the sodium stearate solution to form a zinc stearate layer on the surface of the rough member A. As a result, a metallic soap layer is formed on the surface of the rough member A, and the lubrication process step is completed.

After this, the sizing process is performed.

In this case, the designated temperature information Tx is already input to the controller 8 from the temperature switch 17, and the heater is driven so as to hold the die 6 at the designated temperature Tx. That is, here the control circuit
The control unit 801 takes in the temperature information T from the temperature sensor 16 and the designated temperature Tx information from the temperature designation switch 17 as shown in the control flow of FIG. 4, compares the two values, and eliminates the deviation. , And outputs an output for driving the heater 7.
The heater drive circuit 804 supplies drive power to the heater 7 and increases or decreases the temperature of the die 6 according to the control signal. Incidentally, here, the die 6 is not equipped with the forced cooling means,
The cooling means is simply replaced by utilizing the natural cooling effect of heat radiation to the atmosphere. However, in some cases, forced cooling means such as cooling water circulation means may be installed.

Here, it is assumed that the spur gear G is formed to have a standard size, and the pitch circle diameter Dp of the cutting blade 14 of the die 6 is maintained at the standard pitch circle diameter Dpa.

Therefore, for example, based on the approximate table of FIG. 6, the reference temperature Ta (here, 80 ° C.) for obtaining the die ambient temperature to obtain the reference pitch circle diameter is determined as the designated temperature Tx.

In addition, when it is desired to increase or decrease the external dimensions of the spur gear G from the reference diameter, the pitch circle diameter Dp of the die 6 is changed to the reference pitch circle diameter Dpa.
In order to further increase or decrease, the temperature value is obtained based on the rough calculation table of FIG. 6, and the designated temperature information is input to the controller 8 by the temperature designation switch 17. The estimation table of FIG. 6 used here is prepared in advance for each device.

The rough-shaped member A is set in the extrusion molding apparatus for the forged component held in such a state. That is, the rough member A is held by the upper and lower punches 10 and 12, and is passed downward from above with respect to the cutting blade 14 of the die, and a portion other than a desired size (for example, 0.2 mm to 0.5 mm around the tooth profile Aa) is held. To a tooth profile Ba and the sizing process is completed.

After the sizing process, the spur gear G is taken out from the lower part of the lower mold 3, the burrs on the upper surface of the tooth profile Ba are removed, and the next shaving process is started.

In this shaving step, the spur gear G is completed by being applied to a well-known shaving apparatus, polishing a predetermined amount of the margin of the tooth profile Aa, and also performing a curved treatment in the tooth width direction.

As described above, the extrusion molding apparatus for forged parts shown in FIG. 1 heats the die to the required temperature by the heater when the spur gear G having the standard size is manufactured, and thermally expands the die by an amount corresponding to the temperature, The pitch circle diameter Dp of can be easily fine-tuned to the reference pitch circle diameter Dpa. Therefore, the external dimension accuracy of the spur gear G can be easily and finely adjusted to a desired amount.

The above-mentioned extrusion molding apparatus for forged parts has been used for sizing the outer peripheral tooth portion of the spur gear G, but in addition to this, the present invention can be applied to, for example, dies of various drawing molding apparatuses. Fine adjustment of the external dimensions of the molded product can be easily performed.

(Effects of the Invention) As described above, according to the present invention, the die is heated to the required temperature by the heater,
Since the die can be thermally expanded and contracted to increase or decrease the outer dimensions of the die, the dimensional accuracy of the molded product obtained by sizing the rough material with the cutting edge of its central processing hole can be easily adjusted to the desired amount. It has the effect of being retained.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an extrusion molding apparatus for forged parts as one embodiment of the present invention, and FIG. 2 is a die portion of the same molding apparatus, in particular, before sizing a rough-shaped member on the right side and after processing on the left side. FIG. 3 is an enlarged cross-sectional view shown in FIG. 3, FIG. 3 is a plan view of a die portion of the molding machine of FIG. 1, and FIG. 4 is a flow chart of a control program executed by a controller in the molding machine of FIG. FIG. 6 is a manufacturing process diagram of a spur gear G including a sizing process using the device of the present invention, and FIG. 6 is a die temperature-increasing / decreasing amount characteristic diagram of the cutting edge of the molding device of FIG. 1 ... press, 2 ... upper mold, 3 ... lower mold, 6 ... die,
7 ... Heater, 8 ... Controller, 9 ... Upper mount,
10 …… Upper punch, 11 …… Lower mount, 12 …… Lower punch, 13
…… Central processing hole, 14 …… Cutting blade, A …… Coarse shaped member, Aa…
… Tooth profile, G… Spur gear.

Claims (1)

[Claims] 1. A press for pressurizing the upper and lower dies by contacting and separating the dies, and a press supported by the lower die pedestal side of the press and on the inner peripheral wall of its own central processing hole. A die formed with a cutting blade for grinding the outer peripheral surface of the rough member, and a pair of clamping members that are separately supported by the upper and lower mounting bases and clamp the rough member from above and below. In the extrusion molding apparatus for a forged component for sizing by pressing the rough shaped member into the central processing hole, a heater provided at a position facing the processing hole of the die, and a heater heated by the heater From a temperature sensor that detects the temperature of the die, a die temperature setting unit that designates a desired temperature by the temperature of the die to finely adjust the dimensions of the die, and a temperature designated by the die temperature setting unit and the temperature sensor. Temperature A heater drive circuit that supplies electric power to the heater based on information to control the die so as to maintain it at a specified temperature, and a memory that stores the correlation data between the die temperature and the die dimension value based on the thermal expansion of the die in advance. An extrusion molding apparatus for forged parts, comprising: a circuit.