JPH0421616Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention is a flat die type that performs a prescribed rolling process on the outer circumferential surface of a rolled object by rotating the object while pinching it with a pair of flat dies. The present invention relates to rolling machines, and particularly to techniques for improving the processing accuracy of rolled products.

BACKGROUND TECHNOLOGY AND PROBLEMS In general, a flat die type rolling machine sandwiches a shaft-shaped workpiece between a pair of opposing flat dies, and at least one of the flat dies is moved linearly. The object to be rolled is relatively rolled between a pair of flat dies to perform rolling forming on the outer peripheral surface. During the rolling process, these flat dies receive a rolling reaction force that moves them away from each other from the object to be rolled, so in order to absorb the rolling reaction force, the pair of flat dies are sandwiched between them. Usually, frame members are arranged on both sides in the clamping direction, and these frame members receive the rolling reaction force applied to the flat die during rolling. For example, in the 1970s
This is the rolling machine described in No. 99243.

Conventionally, in this type of flat die rolling machine, a reinforcing tie bar or the like is provided across the frame members to support the longitudinal middle part of the frame member from the outside and restrain it, thereby preventing deflection in the direction of separation. Although attempts have been made to suppress this, it is still unavoidable that the frame member deflects outward due to the rolling reaction force during rolling, which is one of the causes of variations in the dimensions of rolled products.

On the other hand, it is possible to restrain the frame members with a preload on the flat die side, but if too large a preload is applied in the direction of approach of the frame members, the amount of inward deflection of the frame members will increase. Therefore, there is a limit to the setting of such a preload, and for this reason, it has been difficult to obtain a precision rolled product, particularly a rolled product that requires accuracy on the order of microns.

Means for Solving the Problems Against the background of the above-mentioned circumstances, the present invention was made in order to obtain a flat die type rolling machine that enables high-precision rolling forming regardless of rolling reaction force. The gist of this is that the objects to be rolled can be moved relative to each other in directions parallel to each other in order to perform a prescribed rolling process on the outer peripheral surface of the object by rolling the object while squeezing it. A pair of flat dies provided,
A pair of columnar frame members connected to each other at both ends and arranged parallel to each other on both outsides of the pair of flat dies in order to receive the rolling reaction force from the rolled product applied to the pair of flat dies. A flat die rolling machine comprising: (a) an axial hole for accommodating a shrinking heater, which approaches a longitudinally intermediate portion of the pair of columnar frame members; (b) a block member that is sandwiched between longitudinally intermediate portions of the pair of columnar frame members and supports the fastening load applied by the fastening bolt; There is a particular thing.

By doing this, an extremely large fastening load is applied to the longitudinal intermediate portion of the pair of frame members of the flat die rolling machine by shrinkage tightening with the fastening bolts, and the Since the fastening load is supported by the block members, even if the rolling reaction force that occurs during rolling is applied, the deflection of the columnar frame members is suppressed, dramatically improving the accuracy of the rolling-molded products. It will be done. In addition, there is no need to increase the size of the rolling machine in order to increase the rigidity of the columnar frame member, and moreover, a large fastening load is applied to the columnar frame member in opposition to the rolling reaction force, which reduces the deflection of the frame member. This occurs due to the pulsating rolling reaction force. Vibration and noise during rolling are officially suppressed.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail based on the drawings.

FIG. 1 is a front view of a flat die type rolling machine 10 which is one embodiment of the present invention, and 12 in the figure is a base. On this base 12, a pair of guide frames 14 in the shape of thick plates are mounted as frame members.
14 are erected to face each other in parallel at a predetermined distance apart, and these guide frames 14
The upper ends of the two are connected to each other by a connecting frame 16, forming a gate shape. In addition, as is clear from FIG. 2, spacer blocks 18 and 20 as block members are respectively incorporated in the direction in which these guide frames 14 face each other, and the guide frames 14 and 14 are connected to each other by long bolts, which will be described later.
It is integrated with.

Flat T-shaped guide protrusions 22 are formed along the longitudinal direction on the inner surfaces of each guide frame 14 facing each other, and these guide protrusions 22 allow the sliders 24, 24 to be parallel to each other. It is adapted to be slidably guided in each direction. Each slider 24 is
A flat T-shaped groove 2 fitted into the guide protrusion 22
6, and the opposite side has a flat die 2
A pair of flat dies 28, 28 are opposed to each other at a predetermined distance apart, and each slider 24, 24 moves the flat dies 28, 28 in a direction parallel to each other. It is now possible to move relative to

As is clear from FIG. 1, piston rods 34, 34 of hydraulic cylinders 32, 32 fixed to the connection frame 16 are connected to one ends of these sliders 24, 24, respectively. These hydraulic cylinders 32 are moved in opposite directions via each slider 24, for example, one flat die 28 is moved downward in FIG. 1 while the other flat die 28 is moved upward. It's starting to work. Furthermore, as is clear from FIG. 2, racks 36, 36 are respectively fixed to both sliders 24, 24 along the direction of movement thereof, and a synchronizing pinion 38 is engaged with both of these racks 36. is provided. This pinion 38 is rotatably supported by the spacer block 20 via a bearing 42 by a rotating shaft 40, and serves to synchronize the reciprocating movements of both flat dies 28 in mutually opposite directions via sliders 24, 24. fulfill.

Between the flat dies 28 that are reciprocated in this manner, a shaft-shaped rolled object W having a diameter slightly larger than the interval between them is arranged. The object W to be rolled is rolled relatively while being pinched by the pair of flat dies 28 without changing its concentric position with respect to the pinion 38 due to the synchronous reciprocating motion of the pair of flat dies 28. It is rotatably supported around its axis by center support rods 44 and 46 at both ends. A pushing force is applied to the center support rod 44 by a cylinder (not shown) in the direction of pushing the rolled object W between both flat dies 28 from the side, while the center support rod 46 on the opposite side It slidably passes through the shaft 40, and is retracted by a cylinder (not shown) in synchronization with the push-in.
As a result, the axially rolled workpiece W is gradually sent in the axial direction while being rolled under pressure by both flat dies 28, so that although the rolling width of the flat dies 28 itself is relatively narrow, For example, a spline or the like is rolled over a wide range in the axial direction of the object W to be rolled.

During such rolling forming, both flat dies 28 receive a rolling reaction force from the object W to be rolled in a direction that separates them from each other, and the rolling reaction force passes through the die holder 30 and the slider 24 to the pair of guide frames. Received by 14. In other words, these guide frames 14 are arranged on both sides of the pair of flat dies 28 in the pressing direction, and receive the rolling reaction force with the wide end surfaces (top surfaces) of the guide protrusions 22. This reaction force is applied in a direction that separates both guide frames 14 from each other.

Between these guide frames 14, 14 is spacer block 1, which is a block member, as described above.
8 and 20 are inserted. These spacer blocks 18 and 20 are located on both sides of the sliders 24 and 24 in the width direction, and are located on both sides of the sliders 24 and 24 in the width direction.
4 and 14, and as is clear from FIG. 1,
Both are located at the middle portion of the guide frame 14 in the height direction.

As is clear from FIG. 3, it passes through both guide frames 14 and the spacer blocks 18, 20 interposed therebetween.
A total of four long bolts 48 (two in total) are provided (see FIG. 4), and by tightening nuts 50 on each bolt 48, both guide frames 14 are connected to each other through spacer blocks 18 and 20. The long bolt 48 and nut 50 constitute a fastening means. These long bolts 48 are inserted through the guide frame 1 in a direction parallel to the opposing direction of the pair of flat dies 28.
4 and 14 are fastened in a direction that produces a fastening load in the direction of approaching each other. In other words, while compressing the spacer blocks 18 and 20, a fastening load is generated in the direction opposite to the direction of action of the reaction force during rolling, and the rolling reaction force causes the guide frame to
4 and 14 from being bent outward. Moreover, these long bolts 4
8 and the nut 50 is set to a magnitude that maintains the squeezing force on the spacer blocks 18, 20 regardless of the rolling reaction force, and in particular in this embodiment, it is set to a magnitude greater than the rolling reaction force. ing.

In order to generate such a fastening load, each long bolt 48 is provided with an axial hole 52 that penetrates in the axial direction. For example, insulated heating wires are inserted as heater means into these axial holes 52, and each long bolt 48 is heated and thermally expanded in the axial direction, and then each nut 50 is tightened and cooled. Each bolt 48
As a result of contraction in the axial direction, a fastening load larger than the rolling reaction force is generated. This is so-called heat-tightening, and a preload of several tens of tons, for example, is applied, which is an order of magnitude larger than that of conventional equipment.

By the way, the accuracy of rolled products is determined by guide frame 1.
4 and 14, and it can be said that this deflection immediately determines the accuracy of the product. It is desirable to manufacture the left and right guide frames 14, 14 in one piece, but it is structurally difficult. However, if the guide frames 14, 14 are fastened with each long bolt 48 pinching the spacer blocks 18, 20 with a force greater than the rolling reaction force, as described above, the pinching state will not be reversed. This is maintained regardless of the action of the reaction force, and outward deflection of the guide frames 14, 14 is suppressed, resulting in a frame rigidity close to that of an integral structure.

This is due to the following reason.

In the above-mentioned fastened state, the bolt 48 is elastically stretched in the axial direction, and the spacer blocks 18, 2 are compressed by the fastening.
When viewed microscopically, 0 can be seen as equivalent to an extremely rigid compression spring, and elastic compressive strain (contraction) is generated by the above-mentioned pinching pressure. Now, as shown in FIG. 5a, if we conceptually look at the state where the bolt 48 is tightened and no rolling reaction force is generated, the block 18 and the bolt 48 are subjected to an equal and opposite internal force Pi (the bolt 48 has tension,
Block 18 is balanced by compression). This internal force Pi is the fastening load by the bolt 48 (however, for ease of understanding, we will focus on only one side).

Assuming that the spring constant of the bolt 48 is Kb and the spring constant of the block 18 is Kc, when the rolling reaction force P acts as shown in Fig. 5b, the force Pb in the tensile direction added to the bolt 48 is If the elongation due to the reaction force is δ (exaggerated for convenience of explanation), then Pb=Kbδ...(1).

Further, the compressive force Pc lost from the block 18 due to the decrease in the clamping force of the bolt 48 is Pc=Kcδ (2). Then, from the force balance relationship, P=(Pi+Pb)-(Pi-Pc) =Pb+Pc=(Kb+Kc)δ ∴ δ=P/(Kb+Kc)...(3). By substituting this δ into equation (1), it can be expressed as Pb=[Kb/(Kb+Kc)]·P (4).

That is, even if the rolling reaction force P acts on the tightened bolt 48, the internal force Pb in the tensile direction added to the bolt 48 itself is not the reaction force P itself,
It is discounted based on the relationship in equation (4).

FIG. 6 shows this relationship graphically.
The horizontal axis represents the elongation of the bolt 48 and the contraction of the block 18, and the vertical axis represents the load, and the point P=0 represents the state at the time of fastening (FIG. 5a). And rolling reaction force P
In the state where this occurs, only a portion Pb of the reaction force P acts on the bolt 48 as described above, and the elongation due to the force Pb is also suppressed to δ.

On the other hand, if there is no block, for example, if the guide frames 14, 14 are held together and fastened using fastening means such as tie bars (equivalent to bolts), the rolling reaction force will be applied directly to the bolts (or tie bars). It acts as P ₂ , and the elongation associated with it is quite large, δ ₂ . This results in the amount of outward deflection between the guide frames 14, 14, in other words, the variation in the distance between the pair of flat dies 28, 28, but according to this embodiment, such variation in the distance is greatly reduced. Therefore, high-precision rolling is possible. In particular, as in the present embodiment, the rolled workpiece W is gradually pushed from the side between the flat dies 28, 28, and the axially equivalent When rolling is performed over a wide area, the reaction force generated during rolling becomes quite large, but by adopting a fastening structure like this example, rolling can be performed regardless of this rolling reaction force. Variations in the dimensional accuracy of shaped products can be kept to a small level, and even cases where precision on the order of microns are required can be easily handled.

Incidentally, according to an experiment by the inventor of the present invention,
For example, when rolling a 20 mmφ rolled object W, a rolling reaction force of about 20 tons is generated, so if the columnar guide frames 14, 14 alone support the rolling reaction force, the guide frames 14, 14 is 5/
Whereas it was difficult to obtain a highly accurate rolled product due to the occurrence of a deflection of about 100 mm, the rolling machine of the embodiment of the present application has a long bolt 48 for shrink tightening and spacer blocks 18, 20. Since an order of magnitude larger fastening load was applied to the intermediate portions of the guide frames 14, 14 in the longitudinal direction, the deflection due to the rolling reaction force was only a few microns, and a highly accurate rolled product was obtained.

In addition, as described above, according to the rolling machine of this embodiment, the deflection caused by the incomparably large fastening load applied to the intermediate portions in the longitudinal direction of the guide frames 14, 14 by shrinkage tightening is reduced. As a result, in connection with the pulsating rolling reaction force, the guide frames 14, 14
The noise generated by the rolling machine is suppressed by reducing the vibrations generated in the rolling machine. Incidentally, according to the inventor's experiments,
While the noise during rolling of the conventional rolling machine was 80 decibels, the noise during rolling was 75 decibels or less with the rolling machine of this embodiment.

Furthermore, if an attempt is made to increase the rigidity of the rolling machine frame itself, such as the guide frames 14, 14, in order to achieve rolling accuracy on the order of microns, the rolling machine of this embodiment will have an extremely large external size. According to the rolling machine, there is no need for the guide frames 14, 14 themselves to be members with a large cross section, so there is an advantage that the rolling machine can be made smaller.

Furthermore, as is clear from Fig. 6, the bolt 18
The effect of suppressing the elongation δ of blocks 18 and 20
The fastening load Pi by the bolt 18 does not necessarily need to be set larger than the rolling reaction force P, but the rolling reaction force P also prevents the block from being blocked. It is necessary to set the clamping force to 18, 20 so that it does not disappear.

Further, in the embodiment described above, the pair of flat dies 28, 28 are configured to reciprocate in the vertical direction via the sliders 24, 24, but even if the pair of flat dies 28, 28 are configured to be reciprocated in the horizontal direction, often,
Alternatively, one of the sliders 24 may be fixed and the other may be moved back and forth. moreover,
It is applicable not only to a structure in which the flat dies 28, 28 are repeatedly moved back and forth and the object to be rolled is pushed in from the side, but also to a type of rolling machine in which a predetermined rolling is performed by a single, unidirectional relative movement. , the present invention can be effectively applied. Although not illustrated in detail, it goes without saying that the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a front view of a flat die rolling machine which is an embodiment of the present invention, and FIGS. 2 and 3 are a sectional view and a sectional view, respectively, of FIG. 4 is a right side view of the rolling machine shown in FIG. 1, and FIG. 5 is an explanatory diagram conceptually showing a part of the fastening section shown in FIG. 3. FIG. 6 is a graph representing the fastening characteristics of the fastening portion shown in FIG. 5. 10... Flat die type rolling machine, 14... Guide frame (frame member), 18, 20... Spacer block (block member), 48... Long bolt (fastening bolt), 52... Axial hole.

Claims (1)

[Claims for Utility Model Registration] A pair of objects that are movable relative to each other in directions parallel to each other in order to apply a predetermined rolling process to the outer peripheral surface of an object to be rolled by rolling the object while pinching the object. flat dies, and are arranged parallel to each other on both outer sides of the pair of flat dies with their ends connected to each other in order to receive the rolling reaction force from the object to be rolled applied to the pair of flat dies. A flat die rolling machine is provided with a pair of columnar frame members, and the machine is provided with an axial hole for accommodating a heater for shrinkage tightening, in a longitudinally intermediate portion of the pair of columnar frame members, A fastening bolt that applies a fastening load in a direction in which they approach each other by shrinkage tightening, and a block member that is sandwiched between longitudinally intermediate portions of the pair of columnar frame members and supports the fastening load applied by the fastening bolt. This flat die type rolling machine is characterized by: