JP2011115799A - Method of form-rolling rolled body or screw body, working device and formed body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of form-rolling, a working device and a formed body, wherein the generation of the staggers for performing the form-rolling of a form-rolled body or a screw body excellent in dimensional accuracy is reduced. <P>SOLUTION: In a method of form-rolling a form-rolled body, the relative position of a workpiece and a die is maintained on the target condition and the workpiece is form-rolled with the die by loading pushing force and/or pulling force between the workpiece and either of a die, the die mount of a structural member for supporting the die in synchronism with the rotation of the workpiece in the pushing position of an optional die. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rolling method, a processing apparatus, and a molded body for rolling a rolled body or a screw body. More specifically, a worm, a helical gear, a helical spline, a fixing screw used for a rolled body or a gear mechanism having a complicated shape, or a screw body such as a multi-thread screw for converting rotational motion into linear motion is rolled. The present invention relates to a rolling process method, a processing apparatus, and a molded body of a screw body for processing by the above.

The screw (screw) is introduced in detail in the description of Non-Patent Document 1). Some of them are quoted below.

The screw is provided with a screw-like groove along a cylinder or a conical surface, and is used for fastening a separate member, converting rotational motion and linear motion, or the like. A groove provided on the inner surface of a cylinder or cone is called a female screw, and a groove provided on the outer surface is called a male screw. These are used in combination with each other.

  Today, screws are used in large quantities in every application, many of which are fastening applications with bolts, nuts, wood screws, and the like. Screws are indispensable for the movement and positioning of various machines.

  The processing method of the thread portion can be roughly divided into a rolling method and a cutting / grinding method.

The rolling method is a kind of sequential forming (incremental forming) belonging to plastic working, and is formed gradually and sequentially by pressing a material against a hard mold while rotating the material. The rolling method is suitable for mass production because the processing time is relatively short.

In the rolling process, the thread portion is formed by raising the mountain as much as the valley is pushed by plastic deformation. For this reason, waste materials such as cutting scraps are not produced by rolling.

Machine tools that perform rolling are called rolling machines (some are rolling machines). There are flat die type rolling machines, round die type rolling machines, and planetary type rolling machines. In the case of a male thread, a blank, which is an intermediate product, is strongly sandwiched with a die engraved with a thread, and rotated between them to form a thread. Generally, thread rolling refers to the rolling process of this male thread.

In mass production processing by bolt forging, an intermediate product called a blank having a thick outer shape is made from a wire by a bolt former, and a thread is formed by rolling with a flat die, a round die, a fan die, or the like.

Worm is described in detail in Non-Patent Document 2). Some of them are quoted below. A combination of a screw gear (worm) and a helical gear (worm wheel) matched therewith, a large reduction ratio can be obtained in one stage. Compared with other gear mechanisms, backlash can be reduced.

Generally, the worm wheel is rotated by the rotation of the worm. It is used for music box governors, car steering, astronomical telescope equator, and model train drive.

  Patent Document 1) discloses a worm gear obtained by processing a worm gear (consent with the worm) used for driving a steering wheel of an automobile by a rolling method using a rolling die. Some of them are quoted below.

2. Description of the Related Art As an electric power steering device for a vehicle, there is known a type that decelerates the rotational output of an electric motor through a worm gear mechanism and assists driving an output shaft connected to a steering wheel.

In a power steering apparatus for a light vehicle that does not require a large load, a type in which a metallic cylindrical worm gear and a resin worm wheel are combined to be used as a worm gear mechanism is known.

Since this metal worm gear is required to have high accuracy, the hardened steel is manufactured by lathing and then heat-treating and grinding. When machining with a lathe, it is cut with a cutting tool. To increase productivity, a conical milling machine is used, and the axis of this milling machine is tilted by the advance angle of the pitch line of the worm gear with respect to the worm axis. Cut in the same way.

However, the worm gear manufacturing process requires at least three processes, at least cutting, heat treatment, and grinding. In addition, for this, at least three units of a lathe, a heat treatment facility, and a grinding machine are required. For this reason, the processing cost increased, and the advantages of the worm wheel made of resin could not be fully exhibited.

Further, when rolling a male screw, a worm gear or the like, the first rolling die and the second rolling die which are arranged to face each other approach each other and perform push-feed. At this time, when the advance angle of the worm gear is large and the difference between the finished diameter and the material diameter is large, a phenomenon in which the advance angle changes during the rolling process is called a step.

When this step occurs, the contact of the round die differs between the flank surface of the thread in the moving direction of the workpiece and the opposite flank surface, resulting in a problem that the finished accuracy of the rolled surface is deteriorated. In order to prevent this step, correction may be made by changing the phase position of the first rolling die or the second rolling die in the axial direction, usually by visual observation or the like.

However, in the case of parts that have a male screw or a female screw on either side of the worm gear or a shaft larger than the diameter of the worm gear, the rolling die interferes with this part. Have difficulty.

In such a case, rolling is performed by rotating the die forwardly or reversely. However, due to the occurrence of backlash or the like, a product with high product accuracy cannot be obtained, and the productivity is poor. In Patent Document 2), a spindle tilting mechanism has been proposed in which this step is rotated around an axis perpendicular to the rotation axis of the first rolling die and the second rolling die.

However, even if this spindle tilt mechanism is used, it is not possible to completely prevent the occurrence of steps in workpieces such as worm gears that have a large change in diameter from the start of machining to the end of machining. Appear.

Patent Document 1) Japanese Patent Publication No. 2006-342971: “Worm Gear”
Patent Document 2) Japanese Patent Laid-Open No. 11-285766: “Round Die Type Rolling Device”
Patent Document 3) Patent Publication WO2003 / 000442: “Worm Gear Rolling Method and Worm Gear”
Patent Document 4) Japanese Patent Publication No. 2003-340542: "Warm rolling material"
Patent Document 5) Patent WO2004 / 110669 Publication: “Problem of Rolling Pressure Adjusting Cam”
Patent Document 6) Japanese Patent Publication No. 2007-290001: "Warm flat die rolling machine"
Patent Document 7) Japanese Patent Publication No. 2004-174504: “Rolling Processing Device”
Patent Document 8) Patent Publication No. 2006-224159: “Flat Die for Worm Shaft”
Non-Patent Document 1) http://en.wikipedia.org/wiki/Screw Non-Patent Document 2) http://en.wikipedia.org/wiki/Gear Non-Patent Document 3) Proceedings of the Japan Society of Mechanical Engineers (Part 3) 43) 368, p. 1462 Non-patent document 4) Plasticity and machining 47, 541, p. 100: “Development of multi-axis controlled high-precision machining rolling machine and discovery of new machined products”
Non-patent document 5) Plasticity and processing 47: 541, page 105: “Fine element analysis of screw processing by high precision rolling machine”

  In a rolling process of a screw body having a relatively large module such as a worm, a relatively large random walk occurs and the product is likely to be out of specification. In order to manufacture a worm for a power steering device for automobiles, it is necessary to reduce the random walk to about 10 μm.

  Non-Patent Document 3) disclosed a cause of random walk as a screw pitch error in highly accurate lathe thread grinding. According to this, the factors of random walk were mainly decomposed into mechanical factors, factors due to grinding conditions, and about 10 factors in total. Therefore, in general, it is difficult to identify the factors that have the greatest influence on the random walk in the manufacturing process of the screw product because the effects of many factors must be separated.

As an example of separating the influence factors of random walk, the maximum error was reported as 2.9 μm in the measurement of the precision table turning error of Non-Patent Document 3). From this result, even if a precise machining lathe is used, an error of about 3 μm is mixed, so if the error is about 3 μm, it is considered that the machining is sufficiently precise.

Patent Document 3) discloses a control system for CNC rolling machine of Patent Document 2). FIG. 1 is an external view of the apparatus, and FIG. 2 is an explanatory view of the control system. Mainly, the drive mechanism for changing the rotational speed of the die, the inclination angle of the die spindle, the pushing position of the die, and the position of the workpiece are individually shown. Control.

  This control system is basically a control that applies a classical control theory with one input and one output, and ignores the interaction between control variables. Therefore, when there is a strong interdependency between control variables such as deformation during worm screw rolling, optimal control may be difficult.

  FIG. 3 is an explanatory view showing the state of workpiece rolling by the round die rolling apparatus, in which the upper right is a plan view, the lower right is a front view, and the left is a side view of the workpiece feed base. As shown in the plan view, the workpiece is freely rotated by pressing a recess provided at the center axis position of the end faces of both ends with a support projection fixed to the workpiece feed base. And the unevenness | corrugation of the groove | channel on the surface of a die | dye is gradually transcribe | transferred, being pinched | interposed with the equal pressing force by the round die from the both sides of a workpiece | work, and being pinched by rotation.

  When a load is applied from the die in the axial direction of the workpiece, the workpiece feed base slides in the axial direction. Like a worm, the advance angle changes slightly by pushing, and a movement called “stepping” occurs in the axial direction. In this case, in order to prevent the massive portion at the end of the shaft and the side surface of the die from coming into contact with each other and damaging, the rotation is stopped immediately before the contact and the direction of rotation of the die is reversed.

  FIG. 4 shows the positional relationship per cycle of the opening / closing of the die and the workpiece feed base. In order, (1) mounting, (2) workpiece feeding, (3) rolling: forward rotation, (4) rolling: reverse rotation, (5) opening, (6) taking out is one cycle. However, (3) Rolling: Forward rotation and (4) Rolling: Reverse rotation are alternately performed a plurality of times to adjust the indentation amount of the die and perform desired molding. This is called reciprocating rolling.

Reciprocating rolling is suitable for machining hollow workpieces that are easily deformed by making the angles of the left and right peaks uniform, improving surface roughness, and repeatedly machining with small torque.

  Non-Patent Document 4) investigates the performance of the CNC rolling machine disclosed in Patent Document 2), and the rotation error of the opposing round dies is as small as about 0.01 ° (deg.), And the effective screw The deviation of the thread of the part 1500 mm is as high as about 7 μm in amplitude and is highly effective in reducing the random walk of the screw body. When the module is relatively small, but a screw, a screw with a small random walk that was thinned by grinding with a precision lathe was formed.

  Therefore, a high-precision CNC rolling machine for high-value-added parts that has been difficult to achieve with conventional rolling technology, such as when the module is relatively large and has a small number of teeth, such as a worm of an automotive power steering. The rolling process was developed by

Patent Document 1) discloses a worm rolling condition by a CNC rolling machine. The rotational speed of each rolling die was 10 to 40 revolutions per minute, and the number of forward and reverse rotations was 15 to 50. In addition, as a dwell process, in a state where the pressing operation in which the respective rolling dies approach each other is stopped, the rolling is performed 2 to 5 times per set by the number of forward rotation and reverse rotation. In the dwell process, two to three sets were inserted intermittently at the stage of pushing (cutting operation).

FIG. 5 is an explanatory view showing a mechanism of three-dimensional (3d) deformation of the workpiece. Assuming that the diameter of the die is about 4 times the diameter of the workpiece, the rotation speed of the material is 40 to 160 rotations per minute, and the number of forward and reverse rotations is 15 to 50. It was observed that the portion where the tooth portion (agreement with the thread) was transferred before and after the processing was stretched by about 37% in the axial direction.

From the fact that seven tooth parts (threads) are formed in the axial direction, it can be seen that the extension corresponds to about 2.6 tooth parts. In stretching with the tooth part of the workpiece constrained in the longitudinal direction in the die groove, a maximum of 2.6 rotations of the central axis occur, and the end of the work rotates like a screw screw in the die groove. While stretching is expected.

Thus, in worm rolling, the diameter of the portion where plastic deformation occurs due to contact with the die is reduced, and not only two deformation modes filling the die groove but also extending in the axial direction from the constant volume rule occur. Torsional deformation mode occurs. Accordingly, it has been found that it is necessary to comprehensively control the complicated three-dimensional deformation of the workpiece in order to obtain a desired shape.

  FIG. 6 is an explanatory diagram showing an error due to flat (flat) deformation from a perfect circle of the pitch cylindrical diameter or outer diameter of the double and triple threads. The flat deformation of the workpiece tends to occur when the module is large and the number of teeth is small, such as a worm of an automobile power steering.

  FIG. 7 is an explanatory diagram of a mechanism for generating flat workpiece deformation, and the left diagram is a flowchart thereof. This consists of (1) uneven contact of incomplete thread, (2) spring model of die pressing force, (3) circumferential period variation of effective rolling pressure, and (4) flat deformation of workpiece. This will be described in turn below.

(1) Contact unevenness of incomplete thread part: As shown in the left figure of the first stage in FIG. 7, the incomplete thread part is formed at both ends of the worm. The number and shape of cross-sectional threads passing through the axis change in the circumferential direction of the workpiece. The case where only a complete thread portion with a small number of screw threads (upper right diagram) and the case of an incomplete thread portion with a large number of screw threads (lower diagram in the right diagram) are alternately formed in the circumferential direction. For this reason, non-uniform contact occurs when only the complete thread portion is included and when the incomplete thread portion is included. When adding the same processing amount, in the latter case, the material of the incomplete thread portion escapes into the thread groove, and therefore, the load tends to be lower than in the former case where there is no escape space.

(2) Die pressing force spring model: As shown in the left figure of the second stage in FIG. 7, when rolling a worm with a round die type rolling machine, a pair of dies are pushed in while holding the workpiece from both sides. As a result, the die and workpiece are rotated while the forming load is applied. The mechanism that generates the forming load is because the structural parts of the rolling machine that supports the die are elastically deformed by being pushed by the drive mechanism. This is considered to be equivalent to a model in which a die is supported by a spring compressed by pushing as shown in the right figure. The spring has a monotonically changing relationship between the compression amount and the support load, and can generally be well approximated by a linear relationship. Since the amount of compression of the spring is larger than the amount of deformation of the workpiece per rotation, the pressing force of the die acting on the workpiece is considered to be substantially constant per rotation.

  (3) Circumferential period fluctuation of effective rolling pressure: When the number of axial threads is as small as several, like the worm shown in the first stage of FIGS. 5 and 7, the pressing force of the same die Under the action, the amount of deformation per rotation of the cross section passing through the central axis of the workpiece changes greatly depending on the presence or absence of incomplete thread portions. In a cross section having an incomplete thread portion, the load that can be supported by the incomplete thread portion is reduced, so that the pressing force of the die distributed to the complete thread portion is increased. Therefore, the effective rolling pressure acting on the complete thread portion tends to be larger in the cross section where the incomplete thread portion is present than in the cross section where it is not present. Therefore, the effective forming pressure acting on the complete thread portion periodically varies as shown in the third stage of FIG. 7 with respect to the rotation of the workpiece.

(4) Flat deformation of the workpiece: The amount of deformation of the workpiece per rotation fluctuates periodically with the periodic fluctuation of the effective forming pressure acting on the complete thread portion. Therefore, the pitch cylindrical diameter of the screw thread and the outer diameter of the screw thread tend to cause flat deformation with respect to the target perfect circle. In the case of a double thread, the load fluctuation occurs every half rotation of the workpiece, so that it deforms flattened into an elliptical shape, whereas in the case of a triple thread, it occurs almost every third rotation of the work. Flatly deforms into a triangular shape.

In general, in plastic working, the amount of spring shrinkage and the amount of deformation of the workpiece that are compressed under dynamically balanced conditions are determined, so the cross-section including the incomplete thread that deforms at low loads is compared to the cross section of the complete thread only. The amount of spring shrinkage is large. Therefore, since the pressing force of the die periodically varies by the difference in the amount of spring shrinkage, the circumferential position of the incomplete screw portion can be grasped by measuring this variation.

Regarding flat deformation, when the dwell process is not inserted under the rolling conditions disclosed in Patent Document 1), an oval shape is observed with the double thread and a substantially triangular shape is observed with the triple thread, and the degree is 0. It was disclosed that it is within 0.02 mm in the case of 2 to 0.3 mm and a dwell process. That is, it has been found that the flat deformation is reduced to about one tenth by inserting the dwell process.

  However, in the dwell process, after the workpiece is once flattened by pressing the die, the pressing force is reduced to process. Accordingly, in the dwell process, since the workpiece is processed without substantially pushing (cutting) the workpiece, a productivity reduction of about 30% is inevitable.

FIG. 8 is an explanatory diagram showing a non-uniform shape change when a specific portion of the wire is bent and bent back with a finger. The first bent portion is bent and the portion is work-hardened. Next, when the work-hardened place is bent back to the center, the work-hardened part adjacent to the folded part is broken. This is because of the non-linearity of plastic working. In general, in the plastic working, the final workpiece shape changes depending on the processing history.

Since the dwell allows different machining histories in the circumferential direction of the workpiece, as shown in FIG. 8, a machining history, such as a hardness distribution according to plastic strain, remains in the circumferential direction. As shown in FIG. 6, the workpiece shape after machining is assumed to have a pitch cylinder or outer diameter approaching a perfect circle with respect to the workpiece shape before dwell, but excessive strain in the dwell process is introduced for ideal deformation. Therefore, a negative influence (disturbance) tends to occur on the three-dimensional overall shape of the rolled body.

As shown in FIG. 5, the workpiece is formed into a predetermined product shape by axial stretching accompanied by torsional deformation. Twist occurs selectively in the vicinity of a cross section where the torsional resistance is small. Therefore, if excessive strain introduced in the dwell process is concentrated, non-uniformity occurs in the axial extension of the workpiece. That is, excessive strain in the dwell process, such as bending and unbending of the wire, is a factor in generating a random walk because it tends to induce three-dimensional uneven deformation of the workpiece.

From the above considerations, the dwell process should be abolished as much as possible from the viewpoint of improving productivity and preventing random walks. To that end, it is important to develop a dwell alternative technology that prevents flat deformation of the workpiece.

In Patent Document 4), as shown in FIG. 9, the fluctuation of periodic die pressing force is reduced by processing a notch in advance in a circumferential specific position of a tapered portion at both ends of a processing part for forming a thread. An alternative dwell technique has been disclosed. The notch is a factor affecting the fluctuation of the die pressing force. If the notch can be optimized, an improvement effect may be expected.

However, it is necessary to control the relative positions of the initial cutting and the notch of the workpiece, and it is generally difficult to match the tracking of the complete thread portion and the cutting position. In addition, the effect is limited because the notch portion itself is deformed through roughing and finishing. Furthermore, there has been a problem that four notches have to be formed at the time of material processing, resulting in an additional process.

As a dwell alternative technique, Patent Document 5) discloses a technique of applying a rolling pressure adjusting cam. As shown in FIG. 10, the fluctuation of the periodic die pressing force in the circumferential direction is reduced by adjusting the rolling pressure by supporting the workpiece end portion with a cam during finishing processing at the end of rolling. At the time of finishing processing in which the cam at the workpiece end and the disk at the die end start to contact, an effect of reducing substantial rolling pressure fluctuation and correcting flat deformation is expected.

However, with the countermeasure using the rolling pressure adjusting cam shown in FIG. 10, a pressing force can be applied between the workpiece and the die only at the time of finishing when the cam and the disk on the die side end contact. The finishing process accounts for a small percentage of the entire processing history. for that reason,
It is difficult to correct non-uniform deformation such as flat deformation developed during rough machining only by finishing. Therefore, it is necessary to apply a dwell in order to prevent non-uniform deformation during rough machining, and there is a problem that it cannot be a complete dwell replacement technique.

In order to solve this problem, a mechanism capable of controlling the load at the pressing position of an arbitrary die from the rough machining stage at the start of workpiece machining to the finishing machining stage at the end of workpiece machining is necessary. In addition, many types of small-lot production is carried out by screw rolling. Not only is it difficult to optimize the cam for each product, but it is also necessary to manage and remove the cam for each product. There was a problem to block.

FIG. 11 is an explanatory diagram regarding the workpiece flatness and the inclination of the workpiece central axis. As shown in FIG. 6, since the workpiece undergoes complicated three-dimensional deformation in the thread rolling process, both end portions of the workpiece are extended in the axial direction while rotating the die groove like a screw screw. In FIG. 11, the die and the workpiece are processed while rotating while the workpiece is held between the pair of dies in the vertical direction.

The first row in FIG. 11 schematically shows the circumferential position of the incomplete threaded portion with ◯ and □ marks when the workpiece is a single thread. Since both ends are twisted and stretched while the work is rotating, the marks ◯ and □ move relatively in the circumferential direction along with the order of 1 to 5 indicating the progress of processing.

Both ends of a screw having a large module such as a worm are likely to be flattened due to non-uniform contact between the die and the workpiece as discussed in FIG. The incomplete threaded part marked with ○ and □ markedly deforms because the material escapes into the thread groove. In the case of a single thread, the center axis position of the workpiece moves to the thread groove side. Therefore, as shown in the second stage of FIG. 11, when a straight line connecting the center axis positions at both ends of the screw being deformed is projected onto a plane substantially including the center axis of the workpiece and the die, the order from 1 to 5 The tilt angle changes.

From this, in the case of a single thread screw, the center axis of the workpiece is likely to be touched due to the flat deformation of the workpiece, and the amount of touch is maximum when No. 1 and No. 5 are opposed to the ○ mark and the □ mark, Changes periodically as the workpiece twists. In addition, the amount of contact around the central axis is assumed to change linearly in the axial direction of the workpiece, and since the contact around the central axis is related to the flat deformation of the workpiece, the flat deformation is the largest at both ends of the screw. A decreasing trend is predicted.

Therefore, when the axial length of the tooth portion is short like a worm, the flat deformation amount of the work per rotation is distributed almost linearly in the central axis direction, and the flat area is slightly in the circumferential direction for each rotation. Move one by one. Therefore, axial stretching and torsional deformation around the central axis are also distributed in the axial direction. That is, since the machining history introduced into the workpiece changes locally, non-uniform deformation of the workpiece of several tens of μm easily occurs in the groove of the die machined with high accuracy in units of μm.

In order to manufacture a highly accurate screw body like a worm for power steering in a rolling process, it is necessary to maintain the posture of the workpiece in an appropriate state even under the condition of non-uniform contact between the workpiece and the die. However, as already discussed in the dwell alternative technique, the conventional technique does not disclose a rolling technique for controlling the center axis of a workpiece to a target position at an arbitrary die pushing position. For this reason, there is a problem that the random walk cannot be prevented.

  However, even with a CNC rolling machine capable of high-precision machining of screws, it was difficult to completely eliminate the dwell process in the case of a complicated shape such as a worm. For this reason, accumulation of excess strain inside the workpiece and inhomogeneity of the material are inevitable, and in rolling processing that causes complicated three-dimensional deformation, the basic thread groove such as random walks is affected by non-uniformity such as material hardness. It was a situation where the processing accuracy could not be secured sufficiently.

  Using the same rolling machine, it is possible to ensure the accuracy of the dimension and shape with a long screw, but it is difficult to ensure the accuracy with a worm. The occurrence of random walks becomes a problem in relation to the pitch of the screw thread, but the mechanism by which the pitch fluctuates even when transferred using a high-precision die has been unknown.

  In addition, when rolling with a tool having a predetermined pitch such as a die, all the screw threads are processed at the same time, so it is difficult to create a dimensional shape for each screw thread. When a workpiece causes complicated three-dimensional deformation such as a worm, the basic policy of how to deform the workpiece and make all the threads into a desired dimensional shape has been unknown. For this reason, once the problem of off-size occurs, there is a risk that it will fall drastically to solve it.

  The thread groove of the die that transfers the worm thread is finished in the grinding process. Attempts have been made to improve thread workability and thread rollability by making the cross-sectional shape of the thread groove into a shape that connects arcs or straight lines. Patent Document 1) discloses a screw-shaped worm that is compatible with a CNC rolling machine.

The screw shape disclosed in Patent Document 1) uses a circular arc to pattern the design and input of the grinding machine, and is effective for labor saving, while being plasticized along the shape of the screw groove of the die during rolling. This has been an obstacle in optimizing thread forming to limit the flow of flowing material.

  For example, even if it is defined as a shape that connects arcs or straight lines in a cross section perpendicular to the spiral screw groove or a cross section passing through the central axis of the screw, plastic flow along the shape of the screw groove of the die during the rolling process Naturally, the direction of the flow of the material is in the middle of both cross sections. The optimization of the screw shape that realizes the material flow suitable for the plasticity theory has been an issue.

  The inventor has realized that a person skilled in the art assumes a uniform deformation with an implicit understanding as a three-dimensional deformation state of an ideal work that is unlikely to cause random walks. It is natural to expect that the screw shape of the die is transferred to the workpiece at uniform intervals if the workpiece is uniformly deformed.

However, the minimum non-uniform strain necessary for transferring the screw shape is generated. In general machining, excessive strain is generated in addition to the minimum strain, and uniform deformation of the workpiece is impaired. Therefore, the ideal workpiece deformation was considered to be the deformation with the least excess strain. In general, it has been difficult to find a deformation path that minimizes the excess strain by trial and error using an actual machine test, which causes an increase in cost.

Therefore, using plastic working theory, we grasp the conditions that the whole workpiece approaches an ideal uniform deformation state, and based on that knowledge, flexible rolling machine with necessary hardware and flexible with necessary intelligence (intelligence). I envisioned a next-generation intelligent rolling machine consisting of a control system, and solved the problems as shown below through its development.

That is, according to the first aspect of the present invention, the pushing force and / or the pulling force is applied between any of the workpiece and the die, the die mounting base, and the structural member supporting the die in synchronization with the rotation of the workpiece at an arbitrary die pushing position. This is a rolling process method for a rolled body, characterized in that, by applying a load, the relative position between the work and the die is maintained in a target state, and the work is rolled by the die.

In the second invention, the die is a round die or a flat die, and the workpiece is pressed between any one of the workpiece and the die, the die mounting base, and the structural member that supports the die at the pushing position of the arbitrary die. A screw body rolling method comprising applying a pressing force and / or a pulling force to maintain a relative position of a workpiece and a die in a target state and rolling the workpiece with a die.

The third aspect of the present invention supports a pressing force and / or between a workpiece and a die, a die mounting base, and a structural member supporting the die while supporting the rotation around the center axis of the workpiece and the movement in the direction of the center axis. Or it is a rolling process method of the screw body characterized by applying a pulling force.

According to a fourth aspect of the present invention, there is provided a method of rolling a threaded body, wherein the circumferential position of the incomplete thread portion of the workpiece is tracked by detecting a rotation pulse of the workpiece and / or detecting a load variation and synchronized with the rotation of the workpiece. It is.

According to a fifth aspect of the present invention, there is provided a thread rolling process characterized in that the workpiece is rolled while being loaded with an axial force and / or a torsion torque around the axis, and a bending moment of the workpiece center axis is loaded as desired. Is the method.

According to a sixth aspect of the present invention, there is provided a method of rolling a threaded body, wherein forced lubrication by a workpiece coolant and / or vibration by a vibration device is applied.

In the seventh aspect of the invention, a pressing force and / or a pulling force is applied between the workpiece and the die, the die mounting base, or the structural member supporting the die in synchronization with the rotation of the workpiece at an arbitrary die pushing position. It is a rolling processing apparatus of a rolling body characterized by having a drive mechanism.

In an eighth aspect of the invention, the die is a round die or a flat die, and the workpiece is positioned between any one of the workpiece and the die, the die mounting base, and the structural member that supports the die in synchronism with the rotation of the workpiece at an arbitrary die pushing position. A screw body rolling apparatus having a drive mechanism for applying a pushing force and / or a pulling force.

According to a ninth aspect of the present invention, there is provided a thread rolling apparatus characterized by having a support mechanism at both ends of the workpiece for supporting the rotation around the center axis of the workpiece and the movement in the direction of the center axis.

A tenth aspect of the invention is a thread rolling apparatus having a workpiece rotation pulse detection mechanism and / or a load fluctuation detection mechanism for detecting an incomplete thread portion of a workpiece.

An eleventh invention is characterized by having a drive mechanism for loading an axial force and / or torsional torque about the axis on the workpiece and, if desired, a bending moment of the workpiece central axis, if desired. It is.

A twelfth aspect of the present invention is a thread rolling apparatus having a forced lubrication mechanism using a workpiece coolant and / or a vibration mechanism for vibrating the workpiece.

In the thirteenth aspect, the measurement data includes a flat load, a gap between the die and the workpiece, back pressure at both ends of the workpiece, torque at both ends of the workpiece,
Including one or more of the rotational position and workpiece length at both ends of the workpiece, the workpiece gripping part is pushed and pulled as the drive mechanism command, the workpiece end is pushed in the axial direction, and the workpiece end is twisted around the axis It is a thread rolling apparatus characterized by having a control system including one or more of the following.

A fourteenth aspect of the invention is a thread rolling apparatus characterized in that the control system is a multivariable control system and has a control model and / or a learning control function.

A fifteenth aspect of the present invention is a molded body of a rolled body, characterized by being manufactured by the rolling processing method according to claim 1 and / or the rolling processing apparatus according to claim 7.

A sixteenth aspect of the present invention is a molded body of a screw body manufactured by the rolling processing method according to any one of claims 2 to 6 and / or the rolling processing apparatus according to any one of claims 8 to 14. It is.

The seventeenth invention is characterized in that the shape of the bottom of the tooth between the workpiece teeth is expressed by a piecewise continuous curve having a monotonic function having no inflection point, and the tooth thickness is smaller than the interval between the bottoms of the tooth if desired. It is a molded body of a screw body.

  In the following, description will be made using examples in which the effect of the invention is considered to be remarkable, as necessary. The lower part of FIG. 5 is a worm component disclosed in Non-Patent Document 4). The material is S45C, the outer diameter is 18 mm, the length is 86 mm, the neck diameter is 9.8 mm, the tooth part length is 35 mm, and the number of screws is two. In the embodiment, a worm component is formed by rolling from the upper material of FIG. This part was manufactured by cutting, heat treatment and grinding because of the strict accuracy of dimensions and shape. Since this is manufactured by a rolling process, the overall dimensional accuracy of the teeth, especially the occurrence of screw random walks, is reduced. In addition, in order to easily understand the principle and the like, when the conditions are different, such as when the number of screw threads is 1, this is clearly indicated in the corresponding part.

The effect of the rolling method of the rolled body according to the first invention will be described.

  FIG. 12 is an explanatory view showing the structure of the flat deformation preventing device for the workpiece 12 installed on the die mounting base 10 of the round die type rolling machine. 12 (a) and 12 (d) are a plan view and a front view before installation of the flat deformation prevention device, and FIGS. 12 (b) and 12 (e) are a plan view and a front view after installation of the flat deformation prevention device. (C), (f) of FIG. 12 is the top view and front view of the installed flat deformation prevention apparatus. In the embodiment, the round die type rolling machine uses the rolling machine shown in FIGS. 1 to 4 disclosed in Patent Document 2), but a general rolling machine may be used.

As shown in FIGS. 12 (a) and 12 (d), a pair of opposing die moving tables 16 are placed on a beam shaft 17 installed on a gantry (not shown) so as to move in a direction along the beam shaft 17 by a drive mechanism (not shown). It is movably attached to enlarge or reduce the gap. A die mounting table 10 that rotatably supports the round die 11 is mounted on the die moving table 16 so as to be tiltable within the mounting surface of the die moving table 16.

A groove for forming a screw thread is machined on the outer periphery of the round die 11. After holding the workpiece 12 with a pair of round dies 11 and pushing it in with the die moving table 16, each round die is synchronized. The screw is rolled by plastic working while rotating the workpiece 12 while rotating in the same direction. When the pushing amount increases, the die mounting base 10 is tilted to prevent the workpiece 12 from stepping in the axial direction. For a more detailed mechanism, see Patent Document 2).

The thin gradation lines in FIGS. 12B and 12E show the structure of the rolling machine in FIGS. 12A and 12D, and the dark gradation lines indicate the main parts of the installed flat deformation prevention device. Indicates. In other words, the main part of the workpiece flat deformation prevention device includes a drive mechanism 13, a workpiece end support mechanism 14, and a gripping tool 15. The driving mechanism 13 is embedded in a die mounting base, and gripping tools 15 that transmit a pressing force or a pulling force are installed on both sides of the die 11 at the tip of the moving shaft of the driving mechanism 13. Usually, since two gripping tools are required for each die, the rolling machine of FIG. 12 has two dies, so that the embodiment includes a total of four gripping tools.

The thin gradation lines in (c) and (f) of FIG. 12 show the workpieces and dice of (a) and (d) in FIG. 12, and the dark gradation lines indicate the main part of the installed flat deformation prevention device. Show. The moving shaft of the drive mechanism of the flattening prevention device moves in the direction of the arrow to transmit a pressing force to the gripping tool, and the gripping tool grips the workpiece end support mechanism or the workpiece and transmits the pressing force to the workpiece. In addition, the movement axis of the drive mechanism of the flat deformation prevention device moves in the direction opposite to the arrow to transmit the pulling force to the gripping tool, and the gripping tool grips the workpiece end support mechanism or the workpiece and pulls on the workpiece. To communicate.

The gripping tool includes one drive mechanism. However, in the case of FIG. 12, the gripping tool is provided with two drive mechanisms 13 on both sides of the bearing box in order to avoid interference between the drive box and the bearing box that freely supports the die shaft. Although FIG. 12 shows an example in which a hydraulic cylinder is used as the drive mechanism 13, an electric drive mechanism such as a servo motor can also be used.

In the case of FIG. 12, it is also possible to divide the gripping tool into two parts or a plurality of parts. At that time, the mounting position can be made closer to the die by downsizing and dispersing the drive mechanism.

From the processing conditions disclosed in Patent Document 1), the rotation speed of the workpiece is about 40 to 160 rotations per minute, that is, about 0.7 to 2.7 rotations per second, and the load of the driving mechanism is 1.6 tons at most. Therefore, a conventional driving mechanism can be used.

Although not shown, a load meter for measuring a load acting on the tool and a displacement meter for measuring the position of the tool are installed. The load cell is preferably a load cell, and the displacement meter is preferably a compact device such as a linear gauge.

The gripping tool 15 holds the support mechanism 14 at the end or both ends of the work 12 from each die mounting base 10 by the drive mechanism 13. In general, the gripping tool 15 applies a pressing force to the end portion of the work 12, but if desired, a support mechanism 14 at both ends of the work and a gripping mechanism for fixing the gripping tool 15 are provided to support the support mechanism 14. It is also possible to apply a pulling force to both ends of the work 12 via

In addition, since a step occurs in the axial direction when rolling a large screw of a module such as a worm, in the rolling machine disclosed in Patent Document 1), a step control is performed in which a die mounting base is tilted to adjust an apparent screw advance angle. Is implemented. In this case, since the workpiece flat deformation preventing device is also tilted together with the die mounting base, the positional relationship between the workpiece, the drive mechanism, and the gripping tool changes with the tilt. In this case, in order to transmit the pushing force or pulling force of the drive mechanism to the work via the gripping tool, a mechanism that absorbs the relative position change of the work, the drive mechanism, and the gripping tool may be installed.

Since the tip of the moving shaft of the drive mechanism slides on the surface of the gripping tool, even if the relative position of the gripping tool changes, the tip of the moving shaft comes into contact with ease, so that it is possible to transmit a pressing force. Further, it is possible to transmit a pulling force by processing a rail or a groove on the sliding line and providing a mechanism in which the tip of the moving shaft of the drive mechanism embraces the rail or a mechanism that fits into the groove.

FIG. 14 is an explanatory view showing the operating principle of the flat deformation preventing device for a workpiece in the case of a single thread. The flat deformation of the work is caused by the circumferential fluctuation of the effective rolling pressure shown in FIG. Therefore, in order to cancel this periodic variation, a periodic variation load may be applied between the end portion of the workpiece and the die or the die mounting base.

Further, as shown in the second stage of FIG. 7, the pressing force applied to the workpiece from the die is supplied by the elastic strain of the die, the die mounting base, and the structural member that supports the die when the die is tightened. The In the embodiment of FIG. 12, the drive mechanism of the workpiece flattening prevention device is installed on the die mounting base. However, if it is installed on at least one of the die, the die mounting base, and the structural member that supports the die, the desired effect can be obtained. Can demonstrate.

In that case, the stroke of the drive mechanism of the workpiece flat deformation prevention device can be reduced by installing it as close to the die as possible. Therefore, it is preferable to install the die, the die mounting base, and the structural member that supports the die in this order. In FIG. 12, the drive mechanism is divided to prevent the interference between the drive mechanism of the workpiece flattening prevention device and the bearing that supports the die. However, if desired, the drive mechanism is installed on a structural member that supports the die to cause interference. It is also possible to eliminate the above and make a single drive mechanism.

The upper part of FIG. 14 is a plan view showing the position of the incomplete screw portion in the case of a single screw in the die, the work and the work support mechanism, and the lower part is a die pressing force acting on the work in the work and the work support mechanism. It is a top view which shows the cyclic | annular fluctuation load provided with a flat deformation prevention apparatus with an arrow. The circumferential position of the incomplete thread is increased by an angle of one quarter (90 °) when θ = 0 ° on the left, θ = 90 ° on the center, and θ = 180 ° on the right. ing. When θ = 0 ° and θ = 180 °, the incomplete thread portion is in contact with one die. Further, when θ = 90 °, the incomplete thread portion does not contact any of the dies.

The workpiece is sandwiched by dies from both sides and receives a rolling load. When the incomplete threaded part of the workpiece is in contact with the die at θ = 0 °, the effective rolling pressure is such that both the workpiece end and the shaft portion of the die are separated by a driving mechanism and a gripping tool (not shown). The load which cancels the circumferential direction fluctuation | variation of is loaded. The load applied to the shaft portion of the die is superimposed on the rolling load of the die and reduces the rolling load applied from the die to the workpiece. Accordingly, since the effective rolling pressure of the workpiece is maintained at substantially the same value as that of the complete thread portion, the circumferential period fluctuation of the effective rolling pressure and the flat deformation of the workpiece do not become apparent.

At this time, the work surface in contact with the other die is a complete thread portion, and an appropriate forming load is applied from the die, so that no load is required by the gripping tool. Further, except that the contacting die changes, the same thing as θ = 0 ° holds true when θ = 180 °.

When θ = 90 °, the surface of the workpiece contacting each die is in the middle of transition from the incomplete thread portion to the complete thread portion. Therefore, as shown in the drawing, a slightly smaller load is applied by the gripping tool as compared with the case where the incomplete thread portion of θ = 0 ° or θ = 180 ° is applied. As a result, the effective rolling pressure of the workpiece is maintained at substantially the same value as that of the complete threaded portion, so that the circumferential rolling fluctuation of the effective rolling pressure and the flat deformation of the workpiece hardly occur.

Since the pushing force and / or the pulling force can be applied in synchronization with the rotation of the workpiece, the circumferential period fluctuation of the effective effective rolling pressure (see FIG. 7) while tracking the angle θ of the incomplete thread portion. A load that cancels out the third stage) can be applied to the workpiece.

In FIG. 14, for the sake of simplicity of explanation, it is assumed that the angles of the incomplete screw portions at both ends of the single thread screw are the same, but the same effect can be obtained even if the angles of both are different. Further, even if the number of threads of the screw changes to a plurality, the drive mechanism of the workpiece flattening prevention device may be operated in synchronization with the position of the rotating incomplete screw portion. That is, by controlling the effective rolling pressure to be constant, the relative positions of the center axes of the workpiece and the die can be maintained in the target state.

Specifically, in the lower part of FIG. 11, the center axis of the workpiece is held at the third position substantially parallel to the axis of the die during the rotation of the workpiece. Accordingly, the center axis can be prevented from swinging, so that uniform rolling in the circumferential direction is possible.

Each drive mechanism of the flat deformation preventing device of the workpiece has a stroke necessary and sufficient to absorb the expectation that the distance between the center axis of the die and the center axis of the workpiece gradually decreases due to the pushing of the die. Therefore, by maintaining the relative position of the workpiece and the die at an arbitrary position from the roughing process at the initial stage of rolling to the finishing process at the end of the rolling process, it is possible to form a rolled body close to a perfect circle. .

By applying the rolling method of a rolled body according to the present invention to the processing of a rolled body that has been corrected by inserting a dwell process, flat deformation can be achieved even if the dwell process is completely abolished. Can be prevented.

As a remarkable feature of the rolling process method of the rolled body of the present invention, the shape of the rolled body that deviates from the perfect circle shown in FIG. This controls the distance between the center axis of the workpiece and the center axis of the die and actively uses the periodic fluctuation of the effective rolling pressure. For example, it can be realized by applying an effective rolling pressure so that the locus of the contact portion of the die traces the shape of the desired rolled body.

By applying this rolling method, the cross-sectional shape of the workpiece before rolling is made into a circular shape of a commercially available bar or wire, and the cross-sectional shape of the rolled product after rolling is an ellipse or a substantially polygon with high added value. It becomes possible to mold into.

It is also possible to gradually change the cross-sectional shape in the axial direction of the workpiece. For example, a shape like a twisted wrinkle can be created by rotating the cross-sectional shape according to the position of the shaft. In such a case, it is possible to further expand the modeling range by changing the relative position between the die and the workpiece by changing the shape of the rolling surface of the die to a versatile one.

Further, as a remarkable feature of the rolling process method of the rolled product of the present invention, it can be combined with the prior art. As already described, the drive mechanism of the workpiece flat deformation prevention device can exhibit a desired effect if it is installed on at least one of a die, a die mounting base, and a structural member that supports the die. Therefore, the driving mechanism of the work flattening prevention device can be installed avoiding the rolling pressure adjusting cam and the disk-shaped plate disclosed in Patent Document 5) shown in FIG. Further, a worm rolling material having a notch disclosed in Patent Document 4) can be formed by a rolling machine having a work flattening prevention device. Therefore, by supplementing the process capability deficient in the prior art by the rolling processing method of the rolled body of the first aspect of the present invention, it becomes possible to perform rolling processing of highly accurate dimensions and shapes that are difficult to achieve with the prior art alone. .

Although the above has mainly described the rolling process of a screw body such as a worm whose dimension and shape accuracy is extremely severe, it is obvious that it can be applied to a rolling process of a general molded body having a low dimension and shape accuracy. .

The effect of the thread rolling method of the second invention will be described.

  Patent Document 6) discloses a flat die rolling machine for worms. FIG. 13 (a) is an explanatory view showing the structure of the main part centering on the workpiece and the flat die of the disclosed flat die rolling machine for worm. The column 20 is pivotally supported by the column base 23 constituting the gantry so as to be tiltable within the mating plane. The column 20 has a concave cross section, and a slide base 22 is installed on one side of the column 20 so as to fit into the groove. A flat die 21 is fixed to the other side of the column.

Since the flat die 21 is regarded as a case where the diameter of the round die of FIG. 12 is increased, the structure of FIG. 13A is basically the same as the structure of FIG. That is, a groove for forming a screw thread is formed on the surface of the flat die 21, and the die is passed in the feeding direction by the driving mechanism of the sliding table 22 while the work 12 is held between the pair of flat dies 21. The screw is rolled by plastic working while rotating the workpiece 12. When the pushing amount increases, the column 20 is tilted to prevent the workpiece 12 from stepping in the axial direction. For a more detailed mechanism, see Patent Document 6).

FIG. 13 (b) is an explanatory view showing the appearance of the device when an embedded flat deformation preventing device is attached to the column 20. The thin tone line indicates the structure of the rolling machine of FIG. 13 (a), and the dark tone line indicates the main part of the installed flat deformation prevention device. In other words, the main part of the workpiece flat deformation prevention device includes a drive mechanism 13, a workpiece end support mechanism 14, and a gripping tool 15. The drive mechanism 13 is embedded in the column 20, and gripping tools 15 that transmit a pressing force or a pulling force are installed on both sides of the die 11 at the tip of the moving shaft of the drive mechanism 13. Normally, since two gripping tools are required for each die, the rolling machine of FIG. 13 has two dies, so that the embodiment includes a total of four gripping tools.

The arrangement and structure of the workpiece, the drive mechanism, and the gripping tool are substantially the same except that the die is changed from a round die to a flat die by comparing FIG. 13 and FIG. Therefore, it can be easily understood that the flat deformation prevention mechanism of the workpiece shown in FIG. 14 functions in the same way as in the case of a round die even in the case of a flat die.

  Therefore, the method of rolling a screw body according to the second aspect of the present invention is effective for manufacturing the screw body disclosed in Patent Documents 1) and 6) into a highly accurate dimensional shape.

The effect of the thread rolling method of the third invention will be described.

In the techniques disclosed in Patent Literature 1) and Patent Literature 6), the workpiece is supported by the center of positioning and core pushing so that the depression at the center of both end faces is sandwiched and freely rotated. A method of holding a workpiece using a center that is moved by a pneumatic drive mechanism has been disclosed. In addition to fixing the position of the center axis of the work, the work is supported freely by adjusting the frictional force between the center and the work.

Further, the workpiece feed base is moved according to the workpiece step generated during machining, and the workpiece is supported so as to be movable in the axial direction of the workpiece. In the case of the embodiment, the workpiece is positioned by receiving a machining force of 10 tons or more from both sides by pressing with the die, so that the main positioning direction of the center is the tangential direction of the contact surface of the die.

  In the first and second aspects of the present invention, as shown by an arrow in FIG. 14, a pushing force or a pulling force of about 1.6 tons or less acts on the workpiece being machined from the workpiece flat deformation prevention device. Therefore, when the gripping tool is in direct contact with the workpiece, the gripping tool that transmits the pressing force or pulling force and the frictional force of the workpiece act as disturbances, so that the rotational motion and the axial motion of the workpiece are likely to be disturbed. In that case, in the center of the conventional technique, the relative position between the work and the die may deviate from a predetermined position, and thus the work may be deformed abnormally.

FIG. 15 is an explanatory view of a mechanism for supporting both ends of a work disclosed in the third aspect of the present invention. The lower left figure in FIG. 15 is an explanatory view showing the appearance of the work feed table, and the part surrounded by a round frame is enlarged and shown in the upper part of FIG. 15 showing the structure of the work and its supporting part. .

In the embodiment, similarly to the techniques disclosed in Patent Document 1) and Patent Document 6) already described, the work 12 is held freely at both ends by a pair of centers 30 from both sides. . The workpiece 12 and the center 30 are arranged so that the outer periphery of the workpiece 12 and the center 30 are covered with a substantially cylindrical workpiece end support mechanism 31, and one end of the workpiece end support mechanism 31 is attached to and detached from the outer periphery of the end of the workpiece via a bearing 33. Fit as possible. The other end side of the workpiece end support mechanism 31 is supported in a state in which almost no load is applied by an outer peripheral surface of a cylindrical portion installed coaxially with the center 30 and a flexible support (not shown). Further, the outer peripheral surface of the workpiece end support mechanism 31 is detachably fitted to a gripping tool (not shown) via a linear motion bearing 32.

Therefore, as indicated by arrows in FIG. 14, the pushing force or pulling force from the workpiece flattening prevention device is transmitted to the workpiece via the support mechanisms at both ends of the workpiece that are gripped by a gripping tool (not shown).

The rotation of the workpiece 12 by a die (not shown) is absorbed by the workpiece 12 and the bearing 33 of the workpiece end support mechanism. Further, the movement of the workpiece 12 in the axial direction caused by the step is absorbed by the linear motion bearing 32 of the workpiece end support mechanism. Therefore, the pushing force or pulling force by a gripping tool (not shown) does not disturb the step of the workpiece 12.

According to the rolling processing method of the screw body of the third aspect of the present invention, even when a pushing force or a pulling force is applied to the workpiece by the driving mechanism of the workpiece flat deformation prevention device, the workpiece does not deform abnormally. Products with highly accurate dimensions can be processed.

The effect of the thread rolling method of the fourth invention will be described.

FIG. 16 is an explanatory diagram for tracking an incomplete thread portion of a workpiece being processed. As shown in the upper part of FIG. 16, the circumferential position of the incomplete thread portion of the workpiece changes as the machining progresses. The flat deformation preventing device for a workpiece disclosed in FIGS. 12 and 13 causes the same deformation as that of only the complete screw portion when the incomplete screw portion of the workpiece is rotated to a position in contact with the die as shown in FIG. To control the load. Accordingly, it is necessary to properly operate the flat deformation prevention device of the workpiece in synchronization with the rotation of the workpiece while tracking the circumferential position of the incomplete screw portion every moment.

In general, tracking methods are roughly classified into a method for detecting a rotation pulse of a workpiece and a method for detecting a load fluctuation.

When machining is started by attaching the workpiece to the center and holding it with a die, adjust the position so that the incision position of the die becomes an incomplete screw part, and attach, notch, magnetizing, coloring, sealing, etc. Irregularities such as wrinkles, indentations and the like are provided as marks on the end of the workpiece before processing. This mark is detected by a sensor during machining, and the mark position is traced from the history of the rotation speed of the workpiece. The position of the incomplete thread portion can be predicted with respect to this mark.

However, when applying a theory capable of predicting the position of the incomplete thread portion, the initial cut position may be set to the complete thread portion or another position. Moreover, when using the below-mentioned rotary encoder and a dedicated tracking mechanism, the position of an incomplete thread part can be estimated using this.

The method for detecting the load variation utilizes the property that the rolling indentation reaction force periodically varies between the incomplete screw portion and the complete screw portion. The load fluctuation is recorded with a load meter, and the position of the incomplete screw portion is extracted from the history of the rotation speed of the workpiece. This method can be realized relatively easily by measuring the forming load during the rolling process. Moreover, a synergistic effect can be expected by combining with a method for detecting a rotation pulse of a workpiece.

Since the rolling process is repeated many times by reciprocating rotation such as reciprocating rolling of a round die or reciprocating motion of a flat die, the measurement result of the previous cycle can be stored and the next cycle can be predicted. . Accordingly, the tracking of the circumferential position of the incomplete thread portion can be performed with high accuracy, and thereby the flat deformation of the workpiece can be reliably prevented.

The effect of the rolling processing method of the rolled body which is the fifth invention will be described.

FIG. 17 is an explanatory diagram showing an increase phenomenon of the axial length of a workpiece reconstructed based on the explanatory diagram disclosed in Patent Document 4). The left figure in FIG. 17 shows the relative position between the workpiece and the die before machining, the middle figure in the middle of machining, and the right figure after machining. As the machining progresses, the pressing position of the die approaches the workpiece center axis, so that the material stretches in the axial direction or penetrates into the thread groove and deforms into a screw thread from the constant volume rule.

FIG. 18 is an explanatory diagram showing a torsional deformation state of a screw end portion that simply expresses a deformation simulation result of a work in a screw rolling process by finite element analysis disclosed in Non-Patent Document 5). When rolling a screw of a normal module, the center axis of the workpiece is torsionally deformed with processing, and the torsion angle of the workpiece increases while maintaining a substantially linear relationship with the rotation angle of the round die. Then, it was predicted that the workpiece would twist about a maximum of 45 ° (one-eighth rotation) when the die changed by 180 ° (half circumference).

FIG. 5 is an explanatory diagram estimating the three-dimensional deformation state of the workpiece in the worm rolling process. Since the deformed portion of the work is concentrated on the thread forming portion, the average axial elongation is expected to reach about 37%. Then, the workpiece is stretched in the axial direction while being aligned with the groove on the die surface without breaking the transferred thread at the initial stage of processing. As a deformable state in which this is possible, it was predicted that both ends of the screw would rotate about 2.6 times relatively.

In actual machining, in order to prevent the step, the central axis of the die is inclined to change the apparent advance angle of the screw groove, so that the relative rotational speeds at both ends due to the torsion of the workpiece are different from those predicted. In addition, since the axial deformation center of the threaded portion is different from the axial deformation constraint of the material, the deformation of the weakly constrained end portion is more variable than the deformation of the highly constrained central portion. Easy to be affected. The variation is directly related to the balance fluctuation of the three-dimensional deformation of the workpiece such as axial extension, torsion around the central axis, and bulge of the thread. In order to prevent variation in deformation, it is necessary to reduce variation in deformation constraint in the workpiece axis direction.

FIG. 19 is an explanatory view showing the structure of a push-twist type work feed base disclosed in the fifth aspect of the present invention. The lower part is a work feed base that incorporates a mechanism for forcibly rotating a work in synchronism with the rotation of a die disclosed in Patent Document 7), and the pressing force in the direction of the central axis and the torque around the central axis are applied to the work. It is an external view of the workpiece feed stand incorporating the mechanism to load.

The upper part of FIG. 19 is an enlarged explanatory view of the load mechanism of the workpiece, and the pressing mechanism is substantially the same as the pressing mechanism of the round die disclosed in Patent Document 2). A pair of pushing tables 43 installed on the beam shaft 44 hold the workpiece 12 from both ends. An axial force (back pressure) is applied to the workpiece 12 by the drive mechanism 40 of the workpiece axial force installed on one pushing table 43, and the other pushing table 43 passes through a torque transmission shaft 42 driven by the rotation driving mechanism 41. Then, a torsional torque around the workpiece center axis is applied to the workpiece 12.

That is, since the equal load from both ends of the work acts in the opposite direction to the work stretching, it corresponds to the back pressure in terms of plastic working. This back pressure increases the axial restraining force at both ends of the threaded portion where the axial restraint by the die is weak, so that the axial displacement restraint is equalized and the occurrence of variation in the deformation of the workpiece is suppressed. Therefore, it is considered that the back pressure load is highly effective in reducing variations in the thickness of the thread and the height of the thread.

It is expected that the axial restraint force (back pressure) suppresses this variation in torsional deformation. If the variation in torsional deformation deviates from the allowable limit even when back pressure is applied, torque can be applied in a direction to suppress torsional deformation. This is a method of applying an angular velocity slightly faster than the rotational speed of a workpiece rotating in synchronization with the die rotation by a rotating mechanism forcibly rotating the workpiece in synchronization with the die rotation disclosed in Patent Document 7), This can be realized by combining a method in which a brake is applied to the part to give a rotational speed slightly slower than the rotational speed of the work rotating in synchronization with the die rotation. The push-twist type work feed base shown in FIG. 19 can be applied to both the round die shown in FIG. 12 and the flat die shown in FIG.

By the way, Patent Document 8) discloses a flat die for a worm shaft. When a worm that generates a step is rolled using a normal belt-shaped flat die, a shaft bending defect is likely to occur at the end of the threaded portion. Patent Document 8) explained that the cause is that the end of the threaded portion is processed more than necessary. In any case, if the bending moment of the workpiece central axis acts on the material being plastically deformed, the bending of the shaft easily occurs.

As shown in the lower part of FIG. 14, a load is applied to the end portion of the workpiece by the driving mechanism of the flat deformation prevention device. In this case, since the applied load generates a bending moment of the workpiece central axis at the end of the threaded portion, if the moment is excessive, there is a concern that the bending failure of the workpiece may occur.

In this case, a bending moment in the opposite direction that cancels the bending moment of the workpiece center axis can be applied to the workpiece both-end support mechanism shown in FIG. As a result, the center axis of the workpiece after machining becomes straight, and it becomes possible to manufacture a product with a highly accurate dimensional shape.

The effect of the thread rolling method of the sixth invention will be described.

As shown in FIG. 17, since the workpiece in the middle of processing is not filled in the groove portion for transferring the screw thread of the die, the contact state between the die and the workpiece has variations in the longitudinal direction of the workpiece. In general, the central portion of the workpiece, which has strong deformation constraint in the direction of the workpiece center axis, is filled first to cause strong frictional constraint, whereas the end portion with weak deformation constraint is delayed in filling and the frictional constraint is also weak. Accordingly, it is necessary to make the frictional constraint uniform in order to make the deformation of the entire workpiece uniform.

In general, as a method for making the frictional constraint uniform, there are a forced lubrication method using a workpiece coolant and a method using a vibration device.

The forced lubrication method using coolant for workpieces has been applied to various types of plastic processing and has a proven track record. This is done by applying a lubricant or emulsion to the contact surface of the workpiece or tool. In the case of an emulsion, water having a high cooling capacity is the main component, so that it is also effective for removing work heat of a workpiece or a tool. Therefore, it can be used to control thermal strain.

As a method of applying vibration by a vibration device, a powerful vibration transmitter has been developed and its application to plastic working has been reported. When a vibration is applied to the workpiece or the die and the contact surface between the workpiece and the die is vibrated at a high cycle, a gap is locally generated in a part of the contact surface to generate a minute relative deviation. When the frequency is high, the occurrence frequency of the gap increases, and the location of the relative deviation expands over the entire contact surface, so that the influence of the relative deviation between the workpiece and the die becomes obvious. That is, when the contact state is made uniform, the contact boundary condition changes and the deformation of the workpiece is made uniform. Therefore, it is expected that the random walk and the like are reduced by making the deformation of the workpiece uniform.

The effect of the rolling processing apparatus of the rolled body which is 7th invention is demonstrated.

FIG. 12 is an explanatory view showing an embodiment of the rolling processing apparatus for a rolled body disclosed in the seventh aspect of the present invention. The die mounting base of the round die type rolling machine shown in FIG. A deformation prevention device was installed. In Patent Document 5), as a countermeasure against flat deformation of a workpiece, as shown in FIG. 10, a rolling pressure adjusting cam is provided at both ends of the workpiece, and a rolling pressure adjusting cam and a circumferential surface are in contact with both sides of a die. Was installed. And it was supposed that it was effective in preventing the flat deformation of the workpiece in finishing at the end of rolling, and this was presumed to be because the machining was carried out according to the principle of preventing flat deformation shown in FIG.

In the embodiment, the driving mechanism, the gripping tool, and the support mechanism for the workpiece end are replaced by a rolling pressure adjusting cam and a disk so that the principle of flat deformation prevention shown in FIG. 14 acts from the start to the end of the rolling process. Arranged. The drive mechanism may be installed on any of a die, a die mounting base, and a structural member that supports the die.

In the embodiment, since the maximum capacity of one drive mechanism is set with a margin of about 2 tons, a cylinder cross-sectional area of at least about 100 cm ^{2 is} required when a hydraulic source of 20 kg / cm ² is used. In the embodiment shown in FIG. 12, the drive mechanism is embedded in a die mounting base that can approach the die due to the installation space.

In the embodiment, the both ends of the workpiece, which is the position of the cam in Patent Document 5), are loaded by a driving mechanism via a gripping tool. The work being rolled is held between dies and a forming load of 10 tons or more is applied. Further, the work is constrained to rotate freely from both sides with the center of both end faces at the center, and machining is continued in a macroscopically stable posture even without a flat deformation preventing device for the work. Since the drive mechanism of the flat deformation prevention device of the workpiece acts a load whose direction changes in the direction of the molding load acting from the die to the workpiece, if the friction force with the workpiece is ignored, the macroscopic workpiece posture will not be disturbed Absent.

In general, since the bending deflection of the die in the axial direction of the workpiece can be ignored, maintaining the relative position such as the inclination and distance between the contact surface of the die and the central axis of the workpiece shown in FIG. Is important to. The posture control of the workpiece is performed according to the operation principle of the flat deformation prevention device shown in FIG.

That is, since the posture control of the workpiece is control of the load acting on the workpiece, it is necessary to measure the load acting on the workpiece. A load meter (not shown) is installed to measure the pressing force of the die and the pressing force or pulling force of each drive mechanism of the flat deformation prevention device.

Since the rotation speed of the work is about 0.7 to 2.7 rotations per second, the rotation speed is 0.4 to 1.3 seconds per rotation. From this, the time for the work to rotate 1 ° is from 1.1 msec (msec is one thousandth of a second) to 3.6 msec, so if load control is performed at 10 ° intervals (36 times per rotation). The control cycle is about 11 ms to 36 ms. Since the control cycle of rolling or the like is usually about 50 milliseconds, the control cycle is slightly faster than this, but it can be sufficiently implemented by improving the performance of the control computer and drive mechanism.

As described above, since the drive mechanism of the flat deformation prevention device, the gripping tool, and the support mechanism for the workpiece end are disposed, the flat deformation of the work can be prevented, and a highly accurate dimensional product can be manufactured.

The effect of the thread rolling apparatus of the eighth invention will be described.

FIG. 12 is an explanatory view showing an embodiment of an embedded flat deformation preventing device installed on a round die mounting base. In the case of a round die, the structure of the device is substantially the same by using the molded body as a screw body in the seventh aspect of the present invention.

FIG. 13 is an explanatory view showing one embodiment of a rolling processing apparatus for a rolled body disclosed in the eighth invention, and a flat die mounting base of a worm flat die rolling machine disclosed in Patent Document 6). Column) was modified and a flat deformation prevention device for the workpiece was installed.

In the embodiment, a drive mechanism, a gripping tool, and a support mechanism for the workpiece end are arranged so that the principle of preventing flat deformation shown in FIG. 14 works from the start to the end of the rolling process. The drive mechanism may be installed on any of a die, a die mounting base (column), and a structural member (column base or the like) that supports the die.

In the embodiment, like the round die, the maximum capacity of one drive mechanism is set to about 2 tons, so that when the hydraulic source of 20 kg / cm ² is used, the cross-sectional area of the cylinder is required to be at least about 100 cm ² . In the embodiment shown in FIG. 12, the drive mechanism is embedded in a die mounting base (column) that can approach the die due to the installation space.

In the embodiment, the both end portions of the workpiece are loaded by a driving mechanism via a gripping tool. The work being rolled is held between dies and a forming load of 10 tons or more is applied. Further, the work is constrained to rotate freely from both sides with the center of both end faces at the center, and machining is continued in a macroscopically stable posture even without a flat deformation preventing device for the work. Since the drive mechanism of the flat deformation prevention device of the workpiece acts a load whose direction changes in the direction of the molding load acting from the die to the workpiece, if the friction force with the workpiece is ignored, the macroscopic workpiece posture will not be disturbed Absent.

In general, a die can ignore the bending deflection in the axial direction of the workpiece. Therefore, maintaining the relative position such as the inclination and distance between the contact surface of the die and the central axis of the workpiece shown in FIG. Is important to. The posture control of the workpiece is performed according to the operation principle of the flat deformation prevention device shown in FIG.

That is, since the posture control of the workpiece is control of the load acting on the workpiece, it is necessary to measure the load acting on the workpiece. A load meter (not shown) is installed to measure the pressing force of the die and the pressing force or pulling force of each drive mechanism of the flat deformation prevention device.

Assuming that the rotation speed of the workpiece is the same as in the case of the round die, it is about 0.7 to 2.7 rotations per second, and is 0.4 to 1.3 seconds per rotation. Thus, since the time for the work to rotate 1 ° is 1.1 to 3.6 ms, if the load is controlled every 10 ° as in the case of the round die, the control period is about 11 to 36 ms. Since the control cycle of rolling or the like is usually about 50 milliseconds, the control cycle is slightly faster than this, but it can be sufficiently implemented by improving the performance of the control computer and drive mechanism.

As described above, since the drive mechanism of the flat deformation prevention device, the gripping tool, and the support mechanism for the workpiece end are disposed, the flat deformation of the work can be prevented, and a highly accurate dimensional product can be manufactured.

The effect of the thread rolling apparatus of the ninth invention will be described.

FIG. 15 is an explanatory view of a mechanism for supporting both ends of a work disclosed in the ninth aspect of the present invention. As shown in FIG. 14, the pushing force or pulling force from the workpiece flattening prevention device is transmitted to the workpiece via the support mechanisms at both ends of the workpiece gripped by a gripping tool (not shown). The support mechanism at both ends of the workpiece is a three-layered cylinder, and a linear motion bearing that slides in the axial direction is installed between an outer cylinder that contacts the gripping tool and the intermediate cylinder, and an inner cylinder and an intermediate cylinder (not shown) that contact the workpiece A bearing that slides in the circumferential direction is installed between the two.

Therefore, when the outer cylinder is fixed to the gripping tool, the rotation of the work by the die is absorbed by the bearing between the inner cylinder and the intermediate cylinder, so that the pushing force or pulling force by the gripping tool disturbs the rotation of the work. There is no. Further, since the movement of the workpiece in the axial direction caused by the walking is absorbed by the bearing between the outer cylinder and the intermediate cylinder, the pushing force or the pulling force by the gripping tool does not disturb the walking of the workpiece.

As the linear motion bearing and the bearing, a bearing having a rolling element or a bearing by a fluid lubricating film can be used. In addition, the case of a three-layer structure has been described as a mechanism for supporting both ends of the workpiece. However, the outer cylinder and the inner cylinder may be omitted, and the number of layers may be changed depending on usage conditions such as a bearing installation method and load. . For example, when a bearing having both functions of a linear motion bearing and a bearing is used, the bearing need not have a three-layer structure, and may have one or two layers.

According to the thread rolling apparatus of the ninth aspect of the present invention, even if a pressing force or a pulling force is applied to the workpiece by the driving mechanism of the workpiece flat deformation prevention device, the workpiece does not deform abnormally. Products with high-precision dimensions can be processed.

The effect of the thread rolling apparatus of the tenth invention will be described.

FIG. 14 is an explanatory view showing the operating principle of the flat deformation preventing device for a workpiece. When the position of the incomplete thread portion is displayed at an angle θ around the center axis of the work fixed in space, for example, the load by the drive mechanism of the work flattening prevention device at θ = 0 °, θ = 90 °, θ = 180 ° Must be optimally controlled. For this purpose, it is necessary to track the position θ of the incomplete screw portion and transmit the position θ of the incomplete screw portion to the control system of the drive mechanism of the flattening prevention device.

A rotary encoder is known as a typical work rotation pulse detection mechanism. By attaching a rotary encoder to the rotating shaft of the workpiece, it is possible to measure the circumferential position and rotational speed and output it as an electrical signal.

In the work feeding bases disclosed in Patent Document 1), Patent Document 6), and FIG. 15, the centers of both end faces of the work are rotatably supported by the center, so that it is difficult to attach the rotary encoder with the structure as it is. However, in the push-torsion type work feed platform disclosed in FIG. 19, a rotary encoder can be attached to an axis extending the work in order to rotationally drive the work. As in this example, it is possible to take out the rotation of the workpiece with a shaft and install a rotational position measuring device such as a rotary encoder on this shaft.

Also in the center-supported workpiece feeding table disclosed in FIG. 15, as described in the thread rolling method of the fourth aspect of the present invention, a mark is given to a part of the workpiece and this is detected by the sensor. Thus, the rotational position can be measured.

As the workpiece rotation pulse detection mechanism, as described in the thread rolling method of the fourth aspect of the present invention, the pressing force of the die and the load of the driving mechanism of the workpiece flattening prevention device are measured with a load meter. A mechanism for detecting a periodic variation in load is known.

By applying these existing detection mechanisms, the circumferential position of the incomplete thread portion can be detected. Therefore, by transmitting the position in the circumferential direction of the incomplete thread portion to the control system of the flat deformation prevention device of the workpiece, it becomes possible to process the dimensional shape with high accuracy.

The effect of the thread rolling apparatus of the eleventh invention will be described.

FIG. 19 is an explanatory view showing the structure of a push-twist type work feed base disclosed in the eleventh aspect of the present invention. The main structure has been described in the thread rolling method disclosed in the fifth aspect of the present invention. The structure of the device is simplified and rational if a load mode that is effective for uniform deformation of the workpiece is selected from the axial pushing force (back pressure), the torsional torque around the shaft, and the bending moment in the axial direction. Is self-explanatory. In addition, when the torsional torque around the shaft is applied to both ends of the workpiece, the rotation drive mechanism may be installed on both sides of the workpiece.

FIG. 4 is an explanatory view showing the positional relationship per cycle of the opening / closing of the die and the work feed table by the rolling machine of the round die. The workpiece load mechanism in FIG. 19 may interfere with the die when the workpiece feed base moves when the workpiece is attached or detached. In order to prevent this, a mechanism for greatly opening and closing the dice is necessary, but the drive mechanism for pushing the dice tends to have a low opening and closing speed in order to increase the pushing force. Therefore, it is preferable to provide a die opening / closing mechanism that can move at high speed without requiring a load.

Similarly, the load mechanism of the workpiece in FIG. 19 is preferably provided with a mechanism for speeding up the opening and closing of the workpiece. Further, the attachment and support mechanism at both ends of the work requires center axis alignment by the work center mechanism. A taper type fitting can be applied, but a cleaning measure such as air blowing is required so that foreign matter such as dust does not adhere to the fitting surface.

The work load mechanism of FIG. 19 operates in synchronization with the rotation of the work in accordance with the pushing amount of the work. Further, when the die feed direction changes, the torsion torque selects an appropriate direction according to this.

The load of the work is load control of the pressing force, but the length is fed back so that the work length falls within the finished dimensions. For this purpose, load sensors and position sensors at both ends of the work are installed. The length of the workpiece can be obtained from the amount of movement of the position sensors at both ends and the initial length of the workpiece. Further, a mechanism for directly measuring the length of the workpiece may be used.

According to the thread rolling apparatus of the eleventh aspect of the present invention, the axial displacement constraint is equalized and the variation in the axial deformation of the workpiece is suppressed, so that highly accurate dimensional shape machining is possible.

The effect of the thread rolling apparatus of the twelfth invention will be described.

The mechanism for making the frictional constraint uniform in the thread rolling method of the sixth aspect of the present invention has been described. In the rolling process, a dedicated rolling oil seems to be used for lubrication. Therefore, a specified lubrication mechanism may be applied to the rolling machine. Further, when rolling a large screw of a module such as a worm, the apparent advance angle is controlled as disclosed in Patent Document 2) and Patent Document 6). In this case, since there is a report that the processing temperature of the workpiece is difficult to rise, thermal strain is also reduced.

In order to further reduce the thermal strain, an emulsion obtained by diluting a rolling oil or a lubricant with water may be sprayed directly on the contact surface of the workpiece or the die. In that case, a lubrication system for circulating the emulsion may be installed.

When applying vibration by a vibration device, it seems that it is not common, so install a vibration transmitter. In the case of ultrasonic vibration, a horn or the like is installed in order to cause a local relative displacement of the contact interface by causing a workpiece or die to resonate with the vibration transmitter. The resonance effect varies greatly depending on the location and direction of vibration. The addition method with large resonance is narrowed down in advance at various positions.

In addition, since the thread rolling apparatus of the present invention has various drive mechanisms such as die pressing, work flat deformation prevention, work axis direction restraint, etc., vibrations of relatively high frequency can be superimposed on these loads. . As a result, the vibration transmitter can be vibrated without being installed in the vicinity of a work where space is limited and environmentally strict.

By applying the thread rolling apparatus according to the twelfth aspect of the present invention, it is expected that random walks and the like are reduced due to uniform deformation of the workpiece.

The effect of the thread rolling apparatus of the thirteenth invention will be described.

FIG. 20 is an explanatory view showing the flow of the rolling control system for a rolling body or screw disclosed in the thirteenth aspect of the present invention. Collect measurement data while rolling with a rolling machine. The measurement data is transmitted to the control device, and a drive mechanism command is generated according to the control logic and transmitted to the rolling machine. Each drive mechanism of the rolling machine receives a command and changes the rolling conditions by a predetermined amount. That is, the basic control flow constitutes a typical feedback control loop.

The measurement data includes at least one of a flat load, a gap between the die and the workpiece, back pressure at both ends of the workpiece, torque at both ends of the workpiece, rotational positions at both ends of the workpiece, and the length of the workpiece. Moreover, the state of the process of a rolling machine is grasped | ascertained by combining with the measurement data of the die displacement, the die load, the die shaft torque, the die tilt angle, and the workpiece position disclosed in Patent Literature 1) and Patent Literature 3). Further, by combining with the control mechanism disclosed in Patent Document 6), the state of the process of the flat die rolling machine can be grasped.

The drive mechanism commands include one or more of gripping and pulling of the workpiece gripping, axial pushing and pulling of the workpiece end, and twisting around the axis of the workpiece end. Moreover, by combining the tilt angle of the rotating shaft of the die disclosed in Patent Document 1) and Patent Document 3), the forward / reverse switching position of shuttle rolling, and the cutting (pushing speed and die rotating speed ratio), Can be controlled. Furthermore, a flat die rolling machine can be controlled by combining with the control mechanism disclosed in Patent Document 6).

Since these control variables are variables introduced to control the new mechanisms of FIGS. 12, 13, 15, and 19, they are necessary to properly control these new mechanisms. By controlling the workpiece flat deformation prevention device, the axial back pressure and the torsion torque, it is possible to select a deformation path of the workpiece with less excessive deformation.

By applying the thread rolling apparatus of the thirteenth aspect of the present invention, it is expected that the random walk and the like are reduced by uniformizing the deformation of the workpiece.

The effect of the thread rolling apparatus of the fourteenth invention will be described.

FIG. 20 is an explanatory diagram showing a flow of a rolling control system for a rolling body or a screw body. In addition to the feedback control loop disclosed in the thirteenth aspect of the present invention, a control model and / or a learning control function are provided. The control model simulates the rolling process, has multivariable inputs and multivariable outputs, and constitutes a multivariable control system in cooperation with the control system body.

A rolling machine incorporating the control system disclosed in Patent Literature 1) and Patent Literature 3) sets a target value for a state quantity measured by a sensor, and sets a correction amount to the drive mechanism so as to approach the target value. Perform instructed fadeback control. The rolling control system of FIG. 20 is also substantially the same as the control system disclosed in Patent Document 1) and Patent Document 3) in terms of individual sensors and drive mechanisms. Therefore, hardware can be easily constructed by diverting existing rolling machines and adding insufficient mechanisms.

A significant feature of the rolling control system of FIG. 20 is that the target value of the control is generated so that all the drive mechanisms cooperate in order to optimize the various state quantities of the rolling machine being processed. For this reason, changes in individual state quantities must be reflected in all drive mechanism commands, and a multi-variable control system is employed. When the control period exceeds about 11 ms to 36 ms, the variable mechanism of the multivariable control system may be reduced by using a drive mechanism having a weak interaction as a control system disclosed in Patent Literature 1) and Patent Literature 3).

As discussed in FIG. 5, a deformation path for minimizing excess deformation is determined by plastic theory for a controlled object in which the dimensions and shape of each part of the workpiece are deformed in a three-dimensionally complex manner by pressing a die. Based on the multivariable control system, the control target value of each drive mechanism is instantly generated. If the target value is determined, each drive mechanism is operated in the same manner as in the control systems disclosed in Patent Document 1) and Patent Document 3) to perform target processing.

The control model is the core technology of multivariable control, and it handles deformation path calculation and control target value generation. Further, the learning control function identifies the model parameters of the control model so as to be compatible with the rolling machine that is the control target. Therefore, since the control model faithfully reflects the object to be controlled by repeating manufacturing, an improvement in the accuracy of the dimensional shape of the product is expected.

Random walk, which is one of the important specification items of products, is an error in which the dimensional shape error of each screw thread is comprehensively measured. Random walks are difficult to measure during rolling, so lots are evaluated by sampling inspection of the molded product after processing. In order to reflect the evaluated result in the condition setting of the rolling process, a new deformation history with less surplus strain is set as the three-dimensional deformation state of the work and reflected in the target value of the control system.

  By incorporating this work as a learning function of the control system, automation of processing is promoted. The model parameters of the control model can be optimized by the learning function.

In the control system centering on the classic control logic with one input and one output disclosed in Patent Document 1), Patent Document 3) and Patent Document 6), it is difficult to consider the influence between control variables. For this reason, it has been difficult to comprehensively control the new mechanism shown in FIGS. 12, 13, 15, and 19 under optimum conditions.

In the rolling control system of the rolling body or screw body disclosed in the fourteenth aspect of the present invention, as described above, each drive mechanism is coordinated to easily realize an ideal deformation state with little excess deformation. Therefore, reduction of random walks and the like is expected by making the deformation of the workpiece uniform.

The effect of the molded body of the rolled body according to the fifteenth invention will be described.

The molded product formed by rolling using the rolling method disclosed in the first aspect of the present invention and the rolling processing apparatus disclosed in the seventh aspect of the present invention is the operating principle of the flat deformation preventing apparatus for workpieces disclosed in FIG. Act. Therefore, the effect of preventing the occurrence of flat deformation of a large screw of the module disclosed in FIG. 7 is great.

The molded body of the rolled body according to the fifteenth aspect of the present invention enables processing with a highly accurate dimensional shape.

The effect of the molded body of the screw body according to the sixteenth invention will be described.

A formed body of a screw body rolled using the rolling processing methods disclosed in the second to sixth inventions and the rolling processing apparatus disclosed in the eighth to fourteenth inventions is disclosed in FIG. The working principle of the flat deformation prevention device for the workpiece acts. Therefore, the effect of preventing the occurrence of flat deformation of a large screw of the module disclosed in FIG. 7 is great.

The molded body of the screw body according to the sixteenth aspect of the present invention enables highly accurate dimensional processing.

The effect of the molded body of the screw body according to the seventeenth invention will be described.

The shape of the tooth bottom between the teeth of the workpiece is expressed by a piecewise continuous curve of a monotonic function having no inflection point. When viewed in the direction of the flow of the material that plastically flows along the shape of the thread groove of the die during the rolling process, the material tends to draw smooth streamlines without inflection points. If the shape of the bottom of the tooth (the groove bottom of the screw) has an inflection point, the material tends to flow smoothly at that portion, which tends to cause an unnatural plastic flow that peels from the die.

Also, an ideal screw shape that smoothly changes with the groove bottom of the screw as a vertex can be satisfactorily approximated by using a piecewise and continuously changing line. After obtaining a flow direction of the material by performing a preforming test or the like, if a smooth screw shape is designed in this direction, a screw shape close to ideal can be rolled.

The worm disclosed in Patent Document 1) is used in combination with a resin gear as a power steering component for automobiles. In this case, in order to optimize the geometric shape of the soft resin teeth and improve the strength, the curved tooth thickness of the worm is assumed to be smaller than the interval between the roots.

In recent years, machine parts are designed by CAD using a computer and processed by numerical control by CAM. Therefore, even if a reasonable shape based on plastic theory is adopted without being limited to shapes such as arcs and straight lines that are easy for humans to draw, workability is not deteriorated because it can be easily absorbed by CAD or CAM. The advantage of forming an ideal thread shape is great.

According to the molded body of the screw body of the seventeenth aspect of the present invention, highly accurate dimensional shape processing is possible.

  The present invention relates to a rolling method, a processing apparatus, and a molded body for rolling a rolled body or a screw body.

  In order to reduce the excess strain introduced into the compact by rolling, the hardware features a flat deformation prevention device and an axial load mechanism, and a deformation path that reduces excess strain is realized. The next generation intelligent rolling machine was conceived by fusing software characterized by applying multivariable control.

  And the Example was disclosed for the shaping | molding of the worm | worm for power steering of the motor vehicle which a tooth | gear walk of a tooth | gear easily generate | occur | produces because a module is large. The embodiment is one of the best modes for carrying out the present invention, and the disclosed technique is not only a worm by adjusting a control system, but also high-precision dimensions of general screw bodies and various rolled bodies. A remarkable effect is also expected for shape molding.

  For this reason, the rolling method, processing apparatus, and molded body for rolling the rolled body or screw body of the present invention realize natural material deformation with little excess deformation, so that processing of a highly accurate dimensional shape is possible. Is possible.

It is explanatory drawing which shows the external view of the round die rolling machine of a prior art. It is explanatory drawing of the control system of the round die rolling machine of a prior art. It is explanatory drawing which shows the rolling process by the round die rolling machine of a prior art. It is explanatory drawing which shows the positional relationship of the workpiece | work and die per cycle in the round die rolling of a prior art. It is explanatory drawing which shows the external appearance before and behind a process of a workpiece | work of a prior art, and a three-dimensional deformation state. It is explanatory drawing which shows the error by the flat deformation of the pitch cylindrical diameter and outer diameter of the screw which arise in a prior art. It is explanatory drawing which shows the generation | occurrence | production mechanism of the flat deformation of the big screw of the module of a prior art. It is explanatory drawing which shows the generation | occurrence | production mechanism of the non-uniform | heterogenous deformation in the bending bending return of a wire. It is explanatory drawing which shows the rolling process of the thread of the worm material with a notch of a prior art. It is explanatory drawing which shows the general appearance and function of the cam for rolling pressure adjustment of a prior art. It is explanatory drawing which shows the inclination of the workpiece | work flatness of a prior art, and a workpiece | work center axis | shaft in the case of a single thread | screw. It is explanatory drawing which shows the characteristic of the embedding type flat deformation prevention apparatus in the round die mounting base of this invention. It is explanatory drawing which shows the characteristic of the embedding type flat deformation prevention apparatus in the flat die mounting base of this invention. It is explanatory drawing which shows the operating principle of the flat deformation | transformation prevention apparatus of this invention in the case of a single thread | screw. It is explanatory drawing which shows the workpiece | work both-ends support mechanism of the rotation and slide freedom of this invention. It is explanatory drawing which shows the incomplete thread part tracking method of this invention. It is explanatory drawing which shows the axial length increase phenomenon of the workpiece | work of a prior art. It is explanatory drawing which shows the twist deformation simulation result of the screw end part by the finite element analysis of a prior art. It is explanatory drawing which shows the mechanism of the push-torsion type work feed stand of this invention. It is explanatory drawing which shows the rolling control system of the rolling body or screw body of this invention.

1, 2, 3, 4, 5 Order of twist rotation of both ends of work 10 Round die mounting base 11 Round die 12 Work 13 Driving mechanism 14 of work flat deformation prevention device Work end support mechanism 15 Holding tool 16 Die moving base 17 Beam shaft 20 Column 21 Flat die 22 Slide table 23 Column base 30 Center 31 Work end support mechanism 32 Linear motion bearing of work end support mechanism 33 Bearing of work end support mechanism 40 Drive mechanism 41 of work axial force Drive mechanism 42 Torque transmission shaft 43 Push base 44 Beam shaft

Claims (17)

A pushing force and / or a pulling force is applied between the workpiece and the die, the die mounting base, or the structural member supporting the die in synchronization with the rotation of the workpiece at an arbitrary die pushing position. The rolling process method for a rolled body, characterized in that the relative position between the workpiece and the die is maintained in a target state, and the workpiece is rolled by the die. The die is a round die or a flat die, and the workpiece and any of the die, the die mounting base, and the structural member that supports the die are synchronized with the rotation of the workpiece at an arbitrary pushing position of the die. Rolling process of a screw body characterized by holding a relative position between the workpiece and the die in a target state by applying a pushing force and / or a pulling force, and rolling the workpiece with the die Method. While supporting the rotation around the center axis of the work and the movement in the direction of the center axis, the pressing force and / or between the work and the die, the die mounting base, and the structural member supporting the die Or the pulling force is loaded, The rolling process method of the screw body of Claim 2 characterized by the above-mentioned. 4. The circumferential position of the incomplete thread portion of the workpiece is tracked by detecting a rotation pulse of the workpiece and / or detecting a load variation, and synchronized with the rotation of the workpiece. A method of rolling a screw body. The rolling work is performed while applying an axial force and / or a torsional torque about the axis to the workpiece, and a bending moment of the workpiece central axis is applied as desired. A method of rolling a screw body. 6. The thread rolling method according to claim 2, wherein forced lubrication with coolant of the workpiece and / or vibration with a vibration device is applied. Drive in which a pressing force and / or a pulling force is applied between any one of the workpiece, the die, a mounting base of the die, and a structural member supporting the die in synchronism with the rotation of the workpiece at an arbitrary die pushing position. A rolling device for a rolled product, characterized by having a mechanism. The die is a round die or a flat die, and any one of the workpiece and the die, a mounting base for the die, and a structural member for supporting the die in synchronization with the rotation of the workpiece at an arbitrary pushing position of the die A screw thread rolling apparatus having a drive mechanism for applying a pushing force and / or a pulling force between them. 9. The thread rolling apparatus according to claim 8, further comprising a support mechanism at both ends of the workpiece that supports the rotation around the center axis of the workpiece and the movement in the direction of the center axis. 10. The thread rolling apparatus according to claim 8, further comprising a rotation pulse detection mechanism and / or a load fluctuation detection mechanism for detecting an incomplete thread portion of the workpiece. 11. The drive mechanism according to claim 8, further comprising an axial force and / or a torsional torque around the shaft, and a bending mechanism that loads a bending moment of the central axis of the workpiece as desired. Screw body rolling processing device. The thread rolling apparatus according to any one of claims 8 to 11, further comprising a forced lubrication mechanism using the coolant of the workpiece and / or a vibration mechanism for vibrating the workpiece. As measurement data, any one of flat load, gap between the die and the workpiece, back pressure at both ends of the workpiece, torque at both ends of the workpiece, rotational positions at both ends of the workpiece, and length of the workpiece Including a control system including one or more of a push / pull of the work gripping part, an axial push / pull of the end of the work, and a torsion around the axis of the end of the work as a drive mechanism command. The thread rolling apparatus according to any one of claims 8 to 12. 14. The thread rolling apparatus according to claim 8, wherein the control system is a multivariable control system and has a control model and / or a learning control function. A formed body of a rolled body, characterized by being produced by the rolling method according to claim 1 and / or the rolling apparatus according to claim 7. A molded body of a screw body, characterized by being manufactured by the rolling processing method according to claim 2 and / or the rolling processing apparatus according to claims 8 to 14. The shape of the tooth bottom between the teeth of the workpiece is expressed by a piecewise continuous curve having a monotonic function having no inflection point, and the tooth thickness is smaller than the interval between the tooth bottoms if desired. A molded body of the screw body according to 1.

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