JPH0618671B2 - Crown roller manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a crown roller without cutting, and in particular, a method for manufacturing a crown roller capable of obtaining high roundness and surface accuracy without using a molding die. It is about.

(Prior Art) In electrophotographic copying machines and printers, a heat roll type fixing device has been put into practical use. In this heat roll fixing device, a heat roll having an inverted crown is widely used to improve paper passing performance. Has been done. This heat roll uses an aluminum cored bar roller with an outer peripheral shape of an inverted crown, the center roller part is covered with high release fluororesin or silicone rubber, and bearings and drive gears are provided at both ends of the roller part. A journal portion is formed for connection.

Conventionally, a core metal roller having an inverted crown shape has been manufactured by cutting with a lathe. In this cutting process, the outer circumference of the roller is cut using a lathe using an aluminum tube having a diameter larger than the reference outer dimension, and a crown roller having a desired crown ratio is manufactured.

(Problems to be solved by the invention) The manufacturing method by cutting has an advantage that a high roundness can be obtained, but it is necessary to perform cutting by using a thick-walled raw pipe, which causes chips to be produced. There was a drawback that the cost was high. Moreover, when aluminum is used as the roller material, since aluminum for general use is a difficult-to-cut material, it is necessary to use an aluminum material that is easy to cut in order to form an inverted crown shape by cutting. Since the aluminum material that is easy to process is expensive, the manufacturing cost is further increased.

Bulge processing is another method of manufacturing crown rollers than cutting. However, in the bulge processing, since the raw pipe to be molded is not rotated, it is the actual situation that sufficient roundness that can be practically used cannot be obtained. Moreover, since the molding is performed using the molding die, the manufacturing cost becomes high. In addition, as another manufacturing method, there is a swaging method, but as with the bulge processing method, sufficient processing accuracy cannot be obtained,
Moreover, there is a drawback that unnecessary vibration and noise are generated during manufacturing.

Therefore, the object of the present invention is to eliminate the above-mentioned drawbacks, to further reduce the manufacturing cost, to obtain high roundness and high surface accuracy, and to achieve high precision without using a molding die. A method of manufacturing a crown roller capable of manufacturing a crown roller having a crown rate.

(Means and Actions for Solving the Problems) A method for manufacturing a crown roller according to the present invention is
When manufacturing crown rollers for heat rolls used in heat roll fixing devices, where the roller outer diameter continuously increases or decreases from approximately the center of the central axis toward both ends, grip both ends of the pipe material to be processed. And a clamp member, which is arranged at equal intervals along a circumferential direction of the central axis in a plane orthogonal to the central axis connecting the clamp members, and is supported rotatably about a rotation axis parallel to the central axis. , At least two forming rollers that move integrally in a direction parallel to the central axis and that move in a relationship in which the distances from the central axis are equal to each other along a direction orthogonal to the central axis; Using a spinning molding machine having a pressing means for pressing against, both ends of the pipe material are respectively gripped by the clamp members, At least one of the material and the forming roller is rotationally driven, and the forming roller is moved in a direction parallel to the central axis of the tubular material while being pressed against the tubular material, and the forming roller is moved from the central axis during the movement. Is moved so as to change continuously, and the outer peripheral surface of the pipe material is formed into a crown shape while maintaining the inner peripheral surface of the pipe material in a free state.

When both ends of the pipe material to be molded are clamped and rotated and the forming roller is pressed against the outer peripheral surface of the pipe material while being rotated, the pipe material is plastically deformed only in the inner peripheral direction. The amount of deformation is accurately defined by the distance from the central axis of the pipe material to the forming roller. Therefore,
By moving the forming roller in the radial direction of the pipe material and also in the direction parallel to the central axis of the pipe material during this movement, a crown roller whose outer diameter dimension increases and decreases in accordance with the distance in the central axis direction is provided. It can be manufactured. On the other hand, as in the case of the spatula drawing process, a method of pressing a spatula against the outer peripheral surface of the pipe material and plastically deforming along the outer peripheral surface of the mold can be considered. However, since the outer diameter of the crown roller increases and decreases or decreases and increases in accordance with the distance in the central axis direction, the molding method using the mold (core) causes the crown roller to be separated from the mold after molding and the molded product. In principle, the spinning molding method using a die cannot be applied to the production of crown rollers.
For this reason, in the present invention, a crown shape is formed without using a forming die.

On the other hand, since the pipe material before forming does not have perfect roundness, when an attempt is made to plastically deform it by using one forming roller, the outer peripheral surface of the pipe material is restricted from only one direction, so that the pipe material is not bent. However, the plastic material cannot be satisfactorily plastically deformed, and the deviation of the outer peripheral surface of the tube material itself remains as it is, so that sufficient circularity as a roller cannot be obtained. Therefore, in the present invention, at least three forming rollers are used, and these forming rollers are arranged at equal intervals along the circumferential direction of the pipe material. For example, when using three forming rollers,
A force that displaces the pipe material in the opposite direction is generated from one forming roller, but since the pipe material is regulated by the other forming roller arranged on the opposite side, the three forming rollers oppose each other in the radial direction with respect to the pipe material. The pressing force acts in the direction, and while the pipe material rotates, the pipe material moves to the inner peripheral side and the circularity of the pipe material is gradually corrected. As a result, a crown roller with high roundness can be manufactured without using a molding die (core). Therefore, in the present invention, two or more forming rollers are arranged at an equal angle in a plane orthogonal to the central axis of the pipe material, and the pressing force from each forming roller is received by the other forming roller, and the pipe material is received from at least three directions. The pipe material is plastically deformed in the radial direction while the outer peripheral surface of the pipe is regulated. Then, while moving the forming roller in the central axis direction of the pipe material, the forming roller is also moved in the radial direction of the pipe material so that the distance from the central axis line continuously changes, and the pipe material is plastically deformed to its inner peripheral side to form a crown shape. Mold. In this case, the tube material may be driven to rotate and the forming roller may be driven to rotate, or the forming roller may be driven to rotate and the tube material may be driven to rotate. Further, a motor may be connected to each of the pipe material and the forming roller, and the pipe material and the forming roller may be forcibly driven while maintaining the peripheral speed of the pipe material and the peripheral speed of the forming roller equal to each other. In this case, it can be easily controlled by using a constant peripheral speed device.

Further, in the present invention, the forming roller is constituted by a crown roller having a desired positive or negative crown shape, and these forming rollers are centered in a relation that the distance from the central axis of the pipe material is equal along the radial direction of the pipe material. Move toward the axis. When the forming roller is pressed and moved in the radial direction of the pipe material, the pipe material is plastically deformed in the inner peripheral direction along the outer shape of the forming roller. It is possible to manufacture a crown roller having a crown shape. That is, when manufacturing a negative crown roller (reverse crown roller), a negative crown roller having a desired crown ratio can be manufactured only by pressing the positive crown roller against the pipe material. In this case, since the forming roller can be formed into a crown shape without moving in the direction parallel to the central axis of the pipe material, the manufacturing process can be facilitated and the manufacturing time can be further shortened. In this case, since the pipe material and the forming roller are in line contact with each other, a high pressing force acts on the pipe material. Therefore, when the pipe material is rotationally driven and the forming roller is driven to rotate, a large load is generated on the rotational drive of the pipe material. Therefore, in this case, it is preferable to rotatably support the pipe material and drive and rotate the forming roller, or to drive and rotate both the pipe material and the forming roller. In this way, by clamping both ends of the pipe material and plastically deforming the pipe material in the inner circumferential direction while rotating the pipe material, a crown roller with high roundness can be manufactured by a simple operation without using a molding die (core). be able to.
Moreover, since it is formed without cutting, it can be manufactured from a thin-walled pipe material and an inexpensive pipe material of difficult-to-cut material can be used.

(Example) FIG. 1 is for explaining a method for manufacturing a crown roller according to the present invention, and FIG. 1a is a diagrammatic sectional view taken along a plane including a central axis of a pipe material to be molded. 1b is a schematic sectional view taken along the line I-I of FIG. 1a. In this example, an aluminum base pipe is used as a pipe material to be molded, and a reverse crown roller is produced from this aluminum base pipe. Both ends of the central axis l of the pipe material 1 are respectively held by the clamp members 2a and 2b of the spinning molding machine. Then, one clamp member 2a is connected to a motor (not shown), and the pipe material 1 is rotated about its central axis l. The forming machine has three forming rollers 3 to 5 for plastically deforming the pipe material 1, and these forming rollers are equally spaced along the circumferential direction in a plane orthogonal to the central axis line 1 of the pipe material 1. Deploy. In addition, in FIG. 1A, for the sake of clarity, only two forming rollers 3 and 4 of the three forming rollers are shown to face each other. Each forming roller 3
Nos. 5 to 5 have their rotation axes 3a to 5a extending parallel to the central axis l of the pipe material, and a supporting member (not shown) of the spinning molding machine.
Each is rotatably supported by. These three forming rollers 3 to 5 are made of tool steel and have a diameter of 12
It has a roller shape with a diameter of 0 mm and a width of 25 mm, and as shown in FIG. The forming machine is equipped with a pressing device such as a hydraulic device or a ball screw, and this pressing device is connected to the supporting member of the forming roller so that each forming roller can be pressed against the pipe material 1 with a pressing force of about 2 to 10 tons. To configure. The three forming rollers 3 to 5 reciprocate in a direction parallel to the central axis l of the pipe material 1, and also reciprocate in the radial direction of the pipe material. When moving in the direction parallel to the central axis, the three forming rollers move integrally, and when moving in the radial direction, the distances from the central axis 1 are kept equal to each other. It shall move in a direction approaching the central axis l and in a direction moving away from it. Then, the forming rollers 3 to
The radial movement amount of 5 is controlled based on the movement amount in the direction parallel to the central axis. It should be noted that control of these movement amounts is performed by a programmable control device provided in the spinning molding machine.

Next, a method of forming the crown roller will be described. As an example, a reverse crown roller for a heat roll having a standard outer diameter of 60φ and a crown amount of 0.1 mm is manufactured. As the pipe material, an aluminum base pipe having an outer diameter of 60.5φ and a length of 330 mm is used. The areas of 10 mm and 20 mm on both ends of the raw pipe are journals with an outer diameter of 60φ.

First, the molding conditions are input to the controller of the forming machine. In this example, the rotational speed of the pipe material 1 is 1000 rpm and the moving speed of the forming roller in the central axis direction is 10 rpm.
Set 00 mm / min and radial movement speed to 0.33 mm / min. Then, the three forming rollers are moved from one end side to the other end side in the central axis direction of the pipe material, and are moved only along the central axis direction while moving 10 mm from the one end side. Move it while maintaining the position at 30 mm from. Next, after moving 10 mm, the forming roller is moved in the direction of the central axis and is also moved in the radial direction in the direction approaching the central axis at the above moving speed. Furthermore, 150mm
After the movement, it is moved in the direction of the central axis as it is, and in the radial direction, on the contrary, it is moved in the direction away from the central axis at the above speed. Next, after moving an additional 150 mm, the radial movement is stopped and the speed is 20 mm at the same speed in the direction of the central axis.
To move. These conditions are input to the controller of the forming machine.

After inputting the molding conditions to the controller, both ends of the pipe material to be molded are gripped by the clamp members of the forming machine. Next, the motor of the forming machine is driven to rotate the pipe material 1 about its axis. Next, the forming roller driving device provided in the forming machine is started, and the three forming rollers are moved in the radial direction up to a position 30 mm from the central axis to press-contact the outer peripheral surface of the pipe material 1 and move in the central axis direction. Let The tube material 1 and each forming roller are in point contact with each other, and each forming roller is driven to rotate with respect to the tube material 1. At this time, since the three forming rollers act evenly on the outer peripheral surface of the pipe material,
A uniform roller portion having an outer diameter of 60φ is formed. Next, as shown in FIG. 2A, when the forming roller moves in the radial direction as well as in the direction of the central axis, the pipe material is plastically deformed in the radial direction, and the outer diameter gradually decreases. A roller portion is formed. Further, as it passes through the central portion of the pipe material, as shown in FIG. 2B, the forming roller moves in a direction away from the central axis of the radial direction, so that the plastic deformation amount in the radial direction gradually decreases and the outer diameter dimension becomes smaller. A gradually increasing roller portion is formed.

While the forming roller moves in the direction parallel to the central axis, the tubular member rotates while being pressed against the outer three sides of the outer peripheral surface thereof, so that the tubular member is not only plastically deformed to the inner peripheral side, but also
The roundness of the pipe material is gradually corrected by the three forming rollers.

3A and 3B show the structure of a heat roll manufactured using the crown roller manufactured by the manufacturing method described above. Both ends of the heat roll 10 are journal parts 11 and 12, and a release layer 13 such as fluororesin or silicon rubber is formed between these journal parts. Journal section 11 and 12
Grooves 11a and 12a for mounting a retaining ring are formed in each of them, and a key groove 14 for connecting a drive gear is formed in the journal 12. In using this heat roll, bearings are attached to the journals 11 and 12, respectively, a drive gear is attached to the journals, and then a retaining ring is attached to each journal to prevent the bearings from slipping out. According to this structure, it is possible to manufacture an inverted crown type heat roll having an extremely simple structure.

FIG. 4 shows a modified example of the method for manufacturing a crown roller according to the present invention. FIG. 4a is a sectional view showing the constitution of each member before joining the boss members, and FIG. FIG. 4C is a sectional view showing a state after the final joining step. In this example, the roller body 20 having a crown shape is prepared by the method described above, and then the recesses 21 and 22 are formed at both ends of the roller body 20, respectively. Next, as shown in FIG. 4B, the boss members 23 and 24 are fitted and fixed in the respective recesses by press fitting or shrink fitting. At the time of fitting and fixing, the circumferential surfaces 21a and 22a in the recess are used as positioning surfaces in the direction orthogonal to the central axis l, and the step portions 21b and 22b are used as positioning surfaces in the direction parallel to the central axis l. The boss members 23 and 24 are replaced with the recesses 21 and
After fitting into 22, the protrusions 25 and 26 projecting from the joint portion of the boss member of the roller body 20 are moved by the thickness so as to project to the rear end surface of the joint portion by spin forming, as shown in FIG. 4c. The locking portions 27 and 28 are formed on the. According to this structure, it is possible to secure the coupling accuracy of the boss member with respect to the roller body in the axial direction and the direction orthogonal to the axis line, and also to secure the coupling strength with the roller body because the locking portion is formed by spin forming. You can

FIG. 5 shows a modified example of the method for manufacturing a crown roller according to the present invention. FIG. 5a is a diagrammatic sectional view of a pipe material to be formed, which is viewed from the side, and FIG. It is a diagrammatic sectional view taken along a plane including the central axis. In this example, three forming rollers 31 to 33 are arranged at equal angles along the circumferential direction of the pipe material 30 to be molded. As shown in FIG. 5b, these forming rollers are positive crown rollers having a length longer than the length of the tubular material 30 in the central axis direction. When these three forming rollers 31 to 33 are brought into pressure contact with the rotating pipe material 30, the forming rollers are driven to rotate. Then, when the three forming rollers are moved in a direction approaching the central axis of the pipe material while being pressed, the pipe material is plastically deformed in the radial direction along the outer shape of the forming roller, and the pipe material is equal to the crown amount of the forming roller. It becomes a type crown roller. Also in this example, since the pipe material 30 is rotated about its central axis, the roundness is corrected while the pipe material is plastically deformed, and a crown roller having a high roundness can be manufactured. Moreover, since the forming roller can be formed into a crown shape simply by moving the forming roller in the radial direction of the pipe material, the structure of the forming machine used can be simplified and the forming time can be further shortened.

The present invention is not limited to the above-described embodiments, and various modifications can be made. For example, in the above-described embodiment, an example in which the reverse crown roller is manufactured has been described, but it goes without saying that a regular crown roller can also be manufactured. Further, it is possible to manufacture a roller having a desired crown ratio, and when manufacturing a roller having a large crown ratio, not only the one-pass system but also the two-pass or three-pass system can be adopted.

Further, it is sufficient that the number of forming rollers is two or more.
It is also possible to use four or four forming rollers.
In this case, considering the action relationship of the force and the arrangement position of the forming rollers, it is preferable to use three forming rollers.

Further, in the above-described embodiment, the tube material is rotationally driven and the forming roller is driven to rotate. However, the tube material is rotatably supported via the clamp member, and the forming roller is connected to the motor to be rotationally driven to rotate the tube material. It is also possible to rotate the driven wheel. Furthermore, it is possible to rotate both the pipe material and the forming roller at an equal circumferential speed. In particular, when forming using a crown-shaped forming roller, it is necessary to apply a large pressing force due to line contact between the forming roller and the pipe material, so if the method of forcibly driving the forming roller is adopted, the pipe material will rotate smoothly. It is possible and especially preferable.

(Effects of the Invention) The effects of the present invention described above are summarized as follows.

(1) Since the crown shape is formed without cutting, a thin-walled pipe material can be used, and the manufacturing cost can be reduced. This is particularly effective when manufacturing a crown roller having a large crown amount. Further, since the pipe material made of a difficult-to-cut material which is inexpensive can be used, the manufacturing cost can be further reduced.

(2) Since the outer peripheral surface of the pipe material is regulated from at least three directions while the pipe material to be molded is rotated, a crown roller with high roundness can be manufactured. In particular, since it is possible to correct the center runout and roundness of the pipe material during the molding process, it is possible to manufacture a crown roller with high roundness and small center runout even when using a pipe material having a low roundness.

(3) Since the pipe material is plastically deformed in the inner peripheral direction without using a molding die (core), a crown roller having a desired crown shape and a desired crown ratio can be manufactured by a simple operation.

[Brief description of drawings]

1A and 1B are diagrams for explaining a method of manufacturing a crown roller according to the present invention, FIGS. 2A and 2B are schematic sectional views showing a plastically deformed state of a pipe material by a forming roller, and FIG. 3A. 4A and 4B are a plan view and a side view showing an example of a heat roll manufactured by using the crown roller manufactured according to the present invention, and FIGS. 4A to 4C are sectional views showing a modified example of the roller manufacturing method of the present invention. 5A and 5B are diagrams showing another modified example of the roller manufacturing method of the present invention. 1 ... Pipe material, 2a, 2b ... Clamping member 3, 4, 5 ... Forming roller

Claims (2)

[Claims] 1. When manufacturing a crown roller for a heat roll used in a heat roll fixing device in which the roller outer diameter continuously increases or decreases from a substantially central position of a central axis toward both ends, a forming process is performed. A clamp member for gripping both ends of the pipe material to be respectively formed, and a rotation axis line parallel to the center axis line, which are arranged at equal intervals along a circumferential direction of the center axis line in a plane orthogonal to the center axis line connecting the clamp members. At least three forming members that are rotatably supported about the center axis, move integrally in a direction parallel to the central axis line, and move in a direction orthogonal to the central axis line in equal distances from the central axis line. A spinning molding machine having rollers and pressing means for pressing these forming rollers against the pipe material is used, and both ends of the pipe material are clamped by the clamp members. Each of them is gripped, and at least one of the pipe material and the forming roller is rotationally driven, and the forming roller is moved in a direction parallel to the central axis of the pipe material while being pressed against the pipe material, and during the movement, the forming rollers are A method for manufacturing a crown roller, characterized in that the outer peripheral surface of the pipe material is formed into a crown shape while the inner peripheral surface of the pipe material is kept in a free state by moving the pipe material so that the distance from the central axis changes continuously. 2. When manufacturing a crown roller for a heat roll used in a heat roll fixing device in which the roller outer diameter continuously increases or decreases from the substantially central position of the central axis toward both ends from a pipe material, a molding process is performed. A clamp member for gripping both ends of the pipe material to be respectively formed, and a rotation axis line parallel to the center axis line, which are arranged at equal intervals along a circumferential direction of the center axis line in a plane orthogonal to the center axis line connecting the clamp members. Using a spinning molding machine having at least three forming rollers that are rotatably supported about a center axis and that move in a relationship in which the distances from the central axis are equal to each other, and pressing means that press these forming rollers against a pipe material. , The outer diameter of the forming roller is continuously increased or decreased from the substantially central position of its central axis toward both ends. A crown roller, which holds both ends of the pipe member by the clamp members, and rotationally drives at least one of the pipe member and the forming roller, and moves the forming roller in a direction approaching the central axis while pressing the pipe member against the pipe member. Then, the outer peripheral surface of the pipe material is formed into a crown shape while maintaining the inner peripheral surface of the pipe material in a free state, and a method for manufacturing a crown roller.