JPH04344843A - Manufacture of steel sheet with groove - Google Patents

Abstract

PURPOSE:To prevent the breakage of steel sheet on the halfway of manufacturing by pressing a steel sheet therebetween with rolls having projections on the outer peripheral part, pulling the steel sheet from a front part to manufacture the steel sheet having groove. CONSTITUTION:By pressing the steel sheet 2 therebetween with first rolling rolls 1 having projections to an axial direction and second rolling rolls 3 having projections to a circumferential direction, to execute cold rolling. The steel sheet 2 passing through the second rolling rolls 3 is taken up with a driving coiler 4. The coiler 4 not only takes up the steel sheet 2, but also pulls the steel sheet 2 with its tension, and the rolling rolls 1, 3 are rotated to execute rolling for forming the groove. After completing the rolling process for forming the groove, the steel sheet 2 passes between a pair of flat rolls having flat outer peripheral face to execute a finish rolling. The loads of rolling rolls 1, 2 are reduced and the number of times for stopping the equipment due to breakage during manufacturing can be drastically reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a grooved steel plate used for a grooved clutch plate, etc., which is a part of an automobile differential.

0002

2. Description of the Related Art Grooved steel plates are used as clutch plates for clutches that transmit the driving force of an engine to wheels of automobiles. Since the clutch plate is used in a harsh friction environment, it is necessary to pay attention to surface treatment and lubrication in order to prevent seizure and wear. When a steel plate is used with grooves, lubricating oil is retained inside the grooves and has the effect of preventing seizure and wear, so grooved steel plates are used in some clutch plates.

[0003] A differential limiting device is an example of a device in which a grooved steel plate is used. This device is a device that increases the transmitted torque of the other wheel that does not spin when one of the left and right wheels spins in muddy or icy roads and the transmitted torque decreases, allowing smooth driving. It is.

[0004] In a normal differential gear, the same torque is always transmitted to the left and right wheels. Therefore, if one wheel spins in mud or the like and the transmitted torque decreases, the transmitted torque of the other wheel also decreases, making it impossible to escape. Differential limiting devices are available to solve these problems of conventional differential devices.

[0005] Grooved steel plates used in differential limiting devices include:
There are two or more horizontal groove groups on the surface that intersect in a lattice pattern with vertical groove groups.
They are formed at a pitch of about 8 mm. Plate thickness is 1-3m
m, and the groove dimensions are 0.2 to 0.5 mm deep.
, the width is about 0.3 to 1.0 mm.

[0006] In manufacturing a grooved steel plate having the above characteristics, grooves have conventionally been formed by corroding the steel plate by etching. In other words, after forming a film by masking the parts of the steel plate excluding the parts where the grooves will be formed, the steel plate is immersed in an etching solution to corrode only the parts that are not coated, and then the film is removed to form the grooves. It was made of steel plate.

However, with the etching method, it is difficult to adjust the shape of the groove as desired, and corrosion tends to spread laterally toward the deeper part of the groove, resulting in a shape that becomes narrower toward the surface. Although such a shape is preferable in terms of retaining lubricating oil, it is difficult for the retained lubricating oil to come out from the surface, and the effect of improving lubricity, which is the original objective, is reduced.

Furthermore, grooves formed by etching tend to have protrusions on the surface side, and if a grooved steel plate having protrusions is attached to a differential limiting device and used, this will cause noise generation when the vehicle is operated.

[0009]Furthermore, the size of the steel plate is limited due to the size of the tank in which the etching solution is immersed, and since oil cannot be applied during the process, rust is likely to occur.

[0010] In order to eliminate the drawbacks of the method for forming grooves by etching, the applicant has developed and already proposed a method for producing a grooved steel plate by cold rolling. (Unexamined Japanese Patent Publication No. 63-43703, No. 63-49303)

0
[011] In this method, rolling rolls provided with protrusions for forming the desired groove shape are prepared, the steel plate is pressed in the thickness direction to form lattice-shaped grooves, and then finished with smooth rolling rolls. The grooves are formed by plastic working, such as rolling.

[0012] Since this method is manufactured by plastic working, the groove shape is determined by the shape of the protrusions on the surface of the rolling roll to be prepared, and fine adjustment of the shape is also easily possible by changing the shape of the protrusions. This method does not have the disadvantage that the deep grooves spread laterally, which is the case with etching methods. Moreover, since it can be manufactured continuously, productivity is good, and since it is possible to apply oil, rust can be completely eliminated.

However, as the inventors of the present invention accumulated experience in manufacturing by this method, it became clear that there were some drawbacks. In other words, the protrusions provided on the surface of the rolling roll to form grooves must be extremely thin due to the dimensions of the grooves to be formed, and as a result, due to the pressure applied to the roll during rolling and the plastic flow of the material, The projections may break and a new roll must be manufactured each time. The rolling rolls used in this method have a more complicated shape than normal rolls, and therefore are more expensive to manufacture, and there has been a strong desire for immediate countermeasures.

[0014] Furthermore, when a roll breaks, the equipment is completely stopped and new adjustments to the equipment such as roll replacement are required, resulting in a significant delay in the production schedule.

[0015]

[Problems to be Solved by the Invention] The present invention solves the above-mentioned problems, and provides a grooved steel plate that prevents early breakage of the protrusions formed on the rolling roll and ensures stable production when producing a grooved steel plate by rolling. The purpose is to provide a method for manufacturing steel plates.

[0016]

[Means for Solving the Problems] The present inventor has conducted intensive research on a rolling method that can prevent breakage of the roll protrusion, and has discovered the following manufacturing method.

There are two ways of thinking about how to prevent the protrusion from breaking. One is to change the shape of the protrusions to make them less likely to break, and the other is to reduce the load on the protrusions on the roll surface when forming grooves, so that the force applied to the protrusions can be reduced by increasing the strength of the protrusions. The goal is to keep it lower.

When considering the former method, the shape of the groove is set to an appropriate shape to improve lubricity. If the groove is made wider, the groove formed will be wider on the surface side, and the original purpose of retaining lubricating oil will be lost. Therefore, the shape of the protrusion can only be changed within a very limited range of conditions, and the above problem has not been solved.

[0019] Therefore, the latter method was further studied. That is, an attempt was made to manufacture a grooved steel plate by applying forward tension using a winding device after rolling to reduce the load on the protrusions on the roll surface. As a result of repeating prototype tests by varying the tension applied to the steel plate at several levels, we found that the greater the front tension, the greater the effect, especially when the tension was maximized and rolling was performed without applying driving force to the rolls. It was found that the effect was large.

The method for manufacturing a grooved steel plate according to the present invention, which was completed based on the above knowledge, is to compress the steel plate in the thickness direction using rolls having a large number of successive protrusions at a predetermined pitch on the outer periphery. When manufacturing a steel plate having lattice-like grooves, the grooves are formed on the surface of the steel plate by forward tension. However, driving force to the rolls is not required at all, and there may be cases where it is better to add an auxiliary load for reasons such as equipment availability.

[0021] In the groove forming rolling process, there are two methods: a method of forming vertical groove groups and a horizontal groove group of the grooved steel plate using separate rolling rolls, and a method of forming them using a single rolling roll.

In the former case, the first roll has a protrusion that is parallel to the axial direction of the roll or is formed of a protrusion that extends parallel to the axial direction at a predetermined angle, and the circumference of the roll. Rolling is performed using a second roll having a protrusion extending in the direction or a protrusion extending parallel to the circumferential direction of the roll and inclined at a predetermined angle.

In the latter case, rolling is performed using rolls having lattice-like protrusions on the outer periphery. Several types of rolls can be used as specific shapes of the lattice-like protrusions.

One of the rolling rolls includes a first group of protrusions extending at an angle of 45 degrees with respect to the axis of the roll, and a second group of protrusions extending in a direction substantially perpendicular to the first group of protrusions. Rolls with protrusions can be used.

In some cases, with respect to the axis of the roll,
It is also possible to use a rolling roll consisting of a first group of protrusions extending obliquely at an angle smaller or greater than 45 degrees, and a second group of protrusions intersecting the first group at a substantially right angle.

It is also possible to use a rolling roll comprising a first group of protrusions extending substantially parallel to the axis of the roll and a second group of protrusions intersecting orthogonally to the first group of protrusions.

The former method requires rolling twice to form the grooves, while the latter method requires only one rolling, but the shape of the rolling rolls in the latter is more complex and the cost of manufacturing the rolls is lower. It gets expensive. Therefore, it is desirable to take the total cost into consideration and select an optimal roll shape.

In the manufacturing method of the present invention, it is necessary to apply forward tension to the steel plate, but at the start of rolling, there is a portion at the tip of the steel plate where tension cannot be applied. Therefore, it is desirable to install the rolling mill and the tension loading device such as the winding device as close as possible.

[0029] As the rolling roll, forged steel rolls, chilled rolls, sand rolls, grain rolls, hollow rolls, composite rolls, cast steel rolls, etc. can be used, but in consideration of their wear resistance, forged steel rolls are preferred. preferable. Preferably, the protrusion is heat-treated to make it tough and hard.

[0030]

[Example] As shown in Fig. 1, in the groove forming rolling process, a pair of first rolling parts are formed in which a large number of protrusions 10 extending parallel to the axial direction 11 are successively arranged in the circumferential direction at a pitch of 4 mm. A steel plate 2 (steel type SK5) having a width of 90 mm and a thickness of 1.6 mm is pressed in the thickness direction by the rolls 1 and cold rolled. As a result, lateral groove groups 20 perpendicular to the rolling direction are formed on both sides of the steel plate 2. The first rolling roll 1 has a roll diameter of 195 mm, a roll body length of 140 mm, and a protrusion on the surface having a shape as shown in FIG. 3, and a width of 0.6 mm.
The height is 0.4 mm.

The steel plate 2 on which the lateral grooves 20 have been formed is rolled in the thickness direction by a pair of second rolling rolls 3 each having a large number of protrusions 30 extending in the circumferential direction arranged in succession at a pitch of 3.5 mm. It is pressed and cold rolled. In this way, steel plate 2
A group of vertical grooves 21 is formed on both sides of the groove, and together with the group of horizontal grooves 20, a lattice-like groove is completed. Note that the second rolling roll 3 has the same dimensions as the first rolling roll except for the direction of the protrusions on the surface.

As shown in FIG. 2, the steel plate 2 that has passed through the second rolling roll is wound up by a drive winding device 4. As shown in FIG. The winding device not only winds up the steel plate, but also applies forward tension to the steel plate. By pulling the steel plate with this tension, the rolling rolls 1 and 3 are rotated to perform groove forming rolling. conduct.

After completing the groove forming rolling process as described above, the steel plate 2 is rolled using a pair of smooth rolls each having a smooth outer peripheral surface.
Finish rolling is performed by pinching. By performing finish rolling in this manner, the flatness of the surface of the steel plate 2 is greatly improved.

[0034] Based on the method explained above, the grooved steel plate was
ton was manufactured, and the breakage status of the protrusion-equipped rolling rolls 1 and 3 was investigated. As a result, although slight changes in the groove shape due to wear of the protrusions were observed, there was no breakage during manufacturing.

[0035] Further, the problems caused by defects in the groove shape that occur when manufacturing by etching processing are completely eliminated, as in the conventionally proposed manufacturing method of driving rolling rolls, and the present invention can be applied to the differential limiting device. Even when a grooved steel plate was installed, no problem noise was generated, and a good oil film was formed by retaining the lubricating oil, so the service life was greatly improved.

[0036]

Effects of the Invention: The method for producing a grooved steel plate of the present invention does not drive a rolling roll having protrusions, but rather pulls the steel plate, so the load on the rolling roll is reduced and there is no risk of breakage during production. The number of equipment stoppages has been significantly reduced, making it possible to perform stable manufacturing. In addition, the grooved steel sheet manufactured according to the present invention can solve the problem of groove shape, which is a problem with the etching treatment method, so it can have an excellent lifespan when used as a clutch plate for a differential limiting device, etc. It is possible to prevent the occurrence of noise.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view of a groove rolling process in an embodiment of the present invention.

FIG. 2 is a schematic diagram of an embodiment of the manufacturing method of the present invention.

FIG. 3 is an enlarged cross-sectional view of a protrusion on the surface of the first rolling roll.

[Explanation of symbols]

1 First rolling roll 2 Steel plate 3 Second rolling roll 4 Drive winding device 5 Pinch roll 10 Projection (first rolling roll) 20 Transverse groove group 21 Vertical groove group 30 Projection (second rolling roll)

Claims (1)

[Claims] 1. When manufacturing a steel plate having a lattice-like groove on its surface by pressing a steel plate in the thickness direction with a roll having a plurality of successive protrusions at a predetermined pitch on the outer periphery, the grooves are compressed by forward tension. 1. A method for producing a grooved steel plate, which comprises forming a grooved steel plate on the surface of the steel plate.