JP2002172449A - Method for machining rubber mounting face of damper pulley and lathe therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that in a method for shotblasting the peripheral face of a damper pulley in order to prevent slippage between a rubber and the inner or outer ring of the pulley from occurring, it is difficult to maintain the level or the like of formed unevenness within a definite range to continue the production of the damper pulley group stabilized in characteristics. SOLUTION: A lathe for machining the damper pulley has a chuck part 22a for chucking an inner ring W1 as a structure of the damper pulley and a main shaft 22 for rotating the chuck part 22a. Further, the lathe is provided with a machine tool fixing table 28 changeable between an attitude for positioning a cutting tool 30 at a location abutting on the outer peripheral face of the chucked inner ring W1 and the attitude for positioning a knurling tool 26 at the above location.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method of processing a rubber mounting surface of a damper pulley and a lathe therefor.

[0002]

2. Description of the Related Art A damper pulley is used to transmit rotation of a crankshaft or the like to accessories and the like. An example of the damper pulley will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of the damper pulley. A damper pulley W shown in FIG. 1 has an outer peripheral surface of an inner wheel (hub) W1 fixed to a rotating shaft S such as a crankshaft of an automobile, and an inner periphery of an outer wheel (pulley) W2 located radially outward of the inner ring W1. It is manufactured by assembling a rubber R between the surface and the surface. These inner ring W1 and outer ring W2 are generally cast. The rubber R transmits torque from a rotation shaft S such as a crankshaft, and reduces vibration due to internal friction of the rubber R. When circumferential slippage occurs between the outer peripheral surface of the inner race W1 and the rubber R or between the inner peripheral surface of the outer race W2 and the rubber R, transmission of rotation becomes impossible or vibration cannot be reduced. For this reason, it is necessary to prevent circumferential slippage from occurring between the outer peripheral surface of the inner race W1 and the rubber R or between the inner peripheral surface of the outer race W2 and the rubber R. The outer peripheral surface of the inner race W1 and the inner peripheral surface of the outer race W2 are usually finished using a lathe. For this reason, as shown in FIG. 2, cutting marks A are often formed on the outer peripheral surface of the inner ring W1 so as to extend in the circumferential direction. Also, the cutting marks A are formed on the inner peripheral surface of the outer ring W2 so as to extend in the circumferential direction.
Are often formed. The cutting marks A extending in the circumferential direction are formed between the outer peripheral surface of the inner ring W1 and the rubber R or the outer ring W
2 makes it easy to slide in the circumferential direction between the inner peripheral surface and the rubber R. Therefore, taking into account the cutting marks A extending in the circumferential direction,
Measures are needed to prevent slippage.

[0003] In order to prevent the occurrence of circumferential slippage,
Conventionally, shot blasting is performed on the outer peripheral surface of the inner ring W1 or the inner peripheral surface of the outer ring W2. FIG. 3 shows the shot blasting device 10. The apparatus 10 includes a shot grain tank 17, a shot grain projection nozzle 12 for projecting shot grains 13 (shown in an enlarged view in FIG. 4) contained in the tank 17, an inner wheel W1 or an outer wheel W2 (FIG. 3).
Is an example of processing the outer peripheral surface of the inner ring W1), and a turntable 16 for rotating the inner ring W1 around the axis K, and a surface other than the outer peripheral surface of the inner ring W1 (or a surface other than the inner peripheral surface of the outer ring W2).
A mask jig 15 for protecting the mask jig and an actuator 14 for moving the mask jig 15 are provided. In the shot blasting machine 10, while rotating the inner wheel W <b> 1 (or the outer wheel W <b> 2) with the rotary table 16, the shot particles 1 are shot from the shot particle projection nozzle 12.
By projecting No. 3, countless minute irregularities are provided on the outer peripheral surface of the inner ring W1 (or the inner peripheral surface of the outer ring W2). Cutting marks A extending in the circumferential direction due to the countless minute irregularities
Disappears and slippage between the outer peripheral surface of the inner race W1 and the rubber R or between the inner peripheral surface of the outer race W2 and the rubber R can be prevented.

[0004]

However, in the above-described shot blasting, since the size and shape of shot particles change with time, they are formed on the outer peripheral surface of the inner ring W1 or the inner peripheral surface of the outer ring W2. It is difficult to maintain the level of irregularities and fineness within a certain range. Further, since irregular irregularities are formed innumerably, it is also difficult to measure the level of irregularities, fineness, and the like.
For this reason, research has not been advanced on how much unevenness is formed to achieve a desired anti-slip effect, and what to manage and how to satisfy the condition. For this reason, it is difficult to continuously manufacture a damper pulley group having a stable torque transmission characteristic for a long period of time.
Further, a dedicated device 1 for shot blasting shown in FIG.
0 is required. In addition, since shot particles 13 broken small by collision are not suitable for use, the shot particles are sieved, and shot particles 13 having a certain size or less are discarded.
New shot grains 13 must be replenished. Further, the shot grains 13 are minute and sharp and pass through the projection nozzle 12 and the pipe at a high speed, so that damage to the projection nozzle 12 and the pipe is inevitable. Further, a mask jig 1 for protecting portions other than the outer peripheral surface of the inner ring W1 and the inner peripheral surface of the outer ring W2.
5 is inevitably damaged by long-term use. That is, shot blasting requires many consumables. As described above, in the method of processing the rubber mounting surface by shot blasting, it is difficult to manage a damper pulley group with difficult management and stable torque transmission characteristics for a long time, and the dedicated device 10 Required,
There is a problem that many consumables are required.

In view of the problem of shot blasting, the present inventor has proposed a better technique for preventing the occurrence of circumferential slip between the inner ring outer peripheral surface and the rubber or the outer ring inner peripheral surface and the rubber. We have been conducting research to achieve this, and as a result
A method using knurling has been reached. The inner ring and the outer ring of the damper pulley are manufactured by casting made of cast iron. The cast inner ring and the cast outer ring are hard and brittle,
It is widely known that it is not suitable for rolling processing such as low-lot processing. Actually, even if knurling is performed on the cast inner ring or the cast outer ring, only extremely minute irregularities can be formed. If the knurling is performed with such a force as to obtain large irregularities, the inner ring or the outer ring is broken. However, even in the case of extremely minute irregularities formed by knurling the cast inner ring or the cast outer ring, circumferential slippage between the inner ring outer peripheral surface and the rubber or the outer ring inner peripheral surface and the rubber may occur. It has been found by the inventor that it is sufficient to prevent occurrence. The present invention has been made based on such findings.

[0006]

Means for Solving the Problems, Actions and Effects The present invention relates to a method of assembling a damper pulley by inserting rubber between an outer peripheral surface of a wheel formed of inner cast iron and an inner peripheral surface of an outer ring formed of cast iron. The present invention relates to a method for processing an inner peripheral surface or an inner peripheral surface formed of outer cast iron. In this method, at least one of the outer peripheral surface of the inner race and the inner peripheral surface of the outer race is knurled to form irregularities extending in a direction non-parallel to the circumferential direction. Here, the direction of the “irregularities” refers to the direction in which the concave valleys of the concave portions extend, or the direction in which the peaks of the convex portions extend. The expression that the direction of the unevenness is “non-parallel” to the circumferential direction includes the case where the direction of the unevenness is “perpendicular” to the circumferential direction. Rubber is not limited to rubber in a narrow sense, but is a generic term for members having elasticity.

[0007] According to the method of the present invention, it is possible to reduce the occurrence of circumferential slip between the outer peripheral surface of the inner race and the rubber or the inner peripheral surface of the outer race and the rubber due to the extremely minute irregularities formed by knurling. Can be prevented. For this,
By performing knurling instead of shot blasting, a good damper pulley group can be efficiently produced. The method of the present invention is also useful when the inner ring outer peripheral surface or the outer ring inner peripheral surface is cut and formed with cutting marks extending in the circumferential direction, and the peripheral surface where the cutting marks remain is knurled. By doing so, it is possible to effectively prevent circumferential slippage from occurring between the outer peripheral surface formed of the inner race cast iron and the rubber or the inner peripheral surface of the outer race and the rubber.

According to the present invention, the following advantageous effects can be obtained as compared with a method of processing a rubber assembly surface by shot blasting. According to the method of the present invention, the use time of a knurl piece used for knurl processing, a pressing force,
By controlling the pressing time, it is possible to maintain the shape and the like of the irregularities formed on the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring within a certain range. As a result, a group of damper pulleys having stable torque transmission characteristics can be continuously produced. In addition, since the regular unevenness can be formed by knurling, the shape of the formed unevenness can be easily measured, and the timing of replacing the knurl piece can be accurately grasped. Alternatively, it is possible to quantitatively grasp the influence of the unevenness on the slip prevention effect. Furthermore, since knurling can be performed by general-purpose equipment such as a lathe, dedicated equipment such as a shot blasting apparatus is not required. Also, consumables are limited to knurl pieces used for knurling. For these reasons, the processing cost of the rubber assembly surface can be reduced.

In this method, it is preferable that the inner ring or the outer ring is cast. Cast inner rings and cast outer rings are usually not suitable for knurling because they are hard and brittle. In fact, the concavities and convexities formed by the method of the present invention are extremely minute, and are not normally suitable for the purpose of knurling. However, in the case of the rubber mounting surface of the damper pulley, extremely minute irregularities formed by knurling cause circumferential sliding between the inner ring outer peripheral surface and the rubber or the outer ring inner peripheral surface and the rubber. To effectively prevent

[0010] The present invention has also produced a lathe suitable for the above processing. This lathe has a chuck section for chucking an inner ring or an outer ring as a damper pulley structure, and a main shaft for rotating the chuck section. Further, a posture for positioning the cutting tool at a position in contact with the chucked inner ring outer peripheral surface or outer ring inner peripheral surface, and a posture for positioning the knurling tool at a position contacting the chucked inner ring outer peripheral surface or outer ring inner peripheral surface. And a tool holder that can be switched between the two.

According to the lathe of the present invention, the inner ring or the outer ring is chucked, the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring is first cut with a cutting tool, and then the knurling is performed without unchucking the inner ring or the outer ring. be able to. Therefore, special equipment as in the case of shot blasting becomes unnecessary, and the processing time can be further reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments embodying the present invention will be described with reference to the drawings. First, a lathe according to a first embodiment will be described with reference to FIG. FIG. 5 is a diagram showing a main part of the lathe according to the first embodiment. The lathe shown in FIG. 5 is roughly divided into a main shaft 22 and a chuck portion 22a.
And a tool fixing stand 28. The main shaft 22 is rotatable around the x-axis and is movable in the x-axis direction. A chuck portion 22a is attached to the main shaft 22. The chuck portion 22a fixes the work W1 that becomes the inner ring (specifically, a hub) of the damper pulley. When the work W1 is fixed to the main shaft 22 by the chuck portion 22a, the rotation center axis K of the work W1 coincides with the rotation center axis (x-axis) of the main shaft 22. The tool fixing base 28 is movable in the y-axis and z-axis directions. The cutting tool 30 and the flat knurling tool 26 can be attached to the tool fixing stand 28. The tool fixing base 28 is rotatable about a rotation axis 28a parallel to the z-axis, so that either the cutting tool 30 or the flat knurling tool 26 can be in a posture extending toward the workpiece W1. That is, the tool stand 28
It is possible to switch between a posture in which the cutting tool 30 extends toward the work W1 and a posture in which the flat knurling tool 26 extends toward the work W1. The cutting tool 30
A holding portion 30a fixed to the tool stand 28, and the holding portion 3
It has a byte portion 30b held by 0a.
The flat knurling tool 26 has a holding portion 26a fixed to the tool base 28, a pin 26c rotatably mounted on the holding portion 26a, and a flat knurl piece 26b mounted on the pin 26c. As shown in the side view of FIG. 6, the flat knurl piece 26b has a concave portion L and a convex portion M, and the unevenness extends in a direction perpendicular to the circumferential direction on the outer peripheral surface of the piece 26b. . Here, the direction of the unevenness is the direction in which the valley of the concave portion L forming the unevenness extends,
Alternatively, it means the direction in which the peak of the convex portion M extends. In addition,
The spindle 22 and the tool fixing table 28 are individually controlled by an NC device (not shown).

Next, the operation of the lathe according to the first embodiment shown in FIG. 5 will be described. First, the work W1 is attached to the main shaft 22 by chucking the work W1 with the chuck portion 22a of the main shaft 22. Then, the chuck portion 22 of the spindle 22
By rotating a around the rotation axis of the main shaft 22, the work W1 chucked by the chuck portion 22a is rotated around the axis K. In a state where the work W1 is rotated around the axis K, the tool fixing base 28 is moved to a position where the tip of the cutting tool 30b of the cutting tool 30 contacts the outer peripheral surface of the work W1.
To move. As a result, the outer peripheral surface of the work W1 is cut by the tip of the cutting portion 30b. During this time,
By appropriately changing the position of the main shaft 22 in the x-axis direction and the position of the tool fixing base 28 in the y-axis direction, the outer peripheral surface of the work W1 is cut into a predetermined shape. Thereafter, the tool fixing stand 28 is moved to a position away from the workpiece W1. Thus, the cutting of the work W1 is completed.

Next, the tool fixing table 28 is rotated counterclockwise by 90 degrees around the rotation axis 28a, so that the
As shown in (5), the posture of the flat knurling tool 26 is extended to the work W1. Thereafter, with the work W1 being rotated, the tool fixing base 28 is moved to a position where the flat knurl piece 26b of the flat knurl tool 26 contacts the outer peripheral surface of the work W1. The pressing force of the flat knurled piece 26b is adjusted by this position, and the level of unevenness formed on the outer peripheral surface of the work W1 is adjusted. The higher the pressing force, the deeper the irregularities are formed. As a result, the flat knurled piece 26b is driven by the rotation of the workpiece W1 and the pin 26 is rotated.
rotate around c. Thereby, knurling is performed on the outer peripheral surface of the work W1, and the unevenness of the flat knurl piece 26b is transferred to the outer peripheral surface of the work W1 as indicated by reference numeral B. Also, a flat knurled piece 26b is attached to the work W1.
By adjusting the pressing time, the shape of the unevenness formed on the outer peripheral surface of the work W1 is adjusted. Specifically, the longer the pressing time, the finer the irregularities are formed

By appropriately changing the position of the main shaft 22 in the x-axis direction and the position of the tool fixing base 28 in the y-axis direction, as shown in FIG. To form Thereafter, the tool fixing table 28 is retracted to a position away from the workpiece W1. Thereafter, the rotation of the work W1 is stopped by stopping the rotation of the main shaft 22. Thereafter, the work W1 is detached from the main shaft 22 by unchucking the work W1 from the chuck portion 22a of the main shaft 22. Thus, the flat knurling of the work W1 is completed. As described above, in addition to adjusting the pressing force and pressing time of the knurl pieces 26b, the pitch P of the unevenness of the knurl pieces 26b, the depth h of the convex portions M, and the inclination angle α of the convex portions M shown in FIG. By adjusting, it is possible to freely control the shape of the unevenness such as the unevenness level and the fineness.

The inner peripheral surface of the outer ring (ie, pulley) can be knurled in substantially the same manner. First, the inner peripheral surface of the outer ring rotated by the main shaft is cut and then knurled. Also at this time, the cutting and the knurling can be continued without unchucking the outer ring. After knurling is performed on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring to form fine irregularities, for example,
Rubber is assembled between the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring by a rubber press-fitting device as described in Japanese Patent No. 7031.
Thereby, the damper pulley is completed.

In the above, unevenness perpendicular to the circumferential direction is formed by knurling. However, the direction of the unevenness need not be a right angle, but may be any direction that is non-parallel to the circumferential direction (intersecting direction). Also, it is not necessary to knurl both the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, and by performing knurling on the peripheral surface that starts sliding with rubber first, the torque value at which sliding starts can be improved.

Next, a lathe according to a second embodiment will be described with reference to FIG. FIG. 9 is a perspective view showing the inner race in a state where the surface processing is performed by the lathe according to the second embodiment.
Since the lathe according to the second embodiment differs from the lathe according to the first embodiment only in the portion of the knurling tool 27, illustration of a spindle, a tool fixing stand, and the like is omitted in FIG. As shown in FIG. 9, in the lathe according to the second embodiment, two knurl pieces 27b and 27c are provided in the holding portion 27a of the knurl tool 27. This knurl piece 27b and 2
7c has irregularities in a direction obliquely inclined with respect to the circumferential direction, and the knurled pieces 27b and 27c have mutually opposite inclination directions. As in the case of the first embodiment,
With the work W1 chucked and rotated, the knurled pieces 27b and 27c of the knurling tool 27 are moved to the work W1.
When the workpiece W1 is advanced to a position where it comes into contact with the outer peripheral surface of
Is subjected to knurling on the outer peripheral surface. As a result, the uneven shape of the two knurl pieces 27b and 27c is changed to the work W1.
Is transferred, and irregularities in the form of a stitch are formed as shown by reference numeral C. As in the case of the first embodiment, if the position of the main spindle (not shown) and the position of the tool fixing table are appropriately changed, FIG.
As shown in (1), fine pit-like irregularities are formed on the entire outer peripheral surface of the work W1.

Although the lathe according to the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications and improvements are made based on the knowledge of those skilled in the art. Can be implemented. For example, in this embodiment, a cutting tool 30 and a knurling tool 26 are previously mounted on a tool fixing stand 28, and both tools are connected to a rotating shaft 28a.
Although an example in which switching is performed has been described, the present invention is not limited to this. For example, a tool hand for various tool chucks is provided on the tool fixing base 28, and the cutting tool 30 is chucked by the tool hand when cutting is performed, and the knurl tool 26 is chucked by the tool hand when performing knurling. Is also good.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a damper pulley.

FIG. 2 is a diagram showing cutting marks on the outer peripheral surface of an inner ring.

FIG. 3 is a view showing a shot blasting apparatus.

FIG. 4 is an enlarged view of FIG. 3;

FIG. 5 is a diagram (1) showing a main part of the lathe according to the first embodiment.

FIG. 6 is a side view of the flat knurling tool of the lathe according to the first embodiment.

FIG. 7 is a diagram (2) showing a main part of the lathe according to the first embodiment.

FIG. 8 is a diagram showing an outer peripheral surface of an inner ring subjected to knurling by the lathe according to the first embodiment.

FIG. 9 is a perspective view showing the inner race in a state where knurling is performed by the lathe according to the second embodiment.

FIG. 10 is a diagram showing an outer peripheral surface of an inner ring subjected to knurling by a lathe according to a second embodiment.

[Explanation of symbols]

 W: Work (damper pulley) W1: Inner ring W2: Outer ring R: Rubber S: Crankshaft 22: Main shaft 22a: Chuck portion 26: Flat knurling tool 26b: Flat knurling piece 27: Aya knurling tool 27b, c: Aya knurling Piece 28: Tool fixing stand 28a: Rotating axis 30: Cutting tool

Claims (3)

[Claims] 1. A method for processing an inner ring outer peripheral surface or an outer ring inner peripheral surface prior to assembling a damper pulley by inserting rubber between an inner ring outer peripheral surface and an outer ring inner peripheral surface formed of cast iron. Knurling at least one of the outer peripheral surface of the inner race and the inner peripheral surface of the outer race to form irregularities extending in a non-parallel direction with respect to the circumferential direction; . 2. The method according to claim 1, wherein the inner ring or the outer ring is cast. 3. A chuck chuck portion formed of an inner ring cast iron or an outer ring as a damper pulley constituting a damper pulley, and a main spindle for rotating the chuck portion.
The attitude of positioning the cutting tool at a position in contact with the chucked inner ring outer peripheral surface or the outer ring inner peripheral surface work surface, and the position of positioning the knurling tool at a position abutting on the inner ring outer peripheral surface or outer ring inner peripheral surface work surface. A lathe for machining a damper pulley with a tool holder that can be switched between.