JP2002326123A - Gear honing stick - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear honing stick that can ensure high efficiency and wear resistance. SOLUTION: Since at least an internal tooth portion 14 involved in polishing in the gear honing stick 10 includes a lumped abrasive grain G1, in honing, in comparison with that of a conventional gear honing stick using a general abrasive grain, a reduced elastic escape in cutting due to a large diameter of the lumped abrasive grain G1 can increase a depth of cut, and pores formed in the lumped abrasive grain G1 itself function as chip pockets to sustain sharpness, with the result that high polishing efficiency can be obtained. Since the lumped abrasive grain G1 is sufficiently larger in diameter than a filler G2 or than abrasive grains included in the lumped abrasive grain G1 and has a complex rugged shape, sufficient gripping force by a resin bond PB can be ensured, with the result that high wear resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a honing wheel for a gear for polishing a tooth surface of a gear.

[0002]

2. Description of the Related Art For example, a gear used for a transmission of an automobile is subjected to a honing process after a quenching process in order to reduce gear noise, thereby removing quenching distortion and improving the accuracy of tooth surfaces. Have been. In such processing, for example, general abrasive grains such as alumina oxide and silicon carbide were bonded by a resin binder made of a thermosetting resin such as phenol and epoxy, and high-precision inner peripheral teeth were formed on the inner peripheral surface. An internal tooth type grindstone is used. For example, a honing wheel for gears provided with a plurality of inner peripheral teeth meshing with outer peripheral teeth of a gear (work) is such. Prior to such honing, the internal tooth grindstone for honing is dressed using a dress gear in which diamond abrasive grains are fixed to the surface by electrodeposition or the like, and then the internal teeth are engaged with the gear-shaped work, By rotating the work around the axis while reciprocating in the axial direction, the tooth surface of the work is polished.

[0003]

In the dressing process of the honing grindstone for gears, a resinoid grindstone is used in which a resin binder is used to bind abrasive grains. Due to elasticity, sufficient sharpness was not always obtained, and polishing efficiency was sometimes not obtained. Further, the gripping force of the abrasive grains by the resin binder is not always sufficient, and in some cases, sufficient wear resistance may not be obtained due to the abrasive grains falling off.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a honing wheel for gears, which has high efficiency and abrasion resistance.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the gist of the present invention is to provide a honing wheel for a gear having a plurality of teeth for meshing with the gear in order to grind the tooth surface of the gear. In this case, the plurality of abrasive grains are bonded by an inorganic binder, and the massive abrasive grains having a diameter larger than that of the abrasive grains are bonded by a resin binder.

[0006]

According to the present invention, since a plurality of abrasive grains are combined by the inorganic binder and the massive abrasive grains having a larger diameter than the abrasive grains are combined by the resin binder, the massive abrasive grains are combined. Since the grains have pores structurally and their size is large, they are less likely to be returned by elasticity at the time of cutting, so that sufficient sharpness can be obtained and polishing efficiency can be obtained. In addition, the above-mentioned massive abrasive grains have a large diameter because they are a combined body of a plurality of abrasive grains, and the surface has a complicated uneven shape, so that the gripping force by the resin binder is large, so that the abrasive grains fall off. And sufficient abrasion resistance can be obtained.

[0007]

[Another embodiment of the invention] Here, preferably, in the honing grindstone for the gear, the resin binder are those containing a filler, the strength of the abrasive agglomerates of strength S _G and the resin binder S The intensity ratio with _PB (S _G / S _PB ) is 1.5 or less. By doing so, the surface roughness of a high-quality work with few scratches can be obtained, and the wear resistance of an expensive gear-shaped dressing tool (dress gear) having a diamond electrodeposited on the surface can be enhanced.

Preferably, the strength S _{G of the} massive abrasive is
And the intensity ratio between the intensity S _B of the resin binder (S _G / S _PB)
Is less than 1.0. That is, the intensity S _G of the abrasive agglomerates is lower than the strength S _B of the resin binder. By doing so, the surface roughness of the work can be obtained with less scratches, and the durability of an expensive gear-shaped dressing tool (dress gear) having a diamond electrodeposited on the surface can be further enhanced.

Preferably, in the honing wheel for a gear, the resin binder is 15 to 30% by weight, the massive abrasive is 5 to 50% by weight, and the filler is 40 to 75% by weight.
% By weight. In this way, a high polishing efficiency and a long life can be obtained. When the amount of the above-mentioned massive abrasive grains is less than 5% by weight, the effect of improving the polishing efficiency becomes difficult to be obtained, and when the amount exceeds 50% by weight, the effect is saturated.

[0010]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view showing an entire honing wheel 10 for a gear according to an embodiment of the present invention. The gear honing grindstone 10 is an internal tooth type honing grindstone having inner peripheral teeth for polishing outer peripheral teeth of a material to be polished (work material) 18 such as a helical gear and a pinion, and has a ring shape as a whole. For example, outer diameter is about φ300mm, inner diameter is φ25
It is formed to have dimensions of about 0 mm and a width (length in the axial direction) of about 40 mm. The honing wheel 10 for this gear is
For example, as shown in FIG. 2, an annular main body 12 and a plurality of inner peripheral teeth 14 projecting radially from a plurality of circumferential locations on the inner peripheral surface of the main body 12 are integrally provided. I have. The inner peripheral tooth portion 14 is, for example, a plurality of helical inner peripheral teeth inclined at a predetermined angle with respect to the axial direction. The inner peripheral tooth portion 14 has, for example, m (module) of 2.0, P
(Pressure angle) is 17.5 and Z (number of teeth) is 120. The inner diameter of the internal tooth type honing grindstone 10 is the diameter of a cylindrical surface passing through the tip of the internal peripheral tooth portion 14.

The main body portion 12 and the inner peripheral tooth portion 14 are composed of, for example, a massive abrasive grain G1 of about # 8 and a filler G2 of about # 100 made of abrasive grains such as fused alumina white alundum (WA). One bonded with a thermosetting resin binder PB such as an epoxy resin or a phenol resin so as to have a bonding degree R and a structure 7 (for example, WA / X100)
R 7 Y), for example, having an elastic modulus of 10 to 15 GP.
a and a coefficient of thermal expansion of about 25 × 10 ⁻⁶ / ° C.

The massive abrasive grains G1 have a sufficiently larger diameter than superabrasive grains such as CBN or general abrasive grains such as alundum and silicon carbide bonded by vitrified bond which is a vitreous inorganic binder. Particles. The massive abrasive grains G1 are obtained by, for example, grinding a vitrified grindstone which has been subjected to a normal vitrified grinding wheel manufacturing process using the above-described abrasive grains and a vitrified bond into a granular form, or a press-formed and unfired raw grindstone into a granular form. Since it is sintered afterwards, the abrasive grains and the vitrified bond are granulated to a predetermined particle size from the beginning using a binder, and then sintered, the abrasive grains and the vitrified bond are bonded by the molten vitrified bond and the Has a configuration similar to that of a normal vitrified grindstone in which a relatively large space is formed, and its outer shape is formed into a complex uneven shape by a plurality of abrasive grains.

The massive abrasive grains G1 are, for example, 20-60M.
Provided with a strength S _G and 15~40GPa modulus of Pa, the resin binder PB containing filler G2, for example the intensity of 70～150MPa S _PB and 10~15GP
a, and the strength S _{G of the} massive abrasive grains G1
The ratio of the resin binder PB containing the filler G2 to the strength S _PB (S _G / S _PB ) is 1.5 or less, more preferably less than 1.0. The mixing ratio and the manufacturing conditions are set. This strength is, for example, as shown in FIG.
A test piece of mm × thickness (t) of 10 mm was prepared, and, for example, as shown in FIG. MPa) is used.

The honing wheel 10 for a gear is manufactured, for example, according to a well-known manufacturing process of a resinoid wheel shown in FIG. First, in the raw material adjustment step, a grinding stone raw material is prepared and weighed so as to have a predetermined mixing ratio. At this stage, 5 to 50% by weight, preferably 5
Up to 35% by weight of the massive abrasive grains G1, 40 to 75% by weight of the filler G2, and 15 to 30% by weight of the resin binder PB are prepared. Next, after the prepared materials are kneaded in a kneading step, in a hot press step, the material is filled into a mold, and is pressed and heated for a predetermined time,
Molded and bonded. Next, in the aging step, aging is performed for a predetermined time at a predetermined temperature to stabilize the quality, and in the finishing step, the outer peripheral surface is finished by dressing or dressing.

As shown in FIGS. 6 (a) and 6 (b), for example, as shown in FIGS. 6 (a) and 6 (b), the gear honing grindstone 10 constructed as described above has a predetermined shape accuracy of a workpiece 18 which is a quenched work. This is used for polishing, that is, honing, performed to obtain a steel sheet. In FIG. 6 (a), a material 18 to be polished, such as a helical gear, is attached to a rotating shaft 20 supported at both ends (not shown) so as to be relatively unrotatable in the axial direction and the circumferential direction. When the rotating shaft 20 is driven by a drive mechanism (not shown), the helical gear 18 is rotated about its axis and reciprocated in the direction of the axis. On the other hand, the gear honing grindstone 10 is configured such that the inner peripheral teeth 14 mesh with the outer peripheral teeth of the work material 18 as shown in FIG.
As shown in FIG. 6A, the axis is inclined at a predetermined angle with respect to the direction of the axis of the rotating shaft 20, and as shown in FIG. They are arranged at a predetermined distance. Then, by being rotatably mounted on a holder or the like (not shown) on the outer peripheral surface around the axis thereof, the member 18 is rotated while the meshed state is maintained with the rotation of the workpiece 18. Thereby, the material to be polished 18
The shape of the inner peripheral tooth portion 14 of the honing grindstone 10 for the gear is transferred to the, thereby improving the shape accuracy.

Since at least the inner peripheral teeth portion 14 of the gear honing wheel 10 involved in polishing contains the massive abrasive grains G1, the above-mentioned honing process uses a conventional gear honing wheel using general abrasive grains. In comparison, since the massive abrasive G1 has a large diameter and the amount of elastic relief at the time of cutting is reduced, the amount of cut can be increased, and further, pores are formed in the massive abrasive G1 itself, which is a chip pocket. , A continuous sharpness is obtained and a high polishing efficiency is obtained. In addition, the above-mentioned massive abrasive grains G1
Is larger in diameter than the filler G2 or the abrasive grains contained in the massive abrasive grains G1, and has a complicated uneven shape. Therefore, a sufficient gripping force by the resin binder PB is obtained, A high abrasion resistance can be obtained by reducing the falling off, and a high quality polished surface can be obtained without deteriorating the surface roughness due to the scratches caused by the abrasive grains falling off.

In the honing wheel 10 for a gear as described above, when the inner peripheral teeth 14 of the main body 12 are worn, the dressing and the shape are periodically performed using a dresser in order to maintain the polishing accuracy. It needs to be fixed,
The dressing operation is performed, for example, by attaching a dress gear (dresser) in which diamond abrasive grains are electrodeposited on a surface of a similar shape in place of the material to be polished 18 in FIGS. It is common to be done. At this time, the dress gear is operated so as to press the inner peripheral surface of the internal tooth type honing grindstone 10 in order to give an appropriate cutting amount, and in the internal peripheral surface and the tooth groove 16 of the internal peripheral tooth portion 14, A relatively large stress acts on the outer peripheral side.

In the above-mentioned dressing step, the dress gear which has the same outer shape as that of the helical gear 18 and whose surface is coated with diamond abrasive grains and which is most susceptible to damage is the tip of the dress gear which is brought into sliding contact with it. Even if a large processing load, that is, stress or frictional heat is concentrated on the tooth tip, the difference in hardness between the massive abrasive grains G1 and the resin binder PB containing the filler G2, that is, the strength ratio (S _G / S _PB) ) Is 1.5
Hereinafter, the filler G2 is preferably less than 1.0 and relatively
The presence of the soft massive abrasive grains G1 having a low strength with respect to the resin binder PB containing, preferably prevents the diamond abrasive grains at the tooth tips from falling off or peeling off, and reduces the scratches and reduces the polished surface roughness of the workpiece 18. As a result, the durability of an expensive gear-shaped dressing tool (dress gear) having a surface on which diamond is electrodeposited is enhanced.

Further, according to this embodiment, in the honing wheel 10 for a gear, the resin binder PB is 15 to 30% by weight, the massive abrasive G1 is 5 to 35% by weight, and the filler G2 is 40% by weight.
Since it is contained in an amount of up to 75% by weight, a high polishing efficiency and a long life can be obtained. When the amount of the above-mentioned massive abrasive grains is less than 5% by weight, the effect of improving the polishing efficiency becomes difficult to be obtained, and when the amount exceeds 35% by weight, the effect is saturated.

Next, a description will be given of an experimental example conducted by the present inventors on a sample 1 using massive abrasive grains and a sample 2 not using massive abrasive grains under the experimental methods and experimental conditions described below.
According to the experimental results, in the case of the sample 2 not using the massive abrasive grains, 5
While the allowance was about 0 μm, the allowance of about 100 μm was possible in Sample 1 using the massive abrasive grains. Further, the dress interval (the number of pieces that can be polished per dressing) was 15 pieces / D in the sample 2, whereas 30 pieces / D was possible in the sample 1. That is, the sample 1 using the massive abrasive grains to which the present invention is applied, as compared with the sample 2 not using the massive abrasive grains, can obtain a high polishing efficiency with good sharpness and a long dress interval, and has a long dress interval. This indicates that the durability life of the dresser has been obtained.

(Sample 1) Indication of composition of grinding stone: WA / X 100 R 7 Y (WA100I was crushed to prepare massive abrasive grains, and 20% of massive abrasive grains equivalent to # 8 and white alundum equivalent to # 100) 80% of the mixed abrasive grains and the epoxy resin binder are in a ratio of Vg = 49 and Vb = 47, that is, 23.2% by weight of massive abrasive grains (# 8) and 57.5% of WA abrasive grains.
1% by weight and 19.3% by weight of an epoxy resin binder are mixed and combined to give a bonding degree R and a concentration degree of 7.・ Design specific gravity = 2.37

(Sample 2) Composition display of grindstone: WA80 R 7 Y (# 80 equivalent abrasive grains composed of white alundum (WA) and epoxy resin binder, Vg = 49, Vb = 47
, That is, WA abrasive grains are mixed and bonded at a ratio of 80.9% by weight and an epoxy resin binder at a ratio of 19.1% by weight, thereby obtaining a degree of bonding R and a degree of concentration of 7.・ Design specific gravity = 2.41

(Experimental Method) In order to improve the reproducibility and easiness of the experiment, in this experiment, a sample having a shape different from that of the honing grindstone 10 and a work having a shape different from the workpiece 18 were prepared and used. I have. In other words, a plate-shaped (board) -shaped grindstone is fixed to a base such as an iron plate as a sample, and a disk-shaped work, which is regarded as a work, is rotated around an axis parallel to the upper surface of the plate-shaped grindstone from above. A certain amount of incision was made in the above, and the processing amount (cut allowance) for the outer peripheral surface of the disk-shaped work was measured. When the processing amount falls below 30% of the initial value due to a decrease in the sharpness of the sample flat grinding wheel, the processing is stopped and the upper surface of the flat grinding wheel (working surface)
Was dressed. An appropriate dressing interval was set for each sample.

(Experimental conditions)-Plate-shaped grindstone dimensions: length 150 mm x width 130 mm x thickness 20 mm-disk-shaped work dimensions: outer diameter 100 mmφ x thickness 12 mm x inner diameter 76.2 mmφ-work material: SCM420-dresser: the above work・ Electrodeposited with # 80 diamond ・ Work rotation speed: 750 rpm ・ Grinding fluid: water-insoluble ・ Cut: 120 μm

While the embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be applied to other embodiments.

For example, in the above-described embodiment, the gear honing grindstone 10 has the inner peripheral tooth portion 14 and
Although the outer peripheral teeth of No. 8 are honed, the outer peripheral teeth for honing the inner peripheral teeth of the workpiece may be provided.

In the honing wheel 10 for a gear of the above-described embodiment, the filler G2 made of white alundum (WA) is mixed in the resin binder PB. And the filler G2 does not necessarily have to be included.

Further, in the honing wheel 10 for gears of the above-described embodiment, as shown in FIG. 2, the massive abrasive grains G1 are entirely mixed, but only on the surface layer of the inner peripheral surface involved in polishing. It may be locally mixed.

In the honing wheel 10 for a gear according to the above-described embodiment, the massive abrasive grains G1 are obtained by combining WA abrasive grains with a vitrified binder, but CBN.
Abrasive grains, diamond abrasive grains, silicon carbide abrasive grains, and the like may be combined with a vitrified binder.
In short, it is only necessary for the massive abrasive grains G1 to have an intensity ratio of 1.5 or less, preferably less than 1.0, to the intensity of the other portions.

Although not specifically exemplified, the present invention can be variously modified without departing from the spirit thereof.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an entire honing wheel for a gear according to an embodiment of the present invention.

FIG. 2 is an enlarged view for explaining a part of the honing grindstone for gears of FIG. 1, that is, inner peripheral teeth.

FIG. 3 is a perspective view showing a test piece for measuring the strength of a massive grinding wheel G1, a filler G2, and a resin binder contained in the honing wheel for gears of FIG. 1;

FIG. 4 is a diagram illustrating a method for measuring strength using the test piece of FIG. 3;

FIG. 5 is a process chart for explaining a manufacturing process of the honing grindstone for gears in FIG. 1;

6A and 6B are diagrams illustrating a state in which a honing process of a gear is performed using the internal tooth type grindstone of FIG. 1, wherein FIG. 6A is a cross-sectional view taken along aa line in FIG. (b) is a diagram showing a cross section perpendicular to the axial direction.

[Explanation of symbols]

 10: Honing grindstone for gear 12: Main body 14: Inner peripheral tooth 18: Work material (gear) G1: Lumped abrasive G2: Filler PB: Resin binder

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ao Kusakabe 3-36 Noritake Shinmachi, Nishi-ku, Nagoya-shi, Aichi F-term (reference) in Noritake Company Limited 3C058 AA03 AA09 CA01 CB03 3C063 AA02 AB04 BA24 BB08 BB19 BC03 EE03

Claims (2)

[Claims] 1. A honing stone for a gear having a plurality of teeth for meshing with a gear to polish a tooth surface of the gear, wherein a plurality of abrasive grains are combined with an inorganic binder to be larger than the abrasive grains. A honing grindstone for gears, wherein massive abrasive grains having a diameter are bound by a resin binder. Wherein said resin binder are those containing a filler, the strength S _B of the abrasive agglomerates of strength S _G and the resin binder
2. An intensity ratio (S _G / S _B ) with respect to 1.5 or less.
Honing whetstone for gears.