JPH0727208A - Gear type power transmission device - Google Patents

Abstract

PURPOSE:To reduce tooth contact noises when a tooth contact surface is changed over and under the normal operation without reducing a power transmission ratio. CONSTITUTION:At least two gears 1, 2, each made of electroconductive material, are meshed with each other. A first means 1 supplies electroviscous fluid 5 as lubricant to the meshing porion between the gears 1 and 2. A second means causes potential difference between the gears 1 and 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear type power transmission device.

[0002]

2. Description of the Related Art In a conventional gear type power transmission device, a backlash is always provided at a meshing portion of two gears to prevent seizure and breakage, and lubricating oil is provided to reduce wear of tooth surfaces. It is being supplied. Tooth contact noise during normal operation is comparatively loud, and it has been proposed to use high-viscosity lubricating oil and to make the lubricating oil located at the meshing portion function as a damper in order to reduce this. , Such lubricating oil becomes a large resistance to gear operation when it is agitated from the oil sump for supplying to the meshing part or when stirring when the gear housing is filled with lubricating oil It significantly reduces the transmission rate.

Since the above-mentioned backlash is provided in the meshing portion, the tooth contact surface is instantaneously switched to the opposite side by the inertial force of the gear on the other side when the rotation of the drive side gear is reduced. A relatively large tooth contact noise is generated, and the impact force at this time reduces the mechanical life of the gear. In order to improve this problem without lowering the power transmission rate, Japanese Patent Application No. 2-18283 discloses that an electrorheological fluid whose viscosity is increased by applying a voltage is used as a lubricant to cut a tooth contact surface. There is described a gear type power transmission device that increases the viscosity only when it is changed and exhibits a sufficient damper effect.

[0004]

According to the above-mentioned conventional technique, the tooth contact noise when the contact surface of the tooth is switched and the reduction of the life due to the impact force are prevented. Since a voltage is applied to the entire electrorheological fluid as a lubricant in (1) to increase its viscosity, it is not possible to reduce the tooth contact noise during normal operation.

Therefore, an object of the present invention is to provide a gear type power transmission device capable of reducing the tooth contact noise when the tooth contact surface is switched and during normal operation without reducing the power transmission efficiency. That is.

[0006]

A gear type power transmission device according to the present invention comprises at least two gears formed of an electrically conductive material and meshing with each other, and an electrorheological fluid as a lubricant at a meshing portion between the two gears. And a second means for applying a potential difference between the two gears.

[0007]

In the gear type power transmission device described above, the electro-rheological fluid as the lubricant is supplied to the meshing portion between the two gears by the first means, and the potential difference is given between the two gears by the second means. The viscosity of the electrorheological fluid is increased only at the meshing portion.

[0008]

1 is a schematic sectional view showing an embodiment of a gear type power transmission device according to the present invention. In the figure, 1 is a first gear connected to a crankshaft (not shown) of the reciprocating engine, and 2 and 3 are second and third gears connected to a pair of balance shafts (not shown). Each of the pair of balance shafts has a counterweight, and functions to reduce vibration due to reciprocal movement of the piston.

As shown, the first gear 1 meshes with a second gear 2 arranged below it, and the second gear 2 meshes with a third gear 3 arranged laterally thereof. . In particular, the second gear 2 and the third gear 3 have the same number of teeth, and the first gear 1 has twice the number of teeth. As a result, as the crankshaft rotates, both balance shafts rotate in opposite directions at twice that speed.

Reference numeral 4 denotes a housing for accommodating these gears, and an electrorheological fluid 5 as a lubricant is provided in the lower portion of the housing so as to immerse both gears below the meshing portion of the second and third gears 2 and 3. It is included. This electrorheological fluid 5 is
For example, it is a solution in which fine particles of starch or silica gel are dispersed in mineral oil, the viscosity of which increases when a voltage is applied. As the second and third gears 2 and 3 rotate, the electrorheological fluid 5 in the lower part of the housing becomes
And the first and second gears 1 and 2 are agitated.

All the gears 1, 2, 3 are made of a conductive material such as steel and are electrically insulated from the housing 4. Further, the gears 1, 2 and 3 which rotate using an electric brush (not shown) or the like are always provided with a predetermined potential difference between the two gears that mesh with each other. At this time, which gear has the highest potential is free, and for example, the first gear 1 is the highest potential and the potentials of the second and third gears 2 and 3 are sequentially lowered, or the second gear 2 is As the highest potential, the potentials of the first and second gears 1 and 3 may be set to the same lower potential.

In the gear type power transmission device having the above-described structure, when the balance shaft is driven by the crankshaft through the first, second and third gears 1, 2, 3 the gears are disturbed by the meshing portions. The raised electrorheological fluid is increased in viscosity at this position because a potential difference is applied between the two gears that mesh with each other, and is maintained at a low viscosity in the lower portion of the housing 4. Therefore, the resistance to the operation generated when the second and third gears 2 and 3 agitate the electrorheological fluid is kept low, the power transmission efficiency is not reduced, and the tooth flanks of both gears during normal operation are maintained. The hit is softened by the damper effect of the highly viscous lubricant, and the hit sound is sufficiently reduced.

Further, a backlash is always provided in the meshing portion to prevent seizure and breakage, and when the rotation speed of the first gear 1 sharply decreases with the crankshaft,
Due to the inertial force of the second gear 2, the tooth contact surfaces of both gears 1 and 2 are momentarily switched to the opposite side, and a normally large tooth contact noise is generated, and the impact force at this time is Reduces mechanical life. However, this collision is softened by the highly viscous lubricant as before,
Tooth contact noise is also significantly reduced, and a reduction in mechanical life is prevented. The same applies to the meshing portion of the second and third gears 2 and 3.

When the backlash in the meshing portion of the gear is set too small, seizure and breakage easily occur, and when it is too large, the aforementioned impact force becomes large and the mechanical life is shortened. Usually, it took a lot of time to make fine adjustments, but since the above-mentioned impact force is alleviated by the high-viscosity lubricant in this way, it does not matter so much for large parts, Assembling time can be shortened.

[0015]

As described above, according to the gear type power transmission device of the present invention, the electrorheological fluid as a lubricant is provided in the meshing portion between at least two gears that are meshed by the first means and made of a conductive material. Is supplied and a potential difference is applied between the two gears by the second means, so that the viscosity of the electrorheological fluid is increased at the meshing portion and the viscosity is maintained low at other positions. Therefore, the resistance to the operation generated when the electrorheological fluid as the lubricant is agitated to be supplied to the meshing portion or when the gear housing is filled with the lubricant is kept low, and the resistance to the operation is kept low. The transmission efficiency is not reduced, and the tooth contact noise during normal operation and when the tooth contact surface is switched is reduced by the damper effect of the highly viscous lubricant.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a gear type power transmission device according to the present invention.

[Explanation of symbols]

 1 ... 1st gear 2 ... 2nd gear 3 ... 3rd gear 4 ... Housing 5 ... Electrorheological fluid

Claims (1)

[Claims] 1. At least two gears formed of an electrically conductive material and meshing with each other, and first means for supplying an electrorheological fluid as a lubricant to a meshing portion between the two gears.
A second means for applying a potential difference between the two gears, and a gear type power transmission device.