JPH07122445B2 - Bearing device of gear reducer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device of a gear reducer used in various automation and labor-saving equipment and general industrial equipment.

2. Description of the Related Art In conventional gear reduction gears, spur gears have been mainly used, but helical gears with low noise have come to be frequently used due to the recent demand for noise reduction in the market. When a helical gear is used, an axial force is applied to the bearing, but when the bearing is a rolling bearing such as a deep groove ball bearing, there is little problem because it can withstand some axial force. However, when using a sintered oil-impregnated bearing for cost reduction, an axial force is applied to the step portion for fitting the pinion shaft and the end surface of the sintered oil-impregnated bearing on the pinion side. The sintered bearing may wear due to the roughness of the surface roughness, and the bearing may cause seizure of the bearing, resulting in a marked decrease in life. In particular, in order to increase the reduction ratio per reduction gear, it is necessary to reduce the diameter of the pinion shaft, so the contact area between the sintered oil-impregnated bearing and the pinion shaft step becomes small,
Since the axial force per unit area is increased, the wear of the sintered oil-impregnated bearing is further increased.

In order to solve such a problem, conventionally, a thrust washer has been inserted between the sintered oil-impregnated bearing and the stepped portion of the pinion shaft.

A bearing device for such a conventional gear reducer will be described below with reference to FIGS. 6 to 8.

FIG. 6 is a sectional view of a gear reducer using a conventional sintered oil-impregnated bearing, and FIG. 7 is an enlarged view of the sintered oil-impregnated bearing portion in FIG. In the figure, 8 is a gear case, 7 and 14 are ground plates installed in the gear case 8, 5 is a pinion shaft of a motor which penetrates the ground plate 7 and is fitted into the gear case 8, and 4 is a one-stage meshing with the pinion shaft 5 of the motor. Gear, 2 is 1st gear 4
Two-stage pinion shaft in which is pressed, 1,11 are installed on the ground plates 7,14, and a sintered oil-impregnated bearing that holds the two-stage pinion shaft 2,
15 is a thrust washer inserted between the pinion shaft 2 and the sintered oil-impregnated bearings 1, 11, 6 is a two-stage pinion provided on the pinion shaft 2, 9 is an output gear meshing with the pinion 6, and 10 is an output gear 9. The press-fitted output shafts 12, 13 are sintered oil-impregnated bearings installed on the base plates 7, 14 and holding the output shaft 10. The pinion shaft 5 and the first-stage gear 4 of the motor are helical gears, and the second-stage pinion 6 and the output gear 9 are spur gears.

First, the power from the motor is transmitted to the first stage gear 4 through the pinion shaft 5. At this time, since the pinion shaft 5 and the first-stage gear 4 are helical gears, a force is applied to the first-stage gear 4 and the second-stage pinion shaft 2 toward the sintered oil-impregnated bearing 1 or the sintered oil-impregnated bearing 11. . Then, for example, when a force is applied in the direction of the sintered oil-impregnated bearing 1, this force is applied to the sintered oil-impregnated bearing 1 installed on the main plate 7 through the thrust washer 3. Here, since the two-stage pinion shaft 2 is rotating and the sintered oil-impregnated bearing 1 is fixed to the main plate 7, the two-stage pinion shaft 2 and the thrust washer 3 or the thrust washer 3
And the sintered oil-impregnated bearing 1 or both slide.
Regarding the sliding between the two-stage pinion shaft 2 and the thrust washer 3, since the surface roughness of the thrust washer is high and the hardness is also high, there is little wear and it is difficult to cause bearing seizure. Next, regarding the sliding between the thrust washer 3 and the sintered oil-impregnated bearing 1, in addition to the surface roughness of the thrust washer 3 being smaller, the contact area with the sintered oil-impregnated bearing 1 is larger than that when the thrust washer 3 is not inserted. Since it can take a large amount, there is little problem of wear.

Note that FIG. 8 is a sectional view of an essential part in the case of a deep groove ball bearing. In the figure, 2 is a pinion shaft, and this pinion shaft 2
Is fitted in the deep groove ball receiver 16, and the deep groove ball bearing 16 is fixed to the main plate 7 via the housing 17.

In this deep groove ball bearing 16, since the fitting portion 16a of the pinion shaft 2 rotates in coincidence with the pinion shaft 2, the problem due to friction does not occur.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, generally, two types of gear reducers are manufactured, in terms of price, life and strength, one using a deep groove ball bearing and one using a sintered oil-impregnated bearing. However, comparing the one using the sintered oil-impregnated bearing (Fig. 7) with the one using the deep groove ball bearing (Fig. 8), the deep groove ball bearing is used simply by inserting the thrust washer 3. The size of the pinion shaft 2 in the thrust direction must be changed by the thickness t of the thrust washer between the case and the case where the sintered oil-impregnated bearing is used, and the pinion shaft cannot be shared. Further, if the sintered oil-impregnated bearing 1 is shaved by the thickness t of the thrust washer 3 in order to share the pinion shaft, the thickness of the flange portion 1a of the sintered oil-impregnated bearing 1 becomes thin and the strength becomes weak. Next, housing when using deep groove ball bearings
There is a method of adjusting the position of the pinion side end surface of the deep groove ball bearing 16 and the position of the pinion side end surface of the thrust washer when the sintered oil-impregnated bearing is used by changing the dimension of 17, but the axial dimension for installing the gear and pinion is Since it becomes smaller, it may affect the gear strength.

Therefore, the pinion shaft cannot be shared, and it is necessary to manufacture the pinion shaft in accordance with each bearing, which raises the manufacturing cost and complicates the assembly work.

The present invention is to solve the above-mentioned conventional problems, and to prevent wear of the pinion side end surface of the sintered oil-impregnated bearing, and to provide a gear reducer capable of sharing a pinion shaft for both the deep groove ball bearing and the sintered oil-impregnated bearing. An object is to provide a bearing device.

Means for Solving the Problems In order to achieve this object, the bearing device of the gear reducer of the present invention has a depth of the thrust washer and a recess at the end face of the portion where the pinion shaft of the sintered oil-impregnated bearing is fitted. And the thrust washer is arranged in this recess.

Effect With the above configuration, the present invention can make the length of the pinion shaft up to the end surface of the sintered oil-impregnated bearing even if the thrust washer is arranged, and this pinion shaft can also be used in a deep groove ball bearing. . Therefore, since the pinion shaft can be shared, the manufacturing cost can be reduced and the assembling process can be simplified.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a gear reducer according to the first embodiment of the present invention. In FIG. 1, 18 and 21 are sintered oil-impregnated bearings in which recesses 18a and 21a are provided on the end face into which the pinion shaft 19 is inserted, 19 is a two-stage pinion shaft held by the sintered oil-impregnated bearings 18 and 21, and Is a sintered oil-impregnated bearing 18,21 and pinion shaft 19
Thrust washers inserted in between.

In addition, 8 is a gear case, 7 and 14 are ground plates, 5 is a pinion shaft of a motor, 4 is a one-stage gear, 6 is a two-stage pinion, 9 is an output gear, 10 is an output shaft, and 2 and 13 are sintered bearings. Since these are the same as the configuration of the conventional example (FIG. 6), description thereof will be omitted. The depths of the recesses 18a and 21b are the same as those of the thrust washers 20 and 22.
And the diameters of the recesses 18a and 21a are slightly larger than the diameters of the thrust washers 20 and 22.

The operation of the gear reducer configured as described above is the same as the conventional example, but by providing the recesses 18a, 21a in the sintered oil-impregnated bearings 18, 21, the pinion by inserting the thrust washers 20, 21. The dimensional effect of the shaft 19 can be eliminated. Therefore, even in the case of a deep groove ball bearing, the pinion shaft 19 can be used as it is. Further, since the flange portion of the sintered oil-impregnated bearing can have a sufficient thickness, there is no problem in strength.

As described above, according to the present embodiment, the recesses 18a and 21a are provided on the end faces of the pinion shaft 19 fitting portions of the sintered oil-impregnated bearings 18 and 21, and the influence of the thickness dimensions of the thrust washers 20 and 22 on the pinion shaft 19 dimension is influenced. By eliminating it, the pinion shaft can be shared with the case of using the deep groove ball bearing, so that the manufacturing cost can be reduced and the defect occurrence rate due to an assembly error can be reduced. Next, the second aspect of the present invention
Embodiments will be described below with reference to the drawings.

FIG. 3 is a sectional view of a bearing device for a gear reducer according to a second embodiment of the present invention. Since the entire structure of the gear reducer is the same as that of the first embodiment described above, only the bearing portion will be described.

In FIG. 3, reference numeral 7 is a base plate, which is the same as that of the first embodiment. Reference numeral 23 is a sintered oil-impregnated bearing installed on the main plate 7, 24 is a thrust washer press-fitted into a recess 23a provided on the end face of the sintered oil-impregnated bearing 23 where the pinion shaft 19 is fitted, and 19 is retained by the sintered oil-impregnated bearing 23. It is a pinion shaft. As shown in FIG. 4, a groove 26 communicating with the fitting portion of the pinion shaft 19 is provided on the bottom surface of the recess 23a of the sintered oil-impregnated bearing 23.

Further, the sintered oil-impregnated bearing 23 is installed on the main plate 7 so that the hydraulic pressure in the sintered oil-impregnated bearing during operation becomes highest in the groove 26 portion.

The operation of the bearing device of the gear reducer configured as described above will be described below.

Since the thrust washer 24 is press-fitted into the sintered oil-impregnated bearing 23, the thrust washer 24 slides between the step portion of the pinion shaft 19 and the thrust washer 24 while receiving an axial force. Here, since the thrust washer has a small surface roughness and a high hardness, the abrasion due to this sliding is small and the seizure of the bearing portion can be prevented. When the pinion shaft 19 rotates, an oil film 25 is formed between the pinion shaft 19 and the sintered oil-impregnated bearing 23 as shown in FIG. 5, and the sintered oil-impregnated bearing 23 and the pinion are provided near a where the groove 26 is provided. The oil pressure between the shaft 19 is maximum. Sintered oil-impregnated bearing 23
When the pressure of the oil inside increases, the oil oozes out from the end surface of the sintered oil-impregnated bearing 23. The oil that oozes out collects in the film 26, and when the pinion shaft 19 stops rotating, the oil-impregnated bearing sintered from the groove 26
23 Returned inside.

As described above, according to the present embodiment, the concave portion of the sintered oil-impregnated bearing 23
A groove 26 communicating with the fitting portion of the pinion shaft 19 is provided on the bottom surface of 23a, the thrust washer 24 is press-fitted into the recess 23a, and the groove 26 is located at a position a where the hydraulic pressure in the sintered oil-impregnated bearing during operation is the highest. Since it is arranged, the oil oozing out from the end surface of the sintered oil-impregnated bearing 23 can be effectively returned to the inside of the bearing when the rotation of the pinion shaft 19 is stopped, and the life of the bearing can be extended.

In the first embodiment, the pinion shaft 5 and the first-stage gear 4 of the motor are helical gears as in the conventional example.
The motor pinion shaft 5 and the first stage gear 4 may be spur gears, and the second stage pinion 6 and the output gear 9 may be spur gears as in the conventional example, but the second stage pinion 6 and the output gear 9 may be helical gears. . Further, although the number of reduction stages of the gear reducer is two, the number of reduction stages of the reducer may be any number of stages, and the bearing of the present invention is used only in the bearing device at both ends of the two-stage pinion shaft 19. It goes without saying that the device can be used for some or all of the bearings of the gear reducer, and it goes without saying that some of the bearings may be bearings that are not sintered oil-impregnated bearings such as deep groove ball bearings.

Further, in the second embodiment, the groove 26 is installed only in one place, but a plurality of grooves 26 may be installed in one sintered oil-impregnated bearing, and the thrust washer 24 and the sintered oil-impregnated bearing 23 are provided. Although the fixing method of (1) was press-fitting, it may be adhesion. Further, although the thrust washer 24 has a disk shape, it goes without saying that the thrust washer 24 does not have to have a disk shape.

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, a recess having a depth equal to the thickness of the thrust washer is provided on the end face of the portion of the sintered oil-impregnated bearing into which the pinion shaft is fitted, and the thrust washer is arranged in this recess. By doing so, it is possible to prevent wear of the end surface of the sintered oil-impregnated bearing on the pinion shaft side due to axial force without reducing the strength of the bearing, and to prevent the pinion shaft dimension from being reduced by inserting the thrust washer. Since the pinion shaft can be shared even when the deep groove ball bearing is used, the cost can be reduced by reducing the inventory and reducing defects due to assembly mistakes.

Furthermore, if a groove is provided on the bottom surface of the recess of the sintered oil-impregnated bearing that communicates with the part where the pinion shaft fits, the oil that oozes out from the end surface of the sintered oil-impregnated bearing when the pinion shaft rotates is effectively sintered when the pinion shaft rotation stops It is possible to realize a bearing device of a gear reducer that can be returned to the inner diameter surface of the bearing and can have a number of excellent effects such as extending the life of the bearing.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a gear reducer according to a first embodiment of the present invention, FIG. 2 is a detailed view of a bearing portion of FIG. 1, and FIG. 3 is a second view of the present invention. 4 is a perspective view of the sintered oil-impregnated bearing shown in FIG. 3, and FIG. 5 is an operation explanatory view of the second embodiment of the present invention. FIG. 6 is a cross-sectional view of a conventional gear reducer, FIG. 7 is a detailed view of the bearing portion of FIG. 6, and FIG. 8 is a detailed view of a bearing device main part when a deep groove ball bearing is used in the bearing device. . 4 ... Single gear, 18, 21, 23 ... Sintered oil-impregnated bearing, 18a, 21a,
23a ... recess, 19 ... pinion shaft, 20,22,24 ... thrust washer, 25 ... oil film, 26 ... groove.

Claims (2)

[Claims] 1. A pinion shaft provided with a gear, a sintered oil-impregnated bearing that rotatably supports the pinion shaft, and a thrust washer disposed between the pinion shaft and the sintered oil-impregnated bearing. A bearing device for a gear reducer, wherein a recess having a depth equal to the thickness of the thrust washer is provided on an end surface of a portion of the sintered oil-impregnated bearing into which the pinion shaft is fitted, and the thrust washer is disposed in the recess. 2. A bottom surface of a recess that contacts the thrust washer,
The bearing device for a gear reducer according to claim 1, wherein at least one groove is provided which communicates with a portion into which the pinion shaft is fitted.