JP2010060142A - Gear reduction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear reduction device in which backlash noise caused in no or light-load operation is suppressed by taking a measure in which a load application on a gear-shaft to removing the backlash noise is checked, and a member for applying a light friction-load on the gear shaft is inserted in the inside of the gear case. <P>SOLUTION: A pair of axially opposing side-sheets 2, 3 is provided in the inside of the gear case 1; the side-sheets 2, 3 are supported by means of a spacer so as to maintain the opposing state at a constant interval. Installation holes 2b, 3b for attachment of baring housings 12, 13 are made in the side-sheets 2, 3. The bearing housing 12, 13 are fit in the installation holes 2b, 3b. As a member which applies a light load by constant friction on the gear shaft, an O-ring 14 or an oil seal 36 is provided between bearings 10, 11 and 18, 19 for supporting either one of gear-shafts 9 and 16 of a first gear 7 in mesh with the rotating shaft 6 of a motor, or a second gear 17, and bearing housings 12, 13 and 20, 21. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gear reducer used for a motor or the like, and more particularly, to a gear reducer that reduces noise such as gear backlash noise and resonance noise.

  Conventionally, gear reduction devices have been devised to solve various problems caused by gear backlash. Backlash is play when gears mesh with each other. In a gear reducer, play between gears is indispensable. Because there is play, smooth rotation is obtained. However, backlash occurred due to this play, and the following problems occurred. That is, due to the vibration of the motor, the mating gear contacts the tooth surface opposite to the transmission direction, and noise is generated. This noise is noticeable when the actual load applied to the output shaft of the gear reducer is light or no load is applied.

  Conventionally, in order to eliminate such a problem caused by backlash, there has been proposed a machine or the like in which gears are doubled and the phase is shifted by the amount of backlash so that the two tooth surfaces mesh with the backlash 0 state.

JP-A 63-262042 Japanese Utility Model Application No. 5-052931 (CD-ROM of Japanese Utility Model Application Publication No. 7-018058)

  However, since this method requires extremely high accuracy in manufacturing, the cost is high, and it cannot be used for an inexpensive gear reducer. Moreover, even with this method, it is not possible to desire a smooth operation equivalent to that of a gear reducer with backlash.

  The present invention has been made paying attention to such a conventional problem, and confirms in advance the amount of gear shaft load necessary to eliminate backlash noise, and a member for applying a slight friction load to the gear shaft is mounted inside the gear case. Accordingly, an object of the present invention is to provide a gear reducer that can remove backlash noise generated at no load and light load.

  In order to solve the above-mentioned problems, the present invention is a gear case, and is accommodated in the gear case. The rotating shaft of the electric motor is used as an input shaft, and rotational force from a gear provided on the rotating shaft is transmitted to an output shaft. A gear reduction gear including a predetermined number of reduction gears, a gear shaft fitted in the reduction gear, a bearing that supports the gear shaft, and a bearing housing that houses the bearing and is disposed in the gear case. In the machine, a pair of side plates facing each other in the axial direction are provided inside the gear case, and these side plates are supported via spacers so as to keep facing each other at a predetermined interval, and the side plate includes the bearing housing. The first housing or the second gear of the next stage engages with the rotating shaft of the electric motor. Between the bearings supporting the gear shaft of either the said bearing housing, in the provision of the O-ring or oil seal as a member for applying a light load with a constant friction to the gear shaft.

  According to the first aspect, it is possible to reduce noise such as gear backlash and resonance.

It is sectional drawing which shows 1st Embodiment of the gear reducer by this invention. It is a partial expanded sectional view of FIG. It is a partial expanded sectional view which shows 2nd Embodiment of the gear reducer by this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows a first embodiment of a gear reducer according to the present invention, and FIG. 2 is an enlarged view of a part of FIG.

  1 and 2, reference numeral 1 denotes a gear case, which is a cylindrical case with one closed. Inside the gear case 1, a pair of side plates 2 and 3 that are opposed to each other in the axial direction are disposed with the outer peripheral surface in contact with the inner wall surface 1 a of the gear case 1. The side plates 2 and 3 are supported by a plurality of spacers 4 so as to maintain an opposing state at a constant interval. The side plate 3 disposed on the gear case lid 1 b side is fixed to the gear case 1 lid 1 b via a screw 5.

  The side plate 2 on the opening 1c side of the gear case 1 is formed with a hole 2a into which the output shaft 6 of the motor to which the gear case 1 is assembled is inserted. An output shaft 6 of the motor is introduced into the gear case 1 from the hole 2 a of the side plate 2 of the gear case 1, and transmits rotation to a gear side large gear 7 provided in the gear case 1. A gear is formed on the output shaft 6 of the motor to constitute a motor side small gear 8, and the rotation is transmitted from the motor side small gear 8 to the gear side large gear 7.

  The gear-side large gear 7 is supported by a first-stage shaft 9 with a small gear serving as an input shaft. The first-stage shaft 9 with a small gear is supported by bearings 10 and 11 mounted on the side plates 2 and 3. These bearings 10 and 11 are accommodated in bearing housings 12 and 13, respectively, and these bearing housings 12 and 13 are fitted and attached to mounting holes 2 b and 3 b formed in the side plates 2 and 3. A bearing housing 13 that houses the bearing 11 incorporates an O-ring 14 that is in sliding contact with the first stage shaft 9 with a small gear. The O-ring 14 gives a load due to constant friction to the first stage shaft 9 and reduces backlash noise or resonance noise.

  The small gear 15 of the first stage shaft 9 with a small gear meshes with a reduction large gear 17 supported by the next second stage gear shaft 16. The gear shaft 16 is supported by bearings 18 and 19 mounted on the side plates 2 and 3. These bearings 18 and 19 are accommodated in bearing housings 20 and 21, respectively. The bearing housings 20 and 21 are fitted and attached to mounting holes 2 c and 3 c formed in the side plates 2 and 3.

  A small reduction gear 22 is supported on the gear shaft 16 together with the reduction large gear 17, and the reduction small gear 22 meshes with a reduction large gear 24 supported by a third-stage gear shaft 23. The third gear shaft 23 is also supported by bearings 25 and 26 mounted on the side plates 2 and 3. These bearings 25 and 26 are accommodated in bearing housings 27 and 28, respectively, and these bearing housings 27 and 28 are fitted and attached to mounting holes 2d and 3d formed in the side plates 2 and 3, respectively.

  The third stage gear shaft 23 supports a reduction small gear 29 together with the reduction large gear 24, and the reduction small gear 29 meshes with a reduction large gear 31 supported by the output shaft 30. The output shaft 30 is supported via bearings 32 and 33. The bearing 32 is supported by the mounting hole 2e of the side plate 2 via the bearing housing 34, and the bearing 33 is supported by the mounting hole 3e of the side plate 3 and the bearing housing portion 35 formed in the lid portion 1b of the gear case 1. Yes. The tip of the output shaft 30 is led out to the outside of the lid 1b of the gear case 1 and the rotation is taken out.

  Next, the operation of the embodiment having the above configuration will be described. The rotation of the output shaft 6 of the motor is transmitted from the motor side small gear 8 to the gear side large gear 7. The backlash noise is mainly generated between the motor side small gear 8 and the gear side large gear 7 at no load and light load. This is because the counterpart gear contacts the tooth surface on the side opposite to the teeth in the transmission direction when there is no load or light load due to motor vibration. Therefore, backlash noise is suppressed by applying a light load that does not generate gear play during rotation to the first stage shaft 9 that is coaxial with the gear-side large gear 7 in advance. Along with the rotation of the gear side large gear 7, the first stage shaft 9 with a small gear rotates. An O-ring 14 built in a bearing housing 13 in which the bearing 11 is housed is in sliding contact with the first stage shaft 9 with a small gear. In this way, a light load due to constant friction is applied to the first-stage shaft 9 by the O-ring 14, so that backlash noise or resonance noise can be reduced. For setting the load force at that time, it is necessary to set a light load that does not cause motor vibration and that does not lose the motor output as much as possible.

  Thus, the small gear 15 of the first stage shaft 9 with a small gear whose backlash noise is reduced transmits the rotation to the reduction large gear 17 supported by the next second stage gear shaft 16. Since the number of teeth of the reduction large gear 17 is greater than that of the small gear 15, the rotation of the first stage shaft 9 is decelerated and transmitted to the second stage gear shaft 16. Thus, the rotation of the small gear 15 is reduced and transmitted to the reduction large gear 17, and is transmitted from the reduction small gear 22 of the gear shaft 16 to the reduction large gear 24 supported by the third stage gear shaft 23. The rotation of the reduction large gear 24 is transmitted from the reduction small gear 29 supported by the third stage gear shaft 23 to the reduction large gear 31 supported by the output shaft 30. The rotation of the reduction gear 31 is transmitted to the outside through the output shaft 30. Thus, the rotation of the output shaft 6 of the motor is taken out from the output shaft 30 as a rotation reduced to a predetermined speed by the gear ratio by the gear reducer.

  Next, FIG. 3 shows a second embodiment of the present invention in which the same parts as those in FIG. 2 are denoted by the same reference numerals and the description of the same parts is omitted. In this case, an oil seal 36 is used in place of the O-ring 14 in order to apply a light load due to constant friction to the first stage shaft 9. The oil seal 36 is built in a bearing housing 37 that houses the bearing 11. Since this bearing housing 37 incorporates an oil seal 36 disposed on the outer peripheral surface of the first stage shaft 9, a housing part 37 b having a larger inner diameter than the housing part 37 a for housing the bearing 11 is extended around the first stage shaft 9. Formed.

  Also in this case, the oil seal 36 applies a light load to the first stage shaft 9 and reduces backlash noise. In the above embodiment, the O-ring or the oil seal 36 is applied as a member for applying a light load to the bearing housing 13 or 37 in which the bearing 11 of the first stage shaft 9 is housed. It may be applied to the housing 12 or may be applied to the bearing housings 20 and 21 of the two-stage shaft 16. These members that give a light load can be applied to a plurality of bearing housings, and different types of members can be used in combination. Further, in the above embodiment, a member that gives a light load is arranged between the bearing housing and the shaft, and a slight load is directly given to the shaft, but between the bearing and the bearing housing, A light load can also be provided indirectly by providing a member that applies a light load. In addition, it cannot be overemphasized that it can change suitably and can implement within the range which does not change the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Gear case 2, 3 Side plate 6 Motor output shaft 7 Gear side large gear 8 Motor side small gear 9 First stage shaft with small gear 10, 11, 18, 19, 25, 26 Bearing 12, 13, 20, 21, 27, 28 , 37 Bearing housing 14 O-ring 15 Small gear 16 Second stage gear shaft 17, 24 Reduction large gear 22, 29 Reduction small gear 23 Third stage gear shaft 30 Output shaft 36 Oil seal

Claims (1)

A gear case, a predetermined number of reduction gears that are housed in the gear case and that use the rotation shaft of the motor as an input shaft, and transmit the rotational force from the gear provided on the rotation shaft to the output shaft, and the reduction gear In a gear reducer comprising an inserted gear shaft, a bearing that supports the gear shaft, a bearing housing that houses the bearing and is disposed in the gear case,
A pair of side plates facing each other in the axial direction are provided inside the gear case, and these side plates are supported so as to be kept facing each other at regular intervals through spacers, and the side housing is attached to the bearing housing. The bearing housing is provided with a bearing that supports the gear shaft of either the first gear or the second gear of the next stage, which is provided with a hole, is fitted into the mounting hole, is attached to the bearing housing, and meshes with the rotating shaft of the electric motor. A gear reducer characterized in that an O-ring or an oil seal is provided as a member for applying a light load due to constant friction to the gear shaft.

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