JPH02275165A - Reduction gear - Google Patents

Abstract

PURPOSE:To realize a quiet noise of a reduction gear by holding one sides of driving shafts with bearings larger than the diameter of the driving shafts near the both ends of the driving shafts, and pressing the shafts from one ends to the other ends elastically. CONSTITUTION:The side walls 1a and 1b of a box body 1 made of a resin are bent in a projection form to the inner side to obtain an elasticity. The side walls 1a and 1b are contacted to the ends of the first and the second driving shafts 7 and 8, and a moving force is given to the driving shaft 7 and the driving shaft 8 in the axial direction respectively by the side walls 1a and 1b. By this moving force, the driving shafts 7 and 8 are stabilized under the condition to be pressed to one side surfaces of the shaft receiving grooves 11 and 12. The generation of noise can be reduced consequently.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speed reduction device for a video tape recorder, an audio tape recorder, etc.
In particular, when the rotation of the first drive shaft of the reduction gear is transmitted to the second drive shaft via gears, 1. The purpose is to reduce the noise generated by gear meshing fluctuations caused by the gap between the drive shaft and the bearing.

Conventional Technology Traditionally, in order to miniaturize the equipment, there has been a trend to use small, high-speed motors as motors to drive the mechanisms of audio and video tape recorders, and to reduce the speed of the motors and use them as driving power. be.

An example of a conventionally used configuration of this speed reduction device is shown in FIGS. 2 and 3. In the figure, reference numeral 1 denotes a housing, in which a motor 2 is fixed, and a first pulley 3 is press-fitted onto the motor shaft 2a. 7 has a second gear 4 and a first gear 6 at both ends, respectively.
The first drive shaft is fixed to a first drive shaft and is freely rotatably inserted into a first bearing groove 11 formed in the housing 1. 8
is a second drive shaft to which second and third gears 6 and 9 are respectively fixed at both ends, and the first gear 6 and It is rotatably inserted in a state where it meshes with the second gear 6. and a first bearing groove inserted into the first and second bearing grooves 11.12.
As shown in FIG. 3, the second drive shafts 7 and 8 are each configured with a stopper piece 13 to prevent them from coming off from the bearing grooves 11 and 12. In other words, motor shaft 2! The rotation of L is transmitted to the first drive shaft 7 by the belt 10 stretched between the data IJ-3 and IJ-4.
The rotation of the drive shaft 7 is transmitted to the second drive shaft 8 by the first and second gears 6.6. Note that the rotation of the motor 2 can be decelerated by arbitrarily setting the diameter ratio and tooth number ratio of the first pulley 3 and the second pulley 4 and the first gear 6 and the second gear 6. and is transmitted to the third gear 9, which serves as the output gear. Also,
first and second bearing grooves 11 formed in the housing 1;
The inner diameter Di+D2 of the drive shaft 12 is set to be slightly larger than the outer diameter 111yd2 of the first drive shaft 7 and the second drive shaft 8, and furthermore, the drive shaft 7 and the drive shaft 8 are The first and second bearing grooves 11 and 12 are formed on the drive shaft 7 so that the bearing portion of the body 1 rotates with less frictional resistance.
, 80 is configured to be supported only near both ends.

Problems to be Solved by the Invention However, the housing 1 is generally made of a resin molded product in order to reduce weight and cost, and therefore it is difficult to improve dimensional accuracy, and the distance D1+'' between each bearing groove 11.12 is large. 2 is made larger than necessary.-As a result, the first drive shaft 7 and the second drive shaft 8 are not held in the sieve body 1 and become unstable, as shown in FIG. Noise is generated due to the shaft striking the housing, and the parallelism between the drive shaft 7 and the drive shaft 8 changes during rotation, causing meshing between the first Q gear 5 and the second gear e. There was a problem in that the amount of noise fluctuated and generated noise.

The present invention solves these conventional problems and provides a speed reduction device that generates less noise.

Means for Solving the Problems The speed reduction device of the present invention molds the side surface of the casing into an elastic shape, and utilizes the elastic force to apply a pressing force from the longitudinal direction of the drive shaft. The structure is such that the posture of the bearing groove is stabilized.

Effects According to the above configuration, the pressing force from the axial direction generates a force to move the drive shaft in the width direction of the bearing groove, and this movement force stabilizes the drive shaft in a state where it is pressed against one side of the bearing groove. In addition, impactful abutment between the drive shaft and the side wall of the bearing groove is prevented, thereby reducing the noise generated, and the distance between the drive shafts is kept constant, so the contact between the gears is reduced. The meshing is also kept constant, and noise due to meshing fluctuations can be reduced.

Embodiment FIG. 1 shows an embodiment of the reduction gear device of the present invention.
The difference from the conventional structure shown in FIG. 2 is that the side walls 1 & 1b of the casing 1 made of resin are bent inward in a convex shape to impart elastic force. 1
and the end of the second drive shaft 7°8, and the side walls 11L and 1b apply axial moving force to the drive shaft 7 and the drive shaft 8, respectively.

Due to this moving force, the drive shafts 7 and 8 are stabilized in a state where they are pressed against one side of the bearing grooves 11 and 12, respectively, as shown in FIG. 1, and as a result, the generation of noise is reduced. be. Note that both ends of the drive shafts 7 and 8 are made spherical in order to reduce resistance during rotation of the first and second drives @ 7 and 8 due to contact between the side walls 11L and 1b. The contact with the side walls 1a and 1b is configured to be a point contact.

Further, in the embodiment, an example was shown in which moving force in the axial direction was applied to both the first and second drive shafts 7.8, but the effect can be expected even if only one of them is used.

Effects of the Invention As described above, according to the present invention, the noise reduction device can be made quiet by simply changing the shape of the side wall of the housing and pressing the motion shaft without improving the dimensional accuracy of the bearing of the housing. This is something that will be promoted.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view of a speed reduction device according to an embodiment of the present invention, FIG. 2 is a partially cutaway plan view of a conventional speed reduction device, and FIG. Figure 4 is
FIG. 3 is a partially cutaway plan view of the same part in an operating state. 1... Housing, 11, 1b... Elastic body bearing part, 2... Motor, 2 &... Motor rotating shaft, 3...・Pulley (1st), 4...
...Pulley (2nd), 6...Gear (1st),
θ...Gear (second), 7...1 drive shaft (first), 8..., drive shaft (second), 9...
...Output gear, 10...Belt, 11.12
...... Housing radial direction bearing section, 13...
・Retaining piece, Dl, Dl...Inner diameter of housing bearing part,
dl, d2...Outer diameter of drive shaft. Name of agent: Patent attorney Shigetaka Awano and 1 other person 1st
Figure 3 I-Direct stop cblb ---51 body 11. 5-=IIl (ml) 8- Kankyoku (寥2) H, I2--- Fujiful direction axis

Claims (1)

[Claims] A motor that generates rotational force, a first drive shaft to which rotation of the motor is transmitted via a belt, and a second drive shaft to which rotation of the first drive shaft is transmitted via gears. and at least one of the first and second drive shafts is held by a bearing having a diameter larger than that of the drive shaft in the vicinity of both ends thereof, and is more elastically supported than the other end of the shaft. A speed reduction device characterized in that it is pressed at the end.