JPH029151Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a gear reduction mechanism, and particularly to a gear reduction mechanism suitable for a rotational drive device.

BACKGROUND TECHNOLOGY There has been a shock absorber using a dart pot. In this shock absorber, the buffering efficiency changes depending on the diameter of the communication hole provided in the piston of the dart pot. By utilizing this phenomenon, for example, as shown in Figure 2,
Flow holes 1, 2 with different diameters provided in the piston,
There is a mechanism for varying the buffering efficiency using a tube 4 having a diameter of 3 and a rotating member 5 provided within the tube 4.
In this device, one of the communication holes _{1 to 3 is selected by rotating the rotating member 5, for example, 90 degrees in the direction of the arrow A1} or _A2 , and one of the cylinders communicating with the inside of the pipe 4 separated by the piston is selected. The buffering efficiency is varied by varying the amount of fluid flowing between the chamber and the other chamber of the cylinder that communicates with the outside of the pipe 4. The rotating member 5 described above is driven by a rotational drive device.

The conventional rotary drive device uses a gear reduction mechanism with a spur gear wheel train to reduce the rotation of the motor and obtain sufficient torque to rotate the rotating member 5. Further, the rotation stop position of the rotating member 5 must be accurate, and a large load is applied to the gear reduction mechanism when the rotating member 5 stops rotating.

Problems that the invention aims to solve In a conventional gear reduction mechanism using a spur gear train, the number of gears increases as the reduction ratio increases, and if the number of gears is not increased, it is necessary to increase the gear ratio of the gears that mesh. There is. For this reason, the efficiency of transmitting the motor rotational force to the rotating member 5 deteriorates, the generation nozzle becomes large, and furthermore, when the gear reduction mechanism is downsized, there are problems in that the workability and durability of each gear deteriorate.

Therefore, an object of the present invention is to provide a gear reduction mechanism that solves the above problems by providing an intermediate gear, a fixed gear and a driven gear that mesh with the intermediate gear, and a slip mechanism on the fixed gear.

Means for Solving the Problems In the present invention, the intermediate gear is eccentrically attached to the rotating drive shaft, meshes with the fixed gear, and rotates and revolves by the gear of the drive shaft.
Further, the intermediate gear meshes with a driven gear having a difference in the number of teeth with respect to the fixed gear, the driven gear rotates at a reduced speed according to the difference in the number of teeth, and an output rotating shaft fixed to the driven gear rotates. Between the fixed gear and the fixed member that inserts and supports the fixed gear, there is a spring member that biases the fixed gear in a direction to separate from the fixed member, and a spring member that is threadedly inserted into the fixed member to form a V-shaped shape on the outer periphery of the fixed member. A slip mechanism is provided with a screw member that engages with the groove and presses the fixed gear against the fixed member against the bias of the spring member according to the insertion amount, so that the torque applied to the fixed gear from the intermediate gear is reduced. When the predetermined value is exceeded, the fixed gear is rotated relative to the fixed member.

Effects In the present invention, the number of gears is small, making it possible to downsize and generate less noise. Furthermore, since there is a slip mechanism consisting of a spring member and a screw member when rotation is stopped, no overload is applied to each gear and its rotating shaft, improving durability.

Embodiment FIG. 1 shows a sectional view of an embodiment of a gear reduction mechanism of a rotary drive device according to the present invention. In the figure, 11 is a drive shaft driven by a motor. Drive shaft 1
A hole is bored at an eccentric position at the tip of the gear 1, and an intermediate gear shaft 12 is press-fitted into this hole. The intermediate gear 13 is rotatably supported by the intermediate gear shaft 12, and the number of teeth of the gear provided on its outer periphery is, for example, about 30. The fixed gear 14 is an internal gear centered on the drive shaft 11, and has, for example, 99 teeth. The fixed gear 14 is fitted and supported by a fixed member 15 having an inner shape corresponding to its outer shape. The fixed gear 14 meshes with the intermediate gear 13 in a shifted state.

The driven gear 16 is an internal gear whose inner and outer diameter dimensions are substantially the same as those of the fixed gear 14, and the number of teeth thereof is greater than that of the fixed gear 14, for example, "102".
The driven gear 16 is fixed to an output rotation shaft 17 whose shaft center coincides with the drive shaft 11, and the intermediate gear 13 meshes with the driven gear 16 without displacement. The output rotating shaft 17 is supported by a bush 19 provided on the fixed part 18. The output rotating shaft 17 rotates the rotating member 5 shown in the second figure.

Incidentally, a groove 14a having a substantially V-shaped cross section is bored on the outer periphery of the fixed gear 14, and a recess 14b is formed on the circumference at the bottom through which the drive shaft 11 of the fixed gear 14 is inserted.
is drilled. The fixed gear 14 accommodates the wave spring 21 in the recess 14b and is inserted into the fixed member 15. At this time, the fixed gear 14 is biased by the wave spring 21 in a direction in which it is separated from the fixed member 15 (in the upper direction in the figure). Fixed gear 14 is connected to wavy spring 21
When inserted into the fixing member 15 against the
There are a total of 3 locations at every 120 degrees of rotation angle around 1.
A screw hole 15a is bored. This screw hole 15
A screw 22 having a substantially conical tip is screwed into the groove 14a and engaged with the groove 14a. The above wavy spring 21
A slip mechanism is constituted by the screws 22 and the like. When the insertion amount of the screw 22 is large as shown in FIG. The frictional force becomes large. Further, as shown in FIG. 3B, when the insertion amount of the screw 22 is small, the pressing force of the groove 14a against the screw 22 is small, and the frictional force of the fixed gear 14 is small.

Furthermore, cylindrical holes 14d as shown in FIG. 4 are bored in the peripheral surface 14c of the fixed gear 14 at three locations at each rotation angle of 120 degrees. After the hole 14d is filled with a lubricant such as grease, a steel ball 23 having the same diameter as the hole 14d is inserted. The depth of the hole 14d is approximately 1/2 of its diameter, and the steel ball 23 protrudes from the hole 14d. On the peripheral surface 16a of the driven gear 16,
A groove 16b whose radius is the distance from the axial centers of the drive shaft 11 and the output rotating shaft 17 to the center of the steel ball 23 is bored. The cross section of the groove 16b is the steel ball 23.
It has a circular arc shape with a diameter smaller than the diameter of the steel ball 23, and the depth is 1/1 of the diameter of the steel ball 23.
Less than 2. The driven gear 16 has the groove 16b connected to the steel ball 2.
3, the peripheral edge surface 16a faces the peripheral edge surface 14c at a small distance, and a thrust bearing structure using steel balls 23 is constructed.

Here, the drive shaft 11 rotates, and the intermediate gear 13 engages with the fixed gear 14 to rotate and revolve. At this time, the fixed gear 14 is fixed to the fixed member 15 by friction, as will be described later. Since the intermediate gear 13 is also meshed with the driven gear 16 at the same time, the driven gear 16 is engaged with the fixed gear 14 by the difference in the number of teeth (difference in the number of teeth between the driven gear 16 and the fixed gear 14) per revolution of the intermediate gear 13. The output rotating shaft 17 rotates at a reduced speed. by the way,
The rotational reduction ratio i of the output rotation shaft 17 with respect to the drive shaft 11 is expressed by the following equation.

i=1−Z ₁ /Z ₂ (1) where Z ₁ is the number of teeth of the fixed gear 14 and Z ₂ is the number of teeth of the driven gear 15.

In this way, the gear reduction mechanism shown in the first figure has a very small number of gears (3) and can be downsized, has a simple structure, and can keep costs low.
Noise generation is also reduced. In addition, the fixed gear 14
Since a thrust bearing structure using steel balls 23 is provided between the driven gear 15 and the driven gear 15, the friction therebetween is reduced and the efficiency of transmitting the rotation of the drive shaft 11 to the output rotating shaft 17 is hardly reduced. In addition, since the output rotating shaft 17 is supported by the bush 19, the structure is simple and can be made compact, and since the gap between the fixed gear 14 and the driven gear 16 is extremely small, the rotation of the intermediate gear 13 is There is almost no leakage of the noise generated by this to the outside.

When the rotation of the output rotating shaft 17 is stopped by stopping the rotation of the rotating member 5, a sudden force is applied to each part of the mechanism shown in the first diagram due to the inertial rotation of the drive shaft 11, intermediate gear 13, etc. At this time, the output rotation shaft 17
Since the driven gear 16 is fixed by stopping the rotation, the fixed gear 14 starts rotating with respect to the fixed member 15 by the intermediate gear 13 that performs inertial rotation.
At this time, the rotational reduction ratio i ₂ of the fixed gear 14 with respect to the drive shaft 11 is expressed by the following equation.

i ₂ =1−Z ₂ /Z ₁ ...(2) Since the slip mechanism is provided between the fixed gear 14 and the fixed member 15 in this way, the intermediate gear is damaged by the force applied when the rotating member 5 stops rotating. axis 12
It is possible to prevent bending of the gear and damage to each of the intermediate gear 13, fixed gear 14, and driven gear 16.

As mentioned above, when the rotating member 5 rotates, the fixed gear 1
4 to the fixed member 15 and to rotate the fixed gear 14 relative to the fixed member 15 when the rotating member 5 is stopped, the torque T required to rotate the fixed gear 14 relative to the fixed member 15 is as follows. Set so that the formula is satisfied.

1/1-Z ₁ /Z ₂・η・T ₀ <T ... (3a) 1/1-Z ₂ /Z ₁・η・T ₀ ≧T ... (3b) However, η is from the drive shaft 11 The transmission efficiency of the rotational force to the output rotation shaft 17, T ₀ is the drive torque of the drive shaft 11.

This torque T is set by varying the insertion amount of the screw 22.

Note that the number of screws 22 and steel balls 23 may be four or more, and an elastic member such as rubber may be used instead of the wavy spring 21. Furthermore, a bearing structure using steel balls 23 is a radial bearing. Any rolling bearing structure may be used as long as the structure includes the following, and is not limited to the above embodiments.

Effects of the Invention As described above, the gear reduction mechanism according to the present invention includes an intermediate gear, a fixed gear and a driven gear that mesh with the intermediate gear, and a slip mechanism comprising a spring member and a screw member between the fixed gear and the fixed member. Because it is established,
It has a simple configuration with a small number of gears and can be miniaturized, reducing costs, generating less noise, and improving durability.Furthermore, the driven gear has a rolling bearing structure and is supported by the fixed gear, so it does not rotate. It has features such as improved power transmission efficiency.

[Brief explanation of the drawing]

Figure 1 is a sectional view of one embodiment of the mechanism of the present invention;
The figure is a diagram for explaining a variable buffer efficiency mechanism to which the mechanism of the present invention is applied, and FIGS. 3 and 4 are enlarged sectional views of each part of the mechanism shown in FIG. 1. 11... Drive shaft, 13... Intermediate gear, 14...
Fixed gear, 14a, 16b...groove, 14b...recess, 14d...hole, 15...fixing member, 15a...
...screw hole, 16...driven gear, 17...output rotating shaft, 21...wavy spring, 22...screw, 23...
wrecking ball.

Claims (1)

[Claims for Utility Model Registration] (1) An intermediate gear eccentrically attached to a rotating drive shaft is meshed with a fixed gear to rotate and revolve, and the intermediate gear has a difference in the number of teeth with respect to the fixed gear. A gear reduction mechanism that meshes with a driven gear to slow down and rotate the driven gear according to the difference in the number of teeth, the fixed gear being interposed between the fixed gear and a fixed member that fits and supports the fixed gear. A spring member that is biased in a direction to separate from the fixed member; and a spring member that is screwed into the fixed member and engages with a V-shaped groove on the outer periphery of the fixed member, and biases the fixed gear according to the amount of insertion. A slip mechanism is provided that includes a screw member that is inserted into and press-contacted to the fixed member against the rotational force, and when the torque applied to the fixed gear from the intermediate gear exceeds a predetermined value, the fixed gear is rotated with respect to the fixed member. A gear reduction mechanism configured to (2) The gear reduction mechanism according to claim 1, wherein the driven gear is supported by the fixed gear using a rolling bearing structure.