JPS60121350A - Planetary speed reduction gear - Google Patents

Abstract

PURPOSE:To provide a speed reduction gear which gives no shock to rotating operation of an input shaft by bringing a pair of planetary gears into pressure contact with opposite tooth surfaces of a sun gear and an internal gear, respectively when the input shaft is not driven. CONSTITUTION:A ring-shaped base 9a of a support arm 9 is rotatably fitted to an output shaft 7 between a support arm 6 integral with an output shaft 7 and an inner race of a bearing 23, and both bending portions 10a, 10b of a U- shaped bending spring 10 engaging with the outside of the circular base 9a are respectively engaged with neck portions of planetary gear shafts 11, 12 inserted through the forward portions of the support arms 6, 9, so that both support arms 6, 9 are urged to turn in the opposite direction to each other by substantially equal turning torque P. Accordingly, at least dring non-driving of an input shaft 1, a pair of planetary gears 5, 8 are respectively brought into pressure contact with opposite tooth surfaces of a sun gear 2 and an internal gear 4 not to give any shock to rotating operation of the input shaft.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a planetary gear reducer used when the rotational direction of an input shaft is frequently changed, such as in a power transmission gear for steering a small transport vehicle.

As shown in FIGS. 1 and 2, a handle 16 is attached to the input shaft 1.
The base of the steering arm 15 is fixed to the output shaft of the planetary gear reducer 14 which is interlocked with the symmetrical tie rods 1.
If the steering device is configured to steer both front wheels 18 through the front wheel shaft arm 17 and the like, the planetary gear reducer 14
Because backlash must be provided between the gears, each time the direction of rotation of the handle is changed, the handle rotates with play according to the back clearance, creating a shock, which worsens the steering feel. This disadvantage is particularly noticeable in planetary gear reducers used in power steering systems.

The present invention deals with this problem, and includes a support arm 6 for one of the planetary gears 5 of a pair of planetary gears that simultaneously mesh with the sun gear 2 provided on the input shaft 1 and the internal gear 4 fixed on the gear box B. is fixed to an output shaft 7, a support arm 9 of the other planetary gear 8 is fitted onto the output shaft so as to be relatively rotatable, and a spring constantly urges the support arm 6.9 to rotate in opposite directions. 1o is attached between both support arms, and at least when the input shaft is not driven, the pair of planetary gears 5 and 8 are connected to the sun gear 2 and the internal gear 4, respectively.
It is characterized by being configured to maintain a state in which it is in elastic contact with mutually opposite tooth surfaces.

3 and 4 show an embodiment of the present invention, in which a gear box 6
An annular internal gear 4 is sandwiched between the cylindrical parts 3a and 3b, and these are integrally connected and fixed with a plurality of bolts 19 and positioning pins 20.
The input shaft 1 is rotatably supported via the shaft 2, and the cylindrical portion 3b.
The output shaft 7, which is rotatably supported via a bearing 26 and a bearing 24 at the tip of the input shaft, has substantially the same rotational axis.

The annular base 9a of the support arm 9 is rotatably fitted to the output shaft 7 between the support arm 6, which is integral with the output shaft 7, and the inner ring of the bearing 26. Both end bent portions 10 of a U-shaped target spring 10 that engages with the outside of the annular base 9a as shown in FIG.
a and 10b are planetary gear support shafts 11.1 inserted into the tip of the supporting arm 6.9 (3), respectively;
2, thereby forcing both support arms 6.9 to rotate in opposite directions with substantially equal rotational force P. Therefore, at least when the input shaft 1 is not driven, the pair of planetary gears 5 and 8 maintain a state in which they are in elastic contact with the opposite tooth surfaces of the sun gear 2 and the internal gear 4, respectively, as shown in the figure.

According to the above configuration, the input shaft 1 moves the sun gear 2 to the fourth gear.
When driven and rotated in the direction of figure A, there is elastic contact between the tooth surface 2a of the sun gear 2 and the tooth surface 5b of the planet gear 5, and the elastic contact between the opposite tooth surface 5a of the planet gear and the tooth surface 4b of the internal gear 4. Via
Since the sun gear directly causes the planetary gear 5 to perform planetary motion, the output shaft 7 is rotated at a reduced speed in the direction A via the support shaft 11 and the support arm 6, while the planetary gear 8
Performs planetary motion by following the .

Furthermore, when the sun gear 2 is driven to rotate in the direction B in FIG. The sun gear directly causes the planetary gear 8 to perform planetary motion through the elastic contact of the opposite tooth surface 4a of the internal gear 4, so that the elasticity of the spring 10 overcomes the load on the output shaft 7. If set, the spindle 12 of the planetary gear 8 transmits rotational force to the spindle 11 of the planetary gear 5 via the spring 10 to decelerate and drive the output shaft 7 in the B direction, and the planetary gear 5 Perform the following planetary motion while the gears are in mesh as shown in Figure 4. Orane1
0 elasticity is set to be weaker than in the above case, and the spring 10 is bent by the load of the output shaft 7, and the tooth surface 5a of the planetary gear 5 is
When the tooth surface 2b of the sun gear 2 contacts the tooth surface 2b of the sun gear 2, and the tooth surface 5b of the sun gear contacts the tooth surface 4a of the internal gear 4, the planetary gear 5 also has a transmission function, but the planetary gear 8
The impact that occurs when the transmission state changes from the independent transmission state to the cooperative transmission state using both planetary gears 5 and 8 is absorbed by the elastic deformation of the spring 10 and the sliding resistance between the gear teeth.

Figures 5 to 8 show examples in which the reduction ratio of the planetary gear reducer is increased so that the input shaft 1 is directly connected to the motor shaft 25 for power steering, and is the same as Figure 3 in the figure. The members with reference numerals are corresponding members.

Small-diameter planetary gears 5' and 8', which mesh with the internal gear 4, are coaxially and integrally connected to the large-diameter planetary gears 5.8, which mesh with the sun gear 2, respectively, in FIG. 5, respectively. Therefore, the collar-shaped support arm B, which is integrated with the output shaft 7, has a ball bearing 22 attached to the input shaft 1.
A flanged auxiliary arm 6' supported by an outer ring of a plurality of parts 2
6 and bolts 27 (Fig. 7),
On the other hand, ball bearings 24, 22 (
There are also a plurality of gaps 28 and bolts 29 between the flanged support arm 9 and the flanged auxiliary arm 9', which are each rotatably supported by the D outer ring.
(Fig. 8) The arm 6.6'
A planetary gear (5, 5') is rotatably supported on a support shaft 11 installed between the arms, and a support shaft 12 installed between the arms 9° and 9'
A planetary gear (8, 8') is rotatably supported on the base plate.

For this reason, the support arm 6.9 is inserted through the shaft 11 so that the support arm 6.9 can freely rotate relative to each other based on the back gaps between the gears 2, 5, 5', 8, 8', and 4. between the through holes 60 of the arms 9 and 9', between the support shaft 12 and the through holes 61 of the arms 6 and 6' that this passes through, or between the space 26 and the through holes 62 of the arms 9 and 9' that this passes through. A required gap is provided between the port 29 and the through hole 66 of the arm 6.6' through which it passes.

The U-shaped target spring 10 has bent portions 10a at both ends thereof.

10b are engaged with the neck portions of the support shafts 11 and 12, respectively, and the central curved portion of the spring is engaged with the outer circumferential surface of the annular base of the support arm B, which is integrated with the output shaft 7. This embodiment is similar to the embodiments shown in FIGS. 3 and 4, and differs only in that the reduction ratio is different. The member designated by the reference numeral 64 in FIG. 0 is an oil seal.

According to the present invention, when switching the rotation direction of the input shaft 10 between forward and reverse directions, there is a possibility that the input shaft rotates with play depending on the back gap of the gear, or even if the input shaft rotates with play, it is possible to prevent the rotation of the input shaft from rotating between the gear teeth. Since it is buffered by mutual sliding resistance and spring elasticity, there is no risk of impact on the rotation operation of the input shaft, and there is also an effect that there is no need to increase the machining accuracy of gears, gear boxes, etc. as in the past.

[Brief explanation of the drawing]

1 and 2 are a plan view and a perspective view, respectively, showing the outline of a steering device for a small transport vehicle, FIG. 3 is a longitudinal sectional front view of an embodiment of the present invention, and FIG. 4 is an enlarged view of the main parts. 5 is a longitudinal sectional front view of another embodiment, FIG. 6 is a sectional view taken along line XX in FIG. 5, and FIGS. 7 and 8 are taken along YY in FIG. 6, respectively.
It is a cross-sectional view corresponding to a cross section and a 2-Z cross section. 16... Handle, 14... Planetary gear reducer, 15
...Steering arm, 16...Tie rod, 17...
Front wheel shaft arm, 18...front wheel.

Claims (2)

[Claims] (1) Sun gear (2) and gear box (
Of a pair of planetary gears that mesh simultaneously with the internal gear (4) fixed to Planetary gear (8
) is fitted so as to be relatively rotatable, and a spring (10) is installed between the support arms (6, 9) to constantly force the support arms (6, 9) to rotate in opposite directions. At least when the input shaft is not driven, the pair of planetary gears (5, 8) maintains a state in which they are in elastic contact with mutually opposite tooth surfaces of the sun gear (2) and the internal gear (4), respectively. A planetary gear reducer characterized by: (2) The spring (10) is configured as a U-shaped bending spring whose center portion engages with the outer peripheral surface of the base of the planetary gear support arm on one side,
Both end bent portions (10a) and (10b) of the U-shaped bending spring
) are respectively engaged with the support shafts (11, 12) of a pair of planetary gears.