FR2512512A1 - TORQUE LIMITER FOR PLANETARY REDUCTION GEAR - Google Patents

Abstract

A. TORQUE LIMITER FOR PLANETARY REDUCTION GEAR. B. TORQUE LIMITER CHARACTERIZED IN THAT IT USES A LOCK RELEASE MECHANISM 23 INTENDED TO UNLOCK ANNULAR GEAR 11 TO THUS CUT THE TRANSMISSION OF POWER BETWEEN INPUT SHAFT 10 AND OUTPUT SHAFT 16 WHEN A ROTATION TORQUE GREATER THAN A PREDETERMINED VALUE IS EXERCISED ON THE ANNULAR GEAR 11. C. THE INVENTION APPLIES IN PARTICULAR TO A MOTOR TILLER STEERING WHILE WALKING.

Description

The invention relates to a torque limiter for

  planetary reduction gear.

  In a small walk-behind type tiller, a planetary reduction gear is connected directly to the crankshaft of an engine, so as to reduce the speed considerably. The mobile work device can thus train by means of a mechanism. relatively compact.

  In such a structure, if a shock or an over-

  load are transmitted by the wheels or by the engine, at the crankshaft of the engine, there is a danger of stalling the engine

  or damage internal gears or transmission shafts.

  mission, when such an overload is applied abruptly.

  The invention aims to overcome these drawbacks.

  by creating a torque limiter for reduction gears.

  planetary system, able to avoid the above risks.

  To this end, the invention relates to a torque limiter for planetary reduction gear comprising an input shaft on which is mounted a sun gear, a fixed annular gear, planetary gears meshing with the sun gear and with the sun gear. fixed annular gear, a movable member rotatably supporting the planet gears, and an output shaft connected to the movable member, limiter of

  characterized in that it uses a release mechanism

  locking mechanism for unlocking the annular gear

  to cut power transmission between

  the input shaft and the output shaft when a rotating torque

  above a predetermined value is exerted on the

ring graining.

  According to the invention, the annular gearing is

  stationary mechanism of the planetary gear reduction mechanism

  the fixed annular gear is constructed of such

  that when it is shocked or overloaded, that engender

  fixed swimming can start to rotate by suppressing the transmission

  of power, which thus constitutes a torque limiter.

  High efficiency of operation can be achieved

  with improvements and improvements

simple to an existing structure.

  The invention will be described in detail by means of the accompanying drawings in which:

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  FIG. 1 is a general side view of a walk-behind type tiller, on which there is shown

  mounted a torque limiter for a reduction gear with

  according to the invention; Fig. 2 is a vertical section of the essential parts of the planetary reduction gear torque limiter according to Fig. 1; Figure 3 is a sectional view along the line III-III of Figure 2; and FIG. 4 is a perspective view of a

  lock release mechanism.

  FIG. 1 represents a walking tiller whose machine body comprises a motor 1, a transmission boot 2 mounted under the engine 1 by means of a planetary-type transmission gear (hereinafter referred to as a reduction gear planetary), a bumper 3 and a fender 4 The tiller further comprises a guide sleeve 5 from the lower part of the body of the machine, crop rotors 5 rotatably mounted on both

  lateral sides of the lower part of the transmission boot.

  2, and a strut 7 removably attached to the base of the handle 5 This walking tiller can thus operate by rotating the crop rotors 6 while moving

the machine body.

  The following description concerns the structure of the

  transmission mechanism of the engine output power

with rotors 6.

  As shown in Figures 2 and 3, three engra-

  planetary gears 9 of the planetary reduction mechanism 8, are engaged with a sun gear 10 'integral with the end of the input shaft or crank shaft 10 of the motor 1 An annular gear 11 surrounds the three gears

  planetary 9 and comes into engagement with them.

  The annular gear 11 is provided on its

  four-cavity outer tower 12 A 13-ball is pushed

  in place in each of these cavities 12 by a spring 14 sup-

  carried by the transmission boot 2, so that the gear

  ring 11 is fixed integrally from the truss of

mission 2.

  The springs 14 have a predetermined pushing force

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  When a large rotational torque is exerted on the annular gear 11, the springs 14 are compressed by the balls 13 that are thus released from the cavities 12.

  in this way a locking release mechanism 23.

  A movable member 15 rotates the three planetary gears 9 and takes into account, in the form of output power, the rotation of the planetary gears 9 around the sun gear 10. The movable member 15 comprises at its center a cylindrical portion. 15 provided with holes for

  15 b beads in which are housed balls 15 c.

  An output shaft or transmission shaft

  mediator-16 is mounted concentrically and end to end

  port to the input shaft 10 In the vicinity of the keyed end

  of the output shaft 16 are cavities 16a in the-

  which are housed the marbles 15 c.

  A clutch actuating member 17 is slidably mounted on the cylindrical portion 15a A pressure spring 18 is mounted between the clutch actuating member

  17 and a portion of the movable member 15.

  The clutch actuating member 17 has internal cavities 17a into which the balls can be housed, and ball retaining portions 17b normally holding the balls 15c in the ball holes.

b and in the cavities 16 a.

  As a result, when the clutch actuating member 17 slides against the spring 18, the cavities 17a move towards the position of the balls 15c to allow them to penetrate into the cavities 17a, thus cutting the connection between the tree

  intermediate transmission 16 and the movable element 15.

  The intermediate transmission shaft 16 comprises at its other end a threaded hole in which is screwed one end of a transmission shaft 19 at the other end.

  which attaches a bevel gear 20.

  An axle 21 is rotatably mounted at the end

  lower part of the transmission boot 2 and comprises a gear

  conical swim 22 engaged with the bevel gear 20 As shown in FIG. 1, the rotors 6 are mounted on the axle 21.

  In the transmission boot 2, the upper part

  2 intended to house the annular gear 11 present

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  a larger diameter, and the lower portion 2b for housing the output shaft 16 has a smaller diameter, so that the transmission box 2 has a funnel-shaped section The clutch device comprising the balls 15 c is then actually housed in the large space of the upper part of the gearbox shaped

funnel 2.

  When an overload is applied to the rotors 6 during operation of the tiller, this overload is transmitted directly to the movable member 15 which transmits this overload as a pulse to the annular gear 11 in engagement with the planet gears 9 carried by the element

mobile 15.

  However, when a large rotational torque is exerted on the annular gear 11, the spokes 14 are compressed by the balls 13 to allow these balls to

  release 12-in cavities thus freeing the lock.

  the annular gear 11 Thus, the material connection between the output shaft 10 and the intermediate transmission shaft 16 is released, which allows to obtain the function of

torque limiter.

  When the overload disappears from the side of the rotors 16, we find ourselves in a situation where the balls 13 return to lodge in the cavities 12 after the ring gear

  has performed a predetermined number of turns.

  It should be noted that the rotors 6 can be

  by ordinary wheels, the invention being

  apply well to any transmission system.

  As a locking release mechanism 23, any mechanism having the same function, such as a so-called disc brake type mechanism, in which the annular gear 11 is sandwiched from the two can be used.

c 8 tees.

2 S 125 1 2

Claims (2)

CLAIMS) Planetary gear reduction torque limiter comprising an input shaft (10) on which a sun gear (10 '), a fixed annular gear (11), meshing planetary gears (9) are mounted with the sun gear (10 ') and with the fixed annular gear (11), a movable member (15) rotatably supporting the planet gears (9), and an output shaft connected to the movable member ( 15), a torque limiter characterized in that it uses a locking release mechanism (23) for unlocking the annular gear (11) to thereby cut the power transmission between the input shaft (10) and the output shaft (16) when a torque greater than a predetermined value is exerted on the annular gear (11).   2) torque limiter according to claim 1, characterized in that the locking release mechanism (23) comprises at least one cavity (12) formed in the periphery of the annular gear (11), at least one ball (13). ) being received in this cavity (12), and at least one spring (14) for pushing the ball (13), the structure being such that the annular gear (11) starts to rotate when the ball   (13) is released from the cavity (12).   ) Torque limiter according to any one of   Claims 1 and 2, characterized in that the input shaft   (11) is constituted by the output shaft of an engine (1), and that the output shaft (16) is connected via a gear transmission mechanism to an axle ( 21)   on which are mounted wheels or crop rotors (6).   ) Torque limiter according to any one of   Claims 1 to 3, characterized in that between the element   mobile (15) and the output shaft (16) is located a clutch device comprising a cylindrical portion (15a) integral with the movable member (15), balls (15c), cavities (17) a) in which are housed the balls (15 c),   ball retaining portions (17b) and a pressure spring (18).   ) Torque limiter according to any one of   Claims 1 to 4, characterized in that it further comprises   a gearbox (2) for housing the ring gear (11), the lock release mechanism (23),   the ball (13) and the output shaft (16), this transmission box 6 2512512   mission (2) consisting of a top box part   (2 a) of larger diameter, intended to house the annular gear   and a smaller diameter lower box portion (2b) for accommodating the output shaft (16), the transmission box (2) thus having a funnel-shaped section.