JPH0452491Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a ball-removable torque limiter that is used in various power transmission systems to prevent damage to equipment due to overload. It is something.

[Conventional technology] Conventional ball removable torque limiters include:
For example, there is one shown in FIG. That is, this torque limiter has a pair of relative rotation elements a and b that are fitted for relative rotation with their axes aligned, and an end face c of one relative rotation element a that is perpendicular to the axis. an engaging recess d, a ball holding hole e provided through a portion of the other relative rotation element b corresponding to the engaging recess d, and a ball holding hole e that is accommodated in the ball holding hole e and is movable in the direction of the engaging recess d. A ball f, a slide g positioned behind the ball f and externally fitted onto the one relative rotation element a so as to be slidable in the axial direction, and a slide g held on the front end surface of the slider g and attached to the ball f. The ball f is accommodated in a holding hole i provided at the rear end of the slider g, and its extension force urges the slider g forward to cause the ball f to be elastically engaged with the engagement recess d. It is equipped with a coil spring j.

[Problems to be solved by the invention] However, in the case of using the coil spring i as described above, the spring itself is bulky and it is difficult to exert a strong urging force. It is not suitable for use as an aircraft-mounted torque limiter, etc., which is small and lightweight and requires high release torque. Furthermore, in the conventional slider g, the slider g serves both as a bearing holder that holds the thrust bearing h and as a spring holder that holds the bulky coil spring j.
This slider g has to be large. Therefore, a torque greater than the set value acts between the two relative rotation elements a and b, and these two elements a and b
When the ball f starts relative rotation, in other words, when the ball f disengages from the engagement recess d and repeats the action of falling back into the adjacent engagement recess d, the aforementioned large slider g violently rotates in the axial direction. advance and retreat. Therefore, there is a problem that the frictional sliding area at the time of release is large, and the release torque is likely to decrease due to aging due to wear.

In addition, since the slider g is rotatable in this device, the slider g is likely to be displaced in the rotational direction at the time of release as described above. Therefore, the coil spring i held by the slider g may be twisted and the biasing force of the spring i may change, causing instability in that the release setting torque fluctuates. Moreover, in the conventional one, the other relative rotation element b having the ball holding hole e is rotatably fitted to the outer periphery of one relative rotation element a having the engagement recess d via a bearing bush. On the outer periphery of this relative rotation element b,
A slider g is fitted so as to be slidable and rotatable. Therefore, only a degree of freedom is allowed between the relative rotation elements a and b for relative rotation around a common axis. Therefore, the so-called degree of freedom in assembling the relatively rotating elements a and b in a required power transmission system is low, and high dimensional accuracy is required for the parts to be assembled.

For example, as shown in Japanese Patent Publication No. 55-21895, it is possible to deal with such problems by adjusting the relative rotational element of one relative rotational element to the other relative rotational element within a certain range. There is one that allows you to shake your head. That is, this device has a first relative rotation element mounted on the outer periphery of the vertical rotation shaft, and a plurality of engagement recesses that are loosely fitted around the outer periphery of the rotation shaft and have a partially cylindrical shape on the inner periphery. and a downward cup-shaped second relative rotation element. and a portion of the first relative rotation element located within the second relative rotation element,
A ball holder having a plurality of ball holding grooves open downward is integrally provided, and each ball holding groove holds a ball that can be engaged with the engagement recess so as to be retractable in the radial direction. Each ball is
The tapered thrust ring is in rolling contact with the tapered surface facing diagonally upward, and by elastically biasing the tapered thrust ring upward with a spring, the outer end portion of each ball is connected to the second relative. It is adapted to be engaged with an engagement recess provided on the inner periphery of the rotating element.

With such a configuration, power is normally transmitted between the two relatively rotating elements via the plurality of balls, but if the transmitted torque exceeds the preset release torque, each The ball moves inward while pushing down the tapered thrust ring against the biasing force of the spring, and is disengaged from the engagement recess.

However, with this configuration, the ball is pushed into the engagement recess only by a portion of the spring's pressing force, that is, by the horizontal component force on the tapered surface of the tapered thrust ring. There is a problem in that setting a high release torque requires a large spring force. In addition, the vertical force on the tapered surface acts as a force that constantly presses each ball against the ceiling surface of the ball holding groove, so the ceiling surface is likely to wear out and the set release torque will change over time. . Moreover, such a device has the disadvantage that the number of parts increases because it is necessary to change the direction of the pressing force midway through, and if the height position of the ceiling surface of the ball holding groove is not constant, each ball A large difference occurs in the outward biasing force, making it impossible to obtain the desired release torque. Therefore, high precision is required in parts processing.

In addition, in such a configuration, since the engagement recesses have a groove shape that extends vertically, the second relative rotation element is moved from the first relative rotation element to the extent that each ball does not come off from the engagement recesses. Although it is possible to perform a swinging motion with respect to the relative rotation element, and the degree of freedom of assembly can be ensured, the most serious problem occurs in this case. That is, in such a device, when the second relative rotation element is tilted, the first
The distance between the axis of the relative rotation element and each ball changes, and the release torque changes unduly. Therefore, a problem arises in that performance stability is impaired even though the degree of freedom in assembly is improved.

The present invention aims to reliably solve such problems.

[Means for solving the problem] In order to achieve the above purpose, the present invention
A pair of relative rotation elements loosely fitted to each other so that their axes coincide with each other so that they can rotate relative to each other, an engagement recess opened in an end surface perpendicular to the axis of one of the relative rotation elements, and the other relative rotation element. a ball holding hole penetrating through a portion of the rotating element corresponding to the engagement recess; a ball accommodated in the ball holding hole and capable of advancing and retreating in the direction of the engagement recess; A spring holder fixed to a relative rotation element, a disc spring held by the spring holder, and a biasing force of the disc spring slidably interposed between the disc spring and the ball are transmitted through a thrust bearing. and a bearing that transmits the force to the ball and causes the ball to be elastically engaged with the engagement recess. The relative rotation element having the ball holding hole, the spring holder, and the bearing holder are each made separate, and the spring holder and the bearing holder allow the relative rotation element having the ball holding hole to freely move. It is characterized by its structure so as not to interfere with the

[Operation] With such a configuration, torque is transmitted from one relative rotation element to the other relative rotation element via the ball, for example. At this time, the biasing force of the disc spring is transmitted to the ball via the bearing holder and the thrust bearing, and the biasing force maintains the state of elastic engagement with the engagement recess. At the time of overload, the ball overcomes the biasing force of the disc spring, separates from the engagement recess, rolls on the end face, and repeats attachment and detachment to and from the engagement recess. Then, when the overload is released, the ball seats in the engagement recess again, and synchronous transmission of torque between the two relative rotation elements is resumed.

However, in this torque limiter, the bearing holder and the spring holder are separated, and a disc spring is used instead of a coil spring, and this disc spring is held by a spring holder fixed to one of the relative rotation elements, so that when the release occurs, , only the bearing holder moves forward and backward as the ball is attached and detached, and the disc spring repeats expansion and contraction without almost any movement, that is, without twisting or positional deviation. Furthermore, in this device, both the relative rotation elements are loosely fitted into each other, and the spring holder and the bearing holder are configured so as not to impede the free movement of the relative rotation element having the ball holding hole. The relative rotation element can freely move relative to the first relative rotation element by an amount corresponding to the clearance between the ball holding hole and the ball. Therefore, the degree of freedom in assembly can be increased compared to the conventional device shown in FIG.

Furthermore, according to the configuration of the present invention, since the degree of freedom of assembly is improved, the various problems mentioned above such as a complicated structure and fluctuations in release torque that lead to unstable performance do not occur. . That is, according to the configuration of the present invention, the direction of the force of the disc spring pressing the bearing holder and the direction of the force of the bearing holder pressing the ball toward the engagement recess via the bearing are the same, so that the disc spring All of the spring force caused by this will effectively act as a force for engaging the ball with the engaging recess. Therefore, compared to the tapered thrust ring described above, it is possible to obtain a large release torque with a smaller spring force, and there is no need for any parts to change the direction of the force, simplifying the structure. can be achieved. In addition, since the ball is not strongly pressed by spring force against surfaces other than the engagement recess, there is no problem that the preset release torque changes over time due to wear on the surface against which the ball is pressed. . Furthermore, the most important effect is that even if the relative rotation element with the ball holding hole moves freely using the clearance between the ball and the ball holding hole, the disc spring will
There is no change in the state in which the ball is pressed through the bearing holder and the bearing and elastically engaged with the engagement recess. Therefore, even if the degree of freedom in mounting is improved by loosely fitting the two relative rotation elements into each other, unexpected fluctuations in release torque will not occur.

[Example] Hereinafter, an example of the present invention will be described with reference to FIG.

FIG. 1 is a longitudinal sectional view showing a torque limiter according to the present invention, in which numeral 1 represents a shaft as one relative rotation element, and numeral 2 represents a ball holder as the other relative rotation element. The shaft 1 has a flange 3 at an intermediate portion, and the ball holder 2 has an axis n at a portion of the shaft 1 adjacent to the flange 3.
They are matched and fitted rotatably. The end surface 4 of the flange 3 is a plane perpendicular to the axis n, and a plurality of tapered hole-shaped engagement recesses 5 are opened at predetermined intervals in the circumferential direction. . Ball holding holes 6 are formed through the ball holder 2 at portions corresponding to the respective engaging recesses 5, and balls 7 are accommodated in these ball holding holes 6 so as to be movable in the direction of the engaging recesses 5. are doing. In other words, each ball 7 is accommodated in each ball holding hole 6 with a clearance sufficient to allow it to freely move forward and backward. Further, a spring holder 8 is fixed to the outer periphery of the shaft 1 so as to be located behind these balls 7. The spring holder 8 is a cylindrical body having a locking collar 9 at its rear end, and is non-rotatably fitted to the outer periphery of the shaft 1 via a key 11.
It is pressed and fixed to the stepped end face 14 of the shaft 1 by a nut 13 screwed into the rear end threaded part 12. A bearing holder 15 is fitted onto the outer periphery of the front end of the spring holder 8 so as to be movable in the axial direction, and the spring holder 8
A plurality of disk springs 17 are wound around the spring holder 8 and are interposed between the locking collar 9 and the bearing holder 15. The bearing holder 15 is
It is disc-shaped with a concave portion 18 on its front end surface, and the thrust bearing 19 is held in the concave portion 18 . Note that 21 is a plate attached to the ball 7, and 22 is a ring retainer. Also, 2
3 is the spring holder 8 and the step end surface 1;
This is a shim interposed between 4 and 4. By selecting the number of shims 23, the force with which the disc spring 17 urges the ball 7 toward the engagement recess 5 can be adjusted.

The torque limiter of this embodiment is intended to be incorporated into the gear train of a gearbox, and is used by attaching gears (not shown) to the keyway 24 portion of the shaft 1 and the outer spline 25 portion of the ball holder 2. .

With such a configuration, the bearing holder 15 is biased forward by the disc spring 17, and the biasing force is transmitted to each ball 7 via the thrust bearing 19. The balls 7 are elastically engaged with the corresponding engagement recesses 5 (see imaginary lines), and the shaft 1 and ball holder 2 maintain a state in which they can rotate together.
In this state, when the torque acting between the shaft 1 and the ball holder 2 exceeds a preset release torque due to overload, each of the balls 7 separates from each of the engagement recesses 5 and the end surface 4
The shaft 1 and the ball holder 2 can rotate relative to each other. Then, while the overload condition is not improved, the ball 7
The operation of coming off from the engagement recess 5, climbing onto the end face 4, rolling on the end face 4, and falling into the adjacent engagement recess 5 is repeated. At this time, the bearing holder 15 moves forward and backward in response to the attachment and detachment of the ball 7 to and from the engagement recess 5, causing the disc spring 17 to expand and contract.

In this way, it functions as a torque limiter, and since this device uses a disc spring 17 as a spring to elastically engage the ball 7 with the engagement recess 5, it is better to use a coil spring. It is possible to obtain a much stronger ball biasing force compared to the conventional method. Therefore, it is possible to obtain high release torque with a small and lightweight device. Moreover, since the bearing holder 15 and the spring holder 8 are completely separated and the spring holder 8 is fixed to the shaft 1, the entire disc spring 17 does not swing or twist when released. , frictional sliding parts can be significantly reduced. That is, the spring holder 8 fixing the disc spring 17 to the shaft 1
If the bearing holder 15 is held in the same position, at the time of release, only the relatively small bearing holder 15 will move forward and backward as the ball 7 is attached and detached, and the disk spring 17 will only repeatedly expand and contract without moving much. Therefore, changes in spring force and occurrence of wear in frictional sliding parts are significantly reduced, making it possible to stabilize and maintain release torque over a long period of time. Moreover, as clearly shown in FIG. 1, the ball holder 2 is loosely fitted onto the shaft 1, and the spring holder 8 and bearing holder 15 are configured so that they do not interfere with the free movement of the ball holder 2. Therefore, the ball holder 2 can be freely fitted into the shaft 1 by an amount corresponding to the clearance between the ball holding hole 6 and the ball 7. Therefore, the degree of freedom in assembly can be increased compared to the conventional device shown in FIG.

Moreover, according to this configuration, since the degree of freedom of assembly is improved, the various disadvantages mentioned above, such as a complicated structure and fluctuations in release torque that lead to unstable performance, do not occur. That is, according to this configuration, the direction of the force with which the disc spring 17 presses the bearing holder 15 and the bearing holder 1
5 presses the ball 7 toward the engagement recess 5 through the bearing 19 in the same direction, so all the spring force from the disc spring 17 is applied to the ball 7.
This effectively acts as a force for engaging the engagement recess 5 with the engagement recess 5 . Therefore, compared to the tapered thrust ring described above, it is possible to obtain a large release torque with a smaller spring force, and there is no need for any parts to change the direction of the force, simplifying the structure. can be achieved. Furthermore, since the ball 7 is never strongly pressed against any surface other than the engagement recess 5 due to the biasing force of the disc spring 17, the preset release torque changes over time due to wear of the surface against which the ball is pressed. This problem does not occur. Furthermore, even if the ball holder 2 moves freely using the clearance between the ball 7 and the ball holding hole 6, the disc spring 17
However, the bearing holder 15 and the bearing 19
There is no change in the state in which the ball 7 is pressed and elastically engaged with the engagement recess 5 via the ball 7.
Therefore, even if the shaft 1 and the ball holder 2 are fitted loosely into each other to improve the degree of freedom of attachment, unexpected fluctuations in the release torque will not occur.

In addition, in the above embodiment, the case where one of the relative rotation elements is a shaft has been explained, but it goes without saying that the present invention is not necessarily limited to such a thing, and the embodiment of the transmission system etc. to be incorporated can be changed. Various modifications are possible depending on the situation.

In addition, the torque may be transmitted by using either of the relative rotation elements on the input side or the output side, and the rotation direction is not limited. It is also applicable to the case where any relative rotation element is fixed.

[Effects of the invention] As described in detail above, in the present invention, the ball is biased by a disc spring to elastically engage with the engagement recess, so that it is possible to achieve a reduction in size and weight, and It is possible to set the release torque to a high value. Moreover, since the bearing holder and the spring holder are completely separated and the spring holder is fixed to the shaft, the entire disc spring does not swing or twist when released, and the spring holder does not swing or twist when released. The parts to be used can be limited to only small bearing retainers. Therefore, compared to the conventional slider in which a large slider that serves as both a bearing holder and a spring holder slides, the frictional sliding area can be reasonably and significantly reduced, and fluctuations in the ball urging force due to spring torsion can be eliminated. I can do it. Therefore, it is possible to provide an excellent torque limiter that can maintain stable release torque over a long period of time. Further, in the present invention, both the relative rotation elements are loosely fitted into each other, and the spring holder and the bearing holder are configured so as not to impede the free movement of the relative rotation element having the ball holding hole. The degree of freedom in assembly can be increased compared to the conventional device shown in FIG. Furthermore, as described above, the present invention maintains the structure in which the ball is elastically engaged with the engagement recess without changing the direction of the spring force, while allowing free movement of both relative rotation elements. Because of this structure, the degree of freedom in assembly is improved, and problems such as a complicated structure and fluctuations in release torque that lead to unstable performance can be resolved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, and FIG. 2 is a half-mounted sectional view showing a conventional example. n...Axis center, 1...Relative rotating element (shaft),
2... Relative rotating element (ball holder), 4... End face, 5... Engaging recess, 7... Ball, 8... Spring holder, 15... Bearing holder, 17
... Disc spring, 19 ... Thrust bearing.

Claims (1)

[Scope of utility model registration request] a pair of relative rotation elements that are loosely fitted to each other so that their axes coincide with each other so that they can rotate relative to each other; and a tapered hole-shaped engagement recess that is opened in an end surface perpendicular to the axis of one of the relative rotation elements. , a ball holding hole penetrating through a portion of the other relative rotation element corresponding to the tapered hole-shaped engagement recess, and a ball accommodated in the ball holding hole and movable in the direction of the tapered hole-shaped engagement recess. , a spring holder positioned behind the ball and fixed to the one relative rotation element, a disc spring held by the spring holder, and a disc spring slidably interposed between the disc spring and the ball. and a bearing holder that transmits the biasing force of the disc spring to the ball via a thrust bearing to elastically engage the ball in the engagement recess, the thrust bearing being aligned with the axis. A removable ball torque limiter characterized in that the biasing force of the disc spring is transmitted to the ball via a vertically arranged flat plate.