JPH1096432A - Torque transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize torque at the initial stage of rotation of a torque limiter using a coil spring and to provide an increased lubrication life. SOLUTION: A coil spring 3 is incorporated between an inner ring 1 and an outer ring 2 rotatably arranged at the outside, and the coil spring 3 is provided with a small coil part 3a to fasten the outside diameter surface of the inner ring 1. One of bent pieces 4 and 5 formed at the two ends of the coil spring 3 is coupled to the outer ring 2, and the other bend piece 5 is coupled to a regulation ring 6 pressed in the opening end part of the outer ring 2. The inner ring 1 is formed of a sintered substance having sintering density of 5.4-6.4g/cm<3> and the infinite number of small holes formed in an internal part are impregnated with a lubricant. Further, through sizing of the inner ring, the opening of the small hole is throttled, a contact part between the inner ring 1 and the small diameter coil part 3a is lubricated by a lubricant with which the surface of the inner ring 1 oozes and initial torque is stabilized. By throttling the opening of the small hole by sizing, an outflow amount of lubrication oil is limited to provide an increase lubrication life.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque transmission device such as a torque limiter and a clutch.

[0002]

2. Description of the Related Art As an example of a torque transmitting device, a torque limiter shown in FIG. 7 will be described.

In this torque limiter, a coil spring 13 is incorporated between an inner ring 11 and an outer ring 12 rotatably provided outside thereof, and a small-diameter coil portion 13a for fastening the outer diameter surface of the inner ring 11 to the coil spring 13 is provided. Adjustment in which one of the bent pieces 14 and 15 formed at both ends of the coil spring 13 is connected to the closed end of the outer ring 12, and the other bent piece 15 is rotatably pressed into the open end of the outer ring 12. It is connected to a ring 16.

In the torque limiter, when the inner ring 11 is rotated in the direction opposite to the winding direction of the coil spring 13 when viewed from the adjustment ring 16 side, the small-diameter coil portion 13a of the coil spring 13 contracts due to contact with the inner ring 11. Diameter, inner ring 11
Tighten. Therefore, the rotational torque of the inner race 11 is transmitted to the outer race 12 via the coil spring 13, and the outer race 12 rotates in the same direction as the inner race 11.

When the load on the outer ring 12 increases and the tightening force for tightening the inner ring 11 by the small diameter coil portion 13a of the coil spring 13 becomes smaller than the frictional force at the contact portion between the small diameter coil portion 13a and the inner ring 11, the inner ring 11 and the small diameter coil portion 13a
And the transmission of rotational torque to the outer race 12 is interrupted.

When the inner race 11 is rotated in the winding direction of the coil spring 13, the small-diameter coil portion 13 a of the coil spring 13 is rotated.
The diameter of the inner ring 11 and the small-diameter coil portion 13a are
And the transmission of rotational torque to the outer race 12 is interrupted.

The torque limiter has a small number of parts, is easy to assemble, has a low manufacturing cost, and
When the adjustment ring 16 is rotated with respect to the outer ring 12, the inner diameter of the small-diameter coil portion 13 a of the coil spring 13 changes and the binding force changes, so that the magnitude of the torque that can be transmitted from the inner ring 11 to the outer ring 12 is adjusted. It has the feature that it can be.

[0008]

In the torque limiter, when the torque transmission is interrupted, the inner ring 11 rotates in contact with the small-diameter coil portion 13a, so that the contact portion between the inner ring 11 and the small-diameter coil portion 13a is worn. Grease lubrication is performed on the contact portion between the inner race 11 and the small-diameter coil portion 13a in order to prevent such abrasion easily. Since the grease is sealed inside the outer ring 12, the grease enters the gap between the small-diameter coil portion 13a and the inner ring 11 irregularly.
The friction coefficient between them changes, and fluctuations and variations in torque are conceivable. Thus, there is a need to improve torque accuracy.

That is, the torque limiter shown in FIG.
Grease is sealed inside the outer ring 12 of each torque limiter, and the inner ring 11 is slid and rotated while the outer ring 12 is stopped, thereby preparing the inner ring 11 (samples No. 1 to No. 8).
When the torque was measured, the test result shown in FIG. 8 (I) was obtained. Here, as the test conditions, the rotation was performed on the inner ring 11 at 483 rpm, the load torque was 300 ± 45 gf · cm, and the test was performed in an operation pattern of 2 seconds operation and 0.2 seconds stop. FIG. 8 (II) shows a graph based on the test results of Samples No. 1 to No. 4, and (III) shows the graph of Sample N.
5 shows graphs based on test results of No. 5 to No. 8.

As is clear from the above test results, the torque limiter in which grease is sealed has large fluctuations in torque and large variations in torque value. It is considered that the cause is that grease enters irregularly between the small-diameter coil portion 13a and the inner ring 11, the friction coefficient between the small-diameter coil portion 13a and the inner ring 11 changes, and the generated torque fluctuates.

As described above, if the generated torque varies, the generated torque becomes unreliable and may not be used.

The above problem occurs not only in the torque limiter but also in a one-way clutch using a coil spring. In other words, in a one-way clutch using a coil spring, the coil spring is wound around the outer diameter surfaces of a shaft fixed hub and a free hub arranged in the axial direction, and the transmission of rotational torque in the same direction as the winding direction of the coil spring is cut off. Then, a rotational torque in the opposite direction is transmitted.

For this reason, when the torque is cut off, the free hub rotates in contact with the coil spring, causing the same wear problem as in the case of the above-described torque limiter. For this reason, grease lubrication is performed, but there is an inconvenience that frequent maintenance is required to supply grease.

Accordingly, the present invention provides a torque transmission device such as a torque limiter or a spring clutch, which has a common property by using a coil spring, thereby improving lubricity to stabilize torque and improve lubrication life. Make it an issue.

[0015]

In order to solve the above-mentioned problems, according to the present invention, an outer ring is rotatably provided outside of an inner ring, and the inner ring is mounted on a coil spring incorporated between the two rings. Adjusting by providing a small-diameter coil portion for tightening the outer diameter surface of the coil spring, connecting one of the bent pieces formed at both ends of the coil spring to the outer ring, and rotatably pressing the other bent piece into the open end of the outer ring. When the inner ring rotates in a certain direction, the inner ring transmits torque to the outer ring via the coil spring when the inner ring rotates in a certain direction, and when a load acting on the outer ring side exceeds a certain level, slippage occurs between the inner ring and the coil spring small diameter portion. Wherein the inner ring is made of a porous sintered body of a metal powder, and the sintered body has a sintered density of 5.4 g / cm ^{3 to} 6.4 g / cm. cm ³
After quenching, the sintered body was degreased to impregnate the small holes of the sintered body with a lubricant, and the openings of the small holes were narrowed by sizing.

The above-described torque transmission device is used as a torque limiter. In use, the lubricant impregnated in the inner ring seeps out to the outer diameter surface of the inner ring to lubricate the contact portion between the inner ring and the small-diameter coil portion. . Therefore, the lubricant is not agitated, and the lubricant is impregnated in the inner ring,
Since the small-diameter coil portion required for lubrication and the inner ring outer diameter surface are easily supplied, stable torque can be generated from the start of operation.

The sintered density of the sintered body is 5.4 g / cm.
^By setting it to ^{3 to} 6.4 g / cm ³ , many small holes can be formed in the inner ring, and many lubricants can be impregnated inside the inner ring.

Further, by sizing the inner ring and narrowing the opening of the small hole, the holding force of the lubricant is increased, and the lubrication life can be improved.

According to a second aspect of the present invention, a shaft fixing hub and a free hub are coaxially arranged in the axial direction, a coil spring is wound around the outer periphery of both the hubs, and one end of the coil spring on the shaft fixing hub side is connected. When the shaft fixed hub rotates in a certain direction, the coil spring is tightened to the free hub to transmit torque to the free hub when the shaft fixed hub rotates in a certain direction. In this case, the free hub has a configuration similar to that of the inner ring.

The above-mentioned torque transmitting device is used as a clutch, and the lubricating action at the time of its use is the same as that of the first aspect of the present invention.

According to a third aspect of the present invention, in the second aspect of the invention, an outwardly projecting end is formed at a free hub side end of the coil spring.
The torque transmission device according to the above, wherein a control claw provided in a control device installed in the vicinity thereof at the time of use is provided so as to be able to advance and retreat on a side that prevents a diameter reduction of the coil spring, thereby controlling torque transmission. It is. In this case as well, it is used as a clutch, but the transmission and cutoff of torque can be freely controlled by the operation of the control device.

[0022]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The first embodiment shown in FIG. 1 is a torque limiter, similar to the conventional example of FIG. 7 described above, and an inner ring 1, an outer ring 2 rotatably provided on the inner ring 1, and both wheels 1, The coil spring 3 has a small-diameter coil portion 3a for tightening the outer diameter surface of the inner ring 1 and a large-diameter coil portion 3b that is not in contact with the two wheels 1, 2. Is provided.

A bent piece 4 is provided at an end of the small-diameter coil portion 3 a, and the bent piece 4 is connected to a closed end of the outer race 2. On the other hand, a bent piece 5 is provided at an end of the large-diameter coil portion 3b, and the bent piece 5 is connected to an adjusting ring 6 rotatably press-fitted into an open end of the outer ring 2.

The inner ring 1 is made of a porous sintered body of metal powder. The sintered density of the sintered body is 5.4 g / cm ^3-
The weight is 6.4 g / cm ^3, and the lubricant is impregnated in the myriad of small holes formed inside. The sintered density of the sintered body is 5.4
If it is less than g / cm ³ , sintering becomes difficult, and
If it exceeds 4 g / cm ³ , the oil content will decrease and oil will run out easily.

Since the inner ring 1 is easily worn by contact with the coil spring 3, it is hardened by carburizing and quenching after sintering. Since the quenching oil has penetrated into the small hole of the inner ring 1 after carburizing and quenching, if the inside of the inner ring 1 after quenching is impregnated with the lubricant, the quenching oil remaining in the small hole causes a large amount of lubricant. Cannot be impregnated.

Therefore, the inner ring 1 is degreased and impregnated oil is removed prior to impregnation.

Incidentally, the sintered density is 6.2 g / cm ³ ,
Two kinds of inner rings of 6.8 g / cm ³ are prepared two by two, and after hardening of each inner ring, the inner ring is degreased with a Soxhlet extractor and then impregnated with a lubricant. The weight of the inner ring before the impregnation and the weight of the inner ring after the impregnation were measured, and the oil content was measured from the difference. As a result, the results shown in Table 1 were obtained.

[0028]

[Table 1]

Further, four inner rings having a sintered density of 6.2 g / cm ³ were prepared. Of these, two inner rings were quenched, degreased, impregnated with a lubricant, and the other two inner rings were cleaned. Impregnation was performed without degreasing, the inner ring weight before impregnation and the inner ring weight after oil impregnation were measured, and the oil content was measured from the difference. As a result, the results shown in Table 2 were obtained.

[0030]

[Table 2]

In each of the measurements, a lubricant prepared by dissolving an additive in a lubricating oil was used.

From the above measurement results, the sintered density was 6.2 g /
It can be understood that when the inner ring of cm ³ is quenched and then degreased and impregnated with a lubricant, the oil content increases.

When the sintering density is low, the diameter of the small hole formed inside the inner ring becomes large, so that a large amount of oil can be retained, but the diameter of the opening of the small hole on the surface of the inner ring also becomes large. Nevertheless, the retained lubricant easily flows out, leading to a reduction in lubrication life or oil leakage.

To eliminate such inconvenience, the inner ring 1 after impregnation is sized, and the sizing narrows the openings of the small holes, thereby suppressing the outflow of the lubricant.

The operation of the torque limiter having the above configuration is the same as the operation of the torque limiter shown in FIG. 7 and will not be described.

As described above, when the inner ring 1 is formed of a sintered body and impregnated with a lubricant, during operation of the torque limiter, the lubricant oozes on the outer diameter surface of the inner ring 1 and the inner ring 1 1 and the contact portion between the small-diameter coil portion 3a is lubricated.

As described above, by lubricating the contact portion between the inner ring 1 and the small-diameter coil portion 3a with the lubricant impregnated in the inner ring 1, the lubricant is not agitated, and the inner ring 1 rotates from the initial rotation. The resistance becomes constant. Further, since the contact between the small diameter coil portion 3a and the inner ring 1 is uniformly lubricated, the friction coefficient between the small diameter coil portion 3a and the inner ring 1 is stabilized, and the torque is stabilized.

Example 1 The sintered density was 6.2 g / cm ³
A sizing inner ring made of a sintered body was formed, the inner ring was carburized and quenched, then degreased, and a lubricating oil was impregnated into the inner ring to form an inner ring (oil material) having an oil content of 0.21 g. . Using this inner ring, eight torque limiters shown in FIG. 1 (samples No. 1 to No. 8) are formed (product of the present invention), and the inner ring 1 is rotated with the outer ring 2 stopped, so that the torque of the inner ring 1 is increased. Was measured, and the result shown in FIG. 2 (I) was obtained.
The measurement conditions were as follows, assuming that the rotation speed of the inner ring 1 was 483 rpm.
The test was performed with a 2.0 second operation and a 0.2 second stop as operation patterns. As is clear from the above results, it can be understood that there is no change in torque from the start of operation and the torque is stable from the beginning of rotation. FIG. 2 (II) shows a graph based on the test results of samples No. 1 to No. 4, and FIG.
(III) shows a graph based on the test results of samples No. 5 to No. 8.

Example 2 The sintered density was 6.8 g / cm ³
An inner ring made of a sintered body of the above is formed, the inner ring is carburized and quenched, then degreased and impregnated with a lubricating oil to have an oil content of 0.12 g
An inner ring was formed. Using this inner ring, a torque limiter shown in FIG. 1 is formed (comparative product). Eight pieces each of this comparative product and the present invention product shown in Example 1 are prepared, and the outer ring 2 is fixed and the inner ring 1 is rotated. Then, when the amount of change in torque after 1000 hours was measured, eight products of the present invention averaged -3.
Compared to 2 gf · cm, the average of eight comparative products was −51 gf · cm 2. The measurement conditions were as follows: the rotation speed of the inner ring 1 was 130 rpm, and the load torque was 340 gf ·
cm, the test was performed with an operation pattern of 2 seconds operation and 0.2 seconds stop. As is clear from the above results, it can be seen that the torque change of the product of the present invention is small.

[Embodiment 3] The torque limiter shown in FIG. 1 was formed using the inner ring obtained by sizing the material shown in Embodiment 1 (product of the present invention). In addition, a sizing inner ring made of a sintered body of 6.2 g / cm ³ is formed, the inner ring is carburized and quenched, and then the interior is impregnated with oil without the degreasing treatment. An inner ring of 09 g was formed, and the torque limiter shown in FIG. 1 was formed using the inner ring (comparative product). Eight each of the product of the present invention and the comparative product were prepared, and the torque change after 1200 hours was measured under the same conditions as in Example 2. As a result, the average of the eight products of the present invention was -39 gf · cm. On the other hand, the average of eight comparative products was -48 gf · cm. From the above, it can be seen that the product of the present invention has a smaller torque change amount than the comparative product.

[Embodiment 4] A sample having the same specifications as in Embodiment 1 and having a torque value adjusted to 340 gf · cm.
An endurance test was performed on o.7 and No.8 under the conditions of operation for 2 seconds and stoppage for 0.5 seconds. FIG. 3 shows the measurement results of the wear state of the contact portion (small diameter side) of the inner ring outer diameter surface with the coil spring and the non-contact portion (large diameter side) of sample No. 7.
(A) to (c), and FIG.
(A) to (c) are shown. FIG. 3A and FIG. 4A show the worn state of the contact portion (small diameter side) and the non-contact portion (large diameter side) of the coil spring. 3 (b) and 4 (b) show a worn state of the inner diameter surface on the small diameter side of the coil spring. FIG. 3 (c), FIG.
(C) shows the state of wear of the large-diameter inner diameter surface of the coil spring.

From these measurement results, it can be seen that no abrasion occurred on the contact rotating surface.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, the present invention is applied to a spring clutch.

In this spring clutch A, a fixed shaft hub 21 and a free hub 22 are coaxially arranged in the axial direction, and a single coil spring 23 is wound around the outer peripheral surfaces of both hubs 21 and 22.

A shaft 24 is passed through the spring clutch A, and a pin 25 fixed to the shaft 24 is
The shaft 24 and the shaft fixing hub 21 can rotate integrally with each other. The free hub 22 is not restricted to the shaft 24 and can rotate freely.

A projection 27 is provided at one end of the free hub 22, and a gear 28 inserted through the shaft 24 is engaged with the projection 27. The gear 28 is inserted in a non-restricted state with respect to the shaft 24, and is prevented from falling off by a stopper 29 fitted to the shaft 24.

It should be noted that a torque transmitting member such as a pulley can be used instead of the gear 28 described above.

The filament of the coil spring 23 has a rectangular cross section and is densely wound with the same diameter in the axial direction. One end of the coil spring 23 on the shaft fixing hub 21 side is
And rotates integrally with the shaft fixing hub 21.

The coil spring 23 is wound several times in close contact with the outer circumferences of the fixed shaft hub 21 and the free hub 22, respectively.
The other end is free on the freehub 22.

In the above-mentioned spring clutch A, the free hub 22 is made of a sintered body of metal powder as in the case of the inner ring 13 of the first embodiment, and the sintered density of the sintered body is 5.4.
a ^{g / cm 3 ~6.4g / cm 3} , is degreased after quenching, any grease or lubricant on the myriad of small holes are impregnated, and in which the opening of the small hole is narrowed down by the sizing .

In addition, the results of various experiments (Tables 1 and 2) performed on the inner ring of the first embodiment and Examples 1 to 4 also apply to the case of the free hub 22.

The spring clutch A according to the second embodiment is as described above. When using the spring clutch A, as shown in FIG. 5, it is used by being combined with a torque transmitting member such as a gear 28 and attached to the shaft 24. .

Assuming that the winding direction of the coil spring 23 is left-handed, when the shaft 24 rotates clockwise as viewed from the shaft fixed hub 21, the coil spring 23 is reduced in diameter and fastened to the outer peripheral surface of the free hub 22. And integrated with the freehub 22. Therefore, the torque of the shaft 24 is transmitted to the gear 28 via the shaft fixed hub 21, the coil spring 23, and the free hub 22.

Contrary to the above, when the shaft 24 rotates counterclockwise, a slip occurs between the coil spring 23 and the freehub 22. Therefore, transmission of torque from the shaft 24 to the gear 28 is interrupted. At this time, the friction in the contact rotating portion between the coil spring 23 and the free hub 22 is reduced by the lubricant impregnated in the free hub 22.

Next, in the spring clutch A of the third embodiment shown in FIGS. 6 (a) and 6 (b), a protruding end 32 which protrudes in the radial direction is formed at the end of the coil spring 23 on the free hub 22 side. . A control claw 33 that is detachable from the protruding end 32
Is provided in a control device (not shown). This control claw 33
Is provided so as to be vertically movable in the radial direction of the free hub 22,
As shown in FIG. 6B, the coil spring 23 can be advanced to a position where the diameter of the coil spring 23 is prevented or can be retracted from the position.

The structure other than the above is the same as that of the above-described second embodiment including the structure of the free hub 22, but in this case, the gear 28 is rotated clockwise as viewed in the axial direction from the right side of FIG. When the diameter of the coil spring 23 is reduced and the coil spring 23 is wound around the outer peripheral surface of the free hub 22 to transmit torque to the shaft 24, if the control claw 33 is advanced to engage with the projecting end 32 of the coil spring 23, Since the diameter of the coil spring 23 does not decrease, transmission of torque is interrupted.

When the gear 28 is rotated in the reverse direction as described above,
Since the diameter of the coil spring 23 does not decrease regardless of the position of the control claw 33, the transmission of torque is cut off.

Although the above description has been made on the case where the torque is transmitted from the gear 28 to the shaft 24, the control claw 33 is also used when transmitting the torque from the shaft 24 to the gear 28.
The torque transmission can be controlled by the forward and backward movement of the motor.

[0059]

As described above, in the torque transmission device such as the torque limiter and the spring clutch according to the present invention,
The members that are in sliding contact with the coil spring, such as the inner ring and the free hub, are formed of a porous sintered body, and the member is impregnated with a lubricant. Can be lubricated. Therefore, wear of the sliding contact surface can be reduced.

[0060] Further, by the sintering density of the member made of a sintered body was set to ^{5.4g / cm 3 ~6.4g / cm 3} , can be impregnated with a lot of lubricant countless small holes Moreover, since the openings of the small holes are narrowed by sizing, the holding force of the impregnated lubricant is improved, and the lubrication life can be improved.

In the case of the torque limiter, the problem of stirring of the lubricant, which has been a problem in the past, is solved, so that the initial torque at the start of operation can be stabilized, and the torque limiter with a small torque change amount can be used. Can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a torque limiter according to a first embodiment.

FIG. 2 (I) is a diagram showing a torque measurement result of an inner ring in the torque limiter of the above, and (II) and (III) are graphs thereof.

3 (a), (b) and (c) show the results of a wear test of sample No. 7. FIG.

4 (a), (b), and (c) show the results of a wear test of sample No. 8. FIG.

FIG. 5 is a sectional view showing a spring clutch according to a second embodiment.

6A is a sectional view showing a spring clutch according to a third embodiment; FIG. 6B is a sectional view taken along line bb in FIG.

FIG. 7 is a sectional view showing a conventional torque limiter.

FIG. 8 (I) is a diagram showing the results of measuring the torque of the inner ring in a conventional torque limiter, and FIGS. 8 (II) and (III) are graphs thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Coil spring 3a Small diameter coil part 4, 5 Bending piece 6 Adjusting ring 21 Shaft fixing hub 22 Free hub 23 Coil spring 24 Axis 25 Pin 26 Concave 27 Projection 28 Gear 29 Stopper 31 Collar 32 Projection end 33 Control claw

Claims (4)

[Claims] 1. An outer ring is rotatably provided outside an inner ring, and a small-diameter coil portion for tightening an outer diameter surface of the inner ring is provided in a coil spring incorporated between the two rings, and a fold formed on both ends of the coil spring. One of the bent pieces is connected to the outer ring, and the other bent piece is connected to an adjustment ring rotatably press-fitted into the open end of the outer ring, and is connected to the outer ring via the coil spring when the inner ring rotates in a certain direction. A torque transmitting device that transmits torque and causes a slip between the inner ring and the coil spring small-diameter portion to cut off the transmission of torque when the load acting on the outer ring side is equal to or greater than a certain value. It consists of a porous sintered body, and the sintered density of the sintered body is 5.4 g.
/ Cm ^{3 to} 6.4 g / cm ³ , after quenching, degreased and impregnated with a lubricant in small holes of the sintered body, and the openings of the small holes are narrowed by sizing. Torque transmission device. 2. A shaft fixing hub and a free hub are coaxially arranged in the axial direction, a coil spring is wound around the outer periphery of both the hubs, and one end of the coil spring on the shaft fixing hub side is connected to the shaft fixing hub. When the shaft fixed hub rotates in a certain direction, the coil spring is tightened to the free hub to transmit torque to the free hub, and when the shaft fixed hub rotates in a direction opposite to the above, a slip is generated between the coil spring and the free hub to cause torque. In the torque transmission device for interrupting the transmission of heat, the free hub is formed of a porous sintered body obtained by sintering a metal powder, and the sintered body has a sintered density of 5.4 g / cm ^{3 to} 6.
4 g / cm ^3, which is degreased after quenching, impregnated with a lubricant in small holes of the sintered body, and the openings of the small holes are narrowed by sizing. 3. The torque transmitting device according to claim 2, wherein a protruding end protruding outward is formed at a free hub side end of said coil spring, and is provided in a control device installed near the time of use. A torque transmission device in which a control claw is provided on a side that prevents the diameter of the coil spring from moving forward and backward so as to control torque transmission. 4. The torque transmission device according to claim 1, wherein the lubricant is one of grease and lubricating oil.