JPH0674250A - Power transmission with overload safety device - Google Patents

Abstract

PURPOSE:To provide a PTO power transmission with an overload safety device not liable to be degraded due to abrasion or the like nor liable to change in the overload action value. CONSTITUTION:A PTO power transmission has an output gear 11 meshed with an input gear 12, an output shaft 52, and a hub boss 51 interposed between the output gear 11 and the output shaft 52. This power transmission further has an engaging ball 41 inserted in the ball hole 111 of the output gear 11, a relay ring 42 for pressing the engaging ball 41 to the engaging groove 511 of the hub boss 51, lock mechanism 2 for stopping the pressing action of the relay ring 42 at the overload time, and a reset lever 30 for rotating the output gear 11 reversely so as to release the lock of the lock mechanism 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTO (power take-off) power transmission device with an overload safety device used for driving a winch or the like.

[0002]

2. Description of the Related Art A PTO power transmission device for driving a winch or the like is provided with a safety device that responds to an overload. The safety device stops the transmission of power from the drive shaft side to the driven shaft side when the load torque exceeds a predetermined limit value, and automatically stops the power transmission when the load torque falls below the above limit value. It is to restart the transmission.

For example, as shown in FIG. 10, the PTO power transmission device 1 transfers the power of the output gear 14 of the transfer to
Drive shaft 54 through output shaft 52
Is configured to communicate. Drive shaft 5
4 is connected to the output shaft 52 via a universal joint 53. The output shaft 52 is spline-coupled to the hub boss 51.

On the other hand, the output gear 14 of the transfer is connected to the output gear 11 via an input gear 12 which can be engaged and disengaged. The output gear 11 is provided with a ball hole 111 that accommodates the engagement ball 41. Further, the hub boss 51 is provided with an engaging groove 511 for engaging with the engaging ball 41 on its right side surface 513. As shown in FIG. 11, a plurality of ball holes 111 and engagement grooves 511 are arranged at positions asymmetric with respect to the axis.

On the other hand, a relay ring 42 is provided on the outer periphery of the hub boss 51. The relay ring 42 receives the biasing force of the coil spring 431, and the engaging ball 41
Is pressed into the engaging groove 511. The coil spring 431 is a stopper 4 fixed to the hub boss 51.
4 and the relay ring 42. In FIG. 10, reference numeral 81 is a PTO case, reference numeral 1
3 is an input shaft, 112 is a needle bearing, and 441 is a snap ring.

In a steady state, the power of the output gear 11 is transmitted to the hub boss 51 by the engaging force between the engaging ball 41 and the engaging groove 511 due to the pressing force of the relay ring 42. Then, the hub boss 51 rotates and drives the drive shaft 54 via the output shaft 52. The load torque connected to the drive shaft 54 has a predetermined value T _0.
The engaging ball 41, the coil spring 431
The relay ring 42 is pushed back against the pressing force of, and the engagement between the engagement ball 41 and the engagement groove 511 is released. Then, the output gear 11 idles and the hub boss 51 stops rotating.

The load on the drive shaft 54 is a predetermined value T _0.
When it returns to the inside, the engagement ball 41 and the engagement groove 511 are engaged again, and the power transmission is restarted. As described above, the PTO power transmission device transmits power while stopping power transmission during overload.

[0008]

However, the conventional apparatus has the following problems. As mentioned above, when overloaded,
The rotation of the hub boss 51 is stopped and the output gear 11 idles. At this time, the engagement ball 41 rotating integrally with the output gear 11 receives the pressing force of the relay ring 42 and rotates while pressing the right side surface 513 of the hub boss 51. Then, the engagement ball 41 intermittently sinks into the engagement groove 511 and collides with the edge portion of the engagement groove 511. Therefore, a shocking repeated load is generated between the engagement ball 41 and the engagement groove 511, and the engagement ball 41 and the engagement groove 511 are generated.
Wears out.

The coil spring 43 receives the pulsating reaction force and repeats expansion and contraction. Therefore, coil spring 4
The bias of 3 diminishes. The decrease in the biasing force of the coil spring 431 results in a decrease in the overload set value T ₀ . Therefore, the power transmission is frequently stopped, and the power transmission function of the PTO is deteriorated. In view of the problems of the conventional device, the present invention is provided with an overload safety device that is less likely to cause deterioration such as wear in the coupling portion for torque transmission and that does not change the operating value of the overload safety operation over time. PTO
It is intended to provide a power transmission device.

[0010]

The present invention is a PTO power transmission device having an output gear meshed with an input gear, an output shaft, and a hub boss interposed between the output gear and the output gear. The engaging ball inserted into the ball hole of the tooth gear, the relay ring that presses the engaging ball into the engaging groove of the hub boss, the stopper fixed to the hub boss, and the interposing between the stopper and the relay ring. And a lock mechanism that locks the pressing action of the relay ring and stops the pressing force on the engaging ball when the load is overloaded, and an elastic material that applies a pressing force to the relay ring. P with an overload safety device, characterized by having a return lever for releasing the locking action of the locking mechanism by rotating.
It is in the TO power transmission device.

The most notable point in the present invention is the provision of a lock mechanism that operates so as to stop the pressing action of the relay ring on the engaging balls when overloaded. Further, a return lever is provided which operates so as to release the operation (lock operation) of stopping the pressing force of the relay ring by the lock mechanism. The return lever does not operate when the output gear normally rotates, and releases the locking operation only when the output gear reversely rotates.

[0012]

In the power transmission device of the present invention, when the load torque on the hub boss is within the predetermined value T ₀ , the power of the output gear is generated between the engagement ball and the engagement groove as in the conventional example. It is transmitted to the hub boss by the engaging force and is output to the drive shaft via the output shaft. On the other hand, at the time of overload, the lock mechanism operates and locks the relay ring, so that the pressing action of the relay ring on the engaging ball is stopped. Therefore, the output gear rotates without the engaging ball pressing the side surface of the hub boss.

Therefore, the engaging ball will not sink into the engaging groove of the hub boss and repeatedly collide. Therefore, the engagement ball and the engagement groove are not worn. Further, the coil spring does not repeat the above-mentioned intermittent expansion and contraction when overloaded. Therefore, the biasing force of the coil spring does not decline as early as in the conventional device.

When the output gear is rotated in the reverse direction, the return lever operates to release the lock operation of the lock mechanism. Then, the engaging ball receives the pressing force from the relay ring again, engages with the engaging groove, and the hub boss receives the rotational force. If the load torque T is less than or equal to the predetermined value T ₀ , the hub boss rotates as it is, and if it is overloaded (T> T ₀ ), the lock mechanism operates again. Others are the same as the conventional example.
As described above, according to the present invention, the PTO power with overload safety device, which is less likely to cause deterioration such as wear in the coupling portion for torque transmission, and which does not change the operating value of the overload safety operation over time. A transmission device can be provided.

[0015]

Embodiments of the present invention will be described with reference to FIGS. In this example, as shown in FIG.
The PTO power transmission device 1 includes an output gear 11 meshed with the gear 2, an output shaft 52, and a hub boss 51 provided between the output shaft 52 and the output shaft 52. The power transmission device 1 includes an engagement ball 41 inserted into the ball hole 111 of the output gear 11 and a relay ring 4 for pressing the engagement ball 41 into the engagement groove 511 of the hub boss 51.
2, a stopper 44 fixed to the hub boss 51, and an elastic member 43 provided between the stopper and the relay ring 42 to apply a pressing force to the relay ring 42.

Further, at the time of overload, the relay ring 42
It has a lock mechanism 2 that locks the pressing action of (1) and stops the pressing force on the engaging ball 41. Further, it has a return lever 30 for releasing the locking action of the lock mechanism 2 by rotating the output gear 11 in the reverse direction.

The steps will be described in detail below. As shown in FIG. 1, the input gear 12 is attached to the input shaft 13.
Is attached. The input gear 12 can be disengaged from the transfer output gear 14 by moving to the left and right in the axial direction as indicated by the arrow in FIG. Input gear 12
Meshes with the output gear 11 when it is in a position to engage the transfer output gear 14 (right in FIG. 1). The output gear 11 has a ball hole 111.
Is provided, and two engaging balls 41 are accommodated therein.

The ball hole 111, as shown in FIG.
A plurality of output gears 11 and output shafts 52 are arranged on the circumference around the axis, and engaging balls 41 are housed in each of them. As shown in FIG. 1, the sum (2D) of the diameters D of the two engaging balls 41 is slightly larger than the thickness T of the output gear 11 (2D> T).

On the other hand, the hub boss 51 is composed of a left long diameter portion 514 and a right short diameter portion 515 as shown in FIG. An engaging groove 511 facing the ball hole 111 is provided on the right side surface 513 of the long diameter portion 514. Also, a relay ring 42, which is coupled to the minor diameter portion 515 of the hub boss 51 by a key 512, rotates integrally with the hub boss 51 and can reciprocate separately in the axial direction.
Is provided. A stopper 44 is attached to the right end of the short diameter portion 515 of the hub boss 51, and an elastic material 43 is interposed between the stopper 44 and the relay ring 42. A coil spring is used as the elastic material 43 in this example.

The relay ring 42, as shown in FIG.
It is a hollow cylindrical body that is fitted into the minor diameter portion 515 of the hub boss 51. As shown in FIGS. 4 and 5, the relay ring 42 is composed of a long diameter flange portion 421 and a tubular portion 422. As shown in FIG. 5, the cylindrical portion 422 is provided with a plurality of accommodation holes 423 intermittently. The accommodation hole 42
As shown in FIG. 1, the elastic member 43 is housed in the housing 3. Further, the key 512 is driven between the relay ring 42 and the hub boss 51 as described above.

On the other hand, the right side surface 11 of the output gear 11
As shown in FIGS. 1 and 4, a lock claw 20 is attached to the step 3 by a stepped bolt 114. Lock claw 2
As shown in FIGS. 3 and 4, 0 is the stepped bolt 114.
It comprises a main arm 201 having a hole 203 through which a sub-arm 202 is inserted, and a sub-arm 202 extending from a tip portion 204 (FIG. 3) of the main arm 201 in a direction perpendicular to the main axis, that is, parallel to the axial direction.

The main arm 201 of the lock pawl 20 is attached so as to be rotatable about the stepped bolt 114 as an axis. A ring groove 205 is provided in the sub arm 202 as shown in FIGS. 3 and 4, and the snap ring 21 is fitted therein. As shown in FIG. 4, in the snap ring 21, the sub-arm 202 is arranged in the axial direction of the hub boss 51, that is, the upper surface 42 of the tubular portion 422 of the relay ring 42.
It is biased in the direction of pressing toward 21.

Further, the flange portion 42 of the relay ring 42
As shown in FIG. 1, the return lever 30 is attached to the No. 1 by the attaching bolt 424. Return lever 3
Reference numeral 0 is a wedge-shaped member as shown in FIG. As shown in FIG. 5, the return lever 30 has the mounting bolts 42
It can be rotated around 4. Also, the mounting bolt 4
A torsion spring 426 is wound around 24 via a coloring ring 425.

One end 42 of the torsion spring 426
61 is fixed to the flange portion 421 of the relay ring 42, and the other end 4262 is the upper slope 30 of the return lever 30.
It is hooked to 3. The torsion spring 426 presses the tip portion 301 of the return lever 30 against the upper surface 4221 of the tubular portion 422 of the relay ring 42, as shown in FIGS. In FIG. 1, reference numeral 52 is an output shaft splined to the hub boss 51,
Reference numeral 53 is a universal joint, reference numeral 54 is a drive shaft for driving a load, and reference numeral 81 is a PTO case.

Next, the function and effect of this example will be described. When the load torque is within the predetermined value T ₀ , the power of the output gear 11 is transmitted to the hub boss 51 by the engagement force between the engagement ball 41 and the engagement groove 511, as in the conventional example. In this case, as shown in FIGS. 4 and 5, the left end surface 4222 of the tubular portion 422 of the relay ring 42 is close to the right end surface 113 of the output gear 11 and is in contact with the engagement ball 41. In addition, the upper left end surface 421 of the flange portion 421
1 is a right end surface 2021 of the sub-arm 202 of the lock claw 20
Is close to.

When overloaded, the engaging ball 41 overcomes the repulsive force of the elastic member 43 and pushes the relay ring 42 back. As shown by the arrow in FIG. 4, the relay ring 42 moves to the right and the lower left end surface 4212 of the flange portion 421 is
The lock claw 20 arrives on the right side of the right end surface 2021 of the sub arm 202. Then, since the snap ring 21 presses the sub-arm 202 in the axial direction, the sub-arm 202 causes the upper surface 42 of the tubular portion 422 of the relay ring 42 to move.
21 (FIGS. 6 and 7).

Then, the upper surface 4221 of the cylindrical portion 422 and the lower surface 2022 of the sub arm 202 contact each other, and the right end surface 2021 of the sub arm 202 contacts the lower left end surface 4212 of the flange portion 421. Therefore, the relay ring 42
Can no longer move to the left from that position.
That is, as shown in FIG. 6, the relay ring 42 is locked by the locking claw 20 by moving to the right by the distance E between the upper left end surface 4211 and the lower left end surface 4212 of the flange portion 421. Therefore, the relay ring 42 is
Do not press.

Therefore, as in the conventional example, the engaging ball 41
Does not repeatedly collide with the engaging groove 511 of the hub boss 51, and the output gear 11 runs idle. Therefore, the engagement ball 41 and the engagement groove 511 are not worn. Further, the elastic material 43 is not subjected to repeated stress. Therefore, the repulsive force of the elastic member 43 does not decrease early, and the set value T ₀ of the overload does not decrease early unlike the conventional example.

During normal operation, as shown in FIG. 5, the output gear 11, the hub boss 51, and the relay ring 4 are
2, the lock claw 20, the snap ring 21, and the return lever 30 are integrally rotated in the same direction. When overloaded, as shown in FIG. 7, the output gear 11, the lock claw 20, and the snap ring 21 continue to rotate,
Hub boss 51, relay ring 42, and return lever 30
Stops rotating. At this time, the upper surface 2023 of the sub-arm 202 of the lock claw 20 has the lower slope 30 of the return lever 30.
2 and rotates against the repulsive force of the torsion spring 426 while flipping up the tip portion 301 of the return lever 30 (change from FIG. 5 to FIG. 7).

When the output gear 11 is rotated in the reverse direction, the lock action of the lock claw 20 is released. That is, as shown in FIGS. 3 and 9, when the lock claw 20 moves in the opposite direction, the sub arm 202 of the lock claw 20 rides on the upper slope 303 of the return lever 30. Then, the sub arm 202 overcomes the pressing force of the snap ring 21 and rises. The lower surface 2022 of the sub arm 202
Rise above the step surface 4213 of the flange portion 421 of the relay ring 42 shown in FIG. Then, the relay ring 42 is pressed to the left by the elastic member 43,
The lock of the lock claw 20 is released, and the steady state as shown in FIG. 4 is restored.

Then, the relay ring 42 again presses the engaging ball 41. Then, when the output gear 11 rotates and the engagement ball 41 reaches the position of the engagement groove 511 of the hub boss 51, both are engaged again and the hub boss 51 rotates. As described above, according to the present example, the PTO power with overload safety device that does not easily deteriorate due to wear or the like in the coupling portion of the torque transmission and that does not change the operating value of the overload safety operation over time. A transmission device can be provided.

[Brief description of drawings]

FIG. 1 is an overall explanatory diagram of a power transmission device according to an embodiment.

FIG. 2 is a sectional view taken along the line BB of FIG.

FIG. 3 is a perspective view around a lock claw and a return lever in the embodiment.

FIG. 4 is a side view of the vicinity of the lock mechanism under a steady load in the embodiment.

5 is a cross-sectional view taken along the line C-C of FIGS. 1 and 4 under a steady load.

FIG. 6 is a side view around the lock mechanism at the time of overload in the embodiment.

FIG. 7 is a cross-sectional view taken along the line CC of FIGS. 1 and 6 at the time of overload.

FIG. 8 is a side view around the lock mechanism at the start of the lock release operation in the embodiment.

FIG. 9 is a C of FIGS. 1 and 8 at the time of starting the unlocking operation.
-C arrow line sectional view.

FIG. 10 is an overall explanatory view of a conventional power transmission device.

11 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1. ． ． Power transmission device, 11. ． ． Output gear, 12. ． ． Input gear, 13. ． ． Transfer output gear, 20. ． ． Lock claw, 2. ． ． Locking mechanism, 21. ． ． Snap ring, 30. ． ． Return lever, 41. ． ． Engagement ball, 42. ． ． Relay ring, 43. ． ． Elastic material, 51. ． ． Hub boss, 511. ． ． Engagement groove, 52. ． ． Output shaft, 53. ． ． Universal joint, 54. ． ． Drive shaft, 81. ． ． PTO case,

Claims (1)

[Claims] 1. A PTO power transmission device having an output gear meshing with an input gear, an output shaft, and a hub boss interposed therebetween, wherein the power transmission device is a ball hole of the output gear. Inserted into the hub, a relay ring that presses the engagement ball into the engagement groove of the hub boss, a stopper fixed to the hub boss, and the relay ring provided between the stopper and the relay ring. A lock mechanism for locking the pressing action of the relay ring to stop the pressing force on the engaging ball when an overload occurs, and an elastic member for applying a pressing force to the output gear. A PTO power transmission device with an overload safety device, comprising: a return lever that releases a locking action of a lock mechanism.