JP3391942B2 - Planetary transmission - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planetary transmission device, and more particularly to a planetary transmission device that performs gear shifting by preventing rotation of a ring gear.

[0002]

2. Description of the Related Art There are various types of transmissions,
Generally, it is possible to obtain outputs with different reduction ratios by changing the combination of gears from the input shaft to the output shaft.Especially for electric tools such as electric drill drivers. A planetary gearbox using a planetary gear mechanism is widely used in which the input shaft and the output shaft can be arranged concentrically and can be made compact in comparison with the reduction ratio obtained.

In this planetary transmission, the ring gear in the planetary mechanism is allowed to rotate freely so that different reduction ratios can be obtained when the ring gear freely rotates and when the ring gear is prevented from rotating. There is something I did. For example, as disclosed in Japanese Unexamined Patent Publication No. 63-151545, two sun gears having different numbers of teeth are fixed to an input shaft, and two kinds of planet gears respectively meshing with these sun gears are combined into a single planetary gear. Supported by a carrier,
Further, two ring gears that mesh with the planetary gears of both types are provided to prevent rotation of one ring gear and rotation of the other ring gear of the two ring gears that are both freely rotatable. There is a device in which it is possible to obtain outputs with different reduction ratios depending on the blocked state.

In such a type of planetary transmission, a switching member that engages with the ring gear to prevent rotation of the ring gear is required for speed change. The switching member is formed as a single member that engages with one of the plurality of engaging protrusions provided on the outer surface of the ring gear .

[0005]

In this case, when the switching member is engaged with the ring gear and the rotation of the ring gear is prevented, the ring has a problem due to the strength of the switching member and uneven load application. This causes gear eccentricity, which causes a situation in which the transmission efficiency of the planetary gear mechanism deteriorates.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a planetary transmission which does not cause deterioration of transmission efficiency due to eccentricity of the ring gear when the ring gear is rotationally fixed. There is.

[0007]

SUMMARY OF THE INVENTION The present invention, however, is provided with a switching member for preventing rotation of the ring gear by engaging with a freely rotatable ring gear in a planetary mechanism, and the ring gear by the switching member is provided. In a planetary transmission that shifts gears by switching between a rotation blocking state and a free rotation state of a ring gear, a switching member is formed in a ring shape arranged concentrically with the ring gear and arranged along the outer periphery of the ring gear . with axial movement against the ring gear on the inner circumferential surface thereof
At the same time with multiple engaging protrusions provided on the outer circumference of the ring gear
Providing a plurality of protrusions that engage with each other at equal intervals in the circumferential direction
In particular has a feature there. By preventing rotation of the ring gear at a plurality of locations in the circumferential direction rather than at a single location, eccentricity of the ring gear is not induced.

The switching member is driven by a flat plate-shaped switching lever that is swingably supported by an axis in a direction orthogonal to the axial direction of the planetary mechanism, and is brought into an engagement position and a non-engagement position with a ring gear. It is preferable to use one that moves between the switching members, and it is preferable to drive the switching member with a fork-shaped connecting portion that sandwiches the connecting shaft projecting from the switching member from the front and the rear in the moving direction of the switching member.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the illustrated embodiment. The electric tool shown in FIG. 2 is an electric drill driver, and the power from the motor 6 to the chuck 50 in this electric tool is increased. First, the transmission mechanism and the speed change mechanism will be described. As shown in FIGS. 1 and 3, the output shaft 60 of the motor 6 arranged on one end opening side of the gear case 1 will be described.
Two sun gears 11 and 12 having different numbers of teeth are fixed to the sun gears 11, 12, and a plurality of planet gears 21 and 22 are provided in each of the sun gears 11 and 12 arranged in the axial direction.
Are in mesh. Both planetary gears 2 with different numbers of teeth
Both 1 and 22 are supported by the carrier 4,
The planetary gears 21 are supported at equal intervals around the sun gear 11, and the planetary gears 22 are supported at equal intervals around the sun gear 12. Both planetary gears 21 and 22 rotate individually, but perform the same revolution. Has become.

The planet gear 21 is engaged with the ring gear 31 arranged concentrically with the output shaft 60, and the ring gear 32 also arranged concentrically with the output shaft 60 is engaged with the planet gear 22. Of these two ring gears 31, 32 arranged in the axial direction, the ring gear 31 has a plurality of engaging projections 35 on its outer peripheral surface as shown in FIGS. 1 and 6.
Are formed at equal intervals in the circumferential direction, and are freely rotatable with respect to the gear case 1. Ring gear 3
The ring gear 32 is also freely rotatable with respect to the gear case 1, and the ring gear 32 has an inner race 3 of a one-way clutch 33 having the gear case 1 as an outer race 330.
It also serves as 31.

The one-way clutch 33 here is
As described above, the gear case 1 is used as the outer race 330 and the ring gear 32 is used as the inner race 331.
A freewheel type formed by arranging rollers 332 in a wedge-shaped space formed between 0 and 331,
As shown in FIGS. 6 to 8, two kinds of wedge-shaped spaces having different narrowing directions are provided, and a drive piece 77 protruding from the forward / reverse switching ring 76 is located between the two kinds of wedge-shaped spaces. By rotating the forward / reverse switching ring 76 with respect to the gear case 1, the pair of rollers 33 located on both sides of the driving piece 77 are rotated.
It is possible to switch the rotatable direction of the ring gear 32, which is the inner race 331, depending on which of the two, 332 is pressed by the drive piece 77.

That is, when the forward / reverse switching ring 76 rotates in one direction and the driving piece 77 pushes the left side roller 332 in FIG. 7 into the wider side of the wedge-shaped space, the right side roller 33.
2 is positioned in a narrow portion of the wedge-shaped space by the bias of the spring 333, and in this state, the ring gear 32 in the clockwise direction in the drawing
The (inner race 331) can rotate, but the ring gear 32 is prevented from rotating counterclockwise. When the driving piece 77 pushes the roller 332 on the right side in the figure to the right side in the figure, conversely, the ring gear 32 (inner race 331) is allowed to rotate counterclockwise and is blocked from rotating clockwise.

In the gear case 1, in addition to the planetary mechanism, the forward / reverse switching ring 76 and the one-way clutch 33, a switching ring 70 is arranged. As shown in FIGS. 1 and 8, the switching ring 70 that is slidable in the axial direction is provided with a plurality of projections 71 at equal intervals in the circumferential direction. When a plurality of protrusions 71 are engaged with the plurality of engagement protrusions 35 on the outer peripheral surface of the ring 31, the rotation of the ring gear 31 is blocked, and the engagement between the engagement protrusions 35 and the protrusions 71 is released by the sliding. , Allow rotation of the ring gear 31. When the rotation of the ring gear 31 is blocked, the engagement projection 35 and the projection 71 are engaged at a plurality of positions in the circumferential direction at the same time, so that the ring gear 31 is eccentric even if the switching ring 70 is not very strong. There is no.

The axial slide of the switching ring 70 is
This is done by an electromagnetic drive member 7 such as a solenoid and a switching lever 65. The switching lever 65 has a U-shape, and both side pieces have a shaft 6 in a direction orthogonal to the axial direction of the planetary mechanism.
6, 66 is a flat plate-like member that is swingably supported by the gear case 1, and a fork-shaped portion at one end of each side of the switching lever 65 whose central portion is connected to the electromagnetic drive member 7 is an outer peripheral surface of the switching ring 70. From the pair of connecting shafts 72, 72
Are engaged with each other. The two connecting shafts 72, 72 are formed so that the line connecting the two passes through the center of the switching ring 70. Therefore, when the switching lever 65 swings around the shaft 66 to move the switching ring 70 in the axial direction, the switching ring 7
0 makes smooth axial movement. The reason why the switching lever 65 is formed of a flat plate-shaped member is to increase the degree of freedom in its shape, and the fork-shaped portions at the ends of both ends of the switching lever 65 sandwich the connecting shaft 72 respectively. This is to improve the workability and the assemblability.

The carrier 4 supporting the planetary gears 21 and 22 is integrally provided with a sun gear 41, and the rotation of the sun gear 41 supports the planetary gear 42 meshing with the sun gear 41 and the ring gear 43. The rotation of the carrier 44 is transmitted to the output shaft 5 through the auto-lock mechanism 55. The autolock mechanism 55 here has a function of automatically locking the output shaft 5 with respect to the gear case 16 when the rotation of the motor is stopped, and automatically releasing this lock when the motor is rotated. However, description of this point will be omitted. Further, the ring gear 43 is also freely rotatable,
By engaging the ball 48 with the ring gear 43 by the spring pressure of the clutch spring 47 shown in FIG. 2, a torque limiter that disconnects the output shaft 5 and the sun gear 41 when the load torque exceeds a predetermined value is configured. However, the description of this point is also omitted.

Now, as shown in FIG. 1 (a), the switching ring 7
The respective projections 71 of 0 engage the respective engagement projections 35 to prevent the ring gear 31 from rotating, and the one-way clutch 33 is set so that the ring gear 32 is rotatable in the direction indicated by the arrow in the figure. At this time, when the motor 6 is rotated, the rotation output is transmitted to the carrier 4 through the planetary gear 21 that meshes with the ring gear 31 that is prevented from rotating. At this time, the ring gear 32 idles in the direction opposite to the output shaft 5, but this idle is in the direction in which the rotation shown by the arrow in the figure is permitted.

When the electromagnetic drive member 7 is operated to move the switching ring 70 as shown in FIG. 1 (b) to release the engagement between the engagement protrusions 35 and the protrusions 71, the ring gear is released. 31 becomes free, and the stop of the carrier 4 connected to the load tries to rotate the ring gears 31 and 32 by the rotation of the planetary gears 21 and 22 meshing with the sun gears 11 and 12. Since the rotation direction is opposite to that in the idling state, that is, the rotation is blocked by the one-way clutch 33, the carrier 4 and the output shaft 5 are transmitted through the planetary gear 22 meshed with the ring gear 32 from this point. Power is transmitted to.

Since the number of teeth of the sun gear 12 is smaller than the number of teeth of the sun gear 11 and the number of teeth of the planetary gear 22 is larger than the number of teeth of the planetary gear 21, the high speed rotation low torque state is changed to the low speed rotation high torque state. It has been switched. The rotation of the ring gear 32 may be prevented by using the switching ring 70 as in the case of the ring gear 31, but when the one-way clutch 33 is used as in the illustrated example, the rotation of the ring gear 32 is prevented. When stopping, the switching ring 70 is simply separated from the locking projection 35 of the ring gear 31, and a member that causes a collision to prevent the rotation of the ring gear 32 is unnecessary. In order to perform a smooth and noise-free speed change, a low-speed rotation high-torque state can be returned to a high-speed rotation low-torque state while the motor 6 is stopped due to the nature of the electric drill driver. Therefore, the collision between the locking projection 35 and the projection 71 when the rotation of the ring gear 31 is prevented does not pose a problem.

By rotating the forward / reverse switching ring 76,
When the rotation restriction direction of the one-way clutch 33 is reversed and the rotation direction of the motor 6 is reversed, initially,
Power is transmitted to the carrier 4 through the planetary gear 21 that meshes with the ring gear 31 whose rotation is stopped by the switching ring 70. At this time, the ring gear 32 idles in the rotatable direction of the one-way clutch 33, and the increase in load is detected. When the electromagnetic drive member 7 operates and the ring gear 31 becomes free, the power is transmitted to the carrier 4 through the ring gear 32 whose rotation is blocked by the one-way clutch 33 and the planetary gear 22 meshing with the ring gear 32. Although there is only one one-way clutch 33, the rotation blocking direction can be switched so that the same operation can be obtained in the forward rotation and the reverse rotation required for the electric drill driver.

The forward / reverse switching ring 76 in the illustrated example.
Is the rotation direction switching rod 8 and the gear case 1 shown in FIG.
Is pivotally supported by a shaft 91, one end of which is connected to the rotation direction switching rod 8,
A switching lever 90 having the other end engaged with the forward / reverse switching ring 76.
Made by and. The rotation direction switching rod 8 here is also interlocked with the switch unit SW shown in FIG. 2, and the rotation direction of the motor 6 is switched at the same time.
The switch unit SW also controls energization of the motor 6 when the trigger switch 9 is pulled and also controls the rotation speed of the motor 6 according to the pulling amount of the trigger switch 9. However, description of this point is omitted. To do.

4 to 9 show the order of assembling the respective parts into the gear case 1. After the switching lever 90 and the lid member 10 are mounted, as shown in FIG. 5, the forward / reverse switching ring 76 is provided. And the carrier 4, and then, as shown in FIG. 6, the planetary gear 22 and the ring gear 32 and the one-way clutch component, the planetary gear 21 and the ring gear 31 as shown in FIG. 7, and the switching as shown in FIG. After the rings 70 are housed in order, the thrust plate 19 is mounted and assembled as shown in FIG. The protrusion 13 in the figure is the forward / reverse switching ring 7
In order to reduce the mechanical loss by eliminating the sliding resistance between the forward / reverse switching ring 76 and the ring gear 32 while ensuring the operation space of 6, the ring gear 32 functions as a thrust receiving surface. It is formed integrally with a lid member 10 that fits into one end of the gear case 1. The three projections 13 provided in the illustrated example also have the functions of positioning and centering the lid member 10 with respect to the gear case 1.

In the above-described embodiment, the switching ring 70 is driven by the electromagnetic drive member 7 which is advantageous for obtaining the automatic shifting due to the increase of the load, but the shifting ring 70 is manually operated. It may be moved to change gears. However, even in the case of manual operation, in view of smooth movement of the switching ring 70, the switching ring 70 is not directly operated but the switching switching lever 6 is operated.
It is preferable that gear shift is performed by operating 5.

[0023]

As described above, in the present invention, the switching member is formed in a ring shape which is arranged concentrically with the ring gear.
Together are arranged along the outer periphery of the ring gear, its
Ringugi on the inner peripheral surface in the axial direction movement against the ring gear
(A) Engages simultaneously with a plurality of engaging protrusions provided on the outer periphery of
Since the plurality of protrusions are provided at equal intervals in the circumferential direction and the rotation of the ring gear is not blocked by the switching member at one place, the strength of the switching member is not so high because it is performed at a plurality of positions in the circumferential direction. In both cases, the eccentricity of the ring gear is not induced, and therefore the situation that the transmission efficiency of the planetary gear mechanism is deteriorated due to the eccentricity of the ring gear is not caused.

The switching member is driven by a flat plate-shaped switching lever which is swingably supported by a shaft in a direction orthogonal to the axial direction of the planetary mechanism so that the switching member is engaged with and disengaged from the ring gear. When using one that moves between the switching members, the degree of freedom of the shape of the switching lever can be increased, and the switching member can be connected by a fork-shaped connecting portion that sandwiches the connecting shaft protruding from the switching member from the front and the rear in the moving direction of the switching member. When the switching lever is driven, it can be easily engaged with the connecting shaft when the switching lever is assembled, so that the assembling property is improved.

[Brief description of drawings]

1A and 1B show an embodiment of the present invention, in which FIG. 1A is a perspective view showing before shifting, and FIG. 1B is a perspective view showing after shifting.

FIG. 2 is a partially cutaway side view of the above.

FIG. 3 is a vertical cross-sectional view of the transmission mechanism portion of the above.

FIG. 4 is a rear view of the same gear case and lid member.

FIG. 5 is a rear view of the same gear case in which a forward / reverse switching ring and a carrier are incorporated.

FIG. 6 is a rear view showing a state in which a one-way clutch constituent member, a ring gear and a planetary gear are further incorporated in the above gear case.

FIG. 7 is a rear view showing a state in which another ring gear and a planetary gear are incorporated in the same gear case.

FIG. 8 is a rear view showing a state in which a switching ring is further incorporated in the above gear case.

FIG. 9 is a rear view showing a state in which a thrust plate is further attached to the same gear case.

[Explanation of symbols]

31 ring gear 35 Locking protrusion 65 Switch lever 70 Switching ring 71 protrusion

Claims (3)

(57) [Claims] 1. A planetary mechanism comprising a switching member for preventing rotation of the ring gear by engaging with a freely rotatable ring gear, wherein the ring gear is prevented from rotating by the switching member and the ring gear freely rotates. In a planetary transmission that shifts gears by switching between the ring gear and the ring gear, the switching member is formed in a ring shape that is arranged concentrically with the ring gear, and
Together they are arranged, provided on the outer periphery of the ring gear in the axial movement of <br/> against the ring gear on an inner peripheral surface thereof a plurality
A plurality of protrusions that engage simultaneously with the
A planetary transmission characterized in that it is provided at regular intervals . 2. The switching member is driven by a flat plate-shaped switching lever that is swingably supported by a shaft in a direction orthogonal to the axial direction of the planetary mechanism, and is brought into an engagement position and a non-engagement position with a ring gear. The planetary transmission device according to claim 1, wherein the planetary transmission device moves between the two. 3. The switching lever is configured to drive the switching member with a fork-shaped connecting portion that sandwiches a connecting shaft projecting from the switching member from the front and the rear in the moving direction of the switching member. Planetary gearbox.