JP3391932B2 - 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 using a planetary mechanism.

[0002]

2. Description of the Related Art As a transmission, there is a transmission in which a plurality of planetary mechanisms are arranged in the axial direction and the rotational restraint of a plurality of members in these planetary mechanisms is selectively performed to obtain outputs of different gear ratios. . Such a planetary transmission is widely used in electric tools because the input shaft and the output shaft can be arranged concentrically and can be made compact as compared with the obtained reduction ratio. By using such a transmission, the power tool can perform initial work with low torque and high speed rotation and final work with high torque and low speed rotation during screw tightening and drilling work, resulting in high work efficiency. It will be demonstrated.

For example, in Japanese Patent Laid-Open No. 63-101545, there are provided two sun gears which are coaxially provided and rotate integrally with each other.
A planetary gear of one kind, two kinds of ring gears that mesh with each planetary gear, and a carrier that supports each planetary gear together are provided, and the rotation of the two kinds of ring gears that are freely rotatable is selectively selected. It is disclosed that the output of different gear ratios can be taken out from the carrier depending on which of the ring gears is stopped to stop the rotation, and Japanese Patent Laid-Open Publication No. 63-186054 discloses that By providing a member that switches the ring gear that moves according to the load applied to the ring gear and blocks rotation, it is possible to automatically shift gears according to the magnitude of the load without manual operation. It is shown.

[0004]

[0005]

[0006]

However, according to the above mechanism,
When changing gears, the ring gear that stops rotation and this ring
Output is taken out by the planetary gear that meshes with the gear
The ring gear that does not stop the rotation is output
It is in a state of idling while taking out. others
In order to change gears during operation, the rotation of the ring gear during idling should be
At this time, the ring gear rotation is blocked.
Due to the setting of the stopping force,
Rotation of the ring gear by engaging the rotation prevention member
Between the ring gear and the rotation prevention member
Collisions, and this collision causes noise and vibration.
The ring gear and the rotation prevention member have a long service life.
Will lower it. Ring gear with one-way clutch
Support the ring gear by the one-way clutch
Preventing the above collision by preventing rotation.
It is also possible, but if a one-way clutch consisting of an outer race or an inner race is further interposed between the gear case housing the planetary speed change mechanism and the outer circumference of the ring gear arranged in the gear case, the gear case As a result, a large diameter is required, and the size becomes large as a whole, and it becomes a problem in terms of weight and bulk to be applied to a portable power tool or the like.

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 device which utilizes a one-way clutch to avoid the occurrence of a collision and to reduce the size and weight. It is in.

[0008]

DISCLOSURE OF THE INVENTION In the present invention, however, a plurality of planetary mechanisms, each of which is composed of a sun gear, a planet gear that meshes with the sun gear, and a ring gear that is concentric with the sun gear and that meshes with the planet gear, are provided in the axial direction, and each planet is At least one of the ring gears in the mechanism is provided with at least one planetary transmission that blocks the rotation of one of the ring gears and extracts the output by rotatably rotating the other while switching the reduction ratio by selecting the ring gear that blocks the rotation. supporting Then together through a one-way clutch that freely rotates a ring gear only in one direction
In addition, it is not supported by the one-way clutch
The latter is equipped with a lock member that prevents rotation of the ring gear.
When the ring gear of the
The former ring gear supported by the
The rotation is blocked by the
One-way clutch in the rotation blocking state of the person's ring gear
The former ring gear supported by the switch
And is formed between the outer race and the inner race and between both races.
Formed as balls arranged in a wedge-shaped space
Serial one-way clutch is a gear case that the outer race has met with the planetary mechanism, the inner race and has a particular characteristic is formed by the ring gear.

The gear case here may be provided with a protrusion serving as a thrust receiving surface of the component,
In this case, the protrusion may be formed integrally with a lid member that is arranged on one end surface of the tubular gear case and that fits with the gear case. The gear case is made of sintered metal,
What is formed as a laminated body of metal annular thin plates, is preferably made of synthetic resin, and only the one-way clutch portion is made of metal.

Further, the one-way clutch may be such that its rotatable direction can be switched.

[0011]

According to the present invention, the ring gear supported by the one-way clutch is prevented from rotating by the one-way clutch without engaging the rotation-preventing member, so that a collision does not occur and the one-way clutch is used. Since the gear case also serves as the outer race and the ring gear serves as the inner race, the diameter can be reduced.

If the gear case is provided with a protrusion that serves as the thrust receiving surface of the constituent member of the planetary mechanism, the mechanical loss due to the sliding resistance against the rotation of the constituent member of the planetary mechanism can be reduced. In this case, if the protrusion is formed integrally with the lid member that is arranged on one end surface of the tubular gear case and fits into the gear case, the gear case can be easily manufactured.

If the gear case is formed of a sintered metal or a laminated body of metal annular thin plates, it is easy to manufacture a gear case having a complicated shape to serve also as an outer race. If it is made of synthetic resin and only the one-way clutch part is made of metal, it is possible to reduce the weight while ensuring the required strength.

Further, if the one-way clutch is such that the rotatable direction thereof is switchable, it can be applied to an electric driver, which is functionally required to rotate in the forward and reverse directions.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment for an electric tool such as an electric drill driver shown in the drawings. An output shaft 6 of a motor 6 arranged on one end opening side of a gear case 1
Two sun gears 11 and 12 having different numbers of teeth are fixed to 0, and a plurality of sun gears 11 and 12 arranged in the axial direction, three planet gears 21 and 2, respectively, in the illustrated example.
Two 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 lined up in the axial direction, the ring gear 31 has a plurality of engaging projections 35 on its outer peripheral surface as shown in FIGS. 5 and 8.
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 balls 332 in a wedge-shaped space formed between 0 and 331,
In addition to having two types of wedge-shaped spaces with different narrowing directions,
A drive piece 77 projecting from the forward / reverse switching ring 76 is located between the two kinds of wedge-shaped spaces, and the forward / reverse switching ring 76 is rotated with respect to the gear case 1 so as to be positioned on both sides of the drive piece 77. Depending on which one of the pair of balls 332, 332 is pressed by the drive piece 77, the rotatable direction of the ring gear 32 which is the inner race 331 can be switched.

That is, when the driving piece 77 pushes the ball 332 on one side into the wider side of the wedge-shaped space as shown in FIG. 9, the other ball 332 is positioned in the narrow portion of the wedge-shaped space by the bias of the spring 333. In this state, rotation of the ring gear 32 (inner race 331) in the direction of arrow A in the figure is possible, but rotation of the ring gear 32 in the direction of arrow B in the figure is blocked. When the driving piece 77 pushes the ball 332 on the right side in the figure to the right side in the figure, on the contrary, the ring gear 32 (inner race 331) in the direction of the arrow B in the figure can be rotated and the ring gear 32 in the direction of the arrow A. Rotation is blocked.

In the gear case 1, in addition to the planetary mechanism, the forward / reverse switching ring 76, the one-way clutch 33, a locking ring 70 is arranged. As shown in FIGS. 6 and 8, the locking ring 70 that is slidable in the axial direction includes a protrusion 71 that engages with the engaging protrusion 35 on the outer peripheral surface of the ring gear 31 when moved in one direction. This engagement prevents the ring gear 31 from rotating, and also allows the ring gear 31 to rotate when the sliding disengages the engagement protrusion 35 and the protrusion 71. The axial slide of the locking ring 70 is a switching drive member 7 such as a solenoid shown in FIGS. 8 and 11, and an outer surface of the gear case 1 is pivotally supported by a shaft 66 and one end thereof is connected to the switching drive member 7. The other end is formed by a lever 65 connected to a connecting shaft 72 protruding from the outer peripheral surface of the locking ring 70.

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, 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, a description of this point will also be omitted.

Now, as shown in FIG. 8 (a), the locking ring 7
When 0 is blocking the rotation of the ring gear 31 and the one-way clutch 33 is set so that the ring gear 32 can rotate in the direction shown by the arrow in the figure, if the motor 6 is rotated, the rotation output will be , Is transmitted to the carrier 4 through the planetary gear 21 that meshes with the ring gear 31 whose rotation is blocked. At this time, the ring gear 32 has the output shaft 5
Idling in the opposite direction, but this idling is the direction in which the rotation shown by the arrow in the figure is permitted.

Then, the switching drive member 7 operates in response to an increase in the load detected by the rotation speed detecting means of the motor 6, etc., and the locking ring 70 moves and engages as shown in FIG. 8 (b). When the engagement between the protrusion 35 and the protrusion 71 is released, the ring gear 31 becomes free, and the stop of the carrier 4 connected to the load is stopped by the rotation of the planet gears 21 and 22 meshing with the sun gears 11 and 12. 32 tries to rotate, but the rotation direction of the ring gear 32 at this time is
One-way clutch 3 in the opposite direction to that when idling
Since the rotation is blocked by 3, the power is transmitted to the carrier 4 and the output shaft 5 from this point through the planetary gear 22 meshed with the ring gear 32.

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. Moreover, in this gear shifting, the one-way clutch 33 is used to stop the rotation of the ring gear 32, so that only the locking ring 70 is separated from the locking projection 35 of the ring gear 31, and the collision is performed to prevent the rotation of the ring gear 32. Therefore, smooth and noise-free gear shifting is performed despite the fact that there is no member that causes the occurrence of gear shifting and therefore the gear shifting is in operation. The return from the low-speed rotation high-torque state to the high-speed rotation low-torque state is performed by the return of the switching drive member 7, and this shift is performed when the motor 6 is stopped or the motor 6 is started.

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 locking ring 70. At this time, the ring gear 32 idles in the rotatable direction of the one-way clutch 33, which increases the load. When the switching drive member 7 is actuated and the ring gear 31 becomes free upon detection, 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. If the motor 6 is rotated only in one direction, the one-way clutch 33 does not need to be able to switch the rotation blocking direction.

The forward / reverse switching ring 76 in the illustrated example.
Is a rotation direction switching rod 8 shown in FIG. 10, and one end of the rotation direction switching rod 8 is supported by the gear case 1 by a shaft 91.
And a switching lever 90 having the other end engaged with the forward / reverse switching ring 76. The rotation direction switching rod 8 here is also interlocked with the switch unit SW shown in FIG. 11, 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 handle 9 is pulled and also controls the rotation speed of the motor 6 according to the pull amount of the trigger switch handle 9. This point will be described. Is omitted. Further, although the slide driving of the locking ring 70 for gear shifting is performed by the switching driving member 7, the present invention is not limited to this, and may be manually performed.

By the way, when the outer race 330 of the one-way clutch 33 is also used as the gear case 1, the gear case 1 is not a mere container but requires high strength.
It has to be composed of metal. On the other hand, the surface for forming the wedge-shaped space must be formed on the inner surface of the gear case 1,
Since the shape of the inner surface is complicated, the cutting process becomes difficult.
For this reason, here, the gear case 1 is formed as a molded product of sintered metal to cope with this point and avoid an increase in cost. Also, the gear case 1 is usually
Although the number of components is as small as possible, in order to reduce the mechanism loss by eliminating the sliding resistance between the forward / reverse switching ring 76 and the ring gear 32 while ensuring the operating space of the forward / reverse switching ring 76, If the protrusion 13 serving as the thrust receiving surface of the gear 32 is also provided on the gear case 1, the moldability of the gear case 1 is extremely deteriorated. Therefore, one end of the gear case 1 is a lid member 10 which is a separate member here. The projection 13 is also formed integrally with the lid member 10 fitted to one end of the gear case 1. In the illustrated example, 3
The individually provided protrusions 13 also have a function of positioning and centering the lid member 10 with respect to the gear case 1.

Incidentally, FIGS. 2 to 7 show the order of assembling the respective parts into the gear case 1, and the switching lever 9
0 and the lid member 10 are mounted, the forward / reverse switching ring 76 and the carrier 4 are housed as shown in FIG. 3, and then the planetary gear 22, the ring gear 32, and the one-way clutch constituent member, as shown in FIG. 5, the planetary gear 21
6, the ring gear 31, and the locking ring 70 as shown in FIG. 6 in that order, and then the thrust plate 19 as shown in FIG.
Attach and assemble.

The gear case 1 having the above-mentioned shape may be formed not as a molded product made of a sintered metal but as a laminated body of metal annular thin plates. By stacking punched metal sheets in the required shape, the required shape is obtained.
Also in this case, the manufacturing is facilitated and the cost can be reduced. Further, if the entire gear case 1 is made of metal, a new problem arises in terms of weight, but a portion requiring strength, that is, the outer race 3 of the one-way clutch 33.
Only the portion to be 30 can be made of metal and the other portions can be made of synthetic resin to reduce the weight. In this case, the metal portion may be insert-molded.

[0029]

As described above, in the present invention, the ring gear supported by the one-way clutch is prevented from rotating by the one-way clutch without engaging the rotation-preventing member, so that no collision occurs. ,
Therefore, in addition to the smooth gear shifting operation, the outer race of the one-way clutch is also used as the gear case, and the inner race is also used as the ring gear. The diameter is hardly increased, and the structure can be made lightweight and small.

Further, when the gear case is provided with the projection which becomes the thrust receiving surface of the constituent member of the planetary mechanism, the mechanical loss due to the sliding resistance against the rotation of the constituent member of the planetary mechanism can be reduced. Especially, if the protrusion is integrally formed on the lid member that is arranged on one end surface of the tubular gear case and fits with the gear case, the gear case that also serves as the outer race can be easily manufactured.

By forming the gear case with a sintered metal or as a laminated body of metal annular thin plates, it is possible to easily manufacture a gear case having a complicated shape to serve also as an outer race. At the same time, the cost can be reduced, and if only the one-way clutch part is made of synthetic resin and made of metal, the required strength can be secured and the weight can be reduced.

Further, if the one-way clutch is such that the rotatable direction thereof is switchable, it can be applied to an electric driver, which is functionally required to rotate in the forward and reverse directions.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment.

FIG. 2 is a rear view of the same gear case and lid member.

FIG. 3 is a rear view showing a state in which a forward / reverse switching ring and a carrier are incorporated in the above gear case.

FIG. 4 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. 5 is a rear view showing a state in which another ring gear and a planetary gear are incorporated in the same gear case.

FIG. 6 is a rear view showing a state in which a locking ring is further incorporated in the above gear case.

FIG. 7 is a rear view showing a state in which a thrust plate is further attached to the above gear case.

8A and 8B show the same operation, and FIG. 8A is a perspective view showing a state before shifting, and FIG. 8B is a perspective view showing a state after shifting.

FIG. 9 is an explanatory diagram of a rotation direction switching portion of the above one-way clutch.

FIG. 10 is a cross-sectional view showing a rotation direction switching operation unit in an electric power tool including the planetary transmission according to the present invention.

FIG. 11 is a partially cutaway side view of the above power tool.

[Explanation of symbols]

1 gear case 22 planetary gears 32 ring gear 33 one-way clutch

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16H 3/44 B25B 21/00 520

Claims (7)

(57) [Claims] 1. A plurality of planetary mechanisms, each of which is composed of a sun gear, a planetary gear meshing with the sun gear, and a ring gear concentric with the sun gear and meshing with the planetary gear, are provided in the axial direction, and one rotation of the ring gears in each planetary mechanism is performed. In the planetary transmission that switches the reduction ratio by selecting the ring gear that blocks rotation and outputs the output by making the other rotatable, and at least one ring gear is rotatable only in one direction. It is supported through the one-way clutch and is supported by the one-way clutch.
Locking member to prevent rotation of non-rotatable ring gear
In the state where the latter ring gear is rotatable,
The former ring gear supported by the one-way clutch is
With the one-way clutch to prevent rotation,
When the latter ring gear is blocked by the
Rotate the former ring gear supported by the one-way clutch.
The outer race and inner race and both
The balls are arranged in a wedge-shaped space formed between the bases.
The one-way clutch which is formed Te has an outer race
Is a gear case accommodating the planetary mechanism, wherein the inner race is formed by the ring gear. 2. The planetary transmission according to claim 1, wherein the gear case includes a protrusion that serves as a thrust receiving surface of a component of the planetary gear mechanism. 3. The planetary transmission device according to claim 2, wherein the protrusion is formed integrally with a lid member that is arranged on one end surface of the cylindrical gear case and that fits with the gear case. 4. The planetary transmission according to claim 1, wherein the gear case is made of sintered metal. 5. The planetary transmission according to claim 1, wherein the gear case is formed as a laminated body of metal annular thin plates. 6. The planetary transmission according to claim 1, wherein the gear case is made of synthetic resin and only the one-way clutch part is made of metal. 7. The planetary transmission according to claim 1, wherein the one-way clutch has a rotatable direction that can be switched.