JPH0914433A - Transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption required for speed change by providing on a speed change mechanism part, a switching member to execute the speed change and an electromagnetic driving member by which the switching member is driven, and forming the electromagnetic driving member in such a manner that return from a high reduction ratio condition to a low reduction ratio condition can be carried out by manual input. SOLUTION: In an electric tool such as an electric drill driver, in the case that a motor is rotated when a switching member 70 blocks the rotation of a ring gear 31, the rotational output of the motor is transmitted to a carrier 4 through a planetary gear 21 engaged with the ring gear 31. An electromagnetic driving member 7 which is a keep solenoid is operated according to the increment of a load detected by engine speed detecting means and so on so as to move the switching member 70 and release the switching member 70 from being engaged with the projection of an engaging projection 35, so that the ring gear 31 is set free. The stopping of the carrier 4 linked with the load is going to rotate ring gears 31, 32 through planetary gears 21, 22 so that power is transmitted to the output axis 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed change device, and more particularly to a speed change device that performs a speed change operation by an electromagnetic force for an electric power tool.

[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 transmission using a planetary 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 obtained reduction ratio.

In such a transmission, the gear change is performed by changing the combination of gears as described above. For this reason, a switching member for changing the combination and the switching member are driven. However, a drive member for the above is required.
As shown in the publication, when a solenoid, which is an electromagnetic actuator, is used as a drive member, electric shift control can be performed.

However, since the solenoid conventionally used in the transmission is to hold the plunger, which is attracted by the exciting attraction force against the bias of the spring, by the exciting attraction force, the solenoid is used by the exciting attraction force. After switching to a predetermined reduction ratio, the solenoid must be continuously energized in order to maintain this reduction ratio, and there is a problem in battery consumption when it is adopted in a device that uses a battery as a power source.

In order to cope with this point, a keep solenoid, for example, an attracting state of a plunger is held by a built-in permanent magnet as an electromagnetic drive member for driving a switching member for causing the speed change mechanism section to change gears, and the plunger is projected. A keep solenoid whose state is held by a spring may be used.
An example is shown in FIG. Input shaft 6 which is the output shaft of motor 6
Two sun gears 11 and 12 formed as one body and having different numbers of teeth are fixed to 0, and planet gears 21 and 22 are respectively meshed with these sun gears 11 and 12 arranged in the axial direction. The planetary gears 21 and 22 have different numbers of teeth, and the planetary gear 21 is supported by the shaft 41 and the planetary gear 22 by the shaft 42 with respect to the carrier 4 integrally provided with the output shaft 5. Although the 21 and 22 individually rotate about the input shaft 60 and the output shaft 5 which are coaxially arranged in the rotational direction, they perform the same revolution. And two ring gears 31, which are arranged concentrically with the input shaft 60 and are arranged in the axial direction,
Of the 32, the ring gear 31 meshes with the planetary gear 21, and the ring gear 32 meshes with the planetary gear 22.

In the transmission using this planetary mechanism, gear shifting is performed by changing one of the two ring gears 31 and 32, which are both freely rotatable, from a fixed state to the other fixed state. be able to. Reference numeral 70 in the figure denotes a switching member that selectively fixes the ring gears 31 and 32. The switching member 70 that is slidable in the axial direction of the planetary mechanism is moved by the sliding operation.
The state in which the ring gear 31 is engaged with the engagement protrusion 35 on the outer peripheral surface to stop the rotation of the ring gear 31, and the engagement protrusion 36 on the outer peripheral surface of the ring gear 32
, And the state in which the rotation of the ring gear 32 is stopped is switched.

When the rotation of the ring gear 31 is stopped, the deceleration output can be taken out to the output shaft 5 via the sun gear 11, the planetary gear 21, the ring gear 31, and the carrier 4. At this time, the ring gear 32 runs idle. To do. When the rotation of the ring gear 32 is stopped, the deceleration output can be taken out to the output shaft 5 via the sun gear 12, the planetary gear 22, the ring gear 32, and the carrier 4, and at this time, the ring gear 31 idles. In the illustrated example, 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, so that the former outputs a high-speed low-torque output and the latter outputs a low-speed output. A high rotation torque output can be obtained.

Here, it is assumed that the switching member 70 that shifts gears by the sliding operation slides when driven by the keep solenoid 7. This keep solenoid 7
Is a type that can hold the plunger 74 in the attracted state by the permanent magnet M and can almost cancel the magnetic force of the permanent magnet M when excited with the opposite polarity. A switching member 70 is attached. Further, a compression coil spring type spring 75 is attached to the plunger 74 in a state where the initial spring force a is set, and the plunger 74 is attracted by the distance x and attracted by the magnetic force of the permanent magnet M. At this time, when excited with the opposite polarity, the spring force a + kx (k: spring constant)
It is designed to be pulled out by.

Now, as shown in FIG. 37, when the plunger 74 is attracted and this state is maintained by the non-excited attraction force fm (fm> spring force a + kx) due to the permanent magnet M, Since the switching member 70 fixes the ring gear 31, it is in a high-speed rotation output state. At this time, if a reverse polarity current is momentarily applied to the keep solenoid 7, the magnetic force of the permanent magnet M is canceled by the reverse excitation and the plunger 74 is pulled out by the spring force a + kx. Slide to the position where the rotation is stopped, and make the output slower after that. At this position, the magnetic force of the permanent magnet M with respect to the plunger 74 becomes substantially zero, so that this state is maintained by the spring force a. Then, when the keep solenoid 7 is momentarily excited in the state of low speed rotation output, the exciting attraction force fc, which is greater than the spring force a, attracts the plunger 74 and the switching member 70 is engaged with the ring gear 31. This state is maintained by the non-excited attraction force fm due to the permanent magnet M even if it is not excited afterwards.

In any of the switching operations, when the switching operation is completed, the non-excited attraction force f generated by the permanent magnet M is generated.
Since the state is maintained by m or the spring force a, at the time of switching, it suffices to instantaneously flow a current having a polarity corresponding to the switching direction to the keep solenoid 7.
The current consumption is extremely small as compared with the case of using an ordinary solenoid that must keep the current flowing to maintain the attracted state of the plunger 74.

[0011]

However, since the transition from the high reduction ratio state to the reduced speed ratio state is assisted by the spring force a + kx, it is possible with a small exciting force, but from the reduced speed ratio state to the high state. The switching to the reduction ratio state, that is, the operation of retracting the plunger 74 requires an exciting attraction force that exceeds the spring force a, and the exciting attraction force that acts on the plunger 74 depends on the amount of protrusion of the secondary force. Since it decreases functionally, it cannot be restored without using a very large keep solenoid, and there is a problem in this point when it is adopted in a portable power tool.

The present invention has been made in view of the above circumstances. An object of the present invention is to reduce the power consumption required for gear shifting in order to perform gear shifting using a keep solenoid, and also to use the keep solenoid as a keep solenoid. It is an object of the present invention to provide a transmission that can use a small one.

[0013]

SUMMARY OF THE INVENTION The present invention, however, includes a gear shift mechanism portion, a switching member for causing the gear shift mechanism portion to shift gears, an electromagnetic drive member for driving the switching member, and a keep solenoid. The electromagnetic drive member that is driven from the reduced speed ratio state to the high reduction ratio state is characterized in that the return from the high reduction ratio state to the reduced speed ratio state is performed by manual input. There is.

In the case of a transmission for a power tool, the electromagnetic drive member operates in response to changes in the load state during work,
It is preferable to recover by manual input at the end of work or at the start of the next work, for example, by operation input of a trigger switch for power source control. Further, it is preferable that the keep solenoid, which is an electromagnetic drive member, returns by pulling the plunger by the movement of the main body side having the drive coil.

In the case of a transmission for a power tool, the transmission mechanism shifts with an electromagnetically driven member that operates in response to changes in the load during work, and is restored by manual input at the start of the next work, for example, It is advisable to recover by operating the trigger switch for power source control. The electromagnetic drive member may be restored by the operation input of the trigger switch, but may be restored by the return of the trigger switch. In the latter case, it is preferable that the keep solenoid, which is an electromagnetic drive member, returns by pulling the plunger by the movement of the main body side having the drive coil.

A hook and a spring, a permanent magnet, a cam, a differential gear mechanism, or the like can be used as the linking member between the electromagnetic drive member and the trigger switch. It is desirable that a spring be interposed between the electromagnetic drive member and the switching member. Further, when the main body of the electromagnetic drive member is slidably moved, it is preferable that the housing in which the electromagnetic drive member is housed is provided with ribs and guide pins for guiding the sliding movement. The electromagnetic drive member may be attached via a holding base which is a molded product.

Further, when returning by the operation input of the trigger switch, a guide member for guiding the sliding movement of the trigger switch is also provided, and the guide member is formed as a sliding contact portion between pins or a ball and a ball. It is good to put it. According to the present invention, since the electromagnetic driving force for returning is unnecessary, as the keep solenoid,
It is possible to use one that has only a small electromagnetic driving force.

In the case of a transmission for a power tool, the transmission mechanism changes gears with an electromagnetically driven member that operates in response to changes in the load during work, and is restored by manual input at the start of the next work, for example, If the operation source of the power source control trigger switch is used for restoration, the restoration can be facilitated and the work can always be started from the high speed rotation state of the reduced speed ratio.

The electromagnetic drive member can be restored by the operation input of the trigger switch, or can be restored by the return of the trigger switch. In the latter case,
If the keep solenoid, which is an electromagnetic drive member, returns by pulling the plunger by the movement of the main body side having the drive coil, the return operation by manual input of the electromagnetic drive member can be easily performed.

If a spring is interposed between the electromagnetic drive member and the switching member, the return operation of the transmission mechanism can be made smoother and more reliable. Further, when the main body of the electromagnetic driving member is slidably moved, if the rib or the guide pin for guiding the sliding movement is provided in the housing, the inclination of the electromagnetic driving member can be prevented. If the electromagnetic drive member is attached via a holding base that is a molded product, it is possible to easily interlock with a trigger switch and the like.

Further, in the case of returning by the operation input of the trigger switch, a guide member for guiding the sliding movement of the trigger switch is also provided, and the guide member is formed as a sliding contact portion between pins or a ball and a ball. When set, the sliding resistance of the trigger switch can be greatly reduced.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The embodiments of the present invention will be described in detail below with reference to the illustrated examples. The electric tool shown in FIG. 4 is an electric drill driver.
First, the power transmission mechanism and the speed change mechanism from the to the chuck 50 will be described. As shown in FIG. 5, the output shaft 60 of the motor 6 arranged on the one end opening side of the gear case 1 has two different numbers of teeth. Two sun gears 11 and 12 are fixed to each other, and a plurality of planet gears 21 and 22 are engaged with the sun gears 11 and 12, which are arranged in the axial direction, respectively. Both planetary gears 21, which have different numbers of teeth,
22 are both supported by the carrier 4, and the planetary gears 21 are equally spaced around the sun gear 11 and are connected to the planetary gears 2.
The two gears 2 are supported around the sun gear 12 at equal intervals, and both planet gears 21 and 22 perform the same orbital rotation, although they individually rotate.

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 3 on its outer peripheral surface as shown in FIGS. 9 and 12.
Numerals 5 are formed at equal intervals in the circumferential direction, and are freely rotatable with respect to the gear case 1. The ring gear 32 is also freely rotatable with respect to the gear case 1, and the ring gear 32 also serves as the inner race 331 of the one-way clutch 33 having the gear case 1 as the outer race 330. ing.

The one-way clutch 33 here is
As described above, the gear case 1 is the outer race 330, the ring gear 32 is the inner race 331,
A free wheel type formed by arranging balls (or rollers) 332 in a wedge-shaped space formed between 0 and 331. As shown in FIGS. The drive piece 77 provided with a wedge-shaped space and protruding from the forward / reverse switching ring 76 is located between the two types of wedge-shaped spaces, and the forward / reverse switching ring 76 is rotated with respect to the gear case 1 to drive the drive piece. Any one of the pair of balls 332, 332 located on both sides of 77 is the driving piece 7.
It is possible to switch the rotatable direction of the ring gear 32, which is the inner race 331, depending on whether the ring gear 32 is pressed with 7.

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. 13, the other ball 332 is positioned in the narrow portion of the wedge-shaped space by being biased by the spring 333. In this state, the ring gear 32 (inner race 331) in the direction of arrow A in the figure can rotate, but the ring gear 32 in the direction of arrow B in the figure can rotate.
Rotation is blocked. When pushing the ball 332 on the right side in the figure to the right side in the figure by the drive piece 77, the arrow B in the figure is turned on the contrary.
The ring gear 32 (inner race 331) can rotate in the direction A, and the ring gear 32 in the direction A can be prevented from rotating.

In addition to the planetary mechanism, the forward / reverse switching ring 76 and the one-way clutch 33, a ring-shaped switching member 70 is arranged in the gear case 1. The switching member 70 that is slidable in the axial direction is shown in FIGS.
As shown in 2, when the ring gear 31 moves in one direction.
A protrusion 71 that engages with the engagement protrusion 35 on the outer peripheral surface is provided. The engagement prevents the ring gear 31 from rotating, and the engagement protrusion 35 and the protrusion 71 are engaged by sliding the ring gear 31. When released, the ring gear 31 is allowed to rotate. The switching member 70 including the protrusion 71 is shown in FIG.
As shown in FIG. 7, it is preferable that the side surface of the protrusion 71 is provided with a flange 70a integrally connected from the viewpoint of strength, and by adopting such a form, the durability against an impact load is significantly improved. You can

The axial slide of the switching member 70 is an electromagnetic drive member 7 which is a keep solenoid shown in FIGS. 12 and 4, and is pivotally supported on the outer surface of the gear case 1 by a shaft 66 and one end of which is electromagnetic drive member 7. Further, the other end is made by a lever 65 connected to a connecting shaft 72 protruding from the outer peripheral surface of the switching member 70. This point will be described later in detail.

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. 12 (a), the switching member 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 electromagnetic 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 switching member 70 moves to engage the engaging projections as shown in FIG. 12 (b). When the engagement between the gear 35 and the protrusion 71 is released, the ring gear 31 becomes free and the stop of the carrier 4 connected to the load causes the rotation of the planet gears 21 and 22 meshing with the sun gears 11 and 12 to rotate the ring gears 31 and 32. 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 order to stop the rotation of the ring gear 32 by utilizing the one-way clutch 33, this shift is performed only by separating the switching member 70 from the locking projection 35 of the ring gear 31,
There is no member that causes a collision to prevent the rotation of the ring gear 32. Therefore, although the gear shift is in operation, the gear shift can be performed smoothly and without noise. 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 electromagnetic drive member 7. This will be described later.

By rotating the forward / reverse switching ring 76,
When the rotation direction of the one-way clutch 33 is reversed and the rotation direction of the motor 6 is reversed,
Power is transmitted to the carrier 4 through the planetary gears 21 meshing with the ring gear 31 whose rotation is stopped by the switching member 70. At this time, the ring gear 32 idles in the rotatable direction of the one-way clutch 33. When the electromagnetic drive member 7 is activated and the ring gear 31 becomes free upon detection of an increase in load, 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. To be done. 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 shown in FIG. 14, and one end of the rotation direction switching rod 8 is pivotally 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. 4, and the rotation direction of the motor 6 is switched at the same time. The switch unit SW controls the energization of the motor 6 when the trigger switch 9 is pulled, and the trigger switch 9
Although the rotation speed control of the motor 6 is also performed according to the amount by which is subtracted, description of this point will be omitted.

6 to 11 show the order of assembling the respective parts into the gear case 1. After mounting the switching lever 90 and the lid member 10, the forward / reverse switching ring 76 is mounted as shown in FIG. And the carrier 4, and then, as shown in FIG. 8, 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. 9, and the switching as shown in FIG. After the members 70 are stored in order, the thrust plate 19 is mounted and assembled as shown in FIG. The protrusion 13 in the drawing has a ring gear in order to secure a working space for the forward / reverse switching ring 76 and eliminate sliding resistance between the forward / reverse switching ring 76 and the ring gear 32 to reduce mechanical loss. It functions as a thrust receiving surface of the gear case 32 and is integrally formed with the lid member 10 fitted to 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.

As shown in FIG. 11, the thrust plate 19 has an outer diameter substantially equal to the inner diameter of the gear case 1, and as shown in FIG. An elastic bending piece 190 that contacts the inner surface is provided on the outer edge and is attached to the gear case 1 by light press-fitting. Therefore, the thrust plate 19 itself is prevented from coming off and the gear block in the gear case 1 is prevented from coming off. Has been. The elastic bending piece 190 also regulates the movement of the forward / reverse switching ring 76 in the thrust direction, and prevents contact interference between the forward / reverse switching ring 76 and the ring gear 32. That is, the thrust surface sliding resistance when the ring gear 32 rotates is reduced.

Next, the operation of the electromagnetic drive member 7, which is a keep solenoid, in particular, the return operation will be described with reference to FIGS. As described above, the electromagnetic drive member 7 operates when the load detected by the rotation speed detection means of the motor 6 increases and causes the plunger 74 to project, and also returns in association with the operation of the trigger switch 9. It is arranged so as to be slidable in the same direction as the operation direction of the trigger switch 9, and when the motor 6 is off, that is, when the trigger switch 9 is not pulled,
As shown in FIG. 1 (a), the trigger switch 9 is in a forward position and the plunger 74 is in a retracted state.
Is not engaged with the ring gear 31, and is set to the low speed rotation high torque state L.

When the trigger switch 9 is pulled from this state, as shown in FIGS. 1 (b) and 1 (c), the electromagnetic drive member 7
Is pushed back by the spring 93 arranged between the trigger switch 9 and the trigger switch 9. By this retreat, the switching member 70 is moved via the lever 65 to be engaged with the ring gear 31, and the high speed rotation low torque state H is set. Trigger switch 9
The switch unit SW starts to energize the motor 6 by pulling, but due to the play Z provided between the trigger switch 9 and the switch unit SW, the energization of the motor 6 becomes the high-speed rotation low torque state H. Started after being set.

When the electromagnetic drive member 7 operates due to the increased load, the plunger 74 projects and the transmission mechanism is switched to the low speed rotation high torque state L, as shown in FIG. 2 (a). When the work is completed and the finger is released from the trigger switch 9, the motor 6 is stopped with the return of the trigger switch 9 by the spring force FT of the return spring 94 and the spring force FX of the spring 93, and then the hook of the trigger switch 9 is hooked. The electromagnetic drive member 7 advances by being pulled by 95, and by this advance, the plunger 74 is drawn into the main body side of the electromagnetic drive member 7 provided with the coil, and returns to the state shown in FIG. The electromagnetic drive member 7 is returned along with the return of the trigger switch 9, and the low speed rotation high torque state L in the transmission mechanism is returned to the high speed rotation low torque state H when the trigger switch 9 is pulled. That is why. The spring force F _T of the return spring 94 and the spring 93 are shown in FIG.
Shows the spring force F _X, the spring force F _P of the spring 75 of the electromagnetic drive member 7, the relationship F _S. 1a, 1b, 1c, 2 in the figure
a and 2b correspond to FIGS. 1 (a) (b) (c) and FIGS. 2 (a) (b), respectively.

Another example is shown in FIGS. Here, the electromagnetic drive member 7 is fixed and its plunger 74
And the trigger switch 9 have a permanent magnet 9 attracted to each other.
6,97 are provided. In the initial state shown in FIG. 15 (a), the plunger 74 of the electromagnetic drive member 7 is in a protruding state, and the transmission mechanism has a low speed rotation and high torque state L.
Is set to From this state, trigger switch 9
15b, the permanent magnets 96, 9 are pulled out as shown in FIG.
Since the plungers 7 are attracted to each other, the plunger 74 is also retracted, the electromagnetic drive member 7 is returned, and the transmission mechanism is switched to the high speed rotation low torque state H.
When the trigger switch 9 is further pulled as shown in (a), energization of the motor 6 is started, and at this time, the permanent magnets 96 and 97 are separated.

When the electromagnetic drive member 7 operates due to the increased load, the plunger 74 projects and the transmission mechanism is switched to the low speed rotation high torque state L as shown in FIG. 16 (b). When the work is completed and the finger is released from the trigger switch 9, the motor 6 is stopped as shown in FIG. 17 (a) as the trigger switch 9 returns, and then the trigger switch 9 is released as shown in FIG. 17 (b). 9 and the plunger 74 are again connected by the permanent magnets 96 and 97.

In this device, the pulling operation of the trigger switch 9 causes the electromagnetic drive member 7 to be restored, and at the same time, the low-speed rotation high-torque state L in the speed change mechanism portion to be returned to the high-speed rotation low-torque state H. is there.
FIG. 18 shows the magnetic attraction force F between the permanent magnets 96 and 97.
The relationship between _M , the spring force F _T of the return spring 94, and the spring forces F _P and F _S of the spring 75 of the electromagnetic drive member 7 is shown. 15 in the figure
a, 15b, 16a, 16b, 17a and 17b are shown in FIG.
These correspond to (a) and (b), FIGS. 16 (a) and (b), and FIGS. 17 (a) and (b), respectively.

19 to 22 show still another example. The electromagnetic drive member 7 in this example is also fixed, and the plunger 74 and the trigger switch 9 are linked to each other. Here, the cam 98 is swingable with respect to the trigger switch 9 and biased by the springs 99a and 99b. Is provided. In the initial state shown in FIG. 20 (a), the plunger 74 of the electromagnetic drive member 7 is in a protruding state, and the speed change mechanism unit is set to the low speed rotation high torque state L. If the trigger switch 9 is pulled from this state, as shown in FIG. 20 (b), the plunger 74 is pushed back by the cam 98, the electromagnetic drive member 7 is returned, and the transmission mechanism section rotates at high speed. Switched to torque state H,
If the trigger switch 9 is pulled further, the state shown in FIG.
As shown in FIG. 1 (b), the cam 98 once falls against the spring 99a, then comes out of the engagement state with the plunger 74, and the energization of the motor 6 is started.

When the electromagnetic drive member 7 operates due to the increased load, the plunger 74 projects and the transmission mechanism is switched to the low speed rotation high torque state L as shown in FIG. 22 (a). When the work is completed and the finger is released from the trigger switch 9, the cam switch 98 and the plunger 74 return to a state of being engaged again with each other as shown in FIGS. Along with the motor 6
Stops. Also in this one, the trigger switch 9
The pulling operation causes the electromagnetic drive member 7 to be returned, and at the same time, the low-speed rotation high-torque state L in the speed change mechanism unit to be returned to the high-speed rotation low-torque state H.

23 to 25 show another example. The electromagnetic drive member 7 shown here is slidably arranged similarly to the electromagnetic drive member 7 in the example shown in FIG. 1, and a rack 100 is provided on the side surface thereof. A rack 101 facing the rack 100 is slidably arranged. On the other hand, the trigger switch 9 has a pair of protrusions 1 for driving a slider 103 that supports a pinion 102 that meshes with both racks 100 and 101 at the same time.
04a and 104b and a projection 105 for sliding the rack 101 are provided.

In the initial state shown in FIG. 24 (a), the electromagnetic drive member 7 is in the advanced position and the plunger 74 is retracted, and the transmission mechanism is set to the low speed rotation high torque state L. There is. When the trigger switch 9 is pulled from this state, as shown in FIG. 24 (b), the trigger switch 9 is retracted by the amount of play between the protrusions 104a and 104b and the slider 103, and then the slider 104 is pushed by the protrusion 104a. Retreat, at this time, Figure 24
As shown in (c), the racks 100 and 101 meshing with the pinion 102 are also both initially retracted so that the speed change mechanism is set to the high-speed rotation low torque state H, and the energization of the motor 6 is started. It If the trigger switch 9 is further pulled from this state, the rack 101 further retracts.

When the electromagnetic drive member 7 operates due to the increased load, the plunger 74 projects and the transmission mechanism is switched to the low speed rotation high torque state L as shown in FIG. 25 (a). When the work is completed and the finger is released from the trigger switch 9, the rack 101 pushed by the projection 105 first advances as the trigger switch 9 returns,
The motor 6 stops at the position where the rack 101 is aligned with the rack 100 as shown in FIG. Protrusion 1 from this position
Since 04b pushes the slider 103 and the rack 101 is pushed by the projection 105, the pinion 102 of the slider 103 advances the rack 100 and returns to the state shown in FIG. 25 (c). It is drawn into the electromagnetic drive member 7. The electromagnetic drive member 7 is returned along with the return of the trigger switch 9, and the low speed rotation high torque state L in the transmission mechanism is returned to the high speed rotation low torque state H when the trigger switch 9 is pulled.

By the way, returning the transmission mechanism from the low speed high torque state L to the high speed low torque state H means engaging the switching member 70 with the ring gear 31 as described above. In this case, Depending on the rotational position of the ring gear 31, the projection 71 of the switching member 70 may be the ring gear 31.
The movement of the switching member 70 may be hindered by hitting the engaging projection 35 of the above. For this reason, the engaging portion between the plunger 74 of the electromagnetic drive member 7 and the lever 65 whose one end is engaged with the switching member 70 has a play in the axial direction of the plunger 74 as shown in FIG. In addition, the spring 110 is provided in the engaged state with the spring 110 interposed.

As shown in FIG. 27 (a), when the switching member 70 is not engaged with the ring gear 31 and the lever 65 is actuated to move the switching member 70 to the ring gear 31 side, FIG. As shown in (b), when the movement of the switching member 70 is hindered by the contact between the protrusion 71 and the engaging protrusion 35, the spring 110 is compressed, and if the ring gear 31 starts to rotate by energizing the motor 6. As shown in FIG. 27 (c), the switching member 70 moves toward the ring gear 31 side via the lever 65 by the spring force of the spring 110, and the rotation of the ring gear 31 is blocked.

Accordingly, in each of the above examples, when the trigger switch 9 is pulled, the transmission mechanism is returned from the low speed high torque state L to the high speed low torque state H to start energizing the motor 6. Although the power is applied earlier, the power supply to the motor 6 may be applied first. However, in this case, abnormal noise may occur due to the collision between the protrusion 71 and the engagement protrusion 35.

Further, as an operation input for returning, the trigger switch 9 is used in each of the above examples so that the work can be always performed in the high speed rotation and low torque state H at the start of the work. The same can be done by using the operation of pressing the bit attached to the work target. When the bit is pressed against the work target, the output shaft 5 is made to retreat against the spring bias, and the retraction of the output shaft 5 is used to restore the electromagnetic drive member 7.

FIG. 28 shows the one-way clutch 33 having an improved assembling property. That is, a pair of balls (rollers) 332 and 332 located on both sides of the drive piece 77 of the forward / reverse switching ring 76 and springs 333, 33 for biasing.
3 and 3 are surrounded by a holding spring 334 which is U-shaped and both ends of which are locked to the drive piece 77, so that a pair of balls (rollers) 332, 332 and biasing springs 333, 333 are assembled at the time of assembling them. It can be handled as an integral part of the forward / reverse switching ring 76 provided with the driving piece 77. Further, the drive piece 77 and the holding spring 334 have
The protrusions 770 and 335 that limit the amount of movement of the ball (roller) 332 in the direction of compressing the spring 333.
Is provided. The spring 3 by the ball (roller) 332.
Since the state in which 33 is extremely compressed can be avoided, the life of the spring 333 can be extended, and at the same time the degree of freedom in designing the spring 333 is increased.

29 to 32 show that the electromagnetic drive member 7 in the case of the embodiment shown in FIG. 1 is supported through the holding table 200. Holding table 2 here
00 has a hook 201 for fixing the electromagnetic drive member 7 when the electromagnetic drive member 7 is fitted in the recess, and a plurality of guide projections 202 projecting to both sides, and one end thereof is connected to the trigger switch 9. A holding base 200 to which the hook 95 and the spring 93 are attached and which is mounted with the electromagnetic drive member 7 and slides together with the electromagnetic drive member 7.
Is provided so that other members and the electromagnetic driving member 7 can be easily interlocked with each other. Further, as shown in FIG.
By locating the guide protrusion 202 between the ribs 210, 210 of the strip, the movement when the electromagnetic drive member 7 itself slides is eliminated and the movement is made smooth.

Regarding the slide guide of the electromagnetic drive member 7 and the holding table 200, as shown in FIGS. 33 and 34,
A guide pin 205 may be provided inside the housing of the electric tool, and the guide protrusion 202 may be in sliding contact with the guide pin 205. Reference numeral 206 in the drawing denotes a rib that projects toward the inner surface of the housing and supports the guide pin 205.

In FIG. 33, a guide pin 207 for smoothing the sliding operation of the trigger switch 9 is also provided, and a pin (or ball) 208 arranged on the trigger switch 9 is slidably contacted with this guide pin 207. ing. As shown in FIG. 31, an oil-impregnated felt collar 220 or a resin collar 221 is arranged on the protrusion of the plunger 74 of the electromagnetic drive member 7 to prevent foreign matter from entering the electromagnetic drive member 7. This is preferable from the viewpoint of preventing the functional deterioration of the electromagnetic drive member 7.

[0055]

As described above, in the present invention, since the return of the electromagnetic drive member from the high reduction ratio state to the reduced speed ratio state is performed by manual input, the electromagnetic drive force for the return is set. This is unnecessary, and for this reason, it is possible to use a keep solenoid having only a small electromagnetic driving force, which is a great advantage when it is adopted in a portable power tool.

If the transmission is for a power tool,
The speed change mechanism is operated by an electromagnetic drive member that operates in response to changes in the load during work, and is returned by manual input at the end of work or at the start of the next work, such as operation of a trigger switch for power source control. If it is assumed that the operation is to be resumed by input, it does not require a dedicated operation input for restoration, and it is easy to restore. Moreover, work with an electric tool must always be started from a high-speed rotation low torque state with a reduced speed ratio. It will be convenient and convenient for work.

Further, when the electromagnetic drive member itself is returned by the return of the trigger switch, the force for returning the electromagnetic drive member becomes unnecessary as an operating force, and particularly the electromagnetic drive member. If the keep solenoid is designed to perform the return by pulling the plunger by the movement of the main body having the drive coil, the structure for returning the electromagnetic drive member becomes simple and the return operation can be easily performed. Becomes

Furthermore, when a spring is interposed between the electromagnetic drive member and the switching member, the returning operation of the speed change mechanism can be made smoother and more reliable, and good operation can be obtained. Further, when the main body of the electromagnetic drive member is slidably moved, if a rib or a guide pin for guiding the sliding movement is provided in the housing, the inclination of the electromagnetic drive member can be prevented and a light and reliable operation can be obtained. be able to. If the electromagnetic drive member is attached via a holding base which is a molded product, it can be easily interlocked with a trigger switch or the like.

Further, when returning by the operation input of the trigger switch, a guide member for guiding the sliding movement of the trigger switch is provided, and the guide member is formed as a sliding contact portion between pins or a ball and a ball. If it is set, the sliding resistance of the trigger switch can be significantly reduced, and smooth operation can be obtained even when foreign matter such as dust enters the sliding contact portion.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention, in which (a)
(b) and (c) are operation explanatory views of the trigger switch and the electromagnetic drive member, respectively.

2A and 2B are operation explanatory views of a trigger switch and an electromagnetic drive member, respectively.

FIG. 3 is a time chart showing the relationship of the spring force of the above.

FIG. 4 is a partially cutaway side view of the above.

FIG. 5 is a vertical cross-sectional view of the transmission mechanism portion of the above.

FIG. 6 is a rear view of the above-mentioned gear case and lid member.

FIG. 7 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. 8 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. 9 is a rear view showing a state in which another ring gear and a planetary gear are incorporated in the same gear case.

FIG. 10 is a rear view showing a state in which a locking ring is further incorporated in the above gear case.

FIG. 11 is a rear view showing a state in which a thrust plate is further attached to the above gear case.

FIG. 12 is a perspective view showing the same operation as above, in which (a) is a perspective view showing before shifting and (b) is a perspective view showing after shifting.

FIG. 13 is an explanatory diagram of a rotation direction switching portion of the above one-way clutch.

FIG. 14 is a cross-sectional view showing a rotation direction switching operation unit of the above.

15A and 15B show another example, and FIGS. 15A and 15B are operation explanatory diagrams respectively.

16 (a) and 16 (b) are diagrams for explaining the above operation.

17 (a) and 17 (b) are operation explanatory views of the above.

FIG. 18 is a time chart showing the relationship between the spring force and the magnetic force of the above.

FIG. 19 is a cutaway perspective view of still another example.

20 (a) and (b) are diagrams for explaining the operation of the same.

FIGS. 21 (a) and 21 (b) are diagrams for explaining the operation of the same.

22 (a), (b) and (c) are diagrams for explaining the operation of the same.

FIG. 23 is a perspective view of another example.

24 (a), (b) and (c) are operation explanatory diagrams of the above.

25 (a), (b) and (c) are diagrams for explaining the above operation.

FIG. 26 is a perspective view of an engaging portion between a plunger and a lever.

27 (a), (b) and (c) are explanatory views of the operation of a spring arranged at an engaging portion between a plunger and a lever.

FIG. 28 is a perspective view of another example of the one-way clutch unit.

FIG. 29 is a side view showing an example of a support structure for an electromagnetic drive member.

30A is a plan view of an electromagnetic drive member and a holding table, and FIG. 30B is a front view of the holding table.

FIG. 31 (a) is a plan view of an electromagnetic drive member, and FIG. 31 (b) is a front view.

FIG. 32 is a sectional view of the above.

FIG. 33 is a cutaway side view showing another example of the support structure for the electromagnetic drive member.

FIG. 34 is a sectional view of the above.

FIG. 35 is a perspective view of another example of the switching member.

FIG. 36 is a schematic view of a conventional example.

FIG. 37 is an explanatory diagram of the operation of the above.

[Explanation of symbols]

 7 Electromagnetic drive member 9 Trigger switch

Claims (15)

[Claims] 1. A speed change mechanism unit, a switching member for causing the speed change mechanism unit to perform a speed change, and an electromagnetic drive member for driving the changeover member. The change speed mechanism unit is composed of a keep solenoid and is operated from a reduced speed ratio state to a high speed reduction ratio. The above-mentioned electromagnetic drive member for driving to the state is a transmission in which the return from the high reduction ratio state to the reduced speed ratio state is manually input. 2. A transmission for a power tool, wherein a speed change mechanism is operated by an electromagnetic drive member that operates in response to a change in a load state during work, and a manual input is made at the end of work or at the start of next work. The transmission according to claim 1, wherein the transmission is returned by. 3. The transmission according to claim 1, wherein the manual input is an operation input of a trigger switch for controlling a power source. 4. The transmission according to claim 3, wherein the electromagnetic drive member returns by an operation input of a trigger switch. 5. The transmission according to claim 3, wherein the electromagnetic drive member is returned by returning the trigger switch. 6. The transmission according to claim 5, wherein the keep solenoid, which is an electromagnetic drive member, returns by pulling the plunger by the movement of the main body having the drive coil. 7. The hook and the spring are members for linking the electromagnetic drive member and the trigger switch.
The described transmission. 8. The transmission according to claim 3, wherein the linking member between the electromagnetic drive member and the trigger switch is a permanent magnet. 9. The transmission according to claim 3, wherein the linking member between the electromagnetic drive member and the trigger switch is a cam. 10. The transmission according to claim 3, wherein the linking member between the electromagnetic drive member and the trigger switch is a differential gear mechanism. 11. The transmission according to claim 1, wherein a spring is interposed between the electromagnetic drive member and the switching member. 12. The transmission according to claim 6, wherein the housing in which the electromagnetic drive member is housed is provided with a rib that guides the sliding movement of the main body of the electromagnetic drive member. 13. The transmission according to claim 6, wherein the housing in which the electromagnetic drive member is housed is provided with a guide pin for guiding the sliding movement of the main body of the electromagnetic drive member. 14. The transmission according to claim 6, wherein the electromagnetic drive member is attached via a holding base which is a molded product. 15. A guide member for guiding the sliding movement of the trigger switch is provided, and the guide member is formed as a sliding contact portion between pins or a ball and a ball. Gearbox.