JP3566737B2 - Non-reaction clutch device for electric rotating tools - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a clutch device for an electric rotating tool, and more particularly, when a driven shaft of the electric rotating tool receives a load torque of a certain level or more, this is detected and rotation transmitted from the output shaft of the electric motor to the driven shaft is detected. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch device capable of preventing sudden rebound caused by a force and a clutch adjusting spring and having no impact in a thrust direction.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, there has been known a clutch mechanism configured to detect, when a tightening of a screw or the like is completed and a load torque equal to or more than a predetermined value is applied, to interrupt transmission of output to a driven shaft.
[0003]
As a means for detecting the load torque, an output from the output shaft is transmitted to the driven shaft via a planetary gear mechanism, and when a load torque of a certain level or more is applied to the driven shaft, the internal gear meshes with the planetary gear. There is known a configuration in which the clutch is disengaged and rotates inside the casing, thereby interrupting the transmission of rotational force from the output shaft to the driven shaft (Japanese Patent Application Laid-Open No. 60-16370).
[0004]
However, in the conventional clutch device, in order to lock the internal gear to the casing, a roller is embedded in a part of the internal gear, a steel ball is elastically engaged with the roller, and a load torque exceeding a certain level is applied. When the roller is applied, the roller gets over the steel ball and the transmission of the rotational force to the driven shaft is interrupted. For this reason, when the roller gets over the steel ball, the compression release elasticity of the spring acts on the member that comes into contact with the steel ball and supports it with the elasticity of the spring, and the roller is interposed through the steel ball. Violently collides with the outer surface of the null gear. Then, the impact due to the severe collision is transmitted as vibration in the left-right direction, that is, the horizontal direction, or the up-down direction, that is, the vertical direction of the driven shaft. Was given as a vibration.
[0005]
Further, even in the case of a clutch device in which the internal gear is locked to the casing by elastic clutch engagement of a steel ball, a normal electric rotating tool is more effective than a case where a screw or the like is tightened. When a work of loosening a tightening screw or the like is performed, a high torque rotational force is required. Therefore, if it is attempted to transmit a high torque rotational force to the driven shaft at the time of reverse rotation without changing the spring elasticity for pushing up the steel ball, in order to properly lock this when the internal gear reversely rotates, for example, It is necessary to project the reverse end of the clutch engagement projection at a steeply inclined angle, or to project the reverse end further with it. For this reason, at the time of screw tightening, the steel ball climbed on the projection part jumps over the opposite end part of the projection part after climbing over the projection part and violently collides with the outer surface of the internal gear, and the vibration of the electric rotating tool is caused. This results in an unpleasant impact sound.
[0006]
In such a clutch device using steel balls, immediately after the fastening of the screw or the like is completed, the steel balls bounce over the cam surface at the moment when the steel balls cross over the clutch cam surface provided with the rollers due to the elasticity of the spring. Phenomena. As shown in FIG. 6, for example, the bouncing phenomenon of the steel ball is transmitted as vibration in the transverse direction to the driven shaft and generates a force FL in a loosening direction opposite to the tightening of a screw or the like. Problems arise.
[0007]
Then, during the clutch operation of the clutch device, after the steel ball bounces on the cam surface and then collides violently with the outer surface of the internal gear, a vertical impact vibration is generated on the driven shaft together with the generation of an impact sound. Is transmitted. The vibration and impact sound generated in this way not only gives the operator operating the electric rotating tool a discomfort, but also, especially for semiconductor parts and precision parts for products in which screws or other mounting work is performed. At the time of the screw tightening work for assembling the device, such vibrations and shocks cause destruction of those components, and have a drawback such as the occurrence of defective products which cause malfunctions. In particular, regarding the impact, a causal relationship has been recognized that the vibration causes the product to be out of order.
[0008]
In addition, the vibration generated by the operation of the clutch device shortens the durability of the electric rotary tool, and causes a blur when the screwdriver completes the screw tightening, even if the operator grips the electric rotary tool strongly. Then, the screw that has been tightened is loosened in reverse.
[0009]
Further, the horizontal and vertical shock vibrations transmitted to the driven shaft during the clutch operation cause tendon sheath inflammation and the like for an operator who grips the electric rotating tool for a long time. It also had an adverse effect on the condition.
[0010]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to eliminate the above-mentioned problem, and to improve the shape of the clutch cam surface by using a repulsive force of a spring acting on the clutch cam surface when the clutch operation is performed, thereby causing a sudden collision. Accordingly, it is an object of the present invention to provide a non-reaction clutch device capable of preventing the occurrence of impact vibration or impact noise of an electric rotating tool by being configured to prevent the occurrence of a shock.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a non-reaction clutch device for an electric rotating tool according to the present invention is configured such that a driven shaft as a working shaft is connected to an output shaft of an electric motor via a reduction mechanism, and a predetermined shaft is provided with respect to the driven shaft. A clutch device for an electric rotary tool configured to perform a clutch operation for breaking engagement between the output shaft and the driven shaft when a load torque greater than or equal to a value acts thereon, wherein the clutch device has a spring elasticity in a thrust direction. And a clutch cam surface which comes into contact with the steel ball and whose contact surface protrudes at a predetermined inclination angle to be engaged when the driven shaft rotates, and which comes into contact with the steel ball. Are configured to sequentially project at a required inclination angle at the time of forward rotation of the driven shaft, and thereafter gradually become a gentle inclination angle, and the clutch device is configured to connect the driven shaft to the output shaft of the electric motor via a planetary gear mechanism. Join In a gripping cylindrical casing surrounding the planetary gear mechanism, an internal gear meshing with the planetary gear is rotatably arranged, and a steel ball is provided between the internal gear and the cylindrical casing, The steel ball is held so as to elastically engage the clutch cam surface provided on the internal gear, and the internal gear is stationary in the cylindrical casing at a load torque of a predetermined value or less during the screw tightening operation. The driven shaft protrudes from the outer surface of the closed bottom portion of the internal gear at the required inclination angle in the same direction as the driven shaft in the forward direction at the time of forward rotation, and gradually gradually thereafter. In a non-reaction clutch device of an electric rotating tool provided with a projection as a clutch cam surface configured to have an inclination angle, an outer side of a closed bottom portion of an internal gear. At the time of forward rotation of the driven shaft, sequentially protrudes at the required inclination angle in the same direction as the driven shaft, and then gradually becomes a gentle inclination angle, and the projection part is in the middle of the gently inclined inclination part. It disappears at a constant width along the outer circumference of the internal gear in the same direction as the normal rotation direction of the driven shaft, and forms a step on the gentle slope of the projection, while the hole provided in the cylindrical casing is The steel ball has an almost elliptical shape that can move, and the opening is gradually directed toward the outer peripheral side of the internal gear in the forward rotation direction of the driven shaft, and stops the rotation of the internal gear when the driven shaft rotates in the reverse direction. And a clutch mechanism configured to perform the above operation .
[0014]
Further, at the outer peripheral portion of the internal gear, one end of the coil spring is fixed to a part of the internal gear, and the other end is disposed in contact with the inner surface of the cylindrical casing. A one-way clutch mechanism configured to lock the rotation of the clutch can be provided.
[0016]
[Action]
According to the non-reaction clutch device for an electric rotary tool of the present invention, a steel ball having a spring elasticity in a thrust direction is brought into contact with the steel ball, and a predetermined contact surface is engaged when the driven shaft rotates. A clutch cam surface protruding at an inclination angle, the cam surface contacting the steel ball is sequentially protruded at a required inclination angle when the driven shaft is normally rotated, and then gradually becomes a gentle inclination angle thereafter. With this configuration, it is possible to eliminate the impact vibration and the impact sound when the clutch device is operated, to prevent the occurrence of a defective assembly part due to the vibration and the impact sound of the electric rotating tool, and to operate the electric rotating tool. It is possible to perform safe and appropriate screw tightening without impairing the health of the worker who performs the work.
[0017]
Further, by providing a clutch mechanism that can also prevent reverse rotation of the internal gear, even when the electric motor is reversely rotated, the screw can be removed smoothly with high torque.
[0018]
【Example】
Next, an embodiment of a reactionless clutch device for an electric rotating tool according to the present invention will be described in detail with reference to the accompanying drawings.
[0019]
FIG. 1 is an enlarged cross-sectional view of a main part of a reactionless clutch device according to an embodiment of the present invention. That is, in FIG. 1, reference numeral 12 indicates a planetary gear mechanism. The planetary gear mechanism 12 includes a pinion gear 16 fixed to a tip of an output shaft 14 of an electric motor, a planetary gear 18 meshing with the pinion gear 16, and an internal gear 20 meshing with the planetary gear 18.
[0020]
This internal gear 20 is rotatably mounted in a cylindrical casing 28. As shown in FIG. 2, in the forward rotation of the driven shaft 26, the direction in which the steel ball 30 abuts, that is, in the forward rotation direction of the driven shaft 26, is formed on the outer bottom surface of the closed bottom surface portion 20 a of the internal gear 20. In the same direction as indicated by the arrow R), there is provided a projection 22 projecting at a required inclination angle and thereafter gradually having a gentle inclination angle. The projection 22 has, for example, a portion 22a projecting at a required inclination angle having substantially the same curvature as that of a conventional roller, and a portion 22b having a gentle inclination angle has the entirety of the closed bottom surface portion 20a of the internal gear 20. It is configured to gradually decrease over approximately 1/4 of the circumference.
[0021]
Reference numeral 24 denotes a support shaft that rotatably supports the planetary gear 18, and the support shaft 24 is formed integrally with a driven shaft 26. Therefore, a driver bit or the like for fastening a screw or a bolt is attached to the tip of the driven shaft 26.
[0022]
Reference numeral 28 denotes a cylindrical casing, and a hole 32 for fitting a steel ball 30 is provided on a bottom surface of the cylindrical casing 28 at a position corresponding to the projection 22 provided on the internal gear 20. Is provided. The steel ball 30 is elastically engaged with the protrusion 22 provided on the outer bottom of the internal gear 20 by the sleeve 36 pushed up by the coil spring 34.
[0023]
Further, between the internal gear 20 and the cylindrical casing 28, one end of the coil spring 38 is fixed to a part of the internal gear at the outer peripheral portion of the internal gear, and the other end of the coil spring 38 is connected to the cylindrical casing 28. There is provided a one-way clutch mechanism arranged to abut on the inner side surface and configured to lock the rotation of the internal gear 20 when the driven shaft reversely rotates.
[0024]
In the non-reaction clutch device thus configured, when performing the screw tightening operation, the steel ball 30 and the protrusion 22 are elastically engaged with each other, and the internal gear 20 is locked in the cylindrical casing 28. Therefore, the rotational force transmitted via the output shaft 14 is transmitted to the planetary gear 18 via the pinion gear 16, and is formed integrally with the support shaft 24 so that the planetary gear 18 revolves while rotating. The driven shaft 26 is rotated to perform a screw or bolt tightening operation.
[0025]
When the tightening operation of the screw or the like is completed, the rotational movement of the driven shaft 26 is stopped and fixed, so that the rotational force transmitted from the output shaft 14 is transmitted to the internal gear 20 through the rotation of the pinion gear 18, When the load torque exceeds a predetermined value, the steel ball 30 elastically engaged with the protrusion 22 provided on the outer bottom of the closed bottom surface 20a of the internal gear 20 is pushed down, and the protrusion 22 Gets over the steel ball 30, and the engagement between the protrusion 22 and the steel ball 30 is released. As a result, the internal gear 20 rotates inside the cylindrical casing 28, and transmission of output to the driven shaft 26 is cut off.
[0026]
As described above, when the clutch device according to the present invention operates, the protrusion 22 provided on the outer bottom of the internal gear 20 has a required direction in the same direction as the forward rotation of the driven shaft as shown in FIG. Since it has a stepless structure of projecting at an inclination angle and having a gradual inclination angle gradually thereafter, when the depressed steel ball 30 attempts to return to the original position, the outer bottom portion of the internal gear 20 is closed. There is no sudden collision. As described above, since there is no impact caused by the collision of the steel ball 30 with the internal gear, no impact vibration or impact noise is generated on the electric rotary tool.
[0027]
When the screw is removed, the load torque is transmitted to the internal gear 20 in a direction opposite to the direction of the tightening operation. Works with However, when the clutch device operates and the internal gear 20 rotates in the reverse direction, the coil spring 38 provided between the internal gear 20 and the cylindrical casing 28 expands and contacts the cylindrical casing 28 to reduce frictional resistance. As a result, the rotation of the internal gear 20 is stopped. That is, an operation as a one-way clutch mechanism is performed. Therefore, a high torque rotational force is transmitted to the driven shaft 26.
[0028]
FIG. 3 is a perspective view of the internal gear 20 showing a modified example of the internal gear reverse rotation prevention mechanism. That is, in FIG. 3, the projection 22 has a portion 22 a that projects at a required inclination angle in the same direction as the forward rotation direction of the driven shaft 26 (indicated by an arrow R), and then gradually becomes a gentle inclination angle. And the projection 22 disappears at a constant width along the outer circumference of the internal gear in the same direction as the forward rotation of the driven shaft from the middle of the gently inclined inclined portion, and the projection is gradually inclined. The surface has a step 22c.
[0029]
FIG. 4 is a perspective view of a cylindrical casing 28 that is compatible with the internal gear 20 shown in FIG. In FIG. 4, the hole for fitting the steel ball 30 provided in the cylindrical casing 28 is formed as a substantially elliptical opening 32 a in which the steel ball 30 can move, and the opening 32 a is formed in the driven shaft 26. It is formed so as to be gradually directed toward the outer peripheral side with respect to the normal rotation direction, that is, the reverse rotation direction of the internal gear 20. In this case, it is preferable that the opening 32a has a slightly bent shape as shown in the figure. With this configuration, when the driven shaft 26 rotates forward, the steel ball 30 moves to the shaft core side portion of the opening 32a with respect to the rotation direction of the internal gear 20 and is stabilized. The gear 20 resiliently engages with the inclined portion 22a. Therefore, the internal gear 20 is clutch-engaged within the cylindrical casing 28.
[0030]
On the other hand, when the screw or the like is loosened, the internal gear 20 tends to rotate in the reverse direction, so that the steel ball 30 that is in contact with the closed bottom surface of the internal gear 20 is located at the edge of the opening 32a. Along with the outer peripheral side of the internal gear 20, whereby the steel ball 30 elastically engages with the wall portion 40 provided on the projection 22, so that the steel ball 30 is high even when loosening work such as screws is performed. The torque torque can be transmitted to the driven shaft 26.
[0031]
The wall 40 has a height greater than that at the time of screw tightening work when loosening a screw or the like by setting a steep inclination angle in the forward rotation direction of the driven shaft above the inclined portion 22a of the protrusion 22. The torque can be transmitted to the driven shaft 26.
[0032]
Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment.For example, regarding the shape of the protruding portion, the angle of the inclined portion that the steel ball first comes into contact with at the time of screw tightening is moderate Needless to say, various design changes can be made within a range that does not deviate from the spirit of the present invention.
[0033]
【The invention's effect】
As is clear from the above-described embodiment, according to the non-reaction clutch device of the present invention, basically, the steel ball holding the spring elasticity in the thrust direction comes into contact with the steel ball and the contact surface is driven by the steel ball. A clutch device having a clutch cam surface protruding at a predetermined inclination angle engaged during rotation of the shaft, wherein the cam surface contacting the steel ball sequentially protrudes at a required inclination angle during normal rotation of the driven shaft, After that, by gradually configuring the inclination angle gradually, it is possible to reliably prevent the impact vibration generated during the clutch operation in the conventional electric rotating tool.
[0034]
That is, as a clutch device, for example, a driven shaft is connected to an output shaft of an electric motor via a planetary gear mechanism, and an internal gear that meshes with the planetary gear is provided in a gripping cylindrical casing surrounding the planetary gear mechanism. A steel ball is provided between the internal gear and the cylindrical casing so as to be rotatable, and the steel ball is held so as to elastically engage a clutch cam surface provided on the internal gear. In the above, by providing a projection formed of the clutch cam surface having the above configuration on the outer surface of the closed bottom portion of the internal gear, the lateral vibration generated during the clutch operation in the conventional electric rotating tool is completely removed. It was confirmed that it could be performed (see FIG. 5).
[0035]
Similarly, according to the non-reaction clutch device of the present invention, it is possible to obtain a non-reaction clutch device which can almost completely eliminate vibration in the vertical direction, thereby reliably preventing impact vibration and impact noise. Was completed. Incidentally, as a result of measuring the vibration in the vertical direction, it was confirmed that the device of the present invention can reduce the vibration to about 1/30 as compared with the device of the related art.
[Brief description of the drawings]
FIG. 1 is an enlarged sectional view of a main part showing an embodiment of a non-reaction clutch device for an electric rotary tool according to the present invention.
FIG. 2 is a perspective view of the internal gear, showing an embodiment of a shape of a projection formed on the internal gear;
FIG. 3 is a perspective view of an internal gear showing a modification of the shape of a projection formed on the internal gear.
4 is a perspective view of a cylindrical casing having a hole for fitting a steel ball that fits into a protrusion of the internal gear shown in FIG. 3;
FIG. 5 is a waveform diagram of a left-right shock vibration generated on a driven shaft during a clutch operation of an electric rotating tool including the reactionless clutch device according to the present invention.
FIG. 6 is a waveform diagram of a left-right shock vibration generated on a driven shaft during a clutch operation of an electric rotating tool including a conventional clutch device.
[Explanation of symbols]
12 Planetary Gear Mechanism 14 Output Shaft 16 Pinion Gear 18 Planetary Gear 20 Internal Gear 20a Internal Gear Closed Bottom Surface 22 Projection 22a Projection 22b Projecting at a Required Inclined Angle Part 22c Projecting at a Slight Inclined Angle 22c Step 24 Shaft 26 driven shaft 28 cylindrical casing 30 steel ball 32 hole 32a opening 34 coil spring 36 sleeve 38 coil spring 40 wall

Claims (2)

A driven shaft as a working shaft is connected to the output shaft of the electric motor via a speed reduction mechanism, and when a load torque of a predetermined value or more acts on the driven shaft, the output shaft and the driven shaft are engaged. A clutch device of an electric rotary tool configured to perform a clutch operation for breaking, wherein the clutch device is a steel ball having a spring elasticity held in a thrust direction and the steel ball is in contact with a driven shaft. A clutch cam surface protruding at a predetermined inclination angle that engages during rotation of the driven shaft. The cam surface abutting the steel ball sequentially protrudes at a required inclination angle when the driven shaft rotates in the forward direction, and gradually gradually thereafter. The clutch device is configured to have an inclination angle , and the clutch device is configured such that a driven shaft is coupled to an output shaft of the electric motor via a planetary gear mechanism, and the planetary gear and the gripping portion are enclosed in a gripping cylindrical casing surrounding the planetary gear mechanism. Bite The internal gear is rotatably arranged, a steel ball is provided between the internal gear and the cylindrical casing, and the steel ball is elastically engaged with a clutch cam surface provided on the internal gear. The internal gear is configured to be held stationary in the cylindrical casing at a load torque of a predetermined value or less during the screwing operation, and the outer surface of the closed bottom portion of the internal gear is held. In addition, when the driven shaft rotates in the forward direction, the driven shaft protrudes in the same direction in the same direction at a required inclination angle, and thereafter has a projection as a clutch cam surface configured to have a gradually gradual inclination angle. In the non-reaction clutch device of the tool,
The projection provided on the outer surface of the closed bottom portion of the internal gear projects at the required inclination angle in the same direction as the driven shaft when the driven shaft is normally rotating, and then gradually becomes a gentle inclination angle. Disappears at a constant width along the outer circumference of the internal gear in the same direction as the normal rotation direction of the driven shaft from the middle of the gently inclined part, and forms a step on the gently inclined surface of the projection, while the cylinder The hole provided in the casing has a substantially elliptical shape in which a steel ball is movable, and is opened so as to gradually face the outer peripheral side of the internal gear with respect to the normal rotation direction of the driven shaft. A non-reaction clutch device for an electric rotary tool , comprising a clutch mechanism configured to stop rotation of an internal gear during reverse rotation . At the outer peripheral portion of the internal gear, one end of the coil spring is fixed to a part of the internal gear, and the other end is disposed in contact with the inner surface of the cylindrical casing, so that when the driven shaft rotates in reverse, the internal gear rotates. recoilless clutch unit for an electric rotary tool formed by providing a one-way clutch mechanism configured to lock according to claim 1, wherein the.

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