JPH0579103U - Worm gearing - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to prevent overloading of worm transmissions. [Structure] Drive motor 3 fixed to motor mounting member 4
Of the worm 2, which is fixed coaxially with the drive shaft 3a, the worm wheel 1 that meshes with the worm 2 to rotate, and the support shaft 5 that rotatably supports the motor mounting member 4 as a central axis. A worm transmission device 10 including a pressing means 6 for pressing the worm 2 against the worm wheel 1 to engage with the worm wheel 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a worm power transmission device, and more particularly to a worm power transmission device provided with an overload prevention mechanism.

[0002]

[Prior Art]

 As one means for transmitting the rotational movement, there is a worm transmission composed of a worm and a worm wheel.

The worm of this worm transmission is a gear having a shape similar to that of a multiple thread screw, and the worm wheel is a gear that meshes with the worm. The worm has a very large number of teeth, and the teeth and grooves are It has a recessed shape and meshes in a posture of holding a worm. The meshed worm wheel and the transmission axis of the worm form a right angle.

A worm transmission in which a worm wheel and a worm are meshed with each other is a worm that is a driving side and a worm that is a driven side under the condition that the advance angle of the worm is not larger than the friction angle of the tooth surface contact. While the wheel can be driven and the rotational movement can be transmitted only in one direction, the worm wheel that is the driven side cannot drive the worm that is the driven side. Therefore, the stop position of the worm wheel on the driven side can be controlled only by the worm on the drive side, and the worm can maintain the stopped position even if external force is applied to the worm wheel. is there.

[0005]

[Problems to be solved by the device]

 The worm transmission has the characteristics described above, but on the other hand, if the driven side is to be inspected independently at the time of equipment maintenance inspection, the driven side cannot be moved unless the worm is rotated. There was a problem that the mesh of the worm had to be disassembled and released.

[0006]

[Means for Solving the Problems]

 The present invention has been made to solve the above problems, and includes a worm fixed coaxially to a drive shaft of a drive motor fixed to a motor mounting member, and a worm wheel rotating in mesh with the worm. A pressing means that presses the worm against the worm wheel to engage the worm with a support shaft that rotatably supports the motor mounting member as a central axis. When the worm wheel is overloaded, the pressing means It is an object of the present invention to provide a worm transmission characterized in that the meshing of the worm and the worm wheel is released against the pressing force.

[0007]

【Example】

 FIG. 1 is an explanatory view of a first embodiment of a worm transmission device of the present invention.

In the figure, 1 is a worm wheel, 2 is a worm, 3 is a drive motor, 4 is a motor mounting member, 5 is a support shaft, 6 is a spring, 7 is a bearing, and 8 is a fixing fitting.

The worm transmission 10 of the present invention fixes a drive motor 3 in which a worm 2 is coaxially connected to a drive shaft 3a to a motor mounting member 4, and the motor mounting member 4 is provided with a support shaft 5 of a fixing bracket 8 therebetween. Is rotatably supported. Further, a spring 6 (pressing means) for pressing the motor mounting member 4 counterclockwise around the support shaft 5 is mounted between the motor mounting member 4 and the fixing metal fitting 8. The worm 2 of the drive shaft of the drive motor 3 mounted on the motor mounting member 4 by the spring 6 is pressed and abuts the bearing 7, and is meshed with the worm wheel 1.

Furthermore, the positional relationship of the support shaft 5 of the fixing metal fitting 8 that supports the motor mounting member 4 will be described.

FIG. 2 is an enlarged view of an essential part showing a force vector applied to the tooth 1 a of the worm wheel 1 and the tooth 2 of the worm 2 which are meshed with each other, which will be described in combination with FIG. 1.

When the drive motor 3 is driven and the worm wheel 1 is about to be rotated in the direction R 1, the contact point P between the tooth 1 a of the worm wheel 1 and the tooth 2 a of the worm 2 contacts the tooth 2 a of the worm 2. Will receive force F. This force F is considered to be the resultant force of the force Fx and the force Fy, and the support shaft 5, which is an essential part of the present invention, is provided on the extension line of the force Fx.

Therefore, the worm 2 receives the moment of the force Fy with the support shaft 5 and the contact point P between the tooth 1a of the worm wheel 1 and the tooth 2a of the worm 2 as a radius. Moreover, even when the worm wheel 1 is rotated in the R2 direction, if the load of the worm wheel 1 is the same, it receives the same moment as in the R1 direction. If the moment at this time is Mw and the moment generated by the spring 6 around the support shaft 5 is Ms, Mw = Ms becomes the limit driving force, and the torque transmission beyond this is shown in FIG. The worm 2 is moved around the support shaft 5 in the M direction, and the meshing with the worm wheel 1 is released.

Further, when an external force is applied to the worm wheel 1 to stop the rotation, Mw> Ms, the meshing is released, the torque transmission is stopped, and the drive motor 3 is protected from burnout due to overload. There is an effect that can be.

Next, the worm transmission 20 of the present invention will be described.

FIG. 3 is an explanatory view of a second embodiment of the worm transmission device of the present invention, and FIGS. 4 and 5 are vectors of the force applied to the teeth 1a of the worm wheel 1 and the teeth 2a of the worm 2 which are engaged with each other. FIG. 2 is an enlarged view of a main part showing the same, and the same components as those of FIG.

The second embodiment of the worm transmission of the present invention is a modification of the position of the support shaft 5 in the first embodiment, and when torque is transmitted from the worm wheel 1 in the R1 direction, as shown in FIG. The worm 2 receives the combined force F1 of the component force Fx1 of the force Fx and the component force Fy1 of the force Fy with the support shaft 5 and the contact point P between the tooth 1a of the worm wheel 1 and the tooth 2a of the worm 2 as a radius. become. If this moment is Mw1 and the moment generated by the panel 6 with the support shaft 5 as the axis is Ms, the worm 2 with the support shaft 5 as the axis in the M direction shown in FIG. 3 under the condition of Mw1> Ms. Moves and the engagement with the worm wheel 1 is released. Similarly, when torque is transmitted from the worm wheel 1 in the R2 direction, as shown in FIG. 4, the force F received by the teeth of the worm 2 causes the support shaft 5 and the contact point P to have a radius F2. Letting this moment be Mw2, if the load of the worm wheel 1 is the same in the rotational directions R1 and R2, the condition of Mw1> Mw2 is satisfied. Therefore, the same load is applied to the worm wheel 1 in the rotational directions R1 and R2. When a load is applied, the worm 2 moves in the M direction shown in Fig. 3 in the R1 direction and the meshing is released to function as overload protection, but it functions as the overload protection in the R2 direction. The condition of Mw2 <Ms <Mw1 is satisfied. Although the position of the support shaft 5 is determined to satisfy this condition, the condition of Mw2> Ms> Mw1 can be set by arbitrarily selecting the position of the support shaft 5.

As described above, the worm transmission of the present invention has the effects of protecting the transmission against overload of the worm wheel and facilitating maintenance and inspection of the transmission.

[0019]

[Effect of the device]

 As described above, the worm transmission of the present invention includes a worm fixed coaxially to the drive shaft of a drive motor fixed to a motor mounting member, a worm wheel that meshes with the worm to rotate, and the motor mounting member. A pressing means for pressing the worm against the worm wheel and engaging the worm with the support shaft that rotatably supports the member as a central axis, and resisting the pressing force of the pressing means when the worm wheel is overloaded. Since the meshing between the worm and the worm wheel described above is released, the effect of protecting the transmission against overload of the worm wheel and facilitating maintenance inspection of the transmission is provided. There is.

[Brief description of drawings]

FIG. 1 is an explanatory view of a first embodiment of a worm transmission device of the present invention.

FIG. 2 is an enlarged view of a main part showing a vector of a force applied to a meshed worm wheel and a tooth of the worm.

FIG. 3 is an explanatory view of a second embodiment of the worm transmission device of the present invention.

FIG. 4 is an enlarged view of an essential part showing a vector of a force applied to a meshed worm wheel and a tooth of the worm.

FIG. 5 is an enlarged view of an essential part showing a vector of forces applied to the meshed worm wheel and the teeth of the worm.

[Explanation of symbols]

 10,20 Worm transmission 1 Worm wheel 1a Worm wheel tooth 2 Worm 2a Worm tooth 3 Drive motor 3a Drive shaft 4 Motor mounting member 5 Spindle 6 Pressing means (spring) 7 Bearing 8 Fixing metal

Claims (1)

[Scope of utility model registration request] 1. A worm fixed coaxially to a drive shaft of a drive motor fixed to a motor mounting member, a worm wheel rotating in mesh with the worm, and a rotatably rotatably supporting the motor mounting member. The worm and the worm wheel against the pressing force of the pressing means when the worm wheel is overloaded. A worm transmission characterized in that it is configured to release the meshing with the.