JP5383835B2 - Gears with which only some of the teeth mesh with each other and its mounting method - Google Patents

Description

  The present invention relates to a gear in which teeth are continuously formed in the circumferential direction, and only some of the teeth mesh with other gears, and a method of attaching the gear.

  For example, an outlet damper of an electric dust collector used in a power plant is driven by a worm gear. That is, a worm wheel (helical gear) is concentrically attached to a damper shaft provided with damper blades via a key, and a worm (screw gear) is provided so as to mesh with the worm wheel. When the worm rotates, the worm wheel rotates, and the damper shaft, that is, the damper blade rotates (opens and closes) with this rotation.

  Some outlet dampers open and close damper blades by 90 degrees. In such a case, the damper shaft also rotates by 90 degrees, and therefore the worm wheel rotates by 90 degrees (forward / reverse). For this reason, the worm wheel meshes with the worm only at the tooth portion corresponding to 90 degrees of rotation. That is, only a part (1/4) of the teeth of the worm wheel formed over the entire length of the outer periphery meshes with the worm.

  Also, a sintered gear with a key groove is known in which a plurality of key grooves are formed in a hole into which the shaft is inserted so that the shaft can be easily assembled or the like (see, for example, Patent Document 1).

JP 2003-028276 A

  By the way, by repeatedly engaging with the worm, the teeth of the worm wheel are worn and deteriorated (broken). When wear or the like progresses, it is necessary to replace the worm wheel with a new worm wheel. At this time, even when only a part of the teeth of the worm wheel meshes with the worm as described above, that is, when only a part of the teeth are worn, the entire worm wheel must be replaced. For this reason, not only is it uneconomical, but when there is no inventory of replacement (new) worm wheels, it takes a long time to replace them, making it difficult to respond quickly. On the other hand, if all the teeth can be used effectively, it is economical and quick response is possible.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a gear that can effectively utilize all teeth and that only some of the teeth mesh with, and a method for attaching the gear.

In order to achieve the above object, according to the first aspect of the present invention, the teeth are formed continuously in the circumferential direction, and only a part of the teeth meshes with another gear by rotating by a predetermined angle. A gear with which only the teeth of the shaft mesh, the gear having a shaft insertion hole and a first key groove formed on an inner peripheral wall of the shaft insertion hole, and a plurality of second key grooves on the outer periphery. And a key that can be inserted into the first key groove and the second key groove, and the second key groove has a predetermined angle so that the gear can be rotated and fixed at predetermined angles. The other gear is formed by changing the fitting position of the first key groove and the second key groove into which the key is inserted by rotating the gear around an axis. It is provided that the teeth meshing with each other are changed.

The invention according to claim 2 is a gear in which teeth are formed continuously in the circumferential direction, and only a part of the teeth meshes with another gear by rotating by a predetermined angle . In the mounting method, a shaft insertion hole and a first key groove formed on an inner peripheral wall of the shaft insertion hole are provided on the gear, and a plurality of second key grooves are provided on an outer periphery of the shaft, and the gear The second keyway is formed at every predetermined angle so that the key can be inserted around the axis by rotating the gear around the axis and the second keyway. By changing the fitting position with the two key grooves, the teeth meshing with the other gears are changed.

According to the first and second aspects of the present invention, when a part of teeth is worn due to meshing with another gear, the gear is rotated by a predetermined angle to fit the shaft fitting portion and the gear. By changing the fitting position with the mating part, the teeth meshing with other gears change. That is, new teeth that are not worn mesh with other gears. In this way, by sequentially rotating the gears by a predetermined angle and changing the teeth meshing with the other gears, all the teeth can be used effectively. As a result, it is possible to reduce the cost of replacement by reducing the number of replacement (replacement) of gears, and it is possible to respond quickly even when there is no stock of replacement gears.

It is a top view which shows the worm wheel which concerns on Embodiment 1 of this invention, and its peripheral member. It is a top view which shows the attachment state to the damper shaft of the worm wheel of FIG. It is a front view which shows the worm wheel of FIG. 1, and its peripheral member. It is a top view which shows the state which changed the attachment position of the worm wheel of FIG. It is a top view which shows the attachment state to the damper shaft of the worm wheel which concerns on Embodiment 2 of this invention. It is the top view (a) and front view (b) which show the attachment state to the damper shaft of the worm wheel which concerns on Embodiment 3 of this invention. It is a top view which shows the case where this invention is applied to a spur gear.

  The present invention will be described below based on the illustrated embodiments.

(Embodiment 1)
FIG. 1 is a plan view showing a worm wheel (a gear with which only some teeth mesh) 1 according to this embodiment and its peripheral members. The worm wheel 1 is paired with a worm (other gear) 2A to form a worm gear, and drives an outlet damper of an electric dust collector used in a power plant. Here, the worm wheel 1 includes a damper shaft 3 and a key 4 which will be described later.

  As shown in FIGS. 2 and 3, the worm wheel 1 is a flat helical gear, and a plurality of teeth 1 </ b> A are continuously formed on the outer periphery over the entire periphery. A circular shaft insertion hole 1a for inserting the damper shaft (shaft) 3 is formed concentrically with the center thereof, and a first key groove (covered) extending in the thickness direction is formed on the inner peripheral wall forming the shaft insertion hole 1a. (Fitting part) 1b is formed. The shape of the first key groove 1b is set so that the key (fitting part) 4 can be inserted and press-fitted (fitted) into the space formed by the second key groove 3a described later. ing.

  The damper shaft 3 has a cylindrical shape, and a total of four second key grooves 3a extending in the axial direction are formed on the outer periphery of the damper shaft 3 every 90 degrees about the axis. That is, in this embodiment, as will be described later, 1/4 of the entire teeth 1A of the worm wheel 1 (a region of 90 degrees from the center) meshes with the worm 2A, so the worm wheel 1 is rotated and fixed every 90 degrees. Four second keyways 3a are formed every 90 degrees so that the (attachment position can be changed). The damper shaft 3 is inserted into the shaft insertion hole 1a with the key 4 being inserted into the first key 1b groove and the second key groove 3a, so that the worm wheel 1 is connected to the upper end of the damper shaft 3. Is attached to the side. In addition, two damper blades 5 are arranged radially on the damper shaft 3, and the damper blade 5 is opened and closed by rotating the damper shaft 3.

  The worm 2A is a screw gear that meshes with the worm wheel 1 and is formed on the worm shaft 2. The worm shaft 2 is disposed so that the worm 2A meshes with the worm wheel 1 and is rotatably supported by the bearing 6. . Here, the hardness and wear resistance of the worm 2 </ b> A are set higher than those of the worm wheel 1. The worm shaft 2 is connected to a motor (not shown) so that it can rotate forward or backward as the motor rotates. Then, when the worm shaft 2 rotates in the forward direction (for example, rotates in the T1 direction in FIG. 1), the worm wheel 1 rotates in the T2 direction in FIG. The blade 5 opens. Similarly, when the worm shaft 2 is reversely rotated (for example, rotated in the direction T3 in FIG. 1), the worm wheel 1 is rotated in the direction T4 in FIG. The blade 5 is closed.

  Further, a flat bar-shaped limit plate 7 is attached to the upper end of the damper shaft 3 so that both ends thereof extend from the damper shaft 3. Further, when two limit switches 8A and 8B are arranged on a frame (not shown) and the end of the limit plate 7 hits the limit switches 8A and 8B as the worm wheel 1 (damper shaft 3) rotates, the motor Stops and the rotation of the worm wheel 1 (worm shaft 2) stops. In this embodiment, limit switches 8A and 8B are arranged so that the worm wheel 1 rotates (forward / reverse) by 90 degrees. That is, the worm wheel 1 rotates 90 degrees in the T2 direction from the state where one end of the limit plate 7 is in contact with the first limit switch 8A as shown in FIG. 1, and the other end of the limit plate 7 is the second end. When the limit switch 8B is hit, the rotation of the worm wheel 1 stops. Further, the limit switch 8A is set so that the rotation of the worm wheel 1 stops when the worm wheel 1 rotates 90 degrees in the T4 direction from that state and one end of the limit plate 7 hits the first limit switch 8A. , 8B are disposed.

  Thus, the worm wheel 1 rotates forward and backward by 90 degrees, and only the tooth 1A corresponding to the 90 degrees meshes with the worm 2A. That is, of the teeth 1A formed over the entire length of the outer periphery, only a part of the tooth group 1A1 as shown in FIG. 2 corresponding to ¼ of the whole meshes with the worm 2A. Then, the worm wheel 1 is removed from the damper shaft 3 and, for example, the worm wheel 1 is rotated (moved) by 90 degrees in the direction T5 in FIG. 2, and as shown in FIG. 4, the second key that faces the first key groove 1b. The worm wheel 1 is attached to the damper shaft 3 by inserting the key 4 into the key groove 3a. That is, the fitting position between the key grooves 1b and 3a and the key 4 is changed (the worm wheel 1 is rotated with respect to the axis of the damper shaft 3). Thus, the tooth 1A meshing with the worm 2A is changed to another tooth group 1A2.

  Next, the operation of the worm wheel 1 having such a configuration and the mounting method thereof will be described.

  First, as shown in FIGS. 1 and 2, in a state where the tooth group 1A1 of the worm wheel 1 is engaged with the worm 2A, the worm shaft 2 is rotated when the motor is rotated, and the worm wheel 1 and the damper shaft 3 are rotated along with this rotation. By rotating, the damper blade 5 opens and closes. At this time, the worm wheel 1 meshes with the worm 2A only in the tooth group 1A1, and by repeating the meshing, the tooth 1A of the tooth group 1A1 is worn, deteriorated (damaged), or the like. When wear or the like progresses, the worm wheel 1 is rotated 90 degrees around the axis as described above and reattached to the damper shaft 3, and the teeth 1A meshing with the worm 2A are changed to another tooth group 1A2. In this way, each time the wear of the teeth 1A progresses, the teeth 1A meshing with the worm 2A are sequentially changed to the tooth groups 1A3 and 1A4.

  As described above, according to the worm wheel 1 and its mounting method, when the tooth 1A meshing with the worm 2A is worn, the worm wheel 1 is worn by rotating it 90 degrees and reattaching it to the damper shaft 3. The new tooth 1A that has not been engaged meshes with the worm 2A. In this way, all the teeth 1A can be used effectively, the number of replacements of the worm wheel 1 can be reduced (1/4 of the conventional one), the replacement cost can be reduced, and the replacement worm wheel 1 can be reduced. It is possible to respond quickly even when there is no stock. Further, it is only necessary to form a plurality of second key grooves 3a on the outer periphery of the damper shaft 3, and the existing worm wheel 1 in which only one first key groove 1b is formed is used as it is. All the teeth 1A can be used effectively.

(Embodiment 2)
FIG. 5 is a plan view showing an attachment state of the worm wheel 10 according to this embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The worm wheel 10 is formed with a total of four first key grooves 1b every 90 degrees around the axis, and the damper shaft 3 is formed with one second key groove 3a. When changing the tooth 1A meshing with the worm 2A, the worm wheel 10 is removed from the damper shaft 3 and rotated 90 degrees to change the first key groove 1b opposed to the second key groove 3a, thereby changing the first key groove 1a. The key 4 is inserted into the key groove 1b and the second key groove 3a.

  Thus, according to this embodiment, all the teeth 1A can be effectively utilized by merely forming a plurality of first key grooves 1b in the worm wheel 10. Even if it is difficult to form a plurality of second key grooves 3a on the damper shaft 3 in terms of strength and the like, it is possible to effectively use all the teeth 1A. Furthermore, the existing worm wheel can be made effective by adding the first key groove 1b to the existing worm wheel 10 with respect to the existing worm wheel in which only one first key groove 1b is formed. It is possible to make effective use.

(Embodiment 3)
FIGS. 6A and 6B are a plan view and a front view showing a mounting state of the worm wheel 20 according to this embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In this embodiment, the upper end portion (fitting portion) 3A of the damper shaft 3 is formed in a quadrangular prism shape, and a rectangular shaft insertion hole (fitted portion) 20a for inserting (fitting) the upper end portion 3A is formed. The worm wheel 20 is formed. When changing the tooth 1A meshing with the worm 2A, the worm wheel 20 is removed from the damper shaft 3 and rotated 90 degrees (the fitting position between the upper end 3A and the shaft insertion hole 20a is shifted by 90 degrees), and the upper end 3A is inserted into the shaft insertion hole 20a.

  According to this embodiment, since the force / torque is transmitted from the worm wheel 20 to the damper shaft 3 by the square columnar upper end portion 3A, the local stress and impact force are reduced and the damper shaft is reduced as compared with the case of using the key. 3 and the deterioration and damage of the worm wheel 20 can be reduced. Further, in order to change the meshing tooth 1A, the worm wheel 20 can be removed from the damper shaft 3 and rotated 90 degrees, and the upper end 3A can be inserted into the shaft insertion hole 20a. Thus, the work can be performed easily and quickly.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the above-described embodiment, the case where the gear that meshes with only a part of the teeth is the worm wheel and the other gear is the worm, but other gears may be used. For example, as shown in FIG. 7, the gear with which only a part of the teeth mesh is a large diameter spur gear 30, the other gear is a small diameter spur gear 31, and the small diameter spur gear 31 is driven to rotate. The large-diameter spur gear 30 may be driven and rotated. In this case, for example, by providing two key grooves 30a in the large-diameter spur gear 30, the teeth 30A meshing with the small-diameter spur gear 31 can be changed.

  In the above embodiment, the fitting part (key or the like) has a convex shape and the fitting part (key groove or the like) has a concave shape, but the fitting part has a concave shape and is fitted. The part may be convex. Further, the fitting portion is not limited to the key 4 or the upper end portion 3A, but is a pin, for example, and a plurality of pin holes into which the pins are inserted are provided in the worm wheel 1 or the damper shaft 3, and the pin holes to be inserted are changed. The teeth 1A meshing with the worm 2A may be changed. In the above-described embodiment, the worm wheel can be rotated every 90 degrees to change the mounting position. However, depending on the tooth area (the size of the tooth group) that meshes with other gears. For example, it is possible to change the angle every 120 degrees or 180 degrees.

1, 10, 20 Worm wheel (gear that only some teeth mesh)
1A tooth 1A1 to 1A4 tooth group 1a shaft insertion hole 1b first keyway (fitting part)
2 Worm shaft 2A Worm (other gear)
3 Damper shaft (shaft)
3a Second keyway 3A Upper end (fitting part)
4 Key (Fitting part)
20a Shaft insertion hole (fitting part)

Claims (2)

Teeth are continuously formed in the circumferential direction, and by rotating by a predetermined angle, only some of the teeth mesh with other gears, and only some of the teeth mesh with each other,
The gear having a shaft insertion hole and a first keyway formed in an inner peripheral wall of the shaft insertion hole;
A shaft provided with a plurality of second key grooves on the outer periphery;
A key insertable into the first keyway and the second keyway;
With
The second key groove is formed at every predetermined angle so that the gear can be rotated and fixed every predetermined angle, and the first key groove into which the key is inserted by rotating the gear around an axis. And by changing the fitting position of the second keyway, the teeth meshing with the other gear are changed.
A gear that meshes with only a part of teeth. A method of attaching a gear in which teeth are continuously formed in the circumferential direction, and only a part of the teeth meshes with another gear by rotating by a predetermined angle, and only a part of the teeth meshes.
The gear is provided with a shaft insertion hole and a first key groove formed on the inner peripheral wall of the shaft insertion hole,
Providing a plurality of second key grooves on the outer periphery of the shaft;
A second key groove is formed at each predetermined angle so that the gear can be rotated and fixed every predetermined angle, and the first key groove into which the key is inserted by rotating the gear around an axis. By changing the fitting position with the second key groove, the teeth meshing with the other gear are changed.
A gear mounting method in which only some of the teeth mesh with each other.

Images