JP2001132822A - Gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear device capable of improving the durability without abrading and damaging gears by interference, rubbing and the like with a spring as well as to provide a gear device eliminating uselessness in part specifications and being relatively easy in meshing work with a mating gear. SOLUTION: In this gear device 1 having plural gears 2, 4 combined so as to be relatively displaceable in the circumferential direction, the gear device 1 has one gear 4 for setting at least one of an outer diameter, a pitch circle diameter and a tooth bottom circle diameter larger than the other gear 2, setting a module equal to the other gear 2 and having the tooth number set so as to be different from the other gear 2 and an elastic body 3 for relatively displaceably supporting this one gear 4 in the circumferential direction and the radial direction to the other gear 2, and at least one of the one gear 4 and the elastic body 3, and the elastic body 3 and the other gear 2 is made slidable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear train which is a kind of a transmission, and more particularly to an improvement of a gear train having a function of reducing or eliminating backlash.

[0002]

2. Description of the Related Art Conventionally, a gear device 51 shown in FIGS. 5 and 6 has been known, and is configured as follows.

[0003] First, a first gear 52 integrally formed with a boss 52a is provided on the inner periphery, and a second gear 53 is provided with teeth 52 on the outer periphery of the boss 52a of the first gear 52.
b and 53a are combined so as to be relatively displaceable in the circumferential direction with the phases shifted from each other.
The disc spring 54 presses the second gear 53 against the first gear 52 so that the disc spring 54 does not come off, and the boss of the first gear 52 also prevents the disc spring 54 from coming off the first gear 52. Bush 5 press-fitted on the inner peripheral side of portion 52a
5 supports the disc spring 54 at its flange portion 55a, or a C-shaped retaining ring groove is provided on the outer peripheral side of the boss portion 52a, and the C-shaped retaining ring supports the disc spring 54 (not shown). . The first gear 52 and the second gear 53 have the same outer diameter, pitch circle diameter, and root circle diameter, the same module, and the same number of teeth.

[0004] Further, between the two gears 52, 53, mounting grooves 56, which are elastic body mounting spaces, are provided in a required number of evenly arranged so as to be surrounded by the gears 52, 53 (four in the figure). In each of the mounting grooves 56, a metal spring 57 having a coil shape is mounted in the mounting groove 56 in the circumferential direction of each of the gears 52 and 53.

[0005] The gear device 51 having the above-described structure, when a mating gear (not shown) meshes with the first and second gears 52 and 53, the teeth 52b and 5 of the two gears 52 and 53.
3a is configured to reduce or eliminate the backlash by sandwiching the teeth of the mating gear by the elasticity of the spring 57, but has the following disadvantages.

That is, firstly, the elastic means for elastically returning the first and second gears 52 and 53 in the circumferential direction so as to sandwich the teeth of the mating gear is constituted by a metal spring 57 having a coil shape. Since 57 is mounted in the mounting groove 56 of the gears 52 and 53, the interference portion 56a and the seat portion 56b with the spring 57 in the mounting groove 56 may be worn due to contact with the rigid material, and thus the interference portion 56a When the seat 56b wears, the spring characteristics of the spring 57 will change. In addition, the spring 57 rattles in the mounting groove 56, and during the progress of wear, the spring 57 and the seat portion 56b may rub against each other, generating a loud noise.

When the elastic means is constituted by a coiled metal spring 57 as described above, the mounting groove 5 is formed by an elastic load acting in the circumferential direction.
6. Stress concentration is likely to occur at the inner wall corner 56c of the gear 6, and when such stress concentration occurs, the gear 5
2,53 may be damaged.

The gear device 51 includes a disc spring 54 and a bush 55 which do not directly contribute to the transmission of the rotational torque.
Since such accessory parts are provided, it is inevitable that the parts specifications are wasteful, and it takes much time and effort to manufacture and assemble them, and is disadvantageous in terms of cost.

The number of teeth of the first and second gears 52, 53 is set equal to each other, and both gears 52, 53
The phases of the teeth 52b and 53a are shifted over the entire circumference, so that when the two gears 52 and 53 are engaged with the mating gear, the two gears 52 and 53 are opposed to each other against the elasticity of the spring 57. It has to be displaced, so that the work of meshing or combining with the mating gear is somewhat cumbersome.

[0010]

SUMMARY OF THE INVENTION In view of the above, the present invention makes it possible to improve the durability of a gear without being worn or broken due to interference or friction with a spring. It is another object of the present invention to provide a gear device that can provide a simple gear device, and in addition to this, has no waste in component specifications and is relatively easy to engage with a mating gear.

[0011]

In order to achieve the above object, a gear device according to the present invention is a gear device having a plurality of gears combined so as to be relatively displaceable in a circumferential direction.
At least one of the pitch circle diameter and the root circle diameter is set larger than the other gears, the module is set equal to the other gears, and the number of teeth is set differently from the other gears. An elastic body that supports the one gear so as to be relatively displaceable in a circumferential direction and a radial direction with respect to another gear, and at least one of the one gear and the elastic body and the elastic body and the other gear It is characterized in that one can be slid.

In the gear device of the present invention having the above-described configuration, when a plurality of gears are meshed with a mating gear, at least one of the outer diameter, the pitch circle diameter, and the root circle diameter of one gear is changed to the other. The gear is set larger than the gear, the module is set equal to the other gear, the number of teeth is set different from the other gear, and this one gear is elastically displaced relative to the other gear in the radial direction. The gear is pushed by the mating gear to be displaced in the radial direction relative to the other gear, and is pressed against the mating member by the repulsive force of the elastic body. Based on the number difference, it is displaced in the circumferential direction with respect to the other gears,
At least one of the one gear and the elastic body and the elastic body and the other gear slide, and the backlash in the circumferential direction of the backlash can be reduced by the sliding resistance.

Further, based on the difference in the number of teeth between one gear and the other gear, the phase of the teeth of the one gear and the other gear coincides with each other in a part of the circumferential direction. If you make it mesh with the mating gear in the part,
The meshing operation can be performed without relative displacement of the plurality of gears in the circumferential direction.

In the present invention, the number of gears arranged in parallel is plural, including two gears, and three or more gears. The gear device includes various gears such as spur teeth, helical teeth, and worm wheels. The elastic body includes both a rubber-like elastic body and a spring.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a gear device 1 according to an embodiment of the present invention.
Is shown in FIG. 2, and its operation state is shown in FIG.

The gear device 1 according to the embodiment is used as a spur gear in various torque transmitting portions.
It is configured as follows.

First, a first gear 2 provided with a cylindrical boss 2b on the inner periphery is provided as a driving force transmitting gear, and the first gear 2 has an annular shape on the outer periphery of the boss 2b. An elastic body 3 made of a rubber-like elastic body is arranged concentrically, and a second gear 4 is arranged concentrically on the outer peripheral side of the elastic body 3 as a gear for reducing backlash. The boss portion 2b is formed integrally with the main body of the first gear 2, but may be formed separately and fixed to each other. The elastic body 3 is fitted to the outer periphery of the boss 2b with a predetermined interference, and the second gear 4 is also fitted to the outer periphery of the elastic body 3 with a predetermined interference.

The outer diameter of the second gear 4 is set to be larger than the outer diameter of the first gear 2 so that the second gear 4 comes into contact with the other gear prior to the first gear 2 in the meshing operation with the other gear. Have been. Further, the module of the teeth 4a of the second gear 4 is set to be equal to the module of the teeth 2a of the first gear 2, and the number of the teeth 4a is set to be more required than the number of the teeth 2a of the first gear 2. ing. The second gear 4 is supported by the elastic body 3 so as to be relatively displaceable in the circumferential direction and the radial direction with respect to the first gear 2. The second gear 4 and the elastic body 3, and the elastic body 3 and the first One or both of the gears 2 are slidable in the circumferential direction at the contact portions 5 and 6.

When the first and second gears 2 and 4 of the gear device 1 having the above configuration are engaged with the mating gear 12 as shown in FIG. 2, the outer diameter of the second gear 4 is increased as described above. The size is set larger than the outer diameter of the first gear 2, the module is set equal to the first gear 2, the number of teeth is set as many as required than the first gear 2, and the second gear 4 is elastic. Since the second gear 4 is supported by the body 3 so as to be relatively displaceable in the radial direction with respect to the first gear 2, the second gear 4 is pushed downward in the drawing by the mating gear 12, and , And is pressed toward the mating gear 12 by the repulsive force of the elastic body 3. In this state, when the transmission torque is input and the gears 2, 4, and 12 rotate,
Based on the difference in the number of teeth between the first gear 2 and the second gear 4, the second gear 4 is relatively displaced in the circumferential direction with respect to the first gear 2, and the second gear 4, the elastic body 3, and the elastic body 3 At least one of the first gears 4 slides at the contact portions 5,6.
Therefore, the backlash between the gear device 1 and the mating gear 12 in the circumferential direction can be reduced by the sliding resistance generated at this time, and the rattling noise can be reduced. As described above, FIG. 2 shows a state in which the second gear 4 is pushed down by the mating gear 12 and is displaced relative to the first gear 2 downward in the drawing. 2, 4, and 12 will start rotating.

In the gear device 1 having the above structure,
Based on the difference in the number of teeth of the first and second gears 2 and 4, the phases of the teeth 2a and 4a of the two gears 2 and 4 coincide in a part of the circumferential direction. By meshing with the mating gear 12, the meshing operation can be performed without relatively displacing the gears 2 and 4 in the circumferential direction. Therefore, the operation of meshing with the mating gear 12 can be facilitated.

Further, the elastic means for connecting the first and second gears 2 and 4 so as to be relatively displaceable is not a coil-shaped metal spring mounted in the mounting groove of the gears as in the prior art, but is a combination of the two gears 2 and 4. Since the elastic member 3 is formed of an annular rubber-like elastic member interposed therebetween, the elastic member 3
Due to the relatively soft material characteristics, the gears 2 and 4 made of metal or resin can be prevented from being worn out or damaged, or generating a loud noise. Therefore, the durability of each of the gears 2 and 4 can be improved, and the occurrence of abnormal noise can be suppressed and the gear device 1 excellent in quietness can be provided.

Since the elastic member 3 and the second gear 4 are simply added to the first gear 2 having the boss portion 2b as described above, the coned disk spring of the prior art is used. It is possible to eliminate the necessity of any additional parts such as the bush and the bush. Therefore, it is possible to provide the gear device 1 which is easy to manufacture and assemble, has no waste in component specifications, and is advantageous in cost.

Second Embodiment FIG. 3 shows a half cross section of a gear device 1 according to a second embodiment of the present invention. This gear device 1 is used as a helical gear for various torque transmitting portions. And is configured as follows.

First, a first gear 2 is provided as a first driving force transmitting gear, and a cylindrical boss 8 is fixed to the inner peripheral side of the first gear 2 by means such as fitting or press fitting. ing. Although the first gear 2 and the boss 8 are formed separately from each other, they may be formed integrally.

A third gear 9 as a second driving force transmitting gear is fixed to the outer peripheral side of the boss portion 8 along with the first gear 2 by means such as fitting or press fitting.
9, the second gear 4 as a gear for reducing backlash
Is provided.

An annular connecting member 10 is fixed between the first and third gears 2 and 9 on the outer peripheral side of the boss portion 8 by means such as fitting or press fitting. An elastic body 3 made of an annular rubber-like elastic body is concentrically arranged on the outer peripheral side, and the second gear 4 is concentrically arranged on the outer peripheral side of the elastic body 3. The elastic body 3 is fitted to the outer periphery of the boss 8 with a predetermined interference, and the second gear 4 is also fitted to the outer periphery of the elastic body 3 with a predetermined interference.

The second gear 4 has an outer diameter dimension of the first and third gears 2 so that the second gear 4 comes into contact with the first and third gears 2 and 9 earlier than the first and third gears 2 and 9 in the meshing operation with the other gear. , 9 are set larger than the outer diameter dimension. The module of the teeth 4a of the second gear 4 is set to be equal to the module of the teeth 2a and 9a of the first and third gears 2 and 9, and the number of the teeth 4a is the same as that of the first and third gears 2 and 9. The required number is set to be larger than the number of the nine teeth 2a and 9a. The second gear 4 is supported by the elastic body 3 so as to be relatively displaceable in the circumferential direction and the radial direction with respect to the first and third gears 2 and 9.
Either one or both of the elastic member 3 and the connecting member 10 on the first and third gears 2 and 9 side are slidable in the circumferential direction at the contact portions thereof.

When the first to third gears 2, 4, and 9 of the gear device 1 having the above-described configuration are meshed with the mating gear, the outer diameter of the second gear 4 becomes first and second as described above. The outer diameter of the three gears 2, 9 is set larger than the first and third gears 2, 9;
The number of teeth is set to be larger than that of the first and third gears 2 and 9, and the second gear 4 can be radially displaced relative to the first and third gears 2 and 9 by the elastic body 3. Because of being supported, the second gear 4 is pushed by the mating gear and relatively displaced in the radial direction with respect to the first and third gears 2 and 9, and is pressed against the mating gear by the repulsive force of the elastic body 3. . Then, in this state, when the transmission torque is input and each of the gears 2, 4, and 9 rotates, the second gear 4 is rotated based on the difference in the number of teeth between the first and third gears 2 and 9 and the second gear 4. It is relatively displaced in the circumferential direction with respect to the first and third gears 2 and 9, and at least one of the second gear 4 and the elastic body 3 and the elastic body 3 and the connecting member 10 on the first and third gears 2 and 9 side One slides at the contact. Therefore, the play in the circumferential direction due to the backlash between the gear device 1 and the mating gear can be reduced by the sliding resistance generated at this time, and the magnitude of the rattling noise can be reduced.

In the gear device 1 having the above structure,
On the basis of the difference in the number of teeth between the first and third gears 2, 9 and the second gear 4, there are places where the phases of the teeth 2a, 4a, 9a of the gears 2, 4, 9 coincide in part in the circumferential direction. Therefore, by meshing with the mating gear at this phase matching portion, the meshing operation can be performed without relatively displacing the gears 2, 4, and 9 in the circumferential direction. Therefore, the operation of meshing with the mating gear can be facilitated.

Further, the elastic means for connecting the first and third gears 2, 9 and the second gear 4 so as to be relatively displaceable is not a coil-shaped metal spring mounted in a mounting groove as in the prior art, but a second spring. Since the elastic member 3 is formed of an annular rubber-like elastic member interposed between the gear 4 and the connecting member 10 on the first and third gears 2 and 9 side, the elastic member 3 is relatively soft. Depending on the material properties, it is possible to prevent the gears 2, 4, and 9 made of metal or resin from being worn or damaged, and from generating a loud noise. Therefore, the durability of each of the gears 2, 4, and 9 can be improved, and the occurrence of abnormal noise can be suppressed to provide the gear device 1 that is excellent in quietness.

Further, as described above, the first gear 2 having the boss portion 8 is configured to have only the third gear 9, the connecting member 10, the elastic body 3 and the second gear 4 added thereto. Therefore, it is not necessary to use any additional parts such as the coned disc spring and the bush in the above-mentioned prior art. Therefore,
It is possible to provide the gear device 1 which is easy to manufacture and assemble, has no cost in component specifications, and is cost effective.

A second gear 4 which can be displaced relative to the first and third gears 2, 9 is arranged between the first and third gears 2, 9 and at the center in the axial direction. For this reason, the transmission torque is limited to each tooth 2 of the first and third gears 2 and 9.
a, 9a are transmitted uniformly to the tooth surfaces. Therefore, occurrence of uneven wear on the tooth surfaces 2a and 9a can be suppressed, and the rattling noise can also be reduced.

Furthermore, if a space 11 is formed between the first gear 2 and the second gear 4 and between the second gear 4 and the third gear 9 by an axial gap, oil accumulates in the space 11. This can increase the lubrication effect. Therefore, the occurrence of wear on the tooth surfaces of the teeth 2a, 4a, 9a can be further suppressed.

The gear device 1 according to the second embodiment is
As shown in FIG. 4, a worm wheel or the like can be used.

[0036]

The present invention has the following effects.

That is, first, in the gear device of the present invention having the above-described configuration, when a plurality of gears are meshed with a mating gear, the outer diameter, the pitch circle diameter, and the root bottom circle diameter of one of the gears are determined. At least one is set larger than the other gears, the module is set equal to the other gears, the number of teeth is set to be different from the other gears, and this one gear is elastically set with respect to the other gears. Because it is supported so that it can be relatively displaced in the radial direction, this one gear is pushed by the mating gear and relatively displaced in the radial direction with respect to the other gear, and is pressed against the mating member by the repulsive force of the elastic body,
In this state, when the transmission torque is input and each gear rotates, one gear is displaced relative to the other gear in the circumferential direction based on the difference in the number of teeth, and one gear and the elastic body and the elastic body are displaced. And at least one of the other gears slides at the contact portion. Therefore, the backlash between the gear device and the mating gear in the circumferential direction can be reduced by the sliding resistance generated at this time, and the rattling noise can be reduced.

In the gear device of the present invention having the above configuration, the phases of the teeth of the two gears coincide with each other in a part of the circumferential direction based on the difference in the number of teeth between the one gear and the other gear. Therefore, by meshing with the mating gear at this phase matching portion, the meshing operation can be performed without relatively displacing the two gears in the circumferential direction. Therefore, the operation of meshing with the mating gear can be facilitated.

Further, the elastic means for connecting one gear and the other gear so as to be relatively displaceable is not a coil-shaped metal spring mounted in the mounting groove of the gear as in the prior art, but is interposed between the two gears. Due to the relatively soft material characteristics of the elastic body and the arrangement that is not mounted in the mounting groove, each metal or resin gear may be worn or broken, Generation of sound can be prevented. Therefore, the durability of each gear can be improved, and the occurrence of abnormal noise can be suppressed, and a gear device excellent in quietness can be provided.

Further, since the gear device which does not require the accessory parts such as the disc spring and the bush in the above-mentioned prior art is constituted, there is no waste in the specification of parts, and the manufacture and assembly are easy.
It is possible to provide a gear device that is advantageous in cost.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a gear device according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing an operation state of the gear device.

FIG. 3 is a half sectional view of a gear device according to a second embodiment of the present invention.

FIG. 4 is a half sectional view of a gear device according to another embodiment of the present invention.

FIG. 5 is a partially cutaway front view of a gear device according to a conventional example, and the right half is a cross-sectional view taken along line BB in FIG.

FIG. 6 is a sectional view taken along line AOA in FIG. 5;

[Explanation of symbols]

 Reference Signs List 1 gear device 2 first gear (other gear) 2a, 4a, 9a tooth 2b, 8 boss portion 3 elastic body 4 second gear (one gear) 5, 6 contact portion 7 phase matching portion 9 third gear (other) 10) Coupling member 11 Space 12 Mating gear

Claims (1)

[Claims] 1. A gear device (1) comprising a plurality of gears (2) and (4) combined so as to be relatively displaceable in a circumferential direction, wherein at least one of an outer diameter, a pitch circle diameter, and a root circle diameter is provided. One gear (4) with one set larger than the other gear (2), the module set equal to the other gear (2), and the number of teeth set different from the other gear (2) An elastic body (3) that supports the one gear (4) so as to be relatively displaceable in a circumferential direction and a radial direction with respect to another gear (2); and the one gear (4) and the elastic body. (3) A gear device wherein at least one of the elastic body (3) and another gear (2) is slidable.