JP2015059586A - Trapezoidal tooth trace gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear that enables heavy-load power transmission by smoothing an engaged state of teeth to prevent generation of noises and vibrations.SOLUTION: A trapezoidal tooth trace gear includes a tooth 2 with a trapezoidal tooth trace, which comprises a linear tooth part 4 formed in a central position in a tooth width direction, and a pair of helical tooth parts 5 and 6 twisted in directions opposite to each other and formed in both end positions in the tooth width direction. Particularly, the linear tooth part 4 is formed in such a shape that its tooth-width-direction length L1 is greater than a pitch of teeth 3 and smaller than the tooth-width-direction length L2 of the helical tooth parts 5 and 6.

Description

  The present invention relates to a technique of a trapezoidal helical gear, and more particularly, to a technique of a trapezoidal helical gear having teeth formed in a trapezoidal shape.

  Conventionally, as a gear constituting a power transmission mechanism (gear device) of an automobile part, a precision machine, an office machine, an electronic device, etc., generally, a straight tooth is formed so that a tooth line is parallel to an axis. Combines a set spur gear, a helical gear that is twisted in the circumferential direction so that the tooth line is at a constant angle (twisting direction), or a pair of helical gears with opposite twisting directions. Spiral gears having a shape like that are used.

  In helical gears, the meshing state of a tooth is maintained until the next tooth is sufficiently meshed, so that fluctuations in transmission torque and meshing force between gears during power transmission are suppressed, resulting in noise compared to a spur gear. And vibration are reduced, and high load power transmission becomes possible. However, on the other hand, since the tooth trace is twisted with respect to the shaft, a thrust force is generated in the axial direction, and a bearing structure for receiving a thrust load is required. In that respect, the helical gear cancels the axial thrust force and does not generate a thrust load, thus eliminating the above-described drawbacks of the helical gear.

  In this way, the helical gear eliminates the disadvantages of the spur gear and the helical gear, but structurally, it has a V-shaped top that is formed at the center position in the tooth width direction when the teeth are engaged. Since the stress is concentrated, there is a problem in that a tooth root stress larger than that at other portions acts on the top portion and the life is reached quickly. Further, if the gear accuracy (machining accuracy) is insufficient, a meshing failure is likely to occur at the top, causing noise and vibration.

  From such a viewpoint, as disclosed in, for example, Patent Document 1 or Patent Document 2, the conventional angle gear configuration is configured such that the pressure angle and the dislocation coefficient at the center position in the tooth width direction are larger than those at other locations. The formed configuration is proposed, and as disclosed in Patent Document 3, the crest side tooth surface and the trough side tooth surface of the standard tooth from the crest side tooth surface and the trough side tooth surface from both end positions in the tooth width direction. The structure etc. which were formed so that it might leave | separate inside, so that it approached the center position of a tooth width direction are proposed.

JP 2008-101700 A JP 2008-144924 A JP 2008-232383 A

  Certainly, according to the configuration of the conventional spur gear disclosed in Patent Document 1 to Patent Document 3 described above, the width of the tooth is formed by forming the specifications of the center position in the tooth width direction differently from other parts. Improvement of tooth root strength at the center in the direction and prevention of poor meshing at the top can be expected. However, in the configuration of such a spur gear, since the specifications are gradually changed at the center position in the tooth width direction and other places, in order to keep the teeth meshing smoothly along the tooth line, There is a problem in that it is necessary to set specifications for advanced gears, and the expected effect cannot be realized depending on the gear accuracy (machining accuracy).

  In view of this, the present invention relates to a trapezoidal toothed gear that solves the above-mentioned conventional problems, and a gear capable of smoothing the meshing state of the teeth to prevent noise and vibration and capable of transmitting high-load power. The purpose is to provide.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, a straight tooth portion formed at the center position in the tooth width direction and a pair of helical tooth portions opposite in the twist direction formed at both end positions in the tooth width direction, The tooth streaks have trapezoidal teeth.

  According to a second aspect of the present invention, the linear tooth portion is formed so that a tooth width direction length is larger than a tooth pitch and smaller than a tooth width direction length of the helical tooth portion. is there.

  According to a third aspect of the present invention, the helical tooth portion is formed such that the axis perpendicular to the axis has the same shape in the tooth width direction.

  According to a fourth aspect of the present invention, the linear tooth portion is continuous with the helical tooth portion at both ends in the tooth width direction.

  According to a fifth aspect of the present invention, a meshing escape portion cut out from the tooth tip surface to the vicinity of the tooth bottom surface along the tooth width direction of the concave tooth surface of the linear tooth portion is formed.

  According to a sixth aspect of the present invention, a meshing relief portion cut out from the tooth tip surface to the vicinity of the tooth bottom surface is formed on the concave tooth surface of the continuous portion of the linear tooth portion and the helical tooth portion. .

  As an effect of the present invention, the meshing state of the teeth is smooth, the generation of noise and vibration can be prevented, and high load power transmission is possible.

It is the perspective view which showed the whole structure of the gearwheel which concerns on one Example of this invention. FIG. 2 is an axial perspective view of the gear of FIG. 1. It is the front view which showed the tooth trace of the gearwheel typically. It is the top view which expanded and showed the tooth | gear of the gearwheel. It is the AA arrow sectional drawing in FIG. 3 which showed the axial orthogonal cross-section tooth profile of the helical tooth part. It is the top view which expanded and showed the tooth | gear of the gear of another Example. It is the top view which expanded and showed the tooth | gear of the gear of another Example. It is the top view which expanded and showed the tooth | gear of the gear of another Example.

  Next, modes for carrying out the invention will be described.

  As shown in FIG. 1 to FIG. 3, the gear 1 of the present embodiment is a trapezoidal helical gear having a plurality of teeth 3,... Having a trapezoidal shape on the surface (circumferential surface) of the gear base 2. It is configured. In the gear 1 of this embodiment, the gear base 2 is formed in a cylindrical shape having a circular cross section, and a rotation shaft (not shown) is inserted into a shaft hole 2 a provided along the shaft core C, so that a pair of gears 1. 1 is meshed and rotated so that power can be transmitted between the rotating shafts. A plurality of teeth 3 (linear teeth 4 and helical teeth 5 and 6) are integrally formed on the gear base 2.

  As shown in FIGS. 3 and 4, the teeth 3 are formed in a trapezoidal shape as described above, and the linear tooth portion 4 formed at the center position in the tooth width direction and at both end positions in the tooth width direction. It is composed of a pair of helical teeth 5 and 6 having opposite twist directions. Note that the plan view of the tooth 3 shown in FIG. 4 schematically shows an enlarged view of one tooth 3 in the gear 1, and the one tooth 3 of the gear 1 is arranged on the pitch circle in the tooth width direction. This corresponds to the cross-sectional shape of the tooth 3 that appears when cut.

  Here, the “trapezoidal shape” of the present embodiment is a representation of the shape of the tooth 3 of the tooth 3, and the “straight shape” of the spur gear, the “mountain shape” of the spur gear. It is different from the tooth shape of “shape”. Specifically, the center position in the tooth width direction of the tooth 3 corresponds to the upper base of the trapezoid, and both end positions in the tooth width direction of the tooth 3 correspond to the trapezoidal leg (note that there is no equivalent to the lower base of the trapezoid). ). In this embodiment, the tooth 3 is formed so that the center position in the tooth width direction is a straight line parallel to the axis C, and the both end positions in the tooth width direction are obliquely spread (twisted) in a symmetric direction toward the tooth end. ing.

  The straight tooth portion 4 is formed so as to be parallel to the axis C at the center position in the tooth width direction of the tooth 3. The helical tooth portions 5 and 6 are formed so as to have a helical shape (helical shape) of a pair of helical gears formed in symmetrical shapes with opposite torsional directions at both ends in the tooth width direction. The linear teeth 4 are extended toward the opposite tooth ends with reference to the straight teeth 4. The helical tooth portion 5 is shaped so that the twisting direction rises to the right (right twist) at a position on the one end side in the tooth width direction (left side position in FIG. 3). On the other hand, the helical tooth portion 6 rises to the left (twisted left) in the twist direction to the position on the other end side in the tooth width direction opposite to the helical tooth portion 5 (right side position in FIG. 3). It is shaped like this.

  The tooth 3 has a straight tooth portion 4 and helical tooth portions 5 and 6 that are continuous at both ends of the straight tooth portion 4 in the tooth width direction. The tooth and the tooth surface of the helical tooth portions 5 and 6 are continuous, and the convex tooth surface 3a (the lower tooth surface in FIG. 4) of the tooth 3 is the straight tooth portion 4 and the helical tooth. The concave tooth surface 3b (upper tooth surface in FIG. 4) of the tooth 3 is bent through the continuous portions of the portions 5 and 6, and the straight tooth portion 4 and the helical tooth portions 5 and 6 are formed. It is bent and continued through the continuous part.

  The gear 1 according to the present embodiment has various gear specifications appropriately designed. Specifically, the gear specifications, the gear, the pressure angle, the tooth width, the number of teeth, the dislocation amount (dislocation coefficient), and the twist angle. (21.5 ° to 45 °), material, manufacturing method, and the like are selected according to applications and intended use.

  As shown in FIG. 4, the dimension design of the tooth 3 is that the straight tooth portion 4 has a tooth width direction length L1 larger than the pitch of the tooth 3 and the helical tooth portions 5 and 6. It is formed to be smaller than the tooth width direction length L2. The “pitch of the teeth 3” is the pitch of the reference molded teeth obtained by developing the gear 1 on a plane. The linear tooth portion 4 is preferably formed such that the tooth width direction length L1 is 3.5 times or more the module (pitch / π) of the gear 1. Further, the helical tooth portions 5 and 6 are preferably formed such that the tooth width direction length L2 is 1.2 times or more the tooth width direction length L1 of the linear tooth portion 4.

  As shown in FIG. 5, the tooth profile of the tooth 3 is formed so that the axially perpendicular section tooth profile S <b> 1 has the same shape in the tooth width direction in the helical tooth portions 5 and 6. In particular, in the gear 1 of the present embodiment, the straight tooth section S2 is formed so that the straight tooth section S2 has the same shape as the right tooth section S1 of the helical tooth sections 5 and 6 in the straight tooth section 4. The toothed portion 4 and the helical toothed portions 5 and 6 are continuous in the tooth width direction with the axially perpendicular section tooth shapes S1 and S2 having the same shape.

  The material of the gear 1 is not particularly limited, and normal materials such as copper materials and resins (plastics) are used in addition to various steel materials such as raw steel and stainless steel.

  The manufacturing method of the gear 1 is not particularly limited. When various steel materials are mainly used as a material, the gear 1 is manufactured by machining such as gear cutting or pressing called a forming method or a generating method, and as a material. When resin (plastic) is used, it is manufactured by resin processing such as injection molding. In particular, since the gear 1 of the present embodiment is formed so that the teeth of the teeth 3 have a trapezoidal shape, the above-described gear cutting and press working are difficult to machine, and the gear accuracy (processing accuracy) is poor. Preferably, it is manufactured by electrical discharge machining, 5-axis machining, or the like using a reference rack in which predetermined reference forming teeth are formed as a machining electrode. According to these electric discharge machining and the like, the gear accuracy (machining accuracy) of the gear 1 can be improved, and the axially perpendicular cross-section tooth profile S1 extends in the tooth width direction in the helical tooth portions 5 and 6 as described above. It is easy to form the same shape.

  As described above, the gear 1 according to the present embodiment includes the linear tooth portion 4 formed at the center position in the tooth width direction and the pair of halves opposite in the twist direction formed at both end positions in the tooth width direction. Since the tooth streaks composed of the toothed portions 5 and 6 have trapezoidal teeth 3 and 3, the meshing state of the teeth 3 is smooth and noise and vibration can be prevented, and high load power transmission can be achieved. It becomes possible.

  That is, in the gear 1 of the present embodiment, since the linear tooth portion 4 is formed at the center position in the tooth width direction, the tooth shape in the center position in the tooth width direction is changed as compared with the conventional spur gear. Therefore, it is possible to reduce the meshing failure caused by the gear accuracy (machining accuracy), prevent the generation of noise and vibration, and extend the life of the center position of the tooth 3 in the tooth width direction. In addition, a pair of helical teeth 5 and 6 having opposite torsional directions are formed at both end positions in the width direction of the tooth, so that the engagement state is long and the contact area can be increased, and high load power transmission is achieved. Is possible. By providing the linear tooth portion 4 and the helical tooth portions 5 and 6 in this way, the meshing of the teeth 3 is smooth, noise (including intermittent noise) and vibration can be prevented, and high load Power transmission is possible. Furthermore, it is not necessary to set advanced gear specifications such as gradually changing the specifications in the tooth width direction, making it easy to design and process the teeth 3 (straight tooth portions 4 and helical tooth portions 5 and 6). Thus, variations in the quality of the gear 1 can be suppressed.

  The gear 1 of the present embodiment cancels the axial thrust force and does not generate a thrust load, and the bearing structure is simplified and the entire apparatus can be downsized. For example, smooth driving is required. Products (industrial robots, pumps, etc.) and products that require silent drive (medical equipment, military equipment, in-vehicle acoustic equipment, etc.), automobile parts, precision machinery, office equipment, electronic equipment, etc. It can be used in power transmission mechanisms (gear devices) for high value-added products.

  In particular, in the gear 1 of the present embodiment, the tooth width direction length L1 is larger than the pitch of the teeth 3 at the straight tooth portion 4, and the tooth width direction length L2 of the helical tooth portions 5 and 6 is. Therefore, the meshing state of the teeth 3 can be made smoother and noise and vibration can be effectively prevented. That is, in the linear tooth portion 4, when the tooth width direction length L 1 is smaller than the pitch of the teeth 3, a large root stress acts on the linear tooth portion 4, and the life of the linear tooth portion 4 is reduced. Noise and vibration due to poor meshing are generated. On the other hand, if the length L2 of the helical tooth portions 5 and 6 is greater than the width L2, the noise and vibrations caused by the helical tooth portions 5 and 6 are generated. This is because the effect of reducing the above cannot be exhibited.

  Further, in the gear 1 of this embodiment, the helical tooth portions 5 and 6 are formed such that the axial perpendicular cross-sectional tooth profile S1 has the same shape in the tooth width direction. It is possible to increase the meshing accuracy of the portions 5 and 6 and make the meshing state of the teeth 3 smoother.

  In the gear 1 of this embodiment, since the linear tooth portion 4 is continuous with the helical tooth portions 5 and 6 at both ends in the tooth width direction, the tooth root strength of the tooth linear tooth portion 4 is increased. The life of the center position in the width direction of the tooth 3 can be extended.

  The configuration of the gear 1 is not limited to the above-described embodiment, and various modifications can be made without departing from the object of the present invention.

  That is, in the gear 1 of the above-described embodiment (see FIG. 4 and the like), the configuration in which the linear tooth portion 4 is continuous with the helical tooth portions 5 and 6 at both ends in the tooth width direction in the tooth 3 has been described. However, the shape of the tooth 3 is not limited to this, and the tooth 3 may be formed so as to have a trapezoidal shape as a whole. For example, like the tooth 103 of the embodiment shown in FIG. 6, separations 107 and 107 are provided at both ends in the tooth width direction of the linear tooth portion 104, and the linear tooth portion 104 and the helical tooth portion 105. 106 may be formed discontinuously. In such a case, the tooth width direction length L1 of the straight tooth portion 104 and the tooth width direction length L2 of the helical tooth portions 105 and 106 are the tooth widths between both tooth ends excluding the separation 107 and 107. Corresponds to the length of the direction.

  Further, in the gear 1 of the above-described embodiment (see FIG. 4 and the like), the configuration in which the axially perpendicular sectional tooth profile S2 is formed in the linear tooth portion 4 so as to have the same shape in the tooth width direction has been described. The shape of the linear tooth portion 4 is not limited to this, and, for example, the tooth tip along the tooth width direction of the concave tooth surface 203b of the linear tooth portion 204 like the tooth 203 of the embodiment shown in FIG. A meshing escape portion 208 that is notched from the surface to the vicinity of the tooth bottom surface may be formed, and the straight tooth portion 304 and the helical tooth portion 305 are formed like the tooth 303 of the embodiment shown in FIG. The engagement relief portions 308 and 308 that are notched from the tooth tip surface to the vicinity of the tooth bottom surface may be formed on the concave side tooth surface 303b of the continuous portion (two locations) 306, respectively. Furthermore, if the meshing relief portion 208 (308, 308) shown in FIGS. 7 and 8 is the concave tooth surface 203b (303b) of the linear tooth portion 204 (304), the arrangement, shape, and the like are particularly limited. Instead, a part of the meshing escape portion 208 (308) may be formed over the helical teeth 205 and 206 (305 and 306).

  Thus, the meshing relief portion 208 (308) is formed on the concave tooth surface 203b (303b) of the linear tooth portion 204 (304), so that the meshing state of the tooth 203 (303) can be made smoother. can do. In addition, the mesh escape portion 208 (308) can provide an effect of oil accumulation, and gear accuracy (machining accuracy) can be easily ensured in the case of electric discharge machining.

  Further, in the gear 1 of the above-described embodiment (see FIG. 1 and the like), the configuration in which the linear tooth portion 4 and the helical tooth portions 5 and 6 are integrally formed with one gear base portion 2 has been described. The configuration of the gear 1 is not limited to this. For example, the gear base 2 is composed of a plurality of members, and each member is formed with a linear tooth portion 4 and helical tooth portions 5 and 6, respectively, and then integrally formed. As a whole, it may be configured to be one gear 1 as a whole.

  Further, in the gear 1 of the above-described embodiment (see FIG. 1 and the like), the configuration in which the gear base 2 is formed in a cylindrical shape (circular gear) has been described. However, the shape of the gear 1 is not limited to this, for example, The gear base 2 may be formed in a non-circular shape or a flat plate shape. In particular, in the latter case, the gear 1 can be configured as a rack (linear gear), and can be used as a rack and pinion including a pair of circular gears and linear gears.

DESCRIPTION OF SYMBOLS 1 Gear 2 Gear base 2a Shaft hole 3 Tooth 3a Convex side tooth surface 3b Concave side tooth surface 4 Straight tooth part 5 Helical tooth part 6 Helical tooth part

That is, according to the first aspect of the present invention, the linear tooth portion formed at the center position in the tooth width direction and the both ends of the tooth width direction are formed, and the linear tooth portions are connected from both ends in the tooth width direction through continuous portions. The entire tooth width direction of the pair of helical teeth formed in a symmetrical shape with opposite twist directions and the straight teeth and the concave tooth surface of the continuous portion from the tooth tip surface. A tooth streak composed of one meshing escape portion formed by cutting out near the bottom surface has trapezoidal teeth, and the plurality of teeth are integrally molded on one gear base. is there.

That is, according to the first aspect of the present invention, it is configured as a circular gear having a gear base portion formed in a cylindrical shape having a circular cross section, and is formed at a central position in the tooth width direction, and a tooth line is a straight line parallel to the axis of the gear base portion. Linear teeth that are in the shape of a tooth, and are formed at both ends in the width direction of the tooth, continuous from both ends of the teeth in the width direction of the straight teeth through a continuous portion, and the tooth trace is relative to the axis of the gear base And a pair of helical teeth formed in a plane shape symmetrical with respect to the axis perpendicular to the center of the tooth width direction, and the concave tooth surface of the continuous portion. in the tooth width direction over the entire surface is to have a two meshing escape portion which is formed by notches over near the bottom land of the tooth crest, the plurality of teeth made of, circumferentially on the outer peripheral surface of the gear base portion wherein the plurality of teeth are integrally molded along and expand the outer peripheral surface of the gear base portion in the plane The linear teeth and the pair of the case are those represented by the shape the shape of the tooth trace are consecutive in helical Joha section respectively correspond to the upper base and the legs of the isosceles trapezoid.

Claims (6)

A straight tooth portion formed at the center position in the tooth width direction;
A pair of helical teeth with opposite torsional directions formed at both ends in the tooth width direction;
A trapezoidal toothed gear having a trapezoidal tooth.   2. The trapezoidal tooth according to claim 1, wherein the straight tooth portion has a tooth width direction length larger than a tooth pitch and smaller than a tooth width direction length of the helical tooth portion. Line gear.   3. The trapezoidal tooth helical gear according to claim 1, wherein the helical tooth portion is formed such that a tooth profile perpendicular to the axis has the same shape in a tooth width direction.   The trapezoidal tooth helical gear according to any one of claims 1 to 3, wherein the linear tooth portion is continuous with the helical tooth portion at both ends in a tooth width direction.   5. The meshing relief portion cut out from the tooth tip surface to the vicinity of the tooth bottom surface along the tooth width direction of the concave tooth surface of the linear tooth portion is formed according to claim 1. The trapezoidal toothed gear described.   6. The meshing relief portion cut out from the tooth tip surface to the vicinity of the tooth bottom surface is formed on the concave tooth surface of the continuous portion of the linear tooth portion and the helical tooth portion. A trapezoidal toothed gear according to claim 1.

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