JP2012215258A - Meshing gear device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a meshing gear device of a vehicle, which is composed of a pair of helical gears, and can suppress tooth face wear and suppress gear noise.SOLUTION: A tooth face in a meshing start part of a drive gear 68 is cut off, and the apex O2 of a convex curved surface shape formed on the tooth face of the drive gear 68 is set in a position away from the cut-out 80 (meshing start part) so that the meshing in the meshing start part is eliminated by the cut-out 80 formed on the tooth face that corresponds to the meshing start part, thereby suppressing the tooth face wear. Moreover, since the apex O2 of the convex curved surface shape formed on the tooth face 68a of the drive gear 68 is set in a position away from the meshing start part, tooth contact 82 necessary for a gear noise performance can be secured which enables the suppression of gear noise.

Description

  The present invention relates to a meshing gear device of a vehicle that is provided in a power transmission path between an engine and driving wheels and is configured by a pair of helical gears that mesh with each other, and in particular, gear noise that is generated when meshing gears. And a technique for suppressing tooth surface wear.

  2. Description of the Related Art A meshing gear device for a vehicle is well known that includes a pair of helical gears that are provided in a power transmission path between an engine and driving wheels and mesh with each other. For example, in a differential gear (differential gear device) of an FF transmission, a final drive gear (drive gear) that is a driving side gear and a final driven gear (driven gear) that is a driven side gear are configured by helical gears. Yes. In such a meshing gear device, power is often transmitted at a high load and a high sliding speed, and tooth surface wear is likely to occur at the tooth base start portion of the drive gear, and tooth surface wear is also likely to occur due to trochoidal interference. Become. When this tooth surface wear occurs, the tooth contact, which is the area (contact area) where the tooth surfaces mesh with each other, deteriorates, and the mesh transmission error that becomes the vibration source of the gear noise increases, so the gear noise increases. The meshing transmission error is an error (delay or advance) of the rotational displacement of the driven gear with respect to the rotational displacement of the drive gear at the time of gear meshing. Trochoid interference is a phenomenon in which the drive gear and driven gear mesh at a position deviating from the ideal meshing point due to the elastic deformation of the gear that occurs during high loads, and this trochoid interference causes tooth surface wear. It is known to be.

  On the other hand, in Patent Document 1, for example, in a helical gear having a reference tooth surface having an involute curve as a tooth shape and transmitting a high load, and having a long tooth width, the shape of the tooth shape is meshed on the tooth surface. It is described that, by applying a bias modification with a waveform shape that varies from the initial part to the involute curved surface and having a waveform shape that varies depending on the position of the tooth trace direction, meshing is performed without generating a large impact at the beginning of meshing and power is transmitted. Thereby, the tooth surface wear is suppressed by suppressing the impact generated at the beginning of meshing.

JP-A-8-285048 JP-A-10-89442

  By the way, in the helical gear of Patent Document 1, although the tooth surface wear is suppressed by applying bias correction at the meshing start portion on the tooth surface, the tooth surface of the tooth surface is suppressed by the bias correction at the time of gear engagement. There was a possibility that the tooth contact was not sufficiently secured. It is known that the tooth contact corresponds to an area where the gears come into contact with each other when the gears mesh with each other, and if the tooth contact does not secure a predetermined value, it causes gear noise. Therefore, even with the helical gear of Patent Document 1, there is a possibility that gear noise may occur due to insufficient tooth contact of the tooth surface.

  The present invention has been made in the background of the above circumstances, and its object is to suppress tooth surface wear in a meshing gear device for a vehicle composed of a pair of helical gears meshing with each other. An object of the present invention is to provide a meshing gear device for a vehicle that can suppress gear noise.

  In order to achieve the above object, the gist of the invention according to claim 1 is as follows: (a) a power transmission path between the engine and the drive wheels, and a pair of helical gears meshing with each other; (B) The tooth surfaces of the pair of helical gears are formed in a convex curved surface shape having a predetermined curvature in the toothing direction and the tooth width direction, and (c) In a pair of helical gears, the tooth surface of the engagement start portion of at least one gear is cut out, and the vertex of the convex curved surface formed on at least one gear of the pair of helical gears Is set at a position away from the meshing start portion.

  In this case, in the pair of helical gears, the tooth surfaces of the meshing start portion of at least one gear are cut out, and formed on at least one gear of the pair of helical gears. The apex of the convex curved surface shape is set at a position away from the engagement start portion. If it does in this way, with the notch formed in the tooth surface of a meshing start part, meshing of a meshing start part can be eliminated and tooth surface wear can be controlled. In addition, since the apex of the convex curved surface formed on at least one of the helical gears is set at a position away from the meshing start portion, the tooth contact necessary for gear noise performance can be ensured. The gear noise can be suppressed.

  Preferably, the apex of the convex curved surface formed on the tooth surfaces of the pair of helical gears secures the tooth contact necessary for gear noise performance when the pair of helical gears mesh with each other. As far as possible, it is separated from the meshing start portion. In this way, when the pair of helical gears mesh with each other, the tooth contact necessary for gear noise performance is ensured, so that gear noise can be suppressed even when a high load is applied to the meshing gear device.

  Preferably, when the drive side gears of the pair of helical gears are notched, the tooth surfaces on the side where meshing is started in the tooth width direction of the tooth base of the drive side gears are partially recessed. Notched. In this way, when the pair of helical gears mesh with each other, the tooth base side of the drive side gear becomes the meshing start portion. Accordingly, the meshing at the meshing start portion can be eliminated by cutting out a part of the tooth surface on the tooth base side so as to be recessed.

  Preferably, when the driven side gears of the pair of helical gears are notched, the tooth surfaces on the side where the meshing is started in the tooth width direction of the tooth tips of the driven side gears are partially recessed. Notched like so. In this way, when the pair of helical gears mesh with each other, the tooth tip side of the driven gear becomes the meshing start portion. Therefore, the meshing at the meshing start portion can be eliminated by cutting out a part of the tooth surface on the tooth tip side so as to be recessed.

1 is a skeleton diagram for explaining an outline of a power transmission device of a hybrid vehicle to which the present invention is applied. It is a figure for demonstrating the shape of the drive gear of the conventional shape in FIG. In FIG. 1, it is a figure for demonstrating the shape of the drive gear of this invention. FIG. 4 is a diagram showing a calculation result obtained by calculating a load applied to a tooth surface when meshing with a driven gear is started in the drive gear of FIGS. 2 and 3. FIG. 4 is a diagram showing a mesh transmission error that occurs when the drive gear of FIGS. 2 and 3 meshes with a driven gear. It is the figure which showed the combination of the gearwheel in which the position of the gearwheel in which a notch is formed, and the vertex of a convex curve shape is changed. It is a figure which shows the shape of the gearwheel in case a notch is formed in the driven gear side of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a skeleton diagram for explaining an outline of a power transmission device 10 (hereinafter referred to as a power transmission device 10) of a hybrid vehicle to which the present invention is applied. As shown in FIG. 1, the power transmission device 10 is connected to the engine 12, the first electric motor MG1, and the engine 12 and the first electric motor MG1 so as to be able to transmit power, and appropriately applies the driving force of the engine 12 and the first electric motor MG1. A first planetary gear unit 14 serving as a power distribution mechanism for distributing or combining, a second electric motor MG2, and a second planetary gear unit 18 functioning as a reduction gear that decelerates the rotation of the second electric motor MG2 are arranged on a coaxial center C. It is configured to prepare for. The driving force of the engine 12 is transmitted to the drive wheels 28 through the damper device 20, the first planetary gear device 14, the output gear 22, the reduction gear device 24, the differential gear device 26, and the left and right axles 27. A mechanical oil pump 19 that is actuated by rotation of the output shaft 16 of the engine 12 is connected to the end of the engine 12 opposite to the axial direction. As described above, the engine 12, the first electric motor MG1, the first planetary gear device 14, the second planetary gear device 18, and the second electric motor MG2 are arranged on the axis C, so that the power transmission device 10 is in the radial direction. Downsized.

  The first motor MG1 and the second motor MG2 are so-called motor generators that also have a power generation function, but the first motor MG1 that functions as a differential motor for controlling a differential state as a power distribution mechanism is: At least a generator (power generation) function for generating a reaction force is provided. The second electric motor MG2 connected to the drive wheel 28 so as to be able to transmit power is provided with at least a motor (electric motor) function in order to function as a traveling motor that outputs a driving force as a driving force source for traveling. Further, the second electric motor MG2 mainly functions as a driving force source for traveling, and thus is larger than the first electric motor MG1.

  The first electric motor MG1 is arranged on the coaxial core C on the outer peripheral side of the cylindrical rotor 36 functioning as a rotor whose both ends in the axial direction are rotatably supported by the bearings 32 and 34. It includes a cylindrical stator 38 that functions as a stator that is non-rotatably fixed by a case 30 that is a non-rotating member.

  The second electric motor MG <b> 2 is disposed on the coaxial core C so as to function as a stator that is fixed to be non-rotatable by being connected to the case 30, and is disposed on the inner peripheral side of the stator 40 and rotates. A cylindrical rotor 42 that functions as a child is included. A cylindrical rotating shaft 48 is connected to the inner peripheral side of the rotor 42. Both ends of the rotating shaft 48 are rotatably supported by the bearing 50 and the bearing 52, so that the rotating shaft 48 is rotatably supported around the axis C as in the rotor 42 connected to the rotating shaft 48. Further, an end portion on the engine 12 side in the axial direction of the rotating shaft 48 is connected to a sun gear S2 described later of the second planetary gear unit 18.

  The first planetary gear unit 14 is composed of a single pinion type planetary gear unit, and rotates the sun gear S1, the ring gear R1 coaxially arranged with the sun gear S1 and meshed with the sun gear S1 via the pinion gear P1, and the pinion gear P1. And a carrier CA1 that is revolved. The sun gear S1 of the first planetary gear unit 18 is coupled to the rotor 36 of the first electric motor MG1, the carrier CA1 is coupled to the engine 12 via the output shaft 16 and the damper unit 20, and the ring gear R1 is coupled to the output gear 22 and the reduction gear. It is mechanically connected to the left and right drive wheels 28 via a gear device 24, a differential gear device 26, and left and right axles 27.

  The second planetary gear unit 18 is arranged side by side in the axial direction around the axis C common to the first planetary gear unit 14, and functions as a mechanism that decelerates and outputs the rotation of the second electric motor MG2. The second planetary gear unit 18 is composed of a single pinion type planetary gear unit, and rotates the sun gear S2, the ring gear R2 coaxially arranged with the sun gear S2 and meshed with the sun gear S2 via the pinion gear P2, and the pinion gear P2. And a carrier CA2 that is revolved. Then, the sun gear S2 of the second planetary gear device 20 is connected to the rotor 42 of the second electric motor MG2 via the rotating shaft 48, the carrier CA2 is connected to the case 30 that is a non-rotating member, and the ring gear R2 is the same as the ring gear R1. In addition, it is mechanically connected to the left and right drive wheels 28 via an output gear 22, a reduction gear device 24, a differential gear device 26, and an axle 27. Then, the rotation of the second electric motor MG2 input from the sun gear S2 is decelerated and output from the ring gear R2.

  In this embodiment, the inner teeth of the ring gear R1 of the first planetary gear unit 18 and the inner teeth of the second ring gear R2 are formed on the inner circumference side by side in the axial direction, and the outer teeth of the output gear 22 are arranged on the outer circumference side. A so-called compound type compound gear 54 in which teeth are formed is used. As described above, the power transmission device 10 is made compact by integrating a plurality of gear functions in the compound gear 54.

  The reduction gear device 24 includes a counter driven gear 64 that meshes with the output gear 22 (counter drive gear) on the counter shaft 62, and a final drive gear 68 that meshes with the final driven gear 66 of the differential gear device 26. Is decelerated and transmitted to the final driven gear 66. Note that the counter shaft 62 is rotatably supported by a pair of bearings 69 and 71, and each gear is composed of inclined teeth. In addition, the final drive gear 68 of the reduction gear device 24 and the final driven gear 66 of the differential gear device 26 mesh with each other, so that the pair of meshing gears of the present invention that are provided in the power transmission path between the engine 12 and the drive wheels 28 are as follows. A helical gear, that is, a meshing gear device for a vehicle is configured.

  The differential gear device 26 is a known bevel gear type, and includes a differential case 70 connected to the final driven gear 66 of the differential gear device 26, a pinion shaft 72 supported at both ends by the differential case 70, A pinion gear 74 that is inserted through the pinion shaft 72 and is relatively rotatable about the rotation axis of the pinion shaft 72, and a pair of side gears 76 that mesh with the pinion gear 74 are provided. The pair of side gears 76 are integrally rotated by being spline fitted to the left and right axles 27, respectively. Due to the differential action of the differential gear device 26, a rotational difference is given to the left and right axles 27 (drive wheels 28) according to the traveling state of the vehicle.

  Here, the final drive gear 68 (hereinafter referred to as drive gear 68) of the reduction gear device 24 and the final driven gear 66 (hereinafter referred to as driven gear 66) of the differential gear device 26 are respectively formed as helical gears, and have a reduction ratio. Therefore, a large load (high load) is easily applied to these meshing portions. As a result, tooth surface wear occurs at the meshing start portion (tooth base) of the drive gear 68, and the tooth contact of the tooth surface is deteriorated due to the tooth surface wear, so that gear noise may increase. Here, the tooth contact of the tooth surface corresponds to an area that contacts when the gears mesh with each other, and when the tooth contact deteriorates (decreases), the engagement transmission error TE that becomes a vibration source of gear noise deteriorates. It is known. Accordingly, the gear noise performance is ensured, in other words, the tooth contact where the gear noise is less than the allowable value is set in advance, and the tooth surface shape is designed so as to ensure the tooth contact. The mesh transmission error TE is an error (= X1−X2) between the rotational displacement X1 of the drive gear 68 that is the driving side gear and the rotational change X2 of the driven gear 66 that is the driven side gear. When the meshing transmission error TE increases, the gear noise excitation force increases and the gear noise deteriorates.

  The above problem will be described more specifically using a conventional drive gear 68 '(conventional product) shown in FIG. FIG. 2A is an enlarged view of the tooth portion of the gear of the conventional drive gear 68 '. Since the drive gear 68 ′ is constituted by a helical gear, as shown in FIG. 2A, when the drive gear 68 ′ meshes with the driven gear 66, from the tooth base side toward the tooth tip side. Power is transmitted while contacting diagonally. FIG. 2B is a projection view of the tooth surface 68'a shown in FIG. In FIG. 2 (b), a plurality of diagonal lines drawn by a broken line indicate simultaneous contact lines. The simultaneous contact line indicates a portion that contacts the driven gear 66 simultaneously when engaged with the driven gear 66. As shown in FIG. 2 (b), the tooth surfaces 68'a of the drive gear 68 'are not all in contact with the tooth surfaces of the driven gear 66 at the same time, and the meshing start is surrounded by an ellipse drawn with a broken line. The contact portion moves obliquely toward the tooth tip side. This is because the drive gear 68 and the driven gear 66 are helical teeth. FIG. 2 (c) shows the shape of the tooth surface 68'a shown in FIG. 2 (b) in more detail. The parabola (arc, quadratic curve) shown on the upper side and the right side shown in FIG. 2 (c) indicates the convex curved surface shape formed on the tooth surface 68 ′ of the tooth surface 68. More specifically, the parabola shown on the upper side corresponds to the AA ′ cross-sectional view, and the tooth surface 68′a has a convex curved surface shape with a predetermined curvature with the vicinity of the center as the vertex O1 in the tooth width direction. It is shown that it is formed. Further, the parabola shown on the right side corresponds to the BB ′ cross-sectional view, and is formed in a convex curved surface shape with a predetermined curvature with the vicinity of the center as a vertex O1 in the direction of toothing of the tooth surface 68′a. It shows that. That is, it is shown that the vicinity of the center portion of the tooth surface 68'a is formed as a convex curved surface with the vertex O1. Note that the parabolas shown on the upper and right sides of FIG. 2 (c) are both greatly described to show that the tooth surface 68'a is formed in a convex curved surface shape. It is formed in a very small convex curved surface shape of a unit of several to several tens of micrometers. And it is designed so that the part shown with the oblique line enclosed by the ellipse centering | focusing on the vertex O1 of this convex curve shape may become a tooth contact. This tooth contact (area) is set in advance based on experiments or the like so that the gear noise is less than the allowable value.

  In such a conventional drive gear 68 ′, when a high load is applied to the driven gear 66, tooth surface wear occurs in the shaded portion surrounded by the triangle in FIG. To do. Here, as shown in FIG. 2 (c), a portion where tooth surface wear is formed (a portion surrounded by a triangle) and a portion where tooth contact is set (a portion surrounded by an ellipse) overlap. When tooth surface wear occurs, the tooth contact is reduced by the overlapping area. As a result, the tooth contact cannot be made only in the area necessary for the preset gear noise performance, so that the meshing transmission error TE between the drive gear 68 ′ and the driven gear 66 increases, and as a result, the gear noise increases. There was a possibility.

  Next, the drive gear 68 of the present invention is shown in FIG. In the drive gear 68, as shown in FIG. 3A, a portion corresponding to a meshing start portion that is a part of the tooth base is cut out on the tooth surface 68a that meshes with the driven gear 66 when power is transmitted. Thus, a notch 80 is formed. When the tooth surface 68a is viewed on the projection unit, it is as shown in FIG. As shown in FIGS. 3A and 3B, the notch 80 is formed by notching the tooth surface 68a on the side where the meshing is started in the tooth width direction of the tooth base of the drive gear 68 so as to be recessed. ing. The notch 80 is formed, for example, along the simultaneous contact line of the tooth surface 68a, and is notched within a range in which a predetermined strength that can cope with a high load applied to the drive gear 68 is secured.

  Further, as shown in FIG. 3B, in the convex curved surface shape having a predetermined curvature in the tooth direction and the tooth width direction formed on the tooth surface 68a of the drive gear 68, the vertex O2 of the convex curved surface shape is 2 is set at a position farther from the notch 80 (meshing start portion) than the vertex O1 of the drive gear 68 ′ (conventional) shown in FIG. 2 where the notch 80 is not formed. Specifically, the vertex O2 of the convex curved surface is on the tooth tip side with respect to the vertex O1 of the convex curved surface of the drive gear 68 ′ corresponding to the conventional one, and from the meshing start portion in the tooth width direction. The side has been changed. That is, the vertex O2 is changed from the vertex O1 to the traveling direction side (meshing end side) at the time of meshing. As shown in FIG. 2 (c), the vertex O1 of the drive gear 68 'is substantially the center of the tooth surface 68'a, so that the vertex O2 of the drive gear 68 starts to engage more than the center portion of the tooth surface. The position is away from the portion (notch 80).

  Thus, when the vertex O2 of the convex curved surface is set at a position farther from the meshing start portion (notch 80) than the vertex O1 when the notch 80 is not formed, the tooth contact 82 surrounded by an ellipse is provided. Is located away from the notch 80 (meshing start portion). Accordingly, as shown in FIG. 3B, the tooth contact 82 surrounded by the ellipse is set at a position that does not overlap with the notch 80 surrounded by the triangle. Here, even if the vertex O2 of the convex curved surface shape moves, the area of the tooth contact 82 is set so as not to be different from the conventional tooth contact shown in FIG. That is, the vertex O2 is set at a position away from the meshing start portion within a range in which the tooth contact 82 necessary for the gear noise performance is ensured.

  When the drive gear 68 is formed in this way, even if the engagement with the driven gear 66 starts, the engagement is avoided at the engagement start portion by the notch 80 of the drive gear 68. That is, since the notch 80 is formed in advance at the meshing start portion where tooth surface wear is likely to occur at high loads, tooth surface collision at the meshing start portion is prevented, and tooth surface wear is suppressed. On the other hand, the formation of the notch 80 causes a problem that the area of the tooth contact 82 is reduced. However, in the drive gear 68 of the present embodiment, a convex curved surface is provided so that the area of the tooth contact 82 is ensured. Since the vertex O2 of the shape is set at a position away from the meshing start portion, the influence of the notch 80 does not occur. That is, the gear noise performance that is substantially the same as that of the drive gear 68 ′ in which the notch 80 shown in FIG. 2 is not formed can be obtained.

  FIG. 4 shows a load F (N) applied to the tooth surface when the engagement with the driven gear 66 is started in the drive gear 68 ′ (conventional product) shown in FIG. Only a part of the calculation result is shown. In FIG. 4, the horizontal axis indicates the position of the tooth tip to the tooth tip, and the vertical axis indicates the load F applied to the position of the tooth surface. Also, the black diamonds indicate the load F (calculation result) of the drive gear 68 ′ (conventional product) in FIG. 2 where the notch 80 is not formed, and the black triangles indicate the load F applied to the drive gear 68 of the present invention. (Calculation results) are shown. As shown in FIG. 4, in the conventional driven gear 68 ′, the load F shows a very high value at the tooth root, that is, at the meshing start portion. On the other hand, since the notch 80 is formed in the drive gear 68 of the present invention, the load F becomes zero because it does not mesh with the driven gear 66 in the vicinity of the tooth root (meshing start portion). The meshing is started from the position where the cutout 80 has passed. As shown in FIG. 5, the load F is smaller than that of the conventional product in the region where the engagement start portion is removed, and tooth surface wear is also suppressed.

  FIG. 5 shows a meshing transmission error TE (dB) generated in the drive gear 68 '(conventional product) in FIG. 2 in which the notch 80 is not formed and the drive gear 68 of the present invention. When the meshing transmission error TE increases, the gear noise excitation force increases and the gear noise increases. As shown in FIG. 5, the mesh transmission error TE hardly changes even when the conventional product and the present invention are compared. This is because the tooth contact 82 set for the drive gear 68 is set to a value that is not different from the tooth contact of the drive gear 68 '.

  As described above, according to the present embodiment, in the meshing gear device constituted by the drive gear 68 and the driven gear 66 which are helical teeth, the tooth surface of the meshing start portion of the drive gear 68 is cut out, and Further, the vertex O2 of the convex curved surface formed on the tooth surface of the drive gear 68 is set at a position away from the notch 80 (meshing start portion). By doing so, the notch 80 formed in the tooth surface corresponding to the meshing start portion can eliminate the meshing of the meshing start portion and suppress tooth surface wear. Further, since the convex curved surface apex O2 formed on the tooth surface 68a of the drive gear 68 is set at a position away from the meshing start portion, the tooth contact 82 necessary for the gear noise performance can be secured. The gear noise can be suppressed.

  In addition, according to the present embodiment, the convex-curved vertex O2 formed on the tooth surface 68a of the drive gear 68 is within a range in which the tooth contact necessary for the gear noise performance is ensured when meshing with the driven gear 66. Separated from the meshing start. In this way, when the drive gear 68 and the driven gear 66 mesh with each other, the tooth contact necessary for the gear noise performance is ensured, so that gear noise can be suppressed even when a high load is applied between them.

  Further, according to the present embodiment, when the drive gear 68 that is the drive side gear is notched, the tooth surface 68a on the side where the engagement starts in the tooth width direction of the tooth base of the drive gear 68 is partially recessed. Notched into. In this way, when the drive gear 68 and the driven gear 66 mesh with each other, the tooth base of the drive gear 68 becomes the meshing start portion. Therefore, the engagement at the meshing start portion can be eliminated by cutting out a part of the tooth surface on the tooth base side of the drive gear 68 so as to be recessed.

  Next, another embodiment of the present invention will be described. In the following description, parts common to those in the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  In the above-described embodiment, in the final drive gear 68 that is the drive side gear, the notch 80 is formed and the vertex O2 of the convex curved surface is set at a position away from the meshing start portion. It is not necessary to configure. For example, the vertex O2 of the drive gear 68 may be set at a position away from the engagement start portion, while a notch may be formed on the driven gear 66 side. Even in such a mode, the meshing start portion is not meshed and the tooth contact is sufficiently ensured, so that the same effect as in the above-described embodiment can be obtained. That is, the same effect as the above-described embodiment can be obtained as long as at least one of the notch and the vertex of the convex curved surface is changed. FIG. 6 is a list showing combinations of gears that form notches and gears that move the apex of the convex curved surface shape away from the meshing start portion. Even when it is implemented in each combination as shown in FIG. 6, the same effect as the above-described embodiment can be obtained.

  A mode 1 shown in FIG. 6 corresponds to the above-described embodiment. Specifically, in the aspect 1, the notch 80 is formed on the drive gear 68 side, and the vertex of the drive gear 68 is changed. Further, in the aspect 2, the apex on the drive gear 68 side is moved, while the notch 90 is formed on the driven gear 66 side. Here, when the driven gear 66 side which is the driven side gear is cut away, as shown in FIG. 7, the tooth surface 66a on the side where the meshing is started in the tooth width direction of the tooth tip is cut out so as to be recessed. A notch 90 is formed. This is because in the driven gear 66, the meshing start portion when meshing with the drive gear 68 is the tooth tip side.

  In mode 3, the top of the convex curved surface shape of the driven gear 66 is moved, while the notch 80 is formed in the drive gear 68. Similarly, the apex of the driven gear 66 is set in a direction away from the engagement start portion, that is, the portion where the notch 90 is formed. Even in this case, it is set in a range in which the tooth contact necessary for the gear noise characteristic is secured. Aspect 4 is an aspect in which the notch 90 is formed in the driven gear 66 while the vertex of the convex curved surface shape of the driven gear 66 is moved.

  Further, the aspect 5 is an aspect in which notches 80 are formed in the drive gear 68 while the vertices of the convex curved surfaces of the drive gear 68 and the driven gear 66 are moved. Even if the vertices of the convex curved surfaces of both the drive gear 68 and the driven gear 66 are changed as in the aspect 5, the same effect as in the above-described embodiment can be obtained. Aspect 6 is an aspect in which notches 90 are formed in the driven gear 66 while the vertices of the convex curved surfaces of the drive gear 68 and the driven gear 66 are moved.

  Aspect 7 is an aspect in which notches 80 and 90 are formed in the drive gear 68 and the driven gear 66 while the vertex of the convex curved shape of the drive gear 68 is moved. Thus, even if the notches 80 and 90 are formed in both the drive gear 68 and the driven gear 66, the same effect as in the above-described embodiment can be obtained. Aspect 8 is an aspect in which notches 80 and 90 are formed in the drive gear 68 and the driven gear 66 while the vertex of the convex curved shape of the driven gear 66 is moved. Aspect 9 is an aspect in which notches 80 and 90 are formed in the drive gear 68 and the driven gear 66 while the vertices of the convex curved surfaces of the drive gear 68 and the driven gear 66 are moved. In any of these modes 1 to 9, since the meshing at the meshing start portion is avoided by the notch and the apex of the convex curved surface is moved, the tooth contact 82 is ensured. The same effect as the example can be obtained.

  As described above, according to the present embodiment, even when the movement of the notch and the vertex of the convex curved surface is performed on at least one of the drive gear 68 and the driven gear 66, the same effect as the above-described embodiment can be obtained. Obtainable.

  Further, according to the present embodiment, when the driven gear 66 that is the driven side gear is cut away, the tooth surface 66a on the side where the meshing is started in the tooth width direction of the tooth tip of the driven gear 66 is partially recessed. Notched. In this way, when the drive gear 68 and the driven gear 66 mesh with each other, the tooth tip of the driven gear 66 becomes the meshing start portion. Therefore, the meshing at the meshing start portion can be eliminated by cutting out a part of the tooth surface 66a of the tooth tip of the driven gear 66 so as to be recessed.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, a pair of gears (meshing gear device) constituted by the final drive gear 68 of the reduction gear device 24 and the final driven gear 66 of the differential gear device 26 has been described as an example. The present invention is not limited to the final drive gear 68 and the final driven gear 66, and can be appropriately applied as long as it is a meshing gear device composed of helical teeth that transmit power.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

12: Engine 28: Drive wheel 66: Final driven gear (helical gear, driven side gear, meshing gear device)
68: Final drive gear (helical gear, drive side gear, meshing gear device)
80, 90: notch 82: tooth contact O2: apex

Claims (4)

In a meshing gear device for a vehicle, which is provided in a power transmission path between an engine and a drive wheel and includes a pair of helical gears that mesh with each other,
The tooth surfaces of the pair of helical gears are formed in a convex curved surface shape having a predetermined curvature in the tooth direction and the tooth width direction,
In the pair of helical gears, the tooth surface of the engagement start portion of at least one gear is cut out, and the convex curved surface shape formed on at least one gear of the pair of helical gears. A meshing gear device for a vehicle, wherein a vertex is set at a position away from the meshing start portion.   The vertices of the convex curved surface formed on the tooth surfaces of the pair of helical gears are meshed within a range in which the tooth contact necessary for gear noise performance is secured when the pair of helical gears mesh. The meshing gear device for a vehicle according to claim 1, wherein the gearing gear device is separated from the starting portion.   When the drive side gears of the pair of helical gears are notched, the tooth surfaces on the side where meshing is started in the tooth width direction of the tooth base of the drive side gears are notched so as to be partially recessed. The meshing gear device for a vehicle according to claim 1 or 2.   When the driven gears of the pair of helical gears are notched, the tooth surfaces on the side where the meshing is started in the tooth width direction of the tooth tips of the driven gears are notched so as to be partially recessed. The meshing gear device for a vehicle according to claim 1 or 2.

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