JP2013190015A - Gear, and differential device - Google Patents

Abstract

A gear capable of suppressing the bending deformation by increasing the rigidity of teeth is provided.
A gear 30 includes circumferential ribs 34 and 35 extending in the circumferential direction so as to connect at least one end portions of adjacent teeth 33 in the length direction.
[Selection] Figure 7

Description

  The present invention relates to a differential device provided with a gear having high tooth rigidity and a high rigidity gear.

  The differential device is for giving a difference to the left and right drive wheels of an automobile so that it can bend easily. Typically, the differential device is arranged so as to mesh with a drive pinion connected to the input shaft and the drive pinion. A hypoid gear device including a ring gear is provided. The hypoid gear is disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-300423 (Patent Document 1), Japanese Patent Application Laid-Open No. 8-74967 (Patent Document 2), Japanese Patent Application Laid-Open No. 9-229167 (Patent Document 3), and the like. .

  An example of a differential device including a hypoid gear device is shown in FIG. The structure of a differential device including a conventional hypoid gear device will be described with reference to FIG. The differential device includes a drive pinion 1 connected to an input shaft (propeller shaft), a ring gear 2 disposed so as to mesh with the drive pinion 1, and a differential case 4 fixed to the back surface of the ring gear 2 via a bolt 3 or the like. The pinion shaft 5 held by the differential case 4, the pair of differential pinions 6 rotatably held by the pinion shaft 5, and the pair of side gears arranged to mesh with the pair of differential pinions 6 and connected to the left and right output shafts 7. The drive pinion 1 and the ring gear 2 constitute a hypoid gear device.

  The differential case 4 is rotatably supported by a differential carrier 10 via rolling bearings 8 and 9. The pinion shaft 5, the pair of differential pinions 6 and the pair of side gears 7 are accommodated in the differential case 4. FIG. 2 shows the drive pinion 1, and FIG. 3 shows the ring gear 2.

  The driving force from the input shaft is transmitted to the drive pinion 1, the ring gear 2, the differential case 4, the pinion shaft 5, the differential pinion 6, the side gear 7, and the output shaft in order. In the straight traveling state of the automobile, the pair of differential pinions 6 do not rotate but only revolve, so the pair of side gears 7 rotate in the same direction and at the same speed. When changing the advancing direction of the automobile, a difference in rotation occurs between the left and right side gears 7, and the pair of differential pinions 6 perform rotational movement. Therefore, cornering can be performed smoothly by absorbing the difference in rotation.

  In recent years, there has been a growing need for improved fuel economy and lower prices for automobiles. In order to meet this need, there is a high demand for weight reduction and high efficiency for a differential device that is a wheel drive mechanism. Since the main component of the differential device is a gear, if the gear is made smaller and lighter, the differential device can be made smaller and lighter.

  The gear teeth are typically formed by a gear cutter with a gear cutter. Japanese Patent Laying-Open No. 2005-238408 (Patent Document 4) discloses an apparatus and method for processing gear teeth on a workpiece with a gear cutter. FIG. 4 is a diagram showing the processing method disclosed in this publication.

  As shown in FIG. 4, the machining groove 22a for forming the first gear teeth 21a of the workpiece 20 includes a convex tooth surface machining blade 24a1 and a concave tooth surface machining blade 24b1 of the gear cutter 23. Are cut by a first pair of different blades 24a1b1. Subsequently, the processing groove 22b for forming the second gear tooth 21b is a second dissimilar combination of the convex tooth surface processing blade 24a2 and the concave tooth surface processing blade 24b2 which are arranged next. Cutting is performed by the blade pair 24a2b2. Then, the machining groove 22c for forming the next third gear tooth 21c is cut by the third dissimilar blade pair 24a3b3 arranged next. Thus, each gear tooth 21 is cut by each pair of different blades, so that the workpiece finally becomes a desired gear (face hob hypoid gear).

  FIG. 5 shows the pinion 1 after processing. As shown in FIG. 5, the locus of the blade 24 of the gear cutter 23 passes from the large-diameter end A of the pinion to the small-diameter end B, so that the tooth gap is between the adjacent teeth on the large-diameter end. To the end on the small diameter side.

JP 2003-300423 A JP-A-8-74967 JP-A-9-229167 JP-A-2005-238408

  If the gear size is reduced to reduce the size and weight of the differential device, the gear teeth will bend in the rotational direction or in the reverse direction due to the reaction force of the meshing portion between the gears at high loads, resulting in poor tooth contact. Stress may concentrate locally and lead to tooth breakage. This phenomenon will be described with reference to FIG.

  FIG. 6 schematically shows a meshing portion between the tooth 1 a of the drive pinion 1 and the tooth 2 a of the ring gear 2. (A) shows the drive pinion 1 rotating in the acceleration direction (forward rotation direction), and (b) the drive pinion 1 rotating in the deceleration direction (reverse rotation direction).

  In the case of the conventional drive pinion 1 in which the size of the gear is simply reduced, the rigidity of the teeth 1a becomes inferior. Therefore, when meshing with the teeth 2a of the ring gear 2 at a high load during acceleration, as shown in FIG. The tooth tip of the tooth 1a falls in the reverse rotation direction due to the reaction force of the meshing portion, and the tooth 1a bends and deforms, resulting in tooth root interference and tooth contact, so that the load is concentrated on a part of the tooth surface and is damaged. May lead to.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gear capable of suppressing the bending deformation by increasing the rigidity of the teeth.

  Another object of the present invention is to provide a differential apparatus including a high-rigid gear as a main component.

  The gear according to the present invention is characterized in that it includes a circumferential rib extending in the circumferential direction so as to connect at least one end portion in the length direction of adjacent teeth.

  Due to the presence of the circumferential ribs connecting the ends of the adjacent teeth, the bending deformation of the teeth can be suppressed even when the gears mesh with each other under a high load.

  Said circumferential rib may be provided only at one end in the length direction of adjacent teeth, or may be provided at both ends.

  The type of gear is not limited, but in one embodiment, a circumferential rib is provided on a pinion that meshes with a ring gear of a differential device. In another embodiment, a circumferential rib is provided on a ring gear that meshes with a drive pinion of a differential device. As still another embodiment, a circumferential rib may be provided on the spur gear.

  A differential device according to the present invention includes a gear device that includes a pinion and a ring gear arranged to mesh with the pinion, and at least one of the pinion and the ring gear is adjacent to the gear device. It is characterized by having a circumferential rib extending in the circumferential direction so as to connect at least one end portion in the length direction of the tooth to be performed.

  Since the pinion or ring gear provided with the circumferential rib is highly rigid even if it is reduced in size and weight, the entire differential device can be reduced in size and weight.

  In one embodiment, the pinion includes a circumferential rib and the ring gear does not include a circumferential rib. In other embodiments, the ring gear includes a circumferential rib and the pinion does not include a circumferential rib. In still another embodiment, the pinion includes circumferential ribs only at the small-diameter side end portions of both end portions thereof, and the ring gear includes circumferential ribs only at the outer-diameter side end portions thereof.

  In the embodiment described below with reference to the drawings, the pinion is a drive pinion connected to the input shaft. However, as another embodiment, the pinion may be a driven pinion connected to the output shaft. good. Moreover, although the differential apparatus provided with the combination of a pinion and a ring gear is demonstrated by the following embodiment, this invention is applicable also to the differential apparatus comprised with the parallel shaft gear mechanism.

  As described above, according to the present invention, it is possible to obtain a highly rigid gear capable of suppressing the bending deformation of teeth due to the presence of the circumferential rib. In addition, according to the differential device provided with such a high-rigidity gear as a main component, it is possible to reduce the size and weight. If it is the same size as the conventional one, the rigidity is dramatically increased, so that a differential device with more excellent transmission efficiency can be obtained.

It is sectional drawing of the conventional differential apparatus. It is a perspective view of a drive pinion. It is a perspective view of a ring gear. It is a figure which shows the processing method which forms a gear tooth in a workpiece with a gear cutter. It is a perspective view of the conventional drive pinion after processing with a gear cutter. It is a figure for demonstrating the problem of a prior art, and is a figure which shows typically the part which the tooth | gear of a drive pinion and the tooth | gear of a ring gear mesh | engaged. 1 is a perspective view of a drive pinion according to an embodiment of the present invention. It is a perspective view of the ring gear which concerns on other embodiment of this invention. It is a figure which shows the combination of the drive pinion with a circumferential rib and the ring gear without a circumferential rib as a hypoid gear apparatus. It is a figure which shows the combination of the drive pinion without a circumferential rib and the ring gear with a circumferential rib as a hypoid gear apparatus. It is a perspective view which shows the state which the spur gear without a circumferential rib and the spur gear with a circumferential rib mesh.

  As a typical embodiment, an example applied to a hypoid gear of an automobile differential device will be described.

  FIG. 7 shows a drive pinion 30 which is a main component of the hypoid gear device. The drive pinion 30 includes a shaft portion 31 and a truncated truncated cone-shaped head portion 32. A large number of teeth 33 and circumferential ribs 34 and 35 extending in the circumferential direction are formed at both ends of the teeth 33 in the length direction. One circumferential rib 34 is located at the small-diameter end and connects one end portion of the adjacent teeth 33, and the other circumferential rib 35 is located at the large-diameter end and is adjacent to the adjacent teeth 33. The other end portion is connected.

  In the illustrated embodiment, one circumferential rib 34 and one end portion of the tooth 33 have the same height, and the other circumferential rib 35 and the other end portion of the tooth 33 have the same height. Moreover, the outer peripheral surface of the circumferential ribs 34 and 35 is a smooth surface without unevenness. As another embodiment, the height of the circumferential ribs 34 and 35 may be slightly lower than the height of the end portion of the tooth 33, or may have an uneven outer peripheral surface.

  As a processing method of the drive pinion provided with the circumferential ribs 34 and 35, another method is adopted instead of the processing by the conventional gear cutting cutter. For example, end milling, machining by a machining center, sintering, etc. can be employed.

  In the embodiment shown in FIG. 7, the circumferential rib is provided at both one end and the other end of the tooth. However, as another embodiment, the circumferential rib is provided only at one end. You may do it. Because of the presence of the circumferential ribs connecting the ends of adjacent teeth, the bending deformation of the teeth is suppressed, so that a highly rigid drive pinion can be obtained.

  FIG. 8 shows a ring gear 40 which is a main component of the hypoid gear device. The ring gear 40 includes a plurality of radially extending teeth 41, an inner circumferential rib 42 that extends circumferentially at the inner diameter side end of the tooth, and an outer circumferential rib 43 that extends circumferentially at the outer diameter side end of the tooth. With. The inner circumferential rib 42 connects the end portions on the inner diameter side of the adjacent teeth 41 and suppresses bending deformation of each tooth 41. The outer circumferential rib 43 connects the outer diameter side end portions of the adjacent teeth 41 and suppresses the bending deformation of each tooth 41.

  In the illustrated embodiment, the inner circumferential rib 42 and the inner diameter side end of the tooth 41 have the same height, and the outer circumferential rib 43 and the outer diameter side end of the tooth 41 have the same height, The surfaces of the peripheral ribs 42 and 43 are smooth surfaces without irregularities. As another embodiment, the height of the circumferential ribs 42 and 43 may be slightly lower than the height of the end portion of the tooth 41, or may have an uneven surface. As a processing method of the ring gear 40 provided with the circumferential ribs 42 and 43, for example, end mill processing, processing by a machining center, sintering processing, or the like can be employed.

  In the embodiment shown in FIG. 8, the circumferential rib is provided at both the inner diameter side end and the outer diameter side end of the tooth 41. However, as another embodiment, the circumferential rib is provided only at one end. You may do it.

  A differential device to which the present invention is applied includes a hypoid gear device including a drive pinion connected to an input shaft and a ring gear arranged so as to mesh with the drive pinion. , And at least one of the drive pinion and the ring gear is provided with a circumferential rib extending in the circumferential direction so as to connect at least one end portion in the length direction of adjacent teeth. .

  FIG. 9 shows an example in which a hypoid gear device is configured by a combination of a drive pinion 50 having circumferential ribs at both ends in the tooth length direction and a ring gear 60 not having circumferential ribs. In FIG. 10, a hypoid gear device is configured by a combination of a drive pinion 70 not provided with a circumferential rib and a ring gear 80 provided with a circumferential rib on both the inner diameter side end portion and the outer diameter side end portion of the tooth. An example is shown.

  Although not shown in the drawings, as another example, a drive pinion provided with a circumferential rib only at the small-diameter side end portion of both end portions of the tooth, and a circumferential rib only at the outer-diameter end portion of both end portions of the tooth. You may make it comprise a hypoid gear apparatus with the combination with the provided ring gear. Since the tooth thickness at the small-diameter end of the drive pinion is smaller than the large-diameter end, a circumferential rib is provided only at the small-diameter end in order to suppress bending of the teeth at the small-diameter end that is more flexible. Is meaningful.

  In the case of the hypoid gear device, if the offset amount is set to zero, the slippage at the meshing portion of the teeth is eliminated, so that the transmission efficiency is increased. On the other hand, if the offset amount is set to zero, it is necessary to increase the strength of the gear. In order to increase the strength of the gear, it is necessary to increase the offset amount. If the offset amount increases, slippage at the meshing portion of the teeth increases and transmission efficiency becomes inferior. With the hypoid gear device having a gear having a circumferential rib according to the present invention, even if the gear is reduced in size and weight, it is possible to realize a high rigidity by suppressing the bending deformation of the teeth. The transmission efficiency can be increased, and the fuel efficiency of the vehicle can be improved. In addition, since the meshing error can be reduced as the rigidity is increased, noise can be reduced. Furthermore, since the circumferential rib exists, the heat treatment distortion of the gear can be reduced.

  The type of gear provided with the circumferential rib for suppressing the bending deformation of the teeth is not limited to the drive pinion and the ring gear of the hypoid gear device, and can be applied to other types of gears. FIG. 11 shows an example in which the present invention is applied to a spur gear. FIG. 11 shows a state where the large-diameter gear 90 and the small-diameter gear 100 are meshed with each other. Although the small-diameter gear 100 does not include the circumferential rib, the large-diameter gear 90 includes the circumferential ribs 92 and 93 that extend in the circumferential direction so as to connect the teeth adjacent to both ends of the teeth 91 in the length direction. . Due to the presence of the circumferential ribs 92 and 93, bending deformation of each tooth 91 of the large-diameter gear 90 is suppressed.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The present invention can be advantageously used as a high-rigidity gear suitable for reduction in size and weight, and as a differential device suitable for reduction in size and weight.

  1 drive pinion, 1a tooth, 2 ring gear, 2a tooth, 3 bolt, 4 differential case, 5 pinion shaft, 6 differential pinion, 7 side gear, 8, 9 rolling bearing, 10 differential carrier, 20 workpiece, 21a, 21b, 21c gear Teeth, 22a, 22b, 22c Machining groove, 23 Gear cutting cutter, 24a1, 24a2, 24a3 Convex tooth surface processing blade, 24b1, 24b2, 24b3 Concave tooth surface processing blade, 30 Drive pinion, 31 Shaft part, 32 heads Part, 33 teeth, 34, 35 circumferential rib, 40 ring gear, 41 teeth, 42, 43 circumferential rib, 50 drive pinion, 60 ring gear, 70 drive pinion, 80 ring gear, 90 large diameter spur gear, 91 teeth, 92, 93 circumferential rib, 100 small diameter spur gear.

Claims (8)

  A gear provided with a circumferential rib extending in the circumferential direction so as to connect at least one end portion in the length direction of adjacent teeth.   The gear according to claim 1, wherein the circumferential rib is provided at both one end portion and the other end portion in the length direction of adjacent teeth.   The gear according to claim 1, wherein the gear is a pinion that meshes with a ring gear.   The gear according to claim 1, wherein the gear is a ring gear that meshes with a pinion. In a differential device including a gear device composed of a pinion and a ring gear arranged to mesh with the pinion,
At least one of the pinion and the ring gear includes a circumferential rib extending in the circumferential direction so as to connect at least one end portion in the length direction of adjacent teeth. , Differential equipment.   The differential device according to claim 5, wherein the pinion includes the circumferential rib, and the ring gear does not include the circumferential rib.   The differential device according to claim 5, wherein the ring gear includes the circumferential rib, and the pinion does not include the circumferential rib. The pinion includes the circumferential rib only at the small diameter side end portion of the both end portions,
The differential device according to claim 5, wherein the ring gear includes the circumferential rib only at an outer diameter side end portion of both end portions thereof.

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