JP2018189182A - Gear housing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear housing that can check deterioration in tooth flank after use separately from an assembly work.SOLUTION: A gear housing accommodating one drive-side gear and one or more driven-side gears rotating by receiving power directly or indirectly from the drive-side gear as a driving source is provided with a hole for checking at least one tooth flank of the driven-side gears from an upstream side in a rotation direction of the driven-side gears.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gear housing that houses a plurality of gears including one drive side gear.

  2. Description of the Related Art Conventionally, in a vehicle internal combustion engine, rotation of a crankshaft is transmitted to a driving gear, and power is transmitted by one or more driven gears that rotate by receiving power directly or indirectly from the driving gear. It is known what has been configured.

  In such power transmission, it is desirable to cover the gear with a gear housing in order to prevent the gear from being exposed to the atmosphere. At this time, if each gear is covered with the gear housing, each gear becomes invisible.

  For this reason, for example, as in the case of confirming the phase alignment with respect to the meshing of each gear, there is known one provided with a confirmation window for confirming the meshing state or the like at the time of assembly work (see, for example, Patent Document 1). ).

JP 2014-095327 A

  However, such a gear housing disclosed in the prior art document is a confirmation window for confirming the meshing state of the gears during assembly work, for example, during maintenance, etc. It was not a confirmation of individual deterioration.

  In particular, in the meshing relationship between the gear teeth of the driving gear and the gear teeth of the driven gear with reference to the power transmission path, the tooth surface of the driven gear that receives rotational stress (load) by the driving gear is the driving gear. It is easier to deteriorate than the tooth surface.

  Therefore, as in Patent Document 1, in the confirmation window for confirming the phase alignment with respect to the meshing between the gears during the assembly work, such deterioration of the tooth surface of the driven gear can be properly confirmed. There wasn't.

  In order to solve the above-described problems, an object of the technology of the present disclosure is to provide a gear housing capable of confirming deterioration of a tooth surface after use, which is different from an assembling operation.

  In order to achieve the above-described object, the technology of the present disclosure is a gear housing that houses one drive-side gear and one or more driven-side gears that are rotated directly or indirectly by using the drive-side gear as a drive source. In which a hole for confirming at least one tooth surface of the driven gear from the upstream side in the rotational direction of the driven gear is provided.

  The hole is preferably provided on the normal line of the peripheral surface of the driven gear.

  The hole is preferably provided on a virtual line orthogonal to the tooth surface of the driven gear.

  The hole is provided on an imaginary line that connects the tooth surface bottom of the gear tooth located downstream in the rotation direction of the driven gear and the peripheral end surface of the gear tooth adjacent to the gear tooth on the upstream side in the rotation direction. Is desirable.

  Further, it is desirable that the hole is provided at a position where no other gear including at least the driving side gear exists on an extension line of the normal line that goes downstream in the rotation direction of the driven side gear.

  The hole is preferably provided at a position where no other gear including at least the driving gear exists between the hole and the tooth surface.

  Moreover, it is desirable to provide a hole for confirming the tooth surface of the drive side gear from the downstream side in the rotation direction of the drive side gear.

  According to the technique of the present disclosure, it is possible to confirm the deterioration of the tooth surface after use, which is different from the assembly work.

1 is a schematic front view of an internal combustion engine to which a gear housing according to an embodiment of the present invention is applied. It is a side view of the principal part of the internal combustion engine to which the gear housing which concerns on one Embodiment of this invention is applied. The operational relationship between the drive side and the driven side of the gear housed in the gear housing according to one embodiment of the present invention is shown, (A) is an explanatory diagram of the meshing state of the gear teeth, (B) is an explanatory diagram of the stress relationship, (C) is explanatory drawing of the deterioration example of a tooth surface. It is explanatory drawing which shows the positional relationship of a tooth surface and a hole. It is an external appearance perspective view of the flywheel housing as a gear housing.

  Hereinafter, based on an accompanying drawing, a gear housing concerning one embodiment of the present invention is explained. In addition, the same code | symbol is attached | subjected to the same components and those names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  1 and 2, reference numeral 1 denotes an internal combustion engine provided with a flywheel housing 10 as a gear housing. In FIG. 1, the illustration of the flywheel housing 10 is omitted. The internal combustion engine 1 is, for example, a so-called OHC engine that opens and closes intake and exhaust valves in an overhead camshaft (Over Head Camshaft) system.

  As shown in FIGS. 1 and 2, the internal combustion engine 1 includes an engine block 2, a cylinder head 4 provided above the engine block 2 via a gasket 3, a cylinder head cover 5 covering the cylinder head 4, and And an oil pan 6 provided below the engine block 2.

  The engine block 2 is provided with a crankshaft 7, and the cylinder head 4 is provided with a camshaft 8. Further, the internal combustion engine 1 is provided with a timing gear train (hereinafter simply referred to as “gear train”) 9 for transmitting the power of the crankshaft 7 to the camshaft 8. The flywheel housing 10 covers the entire outside of the gear train 9.

  The gear train 9 is rotatably interposed between a crank gear 11 as a driving side gear fixed to the crankshaft 7, a cam gear 12 as a driven side gear fixed to the camshaft 8, and the crank gear 11 and the cam gear 12. A plurality of idle gears 13 to 15.

  When assembling the gear train 9, first, the crank gear 11 is fixed to the crankshaft 7 and attached to the engine block 2. The cam gear 12 is fixed to the cam shaft 8 and attached to the cylinder head 4. Further, the first idle gear 13 and the second idle gear 14 are attached to the engine block 2 in the order of the power transmission path, and the third idle gear 15 is attached to the cylinder head 4 between the second idle gear 14 and the cam gear 12.

  The idle gears 13 to 15 are arranged in the order of the power transmission path from the crank gear 11 as the driving gear to the cam gear 12 as the driven gear, in the order of the first idle gear 13, the second idle gear 14, and the third idle gear 15. It is arranged. The engine block 2 pivotally supports the first idle gear 13 and the second idle gear 14, and the cylinder head 4 pivotally supports the third idle gear 15. In addition, each idle gear 13-15 has a function as a drive side gear with respect to the gear in which the gear located in the upstream of a power transmission path | route is located in the downstream of a power transmission path | route. The second idle gear 14 includes a large diameter gear 13A and a small diameter gear 13B on the same axis.

  As described above, each of the idle gears 13 to 15 has a function as a driving gear and a function as a driven gear in the order of the power transmission path.

  Specifically, the large-diameter gear 13A when the crank gear 11 is a driving side gear is a driven side gear. In addition, the small-diameter gear 13B and the second idle gear 14 that rotate integrally with the large-diameter gear 13A are the driven-side gear when the small-diameter gear 13B is used as the driving gear. Further, the second idle gear 14 and the third idle gear 15 are the driven gears when the second idle gear 14 is a drive side gear. Further, the third idle gear 15 and the cam gear 12 are cam gears 12 when the third idle gear 15 is a drive side gear.

  Therefore, in the following description, as shown in FIGS. 3 and 4, the drive side gear of each gear in such a power transmission path is referred to as a drive gear R, and the driven gear is referred to as a driven gear N.

  As shown in FIG. 3A, in the drive gear R, a tooth surface located on the downstream side in the drive rotation direction (see the thick arrow) among the gear teeth is defined as a drive side tooth surface RA. On the other hand, in the driven gear N, a tooth surface located on the upstream side in the driven rotation direction among the gear teeth is defined as a driven side tooth surface NA. Thereby, as schematically shown in FIG. 3B, the driving-side tooth surface RA abuts on the driven-side tooth surface NA, and the driven gear N is rotated by applying the rotational load F.

  At this time, each tooth surface RA, NA is not a flat surface (flat surface) because the tooth surface shape is not a flat surface, and the rotational load F is applied while changing the contact position in line contact. It becomes. Thereby, as shown in FIG. 3 (C), pitching P may occur particularly as a result of deterioration such as scratches and chips on the driven tooth surface NA on the side receiving the rotational load F.

  And if such a pitching P is left as it is, there is a possibility that it will become larger, and there is a possibility that it will adversely affect the meshing of the gear teeth.

  As an example, the relationship between the rotational load F and the amount of collapse of the coating layer will be described. The surface of the coating layer has unevenness (swells) although it is minute compared to the layer thickness. That is, the layer thickness of the coating layer is not uniform. Therefore, when the rotational load F is low, the coating layer of the driven side tooth surface NA and the driving side tooth surface RA are only in partial contact.

  Although depending on conditions such as the type of coating material and the layer thickness, for example, when the rotational load F is 0 to 15 kgf, the change in the amount of crushing with respect to the rotational load F increases. This is because the unevenness is crushed. When the rotational load F is in the vicinity of 15 kgf, the unevenness is leveled and the coating layer and the driving side tooth surface RA come into full contact. Therefore, when the rotational load F is 15 kgf to 35 kgf, the change in the amount of crushing is small. On the other hand, when the rotational load F exceeds 35 kgf, the change in the amount of crushing becomes large. This is because the compression limit of the coating layer is exceeded.

  From the above, in order to obtain a more uniform layer thickness, it is desirable to set the rotational load F to 15 kgf or more. In consideration of the compression limit, the rotational load F is preferably set to 35 kgf or less.

  Therefore, the torque for rotating the cam gear 12 is preferably set to a magnitude such that the rotational load F on the coating layer is in the range of 15 kgf to 35 kgf. Thereby, generation | occurrence | production of a beep can be prevented, for example.

  However, even when such a rotational load F is set appropriately, when a power transmission balance such as the gear diameter of each gear, a body vibration that occurs when the vehicle travels, a resonance associated with engine vibration, or the like occurs. There is a risk that the coating layer may be peeled off unexpectedly.

  For this reason, for example, as shown in FIG. 2, it is possible to easily confirm whether or not the pitching P has occurred on the driven side tooth surface NA of the driven gear N at appropriate timings such as periodic inspection, maintenance, and vehicle inspection. In addition, holes 10A to 10D for direct visual recognition or confirmation using a fiberscope or the like are formed at appropriate positions of the flywheel housing 10.

  These holes 10A to 10D are, for example, on the normal line to the peripheral surface of the gear teeth perpendicular to the line segment extending in the radial direction from the rotation center as shown in FIG. 1, and can be confirmed from the upstream side in the rotational direction of the driven gear N. It is formed in the position. In FIG. 1, the holes 10 </ b> A to 10 </ b> D are replaced with lines of sight and are denoted by reference numerals.

  As described above, in the flywheel housing 10 that houses one drive gear R and one or more driven gears N that are rotated directly or indirectly by using the drive gear R as a drive source, at least one driven gear N is provided. By providing the holes 10A to 10D for confirming the driven-side tooth surface NA from the upstream side in the rotational direction of the driven gear N, the pitching P is generated in the driven-side tooth surface NA after use different from the assembling work. It is possible to easily confirm deterioration such as absence.

  At this time, the holes 10A to 10D are provided at positions where other driven gears N (the respective gears 12 to 15) including at least the drive gear R are not present on the extended line of the normal line toward the downstream side in the rotational direction of the driven gear N. ing. Thus, when the driven side tooth surface NR of the driven gear N on the near side is confirmed, there is no other driven gear N on the extended line of the normal line, so that the object to be confirmed is not obstructed by the other driven gear N. The driven tooth surface NA can be easily confirmed.

  Moreover, although the holes 10A to 10D have been described in the example provided on the normal line of the peripheral surface of the driven gear N (see the line segment (1) indicated by a two-dot chain line in FIG. 4) as replaced by the line of sight in FIG. However, the present invention is not limited to this.

  For example, the holes 10 </ b> A to 10 </ b> D may be provided on a virtual line orthogonal to the normal line of the driven side tooth surface NA of the driven gear N (see a line segment (2) indicated by a broken line in FIG. 4). Further, the holes 10A to 10D are on a virtual line connecting the tooth surface bottom of the gear tooth located downstream in the rotational direction of the driven gear N and the peripheral end surface of the gear tooth adjacent to the gear tooth upstream in the rotational direction (see FIG. 4 may be provided on a line segment (3) indicated by a one-dot chain line). As a result, the driven-side tooth surface NA can be easily confirmed without being obstructed by the gear teeth located on the upstream side of the driven-side tooth surface NA.

  Therefore, the holes 10A to 10D are provided at positions where other driven gears N (the gears 12 to 15) including at least the drive gear R do not exist between the holes 10A to 10D and the driven side tooth surface NA. Thereby, it is possible to prevent the line of sight from being blocked by another driven gear N.

  In addition, you may provide the hole for confirming the drive side tooth surface RA of the drive gear R from the rotation direction downstream of the drive gear R. Thereby, it is possible to confirm whether or not the pitching P has occurred on the drive side tooth surface RA of the drive gear (drive side gear) R. Note that the drive gear R here includes the crank gear 11 and the small-diameter gear 13B, but also includes the case where the idle gears 13 to 15 are functionally driving gears.

  FIG. 5 shows an example of a flywheel housing 10 as a gear housing. The flywheel housing 10 is, for example, an integrally molded product of casting. The flywheel housing 10 has a center hole through which the rear end portion of the crankshaft 7 is inserted at the center near the lower side of the front surface when the connection side to the internal combustion engine 1 is the front and the connection side to the clutch case (not shown) is the rear. 21 is formed. On the front surface of the flywheel housing 10, a reinforcing rib 22 formed in an annular shape surrounding the opening edge of the center hole 21, a fastening rib 23 formed in a wall shape so as to surround the outside of the reinforcing rib 22, and Are integrally formed. Bolt holes 24 for fixing the flywheel housing 10 to the rear surface portion of the internal combustion engine 1 through a plurality of bolts (not shown) are formed at a plurality of appropriate locations on the fastening ribs 23.

  As an example, the above-described hole 10 </ b> A is formed on the peripheral surface of the flywheel housing 10. For example, a fiberscope S can be inserted into the hole 10A, and the above-described large-diameter gear 13A is used as the driven gear N, so that the pitching P is not generated on the driven side tooth surface NA from the upstream side in the rotation direction. Confirmation can be made.

  Although the gear housing has been described as the flywheel housing 10 in the above embodiment, the present invention can be applied to all gear configurations in which at least the driving side gear and the driven side gear are covered with a single housing (case).

  As described above, the gear housing of the present invention is not limited to the above-described embodiment, and various technical changes can be made to the technical scope described in the claims within the scope of the invention. Included.

  In the above description, when there are descriptions such as “perpendicular”, “parallel”, and “plane”, these descriptions are not strict meanings. In other words, “vertical”, “parallel”, and “plane” allow tolerances and errors in design, manufacturing, etc., and mean “substantially vertical”, “substantially parallel”, and “substantially plane”. . Here, the tolerance and error mean a level within a range not departing from the configuration, operation, and effect of the present invention. Moreover, the value (numerical value) of the rotational load F described above is an example for convenience of explanation, and does not limit the present invention.

  As described above, the gear housing according to the present invention has an effect that it is possible to confirm deterioration of the tooth surface after use, which is different from the assembling work, and a plurality of gears including one drive side gear. It is useful for all gear housings that contain

10 Flywheel housing (gear housing)
10A-10D Hole R Drive gear (drive side gear)
RA Drive side tooth surface N Driven gear (driven gear)
NA Driven tooth surface (tooth surface)

Claims (7)

In a gear housing that houses one driving side gear and one or more driven side gears that rotate by receiving power directly or indirectly using the driving side gear as a driving source,
A hole for confirming the tooth surface of at least one driven gear from the upstream side in the rotational direction of the driven gear is provided.
A gear housing characterized by that. The hole is provided on the normal line of the peripheral surface of the driven gear,
The gear housing according to claim 1. The hole is provided on a virtual line orthogonal to the tooth surface of the driven gear,
The gear housing according to claim 1. The hole is provided on an imaginary line connecting a tooth surface bottom of a gear tooth located on the downstream side in the rotation direction of the driven gear and a peripheral end surface of the gear tooth adjacent to the gear tooth on the upstream side in the rotation direction.
The gear housing according to claim 1. The hole is provided at a position where no other gear including at least the drive side gear exists on an extension of the normal line toward the downstream side in the rotation direction of the driven side gear.
The gear housing according to claim 2. Between the hole and the tooth surface, provided at a position where no other gear including at least the drive side gear exists,
The gear housing according to any one of claims 2 to 5, wherein the gear housing is provided. A hole for confirming the tooth surface of the drive side gear from the downstream side in the rotation direction of the drive side gear is provided.
The gear housing according to any one of claims 1 to 6, wherein the gear housing is provided.

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