JP2020041567A - gear - Google Patents

Abstract

To provide a gear that can suppress positional deviation while having a vibration control function.SOLUTION: A gear G comprises a first gear 1 and a second gear 2. The first gear and the second gear each have a first tooth part 11 and a second tooth part 12 having the same module and the same number of teeth on an outer peripheral part, and are adjacent to each other in an axial direction. The first gear has a body part 6 located radially inward of the first tooth part, and an elastic member 7 connecting the first tooth part and the body part. The body part is fixed to the second gear so as not to be rotatable relatively, and the first tooth part is arranged so as to be rotatable relative to the second gear. The over-ball diameter of the first gear is larger than the over-ball diameter of the second gear.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to gears.

  Some gears have a vibration suppression function or a damper function in order to reduce rattle noise caused by rattling vibration. As one example, there is a structure in which a gear having outer peripheral teeth is divided into an outer portion and an inner portion in the radial direction, and the outer portion and the inner portion are connected by an elastic member such as rubber or a vibration damping member.

JP-A-61-32855 JP-A-2002-98221

  However, with this structure, when the driving force is transmitted by meshing with the mating gear, the elastic member is deformed and the phases of the outer portion and the inner portion are shifted. Therefore, this structure is not necessarily suitable for a gear device such as a timing gear train that needs to keep the phase shift below a certain level.

  Therefore, the present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a gear having a vibration suppression function and capable of suppressing a phase shift.

According to one aspect of the present disclosure,
A first gear and a second gear,
The first gear and the second gear have a first tooth portion and a second tooth portion having the same module and the same number of teeth on the outer peripheral portion, respectively, and are axially adjacent to each other,
The first gear has a main body located radially inward of the first tooth, and an elastic member connecting the first tooth and the main body,
The main body is fixed to the second gear so as not to rotate relatively,
The first tooth portion is disposed so as to be rotatable relative to the second gear,
A gear is provided, wherein an overball diameter of the first gear is larger than an overball diameter of the second gear.

  Preferably, the elastic member is formed in a ring shape extending all around and connects the tooth portion and the main body at all positions.

  According to the present disclosure, it is possible to provide a gear having a vibration suppression function and capable of suppressing a phase shift.

1 is a schematic vertical sectional view of a gear according to an embodiment of the present disclosure. It is a schematic diagram when a 1st tooth part and a 2nd tooth part are seen from the axial direction.

  Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the present disclosure is not limited to the following embodiments.

  FIG. 1 is a schematic longitudinal sectional view of a gear according to an embodiment of the present disclosure. The gear G includes a first gear 1 and a second gear 2, and a combination of these two gears 1 and 2 constitutes one gear G, that is, a gear assembly. C indicates a central axis of the gear G (referred to as a gear axis). Hereinafter, unless otherwise specified, the axial direction, the radial direction, and the circumferential direction refer to the axial direction, the radial direction, and the circumferential direction based on the gear axis C. For convenience, the right side in the figure is defined as the front in the axial direction, and the left side in the figure is defined as the rear in the axial direction.

  The gear G is configured as a spur gear having outer peripheral teeth, and is applied so as to mesh with a mating gear 20 indicated by a virtual line.

  The first gear 1 and the second gear 2 are arranged adjacent to each other in the axial direction, and the first gear 1 is arranged adjacent to and axially forward of the second gear 2.

  The 1st gear 1 and the 2nd gear 2 have the 1st tooth part 11 and the 2nd tooth part 12 in the outer peripheral part, respectively. The first tooth portion 11 and the second tooth portion 12 have the same module and the same number of teeth, and are arranged without a phase difference. The first teeth 11 and the second teeth 12 are formed as if the teeth of one gear were divided in the thickness direction. The first gear 11 and the second gear 12 are both meshed with the mating gear 20.

  The second gear 2 is generally integrally formed in a ring plate shape, and has a support portion 3 formed on an inner peripheral portion, and a connecting portion 4 connecting the second tooth portion 12 and the support portion 3. The connecting portion 4 is formed in a dish shape whose thickness (thickness in the axial direction) is smaller than that of the second tooth portion 12 and the supporting portion 3 by reducing the thickness of the front surface portion and the rear surface portion, thereby reducing the weight. I have. A support hole 5 to be fitted to the first gear 1 is provided in an inner peripheral portion of the support portion 3.

  The first gear 1 has a main body 6 located radially inward of the first teeth 11, and an elastic member 7 as a vibration damping member connecting the first teeth 11 and the main body 6. The elastic member 7 is formed of an elastic material such as rubber.

  The first tooth portion 11 integrally has a dish-shaped outer peripheral side connecting portion 8 similar to the outer peripheral side portion of the connecting portion 4. The main body 6 also integrally has a dish-shaped inner peripheral side connecting portion 9 similar to the inner peripheral side portion of the connecting portion 4. The elastic member 7 is interposed between the outer peripheral side connecting portion 8 and the inner peripheral side connecting portion 9 and is fixed to both, thereby connecting the both. The elastic member 7, the outer peripheral side connecting part 8 and the inner peripheral side connecting part 9 have the same thickness. The elastic member 7 is formed in a ring shape extending all around the circumference, and connects the outer circumference side connection portion 8 and the inner circumference side connection portion 9 at all circumference positions. The total radial length of the outer connecting portion 8, the elastic member 7, and the inner connecting portion 9 is equal to the radial length of the connecting portion 4.

  The first tooth portion 11 integrally has a support portion 10 in the form of a cylindrical boss on the radially inner side of the inner peripheral side connection portion 9. A support hole 10 </ b> A that is fitted to a shaft (not shown) is provided in an inner peripheral portion of the support portion 10. A shaft portion 12A is provided on the outer peripheral portion of the support portion 10 so that the support hole 5 of the second gear 2 is fitted and fixed by a method such as shrink fitting. A contact surface 13 extending radially outward is formed at the front end of the shaft portion 12A. When the front surface of the support portion 3 of the second gear 2 abuts on the abutment surface 13, the second gear 2 is axially positioned with respect to the first gear 1.

  In the state where the second gear 2 is fixed to the first gear 1 in this manner, an axial direction between the first tooth 11 of the first gear 1 and the second tooth 12 of the second gear 2 is provided. A slight gap 14 is formed. Therefore, while the main body 6 of the first gear 1 is fixed to the second gear 2 so as to be relatively non-rotatable, the first teeth 11 of the first gear 1 are deformed by the elastic member 7 so that the second gear 2 Are disposed so as to be rotatable relative to.

  The gear G according to the present embodiment is also characterized in that the overball diameter of the first gear 1 is larger than the overball diameter of the second gear 2. Here, the over ball diameter (OBD) is, as is known, when a ball or pin is inserted into the tooth grooves at both ends of the gear and the outer diameter of these two balls or pins is measured. Means the outside diameter.

  FIG. 2 schematically and exaggeratedly shows the first tooth portion 11 and the second tooth portion 12 of FIG. 1 when viewed from the rear in the axial direction. The broken line indicates the first tooth portion 11, the solid line indicates the second tooth portion 12, and the dashed line indicates the tooth portion of the mating gear 20.

  B1 indicates a ball inserted into the tooth space of the first tooth portion 11 (it may be a pin; the same applies hereinafter), and B2 indicates a ball inserted into the tooth space of the second tooth portion 12. As can be seen from this figure, the overball diameter OBD1 of the first gear 1 defined by the ball B1 is larger than the overball diameter OBD2 of the second gear 2 defined by the ball B2.

  Further, as shown in the illustrated example, the height positions of the tip 31 and the tooth bottom 41 of the first tooth portion 11 can be equal to the height positions of the tooth tip 32 and the tooth bottom 42 of the second tooth portion 12. . Further, the tooth thickness t1 of the first tooth portion 11 at the same height position can be larger than the tooth thickness t2 of the second tooth portion 12.

  As a result, the backlash (or clearance) R1 between the tooth of the first tooth portion 11 and the tooth of the mating gear 20 is larger than the backlash R2 between the tooth of the second tooth portion 12 and the tooth of the mating gear 20. Become smaller.

  The overball diameter OBD2 of the second gear 2 is always determined by considering the overball diameter variation at the time of manufacturing the gear and the assembling variation such as shrink fitting of the second gear 2. It is set to be larger.

  In the state after the gear is assembled, as shown in the figure, the tooth thickness center C1 which bisects the tooth thickness t1 of the first tooth portion 11 in the circumferential direction is equal to the tooth thickness t2 of the second tooth portion 12 in the circumferential direction. It is located at the same circumferential position as the tooth thickness center C2 to be divided. Similarly, the tooth groove center C11 that bisects the tooth groove of the first tooth portion 11 in the circumferential direction is the same circumferential direction as the tooth groove center C12 that bisects the tooth groove of the second tooth portion 12 in the circumferential direction. Position. In such a position, the first tooth portion 11 is assumed to have no phase shift with respect to the second tooth portion 12 or to be at the same reference phase position.

  Next, the operation and effect of the present embodiment will be described.

  For example, it is assumed that the gear G is a non-drive-side gear, the partner gear 20 is a drive-side gear, and the gear G is driven by the partner gear 20. In this case, the teeth of the mating gear 20 come into contact with the teeth of the first teeth 11 before the teeth of the second teeth 12 and press the teeth of the first teeth 11. Then, the elastic member 7 is elastically deformed, and the first tooth portion 11 rotates relative to the second tooth portion 12, causing a slight phase shift. At this time, the rattling vibration generated by the contact between the tooth of the mating gear 20 and the tooth of the first tooth portion 11 is attenuated by the elastic member 7 before reaching the main body portion 6, thereby reducing the generation of rattle noise. Can be suppressed.

  When the teeth of the mating gear 20 further press the teeth of the first teeth 11, the teeth of the mating gear 20 also contact the teeth of the second tooth 12. As a result, the driving torque from the teeth of the mating gear 20 is transmitted to the gear G through both the teeth of the first teeth 11 and the teeth of the second teeth 12. At this point, the first teeth 11 stop rotating relative to the second teeth 12. Even if the driving torque increases, it can be reliably transmitted to the gear G by the two teeth 11 and 12.

  At this time, the teeth of the mating gear 20 come into contact with the first teeth 11 and come into contact with the second teeth 12 after the elastic member 7 is elastically deformed. This can attenuate the rattling vibrations more than usual, and can suppress the generation of rattle noise.

  As described above, by making the over-ball diameter OBD1 of the first gear 1 larger than the over-ball diameter OBD2 of the second gear 2, the teeth of the mating gear 20 at the initial stage of torque transmission are made smaller than the teeth of the second tooth portion 12. Before, it can be brought into contact with the teeth of the first teeth 11. Thereby, the rattling vibration is attenuated by the elastic member 7, and the generation of rattle noise can be suppressed.

  In addition, since the teeth of the mating gear 20 contact the teeth of the second tooth portion 12 after contacting the first teeth, the rattling vibrations of the teeth of the mating gear 20 and the teeth of the second tooth portion 12 are attenuated. Thus, generation of rattle noise can be suppressed.

  Further, when the teeth of the mating gear 20 come into contact with the teeth of the second tooth portion 12, the relative rotation of the first tooth portion 11 with respect to the second tooth portion 12, that is, the phase shift can be stopped. Therefore, it is possible to provide the gear G that minimizes the phase shift and has the vibration damping function and can also suppress the phase shift.

  Since the gear G can minimize the phase shift of the first gear 1 with respect to the second gear 2, it is suitable for a gear device such as a timing gear train in which the phase shift needs to be suppressed to a certain level or less. For example, in the case of a gear mechanism that transmits the driving force of a crankshaft of an internal combustion engine to a camshaft, if the phase shift of a gear with a vibration damping function used in the gear mechanism is large, the phase of the camshaft with respect to the crankshaft becomes unacceptable. There is a risk that the displacement will be large. However, the gear G of the present embodiment has a minimum phase shift, and is thus very suitable as a gear with a vibration damping function used in the gear mechanism.

  Here, if the backlash between the teeth of the second tooth portion 12 and the teeth of the mating gear 20 is made equal to the backlash between the teeth of the normal gear having no vibration damping function and the teeth of the mating gear. In this case, the amount of phase shift is negligible as in the case where a normal gear is used, which is more suitable for a gear device that needs to suppress the phase shift.

  Although the case where the gear G is the non-drive-side gear has been described above, the same applies when the gear G is the drive-side gear.

  As described above, the embodiments of the present disclosure have been described in detail. However, the present disclosure may have other embodiments as follows.

  (1) For example, the elastic member 7 may be provided intermittently in the circumferential direction.

  (2) The first gear 1 and the second gear 2 may be fixed by a method other than shrink fitting, for example, by bolting.

  The embodiments of the present disclosure are not limited to the above-described embodiments, but include all modifications, applications, and equivalents included in the spirit of the present disclosure defined by the claims. Therefore, the present disclosure should not be construed as limiting, but can be applied to any other technology belonging to the scope of the idea of the present disclosure.

G Gear 1 First gear 2 Second gear 6 Body 7 Elastic member 11 First tooth 12 Second tooth OBD1, OBD2 Overball diameter

Claims (2)

A first gear and a second gear,
The first gear and the second gear have a first tooth portion and a second tooth portion having the same module and the same number of teeth on the outer peripheral portion, respectively, and are axially adjacent to each other,
The first gear has a main body located radially inward of the first tooth, and an elastic member connecting the first tooth and the main body,
The main body is fixed to the second gear so as not to rotate relatively,
The first tooth portion is disposed so as to be rotatable relative to the second gear,
The gear, wherein an overball diameter of the first gear is larger than an overball diameter of the second gear. The gear according to claim 1, wherein the elastic member is formed in a ring shape extending all around and connects the tooth portion and the body at all positions.

Images