EP3201493A1 - Gear tooth crowning arrangement - Google Patents
Gear tooth crowning arrangementInfo
- Publication number
- EP3201493A1 EP3201493A1 EP15846508.8A EP15846508A EP3201493A1 EP 3201493 A1 EP3201493 A1 EP 3201493A1 EP 15846508 A EP15846508 A EP 15846508A EP 3201493 A1 EP3201493 A1 EP 3201493A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- lead
- gear
- parallel axis
- crown
- gears
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/02—Toothed gearings for conveying rotary motion without gears having orbital motion
- F16H1/04—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members
- F16H1/06—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes
- F16H1/08—Toothed gearings for conveying rotary motion without gears having orbital motion involving only two intermeshing members with parallel axes the members having helical, herringbone, or like teeth
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/08—Profiling
- F16H55/0886—Profiling with corrections along the width, e.g. flank width crowning for better load distribution
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H1/00—Toothed gearings for conveying rotary motion
- F16H1/28—Toothed gearings for conveying rotary motion with gears having orbital motion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
- F16H55/02—Toothed members; Worms
- F16H55/08—Profiling
- F16H2055/0893—Profiling for parallel shaft arrangement of toothed members
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H48/00—Differential gearings
- F16H48/20—Arrangements for suppressing or influencing the differential action, e.g. locking devices
- F16H48/28—Arrangements for suppressing or influencing the differential action, e.g. locking devices using self-locking gears or self-braking gears
- F16H48/285—Arrangements for suppressing or influencing the differential action, e.g. locking devices using self-locking gears or self-braking gears with self-braking intermeshing gears having parallel axes and having worms or helical teeth
Definitions
- the present disclosure relates generally to parallel-axis gears and more specifically, to a gear crowning arrangement.
- Gear trains that require torque sharing among multiple pinions may be found in the automotive industry such as in differentials and transmissions.
- Limited-slip differentials which use parallel-axis gearing rely on gear meshing events, and the friction thereof, to create the desired friction and torque bias.
- Gear alignment however is loosely controlled by the fit and clearance involved between the housing and gears. These misalignments, when combined with the high torque loads, can cause less than optimal gear meshing events. Historically, the fluctuation within these meshing events can cause undesirable noise.
- a parallel axis gear configuration constructed in accordance to one example of the present disclosure can include a first gear having a first gear tooth that includes a lead crowning across a face width thereof.
- the lead crowning can include (i) a first lead crown defined from a centeriine to a transition point and (ii) a second lead crown defined from the transition point to a first end point.
- the lead crowning can include a drop-off magnitude that is greater at the second lead crown than the first lead crown.
- the parallel axis gear configuration can further include a second gear that is in meshed relationship with the first gear.
- the first and second gears can be helical gears.
- the parallel axis gear configuration can further include a parallel axis differential that houses the first and second gears.
- the first gear can include a chemical vapor deposit coating thereon.
- the chemical vapor deposit can be BALI NIT ® C Star coating.
- a parallel axis gear configuration constructed in accordance to additional features of the present disclosure can include a first gear having a first gear tooth that includes a lead crowning across a face width thereof.
- the lead crowning can include (i) a first lead crown defined from a centerline to a transition point and (ii) a second lead crown defined from the transition point to a first end point.
- the first and second lead crowns can have distinct magnitudes across the face width.
- the second lead crown can include a drop-off magnitude that is greater at the second lead crown than the first lead crown.
- the first lead crown is zero.
- the parallel axis gear configuration can further include a second gear that is in meshed relationship with the first gear.
- the first and second gears can be helical gears.
- the parallel axis gear configuration can additionally include a parallel axis differential that houses the first and second gears.
- the first gear can include a chemical vapor deposit coating thereon.
- the chemical vapor deposit can be BALI NIT ® C Star coating.
- a parallel axis gear configuration constructed in accordance to additional features of the present disclosure can include a first gear and a second gear received in a housing in a meshed relationship.
- the first gear can include a first gear tooth that includes a first gear tooth lead crowning across a face width thereof.
- the first gear tooth lead crowning can include (i) a first lead crown defined from a centerline to a transition point and (ii) a second lead crown defined from the transition point to a first end point.
- the first gear tooth lead crowning includes a drop-off magnitude that is greater at the second lead crown than the first lead crown.
- the second gear can have a second gear tooth that includes a second gear tooth lead crowning across a face width thereof.
- the second gear tooth lead crowning can include (i) a first lead crown defined from a centerline to a transition point and (ii) a second lead crown defined from the transition point to a first end point.
- the second gear tooth lead crowning includes a drop-off magnitude that is greater at the second lead crown than the first lead crown.
- the second lead crowns of the respective first and second gear tooth lead crowns align with each other providing load intensities that inhibit micro-welding between the gears and the housing.
- the parallel axis differential can house the first and second gears.
- the first and second gears can both include a chemical vapor deposit coating thereon.
- the chemical vapor deposit can be BALINIT ® C Star coating.
- the first and second gears can be helical gears.
- the first lead crown of at least one of the first and second gear tooth lead crowning is non-zero.
- FIG. 1 is an exploded view of a parallel axis differential that can incorporate pinion gears according to one example of the present disclosure
- FIG. 2 is a perspective view of a pinion gear according to one example of prior art
- FIG. 3 is a side view of the pinion gear of FIG. 2;
- FIG. 4 is an exploded view of a first and second pinion gear and a first and second side gear used in the parallel axis differential of FIG. 1 ;
- FIG. 5 is a side view of an exemplary meshing event for corresponding pinion gears according to one example of prior art
- FIG. 6 is a side view of a pair of meshing pinion gears having areas of scuffing and deformation according to one example of prior art.
- FIG. 7 is a lead inspection profile of the pinion gear of FIG. 2;
- FIG. 8 is a lead inspection profile of a pinion gear having lead crowning constructed in accordance to one example of the present disclosure
- FIG. 9 is a lead inspection profile of a pinion gear having lead crowning constructed in accordance to a second example of the present disclosure.
- FIG. 10 is a lead inspection profile of a pinion gear having lead crowning constructed in accordance to a third example of the present disclosure
- FIG. 1 1 is a lead inspection profile of the pinion gear shown in FIG. 9 identifying additional features according to the present disclosure
- FIG. 12 is a lead inspection profile of a the pinion gear of FIG. 11 and identifying a crowning tolerance band according to one example of the present disclosure
- FIG. 13 is a load intensity distribution of a pair of mating pinion gears according to prior art.
- FIG. 14 is a load intensity distribution of a pair of mating pinion gears constructed in accordance to one example of the present disclosure
- the parallel axis differential 10 can include one or more side gears 12, a plurality of pinion gears 14, a differential case 20, a first cover 22, a second cover 24 and a plurality of fasteners 28.
- the pinion gears 14 are helical pinion gears.
- a gear train 30 can comprise one or more side gears 12 and a plurality of pinion gears 14. During operation, the plurality of pinion gears 14 may engage the two side gears 12.
- the side gears 12 may transmit torque from the respective pinion gears 14 to an output such as axle shafts (not shown).
- Each side gear 12 may have an axis of rotation and an inner axially aligned opening 34 through which an axle shaft may connect to the side gear 12 via a splined interconnection.
- Both side gears 12 may comprise heiicai teeth 36 configured to rotatably mesh with corresponding heiicai teeth 40 disposed on the pinion gears 14.
- the pinion gear 14 can include an axial lead 42.
- the pinion gear 14 can include a first zone 44, a second zone 46 and a third zone 48.
- the second zone 46 can be centrally located on the pinion gear 14.
- the first and third zones 44 and 48 can be located at opposite ends of the pinion gear 14.
- the pinion gear 14 includes crowning in the lengthwise direction.
- the average crowning amount is referred to as Cp.
- the average crown is defined within the second zone 46.
- the first zone 44 and the third zone 48 on a pinion gear constructed according to the present disclosure will have a drop-off defined in length and magnitude.
- FIGS. 5 and 6 illustrate a pair of meshed pinion gears 14 according to prior art.
- the respective teeth 40 of the meshed pinion gears 14 engage at an interface area 50.
- the pinion gears 14 may develop scuffing 52 and/or plastic deformation 54 thereon during use.
- the present disclosure is directed toward a gear tooth crowning arrangement on the pinion gears 40.
- the gear tooth crowning arrangement disclosed herein permits more consistent gear meshing events which reduce the noise, vibration and handling (NVH) level of the parallel axis differential 10.
- the present disclosure can be shown to inhibit end-loading of the gear train 30 and compensate for any misalignments.
- FiG. 7 a baseline lead profile according to one example of prior art is shown and generally identified at reference 70.
- a face width 72 is horizontal or linear along the lead profile 70. No crowning is provided on the lead profile 70.
- FIG. 8 illustrates a lead profile 80 having a face width 82 that includes a first lead crown 84 and a second lead crown 86 in accordance to the present teachings.
- the first lead crown 84 is defined from a centerline 88 to a transition point 90.
- the second lead crown 86 is defined from the transition point 90 to a first end point 92.
- the first lead crown 84 can be zero.
- the first lead crown 84 can have no crowning.
- the second lead crown 86 can have a drop-off.
- the drop-off can correspond to an area of reduced gear teeth contact with a mating gear (having a similar lead crown drop-off).
- the drop-off can be located in one or both of the first and third zones 44, 48 (FIG. 3).
- the lead profile 80 can be similar between the centerline 88 and a second end point 94. In such a configuration, while only one end may be meshed with a corresponding pinion gear, having a similar lead crown on both ends of the pinion gear can help with assembly as the gear may be installed into the differential case 20 with either end first.
- FIG. 9 illustrates a lead profile 100 having a face width 102 that includes a first lead crown 104 and a second lead crown 106.
- the first lead crown 104 is defined from a centerline 108 to a transition point 110.
- the second lead crown 106 is defined from the transition point 110 to a first end point 112.
- the first lead crown 104 can be non-zero (as compared with the first lead crown 84 shown in FIG. 8).
- the lead profile 100 can be similar between the centerline 108 and a second end point 114. in such a configuration, while only one end may be meshed with a corresponding pinion gear, having a similar lead crown on both ends of the pinion gear can help with assembly as the gear may be installed into the differential case 20 with either end first.
- FIG. 10 illustrates a lead profile 120 having a face width 122 that includes a first lead crown 124.
- the first lead crown 124 is defined from a centerline 128 to a first end point 132.
- the first lead crown 124 can be nonzero (as compared with the first lead crown 84 shown in FIG. 8).
- the first lead crown 124 can be continuous from the centerline 128 to the end point 132.
- the first lead crown 124 can be similar to the first lead crown 104 described in FIG. 9 however, the first lead crown 124 can continue to the first end point 132 without a defined transition.
- the lead profile 120 can be similar between the centerline 128 and a second end point 134. In such a configuration, while only one end may be meshed with a corresponding pinion gear, having a similar lead crown on both ends of the pinion gear can help with assembly as the gear may be installed into the differential case 20 with either end first. It is appreciated however that while the lead profile 120 is shown having both ends of the pinion crowned (such as to assist with assembly), the pinion gear 14 may be constructed as having only one end with a lead crown.
- FIG. 11 shows features of the lead profile 80 (FIG. 8), the lead profile 100 (FIG. 9) and the lead profile 120 (FIG. 10) together.
- a drop-off magnitude M is identified between the first lead crown 124 and the second lead crown 106.
- the drop-off magnitude M can be greater than a distance 150 between a foundation line 152 and a centerline 108, 128.
- the drop-off magnitude M can be a multiple of 1.5 greater than a distance 150.
- Other configurations are contemplated.
- a drop-off distance L is identified between the transition points 90, 110 and the first end points 92, 112.
- the drop-off distance L can be determined based on a given application.
- FIG. 12 illustrates an exemplary crowning tolerance band 170 having an upper tolerance 172 and a lower tolerance 174.
- the crowning tolerance band 170 identifies an area that the lead profile can occupy while still providing the reduced NVH levels in a given gear train.
- FIG. 13 illustrates a load intensity distribution 200 for a pinion gear disposed in a parallel axis differential according to prior art.
- an active face width shows increased load intensities 202 and 204 in meshed areas consistent with a meshed interface area 50 (FIGS. 5 and 6).
- the increased load intensities 202 and 204 produce unfavorable NVH.
- FIG. 14 illustrates a load intensity distribution 210 for a pinion gear having a lead crowning according to one of the examples of the present disclosure and disposed in a parallel axis differential.
- an active face width shows reduced load intensities 212 and 214 in meshed areas consistent with a meshed interface area 50.
- the reduced load intensities 212 and 214 provide improved NVH characteristics.
- the reduced load intensities avoids micro-welds and subsequent breaking of those micro-welds causing NVH chatter.
- the micro-welds can occur in prior art examples between the pinion teeth 40 and the housing 20.
- a chemical vapor deposit coating may be additionally or alternatively applied to the pinion gears 14 that can be shown to provide improved NVH qualities.
- One such product is a chemical vapor deposit coating marketed by Oerlikon Balzers of Liechtenstein.
- BALINIT ® C Star coating marketed by Oeriikon Baizers.
- the chemical vapor deposit coating can reduce friction and/or pressure between the pinion gears 14 and the housing. In this regard, the coating can reduce the propensity of the micro-welds from forming between the pinion gears 14 and the housing 20 and the resulting stick-slip action that would otherwise cause noise.
- high pressure, lack of sufficient lubricant, and similarity of material properties such as hardness, alloy content, and surface finish are characteristics that can encourage micro-welds.
- the chemical vapor deposit coating, such as identified above separates and protects the substrate materials from contacting each other in this operating scenario. Preventing such micro-welding and adhesive wear has been shown to also improve the NVH performance of the differential.
- tip relief may be added in the involute profile direction (measuring from root to tip). This further helps improve the load intensity plot in FIG. 14. Such tip relief may be produced with specially designed hob cutters.
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Retarders (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201462058785P | 2014-10-02 | 2014-10-02 | |
US201462096009P | 2014-12-23 | 2014-12-23 | |
PCT/US2015/049411 WO2016053590A1 (en) | 2014-10-02 | 2015-09-10 | Gear tooth crowning arrangement |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3201493A1 true EP3201493A1 (en) | 2017-08-09 |
EP3201493A4 EP3201493A4 (en) | 2018-10-31 |
Family
ID=59254048
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP15846508.8A Withdrawn EP3201493A4 (en) | 2014-10-02 | 2015-09-10 | Gear tooth crowning arrangement |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP3201493A4 (en) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB741376A (en) * | 1953-02-05 | 1955-11-30 | Parsons & Marine Eng Turbine | Improvements in and relating to helical tooth gearing |
US3206997A (en) * | 1960-11-16 | 1965-09-21 | Gen Motors Corp | Gearing |
GB1460934A (en) * | 1974-09-13 | 1977-01-06 | British Leyland Uk Ltd | Gear teeth |
US6682456B2 (en) * | 2001-12-10 | 2004-01-27 | Axicon Technologies, Inc. | Multi-mesh gear system |
JP5857822B2 (en) * | 2012-03-19 | 2016-02-10 | トヨタ自動車株式会社 | Gear mechanism and manufacturing method thereof |
-
2015
- 2015-09-10 EP EP15846508.8A patent/EP3201493A4/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
EP3201493A4 (en) | 2018-10-31 |
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