GB2508978A - Differential gear with solenoid operated locking mechanism - Google Patents

Differential gear with solenoid operated locking mechanism Download PDF

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Publication number
GB2508978A
GB2508978A GB201319067A GB201319067A GB2508978A GB 2508978 A GB2508978 A GB 2508978A GB 201319067 A GB201319067 A GB 201319067A GB 201319067 A GB201319067 A GB 201319067A GB 2508978 A GB2508978 A GB 2508978A
Authority
GB
United Kingdom
Prior art keywords
gear
differential gear
locking element
axle shaft
locking
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Withdrawn
Application number
GB201319067A
Other versions
GB201319067D0 (en
Inventor
Ranganatha Rao Ayanur Sundaresha
Vishal Keerthi Kuntadka Rathnaraja
Ranjeet Vijayswamy
Arul Anand
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mercedes Benz Group AG
Original Assignee
Daimler AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Daimler AG filed Critical Daimler AG
Priority to GB201319067A priority Critical patent/GB2508978A/en
Publication of GB201319067D0 publication Critical patent/GB201319067D0/en
Publication of GB2508978A publication Critical patent/GB2508978A/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K17/00—Arrangement or mounting of transmissions in vehicles
    • B60K17/02—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of clutch
    • 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
    • F16H48/06—Differential gearings with gears having orbital motion
    • F16H48/08—Differential gearings with gears having orbital motion comprising bevel gears
    • 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
    • F16H48/24—Arrangements for suppressing or influencing the differential action, e.g. locking devices using positive clutches or brakes
    • 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
    • F16H48/30—Arrangements for suppressing or influencing the differential action, e.g. locking devices using externally-actuatable means
    • 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
    • F16H48/30—Arrangements for suppressing or influencing the differential action, e.g. locking devices using externally-actuatable means
    • F16H48/34—Arrangements for suppressing or influencing the differential action, e.g. locking devices using externally-actuatable means using electromagnetic or electric actuators
    • 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
    • F16H48/30—Arrangements for suppressing or influencing the differential action, e.g. locking devices using externally-actuatable means
    • F16H48/34—Arrangements for suppressing or influencing the differential action, e.g. locking devices using externally-actuatable means using electromagnetic or electric actuators
    • F16H2048/346—Arrangements for suppressing or influencing the differential action, e.g. locking devices using externally-actuatable means using electromagnetic or electric actuators using a linear motor

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Retarders (AREA)

Abstract

Differential gear 10 having housing 12, axle shaft 24 rotatable relative to housing 12, compensating gear 26, side gear 34 meshing with compensating gear 26 and connected to axle shaft 24, locking element 36 coaxial and partly within shaft 24 and movable between locking and release positions of differential 10, and solenoid for moving locking element 36. Lock 36 may have a first face with gear teeth (figure 2, 60, 62) facing a second face with gear teeth (figure 3, 64, 66) on axle shaft 24, which may mesh to lock. Bolt 30 may: be attached to housing 12, partly house lock 36, have compensating gear 26 rotatably mounted thereon, and have inner circumferential teeth 58 meshing with outer circumferential teeth (figure 2, 54) of lock 36. Axle 24 may penetrate solenoid 38. Solenoid 38 may move lock 36 from release to locking position, and spring 68 may reverse this.

Description

Intellectual Property Office Applicathin No. GB13190673 RTM Dac:30 April 2014 The following terms are registered trade marks and should he rcad as such wherever they occur in this document: "Curvic", which appears on multiple occasions on pages 5 and 6 of the application.
Inlelleclual Properly Office is an operaling name of the Pateni Office www.ipo.gov.uk Differential Gear for a Vehicle The invention relates to a differential gear for a vehicle, in particular a drive axle for a motor vehicle according to the preamble of patent claim 1.
In automobiles as well as other wheeled vehicles, differential gears are used to allow the driving road wheels to rotate at different speeds. This is advantageous when the vehicle turns, making the wheel that is travelling around the outside of turning curve roll farther and faster than the inside wheel. From the general prior art, it is known to use locking elements in such differential gears to lock the differential gears so that the road wheels cannot rotate at different speeds anymore regardless of which of the road wheels has more traction.
DE 38 08 402 Al shows a differential gear for a vehicle, the differential gear comprising at least one housing element in the form of a differential case, at least one axle shaft being rotatable in relation to the housing element and at least one compensating gear in the form of a differential pinion rotatably arranged in the housing element. The differential gear also comprises at least one side gear rotatably arranged in the housing element, the side gear meshing with the compensating gear and being connected to the axle shaft.
Thereby the axle shaft can be driven via the side gear and the compensating gear.
Furthermore, the differential gear comprises at least one locking element for locking the differential gear. The locking element is arranged coaxially in relation to the axle shaft.
The locking element is capable of being moved between at least one locking position and at least one release position. In the locking position the differential gear is locked so that road wheels of the vehicle cannot rotate at different speeds. In the release position the road wheels can rotate at different speeds since the differential gear is not locked.
Additionally, the differential gear comprises at least one solenoid for moving the locking element. Such a differential gear can also be found in DE 38 44 35 C2.
The differential gears known from the prior art have very high packaging space requirements.
It is therefore an object of the present invention to provide a differential gear for a vehicle which requires very little installation space only.
This object is solved by a differential gear having the features of patent claim 1.
Advantageous embodiments with expedient and non-trivial developments of the invention are indicated in the other patent claims.
In order to provide a differential gear of the kind indicated in the preamble of patent claim 1, which requires very little installation space, according to the present invention the locking element is arranged partly within the axle shaft. Thereby a lot of packaging space can be saved in comparison with conventional differential gears. Moreover, the axle shaft can be used as a guide for guiding the locking element during its movement between the locking position and the release position.
Furthermore, the installation space of the differential gear can be kept particularly low since at least one solenoid and, thus, electric actuation instead of a pneumatic or hydraulic actuation is used to move the locking element. Thus, the differential gear according to the present invention is very easy to maintain and operate. Furthermore, the number of parts of the differential gear can be kept particularly low because of using the solenoid and, thus, electric energy to move the locking element. By electrically operating or controlling the differential gear, a pneumatic as well as a hydraulic system can be avoided resulting in a very low weight of the differential gear.
Further advantages, features, and details of the invention derive from the following description of a preferred embodiment as well as from the drawing. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respective indicated combinations but also in any other combination or taken alone without leaving the scope of the invention.
The drawings show in: Fig. 1 A schematic sectional view of a differential gear for a vehicle, the differential gear comprising a locking element for locking the differential gear, wherein the locking element is arranged partly within an axle shaft of the differential gear; Fig. 2 A schematic perspective view of the locking element; and Fig. 3 A schematic perspective view of the axle shaft.
In the figures the same elements or elements having the same functions are indicated with the same reference signs.
Fig. 1 shows a differential gear 10 for a vehicle, in particular, a motor vehicle. The differential gear 10 comprises a housing element 12 which is also referred to as differential case. The differential gear 10 also comprises a driven gear element in the form of a ring gear 14 which is rigidly attached to the housing element 12. As can be seen from Fig. 1, the differential gear 10 is arranged at least partly in a housing 16 of the vehicle. The ring gear 14 meshes with a drive gear or a drive mechanism in the form of a drive bevel pinion 18. Thereby, the ring gear 14 and the housing element 12 can be driven via the drive mechanism by means of, for example, a combustion engine of the vehicle.
The housing element 12 is rotatably mounted on the housing 16 about a rotation axis by means of bearings 20. The differential gear 10 also comprises axle shafts 22, 24. Road wheels of the vehicle are attached to the axle shafts 22, 24 so that the road wheels can be driven via the axle shafts 22, 24. The axle shafts 22, 24 are rotatable in relation to the housing element 12. The axle shaft 22 and/or 24 rotate in relation to the housing element 12 if, for example, the differential gear 10 is unlocked and the vehicle turns. If the differential gear 10 is locked the axle shafts 22, 24 cannot rotate in relation to the housing element 12.
Furthermore, the differential gear 10 comprises compensating gears in the form of differential pinions 26 and 28. The pinions 26, 28 are rotatably arranged in the housing element 12. This means that the pinions 26, 28 are rotatably mounted on the housing element 12 about a rotation axis. For this purpose the differential gear 10 comprises a bolt which is referred to as spider 30. The spider 30 is formed in one piece and rigidly attached to the housing element 12 so that the spider 30 cannot move in relation to the housing element 12. The pinions 26, 28 are rotatably mounted on the spider 30 about a rotation axis respectively.
Additionally, the differential gear 10 comprises side gears 32, 34 rotatably arranged in the housing element 12. The side gear 32 is connected to the axle shaft 22, wherein the side gear 34 is connected to the axle shaft 24. Thereby, the axle shaft 22, 24 can be driven via the side gears 32, 34, the pinions 26, 28, the housing element 12, the ring gear 14 and bevel pinion 18. In other words, the power flow is from the drive bevel pinion 18 to the ring gear 14 to the differential case (housing element 12) to the spider 30 to the differential pinions 26 and 26 to the side gears 32 and 34 to the axle shafts 24 and 22. Thereby, the the differential gear 10 is designed to drive the road wheels while allowing them to rotate at different speeds when, for example, the vehicle turns. The road wheels and thus the axle shaft 22, 24 can rotate at different speeds when the differential gear 10 is in its unlocked state.
The differential gear 10 can be shifted into a locked state in which the axle shafts 22, 24 and, thus, the road wheels cannot rotate at different speeds. In order to shift the differential gear 10 between the locked state and the unlocked state, the differential gear comprises a locking element 36 which is also referred to as actuator. The locking element 36 is arranged coaxially in relation to the axle shaft 24 and capable of being moved between at least one locking position and at least one released position.
In the locking position of the locking element 36, the differential case (housing element 12) is locked rigidly to the axle shaft 24. In the released position of the locking element 36, the differential case is released or unlocked such that the differential case can be moved in relation to the axle shaft 24. Thus, in the locking position of the locking element 36 the differential gear 10 is locked so that the differential gear 10 is in its locked state. In the released position of the locking element 36, the differential gear 10 is released or unlocked so that differential gear 10 is in its unlocked state.
The differential gear 10 also comprises a solenoid 38 for moving the locking element 36 from its released position into its locking position. As shown in Fig. 1, the solenoid 38 is placed around the axle shaft 24.
As can be seen from Fig. 2, the locking element 36 has an actuator guide rod portion 40 and an actuator head portion 42 rigidly connected to the rod portion 40. As can be seen from Fig. 1, in the assembled state of the differential gear 10 the rod portion 40 is arranged partly within a receptacle in the form of a bore 44 of the axle shaft 24.
As shown in Fig. 1, the locking element 36 is also partly arranged within the spider 30. In the embodiment according to Fig. 1, the head portion 42 is arranged within the spider 30.
For this purpose the spider 30 has a centre portion 48 having a receptacle 50 in which the head portion 42 is arranged.
As can be seen from Fig. 2, the actuator head portion 42 has an outer circumferential lateral surface 52 with outer circumferential gear teeth in the form of an external spline 54. The spider 30 has an inner circumferential lateral surface 56 with inner circumferential gear teeth in the form of an internal spline 58. In the assembled state of the differential gear 10, the external spline 54 meshes with the internal spline 58 so that the spider 30 is connected to the differential locking element 36. In other words, the locking element 36 is constantly engaged with the spider 30. Thus, if the spider 30 rotates along with the housing element 12, the locking element 36 rotates along with the spider 30.
As can be seen from Fig. 2, the differential locking element 36 has a first face side 60 having first gear teeth 62 in the form of actuator curvic teeth. As can be seen from Fig. 3, the axle shaft 24 has a second face side 64 having second gear teeth 66 in the form of axle shaft curvic teeth. In the assembled state of the differential gear 10, the first face side 60 faces the second face side 64. The locking element 36 is translationally movable in relation to the axle shaft 24 along the rotation axis about which the axle shaft 24 can rotate. Thus, the actuator curvic teeth can be moved translationally in relation to the axle shaft curvic teeth.
In the locked state of the differential gear 10, this means in the locking position of the locking element 36, the actuator curvic teeth mesh with the axle shaft curvic teeth. Hence, the axle shaft 24 is connected to the spider 30 and via the spider 30 to the housing element 12 so that the axle shafts 22, 24 and, thus, the road wheels cannot rotate at different speeds.
In the unlocked state of the differential gear 10, this means the released position of the locking element 36, the actuator curvic teeth do not mesh with the axle shaft curvic teeth so that the locking element 36 is decoupled from the axle shalt 24. Thus, the axle shaft 24 is not rigidly connected to the spider 30 and the housing element 12 so that the axle shalt 22, 24 and, thus, the road wheels can rotate at different speeds, this means in relation to each other.
In order to move the locking element 36 from its released position into its locking position the solenoid 38 is actuated. If the solenoid 38 is activated it magnetizes the axle shaft 24 which in turn attracts the locking element 36 thus moving the locking element 36 into the locking position.
By moving from the released position into the locking position, a spring 68 (Fig. 1) which is also referred to as "actuator spring" is loaded, the spring 68 being arranged between the locking element 36, in particular, the head portion 42 and the axle shaft 24. While the solenoid 36 is activated, the locking element 36 is held in the locking position by the solenoid 38 against a force exerted on the locking element 36 by the loaded spring 68.
When the solenoid 38 is deactivated the spring will rebound thereby moving the locking element 36 from the locking position back to the released position.
When the differential lock is switched on using, for example, a switch control by the driver of the vehicle, an electrical circuit placed inside the axle housing 16 actuates the solenoid 38. Thereby, the axle shaft 24 is temporarily magnetized and, hence, the locking element 36 is pulled towards the axle shaft 24 and the curvic teeth acting as respective face clutches get engaged. Effectively, the power is transmitted through the spider 30 to the locking element 36 and the axle shaft 24. When the differential lock is turned off, the solenoid 38 is deactivated and the spring 68 helps retract the locking element 36 back to its initial state.
By this mechanism a lot of packaging space can be saved since pneumatic or hydraulic systems mounted on the axles housing 16 are not necessary for locking the differential gear 10. Since electric actuation instead of pneumatic or hydraulic actuation is used to move the locking element 36, the differential gear 10 can be maintained an operated very easily. Moreover, the number of parts of the differential gear 10 can be kept particularly low.
List of reference signs differential gear 12 housing element 14 ring gear 16 housing 18 bavel pinion barring 22 axle shaft 24 axle shaft 26 pinion 28 pinion spider 32 side gear 34 side gear 36 locking element 38 solenoid rod portion 42 head portion 44 bore 48 centre portion receptacle 52 outer circumferential lateral surface 54 external spline 56 inner circumferential lateral surface 58 internal spline fist face side 62 first gear teeth 64 second face side 66 second gear teeth 68 spring

Claims (7)

  1. Claims A differential gear (10) for a vehicle, the differential gear (10) comprising: -at least one housing element (12), -at least one axle shaft (24) being rotatable in relation to the housing element (12), -at least one compensating gear (26) rotatably arranged in the housing element (12), -at least one side gear (34) rotatably arranged in the housing element (12), the side gear (34) meshing with the compensating gear (26) and being connected to the axle shaft (24), -at least one locking element (36) for locking the differential gear (10), the locking element (36) being arranged coaxially in relation to the axle shaft (24) and being capable of being moved between at least one locking position and at least one release position, -at least one solenoid (38) for moving the locking element (36), characterized in that the locking element (36) is arranged at least partly within the axle shaft (24).
  2. 2. The differential gear (10) according to claim 1, characterized in that the locking element (36) has a first face side (60) having first gear teeth (62), the first face side (60) facing a second face side (64) of the axle shaft (24), the second face side (64) having second gear teeth (66), the first gear teeth (62) meshing with the second gear teeth (66) in the locking position.
  3. 3. The differential gear (10) according to any one of claims 1 or 2, characterized in that the differential gear (10) comprises at least one bolt (30) rigidly attached to the housing element (12), the compensating gear (26) being rotatably mounted on the bolt (30) about a rotation axis, the locking element (36) being arranged partly within the bolt (30).
  4. 4. The differential gear (10) according to claim 3, characterized in that the bolt (30) has inner circumferential gear teeth (58) meshing with outer circumferential gear teeth (54) of the locking element (36).
  5. 5. The differential gear (10) according to any one of the preceding claims, characterized in that the axle shaft (24) penetrates the solenoid (38) for moving the locking element (36).
  6. 6. The differential gear (10) according to any one of the preceding claims, characterized in that the solenoid (38) is designed to move the locking element (36) from the release position into the locking position.
  7. 7. The differential gear (10) according to any one of the preceding claims, characterized in that the differential gear (10) comprises at least one spring (68) for moving the locking element (36) from the locking position into the release position.
GB201319067A 2013-10-29 2013-10-29 Differential gear with solenoid operated locking mechanism Withdrawn GB2508978A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB201319067A GB2508978A (en) 2013-10-29 2013-10-29 Differential gear with solenoid operated locking mechanism

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB201319067A GB2508978A (en) 2013-10-29 2013-10-29 Differential gear with solenoid operated locking mechanism

Publications (2)

Publication Number Publication Date
GB201319067D0 GB201319067D0 (en) 2013-12-11
GB2508978A true GB2508978A (en) 2014-06-18

Family

ID=49767303

Family Applications (1)

Application Number Title Priority Date Filing Date
GB201319067A Withdrawn GB2508978A (en) 2013-10-29 2013-10-29 Differential gear with solenoid operated locking mechanism

Country Status (1)

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GB (1) GB2508978A (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3463277A (en) * 1968-03-26 1969-08-26 Int Harvester Co Brake released differential lock
US4625584A (en) * 1984-11-05 1986-12-02 Toyota Jidosha Kabushiki Kaisha Split axle drive mechanism for part-time four-wheel drive vehicle
US20060052207A1 (en) * 2004-09-06 2006-03-09 Masao Teraoka Differential unit

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3463277A (en) * 1968-03-26 1969-08-26 Int Harvester Co Brake released differential lock
US4625584A (en) * 1984-11-05 1986-12-02 Toyota Jidosha Kabushiki Kaisha Split axle drive mechanism for part-time four-wheel drive vehicle
US20060052207A1 (en) * 2004-09-06 2006-03-09 Masao Teraoka Differential unit

Also Published As

Publication number Publication date
GB201319067D0 (en) 2013-12-11

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