Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.

Field of the invention:
[0001] The present invention relates to a rotary damper, and more particularly to the rotary damper that is positioned within a housing of a differential that is secured to wheels of an automobile.

Background of the invention:
[0002] JP 2018105352 A2 describes reducing noise caused by tooth striking of a pinion and a ring gear of a crank-type transmission unit with a simple structure. A gear change actuator 30 includes uncoupling mechanisms composed of planetary gear mechanisms, and a deceleration mechanism, and the uncoupling mechanisms PGS1, PGS2 rotate a transmission shaft 15 at a speed same as an input shaft in stopping an electric motor, and generate differential rotation between the transmission shaft and the input shaft in driving the electric motor. As a damper 57 is disposed on a connection member 54 for connecting the uncoupling mechanisms to the transmission shaft, impact shock due to tooth striking of a pinion 18 and a ring gear 19b is damped by the damper while unifying transmission torques to transmission units by securing torsional rigidity of the transmission shaft, thus the tooth striking can be reduced, and further as the damper is disposed inside of the gear change actuator, a structure of a continuously variable transmission can be simplified and miniaturized, and assembly can be improved.

Brief description of the accompanying drawings:
[0003] An embodiment of the disclosure is described with reference to the following accompanying drawing:

[0004] FIG. 1 illustrates a schematic diagram of a differential comprising a rotary damper that is positively secured between opposing ends of a differential pinion in one embodiment of the invention.

Detailed description of the embodiments:
[0005] FIG. 1 illustrates a differential 100 for an automobile. The differential 100 comprises a ring gear 110 mounted on the housing 120 and secured thereto. A driving pinion gear 118 is adapted to mesh with the ring gear 110, the driving pinion gear 118 adapted to mesh with the ring gear 110 to facilitate driving the ring gear 110. A housing 120 of the differential 100 is secured to the ring gear 110, the housing 120 of the differential 100 and the ring gear 110 are adapted to rotate about a common axis. The housing 120 of the differential 100 is adapted to be rotated about an axis of the ring gear 110 due to a rotation of the ring gear 110. A first differential side gear 122 and a second differential side gear 124 are separated from one another and positioned within the housing 120. The first differential side gear 122 and the second differential side gear 124 are adapted to rotate about an axis of the housing 120 when the housing 120 rotates to transmit power from the differential 100 to the left wheel 114 and to the right wheel 116 of the automobile. A first differential pinion 126 and a second differential pinion 128 are separated from one another and positioned within the housing 120. The first differential pinion 126 is adapted to mesh against the first differential side gear 122 and the second differential side gear 124. The second differential pinion 128 is adapted to mesh against the first differential side gear 122 and the second differential side gear 124 such that when the first differential pinion 126 and the second differential pinion 128 are stationary, power is transmitted equally between the left wheel 114 and the right wheel 116 of the automobile. When the first differential pinion 126 and the second differential pinion 128 are rotated at equal speeds, the left wheel 114 is rotated at a speed that is proportionately higher/lower than that of the right wheel 116. A rotary damper 150 is positively secured to an end of the first differential pinion 126 at its first end and positively secured to an end of the second differential pinion 128 at its opposite second end. The rotary damper 150 is adapted to control a transmission of power from the differential 100 to the left wheel 114 and to the right wheel 116 respectively.

[0006] FIG. 1 illustrates a differential 100 for an automobile. The differential 100 comprises a ring gear 110 that is mounted on the housing 120. The axle shaft 112 is secured to the left wheel 114 of the automobile and to the right wheel 116 of the automobile respectively. A driving pinion gear 118 is adapted to mesh with the ring gear 110. More specifically, the driving pinion gear 118 is adapted to mesh with the ring gear 110 such that the driving pinion gear 118 drives the ring gear 110. In an exemplary embodiment, a housing 120 of the differential 100 is secured to the ring gear 110. More specifically, the housing 120 of the differential 100 is adapted to be rotated about an axis of the ring gear 110 due to a rotation of the ring gear 110. Therefore, when the ring gear 110 rotates which causes a rotation of the axle shaft 112, the housing 120 of the differential 100 and the ring gear 110 are adapted to rotate together. A first differential pinion gear 126 is positioned within the housing 120 and secured to the housing 120 of the differential 100 that is secured to the ring gear 110. A second differential pinion gear 128 is positioned within the housing 120 and secured to the housing 120 of the differential 100 that is secured to the ring gear 110. The first differential pinion gear 126 and the second differential pinion gear 128 are separated from one another and are each secured to a shaft 160. A first differential side gear 122 is positioned within the housing 120 and secured to the housing 120 via a first bearing (not shown) of the differential 100 that is secured to the housing 120. A second differential side gear 124 is positioned within the housing 120 and secured to the housing 120 via a second bearing (not shown) of the differential 100 that opposes the ring gear 110. The second differential side gear 124 is separated from the first differential side gear 122 by a spacing and are each positioned within the housing 120 of the differential 100. The first differential side gear 122 is adapted to rotate about an axis of the housing 120 when the housing 120 rotates to transmit power from the differential 100 to the left wheel 114 and to the right wheel 116 of the automobile. Similarly, the second differential side gear 124 is adapted to rotate about an axis of the housing 120 when the housing 120 rotates to transmit power from the differential 100 to the left wheel 114 and to the right wheel 116 of the automobile.

[0007] In an exemplary embodiment, the first differential pinion 126 is adapted to mesh against the first differential side gear 122 and the second differential side gear 124 respectively. Similarly, the second differential pinion 128 is adapted to mesh against the first differential side gear 122 and the second differential side gear 124 respectively such that when the first differential pinion 126 and the second differential pinion 128 are stationary, power is transmitted equally between the left wheel 114 and the right wheel 116 of the automobile. When the first differential pinion 126 and the second differential pinion 128 are rotated at equal speeds about their respective axes, the direction of rotation of the first differential side gear 122 is opposite to the direction of rotation of the second differential side gear 124. Therefore, due to the direction of rotation of the first differential side gear 122 being opposite to the direction of rotation of the second differential side gear 124, one of the wheels of the automobile is speeded up while the other wheel of the automobile is speeded down. When the first differential pinion 126 and the second differential pinion 128 are rotated at equal speeds in the same direction, the left wheel 114 is rotated at a speed that is proportionately higher/lower than that of the right wheel 116 relative to the mean speed of the left wheel 114 and the right wheel 116 respectively.

[0008] In an exemplary embodiment, a rotary damper 150 is positively secured to an end of the first differential pinion 126 at its first end. Similarly, the rotary damper 150 is positively secured to an end of the second differential pinion 128 at its opposite second end. The rotary damper 150 is adapted to control a transmission of power from the differential 100 to the left wheel 114 and to the right wheel 116 respectively for different operating conditions of the automobile as will be explained in more detail below.

[0009] In an exemplary embodiment, the rotary damper 150 that is positively secured to an end of the first differential pinion 126 at its first end extends between the first differential pinion 126 and the second differential pinion 128 and is positively secured to an end of the second differential pinion 128 at its opposite second end. The rotary damper 150 offers maximum rotational resistance, thereby reducing the difference in velocity between the first differential side gear 122 and the second differential side gear 124. More specifically, when one of the wheels rotates on a slippery surface such as on a sheet of ice, and the other rotates on a surface with considerably higher grip such as concrete, there exists a tendency for the difference in speed between the left wheel 114 and the right wheel 116 to be maximum. More specifically, the wheel that is positioned on the slippery surface receives maximum power due to the rotation of the ring gear 110 while the wheel that is positioned on the rough surface such as on a concrete surface receives no power from the ring gear 110. The maximum rotational resistance of the rotary damper 150 that is positioned between the first differential pinion 126 and the second differential pinion 128 enables an equal transmission of power to the left wheel 114 and to the right wheel 116 of the automobile respectively. Therefore, the wheel that is positioned on the rough surface such as on the concrete surface receives a proportion of power from the wheel that is positioned on the slippery surface, thereby enabling the wheel that is positioned on the rough surface to rotate and propel the automobile forward.

[0010] In an exemplary embodiment, the rotary damper 150 that is positively secured to an end of the first differential pinion 126 at its first end extends between the first differential pinion 126 and the second differential pinion 128 and is positively secured to an end of the second differential pinion 128 at its opposite second end. The rotary damper 150 offers a rotational resistance less than the maximum value, due to a difference in velocity, which is less than the maximum value, between the first differential side gear 122 and the second differential side gear 124. More specifically, when the automobile is negotiating a turn at low speed, the wheel of the automobile at the outer circumference of the turn is required to rotate at a higher speed, while the wheel of the automobile that is at the inner circumference of the turn is required to rotate at a lower speed to ensure no slip between the inner wheel and the road. Therefore, the difference in speeds between the wheels of the automobile at the outer circumference of the turn and at the inner circumference of the turn is required to be maintained at a positive value which varies depending on the radius of the turn. However, prior to negotiating the turn at the low speed, the difference in the speeds between the wheels of the automobile is equal to zero. More specifically, the wheel that is positioned on one side of the automobile receives the same amount of power due to the rotation of the ring gear 110 as that of the wheel that is positioned on the other side of the automobile. While negotiating the turn at low speeds, the rotational resistance of the rotary damper 150 is equal to a value lower than the maximum, as the difference in speeds between the left wheel 114 and the right wheel 116 of the automobile is less than the maximum value. The rotational resistance of the rotary damper 150 that is positioned between the first differential pinion 126 and the second differential pinion 128 enables a difference in speed between the left wheel 114 and the right wheel 116 respectively. Therefore, the wheel of the automobile that is located at the outer circumference of the turn is rotated at the higher speed, while the wheel of the automobile that is located at the inner circumference of the turn is rotated at the lower speed, thereby avoiding slippage between the inner wheels of the automobile and the ground. More specifically, the rotational resistance of the damper 150 is between its maximum and minimum values, because the difference in speeds between the left wheel and the right wheel is between the maximum and minimum values. Due to the first differential side gear 122 and the second differential side gear 124 that rotate at equal speeds in opposite directions, unequal transmission of power to the left wheel 114 and to the right wheel 116 respectively is enabled, thereby enabling a positive difference in speeds between the two wheels of the automobile.

[0011] A working of the rotary damper 150 that is positioned within the housing 120 of the differential 100 that is secured to wheels of the automobile is described as an example. When the wheels of the automobile are at their highest relative speeds such as when one of the wheels of the automobile is on a slippery surface such as on a sheet of ice, while the other wheel is on a hard surface such as on a slab of concrete, the power is not transmitted from the first differential pinion 126 and the second differential pinion 128 to the first differential side gear 122 and to the second differential side gear 124 respectively. More specifically, the rotary damper 150 offers maximum rotational resistance, thereby reducing a difference in speeds between the left wheel and the right wheel of the automobile. Therefore, the two wheels of the automobile are adapted to receive equal power from the first differential side gear 122 and the second differential side gear 124 to rotate at equal speeds, thereby permitting the wheel of the automobile that is on the slab of concrete to rotate and thereby propel the automobile forward. When the wheels of the automobile are at their lowest relative speeds such as when both of the wheels of the automobile are translating along a straight path, the power is transmitted equally between the two wheels of the automobile. When the vehicle is negotiating a turn, the wheel that is secured to the outer periphery of the automobile rotates at a higher speed than the wheel that is secured to the inner periphery of the automobile such that the relative velocities between the two wheels is not at its maximum value. In this instance, the damper would offer a certain amount of rotational resistance with some flexibility, to enable first differential side gear 122 that is mechanically connected to the first differential pinion 126 to rotate in a direction that is opposite to a direction of rotation of the second differential side gear 124. However, the increase in the speed of the first of the two wheels of the automobile from the mean speed of the two wheels of the automobile is proportional to the decrease in the speed of the second of the two wheels of the automobile. Therefore, the two wheels of the automobile are adapted to receive unequal power from the first differential side gear 122 and the second differential side gear 124 to rotate at unequal but proportional speeds, thereby permitting the wheel of the automobile that is on the outer periphery of the automobile to rotate at a greater speed that the wheel of the automobile that is on the inner periphery of the automobile and preventing the left wheel 114 and the right wheel 116 of the automobile slipping relative to one another as the automobile turns.

[0012] It should be understood that the embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.
, Claims:We claim:

1. A differential (100) for an automobile, said differential (100) comprising:
a ring gear (110) mounted on a housing (120) ;
a driving pinion gear (118) adapted to mesh with said ring gear (110), said driving pinion gear (118) adapted to mesh with said ring gear (110) to facilitate driving said ring gear (110);
said housing (120) of said differential (100) secured to said ring gear (110), said housing (120) of said differential (100) and said ring gear (110) adapted to rotate about a common axis, said housing (120) of said differential (100) adapted to be rotated about an axis of said ring gear (110) due to a rotation of said ring gear (110);
a first differential side gear (122) and a second differential side gear (124) separated from one another and positioned within said housing (120), said first differential side gear (122) and said second differential side gear (124) adapted to rotate about an axis of said housing (120) when said housing (120) rotates to transmit power from the differential (100) to the left wheel (114) and to the right wheel (116) of the automobile;
a first differential pinion (126) and a second differential pinion (128) separated from one another and positioned within said housing (120), said first differential pinion (126) adapted to mesh against said first differential side gear (122) and said second differential side gear (124), said second differential pinion (128) adapted to mesh against said first differential side gear (122) and said second differential side gear (124) such that when said first differential pinion (126) and said second differential pinion (128) are stationary, power is transmitted equally between the left wheel (114) and the right wheel (116) of the automobile due to the rotation of said housing (120) of said differential (100) about the axis of said ring gear (110) and when said first differential pinion (126) and said second differential pinion (128) are rotated at equal speeds, the left wheel (114) is rotated at a speed that is proportionately higher/lower than a speed of the right wheel (116); characterized in that
a rotary damper (150) positively secured to an end of the first differential pinion (126) at its first end and positively secured to an end of the second differential pinion (128) at its opposite second end, said rotary damper (150) adapted to offer varying resistive force which controls a degree of transmission of power from said differential (100) to the left wheel (114) and to the right wheel (116) respectively.

2. The differential (100) for the automobile in accordance with Claim 1, wherein said rotary damper (150) that is positively secured to an end of the first differential pinion (126) at its first end and positively secured to an end of the second differential pinion (128) at its opposite second end offers maximum resistive force when the difference in speed between the left wheel (114) and the right wheel (116) is maximum, thereby reducing a difference in speeds of the left wheel and the right wheel to a minimum.

3. The differential (100) for the automobile in accordance with Claim 1, wherein said rotary damper (150) that is positively secured to an end of the first differential pinion (126) at its first end and positively secured to an end of the second differential pinion (128) at its opposite second end offers a resistive force lesser than its maximum when a difference in speed between the left wheel (114) and the right wheel (116) is required such as while negotiating a turn.