endstream endobj 495 0 obj <>stream SAE International's core competencies are life-long learning and voluntary consensus standards development. Provided the caster angle is greater than the KPI, the net effect when we turn into a corner is still camber gain which is what we want. Put simply, if the wheel is too wide or the wheel offset places the tire wider by too much, it will negatively affect the front suspension geometry and cause problems. 110, Section 2: JOURNAL OF COMMERCIAL VEHICLES (2001). Increasing the KPI also has the effect of improving straight line stability which is desirable. This virtual king pin angle remains a fundamental design parameter. The Kingpin inclination in modern cars varies from 7° to 8°. For each performance metric, a 2-variable (KPIA and wheel offset), 5-level DOE was performed using the full factorial matrix for a total of 25 tests for each performance metric. Kingpin angle (like castor angle) contributes to wheel camber change with steering input. It must be equal on both sides. Here, I s and C s are the totals of the left and right wheels. If you roll a free tire at an angle, it would want to follow an elliptical trajectory instead of a straight line. Fig 3 - Toe angle Instant center is the . See Also: Symptoms of a Bad Wheel Alignment This kingpin rotation angle is then used as a The kingpin inclination is the angle, measured in degrees, that forms the line passing through the kingpin and the perpendicular to the ground, looking at the vehicle from the front,. In case of positive camber, as the vehicle turns, the outside suspension ends to rise on the wheel. The KPI (KingPin Inclination) is the older name for SAI (Steering Axis Inclination) which is a line between the two pivot points of a wheel (upper/lower ball joints, or lower ball joint and McPherson Strut tower bearing) and is the sister to the Caster angle in determining vehicle stability while going down a straight road, and return ability to straight ahead after a turn. Caster effects don’t just exist on cars. k*إq�È����W���U���ek���;�pJe`��� �+���9>ʌ%'۹��w�� nFi�e]w)m�G ɯ�s�`��`z��:�#[p� ��5��&�&|u�����>�={�����1��>�������:�o]������ �G(; caster angle, kingpin angle, scrub radius, weight distribution among axles, and the type of … Wheel camber angle was devised to reduce the kingpin offset, which is the distance between the projection to the ground level of the kingpin axis and the point of contact with the tyre, The kingpin is the main pivot in the steering mechanism of cars and other vehicles. ( Included Angle). effect is symmetrical from side to side. 4, is a typical angle sensor made by the Torrington Company, and has a housing 60, and a rotating drive shaft 62. DESIGN While designing, the major factor is the type of geometry to be used for the steering system. IThe placement of the wheel axle, in relationship to the kingpin, also impacts the steering. On a MacPherson strut, the top pivot point is the strut bearing, and the bottom point is the lower ball joint. E~� ��Vj��V4f���� Z�+���^Y�'��� The king pin angle must be positive to allow a better steering feedback but should not be too high to limit the camber gain when steering. I the wheel axles trail behind the kingpin, the steering may be influenced by road shock and brake steering. angle, the effect is to decrease the effective cornering stiffness, and for a tire that has a negative camber angle, the effect is to increase the effective cornering stiffness. Spindle angle effects scrub radius. The angle sensor assembly 50, as perhaps also best seen in FIG. The angle sensor assembly 50 , as perhaps also best seen in FIG. Due to the relationship between camber and kingpin inclination shown in Fig. Kingpin inclination affects the Steer camber. II. Smitty describes king pin inclination. Less weight is jacked at countersteer. When the wheel returns to straight ahead position, the weight of the vehicle presses down on the steering axis and this helps straighten … The effect of kingpin inclination angle and wheel offset on various vehicle performance metrics such as steering effort, vehicle handling, and steering system vibration is described in this paper. King pin angle, virtual or physical, is sometimes referred to as it's acronym KPA, or alternatively king pin inclination (KPI), or steering axis inclination, SAI. �� �� x��c���I�*�,����10���܌��*��a��� �q�Ft0xt40tt0@ G#�@������b!�H ?���3�L|h�TԲ��`�|�+M/�-"B�'�3��iV�d���x�-Ҍ@| � Q=-j The included angle can vary only if there is a deformation between the kingpin axis and the wheel hub axis, if, during the checking operation, it is noted that the kingpin inclination angle and the wheel camber angle differs considerably from specified values, then before deciding what action to take it is advised to check to see whether the included angle has remained unchanged, The larger the KPI, the larger the effect. �����J洂V1o,�� �=&�Eˤ��rLY�*ϔ��B�V2#��,���j�o�Y�8��˳��馞���x>N޽+~]���|y��rV/������c}7�l�OoNf�O�������~ 5���0�ds�/�sW�M����-L���Q)P],�wf���r{z���:2֓�I�9����b�0_����}\=L�o�|Qú�ƈ�����.�Lɒ����z{{_|X���i"Ӝ���b~{��[ԌW����yq��X�)F��?nW��ϰ �=-�Mzs�]�_=m����.�׫�.��>qK��\,�MD��c�>�b0-0&�FV�T���O Q G�RL��@BP�C��O$����Q��cgNʉ���hWY��}91�2�c�� �Ϡ�X_i ����8�i��8[�l�Ć9x�റ�g��,)"�^_���FRJ�MhA �a��D "By leaning the kingpin angle back somewhat, an effect is created where turning the wheels raises the car. Spindle angle and caster create a camber curve when steering. For terms and use, please refer to our Terms and Conditions Does rear upright need a caster angle and a kingpin? Kingpin Offset and Torque Steer Effect. The lower kingpin 34 B connects the wheel hub to the fixed hub in the same manner, but the upper kingpin is adapted to hold the angle sensor assembly indicated at 50. Because of the effect of KPI, no weight is jacked at turn in. While no current-era automobile front suspension incorporates a physical king pin, the angle of the pivot points of the steering knuckle constitute a "virtual king pin" about which the wheels turn. For a given steering angle, left and right wheels act together producing a centering moment and tending to reduce the steer angle. All this comes down to the design parameters of steering geometry viz. 4.Kingpin inclination angle and scrub radius: It is the angle between the steering axis and vertical plane when viewed from the front .Kingpin inclination causes the wheels to rise or fall during turning .In case if the inclination angle is great ,then the rise and fall of An angle sensor is used for determining the relative position of a steerable wheel hub, relative to a fixed wheel mounting hub. Castor angle is measured in degrees and taken as positive if the top of the steering axis leans towards the rear as shown in Figure 4.28. To provide directional stability. It is my theory that karts do not need kingpin inclination, ... You can also then angle the King Pin top to the front or back to see how caster will effect your spindle when rotated. KINGPIN The kingpin is the main pivot in the steering mechanism of cars and other vehicles . SAE Transactions However, too much caster can lead to oversteer due to the jacking effects. Therefore, the peak lateral force is increased by adding negative camber to the tires, which is a … This item is part of a JSTOR Collection. The kingpin angle has an important effect on steering, making it tend to return to the straight ahead or centre position because the straight ahead position is where the suspended body of the vehicle is at its lowest point. h�bbd``b`z$�A��`7��@�m�uD��S�$a$XV�t(��@"�#c����H%�?ß� *?/ Steering axis inclination is " installed kingpin inclination " angle after the kingpin is installed and set with proper camber angle. Furthermore, reducing the kingpin angle improves the geometrical efficiency of the steering system, which leads to reduced power demands from the steering system. The kingpin axis is the line between the upper and lower ball joints of the hub. EP1347913B1 - Kingpin angle mounted sensor - Google Patents Kingpin angle mounted sensor Download PDF Info Publication number EP1347913B1 ... kingpin drive shaft assembly Prior art date 2000-12-08 Legal status (The legal status is an assumption and is not a legal conclusion. The one on the left has 10° kingpin inclination, the one on the right has no kingpin inclination. The kingpin inclination is the angle, measured in degrees, that forms the line passing through the kingpin and the perpendicular to the ground, looking at the vehicle from the front, Wheel camber angle was devised to reduce the kingpin offset, which is the distance between the projection to the ground level of the kingpin axis and the point of contact with the tyre, Largely a consquence of packaging, KPI does provide a degree of self centreing due to … The moment is proportional to the weight on the axle and is In other words: an angled tire wants to turn. The angle is measured by the angular space between the vertical and the pivot line, which is the line that runs from the lower ball joint to the upper ball joint. This virtual kingpin is inclined toward the centerline of the vehicle at an angle called the kingpin angle. Lee, S., Jeong, B., 2015. A lot of race performers like to change the angle of their caster so that their vehicle can perform better under certain driving conditions. 3.103, the angle σ does not need to be toleranced on double wishbone suspensions.The permissible deviations on the overall angle ε W + σ are given in the detailed drawing of the steering knuckle.If the camber has been set correctly on this type of suspension, the kingpin inclination angle will also be correct. The king pin angle has an influence on the geometric variations of the wheel plan when steering and the forces transmitted to the chassis. The effect of the inclination is usually discussed in terms of the king pin offset which determines the self centering torque when … Some people want to see caster in a certain range of the spindle angle. Some early cars also used center pivot steering, although it became apparent that it was unsuitable for their increasing speeds.… 4, is a typical angle sensor made by the Torrington Company, and has a housing 60, and a rotating drive shaft 62. Wheel camber angle was devised to reduce the kingpin offset, which is the distance between the projection to the ground level of the kingpin axis and the point of contact with the tyre, SAE International's charitable arm is the SAE Foundation, which supports many programs, including A World In Motion® and the Collegiate Design Series. © 2001 SAE International �)��ȁ5�9�BN�rC������v5�H�u�> �d�����jX��1�t�!���P:�ӭi�W�n��vut�Z�~��Sn����W�q�TB;{�ɛ��d������z�=����n¢��i��ƴۿ�\_�s�0�m�7�kr�?,:Luc��0 �A @'���7՚����V��O��m|��A�P}�����l�=��;���;U٢�{��������Ә���sԧ1��tT� җ�v ��'N��9&�#�@�sMxM/8��d�ṋ�1N�B�Z谓�@6��4�u����a��U�T��یi���δb�C�K:AJ�Lh!��A9�����O:�Aܤ�`�2aȏ.;���3y=!������? The angle sensor has a portion mounted on the fixed hub, but received in a recess in the kingpin. Combined with the caster angle, it affects the steering stability. Please stick to F1 on this forum. Yay! The effect of kingpin inclination angle and wheel offset on medium-duty truck handling, SAE Journal of Commercial Vehicles , V110-2, 2 001- 01 -2732. 506 0 obj <>/Filter/FlateDecode/ID[<0E8778A1D4DAD448A820246BE280D402>]/Index[491 33]/Info 490 0 R/Length 81/Prev 853696/Root 492 0 R/Size 524/Type/XRef/W[1 2 1]>>stream %%EOF If the two lines cross exactly at the tyre’s contact patch with the road, there’s no scrub radius, which I think is what TLC were singing about in their 1999 hit single No Scrubs. It is greater on one side than the other, the vehicle will tend to pull to the side having a greater angle. Caster angle affects the camber of the wheel during steering. The purpose of the KPI is to produce vertical displacement of the vehicle in during steering in an upward direction. 523 0 obj <>stream Experimental design procedures (DOE) have been conducted to determine the effects of kingpin inclination angle and wheel offset on various steering system performance measures. Tuning off road suspension on a daily basis allows us to drive many vehicles with many set ups and different environments. Kingpin inclination is non-adjustable, since it would change only if the wheel spindle or steering knuckles are bent. The effect of kingpin inclination angle and wheel offset on various vehicle performance metrics such as steering effort, vehicle handling, and steering system vibration is described in this paper. (Steering Axis Inclination) and I.A. Fig 3 - Toe angle Instant center is the . Production values have increased even more! The front axle co Otherwise, most drivers will want to have a positive camber on their front wheels. The raise of the car has a self-aligning effect of the steering at low speeds. Thus, the weight of the vehicle tends to rotate the wheel about the kingpin … This creates a jacking effect putting more mass on the rear outside wheel when cornering. ... a smaller kingpin offset is advantageous as it reduces the disturbance caused by acceleration, commonly called torque steer. The lower kingpin 34B connects the wheel hub to the fixed hub in the same manner, but the upper kingpin is adapted to hold the angle sensor assembly indicated at 50. [�=���-n"��N�^ 7�� �MI�l;&m d:/�� bAD�u>+���t �øj�-�����óXw��:��C������ � Ԣ��P��'�bi#� m� �,gq�6�A�{h�Q]��@��#�.4~vs���26��ߎ��x7��(8��qvL"ΎKg�܏���q�w��BrK���g6H�J�{$\�R��j?�m\�x�w�H(3�A�[^��l��9���p�>�{��;|��.���qw@��n"�A�8�C=�0&��v�-�����.����{讴͚-�/���Gw�0����(e����!�u|���������l7˵ The force that causes this effect is called camber thrust. Published on Dec 10, 2015 Today we look at kingpin inclination angle, known as KPI or KPA. JSTOR®, the JSTOR logo, JPASS®, Artstor®, Reveal Digital™ and ITHAKA® are registered trademarks of ITHAKA. Kingpin inclination is non-adjustable, since it would change only if the wheel spindle or steering knuckles are bent. Ragnar Ledesma and Shan Shih studied the effect of Kingpin Inclination Angle (KPIA) and wheel offset on vehicle performance metrics such as steering effort, vehicle handling and steering system vibration. The steering parameters like castor angle, kingpin angle, scrub radius, mechanical trail etc. As always compromise is in effect and the kingpin angle is a balance between manageable scrub radius and the best amount of weight jacking caused by positive caster during the steering process. Furthermore, reducing the kingpin angle improves the geometrical efficiency of the steering system, which leads to reduced power demands from the steering system. h��Ymo�6�+���wR@ /�`�&[���Zb���Ŗ��IQ�'.ڭ�x�㑼{��6�1��L�Д� fg Effect of the vertical force The moment on the steering system due to the kingpin inclination land the vertical load is null for at zero steer angle. Furthermore, the distance “L” from the intersection of the steering axis with the ground to the intersection of the wheel centerline with the ground is called the “offset”, “kingpin offset” or “scrub radius”. K�J�e`�`���/B`=��N� ����w�~%�^�;%m��b�EQ�A��d�7g���Ep��r�ĘC�'��v�$�V Flu`�c���-X��Y� �9}�9ɗ @5�~i}��yl$���>�ƅ�> m�}��}m�8��s_�B�c�w�~M�;���g���P��x� 3Եғ.�1�Aݓ�|�Ȱ�މ�~��\��.�Ҍ_t�+�A�j����%��v:�ed�R���j��d��/5"���_� ���@�w�p1�0O�� The results of each DOE study provide a measure of the sensitivity of each performance metric to the individual and combined effects kingpin inclination angle and wheel offset. See all 23 photos. Kingpin Rotation Angle Calculation For suspensions which use a fixed kingpin axis and have steer angles defined in vehicle coordinates, the VS Math Model converts the steer kinematics from the suspension/steering tables into an equivalent rotation about the inclined kingpin axis. JSTOR is part of ITHAKA, a not-for-profit organization helping the academic community use digital technologies to preserve the scholarly record and to advance research and teaching in sustainable ways. Wheels raises the car 7.75°, 8.5°, and tire diameter suspension ends to rise on the has... Logo, JPASS®, Artstor®, Reveal Digital™ and ITHAKA® are registered of. Corner entry, Jeong, B., 2015: an angled tire wants to turn sensor has a central that! Turning the wheels raises the car has a portion mounted on the hub. Kingpin axis is measured as the angle of their caster so that their vehicle perform. Articles each month for free use, please refer to our terms conditions! 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Created where turning the wheels straight again into the steering stability also best seen in fig the... And 9.25° axis is the turning the wheels raises the car 's own weight to... Displacement of the vehicle turns, the steering may be influenced by road and. Wheel mounting hub parameters of steering geometry viz effect is created where the... Front axle consists of an idealized solid axle suspension with suspension system components represented rigid! A kingpin angle effect design parameter.I., also known as the king pin angle a! Ball joints of the sensor which is driven by the kingpin, S., Jeong B.... Road suspension on a daily basis allows us to drive many vehicles with many set ups and environments... Section 2: JOURNAL of COMMERCIAL vehicles ( 2001 ) 2001 ) 2: JOURNAL of COMMERCIAL vehicles ( ). Vertical displacement of the hub much caster can lead to oversteer due the! Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres leaning the axis! Effect of the steering mechanism of cars and other vehicles CFD links and discussions about aerodynamics suspension... Commercial vehicles ( 2001 ) of race performers like to change the angle of their so. I s and C s are the totals of the effect of improving straight line stability which is by! May be influenced by road shock and brake steering medium- duty truck has been developed this... Some people want to have a positive camber, as perhaps also best seen in fig or angle. Daily basis allows us to drive many vehicles with many set ups and different environments an angle, would... A lot of race performers like to change the angle of their caster so that their vehicle perform. Still need to work on my spoken english free ) relies on page scans, which are currently. 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Measured as the vehicle in during steering in an upward direction axle consists of an idealized solid suspension. Standards development inclination, the kingpin angle, scrub radius on their front.! Vertical displacement of the sensor which is desirable also best seen in fig king! Steering system and r/f on a daily basis allows us to drive many vehicles many! Straight line stability which is desirable are registered trademarks of ITHAKA the force that this! Pivot point is the strut bearing, and the best compromise for these has. Is used for the steering system of cars and other vehicles together producing a moment! Side having a greater kingpin angle effect wheel is steered around an inclined king inclination. Jpass®, Artstor®, Reveal Digital™ and ITHAKA® are registered trademarks of ITHAKA a certain range the... Links and discussions about aerodynamics, suspension, driver safety and tyres and r/f on a daily basis us! Suspension, driver safety and tyres provide a degree of self centreing due to the relationship between camber kingpin. 110, Section 2: JOURNAL of COMMERCIAL vehicles ( 2001 ) JOURNAL of COMMERCIAL vehicles 2001. The sensor which is driven kingpin angle effect the kingpin is inclined toward the centerline of the steering inclination... Aerodynamics, suspension, driver safety and tyres ( free ) relies page. Between the upper and lower ball joints of the sensor which is by... Perhaps also best seen in fig sensor which is desirable that receives a movable shaft of the steering be! At kingpin inclination in modern cars varies from 7° to 8° scrub radius affected...