125 Semitrailingarm rear axles

This is a special type of trailing-arm axle, which is fitted mainly in rear-wheel and four-wheel drive passenger cars, but which is also found on front-wheel drive vehicles (Fig. 1.15). Seen from the top (Fig. 1.16), the control arm axis of rotation EG is diagonally positioned at an angle a 10 to 25 , and from the rear an angle ( 5 can still be achieved (Fig. 3.36). When the wheels bump and Fig. 1.15 Tilted-(Multiple) Staft Steering Rear Axle of the Opel Omega (1999), a further development of...

512 Running wheel comfort

Even smooth-looking road surfaces have almost invisible slight irregularities and bumps which are transferred to the body as high frequency acceleration and jolts (4-80 Hz). The vehicle occupants feel them in the underbody of the vehicle, in the seat cushion, and the driver also feels them in the steering wheel and the pedals. They determine the wheel comfort and the concomitant road harshness. The cause of this is the often limited vibration insulation between the suspension parts and the...

163 Driven front axles

The following are fitted as front axles on passenger cars, estate cars and light commercial vehicles double wishbone suspensions McPherson struts, and (only in very few cases) On double wishbone suspensions the drive shafts require free passage in those places where the coil springs are normally located on the lower suspension control arms. This means that the springs must be placed higher up with the disadvantage that (as on McPherson struts) vertical forces are introduced a long way up on the...

34 Roll centre and roll axis

In all independent wheel suspensions, there is a direct correlation between the alteration in track and the height of the roll centre, so the two should be examined together. See Refs 2 and 9 for details. According to the German standard DIN 70 000, the body roll centre Ro is the point in the vertical plane which passes through the wheel centre points (Fig. 3.21), and in which transverse forces (y-direction) can be exerted on the sprung mass, in other words the body, without kinematic roll...

122 Double wishbone suspensions

Automobile Engineering Drawing

The last two characteristics above are most easily achieved using a double wishbone suspension (Fig. 1.7). This consists of two transverse links (control arms) either side of the vehicle, which are mounted to rotate on the frame, suspension subframe or body and, in the case of the front axle, are connected on the outside to the steering knuckle or swivel heads via ball joints. The greater the effective distance c between the transverse links (Fig. 1.5), the smaller the forces in the suspension...

51 Comfort requirements

Springing and damping on a vehicle are mainly responsible for ride comfort and dynamic wheel load. They also play an important part in the tendency of the body to roll and pitch. Other important influences on the handling are the kinematic changes, and the elastokinematics, of the wheels as they bump and jounce. Details are given in Chapter 3, and in Refs 2 and 9. The ride comfort experienced by the vehicle occupants depends on their (Stainz) fitting position (Fig. 5.1) - also in relation to...

634 Influence of radiusarm axes

6.3.4.1 Pre-conditions for calculations Radius-arm axes poles are only effective when the brakes are outside the wheel. The entire calculation has to be done differently because not only do the braking force portions of the body Fx,Bo,B,f and Fx,Bo,B,r act at these axes Of (front) and Or (rear), but so do the vertical forces AFz,Bo,B,f and AFz,Bo,B,r acting against brake dive (B axis-related). Figures 3.108 and 3.113 show the static situation and, with Equations 6.13 to 6.16, the braking force...

162 Advantages and disadvantages of frontwheel drive

Regardless of the engine position (see Fig. 1.52), front-wheel drive has numerous advantages there is load on the steered and driven wheels good road-holding, especially on wet roads and in wintry conditions - the car is pulled and not pushed (Fig. 1.35) Fig. 1.51 Gearbox unit on the Lancia Thema, located beside the transverse engine and between the front axle McPherson struts. Owing to the high engine performance, the design features two equal-length axle shafts joined by an intermediate...

28 Lateral force and friction coefficients

2.8.1 Lateral forces, slip angle and coefficient of friction Lateral forces on a rolling tyre can be caused by the tyre rolling diagonal to the direction of travel (so-called slip), the tendency of a tyre to move from its position vertical to the road, camber or conical effects. The build-up of lateral forces as a result of slip will be discussed next. If a disturbing force Fc,v acts at the centre of gravity of the vehicle (e.g. a wind or side negative lift force), lateral wheel forces F,w,f,o,...

164 Nondriven rear axles

Honda Beam Comp Rear Axle Assembly

If rear axles are not driven, use can frequently be made of more simple designs of suspension such as twist-beam or rigid. There are only two load paths available on each side of the wheel in the case of twist-beam axles. As a result of their design (superposed forces in the links, only two load paths), they suffer as a result of the conflicting aims of longitudinal springing - which is necessary for reasons of comfort - and high axle rigidity -which is required for reasons of driving precision...

611 Centre of gravity and handling properties

Depending on the problem posed and the topic, the following are important variables in vehicle engineering vehicle centre of gravity V body (sprung-mass) centre of gravity Bo axle (unsprung mass) centres of gravity Uf or Ur. The distance of the centres of gravity V and Bo from the front or rear axle and their height above ground are crucial for braking and acceleration capacity calculating the climbing ability designing brake systems and four-wheel drives designing body centre of gravity and...

1 2 3 A

Fig. 3.7 Calculation by drawing of Fig. 3.8 Template for easy the alteration in track of a wheel (in the calculation of alteration in track, centre of tyre contact W) and the path can be used on double wishbone of the outer tie rod joint U on the suspensions (Fig. 3.7) and longitudinal double wishbone suspension, using the link axles (Fig. 3.9). template shown in Fig. 3.8. along the arcs around C and D until point W of the template has reached the end of the bump travel s , previously indicated...

142 Nondriven front axles

The standard design for passenger cars that have come onto the market in recent years have McPherson struts on the front axle, as well as double wishbone or multi-link suspensions. The latter type of suspension is becoming more and more popular because of its low friction levels and kinematic advantages. Even some light commercial vehicles have McPherson struts or double wishbone axles (Fig. 1.7). However, like almost all medium-sized and heavy commercial vehicles, most have rigid front axles....

172 Fourwheel drive vehicles with overdrive

Four Wheel Clutch

In four-wheel drive vehicles with overdrive the middle differential is not used. The engine torque is distributed to all four wheels by means of a clutch on the propshaft, as required. The clutch can be engaged manually, or automatically in response to slip. With the use of sprag clutches, which are usually engaged manually, the torque is transmitted in a fixed ratio between the front and rear axles multi-disc or visco clutches permit variable torque distribution. As these systems have...

535 Permissible axle loads

5.3.5.1 According to Section 34 of the German Strafienverkehrs-Zulassungsordnung (StVZO) The permissible axle loads front and rear are specified by the vehicle manufacturer. Several points on which the axle loads have a direct effect must be considered component strength of the body and wheel suspension or axles load capacity and therefore minimum size of the tyres configuration of the brake and brake force distribution (Ref. 6) The permissible axle loads are included in the ABE (Allgemeine...

65 Platform unit assembly and common part systems

The high cost pressure placed on vehicles makes it necessary to have systems able to provide the individuality of products required by clients at a low cost. As in other areas of mechanical engineering, unit assembly and common part systems are more and more frequently being used in vehicle technology within vehicle series or even by different manufacturers within a concern for the purpose of meeting these requirements. These approaches offer the following benefits acquisition of experience of...

311 Antidive and antisquat mechanisms

The anti-dive mechanism reduces the amount by which the front end of the vehicle dips or the tail rises when the brakes are applied. It can - in the case of brakes which are outside in the wheels - only be achieved if there are pitch poles Of and Or between the axles at the front, at the rear, or on both axles (Fig. 3.153). The anti-squat mechanism reduces the amount by which the tail drops on rear-wheel drive vehicles or the front end lifts (on front-wheel drive vehicles). It acts during...

143 Driven rear axles

Rigid Axle

Because of their cost advantages, robustness and ease of repair rigid axles are fitted in practically all commercial and off-road vehicles (Fig. 1.43) in combination with leaf springs, coil springs or air springing (Figs 1.20 and 1.42). They are no longer found in saloons and coup s. In spite of the advantages described in Section 1.3, the weight of the axle is noticeable on this type of vehicle. For independent suspension, the semi-trailing arm axle, shown in Figs 1.15 and 1.45, is used as...

43 Recirculating ball steering

Steering gears with a rotating movement are difficult to house in front-wheel drive passenger cars and, in a standard design vehicle with independent wheel suspension, also require the idler arm 5 (see Fig. 4.3) and a further intermediate rod, position 6, to connect them to the pitman arm 4 the tie rods are adjustable and have pre-lubricated ball joints on both sides (Figs 4.13 and 4.14). This type of steering system is more complicated on the whole in passenger cars with independently...

11 General characteristics of wheel suspensions

The suspension of modern vehicles need to satisfy a number of requirements whose aims partly conflict because of different operating conditions (loaded unloaded, acceleration braking, level uneven road, straight running cornering). The forces and moments that operate in the wheel contact area must be directed into the body. The kingpin offset and disturbing force lever arm in the case of the longitudinal forces, the castor offset in the case of the lateral forces, and the radial load moment arm...

583 Twintube McPherson struts pressurized

The development of the pressurized McPherson strut has met with significant difficulties for many years. Direct transfer of the monotube principle, as used in the shock absorber, is not possible because of the high extension force. There are solutions that keep the rod small and transfer the wheel control to the cylinder tube, but these are expensive and involve high levels of damper friction see Section 6.4.6 in Ref. 5 . The pressurized twin-tube system is a good compromise. Here, the oil is...

Wheel Rim Codes

Disc Type Wheel Fig

Reference to drop base for tyre-fitting number of standard only in Germany can be dropped Fig. 2.22 Marking of the various safety shoulders when used only on the outside of the rim or on both the inside and outside. Normal means there is no safety contour Fig. 2.1 . Further details are contained in standard DIN 7817. Denomination Outside of rim Inside of rim Identification letters One-sided hump Hump Normal H Double hump Hump Hump H2 One-sided flat hump Flat hump Normal FH1 Double-sided flat...

37 Steer angle and steering ratio

References 1 and 9 deal with this area in detail. Section 4.7 covers steering kinematics. When the vehicle is moving very slowly and 'free of lateral forces', it will only corner precisely when the verticals drawn in the middle of all four wheels meet at one point - the centre of the bend M. If the rear wheels are not steered, the verticals on the two front wheels must intersect with the extension of the rear axle centre line at M Figs 3.89 and 1.69 whereby different steer angles Si and Sa,o...

Elastogram In Cellasto

Fig. 5.50 Supplementary spring manufactured by Elastogram in Cellasto polyurethane elastomer on the rear spring dampers of the VW Golf III, 1996 . Material properties and shape make the highly progressive springing curve possible. At 146 mm overall height, it can be compressed by 110 mm and accept an impact load of over 700 kg or a force of Fi 7 kN. Fig. 5.50 Supplementary spring manufactured by Elastogram in Cellasto polyurethane elastomer on the rear spring dampers of the VW Golf III, 1996 ....

221 Diagonal ply tyres

In industrialized countries, cross-ply tyres are no longer used on passenger cars, either as original tyres or as replacement tyres, unlike areas with very poor roads where the less vulnerable sidewall has certain advantages. The same is true of commercial vehicles and vehicles that tow trailers, and here too radial tyres have swept the board because of their many advantages. Nowadays, cross-ply tyres are used only for temporary use emergency spare tyres for passenger cars due to the low...

123 McPherson struts and strut dampers

Rear Pherson

The McPherson strut is a further development of double wishbone suspension. The upper transverse link is replaced by a pivot point on the wheel house panel, which takes the end of the piston rod and the coil spring. Forces from all directions are concentrated at this point and these cause bending stress in the piston rod. To avoid detrimental elastic camber and caster changes, the normal rod diameter of 11 mm in the shock absorber must be increased to at least 18 mm. With a piston diameter of...