JP3528546B2 - Front suspension device for vehicles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front suspension device suitable for vehicles, particularly small buses.

[0002]

2. Description of the Related Art Conventionally, in a front suspension device for a small bus or the like, knuckles of left and right front wheels are pivotally supported at the outer ends of the upper arm and the lower arm in the vehicle width direction, and the inner ends of the upper arm and the lower arm are supported. A leaf spring in which the left and right lower arms are pivotally attached to a suspension cross member that extends in the vehicle width direction below a front end of a side rail of a vehicle body frame, for example, a side rail of the vehicle body frame. Also, a front suspension device which is elastically suspended on the vehicle body side member via a coil spring is known, and is disclosed in, for example, Japanese Utility Model Laid-Open No. 5-12208.

In order to improve the riding comfort of a small bus equipped with the above-mentioned proposed front suspension device, it is preferable to use an air spring in place of the suspension coil spring. Due to restrictions, it is technically possible to arrange an air spring and a height sensor (vehicle height detection device) necessary to restrict the supply and discharge of compressed air to and from the air spring, and an arrangement of related members such as a rod member that operates the height sensor. Have difficulties.

On the other hand, due to road conditions, price, maintenance, and the like, some users desire a small bus or the like having leaf springs and coil springs that are laterally placed as suspension springs, as in the above proposed front suspension device. So, with the one equipped with the above air spring,
It is preferable to manufacture in parallel with a vehicle equipped with a coil spring. In this case, it is possible to reduce the manufacturing cost by sharing the main constituent members such as the suspension cross member, the upper arm, the lower arm, and the vehicle body side member to which these are mounted. It is extremely advantageous in terms of reduction.

[0005]

SUMMARY OF THE INVENTION The present invention was devised in view of the above circumstances, and the main constituent members of the front suspension device are substantially common to both series vehicle models employing a coil spring and an air spring. The main object of the invention is to provide a structure in which an air spring, a height sensor, etc. which cooperate with each other are rationally arranged within the range of the common main constituent members, which is simple, inexpensive and highly reliable. It is a thing.

[0006]

In order to achieve the above object, the present invention provides a suspension cross member arranged in the vehicle width direction and fixed to a member on the vehicle body side, and respective end portions inward in the vehicle width direction. A pair of left and right upper and lower arms pivotally attached to the vehicle body side member and pivotally attached to the knuckles of the left and right front wheels in the vehicle width direction outer end, and an air spring fixed to the upper side surface of the upper arm and the vehicle body side member. An air spring interposed between the bracket and the leaf spring; a leaf spring extending below the suspension cross member in the vehicle width direction and having both ends pivotally attached to the left and right lower arms; Member 's car width
Are provided at both ends in the direction of
When equipped with a suspension coil spring,
An umbrella-shaped bracket that houses the upper part of the le spring,
When equipped with the air spring, the umbrella-shaped bracket
The suspension cross men
Height sensor supported by the sensor bracket via a sensor bracket
A rod member for operating a sensor, one end of which is pivotally attached to the lower arm and the other end of which is connected to an input member of the height sensor, and an output signal of the height sensor is received to supply compressed air to the air spring. The present invention proposes a vehicle front suspension device including a control unit for controlling discharge.

Further, in the present invention, the one end of the sensor operating rod is pivotally attached to a rod bracket attached to a spring seat formed on the lower arm to support the lower end of the coil spring. Preferably.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments in which the present invention is applied to a front suspension device for a small bus, a small truck, etc. will be specifically described below. First, FIG. 1 shows the left front wheel side of the front suspension device.
FIG. 2 is a plan view showing an enlarged main part of FIG. 1. (Note that
Although not shown, the front suspension device on the front right wheel side is formed substantially symmetrically with respect to the vehicle front-rear direction center plane OO in FIG. )

In the drawings, reference numeral 10 indicates a knuckle of a front wheel 12, and the knuckle 10 has a ball joint at an upper portion thereof at an outer end in the vehicle width direction of an upper arm 14 having a substantially V-shaped planar shape. While being pivotally supported via 16, a lower portion thereof is pivotally supported via a ball joint 20 on an outer end portion of a lower arm 18 having a V-shaped planar shape in the vehicle width direction.

Ends 14 'formed on the bifurcated inner side of the upper arm 14 in the vehicle width direction are pivotally supported by both ends of a common upper arm support shaft 22 via rubber bushes known per se. The upper arm support shaft 22 is fixed to a main bracket 26 including a reinforcing plate 24 having a large plate thickness by a plurality of bolts 28.
Reference numeral 6 denotes an appropriate vehicle body side member, in the illustrated case, a plurality of bolts 32 fixed to a side rail 30 having a U-shaped cross section which is arranged to extend in the vehicle front-rear direction and which constitutes a vehicle body frame.

Below the left and right side rails 30, a suspension cross member generally designated by reference numeral 34 is arranged so as to extend in the vehicle width direction, and the suspension cross member has a wide width in the vehicle front-rear direction. Cross member 3
6, left and right vertical members 38 fixed to the main cross member 36 by welding or the like and extending in the vehicle front-rear direction, and arranged substantially parallel to the main cross member 36. And a bracket assembly 42 having an arm bracket 40 fixed to the member 38. The left and right vertical members 38 are fixed to the lower flange of the side rail 30 by a plurality of bolts (not shown). .

The lower arm 18 has a bifurcated end 18 'formed inward in the vehicle width direction, and an end portion 18' formed in the vehicle width direction has an arm bracket 40 of the bracket assembly 42 and the main cross member 36.
Each of them is pivotally supported by a cooperating arm bracket (detailed illustration thereof is omitted) provided on the lower side of the underside through rubber bushes known per se. Further, as well shown in FIG. 1, a leaf spring bracket 44 is projectingly provided on the lower side of the outer portion of the lower arm 18 in the vehicle width direction.

The main cross member 36 of the suspension cross member 34 has a U-shaped cross-section in a plane parallel to the vehicle center plane O--O, with its lower part opened over substantially the entire length. An intermediate portion of a leaf spring 46 that extends in the vehicle width direction and is convexly curved upward is housed in a space that is open downward. Both end portions of the leaf spring 46 in the vehicle width direction are pivotally supported by the leaf spring bracket 44 via ordinary rubber bushes.

A base is provided in the vicinity of the upper surface of the leaf spring 46 which intersects with a plane AA (see FIGS. 2 and 7) which includes the pivot axis of the lower arm inner end portion 18 'and is parallel to the central plane O--O. The stopper rubber 48 is fixed by adhesion, and the stopper 50 is fixed inside the main cross member 36 so as to face the stopper rubber 48. Figure 7
8 and the convex curved surface portion 48 'formed on the upper surface of the stopper rubber 48 and the concave curved surface portion 50' formed on the lower surface of the stopper 50 are the plane A- It is provided so as to abut on A or a portion close to the same plane.

Further, an umbrella-shaped bracket 52 that limits the conical space inside is fixed to the upper side of the end portion of the main cross member 36 that projects outward from the side rail 30, and the umbrella-shaped bracket 52 has its upper end. Part of the main bracket 2
6 is connected and fixed. The upper end of the umbrella-shaped bracket 52 is connected to the upper end of the shaft of a normal tubular shock absorber 54, and the eyeball 54 ′ at the lower end of the shock absorber 54 is connected to the lower arm 18.

A lower substrate 58 of an air spring 56 having a known structure is fixed to the upper surface of the upper arm 14 by a plurality of bolts or screws (not shown) to form a variable volume chamber of the air spring 56. The top plate 62 of the hollow rubber chamber 60 is attached to the main bracket 26 by means of the plurality of bolts 28.
The bolts 3 are fastened together and fixed together with the plurality of bolts 3
The main spring 26 and the side rail 30 are fastened together with the main bracket 26 by an attachment spring bolt 64 or a screw 66. In addition, the air spring bracket 64 includes the hollow rubber chamber 6
An air supply / exhaust port 68 is provided for supplying compressed air to the inside of the hollow rubber chamber 60 or discharging compressed air in the hollow rubber chamber 60 to the outside air.

Below the umbrella-shaped bracket 52 formed at the outer end in the vehicle width direction of the main cross member 36 of the suspension cross member 34, most of the same is shown in particular, as well shown in FIG. A height sensor or a vehicle height detection device 70 is arranged so as to be housed in the umbrella-shaped bracket 52. As shown in the enlarged front view of FIG. 5, the height sensor 70 includes a lever 72 as an input member that rotates in response to a change in vehicle height. A signal transmitter such as a potentiometer that produces an electrically variable vehicle height signal that changes according to height, for example, a voltage signal, is incorporated.

A mounting flange 76 is integrally formed on the casing 74 of the height sensor 70, and the flange 76 is fixed to an appropriate place in the main cross member 36, for example, a side wall of the stopper 50 by welding or the like. It is fixed to the sensor bracket 78 (see FIG. 1) with bolts or the like.
In FIG. 5, reference numeral 80 denotes a harness that accommodates a plurality of electric wires that generate the vehicle height signal and take out the vehicle height signal to the outside.

The lever 72 as an input member of the height sensor 70 is connected to the lower arm 18 by a sensor operating rod member 82 generally indicated by reference numeral 82 in FIG. 1, and the swing displacement of the lower arm 18 is described above. It is transmitted to the height sensor 70 via the lever 72. As shown in FIG. 3, the sensor operating rod member 82 includes an intermediate threaded rod 84 and upper and lower parts respectively screwed into threaded portions formed at the upper and lower ends of the threaded rod 84. Nut portions 86 and 88, lock nuts 90 and 92 for initially setting the screwing position of the nut portions 86 and 88 with respect to the screw rod 84 or adjusting during maintenance, and the nut portion 8
The upper and lower ball joints 94 and 96 are provided at the upper end of 6 and the lower end of the nut portion 88, respectively. The upper ball joint 94 is pivotally attached to the free end of the lever 72.

The lower ball joint 96 of the sensor operating rod member 82 is fixed to the raised side wall portion 100 of the rod bracket 98, and the base plate portion 102 of the bracket 98 is shown in FIG. As described above, the bolts 104 are fixed to the lower arm 18.
The base plate portion 102 is provided with a long hole-shaped through hole 106 through which a lower portion of the shock absorber 54, which is schematically shown by a dashed line in FIG. 3, is inserted.

Further, the bolt 104 of the substrate section 102
When a suspension coil spring (not shown) is arranged substantially coaxially outside the shock absorber 54 in place of the air spring 56 in a series model, a lower spring retainer that supports the lower end of the coil spring is used. Spring seat 18a of the lower arm 18
Lower arm 1 using the mounting bolt holes when mounting on
It is screwed to 8. When the coil spring is provided, an upper portion thereof is housed inside the umbrella-shaped bracket 52, and an upper end of the coil spring is inserted into an upper spring retainer (not shown) inserted into an inner top of the umbrella-shaped bracket 52. Abut. Reference numeral 108 in the figure denotes a rebound stopper rubber attached to the lower surface of the upper arm 14,
110 is a bump stopper rubber attached to the upper surface of the lower arm 18, and 112 is a suspension cross member 34.
3 is an engine mount bracket provided on the upper surface of the main cross member 36 of FIG.

Next, FIG. 6 is a compressed air and electric circuit diagram for controlling the operation of the air spring 56. In this figure, L is added after the numeral representing each component including the air spring to the left front wheel. Of the right front wheel. In the figure, reference numeral 114 is a large-capacity main air tank for storing compressed air discharged from an air compressor driven by an engine of a vehicle or driven by a separate electric motor, 116L and 116R are respectively first solenoid valves, and 118L. And 118R are the second solenoid valve and 120L, respectively.
And 120R are small-capacity auxiliary air tanks interposed between the second solenoid valves 118L and 118R and the air springs 56L and 56R, respectively, and 122 receives the output signals of the height sensors 70L and 70R and receives first and A control unit 124 mounted on a proper place of the vehicle body for energizing or deactivating the second solenoid valves 116L, 116R, 118L and 118R is a vehicle-mounted power source. In addition, 126 is
For example, depending on the vehicle speed, road conditions, weather, etc., the height sensor 70
Reference value of L, 70R, that is, air springs 56L, 56R
This is a correction signal supplying means additionally supplied to the control unit 122 in order to set the reference height, that is, the reference vehicle height in the left and right front wheel suspension portions, to a desired value.

In the above configuration, when the vehicle height of the left and right front wheel suspension portions of a vehicle such as a small bus is a reference value, the lower arm 1
8 by the control unit 122 that receives the output signal of the height sensor 70 operatively connected to the first solenoid valve 11 via the sensor operating rod member 82.
6L, 116R, 118L and 118R are all de-energized, and hollow rubber chamber 6 of air springs 56L and 56R
A set amount of compressed air is supplied to each of 0L and 60R.

During traveling, for example, the vehicle height of the left front wheel 12 becomes lower than the reference value, and the upper arm 14 and the lower arm 1
When 8 rotates in the counterclockwise or upward direction in FIG. 1 about the pivot axis of the respective inner ends 14 'and 18', the sensor actuating rod member 82 connected to the lower arm 18 moves upward. Upon displacement, the lever 72 of the height sensor 70L is rotated counterclockwise in the figure, and an output signal corresponding to the vehicle height deviation from the reference value is supplied from the height sensor 70L to the control unit 122.

As a result, the control unit 122 provides an energizing output to the first solenoid valve 116L which is deenergized at the reference vehicle height and opens the valve, while the second solenoid valve 11L is opened.
No drive output is supplied to 8L, and the valve is maintained in the deenergized state. When the second solenoid valve 118L is deenergized, the first port a and the second port b communicate with each other, and the atmosphere opening c and the second port b are blocked and energized. In addition, the communication between the first port a and the second port b is blocked, and the second port b and the atmosphere opening port c are communicated with each other.

Therefore, the compressed air in the main air tank 114 is supplied to the first port a of the second electromagnetic valve 118L through the first electromagnetic valve 116L, and further from the second port b through the auxiliary air tank 120L to the air spring 56L. Is supplied to the hollow rubber chamber 60L, the air spring 56L extends, and the upper arm 14 and the lower arm 18 via the knuckle 10 respectively rotate clockwise, and the member on the vehicle body side is relatively pushed up. Then, when the vehicle height returns to the reference value, the control unit 122 deactivates the first electromagnetic valve 116L based on the output signal of the height sensor 70L, and the supply of compressed air to the air spring 56L is stopped.

Contrary to the above, the vehicle height of the left front wheel portion becomes higher than the reference value, and the upper arm 14 and the lower arm 18 are
However, when it is rotated clockwise or downward in FIG. 1 around the pivot axes of the respective inner ends 14 'and 18', the sensor actuating rod member 82 is displaced downward, and the height sensor 70L is rotated. The lever 72 is rotated clockwise in the figure, and the output signal corresponding to the vehicle height deviation from the reference value is supplied from the height sensor 70L to the control unit 122.

As a result, the first solenoid valve 116L is maintained in the closed state while being deenergized, and the second solenoid valve 11 is
Since the urging output is provided to 8L, the second solenoid valve 118
The second port b of L communicates with the atmosphere opening port c, and the compressed air in the hollow rubber chamber 60 of the air spring 56L passes through the auxiliary air tank 120L and is discharged to the outside air from the atmosphere opening port c through the second port b. It Therefore, the air spring 5
When 6L contracts, the upper arm 14 and the lower arm 18 via the knuckle 10 respectively rotate counterclockwise, and the vehicle body side member relatively descends downward to return the vehicle height to the reference value. Based on the output signal of the sensor 70L, the control unit 122 deactivates the second electromagnetic valve 118L, and the outflow of compressed air from the air spring 56L is stopped.

The operation of the air spring 56R corresponding to the change in the vehicle height of the right front wheel 12 portion is performed in exactly the same manner as described above, and is independently performed on the left and right sides. In any of the above cases,
It is obvious that the leaf springs 46 arranged in the vehicle width direction share the front wheel load with the air springs 56L and 56R at a preset ratio and act as suspension springs.

According to the above structure, the air spring 56 is mounted on the upper surface of the upper arm 14 and the upper arm 1
4 and the vehicle body side member, that is, the side rail 30 and the bracket 64 connected to the main bracket 26 fixed to the side rail 30, and the height sensor 70 is fixed to the side rail 30.
No. 4, and the other end of the sensor operating rod member 82, one end of which is pivotally attached to the input member 72 of the height sensor 70, is connected to the lower arm 18 in accordance with the vehicle height at the left and right front wheel suspension portions. Receiving the output signal of the height sensor 70 to control the supply and discharge of the working compressed air of the air spring 56 by the control unit 122;
Also, the front wheel load is appropriately distributed and carried by the leaf spring 46 which is placed below the suspension cross member 34 and whose both ends are pivotally attached to the lower arm 18 and the air spring 56.
It is possible to improve the riding comfort of a vehicle such as a small bus, and use a normal suspension coil spring instead of the air spring 56 as the main constituent member of the front suspension device such as the upper arm 14, the lower arm 18, and the suspension cross member 34. It has the advantage that it can be used in common and the manufacturing cost can be greatly reduced.

When a coil spring is used instead of the air spring 56 in the height sensor 70, the height sensor 70 is formed so as to accommodate the upper portion of the coil spring, and is connected to the vehicle body side member via the main bracket 26. By arranging the height sensor 70 below the umbrella-shaped bracket 52, there is no need for a special cover for protecting the height sensor 70 from snow, muddy water, rocks, etc., and the structure can be simplified and the manufacturing cost can be reduced. There is.

Further, when a coil spring is used instead of the air spring 56 for the sensor operating rod member 82 for operatively connecting the input member 72 of the height sensor 70 to the lower arm 18, the lower end of the coil spring is used. By pivotally connecting to the lower arm 18 via a rod bracket having a bolt hole that fits the mounting bolt hole of the spring seat supporting the above, the arrangement of the height sensor 70, together with further simplification and manufacture of the structure. There is an advantage that a cost reduction can be achieved.

By arranging the leaf spring 46 cooperating with the air spring 56 below the suspension cross member 34, the entire front suspension device can be made compact and compact, so that a small bus or the like can be installed in a small space. Since it can be easily mounted on a vehicle with severe restrictions and can be preliminarily formed as a subassembly when the vehicle body is assembled, there is an advantage that assembly workability is improved.

Furthermore, in order to transmit the suspension spring force of the leaf springs 46 placed sideways to the vehicle body side, the pivot end axis of the inner end portion 18 'of the lower arm 18 to the vehicle body side, that is, to the suspension cross member 34 is set. The wear of the abutting portion is achieved by providing the stopper rubber 48 and the stopper 50 cooperating therewith on the plane AA parallel to the central plane of the passing vehicle and the stopper 50 cooperating with the stopper rubber 48, so that the curved surfaces contact each other. There is an additional advantage that the generation of abnormal noise can be effectively suppressed.

[0035]

As described above, the vehicle front suspension device according to the present invention includes a suspension cross member which is disposed in the vehicle width direction and fixed to a member on the vehicle body side, and an inner end in the vehicle width direction. A pair of left and right upper arms and lower arms pivotally attached to the vehicle body side member and the vehicle width direction outer end portions to the left and right front wheel knuckles, and fixed to the vehicle body side member and the upper side surface of the upper arm. An air spring interposed between the air spring bracket, a leaf spring disposed below the suspension cross member and extending in the vehicle width direction, and both ends of which are pivotally attached to the left and right lower arms; A height sensor supported by a sensor bracket fixed to the suspension cross member, and one end pivotally attached to the lower arm and the other end attached to the height sensor. A sensor operating rod member connected to an input member of the sensor, and a control unit for receiving the output signal of the height sensor and controlling the supply / discharge of compressed air to / from the air spring, The ride comfort can be improved by effectively disposing an air spring and a cooperating height sensor etc. in the front suspension device of a vehicle such as a small bus or a small truck which has severe space restrictions and relatively large front wheel loads. The main front wheel suspension members such as the upper arm, lower arm, suspension cross member, etc. can be shared with the series vehicle model in which the air springs are replaced with ordinary coil springs, which is an advantage that manufacturing cost can be effectively reduced. is there.

Further, in the above structure, when the height sensor uses a suspension coil spring instead of the air spring, an umbrella-shaped bracket formed on the suspension cross member to accommodate an upper portion of the coil spring. By arranging in the lower part, there is no need to separately provide a cover that protects the height sensor from snow, muddy water, rocks, etc. to ensure reliability and durability, simplifying the structure and reducing the manufacturing cost. In addition, the one end portion of the sensor actuating rod is pivotally connected to a rod bracket attached to a spring seat formed in the lower arm to support the lower end portion of the coil spring. By wearing it, the coil spring is used instead of the air spring, Achieving minimally kept further structured simplified structural differences between Ron bets suspension system, there is an advantage capable of reducing the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a preferred embodiment of the present invention.

FIG. 2 is a plan view showing only an essential part of FIG.

FIG. 3 is an enlarged plan view of a lower arm 18 in FIG.

FIG. 4 is an enlarged front view of a sensor operating rod member 82 in FIG.

5 is an enlarged front view of the height sensor 70 in FIG.

FIG. 6 is a compressed air and electric circuit diagram for controlling the operation of the air spring 56 in FIG.

7 is an enlarged side sectional view of a spring reaction force transmitting portion of a leaf spring 46 in FIG.

8 is a sectional view taken along the line VIII-VIII in FIG.

[Explanation of symbols]

10 ... Front knuckle, 12 ... Front wheel, 14 ... Upper arm, 18 ... Lower arm, 22 ... Upper arm support shaft, 2
6 ... Main bracket, 30 ... Side rail, 34 ... Suspension cross member, 44 ... Leaf spring bracket, 46 ... Leaf spring, 52 ... Umbrella bracket, 54 ... Shock absorber, 56 ... Air spring, 60 ... Hollow rubber chamber, 64 ... Air spring bracket, 70 ... Height sensor, 72 ... Input member, 82 ... Sensor operating rod member, 114 ... Main air tank, 116
L and 116R ... 1st solenoid valve, 118L and 118R ...
Second solenoid valve, 120L and 120R ... Auxiliary air tank,
122 ... Control unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-147423 (JP, A) Actually open 64-41406 (JP, U) Actually open 6-79609 (JP, U) Actually open 1- 129612 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60G 11/26 B60G 11/36 B60G 11/46 B60G 17/00

Claims (2)

(57) [Claims] 1. A suspension cross member arranged in the vehicle width direction and fixed to a vehicle body side member, and respective inner ends in the vehicle width direction of the suspension cross member are pivotally attached to the vehicle body side member and of the vehicle width direction outer side. A pair of left and right upper and lower arms pivotally attached to the knuckles of the left and right front wheels, an air spring interposed between an upper side surface of the upper arm and an air spring bracket fixed to a vehicle body side member, and the suspension. Leaf springs that extend in the vehicle width direction below the cross member and are pivotally attached at both ends to the left and right lower arms, and at both ends of the suspension cross member in the vehicle width direction.
A suspension coil is provided instead of the air spring.
When equipped with an il spring,
When equipped with the umbrella bracket for housing the upper part and the air spring, the umbrella bracket
The suspension cross men
Height sensor supported by the sensor bracket via a sensor bracket
A rod member for operating a sensor, one end of which is pivotally attached to the lower arm and the other end of which is connected to an input member of the height sensor, and an output signal of the height sensor is received to supply compressed air to the air spring. A front suspension device for a vehicle, comprising: a control unit for controlling discharge. 2. The one end portion of the sensor operating rod is pivotally attached to a rod bracket attached to a spring seat formed in the lower arm to support a lower end portion of the coil spring. The vehicle front suspension device according to claim 1, wherein the front suspension device is a vehicle front suspension device.