JPS643684B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a suspension system in which each axle is supported by a balance beam in a large vehicle having four adjacent axles, two of which serve as single-wheel steering axles. It is related to the device.

In large vehicles such as truck cranes, which have a large gross vehicle weight, the number of axles is increased to reduce the axle load, such as two or three axles in the front and four axles in the rear. In such cases, all rear axles are generally double-wheeled, but in order to reduce the tire slip angle and minimize the minimum turning radius, the two axles at the front and rear may be used as steering axes. many. In such a case, it is desirable to basically set the axle load ratio of each axle to 0.5:1:1:0.5, corresponding to the number of wheels.

However, when driving on general roads,
For example, when driving over a bridge, the axle load ratio of each axle is sometimes limited to 1:1:1:1 due to the strength of the bridge. In addition, the permissible weight limit for bridge traffic based on laws and regulations is calculated based on the relationship between each axle load and the distance between the axles, so if the front and rear axles are steering axles, the axle load ratio is 1.1 to 1.2: There are some circumstances where setting the ratio to 1:1:1.1 to 1.2 is advantageous because the total vehicle weight can be increased.

Therefore, the present invention aims to provide a suspension system for a large vehicle that can arbitrarily change the axle load ratio of the steering axle in two ways depending on such driving conditions.

Embodiments of the present invention will be described below with reference to the drawings. The present invention can be applied to large-sized vehicles in general, including large-sized construction vehicles such as truck cranes, including trailer-type vehicles.

In Figures 1 and 2, 1 is the vehicle body, 2 is the vehicle body frame, and 3 and 4 are front axles.The front axles 3 and 4 serve as steering axles, and are equipped with single tires 5 and 6. . 7, 8, 9, and 10 are rear axles, of which the center axle 8 and 9 are non-steering axles and have double tires 1.
2 and 13 are mounted, and the frontmost axle 7 and the rearmost axle 10 are steering axles, and single tires 11 and 14 are mounted. In this embodiment, the rear axles 7, 8,
The present invention is applied to suspension systems of Nos. 9 and 10. 15, 15, 16, 16, 17, 17, 1
8, 18 and 19, 19 are a pair of left and right beams, each of which constitutes a balance beam in the lower part of the vehicle body, and each axle 7,
8, 9, and 10 are supported.

The front beam 15 and the rear beam 19 have brackets 22 and horizontal pins 23 at their respective midpoints.
It is attached to the lower surface of the vehicle body frame 2 via
Each of them can rotate about a horizontal pin 23 as a fulcrum. The front end of this front beam 15 is connected to the front axle 7, and the rear end of the rear beam 19 is connected to the rear axle 1.
0, and the intermediate portions of the intermediate beams 16, 18 are connected to the central second and third wheels 8, 9 with brackets 32, 33, 34 and horizontal pins 33, 25, respectively.
Pivotally connected via. Beam 17 in the center
is the middle part of the bracket 26 and the horizontal pin 2
attached to the lower surface of the vehicle body frame 2 via 7,
It is designed to be able to rotate about a horizontal pin 27 as a fulcrum. In order to connect the beams 15 to 19, they are pivotally connected via a connecting link 28 and horizontal pins 29, 29, as shown in FIG.

In this way, a basic axle support mechanism using a balance beam is constructed. In such a configuration, as shown in FIG. 3, the distance from the swinging fulcrum to the acting points on both sides of each beam 15 to 19, that is, the arm lengths P, Q, R, ...X, Y. It is set under the following conditions.

P:Q=1/{(1+i)L} R:S=i T:U=j V:W=1+i-ij/ij X:Y=M(1+i)/1+i−ij far.

With this setting, when the unit axle load of the front axle 7 is L, the front beam 15 and the intermediate beam 1
The load acting on the connecting link 28 that connects 6 is 1/(1+i). And intermediate beam 16
The load acting on the connecting link 28 connecting the intermediate beam 17 and the central beam 17 is as follows, depending on the arm ratio i of the intermediate beam 16: {1/(1+i)}×i=i/(1+i). Therefore, the axle load of the second central axle 8 is 1/(1+i)+i/(1+i)=1 Also, the load acting on the connecting link 28 connecting the central beam 17 and the intermediate beam 18 is According to the arm ratio j of {i/(1+i)}×j=ij/(1+i), the load acting on the connecting link 28 that connects the intermediate beam 18 and the rear beam 19 is the arm ratio of the intermediate beam 18 (1+i−ij)/ From ij, {ij/(1+i)}×{(1+i-ij)/ij=(1+i
−ij)/(1+j) Therefore, the axle load of the third central axle 9 is
ij/(1+j)+(1+i-ij)/(1+i)=1. Due to the arm ratio of the rear beam 19 described above, X:Y=M(1+i)/(1+i-ij), the load acting on the rear axle 10 is: {(1+i-ij)/(1+i)}×{M(1+i) /
(1+i-ij)}=M. Here, each axle 7, 8, 9, 10
The axle load ratio is L:1:1:M.

The values of L and M are based on the assumption that the tires 11, 12, 13, and 14 mounted on each axle 7, 8, 9, and 10 are of the same size (same load capacity), and that each axle 7,
If the strengths of 8, 9, and 10 are also the same depending on the number of tires installed, set 0.5 according to the number of tires. A basic axle load ratio of 0.5:1:1:0.5 is thus obtained.

In addition, if the size of the tires 11, 14 of the front axle 7 and the rear axle 10 or the strength of the axles 7, 10 are different from the tire size or axle strength of the other two-wheeled axles 8, 9, It is sufficient to determine the above L and M values in accordance with the load capacity, etc. In practice, these L and M values should be 0.4 based on 0.5.
It may be set in the range of 0.7 to 0.7.

In this way, by setting the arm ratio of each beam 15 to 19 under specific conditions, each axle 7, 8, 9, 10 when each axle is supported by a balance beam can be
The axle load ratio can be easily and accurately set to a basic value of 0.4-0.7:1:1:0.4-0.7.

Note that the arm ratio setting described above can be applied even when the distance between adjacent axles is different.
Further, specific numerical values of the arm ratios i and j of the intermediate and central beams 16 and 17 can be arbitrarily selected. By selecting these i and j values, the mounting positions of the front, rear and center beams 15, 17, and 19 relative to the vehicle body frame 2, that is, the positions of the brackets 22, 26, and 22, can be selected. Care can be taken to avoid interference.

Further, the detailed structure of each part of the above-mentioned balance beam is as follows.

Intermediate beams 20 and 21 are connected to brackets 3 provided on the lower surface of the vehicle body frame 2.
0, 30 via pins 31, 31, and one end thereof is attached via pins 25, 25.
Brackets 2 provided on axles 8 and 9, respectively
4, 24, and transmits the longitudinal and lateral components of the tire reaction force from the road surface to the intermediate beams 20, 24.
21 is configured to be shared by the vehicle body frame 2.

And front and rear beams 15, 19, center beam 1
As shown in FIG.
The axial clearance between the bracket 21 and the brackets 22, 26, and 30 is set to zero. That is, the bracket 22,
The beams 15 to 21 are attached to the wheels 26 and 30 so as not to be movable in the axle direction. On the other hand, in order to connect the front and rear beams 15, 19 and the axles 7, 10, as shown in FIG.
is connected to the brackets 32, 34 of the axles 7, 10 via a cylindrical sleeve 36, which is a sliding bearing and is fitted onto a spherical bearing 35 and a horizontal pin 33. Thus, the beams 15, 19 and the axles 7, 10
and can be rotated freely forward, backward, left, right, and diagonally relative to each other, and
They are connected so that they can slide in the axle direction.
However, when the left and right corresponding beams are in the same plane, that is, when the left and right tires are at the same height level, the axial directions of the beams 15, 19 and the brackets 32, 34 as shown in FIG. The inner part contacts both the left and right sides.

The lateral component of the tire reaction force from the road surface is transmitted to the frame 2 from this portion.

As mentioned above, the axles 7, 10 are connected to the beams 15, 1
9 so that it can not only rotate freely but also move in the axial direction, the axle can be moved in the axial direction and the rocking displacement of the tires can be easily tolerated when the corresponding tires on both sides swing asymmetrically up and down. This is what I did.

On the other hand, in order to connect each of the intermediate beams 16, 18, 20, 21 to the axles 8, 9, each of the beams 16, 18 is fitted onto a spherical bearing 35 and a horizontal pin 25, as shown in FIG. It is connected to the brackets 24 of the axles 8, 9 via a cylindrical sleeve 36 as a sliding bearing. Thus, beam 16,1
8, 20, 21 and axles 8, 9 are connected to each other so that they can freely rotate back and forth, right and left, and diagonally, and can slide in the axle direction. However, when the left and right corresponding beams are in the same plane, that is, when the left and right tires are at the same height level, the axially inner portions of the beams 20, 21 and the bracket 24 as shown in FIG. and are in contact on both the left and right sides. The lateral component of the tire reaction force from the road surface is transmitted from this portion to the frame 2 via the beams 20 and 21.

As mentioned above, the axles 8, 9 are connected to the beams 16, 1
8, 20, and 21 so as to be rotatable as well as movable in the axial direction, the axle can be moved in the axial direction to reduce the rocking displacement of the tires when the corresponding tires on both sides swing asymmetrically up and down. It was made to be easily tolerated. Also, beams 16, 18
is designed to share only the vertical component of the road reaction force.

On the other hand, as shown in FIG. 3, stoppers 37, 38, 39, and 40 are provided on the lower surface of the vehicle body frame 2 at the portions facing the respective axles 7, 8, 9, and 10. 8,9,10
The amount of upward swinging displacement is limited. However, the stoppers 37-40 are provided with a sufficiently large distance from the axles 7-10 so that the amount of upward displacement of the axles 7-10 can be as large as possible when traveling on rough terrain. In addition, stoppers 41 to 44 are provided on the lower surface of the frame at the portions facing the beams 15, 19, 20, and 21 for limiting the amount of downward rocking displacement of the axles 7 to 10 to a relatively small amount.
has been established. These stoppers 41-44 and 15, 19, 20, 21 control the axles 7-10.
The amount of vertical rocking displacement of the balance beam is regulated to an extent that does not cause strain on each part of the balance beam.
By keeping the amount of downward displacement of the axles 7 to 10 small, it is possible to prevent the tire from falling onto an abnormally low road surface, while by allowing the amount of upward displacement of the axles 7 to 10 to be as large as possible, it is possible to avoid running on rough terrain. In some cases, the axle load can be distributed to a predetermined axle load ratio.

In Figs. 3 and 4, 45 and 46 are radius rods, one end of which is attached to a bracket 47 provided on the lower surface of the vehicle body frame 2, and the other end of which is provided to brackets 48 and 49 provided on the upper surface of the axles 7 to 10, respectively, as shown in Fig. 9. It is attached via a spherical bearing 51 and a horizontal pin 52 having a cushioning material 50 such as rubber attached to the outer periphery. The radius slots 45 and 48 share the longitudinal road reaction force exerted by the driving force or braking force of the vehicle with the beams 15, 19, 20, and 21, and transmit it to the frame 2.

Therefore, in this device, in addition to the basic axle support mechanism using the above-mentioned balance beams, a pair of left and right double-acting hydraulic cylinders 53, 5
3, 66, 66 are interposed, and the cylinders 53, 5
The axle load ratio of the front and rear axles 7, 10 can be changed in two ways, the above-mentioned basic value 0.4-0.7 and 1-1.2, by switching between activation and deactivation of the axles 3, 66, and 66. ing.

In detail, the hydraulic cylinders 53, 53, 66,
66 is attached to the front part of the front beam 15 from the pivot point of the front beam 15 and the rear beam 19 to the rear part of the pivot point of the rear beam 19, and the head side to the body frame 2.
and brackets 54, 55, 67, and 68, respectively.
It is pivotally connected to pins 56, 57, 69, and 70 via a spherical bearing (not shown). A hydraulic circuit for the hydraulic cylinders 53, 53, 66, and 66 is shown in FIG. In the figure, 58 is a hydraulic pump, and its discharge port is connected to hydraulic cylinders 53, 53, 6 through a first switching valve 59 and a check valve 60.
It is connected to the push side (head side) of 6 and 66.
Reference numeral 61 denotes an accumulator in which gas pressure is accumulated, which is connected to the push side of the cylinders 53, 53, 66, and 66, and causes the gas pressure of this accumulator 61 to act on the push side of the cylinders 53, 53, 66, and 66. There is. 62 is an unload valve, and this valve 6
The cylinder pressure is determined by the set pressure in step 2.
Reference numeral 63 denotes a relief valve whose opening pressure is set slightly higher than that of the unload valve 62, and which controls the cylinder pressure when the upward displacement of the front axle 7 and rear axle 10 is extremely large. Prevent excessive rise. 64 is a second switching valve;
A conduit 65 is configured to communicate the pushing side and pulling side of the cylinders 53, 53, 66, and 66 via the cylinder.

In such a configuration, for example, when a construction vehicle is traveling at a work site, the first and second switching valves 59 and 64 are
are set at the positions on the left side of the figure. In this way, all the pressure oil from the pump 58 is unloaded, and both cylinders 53, 53, 66, 6
The push side and the pull side of 6 are in a conductive state. Therefore, the cylinders 53, 53, 66, 66 are inactive. That is, at this time, cylinder 5
3, 53, 66, 66 are rear axle 10 front axle 7
The axles 7, 10 are supported only by the above-mentioned balance beams. Therefore, the axle load ratio of each axle 7 to 10 is the basic value of 0.4 to 0.7:
The ratio is maintained at 1:1:0.4-0.7.

On the other hand, when driving on general roads with the work attachments removed and without significant rolling, the axle load ratio should be set to 1~1 to increase the allowable gross vehicle weight for bridge traffic as much as possible, as described above.
Since it is advantageous to set the ratio to 1.2:1:1:1 to 1.2, the axle load ratio of the front and rear wheels 7, 10 is changed to the appropriate value. In this case, the first and second switching valves 59 and 64 are set to the right position in the figure.
In this way, pressure oil from the pump 58 is supplied to both cylinders 53, and the cylinders 53, 53, 66,
66 operates to bear the axle load of the rear axles 7, 10 together with the balance beam. This hydraulic cylinder 53,5
The load borne by 3, 66, 66 is the difference between the overall axle load of the front and rear axles 7, 10 corresponding to the desired axle load ratio and the axle load borne when supported only by the balance beam. The axle load borne by the cylinder may be converted into cylinder thrust, and the set pressure of the unload valve 62 may be selected based on the cylinder thrust.

Incidentally, the accumulator 61 is operated by the cylinder 6 by vertically swinging the front axle 7 and the rear axle 10.
This provides a buffering effect against the expansion and contraction of the cylinders 66, 66, 53, and 53, and allows the cylinders 66, 66, 53, and 53 to stably support the axle.

In this way, when using this device, the axle load ratio of each axle 7 to 10 is adjusted from 0.4 to 0.4 depending on the driving conditions of the vehicle.
0.7:1:1:0.4~0.7 and 1~1.2:1:1:1
It can be changed arbitrarily in two ways: ~1.2.
Moreover, such a change in the axle load ratio can be applied to cylinders 6 and 6.
This is done by switching between the operating and non-operating states of the hydraulic cylinders 5, 53, and 53, so changing operations are easy, and the hydraulic cylinder 5
Even if an unexpected situation occurs where 3 and 53 become invalid, there will be no safety problem because the balance beams will mechanically support the balance beam.

By the way, in the case of the hydraulic circuit shown in Fig. 10,
Pressure is applied to the pushing side of the hydraulic cylinders 66, 66, 53, 53, but in the hydraulic circuit shown in FIG.
This applies pressure to the pull side. The other configurations are the same as in the case of FIG. With this circuit configuration, the values of L and M (0.4 to 0.7) for the axle load ratio L:1:1:M when supported only by the balance beam are:
Contrary to the case in Figure 10, the cylinders 66, 66, 5
It can be made smaller by the operation of 3 and 53.

As described above, the present invention provides a large vehicle having four adjacent axles, of which the frontmost and rearmost axles are wheel-type steering axles, and the others are double-wheel type non-steering axles. In this system, each axle is supported by a balance beam consisting of five pairs of beams, and a fluid pressure cylinder is interposed between the beam supporting the steering axle and the vehicle body, and this cylinder can be operated and deactivated. By switching between the two states, the axle load ratio of the steering axle can be arbitrarily changed in two ways. According to the present invention, for example, in a construction vehicle such as a truck crane, the axle load ratio can be changed to a value that is advantageous for each of the driving conditions when moving within the site and when driving on a general road, which is convenient for practical use. is extremely large. Furthermore, the axle load ratio can be easily changed simply by switching between cylinder activation and deactivation. In addition, since mechanical support using a balance beam and support using a fluid pressure cylinder are used together, even if the support function of the cylinder is lost, it will not affect the support of the axle, ensuring safety. can be secured.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a side view of the entire vehicle, Fig. 2 is a plan view of the same, Fig. 3 is an enlarged side view of the main parts with the vehicle body and tires omitted, and Fig. 4 is the same. 5 is an enlarged sectional view taken along line 3 in FIG. is an enlarged sectional view along the same line, No. 9
10 is a hydraulic circuit diagram of a hydraulic cylinder, and FIG. 11 is a hydraulic circuit diagram having a circuit configuration different from that in FIG. 10. 1... Vehicle body, 2... Vehicle body frame, 8, 9...
Double-wheel non-steering axle, 7, 10... Single-wheel steering axle, 12, 13... Double-wheel tire, 11, 14...
... Single wheel tire, 15 ... Front beam, 17 ... Center beam, 19 ... Rear beam, 22 ... Body frame beam mounting bracket, 32 ... Axle beam connection bracket, 53 ... Hydraulic cylinder , 58...Hydraulic pump, 59...Switching valve, 61
...Accumulator, 65...Cylinder push/pull communication conduit.

Claims (1)

[Claims] 1. In a large vehicle that has four adjacent axles, of which the front and rear axles are single-wheel steering axles, and the others are double-wheel non-steering axles, a pair of left and right axles are installed at the bottom of the vehicle body. The front, center, and rear beams of each beam group are attached to the lower surface of the vehicle body frame, and the middle beams are attached to the center beam. attached to the lower surfaces of the second and third axles via brackets at their respective intermediate portions so as to be rotatable around a horizontal axis, one end of the front and rear beams and both ends of the central beam to the intermediate beam; The other ends of the front and rear beams are pivotally connected to the front and rear axles, and a fluid pressure cylinder is interposed between the beam supporting the steering axle and the vehicle body frame, and the cylinder is in an operating state. A four-axle suspension system for a large vehicle, characterized in that the axle load ratio of the steering axle can be changed by switching to a non-operating state.