JP4887235B2 - Axle unit structure for air suspension - Google Patents

Description

  The present invention relates to an axle unit structure for an air suspension provided with an air spring used for buses, large trucks and the like.

  FIG. 11 is a perspective view showing a vehicle body (chassis) having a conventional 4-back air suspension axle unit structure (see Patent Document 1).

  As shown in FIG. 11, the vehicle body 90 includes a pair of side members (vehicle frames) 91 extending in the front-rear direction of the vehicle body 90 and two axles for rear wheels extending in the vehicle width direction. Each axle (not shown) is rotatably supported in an axle case 93 that is supported on a vehicle frame 91 by a torque rod 97. Under the axle case 93, spring receivers (beams) 95 that hold air springs 94 at both ends are provided. The air spring (air spring) 94 is fixed to the upper side of both ends of the spring receiver 95 and a part thereof is fixed to the side member 91 on the lower side.

  FIG. 12 is a plan view showing a vehicle (bus) disclosed in Patent Document 2. As shown in FIG.

  A vehicle 100 shown in FIG. 12 includes an air spring 107 of an axle suspension type (rigid type) in which the front axle side 101 is an independent suspension type and the rear wheel axle side is a single axis. A pair of air springs 107 on the rear wheel shaft side are attached to a cross member 103 that hangs on the pair of side members 102, are fixed on a spring receiver 106 on an axle case 104, and are disposed in front of and behind the rear wheel 105.

  The suspension device provided in the vehicle 110 shown in FIGS. 13A and 13B is of a type in which a leaf spring 117 and an air spring 115 are used in combination. The leaf spring 117 is supported at both ends by a pair of brackets 118 provided at the front and rear positions of the wheel 113 of the side member 111, and the center portion is fixed to the axle case 112. One air spring 115 is provided for each leaf spring 117 between the side member 111 and the wheel 113. In the figure, 114 is a fixing member for fixing the lower part of the air spring 115 to the axle case 112, and 116 is a fixing member for fixing the upper part of the air spring 115 to the side member 111.

Japanese Patent No. 3724120 Japanese Patent Laid-Open No. 11-123919 JP 2004-58851 A

  However, in the vehicle 90 of FIG. 11, the air spring 94 is disposed below the side member 91. Although not shown in FIG. 11, in a vehicle such as a heavy truck, a brake chamber for operating an air brake is provided near the tire. Therefore, in order to secure a space for providing the brake chamber near the tire, It is necessary to arrange a pair of air springs 94 at an interval in the front-rear direction. For this reason, the length of the spring receiver 95 carrying the air spring 94 becomes long. When the length L of the spring receiver 95 is long, the bending moment applied to both ends of the spring receiver 95 also increases, and it is necessary to increase the strength of the spring receiver 95, that is, to increase the cross-sectional area. For these reasons, the weight of the spring receiver 95 that supports the air spring 94 is increased.

  Further, the vehicle 90 in FIG. 11 has a smaller distance between the centers of the left and right air springs (air springs) 95 compared to a vehicle having a general leaf suspension (leaf spring). If the distance between the left and right springs is small, the distance between the center position of the tire width (tread, contact surface) and the spring becomes large. Therefore, assuming that the load applied to the axle case is equal between the vehicle having the leaf suspension and the vehicle 90 in FIG. 11, the bending moment applied to the axle case 93 is larger in the vehicle 90 in FIG. 11. This bending moment increases as the distance W between the connection point between the axle case and the suspension and the connection point between the axle case and the wheel (tread) increases. Therefore, in order to ensure the strength of the axle case 93, it is necessary to increase the cross-sectional dimension and thickness of the axle case 93.

  On the other hand, in order to protect the load, there is a method of softening the air spring, that is, reducing the spring constant of the air spring. However, if the distance between the left and right springs 94 is small, the roll spring constant (spring constant for left-right rotation) proportional to the product of the spring constant and the spring center distance is further reduced, and the vehicle body tends to tilt to the left and right. Therefore, it is necessary to attach a stabilizer 99 having high rigidity between the pair of side members 91 to compensate for this.

  In the vehicle of FIG. 12, since the front axle 101 is an independent suspension system, the roll spring constant is not directly related to the distance between the centers of the left and right springs 107, and there is no problem that the roll spring constant decreases. Also, since the front axle 101 is a steering wheel axle, ordinary tires are used as single (one on each side of the axle) and double tires (two on each side of the axle) so that the tire 101a can move easily. The axle weight is smaller than that of the rear axle 104 on which the vehicle is mounted. Therefore, the air spring 101b provided on the front axle 101 is small. Therefore, it is difficult to apply the arrangement of the air spring 101b provided on the front axle 101 as it is to the rigid rear axle 104 side on which a double tire (rear wheel 105) is mounted.

  On the other hand, the air springs 107 provided on the rear axle 104 side are disposed in front of and behind the rear wheel 105, respectively. However, with such an arrangement, the bending moment and roll spring constant acting on the axle case 104 can be improved. However, since the air spring 107 is arranged before and after the rear wheel 105, , And the bending moment acting on the spring receiver 106 becomes large. Therefore, the weight of the spring receiver 106 that supports the air spring 107 is increased in order to increase the strength.

  In addition, the vehicle 100 in FIG. 12 is a rear one-shaft type with one rear axle 104, but when this arrangement is applied to a rear two-axis type vehicle, the distance between the two axes (the distance between the front and rear wheels) is large. As a result, problems such as noise, early wear of tires, and deterioration of fuel consumption due to an increase in road surface resistance during turning occur.

  The suspension of the vehicle 110 shown in FIG. 13 is a combination of a leaf spring 117 and an air spring 115, and the air spring 115 is for assisting (partly undertaking) a load applied to the leaf spring 117. Therefore, it is difficult to achieve the same performance as a complete air suspension. In the vehicle 110 of FIG. 13, it is not realistic to omit the leaf spring 117 and configure the suspension only with the air spring 115 because the size of the air spring 115 becomes very large.

  That is, in a vehicle having a conventional suspension unit structure as shown in FIGS. 11 to 13, the strength of the spring receiver, the axle case, and the stabilizer must be increased. Therefore, these members are heavy and costly. It was something like that.

  Accordingly, an object of the present invention is to provide an axle unit structure for an air suspension capable of solving the above-described problems and making the axle case, the spring receiver and the stabilizer lightweight and inexpensive.

  To achieve the above object, the invention of claim 1 includes a vehicle frame having a pair of side members extending in the front-rear direction of the vehicle body, an axle case supported on the vehicle frame via a torque rod, and housing a rigid axle. In an air suspension axle unit structure provided with an air spring provided between the axle case and the side member for reducing a vertical impact between the axle case and the vehicle frame, the air spring is connected to the side member vehicle. A pair is arranged on the outer side in the width direction and at a position sandwiching the axle case close to the front and rear, and the pair of air springs are fixed to the outer side surface of the side member in the vehicle width direction, respectively, and on the other hand, extended to the upper surface of the axle case A spring receiver for receiving the pair of air springs from below is provided, and the pair of air springs is connected to the axle case via the spring receiver. It is a Ruyunitto structure.

  In the invention of claim 2, the wheels provided at both ends of the axle are double tires, and the space between the pair of side members where the axle case is located is narrowed to form a space for arranging the air spring. The air suspension axle unit structure according to claim 1.

  According to a third aspect of the present invention, each of the wheels provided at both ends of the axle has a single tire that is wide enough to have the same allowable load as that of the double tire and narrow enough to form a space for disposing an air spring. The air suspension axle unit structure according to claim 1.

  According to the present invention, it is possible to use a lightweight and inexpensive axle case and spring receiver, and to exhibit an excellent effect that a stabilizer can be omitted or a lightweight and inexpensive one can be used.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  1 is a perspective view showing a preferred embodiment of an axle unit structure for an air suspension according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a rear front view thereof.

  As shown in FIGS. 1 to 3, the air suspension axle unit structure according to the present embodiment includes a vehicle frame 11 having a pair of side members 12 extending in the front-rear direction of the vehicle body 10, and torque rods 24 and 26 on the vehicle frame 11. An axle case 15 that is supported by the housing and accommodates a rigid axle, and an air spring 18 that is provided between the axle case 15 and the side member 12 to mitigate a vertical impact between the axle case 15 and the vehicle frame 11. With.

  The vehicle frame 11 extends in the front-rear direction (traveling direction) of the vehicle body 10 and includes a pair of side members 12 having a U-shaped cross section and a cross member 13 interposed between the pair of side members 12 and extending in the vehicle width direction. The

  Both base ends of V-shaped torque rods (V rods) 24 are attached via brackets 22 at intersections where both ends of the cross member 13 intersect the side members 12. Further, the tip of the V rod 24 is attached to the upper portion of the housing 15a formed at the center of the axle case 15 via the bracket 23, and is pivotally supported. At the position where the cross member 13 is provided, a bracket 25 extending downward is provided on the outer surface in the vehicle width direction of the side member 12, and one end of a torque rod (side torque rod) 26 is rotatable at the lower end of the bracket 25. Connected. The other end of the torque rod 25 is connected to the axle case 15 via a link member 35 that is rotatable with respect to the axle case 15. The V rod 24 and the torque rod 26 support the axle case 15 so as to be movable only in the vertical direction. Further, in the vicinity of the axle case 15, a stabilizer 29 is stretched over the pair of side members 12 in parallel with the axle case 15.

  In the air suspension axle unit structure according to the present embodiment, a pair of air springs 18 are arranged at positions on the outer side of the side member 12 in the vehicle width direction and between the front and rear of the axle case 15. Are respectively fixed to the outer side surfaces of the side members 12 in the vehicle width direction, and on the other hand, on the upper surface of the axle case 15 are provided spring receivers 19 extending back and forth to receive a pair of air springs 18 from below. A pair of air springs 18 were connected to the axle case.

  Specifically, on the outside of the side member 12, a spring receiver 19 that is long in the longitudinal direction of the vehicle body is fixed to the upper portion of the axle case 15 at the center thereof, and the air springs 18 are respectively provided above the both ends of the spring receiver 19. It is fixed. Each air spring 18 is cylindrical and expands and contracts vertically. The pair of air springs 18 has a size (height) when compressed that is smaller than the height (width in the vertical direction) of the side member 12, and the upper portion of the pair of air springs 18 is connected to the side member 12 via the air spring fixing member 20. 12 is fixed to the outer surface. That is, the air spring 18 is positioned between the wheel 17 and the side member 12 in the vehicle width direction, and is positioned between the upper surface of the side member 12 and the axle case 15 in the vehicle body vertical direction.

  In the present embodiment, the space between the pair of side members 12 where the axle case 15 is located is formed narrow to form a space for arranging the air spring 18. Specifically, the interval of the rear portion 34 between the pair of side members 12 is made narrower than the interval of the front portion 33. The rear part 34 here is a part where two axles (rear two axles) for rear wheels are provided, and the front part 34 is a part where an axle for front wheels is provided. By making the distance between the rear portions 34 of the side members 12 smaller than the distance between the front portions 34, the air spring 18 is arranged between the wheels 17 and the side members 12 in the vehicle width direction without changing the distance between the left and right wheels 17. Has been established.

  In the present embodiment, the wheels 17 provided at both ends of each axle are double tires each having two tires attached to both ends of the axle.

  FIGS. 4 to 6 are views in which the wheel 17 is omitted from the vehicle body 10 of FIGS. 1 to 3, FIG. 4 is a perspective view thereof, FIG. 5 is a plan view thereof, and FIG. However, the distance between the pair of side members 12 is uniform.

  As shown in FIGS. 4 to 6, a wedge brake 31 is provided in the vicinity of the wheel of the axle case 15 and on the outer side in the vehicle width direction of the side member 12, and the wedge brake 31 is provided at the rear of the axle and on the lower surface of the side member 12. A brake chamber (air chamber) 32 serving as an actuator is provided.

  A damper 28 is attached to the inside of the side member 12 above the axle case 15, and the damper 28 is also fixed to the axle case 15.

  Next, the operation of the present embodiment will be described.

  The axle unit structure for an air suspension of the present embodiment is configured such that a pair of air springs 18 are disposed at positions on the outer side in the vehicle width direction of the side member 12 and between the axle case 15 close to the front and rear. The distance between them is small. Since the spring receiver 19 receives an impact applied from the air spring 18 at both ends (input points) and is supported by a connecting portion (support point) with the axle case 15, the length of the spring receiver 19 in the longitudinal direction of the vehicle body is long. The longer the distance, that is, the longer the distance between the input point and the support point, the greater the strength (impact resistance) of the spring receiver 19 must be. In the present embodiment, the distance L1 between the input point and the support point is made small, that is, the length L1 of the spring receiver 19 on which the air spring 18 is mounted is made smaller than before. Accordingly, the bending moment applied to the spring receiver 19 is reduced, and it is not necessary to increase the cross-sectional area of the spring receiver 19 so as to have a strength that can withstand the bending moment. Therefore, the length and the cross-sectional area of the spring receiver 19 can be reduced, and the lightweight and inexpensive flash receiver 19 can be used.

  Next, an axle unit structure for an air suspension according to another embodiment will be described.

  As shown in FIGS. 7 to 9, the basic components of the air suspension axle unit structure of the present embodiment are substantially the same as the above-described suspension unit structure for the suspension of FIGS. The same reference numerals as those in FIGS. 1 to 3 are attached to the parts, but the distance between the pair of side members 42 constituting the vehicle frame 41 is made uniform without changing between the front part and the rear part. This is different from the previous embodiment in that a single tire is wide enough to have the same allowable load as the double tire and narrow enough to form a space for placing the air spring 18.

  In the present embodiment, the distance between the pair of side members 42 is not changed before and after and the wheel 43 is a single tire, so that the vehicle width (the distance between the left and right wheels outside) is maintained and the air spring 18 is The vehicle is disposed between the wheel 43 and the side member 42 in the vehicle width direction and between the upper surface of the side member 42 and the axle case 15 in the vehicle body vertical direction.

  However, as shown to Fig.10 (a), the width | variety of the single tire of this embodiment is narrow compared with the width | variety (total of two tires) of the double tire which is the wheel 17 of previous embodiment. However, it is a single tire that is wide enough to have the same allowable load as a double tire. Note that FIG. 10B is that of the previous embodiment, and is shown side by side for comparison of the wheel width (in FIG. 10B, W1 is the center position of the width of the wheel 17 and the vehicle of the air spring 18). Distance from the center position in the width direction).

  In the present embodiment, as in the previous embodiment, in addition to the effect that the light and inexpensive spring receiver 19 can be used, by using a single tire having the same allowable load and the same diameter, the center position of the width of the wheel 43 is obtained. And the distance W2 between the center position of the air spring 18 in the vehicle width direction can be made smaller than before. Therefore, if the same load as before is applied, the present embodiment in which the distance W2 between the center position of the width of the wheel 43 and the center position in the vehicle width direction of the air spring 18 is small increases the bending moment acting on the axle case 15. Can be small. That is, a lighter and cheaper axle case 15 can be used.

  For example, in a double tire structure in which two 265 / 70R19.5 tires are attached to one axle of an axle having a shaft weight of 7.5 tons, the total width of the two tires is about 575 mm. On the other hand, in the case of a single tire structure in which one tire of 445 / 45R19.5 is attached to one axle, the width of the tire is 445 mm, and the width of the wheel 43 is reduced by about 130 mm compared to the double tire structure. If the distance (vehicle width) between the left and right wheels is the same, in this embodiment, the distance between the centers of the wheels 43 is increased by about 130 mm. However, the air spring 18 is moved to the side member 12 without changing the distance between the side members 42. Since the distance W3 between the centers of the left and right air springs 18 is increased by about 300 mm. Therefore, the distance W2 between the tread and the center of the air spring is reduced by (300−130) / 2 = 85 mm, and the bending moment acting on the axle case 15 can be reduced by about 20%.

  Further, in the present embodiment, the space between the pair of side members 12 is not narrowed to form a space for arranging the air spring 18, but the width of the wheel 43 is narrowed to form the air spring 18. Since a space for placement is formed, a conventional vehicle frame can be used, and the cost can be reduced.

  Furthermore, in the present embodiment, the air spring 18 is disposed completely outside the side member 12 (between the wheel 43 and the side member 42 in the vehicle width direction) without changing the interval between the side members 42. The distance between the left and right air springs 18 can be increased by about 40% with respect to the previous embodiment. Therefore, the roll spring constant proportional to the product of the distance between the left and right air springs 18 and the spring constant is also increased, and the stabilizer 29 can be omitted or reduced in size (light weight and low cost).

  Moreover, the weight and cost of the wheel 43 can be reduced by configuring each wheel 43 with one single tire. Further, by configuring each wheel 43 with a single wide single tire, the width of the entire wheel is reduced, rolling friction loss during running can be reduced, and tire noise (noise) can be reduced, and fuel consumption can be improved. .

  As described above, the embodiment of the present invention is not limited to the above-described embodiment.

1 is a perspective view showing a preferred embodiment of an axle unit structure for an air suspension according to the present invention. It is a top view which shows the axle unit structure for air suspensions of FIG. FIG. 2 is a rear front view showing the air suspension axle unit structure of FIG. 1. It is the perspective view which abbreviate | omitted the wheel of FIG. It is the top view which abbreviate | omitted the wheel of FIG. FIG. 2 is a side view of the air suspension axle unit structure of FIG. 1 with wheels omitted. It is a perspective view which shows another suitable embodiment of the axle unit structure for air suspensions. It is a top view which shows the axle unit structure for air suspensions of FIG. FIG. 8 is a rear front view showing the air suspension axle unit structure of FIG. 7. FIG. 10A is a rear front view of the air suspension axle unit structure of FIG. 3 and FIG. 10B is of FIG. It is a perspective view which shows an example of the conventional axle unit. It is a top view which shows the other example of the conventional axle unit. It is a figure which shows the further another example of the conventional axle unit, Fig.13 (a) is the back front view, FIG.13 (b) is the side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Car body 11 Car frame 12 Side member 15 Axle case 17 Wheel 18 Air spring 19 Spring receiver 24, 26 Torque rod 41 Car frame 42 Side member 43 Wheel

Claims (3)

A vehicle frame having a pair of side members extending in the longitudinal direction of the vehicle body, an axle case supported on the vehicle frame via a torque rod and containing a rigid axle, and an axle case provided between the axle case and the side member And an air suspension axle unit structure comprising an air spring for reducing the vertical impact between the vehicle frame and the vehicle frame,
A pair of the air springs are arranged at positions outside the side members in the vehicle width direction and sandwiching the axle case close to the front and rear,
The pair of air springs are respectively fixed to the outer lateral surfaces of the side members in the vehicle width direction, and on the other hand, spring receivers are provided on the upper surface of the axle case so as to extend forward and backward to receive the pair of air springs from below. An axle unit structure for an air suspension, characterized in that the pair of air springs are connected to an axle case via a hub.   The wheel provided at both ends of the axle is a double tire, and a space between the pair of side members where the axle case is located is formed narrow to form a space for arranging the air spring. Axle unit structure for air suspension.   The wheels provided at both ends of the axle are single tires each having a width that is wide enough to have the same allowable load as that of a double tire and narrow enough to form a space for arranging the air spring. Axle unit structure for air suspension as described.

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