JP2018103764A - Leaf spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leaf spring suppressing abnormal sound caused by contact between leaf springs and thereby unnecessitating maintenance relating to the suppression of the abnormal sound to enable a cost reduction.SOLUTION: A leaf spring (5) is provided for suspending an axle body (4), which is supporting wheels (3) of a vehicle (1) at both ends, with respect to a vehicle body of the vehicle. The leaf spring is provided with a cylindrical opening end portion (11c) wound into a cylindrical shape at least at one end of the leaf spring. The leaf spring includes: a first leaf spring (11) to be attached to the vehicle body; and a second leaf spring (12) whose at least one part is in contact with the opening end portion of the first leaf spring, and including a constricted portion (12d) where a width in the vehicle width direction in the at least one part is smaller than a width in the vehicle width direction in the opening end portion of the first leaf spring. In the constricted portion of the second leaf spring, edge portions of a contact surface in contact with the first leaf spring are chamfered.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a leaf spring that suspends an axle body on a vehicle body.

  In a commercial vehicle such as a truck, a vehicle suspension device is mounted that suspends an axle body that supports wheels at both ends thereof, such as an ASKUL beam or an ASKUL housing. As an example of the vehicle suspension device, a leaf spring structure using a leaf spring has been conventionally used.

  In such a leaf spring, a first leaf spring formed with a cylindrical opening end portion (hereinafter also referred to as an eyeball portion) to be connected to the vehicle body side by winding both end portions thereof, 2. Description of the Related Art A leaf spring structure including a second leaf spring that is disposed on a leaf spring and covers a lower portion of the eyeball portion is known. Such a spring structure is disclosed in Patent Document 1, for example. In particular, in the spring structure of the vehicle suspension device disclosed in Patent Document 1, in order to prevent interference with the peripheral bracket, the width of both ends of the second leaf spring is smaller than the width of the first leaf spring. Yes. That is, both ends of the second leaf spring portion are narrowed.

  On the other hand, in the plate spring structure as described above, when the axle body is used for suspension on the vehicle body, rotational vibration in the extending direction may occur in the second plate spring. In such a case, there is a problem that the corners of both narrowed ends (hereinafter also referred to as narrowed portions) of the second leaf spring come into contact with the first leaf spring, and abnormal noise is generated. For example, Patent Document 2 discloses that a silencer such as a resin is provided at a contact portion between the first plate spring and the second plate spring to solve such a problem.

Japanese Utility Model Publication No. 64-39113 Japanese Utility Model Publication No. 63-173532

  However, if the silencer as described above is provided, the cost of the leaf spring itself increases and the durability of the silencer increases, which causes an increase in maintenance costs such as replacement of the silencer.

  The present invention has been made in order to solve such a problem, and the object of the present invention is to reduce the cost by suppressing the noise associated with the contact between the leaf springs and eliminating the need for maintenance related to the noise suppression. An object of the present invention is to provide a leaf spring capable of achieving the above.

  (1) A leaf spring according to this application example is a leaf spring that suspends an axle body that supports a vehicle wheel at both ends from a vehicle body of the vehicle, and has a cylindrical shape with at least one end wound in a cylindrical shape. A first leaf spring attached to the vehicle body, and at least a part of the first leaf spring is in contact with the opening end of the first leaf spring, and the width in the vehicle width direction of the at least part is A second leaf spring having a narrowed portion smaller than a width in the vehicle width direction at the opening end portion of the first leaf spring, and in the narrowed portion of the second leaf spring, the first leaf spring and The edge of the contact surface that contacts is chamfered.

  In the leaf spring according to this application example, the edge of the narrowed portion of the second leaf spring is chamfered, so that even if rotational vibration in the extending direction occurs with respect to the second leaf spring, The edge portion of the constriction portion does not come into contact with the first leaf spring. For this reason, the noise which arises when the edge part of the constriction part of a 2nd leaf | plate spring contacts with respect to a 1st leaf | plate spring is prevented. Moreover, since the contact of the edge part of the constriction part of the 2nd leaf | plate spring with respect to a 1st leaf | plate spring is prevented, installation of the silencer and its maintenance become unnecessary, and it can aim at the cost reduction of leaf spring itself.

  (2) In the leaf spring according to this application example, in the above (1), the second leaf spring is partially separated from the first leaf spring from one end to the other end where the opening end is formed. It is separated. Accordingly, it is possible to prevent the edge portion of the narrowed portion of the second leaf spring from coming into contact with the first leaf spring while enhancing the impact relaxation characteristics of the leaf spring.

  (3) In the leaf spring according to this application example, in the above (1) or (2), the opening end may have a Berlin-type shape. As a result, even in the case of the Berlin type in which vibration due to contact between both leaf springs is likely to resonate, the edge of the narrowed portion of the second leaf spring does not contact the first leaf spring, thereby preventing abnormal noise. be able to.

  (4) The leaf spring according to this application example further includes a third leaf spring that cooperates with the first leaf spring and sandwiches the second leaf spring in any one of the above (1) to (3), The narrowed portion of the second leaf spring may be smaller than the width in the vehicle width direction at the end of the third leaf spring, and the edge of the contact surface that contacts the third leaf spring may be chamfered. In other words, in addition to preventing the edge of the narrowed portion of the second leaf spring from contacting the first leaf spring, the edge of the narrowed portion of the second leaf spring is in contact with the third leaf spring. Contact is also prevented. As a result, even when the leaf springs are stacked in multiple layers, contact that causes abnormal noise between the leaf springs facing each other can be prevented, and the cost of the leaf spring itself can be reduced.

  According to the present invention having the above-described structure, it is possible to reduce the cost by suppressing the noise associated with the contact between the leaf springs and eliminating the need for maintenance related to the suppression of the noise.

1 is a schematic partial perspective view of a vehicle on which a leaf spring according to an embodiment of the present invention is mounted. It is a side view of the leaf spring concerning one embodiment of the present invention. FIG. 3 is an enlarged view of a region III surrounded by a solid line in FIG. 2. FIG. 4 is a partially enlarged cross-sectional view of the leaf spring taken along line IV-IV in FIG. 3. FIG. 4 is an enlarged side view of the up-turn leaf spring shown in FIG. 3. It is a partial expanded sectional view of the leaf spring which shows similarly to FIG. 4 and which concerns on the modification of this invention. It is a partial expanded sectional view of the leaf spring which shows the same as FIG. 4 and which concerns on the further modification of this invention.

  Hereinafter, a leaf spring according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Here, FIG. 1 is a schematic partial perspective view of a vehicle equipped with a leaf spring according to the present embodiment. FIG. 2 is a side view of the leaf spring according to the present embodiment. 3 is an enlarged view of a region III surrounded by a solid line in FIG. 4 is a partial enlarged cross-sectional view of the leaf spring taken along line IV-IV in FIG.

  As shown in FIG. 1, in a vehicle 1, two frames 2 that are a part of a vehicle body, a plurality of wheels 3, a plurality of axle bodies 4 that support the wheels 3 at both ends, and an axle body with respect to the frame 2. A plurality of leaf springs 5 are suspended. In each of the leaf springs 5, one end (an opening end portion to be described later) is connected to the frame 2 via a bracket 6, and the other end is connected via an air spring system 7 and an attachment member 8 of the air spring system 7. Connected to frame 2. A shock absorber 9 is provided between the frame 2 and the axle body 4 and in the vicinity of the air spring system 7. For convenience of explanation and drawings, only one wheel 3 and one axle body 4 are shown in FIG.

  Such a connection configuration around the wheel 3 enables the wheel 3 to move relative to the frame 2 in the vertical direction, and when the vehicle 1 travels on the uneven road, the shock and vibration from the uneven road are the frame. 2 is prevented from being transmitted. As a result, the riding comfort and handling stability of the vehicle 1 are improved.

  Next, as shown in FIG. 2, the leaf spring 5 includes a first leaf spring 11 that is generally referred to as a parent spring, and a second leaf spring 12 that is also generally referred to as a child spring. Further, the leaf spring 5 has a fixing member 13 for fixing the first plate spring 11 and the second plate spring 12. Here, the fixing member 13 includes a flat plate 14 disposed on the first surface 11 a of the first plate spring 11, a first plate spring 11, a second plate spring 12, a bolt 15 passing through the flat plate 14, And a nut 16 disposed on the first surface 12 a of the two leaf springs 12. Due to such a configuration, the leaf spring 5 has a structure in which a part of the second surface 11b of the first leaf spring 11 and a part of the second surface 12b of the second leaf spring 12 are in contact with each other. doing. When the leaf spring 5 is attached to the frame 2, the first leaf spring 11 is located above (that is, the frame 2 side), and the second leaf spring 12 is located below (ie, the ground side).

  As shown in FIG. 2, the first plate spring 11 is a plate-like member having a shape in which the central portion protrudes upward (that is, the higher side in the vehicle height direction). As shown in FIGS. 2 and 3, the first leaf spring 11 includes an opening end portion 11 c that is wound in a cylindrical shape and formed in a cylindrical shape at one end thereof (front side in the front-rear direction of the vehicle). . On the other hand, the other end of the first leaf spring 11 (the rear side in the front-rear direction of the vehicle) is not wound, and the other end has a flat plate shape. That is, the leaf spring 5 according to the present embodiment has an eyeball portion (open end portion 11c) formed only at one end. In the opening of the opening end portion 11 c of the first plate spring 11, a cylindrical rubber 17 for absorbing shock and a cylindrical metal for enabling the first plate spring 11 to be attached to the bracket 6. The body 18 is fitted. By providing the rubber 17 as described above, various impacts can be absorbed.

  Further, at the end of the first leaf spring 11 where the opening end 11c is located, the first leaf spring 11 is bent so as to be lowered one step in the stacking direction of the first leaf spring 11 and the second leaf spring 12. It is rolled up. That is, in the present embodiment, the opening end portion 11c has a Berlin-type shape.

  As shown in FIG. 2, the second leaf spring 12 is shorter than the first leaf spring 11 and is provided so as to cover a part of the second surface 11 b of the first leaf spring 11. More specifically, the second leaf spring 12 has a curved end portion 12c formed in a substantially cylindrical shape so as to surround the outside of the opening end portion 11c of the first leaf spring 11 (one front side of the vehicle in the front-rear direction). ) On the other hand, the other end of the second leaf spring 12 (the rear side in the front-rear direction of the vehicle) is not wound, the shape of the other end is flat, and the other end is near the center of the first leaf spring 11. Touching. Further, the second leaf spring 12 projects upward from the central portion to the other end, and the shape of the projecting portion of the second leaf spring 12 is that of the projecting portion of the center portion of the first leaf spring 11. It corresponds to the shape.

  The second surface 12 b of the second leaf spring 12 is not completely in contact with the second surface 11 b of the first leaf spring 11. More specifically, the curved end portion 12c of the second leaf spring 12 is in contact with only the lowermost portion of the opening end portion 11c with respect to the opening end portion 11c of the first leaf spring 11. Yes. Further, the second leaf spring 12 extends from the first leaf spring 11 from the contact portion between the opening end portion 11c of the first leaf spring 11 and the curved end portion 12c of the second leaf spring 12 toward the center portion of both leaf springs. A gap 21 is formed apart. Further, the second leaf spring 12 is separated from the first leaf spring 11 from the contact surface between the projecting center portion of the first leaf spring 11 and the projected portion of the second leaf spring 12 toward the other end of both leaf springs. The gap 22 is formed. In other words, the second leaf spring 12 is partially separated from the first leaf spring 11 from one end to the other end where the opening end portion 11c is formed. In addition, the formation of such gaps 21 and 22 can enhance the impact relaxation characteristics of the leaf spring 5 itself.

  Here, as can be seen from FIGS. 3 and 4, the second plate in which a portion of the curved end portion 12 c of the second leaf spring 12 is in contact with a portion of the opening end portion 11 c of the first leaf spring 11. In the contact portion of the spring 12 and the vicinity thereof, the width of the second plate spring 12 in the vehicle width direction is smaller than the width of the first plate spring 11 in the vehicle width direction. That is, the 2nd leaf | plate spring 12 has the constriction part 12d in the said contact part which is an area | region where hatching was given in FIG. 3, and its vicinity area | region. As shown in FIG. 4, in the narrowed portion 12 d of the second leaf spring 12, chamfering is performed on the edge portion of the contact surface that contacts the first leaf spring 11 of the second leaf spring 12. More specifically, the edge portion of the second leaf spring 12 is subjected to R-surface processing and is curved.

  By chamfering the edge portion of the constricted portion 12d, the edge portion of the constricted portion 12d of the second leaf spring 12 can be moved even if rotational vibration in the extending direction occurs with respect to the second leaf spring 12. The contact with the one leaf spring 11 is eliminated, and the generation of abnormal noise is prevented. Here, in a general Berlin-type leaf spring, when the edge of the narrowed portion of the second leaf spring comes into contact with the first leaf spring, the vibration accompanying the contact causes the gap 21 in the present embodiment. Resonance occurs in the vicinity of the gap between the first leaf spring and the second leaf spring corresponding to the above, and a large noise is generated. Therefore, a relatively large silencer for preventing such a large noise is provided. I need it. However, in the present embodiment, the contact of the edge of the narrowed portion 12d with the first leaf spring 11 is prevented, so that it is not necessary to install a silencer and its maintenance, and the cost of the leaf spring 5 itself can be reduced. it can.

  In the embodiment described above, the narrowed portion 12d chamfered on only a part of the curved end portion 12c of the second leaf spring 12 is formed, but the curved end portion 12c itself also functions as the narrowed portion 12d. The entire side portion of the curved end portion 12c may be chamfered while being narrowed.

  Further, the leaf spring according to the present embodiment may be applied to an up-turn type leaf spring, for example, as shown in FIG. Here, FIG. 5 is an enlarged side view of the up-turn type leaf spring shown in the same manner as FIG. In FIG. 5, the same members as those in FIG. 3 are denoted by the same reference numerals, and the description thereof is omitted below.

  As shown in FIG. 5, in the up-turn leaf spring 5 ′, one end of the first leaf spring 11 ′ is wound to form an open end portion 11c ′, but the first leaf spring 11 ′ is the first one. It curves so that it may raise in the lamination direction (vehicle height direction) of 1 leaf | plate spring 11 'and 2nd leaf | plate spring 12'. That is, in the up-turn type leaf spring 5 ′, the opening end portion 11 c ′ has an up-turn type shape.

  Here, in the general up-turn type leaf spring, the gap formed by separating the first plate spring and the second plate spring is small compared to a general Berlin-type leaf spring. Resonance in the gap is unlikely to occur, and generation of abnormal noise is suppressed. However, even in such an up-turn type, a slight noise is generated, but also in such a leaf spring 5 ′, a narrowed portion 12d chamfered on the curved end portion 12c ′ of the second leaf spring 12 ′. By providing ', the edge portion of the narrowed portion 12d' of the second leaf spring 12 does not come into contact with the first leaf spring 11 ', and the generation of the noise can be prevented.

  In the above-described embodiment, the edge of the constricted portion 12d of the second leaf spring 12 has been subjected to R-surface machining as chamfering. However, the edge of the constricted portion 12d of the second leaf spring 12 is used. However, other chamfering processing may be used as long as it can be prevented from coming into contact with the first leaf spring 11. For example, as shown in FIG. 6, a C-plane process may be performed on the narrowed portion 12d 'of the second leaf spring 12'. Here, FIG. 6 is an enlarged cross-sectional view of a leaf spring according to a modification of the present invention shown in the same manner as FIG.

  Even in such a chamfering process, the edge portion of the narrowed portion 12d ′ of the second leaf spring 12 does not come into contact with the first leaf spring 11 ′, and an abnormal noise due to the contact and vibration of both leaf springs is eliminated. Can be prevented.

  Further, the leaf spring 5 is formed from two leaf springs, but a desired leaf spring may be formed by stacking three or more leaf springs. Even in such a case, a chamfered constricted portion is provided in a portion where an edge of one leaf spring and another leaf spring come into contact with each other to generate an abnormal noise. For example, it is good also as a form of the further modification as shown in FIG. Here, FIG. 7 is a partially enlarged cross-sectional view of a leaf spring according to a further modification of the present invention, which is shown in the same manner as FIG.

  As shown in FIG. 7, a leaf spring 5 ″ according to a further modification includes a third leaf spring 31 in addition to the first leaf spring 11 and the second leaf spring 12 ″. Here, the third leaf spring 31 sandwiches the second leaf spring 12 ″ in cooperation with the first leaf spring 11. That is, the leaf spring 5 ″ according to the modified example has a structure in which the first plate spring 11, the second plate spring 12 ″, and the third plate spring 31 are sequentially stacked.

  Further, the narrowed portion 12 d ″ of the second leaf spring 12 ″ is formed to be smaller than the width in the vehicle width direction at the end portion of the third leaf spring 31. Further, the narrowed portion 12d ″ of the second leaf spring 12 ″ is chamfered not only on the contact surface side with the first leaf spring 11 but also on the contact surface side with the third leaf spring 31. Yes.

  In the leaf spring 5 ″ according to such a further modification, the edge of the narrowed portion 12d ″ of the second leaf spring 12 ″ is prevented from coming into contact with the first leaf spring 11. In addition, the edge of the narrowed portion 12d ″ of the second leaf spring 12 ″ is prevented from contacting the third leaf spring 31. Therefore, even when the leaf springs are stacked in multiple layers, contact that causes abnormal noise between the leaf springs facing each other can be prevented, and the cost of the leaf spring itself can be reduced.

  In the above-described embodiment, the opening end portion 11 c is formed only at one end portion of the first plate spring 11, but the opening end portion 11 c is formed at both ends of the first plate spring 11 by winding both ends. It may be formed. In such a case, the second leaf spring 12 is also formed with curved end portions 12c and chamfered narrow portions 12d at both ends.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Frame 3 Wheel 4 Axle body 5, 5 ', 5''Leaf spring 6 Bracket 7 Air spring system 8 Mounting member 8
9 Shock absorber 11, 11 ′ First leaf spring 11a First surface 11b Second surface 11c, 11c ′ Open end portion 12, 12 ′, 12 ″ Second leaf spring 12a First surface 12b Second surface 12c, 12c ′ Curved ends 12d, 12d ', 12d''Narrowed portion 13 Fixing member 14 Flat plate 15 Bolt 16 Nut 17 Rubber 18 Metal body 21, 22 Gap 31 Third leaf spring

Claims (4)

A leaf spring that suspends an axle body that supports a vehicle wheel at both ends with respect to the vehicle body of the vehicle,
A first leaf spring that includes a cylindrical opening end portion, at least one end of which is wound in a cylindrical shape, and is attached to the vehicle body;
At least a part contacts the opening end of the first leaf spring, and the width in the vehicle width direction of the at least part is smaller than the width of the opening end of the first leaf spring in the vehicle width direction. A second leaf spring having a constriction,
In the narrowed portion of the second leaf spring, a leaf spring in which an edge portion of a contact surface in contact with the first leaf spring is chamfered.   The leaf spring according to claim 1, wherein the second leaf spring is partially separated from the first leaf spring from one end to the other end where the opening end is formed.   The leaf spring according to claim 1 or 2, wherein the opening end has a Berlin-type shape. And further comprising a third leaf spring that sandwiches the second leaf spring in cooperation with the first leaf spring,
The narrowed portion of the second leaf spring is smaller than the width in the vehicle width direction at the end of the third leaf spring, and the edge portion of the contact surface that contacts the third leaf spring is chamfered. The leaf spring according to any one of 3 above.

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