JP6645066B2 - Leaf spring suspension system - Google Patents

Description

  The present invention relates to an improvement of a leaf spring type suspension device.

  2. Description of the Related Art Various types of suspension devices for vehicles have been known. Among such suspension systems of various structures, the so-called leaf spring type vehicle suspension system has a simple and robust structure and can be manufactured at a lower cost than suspension systems of other structures. , Buses and other large transport vehicles, and light commercial vehicles (light trucks, vans, etc.).

FIG. 5 shows an example of a conventional structure of the leaf spring type suspension device 1 described in Patent Document 1. The leaf spring type suspension device 1 includes a leaf spring 2 formed by stacking a plurality of leaf springs, and an axle support 3.
The leaf spring 2 is provided with a pair of annular support rings 4a and 4b at both ends in the front-rear direction (the left-right direction in FIG. 5 and the front-rear direction of the vehicle body).
The axle support portion 3 is for supporting the axle 5, and is constituted by a U-shaped bolt supported and fixed to the center of the leaf spring 2 in the front-rear direction.

  Further, a front spring bracket 7 is fixed to a portion of the body frame 6 on which the leaf spring type suspension device 1 as described above is assembled in front of the axle 5. On the other hand, a rear spring bracket 9 is fixed to a portion of the vehicle body frame 6 behind the axle 5. A shackle 10 is supported on the rear spring bracket 9 by a support pin 17 so as to be swingable.

  With respect to the vehicle body frame 6 as described above, the front end portion of the leaf spring type suspension device 1 (the support ring portion 4a provided on the front side of the support ring portions 4a and 4b) is attached to the front spring bracket 7 , And is swingably supported by a swing pin 8. The rear end of the leaf spring suspension device 1 (the support ring 4b provided on the rear side of the two support rings 4a and 4b) is connected to the rear spring bracket 9 of the shackle 10. Is supported by a swing pin 11 at an end opposite to that supported by the swing pin. The axle 5 is inserted inside the axle support 3.

  In this way, the rear end of the leaf spring 2 (the support ring 4b) is supported by the shackle 10 so as to be capable of being displaced in the front-rear direction (oscillation displacement) with respect to the vehicle body frame 6, thereby enabling the leaf The leaf spring 2 is allowed to bend (elastically deform) when a load is applied to the spring 2 so that vibrations and impacts that the axle 5 receives from the road surface during traveling are not transmitted directly to the vehicle body frame 6. ing.

  By the way, the load weight of a vehicle is specified. If the vehicle is operated in a state where the load is exceeded (overloaded state), the mobility of the vehicle may be reduced, which may cause an accident. Further, if the operation is continued in an overloaded state, the road surface is severely damaged, and the cost of road maintenance may increase. Such an overloaded state may be caused by the driver not being able to grasp the actual load amount, and a means for notifying the driver of the overloaded state is required.

JP 2001-113926 A

  The present invention has been made in view of the above-described circumstances, and has been made to realize a structure capable of notifying a driver of a situation of overloading.

The leaf spring type suspension device of the present invention includes a leaf spring, an axle support, a conversion mechanism, and a displacement measuring unit.
The leaf spring is configured by a leaf spring that can be flexibly deformed. In such a leaf spring, one end in the front-rear direction is supported so as to be swingable with respect to the vehicle body, and the other end in the front-rear direction is displaceable and swingable in the front-rear direction with respect to the vehicle body. Supported.
The axle support portion is for supporting an axle, and is provided at an intermediate portion of the leaf spring in the front-rear direction.
The conversion mechanism includes a ball nut which is linearly moving member, a ball screw mechanism which have a ball screw shaft which is a rotating member, connected directly or via a shackle with respect to the longitudinal direction end portion of the leaf spring are caused by the vertical distance between the said vehicle body and said axle is changed, the linear motion of the ball nut with the longitudinal direction displacement of the longitudinal other end of the leaf spring, said ball screw shaft It is for converting into rotary motion .
The displacement measuring means is for measuring a displacement amount of a member constituting the conversion mechanism (for example, a rotation angle of the ball screw shaft , an axial displacement amount of the ball nut , and the like). Incidentally, the measurement by the displacement measuring means may be configured not only to directly measure the displacement amount of the member constituting the conversion mechanism, but also indirectly through another member fixed to the member.

Further, the leaf spring type suspension apparatus of the present invention, the ball screw shaft connects the motor generator for converting the rotational motion of the ball screw shaft to power.
The motor generator is a generator that converts the rotational movement of the ball screw shaft accompanying the linear movement of the ball nut into electric power based on a change in the amount of deflection of the leaf spring caused by the vertical movement of the vehicle body. A function as an electric motor that adjusts the height of the vehicle body by linearly moving the ball nut by rotating the ball screw shaft based on energization and changing the amount of deflection of the leaf spring. Having.
In practicing the present invention, the ball screw shaft is disposed with the center axis thereof oriented in the front-rear direction, supported so as to be able to rotate only with respect to the vehicle body, and the ball nut is mounted on the leaf spring. Can be connected directly or via a shackle to the other end in the front-rear direction so that the circumference of the ball screw shaft can be displaced in the front-rear direction.

According to the leaf spring type suspension device of the present invention configured as described above, it is possible to realize a structure capable of notifying a driver of an overloaded situation.
That is, the leaf spring type suspension device of the present invention uses the linear motion of the ball nut , which is a linear member , in accordance with the displacement of the other end of the leaf spring in the front-rear direction with respect to the vehicle body, by rotating the ball screw shaft , which is a rotating member. There is provided a conversion mechanism for converting into motion, and a displacement amount measuring means for measuring a displacement amount of a member constituting the conversion mechanism. For this reason, the amount of deflection of the leaf spring (the amount of displacement of the other end of the leaf spring in the front-rear direction) according to the load of the vehicle can be measured as the amount of displacement of the member constituting the conversion mechanism. . If the load amount is measured based on such a measurement result, a system for notifying the driver of the load amount of the vehicle can be easily constructed.

1A is a schematic diagram of a leaf spring type suspension device according to a first embodiment of the present invention, and is a schematic diagram illustrating a state in which a vehicle has a small payload, and a schematic diagram illustrating a state in which a vehicle has a large payload. (B). The figure similar to FIG. 1 which shows an example of the reference example of this invention. The figure similar to FIG. 1 which shows the 2nd example of embodiment of this invention. FIG. 2 is a view similar to FIG. 1, showing a structure in which a guide member is added. The figure which shows an example of the conventional structure of a leaf spring type suspension device.

[First Example of Embodiment]
A first example of an embodiment of the present invention will be described with reference to FIG. The leaf spring type suspension device 1a of this example is used by being incorporated in a vehicle such as a large transport vehicle such as a truck or a bus, or a light commercial vehicle (for example, a light truck or van). FIG. 1 schematically shows a state in which a leaf spring type suspension device 1a of the present embodiment is incorporated in the vehicle.
Such a leaf spring type suspension apparatus 1a of the present embodiment includes a shackle 10a, a leaf spring 2a, an axle support section 3a, a ball screw mechanism 12, and a rotation angle measuring means including a rotation angle sensor such as an encoder. (Not shown) and a motor generator 13.

  The shackle 10a is a substantially oval plate-like member, and has a circular shape penetrating in a thickness direction of the shackle 10a (a front-back direction in FIG. 1) at a portion closer to one end in the longitudinal direction (the lower end in FIG. 1). The first through hole 14 is formed. Further, a circular second through hole 15 is formed at a position shifted from the central portion in the longitudinal direction of the shackle 10a to one side in the longitudinal direction, and penetrates in the thickness direction of the shackle 10a. Further, a third through hole 16 having an oval shape that penetrates in the thickness direction of the shackle 10a and is long in the longitudinal direction of the shackle 10a is formed in a portion near the other longitudinal end (the upper end in FIG. 1) of the shackle 10a. Have been.

  The shackle 10a having the above-described configuration is provided in the second through hole 15 with respect to the rear spring bracket 9a fixed to a portion of the body frame 6 behind the axle 5 (for example, the rear axle). It is swingably supported by the inserted support pin 17.

  The leaf spring 2a is configured by stacking a plurality of flexibly deformable leaf springs in the vertical direction. The leaf spring 2a is provided with a pair of annular support rings 4a, 4b at both ends in the front-rear direction (the left-right direction in FIG. 1 indicates the front-rear direction of the vehicle body). In the structure of the illustrated leaf spring 2a, a plurality of leaf springs constituting the leaf spring 2a are omitted. The structure of the leaf spring 2a is substantially the same as the structure of the leaf spring 2 provided in the leaf spring type suspension device of one example of the conventional structure described above.

In the leaf spring 2a having the above-described configuration, the front end portion (the support ring portion 4a disposed on the front side of the two support ring portions 4a and 4b) has a greater height than the axle 5 in the body frame 6. A front spring bracket 7a fixed to the front portion is swingably supported by a swing pin 8a.
On the other hand, the rear end portion of the leaf spring 2a (the support ring portion 4b disposed on the rear side of the support ring portions 4a and 4b) is provided with a swing pin 11a in the first through hole 14 of the shackle 10a. , So that it is swingably supported.

  The axle support portion 3a is for supporting the axle 5, and is constituted by a U-shaped bolt supported at the center in the front-rear direction of the leaf spring 2a. The axle 5 is supported inside such an axle support 3a. In this state, at least the uppermost leaf spring of the plurality of leaf springs constituting the leaf spring 2 and the axle 5 can be relatively displaced in the front-rear direction. It is also possible to adopt a configuration in which the axle support portion 3a is provided at a position shifted in the front-rear direction from the center portion in the front-rear direction of the leaf spring 2a.

The ball screw mechanism 12 is a conversion mechanism described in the claims, and includes a ball screw shaft 18, a ball nut 19, a plurality of balls (not shown), and a ball circulation device.
The ball screw shaft 18 corresponds to the rotating member described in the claims, and has a ball screw groove formed on the outer peripheral surface.
The ball nut 19 has a ball screw groove formed on the inner peripheral surface. A nut-side projection 20 protruding outward is formed on a part of the outer peripheral surface of the ball nut 19. Such a nut side projection 20 is inserted inside the third through hole 16 of the shackle 10a in an assembled state. Thus, the rear end of the leaf spring 2a and the ball nut 19 are connected via another member (the shackle 10a). The ball nut 19 is externally fitted to the ball screw shaft 18 so that only the axial displacement of the ball screw shaft 18 (the left-right direction in FIG. 1) is possible.
Each of the balls is rotatably provided in a spiral space formed between the two ball screw grooves.
The ball circulation device is for circulating the balls in the spiral space.

  Both ends of the ball screw shaft 18 in the axial direction are supported by a part of the vehicle body frame 6 by a pair of rolling bearings 21 so as to be rotatable with respect to the vehicle body frame 6.

  In the case of the present example having the above-described configuration, when the shackle 10a swings around the support pin 17, the swinging movement is caused by the ball of the ball nut 19 through the nut-side protrusion 20. It is converted into a linear motion of the screw shaft 18 in the axial direction. Then, the ball screw shaft 18 is further driven to rotate with the linear motion. The relationship between the amount of swing displacement of the shackle 10a and the rotation angle (the amount of rotation) of the ball screw shaft 18 depends on the configuration of the ball screw groove of the ball screw shaft 18 (the ball screw groove of the ball nut 19). It can be set by setting (lead) as appropriate. That is, by appropriately setting the configuration of the ball screw groove of the ball screw shaft 18 (the ball screw groove of the ball nut 19), the rotation angle of the ball screw shaft 18 becomes larger than the swing angle of the shackle 10a. (The swing angle of the shackle 10a can be amplified). The distance between the center of the second through hole 15 and the center of the nut-side protrusion 20 in the assembled state (initial state) shown in FIG. If a configuration in which the distance from the center of the through hole 15 is larger is adopted, the displacement amount of the ball nut 19 (nut side convex portion 20) is changed by the swing displacement amount (the longitudinal displacement) of the first through hole 14 portion. Volume) can be amplified.

  The rotation angle measurement means is a displacement amount measurement means described in the claims, and the rotation angle of the ball screw shaft 18 when the ball screw shaft 18 rotates with the swing of the shackle 10a. It is provided for measuring. As such a rotation angle measuring means, for example, one having a structure including an optical or magnetic encoder and a sensor can be adopted. Further, the rotation angle measuring means may use a rotation detection sensor in which the motor generator 13 is incorporated. When this configuration is adopted, the rotation angle of the ball screw shaft 18 can be indirectly measured as the rotation angle of the rotation shaft 22 of the motor generator 13 coupled to the ball screw shaft 18.

  The motor generator 13 has a function as an electric motor (electric motor) and a function as a generator, and the rotating shaft 22 of the motor generator 13 is provided at one end of the ball screw shaft 18 in the axial direction. (The left end in FIG. 1) in a state of being connected via a joint or the like. The arrangement of the motor generator 13 is not limited to the illustrated case. By providing another member (gear, chain, belt) or the like between the motor generator 13 and the ball screw shaft 18, the center axis of the rotation shaft 22 of the motor generator 13 and the ball screw The center axis of the shaft 18 can be offset.

Such a motor generator 13 converts (generates) mechanical energy (rotational motion) input to the rotating shaft 22 into electric energy by the function as the generator, and generates the electric energy through an inverter (not shown). The secondary battery (not shown) can be charged. In the case of this example, the rotational motion of the ball screw shaft 18 is input and the rotational motion is converted into electric energy.
On the other hand, the motor generator 13 converts electric energy supplied from the secondary battery into mechanical energy (rotational motion) by a function as an electric motor (electric motor), and also drives the rotary shaft 22 to rotate. it can. In the case of this example, when the rotation shaft 22 is rotationally driven by the function as the electric motor, the ball screw shaft 18 is rotationally driven, and the ball nut 19 is displaced in the axial direction of the ball screw shaft 18. It is configured like this.

According to the leaf spring suspension device 1a of the present example having the above-described configuration, it is possible to realize a structure capable of notifying the driver of an overload situation (load amount).
Hereinafter, a method of measuring the load capacity of the vehicle using the leaf spring suspension device 1a of the present embodiment will be described.
FIG. 1A shows a state where only the weight of the vehicle body acts on the leaf spring 2a. The leaf spring 2a in this state is curved downward at a predetermined curvature in a convex arc shape. Further, the shackle 10a is arranged in a state where the longitudinal direction is located in the vertical direction (the vertical direction of the vehicle body). The ball nut 19 constituting the ball screw mechanism 12 is located on the other end side (the right side in FIG. 1) of the ball screw shaft 18 in the axial direction with respect to the axial center of the ball screw shaft 18. I have. The nut-side projection 20 of the ball nut 19 is located in a portion of the third through hole 16 of the shackle 10a closer to one longitudinal end (the lower end in FIG. 1) of the shackle 10a.

When a person or a load (hereinafter, referred to as a "load") is loaded on the vehicle body from the state shown in FIG. 1A, the leaf spring suspension device 1a is moved to the state shown in FIG. The state shown in FIG. In the state shown in FIG. 1B, the body frame 6 is displaced downward (in a direction closer to the road surface 23) than the state shown in FIG. 1A, but is displaced from the road surface 23 of the axle 5. Position (height) does not change, the vertical distance between the vehicle body frame 6 and the axle 5 decreases, and the leaf spring 2a increases the distance in the front-rear direction between both ends in the front-rear direction. The leaf spring 2a bends (resiliently deforms) so that the curvature of the leaf spring 2a becomes small. In this case, positions in the longitudinal direction of the front end of the leaf spring 2a is unchanged, relative to the front end the front spring bracket 7a, around the pivot shaft 8, an arrow alpha ₁ in FIG. 1 (b) Swings in the direction indicated by.

On the other hand, the position of the rear end of the leaf spring 2a in the front-rear direction is displaced rearward from the state shown in FIG. Specifically, the rear end portion of the leaf spring 2a, the shackle 10a is relative to the rear spring bracket 9a, rocking in the direction indicated by the arrow alpha ₂ in Fig. 1 (b) about said support pin 17 Along with it to dynamic, while swinging in the direction indicated by the arrow alpha ₃ in FIG. 1 (b) around the pivot shaft 11a relative to the shackle 10a, displaced backward.

Further, with the swing of the shackle 10a as described above, the nut-side projection 20 of the ball nut 19 moves through the third through hole 16 of the shackle 10a from the position shown in FIG. The shackle 10a is displaced toward the other longitudinal end (the upper end in FIG. 1). At this time, since the ball nut 19 is mounted on the ball screw shaft 18 in a state where only axial displacement is allowed (in a state where vertical displacement is prevented), the ball nut 19 is mounted. The ball nut 19 is displaced in the axial direction of the ball screw shaft 18 (to the left in FIG. 1). Then, the ball screw shaft 18 is rotationally driven with the axial displacement (linear movement) of the ball screw shaft 18 of the ball nut 19.
In the case of this example, the rotation angle of the ball screw shaft 18 is measured by the rotation angle measuring means. Then, based on the result of the measurement, an arithmetic unit (not shown) calculates the load amount of the load loaded on the vehicle body, and notifies the driver of the calculation result. The process of calculating the load amount from the rotation angle of the ball screw shaft 18 can be performed, for example, using a conversion map representing the relationship between the rotation angle and the load amount.

In the case of this example, the vehicle has a function of adjusting the height of the vehicle in accordance with the driver's instructions and road surface conditions. Such a function of adjusting the vehicle height utilizes a function of the motor generator 13 as an electric motor (electric motor). Specifically, in the case of this example, when the function as the electric motor (electric motor) is operated according to an instruction from a controller (not shown), the rotating shaft 22 and the ball screw shaft 18 are driven to rotate. Next, with the rotation of the ball screw shaft 18, the ball nut 19 is displaced in the axial direction of the ball screw shaft 18, and the shackle 10a swings. Then, with the swing of the shackle 10a, the position of the rear end of the leaf spring 2a in the front-rear direction changes. As a result, the amount of deflection (the amount of elastic deformation) of the leaf spring 2a changes, and the vehicle height can be adjusted. As a method of instructing the controller, a method of instructing the driver himself or a method of automatically determining and supporting the road surface condition can be adopted.
The motor torque, motor current, and the like of the motor generator 13 when the function of adjusting the vehicle height as described above is operated are measured, and based on the measurement result, the load loaded on the vehicle body is measured. It is also possible to adopt a configuration for calculating the load of objects.

  In the case of this example, it is also possible to generate electric power by the function of the motor generator 13 as a generator as the vehicle body moves up and down. Specifically, when the vehicle body frame 6 moves up and down during traveling, the amount of deflection (the amount of elastic deformation) of the leaf spring 2a changes, and the shackle 10a swings and displaces. When the ball nut 19 is displaced in the axial direction of the ball screw shaft 18 with the displacement of the shackle 10a, the ball screw shaft 18 is driven to rotate. Then, as the ball screw shaft 18 rotates, the rotation shaft 22 of the motor generator 13 is driven to rotate. In this way, the rotational motion input to the rotating shaft 22 is converted (electric power generation) into electric energy, and the electric energy is stored in the secondary battery via the inverter.

[Example of Reference Example]
An example of a reference example of the present invention will be described with reference to FIG. The leaf spring suspension device 1b of the present reference example is different from the first example of the above-described embodiment in the structure of the shackle 10b and the ball screw mechanism 12a. Hereinafter, the structures of the shackle 10b and the ball screw mechanism 12a will be described.

The shackle 10b of the leaf spring suspension device 1a according to the present embodiment includes a spring-side half 24, which is a substantially elliptical plate-like member, and a substantially oval-shaped vehicle body side longer than the spring-side half 24. A substantially boomerang-shaped (substantially rectangular shape) plate-shaped member in which the longitudinal ends of the half part 25 are connected to each other by a bent part 26.
Such a shackle 10b penetrates in a thickness direction of the shackle 10b (a front-back direction in FIG. 2) near a longitudinal one end (an end farther from the bent portion 26) of the spring-side half portion 24. A circular first through hole 14a is formed. The bent portion 26 is formed with a circular second through hole 15a penetrating in the thickness direction of the shackle 10b. Further, an oval third through hole 16a penetrating in the thickness direction of the shackle 10b is provided at a portion of the vehicle body side half 25 near the other end in the longitudinal direction (an end farther from the bending portion 26). Is formed.

The shackle 10b having the above-described configuration is supported on the rear spring bracket 9a by a support pin 17 inserted through the second through hole 15a so as to be able to swing around the support pin 17. ing.
Further, one end in the longitudinal direction of the spring side half portion 24 constituting the shackle 10b and the rear end portion (the support ring portion 4b) of the leaf spring 2a are pivotally inserted into the first through hole 14a of the shackle 10b. The pins 11a are connected so as to be swingable.

The ball screw mechanism 12a includes a ball screw shaft 18a, a ball nut 19a, a plurality of balls (not shown), and a ball circulation device.
The ball screw shaft 18a has a ball screw groove formed on the outer peripheral surface. A part of the outer peripheral surface of one end (lower end in FIG. 2) of the ball screw shaft 18a in the axial direction is formed with a screw shaft side protrusion 27 protruding outward. Such a screw shaft side convex portion 27 is, for example, formed in a state of being bent from one axial end of the ball screw shaft 18a in a direction perpendicular to the direction of the center axis of the ball screw shaft 18a. Can do things.
The ball nut 19a corresponds to a rotating member, and has a ball screw groove formed on an inner peripheral surface. Such a ball nut 19a is externally fitted to the ball screw shaft 18a so as to be able to rotate only relative to the ball screw shaft 18a. For this reason, in the case of the present embodiment, the ball nut 19a is supported by a bearing (not shown) with respect to the vehicle body frame 6 so as to be capable of relative rotation.
Each of the balls is rotatably provided in a spiral space formed between the two ball screw grooves. The ball circulation device is for circulating the balls in the spiral space.

  The ball screw mechanism 12a having the above-described configuration is supported on the vehicle body frame 6 by supporting the ball nut 19a in a state where the ball nut 19a can rotate relative to the vehicle body frame 6. . In this state, the screw shaft side protrusion 27 of the ball screw shaft 18a is inserted inside the third through hole 16a of the shackle 10b. In such a state, when the shackle 10b swings about the support pin 17, the swing causes the ball screw shaft 18a to move through the screw shaft side convex portion 27 and the axis of the ball screw shaft 18a. The linear motion is performed in the direction (the vertical direction in FIG. 2). Then, the ball nut 19a is driven to rotate with the linear motion.

  In the case of the present embodiment, the rotation angle of the ball nut 19a is measured by a rotation angle measuring means (not shown). Then, based on the result of the measurement, an arithmetic unit (not shown) calculates the load amount of the load loaded on the vehicle body, and notifies the driver of the calculation result. The process of calculating the loading amount from the rotation angle of the ball nut 19a can be performed, for example, using a conversion map representing the relationship between the rotation angle and the loading amount. Other structures, functions and effects are the same as those of the first example of the above-described embodiment.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIG. The leaf spring suspension device 1c of the present example has a structure in which the shackle 10a provided in the structure of the first example of the above-described embodiment is omitted. For this reason, the structure of the ball nut 19b constituting the ball screw mechanism 12b is different from that of the first example of the above-described embodiment. Hereinafter, the structure of the ball screw mechanism 12b will be described.

The ball screw mechanism 12b constituting the leaf spring suspension device 1c of the present example includes a ball screw shaft 18b, a ball nut 19b, a plurality of balls (not shown), and a ball circulation device.
The ball screw shaft 18b corresponds to the rotating member described in the claims, and has a ball screw groove formed on the outer peripheral surface.
The ball nut 19b has a ball screw groove formed on the inner peripheral surface. A semi-disc-shaped nut-side mounting portion 29 is formed on a part of the outer peripheral surface of the ball nut 19b and protrudes toward the outside in a state of being long in the axial direction. A nut-side through-hole 28 is formed at the center of the nut-side mounting portion 29 so as to penetrate the nut-side mounting portion 29 in the thickness direction (the front and back direction in FIG. 3). A swing pin 11a provided at the rear end of the leaf spring 2a is inserted into the nut side through hole 28. As a result, the ball nut 19b is externally fitted to the ball screw shaft 18 in a state where only the displacement in the axial direction (the left-right direction in FIG. 3) of the ball screw shaft 18b is possible with the rotation prevented. Have been.
Each of the balls is rotatably provided in a spiral space formed between the two ball screw grooves.
The ball circulation device is for circulating the balls in the spiral space.

  The ball screw mechanism 12b having the above-described configuration is capable of rotating both ends of the ball screw shaft 18b in the axial direction with respect to the body frame 6 by a pair of rolling bearings 21, 21 on a part of the body frame 6. It is supported in a state. In this state, the nut-side mounting portion 29 of the ball nut 19b and the rear end portion (support ring portion 4b) of the leaf spring 2a are inserted into the nut-side through hole 28 of the nut-side mounting portion 29. It is connected in a swingable state by a swing pin 11a. That is, in the case of this example, the rear end of the leaf spring 2a and the ball nut 19b are directly connected (without interposing any other member). Although not shown, between the rear end (support ring 4b) of the leaf spring 2a and the outer peripheral surface of the swing pin 11a, and the inner peripheral surface of the nut-side through hole 28, Radial bearings (radial rolling bearings, radial sliding bearings) may be provided between the swing pin 11a and the outer peripheral surface.

When the leaf spring 2a is elastically deformed in such a state, the rear end of the leaf spring 2a is displaced in the front-rear direction while swinging with respect to the nut-side mounting portion 29 of the ball nut 19b. Then, with the displacement of the rear end of the leaf spring 2a in the front-rear direction, the ball nut 19b linearly moves in the axial direction of the ball screw shaft 18b. Then, with the linear movement, the ball screw shaft 18b is driven to rotate.
In the case of this example having the above-described configuration, when the leaf spring 2a bends, the warp can be absorbed only by the displacement of the ball nut 19b in the front-rear direction. Therefore, a change in the inclination angle of the rear end of the leaf spring 2a due to the deflection of the leaf spring 2a can be suppressed to a small value. Since the rear end of the leaf spring 2a can be supported at a position close to the vehicle body frame 6, the inclination angle of the rear end of the leaf spring 2a can be easily adjusted.

When the present embodiment is carried out, as shown in FIG. 4, among the swing pins 11 a, the long holes 31 formed in the front-rear direction formed in the guide member 30 supported and fixed to the vehicle body frame 6 are provided. A structure in which a portion projecting in the width direction (the width direction of the vehicle body and the front and back directions in FIG. 4) from the nut side through hole 28 may be adopted. In addition, a configuration is adopted in which a pair of guide members 30 are provided so as to sandwich the ball nut 19b from both sides in the width direction, and both ends of the swing pin 11a are inserted into the long holes 31 of both guide members 30. You can do it.
According to such a configuration, the guide member 30 guides the displacement of the ball nut 19b in the front-rear direction while supporting the radial load applied to the ball nut 19b, thereby improving the durability of the ball screw mechanism 12b. Can be improved.
Other structures, operations and effects are the same as those in the first example of the above-described embodiment.

  In practicing the present invention, not only the rotation angle of the rotating member but also the axial displacement of the linear member may be adopted as the displacement of the member constituting the conversion mechanism, which is measured by the displacement measuring means. it can.

1, 1a, 1b, 1c Leaf spring suspension device 2, 2a Leaf spring 3, 3a Axle support 4a, 4b Support ring 5 Axle 6 Body frame 7, 7a Front spring bracket 8, 8a Swing pin 9, 9a Rear Side spring bracket 10, 10a, 10b Shackle 11, 11a Swing pin 12, 12a, 12b Ball screw mechanism 13 Motor generator 14, 14a First through hole 15, 15a Second through hole 16, 16a Third through hole 17 Support Pin 18, 18a, 18b Ball screw shaft 19, 19a, 19b Ball nut 20 Nut side protrusion 21 Rolling bearing 22 Rotary shaft 23 Road surface 24 Spring side half 25 Body side half 26 Bend 27 Screw shaft side protrusion 28 Nut Side through hole 29 Nut side mounting part 30 Guide member 31 Slot

Claims (2)

A leaf spring, an axle support, a conversion mechanism, a displacement measuring unit, and a motor generator ,
The leaf spring is formed of a leaf spring that can be flexibly deformed, and one end in the front-rear direction is supported so as to be swingable with respect to the vehicle body, and the other end in the front-rear direction is displaced in the front-rear direction with respect to the vehicle body. It is supported in a possible and swingable state,
The axle support portion is for supporting an axle, and is provided at an intermediate portion in the front-rear direction of the leaf spring,
The conversion mechanism includes a ball nut which is linearly moving member, a ball screw mechanism which have a ball screw shaft which is a rotating member, connected directly or via a shackle relative to the longitudinal direction other end portion of the leaf spring are caused by the vertical distance between the said vehicle body and said axle is changed, the linear motion of the ball nut with the longitudinal direction displacement of the longitudinal other end of the leaf spring, said ball screw shaft Which translates into rotational motion,
The displacement amount measuring means is for measuring a displacement amount of a member constituting the conversion mechanism,
Said electric generator, said being connected to the ball screw shaft, on the basis of the deflection amount of change of the leaf spring caused by the vertical movement of the vehicle body, the ball nut of the ball screw shaft due to the fact that linear movement The function as a generator for converting the rotational motion into electric power, and the ball nut is driven in rotation based on energization to linearly move the ball nut and change the amount of deflection of the leaf spring, thereby obtaining the vehicle body. Having a function as a motor for adjusting the height of the
Leaf spring suspension system. The ball screw shaft is disposed so that the central axis is oriented in the front-rear direction, and is supported so as to be rotatable only with respect to the vehicle body. The suspension device according to claim 1, wherein the suspension device is connected via a shackle and is displaceable in the front-rear direction around the ball screw shaft.

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