CN215410014U - Suspension device - Google Patents

Abstract

The suspension device of the present invention suppresses the generation of jamming and absorbs the load of displacement in both directions. The suspension device of the present invention comprises: a ball screw mechanism (30) having a ball screw shaft (32) and a ball screw nut (34) disposed on the outer peripheral surface of the ball screw shaft (32), the ball screw mechanism being capable of mechanically converting the rotational motion of the ball screw shaft (32) and the linear motion of the ball screw nut (34); and a motor (14) that imparts rotational drive force to the ball screw shaft (32), and that is provided with a first elastic body (48) and a second elastic body (50) that are located on the outer periphery of the ball screw shaft (32) and that extend in the axial direction, respectively, on both axial end sides of the ball screw nut (34).

Description

Suspension device

Technical Field

The present invention relates to a levitation (levitation) device that generates a damping force by using a rotational driving force of a motor.

Background

For example, patent document 1 discloses a suspension device that generates a damping force by displacing a damper (damper).

In the levitation device disclosed in patent document 1, the rotational driving force of the motor is transmitted to the ball screw mechanism via a belt (belt) and a motor-side pulley and a screw-shaft-side pulley from which the belt is suspended. In the ball screw mechanism, a rotational driving force transmitted from a motor is converted into a linear motion, and a ball screw nut is reciprocated linearly.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent No. 6199821 publication

SUMMERY OF THE UTILITY MODEL

[ problem to be solved by the utility model ]

Further, in the suspension device disclosed in patent document 1, the ball screw nut supporting the ball screw shaft is inclined with respect to the axis of the ball screw shaft and is engaged therewith, and thus there is a possibility that friction (friction) increases and smoothness deteriorates, or there is a possibility that durability of the ball screw mechanism decreases.

Further, in the damper, since the ball screw nut is displaced in both the expansion side and the contraction side, it is necessary to absorb the load against the displacement in both directions.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a suspension device which has strength and toughness against an impact load at the start of a stroke or at the return in the stroke direction, and which is excellent in smoothness, while suppressing an increase in friction due to the ball screw nut coming into contact with the axis of the ball screw shaft, and a decrease in durability of the ball screw mechanism.

[ means for solving problems ]

To achieve the object, the present invention includes: a feed screw mechanism having a feed screw shaft and a feed nut disposed on an outer peripheral surface of the feed screw shaft, the feed screw mechanism being capable of mechanically converting a rotational motion of the feed screw shaft and a linear motion of the feed nut; and a motor that applies a rotational driving force to the feed screw shaft, and elastic bodies that are located on the outer periphery of the feed screw shaft and extend in the axial direction are provided on both axial end sides of the feed nut.

[ effects of the utility model ]

In the present invention, the following suspension device is available: the increase of friction and the deterioration of smoothness and the reduction of durability caused by the engagement of the feed nut with respect to the axis of the feed screw shaft can be prevented, and the impact load generated at the start of the stroke or at the return in the stroke direction can be absorbed.

Drawings

Fig. 1 is a sectional configuration view of a suspension device according to an embodiment of the present invention, taken along an axial direction.

Fig. 2 is a partially enlarged sectional structural view of fig. 1.

Fig. 3 is a perspective view of the ball screw nut.

Fig. 4 is an exploded perspective view of the ball screw nut.

Fig. 5 is a perspective view of the first elastic body (second elastic body).

Fig. 6 is an exploded perspective view of the torus taken out of the first elastic body (second elastic body).

[ description of reference numerals ]

10: suspension device

14: motor (electric machine)

30: ball screw mechanism (feed screw mechanism)

32: ball screw shaft (feed screw shaft)

34: ball screw nut (feed screw nut)

42: first nut (ball screw nut)

44: second nut (first joint)

46: third nut (second joint)

48: first elastomer (elastomer)

50: second elastomer (elastomer)

60: claw part

63: ring body

64: convex part

74: torus (component having higher strength than each elastic body)

Detailed Description

Next, embodiments of the present invention will be described in detail with reference to the drawings.

Fig. 1 is a sectional configuration view of a suspension device according to an embodiment of the present invention along an axial direction, and fig. 2 is a partially enlarged sectional configuration view of fig. 1. In each drawing, "up and down" indicates a vehicle up and down direction (vertical up and down direction).

As shown in fig. 1, a suspension device 10 according to an embodiment of the present invention is disposed between a vehicle body and wheels, and includes: a substantially cylindrical housing 12 which is vertically stretchable; and a motor housing 16 coupled to a lower end portion of the housing 12 and having motors (electric motors) 14 arranged in parallel along an axial direction of the housing 12. A communication passage 18 is provided between the lower end of the housing 12 and the lower end of the motor housing 16 to communicate the chamber of the lower end of the housing 12 with the chamber of the motor housing 16.

The upper end portion of the housing 12 is attached to a vehicle body side (for example, a damper base (not shown)). The lower end of the casing 12 is attached to, for example, a trailing arm (trailing arm) or a lower swing arm (lower arm).

As shown in fig. 1, the housing 12 includes an inner cylinder 20 attached to the vehicle body side, and an outer cylinder 22 slidably accommodating the inner cylinder 20.

A ball screw mechanism (feed screw mechanism) 30 is disposed in the housing 12. The ball screw mechanism 30 includes a ball screw shaft (feed screw shaft) 32, a ball screw nut (feed screw nut) 34, a plurality of balls 36, and a support portion 38. In the present embodiment, the ball screw mechanism 30 including the plurality of balls 36 is used, but a feed screw mechanism not shown in the drawings which does not include the plurality of balls 36 may be used.

The ball screw shaft 32 extends in the axial direction within the housing 12. The ball screw nut 34 is disposed on the outer periphery of the ball screw shaft 32, and is provided so as to be displaceable along the axial direction of the ball screw shaft 32 by transmission of a rotational driving force from the ball screw shaft 32. The balls 36 are provided so as to roll and circulate along a track formed between the screw groove of the ball screw shaft 32 and the groove portion of the ball screw nut 34. The support portion 38 rotatably supports the lower end portion of the ball screw shaft 32 via a bearing 40.

A ball screw nut structure including a ball screw nut 34 is attached to the lower end portion of the inner tube 20, and is provided so as to be displaced integrally with the inner tube 20. The ball screw nut 34 includes a structure in which a plurality of components are integrally assembled, and is configured by a member through which an elastic body is interposed, as will be described later.

Fig. 3 is a perspective view of the ball screw nut, and fig. 4 is an exploded perspective view of the ball screw nut.

Specifically, as shown in fig. 3 and 4, the ball screw nut includes a first nut (ball screw nut) 42, a second nut (first joint) 44, a third nut (second joint) 46, a first elastic body (elastic body) 48, a second elastic body (elastic body) 50, and a pair of annular bodies 74 (see fig. 4 to 6). In the present embodiment, both ends of the ball screw nut 42 in the axial direction are joint structures, and the same structure is adopted at both ends, but the present invention is not limited to this. For example, one side of the ball screw nut 42 does not necessarily need to be a joint, and an elastic body having elasticity (spring) elements in the up and down direction, not shown, without a joint may be used.

The first nut 42 is disposed at the center of the ball screw nut 34 in the axial direction, and is longer than the second nut 44 and the third nut 46. The second nut (first joint) 44 and the third nut (second joint) 46 are disposed at both ends of the first nut 42 in the axial direction, respectively, and are integrally joined by a joint structure described later.

The first nut 42 has: a cylindrical portion 54 having a constant outer diameter in the axial direction; and a plurality of coupling claws 56 that protrude from the upper end portion and the lower end portion of the cylindrical portion 54 toward the second nut 44 and the third nut 46, respectively, in the axial direction. The plurality of coupling claws 56 are constituted by six claws that are separated at equal angles in the circumferential direction at the end of the cylindrical portion 54.

The second nut (first joint) 44 and the third nut (second joint) 46 each have substantially the same configuration, and have a substantially disk-shaped nut body 58 and claw portions 60 projecting from the bottom surface of the nut body 58 toward the first nut 42 in the axial direction. The claw portion 60 is constituted by a plurality of (six in the present embodiment) locking claws 62 that are equally spaced apart from the bottom surface of the nut body 58 in the circumferential direction. The coupling claws 56 of the first nut 42 and the claw parts 60 of the second nut 44 and the third nut 46 are configured to have the same projection amount (projection dimension).

On both axial end sides of the ball screw nut 34, a first elastic body 48 and a second elastic body 50 are provided, which are located on the outer periphery of the ball screw shaft 32 and extend in the axial direction. The first elastic body 48 is interposed between the first nut 42 and the second nut 44 via joint structures. The second elastic body 50 is interposed between the first nut 42 and the third nut 46 via joint structures.

Fig. 5 is a perspective view of the first elastic body (second elastic body), and fig. 6 is an exploded perspective view of the torus taken out of the first elastic body (second elastic body).

The first elastic body 48 and the second elastic body 50 have the same structure and are made of an elastic material such as rubber. As shown in fig. 3 and 4, the first elastic body 48 and the second elastic body 50 have: an annular body 63 surrounding the outer peripheral surface of the ball screw shaft 32; and a protrusion 64 provided on the outer peripheral surface of the annular body 63 and having a shape in which rectangular pulses (pulse signals) are continuous in the circumferential direction.

As shown in fig. 2, the cross section of the annular body 63 extends along the axial direction of the claw portions 60 of the second nut 44 and the third nut 46. The cross section of the projection 64 rises from the outer peripheral surface of the annular body 63, and extends radially outward of the claw portions 60 of the second nut 44 and the third nut 46.

In one pulse of the convex portion 64, a plurality of (twelve in the present embodiment) engagement grooves extending in the axial direction and separated at equal angles in the circumferential direction are arranged.

As shown in fig. 5, the plurality of engagement grooves include a first engagement groove 66 and a second engagement groove 68, which are opposite to each other in the locking directions (restricting direction, abutting direction) of the coupling claw 56 and the claw portion 60, between adjacent engagement grooves. The first engaging groove 66 has a first engaging portion 70 that restricts the end in the insertion direction, and the second engaging groove 68 has a second engaging portion 72 that is located in the opposite direction to the first engaging portion 70 and restricts the end in the insertion direction.

That is, the first elastic body 48 has the first engaging groove 66, and the first engaging groove 66 allows the coupling claw 56 on the upper end side of the first nut 42 to pass through the first nut 42 side and abut against the first locking portion 70 provided on the second nut 44 side, thereby locking (restricting) the tip of the coupling claw 56. The first elastic body 48 has a second engaging groove 68, the second engaging groove 68 is adjacent to the first engaging groove 66, and the claw portion 60 of the second nut 44 is inserted from the second nut 44 side and abuts against a second locking portion 72 provided on the first nut 42 side, thereby locking (restricting) the tip of the claw portion 60. The first engaging grooves 66 and the second engaging grooves 68 are alternately and continuously arranged along the circumferential direction of the first elastic body 48.

The second elastic body 50 has a first engaging groove 66, and the first engaging groove 66 allows the coupling claw 56 on the lower end portion side of the first nut 42 to pass through the first nut 42 side and to abut against a first locking portion 70 provided on the third nut 46 side, thereby locking (restricting) the tip end of the coupling claw 56. The second elastic body 50 has a second engaging groove 68, the second engaging groove 68 is adjacent to the first engaging groove 66, and the claw portion 60 of the third nut 46 is inserted from the third nut 46 side and abuts against a second locking portion 72 provided on the first nut 42 side, thereby locking (restricting) the tip of the claw portion 60. The first engaging grooves 66 and the second engaging grooves 68 are alternately and continuously arranged along the circumferential direction of the second elastic body 50. When the first elastic body 48 and the second elastic body 50 are viewed from the outside in the radial direction, the first engagement groove 66 and the second engagement groove 68 are substantially rectangular.

In the present embodiment, the spring constant of the first elastic body 48 is the same as the spring constant of the second elastic body 50. However, as will be described later, the spring constant of the first elastic body 48 may be different from the spring constant of the second elastic body 50.

As shown in fig. 6, a ring 74 is embedded in each of the first elastic body 48 and the second elastic body 50 on the inner diameter side (inside). The annular body 74 includes, for example, a steel pipe made of metal or an annular body made of resin, and is formed of a member having a higher strength than the first elastic body 48 and the second elastic body 50.

Returning to fig. 1, a rotational driving force transmission mechanism 76 that transmits the rotational motion of the motor 14 to the ball screw shaft 32 is disposed between the motor shaft 14a of the motor 14 and the ball screw shaft 32. This rotational drive force transmission mechanism 76 includes: a motor-side pulley 78 coupled to the motor shaft 14 a; a screw shaft-side pulley 80 connected to the ball screw shaft 32 side; and a belt 82 suspended from the motor-side pulley 78 and the screw-shaft-side pulley 80, respectively, and transmitting the rotational driving force of the motor 14 to the ball screw shaft 32 by rotating the screw-shaft-side pulley 80 integrally with the ball screw shaft 32.

The motor-side pulley 78 is rotatably supported via a bearing 84 disposed in the motor case 16. The screw shaft-side pulley 80 is rotatably supported via a bearing 86 disposed in a chamber at the lower end portion of the housing 12.

The bearing 86 includes, for example, a double row angular contact ball bearing, and includes an outer ring in which a pair of divided annular bodies are integrally connected, an inner ring in which a pair of divided annular bodies are integrally connected, and a plurality of balls arranged to be rollable between the outer ring and the inner ring.

The suspension device 10 of the present embodiment is basically configured as described above, and the operation and operational effects thereof will be described below.

The suspension device 10 of the present embodiment generates a damping force electromagnetically by the motor 14, not by a conventional device using a hydraulic or incompressible fluid. Specifically, when an external force is input to the suspension device 10, the ball screw nut 34 linearly moves along the axial direction of the ball screw shaft 32 integrally with the inner tube 20. The ball screw shaft 32 rotates by converting the linear motion of the ball screw nut 34 into a rotational motion. The rotation of the ball screw shaft 32 is transmitted to the motor 14 via the screw shaft-side pulley 80, the belt 82, and the motor-side pulley 78, and induced electromotive force is generated in the motor 14.

Therefore, a control unit, not shown, that controls the motor 14 generates a rotational driving force for rotating the motor 14 in the opposite direction based on the induced electromotive force generated by the motor 14. The ball screw shaft 32 receives the rotational driving force from the motor 14, thereby attenuating the linear motion of the ball screw nut 34. As a result, the suspension device 10 can alleviate vibration and the like input by external force.

In the present embodiment, the ball screw nut 34 is provided with a first elastic body 48 and a second elastic body 50, which are located on the outer periphery of the ball screw shaft 32 and extend in the axial direction, on both axial end sides thereof. Thus, in the present embodiment, the load applied to the ball screw nut 34 when the inner cylinder 20 and the outer cylinder 22 expand and contract relative to each other can be appropriately absorbed by the first elastic body 48 and the second elastic body 50.

In the present embodiment, the first elastic body 48 and the second elastic body 50 are disposed on the outer periphery of the ball screw shaft 32, and thus, for example, the first elastic body 48 and/or the second elastic body 50 can absorb the engagement of the ball screw shaft 32 with respect to the ball screw nut 34 due to the inclination. Thus, in the present embodiment, it is possible to suppress an increase in friction due to the ball screw nut 34 coming into abutment against the ball screw shaft 32, which leads to deterioration in smoothness, and a reduction in durability of the ball screw mechanism 30. In the present embodiment, the first elastic body 48 and the second elastic body 50 are disposed on the outer periphery of the ball screw shaft 32, so that high-frequency vibration transmitted from the road surface can be blocked to improve the smoothness, and vibration generated inside the suspension device 10 can be attenuated to reduce the operating sound of the suspension device 10.

Further, in the present embodiment, the ball screw nut 34 is constituted by three members including the first nut 42, the second nut 44, and the third nut 46 with the first elastic body 48 and the second elastic body 50 interposed therebetween. In the present embodiment, the first elastic body 48 and the second elastic body 50 are respectively interposed between the first nut 42 and the second nut 44, and between the first nut 42 and the third nut 46, whereby the first elastic body 48 and the second elastic body 50 can be prevented from being displaced.

In the present embodiment, the cross section of the annular body 63 constituting the first elastic body 48 and the second elastic body 50 extends along the axial direction of the claw portions 60 of the second nut 44 and the third nut 46 (see fig. 2). Accordingly, when the inner tube 20 and the outer tube 22 expand and contract relative to each other, the claw portions 60 of the second nut 44 and the third nut 46 and the coupling claws 56 of the first nut 42 are prevented from coming into contact with each other to generate collision noise, and the inclination of the ball screw shaft 32 is prevented.

In the present embodiment, the cross section of the convex portion 64 constituting the first elastic body 48 and the second elastic body 50 rises from the outer peripheral surface of the annular body 63 and extends radially outward of the claw portion 60 of the second nut 44 and the third nut 46 (see fig. 2). Accordingly, the convex portions 64 of the first elastic body 48 and the second elastic body 50 are sandwiched between the distal ends of the claw portions 60 of the second nut 44 and the third nut 46 and the distal end of the coupling claw 56 of the first nut 42, respectively, and the first elastic body 48 and the second elastic body 50 can be prevented from being involved in the ball screw shaft 32.

In the present embodiment, the spring constant of the first elastic body 48 is the same as the spring constant of the second elastic body 50. This can suppress the occurrence of the engagement between the ball screw shaft 32 and the ball screw nut 34 with good balance.

On the other hand, when the spring constant of the first elastic body 48 is different from the spring constant of the second elastic body 50, there is an advantage that the thrust responsiveness can be further changed in the thrust direction of the ball screw shaft 32.

In the present embodiment, a torus 74 having a higher strength than the first elastic body 48 and the second elastic body 50 is disposed inside the first elastic body 48 and the second elastic body 50 (see fig. 6). This prevents the first elastic body 48 and the second elastic body 50 from being deteriorated and biting into the ball screw shaft 32.

Claims (7)

1. A suspension arrangement, comprising:

a feed screw mechanism having a feed screw shaft and a feed nut disposed on an outer peripheral surface of the feed screw shaft, the feed screw mechanism being capable of mechanically converting a rotational motion of the feed screw shaft and a linear motion of the feed nut; and

a motor for applying a rotational driving force to the feed screw shaft,

elastic bodies which are located on the outer periphery of the feed screw shaft and extend in the axial direction are respectively arranged on the two axial end sides of the feed nut.

2. Suspension device according to claim 1,

the feed nut includes a member interposing the elastic body.

3. Suspension device according to claim 2,

the member interposed by the elastic body includes a first nut positioned in the middle of the feed nut, and a second nut and a third nut positioned at both ends of the middle of the first nut,

the second nut and the third nut have claw portions projecting in the axial direction of the first nut,

the elastic body has an annular body surrounding an outer peripheral surface of the feed screw shaft,

the cross section of the annular body extends along the axial direction of the claw part.

4. Suspension device according to claim 2,

the member interposed by the elastic body includes a first nut positioned in the middle of the feed nut, and a second nut and a third nut positioned at both ends of the middle of the first nut,

the second nut and the third nut have claw portions projecting in the axial direction of the first nut,

the elastic body has an annular body surrounding an outer peripheral surface of the feed screw shaft, and a protruding portion protruding from an outer peripheral surface of the annular body,

the cross section of the convex portion extends in the radial direction of the claw portion.

5. Suspension device according to claim 1,

the spring constants of the elastic bodies are respectively the same.

6. Suspension device according to claim 1,

the spring constants of the elastic bodies are different from each other.

7. Suspension device according to claim 1,

a member having a higher strength than the elastic bodies is disposed inside the elastic bodies.

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