JPH10177917A - Proportional-solenoid type actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate the magnetic flux having the constant proportional relationhip in the range, wherein the current value is zero to maximum, when the current is supplied to an exciting coil. SOLUTION: An armature 27 is arranged at the central part 27 of a case 22. A permanent magnet 34 is arranged at an exciting coil 29 and its outside in the case 22. Even when the current is not supplied to the exciting coil 29, the magnetic flux ϕ is generated in the case 22 by a permanent magnet 34. When the current is supplied, the armature 27 can be displaced at the constant proportional retionship with respect to the current in the range from the zero current value to the maximum current value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a proportional solenoid type actuator used in a damping force adjusting type hydraulic shock absorber which is mounted on, for example, a suspension system of a vehicle or the like and adjusts a damping force according to a road surface condition during traveling.

[0002]

2. Description of the Related Art As a damping force adjusting type hydraulic shock absorber using a proportional solenoid type actuator according to the prior art,
For example, there is one disclosed in JP-A-8-184334. In this type of hydraulic shock absorber, a cylinder filled with oil, a piston rod is connected, and a piston slidably fitted in the cylinder and a two-chamber inside the cylinder defined by the piston. The passage includes a passage communicating with the passage, and a damping force generating mechanism that is provided in the middle of the passage and controls a flow of the oil liquid generated in the passage by sliding of a piston in the cylinder to generate a damping force.

Further, the damping force generating mechanism is provided with a proportional solenoid type actuator for switching a passage area of the damping force generating mechanism. The damping force adjusting type hydraulic shock absorber is capable of adjusting the damping force by switching the passage area of the damping force generating mechanism by the proportional solenoid type actuator.

Here, a proportional solenoid type actuator for adjusting the passage area of the damping force generating mechanism drives a cylindrical case made of a magnetic material and an object to be driven provided outside the case. A movable core provided displaceably in the case, and provided around the movable core, forming a magnetic flux proportional to a current between the case and the movable core during energization to form the movable core. And an exciting coil to be displaced. By connecting a valve body of a control valve to the movable iron core, the passage area is adjusted in accordance with the current supplied to the exciting coil of the proportional solenoid type actuator, and the damping force is adjusted. To adjust.

In the hydraulic shock absorber configured as described above, when the passage area of the damping force generating mechanism is widened, the resistance force when the piston slides along with the expansion and contraction of the piston rod is reduced to reduce the damping force. Set the force characteristics to soft.

On the other hand, when the passage area of the damping force generating mechanism is narrowed, the resistance force when the piston slides in accordance with the expansion and contraction of the piston rod is increased to set the damping force characteristics hard. Thus, in the damping force adjusting type hydraulic shock absorber,
The damping force characteristics can be adjusted by adjusting the passage area of the damping force generation mechanism.

[0007] By selecting the soft damping force characteristic during normal running of the vehicle, vibration due to unevenness of the road surface can be absorbed to improve ride comfort.
During turning, acceleration, braking, and high-speed running, by selecting the damping force characteristic on the hard side, it is possible to suppress a change in the posture of the vehicle body and improve steering stability.

[0008]

In the above-described proportional solenoid type actuator according to the prior art, the relationship between the magnetic flux density B of the case due to the magnetic flux generated with respect to the current I supplied to the exciting coil is shown in FIG. As indicated by a broken line, in the low range of the current I (below the current IL), there is no proportional relationship due to the magnetization characteristics of the case (depending on material). Therefore, the relationship between the current I and the thrust of the movable iron core does not have a constant proportional relationship in a low current value range. Therefore, as shown by the broken line in FIG. 4, even in the relationship between the damping force F and the current I, a constant proportional relationship is not obtained in a low current region, and the displacement of the movable iron core with respect to the current I is constant as a proportional solenoid type actuator. It can be used only in the range a between IL and Imax, which are in a proportional relationship, and has the following problems.

First, when the current is equal to or lower than IL, the movable core is unstable and moves only slightly. Therefore, when the movable core is moved in the range a, a large current equal to or higher than IL is not supplied to the exciting coil. In addition, there is a problem that the resolution of the current value becomes coarse and fine control becomes impossible.

Second, when the current is used in the range of zero to IL, as described above, the damping force with respect to the current value cannot be generated in a constant proportional relationship, and the required damping force is hardly obtained. is there.

The present invention has been made in view of the above-described problems of the prior art, and the present invention can provide a "current I-magnetic flux density B" characteristic having a constant proportional relationship even when the current is low. In addition, an object of the present invention is to provide a proportional solenoid type actuator that can adjust a damping force with respect to a current in a constant proportional relationship when used in a damping force generating mechanism of a hydraulic shock absorber.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a cylindrical case and a displaceable member inside the case for driving a driving object disposed outside the case. A proportional solenoid comprising a movable core provided and an exciting coil provided around the movable core and displacing the movable core by forming a magnetic flux proportional to a current between the case and the movable core when energized; In the mold actuator, a permanent magnet that generates a magnetic flux in advance in a direction corresponding to the direction of the magnetic flux generated by the excitation coil is provided in the case.

With this configuration, the magnetic flux generated from the permanent magnet is added to the case in advance and acts on the movable core. Therefore, when the excitation coil is energized, the magnetic flux acting on the movable core from the case is constant. It can be used within the range of a proportional relationship.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below in detail with reference to the accompanying drawings. 1 to 4 show an embodiment according to the present invention. In this embodiment, a case where a proportional solenoid type actuator is used as a semi-active suspension actuator will be described.

In FIG. 1, reference numeral 1 denotes a damping force adjusting type hydraulic shock absorber provided between a main body of an automobile and wheels (neither is shown). A tube 2 enclosed therein and having a bottom side attached to a wheel, a piston 3 slidably provided in the tube 2 and defining the inside of the tube 2 as an upper oil chamber A and a lower oil chamber B; A piston rod 4 having a side fixed to the piston 3 and an upper end attached to the vehicle body; an oil passage 5 provided so as to constantly communicate the upper oil chamber A and the lower oil chamber B; A first one-way valve 6 provided to allow the flow of the oil liquid only from the lower oil chamber B to the upper oil chamber A when the piston 3 descends;
A second fluid passage is provided on the bottom side of the tube 2 so as to communicate with the oil passage 5, and allows the flow of the oil liquid only from the upper oil chamber A to the lower oil chamber B via the oil passage 5 when the piston 3 rises. The one-way valve 7, an accumulator 9 that communicates via a branch passage 8 connected to the oil passage 5, and a damping force generating mechanism 10 described later provided in the middle of the oil passage 5. .

Here, the accumulator 9 is defined by an upper gas chamber 9A and a lower oil storage chamber 9B. When the piston rod 4 is in the contraction stroke, the accumulator 9 has a volume corresponding to the volume of the piston rod 4 that has entered the tube 2. The oil liquid flows from the upper oil chamber A to the oil passage 5,
The oil is supplied to the oil storage chamber 9B through the branch passage 8 to absorb the invading volume of the piston rod 4.

Numeral 10 denotes a damping force generating mechanism. The damping force generating mechanism 10 has a bottomed cylindrical housing 11 forming an outer shell thereof.
And a spool valve body 12 (drive target) slidably disposed in the housing 11 in the axial direction, and a spool valve body 12 which is attached to the opening side of the housing 11 and drives the spool valve body 12 in accordance with the magnitude of an energizing current. And a proportional solenoid type actuator 21. On the side wall of the housing 11, a port 13 connected to the upper oil chamber A side (upstream side) of the oil passage 5 and a side wall radially opposed to the port 13 and at a position slightly shifted in the left-right direction, Lower oil chamber B of oil passage 5
And a port 14 connected to the side (downstream side). An urging spring 15 that constantly presses the spool valve element 12 toward the proportional solenoid type actuator 21 is interposed between the bottom side of the housing 11 and the spool valve element 12.

Further, an annular passage portion 12A is formed on the outer peripheral side of the spool valve body 12 in the axial middle, and by moving the spool valve body 12 in the axial direction, the passage portion 1A is formed.
The port 13 and the port 14 are connected and disconnected via 2A. On the other hand, the spool valve element 12 is moved in the axial direction via the shaft 28 of the proportional solenoid type actuator 21 fixed to the opening of the housing 11.

Here, the damping force generating mechanism 10 moves the spool valve body 12 in the axial direction against the urging spring 15 by extending and contracting the shaft 28 of the proportional solenoid type actuator 21, and The passage area of the oil passage 5 is set by adjusting the passage area of the passage portion 12A or the passage area of the port 14 and the passage portion 12A. Thereby, the damping force is adjusted by controlling the oil liquid flowing through the oil passage 5.

At the position of the spool valve element 12 shown in FIG. 1, since the passage area of the oil passage 5 is maximized, the damping force characteristic adjusted by the damping force generating mechanism 10 is set to soft. You.

However, in the damping force adjusting type hydraulic shock absorber 1, the oil liquid in the upper oil chamber A moves to the lower oil chamber B via the oil passage 5 and the one-way valve 7 during the extension stroke of the piston rod 4. At this time, the damping force generating mechanism 10 provided in the middle of the oil passage 5
As described above, the damping force can be set by adjusting the passage area of the flowing oil liquid.

On the other hand, during the contraction stroke of the piston rod 4, the oil liquid in the lower oil chamber B moves to the upper oil chamber A via the one-way valve 6, and the oil liquid corresponding to the volume of the piston rod 4 entering the oil passage 5. , Move to the accumulator 9 through the branch passage 8.
At this time, similarly to the extension stroke, the damping force generation mechanism 10
The damping force can be set by adjusting the passage area of the flowing oil liquid.

As described above, the damping force adjustable hydraulic shock absorber 1
In any case, the oil liquid can be circulated through the oil passage 5 to the damping force generating mechanism 10 through the oil passage 5 and the damping force can be generated by the damping force generating mechanism 10 in both cases of the extension stroke and the contraction stroke of the piston rod 4.

Next, the configuration of the proportional solenoid type actuator 21 used in this embodiment will be described with reference to FIG.

In the drawing, reference numeral 21 denotes a proportional solenoid type actuator, and reference numeral 22 denotes a case forming an outer shell of the proportional solenoid type actuator 21. The case 22 includes a cylindrical body 23 and an opening on one side of the cylindrical body 23. It is composed of a disc-shaped lid 24 for covering and a disc-shaped bottom plate 25 for covering the other opening of the cylindrical body 23. The cylindrical body 23, the lid 24, and the bottom plate 25 of the case 22 are each formed of a magnetic metal material such as an iron material.

Here, the lid 24 is formed so as to protrude from the center of the disk toward the outside of the case 22, and has a cylindrical mounting portion 24A mounted on the damping force generating mechanism 10, and from the center of the disk. An opposing wall portion 24 that is formed inside the case 22 and protrudes radially inward, and opposes one side of the armature 27 described below and suctions the armature 27 according to magnetic flux.
B and a tapered tapered cylindrical portion 24C formed integrally with the opposed wall portion 24B on the inner side of the case 22 and slidably guiding one side of the armature 27. Also, the lid 24
A shaft insertion hole 24D through which a shaft 28 described later is inserted is formed in the center of the shaft insertion hole 2D.
4D has a bearing 24E for slidably guiding the shaft 28.
Is installed.

Here, the tapered tubular portion 24C receives the part of the magnetic flux of the armature 27 passing in the axial direction from the radial direction (releasing part of the magnetic flux in the radial direction), thereby forming the wall facing the armature 27. The suction force of 24B is reduced as the armature 27 moves toward one end in the axial direction, so that the thrust is kept constant regardless of the displacement position of the armature 27.

The bottom plate 25 is formed so as to protrude from the center of the disk toward the inside of the case 22, and the tapered cylindrical portion 24 is formed.
The guide cylinder 2 having an inner diameter dimension substantially equal to C and having a bearing 25C mounted thereon for slidably guiding the other side of the armature 27.
5A and a screw hole 25 formed in the center of the disk, into which an adjusting screw 32 for adjusting a set load of a spring 33 described later is screwed.
B. Then, the tapered cylindrical portion 24 of the lid 24
C and armature 2 by guide cylinder 25A of bottom plate 25.
7 is formed, and an excitation coil 29 is provided between the lid 24 and the bottom plate 25 on the outer peripheral side of the space 26.

Reference numeral 27 denotes an armature housed in a space 26. The armature 27 is formed of a magnetic metal material in a substantially columnar shape.
The other end of the long, small-diameter nonmagnetic metal material shaft 28 inserted into the shaft insertion hole 24D is fixed, and a spring support 27A for supporting one end of the spring 33 is formed on the other end surface. Here, the movable core is constituted by an armature 27 and a shaft 28, and the movable core is a bearing 24E.
And the bearing 25C are positioned in the radial direction.

Reference numeral 29 denotes an exciting coil, and the exciting coil 2
9 is located in a space formed by the lid 24, the cylindrical body 23 and the bottom plate 25, and is provided around the coil bobbin 30. By supplying a current to the exciting coil 29, the magnetic flux Φ generated from the exciting coil 29 acts on the armature 27 via the bottom plate 25 of the case 22, the cylinder 23 and the lid 24. Reference numeral 31 denotes a non-magnetic pipe for positioning the tapered tube portion 24C and the guide tube portion 25A in the radial direction.

An adjusting screw 32 is screwed into a screw hole 25B of the bottom plate 25, and has a spring 3
3 is formed with a spring receiver 32A for supporting the other end, and a negative flat head 32B is formed on the other side surface.

Reference numeral 33 denotes a spring which applies a biasing force so as to constantly bias the armature 27 toward one end. The spring 33 is disposed between the spring bearing 27A of the armature 27 and the spring bearing 32A of the adjusting screw 32. ing. Then, by adjusting the screwing amount of the adjusting screw 32 into the screw hole 25B,
The resistance of the spring 33 between the adjusting screw 32 and the armature 27 is adjusted by changing the set load of the spring 33, so that the armature 27 with respect to the magnetic flux Φ generated by the exciting coil 29 and the magnetic flux Φ generated by the permanent magnet 34 described later. ,
As a result, the amount of movement of the shaft 28 is finely adjusted.

Reference numeral 34 denotes a cylindrical permanent magnet provided in the case 22 according to the present embodiment. The permanent magnet 34 is disposed between the outer peripheral side of the exciting coil 29 and the cylindrical body 23, and A magnetic flux φ is generated from the magnet 34, and the magnetic flux φ always acts on the case 22 even when the excitation coil 29 is not energized.

The direction of the magnetic flux φ generated by the permanent magnet 34 is opposite to the direction of the magnetic flux φ generated when the exciting coil 29 is energized (arrow in FIG. 2). Armature 27 as well as Φ
Acts on the opposed wall portion 24B. here,
When the exciting coil 29 is in a non-energized state, the magnetic flux φ generated by the permanent magnet 34 indicates the difference between the current I and the magnetic flux density B in the “current I−magnetic flux density B” characteristic shown by the broken line in FIG. The magnetic flux density BL is set at the minimum current IL at which the range a where the relationship becomes a constant proportional relationship starts.

However, in the proportional solenoid type actuator 21 according to the present embodiment, before the current I is supplied to the exciting coil 29, the magnetic flux φ whose magnetic flux density becomes BL acts on the case 22 from the permanent magnet 34. Therefore, the characteristic of the magnetic flux density B with respect to the current I is as shown by the solid line in FIG. That is, by applying the magnetic flux φ to the case 22 in advance, the relationship between the current I and the magnetic flux density B can be changed.
The current flowing through the exciting coil 29 can be in a proportional range from zero to Imax (entire range) without passing through the range of the magnetization characteristics of No. 2 (a range that does not have a proportional relationship (see a broken line in FIG. 3)).

Thus, when the proportional solenoid type actuator 21 according to the present embodiment is used for the damping force generating mechanism 10, the displacement of the armature 27 is driven in a constant proportional relation to the current I to the exciting coil 29. Therefore, the length of the shaft 28 protruding from the case 22 can be adjusted in a constant proportional relationship by the current I supplied to the proportional solenoid type actuator 21. As a result, the damping force generated by the damping force generating mechanism 10 is reduced to the current I in the entire range from zero to Imax as shown by the characteristic of the damping force F with respect to the current I shown by the solid line in FIG.
Can be controlled so as to have a constant proportional relationship with respect to.

Accordingly, the proportional solenoid type actuator 21 changes the current I supplied to the exciting coil 29 from zero to Ima.
Since the damping force F can have a constant proportional relationship with respect to a wide current range of x, the current control resolution can be increased and the average power consumption can be reduced. The damping force adjusting hydraulic shock absorber 1 can be configured as a semi-active suspension in which the damping force can be finely adjusted by the proportional solenoid type actuator 21, and the riding comfort of the vehicle can be improved.

In the above-described embodiment, the permanent magnet 34 is shown as a cylindrical one, but the present invention is not limited to this.
Any shape may be used as long as it generates a magnetic flux that passes from 2 to the armature 27 in advance.

[0039]

As described above in detail, according to the present invention, the case of the proportional solenoid type actuator is arranged on the movable iron core from the case and generates a magnetic flux in advance in a direction corresponding to the magnetic flux generated from the exciting coil. Since the permanent magnet is provided, the magnetic flux generated from the permanent magnet is added to the magnetic flux generated from the exciting coil in advance, and when the exciting coil is energized, the current and the magnetic flux can be used in a range where a constant proportional relationship exists. The current and the displacement of the movable core can be used in a fixed proportional relationship. For example, when a proportional solenoid type actuator is used for the damping force generating mechanism of the hydraulic shock absorber, it becomes possible to adjust the damping force with respect to the current in a fixed proportional relationship, thereby improving the resolution of the current value and reducing the damping force. Adjustment is possible to improve ride comfort.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an overall configuration of a damping force adjusting type hydraulic shock absorber using a proportional solenoid type actuator according to the present embodiment.

FIG. 2 is a longitudinal sectional view showing a proportional solenoid type actuator according to the embodiment.

FIG. 3 is a characteristic diagram showing a comparison between a current supplied to an excitation coil and a magnetic flux density of the proportional solenoid type actuator of the present embodiment and a conventional art.

FIG. 4 is a characteristic diagram comparing the relationship between the current supplied to the excitation coil of the proportional solenoid type actuator of the present embodiment and the conventional art and the damping force of the hydraulic shock absorber;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 12 Spool valve body (object to be driven) 21 Proportional solenoid type actuator 22 Case 23 Cylindrical body 24 Lid 25 Bottom plate 27 Armature (movable iron core) 28 Shaft (movable iron core) 29 Exciting coil 33 Spring 34 Permanent magnet

Claims (1)

[Claims] 1. A cylindrical case, a movable core displaceably provided in the case for driving a driving object disposed outside the case, and a movable core provided around the movable iron core, A proportional solenoid type actuator comprising an excitation coil for displacing the movable core by forming a magnetic flux proportional to a current between the case and the movable core when energized, wherein the excitation coil is generated in the case. A proportional solenoid type actuator comprising a permanent magnet which generates a magnetic flux in a direction corresponding to a direction of a magnetic flux in advance.