JP2627621B2 - Rotary Actuator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary actuator suitably used for, for example, a damping force-adjustable hydraulic shock absorber or the like, and more particularly to a rotary actuator generated during operation between a fixed shaft and a sleeve. The present invention relates to a rotary actuator capable of reliably reducing abnormal noise such as interference noise.

(Prior art)

Generally, in a damping force adjusting type hydraulic shock absorber, a rotary actuator is attached to a protruding end of a piston rod, and the rotary actuator rotates a valve mechanism in a cylinder through an adjusting rod to reduce a damping force generated in the cylinder. For example, adjustment is appropriately made in two stages of hardware and software.

Therefore, FIGS. 5 and 6 show a conventional rotary actuator.

In the drawings, reference numeral 1 denotes a covered casing, and the casing 1 is composed of a covered cylindrical case 2 and a bottom plate 3 covering the bottom side of the case 2. A small-diameter cylindrical portion 3A for projecting an output shaft 21 described later
Is protruding. Reference numeral 4 denotes a fixed shaft fixed to the canopy portion 2A of the case 2 by cantilevering or the like using means such as caulking. The fixed shaft 4 is disposed coaxially with the cylindrical portion 3A of the bottom plate 3, and the casing 1 It extends downward in the axial direction, and its lower end is a free end.

Reference numeral 5 denotes a cylindrical sleeve rotatably fitted on the outer periphery of the fixed shaft 4, and the lower end of the sleeve 5 extends downward to a position beyond the free end of the fixed shaft 4, and has a lower end. A pair of diametrically opposed notches 5A, 5A
Are formed in a substantially U shape upward from the lower surface side. The sleeve 5 is connected to an output shaft 21 to be described later via each notch 5A, and rotates integrally with the output shaft 21.

Reference numeral 6 denotes a rotor provided so as to be integrally rotatable with the sleeve 5. The rotor 6 is formed in a thick plate shape by, for example, a laminated iron core, and a core 7 having a central portion fixed to the outer periphery of the sleeve 5. A resin molded portion 8 which covers the upper and lower surfaces of the core 7 and has cylindrical boss portions 8A and 8B provided on the upper and lower sides of the central portion to cover the outer periphery of the sleeve 5 in the axial direction; 8
And a coil 9 which forms a magnetic field in the core 7. The core 7 and the radially outer portion of the mold portion 8 have a pair of arc-shaped portions 7A, 7A, 8C as shown in FIG. , 8
C. The rotor 6 is used for each brush 1 to be described later.
When power is supplied to the coil 9 via 1, the coil 9 rotates integrally with the sleeve 5 about the fixed shaft 4.

Reference numerals 10 and 10 denote a pair of brush holders integrally formed with the mold portion 8 of the rotor 6, and each of the holders 10
And projecting radially outward from a central portion of the mold portion 8A so as to be orthogonal to. Reference numerals 11 and 11 denote a pair of brushes slidably held at the tip end of each holder 10, and each brush 11 is connected to both ends of the coil 9 of the rotor 6, respectively.
The front end surface is in sliding contact with arc-shaped conductive plates 13 and 14 disposed on the back surface of the canopy portion 2A of the case 2 via an insulating member 12. The insulating member 12 is provided with lead plates 15 and 16 which are located between the conductive plates 13 and 14 and are connected to a changeover switch (not shown) for changing the rotation direction of the rotor 6. Plates 13, 14, 15, 16 are harness 17
Through an external power supply circuit (not shown).

Numerals 18 and 18 denote stators located radially outward of the rotor 6 and fixed to the inner peripheral surface of the case 2, and each of the stators 6 is formed in an arc shape by a permanent magnet.

Reference numeral 19 denotes a movable stopper integrally provided on one of the arc-shaped portions 8C of the rotor 6, and reference numerals 20 and 20 denote fixed-side stoppers fixed to the back surface of the canopy portion 2A of the case 2.
Are formed of a cushioning material such as rubber, and are disposed at predetermined angular intervals in the circumferential direction of the case 2. Each of the stoppers 20 abuts on the movable-side stopper 19 to regulate the clockwise or counterclockwise rotation position of the rotor 6. 21 is the sleeve 5
A small diameter pin 22 is fixed to the upper end of the output shaft 21, and both ends of the pin 22 are engaged with the respective notches 5 A of the sleeve 5. And the output shaft 22
Of the bottom plate 3 protrudes out of the casing 1 via the cylindrical portion 3A of the bottom plate 3, and has a slot 21A formed at the lower end thereof for engaging with an adjusting rod (both not shown) of the hydraulic shock absorber. . In FIG. 6, the output shaft 21 and the like are removed.

The rotary actuator according to the prior art has the above-described configuration. The casing 1 is fixed to the piston rod protruding end of the hydraulic shock absorber via the bottom plate 3 and the like, and the output shaft
21 is integrally rotatably connected to the adjustment rod via a slot 21A. When power is supplied from an external power supply to the coil 9 of the rotor 6 via the harnel 17, the plates 13, 14 and the brushes 11, the rotor 6 rotates clockwise or counterclockwise, and is movable. At the position where the stopper 19 on the side contacts (collides) with each stopper 20 on the fixed side, the rotational position is regulated and stops at that position until the next power supply.

At this time, since the sleeve 5 rotates around the fixed shaft 4 together with the rotor 6, the adjustment rod connected to the output shaft 21 also rotates integrally, and the damping force adjustment provided in the cylinder of the hydraulic shock absorber is performed. The valve mechanism (not shown) is rotated through an adjustment rod to a position where the rotor 6 stops, and adjusts the generated damping force in two stages, for example, hardware and software.

[Problems to be solved by the invention]

However, in the above-described related art, since the sleeve 5 is rotatably fitted to the outer periphery of the fixed shaft 4 fixed to the case 2, a clearance is provided between the sleeve 5 and the fixed shaft 4. become. Therefore, when the rotor 6 is rotated and the movable-side stopper 19 collides with each of the fixed-side stoppers 20, each stopper 20 made of a buffer material such as rubber can reduce the collision sound. Since the sleeve 5 that rotates together with the fixed shaft 4 is rattled by the clearance, the sleeve 5 interferes with the outer periphery of the fixed shaft 4 and has a disadvantage that abnormal noise such as interference noise is generated.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and the present invention provides a buffering action such as an oil damper between the fixed shaft and the sleeve by filling the grease between the fixed shaft and the sleeve. It is an object of the present invention to provide a rotary actuator capable of reliably reducing abnormal noise.

[Means for solving the problem]

In order to solve the above-described problems, the present invention provides a covered casing, a fixed shaft fixed to the casing by cantilever support, and extending in the casing in an axial direction, and rotatable around an outer periphery of the fixed shaft. And a rotor provided integrally rotatable with the sleeve, a stator provided on the casing at a position radially outward of the rotor, and the rotor and the casing. In a rotary actuator comprising a stopper provided to regulate the rotational position of the rotor, an annular grease reservoir filled with grease is formed between the fixed shaft and the sleeve. The configuration is adopted.

[Action]

According to the above configuration, in a state where the sleeve is rotating together with the rotor around the fixed shaft on the casing side,
When the rotation of the rotor is stopped by the stopper, the remaining rotational force (inertial force) of the rotor acts on the sleeve, so that the sleeve is eccentric with respect to the fixed shaft. The clearance is partially reduced so that the clearance tends to collide with the outer peripheral portion of the fixed shaft. However, the grease in the annular grease reservoir formed between the fixed shaft and the sleeve exerts the same buffering action as the oil damper between the fixed shaft and the sleeve. Can be suppressed, and the space between the fixed shaft and the sleeve can be maintained in a lubricated state.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. In the embodiment, the same components as those in the prior art shown in FIGS.
The description is omitted.

FIGS. 1 and 2 show a first embodiment of the present invention.

In the drawing, reference numeral 31 denotes a fixed shaft fixed to the canopy portion 2A of the case 2 by cantilever support. The fixed shaft 31 is formed substantially in the same manner as the fixed shaft 4 described in the related art. The sleeve 5 is rotatably fitted in the. However, a peripheral groove 31A as an annular grease reservoir for filling grease G is formed between the outer peripheral surface of the fixed shaft 31 and the inner peripheral surface of the sleeve 5 in the axial direction.
1A extends in the axial direction of the fixed shaft 31 with a predetermined length. The grease G filled in the circumferential groove 31A
Forms an oil film between the fixed shaft 31 and the sleeve 5,
In addition to providing a lubricating action to both, a buffering action described later is caused.

The rotary actuator according to the present embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, a circumferential groove 31A as a grease reservoir is formed on the outer periphery of the axially intermediate portion of the fixed shaft 31, and the grease G is provided between the circumferential groove 31A of the fixed shaft 31 and the sleeve 5.
Is filled, the oil film can be formed between the fixed shaft 31 and the sleeve 5 by the grease G, and a lubricating action is given to both, so that the sleeve 5 can be smoothly rotated with respect to the fixed shaft 31. it can.

Further, the grease G filled between the circumferential groove 31A and the sleeve 5 causes the movable-side stopper 19 to collide with the fixed-side stopper 20 due to the rotation of the rotor 6, and the sleeve 5 moves between the fixed shaft 31 and the fixed shaft 31. When there is a play in the direction of arrow A in FIG. 2 with respect to the fixed shaft 31 due to the clearance, and the eccentricity is to be shifted from the position indicated by the two-dot chain line to the solid line position, the viscous resistance of the grease G is opposed to this. A buffering force in the direction of arrow B can be generated, and the same buffering effect as an oil damper or the like can be exerted.

That is, when the movable-side stopper 19 collides with the fixed-side stopper 20, the sleeve 5 moves from the position indicated by the two-dot chain line to the position indicated by the solid line in FIG. Circumferential groove that becomes grease reservoir when eccentric to
The grease G in 31A is formed by reducing the grease reservoir portion on the upper left side of the center line shown in FIG. The fluid flows to the lower right side, and a buffering action can be exerted by the flow resistance (viscous resistance) at this time, and a buffering force in the direction of arrow B can be generated against the external force in the direction of arrow A.

As a result, the collision of the sleeve 5 with the fixed shaft 31 can be reliably mitigated by the buffering force, and the generation of abnormal noise such as interference noise between the sleeve 5 and the fixed shaft 31 can be effectively suppressed. Sound generation can be reduced. Although FIG. 2 shows an example in which the sleeve 5 is eccentric with respect to the fixed shaft 31 in the direction of arrow A, an annular grease reservoir is formed between the sleeve 5 and the fixed shaft 31 by the circumferential groove 31A. Accordingly, the buffering action of the grease as described above can be reliably exerted regardless of the eccentric direction of the sleeve 5 with respect to the fixed shaft 31 in any direction of 360 °.

Therefore, according to the present embodiment, abnormal noise generated when the movable-side stopper 19 collides with the fixed-side stopper 20 and the rotor 6 is stopped is greatly reduced as compared with the conventional art. Various effects can be obtained, such as reduction in the number of the output shafts 21 and the smooth stop of the output shaft 21 at a predetermined position.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that two circumferential grooves 41A, 41A serving as grease reservoirs are axially separated on the outer periphery of an intermediate portion of the fixed shaft 41. It has been provided.

Thus, also in the present embodiment having the above-described configuration, it is possible to obtain substantially the same operation and effect as in the first embodiment.

Next, FIG. 4 shows a third embodiment of the present invention. The feature of this embodiment is that a circumferential groove 51A as a grease reservoir is provided on the outer periphery of the axially intermediate portion of the fixed shaft 51, and the inside of the circumferential groove 54A is formed. O-rings 52, 52 are attached to both ends in the axial direction. Here, each O-ring 52 is in sliding contact with the inner peripheral surface of the sleeve 5 and
The sleeve 5 and the like together with the grease G filled in A are smoothly rotated with respect to the fixed shaft 51.

Thus, in the present embodiment having the above-described structure, substantially the same operation and effect as those of the first embodiment can be obtained. In the present embodiment, in particular, each O.D.
Since the ring 52 is mounted, it is possible to prevent the grease G in the circumferential groove 51A from leaking to the outside from between the fixed shaft 51 and the sleeve 5 for a long time.

In each of the above embodiments, the fixed shaft 31 (41, 51)
It is described that the circumferential groove 31A (41A, 51A) is provided on the outer periphery of the sleeve 5 and the grease reservoir is formed between the sleeve 5 and the grease reservoir. Instead, an annular groove as the grease reservoir is provided on the inner periphery of the sleeve 5. Of course, it may be formed.

In the above embodiment, the sleeve 5 is formed separately from the resin mold portion 8 of the rotor 6. However, the sleeve 5 is replaced with the boss portion 8 of the resin mold portion 8.
It may be formed integrally with A, 8B or the like.

Furthermore, in each of the above embodiments, the case where the damping force of the damping force adjusting type hydraulic shock absorber is adjusted in two stages of hardware and software has been described as an example, but the present invention is not limited to this, and the damping force is not limited to this. The present invention may be applied to a rotary actuator adjusted in three or more stages, and it is needless to say that the rotary actuator may be used for something other than the hydraulic shock absorber.

〔The invention's effect〕

As described in detail above, according to the present invention, an annular grease reservoir is formed between the fixed shaft and the sleeve, and the grease reservoir is filled with grease. An oil film is formed by grease to give a lubricating effect to both, and the sleeve can be smoothly rotated with the rotor around the fixed shaft.

Then, when the rotation of the rotor is stopped by the stopper, the remaining rotational force (inertial force) of the rotor acts on the sleeve, whereby the clearance between the sleeve and the fixed shaft is partially reduced. Even when the sleeve is eccentric with respect to the fixed shaft and the inner peripheral side of the sleeve attempts to collide with the outer peripheral portion of the fixed shaft, the grease filled in the annular grease reservoir has a buffer action between the fixed shaft and the sleeve. By demonstrating,
It is possible to suppress the inner peripheral side of the sleeve from colliding with the outer peripheral side portion of the fixed shaft, and it is possible to reliably reduce the generation of abnormal noise such as interference noise.

[Brief description of the drawings]

1 and 2 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of a rotary actuator, and FIG. 2 is a transverse section of a sleeve and a fixed shaft shown in FIG. FIG. 3, FIG. 3 is a longitudinal sectional view of a sleeve and a fixed shaft showing a second embodiment, FIG. 4 is a longitudinal sectional view similar to FIG. 3, showing a third embodiment, FIG. 5 and FIG. Indicates conventional technology,
FIG. 5 is a longitudinal sectional view of a main part of the rotary actuator, and FIG.
The figure is a bottom view of FIG. 5 showing the bottom plate in a partially broken state. 1 ... casing, 2 ... case, 3 ... bottom plate, 5 ...
Sleeve, 6 Rotor, 7 Core, 8 Resin mold, 9 Coil, 11 Brush, 18 Stator,
21 …… Output shaft, 31,41,51 …… Fixed shaft, 31A, 41A, 51
A: circumferential groove (grease reservoir), 52: O-ring, G:
Grease.

Claims (1)

(57) [Claims] 1. A casing having a cover, a fixed shaft fixed to the casing by cantilever support, and extending in the casing in an axial direction; a sleeve rotatably fitted around an outer periphery of the fixed shaft; A rotor provided so as to be integrally rotatable with the sleeve, a stator provided on the casing at a position radially outward of the rotor, and provided on the rotor and the casing, respectively. In a rotary actuator comprising a stopper for regulating a rotational position,
A rotary actuator, wherein an annular grease reservoir filled with grease is formed between the fixed shaft and the sleeve.