WO2016186001A1

WO2016186001A1 - Electric linear actuator and electric braking device

Info

Publication number: WO2016186001A1
Application number: PCT/JP2016/064166
Authority: WO
Inventors: 山崎　達也
Original assignee: Ntn株式会社
Priority date: 2015-05-19
Filing date: 2016-05-12
Publication date: 2016-11-24
Also published as: JP2016217420A

Abstract

An outer ring member (21) is incorporated in a housing (20), and a rotary shaft (34) that is rotationally driven by an electric motor (24) is provided on the center axis of the outer ring member (21). A planetary roller (49) is incorporated between the rotary shaft (34) and the outer ring member (21). The planetary roller (49) is rotated and revolved by contact with the rotary shaft (34), and the outer ring member (21) is moved in the axial direction by way of spiral projections (57) provided on the inner circumference of the outer ring member (21) engaging with circumferential grooves (58) formed on the outer circumference of the planetary roller (49). The shaft end of a roller shaft (47) that rotatably supports the planetary roller (49) is supported, so as to move freely, in the radial direction by discs (41a, 41b) of a carrier (40), and the shaft end of the roller shaft (47) is biased radially inward by an elastic ring (50) that spans the shaft end so as to encompass the same. The roller shaft (47) is prevented from rotating by way of a roller shaft rotation stop means (54), thereby preventing the roller shaft (47) from rotating along with the planetary roller (49) that rotates and revolves when the planetary roller is rotating.

Description

Electric linear actuator and electric brake device

The present invention relates to an electric linear actuator that linearly drives a driven member such as a brake pad, and an electric brake device using the electric linear actuator.

Conventionally, an electric linear actuator that converts rotational motion of a rotor shaft of an electric motor into linear motion of a driven member that is supported so as to be movable in the axial direction by a motion conversion mechanism has been described in Patent Document 1 below. Are known.

In the electric linear actuator described in Patent Document 1, a plurality of planetary rollers are incorporated between a rotating shaft and an outer ring member that are rotationally driven by an electric motor, and the planetary rollers are rotatable about the rotating shaft. Or a helical groove formed on the outer diameter surface of the planetary roller, revolving while rotating the planetary shaft by frictional contact with the rotation shaft. The outer ring member or the carrier is linearly moved in the axial direction relatively by meshing with the circumferential groove and the spiral protrusion provided on the inner diameter surface of the outer ring member.

Here, the carrier is composed of a pair of disks and a plurality of pillar members that hold the opposed spaces between the disks, and the shaft insertion holes formed in the pair of disks are elongated holes in the radial direction. Both end portions of the roller shaft are movably supported in the radial direction by the shaft insertion holes, and the planetary roller is rotatably supported by the roller shaft.

Further, an elastic ring is wound around the outer periphery of the shaft end portion of the plurality of roller shafts, and each of the plurality of planetary rollers is brought into pressure contact with the outer periphery of the rotating shaft by urging the roller shaft radially inward. Yes.

In the electric linear actuator, the outer ring member or the carrier is relatively linearly moved in the axial direction by meshing between the spiral groove or circumferential groove provided on the planetary roller and the spiral protrusion provided on the outer ring member. Therefore, it is possible to ensure a large boosting function without separately incorporating a planetary gear type reduction mechanism, and it is suitable for use in an electric brake device having a relatively small linear motion stroke. Yes.

In addition, the elastic ring urges the roller shaft radially inward so that the planetary roller is pressed against the outer diameter surface of the rotating shaft, so that the planetary roller is reliably rotated by frictional contact with the rotating shaft. It also has the feature that it can be made to.

However, since an inexpensive C-shaped ring that is easily available is used as the elastic ring, there are the following problems.

That is, since the C-shaped ring is partly cut off in the circumferential direction, when the plurality of roller shafts rotate even slightly with the rotation of the planetary roller, the C-shaped ring is contacted with the roller shaft and the plurality of rollers are rotated. It will rotate in the circumscribed circle direction of the shaft.

Then, when the C-shaped ring comes into contact with and rotates to the position where the separation part of the C-shaped ring faces one of the plurality of roller shafts in the radial direction, the roller shaft fits into the separation part, and the C-shaped ring becomes self-elastic. Reduce diameter. Due to the reduced diameter, the contact pressure of the planetary roller with respect to the outer diameter surface of the rotating shaft is released, the rotation of the rotating shaft cannot be transmitted to the planetary roller, and the rotating shaft is idled to operate the electric linear actuator. Can not be.

In order to solve the above-mentioned problem, the applicant of the present invention in Patent Document 2 provides a rotation preventing means between the C-shaped ring and the plurality of roller shafts, and the C-shaped ring is made up of the plurality of roller shafts by the rotation preventing means. There has already been proposed an electric linear actuator that prevents relative rotation in the circumscribed circle direction.

As described above, by rotating the C-shaped ring, the plurality of planetary rollers are always held in pressure contact with the outer diameter surface of the rotating shaft by the C-shaped ring. Transmission to each of the planetary rollers can be ensured, and the electric linear actuator can be made to function reliably.

JP 2012-149747 A JP 2012-175772 A

By the way, in the electric linear actuator described in Patent Document 2, a needle roller bearing, a sliding bearing made of a sintered material, or the like between a planetary roller and a roller shaft that supports the planetary roller. The planetary roller is rotatably supported by incorporating this bearing, but the rolling resistance and sliding resistance increase as the lubricant enclosed in the bearing deteriorates and the viscosity resistance increases at low temperatures. It is conceivable that the roller shaft rotates with the rotation of the roller.

Here, when the roller shaft rotates, the C-shaped ring that urges the roller shaft radially inward is prevented from rotating, so that wear due to relative sliding occurs at the contact portion between the C-shaped ring and the roller shaft. The elastic force of the C-shaped ring is reduced. As the elastic force decreases, the contact pressure of the planetary roller with respect to the rotating shaft decreases, causing relative slippage at the contact portion, causing the rotating shaft to idle, causing power transmission failure, and the electric linear actuator not functioning. Can be considered.

An object of the present invention is to prevent the occurrence of troubles such as poor power transmission caused by the rotation of the roller shaft.

In order to solve the above problems, in the electric linear actuator according to the present invention, a cylindrical outer ring member is incorporated in the housing, and a rotary shaft driven by an electric motor is provided on the axis of the outer ring member. A plurality of planetary rollers are incorporated between the outer diameter surface of the rotating shaft and the inner diameter surface of the outer ring member, and both end portions of the roller shaft that rotatably supports each planetary roller are rotatably supported around the rotating shaft. A plurality of roller shafts are supported by a pair of opposed discs of the carrier formed so as to be movable in the radial direction, and an elastic ring having a cut-off portion at a part in the circumferential direction is wound around the shaft end portion of each roller shaft. Each of the planetary rollers is urged radially inward, and a spiral groove or a circumferential groove is formed on each outer diameter surface of the planetary roller to mesh with a spiral protrusion provided on the inner diameter surface of the outer ring member. In the electric linear actuator that rotates and revolves a plurality of planetary rollers by frictional contact with the rotation shaft and rotates the outer ring member and the carrier relatively in the axial direction by rotation of the rotation shaft, A configuration is adopted in which a plurality of roller shafts are provided with roller shaft detent means for preventing the roller shafts from rotating while allowing movement in the radial direction.

As described above, each of the plurality of roller shafts that rotatably support the planetary roller is prevented from rotating in a state in which it can move in the radial direction, so that the planetary roller that rotates by contact with the rotation shaft can rotate. The roller shaft can be prevented from rotating together.

As a result, wear occurs at the contact portion between the elastic ring that urges the roller shaft radially inward and the roller shaft, the elastic force of the elastic ring decreases, and the contact pressure of the planetary roller against the rotating shaft decreases. There is no inconvenience. For this reason, the planetary roller reliably rotates in contact with the rotation of the rotation shaft, and it is possible to prevent troubles such as power transmission failure caused by the rotation of the roller shaft.

Here, the roller shaft detent means may be provided between the roller shaft and the carrier, or may be provided between the roller shaft and the elastic ring. When a roller shaft detent means is provided between the roller shaft and the carrier, a flat surface is provided on the outer periphery of the shaft end of the roller shaft, and the roller shaft is formed on the disk of the carrier and is elongated in the radial direction through which the roller shaft is inserted. An engaging surface that engages with the flat surface is provided on the inner periphery of the extending shaft insertion hole.

On the other hand, when the roller shaft detent means is provided between the roller shaft and the elastic ring, a fitting groove into which a part of the inner periphery of the elastic ring is fitted is provided in a part of the outer periphery of the shaft end of the roller shaft. At least both end portions of the bottom surface of the fitting groove are engaged with the inner diameter surface of the elastic ring.

In the case where a roller shaft detent means is provided between the roller shaft and the elastic ring, a diameter expansion prevention ring for preventing the elastic ring from expanding in an interior part that is incorporated inside the outer ring member and disposed opposite to the carrier. It is good to provide a part.

As described above, by providing the diameter expansion prevention ring portion, the diameter expansion of the elastic ring can be prevented, so that the roller shaft can be reliably prevented from rotating.

In the electric brake device according to the present invention, the brake pad is linearly driven by the electric linear actuator, the disk rotor is pressed by the brake pad, and a braking force is applied to the disk rotor. In the apparatus, a configuration using the electric linear actuator according to the above-described invention is adopted as the electric linear actuator.

In the electric linear actuator having the above configuration, when the rotating shaft is rotated by driving the electric motor, the planetary roller revolves while rotating by frictional contact with the rotating shaft, and is formed on the outer diameter surface of the planetary roller. The outer ring member or the carrier relatively linearly moves in the axial direction by meshing of the spiral groove or the circumferential groove and the spiral protrusion provided on the inner diameter surface of the outer ring member.

Therefore, by connecting the brake pad of the electric brake device to the outer ring member or the carrier, the brake pad can be linearly driven and pressed against the disc rotor, and a braking force can be applied to the disc rotor.

In the electric linear actuator according to the present invention, as described above, each of the plurality of roller shafts rotatably supporting the planetary roller is rotated in a state in which the roller shaft can be moved in the radial direction by the rotation preventing means. By stopping, it is possible to prevent the roller shaft from rotating when the planetary roller that rotates by contact with the rotation shaft rotates, and troubles such as poor power transmission caused by the rotation of the roller shaft can be prevented. Occurrence can be prevented in advance.

A longitudinal sectional view showing an embodiment of an electric linear actuator according to the present invention Sectional drawing which expands and shows a part of FIG. Sectional view along line III-III in FIG. Sectional view along line IV-IV in FIG. Sectional drawing which expands and shows a part of FIG. Front view of roller shaft Plan view of FIG. 6A Sectional view along line VI-VI in FIG. 6A Sectional view showing another example of roller shaft Sectional drawing which shows the other example of the roller shaft detent | locking means which stops a roller shaft Sectional view along line IX-IX in FIG. A longitudinal sectional view showing an embodiment of an electric brake device according to the present invention Right side view of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 6C show an electric linear actuator A employed in the electric brake device shown in FIGS. 10 and 11.

In the electric brake device shown in FIGS. 10 and 11, a caliper 11 is provided on the outer periphery of the disk rotor 10 that rotates integrally with a wheel (not shown), and the outer periphery of the outer side surface of the disk rotor 10 is provided at one end of the caliper 11. The claw part 12 which opposes a part in an axial direction is provided, and the outer side brake pad 13 is supported by the claw part 12.

Further, an inner brake pad 14 is disposed opposite to the outer peripheral portion of the inner side surface of the disk rotor 10, and the inner brake pad 14 is attached to the disk rotor 10 by an electric linear actuator A provided on the other side of the caliper 11. I try to move it.

A mount 15 is provided on the outer periphery of the inner side surface of the disk rotor 10. The mount 15 is fixedly supported by a knuckle (not shown). A pair of opposed pin support pieces 16 are provided on both sides of the mount 15, and slide pins 17 extending in a direction orthogonal to the disk rotor 10 are provided at the respective ends of the pin support pieces 16. The caliper 11 is slidably supported by each.

Although not shown in detail in the figure, the mount 15 is supported so as to be movable toward the disc rotor 10 in a state in which each of the outer brake pad 13 and the inner brake pad 14 is non-rotatable. is doing.

As shown in FIG. 1, the electric linear actuator A has a housing 20. The housing 20 is provided integrally with the caliper 11 shown in FIG. 10 to form a cylinder, and a cylindrical outer ring member 21 is slidably incorporated therein.

A base plate 22 is provided at one end of the housing 20 outward in the radial direction. The outer surface of the base plate 22 and one end opening of the housing 20 are covered with a cover 23, and the base plate 22 and the cover 23 form a gear case. Forming.

The electric motor 24 is supported on the base plate 22, and the rotation of the rotor shaft 25 of the electric motor 24 is decelerated and output by a gear reduction mechanism 30 in a gear case formed by the base plate 22 and the cover 23.

As shown in FIGS. 1 and 11, the gear reduction mechanism 30 includes an input gear 31 attached to the rotor shaft 25 of the electric motor 24, an intermediate gear 32 that meshes with the input gear 31, and meshes with the intermediate gear 32. Output gear 33.

As shown in FIG. 1, the output gear 33 is supported by one end of the rotating shaft 34. The rotating shaft 34 passes through a shaft support member 35 incorporated in one end portion of the housing 20 and is rotatably supported by a plurality of bearings 36 incorporated in the penetrating portion so as to be coaxial with the outer ring member 21. Yes.

Here, the shaft support member 35 has an outer diameter surface supported by the inner diameter surface of the housing 20, a retaining ring 37 attached to the inner diameter surface of the housing 20, and an inwardly provided at one end portion of the housing 20. The flange 38 is positioned in the axial direction.

As shown in FIGS. 1 and 2, a carrier 40 that can rotate within the outer ring member 21 around the rotation shaft 34 is incorporated on the rotation shaft 34. As shown in FIG. 2, the carrier 40 has a pair of

discs

41a and 41b facing each other in the axial direction, and one of the outer side discs 41b is provided with a plurality of column members 42 for maintaining the interval. The members 42 are brought into contact with the inner surface of the inner disk 41 a and are connected to each other by tightening screws 43 screwed into the end surfaces of the column members 42 from the outer surface of the inner disk 41 a to assemble the carrier 40.

Here, as shown in FIG. 3, the number of the column members 42 of the carrier 40 is four, and the four column members 42 are provided at intervals of 90 ° in the circumferential direction. Is not limited to four, but may be at least three.

As shown in FIG. 2, the carrier 40 is rotatably supported around a rotating shaft 34 by a slide bearing 44 incorporated in each of the inner diameter surfaces of the pair of

disks

41 a and 41 b, and the shaft end of the rotating shaft 34. The retaining ring 45 attached to the section prevents the shaft from rotating from the shaft end.

The pair of

discs

41a and 41b in the carrier 40 are formed with a plurality of axial insertion holes 46 that are opposed in the axial direction at intervals in the circumferential direction. A shaft end portion of a roller shaft 47 is inserted into each of the plurality of opposed shaft insertion holes 46, and a planetary roller 49 is rotatably supported on each roller shaft 47 via a plurality of bearings 48. As the bearing 48, a rolling bearing such as a needle roller bearing or a sliding bearing can be employed.

Here, the shaft insertion holes 46 formed in the pair of

disks

41a and 41b are long holes in the radial direction. The roller shaft 47 is movable within a range in contact with both ends of the shaft insertion hole 46 formed of a long hole, and can be elastically deformed in the radial direction spanned around the shaft end portion of each roller shaft 47. Each of the roller shafts 47 is urged inward by the elastic ring 50, and the planetary roller 49 is pressed against the outer diameter surface of the rotating shaft 34. For this reason, when the rotating shaft 34 rotates, the planetary roller 49 rotates by frictional contact with the outer diameter surface of the rotating shaft 34.

As shown in FIGS. 2 and 4, the elastic ring 50 is formed of a C-shaped ring having a rectangular cross section having a cut-off portion at a part in the circumferential direction. As shown in FIGS. 4 and 5, the elastic ring 50 prevents a part of the inner periphery from engaging with the ring groove 51 formed at the shaft end portion of the roller shaft 47 and coming out of the shaft end of the roller shaft 47. Has been.

As shown in FIG. 4, between the elastic ring 50 and the plurality of roller shafts 47, there is provided a ring detent means 52 for preventing the elastic ring 50 from rotating relative to the circumscribed circle direction of the plurality of roller shafts 47. It has been. Here, as the ring detent means 52, inwardly bent pieces 53 are provided at both ends of the cut-off portion of the elastic ring 50, and the bent pieces 53 are disposed between a pair of adjacent roller shafts 47. The elastic ring 50 is prevented from rotating by the contact of the bent piece 53 with the roller shaft 47.

As shown in FIGS. 2, 4, and 5, each of the plurality of roller shafts 47 rotates around the shaft center by a roller shaft detent means 54 provided between the shaft insertion hole 46 of the carrier 40. Is prevented. As shown in FIGS. 5 and 6A to 6C, the roller shaft detent means 54 is provided with a pair of flat surfaces 55 at positions facing the outer periphery of the shaft end of the roller shaft 47, while a pair of disks 41a in the carrier 40 is provided. A pair of engaging surfaces 56 are provided at positions opposed to the inner periphery of the shaft insertion hole 46 formed in the shaft 41b, and the pair of engaging surfaces 56 are surface-engaged with the pair of flat surfaces 55, respectively. .

5 and 6A to 6C, the flat surface 55 and the engagement surface 56 are each paired. However, as shown in FIG. 7, the flat surface 55 and the engagement surface 56 should be at least one. Good.

As shown in FIG. 2, a plurality of circumferential grooves 58 are formed on the outer diameter surface of the planetary roller 49 at the same pitch as the pitch of the spiral protrusions 57 having a V-shaped cross section provided on the outer ring member 21. A spiral ridge 57 meshes with the circumferential groove 58. In place of the circumferential groove 58, a spiral groove having a lead angle different from that of the spiral protrusion 57 and having the same pitch may be formed.

Of the pair of

disks

41a and 41b in the carrier 40, the inner disk 41a located on the shaft support member 35 (see FIG. 1) side and the planetary roller 49 are arranged in the axial direction from the planetary roller 49 side in order. A thrust bearing 59, a pressure seat plate 60, and a pressure receiving seat plate 61 are incorporated, and the pressure seat plate 60 and the pressure receiving seat plate 61 are in contact via a spherical seat 62. Further, a gap is provided between the fitting surfaces of the pressure receiving seat plate 61 and the roller shaft 47, and the roller shaft 47 and the pressure seat plate 60 can be freely adjusted within the range of the gap.

As shown in FIG. 1, a backup plate 63 and a thrust bearing 64 as interior parts are incorporated between the inner side disk 41 a and the aforementioned shaft support member 35 that rotatably supports the rotating shaft 34, and from the outer ring member 21. An axial reaction force applied to the carrier 40 via the planetary roller 49 is supported by the thrust bearing 64.

As shown in FIG. 2, the backup plate 63 is provided with a diameter expansion prevention ring portion 63 a on the outer peripheral portion of the surface facing the elastic ring 50, and the diameter expansion prevention ring portion 63 a covers the outer periphery of the elastic ring 50. Thus, the elastic ring 50 is prevented from expanding in diameter.

A cover 65 is fitted in the outer side end portion of the outer ring member 21. An anti-rotation groove 66 is formed on the front end surface of the cover 65, and an anti-rotation protrusion 19 provided on the pad holder 18 of the inner brake pad 14 shown in FIG. Thus, the outer ring member 21 is prevented from rotating with respect to the inner brake pad 14.

Here, since the pad holder 18 is supported by the mount 15 so as to be movable in the axial direction and is prevented from rotating, the outer ring member 21 is prevented from rotating with respect to the housing 20 and supported so as to be movable in the axial direction. It is said that.

As shown in FIG. 10, a boot 68 is attached between the outer end of the housing 20 and the outer ring member 21, and the boot 68 seals between the outer end of the housing 20 and the tip of the outer ring member 21. ing.

The electric brake device shown in the embodiment has the above-described configuration. FIG. 10 shows a state in which the braking force is released from the disk rotor 10, and the pair of

brake pads

13 and 14 are separated from the disk rotor 10. .

When the electric motor 24 shown in FIG. 1 is driven in the state in which the braking force is released as described above, the rotation of the rotor shaft 25 of the electric motor 24 is decelerated by the gear reduction mechanism 30 and transmitted to the rotating shaft 34, and the rotating shaft 34 rotates in the braking direction.

Since the outer diameter surfaces of the plurality of planetary rollers 49 are in elastic contact with the outer diameter surface of the rotating shaft 34, the planetary roller 49 rotates due to contact friction with the rotating shaft 34 due to the rotation of the rotating shaft 34. While revolving.

At this time, since the circumferential groove 58 formed on the outer diameter surface of the planetary roller 49 meshes with the spiral protrusion 57 provided on the inner diameter surface of the outer ring member 21, the circumferential groove 58 and the spiral protrusion 57. 10, the outer ring member 21 moves in the axial direction, and as shown in FIG. 10, the inner brake pad 14 abutted on the outer ring member 21 abuts on the disk rotor 10, and the disk rotor 10 is axially moved. Begin to press on. The caliper 11 moves toward the direction in which the outer brake pad 13 supported by the claw portion 12 approaches the disc rotor 10 by the reaction force of the pressing force, and the outer brake pad 13 contacts the disc rotor 10, The outer brake pad 13 strongly clamps the outer periphery of the disk rotor 10 from both sides in the axial direction with the inner brake pad 14, and a braking force is applied to the disk rotor 10.

When the braking force is applied as described above, an axial load is applied from the outer ring member 21 to the planetary roller 49. The input portion of the axial load is an engaging portion of a spiral protrusion 57 provided on the inner diameter surface of the outer ring member 21 and a circumferential groove 58 formed on the outer diameter surface of the planetary roller 49. An unbalanced load is applied to.

At this time, a pressure seat plate 60 and a pressure receiving seat plate 61 are assembled between the planetary roller 49 and the inner disk 41a of the carrier 40, and a spherical seat 62 (see FIG. 2) is formed on the opposing surface of the both

seat plates

60, 61. Therefore, as described above, when an eccentric load is applied to the planetary roller 49, the pressure seat 60 is tilted in a state where the pressure seat 60 is brought into contact with the spherical seat 62, and the pressure seat 60. Therefore, the surface pressure distribution in the circumferential direction is made uniform at the contact portion of the pressure receiving seat plate 61.

For this reason, the axial load of the same magnitude is applied to the thrust bearing 59 over the entire circumferential direction, and there is no inconvenience that the raceway surface and the rolling element are unevenly worn.

When the rotor shaft 25 of the electric motor 24 is reversely rotated after the disk rotor 10 is braked, the rotating shaft 34 shown in FIG. 1 is decelerated and rotated in the reverse direction to the above, and the circumferential groove 58 of the planetary roller 49 that revolves while rotating. The outer ring member 21 is moved backward to the position shown in FIG. 10 by the engagement of the spiral protrusion 57 and the outer brake pad 13 and the inner brake pad 14 release the disc rotor 10 to release the braking force. The

In the electric linear actuator shown in the embodiment, as shown in FIG. 2, a bearing 48 is incorporated between a planetary roller 49 and a roller shaft 47 that supports the planetary roller 49 so that the planetary roller 49 can rotate freely. Although supported, there is a possibility that the roller shaft 47 rotates with the deterioration of the lubricant in the bearing 48 and the increase in viscous resistance at low temperatures.

Here, if the roller shaft 47 rotates in a series, wear due to relative sliding occurs at the contact portion between the elastic ring 50 and the roller shaft 47 that are prevented from rotating by the ring detent means 52 shown in FIG. Power is reduced. As the elastic force decreases, the contact pressure of the planetary roller 49 with respect to the rotating shaft 34 decreases, relative slip occurs at the contact portion, the rotating shaft 34 idles, power transmission failure occurs, and the electric linear actuator functions. No longer.

However, in the embodiment, as shown in FIG. 5, the engagement surface 56 provided on the inner periphery of the shaft insertion hole 46 that supports the roller shaft 47 movably in the radial direction is provided at the shaft end portion of the roller shaft 47. Since the roller shaft 47 is prevented from rotating by the roller shaft rotation preventing means 54 that is in surface engagement with the flat surface 55 formed on the outer periphery, the roller shaft 47 is rotated when the planetary roller 49 that rotates by contact with the rotating shaft 34 rotates. Can be prevented from being carried around. As a result, it is possible to prevent the occurrence of troubles such as power transmission failure caused by the rotation of the roller shaft 47.

In FIG. 5, the roller shaft detent means 54 is formed by surface engagement between a flat surface 55 formed on the outer periphery of the shaft end portion of the roller shaft 47 and an engagement surface 56 provided on the inner periphery of the shaft insertion hole 46. Although shown, the roller shaft detent means 54 is not limited to this.

8 and 9 show another example of the roller shaft detent means 54. FIG. In this example, a fitting groove 70 into which a part of the inner periphery of the elastic ring 50 is fitted is provided at a part of the outer circumference of the shaft end of the roller shaft 47, and both ends of the flat groove bottom surface 70a in the fitting groove 70 are provided. The roller shaft 47 is prevented from rotating by engaging with the inner diameter surface of the elastic ring 50.

The groove bottom surface 70a of the fitting groove 70 may be an arc surface along the inner diameter surface of the elastic ring 50, and the entire surface of the groove bottom surface 70a may be engaged with the inner diameter surface of the elastic ring 50. Alternatively, both ends may be engaged with the inner diameter surface of the elastic ring 50 as a concave curved surface.

As shown in FIG. 8, when the diameter expansion prevention ring portion 63a is provided in the backup plate 63 as the interior part, the diameter expansion prevention ring portion 63a can prevent the elastic ring 50 from expanding. The roller shaft 47 can be reliably prevented from rotating.

The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. The scope of the present invention is defined by the terms of the claims, and includes meanings equivalent to the description of the claims and all modifications within the scope.

A Electric linear actuator 10 Disc rotor 14 Brake pad 20 Housing 21 Outer ring member 24 Electric motor 34 Rotating shaft 40 Carrier 41a Disc 41b Disc 47 Roller shaft 49 Planetary roller 50 Elastic ring 52 Ring detent means 54 Roller axis detent means 55 Flat surface 56 Engagement surface 57 Spiral ridge 58 Circumferential groove 63 Backup plate (interior part)
63a Diameter expansion prevention ring part 65 Cover (interior part)
70 Fitting groove 70a Groove bottom

Claims

A cylindrical outer ring member is incorporated in the housing, a rotation shaft driven by an electric motor is provided on the axis of the outer ring member, and a plurality of planetary rollers are provided between the outer diameter surface of the rotation shaft and the inner diameter surface of the outer ring member. The both ends of the roller shaft that rotatably supports each planetary roller are supported by a pair of opposing disks of a carrier that is rotatably supported around the rotation shaft, and can be moved in the radial direction. An elastic ring having a cut-out portion at a part of the roller shaft is wound around the shaft end portion of each roller shaft to urge each of the plurality of roller shafts radially inwardly, A spiral groove or a circumferential groove that meshes with a spiral protrusion provided on the inner diameter surface of the outer ring member is formed on the radial surface, and rotation of the rotation shaft causes a plurality of planetary rollers to rotate by frictional contact with the rotation shaft. Oh By finely revolution in electric linear motion actuator adapted to move the outer ring member and the carrier relative axial,
An electric linear actuator comprising a roller shaft detent means for preventing the plurality of roller shafts from rotating in a state of permitting movement in a radial direction.
The roller shaft detent means has a flat surface on the outer periphery of the shaft end of the roller shaft, and is formed on the inner periphery of a shaft insertion hole formed on the carrier disk and extending in the radial direction through which the roller shaft is inserted. The electric linear motion actuator according to claim 1, comprising an engagement surface that is surface-engaged with a flat surface.
The roller shaft detent means has a fitting groove in which a part of the inner periphery of the elastic ring is fitted in a part of the outer periphery of the shaft end of the roller shaft, and at least both ends of the groove bottom surface in the fitting groove are The electric linear actuator according to claim 1, wherein the electric linear actuator is configured to be engaged with an inner diameter surface of the elastic ring.
The electric linear actuator according to claim 3, wherein a diameter expansion prevention ring portion for preventing the diameter expansion of the elastic ring is provided in an interior part that is incorporated inside the outer ring member and is disposed to face the carrier.
In the electric brake device in which the brake pad is linearly driven by the electric linear actuator, the brake pad is pressed against the disc rotor, and braking force is applied to the disc rotor.
The electric brake apparatus, wherein the electric linear actuator comprises the electric linear actuator according to any one of claims 1 to 4.