JP6407704B2 - Electric linear actuator and electric brake device - Google Patents

Description

  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 driven by an electric motor and an outer ring member, and the planetary rollers are rotated around the rotating shaft. A spiral groove formed on the outer diameter surface of the planetary roller, which is supported by a freely supported carrier and revolves while the planetary roller rotates and rotates by frictional contact with the rotation shaft. Alternatively, the outer ring member or the carrier is relatively linearly moved in the axial direction by meshing with the circumferential groove and the spiral protrusion provided on the inner diameter surface of the outer ring member.

  Further, a thrust roller bearing is incorporated between opposing surfaces of one of a pair of disks forming a carrier with each of the plurality of planetary rollers, and the thrust load applied to the planetary roller is supported by the thrust roller bearing, the planetary roller The rotation resistance is reduced by rotating the motor.

  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.

JP 2010-90959 A

  By the way, in the electric linear actuator described in Patent Document 1, the thrust roller bearing that rotatably supports each of the plurality of planetary rollers is a thrust cage roller that holds the plurality of thrust rollers radially by a cage. And a single washer, and the thrust cage roller and washer must be assembled separately for each roller shaft that rotatably supports the planetary roller. In addition, there is a possibility that an assembly position may be mistaken or forgotten to be assembled due to an incorrect assembly order.

  An object of the present invention is to reduce the number of parts of a thrust roller bearing and to facilitate the assembly of a carrier that supports a planetary roller.

  In order to solve the above-mentioned problems, in the first invention, a cylindrical outer ring member is incorporated in the housing, and a rotary shaft that is rotationally driven by an electric motor is provided on the axis of the outer ring member. A plurality of planetary rollers incorporated between an outer diameter surface and an inner diameter surface of the outer ring member are rotatably supported by a carrier that is rotatably supported around the rotation axis. 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, and a load is applied to the planetary roller between each of the planetary rollers and the opposing surface of the disk provided on the carrier. A thrust retainer roller for supporting a thrust load to be generated, and the outer ring member and the carrier by rotating and revolving the planetary roller by frictional contact with the rotation shaft by rotation of the rotation shaft In the electric linear actuator that is linearly moved relatively in the axial direction, an annular washer common to each of the plurality of thrust cage rollers is provided between the opposing surfaces of the plurality of thrust cage rollers and the disk. The built-in configuration was adopted.

  In the electric linear actuator with the above configuration, the bearing disc is molded by plastic processing of metal members to reduce costs, and the raceway surface facing the thrust cage roller is heat treated to increase hardness and improve durability. It is good to plan.

  In the second invention, the annular washer according to the first invention is omitted, and the inner surface of the carrier facing the thrust retainer roller of the disk is common to each of the plurality of thrust retainer rollers. This is the configuration used.

  In the electric linear actuator according to the second aspect of the invention, the disk is formed by plastic working of a metal member, and the raceway surface that rolls and guides the roller of the thrust cage roller is heat treated to increase the hardness and improve the durability. It is good to plan.

  Furthermore, in the third aspect of the invention, in the electric brake device in which the brake pad is linearly driven by the electric linear actuator, and the disc rotor is pressed by the brake pad to apply a braking force to the disc rotor. The configuration using the electric linear actuator according to the first or second invention is employed 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.

  For this reason, 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 disk rotor, and a braking force can be applied to the disk rotor.

  As in the first invention, the annular washer is common to each of the plurality of thrust cage rollers, or, as in the second invention, the inner side surface of the carrier facing the thrust cage roller is a plurality of By using a common raceway surface for each of the thrust cage rollers, the number of parts of the thrust roller bearing can be reduced, the assembly of the carrier can be facilitated, and erroneous assembly of parts or forgetting to install can be prevented.

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. Front view showing thrust cage rollers Sectional drawing which expands and shows the installation part of the common washer of FIG. Sectional drawing which shows other embodiment of the electrically driven linear actuator which concerns on this invention 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 6 show an electric linear actuator A employed in the electric brake device shown in FIGS. 8 and 9.

  In the electric brake device shown in FIGS. 8 and 9, a caliper 11 is provided on the outer periphery of the disc rotor 10 that rotates integrally with a wheel (not shown), and the outer periphery of the outer side surface of the disc 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. doing.

  As shown in FIG. 1, the electric linear actuator A has a housing 20. The housing 20 is integrally provided with the caliper 11 shown in FIG. 8 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.

  An 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 9, 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. The outer diameter of the output gear 33 is larger than the outer diameter of the input gear 31.

  As shown in FIG. 1, the output gear 33 is supported at 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 is positioned in the axial direction by a retaining ring 37 attached to the inner diameter surface of the housing 20 and an inward flange 38 provided at one end of the housing 20.

  As shown in FIGS. 1 and 2, a carrier 40 that is rotatable within the outer ring member 21 around the rotation shaft 34 is incorporated on the rotation shaft 34. As shown in FIGS. 2 and 3, the carrier 40 includes a pair of discs 41 a and 41 b that are opposed in the axial direction, and a plurality of column members 42 that maintain a constant spacing between the discs 41 a and 41 b.

  Each of the pair of disks 41a and 41b is formed with a plurality of axially opposed pair of connection holes 43 at equal intervals in the circumferential direction, and both end portions of the column member 42 are connected to the pair of connection holes 43 opposed in the axial direction. Are fitted with a negative fitting gap. That is, both end portions of the column member 42 are press-fitted and fitted into the connection holes 43, and the discs 41 a and 41 b and the column member 42 are connected to each other by the press-fitting to assemble the carrier 40.

  Here, as shown in FIG. 3, the number of column members 42 is four, and the four column members 42 are provided at intervals of 90 ° in the circumferential direction, but the number of the column members 42 is four. It is not limited to, and it is sufficient that there are at least three or more.

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

  In each of the pair of disks 41 a and 41 b in the carrier 40, a pair of shaft insertion holes 46 opposed in the axial direction are formed at intervals in the circumferential direction. A shaft end portion of the roller shaft 47 is inserted into each of the pair of opposed shaft insertion holes 46, and a pair of opposed bearings 48 are fitted to the respective roller shafts 47, and the planetary roller 49 is rotatably supported by the bearings 48. Has been.

  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 in a range where it abuts on both ends of the long hole, and the roller shaft 47 is elastically deformed in the radial direction so as to wrap around the shaft end portion of each roller shaft 47. The planetary roller 49 is pressed against the outer diameter surface of the rotary shaft 34 by being biased inward. 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 3, a plurality of circumferential grooves 52 are formed on the outer diameter surface of the planetary roller 49 at the same pitch as the pitch of the spiral protrusions 51 having a V-shaped cross section provided on the outer ring member 21. The spiral protrusion 51 is formed in the circumferential groove 52. In place of the circumferential groove 52, a spiral groove having a lead angle different from that of the spiral protrusion 51 and having the same pitch may be formed.

  Among the pair of disks 41a and 41b in the carrier 40, a thrust retainer roller 53 is incorporated between the opposing parts of the inner disk 41a located on the shaft support member 35 side and the plurality of planetary rollers 49.

  As shown in FIGS. 4 to 6, the thrust cage roller 53 has a configuration in which a plurality of pockets 55 extending radially in a radial direction are provided in a cage 54 formed of an annular plate, and a roller 56 is incorporated in each pocket 55. The width of the opening of the pocket 55 is made smaller than the outer diameter of the roller 56 to prevent the roller 56 from being pulled out.

  The end surface 49a of the planetary roller 49 is a raceway surface, and the roller 56 is rolled and guided by the raceway surface 49a. The raceway surface 49a is heat-treated to increase its hardness. The raceway surface 49a is polished so that the surface roughness Ra is 0.2 or less.

  Between the plurality of thrust retainer rollers 53 and the opposed surface of the inner disk 41 a in the carrier 40, a common washer disk 57 is incorporated in each of the plurality of thrust retainer rollers 53.

  The washer disk 57 has an annular shape, and a shaft insertion hole 60 into which each of the plurality of roller shafts 47 is inserted around a center hole 58 through which the rotation shaft 34 is inserted, and each of the plurality of column members 42 of the carrier 40. An insertion hole 61 to be inserted is provided.

  The raceway 57 is formed by plastic working by pressing a metal member, the raceway surface 62 that rolls and guides the roller 56 of the thrust cage roller 53 is heat-treated, and the surface roughness Ra is 0.2 or less.

  As shown in FIG. 1, a backup plate 63 and a thrust bearing 64 are incorporated between the inner side disk 41 a and the above-described shaft support member 35 that rotatably supports the rotation shaft 34 in the carrier 40. An axial reaction force applied to the carrier 40 via the roller 49 is supported by the thrust bearing 64.

  A cover 65 is fitted in the outer side end portion of the outer ring member 21. An anti-rotation groove 66 is formed at the front end surface of the outer ring member 21, and the outer ring member 21 is engaged by the engagement of the anti-rotation groove 66 and the anti-rotation protrusion 19 provided on the back plate 18 of the inner brake pad 14 shown in FIG. 8. Is prevented from rotating with respect to the inner brake pad 14.

  A boot 67 is attached between the outer side end of the housing 20 and the outer ring member 21, and the boot 67 seals between the outer end of the housing 20 and the tip of the outer ring member 21.

  The electric brake device shown in the embodiment has the above-described configuration. FIG. 8 shows a state in which the braking force is released from the disc rotor 10, and the pair of brake pads 13 and 14 are separated from the disc 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 52 formed on the outer diameter surface of the planetary roller 49 meshes with the spiral protrusion 51 provided on the inner diameter surface of the outer ring member 21, the circumferential groove 52 and the spiral protrusion 51. Accordingly, the outer ring member 21 moves in the axial direction, and the inner brake pad 14 in contact with the outer ring member 21 comes into contact with the disk rotor 10 and starts to press the disk rotor 10 in the axial direction. 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, and the axial load is supported by a contact portion between the thrust cage roller 53 and the common washer disk 57. Here, since the roller 56 is guided by rolling by the raceway surface 62 of the common washer 57, the planetary roller 49 always rotates smoothly.

  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 that described above, and the circumferential groove 52 of the planetary roller 49 that revolves while rotating. The outer ring member 21 is moved backward to the position shown in FIG. 8 by the meshing of the spiral protrusions 51, and the outer brake pad 13 and the inner brake pad 14 release the clamping of the disc rotor 10, and the braking force is released. The

  In the electric linear actuator A shown in the embodiment, as shown in FIG. 6, a thrust cage roller 53 is incorporated between the opposing portions of the inner disk 41 a and the plurality of planetary rollers 49 in the carrier 40. A thrust roller bearing that rotatably supports the planetary roller 49 is formed by incorporating a common washer disk 57 in each of the plurality of thrust cage rollers 53 between the opposed surfaces of the plurality of thrust cage rollers 53 and the inner disk 41a. Therefore, the number of parts can be greatly reduced as compared with the case where a thrust roller bearing in which a bearing disc is provided in each of the plurality of thrust cage rollers is employed.

  As a result, the assembly of the carrier 40 can be facilitated, and an effect can be obtained in preventing erroneous assembly of parts forming the thrust roller bearing and forgetting to incorporate it.

  FIG. 7 shows another embodiment of the electric linear actuator. In this embodiment, the common washer disk 57 shown in FIG. 6 is omitted, and the inner surface of the carrier 40 facing the thrust retainer roller 53 of the inner side disk 41a is common to each of the plurality of thrust retainer rollers 53. 6 is different from FIG. For this reason, the same components as those in FIG.

  Here, the disk 41a is formed by plastic working by pressing a metal member, and the raceway surface 68 that rolls and guides the roller 56 of the thrust cage roller 53 is heat treated and polished to have a surface roughness Ra of 0.2 or less. Has been.

  As shown in FIG. 7, the inner surface of the inner disk 41 a facing the thrust cage roller 53 is a common raceway surface 68 for each of the plurality of thrust cage rollers 53, thereby comparing with the one shown in FIG. 6. As a result, the number of parts can be further reduced, the assembly of the carrier 40 can be further facilitated, and an effect can be obtained by preventing erroneous assembly of the parts forming the thrust roller bearing and forgetting to incorporate them.

A Electric linear actuator 10 Disc rotor 13, 14 Brake pad 20 Housing 21 Outer ring member 24 Electric motor 34 Rotating shaft 40 Carrier 41a, 41b Disc 49 Planetary roller 49a End surface (track surface)
51 Helical ridge 52 Circumferential groove 53 Thrust retainer roller 57 Raceway 62 Raceway surface 68 Raceway surface

Claims (5)

A cylindrical outer ring member (21) is incorporated in the housing (20), and a rotary shaft (34) rotated by an electric motor (24) is provided on the axis of the outer ring member (21). A plurality of planetary rollers (49) incorporated between the outer diameter surface of 34) and the inner diameter surface of the outer ring member (21) by a carrier (40) rotatably supported around the rotation shaft (34). A spiral groove or a circumferential groove (52) that is rotatably supported and meshes with a spiral protrusion (51) provided on the inner diameter surface of the outer ring member (21) on the outer diameter surface of the planetary roller (49). A thrust retainer roller that is formed and supports a thrust load applied to the planetary roller (49) between opposed surfaces of the planetary roller (49) and a disk (41a) provided on the carrier (40). (53) The rotation of the rotating shaft (34) causes the planetary roller (49) to rotate and revolve by frictional contact with the rotating shaft (34), thereby relatively rotating the outer ring member (21) and the carrier (40) in the axial direction. In the electric linear actuator that is moved linearly,
A common annular raceway (57) is incorporated in each of the plurality of thrust cage rollers (53) between the opposing surfaces of the plurality of thrust cage rollers (53) and the disk (41a). Electric linear actuator.   The electric linear actuator according to claim 1, wherein the raceway (57) is formed by plastic working, and the raceway surface (62) facing the thrust cage roller (53) is heat-treated. A cylindrical outer ring member (21) is incorporated in the housing (20), and a rotary shaft (34) rotated by an electric motor (24) is provided on the axis of the outer ring member (21). A plurality of planetary rollers (49) incorporated between the outer diameter surface of 34) and the inner diameter surface of the outer ring member (21) by a carrier (40) rotatably supported around the rotation shaft (34). A spiral groove or a circumferential groove (52) that is rotatably supported and meshes with a spiral protrusion (51) provided on the inner diameter surface of the outer ring member (21) on the outer diameter surface of the planetary roller (49). A thrust retainer roller that is formed and supports a thrust load applied to the planetary roller (49) between opposed surfaces of the planetary roller (49) and a disk (41a) provided on the carrier (40). (53) The rotation of the rotating shaft (34) causes the planetary roller (49) to rotate and revolve by frictional contact with the rotating shaft (34), thereby relatively rotating the outer ring member (21) and the carrier (40) in the axial direction. In the electric linear actuator that is moved linearly,
An electric linear motion characterized in that the inner surface of the disk (41a) facing the thrust cage roller (53) is a raceway surface (68) common to the plurality of thrust cage rollers (53). Actuator.   The electric linear actuator according to claim 3, wherein the disk (41a) is formed by plastic working and the raceway surface (68) is heat-treated. The brake pad (14) is linearly driven by the electric linear actuator (A), and the disc rotor (10) is pressed by the brake pad (14) to apply a braking force to the disc rotor (10). In the electric brake device
5. The electric brake device according to claim 1, wherein the electric linear actuator (A) comprises the electric linear actuator according to claim 1.

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