JP2008312437A - Electric direct acting actuator and electric braking device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric direct acting actuator having a short axial length. <P>SOLUTION: Between the outer diameter surface of a rotating shaft 14 driven through an electric motor 12 and the inner diameter surface of an outer ring member 13 secured to the outer diameter side of the rotating shaft 14, a plurality of planetary rollers 15 rotating around the rotating shaft 14 while revolving as the rotating shaft 14 rotates are interposed. A spiral groove 24 is formed in the outer diameter surface of each planetary roller 15, a spiral protrusion 23 engaging with the spiral groove 24 is provided on the inner diameter surface of the outer ring member 13, and rotation of the rotating shaft 14 is converted into axial movement of the planetary roller 15. In such an electric direct acting actuator, the stator 19 of the electric motor 12 is arranged to surround the outer circumference of the outer ring member 13, the cylindrical rotor 18 of the electric motor 12 is arranged oppositely to the radial direction of the stator 19, and a portion 22 for coupling the rotor 18 and the rotating shaft 14 is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric linear actuator that converts rotation of a rotary shaft driven by an electric motor into axial movement of a planetary roller, and an electric brake device using the electric linear actuator.

  As a vehicle brake device, a hydraulic brake device that drives a brake pad with a hydraulic cylinder and presses a brake disc has been adopted. However, in recent years, with the introduction of brake control such as ABS (anti-lock brake system), these brake devices are used. An electric brake device that can perform control without a hydraulic circuit has attracted attention. An electric brake device incorporates an electric linear actuator that converts rotation of a rotating shaft driven by an electric motor into axial movement of a planetary roller in a caliper body. When activated, braking force is generated by pressing the brake disc with the brake pads.

  As an electric linear actuator used in such an electric brake device, as shown in FIG. 16, the outer diameter surface of the rotating shaft 71 of the electric motor 70 and the outer ring member fixed to the outer diameter side of the rotating shaft 71. A plurality of planetary rollers 73 that revolve while rotating around the rotation shaft 71 as the rotation shaft 71 rotates are interposed between the inner diameter surfaces of 72 and the outer surface of each of these planetary rollers 73 in a spiral groove. 74 is formed on the outer diameter surface of the rotation shaft 71 to engage with the spiral groove 74, and the rotation of the rotation shaft 71 is caused by the planetary roller 73 by the engagement of the spiral groove 74 and the spiral protrusion 75. There is known one that converts the movement into an axial movement (Patent Document 1).

The electric motor 70 of the electric linear actuator includes a disk-like rotor 76 coupled to a rotating shaft 71 and a stator 77 facing the rotor 76 in the axial direction. The rotor 76 and the stator 77 is arranged in the outer ring member 72 side by side with the planetary roller 73 in the axial direction.
JP 2006-194356 A

  However, this electric linear actuator is long in the axial direction because the stator 77 and the planetary roller 73 are arranged side by side in the axial direction. For this reason, when this electric linear actuator is incorporated in an electric brake device, there is a problem that the axial length of the electric brake device becomes long and the installation space for components (for example, suspension) around the electric brake device becomes narrow.

  The problem to be solved by the present invention is to provide an electric linear actuator having a short axial length.

  In order to solve the above-mentioned problem, the stator of the electric motor is arranged so as to surround the outer periphery of the outer ring member, the cylindrical rotor of the electric motor is arranged so as to face the stator in the radial direction, and the rotor and the rotation shaft are arranged. A coupling portion for coupling was provided. If it does in this way, since the stator of an electric motor is arrange | positioned on the outer periphery of an outer ring member, axial direction length is shorter than what arranged the stator and the planetary roller side by side in the axial direction.

  In this configuration, the rotor may be disposed on the inner diameter side of the stator, but is preferably disposed on the outer diameter side of the stator. In this case, compared to the case where the rotor is disposed on the inner diameter side of the stator, the diameter of the surface of the rotor facing the stator is increased, so that the torque acting on the rotor can be increased.

  The coupling portion can be fixed to the rotating shaft by shrink fitting. Further, as a brake device incorporating the actuator, a brake device is provided in which a brake pad is driven by the actuator to press a brake disc.

  In the electric linear actuator according to the present invention, the stator of the electric motor is arranged so as to surround the outer periphery of the outer ring member. Therefore, the electric linear actuator is longer than the electric linear actuator in which the stator and the planetary roller are arranged in the axial direction. Is short.

  Moreover, since the electric linear actuator of this invention has arrange | positioned the stator of an electric motor in the outer periphery of an outer ring member, a bigger torque can be obtained rather than the electric linear actuator which arrange | positioned the stator in the outer ring member.

  In addition, the electric linear actuator having the rotor arranged on the outer diameter side of the stator has a larger diameter on the surface of the rotor facing the stator than the electric linear actuator arranged on the inner diameter side of the stator. It is possible to increase the torque to be applied.

  In addition, since the electric brake device in which the brake pad is driven by the electric linear actuator to press the brake disc has a short axial length, when the electric brake device is incorporated in a vehicle, There is a high degree of freedom in the layout of parts around the brake device.

  FIG. 1 shows an electric brake device for a vehicle. The electric brake device includes a caliper body 1, an electric linear actuator 2 according to the first embodiment of the present invention, brake pads 3 and 4, and a brake disk 5.

  The caliper body 1 includes opposed portions 6 and 7 that face each other with a brake disc 5 that rotates integrally with a wheel interposed therebetween, and a bridge portion 8 that couples the opposed portions 6 and 7 together. In the caliper body 1, the electric linear actuator 2 for moving the brake pad 3 is inserted into the insertion hole 10 provided in the facing surface 9 of the facing portion 6 with respect to the brake disc 5. A brake pad 4 is provided on the surface 11 facing the disk 5. The caliper body 1 is slidably supported by a slide pin (not shown) in a direction in which the brake pad 4 is brought into contact with and separated from the brake disk 5.

  As shown in FIG. 2, the electric linear actuator 2 includes an electric motor 12, an outer ring member 13, a rotating shaft 14, a planetary roller 15, a planetary carrier 16, and a brake pad moving member 17.

  The electric motor 12 includes a rotor 18 and a stator 19 that applies a rotational force to the rotor 18. As shown in FIG. 3, the stator 19 includes an annular stator core 20 disposed so as to surround the outer periphery of the outer ring member 13, and a plurality of electromagnetic coils 21 disposed at regular intervals in the circumferential direction. Each electromagnetic coil 21 is wound around a protrusion 20 a formed on the inner periphery of the stator core 20. The rotor 18 is formed in a cylindrical shape and is disposed between the stator 19 and the outer ring member 13. As a result, the rotor 18 is disposed on the inner diameter side of the stator 19 so as to face the stator 19 in the radial direction. It is in the state. A plurality of permanent magnets 18 a are attached to the outer diameter surface of the rotor 18 side by side in the circumferential direction.

  As shown in FIG. 2, the rotor 18 is coupled to a rotating shaft 14 that is coaxially inserted into the outer ring member 13 via a disk-shaped coupling portion 22 that is provided integrally with the rotor 18. Here, the coupling portion 22 may be fixed to the rotating shaft 14 using a fixing member such as a bolt or a key. However, if the fixing portion 22 is fixed by shrinkage fitting, the number of parts is reduced, and the manufacturing cost can be suppressed.

  A plurality of planetary rollers 15 are provided between the outer diameter surface of the rotating shaft 14 and the inner diameter surface of the outer ring member 13 fixed to the outer diameter side of the rotating shaft 14 at a constant interval in the circumferential direction. . The outer diameter surface of the planetary roller 15 is in contact with the outer diameter surface of the rotating shaft 14, and the rotation of the rotating shaft 14 is transmitted to the planetary roller 15 by friction between the contact surfaces. In addition, on the inner diameter surface of the outer ring member 13, a spiral projection 23 is formed by fitting a strip member into the spiral groove, and the spiral projection 23 is a spiral formed on the outer diameter surface of the planetary roller 15. The groove 24 is engaged. The spiral ridge 23 and the spiral groove 24 have different lead angles, and when the planetary roller 15 rotates, the spiral groove 24 of the planetary roller 15 is guided by the spiral ridge 23, and the planetary roller 15 moves in the axial direction. It is like that.

  The planetary roller 15 is supported so as to be rotatable about a support shaft 25, and the support shaft 25 is fixed to a planet carrier 16 that faces the planetary roller 15 in the axial direction. The planetary carrier 16 is supported on the rotary shaft 14 via a slide bearing 26, and can rotate with respect to the rotary shaft 14 and move in the axial direction by sliding of the slide bearing 26. A thrust ball bearing 27 is provided between the planetary carrier 16 and the planetary roller 15 to block the rotational movement of the planetary roller 15 about the support shaft 25 from being transmitted to the planetary carrier 16.

  The brake pad moving member 17 is inserted into the outer ring member 13 so as to be slidable in the axial direction, and is disposed opposite to the planet carrier 16 in the axial direction. A thrust ball bearing 28 is provided between the planet carrier 16 and the brake pad moving member 17 to block the rotational movement of the planet carrier 16 around the rotation shaft 14 from being transmitted to the brake pad moving member 17. The brake pad 3 is disposed in contact with the axial end surface 29 of the brake pad moving member 17.

  As shown in FIG. 3, between the adjacent planetary rollers 15, a fan-shaped lubricant application member 30 that is in sliding contact with the outer diameter surface of each planetary roller 15 is provided and enclosed in the outer ring member 13. The lubricant is applied to the outer diameter surface of the planetary roller 15 by the lubricant application member 30. Further, as shown in FIGS. 4A and 4B, a groove 32 is formed in the contact surface 31 of the lubricant application member 30 with respect to the planetary roller 15 so that the lubricant is accumulated in the groove 32. It has become. The lubricant application member 30 is supported by a case 33 shown in FIG.

  As shown in FIG. 5, the case 33 includes a partial cylindrical portion 34 that supports the outer diameter surface of the lubricant application member 30, and a bottom portion 36 that supports the axial end surface 35 of each lubricant application member 30. At the center of the bottom portion 36, a hole 37 is formed through which the rotary shaft 14 is rotatably passed. In addition, the support shaft 25 is fitted in a hole 38 formed in the bottom portion 36 of the case 33, and is fixed in the axial direction by a retaining ring 39 attached to the support shaft 25 as shown in FIG. . Therefore, when the planetary roller 15 moves in the axial direction, the case 33 moves along with the planetary roller 15 in the axial direction, and the lubricant application member 30 moves along with the case 33 in the axial direction.

  The electric brake device configured as described above operates as follows.

  When the electric motor 12 is operated, the rotating shaft 14 rotates, and the planetary roller 15 revolves around the rotating shaft 14 while rotating. At this time, the planetary roller 15 is moved in the axial direction by the engagement of the spiral ridge 23 and the spiral groove 24, and the axial movement of the planetary roller 15 is caused by the thrust ball bearing 27, the planet carrier 16, the thrust ball bearing 28, The brake pad 5 is transmitted to the brake pad 3 through the brake pad moving member 17 in order, and the brake disc 5 is pressed by the brake pad 3. Further, the caliper body 1 slides due to the reaction force acting on the brake pad 3, and the brake disc 5 is pressed by the brake pad 4. In this way, this electric brake device drives the brake pad 3 with the electric linear actuator 2 and presses the brake disc 5 with the brake pads 3 and 4.

  Since the electric linear actuator 2 is arranged so that the stator 19 surrounds the outer periphery of the outer ring member 13, the axial length is longer than the electric linear actuator in which the stator and the planetary roller are arranged side by side in the axial direction. Is short. For this reason, the electric brake device has a short axial length, and has a high degree of freedom in layout of components (for example, suspensions) around the electric brake device when incorporated in a vehicle.

  Further, since the electric linear actuator 2 is arranged so that the stator 19 of the electric motor 12 surrounds the outer periphery of the outer ring member 13, the stator 19 is more effective than the electric linear actuator in which the stator is arranged in the outer ring member 13. And a large torque can be applied to the rotor 18.

  In the electric linear actuator 2, the coaxially arranged rotor 18 and the rotary shaft 14 are coupled to each other. Therefore, the rotor shaft coupled to the rotor is arranged in parallel with the rotary shaft 14, and the rotor shaft rotates. Compared with the electric linear actuator that transmits the motor to the rotary shaft 14 via the intermediate gear, there is no rotor shaft and intermediate gear, and the cost is low.

  6 and 7 show an electric brake device incorporating the electric linear actuator 40 of the second embodiment of the present invention. The electric linear actuator 40 is configured by forming the planet carrier 41 by integrally forming the planet carrier 16 and the lubricant application member 30 of the first embodiment. Hereinafter, members corresponding to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  A plurality of planetary rollers 42 are provided between the inner diameter surface of the outer ring member 13 and the outer diameter surface of the rotary shaft 14 at a constant interval in the circumferential direction. A spiral groove 43 similar to the spiral groove 24 of the first embodiment is formed on the outer diameter surface of the planetary roller 42.

  As shown in FIG. 6, the planetary carrier 41 is provided so as to face the planetary roller 42 in the axial direction, and is supported on the rotary shaft 14 via the sliding bearing 26. A columnar protrusion 43 formed on the planet carrier 41 is fitted into a thrust ball bearing 27 provided between the planet roller 42 and the planet carrier 41.

  As shown in FIG. 7, the planetary carrier 41 is integrally provided with a fan-shaped lubricant application member 44 that is in sliding contact with the outer diameter surface of each adjacent planetary roller 42. As shown in FIG. 6, the lubricant application member 44 is provided with a bottom plate 47 that is opposed to the planetary roller 42 in the axial direction, and the planetary roller 42 is sandwiched between the bottom plate 47 and the planetary carrier 41. The bottom plate 47 is fixed to the lubricant application member 44 in the axial direction by a retaining ring 48. Therefore, when the planetary roller 42 moves in the axial direction, the planet carrier 41 also moves integrally in the axial direction. Further, as shown in FIG. 7, the lubricant application member 44 is provided with a groove 46 similar to the groove 32 of the first embodiment on the contact surface 45 with respect to the planetary roller 42.

  In this electric brake device, as in the first embodiment, when the electric motor 12 is operated, the planetary roller 42 is moved in the axial direction by the engagement of the spiral ridge 23 and the spiral groove 43, and the planetary roller 42 is axially moved. The movement is transmitted to the brake pad 3 through the planet carrier 41, and the brake disk 5 is pressed. Further, the revolving motion of the planetary roller 42 around the rotation shaft 14 is transmitted to the planetary carrier 41 via the lubricant application member 44. As a result, the planetary roller 42 and the planetary carrier 41 revolve integrally.

  Since the electric linear actuator 40 is arranged so that the stator 19 surrounds the outer periphery of the outer ring member 13, the axial length is short. For this reason, this electric brake device has a short axial length and has a high degree of freedom in layout of components around the electric brake device when incorporated in a vehicle. In addition, since the electric linear actuator 40 is arranged so that the stator 19 surrounds the outer periphery of the outer ring member 13, the torque acting on the rotor 18 is large.

  In addition, the electric linear actuator 40 does not have the support shaft 25 and is lower in manufacturing cost than the electric linear actuator 2 of the first embodiment.

  8 and 9 show an electric brake device incorporating an electric linear actuator 49 according to a third embodiment of the present invention. The electric linear actuator 49 is obtained by replacing the fan-shaped lubricant application member 30 of the first embodiment with a lubricant application member 50. Hereinafter, members corresponding to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Roller-like lubricant application members 50 provided between adjacent planetary rollers 15 and 15 are in rolling contact with the outer diameter surfaces of the planetary rollers 15 and 15 on both sides of the roller-like lubricant application members 50, and the inner ring member 13 is thereby in contact with each other. Is applied to the outer diameter surfaces of the planetary rollers 15 and 15. A groove 51 is formed on the outer diameter surface of the lubricant application member 50, and the lubricant is accumulated in the groove 51. The lubricant application member 50 is supported by the case 33.

  In the electric linear actuator 49, since the lubricant application member 50 is in rolling contact with the outer diameter surface of the planetary roller 15, the lubricant application member 50 and the planetary roller 15 are different from the electric linear actuator of the first embodiment. Hard to wear.

  10 and 11 show an electric brake device incorporating an electric linear actuator 52 according to a fourth embodiment of the present invention. The electric linear actuator 52 is obtained by replacing the fan-shaped lubricant application member 44 of the second embodiment with a lubricant application member 54. Hereinafter, members corresponding to those of the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Roller-like lubricant application members 54 provided between adjacent planetary rollers 42 and 42 are in rolling contact with the outer diameter surfaces of the planetary rollers 42 and 42 on both sides of the roller-like lubricant application member 54. Is applied to the outer diameter surfaces of the planetary rollers 42, 42. A groove 57 is formed on the outer diameter surface of the lubricant application member 54, and the lubricant is accumulated in the groove 57. The lubricant application member 54 is rotatably supported by a support shaft 55 provided integrally with the planet carrier 53.

  The electric linear motion actuator 52 transmits the revolving motion of the planetary roller 42 around the rotation shaft 14 to the planetary carrier 53 through the lubricant application member 54 and the support shaft 55 in order, and as a result, the planetary roller 42 and the planetary roller 42. The carrier 53 revolves integrally. Here, since the lubricant application member 54 is in rolling contact with the planetary roller 42, the lubricant application member 54 is not easily worn even when a large force acts between the planetary roller 42 and the lubricant application member 54.

  In each of the above embodiments, the spiral ridge 23 that engages with the spiral groove 24 of the planetary roller 15 is provided on the inner diameter surface of the outer ring member 13, but the spiral ridge that engages with the spiral groove 24 of the planetary roller 15 is Instead of the inner diameter surface of the outer ring member 13, it may be provided on the outer diameter surface of the rotating shaft 14.

  In each of the above embodiments, the spiral groove 24 is provided on the outer diameter surface of the planetary roller. However, a circumferential groove is provided in place of the spiral groove 24, and the circumferential groove is connected to the spiral ridge 23 of the outer ring member 13. You may make it engage. Even in this case, when the planetary roller rotates, the circumferential groove is guided by the spiral protrusion 23, so that the planetary roller moves in the axial direction.

  In the electric linear actuator 52 of the fourth embodiment, when the circumferential groove 58 is provided instead of the spiral groove 24, the outer diameter surface of the lubricant application member 54, as shown in FIGS. A circumferential ridge 59 that fits into the circumferential groove 58 of the planetary roller 42 can be formed. In this way, the lubricant can be applied directly to the inner surface of the circumferential groove 58 on the outer diameter surface of the planetary roller 42.

  14 and 15 show an electric brake device incorporating an electric linear actuator 60 according to a fifth embodiment of the present invention. The electric linear actuator 60 is obtained by replacing the electric motor 12 of the first embodiment with an electric motor 61. Hereinafter, members corresponding to those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The electric motor 61 includes a rotor 62 and a stator 63 that applies a rotational force to the rotor 62. The stator 63 includes an annular stator core 64 disposed so as to surround the outer periphery of the outer ring member 13 and a plurality of electromagnetic coils 65 disposed at a constant interval in the circumferential direction. It is wound around a protrusion 64 a formed on the outer periphery of 64. The rotor 62 is formed in a cylindrical shape, and is disposed on the outer diameter side of the stator 63 so as to face the stator 63 in the radial direction. A plurality of permanent magnets 62 a are attached to the inner diameter surface of the rotor 62 side by side in the circumferential direction.

  Since the electric linear actuator 60 has the rotor 62 disposed on the outer diameter side of the stator 63, the electric linear actuator 60 of the first embodiment in which the rotor 18 is disposed on the inner diameter side of the stator 19 The opposing surface 66 of the rotor 62 with respect to the stator 63 is located radially outward, and the opposing surface 66 has a large diameter. Therefore, the torque acting on the rotor 62 is large. Moreover, the electric brake device incorporating the electric linear actuator 60 has a good brake response.

  The electric motor 12 of the second to fourth embodiments may be replaced with the electric motor 61 to constitute an electric linear actuator. Even in this case, the torque generated by the electric linear actuator can be increased as in the fifth embodiment.

1 is a longitudinal sectional view showing an electric brake device incorporating an electric linear actuator according to a first embodiment of the present invention. 1 is an enlarged cross-sectional view of the vicinity of the electric linear actuator of the electric brake device shown in FIG. Sectional view along line III-III in FIG. (A) is the expanded sectional view which looked at the lubricant application member of Drawing 3 from the front, (b) is the expanded sectional view along the IVb-IVb line of (a) The perspective view which shows the case of FIG. A longitudinal sectional view showing an electric linear actuator of a second embodiment Sectional drawing along the VII-VII line of FIG. A longitudinal sectional view showing an electric linear actuator of a third embodiment Sectional view along line IX-IX in FIG. A longitudinal sectional view showing an electric linear actuator of a fourth embodiment Sectional view along line XI-XI in FIG. FIG. 10 is an enlarged cross-sectional view showing a modification of the electric linear actuator shown in FIG. Sectional view along line XIII-XIII in FIG. A longitudinal sectional view showing an electric linear actuator of a fifth embodiment Sectional view along line XV-XV in FIG. Expanded sectional view showing a conventional electric linear actuator

Explanation of symbols

3, 4 Brake pad 5 Brake disc 12 Electric motor 13 Outer ring member 14 Rotating shaft 15 Planetary roller 18 Rotor 19 Stator 22 Coupling portion 23 Spiral ridge 24 Spiral groove

Claims (5)

  Between the outer diameter surface of the rotating shaft (14) driven by the electric motor (12) and the inner diameter surface of the outer ring member (13) fixed to the outer diameter side of the rotating shaft (14), the rotating shaft ( A plurality of planetary rollers (15) that revolve while rotating around the rotation shaft (14) with the rotation of 14) are interposed, and each of these planetary rollers (15) and the outer ring member (13) or the rotation shaft (14) is provided with axial movement means (23, 24) for moving each planetary roller (15) in the axial direction along with its rotation and revolution, and the rotation of the rotary shaft (14) is controlled by the planetary roller. (15) In the electric linear actuator which is converted into the axial movement of (15), the stator (19) of the electric motor (12) is disposed so as to surround the outer periphery of the outer ring member (13), and the stator ( 19) and the electric power Cylindrical rotor (18) arranged, electric linear motion actuator which is characterized in that a coupling portion (22) for coupling the rotor (18) and said rotary shaft (14) of the motor (12).   The electric linear actuator according to claim 1, wherein the rotor (18) is disposed on an inner diameter side of the stator (19).   The electric linear actuator according to claim 1, wherein the rotor (18) is disposed on an outer diameter side of the stator (19).   The electric linear actuator according to any one of claims 1 to 3, wherein the coupling portion (22) is fixed to the rotating shaft (14) by shrink fitting.   5. The electric brake device according to claim 1, wherein the brake pad is driven by an electric linear actuator to press the brake disc. 5. The electric linear actuator according to claim 1. An electric brake device characterized by being a direct acting actuator.

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