JP5866852B2 - Actuator - Google Patents

Description

  The present invention relates to an actuator.

  2. Description of the Related Art Conventionally, a ball screw type direct acting actuator has been widely used as a power conversion device that obtains a large axial output from a relatively small input torque by using a ball screw that converts rotational motion into linear motion. When a relatively small input torque from a drive source such as an electric motor is input to a screw shaft (or nut) constituting a ball screw via a speed reduction mechanism, the screw shaft (or nut) is rotated in a desired direction. The rotational motion of the screw shaft (or nut) is converted into linear motion of the nut (or screw shaft) screwed with the screw shaft (or nut) via a plurality of balls. Then, the linear motion of the nut (or screw shaft) is taken out from the output shaft connected to the nut (or directly from the screw shaft).

In the type of actuator that converts the rotational motion of the screw shaft into the linear motion of the nut, the nut to which the output shaft is attached does not rotate around the screw shaft, as in the patent document 1, so Even if relative rotation between the housing member to be included is not prevented, rotation of the nut is prevented by preventing relative rotation between the nut and the output shaft.
In the thing of patent document 1, the rotation suppression member which consists of synthetic resins is used, and it is preventing that a nut rotates (idling) with respect to an output shaft. That is, the rotation restraining member includes a pair of engaging portions and an elastic connecting plate that connects both engaging portions, and is formed in a C shape. Then, the nut is rotated with respect to the output shaft by attaching the rotation restraining member while engaging the pair of engaging portions to the engaging portion formed by the recessed portion of the nut and the fitting portion of the output shaft. Prevents (idling).

Japanese Patent No. 3623380

  However, in most cases, not only the reaction force of the actuator but also a radial load is applied to the tip of the output shaft. If the output shaft is tilted due to radial load and the axis of the nut and screw shaft is misaligned, the efficiency of the ball screw may be reduced and functional loss may occur. Since the member cannot support the entire circumference of the nut, it has been difficult to sufficiently suppress the deviation of the axis between the nut and the screw shaft.

Further, if the inner peripheral surface of the connecting plate of the rotation restraining member is in close contact with the outer peripheral surface of the output shaft, when the pair of engaging portions are engaged with the locking portions, the rotation restraining member and the output are output. Since there is no gap between the shafts and between the rotation restraining member and the nut, the rotation restraining member cannot be attached. As a result, there is a risk that play in the rotational direction will occur between the output shaft and the nut. there were.
Accordingly, it is an object of the present invention to solve the above-described problems of the prior art and to provide a highly reliable actuator.

  In order to solve the above problems, the present invention has the following configuration. That is, the actuator according to the present invention is an actuator that converts a rotational motion into a linear motion, and is arranged coaxially in a substantially cylindrical or substantially rectangular tube-shaped housing member and an inner space of the housing member, and receives rotational force. A screw shaft, a nut engaged with the screw shaft so as to linearly move along the screw shaft as the screw shaft is rotated by the rotational force, and a straight line with the nut connected to the nut. An output shaft that moves to output an axial force, and a plurality of output shaft support members that are interposed between an outer peripheral surface of the output shaft and an inner peripheral surface of the housing member, and support the output shaft on the housing member And the following five conditions A, B, C, D, and E are satisfied.

Condition A: A hole extending in the axial direction and accommodating the screw shaft is formed at one axial end portion of the output shaft, and a female screw is provided on an inner peripheral surface of the hole, and an outer periphery of the nut The nut and the output shaft are connected by screwing a male screw and a female screw provided on the surface.
Condition B: A space is formed that includes a recess formed in a portion of the outer peripheral surface of the nut where the male screw is provided, and a through hole that continues to the recess and penetrates the output shaft in the radial direction. ing.
Condition C: A circumferential groove is formed on the entire circumference of the outer circumferential surface of the output shaft at the same position as the through hole in the axial direction.

Condition D: The first output shaft support member of the plurality of output shaft support members is a substantially annular member having a substantially C-shaped cross section having a slit extending in the axial direction. The second output shaft support member is a substantially annular member fitted into the circumferential groove so as to be in sliding contact with the peripheral surface, and the inner peripheral surface thereof is the outer peripheral surface of the output shaft. The housing member is attached in the vicinity of the axial end portion of the inner peripheral surface of the housing member so as to be in sliding contact.
Condition E: An engaging portion having substantially the same shape as the space protrudes radially inward from the inner peripheral surface of the first output shaft support member, and is fitted in the space.
In such an actuator according to the present invention, it is preferable that the first output shaft support member is made of an elastic material.

  The actuator according to the present invention is an actuator that converts a rotational motion into a linear motion, and is arranged coaxially in a substantially cylindrical or substantially rectangular tube-shaped housing member and an inner space of the housing member, and receives rotational force. A screw shaft, a nut engaged with the screw shaft so as to linearly move along the screw shaft as the screw shaft is rotated by the rotational force, and a straight line with the nut connected to the nut. An output shaft that moves to output an axial force, and a plurality of output shaft support members that are interposed between an outer peripheral surface of the output shaft and an inner peripheral surface of the housing member, and support the output shaft on the housing member And the following five conditions F, G, H, I, and J are satisfied.

Condition F: A hole extending in the axial direction and accommodating the screw shaft is formed at one axial end portion of the output shaft, and a female screw is provided on the inner peripheral surface of the hole, and the outer periphery of the nut The nut and the output shaft are connected by screwing a male screw and a female screw provided on the surface.
Condition G: A space formed by a recess formed in a portion of the outer peripheral surface of the nut where the male screw is provided, and a through hole that continues to the recess and penetrates the output shaft in the radial direction is an axis. A plurality are formed at the same position in the direction.
Condition H: A circumferential groove is formed on the entire circumference of the outer peripheral surface of the output shaft at the same position as the through hole in the axial direction.

Condition I: Among the plurality of output shaft support members, the first output shaft support member is formed by arranging a plurality of cross-section arc-shaped members so as to form a substantially annular shape, and the outer peripheral surface thereof is in sliding contact with the inner peripheral surface of the housing member. The second output shaft support member is a substantially annular member, and the inner peripheral surface is slidably contacted with the outer peripheral surface of the output shaft. It is attached in the vicinity of the axial end of the inner peripheral surface of the housing member.
Condition J: An engaging portion having substantially the same shape as the space protrudes radially inward from the inner circumferential surface of each cross-section arc-shaped member constituting the first output shaft support member, and fits in the space Has been.
Furthermore, in these actuators according to the present invention, when a corner portion is formed on the inner peripheral surface of the housing member, a portion of the outer peripheral surface of the first output shaft support member that faces the corner portion and It is preferable to form a relief portion comprising a recess in the vicinity thereof.

  In the actuator according to the present invention, the first output shaft support member that supports the output shaft on the housing member and prevents the nut from rotating relative to the output shaft (idling) covers the entire circumference of the output shaft. Because it is attached to the output shaft, it is highly reliable.

It is sectional drawing which shows the structure of one Embodiment of the actuator which concerns on this invention. It is a side view which shows the output shaft unit of the actuator of FIG. It is AA sectional drawing of the output shaft unit of FIG. It is a perspective view of a 1st output shaft support member. It is sectional drawing of the actuator of FIG. It is a figure which shows the modification of a 1st output shaft support member. It is a figure which shows another modification of a 1st output shaft support member. It is a perspective view which shows another modification of a 1st output shaft support member.

Embodiments of an actuator according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a structure of an embodiment of an actuator according to the present invention (a cross-sectional view cut along a plane along the axial direction), and FIG. 2 is a side view showing an output shaft unit of the actuator. FIG. 3 is a cross-sectional view of the output shaft unit of FIG.
The actuator of this embodiment uses a ball screw that converts rotational motion into linear motion, thereby converting a rotational force input from a drive source such as an electric motor into an axial force (axial force) and outputting the ball. It is a screw type direct acting actuator.

  The actuator of this embodiment includes a ball screw 10 that converts rotational motion into linear motion, and a rotational force transmission unit 20 that receives rotational force from a drive source such as an electric motor (not shown) and transmits the rotational force to the screw shaft 1 of the ball screw 10. An output shaft 30 connected to the nut 3 of the ball screw 10 and outputting the axial force converted from the rotational force by the ball screw 10, and a substantially cylindrical shape (substantially rectangular tube shape) containing the ball screw 10 and the output shaft 30. The housing member 40 may be provided. In addition, what consists of the ball screw 10 and the output shaft 30 is called an output shaft unit.

  The ball screw 10 includes a screw shaft 1 having a helical screw groove 1a on the outer peripheral surface, a nut 3 having a helical screw groove 3a facing the screw groove 1a of the screw shaft 1 on the inner peripheral surface, and both screws. A plurality of balls (not shown) that are slidably loaded in a spiral ball rolling path formed by the grooves 1a and 3a, and the balls are circulated back from the end point of the ball rolling path to the starting point. A ball circulation path 5.

In other words, the ball moves around the screw shaft 1 while moving in the ball rolling path to reach the end point of the ball rolling path, where it is scooped up from the ball rolling path and passes through the ball circulation path 5. Enter one end. The ball that has entered the ball circulation path 5 passes through the ball circulation path 5 and reaches the other end of the ball circulation path 5 and is returned to the starting point of the ball rolling path.
In addition, the material of the screw shaft 1, the nut 3, and the ball is not particularly limited, and general materials can be used, and examples thereof include metals such as steel and ceramics. Further, the cross-sectional shape of the thread grooves 1a, 3a may be an arc shape or a gothic arc shape.

  When such a ball screw 10 relatively rotates the nut 3 and the screw shaft 1 screwed to the screw shaft 1 through the ball, the screw shaft 1 and the nut 3 are moved through the rolling of the ball. And move relative to each other in the axial direction. An endless ball path is formed by the ball rolling path and the ball circulation path 5 so that the ball rolling in the ball rolling path circulates infinitely in the endless ball path. Therefore, the screw shaft 1 and the nut 3 can continuously move relative to each other.

  The ball screw 10 and the output shaft 30 connected to the nut 3 of the ball screw 10 are contained in the internal space of the housing member 40, and the screw shaft 1 and the output shaft 30 of the ball screw 10 are the housing. It is arranged coaxially with the member 40. A substantially cylindrical bottomed hole 30a extending in the axial direction is formed at one axial end portion (left end portion in FIG. 1) of the output shaft 30. When the nut 3 moves linearly in the axial direction, the screw shaft A part of 1 can be accommodated in the bottomed hole 30a. The screw shaft 1 cannot move in the axial direction. Moreover, you may provide the hole which penetrates the output shaft 30 to an axial direction instead of the bottomed hole 30a.

  An internal thread is provided on the inner peripheral surface near the opening of the bottomed hole 30a. The end of the nut 3 on the side facing the output shaft 30 is a small-diameter cylindrical portion 3b having a smaller diameter than the other portions, and a male screw is provided on the outer peripheral surface of the small-diameter cylindrical portion 3b. It has been. And the small diameter cylindrical part 3b is distribute | arranged in the bottomed hole 30a, and the nut 3 and the output shaft 30 are connected by the said male screw and the said female screw being screwed together.

  Since the nut 3 and the output shaft 30 are connected by screwing, the screw portion 31 transmits the axial force from the nut 3 to the output shaft 30. That is, the screwing portion 31 corresponds to an axial force transmission means from the nut 3 to the output shaft 30. However, since the nut 3 and the output shaft 30 are connected by screwing, the relative rotation (idling) between the nut 3 and the output shaft 30 may occur, and thus a relative rotation preventing means for suppressing this is necessary. It is. In addition, the connection method of the nut 3 and the output shaft 30 is not limited to screwing, A conventional fixing method can be employ | adopted without a problem. When a fixing method other than screwing is adopted, it may be necessary to separately provide other axial force transmission means.

  Below, the relative rotation prevention means of the nut 3 and the output shaft 30 is demonstrated. On the outer peripheral surface of the small-diameter cylindrical portion 3b of the nut 3 (that is, the portion where the male screw is provided), one rectangular parallelepiped concave portion 55 is formed. Further, the output shaft 30 is formed with a through-hole 57 having a rectangular cross section that is continuous with the recess 55 and penetrates the output shaft 30 in the radial direction. The continuous recess 55 and the through-hole 57 prevent relative rotation. A space 59 into which the element 51 is fitted is formed.

  Since the relative rotation preventing element 51 is a substantially rectangular parallelepiped member having substantially the same shape as the space 59, the relative rotation preventing element 51 can be fitted into the space 59. Although the relative rotation prevention element 51 will be described in detail later, the relative rotation prevention element 51 is fitted in the space 59 and the nut 3 and the output shaft 30 are engaged. Relative rotation (idling) is suppressed.

  On the other hand, a plurality (two in this embodiment) of output shaft support members that support the output shaft 30 on the housing member 40 are spaced apart in the axial direction from the outer peripheral surface of the output shaft 30 and the inner periphery of the housing member 40. It is interposed between the surfaces. These output shaft support members are substantially annular members substantially along the outer peripheral surface of the output shaft 30 and the inner peripheral surface of the housing member 40, and the first output shaft support member 61 is disposed at the same position in the axial direction as the space 59. (See FIGS. 1 and 2).

More specifically, the first output shaft support member 61 is a substantially annular member having a substantially C-shaped cross section having a slit extending in the axial direction (cross sectional shape cut by a plane perpendicular to the axial direction), and An engaging portion 61a having substantially the same shape as the space 59 protrudes radially inward from the inner peripheral surface (see FIG. 4). A circumferential groove 53 is formed on the entire circumference of the output shaft 30 at the same position as the through hole 57 on the outer circumferential surface of the output shaft 30, and the first output shaft support member 61 has an outer circumferential surface within the housing member 40. The output shaft 30 is fitted into the circumferential groove 53 so as to be in sliding contact with the circumferential surface.
At this time, the first output shaft support member 61 is attached so that the engaging portion 61 a is fitted in the space 59. That is, the engaging portion 61a of the first output shaft support member 61 corresponds to the aforementioned relative rotation prevention element 51, and the first output shaft support member 61 is a member that also serves as a relative rotation prevention means.

Next, the second output shaft support member 63 is arranged at the axial end portion (right end portion in FIG. 1) of the housing member 40 with a space in the axial direction from the first output shaft support member 61. The second output shaft support member 63 is a substantially annular member, and is attached to the axial end of the inner peripheral surface of the housing member 40 so that the inner peripheral surface thereof is in sliding contact with the outer peripheral surface of the output shaft 30.
The first output shaft support member 61 is fixed to the outer peripheral surface of the output shaft 30 and is loosely fitted to the inner peripheral surface of the housing member 40. On the other hand, the second output shaft support member 63 is fixed to the inner peripheral surface of the housing member 40 and is loosely fitted to the outer peripheral surface of the output shaft 30. Further, the first output shaft support member 61 and the second output shaft support member 63 are made of a material that has excellent sliding characteristics and is less susceptible to friction and wear, and friction is generated between the output shaft 30 and the housing member 40. It is hard to occur.

  The first output shaft support member 61 is preferably made of an elastic material. Then, without using a special tool, the operator can easily attach the first output shaft support member 61 to the output shaft 30 by manually expanding the slit. Examples of the elastic material include resins such as fluororesin (polytetrafluoroethylene), polyacetal, polyamide, polyester, and polyethylene. On the other hand, the second output shaft support member 63 is preferably made of graphite, soft metal, or sintered metal in addition to the same resin as the first output shaft support member 61.

  A gear constituting the rotational force transmitting portion 20 is attached to an end portion (left end portion in FIG. 1) opposite to the side facing the output shaft 30 of both ends of the screw shaft 1, and an electric motor or the like (not shown) Rotational force is received from the drive source and is transmitted to the screw shaft 1. For example, in the case of a shift actuator for an outboard motor, the rotational force input from the electric motor while decelerating via a spur gear or the like is transmitted to a screw shaft fitted to the gear by a spline or the like. It is like that.

  When the screw shaft 1 is rotated by the input rotational force, the nut 3 is linearly moved along the screw shaft 1 accordingly. The linear movement direction of the nut 3 is determined by the rotation direction of the screw shaft 1. When the nut 3 moves linearly, the axial force is transmitted to the output shaft 30 by the screwing portion 31, and the output shaft 30 moves linearly (forward or backward) together with the nut 3, so that the axial force is output from the output shaft 30. .

At this time, since the first output shaft support member 61 is attached to the outer peripheral surface of the output shaft 30, the first output shaft support member 61 moves in the axial direction together with the output shaft 30 while sliding with the inner peripheral surface of the housing member 40. Further, since the second output shaft support member 63 is fixed to the inner peripheral surface of the housing member 40, the second output shaft support member 63 does not move in the axial direction, and slides with the outer peripheral surface of the output shaft 30 as the output shaft 30 moves. To do.
In the actuator of this embodiment, the nut 3 and the output shaft 30 are coupled by screwing, and the relative rotation (idling) between the nut 3 and the output shaft 30 is performed by the engaging portion 61a of the first output shaft support member 61. Therefore, downsizing is possible. In addition, since the first output shaft support member 61 and the second output shaft support member 63 can be arranged with a large axial distance, the stroke amount is small despite the small size of the actuator of this embodiment. large.

  Further, since the engaging portion 61a of the first output shaft support member 61 that supports the output shaft 30 to the housing member 40 is fitted in the space 59, and the nut 3 and the output shaft 30 are engaged, the nut 3 And the relative rotation (idling) with the output shaft 30 are reliably prevented. Further, since the first output shaft support member 61 is attached so as to cover the entire circumference of the output shaft 30, the nut 3 and the screw shaft 1 are not affected even if a radial load is applied to the axial end of the output shaft 30. The deviation of the shaft center is sufficiently suppressed, and the efficiency reduction and functional loss of the ball screw 10 are hardly caused. Further, backlash in the rotational direction is unlikely to occur between the nut 3 and the output shaft 30. Therefore, the actuator of this embodiment has high reliability.

  Further, the first output shaft support member 61 is fitted in the circumferential groove 53 of the output shaft 30 with a tolerance setting that allows the inner peripheral surface of the housing member 40 to slide, that is, the outer peripheral surface of the output shaft 30 and the housing. Since the gap between the inner peripheral surface of the member 40 is smaller than the thickness of the first output shaft support member 61 (the thickness of the portion other than the engaging portion 61a), the first output shaft support member is used when the actuator is used. There is no possibility that 61 will come off the circumferential groove 53.

  Conventionally, keys and link pins incorporated as means for preventing relative rotation between the nut 3 and the output shaft 30 may fall off when the actuator is used. However, the actuator according to the present embodiment has no such a concern. . In addition, when assembling keys and link pins, complicated work such as press-fitting and caulking was necessary to prevent falling off, but the actuator of this embodiment can be used by an operator without using a tool. The first output shaft support member 61 can be attached.

Furthermore, since the engaging portion 61a, which is the relative rotation preventing element 51, is integrated with the first output shaft support member 61, the number of parts of the actuator can be reduced, and the relative rotation preventing element 51 can be used as the first output shaft support member. There is no need to consider the problem of the relative rotation preventing element 51 falling off from the space 59 that occurs when it is separate from 61.
Such an actuator can be particularly suitably used as a shift actuator (forward / reverse switching actuator) of an outboard motor. Moreover, it can be used suitably also for the damping device which reduces a vibration, and is suitable for the damping device for vehicles in a damping device. An actuator can be installed between the vehicle body and a grounding component such as a wheel to reduce vibrations generated in the vehicle body. Specifically, vibration of the vehicle body is detected, a control force having a phase opposite to that of the vibration is generated by an actuator, and the control force is applied to the vehicle body, thereby damping the vehicle body. For example, in vibration control of a railway vehicle, an actuator is installed between the vehicle body and the carriage, and a control force having a phase opposite to that of the vehicle body is generated by the actuator to reduce the vibration generated in the vehicle body.

  In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, in the actuator of this embodiment, in order to prevent interference between a return tube (ball circulation path 5 for circulating the ball from the end point of the ball rolling path to the start point) provided on the nut 3 and the housing member 40. It is preferable to provide the relief portion 71. That is, as shown in FIG. 5, it is preferable to provide a space capable of accommodating the return tube between the inner peripheral surface of the housing member 40 and the outer peripheral surface of the output shaft 30.

  Further, the corner portion formed at the boundary between the inner peripheral surface of the housing member 40 and the escape portion 71 comes into contact with the outer peripheral surface of the first output shaft support member 61, and the first output shaft support member 61 is damaged. In order to prevent this, the first output shaft support member 61 has a small diameter (that is, a thicker portion) as shown in FIG. It is preferable that the escape portion 72 made of a concave portion is formed.

  Further, when the ball circulation path 5 is formed using a piece instead of the return tube, it is not necessary to provide the escape portion 71 in the housing member 40. In such a case, the first output shaft support member 61 is provided. It is preferable that the entire outer peripheral surface of the housing is in contact with and supported by the housing member 40. Therefore, in such a case, as shown in FIG. 6, the escape portion 72 is not formed on the outer peripheral surface of the first output shaft support member 61 and a slit extending in a direction inclined with respect to the axial direction is formed. It is good to provide. If it does so, a load can be received in the perimeter of the outer peripheral surface of the 1st output-shaft support member 61. FIG. 6A is a view of the first output shaft support member 61 as viewed from one side in the axial direction, and FIG. 6B is a view as viewed from the side where the slit is formed. .

  Further, when the first output shaft support member 61 is manufactured by melt molding of a resin material, for example, a lightening portion 61b as shown in FIG. 7 is provided in the engagement portion 61a in order to prevent the occurrence of sink marks. preferable. 7A is a view of the first output shaft support member 61 as viewed from one side in the axial direction, and FIG. 7B is a view as viewed from the side where the engaging portion 61a is formed. is there. The thinned portion 61b also functions as a lubricant reservoir that holds a lubricant such as lubricating oil and grease.

  Furthermore, in the actuator of the present embodiment, the first output shaft support member 61 is a member having a substantially C-shaped cross section, but the first output shaft support member 61 is replaced with a plurality of cross-section arc-shaped members 62 (perpendicular to the axial direction). The shape of the first output shaft support member 61 including two cross-section arc-shaped members 62 is shown in FIG. That is, the first output shaft support member 61 may be configured by arranging a plurality of cross-section arc-shaped members 62 as a whole so as to form a substantially annular shape. And the engaging part 61a of the substantially same shape as the space 59 protrudes from the inner peripheral surface of each arcuate member 62 in the radial direction.

  In this case, a plurality of spaces 59 are formed at the same position in the axial direction in accordance with the number and phase of the engaging portions 61a, and each engaging portion 61a is fitted in the space 59 of the corresponding phase. . Further, in the case of the first output shaft support member 61 having a substantially C-shaped cross section, it is preferable that the first output shaft support member 61 is made of an elastic material in order to be attached to the output shaft 30 by expanding the slit. In the case of being constituted by a plurality of cross-section arc-shaped members 62, it is not necessary to be constituted by an elastic material, and it is also possible to be constituted by a highly rigid material. If it is made of a highly rigid material, it is possible to transmit axial force from the nut 3 to the output shaft 30 via the first output shaft support member 61. Even when the first output shaft support member 61 is composed of a plurality of cross-section arcuate members 62 as described above, the escape portion 71 and the escape portion 72 may be provided.

Further, the shape of the engaging portion 61a is not particularly limited, and it may be a rectangular parallelepiped shape, a cubic shape, a cylindrical shape, or a spherical shape, and the shape as shown in FIG. 4, that is, both ends in the long side direction of the rectangular parallelepiped are chamfered. It may be a cylindrical shape.
Furthermore, in the actuator of the present embodiment, the recess 55 is formed in a portion of the outer peripheral surface of the nut 3 where the male screw is provided, but if it is a portion covered by the inner peripheral surface of the output shaft 30. The recess 55 may be formed in a portion of the outer peripheral surface of the nut 3 where the male screw is not provided.

Furthermore, in the actuator according to the present embodiment, the outer peripheral surface of the nut 3 and the inner peripheral surface of the output shaft 30 are screwed and screwed, but on the contrary, the inner peripheral surface of the nut 3 and the output shaft 30 are A screw may be formed on the outer peripheral surface and screwed together. In this case, the screw on the inner peripheral surface of the nut 3 may be formed by providing a surface radially outward from the surface on which the thread groove 3a is formed.
Furthermore, in the actuator of the present embodiment, the screwing portion 31 is an axial force transmission means from the nut 3 to the output shaft 30, but the axial force transmission means is not limited to this. For example, an axial force may be transmitted by engaging an axial force transmission element such as a cotter with the nut 3 and the output shaft 30.

  Furthermore, as shown in FIG. 1, the actuator of the present embodiment may be provided with a seal member that seals the opening of the gap between the output shaft 30 and the housing member 40. Furthermore, a bellows-like member such as a bellows that covers the opening of the gap between the output shaft 30 and the housing member 40 and expands and contracts according to the advancement and retraction of the output shaft 30 may be provided. Furthermore, in the actuator of the present embodiment, a slide screw, a roller screw, or the like can be used instead of the ball screw 10.

DESCRIPTION OF SYMBOLS 1 Screw shaft 3 Nut 10 Ball screw 30 Output shaft 30a Bottomed hole 31 Screwing part 40 Housing member 51 Relative rotation prevention element 53 Circumferential groove 55 Recessed part 57 Through-hole 59 Space 61 First output shaft support member 61a Engaging part 62 Circular arc member 63 Second output shaft support member 72 Relief part

Claims (4)

In an actuator that converts rotational motion into linear motion,
A substantially cylindrical or substantially rectangular tubular housing member;
A screw shaft that is coaxially arranged in the internal space of the housing member and receives rotational force;
A nut engaged with the screw shaft so as to linearly move along the screw shaft as the screw shaft is rotated by the rotational force;
An output shaft connected to the nut and linearly moving with the nut to output an axial force;
A plurality of output shaft support members interposed between an outer peripheral surface of the output shaft and an inner peripheral surface of the housing member, and supporting the output shaft on the housing member;
And an actuator characterized by satisfying the following six conditions A, B, C, D, E , and K:
Condition A: A hole extending in the axial direction and accommodating the screw shaft is formed at one axial end portion of the output shaft, and a female screw is provided on an inner peripheral surface of the hole, and an outer periphery of the nut The nut and the output shaft are connected by screwing a male screw and a female screw provided on the surface.
Condition B: A space is formed that includes a recess formed in a portion of the outer peripheral surface of the nut where the male screw is provided, and a through hole that continues to the recess and penetrates the output shaft in the radial direction. ing.
Condition C: A circumferential groove is formed on the entire circumference of the outer circumferential surface of the output shaft at the same position as the through hole in the axial direction.
Condition D: The first output shaft support member of the plurality of output shaft support members is a substantially annular member having a substantially C-shaped cross section having a slit extending in the axial direction. The second output shaft support member is a substantially annular member fitted into the circumferential groove so as to be in sliding contact with the peripheral surface, and the inner peripheral surface thereof is the outer peripheral surface of the output shaft. The housing member is attached in the vicinity of the axial end portion of the inner peripheral surface of the housing member so as to be in sliding contact.
Condition E: An engaging portion having substantially the same shape as the space protrudes radially inward from the inner peripheral surface of the first output shaft support member, and is fitted in the space.
Condition K: A corner portion is formed on the inner peripheral surface of the housing member, and a relief portion including a recess is formed in a portion facing the corner portion and in the vicinity thereof on the outer peripheral surface of the first output shaft support member. Is formed.   The actuator according to claim 1, wherein the first output shaft support member is made of an elastic material. In an actuator that converts rotational motion into linear motion,
A substantially cylindrical or substantially rectangular tubular housing member;
A screw shaft that is coaxially arranged in the internal space of the housing member and receives rotational force;
A nut engaged with the screw shaft so as to linearly move along the screw shaft as the screw shaft is rotated by the rotational force;
An output shaft connected to the nut and linearly moving with the nut to output an axial force;
A plurality of output shaft support members interposed between an outer peripheral surface of the output shaft and an inner peripheral surface of the housing member, and supporting the output shaft on the housing member;
And an actuator characterized by satisfying the following five conditions F, G, H, I, and J:
Condition F: A hole extending in the axial direction and accommodating the screw shaft is formed at one axial end portion of the output shaft, and a female screw is provided on the inner peripheral surface of the hole, and the outer periphery of the nut The nut and the output shaft are connected by screwing a male screw and a female screw provided on the surface.
Condition G: A space formed by a recess formed in a portion of the outer peripheral surface of the nut where the male screw is provided, and a through hole that continues to the recess and penetrates the output shaft in the radial direction is an axis. A plurality are formed at the same position in the direction.
Condition H: A circumferential groove is formed on the entire circumference of the outer peripheral surface of the output shaft at the same position as the through hole in the axial direction.
Condition I: Among the plurality of output shaft support members, the first output shaft support member is formed by arranging a plurality of cross-section arc-shaped members so as to form a substantially annular shape, and the outer peripheral surface thereof is in sliding contact with the inner peripheral surface of the housing member. The second output shaft support member is a substantially annular member, and the inner peripheral surface is slidably contacted with the outer peripheral surface of the output shaft. It is attached in the vicinity of the axial end of the inner peripheral surface of the housing member.
Condition J: An engaging portion having substantially the same shape as the space protrudes radially inward from the inner circumferential surface of each cross-section arc-shaped member constituting the first output shaft support member, and fits in the space Has been. A corner portion is formed on the inner peripheral surface of the housing member, and a relief portion including a recess is formed in a portion facing the corner portion and a portion in the vicinity thereof on the outer peripheral surface of the first output shaft support member. The actuator according to claim 3 .

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