JP2018132136A - Actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an actuator capable of simplifying a constitution for oil supply, and a constitution for air bleeding in operation.SOLUTION: An actuator includes a housing, a ball screw shaft disposed in the housing and rotated and driven by a driving motor, a ball screw nut engaged with the ball screw shaft in a state of being restricted in rotation, and a hollow rod fixed to the ball screw nut. By rotating the driving motor properly in a forward or backward direction, the ball screw shaft is rotated in the same direction, thus the ball screw nut and the hollow rod are moved forward and backward in an axial direction of the ball screw shaft. The housing is provided with an oil supply hole, an oil supply cap is detachably attached to the oil supply hole, and an air bleeding portion is formed on the oil supply cap.SELECTED DRAWING: Figure 4

Description

  The present invention relates to, for example, a rod-type actuator, and more particularly to a device devised so that the configuration for refueling and the configuration for air bleeding during operation can be simplified.

For example, Patent Literature 1 discloses a conventional actuator.
First, an oil bath type electric cylinder described in Patent Document 1 includes an upright outer cylinder, a screw shaft installed in the upright inner cylinder and rotated and driven by a motor, and a nut screwed onto the screw shaft. And an upright inner cylinder fixed to the nut and installed so as to be able to protrude and retract with respect to the upright outer cylinder. A flow hole is formed below the upright inner cylinder, and a lubricant is sealed so as to flow through the lower side of the upright inner cylinder and the upright outer cylinder through the flow hole. This lubricant is injected through an injection hole provided in the upright outer cylinder.

  The upper side of the upright inner cylinder is an air chamber and communicates with the outside through an air communication hole. The atmospheric communication hole prevents a change in pressure in the air chamber when the upright inner cylinder moves. When not in use, the air communication hole is closed by a cap.

Utility Model Registration No. 2525912

The conventional configuration has the following problems.
In the case of the oil bath type electric cylinder described in Patent Document 1, an injection hole for supplying a lubricant is provided therein, and separately, the pressure change in the air chamber when the upright inner cylinder moves. There is a problem that the structure becomes complicated because the air communication hole is provided in order to prevent the upright inner cylinder from moving smoothly.

  The present invention has been made based on such points, and an object of the present invention is to provide an actuator capable of simplifying a configuration for refueling and a configuration for bleeding air during operation. is there.

In order to achieve the above object, an actuator according to claim 1 of the present invention comprises a housing, a ball screw shaft that is housed in the housing and is rotated and driven by a drive motor, and the rotation of the ball screw shaft is restricted. And a hollow rod fixed to the ball screw nut, and the ball screw shaft is rotated in the same direction by rotating the drive motor in a proper forward or reverse direction. Accordingly, in the actuator for moving the ball screw nut and the hollow rod back and forth in the axial direction of the ball screw shaft, the housing is provided with an oil supply hole and an oil supply cap is detachably attached to the oil supply hole. It is attached and the said oil supply cap is provided with the air bleeding part, It is characterized by the above-mentioned.
According to a second aspect of the present invention, in the actuator according to the first aspect of the present invention, the air bleed portion is a ventilation portion that communicates the inside and the outside of the oil supply cap.
According to a third aspect of the present invention, in the actuator according to the second aspect, the vent is always open.
According to a fourth aspect of the present invention, in the actuator according to the second aspect, the vent is opened when an internal pressure is applied.
An actuator according to claim 5 is the actuator according to any one of claims 1 to 4, characterized in that a concave portion is provided inside the air vent portion of the oil filler cap. is there.
According to a sixth aspect of the present invention, in the actuator according to the fifth aspect, a filter is detachably mounted in the recess.

As described above, according to the actuator according to the first aspect of the present invention, the housing, the ball screw shaft that is housed in the housing and is rotated and driven by the drive motor, and the rotation is regulated by the ball screw shaft. A ball screw nut screwed in a state and a hollow rod fixed to the ball screw nut, and rotating the drive motor in a proper forward or reverse direction to rotate the ball screw shaft in the same direction. In the actuator that rotates and thereby moves the ball screw nut and the hollow rod forward and backward in the axial direction of the ball screw shaft, the housing is provided with an oil supply hole, and an oil supply cap can be attached to and detached from the oil supply hole. The oiling cap is provided with an air vent, so the configuration and operation for refueling It is possible to simplify the configuration for the air vent.
Further, according to the actuator according to claim 2, in the actuator according to claim 1, since the air bleeding part is a ventilation part communicating with the inside and outside of the oiling cap, the structure for air bleeding is very simple.
Further, according to the actuator according to claim 3, in the actuator according to claim 2, since the ventilation portion is always open, air can be surely removed during operation.
Further, according to the actuator according to claim 4, in the actuator according to claim 2, since the ventilation portion is opened when an internal pressure is applied, it is securely closed except for air bleeding to prevent entry of foreign matter from the outside. Can be achieved.
Further, according to the actuator according to claim 5, in the actuator according to any one of claims 1 to 4, since the recess is provided inside the air bleeding part of the oil filler cap, the oil filler cap is deformed. It becomes easy to make it easy to attach and detach the oil supply hole.
Further, according to the actuator according to claim 6, in the actuator according to claim 5, since the filter is detachably mounted in the recess, the entry of foreign matter can be more reliably prevented. .

It is a figure which shows one embodiment of this invention, and is a perspective view of an actuator. It is a figure which shows one embodiment of this invention, and is II-II sectional drawing of FIG. It is a figure which shows one embodiment of this invention, and is an enlarged view of the III section of FIG. FIG. 4A is a perspective view of an oil supply cap, FIG. 4B is a sectional view taken along line IVb-IVb in FIG. 4A, and FIG. It is IVc-IVc sectional drawing of (a).

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
The actuator 1 according to this embodiment has a housing 3 as shown in FIGS. The housing 3 is installed on a substantially cylindrical frame 5, a front cap 7 covered on the front end side (left side in FIG. 2) of the frame 5, and the rear end side (right side in FIG. 2) of the frame 5. The rear bracket 9 and a motor case 11 installed on the rear end side (right side in FIG. 2) of the rear bracket 9 are configured.

  As shown in FIG. 2, a front cap mounting male screw portion 13 is formed on the outer peripheral surface of the front end side (left side in FIG. 2) of the frame 5, and the rear end side (right side in FIG. 2) of the frame 5 is formed. ) Is formed with a rear bracket mounting male screw portion 15.

A through hole 17 is formed in the front cap 7. The rear end side (right side in FIG. 2) of the through-hole 17 has an enlarged diameter, and a front cap attaching female thread portion 19 is formed here. When the front cap attaching female screw portion 19 and the front cap attaching male screw portion 13 of the frame 5 are screwed together, the front cap 7 is screwed and fixed to the frame 5.
The tip end side (left side in FIG. 2) of the through hole 17 is reduced in diameter, and a bearing installation recess 21 is formed here. A cylindrical slide bearing 23 is installed in the bearing installation recess 21.

  The rear bracket 9 is composed of a rear bracket body 25 and a jacket 27 that covers the outer peripheral side of the rear bracket body 25. The rear bracket body 25 is made of, for example, die casting, and the jacket 27 is made of, for example, resin.

  A recess 29 is formed on the front end side (left side in FIG. 2) of the rear bracket body 25. A rear bracket mounting female thread portion 31 is formed on the inner peripheral surface of the recess 29. The rear bracket 9 is attached to the frame 5 by screwing the rear bracket attaching male screw portion 15 of the frame 5 to the rear bracket attaching female screw portion 31.

As shown in FIGS. 2 and 3, a through hole 33 is formed in the rear bracket body 25. The front end side (left side in FIG. 2) of the through hole 33 communicates with the concave portion 29. Further, a bearing mounting recess 35 is formed on the tip side of the through hole 33 (left side in FIG. 2). Bearings 37 and 37 are installed in the bearing mounting recess 35. These bearings 37, 37 are respectively composed of an outer ring 39 abutting on the inner peripheral surface of the bearing mounting recess 35, an inner ring 41 installed inside the outer ring 39, and the inner ring 41 and the outer ring 39. The retainer 43 is disposed between the retainer 43 and a plurality of steel balls 45 that are held by the retainer 43 and rolled between the inner ring 41 and the outer ring 39.
A bearing retainer 47 is provided on the distal end side (left side in FIG. 2) of the through hole 33. Outer rings 39 and 39 of the bearings 37 and 37 are fixed between the bearing retainer 47 and the rear bracket body 25.

  An oil supply hole 49 is formed on the upper side of the rear bracket body 25 in FIG. A recess 51 is formed on the outer peripheral side of the through hole 33 in the rear bracket body 25, and the oil supply hole 49 and the inside of the frame 5 are communicated with each other through the recess 51.

  A through hole 53 slightly larger than the oil supply hole 49 is formed on the upper side of the jacket 27 in FIG. The oil supply hole 49 is exposed to the outside of the jacket 27 through the through hole 53.

  The motor case 11 includes a motor case main body 55 installed on the rear end side (right side in FIG. 2) of the rear bracket 9 and an end cover 57 that closes the rear end side of the motor case main body 55. . The motor case main body 55 is penetrated by a plurality of bolts (not shown), and these bolts are screwed into a female screw portion (not shown) formed at the rear end (right end in FIG. 2) of the rear bracket main body 25. Thus, the rear bracket body 25 is fixed. The end cover 57 is also penetrated by a plurality of bolts (not shown), and these bolts are screwed into a female screw portion (not shown) formed at the rear end (right end in FIG. 2) of the motor case body 55. As a result, the motor case main body 55 is fixed.

  A drive motor 59 is installed in the motor case 11. The drive motor 59 has a motor housing 61, and a stator 63 is installed inside the motor housing 61. An output shaft 65 is rotatably installed inside the stator 63, and a rotor 67 is fixed to the output shaft 65.

  An encoder 69 is installed on the rear end side (right side in FIG. 2) of the drive motor 59. The encoder 69 has an encoder wheel 71 fixed to the rear end side (right side in FIG. 2) of the output shaft 65 of the drive motor 59 and a scale not shown, and the rear end side of the motor housing 61 (FIG. 2). There is a case 73 fixed to the middle right side) and an electronic board 75 installed in the case 73 and mounted with a projector and a light receiver (not shown). When the encoder wheel 71 is irradiated from a light projector (not shown) on the electronic board 75, the light reflected by the encoder wheel 71 is detected by the light receiver (not shown). When the encoder wheel 71 is rotated by the scale (not shown), the intensity of light detected by the light receiver (not shown) changes, and the rotation angle or rotation of the output shaft 65 is changed based on the change in the light intensity. Numbers are to be detected.

  A controller board 77 is installed on the upper right side of the motor case 11 in FIG. The controller board 77 controls the rotational direction and rotational speed of the drive motor 59.

  A ball screw shaft 79 is installed in the frame 5 in a state of being rotatably supported by the bearings 37 and 37. The ball screw shaft 79 includes a ball screw shaft main body 81 and a support portion 83 protruding from the rear end side (right side in FIG. 2) of the ball screw shaft main body 81. A spiral groove 85 is formed on the outer peripheral surface of the ball screw shaft main body 81. The support portion 83 is press-fitted into the inner rings 41 and 41 of the bearings 37 and 37. The support portion 83 projects from the bearings 37, 37 to the rear end side (right side in FIG. 2), and is connected to the output shaft 65 of the drive motor 59 via a coupling mechanism 87. The coupling mechanism 87 includes a ball screw shaft side hub 89 fixed to the support portion 83 of the ball screw shaft 79, a motor side hub 91 fixed to the output shaft 65 of the drive motor 59, and the ball screw shaft. The intermediate disc 93 is engaged and inserted between the side hub 89 and the motor side hub 91.

  A ball screw nut 95 is screwed onto the ball screw shaft 79. The ball screw nut 95 has a substantially cylindrical ball screw nut body 97, and a spiral groove 99 is formed inside the ball screw nut body 97. The ball screw nut main body 97 is formed with an unloaded circulation path (not shown). A flange portion 101 is formed on the rear end side (right side in FIG. 2) of the ball screw nut main body 97.

  An end cap 103 is installed on the front end side (left side in FIG. 2) of the ball screw nut body 97, and an end cap 105 is also installed on the rear end side (right side in FIG. 2) of the ball screw nut body 97. ing. Each of the end caps 103 and 105 is formed with a return path (not shown).

  The space between the spiral groove 99 of the ball screw nut body 97 and the spiral groove 85 of the ball screw shaft body 81, the return path (not shown) of the end cap 103, the unloaded circulation path (not shown), and the end A plurality of steel balls 106 roll and circulate in a return path (not shown) of the cap 105.

A rod connecting member 107 is installed on the outer peripheral side of the ball screw nut 95. The rod connecting member 107 includes a rod connecting member main body 109 and a rod fixing member 111. The rod connecting member main body 109 has a substantially cylindrical shape at the rear end side (the right side in FIG. 2), and the ball screw nut 95 is accommodated and fixed therein. The flange portion 101 of the ball screw nut main body 97 is engaged with the rear end side (right side in FIG. 2) of the rod connecting member main body 109 and is fixed by the ball screw nut fixing member 112 from the outside (right side in FIG. 2). Yes.
The front end side (left side in FIG. 2) of the rod connecting member main body 109 has a substantially semi-cylindrical shape in which the upper side in FIG. 2 is cut out, and the rod fixing member 111 is installed here.

A hollow rod 113 is connected to the front end side (left side in FIG. 2) of the ball screw nut 95 via the rod connecting member 107. The hollow rod 113 is a substantially cylindrical member, and its rear end (right side in FIG. 2) is inserted and fixed by the rod connecting member main body 109 and the rod fixing member 111.
A tip member 115 is fixed to the tip of the hollow rod 113 (left end in FIG. 2), and an attachment object (not shown) is attached through the tip member 115.
Further, the distal end side (left end side in FIG. 2) of the hollow rod 113 penetrates the through hole 17 of the front cap 7 and protrudes forward (left side in FIG. 2). The hollow rod 113 is slidably supported by a sliding bearing 23 installed on the front cap 7.

  Further, non-rotating protrusions (not shown) protrude and are formed on both sides of the rod connecting member main body 109 in the width direction (perpendicular to the paper surface in FIG. 2). It is engaged with a guide groove (not shown) formed on the inner peripheral surface. With such a configuration, even when the ball screw shaft 79 is rotated, the rotation of the ball screw nut 95 and the hollow rod 113 is restricted and moved in the front-rear direction (left-right direction in FIG. 2).

  An oil supply cap 121 is detachably installed in the oil supply hole 49 of the rear bracket 9. The oil supply cap 121 is made of, for example, rubber and has an elliptical cross-sectional shape as shown in FIG. 4A. The plug portion 123 whose diameter is reduced in the lower side in FIG. The upper part in FIG. 4A is an enlarged lid part 125. When the oil supply cap 121 is attached, the plug portion 123 side is press-fitted into the oil supply hole 49, and the vicinity of the opening of the oil supply hole 49 is covered by the lid portion 125.

A slit 127 as an air vent is formed on the upper side in FIG. The slit 127 serves as a ventilation portion that communicates the inside and outside of the fuel cap 121. Further, as shown in FIG. 4B, a recess 129 is formed in the inner portion (the lower portion in FIG. 4B) of the slit 127 of the oil supply cap 121.
In addition, annular convex portions 131 and 131 are projected and formed on the outer peripheral side of the plug portion 123. The annular protrusions 131 and 131 are brought into contact with the inner peripheral surface of the oil supply hole 49 when the plug 123 is press-fitted into the oil supply hole 49, whereby the oil supply cap 121 is held in the oil supply hole 49. Is done.

  A filter (not shown) is detachably installed in the recess 129. There are various types of filters, such as those that do not allow dust to pass through and those that do not pass moisture but allow air to pass through.

Next, the operation of this embodiment will be described.
First, the operation of the actuator 1 will be described.
When the ball screw shaft 79 is rotated forward or reverse by the drive motor 59, a force is applied so that the ball screw nut 95 and the hollow rod 113 are also rotated. However, the rotation of the ball screw nut 95 and the hollow rod 113 around the ball screw shaft 79 is restricted by the non-rotating convex portion (not shown) of the rod connecting member 107 and the guide groove (not shown) of the frame 5. Therefore, it moves forward or backward along the guide groove (not shown).
Further, when the ball screw nut 95 and the hollow rod 113 are advanced or retracted, air enters and exits the housing 3 from the slit 127 of the oil filler cap 121, thereby reducing the change in air pressure in the frame 5. . As a result, the ball screw nut 95 and the hollow rod 113 are smoothly advanced or retracted.

  In addition, a filter (not shown) is detachably installed in the recess 129 of the oil supply cap 121. When the air enters and exits through the slit 127, the filter does not allow, for example, dust to pass or moisture does not pass. However, it performs various functions such as allowing air to pass through.

Next, oil supply to the ball screw shaft 79 and the ball screw nut 95 will be described.
First, the fueling cap 121 is removed. The oil cap 121 is removed by inserting a jig (not shown) such as a flat-blade screwdriver into the slit 127 and lifting the oil cap 121 toward the outside of the housing 3.
When the oil supply cap 121 is removed in this manner, the outside of the actuator 1 and the inside of the frame 5 are communicated with each other through the oil supply hole 49 and the recess 51 of the rear bracket body 25.
Next, a nozzle of an oil supply spray (not shown) is inserted through the oil supply hole 49, the surface of the ball screw shaft 79, the space between the ball screw shaft 79 and the ball screw nut 95, and a guide groove (not shown) of the frame 5. In addition, grease (not shown) is supplied to a space between a rotation stopper (not shown) of the ball screw nut 95 and a guide groove (not shown) of the frame 5.
When refueling is completed, the plug portion 123 of the refueling cap 121 is press-fitted into the refueling hole 49 and the refueling cap 121 is attached.

Next, the effect of this embodiment will be described.
First, the oil supply cap 121 is detachably attached to the oil supply hole 49 of the actuator 1, and the oil supply cap 121 is provided with a slit 127 as an air vent, so that the housing 3 is separated from the oil supply hole 49. There is no need to provide a vent hole, and the configuration for refueling and the configuration for venting air during operation can be simplified.
Further, only the slit 127 is formed as an air vent, and the configuration can be simplified.
Further, since the slit 127 is a ventilation portion that communicates the inside and outside of the oil supply cap 121, the configuration for air bleeding can be made very simple.
Further, the slit 127 is always open, and the pressure change in the housing 3 can be surely released through the slit 127 when the actuator 1 is operated.
Further, since the recess 129 is provided inside the oil cap 121, the oil cap 121 can be easily deformed and can be easily attached to and detached from the oil hole 49.
In addition, since a filter (not shown) is detachably mounted in the recess 129, for example, a filter having a function of not allowing dust to pass through, not allowing moisture to pass therethrough but allowing air to pass therethrough, can be used to intrude foreign matter. Prevention can be made more reliable.

The present invention is not limited to the one embodiment.
Various cases such as a circle and an oval are conceivable as the shape of the slit provided in the oil filler cap.
Further, instead of the slit, for example, an incision may be made in the oil supply cap as a valve to function as a valve. In this case, the valve is opened by a pressure change in the housing only when the ball screw nut and the hollow rod are advanced and retracted, and in other cases, the valve is closed to ensure that foreign matter enters from the outside. Prevention can be achieved.
Moreover, the case where a filter is not installed in the said oil supply cap is also considered.
Moreover, the case where an oil supply hole is provided in the flame | frame side is also considered. In addition to spraying, refueling may be performed by a grease gun, for example.
In addition, the illustrated configuration is an example, and various cases are conceivable.

  The present invention relates to a rod-type actuator, and relates to a device designed to simplify the configuration for refueling and air bleeding during operation, and is suitable for an actuator used for an industrial robot, for example. It is.

DESCRIPTION OF SYMBOLS 1 Actuator 3 Housing 49 Oil supply hole 59 Drive motor 95 Ball screw nut 113 Hollow rod 121 Oil supply cap 127 Slit (Air venting part, ventilation part)
129 recess

Claims (6)

A housing;
A ball screw shaft built in the housing and rotated and driven by a drive motor;
A ball screw nut screwed to the ball screw shaft in a state where its rotation is restricted;
A hollow rod fixed to the ball screw nut;
Comprising
In an actuator that rotates the ball screw shaft in the same direction by rotating the drive motor in the appropriate direction, thereby moving the ball screw nut and the hollow rod back and forth in the axial direction of the ball screw shaft. ,
The housing is provided with an oil supply hole, and an oil supply cap is detachably attached to the oil supply hole.
An actuator characterized in that an air vent is provided in the oil filler cap. The actuator according to claim 1, wherein
The actuator according to claim 1, wherein the air venting part is a ventilation part provided in the oil supply cap and communicating between the inside and the outside. The actuator according to claim 2, wherein
The actuator according to claim 1, wherein the ventilation portion is always open. The actuator according to claim 2, wherein
The actuator according to claim 1, wherein the ventilation portion is opened when an internal pressure is applied. In the actuator according to any one of claims 1 to 4,
An actuator characterized in that a recess is provided inside the air vent of the oil cap. The actuator according to claim 5, wherein
An actuator characterized in that a filter is detachably mounted in the recess.

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