JP3852200B2 - Linear motion device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rectilinear motion device used for industrial machines and the like, and more particularly to a technique for preventing wear such as a dustproof seal band and improving the airtightness of a housing.
[0002]
[Prior art]
2. Description of the Related Art In recent years, various work transfer apparatuses have been introduced into processing plants that perform drilling, milling, and the like on machine parts in order to perform work transfer and positioning with high accuracy. This type of workpiece transfer device is composed of a base fixed to the floor of a factory, a table on which a workpiece is placed and fixed, and, for example, two linear motion devices arranged orthogonally, and the like. When a drive command is output from the apparatus to both linear motion apparatuses, the workpiece on the table is conveyed and positioned at an arbitrary position on two axes (X axis and Y axis) orthogonal to each other.
[0003]
The linear motion device includes a carriage that moves linearly guided by a linear guide, a linear actuator that drives the carriage along the linear guide, and a housing that stores and holds the linear guide, the carriage, and the like. In general, the linear guide is a sliding type using a resin bush with a low coefficient of friction, or a rolling type using a rolling element such as a ball or roller, and the linear actuator is a ball screw or a trapezoidal screw. In addition to a feed screw type using, an oil / pneumatic cylinder, a rack and pinion, a linear motor or the like is well known. Further, in the linear motion device, a transport unit to which a transported object (table or the other linear motion device) is attached protrudes from the carriage, while the housing moves along the movement direction of the carriage to allow the transport unit to move. A slit is formed.
[0004]
In the conventional linear motion device, due to the opening of the slits before and after the transport unit, dust, cutting fluid, etc. intrude into the housing and the smooth operation and expected durability are hindered. There was a risk that drive noise such as a linear actuator would leak outside. Therefore, in the utility model registration No. 2508574 and the Japanese Utility Model Publication No. 8-4995, there is an improved linear motion apparatus in which the slit opening is covered with a flexible sealing band, thereby improving the airtightness of the housing. It is disclosed. In the former, a loop-shaped seal band is fixed to the transport section, and the seal band is fitted into a narrow groove formed at the opening end of the slit for sealing, and is guided to a guide pulley when the carriage moves. And travels in the housing. In the latter, a plate-like seal band is fixed to the housing, and the seal band is curved and stretched in the band insertion hole of the carriage so as to be elastically contacted with the outer edge of the slit of the housing for sealing. .
[0005]
[Problems to be solved by the invention]
In the above-described improved linear motion apparatus, the seal band maintains the hermeticity of the housing, but there are problems such as wear of the seal band and obstruction of carriage movement due to long-term operation. In other words, since the seal band is often made of synthetic resin-impregnated canvas, the surface gradually wears when sliding into the groove in the housing or the band insertion hole of the carriage when the device is in operation, and its sealing function is remarkable. In addition to being damaged, it becomes a source of dust that enters the housing and adheres to the guide surface of the straight guide and the like. In addition, when steel (spring steel, etc.) is used as the material to suppress wear of the seal band, the housing, carriage, and guide roller that are in sliding contact (or rolling contact) with the seal band are worn, and the durability of these members In addition, wear powder such as cast iron or aluminum alloy, which is a material of the housing or carriage, enters the housing. Further, when the seal band or the housing or carriage that is in sliding contact with the seal band is worn, the sliding resistance increases due to the roughness of the sliding contact surface, the operating load of the linear actuator increases, and the carriage does not move smoothly.
[0006]
The present invention has been made in view of the above situation, and an object thereof is to provide a linear motion device that achieves wear prevention of a dust-proof seal band and the like and improvement of airtightness of a housing while adopting a relatively simple configuration. To do.
[0007]
[Means for Solving the Problems]
In the present invention, in order to solve the above-mentioned problem, a housing formed with a slit extending in the axial direction that is open to the outside, a linear guide that is installed in the housing and extends in the axial direction, and is guided by the linear guide, A carriage that is disposed in the housing so as to be freely movable in the direction and that has a conveying portion for mounting a conveyed object that protrudes out of the housing through the slit, and the carriage in the axial direction along the linear guide A linear actuator that is moved to the inside of the housing, a loop that is formed through pulleys disposed inside the housing, a movable seal band that is fixed to the transport portion of the carriage and seals the slit, and the slit A pair of lubricant-impregnated materials respectively fitted and held in recessed grooves formed in the housing along both sides of the housing,
Proposed is an airtight linear motion device in which each lubricant-impregnated material is provided with a notch for sandwiching a corresponding side end of the seal band, and forms a lubricating oil film in sliding contact with the front and back surfaces of the side end .
[0008]
According to the present invention, for example, in the case where the seal band is fixed to the carriage, the lubricant is supplied from the lubricant-impregnated material to the seal band every time the seal band travels as the carriage moves. As a result, lubrication is performed on the sliding contact surface between the seal band and the housing, and wear of the both is prevented. At the same time, fine gaps on the sliding contact surface are closed by the lubricant, and the airtightness of the housing is reduced. Improves.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a linear motion apparatus according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an essential part of the first embodiment of the present invention, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. 3 is a sectional view taken along line BB. As shown in these drawings, the rectilinear motion apparatus of the first embodiment includes a housing 1 that is a main body of the apparatus, a pair of rectilinear guides 3 provided in the housing 1, and a front-rear guide (described in the description). For convenience, the carriage 5 moves to the left in FIGS. 2 and 3 and the linear actuator 7 reciprocates the carriage 5 back and forth.
[0010]
The rectilinear guide 3 is a rail ball circulation type rolling guide, and a steel ball (a rail 11 fixed to the upper surface of the housing 1 and a slide member 13 fixed to the lower surface of the carriage 5 circulates in the slide member 13 ( Relative movement as a rolling element. The linear motion actuator 7 is a feed screw type, and an AC servo motor (hereinafter abbreviated as a motor) 17 fixed to the housing 1 via a motor bracket 15 is connected to a ball screw shaft 21 via a coupling 19. When rotationally driven, the rotational motion of the ball screw shaft 21 is converted into linear motion by a ball nut 23 mounted on the lower surface of the carriage 5, and the carriage 5 together with the ball nut 23 as shown by the arrows in FIGS. It has a reciprocating structure. In FIG. 2, reference numerals 25 and 27 denote front and rear rolling bearings that rotatably support the ball screw shaft 21, and reference numeral 29 denotes a bearing housing that holds the rear rolling bearing 27.
[0011]
As shown in FIG. 1, a pair of left and right transport units 33 and 35 are formed on the upper portion of the carriage 5, and a transport target (not shown) is fixed to the transport units 33 and 35. In the housing 1, left and right side covers 37 and 39 and a center cover 41 are fastened and integrated by bolts (not shown), and the left and right transport portions 33 and 35 are connected to the side covers 37 and 39 and the center cover 41. It moves back and forth in the slits 43 and 45 formed therebetween.
[0012]
In the case of the first embodiment, a loop-shaped seal band 47 whose perspective is shown in FIG. 4 is locked and secured to the left and right transport parts 33 and 35 so as to cover both the slits 43 and 45. The seal band 47 is a press-formed product of a thin steel plate, and is formed with a rectangular hole 48 into which the conveying portions 33 and 35 are fitted, and a pair of pin holes 49 before and after the rectangular hole 48. A pair of upper and lower guide pulleys 50 are rotatably supported on the motor bracket 15 and the bearing housing 29, and the seal band 47 travels in the housing 1 as guided by the guide pulleys 50.
[0013]
As shown in FIG. 5 (enlarged view of part C in FIG. 1), the opening ends of the slits 43 and 45 (that is, the end portions of the side covers 37 and 39 and the center cover 41) have side ends of the seal band 47. The recessed grooves 51 and 53 to be inserted are formed, and the lubricant impregnated material 55 is inserted and held in the recessed grooves 51 and 53. The lubricant-impregnated material 55 has a substantially U-shaped cross section with a notch 57 formed in the central portion in the vertical direction, and the seal band 47 enters the notch 57 to be sandwiched between the lubricant-impregnated material 55. ing. In FIG. 1, reference numeral 59 denotes a sound absorbing material held by the center cover 41.
[0014]
As the material of the lubricant impregnated material 55, the lubricating compositions described in JP-A-7-118684, JP-A-7-150163, and JP-A-8-27475 according to the present applicant are suitable. . As described in detail in each publication, these lubricating compositions are obtained by uniformly holding a large amount of lubricant (lubricating oil or grease) in a porous cross-linked resin composition and holding it on the surface. The lubricated lubricant bleeds stably over a long period of time.
[0015]
The operation of the first embodiment will be described below.
When the linear motion device is incorporated in a workpiece transfer device or the like and a current is supplied to the motor 17 from a drive control device (not shown), the motor 17 rotates forward or reverse depending on the supplied current. The rotational force of the motor 17 is transmitted to the ball screw shaft 21 through the coupling 19, and the carriage 5 moves forward or backward while being guided by the linear guide 3 by the action of the ball nut 23 described above. At this time, the seal band 47 travels while being guided by the guide pulley 50 along with the movement of the carriage 5, and both side ends of the seal band 47 slide while being sandwiched between the lubricant-impregnated materials 55.
[0016]
Thereby, the lubricant exuded from the lubricant impregnating material 55 is continuously supplied to both side ends of the seal band 47, and a lubricating oil film (or grease film) is formed on the surface thereof. As a result, the lubrication between the seal band 47 and the guide pulley 50 is always performed satisfactorily, and the wear of the both hardly occurs even during an operation over a long period of time. Further, since there is no gap between the seal band 47 and the lubricant impregnated material 55 and the airtightness of the housing 1 is improved as compared with the conventional one, the following effects are obtained. For example, when the dust generated from the linear actuator 7 is discharged to the outside, or when dust, moisture or the like is prevented from entering the housing 1, the inside of the housing 1 is evacuated or pressurized by an exhaust device or an air supply device. However, since a sufficient negative pressure or a positive pressure is easily obtained due to high airtightness, it is possible to use a device having a relatively small capacity for these devices. In the conventional device, the driving noise of the linear actuator 7 was easily released to the outside through the gap between the housing 1 (concave groove) and the seal band 47. However, in the linear motion device of the first embodiment, Since there was no gap, the noise reduction material 59 was provided on the center cover 41, and the quietness during operation could be improved.
[0017]
In FIG. 6, the principal part of 2nd Embodiment of this invention is shown by the expanded longitudinal cross-section. Since the second embodiment is obtained by changing a part of the first embodiment, only differences from the first embodiment will be described.
As shown in FIG. 6, in the second embodiment as well, the seal band 47 is sandwiched between the lubricant-impregnated material 55 having a substantially U-shaped cross section, but the lower surfaces of the lubricant-impregnated material 55 and the grooves 51 and 53. An elastic member 61 is interposed between the two. The elastic member 61 is made of spring steel or elastic synthetic resin, and assists when the lubricant-impregnated material 55 clamps the seal band 47. As a result, the degree of adhesion between the seal band 47 and the lubricant impregnated material 55 is increased, the lubricant is more reliably supplied from the lubricant impregnated material 55 to the seal band 47, and the airtightness of the housing 1 is further improved. did.
[0018]
In FIG. 7, the principal part of the first reference example of the present invention is shown in a longitudinal section. Since the overall configuration of the first reference example is the same as that of the first embodiment of the present invention, only differences from the first embodiment will be described.
As shown in FIG. 7, in the first reference example , a pair of upper and lower lubricant-impregnated materials 63 and 65 are arranged in the lower part of the housing 1, and the seal band 47 is formed by these lubricant-impregnated materials 63 and 65. It is sandwiched. On the other hand, the end portions of the side covers 37 and 39 and the center cover 41 are formed with recessed grooves 51 and 53 into which the side ends of the seal band 47 are fitted. There is almost no allowance for the thickness, and naturally the lubricant-impregnated material is not held in the concave grooves 51 and 53.
[0019]
In the case of the first reference example , when the seal band 47 travels as the carriage 5 moves, the lubricant is supplied to both surfaces of the seal band 47 from the lubricant impregnated materials 63 and 65, and the seal band 47 and the guide pulley 50 During the lubrication. In addition, the seal band 47 inevitably comes into contact with the concave grooves 51 and 53 due to bending, deflection, etc. during traveling, but in this case, the lubricant prevents the seal band 47 and the concave grooves 51 and 53 from being worn. Is done. In the present reference example , the lubricant impregnated materials 63 and 65 can be made much larger than the first and second embodiments by arranging them over the entire length of the housing 1. Even if the operation is performed for an extremely long time, there is no possibility that the lubricant is exhausted.
[0020]
In FIG. 8, the principal part of the second reference example of the present invention is shown in a longitudinal section. Since the overall configuration of the second reference example is the same as that of the first embodiment, only differences from the first embodiment will be described.
As shown in FIG. 8, in the second reference example , a pair of upper and lower rotatable lubricant-impregnated rollers 67 and a mountain-shaped lubricant-impregnated material 69 are attached to the motor bracket 15. 67 is in rolling contact with the surface of the seal band 47, and the lubricant-impregnated material 69 is in sliding contact with the back surface of the seal band 47. Thus, when the seal band 47 travels as the carriage 5 moves, the lubricant is supplied to both surfaces of the seal band 47 from the lubricant-impregnated roller 67 and the lubricant-impregnated material 69, and the seal band 47 and the concave groove 51, 53 and the guide pulley 50 are lubricated.
[0021]
9 and FIG. 10 (DD sectional view in FIG. 9), the main part of the third reference example of the present invention is shown in a longitudinal section.
In the linear motion device of the third reference example , unlike the example described above, the seal band 71 is fixed to the housing 1 side. The seal band 71 made of a thin steel plate is curved and stretched in a band insertion hole 73 formed in the carriage 5, thereby elastically contacting the slit outer edge 75 of the housing 1 for sealing. In FIG. 9, reference numeral 77 denotes a synthetic resin sliding seal plate that is inserted into a seal plate insertion hole 79 formed in the carriage 5, and seals a lateral gap 81 between the housing 1 and the carriage 5.
[0022]
As shown in FIG. 10, the band insertion hole 73 has a pair of front and rear upper lubricant-impregnated materials 83 and 85 that are in sliding contact with the upper surface of the seal band 71 and a pair of lower and front lubricant that is in sliding contact with the lower surface of the seal band 71. Impregnating materials 87 and 89 are respectively provided. These lubricant-impregnated materials 83, 85, 87, and 89 are made of the same material as that used in the first embodiment, and are pressed against the seal band 71 by the elastic force of the material itself.
[0023]
In the case of the third reference example , when the linear motion device is operated and the carriage 5 moves, both surfaces of the seal band 71 from the upper lubricant impregnated materials 83 and 85 and the lower lubricant impregnated materials 87 and 89 pressed against the seal band 71 are obtained. Is supplied with lubricant. As a result, the lubrication between the carriage 5 and the seal band 71 is always performed satisfactorily, and both wear hardly occur even during the operation for a long time. Further, since the seal band 71 and the sliding seal plate 77 maintain the airtightness of the housing 1, entry of dust into the housing 1 and leakage of driving noise of the linear motion actuator 7 to the outside of the housing 1 are prevented. The
[0024]
This is the end of the description of the specific embodiment and the reference example , but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the seal band is made of a thin steel plate, but may be made of polyurethane impregnated canvas or the like. Further, a round shaft type or a sliding type may be used as the linear guide instead of the rail ball circulation type rolling guide, and an oil / pneumatic cylinder or rack may be used as the linear motion actuator 7 instead of the feed screw type. An and pinion, a linear motor, or the like may be used. Furthermore, the specific configuration of each part of the linear motion apparatus can be changed as appropriate for convenience in design or manufacture.
[0025]
【The invention's effect】
According to the linear motion device of the present invention, the linear motion is guided by the linear guide, the carriage is formed with a transport unit provided for mounting the transported body, and the carriage is driven along the linear guide. Accommodates and holds the linear actuator, the carriage and the linear guide, and is fixed to either the carriage or the housing with a housing formed with a slit through which the conveying portion passes, and closes the opening of the slit And a lubricant-impregnated material that is fixed to either the carriage or the housing and is in contact with the seal band and supplies a lubricant to the surface of the seal band. The lubricant is supplied from the lubricant-impregnated material to the seal band as it moves, and the seal band and housing At the same time the wear can be prevented by lubrication is performed at the sliding contact surface with the grayed or carriage, fine voids of the sliding contact surface is airtight housing is improved due to be closed by the lubricant.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a main part of a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line AA in FIG.
3 is a cross-sectional view taken along the line BB in FIG.
FIG. 4 is a perspective view of a seal band in the first embodiment.
FIG. 5 is an enlarged view of a portion C in FIG.
FIG. 6 is a cross-sectional view showing a main part of a second embodiment of the present invention.
FIG. 7 is a cross-sectional view showing a main part of a first reference example of the present invention.
FIG. 8 is a cross-sectional view showing a main part of a second reference example of the present invention.
FIG. 9 is a cross-sectional view showing the main parts of a third reference example of the present invention.
10 is a cross-sectional view taken along the line DD in FIG. 9. FIG.
[Explanation of symbols]
1 ··· Housing 3 ··· Linear guide 5 ··· Carriage 7 · · · Linear actuators 33 and 35 ··· Conveyance units 37 and 39 ··· Side cover 41 · · · Center cover 43 and 45 · · · Slit 47 · · · Seal band 50 ·············································································································································································· Lubricant impregnated material 61. Plates 83, 85... Upper lubricant impregnated material 87, 89... Lower lubricant impregnated material

Claims (2)

A housing formed with a slit extending in the axial direction opened to the outside;
A rectilinear guide provided in the housing and extending in the axial direction;
A carriage that is guided by the linear guide, is disposed in the housing so as to be movable in the axial direction, and has a transporting part for mounting a transported body that protrudes out of the housing through the slit;
A linear actuator that moves the carriage in the axial direction along the linear guide;
A loop is formed through pulleys respectively disposed inside the housing, and is fixed to the transport portion of the carriage, and a movable seal band for sealing the slit ;
A pair of lubricant-impregnated materials fitted and held in recessed grooves formed in the housing along both sides of the slit ,
An airtight linear motion apparatus characterized in that each lubricant-impregnated material has a notch for sandwiching a corresponding side end of the seal band, and forms a lubricating oil film in sliding contact with the front and back surfaces of the side end .   2. The airtight linear motion device according to claim 1, wherein an elastic member that presses the seal band against the groove surface is further provided in the groove formed in the housing.

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