JP5908216B2 - Linear motion guide mechanism - Google Patents

Description

  The present invention relates to a linear motion guide mechanism used for guiding a linear advance / retreat member that advances and retreats on a straight line in a machine tool, a measuring device, a conveyance device, and the like.

  As a part used for linear motion guidance in a positioning part of a machine tool or the like, for example, as shown in FIG. 17, a linear rail guide (a combination of a linear rail 30 and a slide unit 31 that slides along the linear rail 30 is provided. Also called linear motion rolling bearing). A variety of products having different sizes, shapes, and the like are sold by manufacturers, and it is possible to select an appropriate linear rail guide that meets the application conditions such as load load and use posture.

  Currently, there are two types of linear rail guides that are widely used. One is a circulation type in which rolling elements (not shown) such as balls and rollers in the linear rail guide circulate inside the slide unit 31. The other type is a finite stroke type in which rolling elements called cross roller guides are constrained by a cage. Both types use a hardened steel material such as bearing steel for the linear rail 30 or the rolling element that serves as a guide surface, thereby improving durability. As shown in the example of FIG. 17, the ball screw mechanism and the linear rail guide are combined and installed in parallel with each other, so that radial load and moment load are not directly applied to the ball screw mechanism, and durability performance is improved. Excellent and highly accurate linear motion guidance can be realized.

  As a method of linear motion guidance without using a linear guide rail, Patent Documents 1 to 4 provide vertical grooves and vertical guide surfaces on the inner surface of the housing and the like, and a bearing such as a cam follower is rotated along these vertical grooves and vertical guide surfaces. Technologies have been proposed to achieve linear motion guidance by running. Patent Document 5 proposes a technique for realizing linear motion guidance by providing a plurality of bearings arranged in the circumferential direction on the housing side and applying the outer ring surface of these bearings to a linearly advancing / retracting member disposed at the center. Has been.

JP 2007-216280 A Japanese Patent Laid-Open No. 2-186157 JP 2010-179323 A JP 2007-333046 A JP 2001-221229 A

  As shown in FIG. 18, the cylinder type linear actuator 7 driven by the motor 6 is increasingly used in production facilities and transfer facilities as an alternative to air cylinders for the purpose of energy saving. In the cylinder type linear motion actuator, the linear motion guide mechanism to be used is important, and the linear motion guide mechanism is a main factor that determines the appearance, cost, and performance of the cylinder type linear motion actuator.

  Although the linear guide mechanism using the linear rail guide has a high rigidity and straight guide structure, it is necessary to fix the linear rail 30 with a number of fixing tools 32 such as bolts as shown in FIG. It becomes an obstacle to promote the cost reduction and cost reduction.

The linear motion guide mechanism that does not use a linear rail guide has the following problems.
In Patent Documents 1 to 4, the main purpose is to prevent rotation of a linear motion member in a mechanism that converts rotational motion into linear motion (Patent Documents 1 and 2), and to be able to receive a load. Although there is a main purpose (Patent Documents 3 and 4), the latter also has a limit in the load direction that can be received due to the number and arrangement of bearings. In particular, the structure cannot be applied to a load from an oblique direction.

  In the case of Patent Document 5, it is possible to receive loads from various directions, but the method of fixing the bearing and the adjustment of the pressing pressure to the linear advance / retreat member of the bearing are complicated.

An object of the present invention is to provide a linear motion guide mechanism that can receive loads from various directions, has high rigidity, has high linear motion accuracy, and can be configured compactly.
Another object of the present invention is to provide a linear actuator that can receive loads from various directions, has high rigidity, has high linear motion guide accuracy, and can be configured compactly.

Linear guide mechanism of the first invention in this inventions includes a tubular housing closed cross-sectional shape, and a screw shaft which is immovably supported rotatably and axially to the shaft around the center in the housing, A linear motion body including a nut screwed to the screw shaft and moved in the axial direction of the screw shaft by rotation of the screw shaft. In the linear motion guide mechanism, a plurality of guide surfaces along the axial direction set of the screw shaft on an inner surface of the housing vignetting, the plurality of guide surfaces becomes two by two side pairs, two guide surfaces comprising these pairs is facing the back in a non-parallel to one another, the plurality of the guided body in contact respectively to the each guide surface in the linear motion body is set vignetting, the plurality of guided body is yield capacity in said housing, said translatory bodies are The shaft has a shaft protruding in the axial direction from the axial end of the housing, and the guided body has a support shaft that protrudes from the outer surface of the linear motion body, and an outer peripheral surface that is attached to the support shaft. A guide bearing comprising a rolling bearing in rolling contact with the guide surface, wherein the guide surface provided on the inner surface of the cylindrical housing has a curved surface that is convex in an arc shape in a cross section perpendicular to the axial center of the screw shaft. and characterized in that

  According to this configuration, by rotating the screw shaft, the linear motion body including the nut moves in the axial direction of the screw shaft. At this time, the plurality of guided bodies provided on the linear moving body are moved in contact with the plurality of guide surfaces provided on the housing, respectively, so that the linear moving body is accurately guided in the axial direction of the screw shaft. .

  Each of the plurality of guide surfaces forms a pair, and the two guide surfaces that form a pair are not parallel to each other and face each other, so that the load acting on the linear motion body is distributed by each guide surface. I can receive it. Therefore, it can receive loads from various directions and large loads. In addition, the two guided bodies that are in contact with the two guide surfaces facing each other are in a state of sandwiching the portion of the housing that is sandwiched between the two guide surfaces, thereby improving the rigidity. Since the guide surface is provided on the inner surface of the housing and it is not necessary to provide a separate rail for guiding the guided body, a compact configuration can be achieved.

Before Symbol guided body includes a support shaft, wherein provided to protrude from the outer surface to the linear motion body, it shall be the guide bearing outer circumferential surface mounted on the support shaft is composed of a rolling contact rolling bearing with the guide surface.
When the guided body is a guide bearing composed of a support shaft and a rolling bearing, the frictional resistance between the guide surface and the guided body is small, and the linear motion body can be moved smoothly.

It said pair of guide surfaces may be kicked multiple set so as to be positioned on both sides of the diameter direction of the screw shaft.
With this configuration, the load acting on the linear motion body can be supported by each pair of guide surfaces with a good balance.

If the housing has a flat bottom surface, wherein each guiding surface may also be inclined obliquely with respect to the bottom surface. The inclination angle of the guide surface may be determined according to the load condition .
A linear motion guide mechanism according to a second aspect of the present invention includes a cylindrical housing having a closed cross-sectional shape, a screw shaft supported by the housing so as to be rotatable about an axis center and immovable in an axial direction, A linear motion guide mechanism including a nut that is screwed onto the screw shaft and moved in the axial direction of the screw shaft by rotation of the screw shaft;
A plurality of guide surfaces along the axial direction of the screw shaft are provided on the inner surface of the housing, and each of the plurality of guide surfaces forms a pair. A plurality of guided bodies that face each of the guide surfaces are provided on the linear moving body, the plurality of guided bodies are accommodated in the housing, and the linear moving body is disposed from the axial end of the housing. The shaft has a shaft protruding in the axial direction, and the guided body includes a support shaft that protrudes from the outer surface of the linear motion body, and a rolling bearing that is attached to the support shaft and whose outer peripheral surface is in rolling contact with the guide surface. A plurality of pairs of guide surfaces located on both sides of the screw shaft in the diametrical direction, and the axis of the support shaft is orthogonal to the axis of the screw shaft and the support shaft Offset to a straight line parallel to the axis of It is door.

Wherein the axis of the support shaft is perpendicular to the axial center of the screw shaft may be offset relative to the axis and a straight line parallel to the support shaft.
By adopting the above configuration, it becomes possible to receive a wider variety of loads, and it is possible to achieve load distribution and improvement of housing strength.

The guided body may also be kicked plurality set side by side in the axial direction of the screw shaft to the linear motion body.
In this case, the load capacity can be increased.

The plurality of the guided body can be disposed to be shifted from each other in the axial direction of the screw shaft to the linear motion body.
In this case, it is possible to arrange the guided bodies that meet the load conditions.

When the guided body is composed of the nut and a moving bracket fitted to the outer periphery of the nut, the guided body on the side surface of the moving bracket is determined so that the axial center of the screw shaft does not coincide with the center of the moving bracket. the screw shaft provided no point may be placed.
Even if the axis of the screw shaft does not coincide with the center of the moving bracket, the guided body is moved by rotating the screw shaft. Therefore, it is possible to arrange | position a screw shaft in the location where the to-be-guided body is not provided in the side surface of a moving bracket, and the freedom degree of arrangement | positioning of each component in a housing increases by it.

The guide bearing of the guided body may be a deep groove ball bearing.
Deep groove ball bearings are easy to assemble, are easily available, and are low cost.

In addition, the guide bearings of the guided body may be angular ball bearings that are arranged in the axial direction on the support shaft and provided in a rear combination or a front combination, and preload may be applied to the plurality of angular ball bearings.
When the rolling bearing is a double row angular contact ball bearing, in addition to a load in a direction perpendicular to the guide surface, a load in the width direction of the guide surface can be received. Further, by applying the preload, it is possible to increase the rigidity by eliminating the gap between the bearings.

The guide bearing of the guided body may be a cam follower in which a roller that also serves as an outer ring is provided on the outer periphery of the support shaft via a rolling element.
The cam follower can increase the width of the outer ring as compared with a ball bearing of a deep groove ball bearing or an angular ball bearing, and therefore can improve the load capacity of a single unit. When the rolling element is made of a roller such as a cylindrical roller, the load capacity can be further improved. Further, since the cam follower does not have an inner ring, the cam follower can be arranged in a narrow space in the diameter direction.

A resin coating may be applied to the outer peripheral surface of the outer ring in the guide bearing of the guided body.
Thereby, the slidability between the outer ring of the guide bearing and the guide surface of the housing can be improved.

The guide surface is arcuate be convex song surface at which if in a cross section perpendicular to the axial center of the screw shaft, with respect to the guide surface, is avoided that the outer peripheral surface of the outer ring of the guide bearing is an edge contact .

Within the width in contact with the guide bearing in the guide surface, the oil storage groove extending in the axial direction may be eclipsed set.
In this case, the outer peripheral surface of the outer ring of the guide bearing is prevented from running out of lubricating oil, and the durability of the guide bearing can be improved.

Wherein the guide surface between the rolling bearing of the guided body, a plate-like member for abrasion high surface hardness than the guide surface may be interposed. For example, the plate-like member is provided by being attached to the surface of the guide surface.
In this case, it is possible to improve the durability against the surface wear of the guide surface due to the rolling contact of the rolling bearing.

For reference Proposed Example, surface hardening treatment on the surface of the front Symbol guide surface may be subjected.
In this case, the durability of the guide surface can be improved.

For reference Proposed Example, hardened by heat treatment prior Symbol housing may be subjected.
Also in this case, the durability of the guide surface can be improved.

The housing may include a housing body and a guide surface forming member that has the guide surface and is fixed to the housing body.
In this case, the guide surface can be easily processed.

For reference Proposed Example, before Symbol guided body is, the may be a sliding contact member for sliding contact with the guide surface provided to protrude in the linear motion body.
Even if the guided body is a sliding contact member that makes sliding contact with the guide surface, the linear motion body can be accurately guided in the axial direction of the screw shaft.

A linear motion actuator according to the present invention includes any of the linear motion guide mechanisms described above and a drive source that rotates the screw shaft of the linear motion guide mechanism.
Since the linear motion guide mechanism has the actions and effects described above, the linear motion actuator to which this linear motion guide mechanism is applied can receive loads from various directions, has high rigidity, and linear motion guide accuracy. Is good.

Linear guide mechanism of the first invention in this inventions includes a tubular housing closed cross-sectional shape, and a screw shaft which is immovably supported rotatably and axially to the shaft around the center in the housing, and a translatory bodies to be moved in the axial direction of the screw shaft by rotation of the screw shaft comprises a nut screwed on the screw shaft, a plurality of guide surfaces along the axial direction of the screw shaft on an inner surface of the housing is set The plurality of guide surfaces are in pairs, and the two guide surfaces forming a pair are non-parallel to each other and face each other, and are in contact with the respective linear guides and the respective guide surfaces. but set the vignetting, the plurality of the guided body in the housing is yield capacity, the translatory bodies has a shaft projecting in the axial direction from the axial end of the housing, the guided body is Projecting from the outer surface to the linear motion body A guide bearing comprising a support shaft and a rolling bearing attached to the support shaft and whose outer peripheral surface is in rolling contact with the guide surface, and the guide surface provided on the inner surface of the cylindrical housing includes Since it is a curved surface that is convex in an arc shape in a cross section perpendicular to the axis center of the screw shaft, it can receive loads from various directions, has high rigidity, has high linear guide accuracy, and can be configured compactly.
A linear motion guide mechanism according to a second aspect of the present invention includes a cylindrical housing having a closed cross-sectional shape, a screw shaft supported by the housing so as to be rotatable about an axis center and immovable in an axial direction, A linear motion guide mechanism including a nut that is screwed to the screw shaft and is moved in the axial direction of the screw shaft by rotation of the screw shaft, the inner surface of the housing in the axial direction of the screw shaft A plurality of guide surfaces are provided, and each of the plurality of guide surfaces forms a pair, and the two guide surfaces that form a pair are non-parallel to each other and face each other, and each of the guide surfaces faces each of the guide surfaces. A plurality of guided bodies are provided in contact with each other, the plurality of guided bodies are accommodated in the housing, and the linear motion body has a shaft protruding in the axial direction from an axial end portion of the housing, and the guided body The guide body is A guide bearing comprising a support shaft that protrudes from the outer surface of the moving body and a rolling bearing that is attached to the support shaft and whose outer peripheral surface is in rolling contact with the guide surface, and the pair of guide surfaces is the diameter of the screw shaft A plurality of shafts are provided so as to be located on both sides of the direction, and the shaft center of the support shaft is offset with respect to a straight line orthogonal to the shaft center of the screw shaft and parallel to the shaft center of the support shaft. It can receive a load from the direction, has high rigidity, good linear guide accuracy, and can be compactly configured.

Since the linear motion actuator according to the present invention includes any of the linear motion guide mechanisms described above and a drive source that rotates the screw shaft of the linear motion guide mechanism, the linear motion actuator can receive loads from various directions. High rigidity, good linear guide accuracy, and compact configuration.

(A) is the fracture | rupture side view of the linear motion actuator provided with the linear motion guide mechanism concerning one Embodiment of this invention, (B) is the IB-IB sectional drawing. It is the elements on larger scale of FIG. It is the elements on larger scale of FIG.1 (B). It is sectional drawing which shows the example from which the guide surface of a linear guide mechanism differs. It is sectional drawing which shows the further different example of the same guide surface. It is sectional drawing which shows the further different example of the same guide surface. It is sectional drawing which shows the further different example of the same guide surface. It is sectional drawing which shows the example from which the to-be-guided body of a linear guide mechanism differs. It is sectional drawing which shows the further different example of the said to-be-guided body. It is sectional drawing which shows the reference proposal example. It is the fracture | rupture side view which abbreviate | omitted some linear motion guide mechanisms concerning different embodiment of this invention. It is the fracture | rupture side view which abbreviate | omitted some linear motion guide mechanisms concerning further different embodiment of this invention. It is a fracture | rupture front view of the linear guide mechanism concerning different embodiment of this invention. It is a fracture | rupture front view of the linear guide mechanism concerning further another embodiment of this invention. It is a fracture | rupture front view of the linear guide mechanism concerning further another embodiment of this invention. It is a fracture | rupture front view of the linear guide mechanism concerning further another embodiment of this invention. (A) is a cutaway side view of a conventional linear motion guide mechanism, and (B) is a sectional view of the XVIIB-XVIIB. It is a fracture side view of the conventional linear motion actuator.

An embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, the linear motion guide mechanism 1 includes a housing 2, a screw shaft 3 that is supported by the housing 2 so as to be rotatable around the center of the shaft and not movable in the axial direction, and a nut that is screwed onto the screw shaft 3. 4 and a linear motion body 5. The linear motion guide mechanism 1 constitutes a linear motion actuator 7 together with a motor 6 that is a drive source.

  The housing 2 includes a cylindrical linear motion guide portion 2a, a screw shaft support portion 2b coupled to the left and right ends of the linear motion guide portion 2a, and a coupling housing coupled to the tip of the screw shaft support portion 2b. A portion 2c, a shaft support portion 2d coupled to the other left and right ends of the linear motion guide portion 2a, and a lid portion 2e coupled to the tip of the shaft support portion 2d.

  The screw shaft 3 includes a ball screw portion 3a to which the nut 4 is screwed, and a cylindrical surface portion 3b and a male screw portion 3c extending from the ball screw portion 3a to the base end side. The screw shaft 3 has a cylindrical surface portion 3b rotatably supported by a double row support bearing 8 fitted to the inner periphery of the screw shaft support portion 2b of the housing 2. The support bearing 8 is a rolling bearing such as an angular ball bearing. A retaining nut 9 is screwed onto the male screw portion 3c, and the axial movement of the screw shaft 3 is restricted. The screw shaft 3 is coupled to a rotating shaft 6 a of the motor 6 installed outside the housing 2 through a coupling 10 housed in a coupling housing portion 2 c of the housing 2.

  The nut 4 is, for example, a ball nut that circulates a ball (not shown) along a contact surface with the ball screw portion 3a of the screw shaft 3, and the ball screw portion 3a and the nut 4 constitute a ball screw mechanism 11. To do. The ball screw mechanism 11 rotates the screw shaft 3 so that the linear motion body 5 including the nut 4 moves in the axial direction.

  The linear motion body 5 includes the nut 4, a moving bracket 12 fitted to the outer periphery of the nut 4, and a shaft 13 extending from the moving bracket 12 in the axial direction of the screw shaft 3. The nut 4 and the moving bracket 12 are coupled to each other so as not to rotate with each other by a spline or the like, and are not movable in the axial direction with respect to a retaining means (not shown). As shown in FIG. 2, the shaft 13 has a cylindrical shape, and a distal end portion protruding from the nut 4 of the screw shaft 3 is inserted into the hollow portion. The shaft 13 is supported so as to be slidable in the axial direction of the screw shaft 3 by a linear sliding bearing 14 fitted to the inner periphery of the shaft support portion 2 d of the housing 2. The moving bracket 12 and the shaft 13 may be integrated or separate. Further, the linear motion body 5 may have the shaft 13 attached to the nut 4 without having the moving bracket 12. Further, an output member (not shown) corresponding to the shaft 13 may be provided integrally with the nut 4 without having the shaft 4 separate from the nut 4.

As shown in FIG. 1B, the linear motion guide portion 2a of the housing 2 has a cylindrical shape having a substantially square cross section perpendicular to the axial direction of the screw shaft 3, and has a constant width along the axial direction of the screw shaft 3 on the inner surface thereof. A plurality of guide surfaces 15 (15A to 15D) are provided. Each guide surface 15 is for guiding a guided body 16 described later in the axial direction of the screw shaft 3. In the example shown in the figure, a total of four guide surfaces 15 are provided, one on each side. Each of the plurality of guide surfaces 15 is arranged in pairs, that is, a guide surface 15A and a guide surface 15B, and a guide surface 15C and a guide surface 15D, respectively, and each pair of guide surfaces 15 is not parallel to each other. They are facing each other. That is, each pair of guide surfaces 15 has a width surface that intersects with each other on its extension line. Each pair of guide surfaces 15 is inclined with respect to the flat bottom surface F of the housing 2 at angles of plus 45 ° and minus 45 ° (θ _A , θ _B , θ _C , θ _D = 45 °).

  The moving bracket 12 of the linear motion body 5 is provided with guided bodies 16 that are in contact with the guide surfaces 15 respectively. The guided body 16 is a guide comprising a trunnion shaft-like support shaft 17 provided to protrude from the outer surface of the movable bracket 12 and a rolling bearing 18 attached to the support shaft 17 and having an outer peripheral surface rolling to the guide surface 15. It is considered as a bearing. The support shaft 17 of each guided body 16 has its axis P intersecting the axis center O of the screw shaft 3. The rolling bearing 18 of this embodiment is a deep groove ball bearing. The guided body 16 may be provided in a portion other than the moving bracket 12 of the linear moving body 5, that is, the nut 4 or the shaft 13.

  In the linear actuator 7 to which the linear guide mechanism 1 is applied, the linear motion body 5 including the nut 4 is moved in the axial direction of the screw shaft 3 by rotating the screw shaft 3 by driving the motor 6. At this time, the plurality of guided bodies 16 provided on the moving bracket 12 of the linear moving body 5 are moved in contact with the plurality of guide surfaces 15 provided on the housing 2, so that the linear moving body 5 is screw shafts. 3 is guided with high accuracy in the axial direction.

  Each of the plurality of guide surfaces 15 forms a pair, and the two guide surfaces 15 that form a pair are not parallel to each other and face each other, so that the load acting on the linear moving body 5 is applied to each guide surface 15 by a load. Received in a distributed manner. Therefore, it can receive loads from various directions and large loads. In addition, the two guided bodies 16 that are in contact with the two guide surfaces 15 that face each other are pressed against the respective guide surfaces 15 to sandwich the portion of the housing 2 that is sandwiched between the two guide surfaces 15. , Rigidity can be improved. Since a plurality of pairs of guide surfaces 15 are provided so as to be located on both sides of the screw shaft 3 in the diametrical direction, the load acting on the linear motion body 5 can be supported by each pair of guide surfaces 15 with a good balance. . Since the guide surface 15 is provided on the inner surface of the housing 2 and a rail for guiding the guided body 16 does not need to be provided separately, a compact configuration can be achieved.

  In this embodiment, the guided body 16 is a guide bearing including a support shaft 17 and a rolling bearing 18, and the outer ring 18 a of the rolling bearing 18 is in rolling contact with the guiding surface 15, so that the guiding surface 15 and the guided body 16 are Therefore, the linear motion body 5 can be moved smoothly. Further, the deep groove ball bearing used as the rolling bearing 18 is easy to assemble, easily available, and low cost.

  As shown in FIG. 4, the guide surface 15 may be a curved surface that is convex in an arc shape in a cross section perpendicular to the axial center O of the screw shaft 3. In this case, the outer peripheral surface of the outer ring 18 a of the rolling bearing 18 can be prevented from making edge contact with the guide surface 15.

  Further, as shown in FIG. 5, an oil sump groove 20 extending in the axial direction may be provided within a width of the guide surface 15 in contact with the rolling bearing 18. In this case, the outer peripheral surface of the outer ring 18a of the rolling bearing 18 is prevented from running out of lubricating oil, and the durability of the rolling bearing 18 can be enhanced.

  Further, as shown in FIG. 6, a wear-resistant plate-like member 21 having a surface hardness higher than that of the guide surface 15 may be interposed between the guide surface 15 and the rolling bearing 18. For example, the plate-like member 21 is provided by being attached to the surface of the guide surface 15. In this case, durability against surface wear of the guide surface 15 due to rolling contact of the rolling bearing 18 can be enhanced.

Instead of providing the plate-like member 21, the surface of the guide surface 15 may be subjected to surface hardening treatment. Also in this case, the durability of the guide surface 15 can be improved.
Alternatively, the entire housing 2 may be cured by heat treatment. Also in this case, the durability of the guide surface 15 can be improved.

  As shown in FIG. 7, the housing 2 may be composed of a housing main body 2A and a guide surface forming member 22 having a guide surface 15 and fixed to the housing main body 2A. The housing body 2A and the guide surface forming member 22 are fixed by an appropriate method such as bolt fixing. In this case, the guide surface 15 can be easily processed.

  As shown in FIG. 8, the rolling bearing 18 may be an angular ball bearing in which a plurality of the rolling bearings 18 are arranged in the axial direction on the support shaft 17 in a rear combination or a front combination. It is desirable to apply a preload to the plurality of angular ball bearings. If the rolling bearing 18 is a double-row angular ball bearing, in addition to the load in the direction perpendicular to the guide surface 15, a load in the width direction of the guide surface 15 can be received. Further, by applying the preload, it is possible to increase the rigidity by eliminating the gap between the bearings.

  As shown in FIG. 9, the guide bearing constituting the guided body 16 is provided with a roller 24c that also serves as an outer ring via a rolling element 24b on the outer periphery of the support shaft 24a, instead of the combination of the support shaft 17 and the rolling bearing 18. The cam follower 24 may be used. The cam follower 24 can increase the width of the roller 24c, which is an outer ring, as compared with the rolling bearing 18 such as a deep groove ball bearing or an angular ball bearing, and therefore can improve the load capacity of a single unit. When the rolling elements 24b are made of rollers such as cylindrical rollers, the load capacity can be further improved. Moreover, since the cam follower 24 does not have an inner ring | wheel, it can be arrange | positioned in the space narrow in the diameter direction.

  When the guide bearing is in rolling contact with the guide surface 15 such as the rolling bearing 18 and the cam follower 24, the outer peripheral surfaces of the outer rings 18a and 24c of the guide bearing may be coated with a resin such as polyurethane. Thereby, the slidability between the outer rings 18a and 24c and the guide surface 15 can be improved.

Further, the guided body 16 may be in sliding contact with the guide surface 15 as shown in FIG. 10 as a reference proposal example . The guided body 16 is provided with a sliding contact member 26 that is in sliding contact with the guide surface 15 fixed to a support member 25 that is provided on the movable bracket 12 so as to protrude outward. Even if the guided body 16 is in sliding contact with the guide surface 15, the linear motion body 5 can be accurately guided in the axial direction of the screw shaft 3.

As shown in FIG. 11, a plurality of guided bodies 16 may be provided on the linear motion body 5 in the axial direction of the screw shaft 3. Thereby, the load capacity can be increased.
Further, as shown in FIG. 12, a plurality of guided bodies 16 may be arranged on the linear moving body 5 so as to be shifted from each other in the circumferential direction of the screw shaft 3. The plurality of guided bodies 16 may be paired guided bodies 16 or guided bodies 16 belonging to different pairs. In this way, by shifting the positions in the axial direction of the plurality of guided bodies 16 to form a staggered arrangement, the guided bodies 16 can be arranged in accordance with the load conditions.

In the above embodiment, the angles θ _A , θ _B , θ _C , and θ _D with respect to the bottom surface F of the housing 2 of each guide surface 15 are set to plus 45 ° or minus 45 °. Also good. The inclination angle of the guide surface 15 may be determined according to the load condition. For example, in the example of FIG. 13, each pair of left and right guide surfaces 15 is inclined with respect to the flat bottom surface F of the housing 2 at angles of plus 30 ° and minus 30 ° (θ _A , θ _B , θ _C , θ _D = 30 °). In the example of FIG. 14, the inclination angles of the guide surfaces 15 are different, θ _A is plus 45 °, θ _B is minus 15 °, θ _C and θ _D are plus 30 ° and minus 30 °, respectively. Has been.

  13 and 14, the support shaft 17 of all the guided bodies 16 or the axis P of the support shaft 17 of a part of the guided bodies 16 is perpendicular to the axial center O of the screw shaft 3 and is supported. It is offset with respect to a straight line parallel to the axis P of the shaft 17. As a result, it is possible to receive a wider variety of loads, and it is possible to distribute the load and improve the housing strength.

  The shape of the cross section of the linear motion guide portion 2a of the housing 2 perpendicular to the axial direction of the screw shaft 3 is not limited to a polygon such as a square, but is a circle as shown in FIG. 15 or an ellipse (not shown). Also good. The number of pairs of guide surfaces 15 may be three or more as shown in FIG. In short, the shape and arrangement of the housing 2 and the guide surface 15 may be determined in accordance with the location where the linear guide mechanism 1 is used, the posture, the load condition, and the like.

  The axis center O of the screw shaft 3 and the center of the moving bracket 12 do not need to coincide. Even in that case, the linear motion body 5 can be moved by rotating the screw shaft 3. FIG. 16 shows an example of the linear motion guide mechanism 1 in which the axial center O of the screw shaft 3 and the axis Q of the moving bracket 12 do not coincide with each other. In this example, a guided body 16 is provided on the side surface of the moving bracket 12. The screw shaft 3 is arranged at a place where it cannot be used. Thus, since the arrangement of the screw shaft 3 can be arbitrarily determined, the degree of freedom of arrangement of each component in the housing 2 is increased.

DESCRIPTION OF SYMBOLS 1 ... Linear motion guide mechanism 2 ... Housing 2A ... Housing main body 3 ... Screw shaft 4 ... Nut 5 ... Linear motion body 6 ... Motor (drive source)
7 ... Linear actuator 12 ... Moving brackets 15, 15A, 15B, 15C, 15D ... Guide surface 16 ... Guided body 17 ... Support shaft 18 ... Rolling bearing 18a ... Outer ring 20 ... Oil reservoir groove 21 ... Plate-like member 22 ... Guide Surface forming member 24 ... cam follower 24c ... roller (outer ring)
26 ... Sliding contact member F ... Bottom surface of housing O ... Axle shaft center P ... Axle shaft center Q ... Center of moving bracket

Claims (16)

Rotation of the screw shaft including a closed cylindrical housing having a cross-sectional shape, a screw shaft supported by the housing so as to be rotatable about the shaft center and immovable in the axial direction, and a nut screwed into the screw shaft A linear motion guide mechanism including a linear motion body that is moved in the axial direction of the screw shaft,
A plurality of guide surfaces along the axial direction of the screw shaft are provided on the inner surface of the housing, and each of the plurality of guide surfaces forms a pair. A plurality of guided bodies that face each of the guide surfaces are provided on the linear moving body, the plurality of guided bodies are accommodated in the housing, and the linear moving body is disposed from the axial end of the housing. The shaft has a shaft protruding in the axial direction, and the guided body includes a support shaft that protrudes from the outer surface of the linear motion body, and a rolling bearing that is attached to the support shaft and whose outer peripheral surface is in rolling contact with the guide surface. The linear guide is characterized in that the guide surface provided on the inner surface of the cylindrical housing is a curved surface convex in an arc shape in a cross section perpendicular to the axial center of the screw shaft. mechanism.   The linear motion guide mechanism according to claim 1, wherein a plurality of pairs of the guide surfaces are provided so as to be positioned on both sides in the diameter direction of the screw shaft.   3. The linear motion guide mechanism according to claim 2, wherein the housing has a flat bottom surface, and the guide surfaces are inclined with respect to the bottom surface. Rotation of the screw shaft including a closed cylindrical housing having a cross-sectional shape, a screw shaft supported by the housing so as to be rotatable about the shaft center and immovable in the axial direction, and a nut screwed into the screw shaft A linear motion guide mechanism including a linear motion body that is moved in the axial direction of the screw shaft,
A plurality of guide surfaces along the axial direction of the screw shaft are provided on the inner surface of the housing, and each of the plurality of guide surfaces forms a pair. A plurality of guided bodies that face each of the guide surfaces are provided on the linear moving body, the plurality of guided bodies are accommodated in the housing, and the linear moving body is disposed from the axial end of the housing. The shaft has a shaft protruding in the axial direction, and the guided body includes a support shaft that protrudes from the outer surface of the linear motion body, and a rolling bearing that is attached to the support shaft and whose outer peripheral surface is in rolling contact with the guide surface. A plurality of pairs of guide surfaces located on both sides of the screw shaft in the diametrical direction, and the axis of the support shaft is orthogonal to the axis of the screw shaft and the support shaft Offset to a straight line parallel to the axis of Linear guide mechanism that door.   4. The linear motion guide mechanism according to claim 2, wherein the axis of the support shaft is offset with respect to a straight line that is orthogonal to the axis center of the screw shaft and parallel to the axis of the support shaft.   6. The linear motion guide mechanism according to claim 1, wherein a plurality of the guided bodies are provided on the linear motion body side by side in the axial direction of the screw shaft.   6. The linear motion guide mechanism according to claim 1, wherein the plurality of guided bodies are arranged to be shifted from each other in the axial direction of the screw shaft on the linear motion body. 7.   8. The guided body according to claim 1, wherein the guided body includes the nut and a moving bracket fitted to an outer periphery of the nut, and the shaft center of the screw shaft and the center of the moving bracket are arranged. A linear motion guide mechanism in which the screw shaft is disposed at a location where the guided body is not provided on the side surface of the moving bracket as a mismatch.   The linear motion guide mechanism according to any one of claims 1 to 8, wherein the guide bearing of the guided body is a deep groove ball bearing.   9. The angular contact ball bearing according to claim 1, wherein the guide bearing of the guided body is an angular ball bearing in which a plurality of backside combinations or frontal combinations are provided side by side in the axial direction on the support shaft. A linear motion guide mechanism in which preload is applied to the angular ball bearing.   The linear motion guide according to any one of claims 1 to 8, wherein the guide bearing of the guided body is a cam follower provided with a roller that also serves as an outer ring via a rolling element on an outer periphery of the support shaft. mechanism.   11. The linear motion guide mechanism according to claim 1, wherein an outer peripheral surface of the outer ring of the guide bearing of the guided body is coated with a resin coating.   The linear motion guide mechanism according to any one of claims 1 to 12, wherein an oil sump groove extending in an axial direction is provided within a width of the guide surface in contact with the guide bearing.   14. A wear-resistant plate-like member having a surface hardness higher than that of the guide surface is interposed between the guide surface and the rolling bearing of the guided body according to any one of claims 1 to 13. Linear motion guide mechanism. In any one of claims 1 to 14, wherein the housing, the housing body and the made in the guide surface forming member fixed to the housing body has a guide surface linear guide mechanism. A linear motion actuator comprising: the linear motion guide mechanism according to any one of claims 1 to 15 ; and a drive source for rotating the screw shaft of the linear motion guide mechanism.

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