JP4633106B2 - Linear motion device - Google Patents

Description

  The present invention relates to a linear motion device.

  Conventionally, as disclosed in Patent Document 1, a shaft, an outer cylinder fitted to the shaft, a rolling element holder provided between the shaft and the outer cylinder, and held by the rolling element holder And a load portion in which the rolling element moves between the rolling groove of the rolling element retainer, the outer cylinder, and the shaft, and the load portion is provided with a non-load portion via a return portion. There is a linear motion device in which a rolling element infinite circulation path is formed by the load portion, the no-load portion, and the left and right return portions.

  By the way, in the linear motion device, in order to smoothly move the rolling elements of the load path to the return part and the no-load part, hook parts that scoop up the rolling elements are provided at both ends of the rolling groove of the rolling element holder. It has been.

  In order to smoothly lift and move the ball to the return part, it is desirable that the scooping inclination angle of the tip is as small as possible. However, the tip becomes thinner as the inclination angle is reduced. Therefore, it is necessary to ensure a certain thickness (generally, rolling element cages are often made of synthetic resin in terms of moldability and cost). ) There is anxiety about strength, and the buttock tends to be thick considering durability.)

  On the other hand, when the tip of the buttock is thickened, the impact at the time of collision between the circulating ball and the tip of the buttock increases by moving the outer cylinder linearly, and a large noise is generated due to the collision. Inevitable.

Japanese Patent No. 3244374

  The present invention has been made in view of the current situation as described above, and provides a linear motion device excellent in practicality capable of extremely reducing noise caused by a collision between a distal end of a buttock and a rolling element.

  The gist of the present invention will be described with reference to the accompanying drawings.

From the shaft 1, the outer cylinder 2 fitted to the shaft 1, the rolling element holder 3 engaged with the inner surface of the outer cylinder 2, and the rolling element 4 held by the rolling element holder 3 And a load portion 6 for moving the rolling element 4 between the rolling groove 5 of the rolling element retainer 3, the outer cylinder 2, and the shaft 1 is provided. A linear motion device which is communicated with a load portion 8 and has a rolling element infinite circulation path formed by the load portion 6, the no load portion 8 and the left and right return portions 7, wherein the rolling element retainer 3 is made of brass. (C3602), phosphor bronze (C5191B), or stainless steel (SUS303) , and the rolling element 4 that moves the load portion 6 is provided at both ends of the rolling groove 5 of the rolling element holder 3. Scissors 9 that can be scooped up and moved to the return part 7 side are respectively provided. The oblique angle α are those of the linear motion device, characterized in that it is set to 0 to 20 °.

  The linear motion device according to claim 1, wherein the scooping inclination angle α of the flange portion 9 is set to 10 to 18.5 °.

  The linear motion device according to claim 1, wherein the outer cylinder 2 is provided with a first load groove 10, and the shaft 1 is provided with a second load groove 11. The part 6 is composed of a rolling groove 5 of the rolling element holder 3, the first load groove 10 and the second load groove 11, and is a ball spline in which a ball is adopted as the rolling element 4. The present invention relates to a linear motion device.

  The linear motion device according to claim 3, wherein the flange portions 9 of the rolling element retainer 3 are connected to each other by a connecting portion 12, and the connecting portion 12 is disposed at the bottom of the second load groove 11. The present invention relates to a linear motion device characterized in that a connecting portion disposing groove 13 is provided.

Further, characterized in that the linear motion apparatus according to any one of claims 1-4, wherein the shaft 1, which is composed of a shaft 15 which is inserted into the hollow shaft member 14 and the hollow shaft member 14 This relates to the linear motion device.

The linear motion device according to claim 5 , wherein the shaft body 15 is inserted into the hollow shaft body 14 in a fitted state.

The linear motion device according to any one of claims 5 and 6 , wherein the shaft body 15 is made of copper alloy or steel.

The linear motion apparatus according to claim 7, wherein the shaft body 15 is made of phosphor bronze .

The linear motion apparatus according to claim 7, wherein the shaft body 15 is made of brass .

The linear motion device according to any one of claims 5 to 9 , wherein the shaft body 15 is composed of a plurality of divided shaft bodies 16.

Moreover, the linear motion apparatus of any one of Claims 1-10 WHEREIN: The said outer cylinder 2 concerns on the linear motion apparatus characterized by being made from steel .

  Since the present invention is configured as described above, it is a linear motion device that is extremely practical and capable of extremely reducing the noise caused by the collision between the tip of the flange and the rolling element.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

By making the rolling element holder 3 made of brass (C3602), phosphor bronze (C5191B) or stainless steel (SUS303) , the tilt angle of the flange 9 is higher than that of a synthetic resin rolling element holder. Even if it is made smaller, the flange 9 is difficult to break. Furthermore, by making the rolling element cage 3 made of a copper alloy, sliding friction with the outer cylinder 2 can be increased, and the vibration damping property of the outer cylinder 2 can be increased.

  Accordingly, by reducing the scooping inclination angle α of the flange 9, the impact when the rolling element 4 collides with the tip of the flange 9 is weakened, as well as vibration due to this impact is further attenuated rapidly. Noise resulting from the collision between the tip of the flange 9 and the rolling element 4 is extremely small as compared with the conventional case.

  For example, when the shaft 1 is composed of the hollow shaft body 14 and the shaft body 15 inserted into the hollow shaft body 14, the shaft 1 is also good due to the sliding friction between the hollow shaft body 14 and the shaft body 15. Thus, it is possible to exhibit a sufficient vibration damping property, and the noise caused by the collision between the tip of the flange 9 and the rolling element 4 is reduced accordingly.

  Specific embodiments of the present invention will be described with reference to the drawings.

  In this embodiment, as shown in FIGS. 1 to 3, the shaft 1, the outer cylinder 2 fitted on the shaft 1, and the rolling element holder 3 provided between the shaft 1 and the outer cylinder 2, The rolling element 4 is held by the rolling element holder 3, and the load section 6 moves the rolling element 4 between the rolling groove 5 of the rolling element holder 3, the outer cylinder 2, and the shaft 1. The load part 6 is communicated with the no-load part 8 through the return part 7, and the rolling part infinite circulation path is formed by the load part 6, the no-load part 8, and the left and right return parts 7. In the linear motion device, the rolling element holder 3 is made of copper alloy or stainless steel, and the rolling element that moves the load portion 6 at both ends of the rolling groove 5 of the rolling element holder 3. The hooks 9 for scooping up the moving body 4 and moving them to the return part 7 are provided, and the scooping inclination angle α of the hook 9 is 0. Are those set to 20 °.

  Each part will be specifically described.

  As shown in FIG. 7, the shaft 1 includes a cylindrical hollow shaft body 14 and a cylindrical solid shaft body 15 inserted into the hollow shaft body 14 and made of a different material from the hollow shaft body 14. Has been. Further, a linear second load groove 11 is formed at each portion of the shaft 1 that comes into contact with the rolling element 4 (ball) disposed in the rolling groove 5 of the rolling element holder 3 described later (that is, a linear load groove 11). This example is a so-called ball spline.)

  Specifically, the hollow shaft body 14 is made of steel, and the solid shaft body 15 is made of a copper alloy (particularly preferably made of phosphor bronze or brass), and is composed of a plurality of divided solid shaft bodies 16. The real shaft body 15 is inserted into the hollow shaft body 14 in a fitted state. In the present embodiment, the solid shaft body 15 is employed as the shaft body 15, but a hollow shaft body in which holes for fluid circulation and the like are appropriately formed may be employed depending on the application. In the figure, reference numeral 17 denotes a set screw.

  Accordingly, when vibration is applied to the shaft 1, the solid shaft body 15 finely moves with respect to the hollow shaft body 14, and the inner surface of the hollow shaft body 14 and the outer surface of the solid shaft body 15, which are different materials, are used. When sliding friction occurs, vibration damping is improved as compared to a general shaft made of a single solid shaft. In this embodiment, the hollow shaft body 14 and the solid shaft body 15 are made of different materials in order to obtain as much vibration damping as possible. However, the same material may be used.

  In other words, the vibration generated when the flange portion 9 and the rolling element 4 collide with each other is satisfactorily damped by the sliding friction between the hollow shaft body 14 and the solid shaft body 15. In particular, in the present embodiment, since the split solid shaft body 16 is employed, friction is generated between the interfaces of the plurality of solid shaft bodies 16, and vibration damping is further improved.

  The outer cylinder 2 is a steel cylindrical body, and a rolling element holder 3 made of a copper alloy (phosphor bronze or brass) is engaged with the inner surface of the outer cylinder 2. Further, a first load groove 10 is provided on a portion of the inner surface of the outer cylinder 2 that comes into contact with the rolling element 4 disposed in the rolling groove 5 of the rolling element holder 3.

  In this case, the vibration damping characteristics of the outer cylinder 2 to which the rolling element holder 3 is attached are smaller than those of a synthetic resin (polyacetal) rolling element holder that is generally used in the past. Therefore, the vibration generated when the collar portion 9 and the rolling element 4 collide with each other is satisfactorily damped.

  In the figure, reference numeral 18 denotes an attachment member for attaching the rolling element retainer 3 to the outer cylinder 2, and 19 denotes a seal member for preventing foreign matter from entering between the shaft 1 and the outer cylinder 2.

  The rolling element cage 3 is a cylindrical body made of copper alloy, and includes a linear rolling groove 5 that constitutes the load portion 6, a semicircular return groove 20 that constitutes the return portion 7, and a no-load portion. 8 and the linear unloaded groove 21 are formed so as to form an elliptical rolling element infinite circulation portion. The rolling element retainer 3 is provided with a total of four rolling element infinite circulation portions comprising the rolling groove 5, the return groove 20 and the no-load groove 21. In the present embodiment, a so-called separate type rolling element retainer composed of a plurality of divided bodies (two divided bodies having a semicircular cross-sectional view (not shown)) is employed. Therefore, the vibration damping characteristic is further increased by the friction at the interface between the divided bodies. Moreover, you may employ | adopt the rolling element holder | retainer 3 made from stainless steel instead of copper alloy.

  The rolling groove 5 is formed as a through groove, and a part of the rolling element 4 disposed in the rolling groove 5 protrudes toward the shaft 1 and can contact the second load groove 11 of the shaft 1. Has been. Accordingly, as described above, the first load groove 10 is formed at the site where the rolling element 4 disposed in the rolling groove 5 is in contact with the inner surface of the outer cylinder 2, so that the rolling element retainer rolls. The load portion 6 is constituted by the groove 5, the first load groove 10 of the outer cylinder 2, and the second load groove 11 of the shaft 1.

  The return groove 20 and the no-load groove 21 are configured as non-penetrating grooves, and the return groove 7 and the inner surface of the outer cylinder 2 constitute the return portion 7, and the no-load groove 21 and the inner surface of the outer cylinder 2 are unloaded. Part 8 is configured. Further, the return groove 20 and the no-load groove 21 are smoothly connected so that there is no step.

  Further, when the outer cylinder 2 is linearly moved with respect to the shaft 1, the rolling element 4 positioned in the load section 6 moves to the no-load section 8 through the return section 7 on the opposite side to the movement direction of the outer cylinder 2. To do. At this time, the rolling elements 4 located in the rolling grooves 5 as the through grooves are formed by scoop-like (rounded triangular shape) flange portions 9 (one side thereof) provided at both ends of the rolling grooves 5. It is scooped up and moved to the return portion 7 which is a non-through groove.

  In the figure, reference numeral 22 denotes an inclined portion provided between the linear first load groove 10 and the return portion 7. The inclination angle β of the inclined portion 22 is the scooping inclination angle α of the flange portion 9. It is set to the following size. In this embodiment, the angle is set to the same angle as the scooping inclination angle α of the collar portion 9.

  In the present embodiment, the scooping inclination angle α of the collar portion 9 is set to 0 to 20 °. Based on the experimental results described later, it has been confirmed that it is preferable to set the angle to 18.5 ° or less. Here, when the scooping inclination angle α is reduced in order to reduce the impact force at the time of collision between the flange 9 and the rolling element 4, insufficient strength of the flange 9 becomes a problem. Since the thing made from a copper alloy is employ | adopted as the moving body holder | retainer 3, sufficient intensity | strength is exhibited.

  Here, the reason why the scooping-up inclination angle α is 0 ° is that, when the flange portion 9 is not linear in a side view, specifically, the tip end side of the flange portion 9 is formed in a curved arc shape protruding downward. This is because, in the case of a so-called R-joint shape in which the end side is a curved arc shape convex upward and both arcs are smoothly connected, the inclination angle at the end of the collar portion 9 is theoretically 0 °.

  In the present embodiment, the shaft 1 and the rolling element holder 3 as described above are employed. However, the rolling element holder 3 has another structure, for example, another example illustrated in FIGS. The end portions of the flange portion 9 are connected to each other by the connecting portion 12, and the bottom portion of the second load groove 11 is provided with a connecting portion disposing groove 13 in which the connecting portion 12 is disposed. It is good also as a structure of.

  In general, for example, as shown in FIG. 3, there is always a minute gap d between the bottom surface of the second load groove 11 of the shaft 1 and the bottom surface of the flange portion 9. It is inevitable that the tip of the rolling element 4 and the rolling element 4 come into contact with each other, but in this alternative example, as shown in FIG. 6, the connecting part 12 and the connecting part (which is deeper than the second load groove 11 of the shaft 1) are arranged. The presence of the groove 13 makes it possible to position the tip of the flange portion 9 in the connecting portion arrangement groove 13 so that the rolling element can be brought up in contact with the inclined middle portion 9a of the flange portion 9 and is brittle. The rolling element 4 does not directly collide with the front end of the flange portion 9, and the scooping can be performed smoothly so that the noise is reduced accordingly.

  In the case of this alternative example, even if the connecting portion 12 is not provided, the flange portion 9 is extended downward as compared with the configuration of FIG. 3, and the tip end of the flange portion 9 is disposed in a groove corresponding to the connecting portion disposing groove 13. The same effect is exhibited, but the strength of the flange portion 9 is lowered by the amount extended downward. Therefore, it is preferable that the ends of the flange portions 9 at both ends are connected and reinforced by the connecting portion 12.

  Since the present embodiment is configured as described above, the rolling element cage 3 is made of a copper alloy, so that the scooping inclination angle of the flange portion 9 is made smaller than that of the synthetic resin rolling element cage. However, the flange 9 is not easily damaged. Furthermore, by making the rolling element cage 3 made of a copper alloy, sliding friction with the outer cylinder 2 can be increased, and the vibration damping property of the outer cylinder 2 can be increased.

  Accordingly, by reducing the scooping inclination angle α of the flange portion 9, the impact force when the rolling element 4 and the end of the flange portion 9 collide is weakened, as well as this impact force is further attenuated rapidly. Noise resulting from the collision between the tip of the flange 9 and the rolling element 4 is extremely small as compared with the conventional case.

  Further, since the shaft 1 is composed of the hollow shaft body 14 and the solid shaft body 15 which is inserted into the hollow shaft body 14 and made of a material different from the hollow shaft body 14, the hollow shaft body 14 and the solid shaft body This shaft 1 can also exhibit a good vibration damping property due to sliding friction with 15, and the noise caused by the collision between the end of the flange 9 and the rolling element 4 is reduced accordingly.

  Therefore, the present embodiment is extremely practical in that the noise caused by the collision between the tip of the flange and the rolling element can be made extremely small.

  An experimental example supporting the effect of the present embodiment will be described.

  Fig. 8 shows the overall sound pressure level (noise level) of a ball spline using a brass rolling element cage that is moved in various ways with different inclination angles of the buttocks. It is a result. In addition, as shown in FIGS. 3 and 6, the straight line to “°” means that the inclined portion of the flange portion 9 has a linear shape in side view.

  It can be seen from FIG. 8 that the noise level is reduced by reducing the tilt angle. In particular, in the straight line 10 ° and the straight line 18.5 °, it was confirmed that the noise can be significantly reduced as compared with the R-linkage at a high speed where the noise is particularly large.

  Further, FIG. 9 shows a resin (polyacetal) cage, a brass (C3602) cage, a phosphor bronze (C5191B) cage and a stainless steel (SUS303) cage, which are made of steel. It is the result of investigating the magnitude of noise when assembled in a cylinder and linearly moved.

  From FIG. 9, it was confirmed that the noise of brass, phosphor bronze (copper alloy cage) and stainless steel cage was smaller than that of the resin cage.

  FIG. 10 shows the result of examining the influence of the sound spectrum exerted by the material of each cage when each of the cages is assembled to a steel outer cylinder.

  From FIG. 10, it was confirmed that the sound pressure level of the brass, phosphor bronze (copper alloy cage) and stainless steel cages was reduced in the entire audible frequency range compared to the resin cage.

  FIG. 11 shows the result of examining the attenuation waveform when each of the cages is assembled to a steel outer cylinder and a predetermined excitation force is applied to the outer cylinder.

  From FIG. 11, it was confirmed that the brass, phosphor bronze (copper alloy cage) and stainless steel cages exhibited superior vibration damping properties compared to the resin cage.

  Moreover, FIG. 12 is the result of investigating the acceleration at the time of attaching each said holder | retainer to the steel outer cylinder, respectively.

  From Fig. 12, brass, phosphor bronze (copper alloy retainer) and stainless steel retainer exhibit broader characteristics and exhibit superior vibration damping than resin cages. Was confirmed.

  FIG. 13 shows the results of examining the damping ratio when each of the cages is assembled to a steel outer cylinder.

  According to FIG. 13, brass, phosphor bronze (copper alloy cage) and stainless steel cages exhibit a greater damping ratio and exhibit superior vibration damping than resin cages. Was confirmed.

  As described above, the inclination angle of the flange portion is set to 18.5 ° or less, and the present embodiment using the copper alloy or stainless steel cage is less in noise than the ball spline using the conventional cage. It has been confirmed that it can be significantly reduced. Further, it was confirmed that a particularly remarkable noise reduction effect can be obtained particularly in the case of stainless steel.

It is a schematic explanatory side view in which a part of the present embodiment is cut out. It is a schematic explanatory sectional drawing of a present Example. It is an expansion schematic explanatory drawing of the principal part of a present Example. It is a schematic explanatory side view in which a part of another example is cut out. It is outline explanatory sectional drawing of another example. It is an expansion schematic explanatory drawing of the principal part of another example. It is the schematic explanatory drawing which notched a part of axis | shaft of a present Example. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result.

1 axis 2 outer cylinder 3 rolling element cage 4 rolling element 5 rolling groove 6 load part 7 return part 8 no load part 9 collar part
10 First load groove
11 Second load groove
12 Connecting part
13 Linkage groove
14 Solid shaft body
15 shaft
16 Split shaft body α

Claims (11)

The rolling element holder includes a shaft, an outer cylinder fitted to the shaft, a rolling element holder engaged with the inner surface of the outer cylinder, and a rolling element held by the rolling element holder. A load portion through which the rolling element moves is provided between the rolling groove, the outer cylinder, and the shaft, and the load portion is communicated with a no-load portion via a return portion. A linear motion device in which a rolling element infinite circulation path is formed between the left and right return portions, and the rolling element cage is made of brass (C3602), phosphor bronze (C5191B), or stainless steel (SUS303). Further, at both ends of the rolling groove of the rolling element cage, hooks for lifting the rolling elements that move the load part and moving them to the return part side are provided, and the rising inclination angle of the hook part Is set to 0-20 ° Apparatus.   2. The linear motion device according to claim 1, wherein a scooping inclination angle of the flange portion is set to 10 to 18.5 degrees.   The linear motion device according to any one of claims 1 and 2, wherein the outer cylinder is provided with a first load groove, the shaft is provided with a second load groove, and the load portion is provided on the rolling element. A linear motion device comprising a rolling groove of a cage, the first load groove and the second load groove, wherein the ball spline adopts a ball as the rolling element.   4. The linear motion device according to claim 3, wherein the flange portions of the rolling element retainer are connected to each other by a connecting portion, and a connecting portion disposing groove in which the connecting portion is disposed is provided at a bottom portion of the second load groove. A linear motion device characterized by being provided. In the linear motion device according to any one of claims 1-4, wherein the axis is linear device, characterized in that it is composed of a shaft 15 which is inserted into the hollow shaft body and the hollow shaft body . 6. The linear motion device according to claim 5 , wherein the shaft body is inserted into the hollow shaft body in a fitted state. The linear motion apparatus according to claim 5 , wherein the shaft body is made of a copper alloy or steel. 8. The linear motion device according to claim 7, wherein the shaft body is made of phosphor bronze. 8. The linear motion device according to claim 7, wherein the shaft body is made of brass. The linear motion apparatus according to any one of claims 5 to 9 , wherein the shaft body is constituted by a plurality of divided shaft bodies. The linear motion apparatus according to any one of claims 1 to 10, wherein the outer cylinder is made of steel.

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