JP2004346987A - Nut for ball screw - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nut for a ball screw which nut can improve stability of the ball screw by giving an appropriate flexibility to the nut so as to cause a stable torque, and to reduce an abnormal operation of the ball screw in operation of the ball screw. <P>SOLUTION: The nut is a kind of structural design of the nut for the ball screw. The nut has slits along its threads in order to reduce its stiffness and to increase its flexibility. By this configuration, a furthermore stable torque is caused and a favorable operation is achieved in operation of the ball screw by absorbing the variation of stress between balls into neighboring threads. In addition, in order to easily machine the nut for the ball screw by reducing the difficulty of machining, the structure of the nut is designed such that the nut can be assembled with two semi-circular nuts. As a result, the manufacturing cost can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural design of a screw canopy in a kind of ball and bolt, and to provide the ball and bolt with stable torque or pressure when the screw canopy moves on the bolt. Can be.
[0002]
[Prior art]
A ball bolt is a type of screw can that drives the machine by moving the bolt, and the screw can move the bolt is to produce relative movement by rolling the ball between the threads. . Therefore, when the ball and bolt are activated, when the screw sheath passes through pitches of different sizes caused by machining errors on the bolt, a sudden stress change occurs, the torque of the ball and bolt fluctuates, and the ball and bolt change. The operation of the bolt becomes unsatisfactory, affecting the stability of the ball bolt.
[0003]
FIG. 5 is a schematic sectional view of a conventional bolt and screw cap assembly. Two screw canopies 50 are fitted on the outside of the bolt 10, and a ball 40 is provided between the two screw canopies 50 that fit with the bolt 10, and the ball 40 interacts with the bolt 10 and the two screw canopies 50. In addition, there is a disc spring 51 in a space where the two screw canopies 50 are joined to each other, which can absorb the torque fluctuation between the two screw canopies 50, smoothing the operation of the ball bolt and increasing the stability. . However, this prior art can only be used with double screw-covered ball bolts and has limited application. In addition, since only the torque fluctuation between the screw cap and the screw cap can be absorbed, improvement is required.
[0004]
FIG. 6 is a schematic sectional view of a conventional bolt and screw cap. A screw canopy 60 fits on the outside of the bolt 10, and a ball 40 is provided between the bolt 10 and the screw canopy 60 to allow the ball 10 and the screw canopy 60 to reciprocate. In addition, there is a bend notch 61 on the outside of the screw canopy 60, and this prior art also increases the deflection of the screw canopy 60 and can absorb the resulting torque, smoothing the operation of the ball bolt and increasing stability. Although the technique can be used with a single screw canopy, it cannot be rolled because there is no ball rolling line near the flex notch on the screw canopy. Therefore, the design of the number and location of the flex notches on the screw cover is considerably limited. In addition, since the function of absorbing the torque fluctuation reaches only on both sides of the screw-covered bending notch, the effect of absorbing the torque is also limited, and improvement is required.
[0005]
[Object of the invention]
SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a kind of ball and bolt screw cover, which allows the screw cover to have a proper deflection, to provide a stable torque when the ball and bolt are operated, and to operate the ball and bolt. Reduces upset and increases ball bolt stability.
[0006]
A further object of the present invention is to provide a kind of ball and bolt screw cover structure, which structure makes the screw cover processing convenient and relatively reduces the manufacturing cost of ball and bolt.
[0007]
[Description of the invention]
The bolts or screw caps of ball bolts have some errors due to processing, have slightly different pitches, produce torque fluctuations and malfunction. Since torque fluctuations due to different pitches when the ball / bolt is actuated do not result in malfunction, the present invention first produces from the Newtonian second law of motion F = KX, with the same error, if the value of K is large. Stress increases. Therefore, the screw cap of the ball and bolt of the present invention reduces the value of the (screw stiffness) F (stress generated) by reducing the K value of the screw cap, and the influence of the stress on the ball and bolt is reduced. Let go down.
[0008]
And the design which reduces the stiffness of the screw canopy according to the present invention reduces the stiffness of the screw canopy and increases the bending by installing a cut groove along the thread of the screw canopy. This absorbs unstable stress differences due to different pitches between balls in adjacent threads. When the ball bolt operates, it has a more stable torque and produces smooth operation. In addition, the present invention takes into account the effect of the depth width ratio of the screw cap groove on the screw cap stiffness and obtains relevant data using a finite element analysis system, for example, as shown in FIG. When the depth-to-width ratio is greater than 2, the stiffness of the screw cap drops significantly.
[0009]
Next, the present invention takes into account the relationship between the degree of deflection of the screw canopy and the location of the kerf, and places a kerf at the top of the thread tooth, or a kerf at the bottom of the tooth, Alternatively, by providing a kerf at the top or bottom of the thread teeth, respectively, the screw sheath can be designed with different kerf positions to provide a suitable degree of deflection.
[0010]
In addition, in the present invention, considering the application of other functions, the position of the cut groove designed along the thread of the screw cover is changed, and the position of the cut groove is installed inside or outside the screw cover, or on both inside and outside. Accordingly, the present invention can be applied not only to the function of stabilizing the torque but also to the function of lubricating the screw sheath or the ball.
[0011]
In addition, in order to make machining of the screw cap structure of the ball and bolt of the present invention convenient and to reduce the difficulty, the screw cover structure design of the present invention can be assembled with two half screw covers and manufacture of the ball and bolt. Reduce costs. If the half-screw cover is manufactured by a mold method and is injected or dewaxed with metal, the manufacturing cost can be greatly reduced.
[0012]
For a better understanding of the features and technical contents of the present invention, refer to the following examples related to the present invention in detail. The examples and schemes are for explanation and reference only and do not limit the invention.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a cross-sectional view of an embodiment of the present invention, which is an example of a screw canopy of an external circulation circuit, in which a helical screw is inserted inside a screw canopy 20 in which a bolt (not shown) is fitted. There is a crest 23, which forms an inner groove 24 along the screw thread 23 to allow the screw canopy 20 to have a considerable deflection, and has a circulation pipe hole 26 on the screw canopy 20, inside the screw canopy thread 23. Ball (not shown) can be circulated and infinite circulation rolling can be performed.
[0014]
FIG. 2 is an assembly view of a second embodiment of the present invention, in which the screw canopy of the external circulation circuit system is taken as an example, in which the screw canopy 20 is composed of upper and lower two-half screw canopies 21 and 22. Assembled, the half screw covers 21 and 22 have fixing holes 25, the screws 30 are fixed in the fixing holes 25, and the two half screw covers 21 and 22 constitute one complete screw cover 20. The screw caps 21 and 22 are formed with a screw thread 23 and an inner groove 24, and the half screw cap 21 has a circulation pipe hole 26 so that the ball (not shown) in the screw cap 20 can be circulated so as to be infinitely circulating. You can roll. The threads 23 on the half-thread canopy 21 and the threads 23 on the half-thread canopy 22 can be combined into a continuous thread, rolling a ball (not shown) thereon. The threads 23 along the half-thread canisters 21 and 22 are provided with kerfs 24 at the top and bottom of the thread teeth, giving the screw-cover 20 better deflection and stress between the balls in adjacent threads 23. The change can be absorbed, the ball / bolt torque does not fluctuate, and the operation of the ball / bolt becomes smooth and the stability increases.
[0015]
FIG. 3 is a schematic sectional view of an assembly of the ball and the screw sheath of the present invention. A screw cover 20 is fitted on the outside of the bolt 10, and a ball 40 for rolling the bolt 10 and the screw cover 20 to each other is installed between the bolt 10 and the screw cover 20. In FIG. The inner groove 24 is formed at the bottom of the screw thread along the screw thread 23, and the screw canopy 20 is bent so that the ball 40 in the screw thread 23 in the axial direction is formed. The torque fluctuation with the ball 40 can be absorbed, the operation of the ball and bolt is smoothly performed, and the stability is increased. In FIG. 3B, the screw canopy 20 has an inner groove 24, the main feature of which is that the inner groove 24 is located at the top of the screw thread along the screw thread 23, so that the screw canopy 20 is bent. The variation in torque between the balls 40 in the thread 23 in the holding axial direction can be absorbed. In FIG. 3C, the screw canopy 20 has an inner groove 24, the main feature of which is that the inner groove 24 is located along both the top and bottom of the screw thread 23 so that the screw can be screwed down. The canopy 20 has a flexure so that a fluctuation in torque between the balls 40 in the screw thread 23 in the axial direction can be absorbed. In FIG. 3 (D), the main feature is an outer groove 29 outside the screw canopy 20, and the outer groove 29 is located along the top and bottom of the screw thread 23, and the screw canopy is provided. 20 can be flexed to absorb the torque fluctuation between the balls 40 in the screw thread 23 in the axial direction. In FIG. 3 (E), an inner groove 24 and an outer groove 29 are located on the inner and outer sides of the screw cover 20, respectively, and the inner groove 24 is located at the bottom of the thread along the thread 23. The outer groove 29 is located along the top of the thread of the thread 23, and the screw canopy 20 is bent so as to absorb the torque fluctuation between the ball 40 and the ball 40 in the thread 23 in the axial direction.・ Smooth bolt operation and increase stability. In FIG. 3 (F), the inner groove 24 of the screw canopy 20 is located at the top of the thread along the thread 23, and the outer groove 29 is located along the bottom of the thread of the thread 23, The screw canopy 20 has a flexure to absorb the fluctuation of the torque between the balls 40 in the screw thread 23 in the axial direction, smoothing the operation of the ball and bolt, and increasing the stability.
[0016]
FIG. 4 is an assembly view of the third embodiment of the present invention. This embodiment also takes as an example the screw canopy of the external circulation circulation system, in which there are fixing holes 25 in the half screw canopies 21 and 22, and the screw 30 is in the fixing hole 25 of the two half screw canopies 21 and 22. Installed through and assemble the two and a half screw canopies 21 and 22 into one complete screw canopy 20. A screw thread 23, an internal groove 24 and a circulation pipe hole 26 are provided on the screw covers 21 and 22, and the balls (not shown) in the screw cover 20 can be circulated in the circulation pipe hole 26 to enable infinite circulation rolling. . The threads 23 on the half-thread canopy 21 and the threads 23 on the half-thread canopy 22 can be combined as a continuous thread, on which a ball (not shown) is rolled. The threads 23 along the semi-threaded canopies 21 and 22 form kerfs 24 at the top and bottom of the thread teeth, giving the screw canopy 20 better deflection. The difference between this example and the previous embodiment is that a plug 27 and a groove 28 are provided at both ends of the two half-screw covers 21 and 22, respectively, so as to assemble the two half-screw covers 21 and 22. Better localization is obtained. In addition, since the screw canopy 20 of this example is vertically symmetrical and is divided into two left and right half screw canopies 21 and 22, the two half screw canopies 21 and 22 are structurally the same and completely the same in the manufacturing process. In addition, the structure facilitates the processing of the screw cover and can reduce the manufacturing cost of the ball bolt.
[0017]
【The invention's effect】
First, the screw canopy of the ball bolt according to the present invention has a cut groove formed in the thread structure of the screw canopy, so that the single screw canopy and the double screw canopy all have an appropriate flexure to absorb fluctuations in the torque of the ball bolt. The operation of the ball bolt can be performed smoothly, and the stability can be increased.
[0018]
Also, the kerf of the screw cap of the ball bolt of the present invention can be arranged on the top or bottom structure of the thread according to the needs, can absorb the torque fluctuation between the balls in the adjacent thread, and also has the kerf. Can be installed on the inside or outside or inside and outside of the screw sheath, and the range of application can be expanded.
[0019]
Besides, the structure of the screw canopy of the ball bolt of the present invention can reduce the manufacturing cost of the ball bolt by assembling one complete screw canopy with two half screw canopies, and convenient processing of the screw canopy. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a ball and bolt screw cover according to an embodiment of the present invention.
FIG. 2 is an assembly view of a ball and bolt screw cover according to a second embodiment of the present invention.
3A to 3F are schematic cross-sectional views of the bolt and screw canopy assembly according to the present invention. FIG. 4 is an assembly view of a ball and bolt screw canopy according to a third embodiment of the present invention. .
FIG. 5 is a schematic sectional view of a conventional bolt and screw cap assembly.
FIG. 6 is a schematic sectional view of a conventional bolt and screw cap assembly.
FIG. 7 is a graph showing the relationship between the depth / width ratio of the cut groove of the screw canopy and the stiffness of the screw canopy.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Bolt 20 Screw canopy 21 Half screw canopy 22 Half screw canopy 23 Thread 24 Inner groove 25 Fixing hole 26 Circulation pipe hole 27 Plug 28 Groove 29 Outer groove 30 Screw 40 Ball 50 Screw canopy 51 Board spring 60 Screw canner 61 Bending cut

Claims (6)

A type of ball bolt screw canopy, with a spiral thread inside the screw canopy that fits with the bolt, and between the above bolt and screw canopy thread. And set up a ball that allows the
On the above-mentioned screw covering, a cut groove is provided along a screw thread, and the ratio of the depth and breadth of the cut groove is 2 or more. The ball / bolt is characterized by absorbing the stress change between the balls in the mountain, giving more stable torque when the ball / bolt is operated, producing smooth operation and increasing the performance stably. Bolt screw covering. 2. The ball vault screw cap of claim 1, wherein the location of the kerf therein is located along the bottom of the thread. 2. The ball vault screw cap of claim 1, wherein the location of the kerf therein is located along the top of the thread. 4. The screw cover of a ball bolt according to claim 1, wherein a position of a cut groove in the screw cover is disposed inside the screw cover. 4. The screw cap of a ball bolt according to claim 1, wherein a position of a cut groove in the screw cap is located outside the screw cover. 4. The ball and bolt screw canopy according to claim 1, wherein the screw canopy structure is formed by assembling two half screw canopies, so that the production cost of the ball and bolt can be reduced. , Ball and bolt screws.

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