JP4026922B2 - Chamfering method for window with built-in deflector of nut screw - Google Patents

Description

[0001]
[Industrial application fields]
The invention of the present application relates to a method for chamfering a deflector built-in window portion of a nut screw, and more specifically, the groove portion of the deflector and the groove portion of the nut screw are smoothly connected, and the ball travels back through the connection portion of these groove portions. The present invention relates to a method for chamfering a deflector built-in window portion of a nut screw, which does not generate noise and vibration by being caught.
[0002]
[Prior art, problems to be solved]
As a screw transmission device, a ball screw (also called a ball screw) is well known, and there are various types.
FIG. 1 shows a cross-section of one type of ball screw 1 therein. In this type, a ball formed by a thread groove 2 a of a shaft screw 2 and a thread groove 3 a of a nut screw 3 ( Steel ball 4) between the adjacent traveling paths in a side view of the traveling path 4 is a return groove 5a formed on the inner peripheral surface of a member called a deflector 5 incorporated in a predetermined portion of the nut screw 3, and a screw of the shaft screw 2. It is communicated by a return travel path formed by the groove 2a and the thread 2b, so that one endless circulation path of the ball 4 is formed between these adjacent travel paths. The deflector 5 is incorporated and attached to a deflector built-in window 3c formed by punching across one screw thread 3b (see FIG. 2) of the nut screw 3.
[0003]
In the ball screw 1 of FIG. 1, two deflectors 5 are incorporated at different positions in the axial direction on the front side and the opposite side of the nut screw 3 in the direction orthogonal to the paper surface. There are four infinite circuits, and 6-1 to 6-4 are also formed (6-2 and 6-4 are not shown). And by such a structure of the ball screw 1, the rotational motion of the nut screw 3 is smoothly converted into the linear motion of the shaft screw 2, and vice versa.
[0004]
2 is a cross-sectional view of the nut screw 3 shown in FIG. 1, with the nut screw 3 removed, FIG. 3 is a partially enlarged view of the ball traveling, and FIG. 4 is a deflector in FIG. FIG. 6 to FIG. 10 are diagrams showing a detailed structure of the deflector 5.
[0005]
Referring to FIGS. 6 to 10, the deflector 5 includes an elongated rectangular substrate portion 5b and a leg portion 5c erected with respect to the substrate portion 5b. The substrate portion 5b has four corners. The portion is cut into a round shape and has two parallel protrusions 5d inclined on both sides in the longitudinal direction. These protrusions 5d are of a height that does not protrude from the outer surface of the nut screw 3 when the deflector 5 is incorporated in the window 3c of the nut screw 3. The return groove 5a is cut out in the leg 5c.
[0006]
In order to incorporate the deflector 5 into the nut screw 3, the deflector 5 is inserted into the deflector assembling window 3c from its leg 5c, and a step at the base of the leg 5c is formed on the inner peripheral wall surface of the window 3c. It is engaged with the stepped portion 3d (see FIGS. 2 to 4), and is caulked symmetrically from the outer surface side of the substrate portion 5b to the appropriate positions 5e and 5e. By this caulking process, the deflector 5 is fixed to the nut screw 3 and displacement of the position of the return groove 5a is prevented.
[0007]
In the ball screw 1 of this type, it is necessary to smoothly connect the connection portion between the normal traveling path and the return traveling path of the ball 4. If the connection of the part is not smooth, the traveling ball 4 is caught in the connection part, and noise and vibration are generated.
[0008]
Among such connecting portions, conventionally, the connecting portion between the screw groove 3 a of the nut screw 3 and the return groove 5 a of the deflector 5 has a dimensional variation in manufacturing the nut screw 3 and the deflector 5, and the deflector of the nut screw 3. Steps were likely to occur due to assembly errors when the deflector 5 was assembled to the built-in window 3c.
[0009]
This will be described with reference to FIGS. 2 to 5. The return groove 5a of the deflector 5 is formed between the adjacent screw grooves 3a and 3a in the side view of the nut screw 3 as shown in FIGS. So that both ends of the opening edges 5af and 5ar (see FIGS. 2, 8, and 10) are adjacent to the nut screw 3. Connecting the return groove 5a to each of the screw grooves 3a, 3a so as to match the window opening edges 3cf, 3cr (see FIGS. 2 and 4) of the screw grooves 3a, 3a is necessary for manufacturing and assembling. It's not easy.
Here, the window opening edge portions 3cf and 3cr are edges formed by hollowing out the deflector built-in window portion 3c across the adjacent screw grooves 3a and 3a of the nut screw 3. Reference numerals 3a and 3a denote edges facing the window 3c.
[0010]
In particular, as shown in FIGS. 2 and 3, of the connecting portions between the opening edges 5 af and 5 ar of the both ends of the return groove 5 a of the deflector 5 and the window opening edges 3 cf and 3 cr of the nut screw 3, Since the connecting portion A on the side far from the screw groove 3a on the side has a long connecting line, a step is likely to appear larger than the connecting portion B on the side close to the screw groove 3a on the other side.
[0011]
5 is a cross-sectional view taken along a plane passing through a contact line with the return groove 5a of the ball 4 and a contact line with the thread groove 3a of the ball 4 in the connection portion A of FIG. As shown, in the connection portion A, there is a step of height v along the window surface of the deflector built-in window 3c between the return groove 5a and the screw groove 3a, and the height w from the return groove 5a. There is a difference in level.
[0012]
Therefore, when such steps v and w are recognized, conventionally, the step of cutting off these steps v and w is performed manually while the deflector 5 is still incorporated in the nut screw 3. The surface alignment between the two grooves (screw groove 3a, return groove 5a) was attempted.
[0013]
However, such manual correction work is not excellent in work efficiency, and it is difficult to completely lose the steps v and w. As a result, the ball 4 is caught by the step and noise is generated. As a result, there is a risk of causing problems, and improvement has been demanded.
[0014]
In the invention of the present application, the groove portion (return groove) of the deflector and the groove portion (screw groove) of the nut screw are smoothly connected by a relatively simple face-to-face processing operation, and the ball travels through the connecting portion of these both grooves. It is an object of the present invention to provide a chamfering method and a chamfering structure for a nut screw deflector built-in window portion so as to prevent occurrence of noise and vibration so as not to be caught.
[0015]
[Means for solving the problems and effects]
The invention of the present application relates to a chamfering method and a chamfering structure of a window incorporated in a deflector of a nut screw, which solves the above-described problems, and the invention described in claim 1 relates to a chamfer of a window incorporated in a deflector of a nut screw. machining methods, before incorporating the deflector to the window portion of the nut screw, a primary chamfer leave a predetermined amount from the opening edge corresponding position of the groove of the deflector when incorporating the deflector to the window portion of the nut screw, the window portion of the nut screw A method of chamfering a deflector built-in window portion of a nut screw, characterized by comprising a secondary chamfer for removing a remaining amount portion after the deflector is assembled.
[0016]
Since the invention described in claim 1 is configured as described above, the method of chamfering the window portion of the nut screw is primarily performed before the deflector is assembled into the window portion of the nut screw, and the nut It is comprised by the secondary chamfering which removes a remaining amount part after incorporating a deflector in the window part of a screw. As a result, the groove portion (return groove) of the deflector and the groove portion (screw groove) of the nut screw are smoothly connected to enable smooth circulation of the ball.
[0017]
Further, the amount of processing for the secondary chamfering is the minimum necessary amount since the primary chamfering is performed prior to the secondary chamfering, and the chamfering work can be efficiently performed as a whole.
[0018]
Further, by configuring the invention according to claim 1 as described in claim 2, since the chamfering of the opening edge portion of the groove portion of the deflector is simultaneously performed at the time of the secondary chamfering, the ball groove further An integral formation can be achieved.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the invention described in claims 1 to 5 of the present application shown in FIGS. 11 to 14 will be described.
FIG. 11 is a diagram showing a situation in which primary chamfering is performed on the deflector built-in window portion of the nut screw in the present embodiment, and FIG. 12 is a primary view of the nut screw deflector built-in window portion. FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12 and shows another primary chamfering state. FIG. 14 is a deflector of the nut screw. It is a figure which shows the secondary chamfering situation after incorporating a deflector in an assembling window part, Comprising: It is sectional drawing cut | disconnected in the same position as FIG.
[0025]
In FIG. 11, a chamfering apparatus 10 that performs the chamfering method for a nut screw deflector built-in window portion according to the present embodiment sets the nut screw 3 on a jig (not shown), and the nut screw 3 has a deflector built-in window opening edge. The grindstone 11 having the shape most suitable for the shape of the portions 3cf and 3cr (3cf is not shown) is used, and the rotation axis thereof is inclined by α (about 10 °) with respect to the central axis of the nut screw 3 and the grindstone 11 is sent in the X direction toward the window opening edge portions 3cf and 3cr, thereby performing primary chamfering of the window opening edge portions 3cf and 3cr.
[0026]
Here, assuming that the deflector 5 is incorporated in the window 3c of the nut screw 3, the chamfering amount of the primary chamfering is left by a predetermined amount from the positions corresponding to the opening edges 5af and 5ar of the both ends of the return groove 5a of the deflector 5 at that time. 12, when the chamfered portion is viewed from the inside of the nut screw 3, the center line of the window portion 3c (same as the cutting line XIII-XIII in FIG. 12) is the window opening edge of the screw groove 3a. The maximum height from the point at which the portions 3cf and 3cr are cut becomes y for the left arc surface and y 'for the right arc surface with the thread groove bottom 3e as a boundary. When viewed from the front arc surface side (corresponding to the right arc surface side in FIG. 12) from the position, it is chamfered so that the maximum radial depth is x (the blackened portions in FIGS. 12 and 13) reference).
The screw groove bottom 3e is a relief surface for the ball 4, and is formed by scraping the bottom of the screw groove 3a with a circle having a diameter smaller than the diameter of the left and right arc surfaces of the screw groove 3a.
[0027]
In the above primary chamfering, the grindstone 11 is fed in the X direction toward the window opening edges 3cf and 3cr, and on the connection portion A side (see FIGS. 2 and 3; the left arc surface side in FIG. 12), If the maximum height y is obtained, the other chamfering amounts y ′ and x are naturally obtained. When the outer diameter of the nut screw 3 is 43.4 mm, the inner diameter is 28.6 mm, the diameter of the left and right circular arc surfaces of the screw groove 3a is 4.36 mm, and the inner dimension of the window portion 3c is 7.0 mm × 16.0 mm, y is about 0.00. The size is 7 mm.
β is the angle (25 °) between the center line of the window 3c and the screw groove 3a, and a is the plane projection distance (1.3 mm) to the contact line between the center line of the screw groove 3a and the screw groove 3a of the ball 4 Indicates.
[0028]
When the primary chamfering process is completed as described above, the secondary chamfering is then performed in which the deflector 5 is incorporated into the window 3c of the nut screw 3 to remove the remaining amount.
As shown in FIG. 14, this secondary chamfering is performed so that the groove surface of the screw groove 3a of the nut screw 3 and the groove surface of the return groove 5a of the deflector 5 are smoothly connected. In addition, a region C of the chamfered portion 3a of the nut screw 3 near the window 3c and a region D of the return groove 5a of the deflector 5 near the opening edges 5af and 5ar are formed by manual work or mechanical grinding. However, the face is corrected. In the illustrated case, in the region C, chamfering is further performed over the width z.
[0029]
In order to incorporate the deflector 5 into the deflector incorporating window portion 3c of the nut screw 3, as described above, the deflector 5 is inserted into the window portion 3c from the leg portion 5c, and the step portion at the base of the leg portion 5c is inserted into the window portion 3c. It is engaged with a step portion 3d formed on the inner peripheral wall surface of the substrate portion 5 and is subjected to a point-symmetric crimping process at appropriate locations 5e and 5e from the outer surface side of the substrate portion 5b. The portion subjected to the caulking process fits tightly with the inner peripheral wall surface of the window portion 3c so that the outer wall surface along the processing direction bulges outward, so that the deflector 5 is firmly fixed to the nut screw 3. The
[0030]
Since the present embodiment is configured as described above, the following effects can be obtained.
The chamfering of the window 3c of the nut screw 3 is performed first before the deflector 5 is assembled into the window 3c of the nut screw 3, and the remaining portion after the deflector 5 is assembled into the window 3c of the nut screw 3. Since the groove portion (return groove 5a) of the deflector 5 and the groove portion (screw groove 3a) of the nut screw 3 are smoothly connected, the ball 4 can be smoothly circulated. Become.
[0031]
Further, at the time of this secondary chamfering, the chamfering of the opening edges 5af and 5ar of both ends of the return groove 5a of the deflector 5 is also performed at the same time, so that the ball groove can be formed more integrally and the ball 4 can be circulated. Will be performed more smoothly.
[0032]
Further, since the amount of secondary chamfering is temporarily chamfered prior to the secondary chamfering, the amount of the chamfering is the minimum necessary, and the chamfering work can be efficiently performed as a whole.
[0033]
Further, since the deflector 5 is fixed to the window portion 3c of the nut screw 3 by caulking, the coupling force of the deflector 5 to the nut screw 3 can be increased by simple means. Further, the displacement of the return groove 5a of the deflector 5 can be prevented, and the deformation of the ball groove formed by being integrally and smoothly connected can be surely prevented.
[0034]
The ball screw 1 in the present embodiment can be suitably used as a screw transmission device that transmits a steering assist force output from an electric motor to a steering shaft in an electric power steering device.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a ball screw.
FIG. 2 is a cross-sectional view of the nut screw of FIG. 1 removed.
FIG. 3 is a partial enlarged view of FIG. 2 showing a state where a ball travels.
FIG. 4 is a longitudinal sectional view with the deflector removed in FIG. 2;
5 is a cross-sectional view taken along line VV in FIG. 3. FIG.
FIG. 6 is a plan view of a deflector.
FIG. 7 is a front view of the same.
FIG. 8 is a bottom view of the same.
9 is a cross-sectional view taken along line IX-IX in FIG.
FIG. 10 is a right side view of FIG.
FIG. 11 shows a state in which primary chamfering is performed on the same part by the chamfering method of the deflector built-in window portion of the nut screw according to one embodiment of the invention described in claims 1 to 5 of the present application; FIG.
FIG. 12 is a view showing a primary chamfering state of a window incorporating a deflector of a nut screw.
13 is a cross-sectional view taken along the line XIII-XIII in FIG. 12, showing another primary chamfering situation.
14 is a view showing a secondary chamfering state after the deflector is incorporated into the deflector incorporating window portion of the nut screw, and is a cross-sectional view cut at the same position as FIG. 5. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ball screw, 2 ... Shaft screw, 2a ... Screw groove, 2b ... Screw thread, 3 ... Nut screw, 3a ... Screw groove, 3b ... Screw thread, 3c ... Deflector built-in window part, 3d ... Step part, 3e ... Screw Groove bottom, 3cf, 3cr ... window opening edge, 4 ... ball (steel ball), 5 ... deflector, 5a ... return groove, 5b ... substrate part, 5c ... leg part, 5d ... ridge, 5e ... suitable place (caulking) ) 5af, 5ar ... groove opening edge, 6-1 to 6-4 ... endless circuit, 10 ... chamfering device, 11 ... grindstone.

Claims (2)

The chamfering method for the nut screw deflector built-in window is
Before installing the deflector in the nut screw window, a primary chamfer that leaves a predetermined amount from the position corresponding to the opening edge of the groove of the deflector when the deflector is installed in the nut screw window,
A method of chamfering a window part with a built-in deflector of a nut screw, comprising: a secondary chamfer for removing a remaining amount part after the deflector is incorporated into a window part of the nut screw.   2. The method of chamfering a deflector built-in window portion of a nut screw according to claim 1, wherein the chamfering of the opening edge portion of the groove portion of the deflector is simultaneously performed during the secondary chamfering.

Images