JPS58113654A - Ball-and-screw unit with ball bearing - Google Patents

Abstract

PURPOSE:To reduce the overall diameter of a ball-and-screw unit so that the unit is aimed at being compacted, by commonly utilizing the inner race of a ball bearing rotatably supporting a nut with respect to a stationary member, as the outer peripheral surface of the above-mentioned nut. CONSTITUTION:Inwardly directed ball grooves 13, 14 are formed in both sides of the outer peripheral surface of a nut 4, which serves as an inner race threadedly engaged with a screw shaft 2, while an outer race is of split type. Outwardly directed ball grooves 17, 18 are formed in the inner peripheral surfaces of each pair of annular outer races 15, 16, corresponding to the ball grooves 13, 14 at the above-mentioned nut side. One outer race 16 is formed with a securing means fixed to a frame of a table or the like, or a securing flange 19 having mounting holes H.

Description

Detailed Description of the Invention The present invention is an inner ring for a pole bearing in which a steel ball is inserted between a screw shaft and a nut to enable relative rotational movement or axial movement, and the nut is installed on the outer periphery of the nut. This invention relates to an I-rule screw with a dual-purpose I-ru bearing.

Traditionally, feeding devices for cutting tools and worktables have a series of steel balls interposed between the screw shaft and the thread groove of the nut, allowing the steel balls to move freely. Instead of the t, which performs a feeding operation, a pole screw is provided in which rollers can perform a very light feeding operation using friction.

However, with such screws.

After the steel ball rotates once or three times in the thread groove of the screw shaft and nut, it is scooped up into the pole tube, which has a smaller radius of curvature than the nut, and rotates around the outside of the nut approximately once.
Because the steel ball is structured to return to its original position after turning around, the smooth movement of the steel ball rolling inside the pole tube is hindered, and this prevents the smooth movement of the nut or screw shaft.
This not only made high-speed movement impossible, but also caused noise problems.

In addition, in such conventional pole screws, dust is drawn into the interior from the nut end side through the screw tlII of the screw shaft, and the dust prevents the smooth rotation of the steel ball, making the relative movement of the screw shaft and nut heavy. There was a problem.

In addition, with conventional ball screws, there is backlash (axial clearance) in the steel balls that are fitted between the thread grooves of the screw shaft and nut, so either the screw shaft or the nut moves in the axial direction. When doing so, there are problems in that para-clash between the steel ball and the screw groove causes uneven wear and noise, and the responsiveness of the screw shaft or nut is poor. To counter this, countermeasures have been proposed, such as inserting a spacer to apply preload (preliminary compression) between the left and right nuts, and forcibly shifting the nuts in the compression direction or expansion direction to eliminate backlash. However, since unnecessary stress is applied to the nut, it is necessary to provide sufficient mechanical reinforcement, and there are problems such as the time-consuming press-fitting operation becomes inefficient in one assembly.

Furthermore, in the male screw, in addition to the relative rotation or axial movement of the screw shaft or the nut, in particular, the screw shaft and the nut can be freely rotated with respect to a fixed member such as a frame or a housing that supports the nut. It may be necessary to support the In such a case, a pair leader with a steel ball interposed between the inner ring and the outer ring is interposed between the fixing member and the nut. However, by installing the handle & loop pairing, the outer diameter of the overall screw increases, making it unsuitable for applications such as transmission devices that require precision and miniaturization. .

The present invention has been made in view of these conventional problems, and an object of the present invention is to scoop up a steel ball that has been transferred to a screw W# formed on a screw shaft, and then to use it again. By removing the tube on the outer periphery of the nut that returns to the thread groove, smooth and high-speed movement of the threaded shaft or nut is enabled, and the problem of noise when the steel balls return is eliminated.

In addition, another purpose is to provide a difference in the thread groove pitch of a single nut fitted on a screw shaft.
The purpose of the present invention is to apply preload (preliminary compression) to the steel ball with a single nut, omit a preload applying member such as a spacer, and thereby reduce the number of used parts and reduce costs.

Another object of the present invention is to prevent fan dust from entering the inside of the nut by integrally providing a wiper on the nut mounted on the screw shaft.

Furthermore, another object of the present invention is that the sol bearing, which is supported so as to be able to rotate once with respect to the fixed member, can be rotated freely by the inner ring, which is a component thereof, by using the nut as its component, so that the entire thread can be rotated by %. The aim is to make the outer diameter smaller and more compact.

The first gist of the present invention having the above-mentioned objects is to provide a screw shaft having a spiral thread formed thereon, a nut having a spiral thread groove tube formed on the inner periphery corresponding to an m-thread thread, and @ Mukuro Nut. a deflector that is embedded in the inner periphery of the screw thread and communicates between both thread grooves extending across the thread; and a deflector that is inserted between the corresponding thread grooves of the screw shaft and the nut to transfer between the screw shaft and the nut. A Gale screw with a ring and a ring is composed of a plurality of steel balls and a ring bearing with a goal interposed on the outer circumferential surface of the 111 nut.

The second aspect of the present invention is a screw shaft formed with a helical thread i#If, a nut formed with a helical thread #It corresponding to the ffa screwdriver on the inner periphery, and the nut. A deflector that is drilled around the circumference and connects both screw grooves that touch FIi4 across the screw thread, and a deflector that is fitted between the corresponding screw grooves of the screw shaft and the nut and rolls between the screw shaft and the nut. a plurality of steel balls and an outer ring with a mail interposed on the outer peripheral surface of the nut;
A ball screw with a sol bearing, characterized in that the wiper is attached to the VI4 end of the 111th century nut, and has a wiper formed on its inner periphery with a screw thread that engages with the screw thread of the screw shaft. .

The present invention will be explained below based on the illustrated embodiments. In FIGS. 1 to 6, 1 indicates the entire sol screw;
2 is a screw shaft having a spiral thread groove 3 formed at a certain pitch on the outer periphery of the shaft; 4 is a cylinder that is screwed onto the screw shaft 2 through a steel ball 5t and is movable in the axial direction or rotational direction; This nut 11] has a helical screw *6 with one ball 5 rolling on the inner circumference of the nut 4.
is provided, and the helical screw @6 corresponds to the screw thread 3 on the screw shaft side.

Here, the thread length 6 of the nut 4 is a male thread P between the thread @6°6 on the center side of the nut, as shown in FIG.
t, Pt (assuming the condition Pt = Pg) is the pitch Pa, Pa (Pi
``Suppose there is a condition of PI) greater than R, Pt
-Pcrow+α and Pt, Pg=P4+α. Therefore, the load steel ball 51 located on the left side of the nut 4 center shaft is preloaded to the left, while the load steel ball 5t located on the fabric side is preloaded to the right, respectively, in the axial direction outward of the nut 4. become. In addition, contrary to the pitch Ps - PI f, the pitch Ps on both sides is smaller than PI L, PI, P, = P, -α and R, P
By establishing the relationship I = PI-a, the loaded steel ball 51 on the left side and the sentient loaded hard ball 5! 412) can be preloaded in the axially inward compression direction.

7.8 is an elliptical through hole bored in the top and bottom of the inner periphery of the nut 4 so as to be offset in the axial direction, and the through hole 7.8 is Screw 11116ff formed continuously in a spiral shape with O pitch metal provided on the inner periphery of the nut
It is installed across the i. 9 is # Ki Natsuto's through hole 7
．． As shown in FIG.
The deflector 9 is a cylindrical body with an outer peripheral shape M that matches the shape of the through hole 7.8, has a curved bottom 9, and forms nine recesses 9b, near the ends of both walls 9c, 9c. A semicircular inlet 9d and an outlet 9e are provided which are offset in the longitudinal direction. Therefore, the curved bottom surfaces of the inlet 9d and the outlet 09@ coincide with the curved bottom surfaces of the screws #l 6+ and 62 at the same height, and the steel ball 5 flows into the recess 9b of the deflector or is recessed. When steel ball 5 flows out from inside 9b, is the transfer of #1 ball a circle? We guarantee that it can be performed in V. Incidentally, recess 9
The depth b can be set freely as long as the steel ball 5 does not come into contact with the thread of the screw shaft 21ill and prevent smooth movement of the ball when the steel ball 5 passes through the deflector 9. can be established.

Next, as shown in FIGS. 4 and 5, the deflector 9
is the war-starting position of the steel ball 5 when the steel ball 5 crosses the thread M formed between the adjacent screws flj 6r and 6 and makes one round through each of the threads continuous in a spiral manner. The tip of the position (e.g. 20° position) and @lfrM1
111 position B, that is, hand III at the 3600 position (for example, the 3400 position), connects adjacent screws #6t-6m. The movement of the steel ball 5 transferring in the east thread groove 61 e 62 at cC will be explained with reference to FIGS. 5, when the inner pipe of the nut goes around the middle, it moves to the thread groove atll on the outer side of the adjacent nut,
Eventually, the rolling end position B is reached. Then, from the mosquito rolling end point tB, avoid contact with the thread on the screw shaft 2 side, take a slight detour outward in the rearward direction of the nut's central axis - Cross the thread between Mt and return the nut to the original thread groove 6 of the inner joint! Return to the transfer start position set in . The bales are moved in a single thread through the threaded screw 61 in the same cycle as the above-mentioned operation.

In the example shown in 1, two deflectors having the above structure are installed at the top and bottom of the inner circumference of the nut 4, but three, four, etc. may be installed as necessary. In either case, they are arranged at equal intervals in the circumferential direction so as to equally divide the circumference.

10.11 has its outer circumference integrally attached to the inner circumferential surface of both ends of the nut 4, and the thread groove 3 of the screw shaft 2- is attached to the inner circumference of the opposite side.
A screw thread Nf that fits all around the inside of the nut 4 is an annular wiper formed therein, and these wipers /4'-10 and 11 are used to isolate the internal space of the nut 4 from external sounds.

Reference numeral 12 is attached to the outer circumferential surface of the nut 4 screwed onto the screw shaft 2, and is a screw bearing 7'. In the present invention, the inner ring of the goal bearing also serves as a male screw nut.The goal bearing according to the present invention will be described in detail below with reference to the drawings. On both sides of the outer circumferential surface of the nut 4, inward facing rings are provided, while the outer ring is shaped like a split tie.
On the inner peripheral surface of a pair of O1l-shaped outer rings 18 and 160, there is an outer ring O#-rule length 1 corresponding to the nut side 11-ru length 13.14.
7.1g is formed. And a pair of outer rings 1! S,
By inserting a spacer St on the two sides that presses each outer ring of the scissors in the direction of the torn skin in the middle of the 16, a gap between each outer ring side and the nut side is inserted. It is possible to apply a preload t in the expansion direction (the direction in which the goals move Km apart from each other) to the I-le inserted into the spacer, and this preload adjustment is performed by adjusting the thickness of the spacer S.

One ring 16 of the outer ring is provided with a fixing means for fixing it to a frame such as a work table, that is, a fixing ring 19 having a mounting hole M1, and a nut used as the inner ring of the one ring bearing. A gear 20 for transmitting rotational torque to the cough nut from an external drive means is formed on the outer periphery of one end of the cough nut. Of course, as a member for transmitting rotational torque to this inner ring nut, there is no need to heat it up, and even if you use other transmission means, such as a timing belt (not shown), which is rumored to be more effective than hu. Does the present invention have a single bearing, depending on the configuration? - Operation of the screw t#I9am Based on the usage statement ml1lI, two parallel rows of track G on the fixed side grate P.
t-installed, and the work table 21e is mounted on the scissor track G.
) A fixed linear sliding bearing 22 is placed on the bottom surface so that the scissors work table 21 can freely move in the axial direction on the track G.

On the other hand, on the supporting stand 23 erected on the fixed root P, the 7 flange 19 for fixing the outer ring 16 on the blade side is r*tyed by screwing the bolt into the sealing hole H. -1 pair/g12
Outer rings 15 and 16 are fixed in either the axial direction or rotational direction, while the role of the inner ring is fixed in the axial direction and movable in the rotational direction. (1) In this state, if (9) rotational torque is transmitted from an external driving means, for example, the stepping motor 24 to the nut 4 via the gear 20, then l*
The nut rotates in the forward or reverse direction and feeds the screw shaft 2, which is supported in a fixed state on the axially expanding shaft, through the workpiece 21 and the platen (25tP). The screw shaft 2Ifi performs a relative vertical movement to the left or right in the drawing. As a result, the screw shaft 2f: the fixedly held work table 21 moves in the axial direction together with the screw shaft 2, which rotates 11 times in the axial direction with respect to the nut 4.
lclkru.

1110 to 1112 show another embodiment of the screw with a bearing according to the present invention, and in this second embodiment, the annular screw on the blade side is
M is attached to a cylindrical $-shaped nut 4 through a fitting 26.
The one rule cy>JII shape wire Δ-11m fixed to the outer end surface of the nut 4 and the other fixed to the inner periphery of the nut 4 is connected by the gear body 27 fixed to the other outer end surface of the nut 4 by the I bolt. The nut 4 is held in place to enhance the fixation of the nut 4 to the wipers 10a and 10a. Ball bearing 12
The outer peripheral surface of the cylindrical nut 4, which serves as the inner ring of the nut 4, has enlarged goal grooves 13a facing outward, opposite to those in the embodiment.

14m is provided, and for this split TIG OS
The inner peripheral surfaces of the shaped outer rings 15m and 16m have inward grooves 17a corresponding to the goal grooves 13m and 14a on the nut side.
, 18m are formed.

An annular spacer S on two sides is fitted in the middle of the pair of outer rings 15m and 16m to form each outer ring 15a.

16at - by pulling towards each other,
On each outer ring side and nut side? - It is possible to apply a preload in the compression direction (direction in which the sol approaches each other) to the goal inserted between the sol grooves. Regarding other configurations of this second embodiment,
Since the configuration is the same as that of the first embodiment, the same reference numerals as those of the first embodiment are given and the explanation fIA is omitted.

The present invention has the above-described structure and operation, and in the male screw of the present invention, preload can be applied to even one nut by simply making a difference in the pitch of the thread vibration on the nut side, and therefore, it is possible to apply preload to a single nut. There is no need to use such a preload applying member. In addition, there is no need to use a multi-soup, which scoops up the hard balls that have rolled and moved through the thread groove formed on the screw shaft, makes them go around the outside of the nut, and then returns to the thread groove again. The smooth and high-speed movement of the nut can be guaranteed, and the noise generated when the steel balls return can be completely prevented.

In addition, in the single screw according to the present invention, by integrally providing the wire screw on the nut fixed on the screw shaft, it is possible to ensure smooth alignment and circulation of the steel balls while preventing dust from entering the inside of the nut. Since intrusion is completely prevented, accurate relative movement between the screw shaft and nut can be guaranteed over a long period of time.

Furthermore, since the goal screw of the present invention adopts the through-through preload (pre-compression) structure described above, the backlash (axial clearance) is zero, so it can be inserted between the screw shaft and the thread groove of the nut. There is no axial play in the steel ball and therefore during axial movement? - Excellent response to screw movement.

Furthermore, there is no play when changing the feed direction when moving in the axial direction, so followability is good. Further, since the single screw having a preloaded structure has high rigidity, accurate positioning is possible, and wear does not occur, making it durable for long-term use.

Further, in the present invention, the conventional tube that serves as the return means for the steel balls is removed from the outer periphery of the nut, and
Nuts for fixed parts such as work tables? The goal bearing, which is rotatably supported, can be used for both the inner ring and the nut, which are its constituent members. Therefore, the outer diameter of the entire male screw can be kept small, and the space occupied during installation is limited. The effect is that the lens can be effectively applied to the device, which is beneficial in practical use.

Furthermore, by adopting a preload structure in the goal bearing of the present invention, the rigidity of the balls interposed between the outer ring and the inner ring is constant, so there is no wear, and therefore it is suitable for long-term use. It has incredible effects, such as gaining benefits.

[Brief explanation of the drawing]

The drawings show an embodiment of a ball screw with a pole bearing according to the present invention, and FIG. 1 is a side view of the same, and FIG.
Fig. 3 is a vertical cross-sectional front view of the nut, Fig. 3 is a cross-sectional bottom view of WX1 showing the pitch of the thread groove on the nut side, and Fig. 4 is a steel ball rolling on the inner surface of the nut with the screw shaft removed. moving state eat
G1 Figure IV - ff - cross-sectional bottom view, ms figure is a perspective view of the main part of the deflector installation part on the inner circumference of the nut, projected on a plane,
Fig. 6 is an explanatory diagram showing the structure of the deflector, Figs. 7 and 8 are explanatory diagrams showing the locus of the steel ball rolling between the thread groove between the screw shaft and the nut, and Fig. 9 is an explanatory diagram showing the trajectory of the steel ball rolling between the thread grooves between the screw shaft and the nut. ? 1110 is a longitudinal sectional front view showing the use condition m' of the screw.
Other examples of screws with bearings are shown.
iaA, III 1 Figure Hgl O Figure Xl-X1i! FIG. 10 is a longitudinal sectional front view and FIG. 10 is a cross-sectional bottom view showing a state in which the steel balls roll on the inner circumferential upper surface of the nut with the screw shaft removed. Explanation of symbols l...I-le screw 2...Screw shaft 3, 6
,6. ．． 6. ...Thread groove 4...Nut 5.5, 5
．． ... Steel balls 7, 8 ... Through hole 9 ... Deflector - 9 & ... Bottom 9b ... Recess 9C ... Side wall 9d ...
Entrance 9e...Exit 10, 10a,
11, 11 a-...wiper 12.12m...
Gear bearing 13.13m, 14.14a, 17.18 = & wheel groove 1
5.15m, 16.16m... Outer ring 19... 7 lunges for one foot 20... Gear 21... Work table 22... [fll sliding bearing 23... Support stand 24... Stepping motor 25...Bracket 26...Mounting tool 2
7... Gear body A... Transfer start position B... Transfer end position H.
...Mounting holes M, N...Thread 0...Central axis 11i P, Ps, Ps, P4
...Pitch S...Maza patent applicant Hiroshi Teramachi Figure 5 1117 Figure 8 Figure 1O x 1''

Claims (1)

[Claims] (1) A screw shaft formed with a III spiral O screw St-,
a nut having a spiral thread groove corresponding to the thread groove formed on the inner periphery; a deflector formed on the inner periphery of the nut and communicating between both adjacent thread grooves across the thread;
* A plurality of steel balls are fitted between both screw grooves corresponding to the screw shaft and the nut, and an outer ring is provided with a mail interposed on the outer surface of the screw shaft and the nut. A ball screw with a single pole bearing and a tube featuring a single pole bearing. (The nut described in Section I11 has a pitch difference in the spiral threads formed on its inner periphery. A single screw with a single bearing. (4) The double bearing described in item 3 is provided with a fixed foot flange having a mounting hole on the outer ring on the blade side. thing'
Is it a feature? -L screw with -L bearing. (5) Form a spiral thread groove on the next screw shaft and inner part.
a nut formed on a spiral thread groove corresponding to the thread groove marked r; a deflector drilled on the inner periphery of the drawing nut and communicating with both adjacent thread grooves across the thread; and the screw shaft and the nut. a plurality of rigid balls that are fitted between corresponding thread grooves of the nut and roll between the screw shaft and the nut; a rigid galle bearing having an outer ring with a ring interposed on the outer circumferential surface of the nut; A tail screw with a single bearing, characterized in that it is integrally attached to both ends of a nut and has a wiper formed on its inner periphery with a screw thread that engages with a thread groove of a #-marked screw shaft. (6) The nut described in No. 5tIL is a single screw with a pool bearing, which has a pitch difference in the helical thread formed on its inner periphery. (n) The nut described in item 816 has one end 11 of the nut.
It is characterized in that it is integrally equipped with a transmission member.
A screw with a double bearing. <8) The goal bearing described in item 187 is equipped with a goal bearing characterized in that the outer flange is provided with 7 fixing flange having a hole with an IIL. - Le screw.