JPH04129957U - feed screw device - Google Patents

Abstract

(57) [Summary] [Purpose] To enable high-speed feeding without producing large noise in a feed screw device consisting of a screw shaft and a nut member screwed onto the screw shaft. [Structure] A support frame 22 is provided with an insertion hole 18 into which a screw shaft 12 having a thread groove 16 on the outer periphery is inserted, an inner ring 42 fixed to the support frame 22, and a plurality of balls 46 connected to the inner ring 42. The nut member 14 is composed of a plurality of bearings 30 disposed around the insertion hole 18 and has an outer ring 44 that can rotate relative to each other. brought into contact. Further, the axial center of the bearing 30 is inclined with respect to the axial center of the screw shaft 12 by the same angle as the lead angle of the thread groove 16.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

The present invention relates to a feed screw device, and particularly to a feed screw device for screwing a nut member onto a screw shaft. It concerns structural improvements.

0002

[Conventional technology]

A screw shaft with a thread groove on the outer periphery and a nut member that is screwed onto the screw shaft. and either the screw shaft or the nut member cannot rotate around the shaft. By rotating the other in the state, the screw shaft and nut member are mutually A feed screw device that relatively moves in the axial direction has been widely known. Such shipping In a screw screw device, the screwing means on the nut member side with respect to the thread groove of the screw shaft is screwed. There are two types: those that make sliding contact with the groove and those that make rolling contact. slippery Examples of contact types include, for example, a combination of normal male and female threads. A slide screw with a threaded connection or a string made of special resin is inserted along the thread groove. There are string screws etc. They have a simple structure and can be easily configured. , low price. On the other hand, there are rolling contact types, such as rolling elements. A large number of steel balls are installed around the thread groove, and these steel balls move inside the nut member. Ball screws that are configured to allow circulation or that are continuous in the axial direction with multiple thread grooves. Multiple small-diameter rollers with many ridges that roll into contact with each other are arranged around the axis. There are roller screws, etc. These have extremely low frictional resistance and are said to have high mechanical efficiency. It is also easy to ensure relatively high accuracy.

0003 By the way, in recent years, as work speeds have increased, it has become difficult to maintain feeding accuracy in feeding devices. There is an increasing demand for high-speed feeding. In contrast, the former's sliding contact In addition to having relatively low accuracy, the type has high frictional resistance and is mechanically ineffective. Due to the low rate, there was a limit to high-speed feed. Therefore, as a high-speed feeder, It is appropriate to use the latter type of rolling contact.

0004

[Problem that the idea aims to solve]

However, in the ball screw, the distance between the steel balls is not regulated in any way. Because they are arranged without any Frequent collisions and loud noise occur when entering and exiting the ring path (ball return tube). There was a problem with the generation of sound. Furthermore, the roller screw has a complex structure. It is complicated and expensive, and the lead that multiplies the feed rate is relatively small, making it difficult to respond to high speeds. There was a problem that the efficiency was low.

[0005] This invention was developed against the background of the above circumstances, and its purpose is to: To provide a feed screw device capable of high-speed feeding without producing large noise. It is in.

[0006]

[Means to solve the problem]

In order to achieve this purpose, the gist of the present invention is to provide a screw groove on the outer periphery. A screw shaft is provided, and a nut member is screwed onto the screw shaft. When either the shaft or nut member cannot rotate around the shaft, rotate the other. By driving, the screw shaft and nut member are moved relative to each other in the axial direction. In the feed screw device for moving the nut member, (a) the screw shaft is inserted through the nut member. (b) a support frame provided with an insertion hole in which the support frame is fixed; The inner ring is rotatable relative to the inner ring via rolling elements, and the outer periphery is rotatable relative to the inner ring via rolling elements. and an outer ring whose portion is brought into rolling contact with the thread groove, and is arranged around the insertion hole. The reason lies in that the structure includes a plurality of bearings provided therein. Note that the bearing preferably has an axial center that is aligned with the axial center of the screw shaft. It is arranged on the support frame in an attitude inclined by the same angle as the lead angle of the groove. Further, the thread groove preferably has an arcuate cross-sectional shape. , the outer ring has a convex arc-shaped outer peripheral surface corresponding to the cross-sectional shape of the thread groove. The ring member obtained is then attached. Further, the nut member preferably includes the support frame on which the plurality of bearings are disposed. The frame includes a pair of frames, and the pair of support frames are respectively arranged. The outer rings of the bearings are pressed against the wall surface on the opposite side of the thread groove, and the spacer It is integrally configured through.

[0007]

[Effects of action and invention]

In the above feed screw device, the nut member is an inner ring fixed to the support frame. is provided so that it can rotate relative to the inner ring via rolling elements, and the outer periphery is threaded. It has an outer ring that rolls into contact with the thread groove of the shaft, and is attached around the insertion hole of the support frame. Since it is equipped with multiple bearings arranged in A good rolling contact condition is obtained, resulting in high mechanical efficiency and high-speed feed. Even when this happens, large noises caused by collisions etc. are not generated. Also It is possible to easily construct the nut member using commercially available products such as ball bearings. In this case, the nut member can be constructed at low cost, and even if it breaks, Easy to replace. Furthermore, if you use a bearing with a seal or shield, This eliminates the need for troublesome maintenance such as refueling.

[0008] Also, the axial center of the bearing is inclined at the same angle as the lead angle of the thread groove with respect to the axial center of the screw shaft. When the bearing is installed on the support frame in an inclined position, the thread groove of the screw shaft Since the and the rolling direction of the bearing are parallel to each other, slipping may occur between the thread groove and the outer ring. The outer ring can now rotate smoothly, further improving machine efficiency. In addition, wear at those contact points is reduced and the life of the device is increased.

[0009] In addition, for a thread groove whose cross-sectional shape is an arc, the outer ring of the bearing is A ring member with a convex arc-shaped outer peripheral surface corresponding to the cross-sectional shape is attached. In this case, the contact area between the thread groove and the outer ring increases, so the The surface pressure on the contact area is reduced, making it possible to withstand high thrust loads. Wear is reduced and equipment life is increased.

0010 Further, the nut member includes a pair of support frames, and the pair of support frames The outer rings of the bearings disposed on each arm are pressed against the wall surface on the opposite side of the thread groove. If the unit is integrated with a spacer under pressure, the axial Since the gap in the direction is zero and there is no backlash, high positioning accuracy can be achieved. can.

[0011]

【Example】

Hereinafter, one embodiment of the present invention will be described in detail based on the drawings.

0012 1 and 2 are a front view and a front view of a feed screw device 10 which is an embodiment of the present invention. FIG. The feed screw device 10 includes a screw shaft 12 and its The nut member 14 is screwed onto the screw shaft 12 via a screwing means. 2, with the nut member 14 unable to rotate around the shaft. By rotating the nut member 14 counterclockwise or clockwise, the nut member 14 is rotated against the screw shaft. 12 in the axial direction, that is, in the left direction or right direction in FIG. It is something that

[0013] The screw shaft 12 has thread grooves 16a, 16 formed on its outer periphery in a right-handed four-start thread. b, 16c, 16d and connected at its own terminal. It is designed to be rotationally driven by a drive device that does not operate. For this reason, screw shaft 1 Lead 2 is large and suitable for high-speed feeding. In addition, in FIG. 2, the screw shaft 12 The cross section of is cut out at four different positions along each of the four thread grooves, and is the same as above. Each portion of the thread grooves 16a, 16b, 16c, and 16d is partially shown. The cross-sectional shape of each of the thread grooves 16a, 16b, 16c, and 16d is It has a concave approximately semicircular arc shape, and each section is shown in Figure 1 for ease of understanding. The valley line at the center of the surface is shown as a solid line. The screw shaft 12 is similar to a normal ball screw shaft. It has been hardened and has sufficient surface hardness and wear resistance. Na In the following explanation, the four thread grooves 16a, 16b, 16c, and 16d will be particularly distinguished. Unless otherwise specified, they will be collectively referred to as the thread groove 16.

[0014] On the other hand, the nut member 14 has an insertion hole 18 in the center through which the screw shaft 12 passes. A fastening hole 20 is provided on the outer periphery for attaching other machine elements to be moved linearly together. A flange-shaped support frame 22 provided at four locations on the side and a support frame 22 provided at four locations around the insertion hole 18. Four bearing units 24a, 24b arranged at four equally spaced locations in the circumferential direction , 24c, 24d, and these four bearing units 24a, 24 b, 24c, and 24d are the four thread grooves 16a, 16b, 16c, and 16d. They are positioned at predetermined positions where they can be engaged with each other.

[0015] The bearing units 24a, 24b, 24c, and 24d are made of the same parts. A support block 28 is configured as shown in FIG. , a bearing 30 having a width dimension smaller than the groove width of the thread groove 16, and a pair of spaces. The bearings 30 and spacers 32, 34 are attached to the support block 28. bolts 36 for attaching to the support frame 22 and the support block 28 to the support frame 22. It consists of a pair of bolts 38 and 40 for fixing. Bearing 30 etc. are installed The inclination angle of the mounting surface 26 is made to match the lead angle of the thread groove 16, and the bearing 3 A posture in which the axial center of screw shaft 12 is inclined by the same angle as the above lead angle with respect to the axial center of screw shaft 12. It can be installed with. Below, bearing units 24a, 24b, 24 In cases where there is no particular distinction between c and 24d, they are collectively referred to as bearing unit 2. Say 4.

[0016] A cross section perpendicular to the thread groove 16a at the position of one bearing unit 24a (see FIG. As shown in FIG. A spacer 32 is inserted and a spacer 34 is inserted on the head side of the bolt 36. The screws can be tightened by adjusting the thickness of the spacer 32. The positioning in the thread pitch direction is finely adjusted so that the bearing 30 is located in the center of the groove 16a. be done. The bearing 30 is a commercially available deep groove ball bearing, and has an inner ring 42 and an outer ring. 44, and a large number of balls 46 inserted between them. Inside The inner diameter of the ring 42 fits with the outer diameter of the lower neck portion 50 of the bolt 36 with an interference fit. The inner ring 42 is attached to the support block 28 without rattling. is fixed to the support frame 22. The outer ring 44 is connected to the inner ring 42 via balls 46. A pair of outer circumferential angle R portions 52, 5 on the outer circumferential side 4 are adapted to substantially contact the left and right wall surfaces of the thread groove 16a. child The same applies to the other bearing units 24b, 24c, and 24d, and all The gap between the outer ring 44 and the thread groove 16 in the axial direction of the threaded shaft 12 in the bearing 30 of is approximately zero, ensuring the same level of positioning accuracy as conventional ball screws. Ru. In addition, lubrication at the contact area between the outer ring 44 and the thread groove 16 is achieved by forming a thin oil film. Sufficient lubrication can be achieved with just a small amount of lubricant, and lubrication frequency is extremely low. It is good to have very little. Note that the bearing 30 is equipped with a seal and is attached to the outer ring 44 side. A seal 48 that covers the gap with the inner ring 42 prevents leakage of lubricant that lubricates the balls 46. It is attached to the bearing 30 in advance for the purpose of preventing foreign matter from entering from outside. Moreover, the mutual spacing between the many balls 46 is regulated by a cage (not shown), They are kept from colliding with each other.

[0017] In the feed screw device 10 configured as described above, the rotatably supported One end of the screw shaft 12 is connected to a drive device (not shown), and a nut member 14 Other mechanical elements are attached to the nut member 1 through the fastening hole 20, etc. 4 is in a state where it cannot rotate around the axial center of the screw shaft 12 and can move in the axial direction. In this case, when the screw shaft 12 is rotated counterclockwise in FIG. Four bearing units 24a are engaged with 6a, 16b, 16c, and 16d. , 24b, 24c, and 24d are the outer peripheral angle R of the outer ring 44 in each bearing 30. Since the portion 54 rolls into contact with the right wall surface of the screw groove 16 while being pressed, the screw shaft 12 to the left in FIG. 1, the nut member 14 and other mechanical elements The entire object is fed and moved to the left. Conversely, the screw shaft 12 is rotated clockwise. Then, each bearing unit 24 has an outer peripheral angle R of the outer ring 44 of each bearing 30. Since the portion 52 rolls into contact with the left wall surface of the thread groove 16 while being pressed, the thread shaft 12 to the right in FIG. 1, and the nut member 14 etc. are fed to the right be moved.

[0018] In this way, in the feed screw device 10 of this embodiment, the The threading means of the cut member 14 is such that the inner ring 42 is connected to the support frame via the support block 28. 22, and the outer circumferential angle R portions 52, 54 of the outer ring 44 are fixed to the threaded shaft 12. Each bearing 30 is provided to roll into contact with the same groove 16, and around the insertion hole 18. It is composed of four bearing units 24a, 24b, 24c, and 24d arranged. Therefore, a good rolling contact condition between the bearing 30 and the thread groove 16 can be obtained. In addition to achieving high machine efficiency, it is also possible to perform high-speed feeding without using the conventional method. It does not generate large noise due to collisions of rolling elements, etc., and the contact area Good lubrication conditions can also be obtained with less frequent lubrication. Also, commercially available depth By using the ball bearing as it is as the bearing 30, the bearing unit 24 and further The nut member 14 can be constructed at a low cost, and the nut member 14 can be constructed without breaking. Even if it is damaged, it can be easily replaced. In addition, the bearing 30 includes a seal 48. Therefore, maintenance such as oil supply to the bearing 30 is not necessary.

[0019] Further, the bearing 30 has an axial center that is a lead of the threaded groove 16 relative to the axial center of the threaded shaft 12. Since it is arranged on the support frame 22 in an attitude tilted by the same angle as the corner, the screw The thread groove 16 of the shaft 12 and the rolling direction of the bearing 30 are parallel to each other, and the thread groove 16 and the outer ring are parallel to each other. The outer ring 44 can now be rotated smoothly without slipping between the outer ring 44 and the outer ring 44. This further improves mechanical efficiency and reduces wear at the contact points. Improved equipment life.

[0020] In addition, since the screw shaft 12 is a four thread screw, it is attached to the nut member 14 at equal angular intervals. The four bearings 30 provided have the same distance from the support frame 22, It is sufficient to use a common support block 28, and the number of types of parts is small, and the nut member 1 4 has the advantage of being simple and inexpensive.

[0021] Next, another embodiment of the present invention will be described. In addition, the parts common to the above-mentioned embodiments The same reference numerals will be given to the same reference numerals and the explanation will be omitted.

[0022] 4 and 5 show a front view and right side with a part of the feed screw device 60 cut away. A front view of each is shown. This feed screw device 60 includes a screw shaft 62 and a screw shaft 62. The nut member 64 is screwed into the nut member 64. The screw shaft 62 has its outer periphery is equipped with a thread groove 66 formed in a right-handed single thread, and the cross section of the thread groove 66 is The shape is approximately a semicircular arc concave toward the center of the shaft.

[0023] The nut member 64 in this embodiment includes a pair of support frames 68 and 70. The pair of support frames 68 and 70 allow the threaded shaft 62 to pass therethrough. 4 holes having insertion holes 72 and 74, respectively, and equally spaced in the circumferential direction. A bearing 76 is disposed in each. Also, between the support frames 68 and 70 The pins of the thread groove 66 are located at four locations on the outer circumferential side corresponding to the positions of the bearing 76. Each spacer 78 has a predetermined axial length determined in accordance with the The four sets of bolts 80 and nuts 82 are used to connect the two supports. Holding frames 68 and 70 are integrally constructed. Note that 84 is the support frame. This is a key for positioning the relative positions of the arms 68 and 70 around the axis.

[0024] Each bearing 76 at the four locations is attached to a bolt 8 along with a pair of spacers 85 and 87. 6 to support frames 68 and 70, respectively, and , a pedestal 88 of different sizes corresponding to the leads of the thread groove 66 is attached to a predetermined bearing 76 and a support. By being inserted between the holding frames 68 and 70, the thread groove 66 and the rolling They are each positioned at predetermined positions where they can be contacted. The bearing 76 is This part is a deep groove ball bearing equipped with a cage and a seal like the bearing 30. , an inner ring 42, an outer ring 44, and a large number of balls 46 inserted between them. , a ring member 90 is integrally fixed to the outer ring 44. Ring member 90 has a convex arc-shaped outer peripheral surface 92 corresponding to the cross-sectional shape of the thread groove 66. , is fitted onto the outer periphery of the outer ring 44 by press fitting etc. and fixed integrally, and the thread groove 6 It is designed so that it can be brought into contact with the inner wall surface of No. 6 with a large contact area. In addition, each of the above The shaft center of the bearing 76 is perpendicular to the support frames 68, 70, that is, the screw shaft It is attached in a position parallel to the axis of 62.

[0025] As mentioned above, the spacer 78 is interposed between the pair of support frames 68 and 70. Because it is inserted into the screw shaft 62 as shown in FIG. 66 and the axial dimension of the spacer 78, the support frame 68 and 70 and are in rolling contact with the thread grooves 66, respectively. Thrust forces in opposite directions in the axial direction of the screw shaft 62 are applied to the bearings 76. be made to use Therefore, each outer ring 44 is connected to the ring member 90 via the ring member 90. is pressed against the wall surface on the opposite side of the threaded groove 66. As a result, in the axial direction of the screw shaft 62, The gap between each bearing 76 and the thread groove 66 in the is designed to prevent this from occurring.

[0026] Here, the feed screw device 60 of this embodiment has a thread groove whose cross-sectional shape is an arc shape. 66, the outer ring 44 of the bearing 76 has a convex shape corresponding to the cross-sectional shape of the thread groove 66. Since the ring member 90 having an arc-shaped outer peripheral surface is attached, the thread groove 6 The contact area between 6 and the ring member 90 is increased, and the surface pressure at the contact portion is reduced. In addition to being able to withstand high thrust loads, wear on the contact parts is reduced. Equipment life is improved.

[0027] Further, the nut member 64 includes a pair of support frames 68 and 70, and , the pair of support frames 68 and 70 are integrally constructed with a spacer 78 in between. The ring members 90 of the bearings 76 disposed in each are located on the opposite side of the thread groove 66. Because it is pressed against the wall of High positioning accuracy can be obtained.

[0028] The nut member 100 shown in FIGS. 6 and 7 is used in the feed screw device 10 described above. This shows another aspect of the nut member 14, in which the support frame 102 is Compared to the holding frame 22, in addition to the disc-shaped flange portion 104, four sets of the bearings are included. 30 and a small diameter cylindrical portion 106 that holds a pair of spacers 32 and 34. ing. The small diameter cylindrical portion 106 has an inner peripheral surface 108 having the same diameter as the insertion hole 18. The screw shaft 12 is inserted through the screw shaft 12, and the screw shaft 12 is inserted at equal intervals in the circumferential direction. arcuate openings from the outer circumferential surface 110 to the inner circumferential surface 108 at four locations. It has four cut grooves 112. on a plane perpendicular to the axis of the screw shaft 12 The inclination angle of each groove portion 112 relative to the support block 28 is the same as that of the mounting surface 26 of the support block 28. , are made to match the lead angle of the thread groove 16. The bolt 36 is a small diameter cylindrical part. Pass through the insertion hole 116 at right angles to the groove 112 from the end surface 114 side of 106 and tighten. be included. As a result, the bearing supported by the bolt 36 in the groove 112 30 is inclined at the same angle as the lead angle of the thread groove 16 with respect to the axis of the threaded shaft 12. It can be installed in any position. Note that the external dimensions of the nut member 100 are similar to those of conventional balls. It is the same as that of a nut on a screw, and compatibility is taken into account.

[0029] In such a nut member 100, the number of parts is small, so delicate Positioning work between members is greatly reduced. In addition, the flange portion 104 and the small diameter cylinder The support frame 102 consisting of the section 106 has high rigidity, and the four bearings 3 By maintaining high positional accuracy of 0, positioning between parts that occurs with use is reduced. This has the advantage that rattling due to misalignment can be suppressed to a minimum.

[0030] The bearing 120 shown in FIG. 8 includes a radial needle bearing and a thrust needle bearing. This is an example in which the inner ring 12 has an integral flange portion 122. 4. An outer ring 128 having a semicircular arc-shaped outer peripheral surface 126 and having a ring member integrated therein; Radial needle 130 and thrust needle 132 as rolling elements , 134. If such a bearing 120 is used, a high load can be achieved. It becomes possible to construct a feed screw device that can withstand heavy loads.

[0031] The pedestal 140 shown in FIG. 9 supports the bearing 76 in the feed screw device 60 described above. The axis of the screw shaft 62 is inclined by the same angle as the lead angle of the screw groove 66. It is intended for installation in an inclined position, and the inclination angle matches the lead angle above. ramps 142 to be bolted to the support frames 68 and 70; It has become. By attaching the bearing 76 using such a pedestal 140, The ring member 90 can be rotated smoothly with respect to the thread groove 66. Mechanical efficiency is further improved, and the contact area is expanded to reduce wear at the contact area. This will be further reduced.

[0032] Although the embodiments of the present invention have been described above in detail based on the drawings, the present invention has other aspects. It can also be carried out.

[0033] For example, in the embodiment described above, the bearing 30 is a commercially available deep groove ball bearing. The receiver 120 has a radial needle bearing and a thrust needle bearing. Each combination was used as a bearing in the present invention, but the Other types of bearings as long as they can carry both radial and thrust loads , such as combination angular bearings, double row angular bearings, cross roller bearings, etc. A commercial product or a bearing member constructed by combining other rolling elements may be used.

[0034] In addition, in the above-mentioned embodiment, the insertion in the support frames 22, 68, 70 Bearings 30 and 76 were installed at four locations around holes 18, 72, and 74. , the number of bearings 30, 76 can be changed as appropriate. Also, screw The shaft 12 is provided with four thread grooves 16a, 16b, 16c, and 16d, and the threaded shaft 6 2 was provided with one thread groove 66, but the number of thread grooves may be changed as appropriate. A feed screw device can be configured with various leads by arranging the bearings accordingly. It is possible to do so.

[0035] Further, the bearings 30 and 76 in the above embodiment are equipped with a seal 48. However, there is no problem even if a bearing without seal 48 or shield is adopted. . Also, a pair of spacers 32, 34 and 85, 8 are provided on both sides of the bearings 30 and 76. 7 were provided, but these spacers are not necessarily essential.

[0036] In addition, in the embodiment shown in FIG. 16, the outer ring 44 of the bearing 30 is brought into rolling contact with the outer ring 44 of the bearing 30, but the cross-sectional shape is in rolling contact with a thread groove with a cross-sectional shape other than an arc shape, such as a trapezoidal thread. This may be the case.

[0037] Furthermore, in the embodiment of FIG. 4 described above, a spacer having a predetermined axial length is used. 78 was inserted between the pair of support frames 68 and 70, but instead of this, , a compression coil spring, a bellows spring washer, or multiple shims can be used as a spacer. There is no problem even if it is used as such. In addition, a spacer is inserted between the pair of support frames. Alternatively, for example between the bearing 76 and the spacer 85 and/or the bearing 7 By inserting a wave washer etc. between 6 and spacer 87, both sides can be supported. The ring member 90 of the bearing 76 in the frames 68 and 70 is opposite the thread groove 66. It is also possible to configure it so that it is pressed against each side wall surface. In that case , a pair of support frames is not necessarily required; one support frame can be used to support both. It is also possible to arrange a bearing on only one surface or one surface.

[0038] In addition, in the embodiment shown in FIG. was parallel to the center, but within a plane that includes the axial center of the screw shaft 62 and the axial center of the bearing 76. The axis of the bearing 76 may be tilted, for example, when the nut member 64 is moved. When the thrust load differs depending on the direction of movement, the movement is subject to a large thrust load. The axial center of the bearing 76 is inclined so that the axial center of the bearing 76 approaches the axial center of the screw shaft 62 as it advances in the moving direction. If the bearing 76 itself is left open, it is possible to reduce the thrust load that the bearing 76 itself receives. . This also applies to the nut member 14.

[0039] Further, in the above embodiment, the nut members 14, 64 cannot rotate around the shaft. As a result, the nut members 14, 64 are rotated by rotating the screw shafts 12, 62. However, the screw shafts 12 and 62 were deemed unable to rotate around the shafts. When the nut members 14, 64 are rotationally driven, the screw shafts 12, 62 are moved. In some cases, the nut members 14 and 64 are fixed to a fixed member and can be moved in the axial direction. The screw shafts 12, 62 arranged in the same direction are rotationally driven and moved together with the drive device. This may also be the case.

[0040] Although no other examples are given, the present invention can be modified and modified based on the knowledge of those skilled in the art. It can be implemented in a manner that includes both good and bad effects.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view of a feed screw device that is an embodiment of the present invention.

FIG. 2 is a right side view of the feed screw device in FIG. 1;

FIG. 3 is a sectional view taken along III-III in FIG. 1;

FIG. 4 is a partially cutaway front view of a feed screw device according to another embodiment of the present invention.

5 is a right side view of the feed screw device of FIG. 4. FIG.

6 is a diagram showing another aspect of the nut member in the feed screw device of FIG. 1. FIG.

7 is a right side view of the nut member of FIG. 6. FIG.

FIG. 8 is a sectional view showing another aspect of the bearing in the feed screw device of the present invention.

9 is a sectional view showing another arrangement of bearings in the feed screw device of FIG. 4. FIG.

[Explanation of symbols]

10,60: Feed screw device 12, 62: Screw shaft 14, 64, 100: Nut member 16a, 16b, 16c, 16d, 66: Thread groove 18, 72, 74: Through hole 22, 68, 70, 102: Support frame 30, 76, 120: Bearing 42,124: Inner circle 44,128: Outer ring 46: Ball (rolling element) 78: Spacer 90: Ring member 92, 126: Outer peripheral surface 130: Radial needle (rolling element) 132, 134: Thrust direction needle (rolling element)

──────────────────────────────────────────────── ─── Continuation of front page (72) Creator Masataka Inuzuka 15 Nakashitayashiki, Yanai, Shinshiro City, Aichi Prefecture (72) Creator Yoshikazu Kawai 26 Otogawa Kurozo, Kira-machi, Hazu-gun, Aichi Prefecture earth

Claims (4)

[Scope of utility model registration request] Claim 1: A state in which a screw shaft with a thread groove provided on the outer periphery and a nut member screwed onto the screw shaft are provided, and either the screw shaft or the nut member cannot rotate around the shaft. A feed screw device that moves the screw shaft and the nut member relative to each other in the axial direction by rotationally driving the other, the nut member being provided with a support frame provided with an insertion hole through which the screw shaft is inserted; An inner ring is fixed to the support frame, and an outer ring is provided to be rotatable relative to the inner ring via rolling elements and whose outer circumferential portion is brought into rolling contact with the thread groove, and is disposed around the insertion hole. A feed screw device characterized in that it is configured to include a plurality of bearings. 2. The bearing according to claim 1, wherein the bearing is disposed on the support frame in such a manner that its axial center is inclined with respect to the axial center of the screw shaft by the same angle as the lead angle of the thread groove. Lead screw device. 3. The thread groove has an arcuate cross-sectional shape, and the outer ring includes a ring member having a convex arc-shaped outer peripheral surface corresponding to the cross-sectional shape of the thread groove. The feed screw device according to claim 1 or 2, further comprising: a feed screw device. 4. The nut member includes a pair of the support frames on which the plurality of bearings are disposed, and
Any one of claims 1 to 3, wherein the pair of support frames are integrally formed via a spacer in such a manner that the outer rings of the bearings disposed on each support frame are pressed against the wall surface on the opposite side of the thread groove. The feed screw device described in .