TW201600770A - Ball screw device - Google Patents

Abstract

The ball screw device (120), which has a screw shaft (103) and a nut (101) that is screwed on the screw shaft (103) via multiple balls (106), comprises: a lubricant-containing body (108) that contacts the outer circumferential surface of the screw shaft (103) and supplies lubricant; and a heat generation-reducing mechanism for reducing heat generation in the lubricant-containing body (108). As a result, it is possible to reduce friction-induced heat generation in the lubricant-containing body that contacts the screw shaft. In particular, it is possible to limit frictional heat even in high speed, high load uses and to provide a ball screw device with which stable, long term supply of lubricant is possible.

Description

Ball screw device

The present invention relates to a ball screw device.

As a device for converting a rotary motion into a linear motion, a ball screw device is known. The structure of the ball screw device is such that a plurality of balls as a rotating body are interposed between the screw shaft and the nut, so that the movement is smooth and the feed precision is excellent, so that it is often used for a feed device for moving heavy objects and a workpiece. Feeding device, or precision positioning device, etc.

In the ball screw device, a plurality of balls are housed in a spiral ball rotation groove, and the ball rotation grooves are formed on the inner circumferential surface of the nut and the outer circumferential surface of the screw shaft inserted into the nut, with the nut and the nut The relative rotation of the screw shaft circulates between the ball return passage provided in the thick wall of the nut or the outer portion of the nut and the spiral ball rotation groove. There is a ball screw device having a structure in which a lubricant is supplied to the outer circumferential surface of the screw shaft, particularly the spiral ball rotation groove, in order to smoothly rotate the balls and reduce wear of the ball rotation grooves.

As a means for supplying a lubricant to the screw shaft of the ball screw device, an apparatus described in Japanese Laid-Open Patent Publication No. 2000-81103, and Japanese Patent Laid-Open No. Hei 10-265794 is known. It has a configuration in which a cylindrical lubricant-impregnated body containing a lubricant is attached to the end of the nut, and is held in such a manner that the inner peripheral portion thereof is slidably attached to the screw shaft, and the nut and the screw shaft are held. In the relative rotation, the lubricant is extruded from the lubricant containing body to the outer peripheral surface of the screw shaft, thereby No maintenance and long-term supply of lubricant.

Further, as another example, a ball screw device having a lubricant containing body having a sealing portion is disclosed in Japanese Laid-Open Patent Publication No. Hei 08-277900. As shown in FIG. 10, it has a structure in which the inner diameter part of the one end part of the nut 1 of the ball rotation groove 2 is formed in the inner peripheral surface, and the buried hole part 23 is formed in the inner-angle shape, and the cyclic lubricant containing body is formed. 21 is pressed into the buried hole portion 23, and the inner peripheral portion of the lubricant containing body 21 is brought into contact with the outer peripheral surface of the screw shaft 3, and further, the lubricant containing body that is in contact with the depth of the buried portion 23 The inner diameter portion of the inner surface of the inner surface of 21 is integrally formed with a sealing portion 22 which is press-contacted to the ball rotation groove 5 along the ball rotation groove 5 of the screw shaft 3. By the relative rotation of the nut 1 and the screw shaft 3, the balls 6 are rotated by the nut 1 and the ball rotation grooves 2, 5 of the screw shaft 3. With this configuration, the lubricant of the lubricant containing body 21 is applied to the outer peripheral surface of the screw shaft 3 and the ball rotating groove 5, and the sealing portion 22 can ensure dustproof between the screw shaft 3 and the nut 1.

Prior technical literature Patent literature

Patent Document 1: Japanese Patent Laid-Open Publication No. 2000-81103

Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 10-265794

Patent Document 3: Japanese Laid-Open Patent Publication No. 08-277900

In the conventional ball screw device in which the inner peripheral surface of the lubricant containing body is brought into contact with the screw shaft to supply the lubricant, the entire inner peripheral surface of the lubricant containing body is directly connected to the screw shaft. The frictional heat is generated by the relative rotation of the nut and the screw shaft during operation, so that the frictional heat of the lubricant containing body and the screw shaft generates friction heat, especially under the conditions of high speed and high load, the friction heat reaches a high temperature. As a result, the lubricant is dissolved and the oil is broken due to excessive discharge, and as a second factor, the material such as the waste of the lubricant contains deterioration or dissolution.

Further, in the ball screw device of Patent Document 3, the inner peripheral surface of the lubricant containing body 21 and the entire region of the sealing portion 22 integrally formed with the lubricant containing body 21 are slidably attached to the outer peripheral surface of the screw shaft 3 and the balls. The groove 5 is rotated, so that a large amount of heat is generated by friction, and the same problem as above may occur.

Accordingly, it is an object of the present invention to provide a ball screw device which can reduce the heat generated by friction of a lubricant contained in contact with a screw shaft, and can suppress friction heat even when used for high speed and high load applications, thereby being stable for a long period of time. Ground lubricant.

The present invention provides a ball screw device having a screw shaft and a nut that is screwed to the screw shaft via a plurality of balls, the ball screw device having a lubricant containing body and a peripheral portion of the screw shaft A lubricant is supplied in contact with the surface; and a heat reduction mechanism for reducing heat generation of the lubricant containing body.

According to the present invention, it is possible to obtain a ball screw device capable of reducing heat generated by friction on a contact surface between a lubricant containing body and a screw shaft, and capable of continuously supplying lubrication for a long period of time even for use in high speed and high load applications. Agent.

1, 101, 201‧‧ ‧ nuts

2, 5, 102, 105, 202, 205‧‧‧ balls rotating groove

3, 103, 203‧‧‧ screw shaft

6, 106‧‧‧ balls

21, 108, 208‧‧‧Lubricant inclusions

22‧‧‧ Sealing Department

23‧‧‧ buried hole

107, 207‧‧‧ ball return tube

108a, 208a‧‧‧ end face

108b, 208b‧‧‧ grooves

109, 209‧‧‧ shell

110‧‧‧Apartment

111‧‧‧ Sealing member

112‧‧‧fixed screw

115‧‧‧Lubricant Supply Department

116, 216‧‧‧ card stop

117, 217‧‧" ring spring

120, 130, 220‧‧‧ ball screw device

125, 126‧‧‧ axial access

127, 128‧‧‧ radial path

129‧‧‧Connected tube

131‧‧‧Axis access

208c‧‧‧ inner circumference

208d‧‧‧ Groove

208e‧‧‧ ribs

210‧‧‧ Body Department

211‧‧‧ Sealing members

212‧‧‧fixed screw

215‧‧‧Lubricant Supply Department

218‧‧‧Rolling surface

Fig. 1 is a partial longitudinal sectional view showing a ball screw device according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view showing the lubricant supply unit of the first embodiment in an exploded manner.

Fig. 3 is a perspective view showing a lubricant containing body according to the first embodiment.

Fig. 4 is a partial longitudinal sectional view showing a ball screw device according to a second embodiment of the present invention.

Fig. 5 is a partial longitudinal sectional view showing a ball screw device according to a third embodiment of the present invention.

Fig. 6 is a longitudinal sectional view showing the lubricant supply unit of the third embodiment in an exploded manner.

Fig. 7A is a perspective view showing a lubricant containing body according to a third embodiment, Fig. 7B is a view showing an end surface of the lubricant containing body according to the third embodiment, and Fig. 7C is a view showing an endless belt spring.

Fig. 8 is an exploded perspective view showing a second modification of the lubricant-containing body of the third embodiment.

Fig. 9 is an exploded perspective view showing a third modification of the lubricant-containing body of the third embodiment.

Fig. 10 is a partial longitudinal sectional view showing a conventional ball screw device having a lubricant containing body.

Next, the embodiments of the present invention will be specifically described with reference to the drawings.

(First embodiment)

Referring to Figs. 1 and 2, in the ball screw device 120 of the present embodiment, a ball rotation groove 102 is formed in a spiral shape on the inner circumferential surface of the cylindrical nut 101, and the screw shaft 103 is inserted into the nut 101. On the outer circumferential surface, a spiral ball rotation groove 105 is formed in a manner corresponding to the rotation groove 102 of the nut 101, and a plurality of balls 106 are interposed between the ball rotation grooves 102 and 105. A ball return pipe 107 is provided on the outer side of the nut 101, and both ends of the ball return pipe 107 communicate with both end portions of the ball rotation groove 102 on the nut side. With the relative rotational movement of the nut 101 and the screw shaft 103, the balls 106 perform a helical movement on the one hand in the nut 101, on the one hand in the nut 101, The nut 101 moves in the opposite direction to the direction in which the screw shaft 103 relatively moves, and each of the balls 106 repeats the cycle in which the groove end of the ball rotation groove 102 from the nut 101 is lifted to the ball return pipe 107 and The ball return pipe 107 moves in the relative movement direction of the nut 101, and the other end of the nut-side ball rotation groove 102 re-enters the ball rotation grooves 102 and 105 between the nut 101 and the screw shaft 103, and the nut 101 The inward nut 101 rotates in the opposite direction of the relative movement direction.

In order to smoothly rotate the balls 106 and reduce the wear of the ball rotating grooves 102 and 105, a lubricant supply portion 115 for supplying a lubricant to the screw shaft 103 is provided at an end portion of the nut 101. The lubricant supply unit 115 is composed of a lubricant containing body 108, a sealing member 111, and a cylindrical casing 109 that accommodates the lubricant. At the end of the nut 101 side of the casing 109, a ring body portion 110 having a diameter slightly smaller than the outer peripheral portion of the casing 109 is integrally formed, and the ring body portion 110 is inserted into the buried hole at the end of the nut 101 in an internal angle form. The housing 109 is fixed to the nut 101 by a fixing screw (not shown) that is screwed in from the radially outer side of the nut 101. The casing 109 and the ring portion 110 are preferably made of a material having a high thermal conductivity, and in the present embodiment, they are made of a metal. Further, the attachment of the casing 109 to the nut 101 is not limited to the above embodiment, and other known means may be employed.

For example, an annular sealing member 111 formed of synthetic rubber is fitted into the casing 109 so as to be in contact with the depth of the casing 109, and is fixed by a fixing screw 112 screwed in from the radially outer side of the casing 109. . In this state, the inner diameter portion of the sealing member 111 is pressed against the outer diameter portion of the screw shaft 103 and the ball rotation groove 105, thereby exerting a dustproof and sealing action. Further, the sealing member 111 may of course be formed of an elastomer other than synthetic rubber.

The lubricant supply unit 115 of the present invention will be further specifically described with reference to Fig. 1, Fig. 2 and Fig. 3. The lubricant containing body 108 is in contact with the outer end surface of the sealing member 111, that is, the end surface opposite to the nut 101. The method is housed in the casing 109. Lubricant contains body 108 The end surface, that is, the end surface 108a on the opposite side of the nut 101 is restrained by the locking pin 116 which is inserted from the radially outer side to the outer peripheral portion of the casing 109.

The lubricant-containing body 108 can effectively use the lubricant-containing polymer described in the above-mentioned Japanese Patent Publication No. 2000-81103 or Japanese Patent Application Laid-Open No. Hei 10-265794. As an example of the lubricant-containing polymer which is suitable for use in the present invention, it is a solid shape: a polyolefin resin having substantially the same chemical structure selected from polyethylene, polypropylene, polybutene, polymethylpentene or the like. In the synthetic resin in the group, a paraffinic hydrocarbon oil such as a polyester oil, a naphthenic hydrocarbon oil, a mineral oil, or a dialkyl diphenyl ether oil is added as a lubricant in a form of a single form or a mixed oil. Any one of an ester oil such as an ether oil or a phthalate ester is prepared as a raw material, and the raw material is heated and plasticized at a temperature equal to or higher than the melting point of the resin, and then solidified by cooling. Further, depending on the case, various additives such as an antioxidant, a rust preventive, an anti-wear agent, an antifoaming agent, and an extreme pressure agent may be added to the lubricant in advance.

As is clear from Fig. 3, the lubricant containing body 108 is composed of two semi-cylindrical bodies facing each other, and a circumferential groove 108b is formed at a substantially central portion of the outer peripheral surface of each of the semi-cylindrical bodies. The semi-cylindrical bodies are opposed to each other and the endless belt spring 117 of FIG. 2 is fitted to the outer peripheral groove 108b, whereby a cylindrical lubricant containing body 108 is obtained. The endless belt spring 117 not only has a function of combining the two semi-cylindrical bodies of the lubricant-containing body 108, but also has a function of pressurizing the lubricant-containing body 108 inward in the radial direction to allow the lubricant to more effectively ooze out.

When the lubricant containing body 108 is housed in the casing 109, the inner peripheral surface of the lubricant containing body 108 comes into contact with the outer peripheral surface of the screw shaft 103, and as the nut 101 and the screw shaft 103 rotate relative to each other, The lubricant oozes out from the lubricant containing body 108 and supplies the lubricant to the screw shaft 103.

As shown in FIG. 1 and FIG. 2, a pair of axial passages 125 and 126 extending in the axial direction are bored in the thick wall of the main body portion of the nut 101, and the outer periphery of the end portion of the self-nut 101 is worn. The faces communicate with the radial passages 127, 128 of the respective axial passages 125, 126. The distal end portions of the respective axial passages 125 and 126 on the opposite sides of the radial passages 127 and 128 are inserted through the nut 101 and communicated to the connecting tube 129 disposed on the outer side of the front end surface of the nut 101. The radial passages 127 and 128 can be connected to an external coolant pump (not shown) via a suitable flexible tube, for example, a flexible hose or the like.

The cooling liquid such as water or oil introduced from the coolant pump to the radial passage 127 is sequentially returned to the coolant pump from the radial passage 128 through the axial passage 125, the connecting pipe 129, and the axial passage 126, and Path loop. In this manner, the nut 101 is cooled by the coolant flowing in the nut 101, and the cooling action can be transmitted to the lubricant supply portion 115 at the end of the nut 101, thereby cooling the lubricant containing body 108. Thereby, it is possible to effectively suppress the temperature rise of the lubricant containing body 108 due to frictional heating with the screw shaft 103 in operation, even when the ball screw device is used for applications in which a large amount of frictional heat is generally generated, such as high speed or high load. Further, it is possible to prevent oil breakage due to excessive bleeding of the lubricant contained in the temperature rise, or deterioration or dissolution of the material of the lubricant-containing body 108, and it is possible to stably supply the lubricant for a long period of time.

Specifically, when the nut 101 is cooled by the cooling liquid, the cooling action is transmitted from the end portion of the nut 101 to the lubricant supply portion 115, and the lubricant containing body 108 and the sealing member 111 are cooled. In the present embodiment, the lubricant containing body 108 and the sealing member 111 are housed in a casing 109 made of a metal having a large thermal conductivity. Therefore, the cooling action is transmitted to the lubricant containing body 108 and the sealing member 111 via the casing 109, and the lubricant containing body 108 and the sealing member 111 are cooled from the entire outer peripheral surface thereof. In particular, in the present embodiment, the ring body portion 110 of the casing 109 extends to the vicinity of the radial passages 127, 128 of the nut 101, so that the cooling effect can be further improved. It is transmitted to the lubricant containing body 108 and the sealing member 111.

When the nut 101 is cooled by the coolant, the screw shaft 103 is cooled by the balls 106, and the lubricant containing body 108 and the sealing member 111 which are in contact with the screw shaft 103 are also cooled, so that the entire ball screw device is provided. 120 cooling.

As described above, the lubricant containing body 108 is effectively cooled from both the radially outer side and the radially inner side, so that the temperature rise due to friction with the screw shaft 103 during operation can be effectively suppressed. And can maximize the above effects.

(Second embodiment)

In the above-described first embodiment, the example in which the nut 101 side of the ball screw device 120 is directly cooled is shown. However, the present invention can also form a coolant flow path in the screw shaft 103 to make the screw shaft 103 side. cool down.

The ball screw device 130 of this embodiment shown in Fig. 4 shows the cooling structure of the screw shaft 103. In the ball screw device 130, the same components as those in the above-described first embodiment are denoted by the same reference numerals and will not be described.

A shaft core passage 131 is formed, and a shaft core of the screw shaft 103 penetrates the shaft core passage 131 in the axial direction, and the shaft core passage 131 is coupled to both ends of the screw shaft 103 via a joint (not shown) and a flexible tube. In the coolant pump, the coolant circulates in the core passage 131 and the coolant pump, whereby the screw shaft 103 is cooled, and the cooling action can be transmitted to the lubricant containing body 108 of the lubricant supply portion 115 to make the lubricant The inclusion body 108 is cooled. Thereby, the same effects as those of the above-described first embodiment can be exhibited.

Specifically, when the screw shaft 103 is cooled by the cooling liquid, the lubricant containing body 108 and the sealing member 111 that are in contact with the screw shaft 103 can be cooled.

Further, when the screw shaft 103 is cooled by the coolant, the nut 101 is also cooled by the balls 106. Thereby, the cooling action is transmitted from the end portion of the nut 101 to the lubricant supply portion 115, and the lubricant containing body 108 and the sealing member 111 are cooled, thereby cooling the entire ball screw device 130. Similarly to the above-described first embodiment, the lubricant containing body 108 and the sealing member 111 are housed in a casing 109 made of a metal having a large thermal conductivity. Therefore, the cooling action is transmitted to the lubricant containing body 108 and the sealing member 111 via the casing 109, and the lubricant containing body 108 and the sealing member 111 are cooled from the entire outer peripheral surface thereof. In particular, in the present embodiment, since the ring body portion 110 of the casing 109 is inserted into the end portion of the nut 101 in the form of an internal angle, it is possible to ensure a large contact area of the casing 109 with respect to the nut 101. Therefore, the cooling action can be more smoothly transmitted to the lubricant containing body 108 and the sealing member 111.

As described above, since the lubricant containing body 108 is effectively cooled from both the radially inner side and the radially outer side, it is possible to effectively suppress the screw shaft 103 in operation as in the first embodiment. The temperature rise due to frictional heat generation can maximize the above effects.

Further, in the ball screw device 130 of the present embodiment, a cooling fan may be disposed instead of the cooling structure, for example, a cooling fan is disposed on an extension line of the screw shaft 103 in the axial direction, that is, above the FIG. The entire ball screw device 130 is cooled. In this case, the lubricant containing body 108 can be directly cooled by the air blow from the cooling fan. Further, since the casing 109 is directly cooled by the air blow from the cooling fan, the lubricant containing body 108 and the sealing member 111 can be cooled from the entire outer peripheral surface thereof.

As described above, in the cooling form of the present invention, the nut 101 is cooled, the screw shaft 103 is cooled, and the entire ball screw device is cooled by the cooling fan. Although the form has been described, the form in which the nut 101 is cooled and the form in which the screw shaft 103 is cooled may be combined, and the cooling fan may be combined in the form in which the nut 101 is cooled. In the form in which the screw shaft 103 is cooled, a form of a cooling fan is combined.

Further, in the ball screw devices 120 and 130 of Figs. 1 and 4, the circulation form of the balls 106 is a case where the ball return pipe 107 is used. However, the present invention is also applicable to other ball circulation modes, for example, for example. In a ball screw device such as an end deflector type, a stopper type, and an end cap type.

Further, the shape of the casing 109, the shape of the lubricant containing body 108, the arrangement to the screw shaft 103, the number, and the like are not limited to the above, as long as the cooling action can be transmitted from the casing 109 to the lubricant containing body 108. The way you can touch it. The casing 109 and the ring portion 110 are not limited to metal, and may be made of other materials having a large thermal conductivity.

(Third embodiment)

Referring to Fig. 5 and Fig. 6, in the ball screw device 220 of the present embodiment, a ball rotation groove 202 is formed in a spiral shape on the inner circumferential surface of the cylindrical nut 201, and the screw shaft 203 is inserted into the nut 201. On the outer circumferential surface, a spiral ball rotation groove 205 is formed corresponding to the rotation groove 202 of the nut 201, and a plurality of balls 206 are interposed between the ball rotation grooves 202 and 205. A ball return pipe 207 is provided on the outer side of the nut 201, and both ends of the ball return pipe 207 communicate with both end portions of the ball rotation groove 202 on the nut side. With the relative rotational movement of the nut 201 and the screw shaft 203, the balls 206 perform a helical movement on the one hand in the nut 201, on the one hand in the nut 201, in the direction of the relative movement of the nut 201 relative to the screw shaft 203. Moving in the opposite direction, the balls 206 are repeatedly cycled as follows: the groove end of the ball rotation groove 202 from the nut 201 is lifted to the ball return pipe 207 and moved in the ball return pipe 207 in the relative movement direction of the nut 201. Snail The other end of the cap side ball rotation groove 202 re-enters the ball rotation groove 202, 205 between the nut 201 and the screw shaft 203, and rotates in the nut 201 in the opposite direction to the relative movement direction of the nut 201.

In order to smoothly rotate the balls 206 and reduce the wear of the ball rotating grooves 202 and 205, a lubricant supply portion 215 for supplying a lubricant to the screw shaft 203 is provided at an end portion of the nut 201. The lubricant supply unit 215 is composed of a lubricant containing body 208, a sealing member 211, and a cylindrical casing 209 that accommodates the lubricant. At the end of the nut 201 side of the housing 209, a ring body portion 210 having a diameter slightly smaller than the outer peripheral portion of the housing 209 is integrally formed, and the ring body portion 210 is inserted into the buried hole at the end of the nut 201 in an internal angle form. The housing 209 is fixed to the nut 201 by a fixing screw (not shown) that is screwed in from the radially outer side of the nut 201. Further, the attachment of the casing 209 to the nut 201 is not limited to the above embodiment, and other known means may be employed.

For example, the annular sealing member 211 formed of synthetic rubber is fitted into the casing 209 so as to be in contact with the depth of the casing 209, and is fixed by a fixing screw 212 screwed in from the radially outer side of the casing 209. . In this state, the inner diameter portion of the sealing member 211 is pressed against the outer diameter portion of the screw shaft 203 and the ball rotation groove 205, thereby exerting a dustproof and sealing action. Further, the sealing member 211 may of course be formed of an elastomer other than synthetic rubber.

Referring to Fig. 5, Fig. 6, and Fig. 7, the lubricant supply unit 215 of the present invention will be further specifically described. The lubricant containing body 208 is in contact with the outer end surface of the sealing member 211, that is, the end surface on the opposite side of the nut 201. The method is housed in the casing 209. The end surface 208a of the outer end surface of the lubricant containing body 208, that is, the opposite side of the nut 201 is restrained by the locking pin 216 which is inserted from the radially outer side to the outer peripheral portion of the casing 209.

The lubricant-containing polymer 208 can effectively use the lubricant-containing polymer described in Patent Document 1 or Patent Document 2 described above. As a lubricant containing a polymer suitable for use in the present invention For example, it is a solid shape as a lubricant in a synthetic resin selected from the group consisting of polyolefin resins having substantially the same chemical structure such as polyethylene, polypropylene, polybutene, and polymethylpentene. An ester oil such as a paraffinic hydrocarbon oil such as a polyester oil, a naphthenic hydrocarbon oil, a mineral oil or a dialkyl diphenyl ether oil, or an ester such as a phthalate ester is added in the form of a single form or a mixed oil. Any one of oil or the like is prepared as a raw material, and the raw material is heated and plasticized at a temperature equal to or higher than the melting point of the resin, and then solidified by cooling; and, depending on the case, it may be a lubricant Various additives such as an antioxidant, a rust preventive, an anti-wear agent, an antifoaming agent, and an extreme pressure agent are added in advance.

As clearly shown in FIG. 7A and FIG. 7B, the lubricant containing body 208 is composed of two semi-cylindrical bodies facing each other, and a circumferential groove 208b is formed in a substantially central portion of the outer peripheral surface of each of the semi-cylindrical bodies. The semi-cylindrical bodies are opposed to each other and the endless belt springs 217 of FIGS. 6 and 7C are fitted to the outer peripheral grooves 208b, whereby a cylindrical lubricant containing body 208 is obtained. The endless belt spring 217 has a function of combining the two semi-cylindrical bodies of the lubricant containing body 208 with each other, and has a function of pressurizing the lubricant containing body 208 radially inward to allow the lubricant to more effectively bleed out.

When the lubricant containing body 208 is housed in the casing 209, the inner peripheral surface of the lubricant containing body 208 is in contact with the outer peripheral surface of the screw shaft 203, and as the nut 201 and the screw shaft 203 rotate relative to each other, The lubricant oozes out from the lubricant containing body 208 and supplies the lubricant to the screw shaft 203.

Here, the uneven portion is formed on the inner circumferential surface 208c of the lubricant containing body 208. In the present embodiment, as shown in FIG. 7A, the uneven portion is formed by a embossed surface 218 formed by embossing the inner circumferential surface 208c of the lubricant containing body 208 into a lattice shape. The convex portion of the embossed surface 218 is in contact with the outer peripheral surface of the screw shaft 203, and the concave portion of the embossed surface 218 is not in contact with the screw shaft 203. Therefore, the inner peripheral surface 208c of the lubricant containing body 208 is not formed with unevenness. In the case of the portion, the contact area of the lubricant containing body 208 which is in contact with the outer peripheral surface of the screw shaft 203 can be reduced. Thereby, the frictional force between the lubricant containing body 208 and the screw shaft 203 is reduced, and heat generation due to frictional contact is reduced. Therefore, even when the ball screw device is used for applications in which a large amount of frictional heat is generated, such as high speed or high load, it is possible to prevent oil breakage or lubricant inclusion caused by excessive bleeding of the lubricant contained due to temperature rise. The material of the body 208 is deteriorated, dissolved, and the like, so that the lubricant can be stably supplied for a long period of time. Further, the embossed surface 218 is not limited to the twill, and may be a plain weave or a stripe.

(First Modification)

The uneven portion formed on the inner circumferential surface 208c of the lubricant containing body 208 is not limited to the embossed surface as described above, as long as it can leaching and oozing the lubricant of the lubricant containing body 208 without affecting the screw shaft 203. It is sufficient to reduce the substantial contact area with the screw shaft 203 in the range, thereby suppressing frictional heat generation. For example, as the first modification of the lubricant containing body 208, the uneven portion of the inner peripheral surface 208c may be formed of a pit-processed surface (not shown). In this example, a plurality of concave recesses are formed on the inner circumferential surface 208c of the lubricant containing body 208, and are, for example, a plurality of small hemispherical recesses (not shown) formed on the surface of the golf ball. By forming the lubricant containing body 208 into two semi-cylindrical bodies, the formation of such a pit-processed surface is facilitated.

(Second modification)

FIG. 8 is an exploded perspective view showing a second modification of the lubricant containing body 208. In this case, at least one groove 208d extending in the circumferential direction is formed as an uneven portion on the inner circumferential surface 208c of the lubricant containing body 208. In the present modification, two grooves 208d are formed. The groove 208d is not in direct contact with the screw shaft 203, whereby the contact area of the lubricant containing body 208 which is in contact with the outer peripheral surface of the screw shaft 203 is reduced, so that generation of a large amount of frictional heat can be suppressed.

(Third Modification)

FIG. 9 is an exploded perspective view showing a third modification of the lubricant containing body 208. In this case, at least one of the ridges 208e extending in the circumferential direction is formed as the uneven portion on the inner peripheral surface 208c of the lubricant containing body 208, and in the present modification, one ridge 208e is formed. The rib 208e is in contact with the outer circumferential surface of the screw shaft 203, and the portion other than the rib 208e is not slidably connected to the outer circumferential surface of the screw shaft 203. Therefore, as in the second modification, the frictional heat can be reduced by reducing the contact area. And can suppress the temperature rise. Of course, a plurality of ribs 208e may be provided, and in order to allow the lubricant to effectively ooze out, the inner peripheral surface of the rib 208e is formed in a smooth and wide width.

In the above-described first to third modifications, the cylindrical lubricant containing members 208 are each composed of two semi-cylindrical bodies, and an annular groove 208b for arranging the annular ring-shaped spring 217 is formed on the outer periphery thereof. The spring 217 is used to fasten the lubricant containing body 208 radially inward, so that the lubricant can be more effectively exuded. In the two semi-cylindrical bodies, the uneven processing of the inner circumferential surface of the lubricant-containing body 208 is easily performed. However, in particular, in the case of the second and third modifications, the two semi-cylindrical bodies may not be provided. The shape of two semi-cylindrical bodies. Further, the uneven portion of the lubricant-containing body 208 has been described as an example in which the inner peripheral surface 208c is subjected to embossing, pit processing, groove formation, and ridge formation, but it may be a combination of these. . In addition, the material, the shape, the arrangement to the screw shaft 203, the arrangement of the uneven portions, the number, and the like of the lubricant containing body 208 are not particularly limited as long as the object can be achieved. The uneven portion of the inner circumferential surface 208c of the lubricant containing body 208 is for reducing the contact pressure between the lubricant containing body 208 and the screw shaft 203, and suppressing the increase in the frictional heat thereof, and may be set in the axial direction in addition to the above. A plurality of grooves or ribs extending. Further, the uneven portion of the inner circumferential surface 208c of the lubricant containing body 208 may be formed of an embossed surface, and the embossed surface may be uniformly provided with a plurality of protrusions on the inner circumferential surface 208c.

Further, in the ball screw device 220 of Fig. 5, the circulation form of the balls 206 is a case where the ball return pipe 207 is used. However, the present invention is also applicable to other ball circulation modes, such as a deflector type, In the ball screw device such as the stopper type and the end cover type.

101‧‧‧ nuts

102, 105‧‧‧Rolling groove

103‧‧‧ Screw shaft

106‧‧‧ balls

107‧‧‧Ball return tube

108‧‧‧Lubricant inclusions

108a‧‧‧ end face

108b‧‧‧ Groove

109‧‧‧Shell

110‧‧‧Apartment

111‧‧‧ Sealing member

112‧‧‧fixed screw

115‧‧‧Lubricant Supply Department

116‧‧‧ card sales

117‧‧‧ring spring

120‧‧‧Rolling screw device

125, 126‧‧‧ axial access

127, 128‧‧‧ radial path

129‧‧‧Connected tube

Claims (17)

A ball screw device comprising a screw shaft and a nut that is screwed to the screw shaft via a plurality of balls, and has a lubricant containing body that is in contact with an outer circumferential surface of the screw shaft to supply a lubricant; And a heat reduction mechanism for reducing heat generation of the lubricant containing body. A ball screw device according to claim 1, wherein the heat generation reducing means is provided with a cooling passage for allowing the coolant to flow to at least one of the nut and the screw shaft. The ball screw device according to claim 2, wherein the end portion of the nut in the axial direction has a casing for accommodating the lubricant containing body; and the lubricant containing system surrounds the cylindrical shape of the screw shaft, and The outer peripheral surface is fitted to the casing, and the screw shaft is slidably inserted into the lubricant containing body. The ball screw device of claim 3, wherein the casing is made of metal. The ball screw device according to claim 4, wherein a hole is formed in an end surface of the nut in the axial direction; the casing is formed by a holding portion and a fitting portion, and the holding portion holds the lubricant The fitting portion is integrally provided to the holding portion and fitted to the buried hole portion of the nut. The ball screw device of claim 5, wherein the cooling passage includes a nut side passage formed in the nut along an axial direction of the nut; and the fitting of the housing The portion extends to the vicinity of the nut side passage of the nut. The ball screw device of claim 6, wherein the cooling passage comprises The nut side passage of the nut and the screw shaft side passage formed in the screw shaft along the axial direction of the screw shaft. The ball screw device according to claim 5, wherein the cooling passage includes a screw shaft side passage formed in the screw shaft along an axial direction of the screw shaft. The ball screw device according to any one of claims 3 to 8, wherein the annular sealing member that seals the outer periphery of the screw shaft is housed in the casing adjacent to the lubricant containing body. The ball screw device according to the first aspect of the invention, wherein the heat generation reducing means is formed with a contact portion that reduces an area of the contact portion at a contact portion of the lubricant containing body that is in contact with the outer peripheral surface of the screw shaft. unit. The ball screw device according to claim 10, wherein the lubricant containing body has a cylindrical shape; the screw shaft is slidably inserted into the lubricant containing body; and the inner circumferential surface of the lubricant containing body is formed. There are the above-mentioned uneven portions. The ball screw device according to claim 11, wherein the uneven portion of the lubricant containing body is formed by embossing the inner peripheral surface. The ball screw device according to claim 11, wherein the uneven portion of the lubricant containing body is formed by performing a pit process on the inner peripheral surface. The ball screw device according to claim 11, wherein the uneven portion of the lubricant containing body is formed by forming a groove portion extending in the circumferential direction on the inner circumferential surface. The ball screw device of claim 11, wherein the lubricant contains The uneven portion is formed by forming a projection extending in the circumferential direction on the inner circumferential surface. The ball screw device according to claim 11, wherein the lubricant containing system is composed of two semi-cylindrical bodies, and the ring-shaped spring is attached to the periphery of the lubricant containing body to make the above-mentioned 2 The semi-cylindrical bodies are cylindrical. The ball screw device according to any one of claims 11 to 16, wherein an annular sealing member that seals the outer circumference of the screw shaft is provided adjacent to the lubricant containing body.