WO2011024450A1 - ボールねじ装置 - Google Patents
ボールねじ装置 Download PDFInfo
- Publication number
- WO2011024450A1 WO2011024450A1 PCT/JP2010/005236 JP2010005236W WO2011024450A1 WO 2011024450 A1 WO2011024450 A1 WO 2011024450A1 JP 2010005236 W JP2010005236 W JP 2010005236W WO 2011024450 A1 WO2011024450 A1 WO 2011024450A1
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- WIPO (PCT)
- Prior art keywords
- nut
- hole
- ball screw
- cooling
- screw device
- Prior art date
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/048—Type of gearings to be lubricated, cooled or heated
- F16H57/0497—Screw mechanisms
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H57/00—General details of gearing
- F16H57/04—Features relating to lubrication or cooling or heating
- F16H57/0412—Cooling or heating; Control of temperature
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H25/00—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms
- F16H25/18—Gearings comprising primarily only cams, cam-followers and screw-and-nut mechanisms for conveying or interconverting oscillating or reciprocating motions
- F16H25/20—Screw mechanisms
- F16H25/22—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
- F16H25/2204—Screw mechanisms with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members with balls
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19642—Directly cooperating gears
- Y10T74/19698—Spiral
- Y10T74/19702—Screw and nut
- Y10T74/19707—Plural longitudinally variably spaced nuts
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19642—Directly cooperating gears
- Y10T74/19698—Spiral
- Y10T74/19702—Screw and nut
- Y10T74/19744—Rolling element engaging thread
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T74/00—Machine element or mechanism
- Y10T74/19—Gearing
- Y10T74/19642—Directly cooperating gears
- Y10T74/19698—Spiral
- Y10T74/19702—Screw and nut
- Y10T74/19744—Rolling element engaging thread
- Y10T74/19749—Recirculating rolling elements
Definitions
- the present invention relates to a ball screw device, and more particularly to a ball screw device capable of cooling a nut.
- Patent Document 2 As a technique for cooling the feed nut, there is one disclosed in Patent Document 2. Specifically, this is a technique of passing a cooling medium through a coolant through hole (hereinafter referred to as a through hole) provided in the axial direction of the feed nut and cooling the feed nut.
- a coolant through hole hereinafter referred to as a through hole
- the temperature rise value ⁇ of the screw device is represented by the following formula (1).
- t is the elapsed time
- CM is the heat capacity of the screw device
- ⁇ is the unit time from the screw device
- Q is the amount of heat per unit time generated from the nut. is there.
- Q in the formula (1) is represented by the following formula (2).
- T is the dynamic friction torque
- n is the rotational speed of the shaft.
- FIGS. 7 and 8 are schematic diagrams showing the relationship between the preload direction and the heat shrinkage direction of the nut for each preload type.
- FIG. 7 is a view showing a preload form in a two-point contact state where the preload direction is the compression direction
- FIG. 8 is a view showing an oversized ball preload state.
- the ball screw device 1 includes a screw shaft 10 and a nut 20 that is screwed to the screw shaft 10 via a plurality of rolling elements 30.
- the rolling element 30 is preloaded between the screw groove 10 a of the screw shaft 10 and the screw groove 20 a of the nut 20.
- Non-Patent Document 1 the cooling effect varies greatly depending on the diameter of the through-hole through which the coolant passes when the nut of the ball screw device is cooled. The change in the cooling effect was confirmed by experiments.
- the present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to provide a ball screw device for cooling by passing a cooling medium through a through hole provided in an axial direction in the nut.
- An object of the present invention is to provide a ball screw device having as high a cooling effect as possible.
- the present inventors have conducted intensive studies. As a result, by adopting a preload type in which the total preload load hardly increases, the dynamic friction torque hardly increases even when the nut contracts due to cooling. I found out. Further, the inventors of the present invention, in a ball screw that performs cooling by passing a cooling medium through a through hole provided in the axial direction of the nut, a ratio L between the axial length L of the through hole and the diameter D of the through hole. It has been found that by defining / D, the cooling effect is made as high as possible and does not cause excessive reduction in processing efficiency or increase in pressure loss.
- the ball screw apparatus which concerns on one embodiment of this invention for solving the said subject is a screw shaft and the said screw shaft through several rolling elements.
- a ball screw device includes a screw shaft, a nut that is screwed to the screw shaft via a plurality of rolling elements, and a cooling medium in a through hole that is provided in the axial direction of the nut.
- the ratio (L / D) between the axial length L of the through hole and the diameter D of the through hole is defined by the following formula (A).
- a ball screw device includes a screw shaft, a nut that is screwed to the screw shaft via a plurality of rolling elements, and a cooling unit that cools the nut. Between the screw groove of the screw shaft and the screw groove of the nut, the plurality of rolling elements provided with a preload in a direction opposite to the contraction direction of the nut generated when the nut is cooled are incorporated. It is characterized by that.
- a ball screw device includes a screw shaft, a nut that is screwed to the screw shaft via a plurality of rolling elements, and a cooling unit that cools the nut.
- the nut is a double nut in which two nuts are connected via a spacer, and the two nuts and the spacer are formed with a coolant through hole through which the coolant from the cooling unit passes, O-rings are provided at both openings of the through hole for coolant of the seat, and the shrinkage of the nut that occurs when the nut is cooled is between the screw groove of the screw shaft and the screw groove of the nut.
- the plurality of rolling elements provided with a preload in the direction opposite to the direction are incorporated.
- the cooling portion is provided in the nut, and the preloading method of the nut is the two-point contact preload in the pulling direction.
- the contraction in the axial direction acts to alleviate this, the total preload is hardly increased. Therefore, it is possible to provide a ball screw device in which the dynamic friction torque hardly increases even when the nut contracts due to cooling. That is, it is possible to prevent the temperature of the ball screw from increasing due to an increase in the dynamic friction torque, and as a result, it is possible to provide a ball screw device that makes the nut cooling effect as high as possible.
- the ratio (L / D) between the axial length L of the through hole and the diameter D of the through hole is defined by the above formula (A).
- the increase in the preload torque at the time of cooling of a nut can be prevented.
- the relationship between the cooling effect and L / D as a calculation result when the axial length L of the through hole 20b is fixed and only the diameter D of the through hole 20b is changed is shown. It is a graph.
- it is a graph which shows the relationship between L / D, a cooling effect, and processing efficiency when verifying processing efficiency from the maximum feed rate which can be processed, maintaining the shape and surface roughness of the through-hole 20b. .
- FIG. 10 is a cross-sectional view showing a configuration of a ball screw device according to a fifth embodiment, wherein (a) is a cross-sectional view taken along the line 15a-15a in FIG. 1, and (b) is an enlarged view of a portion A in (a). It is a perspective view which shows the structure of the insertion member of the ball screw apparatus which concerns on 5th Embodiment.
- FIG. 1 is a cross-sectional view along the axial direction showing the configuration of the ball screw device according to the present embodiment.
- the ball screw device 1 of this embodiment includes a screw shaft 10 and a nut 20.
- the screw shaft 10 and the nut 20 are screwed together via a plurality of rolling elements 30.
- the nut 20 is formed in a cylindrical shape with an inner diameter larger than the outer diameter of the screw shaft 10.
- a screw groove 20 a is formed on the inner peripheral surface of the nut 20 so as to face the screw groove 10 a formed in a spiral shape on the outer peripheral surface of the screw shaft 10.
- the rolling element 30 can roll on the rolling path formed by the thread groove 10a and the thread groove 20a.
- the nut 20 is formed with a through hole 20b penetrating in the axial direction.
- the through hole 20b is used as a passage for the cooling medium, and a circulation device (not shown) for circulating the cooling medium in the through hole 20b is connected to the through hole 20b.
- the circulation device and the through hole 20b constitute the cooling unit 40.
- the nut 20 is cooled by circulating the cooling medium in the through hole 20b by a circulation device (not shown).
- FIG. 2 is a diagram showing the relationship between the preload state and the contraction in the two-point contact state where the tension direction is the preload direction.
- the heat shrinkage f 1 in the radial direction acts in a direction to increase the preload F a0
- heat shrinkage in the axial direction f 2 is to act to alleviate this, preload the total hardly increases.
- the two-point contact preload in the tensile direction is applied to the nut 20, so that the ball screw device 1 can be efficiently manufactured without increasing the preload torque even when the nut 20 is cooled. The whole can be cooled.
- FIG. 3 is a view showing a ball screw device according to the second embodiment. As shown in FIG. 3, this embodiment employs a double nut preload system, whereas the first embodiment employs an offset lead preload as the preload system.
- the ball screw device 1 of the present embodiment includes a first nut 20 ⁇ / b> A and a second nut that are screwed onto a common screw shaft 10 via a plurality of rolling elements 30. 20B and a spacer 50.
- the spacer 50 has an annular shape having substantially the same inner diameter as the inner diameters of the first nut 20A and the second nut 20B, and prevents relative rotation between the first nut 20A and the second nut 20B.
- a plurality of rolling elements 30 incorporated between the thread grooves 21 a and 22 a of the first nut 20 ⁇ / b> A and the second nut 20 ⁇ / b> B and the thread groove 10 a of the ball screw 10.
- a preload in a two-point contact state is applied with a preload load Fa0 .
- the preload direction is the tensile direction as in the first embodiment.
- FIG. 4 shows the temperature rise value and torque of the nut when the ball screw device of the first embodiment (see FIG. 1) is driven as the ball screw device of Example 1 and the nut is cooled during the driving. It is a graph which shows the result measured simultaneously.
- FIG. 5 is a graph showing the results of simultaneously measuring the temperature rise value and torque of the nut when the ball screw device of Comparative Example 1 was driven and the nut was cooled during the driving.
- the configuration of the ball screw device of Example 1 and Comparative Example 1 is shown in Table 1, the driving conditions of Example 1 and Comparative Example 1 are shown in Table 2, and the cooling conditions of Example 1 and Comparative Example 1 are shown in Table 3. .
- the configuration of the ball screw device of Comparative Example 1 includes a plurality of rolling elements 30 that have been oversized ball preloaded (four-point contact preload) between the thread groove 10a and the thread groove 20a. Is different from the first embodiment. 4 and 5, the time when the temperature of the nut suddenly decreases is the start of cooling.
- Example 1 As shown in FIGS. 4 and 5, it can be seen that in both Example 1 and Comparative Example 1, if the cooling is started, the temperature of the nut decreases, but the ball screw device of Example 1 decreases the temperature of the shaft. Can be seen to be large. In the feed system driven by the ball screw device, the temperature change of the shaft that directly affects the table accuracy becomes important. When attention is paid to the change in torque, in Comparative Example 1, the torque increases up to about twice that before cooling. This is because the nut undergoes heat shrinkage due to cooling, the direction of the heat shrinkage coincides with the preload direction, and the preload load is high. This heat generation diminishes the heat dissipation effect by cooling, and as a result, the cooling effect as a whole is reduced. Moreover, an excessive preload is caused, and as a result, the lifetime of the ball screw device is reduced.
- FIG. 9 is a side view showing the configuration of the ball screw device according to the third embodiment.
- the ball screw device 1 of this embodiment includes a screw shaft 10 and a nut 20.
- the screw shaft 10 and the nut 20 are screwed together via a plurality of rolling elements 30.
- the nut 20 is formed in a cylindrical shape with an inner diameter larger than the outer diameter of the screw shaft 10.
- a screw groove 20 a is formed on the inner peripheral surface of the nut 20 so as to face the screw groove 10 a formed in a spiral shape on the outer peripheral surface of the screw shaft 10.
- the rolling element 30 can roll on the rolling path formed by the thread groove 10a and the thread groove 20a.
- the through hole 20b penetrating in the axial direction is formed in the nut 20 (in FIG. 9, three through holes 20b are formed in the axial direction of the nut 20).
- the through hole 20 b is used as a passage for the cooling medium, and a circulation device (not shown) for circulating the cooling medium in the through hole 20 b is connected to the ball screw device 1.
- the circulation device and the through hole 20b constitute the cooling unit 40.
- the cooling unit 40 includes a pipe 41 that connects the circulation device and the through hole 20b to allow the cooling medium to flow into the through hole 20b, and a pipe 41 that allows the cooling medium to flow out from the through hole 20b.
- the nut 20 is cooled by circulating the cooling medium in the through hole 20b by a circulation device (not shown).
- the heat flow Q ′ when the refrigerant flows in a turbulent state in the through hole 20b is ⁇ : Heat transfer coefficient ⁇ : Temperature difference between the screw shaft 10 and the cooling medium F: When the area of the surface in contact with the cooling medium in the screw shaft 10 is expressed by the following formula (3).
- the heat transfer coefficient ⁇ and the area F of the surface in contact with the cooling medium in the screw shaft 10 are: ⁇ : Thermal conductivity of fluid D: Diameter of through hole 20b Nu m : Nusselt number L: When the length in the axial direction of the through hole 20b is given, it is expressed by the following formulas (4) and (5).
- the Nusselt number Nu m is Re m : Reynolds number Pr m : Prandtl number Is expressed by the following formula (6).
- the Reynolds number Re m and the Prandtl number Pr m are u m : Flow velocity of the cooling medium v: Kinematic viscosity of the cooling medium a: The temperature conductivity of the cooling medium is expressed by the following formulas (7) and (8), respectively.
- the flow velocity u m of the cooling medium is w: Flow rate of the cooling medium A: When the cross-sectional area of the through hole 20b is used, it is expressed by the following formula (9).
- the cross-sectional area A of the through hole 20b is represented by the following formula (10).
- Equation (11) is a function of the length of the through hole 20 through which the coolant passes and the diameter of the through hole 20 if the type and flow rate of the cooling medium do not change, and the longer the through hole 20 is, the more heat exchange is performed. In other words, the smaller the diameter of the through hole 20, the more heat exchange is performed. That is, the cooling effect is high. When this is replaced with the design of the nut 20, it can be said that the cooling effect is higher when L / D, which is the ratio between the axial length L of the through hole 20 and the diameter D of the through hole 20 b, is larger.
- the axial length L of the through hole 20 is often determined by the load condition, the required life, the required accuracy, etc., and is important when designing the nut 20 having a cooling part.
- the parameter is the diameter D of the through hole 20b.
- L / D is preferably set as large as possible by the following formula (12).
- FIG. 12 shows the result of superimposing the result on FIG.
- the processing efficiency is drastically reduced when L / D exceeds 60. This is because the rigidity of the tool becomes low due to the small diameter of the tool, so that the machining speed has to be reduced to prevent the tool from being damaged, and the cutting operation for chip discharge (non- This is because the processing time increases. Therefore, it can be seen that the range of L / D is preferably the following formula (13).
- the pressure loss h at the inlet / outlet of the fluid flowing in the turbulent state in the through hole 20b is ⁇ : Friction loss coefficient in the through hole 20b ⁇ : Fluid density u m : Flow rate is expressed by the following formula (14).
- FIG. 13 shows the relationship between L / D, cooling effect, and pressure loss when the flow rate Q ′ is constant.
- FIG. 13 is a graph in which the relationship between L / D and pressure loss is superimposed on FIG. 11 when the flow rate Q ′ is constant.
- the pressure loss follows the right axis. From this, it can be seen that the pressure loss suddenly increases when L / D exceeds 40.
- the cooling unit can be made more compact, or the cooling unit itself can generate heat. In order to suppress this, the pressure loss in the ball screw device 1 needs to be as small as possible.
- the axial direction of the through hole 20 can be determined from the equations (12) and (13).
- the ratio of the length L to the diameter D of the through hole 20b is preferably set in the range of the following formula (A).
- the ball screw device in which one through hole is formed in the nut is calculated.
- a plurality of through holes are arranged in the nut in the axial direction.
- L in the above calculation formula may be calculated as 4L (for example, when four through holes are arranged in parallel in the nut).
- FIG. 14A and 14B are cross-sectional views showing the configuration of the ball screw device according to the fourth embodiment.
- FIG. 14B is a modification of FIG.
- an O-ring 70 is provided between two nuts constituting the nut 20 (a first nut 20 ⁇ / b> A and a second nut 20 ⁇ / b> B, and a spacer 50).
- an opening of one of the through holes 20b and 20b is provided on the contact surfaces 21A and 21B of the first nut 20A and the second nut 20B with the spacer 50, respectively.
- Annular first accommodating portions 23A and 23B are formed so as to enclose, and an annular O-ring 70 surrounding the through holes 20b and 20b is accommodated in the first accommodating portions 23A and 23B.
- the O-ring 70 is provided between the first nut 20A and the second nut 20B and the spacer 50, so that the cooling medium does not leak from this portion. , Sealed state with spacer 50 If enough, O-ring 70 may be any of the first nut 20A and a second nut 20B, the first housing portion 23A, may not both 23B are always provided.
- an O-ring 70 installed between the spacer 50 and the nuts 20A and 20B is provided. You may install in 50 side. Specifically, one opening of the through hole 51 is formed on each of the one surface 50a of the spacer 50 facing the first nut 20A and the other surface 50b of the spacer 50 facing the second nut 20B. An annular second accommodating portion (concave portion) 52 is formed so as to surround the portion, and an O-ring 70 is installed in these second accommodating portions 52. If the sealed state of either the first nut 20A or the second nut 20B is sufficient, the O-ring 70 is provided on either one of the one surface 50a and the other surface 50b. In addition, the second accommodating portions 52 and 52 are not necessarily provided on both surfaces of the both surfaces 50a and 50b.
- the second accommodating portion 52 may be formed on the spacer 50 side. Can be reduced. (Fifth embodiment)
- a ball screw device according to a fifth embodiment will be described below with reference to the drawings.
- the ball screw device according to the present embodiment is a detailed description of the structure of the through hole 20b in the first embodiment described above. Therefore, the description of the same configuration with the same reference numeral as that of the first embodiment is omitted.
- FIG. 15A and 15B are cross-sectional views showing the configuration of the ball screw device according to the fifth embodiment.
- FIG. 15A is a cross-sectional view taken along the line 15a-15a in FIG. 1
- FIG. FIG. FIG. 16 is a perspective view showing the configuration of the insertion member of the ball screw device according to the fifth embodiment.
- an insertion member 60 extending in the length direction of the through hole 20b is disposed inside the through hole 20b.
- the cross-sectional shape of the insertion member 60 is formed so as to reduce the cross-sectional area of the flow path of the through hole 20b and to reduce the contact area with the inner peripheral surface of the through hole 20b as much as possible. Specifically, as shown in FIG.
- an insertion member 60 having a rhombic cross-sectional shape is disposed inside the through hole 20b.
- the insertion member 60 having a diamond-shaped cross-sectional shape extends in the length direction of the through hole 20b, and is in contact with the inner surface of the through hole 20b at four points in the cross section of the through hole 20b.
- the shape of the insertion member 60 extends in the length direction of the through hole 20b, reduces the cross-sectional area of the flow path of the through hole 20b, and has a contact area with the inner peripheral surface of the through hole 20b as much as possible. If it is small, it will not specifically limit. Moreover, the insertion member 60 may have a cross-sectional shape that divides the through hole 20b into a plurality of flow paths in the length direction thereof.
- FIG. 16A to 16F show specific shapes of the insertion member 60.
- FIG. The insertion member 60 shown in FIG. 16 (a) has a circular cross-sectional shape, extends in the length direction of the through hole 20b, and does not contact the inner surface of the through hole 20b in the cross section of the through hole 20b. It is arranged. Depending on the insertion member 60, a plurality of flow paths are not formed in the through hole 20b.
- the insertion member 60 shown in FIG. 16B has a circular cross-sectional shape, extends in the length direction of the through hole 20b, and contacts the inner surface of the through hole 20b at one point in the cross section of the through hole 20b. 20b is disposed inside. Depending on the insertion member 60, a plurality of flow paths are not formed in the through hole 20b.
- the insertion member 60 shown in FIG. 16 (c) has a rectangular cross-sectional shape, extends in the length direction of the through hole 20b, and contacts the inner surface of the through hole 20b at four points in the cross section of the through hole 20b. It arrange
- the insertion member 60 shown in FIG. 16 (d) has a triangular cross-sectional shape, extends in the length direction of the through hole 20b, and contacts the inner surface of the through hole 20b at three points in the cross section of the through hole 20b. It arrange
- the insertion member 60 shown in FIG. 16 (e) is the insertion member 60 having the cross-sectional shape shown in FIG. 15 (b), the cross-sectional shape is a rhombus shape, and extends in the length direction of the through-hole 20b. In the cross section of 20b, it is arrange
- the insertion member 60 shown in FIG. 16 (f) has a cross-sectional shape in which two circles are in contact with each other, extends in the length direction of the through hole 20b, and has two points on the inner surface of the through hole 20b in the cross section of the through hole 20b. It arrange
- the insertion member 60 shown in FIGS. 16 (a) to (f) forms a plurality of small cross-sectional flow paths in the through hole 20b. Therefore, there is an effect of increasing the flow rate of the coolant.
- the shape of the insertion member 60 is as much as possible on the inner peripheral surface of the through hole 20b.
- a shape having a small number of parts in contact with is preferable. That is, the insertion member 60 having the shape shown in FIG. 16D is preferable to the insertion member 60 having the shape shown in FIGS. 16C and 16E, and the insertion member 60 having the shape shown in FIG.
- the insertion member 60 having the shape shown in FIG. 16B is more preferable, and the insertion member 60 having the shape shown in FIG.
- the Reynolds number Re m that affects the cooling effect is u m : Flow velocity of the cooling medium v: Kinematic viscosity of the cooling medium a: The temperature conductivity of the cooling medium is expressed by the following formula (18).
- the flow velocity u m of the cooling medium is w: Flow rate of the cooling medium A: When the cross-sectional area of the through hole 20b is used, it is expressed by the following formula (19).
- the cross-sectional area A of the through hole 20b is represented by the following formula (20).
- the Reynolds number Re m represented by the equation (21) is higher when the diameter D of the through hole 20b is smaller when the flow rate w of the cooling medium is constant.
- it in reducing the diameter D of the through hole 20b, it must be in a range in which excessive pressure loss does not occur.
- heat exchange between the object to be cooled (nut 20) and the cooling medium in the through hole 20b is proportional to the contact area between the object to be cooled (nut 20) and the cooling medium in the through hole 20b.
- the insertion member 60 is disposed inside the through hole 20b, a through hole having a small diameter is formed by the arrangement of the insertion member 60, and the contact area is increased, so that Reynolds is increased. and realize the configuration to increase the number Re m.
- the diameter D of the through-hole 20b is replaced with the equivalent diameter De , and is represented by the following formula (22).
- the equivalent diameter D e in the case where the cross-sectional area of the flow path of the cooling fluid is considered a circle having the same cross-sectional area refers to the diameter of the circle.
- L wet indicates a length obtained by subtracting the length of the contact portion where the insertion member is in contact with the inner surface of the through hole from the circumferential length of the through hole. That is, in the installation mode of the insertion member shown in FIGS. 16 (a) to (f), L wet is equal to the circumferential length of the through hole in the mode of FIG.
- L wet is substantially equal to the circumferential length of the through hole
- L wet is determined from the circumferential length of the through hole as an insertion member. Is equal to the length obtained by subtracting the length of the four contact portions that are in contact with the inner surface of the through-hole.
- L wet is calculated based on the circumferential length of the through-hole. It is equal to the length obtained by subtracting the lengths of the three contact portions in contact with the inner surface of the through hole.
- the ball screw device 1 of the present embodiment since the insertion member 60 extending in the length direction of the through hole 20b is disposed in the through hole 20b, the sectional area of the flow path of the through hole 20b. The area where the cooling medium passing through the through hole 20b and the through hole are in contact with each other can be ensured. Therefore, it is possible to provide the ball screw device 1 that has as high a cooling effect as possible and does not cause excessive reduction in processing efficiency.
- the insertion member 60 has a cross-sectional shape that divides the through hole 20b into a plurality of flow paths in the length direction, thereby increasing an area where the cooling medium and the through hole are in contact with each other. Since a plurality of flow paths of the through-holes 20b having a reduced cross-sectional area are formed while being ensured, the flow rate of the coolant is increased, and an excessive reduction in processing efficiency can be more efficiently reduced.
- the configuration of the present embodiment may be applied to a ball screw device in which a through hole formed in the nut is formed in one ball screw device or a ball screw device in which a plurality of through holes are formed in the nut.
- a ball screw device 1 that prevents a higher cooling effect and excessive reduction in processing efficiency.
- FIG. 19 is a diagram for explaining the pressure loss associated with the change in the cross section of the flow path, and shows the case where the cross sectional area of the upstream flow path is smaller than the cross sectional area of the downstream flow path.
- FIG. 20 is a diagram for explaining the pressure loss accompanying the change in the channel cross section, and shows the case where the cross-sectional area of the upstream channel is larger than the cross-sectional area of the downstream channel.
- FIG. 21 is a diagram for explaining a change in flow velocity accompanying a change in the cross section of the flow path, and shows a case where four flow paths having the same cross section are connected in parallel with the fluid introduction pipe.
- FIG. 20 is a diagram for explaining the pressure loss accompanying the change in the channel cross section, and shows the case where the cross-sectional area of the upstream channel is larger than the cross-sectional area of the downstream channel.
- FIG. 21 is a diagram for explaining a change in flow velocity accompanying a change in the cross section of the flow path, and shows a case
- FIG. 22 is a figure explaining how to provide the inlet and outlet of the flow path in the ball screw of the present invention, and shows an example (a) having a high cooling effect and an example (b) having a low cooling effect.
- FIG. 17 is a view of the ball screw device in FIG.
- the ball screw device includes a nut having a spiral groove formed on the inner peripheral surface, a screw shaft having a spiral groove formed on the outer peripheral surface, a spiral groove of the nut, and a track formed by the spiral groove of the screw shaft. And a ball disposed between the grooves.
- the nut is formed with a plurality of (cooling) through holes that penetrate the nut in the axial direction. Adjacent through holes have the same or substantially the same cross-sectional shape and cross-sectional area.
- These through-holes are connected in series with a flow path forming member having the same or substantially the same shape and area of the cross section of the flow path at the axial end of the nut to form a flow path.
- a cooling medium introduction pipe and a cooling medium discharge pipe having the same or almost the same shape and area of the cross section of the flow path are connected in series to the inlet and the outlet of the flow path.
- the ball screw of this embodiment includes a nut 1, a screw shaft 2, a ball 3, a semicircular arc tube (flow path forming member) 4, and a coolant introduction pipe (cooling medium introduction).
- a pipe) 5 a coolant discharge pipe (cooling medium discharge pipe) 6, and connectors 81 to 84.
- the ball circulation member and the seal are omitted.
- a spiral groove 20 a is formed on the inner peripheral surface of the nut 20.
- a spiral groove 10 a is formed on the outer peripheral surface of the screw shaft 10.
- a ball 30 is disposed between the raceway grooves formed by the spiral groove 20 a of the nut 20 and the spiral groove 10 a of the screw shaft 10.
- a flange 24 is formed at one axial end of the nut 20.
- two through holes 20 b and 20 b penetrating in the axial direction are formed at positions facing each other in the diameter direction of the nut 20. At the end of the nut 20 on the flange 24 side, these through holes 20b and 20b are connected by a semicircular arc-shaped tube 4.
- One end of the tube 4 and the through hole 20 b are connected by a connector 81.
- the other end of the tube 4 and the through hole 20 b are connected by a connector 82.
- the flow path which consists of through-holes 20b and 20b and the tube 4 is formed.
- the coolant introduction pipe 5 and the coolant discharge pipe 6 connected to the entrance and exit of this flow path, Since the cross-section of the flow path (the cross-sectional shape and cross-sectional area of the flow path) is the same, the pressure loss of the coolant is reduced. Therefore, the cooling efficiency is increased and the burden on the coolant supply pump is reduced.
- the two through holes 20b and 20b are connected in series to the coolant introduction pipe 5 because the flow rate is kept constant.
- the cooling effect is enhanced as compared to the case where the flow path cross section becomes large at the branch point and the flow velocity is reduced, as in the case where they are connected in parallel. The operation of this embodiment will be described below.
- a change in the flow velocity accompanying a change in the cross-sectional area of the flow path will be described below.
- the flow breaks at the branch points to the respective flow paths.
- the area is four times that of each channel.
- the flow path cross-sectional area does not change. .
- the through holes 20b and 20b of the nut 20 are connected by the flow path forming member 4 to form a flow path, and the inlet 5a and the outlet 6a of the flow path are connected to the through holes.
- the two through holes 20b, 20b are connected in series, and the flow path cross section (shape and shape) from the flow path inlet 5a to the flow path 6a. Area) is the same.
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Abstract
Description
このようなねじ装置としては、前記冷却部(熱交換器)として、冷媒が循環する冷却パイプを前記送りナット内に配設したねじ装置が開示されている(例えば、特許文献1)。
具体的に、ねじ装置の温度上昇値θは、下記式(1)で表される。なお、下記式(1)において、tは経過時間、CMはねじ装置の熱容量、βはねじ装置からの単位時間、単位温度差あたりの放熱量、Qはナットから発生する単位時間当たりの熱量である。
Q=Tx60nx2π/1000=0.12πnT・・・・・・式(2)
特許文献1に示されているように、送りナットを単に冷却すると、式(1)のβが大きくなるが、上述のように同時にトルクが上昇してしまうと、式(2)よりQも大きくなってしまい、Q/βで得られる温度上昇値は大きくなる。従って、送りナットを単に冷却することにより、トータルとしての冷却効率は落ちてしまうという問題があった。
図7及び図8に示すように、ボールねじ装置1は、ねじ軸10と、ねじ軸10に対し、複数の転動体30を介して螺合するナット20とを有する。転動体30は、ねじ軸10のねじ溝10aとナット20のねじ溝20aとの間で予圧されている。
一方、発明者らは、ボールねじ装置のナットを冷却する場合、その冷却液を通す貫通孔の径によって冷却効果が大きく変化することを、非特許文献1に示されているNusseltの方法で推定し、実験によって上記冷却効果の変化について確認した。
しかし、高い冷却効果を得る目的で貫通孔の径を小さくすると、以下に示す2つの問題点が生じることがあった。
(1)貫通孔の加工が小径かつ長穴の加工となることから、加工効率が落ち、ボールねじ装置のコストアップに繋がる。
(2)冷却媒質を通すときの圧力損失が大きくなってしまう。
また、本発明者らは、ナットの軸方向に設けた貫通孔に冷却媒質を通すことで冷却を行なうボールねじにおいて、貫通孔の軸方向の長さLと貫通孔の径Dとの比L/Dを規定することにより、冷却効果をできるだけ高くし、過度な加工効率の低下や圧力損失の増加を招くことのないことを知見した。
前記ねじ軸のねじ溝と前記ナットのねじ溝との間には、予圧方向を引張り方向として2点接触状態で予圧を付与された前記複数の転動体が組み込まれていることを特徴としている。
前記貫通孔の軸方向の長さLと、前記貫通孔の径Dとの比(L/D)を下記式(A)としたことを特徴としている。
10≦L/D≦60・・・・・・・・・・・・・・・・・式(A)
また、本発明の他の実施形態に係るボールねじ装置は、ねじ軸と、複数の転動体を介して前記ねじ軸に螺合するナットと、該ナットを冷却する冷却部とを備え、
前記ねじ軸のねじ溝と前記ナットのねじ溝との間には、前記ナットを冷却したときに生じる前記ナットの収縮方向とは逆方向の予圧を付与した前記複数の転動体が組み込まれていることを特徴としている。
前記ナットは、間座を介して2つのナットを連結したダブルナットであって、該2つのナット及び前記間座には前記冷却部による冷却液が通る冷却液用貫通孔が形成され、前記間座の冷却液用貫通孔の両開口部にはOリングが設けられ、さらに前記ねじ軸のねじ溝と前記ナットのねじ溝との間には、前記ナットを冷却したときに生じる前記ナットの収縮方向とは逆方向の予圧を付与した前記複数の転動体が組み込まれていることを特徴としている。
本発明のある実施形態に係るボールねじ装置によれば、冷却部がナットに具備されると共に、前記ナットの予圧方式を引張り方向の2点接触予圧としたので、径方向への収縮は予圧荷重を高める方向に作用するが軸方向への収縮はこれを軽減するように作用するため、トータルの予圧荷重はほとんど増加しない。従って、冷却によってナットが収縮したときにも、動摩擦トルクが上昇しにくいボールねじ装置を提供することができる。すなわち、動摩擦トルクの上昇に伴うボールねじの温度上昇を防ぐことができ、結果として、ナットの冷却効果をできるだけ高くしたボールねじ装置を提供することができる。
また、本発明の他の実施形態に係るボールねじ装置によれば、ナットと間座との間における冷却媒質の漏れを防止することができる。
以下、本発明に係るボールねじ装置の第1の実施形態について図面を参照して説明する。図1は、本実施形態に係るボールねじ装置の構成を示す軸方向に沿う断面図である。
図1に示すように、本実施形態のボールねじ装置1は、ねじ軸10と、ナット20とを有する。ねじ軸10及びナット20は、複数の転動体30を介して螺合している。ナット20は、ねじ軸10の外径より大きい内径で筒状に形成されている。ナット20の内周面には、ねじ軸10の外周面に螺旋状に形成されたねじ溝10aに対向するようにねじ溝20aが形成されている。ねじ溝10aとねじ溝20aとによって形成された転動路において転動体30は転動可能とされている。
図2は、引張方向を予圧方向とした2点接触状態の予圧状態と収縮との関係を示す図である。
このため、本実施形態に係るボールねじ装置1では、引張方向の2点接触予圧をナット20に与えることにより、ナット20を冷却しても予圧トルクが増大することなく効率的にボールねじ装置1全体を冷却することができる。
(第2の実施形態)
図3は、第2の実施形態に係るボールねじ装置を示す図である。図3に示すように、本実施形態は、第1の実施形態が予圧方式として、オフセットリード予圧を採用したのに対し、ダブルナット予圧方式を採用している。
図4は、前述の第1の実施形態のボールねじ装置(図1参照)を実施例1のボールねじ装置として駆動し、駆動の途中でナットを冷却したときのナットの温度上昇値とトルクを同時に測定した結果を示すグラフである。
また、図5は、比較例1のボールねじ装置を駆動し、駆動の途中でナットを冷却したときのナットの温度上昇値とトルクを同時に測定した結果を示すグラフである。
ここで、比較例1のボールねじ装置の構成は、図6に示すように、ねじ溝10aとねじ溝20aとの間において、オーバーサイズボール予圧(4点接触予圧)された複数の転動体30が組み込まれている点が実施例1と異なる。
なお、図4及び図5において、ナットの温度が急激に低下したときが、冷却開始時である。
また、トルクの変化に着目すると、比較例1では、冷却前の約2倍までトルクが上昇している。これは、冷却によってナットが熱収縮をおこし、その熱収縮の方向が予圧方向と一致し、予圧荷重が高くなっているためである。この発熱が、冷却による放熱効果を薄め、結果的にトータルとしての冷却効果が小さくなっている。また、過大予圧を招き、結果としてボールねじ装置の寿命を低下させてしまう。
(第3の実施形態)
図9は、第3の実施形態に係るボールねじ装置の構成を示す側面図である。図9に示すように、本実施形態のボールねじ装置は、本実施形態のボールねじ装置1は、ねじ軸10と、ナット20とを有する。ねじ軸10及びナット20は、複数の転動体30を介して螺合している。ナット20は、ねじ軸10の外径より大きい内径で筒状に形成されている。ナット20の内周面には、ねじ軸10の外周面に螺旋状に形成されたねじ溝10aに対向するようにねじ溝20aが形成されている。ねじ溝10aとねじ溝20aとによって形成された転動路において転動体30は転動可能とされている。
α:熱伝達率
△θ:ねじ軸10と冷却媒質との温度差
F:ねじ軸10内の冷却媒質と接する面の面積
としたとき、下記式(3)で表される。
π:流体の熱伝導率
D:貫通孔20bの径
Num:ヌセルト数(Nusselt Number)
L:貫通孔20bの軸方向の長さ
としたとき、下記式(4)及び式(5)で表される。
Rem:レイノルズ数(Reynolds number)
Prm:プラントル数(Prandtl number)
としたとき、下記式(6)で表される。
um:冷却媒質の流速
v:冷却媒質の動粘度
a:冷却媒質の温度伝導率
としたとき、それぞれ下記式(7)及び式(8)で表される。
w:冷却媒質の流量
A:貫通孔20bの断面積
としたとき、下記式(9)で表される。
図11は、本実施形態において、表4のTP2(L/D=30)での温度上昇値を基準とした場合のその他のTPの温度上昇値を、図10の計算結果と併せて示したL/Dと冷却効果との関係を示すグラフである。図11に示すように、実験結果と計算結果は概ね良好な一致が認められ、上述の計算方法が実験的に確認できた。
(1)貫通孔20bの加工が小径の長穴加工となることから加工効率が落ち、ボールねじ装置のコストアップに繋がる。
(2)冷却媒質を通すときの圧力損失が大きくなってしまう。
ζ:貫通孔20b内の摩擦損失係数
ρ:流体の密度
um:流速
としたとき、下記式(14)で表される。
ボールねじ装置1を冷却する際には、ポンプや冷却機を有した冷却部によって冷却した冷却媒質をボールねじ装置に供給する必要があり、この冷却部をよりコンパクトにしたり、冷却部自身の発熱を抑えるためには、ボールねじ装置1内での圧力損失はできるだけ小さくする必要がある。
(第4の実施形態)
次に、第4の実施形態に係るボールねじ装置について図面を参照して以下に説明する。なお、本実施形態に係るボールねじ装置は、第1のナット20及び第2のナット30に対する間座50の設置態様が前述の第2の実施形態(図3参照)と異なるだけである。したがって、第2の実施形態と同じ符号を付した同様の構成については説明を省略する。
図14(a)に示すように、ナット20を構成する2つのナット(第1のナット20A及び第2のナット20Bと、間座50との間には、Oリング70が設けられている。具体的には、第1のナット20A及び第2のナット20Bのそれぞれの間座50との接触面21A,21Bに、貫通孔20b,20bの一方(接触面22A,22B側)の開口部を囲むように円環状の第1の収容部23A,23Bが形成されている。そして、第1の収容部23A,23Bには、貫通孔20b,20bを囲む円環状のOリング70が収容されている。このようにして第1のナット20A及び第2のナット20Bと、間座50との間にOリング70が設けられることにより、この部分から冷却媒質が漏れない構造となっている。なお、間座50との密封状態が十分であれば、Oリング70は、第1のナット20A及び第2のナット20Bのいずれかであってもよく、第1の収容部23A,23Bの両方が必ず設けられなくともよい。
(第5の実施形態)
次に、第5の実施形態に係るボールねじ装置について図面を参照して以下に説明する。なお、本実施形態に係るボールねじ装置は、前述した第1の実施形態において、貫通孔20bの構造について詳述するものである。したがって、第1の実施形態と同じ符号を付した同様の構成については説明を省略する。
図15(a)に示すように、本実施形態では、該貫通孔20bの長さ方向に延びる内挿部材60が貫通孔20bの内部に配設されている。この内挿部材60の断面形状は、貫通孔20bの流路の断面積を小さくし、かつ貫通孔20bの内周面との接触面積を可能な限り小さくするように形成されている。具体的には、図15(b)に示すように、菱形形状の断面形状を有する内挿部材60が貫通孔20bの内部に配設されている。この菱形形状の断面形状を有する内挿部材60は、貫通孔20bの長さ方向に延び、貫通孔20bの断面において貫通孔20bの内面に4点で接触している。
また、内挿部材60は、貫通孔20bをその長さ方向に複数の流路に分ける断面形状を有してもよい。
図16(a)に示す内挿部材60は、断面形状を円形とし、貫通孔20bの長さ方向に延び、貫通孔20bの断面において貫通孔20bの内面に接触しないように貫通孔20bの内部に配設されている。なお、この内挿部材60によっては貫通孔20b内に複数の流路は形成されない。
図16(c)に示す内挿部材60は、断面形状を矩形とし、貫通孔20bの長さ方向に延び、貫通孔20bの断面において貫通孔20bの内面に4点で接触して4つの流路を形成するように貫通孔20bの内部に配設されている。
図16(e)に示す内挿部材60は、図15(b)に示された断面形状の内挿部材60であ断面形状を菱形形状とし、貫通孔20bの長さ方向に延び、貫通孔20bの断面において貫通孔20bの内面に4点で接触して4つの流路を形成するように貫通孔20bの内部に配設されている。
図16(a)~(f)で示される内挿部材60のうち、図16(c)~(f)で示した内挿部材60は、貫通孔20b内に小さな断面の流路を複数形成するので、冷却液の流速を高める効果がある。ただし、循環装置(図示せず)の圧送容量が小さい場合には、内挿部材60の断面積を大きくしすぎることで、配管抵抗によって流速を上げることができなくなるため、前記循環装置の圧送容量に応じて内挿部材60の形状(断面形状及び貫通孔20bの内周面への接触面積)を決定する必要がある。
um:冷却媒質の流速
v:冷却媒質の動粘度
a:冷却媒質の温度伝導率
としたとき、下記式(18)で表される。
一方、被冷却物(ナット20)と、貫通孔20b内の冷却媒質との熱交換は、被冷却物(ナット20)と、貫通孔20b内の冷却媒質との接触面積に比例する。
この構成を用いることによって、上記貫通孔20bの径Dは、相当直径Deに置き換えられ、下記式(22)のように表される。ここで、下記式(22)において、相当直径Deは、冷却液の流路の断面積を同じ断面積の円を考えた場合の、その円の直径を指す。すなわち、内挿部材の断面積が大きければ大きい程、相当直径Deが小さくなり、この相当直径Deを上記式(21)のDに代入することによって求められるレイノルズ数Remが上がる(冷却効果が上がる)ことになる。なお、ナットに設けられる貫通孔径Dは変わらないので、加工効率は同等である。また、Adは流路の断面積である。また、Lwetは、貫通孔の円周長さから、内挿部材が貫通孔の内面に接している接触部分の長さを引いた長さを指す。すなわち、図16(a)~(f)で示される内挿部材の設置態様においては、図16(a)の態様でLwetは、貫通孔の円周長さに等しく、図16(b),(f)の態様でLwetは、貫通孔の円周長さにほぼ等しく、図16(c),(e)の態様でLwetは、貫通孔の円周長さから、内挿部材が貫通孔の内面に接している4箇所の接触部分の長さを引いた長さに等しく、図16(d)の態様でLwetは、貫通孔の円周長さから、内挿部材が貫通孔の内面に接している3箇所の接触部分の長さを引いた長さに等しい。
(第6の実施形態)
次に、第6の実施形態に係るボールねじ装置について図面を参照して以下に説明する。
以下、この実施形態について図面を参照して詳細に説明する。
この実施形態のボールねじは、図17に示すように、ナット1と、ねじ軸2と、ボール3と、半円弧状のチューブ(流路形成部材)4と、冷却液導入配管(冷却媒質導入配管)5と、冷却液排出配管(冷却媒質排出配管)6と、コネクタ81~84とを備えている。図17において、ボール循環部材及びシールは省略されている。
ナット20には、軸方向に貫通する2つの貫通孔20b,20bが、ナット20の直径方向で対向する位置に形成されている。ナット20のフランジ24側の端部で、これらの貫通孔20b,20bが半円弧状のチューブ4により接続されている。チューブ4の一端と貫通孔20bは、コネクタ81で連結されている。チューブ4の他端と貫通孔20bは、コネクタ82で連結されている。これにより、貫通孔20b,20bとチューブ4からなる流路が形成されている。
これにより、冷却液は、冷却液導入配管5→コネクタ83→ナット20の貫通孔20b→コネクタ81→チューブ4→コネクタ82→ナット20の貫通孔20b→コネクタ84→冷却液排出配管6の順に流れる。この冷却液の流れにおいて、直接的には貫通孔20b,20b内の冷却水の流れにより、ナット20が冷却される。
本実施形態の作用について、以下に説明する。
図19に示すように、上流側の流路201の断面積A1が下流側の流路202の断面積A2より小さい場合、損失ヘッドh’は、流路201の平均流速をV1、流路202の平均流速をV2、重力加速度をgとした時に、ベルヌーイの定理から下記の式(23)で表される。
ただし、ζ=(1-A1/A2)2である。
式(23)から、A1≒A2の時に損失ヘッドhが最小となることが分かる。
図20に示すように、上流側の流路201の断面積A1が下流側の流路202の断面積A2より大きい場合、損失ヘッドhは、流路201の平均流速をV1、流路202の平均流速をV2、重力加速度をgとした時にベルヌーイの定理から下記の式(24)式で表される。
ただし、ζ’=(A1/A2-1)2である。
式(24)から、A1≒A2の時に損失ヘッドh’が最小となることが分かる。
以上のことから、上流側の流路201の断面積A1と下流側の流路202の断面積A2を同じにすることで、圧力損失を低減できることが分かる。
なお、この圧力損失を小さくできる効果が特に発揮されるのは、油等の粘性が高いもの(動粘度係数1.585mm2/s以上)を流した場合と、乱流(レイノルズ数が3000以上)の場合である。
図21に示すように、断面の形状及び面積が同じ4つの流路を、断面の形状及び面積が同じ流体導入配管に対して並列に接続した場合、各流路への分岐点で流路断面積が各流路の4倍となる。これに対して、断面の形状及び面積が同じ4つの流路を直列に接続して、その一端に断面の形状及び面積が同じである流体導入配管を接続した場合、流路断面積は変化しない。
V=Q/A‥‥式(25)
式(25)から、冷却媒質の流速が大きいほど放熱量が大きくなって冷却効果は高くなるため、流路断面積が大きくなるほど逆に冷却効果は小さくなることが分かる。
以上のことから、複数の冷却流路を接続する際には、並列でなく直列で接続する方が高い冷却効果が得られることが分かる。
10 ねじ軸
20 ナット
30 転動体
40 冷却装置
Claims (4)
- ねじ軸と、複数の転動体を介して前記ねじ軸に螺合するナットと、該ナットを冷却する冷却部とを備え、
前記ねじ軸のねじ溝と前記ナットのねじ溝との間には、予圧方向を引張り方向として2点接触状態で予圧を付与された前記複数の転動体が組み込まれていることを特徴とするボールねじ装置。 - ねじ軸と、複数の転動体を介して前記ねじ軸に螺合するナットと、該ナットの軸方向に設けた貫通孔に冷却媒質を通して前記ナットの軸方向に設けた貫通孔に冷却媒質を通して前記ナットを冷却する冷却部とを備え、
前記貫通孔の軸方向の長さLと、前記貫通孔の径Dとの比(L/D)を下記式(A)としたことを特徴とするボールねじ装置。
10≦L/D≦60・・・・・・・・・・・・・・・・・式(A) - ねじ軸と、複数の転動体を介して前記ねじ軸に螺合するナットと、該ナットを冷却する冷却部とを備え、
前記ねじ軸のねじ溝と前記ナットのねじ溝との間には、前記ナットを冷却したときに生じる前記ナットの収縮方向とは逆方向の予圧を付与した前記複数の転動体が組み込まれていることを特徴とするボールねじ装置。 - ねじ軸と、複数の転動体を介して前記ねじ軸に螺合するナットと、該ナットを冷却する冷却部とを備え、
前記ナットは、間座を介して2つのナットを連結したダブルナットであって、該2つのナット及び前記間座には前記冷却部による冷却液が通る貫通孔が形成され、前記間座の貫通孔の開口部にはOリングが前記貫通孔を囲むように設けられ、さらに前記ねじ軸のねじ溝と前記ナットのねじ溝との間には、前記ナットを冷却したときに生じる前記ナットの収縮方向とは逆方向の予圧を付与した前記複数の転動体が組み込まれていることを特徴とするボールねじ装置。
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
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US13/058,124 US8752446B2 (en) | 2009-08-31 | 2010-08-25 | Ball screw device |
CN2010800022890A CN102124251A (zh) | 2009-08-31 | 2010-08-25 | 滚珠丝杠装置 |
EP10805567.4A EP2461072A4 (en) | 2009-08-31 | 2010-08-25 | BALL SCREW DEVICE |
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JP2009200082A JP5407671B2 (ja) | 2009-08-31 | 2009-08-31 | ボールねじ |
JP2009-200082 | 2009-08-31 | ||
JP2009248090A JP2010133556A (ja) | 2008-10-28 | 2009-10-28 | ボールねじ装置 |
JP2009-248090 | 2009-10-28 | ||
JP2010-090389 | 2010-04-09 | ||
JP2010090389A JP5732739B2 (ja) | 2010-04-09 | 2010-04-09 | ボールねじ装置 |
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WO2011024450A1 true WO2011024450A1 (ja) | 2011-03-03 |
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US (1) | US8752446B2 (ja) |
EP (1) | EP2461072A4 (ja) |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103389205A (zh) * | 2013-07-17 | 2013-11-13 | 西安交通大学 | 一种检测滚珠丝杠副加载状态下综合性能的装置 |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5733403B2 (ja) * | 2011-08-17 | 2015-06-10 | 日本精工株式会社 | ボールねじおよびその組み立て方法 |
US8960038B2 (en) * | 2011-10-01 | 2015-02-24 | Hiwin Technologies Corp. | Motion transmission module with a cooling device |
JPWO2013183298A1 (ja) * | 2012-06-07 | 2016-01-28 | 日本精工株式会社 | ボールねじ装置 |
WO2014115544A1 (ja) * | 2013-01-25 | 2014-07-31 | 日本精工株式会社 | ボールねじ装置 |
US9133922B2 (en) * | 2013-03-11 | 2015-09-15 | Hiwin Technologies Corp. | Load adjustable ball screw device |
CN105065597A (zh) * | 2015-07-28 | 2015-11-18 | 南京工艺装备制造有限公司 | 一种具有冷却结构的预紧型滚珠螺母 |
CN108150621B (zh) * | 2016-12-05 | 2020-06-16 | 上银科技股份有限公司 | 双螺帽冷却式滚珠螺杆 |
EP3392528B1 (en) * | 2017-04-21 | 2020-04-08 | Goodrich Actuation Systems Limited | Ballscrew lubrication |
EP3587864B1 (en) * | 2018-06-27 | 2021-05-05 | Goodrich Actuation Systems Limited | Ballnut lubrication |
CN110242719B (zh) * | 2019-05-06 | 2022-05-10 | 东田传动科技(嘉兴)有限公司 | 丝母机构及滚珠丝杠装置 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5263557A (en) | 1975-11-20 | 1977-05-26 | Setagaya Seisakusho Kk | Temperature control apparatus for feeding nut |
JPH06235446A (ja) * | 1993-02-08 | 1994-08-23 | Nippon Seiko Kk | ねじ装置における予圧機構 |
JP2002310258A (ja) | 2001-04-12 | 2002-10-23 | Shangyin Sci & Technol Co Ltd | 冷却流路を備えたボール・スクリュー |
JP2002372119A (ja) * | 2001-06-12 | 2002-12-26 | Nsk Ltd | ボールねじ装置 |
JP2007051688A (ja) * | 2005-08-18 | 2007-03-01 | Nsk Ltd | 直動装置 |
JP2010133556A (ja) * | 2008-10-28 | 2010-06-17 | Nsk Ltd | ボールねじ装置 |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3068713A (en) * | 1959-10-08 | 1962-12-18 | Nat Broach & Mach | Nut and screw drive device of the recirculating ball type |
JPS5869182U (ja) | 1981-11-02 | 1983-05-11 | アイシン精機株式会社 | 超低温流体用継手 |
JP3325679B2 (ja) * | 1993-12-10 | 2002-09-17 | 日本精工株式会社 | ボールねじのボール溝形状 |
JP3352024B2 (ja) | 1998-03-31 | 2002-12-03 | 光洋機械工業株式会社 | 送りねじの冷却装置 |
JP3721264B2 (ja) | 1998-07-15 | 2005-11-30 | 株式会社牧野フライス製作所 | 工作機械の送り軸冷却装置 |
CN1175195C (zh) | 2001-03-30 | 2004-11-10 | 上银科技股份有限公司 | 具有冷却通道的滚珠螺杆 |
US20020152822A1 (en) * | 2001-04-23 | 2002-10-24 | Yung-Tsai Chuo | Ball screw having a cooling channel |
JP4729821B2 (ja) | 2001-08-03 | 2011-07-20 | 日本精工株式会社 | ボールねじ |
US6817260B2 (en) | 2001-11-09 | 2004-11-16 | Hiwin Technologies Corporation | Ball screw with cooling means |
JP2005030521A (ja) | 2003-07-09 | 2005-02-03 | Osaka Gas Co Ltd | コルゲート管とコルゲート管の配管工法とコルゲート管の改修工法 |
US7363835B2 (en) * | 2003-09-10 | 2008-04-29 | Nsk Ltd. | Ball screw apparatus |
CN1871460A (zh) | 2003-10-20 | 2006-11-29 | Thk株式会社 | 滚柱丝杠 |
ES2255427B2 (es) * | 2004-10-22 | 2007-08-16 | Shuton, S.A. | Husillo a bolas precargado perfeccionado con rosca perfilada con forma de arco gotico-ojival multiple. |
JP2006329228A (ja) * | 2005-05-23 | 2006-12-07 | Nsk Ltd | 直動装置 |
-
2010
- 2010-08-25 EP EP10805567.4A patent/EP2461072A4/en not_active Withdrawn
- 2010-08-25 CN CN2010800022890A patent/CN102124251A/zh active Pending
- 2010-08-25 WO PCT/JP2010/005236 patent/WO2011024450A1/ja active Application Filing
- 2010-08-25 US US13/058,124 patent/US8752446B2/en not_active Expired - Fee Related
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5263557A (en) | 1975-11-20 | 1977-05-26 | Setagaya Seisakusho Kk | Temperature control apparatus for feeding nut |
JPH06235446A (ja) * | 1993-02-08 | 1994-08-23 | Nippon Seiko Kk | ねじ装置における予圧機構 |
JP2002310258A (ja) | 2001-04-12 | 2002-10-23 | Shangyin Sci & Technol Co Ltd | 冷却流路を備えたボール・スクリュー |
JP2002372119A (ja) * | 2001-06-12 | 2002-12-26 | Nsk Ltd | ボールねじ装置 |
JP2007051688A (ja) * | 2005-08-18 | 2007-03-01 | Nsk Ltd | 直動装置 |
JP2010133556A (ja) * | 2008-10-28 | 2010-06-17 | Nsk Ltd | ボールねじ装置 |
Non-Patent Citations (2)
Title |
---|
JUNJI CHIGIRA: "Heat Transfer Calculation Method", 1981, KOGAKUTOSHO, INC, pages: 18 - 97 |
See also references of EP2461072A4 * |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN103389205A (zh) * | 2013-07-17 | 2013-11-13 | 西安交通大学 | 一种检测滚珠丝杠副加载状态下综合性能的装置 |
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US8752446B2 (en) | 2014-06-17 |
EP2461072A4 (en) | 2016-12-14 |
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