JPH0532828U - Main shaft bearing preloading device for machine tools - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate backlash in the thrust direction by improving the rigidity of the main shaft bearing, and to eliminate backlash in the radial direction between the housing and the bearing. [Configuration] To interposed a hydraulic cylinder device 3 between the outer ring 1 ₁ of opposing pairs in order to support the main shaft 2 at both ends of the machine tool arranged tapered roller bearing 1. The hydraulic cylinder device 3 and the hydraulic pressure source 4 are connected by a hydraulic pipe 7 via a pressure reducing valve 8. The outer ring 1 ₁ of one of the tapered roller bearings 1 on the fixed side has a collar 1 _{2 on} the outer ring 1 _1.
To provide. A flow rate adjusting valve 9 with a check valve is provided between the pressure reducing valve 8 and the hydraulic cylinder device 3 in the middle of the fixed hydraulic pipe 7.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for applying a preload to a bearing for supporting a spindle of a machine tool, which is required to have high rigidity and high precision, such as a lathe used for machining the tip of a steel pipe.

[0002]

[Prior Art]

 For example, in a screw turning lathe, if there is rattling or whirling of the spindle during cutting, the surface roughness of the cut surface of the workpiece becomes rough, and the product quality will deteriorate even if the dimensional accuracy is within the allowable range. . Therefore, in order to eliminate play in the main shaft bearings of machine tools, facing tapered roller bearings are used for the main shafts, the inner ring spacers of these tapered roller bearings are ground to adjust the bearing clearance, and then the nut is thrust in the thrust direction. The inner ring of the bearing was fixed by applying a preload by tightening it to eliminate the clearance and improve the rotation accuracy of the main shaft.

However, during use, the nut may loosen or wear and the preload may not work. In that case, disassemble the machine to scrape the inner ring spacer, or I was taking measures such as tightening the nuts.

Therefore, for example, JP-A-51-29648, JP-A-51-94046, JP-A-58-187616, JP-A-61-30721, and JP-A-62-126616. Various devices for applying a preload have been proposed conventionally, such as the official gazette and Japanese Utility Model Laid-Open No. 62-130218.

[0005]

[Problems to be solved by the device]

 However, since the main body housing itself has a portion that serves as a fluid pressure holding container, it is difficult to process and attach the main body housing as proposed in the publication. Further, in the one proposed in the publication mentioned below, since the housing itself is a container for holding fluid pressure and also an actuator accompanied by elastic deformation, it is difficult to manage the preload. Further, in the publication proposed in the above-mentioned publication, since the piston pushes the spindle itself only in one direction, and the thrust force does not act on one side of the angular contact bearing, the spindle plays. Also, if the pistons are not evenly arranged on the circumference, a moment may be applied to the bearing, which adversely affects the bearing.

An object of the present invention is to provide a preload applying device capable of solving the problems of the above-described conventional preload applying device.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a spindle bearing preloading device for a machine tool according to the present invention forms a pair of tapered roller bearings which are opposed to each other to support both ends of a spindle of a machine tool. A hydraulic cylinder device is provided between the outer rings to connect each of these hydraulic cylinder devices and the hydraulic source with hydraulic piping via a pressure reducing valve, and one of the fixed side paired tapered roller bearings is connected. The outer ring has a collar, and a flow control valve with a check valve is provided between the pressure reducing valve and the hydraulic cylinder device in the middle of the fixed hydraulic pipe.

[0008]

[Action]

 In the spindle bearing preloading device for machine tools configured as described above, if a constant hydraulic pressure is applied to each hydraulic cylinder device, a constant preload acts on the bearings, increasing the rigidity of the bearings and increasing the thrust direction. Play is eliminated. In addition, since the outer ring expands in the radial direction by the preload, the radial play between the housing and the bearing is also eliminated.

Further, since the outer ring is fixed by providing the collar on one outer ring of the bearing provided on the fixed side, the pressure does not escape when the hydraulic cylinder device applies a preload to the bearing. .

Further, since the check valve is provided with the flow rate adjusting valve between the pressure reducing valve and the hydraulic cylinder device in the middle of the fixed-side hydraulic piping, an excessive force momentarily acts on the spindle during cutting. Even if the pressure in the fixed-side hydraulic cylinder device rises, the opening of the flow rate adjusting valve is reduced to create resistance against oil spilling, which prevents oil spilling.

[0011]

【Example】

 Hereinafter, the present invention will be described based on an embodiment shown in the accompanying drawings. FIG. 1 is an explanatory view of a main part of the device of the present invention, FIG. 2A is an overall schematic view of the device of the present invention, and FIG. 2B is an explanatory view of a hydraulic cylinder device part.

In the drawings, reference numeral 1 denotes, for example, a tapered roller bearing which supports both ends of a main shaft 2 of a machine tool on a fixed side (right side in FIG. 2A) and a free side (left side in FIG. 2A), respectively. Two of them are arranged to face each other and form a pair. 3 is a hydraulic cylinder device provided between the outer ring 1 ₁ of the tapered roller bearing 1 forming these pairs, oil from the oil pressure source 4 to these hydraulic cylinder device 3 holds these tapered roller bearing 1 It is performed from the oil supply hole 6 opened in the main body housing 5. A pressure reducing valve 8 is provided in the middle of the hydraulic pipe 7 for supplying pressure oil from the hydraulic pressure source 4 to the hydraulic cylinder device 3 so that the pressure of the pressure oil supplied to the hydraulic cylinder device 3 can be adjusted. Further, a flow control valve 9 with a check valve is further provided between the pressure reducing valve 8 in the fixed hydraulic pipe 7 and the hydraulic cylinder device 3.

Further, the flange 1 ₂ is provided on one of the outer ring 1 _one of the tapered roller bearing 1 pairs of fixed side, with stop plate 10 to the flange 1 _2, press and hold the clamping form the body housing 5 is doing. Incidentally, 11 is a hydraulic cylinder device 3 of the detent key in FIG. 12 is a inner ring spacer installed between the inner ring 1 ₃ circular cone roller bearing 1 paired, hydraulic Cylinders device 3 outer ring built upon to avoid slip out from between 1 _1, that have provided a protrusion in the center.

[0014] That is, the spindle bearing preload application device according to the present invention are configured as described above, the fixed side of the machine tools of the spindle 2, is provided between the outer race 1 ₁ of the tapered roller bearing 1 which forms the free side of the pair hydraulic The cylinder device 3 can uniformly apply a preload to the opposed tapered roller bearings 1. In the present invention, since the flange 1 ₂ is provided on the outer race 1 ₁ of one of the tapered roller bearing 1 of the fixed outer ring 1 ₁ is fixed to the main body housing 5 by the flange 1 _2, the hydraulic cylinder device 3 Even when a preload is applied to the tapered roller bearing 1, the fixed side tapered roller bearing 1 is fixed in the thrust direction, and the support rigidity of the main shaft 2 is increased. Further, since the outer ring 1 ₁ by the action of the preload will expand in the radial direction, the radial direction of the gap, can be eliminated also play.

By the way, when an excessive force is momentarily applied to the spindle 2 during work, the pressure in the hydraulic cylinder device 3 on the fixed side instantaneously rises, and the pressure oil escapes through the pressure reducing valve 8, There is a possibility that the spindle will be displaced and the machining accuracy will be impaired. However, in the present invention, in such a case, it is possible to prevent oil leakage by providing resistance against oil leakage by narrowing the opening of the flow control valve with check valve 9. When refueling, the check valve opens, so there is no resistance.

In the bearing support configured as in this embodiment, the free side tapered roller bearing 1 is movable in the axial direction in order to absorb the expansion due to the expansion of heat, but there is a looseness during machining. Since high-precision cutting cannot be done without removing it, during use, thermal expansion occurs at the beginning of operation.Therefore, the free side does not apply preload by the device of the present invention and detects the spindle temperature after operation. When the temperature becomes stable, pressure oil may be supplied to the free-side hydraulic cylinder device 3 to apply a preload. In this way, the clearance inside the tapered roller bearing 1 and the clearance between the main body housing 5 and the tapered roller bearing 1 are eliminated, and high precision cutting becomes possible.

In order to prevent fatal damage to the machine when the pressure oil supply is interrupted due to some trouble, it is desirable to provide an interlock circuit for stopping the main shaft in such a case. Also, it is desirable to detect the spindle speed, lubricating oil temperature, housing body temperature, etc. on both the fixed side and the free side, and apply the optimum preload to each condition.

[0018]

[Effect of the device]

 As described above, according to the present invention, the preload adjustment can be performed after the machine tool is assembled and also during operation, and there is no pressure holding container in the main body housing, and the spacer is a hydraulic cylinder device. Therefore, the configuration is simple. Further, according to the present invention, the structure is rigid even against an external force that acts suddenly, and the pressure can be adjusted on the fixed side and the free side.

[Brief description of drawings]

FIG. 1 is an explanatory view of the main part of the device of the present invention.

2 (a) is an overall schematic view of the device of the present invention, and FIG. 2 (b) is an explanatory view of a hydraulic cylinder device part.

[Explanation of symbols]

1 tapered roller bearing 1 ₁ outer ring 1 ₂ collar 2 main shaft 3 hydraulic cylinder device 4 hydraulic power source 7 hydraulic piping 8 pressure reducing valve 9 flow control valve with check valve

Claims (1)

[Scope of utility model registration request] 1. A hydraulic cylinder device is provided between each pair of outer rings of a pair of tapered roller bearings, which are opposed to each other to support both ends of a spindle of a machine tool, and each of these hydraulic cylinder devices is provided. The hydraulic pressure source and the hydraulic pressure source are connected to each other via hydraulic pressure reducing pipes, and a flange is provided on one outer ring of one of the fixed side paired tapered roller bearings, and a pressure reducing valve in the middle of the fixed side hydraulic pipe is connected. A spindle bearing preload applying device for a machine tool, characterized in that a flow rate adjusting valve with a check valve is interposed between hydraulic cylinder devices.