JPH0413084Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a grinding wheel shaft drive mechanism of a grinding machine, in particular, a pulley is attached to the rear end of the grinding wheel shaft, and the grinding wheel shaft is driven by a motor via a belt and a pulley. This invention relates to a grinding wheel shaft pulley support mechanism for a grinding machine.

(Prior art) In this type of grinding machine, a transmission belt is placed between a pulley attached to the rear end of the grinding wheel shaft (grinding wheel shaft pulley) and a pulley attached to the output shaft of the grinding wheel shaft drive motor. Although the shaft is rotated, conventional grinding wheel shaft pulleys are either directly fixed to the grinding wheel shaft or are made of an outer member (grinding wheel head body) that surrounds the grinding wheel shaft.
The structure was such that it was supported on the outer circumference of the rear end via a rolling bearing and was connected to the grindstone shaft with bolts or the like. In this case, the grindstone shaft is usually supported by a sliding bearing or the like built into the inner circumference of the grindstone head body.

(Problem to be solved by the invention) In the conventional grinding wheel shaft drive mechanism described above, belt tension is applied from the grinding wheel shaft pulley to the grinding wheel shaft via the steel balls of the rolling bearing, and this is applied as an external force of bending or twisting of the grinding wheel shaft. This causes a decrease in grinding accuracy. In addition, vibrations generated in the motor, transmission belt, or rolling bearing are easily transmitted to the grinding wheel shaft, which has the disadvantage of causing chatter and reducing the degree of grinding of the workpiece. In particular, when the rolling bearing that supports the pulley wears out, the vibration of the grindstone shaft increases, resulting in severe deterioration of accuracy.

(Means for Solving the Problems) A support mechanism for a grinding wheel shaft pulley of a grinding machine according to the present invention connects the grinding wheel shaft pulley to the grinding wheel shaft at its end, and also includes a rear outer periphery of a grinding wheel head body that surrounds the grinding wheel shaft. A hydrostatic pressure bearing portion for pivotally supporting the grinding wheel shaft pulley is formed on the surface, and a hydrostatic oil supply passage and a discharge passage communicating with the static pressure bearing portion are formed in the grinding wheel head main body, and the hydrostatic oil is supplied to the grinding wheel head. The water is supplied to and discharged from the static pressure bearing section through the main body.
In practice, the grinding wheel shaft pulley is connected to the grinding wheel shaft via a suitable intermediate member made of a material that does not easily transmit vibrations, such as a flexible intermediate member such as an elastic material, or an intermediate member such as a casting having a vibration damping effect. . The vibration damping effect of castings is well known, for example, as described in the Foundry Handbook (revised 3rd edition) published by the Japan Foundry Association, and it is known that the damping ability is five times greater than that of steel. In the present invention, even if the belt itself experiences vibration due to high-speed rotation, it does not affect the grinding wheel head body due to the static pressure bearing, and the flexible vibration interposed between the pulley and the end of the grinding wheel shaft The influence on the grinding wheel shaft side is also alleviated by the intermediate member and the like. When the grinding wheel shaft pulley is supported by a rolling bearing, the vibration caused by the rolling bearing is added to the vibration caused by the rotation of the belt itself and is applied to the grinding wheel shaft pulley, but this does not occur with this invention, and the pulley Vibration is reduced compared to before.

(Example) Next, an example of the present invention will be described with reference to the drawings and compared with a conventional example.

First, to briefly explain the support mechanism of the conventional grinding wheel shaft pulley shown in FIG. The bearing part 3 is rotatably supported by an oil film made of pressurized oil introduced into the inner circumferential surface of the bearing part 3 through non-metallic contact. A rolling bearing 4 is mounted on the outer periphery of the rear end of the grinding wheel head main body 2, and the grinding wheel shaft pulley 5 is pivotally supported by this rolling bearing 4. One end of the grindstone shaft pulley 5 is fixed to an end plate 6 keyed to the rear end of the grindstone shaft 1 with a bolt. A motor (not shown) rotates the grindstone shaft pulley 5 via the belt 7, and rotational force is transmitted from the pulley 5 to the grindstone shaft 1 via the end plate 6. In this conventional example,
The vibrations of the motor, belt 7, and rolling bearing 4 are transmitted from the grinding wheel head main body 2 to the grinding wheel shaft 1 via the plain bearing part 3, and to the grinding wheel shaft 1 via the pulley 5 and end plate 6, and the belt tension is transmitted to the grinding wheel shaft 1 via the pulley 5 and end plate 6. This acts as a bending external force on the grindstone head main body 2 and the grindstone shaft 1 via the rolling bearing 4, resulting in deterioration of accuracy.

FIG. 1 is a longitudinal sectional view of a grindstone shaft pulley support mechanism according to an embodiment of the present invention. A hollow whetstone head body 2 surrounds the whetstone shaft 1 in a non-contact state and extends to near the rear end with a distance 16 from the whetstone shaft 1. A grindstone shaft pulley 5 is pivotally supported via a pressure bearing portion. The grinding wheel shaft 1 is supported by a sliding bearing 3 provided on the inner circumference of the grinding wheel head body 2, and is rotationally supported by a film of pressurized oil introduced into the inner circumferential surface of the sliding bearing 3 through non-metallic contact. There is. A coupling ring 8 having a flange portion 8a is fixed to the rear end of the grindstone shaft 1. A plurality of bolt insertion holes are formed in the flange portion 8a, and an annular elastic body 10 that is difficult to transmit vibration and serves as an intermediate member is embedded in each bolt insertion hole, and a bolt 12 is passed through the hole of the elastic body 10. By screwing into the end of the grinding wheel shaft pulley 5, the elastic body 10 is tightened by the bolt head and the end of the pulley, and the coupling ring 8 and the grinding wheel shaft pulley 5 are tightened to some extent through the elastic body. Connected flexibly. Furthermore, there is a grinding wheel 11 at the tip of the grinding wheel shaft.
is attached, and a whetstone cover (not shown) is attached to the tip of the whetstone head body.

2 and 3 are detailed sectional views of the hydrostatic bearing portion formed on the outer periphery of the grinding wheel head main body 2. Particularly, FIG. 2 is an enlarged vertical sectional view of section A in FIG. The figure is a cross-sectional view of the hydrostatic bearing section. A plurality of static pressure pocket grooves 13 with a depth of about 2 to 3 mm extending in the axial direction are formed on the outer circumferential surface of the grinding wheel head body 2, and a gap of about 30 μm is formed between both axial ends of the grooves and the grinding wheel shaft pulley 5. 〓It has been blocked for a while. This static pressure pocket groove 13 communicates with a static pressure oil supply passage 14 formed in the grinding wheel head main body 2 via a constricted portion 18 (FIGS. 2 and 3). Further, each pocket groove 13 is supplied with pressure oil whose pressure is regulated individually through a dedicated passage 14. A hydrostatic oil discharge passage 15 is further formed in the grinding wheel head main body 2, and the discharge passage 15 is connected to an annular gap 16 between the grinding wheel shaft 1 and the grinding wheel head main body 2.
is connected to. Note that the center position of the static pressure pocket groove 13 in the length direction is formed to coincide with the center position of the belt 7 hung on the grindstone shaft pulley 5.

With this configuration, the driving force of a motor (not shown) is transmitted from the belt 7 to the grindstone shaft 1 via the grindstone shaft pulley 5, the elastic body 10, and the coupling ring 8. At the same time, high-pressure static oil enters the static pressure pocket groove 13 from the supply port of the grinding wheel head main body 2 through the supply passage 14 and the constriction part 18, and from the groove flows from the gap 21 between the pulley 5 and the grinding wheel head main body 2 to the It flows out in the direction of the arrow in FIG. 1 and is discharged through the discharge passage 15. To prevent pressure oil from leaking to the outside, an O-ring 19 is provided between the inner circumference of the grinding wheel shaft pulley 5 and the coupling ring 8, and an oil seal 20 is provided between the outer circumference of the other end of the pulley 5 and the grinding wheel head body 2. provided. As another embodiment of the present invention, the coupling 8 between the pulley 5 and the grinding wheel shaft 1 may be formed of a cast metal that is difficult to transmit vibrations.

When tension from the belt 7 is applied to the grinding wheel shaft pulley 5, the gap 21 of the hydrostatic bearing section slightly changes vertically and horizontally to cancel out the tension, providing oil film rigidity and supporting the pulley 5 through non-metallic contact. Ru. The vibrations transmitted from the belt 7 to the grindstone shaft 1 are reduced by the vibration damping effect of the oil film pressure and by the member made of a material that is difficult to transmit vibrations and is interposed between the pulley 5 and the end of the grindstone shaft. Further, since the pressure of the pressure oil supplied to each pocket groove 13 is adjusted individually, the grinding wheel shaft pulley 5 is supported concentrically with the grinding wheel shaft head with the same membrane pressure all around without being biased to one side.

(Effect of the invention) As explained above, according to the invention, the grinding wheel shaft 1
is supported by a static pressure bearing on the outer periphery of the grinding wheel head via a pulley and an intermediate member that does not easily transmit vibrations, such as a flexible intermediate member or casting, so there is no vibration caused by conventional rolling bearings, and the motor and The vibrations of the belt are absorbed by the fluid film (oil film) of the intermediate member and the hydrostatic bearing, and transmission to the grindstone shaft is reduced. Since the hydrostatic bearing is provided with a throttle part, the hydraulic pressure is balanced, resulting in highly accurate and stable rotation of the grindstone shaft.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a grinding wheel shaft pulley support mechanism according to an embodiment of the present invention, Fig. 2 is an enlarged longitudinal cross-sectional view of section A in Fig. 1, and Fig. 3 is a cross-sectional view of a hydrostatic bearing according to the present invention. The plan view and FIG. 4 are longitudinal sectional views of a conventional grindstone shaft pulley support mechanism. 1... Grinding wheel shaft, 2... Grinding wheel head body, 5... Grinding wheel shaft pulley, 7... Belt, 8... Cutoff ring,
10...Elastic body, 13...Static pressure pocket groove, 14
... Supply passage, 15... Discharge passage, 18... Throttle section.

Claims (1)

[Scope of utility model registration request] The grindstone shaft pulley is connected to the grindstone shaft at its end via a member made of a material that does not easily transmit vibrations, and the grindstone shaft pulley is pivotally supported on the outer periphery of a grindstone head body that surrounds the grindstone shaft in a non-contact state. A support mechanism for a grindstone shaft pulley, characterized in that a hydrostatic pressure bearing is formed, and a hydrostatic oil supply passage and a discharge passage communicating with the hydrostatic pressure bearing are formed in the grindstone head main body.