JPS59166404A - Balancer of machine tool - Google Patents

Abstract

PURPOSE:To easily make assembly work even in a limited space for assembling by maintaining the fitting load of a spring member constant by means of a movable member regardless of elevating/lowering motion of an elevating/lowering body. CONSTITUTION:An elevating/lowering body 14 is suspended by means of a pair of chains 21, 21, which is bridged by means of sprocket wheels 23, 23. Said wheels 23 are fixed on both ends of a rotary axis 31 which forms a male screw 32, into which a cylindrical nut 33 is screwed. An annular retainer 35 and a sleeve 36 are united in one body with the nut 33, while a spring member 38 is assembled, being given a predetermined fitting load, between the retainer 35 and a flange 37a of the cylindrical member 37. Fitting load of the spring member 38 given to the nut 33 through the sleeve 36 is converted into a rotational power of the rotary axis 31 by means of screwing action of the male screw 32, and this power balances with the weight of the elevating/lowering body 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a balance device useful for smoothly raising and lowering an elevating body such as a spindle head assembled in a machine tool using a small drive device.

(1) Conventionally, this type of balance device is a device in which the +1 spindle head is suspended by a piston rod of a hydraulic or pneumatic cylinder, and the pressure inside the cylinder is controlled according to the movement of the spindle head. (2) A device in which a weight is connected to a chain that suspends the spindle head via a pulley to balance the weight of the weight and the spindle head. (3) The spindle is attached to one end of the swing link. A device has been developed that balances the weight of the spindle head and the spindle head by connecting the head and the other end with a weight.
) has the drawback of requiring a large pump unit and poor response during operation. Further, in the above device (2), a large assembly for the weight requires space, and therefore there is a drawback that the applicable mechanical configuration is extremely limited. Furthermore, in the above device (3), the way the load is applied differs depending on the placement of the weight, and a large assembly for the weight requires space, so that the applicable mechanical configuration is extremely limited to (2). There is a drawback that it is limited.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to operatively connect a spring member to which a predetermined mounting load is applied to an elevating object such as a spindle head, and to balance the elevating operation of the elevating object by the spring member. The purpose of this invention is to provide a balancing device that can be easily applied even in spaces with limited assembly in various mechanical configurations.

In order to achieve the above object, the present invention provides a machine tool in which an elevating body such as a spindle head is attached to one side of a base set upright on a bed, in which a chain for suspending the elevating body is attached to the base body. A sprocket wheel that is mounted on a side wall and winds up or rewinds the chain in response to the lifting and lowering operations of the lifting body is fixed to one end of a rotating shaft that is pivotally supported on the base, and is adapted to support the weight of the lifting body. The same can be achieved by assembling a spring member to which a mounting load is applied to the rotating shaft, and engaging the movable member that is held at a predetermined position on the rotating shaft in conjunction with the drive mechanism of the elevating body to the spring member. The present invention is intended to provide a balance device (3) that maintains the mounting load of a spring member constant.

In a balance device having such a structure, the spring member is particularly attached to a rotating shaft supported on a base body so that the weight of the elevating body is supported by the mounting load thereof, and the spring member +
The second feature of the mechanism is that the mounting load of A can be kept constant by the movable member regardless of the lifting and lowering operation of the lifting body, and this allows for limited assembly of applicable machine configurations. It can provide a small and lightweight balance device that takes up little space and is easily assembled.

An embodiment of the present invention will be described below with reference to the drawings.
The machine tool shown in FIG. 1 includes a column 12 erected on one side of a head 11, a base (saddle) 13 attached to the upper shoulder of the column 12 so as to be movable in the front and back direction, and a base 13.
The main shaft head 14 is attached to the left side of the figure so as to be slidable in the vertical direction, and an electric motor 15 is attached to the upper part of the base body 13 to move the elevator 14 up and down.

A spindle 16 is attached to the lower end of the elevating body 14, and a slide table 17 screwed onto a screw shaft 19 driven by electric motors 1 (4) 8 is slidable in the left and right directions on the upper surface of the bed 11. It is assembled into.

In the machine tool having such a configuration, the elevating body 14 includes a pair of chains 21 and 21 constituting a balance device according to the present invention.
is suspended by. (See Figures 2 and 3) Each chain 21 is mounted on sprocket wheels 22 and 23 that are pivotally supported on both the front and rear sides of the base body 13, and the lower sprocket wheels 23 actuate the lifting body 14. It is designed to be wound up or rewound depending on the situation. The end of each chain 21 is connected 24a to a winding roll 24 pivotally supported on both front and rear sides of the base body 13. A helical spring 25 is attached to the center of each take-up roll 24, with one end fixed to the support shaft 26 and the other end fixed to the inner circumferential wall of the take-up roll 24.

As shown in FIG. 3, each sprocket wheel 23 is fixed by a key (5) 31a to both ends of a rotating shaft 31 which is horizontally supported on both side walls 13a, 13a of the base body 13. The rotary shaft 31 has a male thread 32 formed at its substantially central portion, and a cylindrical nut 33 is screwed onto the male thread 32 via an unillustrated ball to constitute a well-known ball screw device. An annular retainer 35 and a sleeve 36 are integrally connected to this cylindrical nut 33 by bolts 34. Annular retainer 3
5 is attached to the inner end of a cylindrical member 37 fitted to the rotating shaft 31 so as to be movable in the axial direction, and the annular retainer 35
A spring member 38 consisting of a large number of disc springs is assembled between the flange 378 of the cylindrical member 37 and a predetermined mounting load. The sleeve 36 is rotatably fitted onto the rotating shaft 31, and spline-engaged with the cylindrical body 41 at a spline portion 36a formed on its outer periphery. The cylindrical body 41 is connected to the side wall 1 of the base body 13 via a pair of bearings 41a and 4.1a.
The worm wheel 42 is rotatably supported by the worm wheel 3a, and a worm wheel 42 is fixed to the inner end thereof by a key 423. As shown in FIG. 4, the worm 43 meshed with the worm wheel 42 is integrally formed with a worm shaft 44 that is vertically supported on the inner wall 13b of the base body 13 (6). A sprocket wheel 45 fixed to the upper end of the worm shaft 44 is connected by a chain 48 to a drive sprocket wheel 46 that rotates integrally with a drive shaft 47 of the electric motor 15 assembled on the base j3. Note that a feed screw 47a formed in the lower part of the drive shaft 47 is screwed into the NAND portion 14a (see FIG. 3) of the elevating body 14, and the rotation of the drive shaft 47 causes the elevating body 14 to rise or It's supposed to go down.

In the balance device of this embodiment configured as described above, when the elevating body 14 is located at its lowering end and the electric motor 15 is stopped, the cylindrical body 41 and the sleeve 36 that is spline-engaged therewith are connected to the worm wheel. 42 and the worm 43 are engaged to prevent rotation. Therefore, the spring member 3 is attached to the nut 33 through the sleeve 36.
The mounting load of 8 is applied to the rotating shaft 3 by the screw action of the male screw 32.
This rotational force is balanced by the weight (7) of the elevating body 14 applied to the rotating shaft 31 via the chain 21. Further, when the elevating body 14 rises due to normal rotation of the electric motor 15, the rotating shaft 31 is rotated, and as a result, the nut 33 and the annular retainer 35 are integrally moved in the axial direction by the action of the male screw 32 on the rotating shaft 31. , and attempts to change the mounting load of the spring member 38.

However, due to the rotation of the electric motor 15, the worm shaft 44 is driven by the drive shaft 47 via the chain 48, and the worm wheel 42 is rotated by the engagement of the worm shaft 44 with the worm 43. For this reason, the sleeve 36
is rotated by engagement with the worm wheel 42, and the rotating shaft 31 is rotated in the opposite direction to the rotation of the sleeve 36 by the winding operation of the chain 21. As a result, the sleeve 36 and the nut 33 are not displaced in the axial direction despite their rotation, and the mounting load of the spring member 38 is kept constant. As a result, the weight of the elevating body 14 is balanced with the mounting load of the spring member 38, as in the case of stopping as described above, and as a result, the elevating body 1
The weight load of 4 is not applied to the electric motor 15, and the lifting body 1
Reference numeral 4 denotes an electric motor (8).The relatively small driving force of the electric motor (8) 15 causes the lift to rise smoothly.

Note that when the elevating body 14 is lowered by reversing the electric motor 15, the rotation directions of the worm wheel 42, sleeve 36, and rotating shaft 31 are reversed, but other operations are substantially the same as when the elevating body 14 is raised. In this case as well, the mounting load of the spring member 3 is kept constant and balanced with the weight of the elevating body 14, and the elevating body 14 is connected to the electric motor 15.
It descends smoothly due to the driving force of.

[Brief explanation of drawings]

Fig. 1 is a front view of a machine tool equipped with a balance device according to the present invention, Fig. 2 is an enlarged front view showing the main parts of Fig. 1, and Fig. 3 is a sectional view taken along line m-m in Fig. 1. , Figure 4 is the third
It is a sectional view taken along the line IV--IV in the figure. Explanation of symbols 11... Bed, 13... Base, 14... Lifting body, 21... Chain, 23... Sprocket wheel, 31... Rotating shaft, 36... Spring member, 38・・・
- Movable member (sleeve). (9) Figure 1

Claims (1)

[Claims] In a machine tool in which an elevating body such as a spindle head is attached to one side of a base that is erected on a head, a chain for suspending the elevating body is attached to the side wall of the base, and the chain is attached to the side wall of the base. A sprocket wheel that winds up or unwinds in response to the lifting and lowering operation of the body is fixed to one end of a rotating shaft that is pivotally supported on the base, and a spring member that is applied with an installation load corresponding to the weight of the lifting body is attached to the rotating shaft. A movable member that is assembled and held at a predetermined position on the rotating shaft in conjunction with the drive mechanism of the elevating body is engaged with the spring member to maintain a constant mounting load of the spring member. balance device.