JP2526161Y2 - Waterproof structure of direct drive rotary indexing table - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a direct drive type rotary indexing table which rotates an indexing table by a predetermined angle and positions the indexing table by a direct drive method without using a reduction gear, and in particular, an indexing method. The present invention relates to a waterproof structure capable of effectively preventing cutting liquid or moisture from entering the inside of a table.

[Conventional technology]

The direct drive type rotary indexing table that does not use a reduction mechanism
There is no backlash or noise caused by the reduction gear, and the clamping mechanism is located close to the table rotation shaft to increase the torsional rigidity, so that the torsional deformation of the indexing table shaft when a cutting load is applied to the work W is prevented. There is an advantage that processing accuracy is improved. As a conventional direct drive type rotary indexing table of this type, there is, for example, a table previously proposed by the present applicant (JP-A-62-88550). In this device, a motor housing is supported via an elastic body so as to be movable in an axial direction in a fixed casing, and a motor stator is provided in the motor housing. An indexing table is rotatably connected via a rotor to a motor rotor arranged coaxially with the motor stator. Further, a rotation detector for detecting a rotation angle of the indexing table and a clamp mechanism for holding the indexing table at a stop position are provided.

If cutting oil, moisture, or the like infiltrates into the inside while the direct drive type rotary indexing table is mounted on a machine tool and used, a short circuit of an internal electric component or a leakage accident may be caused. Therefore, a waterproof structure is provided in which a lip packing is attached near the outer periphery of the lower end surface of the indexing table to seal between the lower end surface and the upper end surface of the housing.

[Problems to be solved by the invention]

The waterproof structure of the conventional direct drive rotary indexing table has a structure in which a lip of one V-type lip packing mounted on the lower end surface of the indexing table is slidably contacted with the upper end surface of the housing to seal. If the water-soluble cutting oil scattered in the state of (1) is sprayed, it is sufficiently waterproof. However, if the water-soluble cutting oil is violently sprayed on the seal area or is immersed in oil,
Waterproofness is not enough. Against such a case, by conventionally to feed the 0.5 kgf / cm ² about low pressure air into the housing, causing the contact surface leakage to the outside by pressurizing the V-shaped lip seal from the inside, the water-soluble It prevented the penetration of cutting oil and the like inside. However, if the pressurized air is not sufficiently dehumidified, it may rust and impair the function of the direct-drive rotary indexing table, and it is difficult to use such a waterproofing means in an area with poor conditions.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to provide a waterproof structure of a direct drive type rotary indexing table which is not affected by the water content of a pressure air source. is there.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a motor stator fixed to a housing, a motor rotor disposed coaxially in the housing in opposition to the motor stator, and a motor stator fixed to the motor rotor and via a bearing. A rotor rotatably supported by the housing, an indexing table fixed to the rotor, which cannot be moved in the axial direction, a detector stator mounted on the housing, and a detector rotor mounted on the rotor; A direct-drive rotary indexing table having a rotation detector for detecting a rotation angle of an indexing table and a clamp mechanism for holding the indexing table at a stop position, wherein the housing and the indexing table are provided. Lip packings are arranged in two stages inside and outside at a distance in the radial direction between the opposing surfaces of the lip packings. A path for pressurized air to be supplied to the housing is provided in the housing, the inner lip packing is mounted so as to seal the pressure of the pressurized air in the space with the lip tip facing radially outward, and the outer lip packing also has a lip tip. The pressure of the pressurized air in the space is attached to the outside so as to be able to leak to the outside in the radial direction.

[Action]

The pressurized air supplied to the space between the inner and outer lip packings spaced apart in the radial direction presses the outer lip packing from the inside to the outside. The outer lip packing has the lip tip directed radially outward, and the pressing force of the pressurized air acts in the direction to lift the lip tip, so the self-sealing force of the outer lip packing weakens, causing leakage of the contact surface and pressure. The air leaks to the outside, and the cutting fluid or the like is blown off by the pressure of the leaked air to prevent the cutting fluid from entering.

On the other hand, the pressurized air presses the inner lip packing from outside to inside. The inner lip packing has the lip tip directed radially outward, and the pressing force of the pressurized air acts on the lip packing from outside, so the lip tip is urged toward the housing or indexing table side with which it slides. Accordingly, the self-sealing force of the inner lip packing is strengthened, and the intrusion of the pressurized air into the inside is prevented. Therefore, even if the pressurized air containing water is supplied, the inside of the drive type rotary indexing table is not directly affected, and the function of the indexing table is not impaired.

〔Example〕

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

FIG. 1 is a vertical sectional side view of a direct drive type rotary indexing table,
FIG. 2 is an enlarged sectional view of the waterproof structure. The direct drive type rotary indexing table includes an electromagnet tooth as a motor stator 12 fixed to the inner surface of the housing 11 and a motor rotor 13 coaxially arranged in the housing 11 so as to face the motor stator 12. It is a motor built-in type with a structure in which the teeth of the iron core face each other. The motor stator 12 has a plurality of magnetic poles having a plurality of teeth, and the motor rotor 13 is rotated by sequentially exciting each magnetic pole. The phases of the teeth are changed between the magnetic poles of the motor stator 12.

The housing 11 is cylindrical and has an axial hole H at the center thereof. The housing outer cylinder 11B is attached to the housing inner cylinder 11A with bolts B1 and is integrally assembled. The motor M is housed in a space between the housing inner cylinder 11A and the housing outer cylinder 11B. That is,
A motor stator 12 having a coil CA is press-fitted into the inner peripheral portion of the housing outer cylinder 11B and fixed with bolts B2.
On the inner peripheral side of the motor stator 12, a motor rotor 13 provided with teeth of the same pitch is rotatably arranged.

An annular rotor 14 extending in the axial direction extends from one end of the motor rotor 13, and is fixed so as to be integrally rotatable with a bolt B3. An inner ring 15a of a cross roller bearing 15 is fitted on an outer peripheral surface of an intermediate portion of the rotor 14, and a fixing member 16
Is fixed by tightening the fixing bolt B4. The outer ring 15b of the cross roller bearing 15 is fitted on the upper part of the inner peripheral surface of the housing outer cylinder 11B, and is fixed to the upper end surface of the housing outer cylinder 11B by an annular bearing retainer 17 fixed with a bolt B5. I have.

An indexing table 20 has bolts B on the upper end surface 14a of the rotor 14.
It is fixed at 6.

In a space S surrounded by the housing inner cylinder 11A and the rotor 14 on the lower side of the indexing table 20, a resolver 21 which is a high-resolution rotation detector for positioning the motor with high accuracy.
Is built-in. The detector stator 22 of the resolver 21 having the coil CL has a bolt B7 on the inner surface of the housing inner cylinder 11A.
It is fixed with. On the other hand, the detector rotor 23 of the resolver 21 is
Is fixed with bolts B8. The detector stator 22 of the resolver 21 has the same teeth as the motor stator 12, and the coil CL is wound around each magnetic pole. The detector rotor 23 of the resolver 21 has the same pitch teeth as the motor rotor 13.

When the motor rotor 13 rotates, the detector rotor 23 of the resolver 21 also rotates, so that the reluctance between the teeth with the detector stator 22 changes. The change is digitized by a resolver control circuit of a drive unit (not shown), and is used as a position signal to detect the rotation angle of the detector rotor 23 and thus the rotation position of the rotor 14.

A clamp mechanism 25 is mounted above the resolver 21 housed in the space S and on the back side of the indexing table 20. The clamp mechanism 25 has a donut plate-shaped diaphragm made of spring steel, and this diaphragm is a first elastic member 26 whose inner peripheral side is cantileverly fixed to an upper end surface of the housing inner cylinder 11A with bolts B9. I have. The free end side of the outer periphery of the first elastic member 26 is a friction surface 26a,
And a stepped portion 14b formed in the middle stage. The clamp mechanism 25 further includes a friction surface 26 of the first elastic member 26.
The cylinder 27 is pressed against the step 14b of the rotor against its elasticity, the piston 30 slidably contacts the cylinder 27 in the axial direction, and the lower end surface of the piston 30 is connected to the inner cylinder 11A of the housing. A second elastic member 31 is provided as a doughnut-shaped diaphragm made of spring steel, which stops the piston 30 in the axial direction and prevents the shaft from rotating.

The cylinder 27 has a cylindrical central portion and a housing inner cylinder 11A.
A flat portion 27A is spread radially from the upper end of the cylinder in a disk shape, and the outer end is again formed into a cylindrical shape. The lower end (back side) 27b of the cylindrical portion 27B at the outer peripheral end is brought into contact with the upper surface of the free end of the first elastic member 26.

The piston 30 has substantially the same shape as the cylinder 27, and is in sliding contact with the inner surface side of the cylinder 27 so as to be movable in the axial direction. Then, the cylindrical portion 30B at the outer peripheral end of the piston flat portion 30A
The upper end 30b is a friction surface, and is opposed to the back surface of the indexing table 20 so as to be able to be separated.

Further, the piston 30 facing the flat portion 27A of the cylinder 27
The pressurizing chamber 33 is formed by cutting the lower surface side of the flat portion 30A of the above to a small depth. Needless to say, the upper surface side of the plane portion 27A of the cylinder 27 may be cut off. In short, the pressurizing chamber 33 may be provided between the opposed plane portions of the cylinder 27 and the piston 30.

An outer peripheral portion of the second elastic member 31 is fixed to an inner surface step portion of the inner cylinder 11A of the housing with a bolt B10, and a lower end of the piston 30 is locked on the surface of the second elastic member 31 with a bolt B11. Have been. In the unclamped state in which no fluid pressure is applied to the inside of the pressurizing chamber 33, the second elastic member 31 keeps a flat shape, and the friction surface 30b on the outer peripheral end of the piston 30 is
Is separated from the back surface.

The fluid path 35 for feeding the pressurized fluid to the pressurizing chamber 33 when the indexing table 20 is clamped connects the flow passage 35A formed in the housing inner cylinder 11A and the flow hole 35B formed in the piston 30. It is formed.

The above-mentioned motor stator 12, motor rotor 13, rotor 14,
The space S in which the resolver 21 and the like are disposed is sealed with an oil seal A as a rotary seal member and an O-ring C as a seal member for a sliding portion and a fixed portion.

In particular, between the upper end surface of the housing outer cylinder 11B which rotates relatively and the lower end surface of the indexing table 20 opposed thereto, the outer lip packing L1 and the inner lip Sealing is performed in two stages inside and outside by packing L2 to form a waterproof structure. In this embodiment, the outer lip packing L1 is mounted in a packing groove 36 provided on the lower surface of the indexing table 20, and the outward lip tip L1a is slidably contacted with the upper end surface of the housing outer cylinder 11B. On the other hand, the inner lip packing L2 is provided with a concave step 17a on the bearing retainer 17 attached to the upper end of the housing outer cylinder 11B, mounted on the concave step 17a, and the lip tip L2a facing outward. Is in sliding contact with the lower surface of the indexing table 20.

And, in order to supply pressurized air to the space between both lip packings L1 and L2, a pressurized air supply path 38 for sealing is provided from the air supply port 37 on the side surface of the housing outer cylinder 11B to the concave step 17a, The inner lip packing L2 is configured to seal the pressure of the pressurized air, and the outer lip packing L1 is configured to leak the pressure of the pressurized air to the outside.

Reference numeral 42 denotes a proximity switch as an origin detection sensor for detecting a reference point when detecting the rotation position of the indexing table 20, and is mounted on a side surface of the housing outer cylinder 11B. Reference numeral 43 denotes a metal piece fixed to a specific position on the outer peripheral surface of the rotor 14 with bolts B12 and B13 so as to face the origin detection sensor 42. 44 is a spring pin for positioning the rotor 14 and the indexing table 20.

 Next, the operation will be described.

First, the operation of the waterproof structure in which the lip packing is provided in two stages inside and outside will be described with reference to FIG. Pressurized air P of about 0.5 kgf / cm ² is supplied to the space between the outer lip packing L1 and the inner lip packing L2 via the pressurized air supply path 38. The pressurized air P presses the outer lip packing L1 from inside to outside. In general, the lip packing has a directional sealing force, and the self-sealing force is weakened by applying a back pressure to the outer lip packing L1. As a result, the contact air leaks at the lip tip L1a, and the pressure air P leaks to the outside, and the cutting fluid or the like is blown off by the pressure to prevent the inside from entering.

On the other hand, since the inner lip packing L2 is pressurized from the outside to the inside, the self-sealing force is strengthened, and the entry of the pressurized air into the inside is prevented. Therefore, even if the pressurized air containing a large amount of water is supplied, it does not affect the inside of the directly driven rotary indexing table at all, and the function is not impaired.

Next, the operation of the internal structure will be described. Motor stator 12
When a motor current is supplied to the coil CA via a drive unit (not shown), the teeth of the motor stator 12 are excited in a predetermined order, and the motor rotor 13 rotates. When the motor rotor 13 rotates, the detector rotor 23 of the resolver 21 also rotates, so that the reluctance between the teeth with the detector stator 22 changes. The change is digitized by a resolver control circuit of a drive unit (not shown) and is used as a position signal to regulate the rotation angle of the detector rotor 23 of the resolver 21 and thus the rotation angle of the rotor 14, and the indexing table 20 is indexed. You.

After the indexing is completed, the indexing table 20 is clamped by the clamp mechanism 25. At that time, pressurized air (or hydraulic pressure) is sent into the pressurizing chamber 33 via the fluid path 35. With this fluid pressure, the cylinder 27 is pressed in the opposite direction of the indexing table 20, and moves downward in FIG. 1 against the elastic force of the first elastic member 26. As a result, the friction surface 26a at the free end of the first elastic member 26 is strongly pressed against the step 14b of the rotor 14, and the rotation of the rotor 14 and thus the indexing table 20 is prevented.

At the same time, the piston 30 is pressed in a direction opposite to the cylinder 27, that is, toward the indexing table 20, and moves upward in the drawing against the elastic force of the second elastic member 31. As a result, the friction surface 30b on the outer peripheral end of the piston 30 is
Strongly pressed against the back surface of the index table 20 to prevent the indexing table 20 from rotating. Thus, since the rotation of the indexing table 20 is clamped by applying a brake to not only the rear surface of the indexing table 20 but also the surface of the rotor 14, the clamping force is doubled. Therefore, even if a force such as a cutting force is applied to the work, the work can always be accurately positioned and held at the regular stop position.

Note that a thrust reaction force is applied to both the rotor 14 and the indexing table 20. as a result,
The thrust displacement force of the indexing table 20 is canceled, and the axial displacement of the indexing table 20 is also prevented. Also, the rotor 14
Unnecessary thrust force is also prevented from being applied to the cross roller bearing 15.

FIGS. 3 and 4 show another example of the mounting structure of the lip packings L1 and L2.

FIG. 3 shows the outer lip packing L1 and the inner lip packing L2 both mounted on the housing 11 side.

FIG. 4 shows the outer lip packing L1 and the inner lip packing L2 both mounted on the indexing table 20 side.

In any case, the waterproof function and effect are the same as those in FIG.

Note that the lip packing in the waterproof structure is not limited to that of the above-described embodiment, but may include V packing of other shapes, cup packing having an L-shaped cross section, U packing, U cup packing, W packing, etc. What is necessary is just to have directionality.

Further, the internal structure of the direct drive type rotary indexing table provided with the waterproof structure is not limited to the above embodiment. The waterproof structure of the present invention can be applied to various types of direct-drive rotary indexing tables proposed by the present applicant.

[Effect of the invention]

As described above, according to the present invention, the lip packings are arranged in two stages inside and outside with a radial interval between the opposing surfaces of the housing and the indexing table. A path for pressurized air to be supplied to the space is provided, and the inner lip packing is mounted so as to seal the pressure of the pressurized air in the space with the lip tip facing radially outward,
The outer lip packing was also mounted so that the pressure of the pressurized air in the space could be leaked to the outside with the lip tip facing radially outward. Therefore, the pressurized air presses the inner lip packing from the outside in the radial direction to the inside, but since the inner lip packing directs the lip tip outward in the radial direction, the pressing force by the pressurized air from the outside is reduced. Acting on the lip packing, the tip of the lip is urged against the side of the housing or the indexing table with which the lip slides, so that the self-sealing force of the inner lip packing is strengthened and entry of the pressurized air into the inside is prevented. Therefore, even if the moisture content of the pressurized air is large, it does not directly affect the inside of the drive-type rotary indexing table, thereby preventing the function of the indexing table from being impaired. Here, since the indexing table of the present invention is fixed to the rotor, and the rotor is further fixed to the motor rotor, the indexing table is fixed in the axial direction. The axial displacement of the indexing table during unclamping is prevented,
The lip contact pressure of the lip packing is kept constant, so that good sealing performance can be obtained.

In addition, the pressurized air presses the outer lip packing from inside to outside, and the lip tip is directed radially outward.For the outer lip packing, the pressing force of the pressurized air acts in the direction to lift the lip tip. As a result, the self-sealing force of the outer lip packing is weakened, and the pressurized air leaks to the outside due to the contact surface leakage. Does not enter between the housing and the indexing table from the outside, and the function of the indexing table is not impaired.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is an enlarged sectional view of a waterproof structure of FIG. 1, and FIGS. 3 and 4 are partially enlarged views showing other examples of the waterproof structure. It is sectional drawing. In the figure, 11 is a housing, 12 is a motor stator, 13 is a motor rotor, 14 is a rotor, 15 is a bearing, 20 is an indexing table,
21 is a rotation detector (resolver), 25 is a clamp mechanism, L1 is an outer lip packing, L2 is an inner lip packing 38 and a pressurized air supply path.

Claims (1)

(57) [Scope of request for utility model registration] 1. A motor stator fixed to a housing, a motor rotor disposed coaxially in the housing so as to face the motor stator, and a shaft fixed to the motor rotor and rotatable about the housing via a bearing. , A non-axially movable indexing table fixed to the rotor, a detector stator mounted on the housing and a detector rotor mounted on the rotor, and a rotation angle of the indexing table. And a clamp mechanism for holding the indexing table at a stop position, the waterproof structure of a direct drive type rotary indexing table, wherein the housing and the indexing table are opposed to each other. The lip packing is provided between the inner and outer tiers with a radial interval between the two surfaces, and the pressurizing air is supplied to the space between the lip packings. A path is provided in the housing, the inner lip packing is mounted so as to seal the pressure of the pressurized air in the space with the lip tip facing radially outward, and the outer lip packing also has the lip tip facing radially outward. A waterproof structure for a direct-drive rotary indexing table, wherein the pressure of the pressurized air in the space is attached to the outside so as to leak to the surface.