Honing machine with oil-tight operating tank

A honing machine includes a machine housing enclosing a workpiece spindle and a tool spindle. The workpiece spindle includes a spindle collar with a spindle head configured to hold a workpiece. The tool spindle includes a cup-shaped holder with a honing ring located on an inside of the cup shaped holder. An operating tank is also located within the machine housing, where the operating tank surrounds the tool spindle in an oil-tight manner. The operating tank includes a panel with a recess, where the workpiece spindle is configured to insert the spindle head through the recess and form a first oil-tight seal between the recess and the spindle collar. The panel is moveable relative to the operating tank and tool spindle when the panel is carried along by the workpiece spindle during a feed motion. A second oil-tight seal is formed between the panel and the operating tank.

FIELD OF THE INVENTION

The present invention generally relates to a honing machine having a workpiece spindle displaceable by a motor with a spindle collar and a spindle head, a tool spindle for a honing ring, and a machine housing in which the workpiece spindle and the tool spindle are located.

BACKGROUND OF THE INVENTION

A honing machine of this kind is already known in the art, for example, from the “SynchroFine 205 HS” brochure from PRÄWEMA Antriebstechnik GmbH, Eschwege/Werra, Del.

During honing, the tooth flanks of a toothed workpiece, such as a gear wheel or a gear unit, are hobbed against a so-called honing ring, which usually comprises a ceramic material or is coated with a ceramic material. Material is removed from the tooth flanks of the workpiece in this process. The honing ring is essentially circular in shape and comprises tooth flanks pointing radially inwards. When the workpiece and the honing ring are hobbed against one other, the honing ring is rotated by means of a tool spindle and the workpiece is likewise rotated by means of a workpiece spindle.

Considerable heat is generated when the honing ring and the workpiece are hobbed against one another. In order to prevent the honing ring and the workpiece overheating, these are cooled by oil. In this process the oil is usually sprayed onto the contact area between the honing ring and the workpiece at high pressure. The oil also washes away fine particles and dust at the same time during this operation.

A fine oil mist arises as a result of spraying the oil onto the fast-rotating honing ring and the even faster-rotating workpiece, said oil mist being dispersed within the honing machine and being deposited more or less throughout the honing machine, for example on the inner walls and roof of the machine housing. After the honing procedure, workpieces are regularly heavily coated with oil and have to be washed in some cases before any further processing. Overall, the honing machine can be a considerable source of contamination in a production line.

In the current state of the art, such as in the case of the “SynchroFine 205 HS”, as mentioned above, parts of the honing machine, such as the workpiece feed region, are shielded from the tool spindle by intermediate walls to contain the oil mist dispersion.

The object of the invention is to create a honing machine with improved containment of oil mist dispersion. The present invention fulfills these needs and provides other related advantages.

SUMMARY OF THE INVENTION

An exemplary embodiment of the present invention includes a honing machine of the type mentioned initially, characterized by the fact that: an operating tank is located inside the machine housing, said tank surrounding the tool spindle in an oil-tight manner, the operating tank comprises a panel with a recess, it being possible to insert the workpiece spindle with the spindle head through the recess into the operating tank so that the spindle collar of the workpiece spindle seals the recess in an oil-tight manner, and the panel is mounted displaceably on the operating tank in an oil-tight manner so that the panel is carried along relative to the tool spindle during a feed motion of the workpiece spindle.

According to the present invention, the tool spindle is surrounded by an operating tank which confines the oil mist to its inner chamber. The operating tank is located inside the machine housing in this case and designed to be independent of the machine housing.

A panel with a recess (opening) is provided to enable the workpiece spindle or a workpiece carried on said spindle to access the operating tank. The workpiece spindle with the workpiece attached can be inserted into the recess so that the spindle collar then seals the recess in a completely oil-tight manner. As long as the spindle collar seals the opening, operations involving oil mist can be performed in the operating tank, such as spraying oil into the contact area between the honing ring and the workpiece during the actual honing procedure, or even spinning oil off the workpiece. When inserted, the workpiece spindle has the freedom of movement required to perform a feed motion towards the honing ring as the panel is mounted displaceably on the rest of the operating tank.

Seals, such as rubber seals, may be provided at the edge of the recess in the panel and in the region of the panel mount, to ensure oil-tightness. The operating tank typically also comprises a removable lid or a door so that the honing ring can be replaced in the event of wear or the type of workpiece can be replaced. This lid or door can also be sealed with seals, such as rubber seals. The operating tank is typically fully or partially made from sheet metal, especially sheet steel.

A deposit of oil mist on the inner walls and roof of the machine housing can be prevented by means of the oil-tight operating tank. It is possible to restrict the amount of oil deposited on or spinning onto the inner region of the operating tank. By spinning off the oil while it is still within the operating tank by means of the recess in the panel sealed by the workpiece spindle, it is also possible to obtain very clean workpieces by very simple means, which is often advantageous for processes following on from the honing procedure.

By restricting the oil mist to the inner chamber of the operating tank, large parts of the honing machine are also protected from the risk of explosion of an oil-air mixture. By locating the operating tank in the machine housing, the walls and roofs of the machine housing act as additional protective walls in the event of an explosion.

In an advantageous embodiment of the honing machine according to the invention, the tool spindle is aligned vertically with respect to its spindle axis. This makes it easier to mount the workpiece spindle, and the tool spindle can be loaded particularly simply, using the pick-up method, by a workpiece spindle which is also aligned vertically with its spindle axis.

An embodiment in which the operating tank is designed as an operating funnel is also preferable. With the funnel shape, a motor drive (such as an electric motor) can be arranged in the narrow region of the funnel in a space-saving manner. The narrow funnel region typically points downwards. In this case, it is also easy to collect any used oil.

A development of this embodiment in which the operating funnel comprises a preferably central lower oil drain is advantageous. Used oil can easily be removed via the lower oil drain. A central position (viewed radially) has been shown to be advisable in practice, but an oil drain in a non-central position is also possible. If required, the removed oil can be re-used in the honing process after cleaning or treatment.

An embodiment in which the tool spindle comprises a cup-shaped holder for the honing ring is especially preferable, an open side of the cup-shaped holder facing the recess and a closed side of the cup-shaped holder opposite the open side being fixed to a drive motor for the tool spindle. This ensures that the tool spindle has a compact design, especially compared to a holder which is driven by a motor located on a side section around the radial outer circumference of the holder. In this embodiment the drive motor is typically fixed to the closed side by means of a shaft which is constructed on or fixed to the closed side. When using an operating funnel, its inner chamber can be used to the optimum extent. It is also possible to accommodate parts of a hydraulic system for clamping the honing ring in position in the bottom section of the holder, which forms the closed side, thus also leading to a compact design. The bottom section is preferably designed to be continuous, but may also comprise recesses or holes. The bottom section provides the holder with mechanical stability. The described cup-shaped holder is thus also advantageous if the drive motor is not fixed to the closed side, which corresponds to another embodiment of the honing machine according to the invention.

An especially preferable embodiment is one in which the inner chamber of the operating tank is a maximum of three, or preferably a maximum of two, times larger than the space required by the tool spindle in the operating tank. This minimizes the area which can be contaminated by oil mist. Practical experience has shown that it is a good idea if the inner chamber of the operating tank is about twice as large as the area taken up by the tool spindle. All the necessary components can still be accommodated satisfactorily in the operating tank. The theoretical area which is at risk of explosion is minimized.

An embodiment in which the operating tank is connected to an explosion vent pipe, and especially where the explosion vent pipe leads to a region above the honing machine, is also advantageous. The explosion vent pipe prevents the walls of the operating tank being blown up or torn apart in the event of an explosion. The blast wave can escape through the vent pipe. This ensures improved protection for workers in the surrounding area. There are not normally any workers in the area above the honing machine (especially in the region of the roof of a building in which the honing machine is installed), thus safety is further improved if the explosion vent pipe leads accordingly to this area.

An embodiment in which the workpiece spindle is designed to turn a workpiece held on the spindle head at a speed of 10,000 rpm or more, preferably 15,000 rpm or more, is advantageous. Workpieces can be spun dry as a result of this high speed, i.e. the amount of oil (or contamination) remaining on the workpiece is negligible.

A particularly preferable embodiment of the honing machine according to the invention is where the honing machine has an electronic controller which can be used to control at least the displacement motion and speed of the workpiece spindle, and the electronic controller is programmed to spin a workpiece held on the spindle head of the workpiece spindle at high speed in the oil-tight operating tank after a honing procedure on this workpiece. During the honing procedure the workpiece is sprayed with oil (and contamination). The workpiece can be dried (and cleaned) by spinning at high speed. In this process the oil is only dispersed inside the operating tank (and not in the machine housing and especially not on the walls and roof of the machine housing) as the spindle collar seals the recess in the panel. Spin-drying takes place without any contact with the honing ring. Within the scope of the invention, speeds of 5,000 rpm are in particular regarded as high. The speed during spinning (spin-drying) is preferably at least 10,000 rpm.

In a preferred development of this embodiment the electronic controller is programmed to reach a higher speed when spinning the workpiece than in the preceding honing procedure on the workpiece. This thus improves drying and cleaning of the workpiece. If required, drying (and cleaning) during spinning can also be improved by blowing in compressed air; note that compressed air can be used in any speed range during this process as a general rule.

The scope of the present invention also covers usage of the above embodiment or its above development in accordance with the way the electronic controller is programmed. Particularly clean and dry workpieces can be achieved by spinning after the preceding honing procedure.

Further advantages of the invention will become evident from the description and the drawings. According to the invention, the features described above and explained in further detail can also be used individually or combined in any way or number. The embodiments illustrated and described should not be regarded as a complete list, but rather as examples describing the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1shows a honing machine1according to the invention, comprising a workpiece spindle3and a tool spindle4, said tool spindle4being arranged in an oil-tight operating tank5and therefore concealed inFIG. 1. The honing machine1further comprises a testing station6, a loading station7and an electronic controller8. In the illustrated embodiment, the electronic controller8and part of the loading station7are arranged outside a machine housing2for the honing machine1. The remaining assemblies are located inside the machine housing2. Side walls, a roof and a floor plate form part of the machine housing2in this case and all surround an inner chamber IR.

Workpieces9which are supplied to the loading station7in a manner which is not illustrated in any greater detail are brought into the inner chamber IR, by means of a conveyor belt system in the loading station7, through an opening10in the machine housing2. The workpiece9can be picked up here using a gripper11which is telescopic in the vertical direction and which can be displaced horizontally on a portal system12, then the workpiece9can be taken to the testing station6and placed on a test holder6a. A master wheel6bcan then be moved horizontally onto the workpiece9on the test holder6aand hobbed against said workpiece. The quality of the workpiece9can be verified from the displacement position of the master wheel6bduring this hobbing operation. A workpiece9which is found to be unsuitable for further processing is taken back to the loading station7by the gripper11and transferred out.

A workpiece9which is found to be suitable for further processing is picked up by the workpiece spindle3using the pick-up method, taken to the fixed tool spindle4using a portal system13(comprising a compound slide rest13a, so that the workpiece spindle3can be moved horizontally and vertically), and subjected to a honing procedure here (seeFIG. 2a-2c). The workpiece9is then taken off the workpiece spindle3and taken back to the loading station7by the portal system13and transferred out.

During this operation the electronic controller8controls the loading station7, the testing station6, the gripper11, including the portal system12, the workpiece spindle3(also with respect to speed and relative phase) including the portal system13and also the tool spindle4(with respect to speed and relative phase), see the monitoring and control lines shown by way of dashes. In the illustrated embodiment, the electronic controller is responsible for coordinating workpiece transfer operations, test hobbing and performing the honing procedure, including spinning (see below). Note that the electronic controller8can also be located inside the machine housing2in an alternative design.

The tool spindle4is located in the operating tank5which is funnel-shaped in this case. The operating tank5has its own oil-tight boundaries on all sides (with the exception of a recess for the workpiece spindle3, see below), said boundaries preferably being made from sheet steel, and in particular having no walls in common with the walls of the machine housing2(including roof and floor plate). The operating tank5is mounted on adjustable feet in this case. The operating tank5has an explosion vent pipe14which leads to above the honing machine1, preferably into the open air through a building roof.

FIG. 2ashows the region of the tool spindle4in the operating tank5fromFIG. 1in detail. The tool spindle4comprises a cup-shaped holder20, which in this case is positioned with its open side OS at the top and its closed side GS at the bottom. The cup-shaped holder20accordingly has a bottom section21and a circumferential side section22. The circumferential side section22comprises a circumferential hydraulic expansion element23on its inner side, a honing ring24being able to be clamped in the radial direction R and centered in the holder20by means of said expansion element. When the pressure of a hydraulic medium25, shown as a dotted area, rises, the expansion element23expands radially inwards and vice versa. The pressure of the hydraulic medium25can be adjusted by means of an adjustment element (in this case an adjustment screw26, which determines the partial volume of a hydraulic chamber27which is filled with hydraulic medium25). The hydraulic expansion element23is connected to the hydraulic chamber27by means of a plurality of hydraulic lines28. The hydraulic chamber27, the adjustment element and the hydraulic lines28in some cases are located in the bottom section21, so that the tool spindle4can be designed to be compact in the radial direction (in the horizontal direction inFIG. 2a) (also seeFIG. 3for the hydraulic system).

The holder20has a shaft29on the bottom side. The holder20is mounted on said shaft and the holder20is able to be driven by means of a drive motor30, which is an electric motor in this case, via said shaft. The holder20(and thus also the honing ring24) rotates around a vertical axis VA for the honing procedure. Drainage channels31are also provided in the holder20, through which the oil, which is sprayed onto the contact area between the honing ring24and the workpiece9during the honing procedure (via an oil feed line32which is not fixed to the holder20and which has an oil nozzle32a), can flow out of the cup-shaped holder20; during this operation an oil pressure of 40 bar and over, preferably 60 bar and over, can be used. The operating tank5has a central drain33on its underside for oil, through which used oil can drain.

The operating tank5surrounds the tool spindle4, comprising the holder20(including the shaft29and honing ring24) and the drive motor30, in a funnel shape. The boundary walls of the operating tank5are designed to be oil-tight. The partial volume of the inner chamber of the operating tank5taken up by the tool spindle4(including the area in the “cup” surrounded by the circumferential side section22) in this case corresponds to approximately half the overall volume of the inner chamber of the operating tank5, i.e. the inner chamber of the operating tank5is approximately twice as large as the space required by the tool spindle4.

The upper side of the operating tank5is formed by a lid34, which is fixed in a rigid and oil-tight manner to the rest of the operating tank5during normal operation in a manner which is not shown in greater detail, and said lid can be removed in order to change the honing ring24. The operating tank5otherwise has no doors or similar items. The lid34comprises a panel35, which is mounted in the lid34such that it can be moved in the horizontal direction H in a mount37which has a C-shaped cross-section on both sides. The lid34(including the panel35) seals the upper region of the operating tank5in an oil-tight manner with the exception of a recess (opening)36.

The workpiece spindle3can be inserted into the operating tank5through the recess36. To this end, a spindle head3aof the workpiece spindle3, said spindle head carrying a workpiece9, is first inserted into the recess36. In the situation illustrated inFIG. 2a, the workpiece spindle3must be moved downwards for this purpose.

If the panel35with the recess36is not positioned precisely beneath the workpiece spindle3, the panel35is aligned by means of tapered surfaces3con the workpiece spindle3in its mount37in the lid34, such that a spindle collar3bseals the recess36in an oil-tight manner when the workpiece spindle3is lowered further, seeFIG. 2b.

The workpiece9can then be advanced to the left towards the honing ring24by moving the workpiece spindle3, see ZU arrow. The panel35in its mount37is also carried along in this operation, or in other words moved to the left.

FIG. 2cthen shows the position in which the workpiece9, a gear wheel in this case, is inserted completely into the toothed flank of the honing ring24with its toothed flank. In this position, the honing ring24is rotated around the vertical axis VA and the workpiece9is rotated around the likewise vertical spindle axis SA and the two are hobbed against one another. Oil is sprayed through the oil nozzle32afor cooling purposes and to remove dust from the contact area KB between the honing ring (tool)24and the workpiece9, at least during hobbing.

After the honing procedure on the workpiece9, said workpiece is moved back to the right, again in the horizontal direction, by means of the workpiece spindle3, for example into the position shown inFIG. 2b. Here the workpiece spindle3, with the oil supply to the oil nozzle32aswitched off, can again operate at high speed by means of the workpiece9in order to spin the workpiece9dry. The speed is preferably higher during spin-drying than during the honing procedure. Typical speeds during spin-drying within the scope of the invention are at least 10,000 rpm. The oil, which is released from the workpiece9during spin-drying, remains inside the operating tank5as the recess36remains blocked by the spindle collar3b, and thus the operating tank5is hermetically sealed. After spin-drying, the workpiece9with the workpiece spindle3can be retracted upwards from the operating tank5through the recess36.

FIG. 3illustrates parts of the hydraulic system for the holder20in a horizontal cross-section, concealed structures located beneath the level of the cross-section are shown as dashed lines.

The circumferential hydraulic expansion element23is formed on the inner side of the circumferential side section22. This expansion element23is connected to the central hydraulic chamber27(viewed radially) in the bottom section21by means of four hydraulic lines28which run in a star formation in this case. The pressure in the expansion element23can be adjusted in a simple manner via the hydraulic lines28by means of the (single) adjustment element (see reference numeral26for the adjustment screw inFIG. 2a), with which the pressure in the hydraulic chamber27is adjusted.

The drainage channels31through which oil can be drained through the bottom section21into the lower region of the operating tank5are also shown. Note that the drainage channels31on the upper side of the bottom section21may also open closer to the circumferential side section22, especially on the edge of the circumferential side section22, so that the oil carried outwards as a result of centrifugal force during rotation of the holder20can be drained more readily.

Although several embodiments have been described in detail for purposes of illustration, various modifications may be made to each without departing from the scope and spirit of the invention. Accordingly, the invention is not to be limited, except as by the appended claims.