JPH0211086B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing device for a displacement measuring machine, and in particular, a sealing device suitable for use in a linear displacement measuring machine, which is fixed to one member whose relative movement is detected. a hollow case in which an opening is formed along a line of movement of the other member to be detected, and the displacement of the other member is transmitted to a displacement detection mechanism housed inside the hollow case via the opening. a connecting rod arranged on both sides of the opening of the hollow case;
The present invention relates to an improvement in a sealing device for a displacement measuring machine having a flexible lip member whose tip end is brought into butt contact with the connecting rod.

Generally, in a measuring machine that measures the length of an object, when measuring the amount of movement of an object that moves relatively, such as the amount of movement of the measuring head with respect to the main body, the amount of movement of a slider with respect to the column, etc., the main scale is placed on one side. A displacement measuring device is known in which a detector including an index scale is fixed to the other end and the relative displacement between the main scale and the detector is read by, for example, an optical method or an electromagnetic method.

Although such displacement measuring machines have high precision, their structures are also minute, and there are many problems in maintaining a certain level of precision, increasing adaptability to the usage environment, and increasing practical value. . That is, for example,
In an optical displacement measuring machine that uses a main scale and an index scale that have graduations on the μm order, it is necessary to maintain the gap between the two scales on the μm order, and in order to save power, a relatively weak light source is used. Therefore, it must be completely dust-proof and drip-proof.

To achieve this purpose, as shown in FIGS.
A hollow case 20 in which an opening 20a is formed along the movement line of the other member whose relative movement is detected, such as a workpiece or tool 12, which is fixed at zero.
, a connecting rod 24 for transmitting the displacement of the tool 12 to the displacement detection mechanism 22 housed inside the hollow case 20 via the opening 20a, and both sides of the opening 20a of the hollow case 20. Some devices are provided with a sealing device consisting of flexible rubber lip members 26 and 28, which are disposed at the top of the connecting rod 24 and have their tips brought into butt contact with the connecting rod 24.

In the figure, 30 is made of glass or the like, one end of which is inserted into a fixing groove 32 provided in the longitudinal direction in the hollow case 20, and fixed using a rubber rod 34, adhesive 36, etc., and a scale surface 30a. Main scale with vertical striped graduations, 38
is a slider configured to move in the longitudinal direction of the main scale 30 while maintaining a predetermined positional relationship with the main scale 30 by a sliding piece 40 that slides on the surface of the main scale 30; Reference numeral 42 denotes an index scale 44, 46, which is fixed to the surface of the slider 38 facing the main scale graduation surface 30a and has vertical striped graduations similar to the main scale 30.
A light emitting element and a light receiving element 4 are fixed to the slider 38 with the main scale 30 and index scale 42 sandwiched therebetween, respectively.
8, the movement of the connecting rod 24 is controlled by the slider 3.
For example, a linear cantilever spring is used as the coupling means for transmitting the signal to the terminal 8.

According to the sealing device using the pair of lip members 26 and 28 as described above, compared to a device that seals the opening 20a of the hollow case 20 with a magnetic metal band or a device provided with a brush, It has a feature of being able to effectively prevent dust and oil droplets from entering with a relatively simple configuration. However, in the past, due to the penetrating and transverse nature of the connecting rod 24 for relative movement, the lip member 24 was
6 and 28 have the same shape and are arranged symmetrically.In recent years, the range of applications of displacement measuring instruments has expanded, and for example, when used as a feedback signal generator for numerically controlled machine tools,
There is a problem in that it is not possible to prevent machine oil from entering through the joint between the pair of lip members 26 and 28.

Further, the conventional sealing device has a problem in that it does not have any function to remove oil droplets that have entered between the lip members 26, 28 and the connecting rod 24.

The present invention has been made to solve the above-mentioned conventional problems, and is designed to remove droplets that have entered the hollow case.
It is an object of the present invention to provide a sealing device for a displacement measuring machine that can be expelled to the outside before reaching a displacement detection mechanism.

The present invention provides a hollow case that is fixed to one member whose relative movement is detected and has an opening formed along a movement line of the other member whose relative movement is detected, and a hollow case that detects displacement of the other member. , a connecting rod for transmitting a signal to a displacement detection mechanism housed inside the hollow case through the opening, and a connecting rod for shielding a penetrating portion of the connecting rod arranged on both sides of the opening of the hollow case. In a sealing device for a displacement measuring device having a sealing member, a liquid receiving groove extending along the opening is provided on at least one of the inner surfaces of the hollow case, and a bottom of the liquid receiving groove communicates with the outside of the hollow case. The above object is achieved by providing a drain hole and a filter for preventing dust from entering from the outside.

Further, a liquid barrier is provided in the hollow case between the liquid receiving groove and the displacement detection mechanism to ensure that liquid droplets are removed.

Further, by forming the liquid barrier as an elastic member whose tip is brought into contact with the connecting rod, the liquid droplet removal function is further enhanced.

Furthermore, by providing a slope on the side surface of the liquid receiving groove of the elastic member to quickly guide the liquid droplets that have entered into the liquid receiving groove, the liquid droplets can be quickly guided even when the connecting rod is placed in an upright position. It is meant to be excluded.

Furthermore, a screw hole for screwing a sealing screw is formed in the drain hole, so that the drain hole of the hollow case disposed on the upper side can be easily sealed.

Further, the sealing member is a flexible lip member whose tip end is brought into butt contact with the connecting rod.

Alternatively, the sealing member is a metal band that is attracted by magnets placed on both sides of the opening of the hollow case.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a sealing device for a linear displacement measuring machine to which the present invention is applied will be described in detail with reference to the drawings.

As shown in FIG. 3, the first embodiment of the present invention has a hollow case 20 and a connecting rod 2 similar to the conventional example.
4 and lip members 26 and 28, the opening 20 of the hollow case 20 is provided on both inner surfaces of the hollow case 20.
An oil receiving groove 50 extending along a is provided, and the oil receiving groove 5
An oil drain hole 52 communicating with the outside of the hollow case 20 is provided at the bottom of the hollow case 20, and a filter 54 is provided in the oil drain hole 52 to prevent dust from entering from the outside.

An oil dike 56 is provided in the hollow case 20 between the oil receiving groove 50 and the displacement detection mechanism 22.

Further, the oil drain hole 52 is formed with a thread for screwing a sealing screw 58 thereinto, and the sealing screw 58 is screwed into the upper oil drain hole 52 .

According to this embodiment, the connecting rod 24 and the lip member 2
If oil droplets that have entered the inside of the hollow case 20 from between the holes 6 and 28 fall from the connecting rod 24 before reaching the displacement detection mechanism 22, they are collected by the oil receiving groove 50 and drained through the filter 54. Since the oil droplets are discharged to the outside from the oil hole 52, the oil droplets do not remain in the hollow case 20 for a long time and do not adversely affect the displacement detection mechanism 22. Further, since the oil drain hole 52 is provided with a filter 54, dust does not enter from the outside.

In this embodiment, an oil barrier 56 is provided between the oil receiving groove 50 and the displacement detection mechanism 22, so that it is possible to reliably prevent oil droplets from entering in the direction of the displacement detection mechanism 22. can.

Further, in this embodiment, an oil receiving groove 50, an oil drain hole 52, and a filter 5 are provided on both inner surfaces of the hollow case 20.
4. Since the oil barrier 56 is provided, the hollow case 2
Even if the mounting orientation of the 0 is different, it can be easily handled.

Further, since the oil drain hole 52 is formed with a thread for screwing the sealing screw 58, the oil drain hole 52 which is not used can be easily and reliably sealed. This prevents oil droplets, dust, etc. from entering from the oil drain hole on the non-use side.

Next, a second embodiment of the present invention will be described in detail.

As shown in FIG. 4, this embodiment includes a hollow case 20, a connecting rod 24, lip members 26, 28, and an oil receiving groove 50, which are similar to the conventional example and the first embodiment.
In a sealing device for a linear displacement measuring machine having an oil drain hole 52, a filter 54, and a sealing screw 58, a tip of the connecting rod 24 is located between the oil receiving groove 50 and the displacement detection mechanism 22. An oil barrier made of an elastic member 60 that comes into contact with the oil barrier is provided. The other points are the same as those of the conventional example and the first embodiment, so the explanation will be omitted.

In this embodiment, the elastic member 60 allows oil droplets traveling along the connecting rod 24 to be removed more reliably.

Incidentally, as shown in FIG.
By providing the slope 60a to guide the oil droplet to 0, even when the connecting rod 24 is used in an upright position, the oil droplets that have entered can be quickly guided to the oil receiving groove 50.

Furthermore, in addition to the configuration of the embodiment described above, it is also possible to connect a discharge pump driven by using the relative movement of the connecting rod 24, for example, to the oil drain hole 52 to further improve the oil droplet removal performance. It is.

In each of the above embodiments, the sealing members for blocking the penetration portion of the connecting rod 24 were lip members 26 and 28, but the configuration of the sealing members is not limited to this, and for example, It is also possible to use a metal band that is attracted by magnets placed on both sides of the opening 20a of the hollow case 20.

In each of the above embodiments, the present invention was applied to a linear displacement measuring machine equipped with an optical displacement detection mechanism, but the scope of application of the present invention is not limited to this. It is obvious that the present invention can be similarly applied to other displacement measuring machines such as a linear displacement measuring machine equipped with a linear displacement measuring machine.

As explained above, according to the present invention, oil droplets that have entered the hollow case can be reliably removed, and therefore, the displacement detection mechanism and the like are not adversely affected, which is an excellent effect.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the configuration of a linear displacement measuring machine with a photoelectric displacement detection mechanism that employs a conventional sealing device. Fig. 2 is a cross-sectional view taken along the - line in Fig. FIG. 3 is a sectional view showing the configuration of a first embodiment of a linear displacement measuring device having an optical displacement detection mechanism, in which the sealing device of the displacement measuring device according to the present invention is adopted, and FIG. FIG. 5 is a cross-sectional view showing the main structure of a modification of the second embodiment. 20... Hollow case, 20a... Opening, 22... Displacement detection mechanism, 24... Connecting rod, 26, 28... Lip member, 50... Oil receiving groove, 52... Oil drain hole, 54... Filter, 56... Oil dike, 58...Sealing screw, 60...
Elastic member, 60a... slope.

Claims (1)

[Scope of Claims] 1. A hollow case fixed to one member whose relative movement is detected and having an opening formed along a movement line of the other member whose relative movement is detected, and said other member. a connecting rod for transmitting the displacement of the object through the opening to a displacement detection mechanism housed inside the hollow case, and a penetrating portion of the connecting rod disposed on both sides of the opening of the hollow case. In the sealing device for a displacement measuring machine having a sealing member for
A liquid receiving groove extending along the opening is provided, and a liquid drainage hole communicating with the outside of the hollow case is provided at the bottom of the liquid receiving groove, and a liquid receiving groove is provided at the bottom of the liquid receiving groove for preventing dust from entering from the outside. A sealing device for a displacement measuring machine characterized by being equipped with a filter. 2. The sealing device for a displacement measuring machine according to claim 1, wherein a liquid barrier is provided in the hollow case between the liquid receiving groove and the displacement detection mechanism. 3. The sealing device for a displacement measuring machine according to claim 2, wherein the liquid barrier is made of an elastic member whose tip is brought into contact with the connecting rod. 4. The sealing device for a displacement measuring machine according to claim 3, wherein a side surface of the liquid receiving groove of the elastic member is sloped to quickly guide invading droplets to the liquid receiving groove. 5. The sealing device for a displacement measuring machine according to claim 1, wherein the drain hole is formed with a thread for screwing a sealing screw into the drain hole. 6. The sealing device for a displacement measuring machine according to claim 1, wherein the sealing member comprises a flexible lip member whose tip end is brought into butt contact with the connecting rod. 7. The sealing device for a displacement measuring machine according to claim 1, wherein the sealing member is a metal band attracted by magnets arranged on both sides of the opening of the hollow case.