JPS63191550A - Sensor for detecting frictional resistance on sliding surface - Google Patents

Abstract

PURPOSE:To detect poor lubricant supply to a sliding surface of a driven body accurately by arranging a movable body to be displaced by the change in a frictional coefficient on a lower sliding surface of the driven body and by detecting the displacement by means of a sensor. CONSTITUTION:When a feed motor 7 is driven in a normal direction for example, a driven body 3 is moved to the left via a feed screw 6 and a nut 4. At this moment, a movable piece 13 arranged under the driven body 3, being pressed against a sliding surface 2 due to the weight of a sensor case 11 and a spring 12, presses a rear spring 14 with frictional resistance inertia to produce a displacement. The movable piece, however, returns to a neutral position in a short period of time if lubrication is normal. If the lubrication is poor, however, a frictional coefficient mu0 between a lower surface 13b of the movable piece and the sliding surface 2 is large and as a result the movable piece 13 is displaced relative to the case 11. The displacement x0 is detected with a displacement measuring instrument 15 and sent to a control device. In this way, poor lubricant supply to the sliding surface of the driven body can be detected accurately to prevent the sliding surface of a machine from being damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sensor for detecting the state of lubrication between a driven body and a sliding surface.

The frictional resistance of the sliding surfaces on which the tables and carriages of conventional machine tools are placed depends on the state of lubricating oil. For this reason, the current state of lubricating oil supply is currently known by checking the operation of the distributor in the piping, the flow of oil in the piping system, etc. Alternatively, a method is used in which the resistance is measured by the current value of the feed motor.

Problems to be Solved by the Invention With the former method of checking the operation and flow, even if it is possible to know the lubricating state, it is difficult to judge whether the required sliding surfaces are actually being lubricated. Furthermore, with the latter method of detecting current values, it was not possible to clearly determine which sliding surface had a lubricant problem.

Means for Solving the Problems A recess 3b in the sliding surface of the lower surface of the driven body 3 is provided so that it can move only in a direction perpendicular to the sliding surface 2 and always applies a force in the direction of the sliding surface. A case member 1) in which a recess 3C is opened on the lower surface, has a bottom parallel to the sliding surface, and has two side surfaces parallel to each other in the direction of movement, and a recess 3 of the case member 1).
C is loaded so as to be movable only in the moving direction of the driven body 3, the upper and lower surfaces are parallel, and the thickness is greater than the depth of the recess, and the length in the moving direction of the driven body 3 is the same as the moving direction of the recess. The moving piece 13 shorter than the length and the recess 3 of the case member 1)
Spring members 14 are interposed on both sides of the movable piece 13 in the direction of movement and hold the movable piece 13 in a neutral position, and spring members 14 are provided on the case member 1) to detect the displacement of the movable piece 13 in the direction of movement. It also includes a displacement meter 15 that outputs a detection signal.

Example Embodiments of the present invention will be described below based on the drawings.

The driven body 3 is slidable on the sliding surface 2 on the head 1 l1
)1. A nut 4 provided on the lower surface of the bed is screwed into a feed screw 6 which is rotatably provided on the bed with a bearing 5.

A feed motor 7 provided on the bed 1 rotates a feed screw 6 via a gear and a belt, thereby moving the bed. On the sliding contact surface 3a of the lower surface of the driven body 3, a detection sensor 1o is provided at at least one location, preferably at two locations separated from each other.
is buried. This detection sensor 10 has a sensor case II connected to a large diameter portion 3b of a stepped cylindrical hole 3b having a large diameter inlet, which is cut perpendicularly to a sliding surface 3a on the lower surface of a driven body 3, and a sensor case II that contacts the sliding surface 3a. The movable piece 13, which will be described later, is always pressed against the sliding surface 2 by a spring 12 inserted into the small diameter hole 3bz, which is fitted so as to be able to slide in the right angle direction without any gap. If the sensor case 1) has a large weight and can be slid reliably, the spring 12 is not necessarily necessary and is not limited to the spring 12. The sensor case 1) has a bottom surface parallel to the sliding surface 2 on the sliding surface 2 side, and a bottom surface parallel to the moving direction of the driven body 3.
A recessed portion 3C is cut out, which has a side surface 3c1 and is long in the direction of movement. A movable piece 13 is fitted into this recess 3C, which is longer than the depth of the recess 3C and can slide with no gap between the opposing 2,000 faces 3c+. The upper and side sliding surfaces of the moving piece 13 are fixed with Teflon or molybdenum having a small coefficient of friction μ by means of surface treatment 5 such as adhesion or embedding. Further, a member made of the same material as the sliding surface 2 is attached to the lower surface, or the moving piece 13 itself is made of the same material.

A spring 14 of the same strength is interposed between the front and rear walls of the recess 3C in the moving direction of the moving piece 13.
is held in a neutral position. The strength of this spring 14 is such that when the friction coefficient/1 o of the sliding surface is a normal value, the moving piece 13 is brought to the neutral position.

Further, a displacement meter 15 that detects the relative position of the movable piece 13 with the sensor case 1), that is, the driven body 3, measures the displacement of the movable piece 13 from the neutral position at right angles to two parallel opposing sides 3c+ of the sensor case 1). The displacement meter 15 is buried in two places on the front and back of the movement direction of the moving piece 13 or one place on one side.
The displacement output is sent to the control device from the lead wire 15a.

In the control device, a circuit is provided that takes out the output of the displacement meter after a certain period of time when a stable output is obtained so as not to detect unstable movement of the moving piece 13 during acceleration/deceleration when the table is moving. An alarm is issued when the detected value exceeds the set value.

Prior to the operation of the working machine, the sliding part is rotated once, and the necessary oil is supplied at the same time as the start-up. When the feed motor 7 is driven in the forward direction, as the feed screw 6 rotates, the driven body 3 is moved through the nut 4.
is moved to the left in the diagram.

Since the moving piece 13 is pressed against the sliding surface 2 by the sum W of the load of the spring 12 and the weight of the sensor case 1), the moving piece 13 has a frictional resistance n with the sliding surface 2 when the table 3 is moved. Due to the force of the spring 14, the rear spring 14 is compressed and displacement occurs, but if the sliding surface is properly lubricated, the moving piece 13 returns to the neutral position due to the force of the spring 14, eliminating the initial lag and being driven. No delay occurs when the movement of the body 3 is stable. However, if the lubrication condition is poor, the friction coefficient μ between the lower surface 13b of the moving piece 13 and the sliding member 2 will decrease. becomes larger. Now, Pj friction coefficient μ between the bottom of the four parts 3C of the sensor case 1) and the Teflon 13a of the moving piece 13, the load of the spring 12, and the sensor case 1)
The load due to the sum of the weights is W.

If the spring constant of the spring 14 is different from K, then Wμ. =Kx.

The moving piece 13 is shifted until a relationship of 10 μW is reached, and moves by xo relative to the sensor case 1).

This moving layer x. is detected by the displacement meter 15, and the lead wire 15
A is sent to the control device. Table 3 in the control unit
Since the circuit is configured so as not to detect unstable movement of the moving piece during acceleration/deceleration, the output is stable for a certain period of time, and when the value becomes larger than the set value, a warning is issued as a lubrication failure.

According to the warning, the refueling time and interval are changed, the machine is reciprocated at low speed, and recovery from the abnormality is confirmed, and if necessary, the operation of the machine is stopped.

Effects As detailed above, the present invention includes a movable piece that causes relative displacement due to a change in the coefficient of friction on the sliding surface of the lower surface of the driven body, and a sensor that detects the amount of displacement. This has the effect of accurately detecting insufficient oil supply to contact surfaces, preventing damage to one member of the sliding surface of the machine, reducing the number of repairs to the machine, and increasing machine operating efficiency.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the mechanical system, FIG. 2 is a longitudinal cross-sectional view of the detection sensor 10, and FIG. 3 is a cross-sectional view taken along A-A vA in FIG. 2. 2...Sliding surface 3...Driven object 10...Detection sensor 1)...Sensor case 13...Moving piece
12.14... Spring 15... Displacement meter

Claims (2)

[Claims] (1) Provided in a recess in the lower sliding surface of a driven object that moves on the sliding surface so that it can move only in a direction perpendicular to the sliding surface and always applies a force in the direction of the sliding surface. a case member having a concave portion opened on the lower surface and having a bottom parallel to the sliding surface and having two side surfaces parallel to the direction of movement; A moving piece that is loaded and whose upper and lower surfaces are parallel, has a thickness greater than the depth of the recess, and whose length in the moving direction of the driven body is shorter than the length of the driven body in the moving direction of the recess, and the moving piece that moves in the recess of the case member. The method includes a spring member that is interposed on each side of the moving piece in the moving direction and holds the moving piece in a neutral position, and a displacement meter that is provided on the case member and that detects the displacement of the moving piece in the moving direction and outputs a detection signal. A friction resistance detection sensor for a sliding surface, which detects relative movement between a driven body and a moving piece. (2) The slide according to claim 1, wherein the contact surface with the recess of the moving piece is made of a material with a small coefficient of friction, and the contact surface with the sliding surface is made of the same material as the sliding surface. Frictional resistance detection sensor on moving surfaces.