CN207751429U - A device for measuring the inclination angle of the mortise and groove of the engine compressor wheel - Google Patents

Abstract

The utility model provides an engine compressor wheel disc tongue-and-groove inclination angle measuring device, which comprises an adapter, a bridge type measuring tool and a dial indicator, wherein the bridge type measuring tool comprises a measuring tool body, one end of the measuring tool body is provided with a positioning reference surface, a dial indicator mounting hole is arranged in the middle of the measuring tool body, the dial indicator is fixed on the measuring tool body through the dial indicator mounting hole, and a measuring rod of the dial indicator is vertical to the positioning reference surface; and a measuring space is arranged below the dial indicator mounting hole and can be used for accommodating a measuring plane of the adapter. The engine compressor wheel disc mortise inclination angle measuring device can keep the stability and the continuity of the matching of the positioning reference surface and the upper end surface of the engine compressor wheel disc, improves the measuring stability, further can reduce the measuring times and improve the measuring efficiency.

Description

A device for measuring the inclination angle of the mortise and groove of the engine compressor wheel

technical field

The utility model belongs to the technical field of mechanical manufacturing, and relates to a device for measuring the inclination angle of a wheel disc of an engine compressor.

Background technique

In order to make the aero-engine compressor disk withstand a lot of stress in the high-speed working environment and ensure the uniform distribution of the load transmitted by the blades, there are strict requirements on the size, angle and technical conditions for the blades to be inserted into the tenon grooves of the compressor disk. Require. Due to the processing technology, the inclination angle of the tenon and groove of the wheel disc cannot be exactly the same. In order to control the difference in inclination angle of the tenon and groove of the wheel disc, in addition to process control, it is also necessary to accurately measure the inclination angle of the tenon and groove of the wheel disc to ensure that the tenon and groove The tilt angle meets the control requirements. At present, an adapter is used in combination with a lever dial indicator to push the meter to measure, and the difference displayed by the hands is the measurement result. Since the width of the measurement reference plane (compressor disc spoke) is less than 1/2 of the base width of the universal meter frame, the measurement stability is not good, and there is a possibility of false detection. In order to prevent false detection, multiple measurements are taken, and the measurement efficiency is low, and There is also the possibility of false detection.

Utility model content

The purpose of the utility model is to provide a device for measuring the inclination angle of the tenon and groove of the wheel disk of the engine compressor, which can quickly and accurately measure the inclination angle of the tenon and groove of the wheel disk.

The utility model is realized through the following technical solutions:

A device for measuring the inclination angle of the wheel disk of an engine compressor, including an adapter, a bridge measuring tool and a dial indicator, wherein,

The adapter includes an adapter body and two tapered rods. The adapter body includes a positioning part, a connecting plate and a measuring part; the rear side of the positioning part can be fitted with the bottom surface of the tongue and groove, and the front side of the positioning part is set in the middle Connecting plate, the connecting plate is in the same extension direction as the positioning part, and the connecting plate is connected to the rear side of the measuring part; the top of the positioning part has a positioning pin, and the positioning pin can be combined with the upper end surface of the engine compressor wheel; The lower end is inserted into the tenon groove, and fits with the front side of the positioning part, the side wall of the tenon groove and the side wall of the connecting plate, and the two tapered rods are respectively located on both sides of the connecting plate; When the connector is installed on the engine compressor wheel whose inclination angle of the mortise is exactly the set angle, the measurement plane is parallel to the upper end surface of the engine compressor wheel;

The bridge measuring tool includes a measuring tool body, one end of the measuring tool body has a positioning reference plane, and a dial indicator mounting hole is set in the middle, and the dial indicator is fixed on the measuring tool body through the dial indicator mounting hole, and the measuring rod of the dial indicator is connected with the measuring rod. The positioning reference plane is vertical; a measurement space is set under the dial indicator installation hole, and the measurement space can accommodate the measurement plane.

Preferably, the bridge measuring tool further includes a watch clip and a watch clip nut; the watch clip is fixed in the dial indicator installation hole, and the dial indicator is fixedly connected to the watch clip through the watch clip nut.

Preferably, the adapter further includes a handle, which is detachably fixed on the front side of the measuring part.

Preferably, the measurement plane has a width of 20 mm in a direction perpendicular to the radial direction of the engine compressor wheel.

Preferably, both ends of the measuring tool body have positioning datum surfaces.

Preferably, there is a protruding part in the middle of the measuring tool body, and a measuring space is set under the protruding part.

Compared with the prior art, the utility model has the following beneficial technical effects:

The utility model provides a device for measuring the inclination angle of the tenon and groove of the engine compressor disc, which includes an adapter, a bridge measuring tool and a dial indicator, wherein the adapter is used to cooperate with the tenon and groove and provide a measurement plane, and the dial indicator Measure the height deviation of the measurement plane, and calculate the deviation between the inclination angle of the tenon and groove and the actual value, and then calculate the inclination angle of the tenon and groove. Among them, the utility model does not use a general-purpose meter frame, but a bridge-type measuring tool is specially designed. The middle of the bridge-type measuring tool is used to install the dial indicator, and the end of the bridge-type measuring tool is provided with a positioning reference plane, which is used to connect with the engine compressed air. The upper end face of the machine wheel is matched, and under the condition of keeping the fit, the bridge measuring tool is moved to drive the dial gauge to measure the height deviation of the measuring plane. Because the bridge measuring tool only needs to cooperate with the upper end surface of the engine compressor wheel through the positioning datum plane, and does not need to match the entire lower side of the bridge measuring tool with the upper end surface of the engine compressor wheel, the stability and stability of the matching can be maintained. Continuity improves the stability of measurement, which in turn can reduce the number of measurements and improve measurement efficiency.

Description of drawings

Fig. 1-1 is a front structural schematic diagram of the tongue and groove inclination angle measuring device of the present invention.

Fig. 1-2 is a top view structure schematic diagram of the mortise and groove inclination angle measuring device of the present invention.

Fig. 2-1 is a schematic front view of the combination of the bridge measuring tool and the dial indicator of the present invention.

Fig. 2-2 is a schematic top view of the combination of the bridge measuring tool and the dial indicator of the present invention.

Fig. 3-1 is a schematic top view of the adapter of the present invention.

Figure 3-2 is a schematic diagram of the side view of the adapter of the present invention.

Fig. 3-3 is a schematic cutaway diagram of A-A in Fig. 3-1.

Fig. 3-4 is a structural schematic diagram of the adapter of the present invention, which mainly reflects the structure of the front side of the measuring part.

Figure 4-1 is a schematic diagram of the front view of the bridge measuring tool body of the present invention.

Fig. 4-2 is a schematic top view of the bridge measuring tool body of the present invention.

Fig. 5 is a schematic diagram of the watch holder.

Fig. 6 is a schematic diagram of a clamp nut.

Fig. 7-1 is a schematic side view of the adapter body of the present invention.

Fig. 7-2 is a schematic cut-away diagram of B-B in Fig. 7-1.

Fig. 7-3 is a schematic diagram of the structure of the adapter body of the present invention, which mainly reflects the structure of the front side of the measuring part.

Fig. 8 is a schematic diagram of a positioning pin.

Figure 9 is a schematic diagram of a tapered rod.

Figure 10 is a schematic diagram of the handle.

Figure 11-1 is a schematic top view of the engine compressor wheel.

Figure 11-2 is a schematic side view of the engine compressor wheel.

Fig. 12-1 is a principle diagram of converting angle deviation value measurement into height deviation value measurement in the utility model.

Fig. 12-2 is a schematic diagram of converting angle deviation value measurement into height deviation value measurement in the utility model, and is a partially enlarged view at NP in Fig. 12-1.

Among them: 1 is the engine compressor wheel; 11 is the tongue and groove; 12 is the upper end surface of the engine compressor wheel; 2 is the adapter, 211 is the positioning part; 212 is the connecting plate; 213 is the measuring part; 214 is the cone Rod; 215 is the handle; 216 is the positioning pin; 3 is the bridge measuring tool; 31 is the measuring tool body; 311 is the protruding part; 312 is the foot part; 313 is the reinforcing rib; ; 4 is a dial indicator.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail:

In the present utility model, the concepts of front, back, up and down are used, such as "the rear side of the positioning part", etc. Those skilled in the art should know that the limitations of these orientations describe the relative relationship between different components or structures. Positional relationships, rather than absolute spatial relationships. When describing these positional relationships, the description reference system used is as follows: take the upper side or upper end surface of the engine compressor wheel 1 as the top, and vice versa; along the radial direction of the engine compressor wheel 1, point to the direction of the center of the circle is the rear, and the direction away from the center of circle is the front (that is, the inner side of the engine compressor wheel disc 1 is the rear, and the outer side is the front). For the tenon groove 11 , the concept of the bottom surface of the tenon groove 11 is also used. The bottom surface of the tenon groove 11 is a conventional concept, and its direction is relative to the opening of the tenon groove 11 . Correspondingly, left and right are also used as limitations in the present invention. Obviously, the left and right direction is the direction perpendicular to the plane formed by the front, rear, left, and right directions, and the up and down direction is maintained. The left side viewed from front to back is the left direction, and the right side is the right direction. direction.

Example 1

The utility model provides a device for measuring the inclination angle of the tenon and groove of the engine compressor wheel, wherein the inclination angle of the tenon and groove of the engine compressor wheel (as shown in Figure 11-1 and Figure 11-2) is designed to be 65° , with an error of no more than 5 points. In order to measure the angle of inclination of the tenon and groove 11, the measuring device for the angle of inclination of the engine compressor wheel disk provided by the utility model includes: an adapter 2, a bridge measuring tool 3 and a dial indicator 4, wherein,

The adapter 2 includes an adapter body, a handle 215 and two tapered rods 214 , wherein the adapter body includes a positioning portion 211 , a connecting plate 212 and a measuring portion 213 .

As shown in Figure 3-1, Figure 3-2, Figure 3-3, Figure 3-4, Figure 7-1, Figure 7-2 and Figure 7-3, the rear side of the positioning part 211 can be aligned with the tongue and groove 11 The bottom surface is attached, and a connecting plate 212 is arranged in the middle of the front side of the positioning part 211. The connecting plate 212 is consistent with the extending direction of the positioning part 211, and the connecting plate 212 is connected to the rear side of the measuring part 213;

In this way, the positioning part 211 can be inserted into the tenon groove 11 from the upper end of the tenon groove 11, the rear side of the positioning part 211 can be attached to the bottom surface of the tenon groove 11, and its top end has a positioning pin 216 (as shown in Figure 8), and the positioning pin 216 It can be combined with the upper end surface 12 of the engine compressor wheel to realize the positioning of the adapter in the axial direction (ie, up and down) of the engine compressor wheel 1; The measuring portion 213 outside the tongue and groove 11 is connected. The upper end face of the measuring portion 213 is a measuring plane, and when the inclination angle of the tenon groove 11 is exactly 65°, the measuring plane is parallel to the upper end face 12 of the engine compressor wheel.

When in use, insert the positioning part 211 from the upper end surface of the tenon groove 11 of the engine compressor wheel disc into the tenon groove 11 whose theoretical inclination angle is 65°, until the positioning pin 216 on the positioning part 211 and the engine compressor wheel disc The end face 12 fits together without any gap, and the rear side of the positioning part 211 fits with the bottom surface of the tongue and groove 11 . At this time, the connecting plate 212 passes through the opening at the front end of the tenon groove 11 to fix the measuring part 213 in front of the side of the engine compressor wheel 1 outside the tenon groove 11 . As shown in Figure 3-2, insert the two tapered rods 214 (as shown in Figure 9) from the lower end of the tenon groove 11 into the gap between the positioning part 211 and the tenon groove 11, and use light force to make the two tapered rods 214 close to each other. The outer side of the positioning part 211 , the side of the connecting plate 212 and the side wall of the tenon groove 11 make the positioning part 211 closely fit on the tenon and groove 11 without any gap. When inserting the tapered rods 214, two tapered rods 214 are respectively inserted into both sides of the connecting plate 212 to ensure that the extending direction of the positioning part 211 is consistent with the extending direction of the tenon groove 11 and ensure the accuracy of angle measurement of the tenon groove 11.

When installing the adapter 2, there should be no sticking phenomenon. If so, check whether the parts have appearance defects, etc., and eliminate them. Check the insertion length of the two tapered rods 214, the length must exceed one-half of the thickness of the tenon groove 11, the exposed length of the two tapered rods 214 must be basically consistent, if not, check whether the various parts of the device are installed correctly, etc., and eliminate .

A handle 215 (as shown in FIG. 10 ) is connected to the front side of the measuring part 213 through a threaded hole, so as to facilitate the installation and removal of the adapter 2 .

As shown in FIG. 2-1 and FIG. 2-2 , the bridge measuring tool 3 includes a measuring tool body 31 , a clip 32 and a clip nut 33 . As shown in Fig. 4-2 and Fig. 4-2, the measuring tool body 31 is bridge type, and its two ends are leg parts 312, and the leg parts 312 all have a positioning reference plane, and there is a protruding part 311 in the middle, and the protruding part 311 is below Set up the measurement space. Protruding part 311 is provided with dial indicator installation hole, and dial indicator installation hole cooperates with table holder 32 (as shown in Figure 5), and table holder 32 is used for installing dial indicator 4, table holder nut 33 (as shown in Figure 6). (shown) fix the dial gauge 4 on the watch holder 32; where, after the dial gauge 4 is installed, the measuring rod of the dial gauge 4 is perpendicular to the positioning datum plane of the measuring tool body 31. A reinforcing rib 313 is also provided on the measuring tool body 31 , and the reinforcing rib 313 is used to connect the leg portion 312 and the protruding portion 311 . In a feasible solution, the width of the leg portion 312 is not greater than twice the spoke of the compressor wheel, preferably not greater than the spoke of the compressor wheel, so that the positioning reference plane can be aligned with the upper end surface 12 of the engine compressor wheel (measured base level) for a stable combination.

As shown in Figure 1-1 and Figure 1-2, during application, the adapter 2 is installed on the engine compressor wheel 1, and a positioning reference plane of the measuring tool body 31 is aligned with the upper end surface 12 of the engine compressor wheel Always keep fit, the dial indicator 4 moves from one side to the other at the left and right ends of the measurement plane, take the starting position as the "0" point of the dial indicator 4, and read the reading of the dial indicator 4 at the end position, Find out the inclination angle of the corresponding tongue and groove 11 according to the pre-made conversion table.

Example 2

The utility model provides a device for measuring the inclination angle of the mortise 11 of the engine compressor disc, based on the embodiment 1, consisting of an adapter 2, a dial indicator 4, and a bridge measuring tool 3, as shown in Figure 1- 1 and Figure 1-2, the measurement steps are:

1) As shown in Figure 2-1 and Figure 2-2, the dial indicator 4 is installed into the bridge measuring tool 3.

2) The adapter 2 is limited and fixed in the tongue and groove 11 .

3) Put the bridge measuring tool 3 with the dial indicator 4 on the upper end surface 12 of the engine compressor wheel, and confirm the "0 point" of the dial indicator 4 on the measuring plane of the adapter 2.

4) According to the requirements of the inclination angle of the tenon and groove of the engine compressor wheel disc, convert the table value of the allowable change in the inclination angle of the tenon and groove within the range of 20mm in the measurement length.

Conversion method: as shown in Figure 12-1, MM' is the inclined line of the designed tenon and groove 11, α is the inclination angle of the tenon and groove of the engine compressor wheel, NN' is the actual inclined line of the tenon and groove, and the corresponding engine compressor The inclination angle of the tenon and groove of the machine wheel is α+Δα; according to the partially enlarged schematic diagram of Figure 12-1 shown in Figure 12-2, the angular tolerance Δα on the 20mm length NP' is converted into a linear tolerance Δh(PP'), that is, the table value Displayed altitude difference. Use trigonometric functions to convert the angle tolerance into a height value Δh, Δh=20sinΔα, where Δα is half of the absolute value of the difference between the upper deviation and the lower deviation of the inclination angle of the tongue and groove, that is, Δα=|upper deviation-lower deviation|/ 2.

5) Move the bridge measuring tool 3 with the dial indicator 4, make the measuring plane of the dial indicator 4 fit the adapter 2, measure the length of the plane to 20 mm, observe the indication change of the dial indicator 4 during the process, and pass The change difference judges whether the inclination angle of the tenon and groove of the engine compressor wheel is qualified, and the deviation value and angle value of the inclination angle of the tenon and groove are obtained after conversion.

Conversion method: Convert the linear value on the 20mm length into an angular value, that is, the actual angular deviation. Use trigonometric functions to convert the height value into an angle deviation value Δα, that is, Δα=arcsin(Δh/20); the sum of the deviation value and the theoretical angle is the inclination angle value A of the tenon and groove, that is, A=α+Δα, where α is the tenon and groove 11 Theoretical tilt angle, ie 65°.

Wherein, in order to facilitate the operation, the width of the measuring plane of the adapter 2 is 20mm, that is, the measuring head of the dial indicator 4 is moved from one end of the measuring plane to the other end (left and right direction), so that the dial indicator 4 can measure 20mm Height tolerance Δh on length.

The utility model has simple structure, and the whole measuring device only needs to manufacture seven kinds of parts. Measurement accuracy, repeatability, and reproducibility can meet product control requirements, and there is no risk of false detection. Easy to operate, just move the bridge measuring tool 3 lightly during operation, and the measurement is stable.

The tenon and groove inclination angle measuring device provided by the utility model is composed of an adapter 2, a bridge measuring tool 3 and a dial indicator 4.

Wherein, the bridge measuring tool 3 is composed of a body, a watch clip 32, and a watch clip nut 33 as shown in Figure 2;

Make parts:

1) The main component of the bridge-type measuring tool 3 is the measuring tool body 31, as shown in Figure 4-1 and Figure 4-2, on which a threaded hole of M12X1 is processed; a watch clip 32 of M12X1-7h HB2025-89 is processed As shown in Fig. 5), process a clip nut 33 of M12X1-6H HB2023-89 (as shown in Fig. 6).

2) The main component of the adapter 2 is the adapter body, on which a pin hole and a threaded hole are processed, a positioning pin 216 is processed (as shown in Figure 8), two tapered rods 214 are processed (as shown in Figure 9), and processed A handle 215 (as shown in Figure 10).

Assembly:

1) Screw in the watch clip 32 on the measuring tool body 31, and screw on the watch clip nut.

2) Install a positioning pin 216 and a handle 215 on the adapter body.

Take the engine compressor wheel 1 as shown in Figure 11-1 and Figure 11-2 as an example with the theoretical inclination angle of the tongue and groove being 65°±5':

Prepare:

1) Put the dial indicator 4 into the bridge measuring tool 3, tighten the clamp nut 33, check the stability of the indication value of the dial indicator 4, and watch whether the pointer can return to the original position. If the pointer cannot return to the original position, replace the dial indicator. Sub-meter 4 until the dial indicator 4 meets the requirements.

2) Insert the adapter 2 from the upper end surface of the tenon groove 11 of the compressor into the tenon groove 11 of the compressor disk with a theoretical inclination angle of 65° until the positioning pin 216 on the adapter 2 is attached to the upper surface of the compressor disk wheel rim There is no gap, the reference surface of the adapter 2 (the rear side of the positioning part 211) is attached to the bottom surface of the tenon groove 11, and then the two tapered rods 214 are inserted from the lower end of the compressor tenon groove 11 between the adapter 2 and the tenon groove 11 Use light force to make the two tapered rods 214 close to the adapter 2 and the tenon groove 11, so that the adapter 2 fits tightly on the tenon groove 11 of the compressor plate without any gap. When installing the adapter 2, there should be no sticking phenomenon. If so, check whether the parts have appearance defects, etc., and eliminate them. Check the insertion length of the two tapered rods 214, the length must exceed one-half of the thickness of the tenon groove 11 of the compressor, and the exposed length of the two tapered rods 214 must be basically consistent, if not, check whether each part of the device is installed correctly, etc. and exclude.

3) Put the positioning reference of the bridge measuring tool 3 with the dial indicator 4 on the end face of the compressor disk, adjust the compaction amount of the dial indicator 4, which is generally 5 times the height difference of the angle conversion, and the tenon groove 11 is inclined The angle is 65°±5′, and the converted height difference is 0.03mm, that is, Δh=20*sinα=20*sin5′=0.03(mm). See Table 1 for the table values converted from the inclination angles of the mounting grooves of all levels of roulette. Right end of the measurement plane), confirm dial indicator 4 "0 point". According to Table 1, it can be known that although the utility model uses the roulette required by the drawings as 65°±5′ as an example, for the roulettes whose inclination angles of the tongue and groove 11 required by the drawings are other values, as long as they are matched with an appropriate adapter 2 , the measurement purpose can still be achieved.

Table 1: Conversion table of inclination angles of mortise and groove of all levels of roulette

Measurement: continue to take the 65°±5′ roulette required by the drawing as an example, move the bridge measuring tool 3 with the dial indicator 4, and always make the bridge measuring tool 3 with the dial indicator 4 locate the datum plane and the compressor The upper end face of the disc rim is attached, and the measured surface of the adapter 2 is pushed along the linear direction to measure. During this process, the indication change of the dial indicator 4 within the range of 20mm is observed, and the change amount is the linear difference of the inclination angle of the tenon and groove. , the inclination angle value of the tenon and groove is obtained through conversion, and the change is 0.03mm. The inclination angle value of the groove is 65°5', that is, A=α+Δα=65°+5'=65°5', and the angle value converted from the linear difference of the inclination angle of the 65° tongue and groove is shown in Table 2. When measuring for the first time, one tenon and groove 11 can be measured 2-3 times, and when the error of each measurement value is not greater than 1/3 of the required value, the device is considered to be stable, otherwise, it needs to be checked until it is stable. Next, repeat the above method to detect parts. Table 2: 65°±5′ mortise inclination angle conversion table

Indicator change (mm) Angle deviation value after conversion Converted angle value -0.03 -5′ 64°55′ -0.02 -3′ 64°57′ -0.01 -1' 64°59′ 0 0' 65° +0.01 +1' 65°1′ +0.02 +3′ 65°3′ +0.03 +5′ 65°5′

Claims (6)

1. a kind of engine compressor wheel disc chase mortise tilt angle measuring apparatus, which is characterized in that surveyed including adapter (2), bridge-type Have (3) and dial gauge (4), wherein

Adapter includes adapter body and two tapered rods (214), and adapter body includes positioning region (211), connecting plate (212) and measurement portion (213)；The trailing flank of positioning region (211) can be bonded with the bottom surface of tongue-and-groove (11), before positioning region (211) Setting connecting plate (212) among side, connecting plate (212) is consistent with positioning region (211) extending direction, connecting plate (212) and survey The trailing flank in amount portion (213) connects；Positioning region (211) top has positioning pin (216), and positioning pin (216) can be with engine Compressor disk upper surface (12) combines；Tapered rod (214) can be inserted into from tongue-and-groove (11) lower end in tongue-and-groove (11), and and positioning region (211) leading flank, tongue-and-groove (11) side wall and connecting plate (212) side wall is bonded, and two tapered rods (214) are located at connecting plate (212) both sides；The upper surface of measurement portion (213) is to measure plane, when the inclination angle that adapter (2) is installed to tongue-and-groove (11) is proper When on the engine compressor wheel disc (1) of set angle, it is parallel with engine compressor wheel disc upper surface (12) to measure plane；

Bridge-type measuring tool (3) includes measuring tool ontology (31), and one end of measuring tool ontology (31) has positioning reference plane, centre setting percentage Table mounting hole, dial gauge (4) is fixed on measuring tool ontology (31) by dial gauge mounting hole and the gauge rod of dial gauge (4) and positioning Reference plane is vertical；Setting measures space below dial gauge mounting hole, and measurement plane can be housed by measuring space.

2. engine compressor wheel disc chase mortise tilt angle measuring apparatus as described in claim 1, which is characterized in that the bridge-type Measuring tool (3) further includes table folder (32) and table folder nut (33)；Table folder (32) is fixed in dial gauge mounting hole, and dial gauge (4) is logical Table folder nut (33) is crossed to be fixedly connected with table folder (32).

3. engine compressor wheel disc chase mortise tilt angle measuring apparatus as described in claim 1, which is characterized in that the switching Device (2) further includes handle (215), and handle (215) is removably attached to the leading flank of measurement portion (213).

4. engine compressor wheel disc chase mortise tilt angle measuring apparatus as described in claim 1, which is characterized in that measure plane It is 20mm in the width perpendicular to engine compressor wheel disc (1) radial direction.

5. engine compressor wheel disc chase mortise tilt angle measuring apparatus as described in claim 1, which is characterized in that measuring tool ontology (31) both ends all have positioning reference plane.

6. engine compressor wheel disc chase mortise tilt angle measuring apparatus as described in claim 1, which is characterized in that measuring tool ontology (31) intermediate that there is protrusion (311), protrusion (311) following settings to measure space.