Device for measuring output torque of air heat engine

Abstract

The invention discloses an air heat engine output torque measuring device which comprises an air heat engine body, and a flywheel is installed on the air heat engine body. A circular tube is placed at the bottom of the flywheel, is horizontally arranged and is in contact with the bottom edge of the flywheel; two ends of the circular tube are connected with thin ropes, and the other ends of the two thin ropes are respectively connected with drag hooks of the two spring dynamometers; a round pipe is placed on the carrier roller device, and the carrier roller device is connected to the table top of the objective table with the adjustable height. The top, making contact with the flywheel, of the round pipe is connected with a soft cushion layer, and the top, making contact with the round pipe, of the carrier roller device is coated with powdery lubricants. In the measuring process, the pointer of the spring dynamometer is stable and easy to read; the sliding friction force between the flywheel and the round pipe is controlled by controlling the height of the table top of the objective table, and the purpose of adjusting the output torque from zero is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of torque measurement, and in particular to an output torque measurement device for an air heat engine. Background Art

[0002] In the laboratory air heat engine experiment, in order to measure the output power of the air heat engine under different loads, it is necessary to measure the output torque M of the heat engine under different loads. The output torque measurement method used by the existing air heat engine instruments in the laboratory is to hang a torque meter with a certain mass on the flywheel shaft, adjust the friction between the torque meter and the shaft by adjusting the screw, and finally directly read the friction torque M from the position of the torque meter pointer.

[0003] During the measurement process, the pointer of the torque meter vibrates greatly and cannot be stabilized, causing large errors in the torque measurement; the torque meter itself has a certain mass, which makes it impossible to completely remove the load on the flywheel and the output torque cannot be adjusted from zero.

[0004] Therefore, it is necessary to design a new air heat engine output torque measurement device to solve the problems of unstable readings and the inability of the torque measurement range to start from zero. Summary of the invention

[0005] The purpose of the present invention is to provide an output torque measuring device for an air heat engine. During the measurement process, the pointer of the spring dynamometer is stable and easy to read. By controlling the height of the stage, the sliding friction between the flywheel and the circular tube is controlled, and the output torque can be adjusted from zero, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: An air heat engine output torque measuring device comprises an air heat engine body, on which a flywheel is installed; a lightweight round tube is placed at the bottom of the flywheel, the round tube is arranged horizontally and contacts the bottom edge of the flywheel; thin ropes are connected to both ends of the round tube, and the other ends of the two thin ropes are respectively connected to the hooks of two spring dynamometers; the round tube is placed on a roller device, and the roller device is connected to the table top of a height-adjustable loading platform; a soft cushion layer is connected to the top of the round tube in contact with the flywheel, and a powdered lubricant is coated on the top of the roller device in contact with the round tube.

[0007] A further solution of the present invention is that the round tube is a plastic tube with a smooth outer surface, both ends of the round tube are connected with cylindrical plugs, and two thin ropes are connected to the plugs.

[0008] A further solution of the present invention is that, in theoretical design, the table surface below the round tube is ideally smooth and does not generate friction, but in reality there is non-negligible friction between them. In order to eliminate the influence of this friction as much as possible, a double-wheel fixed pulley is added between the round tube and the table surface of the stage, and talcum powder is applied on the two wheels to increase the degree of lubrication and reduce the friction resistance as much as possible. When placed, the double-wheel fixed pulley and the flywheel need to be placed in the same plane, and the tops of the two wheels are in a horizontal state, so that the pressure applied by the round tube to the flywheel is in a vertical direction and just passes through the rotating shaft of the flywheel.

[0009] A further solution of the present invention is to achieve the output torque adjustment: Sliding friction force f is defined as: ; Among them, μ is the sliding friction coefficient at the contact position; N is the normal pressure at the contact position.

[0010] In the measuring device, the height of the stage is changed by adjusting the adjusting screw under the stage, thereby changing the positive pressure between the round tube and the edge of the flywheel, thereby achieving the adjustment of the sliding friction force.

[0011] Because the force between the adjustment screw and the screw hole under the stage is not strong enough, the adjustment screw rotates automatically due to vibration during the operation of the air heat engine, which causes the stage to automatically drop, and eventually the sliding friction force decreases continuously. To this end, a vibration isolation spring is added to each adjustment screw to increase the force between the adjustment screw and the screw hole to solve the problem of the stage automatically sliding down.

[0012] A further solution of the present invention is that two mounting brackets are provided at both ends of the air heat engine body, an upper adjustment seat and a lower adjustment seat are connected to the column of each mounting bracket, a hook is connected to the bottom of the upper adjustment seat, and a spring dynamometer is vertically hung on the hook.

[0013] A further solution of the present invention is that a single-wheel fixed pulley is connected to the lower adjustment seat, and one end of the thin rope passes through the wheel of the single-wheel fixed pulley and changes direction by 90 degrees before being connected to a hook at the bottom end of the spring dynamometer.

[0014] A further solution of the present invention is that, since it is difficult to ensure that the rotation center of the flywheel is completely coincident with the center of the flywheel circle, and the flywheel surface cannot be completely perpendicular to the air heat engine shaft, the friction coefficient at each edge of the flywheel cannot be completely the same. This will cause the friction coefficient and positive pressure between the round tube and the flywheel to change slightly during the rotation process, the elastic force on the string will be larger or smaller, and the dynamometer pointer will shake abnormally and cannot read.

[0015] To this end, a cushion layer is covered on the upper surface of the circular tube, that is, the side where the circular tube contacts the edge of the flywheel. The cushion layer is made of cotton cloth of moderate thickness, and the thickness of the cushion layer is 0.8 to 1.2 mm, preferably 1 mm, to reduce the variation range of the friction coefficient and the normal pressure, so that the generated sliding friction force becomes more stable and solve the problem of abnormal jitter of the spring dynamometer pointer.

[0016] A further solution of the present invention is that the bottom end of the thin rope is arranged concentrically with the circular tube.

[0017] Beneficial effects of the present invention: ①. During the measurement process, the pointer of the spring dynamometer is stable and easy to read; ②. By controlling the height of the stage, the sliding friction between the flywheel and the round tube is controlled to achieve the purpose of adjusting the output torque from zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0019] Figure 2 It is a schematic diagram of the local structure of the present invention.

[0020] Figure 3 Schematic diagram a of the friction force measurement principle in the present invention and schematic diagrams of the forces before (b) and after (c) the friction force is generated.

[0021] In the figure: 1-air heat engine body, 101-flywheel, 102-base, 2-round tube, 201-plug, 3-thin rope, 4-spring dynamometer, 5-double-wheel fixed pulley, 6-loading platform, 601-table, 602-adjusting screw, 603-vibration isolation spring, 7-cushion, 8-mounting bracket, 801-column, 802-upper adjustment seat, 803-lower adjustment seat, 9-single-wheel fixed pulley. DETAILED DESCRIPTION

[0022] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments.

[0023] Example 1: Figures 1-2 As shown, an air heat engine output torque measuring device comprises an air heat engine body 1, on which a flywheel 101 is installed; a round tube 2 is placed at the bottom of the flywheel 101, the round tube 2 is horizontally arranged and contacts the bottom edge of the flywheel 101; thin ropes 3 are connected to both ends of the round tube 2, and the other ends of the two thin ropes 3 are respectively connected to the hooks of two spring dynamometers 4; the round tube 2 is placed on a roller device, and the roller device is connected to a table 601 of a height-adjustable loading platform 6; a soft cushion layer 7 is connected to the top of the round tube 2 in contact with the flywheel 101, and a powdered lubricant is coated on the top of the roller device in contact with the round tube 2.

[0024] The round tube 2 is a plastic tube with a smooth outer surface and uniform thickness. The mass of the round tube does not exceed 5 grams and the length is 7.5 cm. Both ends of the round tube 2 are connected with cylindrical plugs 201, and two thin ropes 3 are connected to the plugs 201.

[0025] The roller device is a double-wheel fixed pulley 5, which is connected to the table 601, and the round tube 2 is placed in the wheel grooves of the two wheels of the double-wheel fixed pulley 5, and the powdered lubricant is applied to the two wheels.

[0026] The loading platform 6 is connected to the base 102 of the air heat engine body 1 . An adjusting screw 602 for adjusting the height of the table 601 is connected to the loading platform 6 . A vibration isolation spring 603 is sleeved on the adjusting screw 602 .

[0027] Two mounting brackets 8 are provided at both ends of the air heat engine body 1. An upper adjustment seat 802 and a lower adjustment seat 803 are connected to the column 801 of each mounting bracket 8. A hook is connected to the bottom of the upper adjustment seat 802, and a spring dynamometer 4 is vertically hung on the hook.

[0028] A single-wheel fixed pulley 9 is connected to the lower adjustment seat 803 , and one end of the thin rope 3 passes through the wheel of the single-wheel fixed pulley 9 and changes direction by 90° before being connected to the hook at the bottom end of the spring dynamometer 4 .

[0029] The bottom end of the string 3 is arranged concentrically with the circular tube 2 .

[0030] The cushion layer 7 is made of cotton cloth, which is bonded to the upper surface of the round tube 2 .

[0031] The thickness of the cushion layer 7 is 1 mm.

[0032] The powdered lubricant is talcum powder.

[0033] The sliding friction force of the edge of the flywheel 101 along the tangential direction is measured using two spring dynamometers 44, and the output torque is obtained by the radius of the flywheel 101. Figure 3 As shown in a. Two spring dynamometers 44 pull the round tube 2 horizontally, and place the round tube 2 between the smooth table 601 and the flywheel 101. The two spring dynamometers 44 and the round tube 2 are in the same horizontal straight line and remain stationary.

[0034] When the tube 2 just touches the edge of the flywheel 101 but does not generate sliding friction, the tube 2 is acted upon by the following four forces: left and right spring dynamometers 44F 左 、F 右 The initial tensile force F is applied 左0 、F 右0 , the gravity G of the tube 2 itself, the vertical upward support force N applied to the tube 2 by the smooth table 601, and the force diagram of the tube 2 is as follows: Figure 3As shown in b. Since the circular tube 2 is in a balanced state, the resultant forces in the horizontal and vertical directions are both zero, that is: ; When sliding friction is generated between the tube 2 and the edge of the flywheel 101, assuming that the flywheel 101 rotates clockwise, the flywheel 101 will apply a leftward sliding friction force f to the tube 2. At this time, the forces on the tube 2 are as follows: the tension F applied by the left and right spring dynamometers 44 respectively 左 and F 右 , the sliding friction force f applied by the flywheel 101, the self-gravity G, the vertical downward elastic force N1 applied by the flywheel 101 to the round tube 2, and the vertical upward elastic force N applied by the smooth table 601. The force diagram is shown in Figure 3 c. When the system is in a stable state, the circular tube 2 is in a stationary state. Therefore, the circular tube 2 reaches force balance in both the horizontal and vertical directions, and the resultant force is zero. That is: ; Therefore, the sliding friction force applied by the flywheel 101 to the round tube 2 is: ; From the sliding friction force f given by equation (5) and the rotation radius R of the flywheel 101, the output torque M of the heat engine can be obtained as: .

[0035] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. An air heat engine output torque measuring device, comprising an air heat engine body (1), a flywheel (101) being mounted on the air heat engine body (1); characterized in that: A circular tube (2) is placed at the bottom of the flywheel (101), the circular tube (2) being arranged horizontally and in contact with the bottom edge of the flywheel (101); thin ropes (3) are connected to both ends of the circular tube (2), the other ends of the two thin ropes (3) being respectively connected to the hooks of two spring dynamometers (4); the circular tube (2) is placed on a roller device, and the roller device is connected to a table surface (601) of a height-adjustable loading platform (6); a soft cushion layer (7) is connected to the top of the circular tube (2) in contact with the flywheel (101), and a powdered lubricant is applied to the top of the roller device in contact with the circular tube (2).

2. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: The circular tube (2) is a plastic tube with a smooth outer surface. Both ends of the circular tube (2) are connected to cylindrical plugs (201), and two thin ropes (3) are connected to the plugs (201).

3. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: The roller device is a double-wheel fixed pulley (5), the double-wheel fixed pulley (5) is connected to the table (601), the round tube (2) is placed in the wheel grooves of the two wheels of the double-wheel fixed pulley (5), and the powdered lubricant is applied to the two wheels.

4. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: The loading platform (6) is connected to the base (102) of the air heat engine body (1), and an adjusting screw (602) for adjusting the height of the table surface (601) is connected to the loading platform (6), and a vibration isolation spring (603) is sleeved on the adjusting screw (602).

5. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: Two mounting brackets (8) are provided at both ends of the air heat engine body (1); an upper adjustment seat (802) and a lower adjustment seat (803) are connected to the upright column (801) of each mounting bracket (8); a hook is connected to the bottom of the upper adjustment seat (802), and a spring dynamometer (4) is vertically hung on the hook.

6. The device for measuring the output torque of an air heat engine according to claim 5, characterized in that: The lower adjustment seat (803) is connected to a single-wheel fixed pulley (9), and one end of the thin rope (3) passes through the wheel of the single-wheel fixed pulley (9), changes direction by 90 degrees, and is then connected to a draw hook at the bottom end of the spring dynamometer (4).

7. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: The bottom end of the thin rope (3) is arranged concentrically with the circular tube (2).

8. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: The cushion layer (7) is made of cotton cloth, which is bonded to the round tube (2).

9. The device for measuring the output torque of an air heat engine according to claim 1, characterized in that: The cushion layer (7) has a thickness of 0.8 to 1.2 mm.

10. The device for measuring output torque of an air heat engine according to claim 1, characterized in that: The powdery lubricant is talcum powder.

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