Floating Z-axis device for air pressure regulation of air circuit and its control method

Abstract

An embodiment of the present invention discloses a floating Z-axis device for air pressure regulation and its control method. The device includes an R-axis mechanism, a Z-axis, and an air pressure regulation mechanism. An axial cavity corresponding to the Z-axis is provided inside the R-axis mechanism, and the Z-axis is floatingly arranged in the axial cavity. The air pressure regulation mechanism includes a pressure regulation air path and a switching valve. A pressure regulation valve for adjusting the air pressure in the axial cavity and a pressure sensor for detecting the air pressure in the axial cavity are provided in the pressure regulation air path. The axial cavity is connected to an external positive pressure air source or a negative pressure air source through the pressure regulation air path, and the switching valve is used to switch the connection of the axial cavity to the external positive pressure air source or the negative pressure air source. The present invention can adjust the floating pressure, monitor and feedback the pressure of picking up products, and at the same time avoid the detection blind area where it is impossible to judge whether the suction nozzle on the floating Z-axis touches the product.

Description

Technical Field

[0001] The present invention relates to the field of manipulators, and particularly to a floating Z-axis device with air pressure regulation and its control method. Background Art

[0002] Most of the existing devices for picking up materials (such as small chips, etc.) in the downward direction of the Z-axis adopt a "large Z-axis + R-axis" picking structure. The large Z-axis is fixed on the guide rail, the R-axis is fixed on the large Z-axis, and the large Z-axis drives the structure to pick up products downward through a power source. This method belongs to hard-contact material picking and does not have a floating buffer function device, which easily causes damage to the materials when picking up materials. That is, it is easy to cause overshoot of the moving position and crush the product. For example, when performing chip die bonding, the solder paste expands instantaneously due to temperature change, resulting in an instantaneous upward thrust on the upper structure (such as the suction nozzle) by the product. Because the current picking structure adopts a hard connection, although some structures are equipped with air pressure sensors for real-time monitoring of force control to adjust the output magnitude of the motor force, because the time for chip die bonding is quite fast, the sensor has not had time to transmit the signal to the motor controller, and this instantaneous large pressure has disappeared, but this force has already exerted too much pressure on the product and damaged the product.

[0003] There are also some that adopt a floating small Z-axis solution, but the existing floating small Z-axis solutions cannot achieve the function of pressure regulation, cannot be compatible with the requirements of different products for the picking pressure magnitude; at the same time, there is no monitoring and feedback of pressure, and a pressure closed-loop cannot be achieved. Summary of the Invention

[0004] The technical problem to be solved by the embodiments of the present invention is to provide a floating Z-axis device with air pressure regulation and its control method, so as to accurately control the picking pressure.

[0005] To solve the above technical problem, an embodiment of the present invention provides a floating Z-axis device with air pressure regulation, including an R-axis mechanism, a Z-axis, and further including an air pressure regulation mechanism. An axis cavity corresponding to the Z-axis is provided in the R-axis mechanism, the Z-axis is floatingly arranged in the axis cavity, the air pressure regulation mechanism includes a pressure regulation air path and a switching valve. A pressure regulating valve for regulating the air pressure in the axis cavity and a pressure sensor for detecting the air pressure in the axis cavity are provided in the pressure regulation air path. The axis cavity is communicated with an external positive pressure air source or a negative pressure air source through the pressure regulation air path, and the switching valve is used to switch the connection of the axis cavity to the external positive pressure air source or the negative pressure air source.

[0006] Further, air floating air holes are provided on the inner wall of the axis cavity, and a positive pressure air duct is provided in the R-axis mechanism; one end of the positive pressure air duct is used to connect to an external positive pressure air source, and the other end is communicated with the air floating air holes.

[0007] Further, there are multiple air floating air holes, and the multiple air floating air holes are evenly distributed around the inner wall of the axis cavity.

[0008] Further, the multiple air floating pores are divided into multiple rows vertically, and each row of air floating pores is evenly distributed on the inner wall of the annular shaft cavity.

[0009] Further, the pressure regulating air path is composed of a main air path, a positive pressure air path and a negative pressure air path. One end of the main air path is connected to the shaft cavity, and the other end is connected to one ends of the positive pressure air path and the negative pressure air path. The other ends of the positive pressure air path and the negative pressure air path are respectively used to connect to an external positive pressure air source or a negative pressure air source, and a switching valve is used to control the communication between the main air path and the positive pressure air path or the negative pressure air path.

[0010] Further, there is 1 set of the air pressure sensor and the pressure regulating valve, which are arranged in sequence in the main air path; or there are 2 sets of the air pressure sensor and the pressure regulating valve, which are respectively arranged in the positive pressure air path and the negative pressure air path.

[0011] Further, there are 2 switching valves, which are respectively arranged in the positive pressure air path and the negative pressure air path; or the switching valve adopts a three-way switching valve, and the main air path is connected to the positive pressure air path and the negative pressure air path through the three-way switching valve.

[0012] Further, an air exhaust port for exhausting and decompressing is arranged in the pressure regulating air path, and a pressure relief valve is arranged at the air exhaust port.

[0013] Correspondingly, an embodiment of the present invention further provides a control method for a floating Z-axis device with air path pressure regulation, including the following steps:

[0014] When it is necessary to apply pressure to counterweight the Z-axis, control the switching valve to make the shaft cavity communicate with the external positive pressure air source through the pressure regulating air path, adjust the pressure regulating valve and detect the pressure P in real time through the air pressure sensor, so that the pressure P satisfies the following formula to complete the pressure application and counterweight adjustment:

[0015] P = (F 拾 - F 负 - F 摩 ) / A;

[0016] When it is necessary to reduce pressure to counterweight the Z-axis, control the switching valve to make the shaft cavity communicate with the external negative pressure air source through the pressure regulating air path, adjust the pressure regulating valve and detect the pressure P in real time through the air pressure sensor, so that the pressure P satisfies the following formula to complete the pressure reduction and counterweight adjustment:

[0017] P = (F 负 + F 摩 - F 拾 ) / A;

[0018] Wherein, F 拾 is the required pick-up pressure, F 负 is the sum of the gravity of the Z-axis and the load on the Z-axis, F 摩 is the friction force between the Z-axis and the inner wall of the shaft cavity, and A is the effective pressure-receiving area of the Z-axis.

[0019] Further, during the process of grasping the material, the air pressure sensor continuously detects the pressure change. If the detected pressure changes within a preset range, it is determined that the material has been contacted.

[0020] The beneficial effects of the present invention are as follows: The present invention can adjust the initial pressure of the floating small Z-axis for pressurization or decompression according to product requirements, and at the same time, the pressure value can be monitored through the air pressure sensor. The present invention can adjust the floating pressure, monitor and feedback the pressure magnitude for picking up the product, and at the same time avoid the detection blind area where it is impossible to determine whether the suction nozzle on the floating Z-axis has contacted the product. Brief Description of the Drawings

[0021] Figure 1 is a structural diagram of the floating Z-axis device for air circuit pressure regulation according to an embodiment of the present invention.

[0022] Figure 2 is Figure 1 a cross-sectional view taken along C-C in

[0023] Figure 3 is Figure 2 an enlarged view at F in

[0024] Explanation of the Reference Numerals in the Drawings

[0025] R-axis mechanism 1, Z-axis 2, axis cavity 3, switching valve 4, pressure regulating valve 5, exhaust port 6, pressure relief valve 7, air pressure sensor 8, main air circuit 9, positive pressure air circuit 10, negative pressure air circuit 11, air floating air outlet hole 12, positive pressure air duct 13. Detailed Description of the Embodiment

[0026] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0027] In the embodiments of the present invention, if there are directional indications (such as up, down, left, right, front, back...), they are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0028] In addition, in the present invention, the descriptions such as "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0029] Please refer to Figures 1 to 3 , the floating Z-axis device for air circuit pressure regulation according to the embodiment of the present invention includes an R-axis mechanism, a Z-axis, and an air circuit pressure regulation mechanism.

[0030] The R-axis mechanism consists of a rotating R-axis and a diverter block. An axial cavity corresponding to the Z-axis is provided inside the R-axis mechanism, and the axial cavity is preferably cylindrical. The Z-axis is floatingly arranged in the axial cavity (the axial cavity and the Z-axis are similar in structure to a cylinder block and a piston rod). Specifically, a suction nozzle or a gripper is installed at the lower end of the Z-axis for grasping materials. A gap is left between the Z-axis and the axial cavity, and the gas blown out from the air floating air holes diffuses up and down to form an air film. Preferably, an inner snap ring is provided at the bottom of the R-axis mechanism for limiting the up and down movement of the Z-axis. An exhaust cavity can be provided on the inner wall of the axial cavity, and an exhaust hole communicating with the exhaust cavity is provided on the R-axis mechanism for exhausting gas through the exhaust hole.

[0031] The air circuit pressure regulating mechanism includes a pressure regulating air circuit and a switching valve. A pressure regulating valve for regulating the air pressure in the axial cavity and a pressure sensor for detecting the air pressure in the axial cavity are provided in the pressure regulating air circuit. The axial cavity is communicated with an external positive pressure air source or a negative pressure air source through the pressure regulating air circuit, and the switching valve is used to switch the axial cavity to communicate with the external positive pressure air source or the negative pressure air source. Preferably, the pressure sensor can adopt a pressure gauge, which has not only a display function but also a communication function, that is, the pressure gauge can feedback the pressure value of the pressure regulating air circuit to the controller in real time, so that the controller can adjust and control the motor in real time.

[0032] As an implementation method, an exhaust port for exhausting and decompressing is provided in the pressure regulating air circuit, and a pressure relief valve is provided at the exhaust port. When the pressure sensor suddenly detects a large pressure, it is judged that the Z-axis has a large displacement, and then the pressure relief valve is opened to quickly discharge the air flow through the exhaust port to avoid impact damage to the Z-axis and the product.

[0033] As an implementation method, air floating air holes are provided on the inner wall of the axial cavity, and a positive pressure air duct is provided inside the R-axis mechanism; one end of the positive pressure air duct is used to connect to an external positive pressure air source, and the other end communicates with the air floating air holes. Gas is blown out from the air floating air holes to form an air film between the Z-axis and the inner wall of the axial cavity, thereby reducing the friction when the Z-axis moves up and down.

[0034] As an implementation method, there are multiple air floating air holes, and the multiple air floating air holes are evenly distributed around the inner wall of the axial cavity. Preferably, the multiple air floating air holes are divided into multiple rows up and down, and each row of air floating air holes is evenly distributed around the inner wall of the axial cavity.

[0035] As an implementation method, the pressure regulating air circuit consists of a main air circuit, a positive pressure air circuit and a negative pressure air circuit. One end of the main air circuit communicates with the axial cavity, and the other end is connected to one end of the positive pressure air circuit and the negative pressure air circuit. The other ends of the positive pressure air circuit and the negative pressure air circuit are respectively used to communicate with an external positive pressure air source or a negative pressure air source, and the switching valve is used to control the main air circuit to communicate with the positive pressure air circuit or the negative pressure air circuit.

[0036] As an implementation manner, there is one set of the air pressure sensor, exhaust port, and pressure regulating valve, which are sequentially arranged in the main air path (preferably, the air pressure sensor is arranged on the side close to the shaft cavity); or there are two sets of the air pressure sensor, exhaust port, and pressure regulating valve, which are respectively and sequentially arranged in the positive pressure air path and the negative pressure air path (preferably, the air pressure sensor is arranged on the side close to the main air path).

[0037] As an implementation manner, there are two switching valves, which are respectively arranged in the positive pressure air path and the negative pressure air path; or the switching valve adopts a three-way switching valve, and the main air path is connected to the positive pressure air path and the negative pressure air path through the three-way switching valve.

[0038] The present invention can be directly applied to the end of the existing rotary R-axis picking structure. The rotary R-axis is fixed on the large Z-axis and moves up and down following the large Z-axis. The present invention is fixed at the end of the picking structure and moves following the rotary R-axis. The floating Z-axis of the present invention adopts an air-floating bearing method, so there is no mutual contact between the outer circle of the floating Z-axis and the inner wall of the shaft cavity, but they are separated by an air film. Generally, the air film thickness is between 0.005 and 0.01 mm. In this way, the floating Z-axis is in a floating state. When it is subjected to an upward pressure exceeding the rated value, it will automatically float upward, and will not cause damage to the product below due to the size change of the material and squeezing the product.

[0039] If it is necessary to increase the pressure on the floating Z-axis, then the connection with the negative pressure air source is closed through the switching valve, the connection with the positive pressure air source is opened, and then a positive pressure with a suitable pressure is input through the pressure regulating valve; if it is necessary to reduce the pressure on the floating Z-axis, that is, when it is necessary to reduce the weight of the floating Z-axis and the nozzle device itself pressing on the product, then the connection with the positive pressure air source is closed through the switching valve, the connection with the negative pressure air source is opened, and a negative pressure with a suitable pressure is input through the pressure regulating valve to balance part of the gravity of the floating small Z-axis and the nozzle.

[0040] When the large Z-axis drives the floating Z-axis of the present invention to pick up the product downward, after the floating Z-axis contacts the product, there is an upward displacement fluctuation, resulting in a change in the air pressure inside the shaft cavity. The air pressure sensor on the pressure regulating air path detects the change in pressure, and then transmits the signal to the controller of the large Z-axis to perform the next action, avoiding the situation that due to the different thicknesses of the products, when the large Z-axis moves down to the same height, the nozzle cannot contact the thin product or the product at a lower position, resulting in an abnormal vacuum for sucking the product.

[0041] The control method of the floating Z-axis device for air path pressure regulation according to the embodiment of the present invention includes the following steps:

[0042] When it is necessary to perform pressure weighting on the Z-axis, control the switching valve to connect the shaft cavity to the external positive pressure air source through the pressure regulating air path, adjust the pressure regulating valve, and detect the pressure P in real time through the air pressure sensor, so that the pressure P satisfies the following formula to complete the pressure weighting adjustment:

[0043] P = (F 拾 - F 负 - F 摩 ) / A;

[0044] When it is necessary to perform decompression counterweight on the Z-axis, control the on-off valve to connect the shaft cavity to the external negative pressure air source through the pressure regulating air circuit, adjust the pressure regulating valve and detect the pressure P in real time through the air pressure sensor, so that the pressure P satisfies the following formula to complete the decompression counterweight adjustment:

[0045] P = (F 负 + F 摩 - F 拾 ) / A;

[0046] Wherein, F 拾 is the required picking pressure (i.e., the picking pressure applied in the vertical direction to the picked material product), F 负 is the sum of the gravity of the Z-axis and the load on the Z-axis, and F 摩 is the frictional force between the Z-axis and the inner wall of the shaft cavity. A is the effective pressure-bearing area of the Z-axis (i.e., the area of the upper end face of the Z-axis). That is A = π × ([[]] d / 2)[[]] 2 , where d is the diameter of the part of the Z-axis inside the shaft cavity.

[0047] As an implementation manner, during the process of grasping the material, the air pressure sensor continuously detects the pressure change. If the detected pressure changes within a preset range, it is determined that the material has been contacted, and then the next action is performed.

[0048] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalent scope.

Claims

1. A floating Z-axis device for air pressure regulation of an air path, comprising an R-axis mechanism and a Z-axis, characterized in that, It further includes a gas path pressure regulating mechanism. An axial cavity corresponding to the Z-axis is provided inside the R-axis mechanism. The Z-axis is floatingly arranged in the axial cavity. The gas path pressure regulating mechanism includes a pressure regulating gas path and a switching valve. A pressure regulating valve for adjusting the air pressure in the axial cavity and a pressure sensor for detecting the air pressure in the axial cavity are provided in the pressure regulating gas path. The axial cavity is connected to an external positive pressure gas source and a negative pressure gas source through the pressure regulating gas path. The switching valve is used to switch the connection of the axial cavity to the external positive pressure gas source or the negative pressure gas source; Air floating air holes are provided on the inner wall of the axial cavity, and a positive pressure air duct is provided inside the R-axis mechanism; one end of the positive pressure air duct is used to connect to an external positive pressure gas source, and the other end is communicated with the air floating air holes.

2. The floating Z-axis device for air pressure regulation according to claim 1, wherein There are multiple air floating air holes, and the multiple air floating air holes are evenly distributed around the inner wall of the axial cavity.

3. The floating Z-axis device for air pressure regulation according to claim 2, wherein, The multiple air floating air holes are divided into multiple rows up and down, and each row of air floating air holes is evenly distributed around the inner wall of the axial cavity.

4. The floating Z-axis device for air pressure regulation according to claim 1, wherein The pressure regulating gas path is composed of a main gas path, a positive pressure gas path and a negative pressure gas path. One end of the main gas path is communicated with the axial cavity, and the other end is connected to one ends of the positive pressure gas path and the negative pressure gas path. The other ends of the positive pressure gas path and the negative pressure gas path are respectively used to communicate with an external positive pressure gas source and a negative pressure gas source. The switching valve is used to control the communication between the main gas path and the positive pressure gas path or the negative pressure gas path.

5. The floating Z-axis device for air pressure regulation according to claim 4, wherein There is 1 group of the pressure sensor and the pressure regulating valve, which are sequentially arranged in the main gas path; or there are 2 groups of the pressure sensor and the pressure regulating valve, which are respectively arranged in the positive pressure gas path and the negative pressure gas path.

6. The floating Z-axis device for air pressure regulation according to claim 4, characterized in that, There are 2 switching valves, which are respectively arranged in the positive pressure gas path and the negative pressure gas path; or the switching valve adopts a three-way switching valve, and the main gas path is connected to the positive pressure gas path and the negative pressure gas path through the three-way switching valve.

7. The floating Z-axis device for air pressure regulation according to claim 1, wherein An exhaust port for exhausting and decompressing is provided in the pressure regulating gas path, and a pressure relief valve is provided at the exhaust port.

8. A control method for a floating Z-axis device with air pressure regulation in the air path as described in any one of claims 1 to 7, characterized in that, It includes the following steps: When it is necessary to apply pressure and counterweight to the Z-axis, control the switching valve to make the axial cavity communicate with the external positive pressure gas source through the pressure regulating gas path, adjust the pressure regulating valve and detect the pressure P in real time through the pressure sensor, so that the pressure P satisfies the following formula to complete the adjustment of pressure and counterweight: P = (F 拾 - F 负 - F 摩 ) / A; When it is necessary to reduce pressure and counterweight to the Z-axis, control the switching valve to make the axial cavity communicate with the external negative pressure gas source through the pressure regulating gas path, adjust the pressure regulating valve and detect the pressure P in real time through the pressure sensor, so that the pressure P satisfies the following formula to complete the adjustment of pressure and counterweight: P = (F 负 + F 摩 - F 拾 ) / A; Among them, F 拾 is the required pick-up pressure, F 负 is the sum of the gravity of the Z-axis and the load on the Z-axis, and F 摩 is the frictional force between the Z-axis and the inner wall of the shaft cavity, and A is the effective pressure-bearing area of the Z-axis.

9. The control method of the floating Z-axis device for air pressure regulation according to claim 8, characterized in that, During the process of grasping materials, the pressure sensor continuously detects the pressure change. If the detected pressure changes within a preset range, it is determined that the material has been contacted.

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