Floating Z-axis device for air path pressure regulation and control method of floating Z-axis device

Abstract

The floating Z-axis device comprises an R-axis mechanism, a Z-axis and an air path pressure regulating mechanism, a shaft cavity corresponding to the Z-axis is formed in the R-axis mechanism, the Z-axis is arranged in the shaft cavity in a floating mode, and the air path pressure regulating mechanism comprises a pressure regulating air path and a switch valve. A pressure regulating valve used for regulating air pressure in the shaft cavity and an air pressure sensor used for detecting the air pressure in the shaft cavity are arranged in the pressure regulating air channel, the shaft cavity communicates with an external positive pressure air source or an external negative pressure air source through the pressure regulating air channel, and the switching valve is used for switching the shaft cavity to communicate with the external positive pressure air source or the external negative pressure air source. According to the invention, the floating pressure can be adjusted, and the pressure of a picked product can be monitored and fed back, and meanwhile, a detection blind area which cannot judge whether the suction nozzle on the floating Z axis is in contact with the product or not is avoided.

Description

Technical Field

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

[0002] Most of the existing Z-axis downward picking-up materials (such as small chips, etc.) devices use a "large Z-axis + R-axis" picking-up structure. The large Z-axis is fixed on the guide rail, and the R-axis is fixed on the large Z-axis. The large Z-axis drives the structure downward to pick up the product through a power source. This method belongs to hard contact picking up materials, and there is no floating buffer function device, which is easy to cause damage to the material when picking up the material. That is, it is easy to cause the movement position to overshoot and crush the product. For example, when the chip is solidified, the solder paste temperature changes and expands instantly, causing the product to have an instantaneous upward thrust on the upper structure (such as the suction nozzle). Because the current picking structure adopts hard connection, although some structures are equipped with air pressure sensors for real-time monitoring of force control to adjust the output size of the motor force, because the chip solidification time 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 excessive pressure on the product and damaged the product.

[0003] Some also adopt a floating small Z-axis solution, but the existing floating small Z-axis solution cannot realize the pressure adjustment function and cannot be compatible with the requirements of different products for the picking pressure size; at the same time, there is no pressure monitoring and feedback, and the 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 circuit pressure regulation and a control method thereof, so as to enable accurate control of the pickup pressure.

[0005] In order to solve the above technical problems, an embodiment of the present invention proposes a floating Z-axis device with air circuit pressure regulation, including an R-axis mechanism, a Z-axis, and an air circuit pressure regulating mechanism. The R-axis mechanism is provided with an axial cavity corresponding to the Z-axis, and the Z-axis is floatingly arranged in the axial cavity. The air circuit pressure regulating mechanism includes a pressure regulating air circuit and a switch valve. The pressure regulating air circuit is provided with a pressure regulating valve for adjusting the air pressure in the axial cavity and an air pressure sensor for detecting the air pressure in the axial cavity. The axial cavity is connected to an external positive pressure air source or a negative pressure air source through the pressure regulating air circuit, and the switch valve is used to switch the axial cavity to connect to the external positive pressure air source or the negative pressure air source.

[0006] Furthermore, an air flotation outlet hole is provided on the inner wall of the shaft cavity, and a positive pressure airway is provided in the R-axis mechanism; one end of the positive pressure airway is used to connect to an external positive pressure air source, and the other end is connected to the air flotation outlet hole.

[0007] Furthermore, there are a plurality of air flotation outlet holes, and the plurality of air flotation outlet holes are evenly distributed around the inner wall of the shaft cavity.

[0008] Furthermore, the plurality of air flotation outlet holes are divided into a plurality of rows up and down, and the air flotation outlet holes are evenly distributed around the inner wall of the axial cavity.

[0009] Furthermore, the pressure regulating air circuit is composed of a main air circuit, a positive pressure air circuit and a negative pressure air circuit. One end of the main air circuit is connected to 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 connect to an external positive pressure air source or a negative pressure air source, and the switch valve is used to control the main air circuit to be connected to the positive pressure air circuit or the negative pressure air circuit.

[0010] Furthermore, there is one group of the air pressure sensor and the pressure regulating valve, which are sequentially arranged in the main air circuit; or there are two groups of the air pressure sensor and the pressure regulating valve, which are respectively arranged in the positive pressure air circuit and the negative pressure air circuit.

[0011] Furthermore, there are two switch valves, which are respectively arranged in the positive pressure gas circuit and the negative pressure gas circuit; or the switch valve adopts a 3-way switch valve, and the main gas circuit is connected to the positive pressure gas circuit and the negative pressure gas circuit through the 3-way switch valve.

[0012] Furthermore, an exhaust port for exhausting and reducing pressure is provided in the pressure regulating gas circuit, and a pressure relief valve is provided at the exhaust port.

[0013] Accordingly, an embodiment of the present invention further provides a method for controlling a floating Z-axis device with air path pressure regulation, comprising the following steps: When the Z-axis needs to be pressurized and counterweighted, the switch valve is controlled to connect the axis cavity to the external positive pressure gas source through the pressure regulating gas path, and the pressure regulating valve is adjusted and the pressure P is detected in real time through the air pressure sensor so that the pressure P satisfies the following formula to complete the pressurized counterweight adjustment: P = (F 拾 -F 负 -F 摩 ) / A; When the Z-axis needs to be decompressed and counterweighted, the switch valve is controlled to connect the axis cavity to the external negative pressure gas source through the pressure regulating gas path, and the pressure regulating valve is adjusted and the pressure P is detected in real time through the air pressure sensor so that the pressure P satisfies the following formula to complete the decompression and counterweight adjustment: P = (F 负 +F 摩 -F 拾 ) / A; Among them, F 拾 is the required pick-up pressure, F 负 is the gravity and 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 area of ​​the Z-axis.

[0014] Furthermore, the air pressure sensor continuously detects pressure changes during the process of grabbing the material. If the detected pressure changes within a preset range, it is determined that the material is contacted.

[0015] The beneficial effects of the present invention are as follows: the present invention can adjust the initial pressure of the floating small Z axis to increase or reduce pressure according to product requirements, and at the same time monitor the pressure value through the air pressure sensor. The present invention can adjust the floating pressure and monitor and feedback the pressure of the product being picked up, while avoiding the detection blind area where it is impossible to judge whether the suction nozzle on the floating Z axis has touched the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of a floating Z-axis device with air path pressure regulation according to an embodiment of the present invention.

[0017] Figure 2 yes Figure 1 Cross-sectional view at CC.

[0018] Figure 3 yes Figure 2 Enlarged view of point F in the middle.

[0019] Description of Figure Numbers R-axis mechanism 1, Z-axis 2, axis cavity 3, switch valve 4, pressure regulating valve 5, exhaust port 6, pressure relief valve 7, air pressure sensor 8, main air path 9, positive pressure air path 10, negative pressure air path 11, air flotation outlet hole 12, positive pressure air channel 13. DETAILED DESCRIPTION

[0020] It should be noted that, in the absence of conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0021] In the embodiments of the present invention, if there are directional indications (such as up, down, left, right, front, back, etc.), they are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, in the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0023] Please refer to Figure 1 to Figure 3 The floating Z-axis device with 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.

[0024] The R-axis mechanism consists of a rotating R-axis and a diverter seat. An axial cavity corresponding to the Z-axis is provided in 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 structure are similar to the cylinder body and the piston rod). During the specific implementation, a suction nozzle or a clamp is installed at the lower end of the Z-axis for grabbing materials. A gap is left between the Z-axis and the axial cavity, and the gas blown out of the air flotation hole diffuses up and down to form an air film. Preferably, an inner retaining ring is provided at the bottom of the R-axis mechanism, and the inner retaining ring is used to limit the up and down movement of the Z-axis. An exhaust cavity may be provided on the inner wall of the axial cavity, and an exhaust hole connected to the exhaust cavity is provided on the R-axis mechanism, and exhaust is exhausted through the exhaust hole.

[0025] The air circuit pressure regulating mechanism includes a pressure regulating air circuit and a switch valve. The pressure regulating air circuit is provided with a pressure regulating valve for regulating the air pressure in the shaft cavity and an air pressure sensor for detecting the air pressure in the shaft cavity. The shaft cavity is connected to an external positive pressure air source or a negative pressure air source through the pressure regulating air circuit. The switch valve is used to switch the shaft cavity to connect to an external positive pressure air source or a negative pressure air source. Preferably, the air pressure sensor can be a pressure gauge. In addition to the display function, the pressure gauge also has a communication function, that is, the pressure gauge can feed back 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.

[0026] As an implementation method, an exhaust port for exhausting and reducing pressure is provided in the pressure regulating gas circuit, and a pressure relief valve is provided at the exhaust port. When the air pressure sensor suddenly detects a large pressure, it is judged that a large displacement of the Z axis occurs, and the pressure relief valve is opened to quickly discharge the airflow through the exhaust port to avoid impact damage to the Z axis and the product.

[0027] As an implementation method, an air flotation outlet hole is provided on the inner wall of the shaft cavity, and a positive pressure airway is provided in the R-axis mechanism; one end of the positive pressure airway is used to connect to an external positive pressure air source, and the other end is connected to the air flotation outlet hole. Gas is blown out of the air flotation outlet hole to form an air film between the Z axis and the inner wall of the shaft cavity, thereby reducing the friction when the Z axis moves up and down.

[0028] As an embodiment, there are multiple air flotation outlet holes, and the multiple air flotation outlet holes are evenly distributed around the inner wall of the shaft cavity. Preferably, the multiple air flotation outlet holes are divided into multiple rows up and down, and the exhaust flotation outlet holes are evenly distributed around the inner wall of the shaft cavity.

[0029] As an implementation mode, the pressure regulating air circuit is composed of a main air circuit, a positive pressure air circuit and a negative pressure air circuit. One end of the main air circuit is connected to 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 connect to an external positive pressure air source or a negative pressure air source, and the switch valve is used to control the connection between the main air circuit and the positive pressure air circuit or the negative pressure air circuit.

[0030] As an implementation mode, there is one group of the air pressure sensor, the exhaust port, and the pressure regulating valve, which are sequentially arranged in the main air circuit (preferably, the air pressure sensor is arranged on the side close to the axial cavity); or there are two groups of the air pressure sensor, the exhaust port, and the pressure regulating valve, which are respectively sequentially arranged in the positive pressure air circuit and the negative pressure air circuit (preferably, the air pressure sensor is arranged on the side close to the main air circuit).

[0031] As an implementation mode, there are two switch valves, which are respectively arranged in the positive pressure air circuit and the negative pressure air circuit; or the switch valve adopts a 3-way switch valve, and the main air circuit connects the positive pressure air circuit and the negative pressure air circuit through the 3-way switch valve.

[0032] The present invention can be directly applied to the end of the existing rotating R-axis picking structure. The rotating R-axis is fixed on the large Z-axis and moves up and down with the large Z-axis. The present invention is fixed at the end of the picking structure and moves with the rotating R-axis. The floating Z-axis of the present invention adopts an air bearing, so the outer circle of the floating Z-axis and the inner wall of the shaft cavity are not in contact with each other, but are separated by an air film. The thickness of the air film is generally 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 the material below to extrude the product due to size changes and damage the product.

[0033] If it is necessary to increase the pressure on the floating Z-axis, the connection with the negative pressure air source is closed through the switch valve, the connection with the positive pressure air source is opened, and then the positive pressure of the appropriate pressure is input through the pressure regulating valve; if it is necessary to reduce the pressure on the floating Z-axis, that is, to reduce the weight of the floating Z-axis and the suction nozzle device itself on the product, the connection with the positive pressure air source is closed through the switch valve, the connection with the negative pressure air source is opened, and the negative pressure of the appropriate pressure is input through the pressure regulating valve to balance the gravity of part of the floating small Z-axis and the suction nozzle.

[0034] When the large Z-axis drives the floating Z-axis of the present invention to pick up products downward, the floating Z-axis has an upward displacement fluctuation after contacting the product, resulting in a change in the air pressure inside the axis cavity. The air pressure sensor on the pressure regulating air circuit detects the pressure change and transmits the signal to the controller of the large Z-axis to execute the next step, thereby avoiding the situation where the suction nozzle cannot touch the thin product or the low-position product when the large Z-axis moves down to the same height due to the different thickness of the products, resulting in abnormal vacuum alarm when sucking the product.

[0035] The control method of the floating Z-axis device with air path pressure regulation according to the embodiment of the present invention comprises the following steps: When the Z-axis needs to be pressurized and counterweighted, the switch valve is controlled to connect the axis cavity to the external positive pressure gas source through the pressure regulating gas path, and the pressure regulating valve is adjusted and the pressure P is detected in real time through the air pressure sensor so that the pressure P satisfies the following formula to complete the pressurized counterweight adjustment: P = (F 拾-F 负 -F 摩 ) / A; When the Z-axis needs to be decompressed and counterweighted, the switch valve is controlled to connect the axis cavity to the external negative pressure gas source through the pressure regulating gas path, and the pressure regulating valve is adjusted and the pressure P is detected in real time through the air pressure sensor so that the pressure P satisfies the following formula to complete the decompression and counterweight adjustment: P = (F 负 +F 摩 -F 拾 ) / A; Among them, F 拾 is the required picking pressure (i.e. the picking pressure applied to the picked material in the vertical direction), F 负 is the gravity and load on the Z axis, F 摩 is the friction force between the Z axis and the inner wall of the shaft cavity. A is the effective pressure area of ​​the Z axis (i.e. the end surface area of ​​the upper end of the Z axis). A = π ×( d / 2) 2 ,in d is the diameter of the Z-axis portion in the shaft cavity.

[0036] As an implementation method, the air pressure sensor continuously detects pressure changes during the process of grabbing materials. If the detected pressure changes within a preset range, it is determined that the material is contacted and the next action is performed.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A floating Z-axis device with air pressure regulation, comprising an R-axis mechanism and a Z-axis, characterized in that: It also includes an air circuit pressure regulating mechanism, in which an axial cavity corresponding to the Z axis is provided in the R-axis mechanism, and the Z axis is floatingly arranged in the axial cavity. The air circuit pressure regulating mechanism includes a pressure regulating air circuit and a switch valve. The pressure regulating air circuit is provided with a pressure regulating valve for regulating the air pressure in the axial cavity and an air pressure sensor for detecting the air pressure in the axial cavity. The axial cavity is connected to an external positive-pressure air source or a negative-pressure air source through the pressure regulating air circuit, and the switch valve is used to switch the axial cavity to connect to an external positive-pressure air source or a negative-pressure air source.

2. The floating Z-axis device with air path pressure regulation according to claim 1, characterized in that: An air flotation outlet hole is arranged on the inner wall of the shaft cavity, and a positive pressure airway is arranged in the R-axis mechanism; one end of the positive pressure airway is used to connect to an external positive pressure air source, and the other end is connected to the air flotation outlet hole.

3. The floating Z-axis device with air path pressure regulation according to claim 2, characterized in that: There are a plurality of air flotation outlet holes, and the plurality of air flotation outlet holes are evenly distributed around the inner wall of the shaft cavity.

4. The floating Z-axis device with air path pressure regulation according to claim 3, characterized in that: The plurality of air flotation outlet holes are divided into a plurality of rows up and down, and the air flotation outlet holes are evenly distributed around the inner wall of the axial cavity.

5. The floating Z-axis device with air path pressure regulation according to claim 1, characterized in that: The pressure regulating air circuit is composed of a main air circuit, a positive pressure air circuit and a negative pressure air circuit. One end of the main air circuit is connected to the shaft 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 connect to an external positive pressure air source or a negative pressure air source. The switch valve is used to control the main air circuit to be connected to the positive pressure air circuit or the negative pressure air circuit.

6. The floating Z-axis device with air path pressure regulation according to claim 5, characterized in that: There is one set of the air pressure sensor and the pressure regulating valve, which are sequentially arranged in the main air circuit; or there are two sets of the air pressure sensor and the pressure regulating valve, which are respectively arranged in the positive pressure air circuit and the negative pressure air circuit.

7. The floating Z-axis device with air path pressure regulation according to claim 5, characterized in that: There are two switch valves, which are respectively arranged in the positive pressure gas circuit and the negative pressure gas circuit; or the switch valve adopts a 3-way switch valve, and the main gas circuit is connected to the positive pressure gas circuit and the negative pressure gas circuit through the 3-way switch valve.

8. The floating Z-axis device with air path pressure regulation according to claim 1, characterized in that: An exhaust port for exhausting and reducing pressure is provided in the pressure regulating gas circuit, and a pressure relief valve is provided at the exhaust port.

9. A control method for a floating Z-axis device with air path pressure regulation according to any one of claims 1 to 8, characterized in that: The following steps are involved: When the Z-axis needs to be pressurized and counterweighted, the switch valve is controlled to connect the axis cavity to the external positive pressure gas source through the pressure regulating gas path, and the pressure regulating valve is adjusted and the pressure P is detected in real time through the air pressure sensor so that the pressure P satisfies the following formula to complete the pressurized counterweight adjustment: P=(F 拾 -F 负 -F 摩 ) / A; When the Z-axis needs to be decompressed and counterweighted, the switch valve is controlled to connect the axis cavity to the external negative pressure gas source through the pressure regulating gas path, and the pressure regulating valve is adjusted and the pressure P is detected in real time through the air pressure sensor so that the pressure P satisfies the following formula to complete the decompression and counterweight adjustment: P=(F 负 +F 摩 - F 拾 ) / A; Among them, F 拾 is the required pick-up pressure, F 负 is the gravity and 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 area of ​​the Z-axis.

10. The control method of the floating Z-axis device with air path pressure regulation according to claim 9, characterized in that: The air pressure sensor continuously detects pressure changes during the process of grabbing materials. If the detected pressure changes within a preset range, it is determined that the material is in contact.

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