Zero returning device and numerical control equipment

Abstract

The invention relates to a zero returning device and numerical control equipment, the numerical control equipment is provided with the zero returning device, and the zero returning device comprises a zero returning combination switch, a speed reduction collision block and a limit collision block; the speed reduction collision block and the limit collision block are matched with the speed reduction switch and the top speed switch of the zero returning combination switch in position, the speed reduction collision block and the limit collision block are arranged in parallel in the running direction of the zero returning part and partially overlapped in the vertical direction, and the speed reduction collision block facing the zero returning direction is located at the front end of the limit collision block. When the machine tool returns to zero, the position of the sliding table does not need to be considered, zero returning can be operated as long as a limit alarm does not occur, the machine tool retreats to find a zero point and stops after automatically recognizing the speed reduction collision block, and meanwhile a zero point signal is set. And if the speed reduction switch is damaged, zero returning fails, and a machine tool presses an upper limit switch, the machine tool can normally give an alarm.

Description

Technical Field

[0001] The invention belongs to the technical field of numerical control equipment, and relates to a zero return device for numerical control equipment, and in particular to the position setting of a switch for a zero return point and a collision block. Background Art

[0002] The mechanical zero point of a CNC device is a fixed point on the machine tool, which is determined by the zero point signal (usually called the one-turn signal) in the encoder of the servo motor installed on the machine tool. Under normal circumstances, machine tools with a relative zero point structure need to be returned to the zero point before work. The general method is to install a deceleration switch near the maximum stroke in the X or Z direction. After the machine tool presses the deceleration switch, it decelerates to a specified low speed and waits for the one-turn signal to appear. After receiving the one-turn signal, it stops moving and memorizes the coordinates of the point as the zero point. This is usually called the machine tool returning to the reference point. Currently in the field of mechanical processing, all relative zero point structure equipment must be equipped with a mechanical bump block, which is installed on the slide of the machine tool. The length of the bump block must be greater than or equal to 2.5 times the lead of the transmission screw used.

[0003] For machine tools with relative zero point setting, there are generally two ways to return to zero: one is to press the deceleration switch first when returning to zero, the slide decelerates to the zero return low speed, and after passing the deceleration bump at low speed, the movement stops after the zero point pulse is detected, the zero point is calibrated, and the mechanical return to zero operation is completed; the other is that after passing the deceleration bump, the slide returns at the zero return low speed, and after leaving the deceleration bump, it stops after the zero point pulse is detected, the zero point is calibrated, and the mechanical return to zero operation is completed.

[0004] The above two relative zero return schemes have their pros and cons: when the machine tool is using the maximum stroke, the deceleration block will press the deceleration switch. If the number of times per day is too many, the switch will be used for a short period of time and its life will end prematurely. If the deceleration switch is not pressed intentionally, the effective length of the machine tool guide rail will be shortened. If the limit switch is not pressed for a long time, it is easy to rust and other faults, and the failure of the function will not be displayed. Furthermore, if the machine tool (bump) happens to stop between the deceleration switch and the limit switch, zero return at this time will cause the machine tool to have an over-travel fault. Summary of the invention

[0005] In order to solve the problems existing in the above-mentioned prior art, the present invention proposes a zero return device and a CNC equipment having the zero return device, which can return to zero as long as the slide does not have an extreme alarm, and the zero point position greatly reduces the occupancy of the guide rail, and each time the slide returns to zero, a deceleration and an extreme limit switch are pressed.

[0006] The present invention is achieved through the following technical solutions: The above-mentioned return to zero device includes a return to zero combination switch, a deceleration bump block and a limit bump block; the return to zero combination switch includes a stacked deceleration switch and a maximum speed switch, and the deceleration switch and the maximum speed switch are stacked up and down along the running direction of the return component; the deceleration bump block and the limit bump block match the positions of the deceleration switch and the maximum speed switch, and are arranged in parallel along the running direction of the return component and partially overlap in the vertical direction, and the deceleration bump block is located at the front end of the limit bump block facing the return to zero direction.

[0007] The return-to-zero device, wherein: the size of the overlapping portion between the deceleration block and the limit block is 4-6 mm.

[0008] The return to zero device, wherein: the deceleration collision block is an isosceles trapezoidal structure with two symmetrical inclined surfaces, and the two inclined surfaces at the front and rear ends of the deceleration collision block match the contact fingers contacting the deceleration switch, and pressing the deceleration switch during movement triggers the deceleration signal.

[0009] The return-to-zero device, wherein: the limit collision block is an isosceles trapezoidal structure with two symmetrical inclined surfaces, the two inclined surfaces at the front and rear ends of the limit collision block match the contact fingers of the limit switch and are at the same height as the deceleration collision block.

[0010] The above-mentioned numerical control equipment includes a bed and a slide, and the bed operating platform is provided with a slide rail; the slide rail is slidably assembled on the slide rail; and the equipment has the above-mentioned zero return device.

[0011] The described numerical control equipment, wherein: the return to zero combination switch is installed on the guide rail of the bed through a bracket; the deceleration switch and the limit combination switch are stacked up and down on the bracket, and the switch contacts extend toward the direction of the slide; the deceleration block is installed on the side of the slide, matching the height of the deceleration switch; the limit block is installed on the side of the slide, located obliquely below the deceleration block, partially overlapping with the deceleration block in the vertical direction, matching the height of the extreme speed switch.

[0012] The numerical control equipment, wherein: the control system includes a PLC, and the PLC determines and identifies the zero point according to the working mode when the deceleration switch and the extreme speed switch are pressed simultaneously in the zero return mode. Beneficial Effects

[0013] The zero return device of the present invention partially overlaps the deceleration block and the limit block, and presses the limit switch at the end of the deceleration movement of the deceleration switch, thereby shortening the zero return stroke of the return component, and there is no need to consider the specific position of the return component. As long as the limit switches at both ends are not pressed in the limit alarm state, it can return to zero and find the zero point in a pre-set manner, and the zero point position greatly reduces the occupancy of the guide rail; similarly, when the deceleration switch fails and cannot send a normal signal, the machine tool can also identify and alarm. In particular, this solution does not increase accessories, has a simple structure, low cost, easy installation and maintenance, stable and reliable use, and can be widely used in automation equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural principle diagram of the zero return device of the present invention; Figure 2 A schematic diagram of the zero return process of the zero return device of the present invention; Figure 3 It is a structural schematic diagram of a numerical control device with a zero return device according to an embodiment of the present invention; Figure 4 for Figure 3 A partial enlarged view of . DETAILED DESCRIPTION

[0015] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0016] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication, it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. Some embodiments of the present application will be described in detail below in conjunction with the accompanying drawings.

[0017] The embodiments of the present application are further described below in conjunction with the accompanying drawings.

[0018] like Figure 1 As shown, the zero return device 3 of the present invention comprises a zero return combination switch 31, a deceleration bump block 32 and a limit bump block 33; The return-to-zero combination switch 31 includes a stacked deceleration switch 312 and a maximum speed switch 313, and the deceleration switch 312 and the maximum speed switch 313 are stacked up and down along the running direction of the return component; The deceleration block 32 and the limit block 33 match the positions of the deceleration switch 312 and the extreme speed switch 313, and are arranged in parallel along the running direction of the return parts and partially overlap in the vertical direction, that is, after the deceleration switch presses on the deceleration block 32 and has not yet left, the limit switch 313 presses on the extreme speed block 33; the size S of the overlapping part is preferably selected to be 4-6mm.

[0019] The zero return process of the zero return device is described by taking the zero point setting of the servo motor as an example. Figure 2 As shown: the first step is that the slide is running, the deceleration switch of the combination switch presses the deceleration bump, triggering the deceleration signal and decelerating the operation; the second step is that the extreme speed switch of the combination switch presses the extreme speed bump, triggering the limit signal and stopping the operation; the third step is that after pausing, press the return to zero speed to reverse, the combination switch turns the extreme speed switch to leave the limit bump, and continues to reverse the deceleration switch to leave the deceleration bump; the fourth step is that the zero point signal appears and the slide stops, and the return to zero is completed.

[0020] The zero return device has the deceleration bump 32 and the limit bump 33 arranged overlappingly in the vertical part of the running direction of the return component, and presses the limit switch at the same time at the end of the deceleration movement of the deceleration switch, thereby shortening the zero return stroke of the return component, and there is no need to consider the specific position of the return component. As long as the limit switches at both ends are not pressed and are in the limit alarm state, zero return can be performed and the zero point can be found in a pre-set manner. Similarly, when the deceleration switch fails and cannot send a normal signal, the machine tool can also recognize and alarm.

[0021] When the size of the overlapping part is 4-6mm, the slide can return to zero in time with a short stroke, and the zero point position greatly reduces the occupancy of the guide rail, which can reduce the length of the slide rail and reduce costs.

[0022] The numerical control equipment of the present invention is equipped with the zero return device of the present invention, and the following is explained by taking a horizontal numerical control lathe as an example. Figure 3 , Figure 4 As shown, the device includes a bed 1, a slide 2, a zero return device 3, and a control system (not shown).

[0023] A slide rail 11 is arranged on the operating platform of the bed 1 .

[0024] The slide table 2 is slidably mounted on the slide rail 11 of the bed 1 and driven by the servo motor 21 to reciprocate along the slide rail 21 on the operating platform.

[0025] The zero return device 3 is used for the zero return of the slide 2, and includes a zero return combination switch 31, a limit bumper 32 and a deceleration bumper 33; the zero return combination switch 31 is installed on the bed 1 through a bracket 311, and is assembled with a deceleration switch 312 and a limit switch 313; the bracket 311 is fixedly assembled on the guide rail 11 of the bed 1; the deceleration switch 312 and the limit combination switch are stacked on the bracket 311, and the switch contacts extend toward the slide 2.

[0026] The deceleration block 32 is installed on the side of the slide 2 and matches the height of the deceleration switch 312; the deceleration block 32 is an isosceles trapezoidal structure with two symmetrical inclined surfaces. The two inclined surfaces at the front and rear ends of the deceleration block 32 match the contact fingers that contact the deceleration switch 32. When moving, pressing the deceleration switch triggers the deceleration signal.

[0027] The limit block 33 is installed on the side of the slide 2, located obliquely below the deceleration block 32, partially overlapping with the deceleration block 32 in the vertical direction, and matching the height of the extreme speed switch 313; the limit block 33 is an isosceles trapezoidal structure with two symmetrical inclined surfaces. The two inclined surfaces at the front and rear ends of the limit block 33 match the contact fingers that contact the limit switch 31, and are at the same height as the deceleration block 32. When moving, the limit switch is pressed to trigger the limit signal. The size of the overlapped part of the limit block 33 and the deceleration block 32 in the vertical direction is preferably 4-6mm.

[0028] The front end of the deceleration block 32 facing the zero return direction is the deceleration switch 312, and the rear end is the limit block 33, and the position overlaps with the front end of the limit block 33 by about 5 mm. The purpose of the overlap is to allow the machine tool to return to zero and press the deceleration switch at the end of the deceleration movement while pressing the limit switch, and then send out the deceleration signal and then the limit signal.

[0029] The control system includes a PLC, and the identification of the zero point depends on the PLC's judgment based on the working mode. The identification of the zero point depends on the PLC's judgment based on the working mode. Only in the zero return mode, when both switches are pressed at the same time, it does not mean that the slide limit has been exceeded.

[0030] By overlapping the deceleration bump block 32 and the limit bump block 33 by no less than 5CM, the deceleration switch 312 and the extreme speed switch 313 are pressed at the same time when returning to zero. After PLC recognition, the overtravel limit alarm is shielded and the slide 2 exit signal is issued at the same time. The slide 2 returns at a low speed to return to zero. After leaving the deceleration bump block 32, it detects the one-turn signal issued by the encoder to stop and set the zero point.

[0031] The CNC machine tool slide zero return device of the present invention does not need to consider the specific position of the slide when returning to zero. As long as the limit switches at both ends are not pressed and it is in the limit alarm state, it can return to zero and find the zero point in a pre-set manner; when the deceleration switch fails and cannot send a normal signal, the machine tool cannot find the zero point when returning to zero, it can also send out a limit alarm, and identify the deceleration switch failure through program judgment and alarm. In particular, this solution does not add accessories, has a simple structure, low cost, easy installation and maintenance, stable and reliable use, and can be widely used in automation equipment.

[0032] It is obvious to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present application.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application and are not intended to limit it. Although the present application has been described in detail with reference to the preferred embodiments, a person of ordinary skill in the art should understand that the technical solution of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present application.

Claims

1. A zero return device, characterized in that: The zero return device includes a zero return combination switch, a deceleration bumper and a limit bumper; The return-to-zero combination switch includes a stacked deceleration switch and a maximum speed switch, and the deceleration switch and the maximum speed switch are stacked up and down along the running direction of the return component; The deceleration bumper and the limit bumper match the positions of the deceleration switch and the extreme speed switch, are arranged in parallel along the running direction of the return component, and partially overlap in the vertical direction, and the deceleration bumper is located at the front end of the limit bumper facing the zero return direction.

2. The zero return device according to claim 1, characterized in that: The size of the overlapping portion between the deceleration block and the limit block is 4-6 mm.

3. The zero return device according to claim 1, characterized in that: The deceleration block is an isosceles trapezoidal structure with two symmetrical inclined surfaces. The two inclined surfaces at the front and rear ends of the deceleration block match the contact fingers contacting the deceleration switch. When moving, pressing the deceleration switch triggers a deceleration signal.

4. The return-to-zero device according to claim 1, characterized in that: The limit collision block is an isosceles trapezoidal structure with two symmetrical inclined surfaces. The two inclined surfaces at the front and rear ends of the limit collision block match the contact fingers of the limit switch and have the same height as the deceleration collision block.

5. A numerical control device, comprising a bed and a slide, wherein the bed operating platform is provided with a slide rail; the slide rail is slidably mounted on the slide rail; characterized in that: The device has a return-to-zero device as described in any one of claims 1-4.

6. The numerical control device according to claim 5, characterized in that: The return-to-zero combination switch is installed on the guide rail of the bed through a bracket; the deceleration switch and the limit combination switch are stacked on the bracket, and the switch contacts extend toward the direction of the slide; The deceleration block is installed on the side of the slide and matches the height of the deceleration switch; The limit collision block is installed on the side of the slide, located obliquely below the deceleration collision block, partially overlapping with the deceleration collision block in the vertical direction, and matching the height of the extreme speed switch.

7. The numerical control device according to claim 5, characterized in that: The control system includes a PLC, and the PLC determines and identifies the zero point according to the working mode when the deceleration switch and the extreme speed switch are pressed simultaneously in the zero return mode.

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