Oil seal press packaging error proofing device and oil seal press packaging error proofing method

Abstract

The oil seal press-fitting error-proof device and method can automatically identify the error of the oil seal assembly direction and stop the press-fitting process when the error occurs, thereby avoiding sealing failure, reducing rework and material loss, and improving production efficiency and product reliability.

Description

Technical Field

[0001] This invention relates to the field of automated processing and testing technology, and more specifically, to an oil seal press-fitting error prevention device and a method for oil seal press-fitting error prevention. Background Technology

[0002] Oil seals, as critical sealing elements in mechanical assembly, have a strictly directional structural design. They are typically composed of a metal skeleton and rubber material, with one side being a completely closed end face and the other side having an elastic lip for contacting the rotating shaft. During the press-fitting process, it is essential to ensure that the lip faces the sealing medium. If the orientation is reversed, the lip will not make effective contact with the journal, leading to complete seal failure. This results in continuous oil leakage, abnormal vibration, and premature wear during equipment operation, and in severe cases, can cause a decline in overall machine performance or even render the machine unusable. Currently, in industrial production, oil seal press-fitting devices generally consist of basic components such as a mold frame, cylinder, guide pillars and sleeves, and a moving plate. The workflow relies on manual positioning of the workpiece within the centering sleeve. After the oil seal is placed into the guide sleeve, the cylinder drives the upper tooling to complete the press-fitting action. However, such devices only focus on the mechanical press-fitting function; their internal structure lacks any orientation recognition mechanism and cannot autonomously determine the spatial orientation of the oil seal end face and lip before press-fitting begins. Operators must visually confirm the oil seal orientation during high-speed production. However, due to the miniaturized nature of the oil seals, the visual difference between the end face and lip is slight at certain viewing angles. Furthermore, continuous assembly line work leads to accumulated visual fatigue, significantly increasing the probability of missed inspections. A more prominent problem is the lack of linkage control between the press-fit execution unit and the orientation verification process in existing systems. Even if the operator notices an incorrect assembly, they cannot immediately stop the cylinder's movement, causing the incorrectly assembled oil seal to be forcibly pressed into the workpiece's hole seat. Such errors are often only exposed during subsequent assembly testing or product use. Rework at this point requires disassembling the assembled components, easily causing secondary damage such as oil seal tearing and hole seat scratches. This not only significantly increases material waste and labor costs but also reduces the overall efficiency of the production line. Especially in high-precision assembly scenarios such as automotive gearboxes and motor end covers, incorrect oil seal orientation has become one of the main hidden dangers affecting product reliability, urgently requiring a universal solution that can automatically identify orientation abnormalities at the press-fit source and immediately stop the press-fit process. Summary of the Invention

[0003] This invention provides an oil seal press-fitting error prevention device and method, which can automatically identify oil seal assembly errors and stop the press-fitting process when errors occur, thereby avoiding seal failure, reducing rework and material loss, and improving production efficiency and product reliability.

[0004] To achieve the above objectives, the present invention provides the following technical solution: An oil seal press-fitting error prevention device includes a mold frame, an upper tooling, a middle tooling, a lower tooling, a guide post, a guide sleeve, and a drive cylinder. The upper tooling and the middle tooling are aligned with the lower tooling through the guide post and the guide sleeve. The drive cylinder is fixed on the mold frame and connected to the upper tooling through a cylinder connector. The upper tooling and the middle tooling can move up and down under the action of the drive cylinder and the support spring to perform press-fitting. The upper tooling and / or the lower tooling are provided with a fault-proofing detection component, which includes a fixed sleeve, a guide sleeve, a contact sensor, and an axially floating pin. The guide sleeve and the contact sensor are respectively installed inside the fixed sleeve. The small end of the pin extends out from the end face of the fixed sleeve, and the large end of the pin is positioned opposite to the probe of the contact sensor. The signal output terminal of the contact sensor is electrically connected to the control valve of the drive cylinder; When the small end of the pin is axially pressed against the end face of the oil seal, it can retract into the fixed sleeve and make its large end contact the probe of the contact sensor. When the small end of the pin is inserted into the gap of the oil seal lip, it remains in an extended state and its large end is separated from the probe of the contact sensor.

[0005] The present invention also provides a method for preventing errors during oil seal press-fitting, which includes the following steps: Place the oil seal into the guide sleeve, so that the surface of the oil seal to be tested faces the small end of the pin; If the oil seal is correctly assembled, the end face of the oil seal pushes the small end of the pin to retract it into the fixing sleeve, and the large end of the pin contacts the probe of the contact sensor. The contact sensor closes and connects the power supply circuit of the control valve, and the drive cylinder performs the pressing action. If the oil seal is reversed, the small end of the pin extends into the gap of the oil seal lip and remains extended, while the large end of the pin is separated from the probe of the contact sensor. The contact sensor remains disconnected, the power supply circuit of the control valve is cut off, and the drive cylinder does not perform the pressing action.

[0006] Beneficial effects This invention discloses an oil seal press-fitting error prevention device and method. By integrating error prevention detection components into the upper and / or lower tooling, and utilizing the mechanical-electrical linkage mechanism of pins and contact sensors, the spatial orientation of the oil seal end face and lip is detected in real time. Press-fitting is triggered only when the orientation is correct, effectively blocking the incorrect assembly process. It can automatically identify oil seal assembly errors and stop the press-fitting process when errors occur, thereby avoiding seal failure, reducing rework and material loss, and improving production efficiency and product reliability. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a schematic diagram of the oil seal press-fitting error prevention device according to an embodiment of the present invention; Figure 2 This is a flowchart of the oil seal press-fitting error prevention method according to an embodiment of the present invention.

[0009] Figure label: Oil seal press-fitting error prevention device 100, mold frame 101, support spring 111; upper tooling 102, upper moving plate 112, positioning sleeve 122; middle tooling 103, lower moving plate 113, centering sleeve 123; lower tooling 104, base centering sleeve 114; guide post 105, guide sleeve 106, drive cylinder 107, cylinder connector 117, control valve 127; Error-proof detection component 108, fixing sleeve 118, guide sleeve 128, contact sensor 138, pin 148. Detailed Implementation

[0010] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0011] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0012] like Figure 1As shown, this application proposes an oil seal press-fitting error prevention device 100, including a mold frame 101, an upper tooling 102, a middle tooling 103, a lower tooling 104, a guide post 105, a guide sleeve 106, and a drive cylinder 107. The upper tooling 102 and the middle tooling 103 are aligned with the lower tooling 104 through the guide post 105 and the guide sleeve 106. The drive cylinder 107 is fixed on the mold frame 101 and connected to the upper tooling 102 through a cylinder connector 117. The upper tooling 102 and the middle tooling 103 can move up and down under the action of the drive cylinder 107 and the support spring 111 to perform press-fitting. The upper tooling 102 and / or the lower tooling 104 are provided with a fault-proofing detection component 108, which includes a fixed sleeve 118, a guide sleeve 128, a contact sensor 138, and an axially floating pin 148. The guide sleeve 128 and the contact sensor 138 are respectively installed inside the fixed sleeve 118. The small end of the pin 148 extends out from the end face of the fixed sleeve 118, and the large end of the pin 148 is positioned opposite to the probe of the contact sensor 138. The signal output terminal of the contact sensor 138 is electrically connected to the control valve 127 of the drive cylinder 107; When the small end of the pin 148 is axially pressed against the end face of the oil seal, it can retract into the fixed sleeve 118 and make its large end contact the probe of the contact sensor 138. When the small end of the pin 148 is inserted into the gap of the oil seal lip, it remains in an extended state and its large end is separated from the probe of the contact sensor 138.

[0013] Specifically, the press-fitting execution platform in this embodiment is constructed from a mold frame 101, an upper tooling 102, a middle tooling 103, a lower tooling 104, a guide post 105, a guide sleeve 106, and a drive cylinder 107. The drive cylinder 107 is fixedly mounted on the top of the mold frame 101. The output end of the drive cylinder 107 is directly connected to the upper tooling 102 via a cylinder connector 117 to transmit axial thrust to the tooling. The upper tooling 102 and the middle tooling 103 are fitted onto the guide post 105, and axial forward movement relative to the lower tooling 104 is achieved through the guide sleeve 106. Under the combined action of the thrust applied by the drive cylinder 107 and the elastic support provided by the support spring 111, the upper tooling 102 and the middle tooling 103 move up and down to perform the press-fitting stroke. The workpiece to be pressed is placed directly on the bearing platform of the middle tooling 103, with both ends of the workpiece corresponding to the upper tooling 102 and the lower tooling 104 respectively, to receive the pressing of the oil seal.

[0014] An error-proofing detection component 108 is integrated inside the press-fitting fixture. This component can be installed alone in the upper fixture 102, alone in the lower fixture 104, or simultaneously in both fixtures. The error-proofing detection component 108 uses the fixing sleeve 118 as a mounting base. The guide sleeve 128 and the contact sensor 138 are respectively installed within the internal cavity of the fixing sleeve 118. The guide sleeve 128 is coaxially fixed in the inner hole of the fixing sleeve 118 by press-fitting. A pin 148 is inserted into the guide sleeve 128, forming an axial guide pair, allowing the pin 148 to float freely along the axial direction.

[0015] In practical applications, the pin 148 is manufactured as a stepped shaft structure with different cross-sectional dimensions, including a small end at the front end and a large end at the rear end. The small end of the pin 148 passes through the opening at the end of the retaining sleeve 118 and protrudes beyond the end face of the retaining sleeve 118, serving as a contact for directly probing the surface features of the oil seal. The contact sensor 138 is mounted inside the retaining sleeve 118 and located behind the pin 148, with the probe of the contact sensor 138 arranged axially opposite to the large end of the pin 148. In the initial state without external pressure, the pin 148 remains naturally extended under its own weight, and a separation gap is maintained between the large end of the pin 148 and the probe of the contact sensor 138.

[0016] In addition, the signal output terminal of the contact sensor 138 is electrically connected to the control valve 127 of the drive cylinder 107 to form a control loop between the detection signal and the pneumatic actuation action.

[0017] In practical applications, one possible implementation is that a single contact sensor 138 can be installed inside the fixed sleeve 118, and the contact sensor 138 is directly connected in series in the power supply circuit of the control valve 127. When the oil seal is placed into the guide sleeve 128 in the correct direction, the closed end face of the oil seal faces the small end of the pin 148. During the downward contact process of the upper tooling 102, the closed end face of the oil seal axially presses against the small end of the pin 148, pushing the pin 148 to retract into the fixed sleeve 118 against its own weight, thereby causing the large end of the pin 148 to press against the probe of the contact sensor 138. The contact sensor 138 is triggered to close, thereby connecting the power supply circuit of the control valve 127 and driving the cylinder 107 to continue performing the pressing action. Conversely, when the oil seal is installed in the wrong direction, the side of the oil seal with the lip gap faces the small end of the pin 148. During the downward contact of the upper tooling, the small end of the pin 148 directly penetrates into the lip gap of the oil seal without being axially pushed. The pin 148 remains in an axially extended state, and the large end of the pin 148 continues to be separated from the probe of the contact sensor 138. The contact sensor 138 remains in an open state, the power supply circuit of the control valve 127 is cut off, and the action of the drive cylinder 107 is stopped, thereby preventing the downward movement at the beginning of the press-fitting stage.

[0018] In this embodiment, the error prevention detection component 108 converts the geometric difference between the closed end face and the open lip of the oil seal into the axial displacement of the pin 148, and directly controls the opening and closing of the control valve 127 of the drive cylinder 107 via the contact sensor 138, thus establishing a logical interlock between mechanical displacement and pneumatic actuation. This achieves automatic identification of the oil seal assembly direction before press-fitting starts, eliminating assembly direction errors caused by manual visual inspection, and preventing seal failure, component damage, and disassembly and repair caused by oil seal from the source.

[0019] In another embodiment, two contact sensors 138 are provided inside the fixed sleeve 118, and the two contact sensors 138 are connected in series with the control valve 127 in the same power supply circuit; when both contact sensors 138 are closed by contacting the large end of the pin 148, the power supply circuit is turned on to open the control valve 127.

[0020] Specifically, the contact sensor 138, as a basic detection element that converts mechanical contact displacement into electrical signal on / off state, can take the form of a mechanical micro switch, limit switch, or metal contact displacement sensor. The large end of the pin 148 physically touches the probe to change the switching state of the internal circuit of the sensor, thereby providing a clear on / off judgment benchmark for the circuit.

[0021] In practical applications, the two contact sensors 138 can be symmetrically distributed on both sides of the axis of the large end of the pin 148, or arranged at a certain angle along the radial direction of the end face of the large end of the pin 148, so as to ensure that the probes of the two contact sensors 138 can stably and balancedly contact the end face of the large end of the pin 148, thereby realizing multi-position synchronous monitoring of the axial movement state of the pin 148.

[0022] The power supply circuit serves as a control path for supplying driving power to the control valve 127 of the drive cylinder 107. It can be connected to a DC low-voltage power supply or an AC control power supply. The two contact sensors 138 connected in series in the circuit constitute two independent circuit-breaking control points on the power supply circuit, which together determine the energized and de-energized state of the coil of the control valve 127.

[0023] The technical solution of this embodiment significantly improves the redundancy and reliability of error-proof detection by introducing dual-sensor series logic. Two contact sensors 138 are set in the error-proof detection component 108 and connected in series with the control valve 127. This means that the power supply circuit of the control valve 127 will only be activated when both contact sensors 138 simultaneously detect the contact signal at the large end of the pin 148. This design requires both contact sensors 138 to be in the closed state simultaneously, i.e., both must simultaneously confirm that the oil seal end face has correctly pressed the pin 148 before triggering the drive cylinder 107 to perform the pressing action. Through this dual verification mechanism, the risk of false triggering caused by a single sensor due to mechanical failure, poor contact due to contact oxidation, or accidental vibration interference is effectively avoided. When either contact sensor 138 is not closed, the power supply circuit is in the open state, thus ensuring that the pressing action is only allowed to be executed when the oil seal direction is completely correct and the detection signals are highly consistent. This further strengthens the rigor and stability of the press-fit error prevention from the hardware circuit logic level.

[0024] In another embodiment, two contact sensors are provided inside the fixed sleeve 118, and the two contact sensors 138 are connected in parallel with the control valve 127 in the same power supply circuit; when any of the contact sensors 138 is closed by contact with the large end of the pin 148, the power supply circuit is turned on to open the control valve 127.

[0025] In practical applications, in this embodiment, the input terminals of the two contact sensors 138 are electrically connected to the positive terminal of the power supply, and the output terminals are connected together to the controlled trigger terminal or the input terminal of the drive coil of the control valve 127; or, the two contact sensors 138 are respectively connected to two parallel relay drive branches, and then the control circuit is connected in parallel through the normally open contacts of their respective relays, thereby forming an "OR" logic path in the electrical circuit, ensuring that as long as any branch is closed due to mechanical contact, a complete conduction power supply path can be provided to the control valve 127.

[0026] Through the technical solution of this embodiment, the two contact sensors 138 cooperate spatially to detect the large end of the pin 148, and a parallel redundancy mechanism is constructed at the electrical level. When the oil seal is assembled in the correct direction and pushes the pin 148 into the fixed sleeve 118, the large end of the pin 148 simultaneously moves towards the probes of the two contact sensors 138 and applies axial thrust. During this process, even if one of the contact sensors 138 fails to close normally due to occasional faults such as poor contact caused by long-term vibration, fretting wear, or surface oil accumulation, as long as the other contact sensor 138 normally senses the displacement of the pin 148 and closes, the power supply circuit can be smoothly turned on and drive the control valve 127 to open, thereby enabling the drive cylinder 107 to perform normal pressing action. This parallel logic design effectively improves the fault tolerance and robustness of the error-proof detection system of the present invention, and minimizes the accidental shutdown and production cycle interruption caused by single-point sensor failure. It not only ensures the continuity and stability of the automated assembly process, but also ensures reliable error prevention for the identification of the oil seal end face and lip direction.

[0027] In other embodiments, at least two contact sensors 138 are provided inside the fixed sleeve 118, and the multiple contact sensors 138 are electrically connected to the control valve 127 through a logic circuit composed of multiple switching elements. The logic circuit is configured to implement series conduction logic or parallel conduction logic.

[0028] Specifically, the contact sensor 138 serves as a position sensing element, used to accurately sense the axial displacement of the large end of the pin 148. The logic circuit, composed of multiple switching elements, is a circuit structure used to perform logical operations on the status signals output by the multiple contact sensors 138 and control the main execution loop. The switching elements can specifically be normally open / normally closed contacts of electromagnetic relays, solid-state relays, or semiconductor switching devices such as bipolar transistors and field-effect transistors. The logic circuit can use hardware jumpers, toggle switches, or the internal switching topology switching network of the control board to organize the output signals of each contact sensor 138 into a series conduction form of "logical AND" or a parallel conduction form of "logical OR" as needed, to match the opening and closing level signals required by the control valve driving the cylinder.

[0029] Through the technical solution of this embodiment, multiple contact sensors 138 and control valve 127 are connected by a logic circuit composed of multiple switching elements. This allows for flexible configuration of series or parallel conduction logic based on the error-proofing rules for different workpiece oil seals during the pressing process. In scenarios requiring multi-point synchronous levelness verification of the oil seal's circumferential end face, the logic circuit can be configured as a series conduction logic. The power supply circuit is only closed and conducted when all contact sensors 138 distributed within the fixed sleeve are closed by the large end of their corresponding pins 148, ensuring that the cylinder 107 performs pressing only after the oil seal is fully and positively leveled. In scenarios requiring detection of specific asymmetrical end faces or those with local tolerances, the logic circuit can be flexibly configured as a parallel conduction logic. Control valve 127 can be activated as long as the preset triggering conditions are met. Therefore, the logic circuit based on switching elements breaks the limitation of single fixed wiring, significantly improves the logic reconfiguration capability and application compatibility of multi-point error prevention detection circuit, and ensures that the direction of oil seal can be reliably identified under various assembly conditions and prevents incorrect pressure due to reverse installation.

[0030] In other embodiments, a return spring is provided between the large end of the pin 148 and the fixing sleeve 118. The return spring is used to return the pin 148 to the extended state after the press-fitting is completed.

[0031] Specifically, the return spring, serving as an elastic energy storage and reset component, is positioned between the large end of the pin 148 and the fixed sleeve 118. In practical applications, the return spring can be a cylindrical helical spring, or, depending on the installation space requirements, a disc spring or wave spring, etc., can be used. Its material can be spring steel or stainless steel, metals with fatigue resistance, to ensure elastic stability under long-term reciprocating expansion and contraction. In terms of assembly layout, the return spring can be directly sleeved on the outer circumference of the pin 148 and axially confined between the large end of the pin 148 and the inner wall step of the fixed sleeve 118, or accommodated within a spring groove inside the fixed sleeve 118, thereby providing a continuous and stable axial reset thrust for the pin 148.

[0032] According to the technical solution of this embodiment, when performing the press-fitting operation, if the oil seal direction is correct, the oil seal end face axially pushes the small end of the pin 148 into the fixed sleeve 118, and the large end of the pin 148 moves against the spring resistance and compresses the return spring, so that the return spring accumulates elastic potential energy. When the press-fitting action is completed and the tooling and workpiece are no longer in contact, the axial force of the oil seal end face on the small end of the pin 148 is released, and the return spring releases the stored elastic potential energy, pushing the pin 148 to move outward along the axis against the frictional resistance, so that the small end of the pin 148 quickly re-extrudes from the end face of the fixed sleeve 118, and at the same time, the large end of the pin 148 smoothly separates from the probe of the contact sensor 138, so that the detection circuit returns to the initial disconnected state. This design effectively solves the problem of detection failure caused by the pin 148 being stuck in the fixed sleeve 118 after being pressed. It realizes the autonomous, rapid and reliable reset of the pin 148 in continuous operation cycle, and ensures that the error prevention detection component 108 is in the initial standby state before each pressing cycle, which significantly improves the detection stability and assembly safety of the device in automated continuous production.

[0033] In other embodiments, the small end of the pin 148 is provided with a smooth rounded corner, and the small end of the pin 148 is in clearance fit with the guide hole on the fixing sleeve 118. The length of the small end of the pin 148 extending out of the end face of the fixing sleeve 118 is equal to 1 / 3 to 2 / 3 of the gap depth of the oil seal lip.

[0034] In practical applications, the smooth rounded corners at the small end of the pin 148 can be directly machined or milled to form an arc transition surface, or a smooth arc contour can be obtained through surface treatment processes such as fine grinding and polishing. This rounded corner design eliminates the sharp edge of the outer edge of the small end, providing a smooth transition boundary for the pin end face.

[0035] The fixed sleeve 118 has a guide hole for constraining the axial movement of the small end of the pin 148. The small end of the pin 148 and the guide hole are designed with a clearance fit tolerance. For example, a sliding clearance fit or a self-lubricating anti-friction layer can be applied to the mating surface to ensure guiding accuracy while giving the pin 148 a free axial sliding clearance.

[0036] The length of the small end of the pin 148 extending beyond the end face of the retaining sleeve 118 is strictly limited to 1 / 3 to 2 / 3 of the depth of the oil seal lip clearance. In practice, this extension amount can be set according to the specific geometric specifications of the oil seal to be press-fitted, by adjusting the axial position of the large end step surface of the pin 148 or the limiting thickness of the end of the retaining sleeve 118. For example, when the clearance is deep, a lower limit ratio close to 1 / 3 can be selected, and when the clearance is shallow, an upper limit ratio close to 2 / 3 can be selected to adapt to the testing requirements of different types of oil seals.

[0037] Through the technical solution of this embodiment, the smooth rounded corner of the small end of the pin 148 can effectively reduce the contact stress and frictional resistance at the moment of contact with the oil seal. This not only avoids scratching the surface of the oil seal but also guides the pin 148 smoothly into the detection position, preventing the pin 148 from getting stuck due to contact misalignment. At the same time, the clearance fit between the small end of the pin 148 and the guide hole provides the pin 148 with smooth axial movement freedom, ensuring that the pin 148 can sensitively retract when subjected to a slight axial thrust from the end face of the oil seal. The insertion into the fixed sleeve 118 ensures real-time action response. Furthermore, limiting the extension length to 1 / 3 to 2 / 3 of the lip gap depth provides a precise physical identification criterion in terms of structural dimensions. This ensures that when the oil seal is placed in the forward direction, the small end of the pin 148 can be fully compressed and pushed in by the end face to reliably trigger the contact sensor 138. It also ensures that when the oil seal is placed in the reverse direction, the small end of the pin 148 can be completely placed in the lip gap without making accidental contact with the inner bottom surface of the lip. This significantly improves the accuracy and stability of the forward and reverse identification of the oil seal.

[0038] In other embodiments, the upper tooling 102 includes an upper movable plate 112, a positioning sleeve 122, and a fixed sleeve 118. The cylinder connector 117 is connected to the upper movable plate 112 through the positioning sleeve 122. The upper movable plate 112 is connected to the guide sleeve 106 and the fixed sleeve 118. The guide sleeve 128 and the contact sensor 138 are installed in the fixed sleeve 118 through a sensor mounting plate and fasteners.

[0039] Specifically, the upper movable plate 112, as the bearing and motion reference component of the upper tooling 102, can be made of rectangular steel plate, aluminum alloy plate or casting structure, and has assembly through holes or threaded holes that match the guide sleeve 106, positioning sleeve 122 and fixing sleeve 118, so as to realize coaxial constraint and rigid fixation between various structural components.

[0040] The positioning sleeve 122 serves as a transition positioning and load transfer component between the cylinder connector 117 and the upper moving plate 112. It can be a cylindrical bushing with an axial step, a flange positioning sleeve, or a conical self-centering sleeve. It is used to ensure that the axial driving force output by the drive cylinder 107 can be applied vertically and evenly to the upper moving plate 112, avoiding off-center loading.

[0041] In practical applications, the sensor mounting plate serves as the positioning and support base for the contact sensor 138 inside the fixed sleeve 118. It can be a metal plate with pre-set mounting holes, an L-shaped support bracket, or an adjustable mounting plate with a fine-tuning groove. This provides a stable axial positioning reference for the contact sensor 138 and prevents it from axially moving or radially displacing during operation.

[0042] Fasteners are used to achieve mechanical locking between the guide sleeve 128, the contact sensor and the sensor mounting plate and the fixed sleeve 118. In practical applications, internal hexagonal head screws, double-ended studs with lock nuts, or combination bolts with anti-loosening washers can be used to improve the connection vibration resistance under continuous reciprocating motion conditions.

[0043] The technical solution of this embodiment integrates the drive mechanism, guide mechanism, and error-proof detection component 108 into the upper tooling 102 through a modular structural layout. The cooperation between the positioning sleeve 122 and the upper moving plate 112 ensures that the axial thrust applied by the drive cylinder 107 can be transmitted smoothly and vertically, eliminating off-center load torque. The sensor mounting plate and fasteners rigidly constrain the guide sleeve 128 and contact sensor 138 within the fixed sleeve 118, effectively resisting the influence of high-speed reciprocating motion and pressing impact on the installation position of the contact sensor 138, avoiding probe displacement or signal failure caused by vibration. Simultaneously, the fixed sleeve 118 and guide sleeve 106 are connected together to the upper moving plate 112, ensuring that the error-proof detection action and the pressing downward action are strictly coaxial and synchronized, guaranteeing real-time acquisition of the oil seal direction status during the pressing action, significantly improving the structural integration, operational stability, and reliability of the error-proof detection of the device.

[0044] In another embodiment, the tooling 103 includes a lower moving plate 113 and a centering sleeve 123. The lower moving plate 113 is connected to the guide sleeve 106, and the centering sleeve 123 is disposed on the lower moving plate 113 for positioning the workpiece to be pressed.

[0045] Specifically, the lower moving plate 113, as the core plate-shaped structural component that supports the workpiece and guides its movement, is typically made of structural steel plate or alloy aluminum plate with high structural rigidity. The lower moving plate 113 serves as the movable carrier of the tooling 103, providing a flat and reliable mounting support surface for the centering sleeve 123 and the workpiece. In practical applications, the connection between the lower moving plate 113 and the guide sleeve 106 can be achieved by opening precision mounting holes in the lower moving plate 113 and pressing the guide sleeve 106 into these holes with an interference fit or a transition fit. Alternatively, the guide sleeve 106, with its mounting flange, can be locked and fixed to the end face of the lower moving plate 113 using fastening bolts, ensuring that the lower moving plate 113 can float smoothly and without jamming on the guide post with the help of the guide sleeve 106.

[0046] The centering sleeve 123 is a positioning component used for radial limiting and datum centering of the workpiece to be pressed. The inner cavity or outer contour of the centering sleeve 123 is typically precision-machined according to the geometric positioning characteristics of the workpiece to provide a consistent clamping and positioning datum. In practical applications, the centering sleeve 123 can adopt a stepped through-hole sleeve structure, where the stepped surface of the inner hole precisely fits against the outer edge of the workpiece to achieve radial centering and axial support; or it can adopt an annular bushing with a centering guide angle or countersunk hole positioning structure, utilizing the inner wall of the countersunk hole to achieve rapid alignment with the workpiece positioning surface. For assembly and fixing, the centering sleeve 123 can be rigidly fixed to the upper part of the lower moving plate from the end face using countersunk bolts and positioning pins, or it can be screwed onto the lower moving plate using a threaded connection to ensure its coaxiality with the pressing axis.

[0047] Through the technical solution of this embodiment, a rigid positioning system in which the lower moving plate 113 and the centering sleeve 123 cooperate with each other is constructed in the tooling 103, establishing a precise physical reference for the oil seal pressing process. Since the centering sleeve 123 is fixedly set on the lower moving plate 113, it can forcibly center and constrain the workpiece to be pressed, effectively eliminating the positional deviation during the workpiece placement process and the lateral swaying under the pressing impact; at the same time, the connection between the lower moving plate 113 and the guide sleeve 106 enables the tooling 103 to maintain high-precision coaxial movement with the entire mold frame guiding system, thereby ensuring that the workpiece to be pressed, the oil seal, and the error prevention detection component 108 are always in a strictly coaxial state. Based on this, it is precisely because of the precise positioning of the centering sleeve 123 on the workpiece to be pressed that the pin 148 can be strictly aligned with the detection trajectory of the oil seal lip gap, completely avoiding the misjudgment phenomenon that the pin 148 may accidentally press the oil seal end face or enter the non-gap area due to workpiece misalignment, and significantly improving the triggering accuracy of the error prevention detection component 108 and the centering stability of the pressing operation.

[0048] In other embodiments, the lower tooling 104 includes a base centering sleeve 114 and a fixing sleeve 118. The fixing sleeve 118 is fixedly connected to the mold frame 101 through the base centering sleeve 114. The fixing sleeve 118 is provided with a guide sleeve 128, a contact sensor 138 and a pin 148 for pressing the lower end of the workpiece with an oil seal.

[0049] Specifically, the base centering sleeve 114 serves as a mounting base and positioning component, primarily providing stable mounting support and a reference positioning surface. In practical applications, the base centering sleeve 114 can be rigidly assembled onto the corresponding platform of the mold frame 101 via mechanical connections such as bolt fastening, flange clamping, or pin positioning. Its material is typically structural steel or mold steel with high rigidity and fatigue resistance, so as to stably withstand the vertical pressing load from the upper tooling and workpiece during the pressing process.

[0050] The fixing sleeve 118 serves as a housing component for accommodating the detection components. Its main function is to provide rigid housing space for the internal detection elements and ensure the coaxiality and spatial positional relationship of each element. In practical applications, the fixing sleeve 118 can adopt a cylindrical stepped sleeve structure and be directly embedded in the inner hole of the base centering sleeve 114, achieving relative fixation with the base centering sleeve 114 through threaded locking; alternatively, the fixing sleeve 118 can also be integrated into the base centering sleeve 114 using an interference fit, transition fit, and a retaining ring for positioning, thus forming an independent functional module that facilitates overall maintenance and replacement.

[0051] The guide sleeve 128, contact sensor 138, and pin 148, all located inside the fixed sleeve 118, jointly provide error-proof detection at the lower end. The guide sleeve 128 provides concentric guidance when the oil seal enters the workstation; the contact sensor 138 converts mechanical displacement into an electrical signal output, and can be a mechanical micro-motion contact switch, limit switch, or stylus sensor; the pin 148, as a key mechanical sensing and force transmission element, has a large end and a small end with different outer diameters, allowing it to float freely axially within the fixed sleeve 118.

[0052] Through the technical solution of this embodiment, the error prevention detection component 108, which includes guide sleeve 128, contact sensor 138 and pin 148, is directly integrated into the fixing sleeve 118 and base centering sleeve 114 of the lower tooling 104, so that the lower tooling 104 can carry the workpiece to be pressed and install while having the ability to perform real-time detection of the oil seal to be installed at the lower end of the workpiece. When pressing the oil seal onto the lower end of the workpiece, the oil seal is placed inside the guide sleeve 128 of the lower tooling 104. If the oil seal is placed in the correct direction, the closed end face of the oil seal directly pushes against the small end of the pin 148, forcing the pin 148 to retract axially into the fixed sleeve 118. This allows the large end of the pin 148 to make close contact with the probe of the contact sensor 138 to conduct the circuit, and the drive cylinder 107 then performs the downward pressing action. Conversely, if the oil seal is installed in the wrong direction, the small end of the pin 148 extends directly into the gap of the oil seal lip and remains extended. The large end of the pin 148 cannot touch the probe of the contact sensor 138, the control circuit remains open, and the pressing action of the drive cylinder 107 is directly blocked. This structural arrangement effectively eliminates the detection blind spot during the pressing process of the oil seal on the lower end of the workpiece, ensuring the accuracy and safety of the lower end oil seal assembly direction.

[0053] In other implementations, such as Figure 2 As shown, the present invention also discloses an oil seal press-fitting error prevention method, which employs an oil seal press-fitting error prevention device as described in the embodiments of the present invention, and includes the following steps: S201: Place the oil seal into the guide sleeve 128, so that the surface of the oil seal to be tested faces the small end of the pin 148; This step is mainly used to establish the initial positioning reference between the oil seal and the testing mechanism. Specifically, the oil seal can be inserted manually by the operator along the inner hole of the guide sleeve, or it can be accurately transferred and installed into the guide sleeve by an automated positioning device such as an industrial robotic arm, pneumatic gripper, or vibratory feeder, to ensure that the geometry of the oil seal being tested is aligned with the small end of the pin.

[0054] S202: If the oil seal is correctly assembled, the oil seal end face pushes the small end of the pin 148 to retract it into the fixing sleeve 118, and the large end of the pin 148 contacts the probe of the contact sensor 138. The contact sensor 138 closes and conducts the power supply circuit of the control valve 127, and the drive cylinder 107 performs the pressing action. This step mainly utilizes the continuous, flat contour of the oil seal's closed end face to apply axial mechanical thrust to the pin 148. The specific implementation of the interaction between the large end of the pin 148 and the contact sensor 138 probe can be achieved by the large end of the pin 148 directly physically pressing against the mechanical micro-switch probe to close the internal normally open contact; alternatively, the large end of the pin 148 can approach the sensing area of ​​a proximity, photoelectric, or magnetic probe to trigger the internal semiconductor switch to conduct. The conducting circuit directly or indirectly powers the solenoid coil of the control valve, thereby switching the air path to drive the cylinder to extend and perform the oil seal pressing action.

[0055] S203: If the oil seal is reversed, the small end of the pin 148 extends into the gap of the oil seal lip and remains extended, the large end of the pin 148 is separated from the probe of the contact sensor 138, the contact sensor 138 remains in the open state, the power supply circuit of the control valve 127 is cut off, and the drive cylinder 107 does not perform the pressing action.

[0056] This step primarily utilizes the lip structure with an annular cavity on the open side of the oil seal to provide axial clearance. When the oil seal is reversed, the small end of the pin 148 smoothly extends into the internal gap of the lip without being pressed by the end face, while the large end of the pin 148 remains physically detached from the probe of the contact sensor 138, keeping the control circuit in an open-circuit state. Regarding the method of power supply circuit disconnection, it can be directly connected in series to the electromagnet power supply line of the control valve 127 to form a hardware-level physical power cutoff, or it can be transmitted as an interlock input signal to a programmable logic controller (PLC) or relay interlock module for program-level logic blocking, thereby forcibly prohibiting the air path reversal and action issuance of the drive cylinder 107.

[0057] This embodiment achieves a deep physical and logical interlock between the geometric features of the oil seal and the electrical circuit of the press-fitting power system, constructing a closed-loop control system from detection to execution. Since the axial mechanical displacement of the pin 148 directly determines the opening and closing state of the contact sensor 138, the control valve 127 circuit is only allowed to conduct and drive the cylinder to perform press-fitting when the oil seal is oriented correctly and the flat end face firmly pushes the pin 148 to trigger the sensor closure. If the oil seal is reversed, the small end of the pin 148 falls into the lip gap and cannot trigger the sensor, resulting in a naturally disconnected power supply circuit, cutting off the power source of the actuator at its source. This method eliminates reliance on manual visual identification and experience-based judgment, completely preventing reverse pressing due to misoperation or signal response delays, effectively avoiding mechanical damage to the workpiece and oil seal, and significantly improving the automation and error prevention level and assembly quality consistency of the oil seal press-fitting process.

[0058] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of this application.

[0059] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

Claims

1. An oil seal press-fitting error prevention device, comprising a mold frame, an upper tooling, a middle tooling, a lower tooling, a guide post, a guide sleeve, and a drive cylinder, wherein the upper tooling and the middle tooling are aligned with the lower tooling through the guide post and the guide sleeve, the drive cylinder is fixed on the mold frame and connected to the upper tooling through a cylinder connector, and the upper tooling and the middle tooling can move up and down under the action of the drive cylinder and the support spring to perform press-fitting; Its features are, The upper tooling and / or the lower tooling are provided with a fault-proofing detection component, which includes a fixed sleeve, a guide sleeve, a contact sensor, and an axially floating pin. The guide sleeve and the contact sensor are respectively installed inside the fixed sleeve. The small end of the pin extends out from the end face of the fixed sleeve, and the large end of the pin is positioned opposite to the probe of the contact sensor. The signal output terminal of the contact sensor is electrically connected to the control valve of the drive cylinder; When the small end of the pin is axially pressed against the end face of the oil seal, it can retract into the fixed sleeve and make its large end contact the probe of the contact sensor. When the small end of the pin is inserted into the gap of the oil seal lip, it remains in an extended state and its large end is separated from the probe of the contact sensor.

2. The oil seal press-fitting error prevention device according to claim 1, characterized in that, Two contact sensors are provided inside the fixed sleeve, and the two contact sensors are connected in series with the control valve in the same power supply circuit; when both contact sensors are closed by the large end of the pin, the power supply circuit is turned on to open the control valve.

3. The oil seal press-fitting error prevention device according to claim 1, characterized in that, Two contact sensors are provided inside the fixed sleeve, and the two contact sensors are connected in parallel with the control valve in the same power supply circuit; when either contact sensor is closed by the large end of the pin, the power supply circuit is turned on to open the control valve.

4. The oil seal press-fitting error prevention device according to claim 1, characterized in that, At least two of the contact sensors are provided inside the fixed sleeve. The multiple contact sensors are electrically connected to the control valve through a logic circuit composed of multiple switching elements. The logic circuit is configured to implement series conduction logic or parallel conduction logic.

5. The oil seal press-fitting error prevention device according to any one of claims 1 to 4, characterized in that, A return spring is provided between the large end of the pin and the fixed sleeve. The return spring is used to return the pin to the extended state after the press-fitting is completed.

6. The oil seal press-fitting error prevention device according to any one of claims 1 to 5, characterized in that, The small end of the pin is provided with a smooth rounded corner. The small end of the pin is in clearance fit with the guide hole on the fixed sleeve. The length of the small end of the pin extending out of the end face of the fixed sleeve is equal to 1 / 3 to 2 / 3 of the gap depth of the oil seal lip.

7. The oil seal press-fitting error prevention device according to any one of claims 1 to 6, characterized in that, The upper tooling includes an upper movable plate, a positioning sleeve, and a fixed sleeve. The cylinder connector is connected to the upper movable plate through the positioning sleeve. The upper movable plate is connected to the guide sleeve and the fixed sleeve. The guide sleeve and the contact sensor are installed in the fixed sleeve through a sensor mounting plate and fasteners.

8. The oil seal press-fitting error prevention device according to any one of claims 1 to 7, characterized in that, The tooling includes a lower moving plate and a centering sleeve. The lower moving plate is connected to the guide sleeve, and the centering sleeve is disposed on the lower moving plate for positioning the workpiece to be pressed.

9. The oil seal press-fitting error prevention device according to any one of claims 1 to 8, characterized in that, The lower tooling includes a base centering sleeve and a fixing sleeve. The fixing sleeve is fixedly connected to the mold frame through the base centering sleeve. The fixing sleeve is provided with a guide sleeve, a contact sensor and a pin for pressing oil seals onto the lower end of the workpiece.

10. A method for preventing errors in oil seal press-fitting, employing the oil seal press-fitting error-prevention device as described in any one of claims 1 to 9, characterized in that, Includes the following steps: Place the oil seal into the guide sleeve, so that the surface of the oil seal to be tested faces the small end of the pin; If the oil seal is correctly assembled, the end face of the oil seal pushes the small end of the pin to retract it into the fixing sleeve, and the large end of the pin contacts the probe of the contact sensor. The contact sensor closes and connects the power supply circuit of the control valve, and the drive cylinder performs the pressing action. If the oil seal is reversed, the small end of the pin extends into the gap of the oil seal lip and remains extended, while the large end of the pin is separated from the probe of the contact sensor. The contact sensor remains disconnected, the power supply circuit of the control valve is cut off, and the drive cylinder does not perform the pressing action.

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