Dual-Branch Combined Plunger Pump with Built-In Oil Circuit and Riveting Tool

This application is a continuation application of PCT application No. PCT/CN2024/088790, filed on Apr. 19, 2024, which claims priority to Chinese Patent Application No. 202410447132.2, filed on Apr. 15, 2024. The entire disclosures of the aforementioned applications are incorporated herein by reference in their entireties.

The present disclosure relates to the technical field of riveting tools, and in particular to a dual-branch combined plunger pump with a built-in oil circuit and a riveting tool.

The existing electric-hydraulic riveting tools, such as that described in Chinese Patent Application Publication No. CN115319009A, generally comprises components including a combined plunger pump, crankshaft, main body, riveting working head, motor, and oil tank. The motor drives the crankshaft to rotate, which in turn pushes the plungers within the combined plunger pump to pressurize the hydraulic oil. The oil then flows through the main body into the riveting working head, where it controls the movement of the piston within the working head.

Among these components, the existing combination plunger pump, such as that described in Chinese Patent Application Publication No. CN218207040U, includes low-pressure and high-pressure oil outlet channels, with both outlets arranged on the same side, for connection with the crankshaft chamber on the main body.

However, since the existing combined plunger pump has an oil inlet on the side wall for connection with the oil tank via an oil pipe, this setup is prone to oil leakage due to the oil pipe placed outside the oil tank and the combined plunger pump. Such leakage can result in the riveting tool failing to function properly.

The present disclosure provides a dual-branch combined plunger pump with a built-in oil circuit and a riveting tool, which do not require an oil pipe to connect the oil tank and the combined plunger pump, thus oil leakage can be effectively reduced, thereby effectively extending the service life of the riveting tool and reducing the maintenance frequency.

In order to solve the above technical problems, the present disclosure adopts the proposals as follows.

In a first aspect, provided is a dual-branch combined plunger pump with a built-in oil circuit adapted for outputting oil to drive a piston in a riveting work head to move, including a pump body, a plunger being arranged in the pump body, a plunger chamber for the plunger to move being provided on the pump body, and the pump body being provided with an oil inlet on a wall surface where an outlet of the plunger chamber is located for communicating with a crankshaft chamber on a main body. By arranging the oil inlet on the wall surface where the outlet of the plunger chamber is located, the oil inlet is in direct communication with the crankshaft chamber, so that the oil in the crankshaft chamber can directly enter the pump body through the oil inlet. In the existing technology, the wall surface where the outlet of the plunger chamber is located is in a sealed connection with the main body, thus there is no need to set up an additional oil pipe to transport the oil in the oil tank to the pump body, thereby avoiding the oil leakage at the oil pipe and effectively extending the service life of the riveting tool adopting the combined plunger pump. Moreover, since the oil intake of the pump body is achieved by the pressure difference between the inside and outside of the pump body, the resistance of the oil circuit is proportional to the length of the path and inversely proportional to the cross-sectional area of the channel. When the oil pipe is connected with the pump body, the oil inlet path of the pump body is relatively long and the cross-section of the oil inlet is relatively small, which will reduce the oil inlet efficiency of the pump body. By omitting the oil pipe and arranging the oil inlet on the wall surface where the outlet of the plunger chamber is located, the length of the oil inlet path can be effectively reduced, thereby improving the oil inlet efficiency of the pump body and improving the overall volumetric efficiency of the hydraulic system under high-speed operation.

Further, the pump body is provided with a boss for embedding into the crankshaft chamber in the main body, and an outlet of the plunger chamber and the oil inlet are both arranged on the boss. The arrangement of the boss allows a plane where the oil inlet is located to be entirely received in the crankshaft chamber, further avoiding the oil leakage.

Further, an oil inlet channel is provided between the oil inlet and the plunger chamber, and the plunger chamber is communicated with an oil outlet channel, and the outlet of the oil outlet channel faces outward from the pump body in a same direction as the oil inlet. The arrangement of the oil outlet channel allows the oil pressurized by the plunger within the plunger chamber to be transported into the main body, facilitating the driving of the riveting work head communicated with the main body.

Further, the plunger includes a high-pressure pump plunger and a low-pressure pump plunger, the plunger chamber includes a high-pressure chamber for movement of the high-pressure pump plunger and a low-pressure chamber for movement of the low-pressure pump plunger. The oil inlet channel is in communication with the low-pressure chamber, the oil outlet channel includes a high-pressure oil outlet circuit and a low-pressure oil outlet circuit, the low-pressure oil outlet circuit is only in communication with the low-pressure chamber, and the low-pressure chamber and the high-pressure chamber are both in communication with the high-pressure oil outlet circuit. Through the design of the high-pressure pump plunger, the low-pressure pump plunger, the high-pressure chamber, the low-pressure chamber, the high-pressure oil outlet circuit, the low-pressure oil outlet circuit, the oil inlet channel and their interconnections, the oil can enter the low-pressure chamber via the oil inlet channel and be pressurized by the low-pressure pump plunger driven by the crankshaft, the oil pressurized by the low-pressure pump plunger enters the low-pressure oil outlet circuit and is discharged from the pump body into the main body. Alternatively, the oil pressurized by the low-pressure pump plunger enters the high-pressure chamber via the high-pressure oil outlet circuit and is further pressurized by the high-pressure pump plunger before being discharged through the high-pressure oil outlet circuit into the main body.

Further, the outlet of the oil outlet channel includes a low-pressure oil outlet and a high-pressure oil outlet, the low-pressure oil outlet is in communication with the low-pressure oil outlet circuit, the high-pressure oil outlet is in communication with the high-pressure oil outlet circuit, and the low-pressure oil outlet and the high-pressure oil outlet are both located on a face of the pump body on which the boss is located. By arranging the low-pressure oil outlet and the high-pressure oil outlet on the side of the pump body provided with the boss, the low-pressure oil outlet and the high-pressure oil outlet can be closely fitted on a wall surface on the main body and communicated with the oil channel in the main body when the pump body is mounted on the main body.

Further, the oil inlet channel is provided with an oil inlet check valve that allows oil to be transported only from the oil inlet to the low-pressure chamber, the low-pressure oil outlet circuit is provided with a low-pressure pressurized oil check valve that allows oil to be transported only from the low-pressure chamber to the low-pressure oil outlet, and the high-pressure oil outlet circuit is provided with a transition check valve located between the low-pressure chamber and the high-pressure chamber that allows oil to be transported only from the low-pressure chamber to the high-pressure chamber, and a high-pressure pressurized oil check valve located between the high-pressure chamber and the high-pressure oil outlet that allows oil to be transported only from the high-pressure chamber to the high-pressure oil outlet. Each check valve adopts the existing technology. The low-pressure chamber is provided with a return spring for ejecting the low-pressure pump plunger out of the low-pressure chamber. During rotation of the crankshaft, the crankshaft moves away from the high-pressure pump plunger while the crankshaft approaches the low-pressure pump plunger, and the crankshaft approaches the high-pressure pump plunger when the crankshaft moves away from the low-pressure pump plunger. With the configuration of each check valve including the oil inlet check valve, the low-pressure pressurized oil check valve, the transition check valve and the high-pressure pressurized oil check valve, the oil in each oil circuit within the pump body can flow in one direction.

Further, the oil inlet is located between outlets of the high-pressure chamber and the low-pressure chamber on the boss. Since the high-pressure chamber and the low-pressure chamber need to be separated by a distance, the space between the high-pressure chamber and the low-pressure chamber can be reasonably utilized by positioning the oil inlet between the high-pressure chamber and the low-pressure chamber. This can more effectively reduce the overall volume of the combined plunger pump compared to placing the oil inlet outside the integrated structure formed by the high-pressure chamber and the low-pressure chamber.

Further, the oil inlet channel is arranged in parallel with the high-pressure chamber and the low-pressure chamber, the oil inlet channel is arranged between the high-pressure chamber and the low-pressure chamber, and an end of the oil inlet channel away from the oil inlet is communicated with the low-pressure chamber. The spatial relationship between the oil inlet channel, the high-pressure chamber and the low-pressure chamber facilitates the oil to enter the oil inlet channel from the front side of the oil inlet.

Further, an inner diameter of the low-pressure chamber is larger than an inner diameter of the high-pressure chamber, and the low-pressure oil outlet circuit and the high-pressure oil outlet circuit are respectively located on opposite sides of the integrated structure formed by the low-pressure chamber, the oil inlet channel, and the high-pressure chamber. The low-pressure oil outlet circuit is communicated with a bottom end of the low-pressure chamber, and the bottom ends of the high-pressure chamber and the low-pressure chamber are both communicated with the high-pressure oil outlet circuit. Through the design of the size of the low-pressure chamber and the high-pressure chamber, the high-pressure chamber can output oil with higher pressure as the crankshaft rotates to output the same thrust to the high-pressure pump plunger and the low-pressure pump plunger. Through the design of the spatial position of the low-pressure oil outlet circuit and the high-pressure oil outlet circuit, the space of the integrated structure formed by the oil inlet channel, the low-pressure chamber, the high-pressure chamber, the low-pressure oil outlet circuit, and the high-pressure oil outlet circuit can be reduced as much as possible, thereby reducing the volume of the pump body and saving space.

In a second aspect, provided is a riveting tool including a main body, an oil tank and a crankshaft chamber being arranged in the main body, the oil tank being communicated with the crankshaft chamber, a plunger port for a plunger to move being arranged on a side face of the main body, and a wall surface of the main body on which the plunger port is located being sealed with the above-mentioned dual-branch combined plunger pump with a built-in oil circuit, and the oil inlet being communicated with the crankshaft chamber. By arranging the oil inlet in communication with the crankshaft chamber, the path of the oil in the existing technology that passes through the oil tank, oil pipe, and pump body in sequence is modified to a path passing through the oil tank, crankshaft chamber, and pump body. Since sealing is already required between the main body and the pump body, eliminating the external oil pipe reduces the number of areas that require sealing, thereby lowering the risk of oil leakage.

Further, a crankshaft is arranged in the crankshaft chamber, and at least two eccentric wheels are arranged on the crankshaft along an axial direction, and an oil inlet gap is provided between the two eccentric wheels, and the oil inlet gap corresponds to the position of the oil inlet. The spatial relationship between the oil inlet gap and the oil inlet allows the eccentric wheels to avoid the oil inlet, thereby preventing the eccentric wheels from obstructing the oil inlet when rotating, so as to achieve smooth access to the oil inlet in any state of crankshaft.

Further, the plunger port has the same shape as the boss, a sealing gasket sleeved on the boss is arranged between the pump body and the main body, an oil tank is provided on the main body, and the oil tank is communicated with the crankshaft chamber. Through the design of the shape and relative size of the boss and the plunger port, the sealing effect between the pump body and the main body can be improved, preventing oil leakage from the gap where the pump body is mounted.

The present disclosure has the advantageous effects:

Reference signs are as follows:, pump body;, oil inlet;, boss;, oil inlet channel;, high-pressure pump plunger;, low-pressure pump plunger;, high-pressure chamber;, low-pressure chamber;, high-pressure oil outlet circuit;, low-pressure oil outlet circuit;, high-pressure oil outlet;, low-pressure oil outlet;, oil inlet check valve;, low-pressure pressurized oil check valve;, transition check valve;, high-pressure pressurized oil check valve;, main body;, crankshaft chamber;, plunger port;, oil tank;, eccentric wheel; and, oil inlet gap.

The present disclosure will be further described in detail below in conjunction with embodiments and accompanying drawings, but the embodiments of the present disclosure are not limited thereto.

In the description of the present disclosure, it should be noted that the terms “center”, “up”, “down”, “left”, “right”, “vertical”, “longitudinal”, “lateral”, “horizontal”, “inside”, “outside”, “front”, “rear”, “top”, “bottom” and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the inventive product is usually placed when used. They are merely for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present disclosure.

In the description of the present disclosure, it also should be noted that, unless otherwise clearly specified and limited, the terms “disposed”, “opened”, “mounted”, “connected”, and “connection” should be understood in a broad sense, for example, it may be a fixed connection, a detachable connection, or an integrated structure; it may be a mechanical connection or an electrical connection; it may be a direct connection, or it may be indirectly connected through an intermediate medium, or it may be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

In a first aspect, as shown in, a dual-branch combined plunger pump with a built-in oil circuit, adapted for outputting oil to drive a piston in a riveting work head to move, includes a pump body, a plunger is provided in the pump body, and a plunger chamber for the plunger to move is provided in the pump body. The pump bodyis arranged with an oil inleton a wall surface where an outlet of the plunger chamber is located for communicating with a crankshaft chamberon a main body. By arranging the oil inleton the wall surface where the outlet of the plunger chamber is located, the oil inletdirectly communicates with the crankshaft chamber, so that the oil in the crankshaft chambercan directly enter the pump bodythrough the oil inlet. In the existing technology, the wall surface where the outlet of the plunger chamber is located is sealed with the main body, thus there is no need to set up an oil pipe to transport the oil in an oil tank to the pump body, which avoids oil leakage at the oil pipe, thereby effectively extending the service life of a riveting tool using the combined plunger pump. Moreover, since the oil intake of the pump bodyis achieved through the pressure difference between the inside and outside of the pump body, the resistance of the oil circuit is proportional to the length of the path and inversely proportional to the cross-sectional area of the channel. When the oil pipe is communicated with the pump body, the oil inlet path of the pump bodyis relatively long, and the oil inlet cross-section is relatively small, which will decrease the oil intake efficiency of the pump body. By removing the oil pipe and arranging the oil inleton the wall surface where the outlet of the plunger chamber is located, the length of the oil inlet path can be effectively reduced, thereby improving the oil intake efficiency of the pump bodyand improving the overall volumetric efficiency of the hydraulic system under high-speed operation.

Specifically, as shown in, the pump bodyis arranged with a bossfor embedding into the crankshaft chamberon the main body, and the outlet of the plunger chamber and the oil inletare both located on the boss. Through the arrangement of the boss, a plane where the oil inletis located can be completely received within the crankshaft chamber, further avoiding the risk of oil leakage.

Specifically, as shown in, an oil inlet channelis provided between the oil inletand the plunger chamber, and the plunger chamber is communicated with an oil outlet channel, and an outlet of the oil outlet channel faces outward from the pump bodyin the same direction as the oil inlet. Through the arrangement of the oil outlet channel, the oil pressurized by the plunger in the plunger chamber can be transported to the main body, which is conducive to driving a riveting work head communicated with the main body.

Specifically, as shown in, the plunger includes a high-pressure pump plungerand a low-pressure pump plunger, the plunger chamber includes a high-pressure chamberfor the movement of the high-pressure pump plungerand a low-pressure chamberfor the movement of the low-pressure pump plunger. The oil inlet channelis communicated with the low-pressure chamber. The oil outlet channel includes a high-pressure oil outlet channeland a low-pressure oil outlet channel, the low-pressure oil outlet channelis only communicated with the low-pressure chamber, and the low-pressure chamberand the high-pressure chamberare both communicated with the high-pressure oil outlet channel. Through the communication relationship between the high-pressure pump plunger, the low-pressure pump plunger, the high-pressure chamber, the low-pressure chamber, the high-pressure oil outlet channel, the low-pressure oil outlet channel, the oil inlet channel, the oil can enter the low-pressure chamberfrom the oil inlet channeland be pressurized by the low-pressure pump plungerdriven by the crankshaft, and the oil pressurized by the low-pressure pump plungerenters the low-pressure oil outlet channeland is discharged from the pump bodyinto the main body, alternatively, the oil pressurized by the low-pressure pump plungerenters the high-pressure chamberthrough the high-pressure oil outlet channeland, after being further pressurized by the high-pressure pump plunger, is discharged through the high-pressure oil outlet channelfrom the pump bodyinto the main body.

Specifically, as shown in, the outlet of the oil outlet channels includes a low-pressure oil outletand a high-pressure oil outlet, the low-pressure oil outletis communicated with the low-pressure oil outlet circuit, the high-pressure oil outletis communicated with the high-pressure oil outlet circuit, and the low-pressure oil outletand the high-pressure oil outletare both located on a side face of the pump bodyarranged with the boss. By arranging the low-pressure oil outletand the high-pressure oil outleton the side face of the pump bodyarranged with the boss, the low-pressure oil outletand the high-pressure oil outletcan be closely fitted to the wall surface of the main bodyand communicated with the oil channel in the main bodywhen the pump bodyis mounted on the main body.

Specifically, as shown in, the oil inlet channelis provided with an oil inlet check valvethat allows oil to be transported only from the oil inletto the low-pressure chamber, the low-pressure oil outlet circuitis provided with a low-pressure pressurized oil check valvethat allows oil to be transported only from the low-pressure chamberto the low-pressure oil outlet, and the high-pressure oil outlet circuitis provided with a transition check valvelocated between the low-pressure chamberand the high-pressure chamberthat allows oil to be transported only from the low-pressure chamberto the high-pressure chamber, and a high-pressure pressurized oil check valvelocated between the high-pressure chamberand the high-pressure oil outletthat allows oil to be transported only from the high-pressure chamberto the high-pressure oil outlet. Each check valve adopts a ball valve, which is composed of a spherical valve core and a spring (not shown). Four holding frames are evenly arranged in a rectangular array in the oil inlet channel. The four holding frames are parallel to each other, and outer walls of the spherical valve cores in the oil inlet channelare respectively tangent to the four holding frames. The holding frames can prevent the spherical valve cores in the oil inlet channelfrom wobbling. In addition, the holding frames allow the oil inlet check valveto be reset as quickly as possible when it needs to be closed, so that the spherical valve cores in the oil inlet channelcan smoothly block the entrance of the oil inlet channel. A reset spring for ejecting the low-pressure pump plungerout of the low-pressure chamberis provided in the low-pressure chamber. As the crankshaft rotates, the crankshaft approaches the low-pressure pump plunger, while moving away from the high-pressure pump plunger, and the crankshaft moves away from the low-pressure pump plungerwhile approaching the high-pressure pump plunger. The oil in each oil circuit in the pump bodyflows in one direction through the check valves including the oil inlet check valve, the low-pressure oil check valve, the transition check valve, and the high-pressure oil check valve.

Specifically, as shown in, the oil inletis located between outlets of the high-pressure chamberand the low-pressure chamberon the boss. Since the high-pressure chamberand the low-pressure chamberneed to be separated by a distance to separate the high-pressure chamberand the low-pressure chamber, the space between the high-pressure chamberand the low-pressure chambercan be reasonably utilized by positioning the oil inletbetween the high-pressure chamberand the low-pressure chamber. Compared with a configuration in which the oil inletis located outside the integrated structure formed by the high-pressure chamberand the low-pressure chamber, the overall volume of the combined plunger pump can be significantly reduced.

An oil collecting groove is provided between the oil inlet channeland the oil inlet, and a cross-sectional area of the oil collecting groove is larger than a cross-sectional area of the oil inlet channel. The oil collecting groove allows the length of the oil inlet channelto be reduced, thereby reducing the resistance of the oil flow in the oil inlet channel, additionally, the weight of the pump body can be reduced.

Specifically, as shown in, the oil inlet channelis arranged in parallel with the high-pressure chamberand the low-pressure chamber, and the oil inlet channelis located between the high-pressure chamberand the low-pressure chamber. An end of the oil inlet channelaway from the oil inletis communicated with the low-pressure chamber. The design of the spatial relationship between the oil inlet channel, the high-pressure chamberand the low-pressure chamberfacilitates the oil to enter the oil inlet channelthrough a front side of the oil inlet.

Specifically, as shown in, an inner diameter of the low-pressure chamberis larger than an inner diameter of the high-pressure chamber, and the low-pressure oil outlet circuitand the high-pressure oil outlet circuitare respectively located on opposite sides of the integrated structure composed of the low-pressure chamber, the oil inlet channel, and the high-pressure chamber. The low-pressure oil outlet circuitis communicated with a bottom end of the low-pressure chamber, and a bottom end of the high-pressure chamberand the bottom end of the low-pressure chamberare both communicated with the high-pressure oil outlet circuit. Through the design of the relative size between the low-pressure chamberand the high-pressure chamber, when the crankshaft rotates to output the same thrust to the high-pressure pump plungerand the low-pressure pump plunger, the high-pressure chambercan output oil with a higher pressure. Through the design of the spatial position of the low-pressure oil outlet circuitand the high-pressure oil outlet circuit, the space of the integrated structure composed of the oil inlet channel, the low-pressure chamber, the high-pressure chamber, the low-pressure oil outlet circuit, and the high-pressure oil outlet circuitcan be reduced as much as possible, so that the volume of the pump body I can be reduced to save space.

In a second aspect, as shown in, a riveting tool includes a main body, an oil tank and a crankshaft chamberare arranged in the main body, and the oil tank is communicated with the crankshaft chamber. A plunger portfor movement of the plunger is provided on a side face of the main body, and the main bodyis sealed with the above-mentioned dual-branch combined plunger pump with a built-in oil circuit on a wall surface where the plunger portis located. The oil inletis communicated with the crankshaft chamber. With the oil inletcommunicated with the crankshaft chamber, the path of the oil in the existing technology that passes through the oil tank, the oil pipe, and the pump bodyin sequence is modified to a path passing through the oil tank, the crankshaft chamber, and the pump body. Since the main bodyand the pump bodyneed to be sealed, the number of positions that need to be sealed is reduced by omitting the oil pipe, thereby reducing the risk of oil leakage.

Specifically, as shown in, a crankshaft is provided in the crankshaft chamber, and at least two eccentric wheelsare provided on the crankshaft along an axial direction thereof. An oil inlet gapis provided between the two eccentric wheels, and the oil inlet gapcorresponds to the position of the oil inlet. The spatial relationship between the oil inlet gapand the oil inletallows the eccentric wheelsto avoid the oil inlet, thereby preventing the eccentric wheelsfrom obstructing the oil inletduring rotation, thus a smooth access to the oil inletis maintained in any state of the crankshaft.

The plunger porthas the same shape as the boss, and the bossand the plunger portare in an interference fitting. A sealing gasket sleeved outside the bossis arranged between the pump bodyand the main body. An oil tank communicated with the crankshaft chamberis provided on the main body. Through the shape and size of the bossand the plunger port, the pressure of the oil in the crankshaft chamberapplied to the pump bodyis mainly on an end face of the bossarranged with the oil inlet, rather than an end face of the pump bodywith the boss, which ensures sealing effect of the end face of the pump bodyarranged with the boss, so that the pressure of the oil in the gap between the end face of the pump bodyarranged with the bossand the main bodyis small, thereby further improving the sealing effect between the pump bodyand the main body, and preventing the oil from leaking from the gap where the pump bodyis mounted.

The working principle of this embodiment is as follows: the bossof the pump bodyis embedded in the plunger port, so that the pump bodyis in a sealed connection with the main body. The oil in the oil tank first enters the crankshaft chamberand then directly enters the pump bodythrough the oil inlet. Low-pressure oil discharged from the low-pressure oil outletis the oil that sequentially passes through the oil inlet, the oil inlet channel, the low-pressure chamber, and the low-pressure oil outlet circuit. High-pressure oil discharged from the high-pressure oil outlet circuitis the oil that sequentially passes through the oil inlet, the oil inlet channel, the low-pressure chamber, the high-pressure chamber, and the high-pressure oil outlet circuit. The discharge condition, discharge order, and discharge method of the high-pressure oil and the low-pressure oil can be adjusted according to the hydraulic system in which the combined plunger pump is applied. This belongs to the existing technology and will not be explained in detail herein.

The above description is merely a preferred embodiment of the present disclosure and should not be construed as imposing any limitation on the disclosure in any form. Based on the technical essence of the disclosure, any simple modifications, equivalent substitutions, or improvements made to the above embodiments within the spirit and principles of the disclosure shall still fall within the scope of protection of the technical solution of the present disclosure.