1. Field of the Invention
The present invention generally relates to a pump arrangement for front and rear wheel driven motorcycles that are powered by a high pressure hydraulic flow. More particularly, the present invention relates to a pump arrangement that is driven by a rotating shaft and that comprises a piston arrangement that generates a flow pulse or pulse of medium, which piston arrangement has pistons that move forward and backward in a substantially longitudinal direction, and an actuating device for the pistons arranged in association with the shaft.
2. Description of the Related Art
Motorcycles can use a hydraulically operating pump to supply power for propulsion to the front wheel. Such motorcycles are shown, for example, in application PCT/SE2004/001782, which published as WO 2005/061261 on Jul. 7, 2005.
With this type of pump, there is a need for a pump that works efficiently but that has small external dimensions. The space for the pump is often limited and there is a need to be able to reduce the external dimensions by, for example, 40-60% compared with the external dimensions of currently known corresponding pumps. In spite of this need for reduced size, the pump should be able to operate with a very large output (for example, 20 kW) and should have a reliable and functional construction that can work with long service intervals. There is also a desire to be able to arrange for parts of the pump arrangement, for example, the oil supply, the oil cooler, the oil filter, etc, to be common to more than one hydraulic system and also to arrange the pump in such a way that serves the respective hydraulic systems without creating any interaction between these systems. In other words, there is a desire to create a modular construction.
In some embodiments, the actuating device comprises a cross section having a curve of constant width, a so-called Reuleaux cross section, with at least three corners. In a Reuleaux cross section, the distance between each corner and the peripheral surface that is directly across from this corner is essentially the same, irrespective of the rotational position of the cross section around the rotating shaft. The actuating device is also arranged to interact, via the peripheral surface of the cross section, with the carrier devices associated with the piston, during its rotation caused by the shaft.
In a preferred embodiment, the carrier devices are in the form of yokes that are generally rotationally fixed but that are capable of axial movement in the longitudinal direction of associated piston. The actuating device rotates in relation to flanges of the yokes in response to the rotation of an input shaft. The rotation of the actuating device causes the pistons to move in an axial direction that is generally normal to the rotational axis of the actuating device. The pistons move axially within spaces or recesses provided for the pistons in a housing/body, which spaces or recesses can be considered to be cylinders. Preferably there are two or more pistons and associated carrier devices. In some embodiments, the actuating device is provided with an additional layer on the peripheral surface with the layer being rounded off at the corners of the actuating device in order to allow less damaging interaction between the inner surfaces of the flanges and the corners during the rotation. Preferably, the number of corners is odd and can be three, five, seven, etc, in number.
In some embodiments that are arranged and configured in accordance with certain features, aspects and advantages of the invention, the pump comprises a housing with a first partial space for the actuating device and one or more second partial spaces for the cylinders. The one or more second partial spaces receive the pistons and the pistons reciprocate within the one or more second partial spaces. The rotating shaft extends into the first partial space and the actuating device is connected to the portion of the shaft that extends into the first partial space. The carrier devices with the yokes are arranged in the said first partial space. Preferably, the yokes reciprocate in the longitudinal directions of the pistons in response to the rotation of the actuating device, which is rotated by the shaft. In addition, in association with the one or more second partial spaces, the housing comprises outlets for the generated outflow of medium and inlets through which medium is introduced from a low pressure side in a hydraulic system. Each piston can be provided with an internal passage for medium that is open when the piston is in a first longitudinally displaced position in the relevant second partial space. The passage is closed when the piston is in a second position at least partially protruding from the relevant second partial space. An opening and closing arrangement is utilized for each piston. The pump can, in addition, comprise a valve arrangement that carries the flow pulses or pulses of medium generated by the pistons to a hydraulic motor for driving the drive unit for the motorcycle's front wheel. The valve arrangement can comprise spring-loaded devices, for example shims, arranged to be able to be opened and closed to pass parts of or all of the flow pulses to the front wheel's drive unit. Additional further developments will be apparent from the following description and subsidiary claims.
Preferably, the pump can be assembled from reliable components. The pump preferably works with flow pulses or pulses of medium that are close together and that have reduced amplitude, for example considerably reduced amplitude, in comparison to pumps that operate at one pulse per revolution. The new pump therefore can be easily constructed to be very resistant to wear and it is generally less damaging to other system components. The effects on the system thus can be reduced considerably and many advantages can be obtained as far as volume is concerned. No special measures need to be taken as far as space is concerned in connection with the location of the pump. In the case of motorcycles, for example, the pump can be arranged in hitherto unutilized spaces, in spite of the fact that these have minimal volumes, due to the greatly reduced size of the pump.
A currently proposed embodiment of an arrangement will be described below with reference to the attached drawings in which:
In the embodiment of
The pump housing comprises a first partial space 21, in which the actuating device 14 and the carrier device 18 are arranged and operate. The pump housing also comprises a number of second partial spaces 22 in front of the cylinders 19, 20 in which the pistons 16, 17 operate. The pistons 16, 17 can assume first positions in the partial spaces (see the position of the piston 16). The pistons 16, 17 also can assume partially projecting second positions in the cylinders (see the position of the piston 17). The carrier devices 18 are provided with elongated holes 23 (shown in dashed lines) in association with the rotating shaft 15. The elongated holes 23 preferably are elongated in the longitudinal or axial direction of the respective one of the pistons 16, 17 in order to enable each piston 16, 17 to move between the first and second positions.
With reference to
Each piston comprises an outer cylinder 51a and a central part 51b that extends in the longitudinal direction of the piston. The central part 51b has, at its upper portion, a part 51c and the piston is arranged with a cover 51d that can move in relation to the cylinder 51a. The upwardly displacement of the cover 51d can take place against the action of a spring, for example, a spiral spring 51e. In addition, the piston 51 is provided with longitudinal holes, for example five longitudinal holes, one of which is indicated by 51f, that extend in the longitudinal direction of the piston 51. The arrangement with the piston is such that when the piston assumes its fully inserted position in the partial space 56, the cover 51d closes the passage 51f. When the piston 51 moves towards the position in which it is partially projecting out of the second partial space 56, the overpressure on the medium in the space 60 is able to lift the cover 51d and, during this movement of the piston 51, medium can flow from the space 60 to the upper side of the piston 51. During the movement caused by the actuating device 58 towards the fully inserted position of the piston 51, the medium transferred to the outlet 61 can, in this way, be forced via the duct 54 to the outlet 61 in the cylinder housing 53. A pulse of medium is obtained in this way.
A valve or a valve arrangement preferably is arranged at the outlet 61, as shown in
When the piston that operates in the space 56 generates a pulse of medium that enters the duct 54, the device 62 is pressed downwards in the figure and opens the duct 67, with the result that the pulse of medium can flow in through the openings 66 and out in the direction of the arrow 69 through the outlet 70 of the valve or the housing towards the unit that drives the front wheel. When the pulse of medium is forced out via the outlet, the spring 64 thereafter returns the device 62 and closes the duct 67. In a corresponding way, the device 63 is acted upon and opens the duct 68 when the piston 51 generates its impulse via the duct 55. The device 63 returns in a corresponding way to the position shown in
It is recognized that the pump principle has a more general application than being utilized for motorcycles of the above-described type. In an embodiment, the new pump arrangement can be arranged to supply medium to more than one hydraulic system, for example two, three, four, etc, hydraulic systems, that do not interact with each other in association with the provision of medium. Examples of hydraulic systems for, for example, motorcycles, include hydraulic systems for driving the front wheel, for controlling anti-locking brakes, for active control of steering dampers, etc. The arrangement can be divided between oil supply, oil cooler, oil filter, etc, without there being any interaction between the different hydraulic systems 73, 74 and 75 that are connected to second partial spaces as described above via ducts (see the broken lines in
The invention is not limited to the embodiments described above as examples, but can be modified within the framework of the following claims and concept of the invention.
Number | Date | Country | Kind |
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0501415-4 | Jun 2005 | SE | national |
This application claims the benefit and priority to and is a U.S. National Phase of PCT International Application Number PCT/SE2006/000742, filed on Jun. 19, 2006, designating the United States of America and published in the English language, which claims priority under 35 U.S.C. § 119 to Swedish Application Number 0501415-4, filed on Jun. 20, 2005. The disclosures of the above-referenced applications are hereby expressly incorporated by reference in their entireties.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/SE06/00742 | 6/19/2006 | WO | 00 | 10/20/2008 |