Denso Corporation

Toyota Jidosha Kabushiki Kaisha

Yoichi Kobane

Hiroaki Asano

Naofumi Adachi

Tsukasa Yamashita

Shuichi Matsumoto

Hidekazu Hattori

Fumihiro Fujikake

Akira Fujii

Hiroaki Makino

Yoshinori Okuno

Hideo Kamiya

Keisuke Suzuki

Tomoyuki Tsuda

Shinichi Okamoto

Masato Yamada

A fuel injection device () includes a control body () provided with an injection hole (), a nozzle needle () that opens or closes the injection hole (), a pressure control chamber () controlling a movement of the nozzle needle (), an inflow channel () through which high-pressure fuel is introduced to the pressure control chamber (), an outflow channel () through which the fuel from the pressure control chamber () is discharged, and a floating plate () that opens or closes the inflow channel (). In the fuel injection device (), the control body () includes a cylinder () defining the pressure control chamber () in a radial direction thereof, and an inner wall portion () of the cylinder () includes a communication groove () which causes an inflow chamber () that is provided within the pressure control chamber () at a side of the inflow channel () relative to the floating plate (), to communicate with a back pressure chamber () that is provided within the pressure control chamber () at a side of the nozzle needle () relative to the floating plate ().

Fuel injection device

In a fuel injection device, a control body has a pressure control chamber, an inflow port and an outflow port. The inflow port and the outflow port are opened at an abutting surface exposed to the pressure control chamber. In the pressure control chamber is arranged a floating plate for pressing the abutting surface by a pressing surface with the pressure of the fuel to interrupt communication between the inflow port and the pressure control chamber. The abutting surface of the control body is provided with an outer opposite surface portion opposite to an outer edge of the pressing surface in a displacement axis direction of the floating plate, and the outer opposite surface portion has a special depressed portion that is depressed in the displacement axis direction and that extends along the shape of the outer edge of the pressing surface.

The invention has an object for improving response of a fuel injection device. A flow-in recessed portion and a flow-out recessed portion are formed at a press-contacting surface of a floating plate, which is movably accommodated in a pressure control chamber. A flow-in port and a flow-out port are formed at a pressure control surface of a valve body. The flow-in port is opened to the flow-in recessed portion, while the flow-out port is opened to the flow-out recessed portion. When the floating plate is moved upwardly and the press-contacting surface is brought into contact with the pressure control surface, the flow-in port is surely closed.

In a fuel injection device, a pressure control valve is configured to make communication between an outflow port and a return channel and to interrupt the communication so as to control pressure of a fuel in a pressure control chamber, a valve member is configured to open and close a valve portion in response to the pressure of the fuel in the pressure control chamber, and a pressing member is arranged to be reciprocated and displaced in the pressure control chamber. The pressing member has an outer wall surface portion that is opposite to an inner wall surface portion of the control body to be capable of contacting the inner wall surface portion of the control body, and at least one of the outer wall surface portion of the pressing member and the inner wall surface portion of the control body is provided with a recess portion that is recessed to a side separated from the other one of the outer wall surface portion of the pressing member and the inner wall surface portion of the control body.

A laminated piezoelectric element according to the present invention includes a plurality of unit laminates and a plurality of adhesive layers. The unit laminates are stacked together. Each of the unit laminates includes a plurality of piezoelectric ceramic layers and a plurality of internal electrode layers that are alternately laminated with the piezoelectric ceramic layers in the lamination direction of the unit laminate. Each of the adhesive layers is formed between adjacent two of the unit laminates to bond the two unit laminates together. Further, each of the adhesive layers has a thickness of 1 &#x3bc;m or less and an adhesive strength of 1.3 MPa or higher.

Laminated piezoelectric element including adhesive layers having small thickness and high adhesive strength

An object of the present invention is to provide a piezoelectric stack substantially free from deterioration in performance and having high reliability, and a production method thereof. A piezoelectric layercomprising PZT and an internal electrode layerare alternately stacked; the grain boundary-filling factor of a Pb-based glass in the crystal grain boundary of the piezoelectric layeris 95% or more; in producing a piezoelectric stackin which a piezoelectric layercomprising PZT and an internal electrode layerare alternately stacked, unfired sheets for the piezoelectric layerare stacked to produce an unfired stacked body, the unfired sheet containing Pb in excess of the stoichiometric ratio in PZT and having printed thereon an electrically conducting paste for the internal electrode layer, and the unfired stacked body is fired in an oxygen atmosphere having an oxygen concentration of 40 to 100 vol % such that the grain boundary-filling factor of a Pb-based glass in the crystal grain boundary inside the piezoelectric layeris 95% or more.

Piezoelectric stack and production method of piezoelectric stack

A laminated-type piezoelectric elementis provided, which comprises a first external electrode layer, which is located at a side area of the laminated-type piezoelectric element, is electrically continuous to internal electrode layers, and comprises plural expansible and contractible opening portionsin a stacking direction of the laminated-type piezoelectric element. As the first external electrode layeris connected to the laminated-type piezoelectric elementwith an electrically conductive adhesive memberand the electrically conductive adhesive memberis narrower than the first external electrode layer, the electrically conductive adhesive memberpenetrates into the opening portionsof the first external electrode layerto form connections in a shape of an anchor. Therefore, the first external electrode layeris firmly connected to the laminated-type piezoelectric element

Laminated-type piezoelectric element

A multilayer piezoelectric element has a pair of outer electrodes and a multilayer ceramic body composed of piezoelectric layers and inner electrode layers which are alternately stacked. The outer electrodes are formed on a pair of electrode connecting surfaces in the outer circumference surfaces of the multilayer ceramic body. Each outer electrode electrically connected to the inner electrode layers through connecting material is composed of a fixed part, a free part having plural expandable-openings, and a rigid part. The fixed part is electrically contacted with the connection material. A sectional area of the rigid part is rather than that of each of the fixed part and the free part in a width direction of the outer electrode. Each outer electrode has at least one part where the fixed part, the free part and the rigid part are arranged in order in the width direction.

Multilayer piezoelectric element

A laminated piezoelectric element () comprises a laminated piezoelectric element () piezoelectric layers () composed of a ceramic capable of expanding and contracting upon application of a voltage, and internal electrode layers (and) that supply voltage to the piezoelectric layers, the internal electrode layers and piezoelectric layers being alternately provided, a first external electrode layer () provided on a side of the laminated piezoelectric element () and electrically connected with the internal electrode layers (and), and a second external electrode layer () provided on a side of the laminated piezoelectric element () and electrically connected with the internal electrode layers (and) via the first ecternal electrode layer wherein there are specific external electrode width relationships.

Growing community of inventors

Kuwana, Japan

Yoichi Kobane